Jtljata, Bffta gnrk Carp"nt-Tr Estate CorneHUnWersityUbrarv TH 7577.C66 191* Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924022801173 THE IMPROVED COCHRANE STEAM-STACK & CUT-OUT VALVE HEATER & RECEIVER '700 SERIES t PATENTED! The greatest advance in the art since the advent of successful open feed-water heaters ts application in connection with commer- cial systems of exhaust steam and hot water heating, Together with information and tables useful to heating and ventilating engineers and contractors. Copyright, 1914 by HARRISON SAFETY BOILER WORKS ESTABLISHED 1863 17TH ST. AND ALLEGHENY AVE. - PHILADELPHIA, PA. (600) COCHRANE HEATING ENCYCLOPEDIA Corliriitir SliniN-Sfarl: iiikI Ciit-Oiil ]'iilve Ilcalir ati,l lirciivrr rqiiipped irilli e.clra liirgr sciitinitor fur jiiirifijing of oil the .s'i;r/)/»,s c.rhaust /Kissing lo Uir hfiilini/ si/slriii, ns well as ihnl i-iiuxuiucil ill liriiliiig (he lioiter fecil-widcr. INTRODUCTORY Since the publication of the first and second editions of this book we have installed the Cochrane Steam-Stack and Cut-Out Valve, or Surplus Exhaust, Type of Heater and Receiver for many of the largest concerns and most prominent engineers, such as : Canadian Pacific R. R. Swift & Co. Harvey Hubbell Electrical Works Delaware & Hudson Co. Pan-American Bureau J. G. Brill Car Co. Freedmen's Hospital (Washington) Moore Push Pin Co. United States Navy National Biscuit Co. Felt & Tarrant Mfg. Co. Philadelphia Y. M. C. A. National Lead Co. D. L. & W. R. R. Helvetia Milk Condensing Co. The Wanamaker Store C. C. C. & St. L. R. R. Co. Roberts College (Constantinople) C, M. & St. P. R. R. Fort Monroe Artillery School McCray Refrigerator Co. Fairbanks, Morse & Co. U. S. Biological Station Ingersoll-Rand Co. American Chicle Co. Ansco Camera Co. Ames Shovel & Tool Co. Ward Bread Co. Baltimore Masonic Temple Cornell University Boston Opera House Pennsylvania R. R. Carter Ink Co. Yale & Towne Mfg. Co. Lowell Textile School Eastman Kodak Co. Geo. E. Keith Shoe Co. Oneida Community Knox Auto Co. R. J. Reynolds Tobacco Co. Union Pacific R. R. American Sheet & Tin Plate Co. Etc., Etc. We have developed several new adaptations and improvements, such as the Cochrane Metering Heater (Combined Open Feed-Water Heater and Hot Water Meter), Combined Meter and Hot Water Storage Tank, etc., as described herein. We have also introduced the Cochrane Multiport Safety Exhaust Outlet Valve, an improvement over the ordinary back pressure valve in that it has a number of disks instead of only one disk (hence multiplied safety from sticking), and in that the back pressure can be easily adjusted merely by turning a hand v^rheel, v^^ithout hovv^ever, any possibility of exceeding a pre- determined back pressure, nor of the valve being jammed by overtighten- ing of glands or obstructed by external objects. This valve, in connection with the Steam-Stack and Cut-Out Valve Heater and Receiver, renders the installation "fool-proof" all the vfay from engine to atmosphere. The Steam-Stack Heater and Receiver is adapted for use with any of the many excellent systems of exhaust steam heating, including the vacuum systems and other special arrangements, as well as the gravity return and back pressure systems, and we invite the cooperation of proprietors of the several systems in the further amplification and improvement of the descriptive and illustrative matter herein presented. It should be noted that the piping arrangements shown in photographs and draw- ings reproduced in this book are not necessarily in every case to be considered as the best or most suitable arrangements. Our engineers will, however, gladly give suggestions as to the best and most economical arrangement for specific conditions. COCHRANE HEATING ENCYCLOPEDIA TOPICAL INDEX What are the five essentials of an exhaust steam-heating system? This is treated briefly on page 9, and at length on pages 47 to 55. In what ways are the ordinary methods of connecting open feed-water heaters to exhaust steam-heating systems faulty ? See pages 1 1 to 15. Just what is gained by using the Cochrane Steam-Stack and Cut-out Valve Heater and Receiver ? First it saves $50 to $500 on the cost of the equipment, as com- pared with the installation of an independent separator in a by-pass around the ordinary heater and receiver, it occupies less space, is simpler to operate, and is fool-proof. See pages 1 7 to 27. What are the structural features to be looked for in an open heater? See pages 29 to 35. What are the peculiar advantages of the horizontal cylmdncal heater? 5ee pages 37 to 39. What special combinations can be made with steam-stack and valves for engines exhausting freely to atmosphere, and where more than one heater is installed? See pages 4 1 to 43. How should I draw my specifications so that I will get a good heater and receiver? See pages 45 and 46. Is there more than one system of exhaust steam heating available for my use, and are the systems covered by patents? Twenty-seven different systems for utilizing exhaust steam for heating are described m this book. The patents still in force relate chiefly to details. See pages 55 to 95. Can exhaust steam be used in connection with hot blast heating and dry- ing systems? Yes, see pages 1 1 to 104. Is it possible to combine the advantages of an open feed water heater with those of hot-water heating? This may be done to great advantage in many cases, as explained on pages 1 05 to 1 07. By the use of our patented system it is also possible to run the engines condensing, carrying a vacuum correspond- ing to the temperature of the water required in the heating system, usually 20 ins. or more. How can exhaust steam be used for heating in connection with plants that are operated condensing? si i I TOPICAL INDEX There are at least eight different ways m which this may be arranged, according to the local conditions, and by using compound engines, low pressure and mixed flow turbines, etc., as explained on pages 107 to 117. Can exhaust steam be used to advantage for ice-making and refrigeration? Yes, either with the compression system or the absorption system. 5ee pages I 19 to 1 22. What IS the best method of determining the efficiency of a plant, the best kind of coal to use, etc.? Instafl a Cochrane Metering Heater or a Cochrane Independent Meter for use in connection with open or closed heaters, as ex- plained on pages 1 23 to 1 27. How may I prevent the formation of scale in my boilers? By treating the water chemically at the same time it is being heated, in the Sorge-Cochrane Hot Process Softening System, as explained on pages 1 28 to 1 30. Can Separators be obtained independently of Cochrane Heaters for re- moving oil and water from steam? Yes, both for live steam and exhaust steam and special separators in connection with low pressure turbines. See pages 131 to 136. How is the back-pressure most conveniently controlled in exhaust steam heating systems? By means of a Cochrane Multiport Safety Exhaust Outlet Valve, by which the pressure is readily and quickly adjustable from the engine-room floor, and with which there is absolutely no danger of sticking or over-pressure. See pages 137 to 142. When exhaust steam is supplied to a mixed flow turbine or steam is with- drawn from an intermediate stage of the turbine for heating or drying purposes, are any special valves required? Yes, flow valves for preventing vacuum from backing up into the engine exhaust line, and check or extraction valves for preventing steam flowing back into the turbine and overspeeding it. See pages 142 to 144. Is there any publication in which I can find condensed all the essential rules, data, coefficients, etc., required in designing an exhaust steam heating system? See pages 145 to 192. Where can similiar information for hot-water heating be found ? Pages 193 to 198. COCHRANE HEATING ENCYCLOPEDIA Cochriini Sli nui-S/ncl.- end Cul-Oiil Vnlrf Iltali r ninl li'irriver ilisldUi/'l ill cniiln'clinii inilli (III i:.rliiiiiKl xtciiiil halting sysliin in a llicalrc. ECONOMY OF EXHAUST HEATING HEATING WITH EXHAUST STEAM The utilization of exhaust steam offers immense possibilities for profit. The steam exhausted from an engine is still capable of delivering (at a temperature of 212° F., or higher, according to the back pressure) from 70 to 80 per cent, as much heat as when it left the boiler. If a large portion of the exhaust be used for heating or drying purposes, the power generated by the engines becomes a nearly costless by-product, or from another point of view, the heating is practically free of charge. Nevertheless in many plants exhaust steam is still wasted to atmosphere or is sent to a condenser, or electric current is purchased for power, while at the same time coal is being burned to produce live steam for heating purposes. Such wasteful practice is most often due to lack of familiarity with the best methods and means of utilizing exhaust steam. The use of exhaust steam for heating purposes not only oft'ers the possibility of cutting the fuel bill nearly in half, but by conserving the pure condensed returns from the heating system and utilizing them as boiler feed it is in many cases possible to reduce the water bill by 80 per cent, and at the same time to cut off a large part of the expense of removing periodically from the boilers the scale that is deposited from most natural waters. The most profitable use to be made of exhaust steam is in heating the boiler feed-water, since not only is heat conserved and fuel saved thereby, but the boilers are protected from temperature strains, the water is purified by the driving off of gases and the consequent precipitation of carbonates, and the capacity of the boilers is increased in tlie ratio borne by the heat imparted to the feed-water irom exhaust steam to the total amount of heat required to convert the cold water into steam, or from 10 to 16 per cent. Any surplus of exhaust steam remaining after heating the feed-water becomes avail- ah)le for heating, drying, etc., by utilizing it in any of the well- known vacuum or back-pressure systems and with direct or indirect radiation, as conditions may dictate. COCHRANE HEATING ENCYCLOPEDIA g, ^ APPARATUS FOR EXHAUST HEATING I j A complete exhaust steam heating or drying system should include apparatus to perform all of the following functions: (For more complete treatment see pages 47 to 55). 1- — A feed-water heater to heat the boiler feed; 2. — A thoroughly efficient oil separator to purify the steam so that the heating system will not become fouled with cylinder oil and so that the exhaust con- densed in heating the feed-water and condensed in and returned from the heating sj'stem can safely be utilized as boiler feed; 3- — A :::; of large capacity to drain the above separator and to pass to waste any overflow from the heater; ■1. — A returns tank to receive the condensation from the 1 1 heating system, and from the feed-water heater if the 1 1 latter l.>e of the closed or tultular type; ji 5. — Afloat and valve, or equivalent arrangement, for 1 1 admitting cold water automatically from the city 1 1 mains or other source to the hot well or returns 1 1 tank in ciuantities required to make up losses due to 1 1 leakage, to escape of exhaust steam through the back 1 1 pressure valve, to use of water for industrial purposes, 1 1 lavatories, etc. 6. — A back pressure valve capal)le of easy and quick regulation for preventing the pressure in the heating system from building up above a certain predeter- mined amount. ^ In some cases a pump — sometimes an automatic pump and / i receiver or a vacuinn pump — would Ije installed to handle the I ^ returns. ^ I Such a collection of apparatus is outlined in the lower and left side of page 8. Our innovation in oi)en feed-water ^ ^ heaters and receivers, the Cochrane Steam-Stack and Cut-Out I I Valve Heater and Receiver, or Surplus Exhaust Heater, shown ^ I in the upper right-hand corner, makes ioossil)le the replacement 1 1 of this bulky, complicated and exiDcnsive combination of \% independent appliances by a single, self-contained apparatus. COCHRANE HEATING ENCYCLOPEDIA TO ATMOSPHERE li. One of severiil {/noil irni/a of iiiiDiirli ikj up Ihv uhl-sli/lr Coclirom: Uiiilcr and Receiver ivilh o grcril// nluni r.rh.fiusl slco/n hoolinq >://s/r//i. ]\'licrc a heater is to be inyJolliit in lliix nionncr, core xlnnild be l(il:cn lliol lln- omoinil of steam exhausted Inj llie enijinv will mil nl onij linn: exrccd Ihe eo jiiirilij of Ihe oil separator allorhrd lo lln' Iniili r. Xole, nniri'OVn-. Unit lliix hcoler coninil be cut out withoni yhidliinj doo'n On' inlirc plonl, while ndlli a ('orlironr Sleoni- Siack and Cnt-Ont ]'olrc Heatir and Recni'ir, the hiiitir conid lie inololed without inlerfrrinfi with tin' opiridion of Ihe enijini: or heotinij xi/slini. See page 4S- 10 FAULTS OF COMMON SYSTEMS SHORTCOMINGS OF A COMMON ARRANGEMENT FOR BACK PRESSURE HEATING SYSTEMS Before proceeding to a description of this Heater and of tlie great improvements in exhaust steam heating practice which it maizes possible, attention is directed to page 10, wliich sliows a common and satisfactory method of piping up a Cochrane Heater anclReceiver of the old standard t^'pe in connection with an exliaust-steam heating system. This is in itself a marlied ad- vance over the closed heater arrangement, since the open heater here performs all the functions of tlie five or six separate pieces of apparatus sliown at the left on page 8. The heater, however, must be of a sufficientlj^ large size to have an oil separator capa- ble of purifying the entire volume of exhaust steam delivered by tlie engine, which generally would call for the installation of a feed-water heater much larger than would Ix' needed for the water-heating reciuirements. Moreover, this arrangement includes no provision for cutting the heater out of circuit for cleaning, renewal of filtering material, etc., while the heat- ing system is in (jp- eration. To remedy tliese shortcomings the heater may be airanged with a by- ])ass, as at the left on page 12, but the latter layout not (udy has the disad- vantage of being more costly, re- (puring three addi- tional gate valves, a tee, an elbow, two extra lengths of pipe and eight ex- tra gasketed joints, InslallaUon of Old Style Cochrane Heater and c p r W . 1 1 ^ 1 v Receiver, complete with independent oil separator in "ui is ,. eiiou.. i^\ hij-paes. Note extra valves, fittings, elbows, tees, trap, deficient in other etcascomparedwiththeCochraneSteam-Stackand ^^^.^^ ,„ „„> „,,„,., Cui-Ouiy'drfHcalcraridRcceirer.howvonpagelS respects, and e\ en COCHRANE HEATING ENCYCLOPEDIA 4 ' ¥'. '4. 12 FAULTS OF COMMON SYSTEMS Cochrane Steam-Stack and Cut-Out Valve Healer in connection with tieating systein of a factory huihiinej. dangerous. For one thing, it does not provide for the purification of the steam that passes to the heating system when the heater is cut out; and for another, if the two valves in the vertical pipes should both be closed at the same time while the heater is in service, the engine might be stalled and the heater would be subjected to high steam pressure, for which in general it is neither designed nor intended, and which could not occur if the installation were made as shown at the right on page 12. 13 COCHRANE HEATING ENCYCLOPEDIA 14 FAULTS OF COMMON SYSTEMS Cnvhi-diir Slenm-Slnrt m,,/ Cut-Oiil Vnir' Ilniirr mid h'li-iirrr i iixl'ilhil In citiuicrtioii irilli tlic rxliijiifil .•iliaiii liviili iif; xijsti'iii nf a lixtili mill. A MORE COMPLICATED AND EXPENSIVE BUT STILL IMPERFECT ARRANGEMENT The separati(jn of oil from tlio sviri^lus exhaust steam is ]iro- vided for Ijy the arrangement shown at the left on page 14, where an inde])en(h"nt oil se]iarator is installed in the by-i)ass around the heater. A trap is included for draining the in- dependent separator at all times, as when the heater is cut out of service for cleaning and when the trap on the heater could not, therefore, be used for draining the independent separator. The independent separator must be large enough to purify the entire maximum volume of steam delivered, since it will be required to pass all of the steam while the heater is cut out or when the returns come back at a higli temperature. The element of danger in the arrangement shown on page 12 is eliminated in this arrangement, but a furtlier additional ex- pense may be incurred for an exhaust head to protect roofs, etc., from the water and oil carried out by the unpurified ex- haust steam escaping through the back-pressure valve. 15 COCHRANE HEATING ENCYCLOPEDIA « ^ s ; S :s ^ ^ 1^- -^ Si- 16 STEAM-STACK d, CUT-OUT VALVE HEATER In order to remove water and oil from the steam passing outboard, the arrangement shown on page 16 can be adopted; here the piping has been simplified somewhat by using what is known as a long sweep "preference" tee, that is, a connection which will give the heater the first choice of the steam, so to speak, but at the same time permits an easy flow of the steam to the heating system or to atmosphere. THE COCHRANE STEAM-STACK AND CUT-OUT VALVE HEATER AND RECEIVER The Cochrane Steam-Stack and Cut-Out Valve Heater and Receiver saves both cost and space, as will be apparent from a comparison of the apparatus shown at the right on pages 12, 14, 16, 18 and 19 with the more cumbersome arrangements shown at the left. The saving in cost of fittings antl lal:)or of in- stallation from using this improved Heater and Receiver will in many cases amount to more than 25 per cent, of the whole cost of the feed-water heating eciuipment, or from $50 to .S500, according to the size of the plant. As compared with the best arrangement possible with the ordinary open heater, the Cochrane Steam-Stack and Cut- Out Valve Heater and Receiver represents a more complete equipment, since it performs the functions of, and thus saves the cost of : ^pprox. Cost in 200 H. P. Installation 1. — An independent oil separator $93.00 2. — An independent trap for draining the independent oil separator 39.00 3. — A drip line from the separator 1.80 4. — An independent connection from trap to waste or sewer 2.00 5.— A flanged tee 24.00 6. — One or more flanged gate valves 9.00 7. — A number of companion flanges, gaskets, bolts, etc. 6.00 8.— Extra labor 12.00 9. — In many cases an exhaust head is saved 78.00 Total extras required in 200 H.P. plant with ordinary Heater and Receiver to match Cochrane Steam-Stack and Cut-Out Valve Heat(>r and Receiver $264.80 This saving is more than 70% of the cost of the heater. 17 COCHRANE HEATING ENCYCLOPEDIA STEAM-STACK & CUT-OUT VALVE HEATER « i Comparing the Cochrane Steam-Stack Heater with the ar- rangement shown on page 14, the appliances saved com]irise two Uu-ge gate valves, two tees, one ell, two long nipples or short pipe lengths, and ten flanged and gasketed joints, besides the independent oil separator and trap, with piping and fittings. A comparison of the Cochrane Heater with a com])lete closed heater arrang(>ment W(.)uld be still more in its fa^•or, since the Coclu-ane performs the functions of heater, liot well, muffle tank, skimmer, filter, make-up water regulator, etc. r-[-. |...., .^>' ^-L.,- ;::-*- ■A-i^jj il; V: r""! i -K? .._|.. , -tfi , -;:iv ...J-. .J Comparison showing, at the left, the Extra Vati'r.i. FitlingK, Sipdi-ntor. Trap, etc., required for an Ordinary Heater and Receiver I nxlidliition, vhieh at the he^t is hut em Imperfect E(pi indent if the Ciielimne Stenni-StncJ; unit Cut Out Valve Heater and Receiver shown at tin: riylit. a I! i '4 THE EXTRA LARGE SEPARATOR OF THE COCH- RANE STEAM-STACK AND CUT-OUT VALVE HEATER AND RECEIVER The distinctive feature of the Cochrane Steam-Stack and Cut-Out Valve Heater and I^eceiver is the oil separator, which is of much larger cajiacity in proportion to the lieater tlian are the separators on other tj-pes of heaters. This separa- tor is of sufficient capacity to purify an amount of exhaust steam corresponding to the horse-power rating of tlie lieater, the latter being based upon the capacity of the heater for heat- ing l)oiler feed-water. In other words, the separator on the 19 COCHRANE HEATING ENCYCLOPEDIA ^SURPLUS EXHAUST PURIFIED OF OIL EXHAUST INLET PURIFIED EXHAUST DRIP FROM SEPARATOR TO STEAM TRAP Dingrnin Shniring hnlh Ciii-Out VaJivn in upcn posilion. 20 A ^ STEAM-STACK & CUT-OUT VALVE HEATER heater will receive and purify of oil all exhaust steam gen- erated from the water handled liy the heater, up to the rated boiler horse-power capacity of the heater. An interior view of the Cochrane Steam-Stack and Cut-Out Valve Heater and Receiver is shown on page 28. Steam enters from the right into the separator, which is of the single, verti- cally-ribbed baffle type. The water and the oily emulsion flow- ing along the bottom of the exhaust pipe are diverted into the well of the separator, where they are removed from the action of the steam current and whence they drain to the trap below. The flying particles of water or oil, whose momentum tends to carry them in a straight line and which weigh about 1600 times as much as eciual volumes of steam at atmospheric pressure, shoot on through the steam when the direction of motion of the latter is changed by the baffle and impinge against the latter, while the steam passes around the sides of the baffle and enters the heater or goes to the heating system. The liquid particles cannot bound back and they cannot be pushed sidewise in the direction of the current of steam because the ribs prevent. The water and oil then run down directly into the well or lower part of the separator, which, as just stated, the steam current does not enter. The baffle is self-cleaning, since the oil is continually washed down into the well by the water. THE STEAM-STACK AND THE CUT-OUT VALVES After the baffle there are two paths open to the steam, viz. : into the heater chamber, which will take only as much exhaust steam as is recjuired to heat the water, and through the outlet or "steam-stack" at the top or side of the separator, by way of which the remainder of the steam must therefore pass. The opening into the heater chamber is con- trolled by a special valve, which when open occupies such a position that the heater has the "preference" for the steam. That is, in its open position the valve deflects a portion of the steam from the steam stack and directs it into the heater, although at the same time any surplus steam can readily escape through the surplus outlet. In its closed position the valve is held firmly to its seat by the pressure of the exhaust steam, as well as by springs. Because of this spring loading the valve acts as a relief for any pressure that may accumulate within the heater, as from the 21 COCHRANE HEATING ENCYCLOPEDIA f i. EXHAUST INLET SURPLUS EXHAUST PURIFIED OF OIL INTERIOR A OF HEATER/ ROTARY CUT OUT VALVE DRIP FROM SEPARATOR TO STEAM TRAP WASTE DiiKjniiii sliiiu-'uiij vidrc in xr iKirnlcr rhtsnl nnd rain- hi Ira p juxl nhniil III clnvi' or 0/ (■/(. Xnlirr pilnl iir III/-/ r/.s.s- (;; Hun i/i nj rning. 22 STEAM-STACK &, CUT-OUT VALVE HEATER discharge or leakage of live steam tra])s or otherwise. It is therefore superior to positively held valves of disk or gate or other t\ pe, becavise Safer — because Fool Proof. The trap attacheil to the heater receives the drips from the separator, ami also takes care of overflow from the heater, as in case of derangement of the cold water valve or when the level of the water is raised intcntionall}- for the purpose of skimming off floating impurities. In order that steam may not pass from the separator through the drip pipe and the trap into the heater when the separator cut-off valve is closed, as when the heater is to be opened while the heating system continues in operation, a second cut-oft' valve is provider I to chjse the opening between the heater overflow and tlie traj). THE SINGLE LEVER CONTROL When the heater is to l)e cut out of service for cleaning or inspection both the valve in the se])arator and that in the traji must be closed, and in order to insure that l)otli will be o])ened or closed at the same time and to render their operation more convenient, an improved combined valve gear has been devised, consisting of cranks on each valve spindle and a connecting rod, so arranged that when upper valve shuts off while the lower valve is still o])en, as shown on page 22, and tlien remains stationary while tlie lower valve com- pletes its rotation. In this way the closing of the upper valve 23 COCHRANE HEATING ENCYCLOPEDIA SURPLUS EXHAUST PURIFIED OF OIL EXHAUST INLET INTERIOR OF heater; ROTARY Cut out valve PURIFIED EXHAUST DRIP FROM SEPARATOR TO STEAM TRAP WASTE Both mli'cs rloseil. llualvr run now he o lie mil for itispvction or cleaning, while sejxirdlor conliniicf; to piirif!/ e.t)ian>;l slviini piiSKing to liedtinii si/.stem. 24 STEAM-STACK &. CUT-OUT VALVE HEATER takes place while there is still steam pressure in the heater to balance the pres- sure on the separator side of the valve. Subsecjuently the lower valve closes, cut- ting off all communication with the body of the heater, after which any steam con- tained in the latter will be condensed or will escape through the vent pipe. After both valves are closed the operating handle can be removed from its spindle before unbolting the clean- ing doors of the heater, thus making impossible the opening of the steam valve while the heater is open and rendering the heater "fool- CochrnneSkcim-Sliickcniil Cul-OnI ]'ob:e Heater and Receiver installed in a textile pleint proof." In reestablishing communication between the sepa- rator and the heater, the lower valve will first swing through a sufficient arc to permit steam from the separator drain pipe and trap to enter the heater, equalizing the pressure on the two sides of the steam valve before the latter begins Cochrane Steam-Slack and Cnt-Oul Valve Heater and Receiver in connection wUh a factory heating system. COCHRANE HEATING ENCYCLOPEDIA .■.. 4(^jm=^ _^- linll, Wilrrs OiH-ii Upixr 1 iilri .\iiirly CIdsviI PlKiliKjruiih^i ,if llnitir irilh SrjHirnlnr luiil Trap lieiiiiirnl, Sliniviiig Ciil-Oiil \'(ilr<'K ill Four Siirr('.- easy to open, easy to get into, and easier to clean than any boiler. The trays are readily removable and even the smallest heater is provided with at least one opening of such dimensions that a man can enter. ft is absoluteh' essential that a reliable arrangement he provided f heater is controlled at all times by a ventilated, seamless cojiper float of the tyi)e and weight used for jiressures of lOt) lbs. per Sfj. in. The float stem is set at such an angle tliat anv \\ater which may collect within the float will at once pass through its hollow stem and show u])on the outside of the heater. Due to its large displacement and long levei-age, it has ample power to control the balanced valve in the cold water line under any pressure u\) to, say, 30 lbs. per scj. in. 32 CONSTRUCTION OF HEATERS */ HEATING TRAYS AND CLEANING DOORS The heating trays for exposing the water to the steam are so arranged that the exhaust steam can freely reach the water at all points. The openings for the introduction and removal of the trays arc of large size, and the doors, excepting on the smaller sizes, are hinged and provided with quickh'-placed fastenings. The trays slide easily in and out upon guides. For carrying whatever filtering material is used, perforated cast iron plates are placed about four inches above the bottom of the heater. Cleaning doors are furnished of such size that the filtering material can be shoveled in and out when recharging is necessary'. A hood over the pump supply opening extends down to the line of the perforated filter plate and the water must pass through the filter bed. The hood is ventilated to the steam space to insure solid water in the supply line and prevent syphoning. COCHRANE OPEN HEATERS VS. CLOSED HEATERS. Closed or pressure heaters were in general use before the Cochrane Open Feed Water Heater and the Cochrane Oil Separator became known, and for the Vx'nefit of those who have not had experience with both kinds of heaters, we present here a brief comparison of the relative advantages of the two types : The Cochrane Heater condenses and saves from the exhaust steam pure hot water, in amounts ranging from one- tenth to one-seventh of the total l)oiler feed supply, while the closed heater must waste its condensed steam to the sewer, unless protected by an efficient oil separator. The Cochrane Heater saves the heat contained in the condensed steam, whereas the closed heater allows it to go to waste. The first cost of a Cochrane Heater is lower than that of a closed heater, except in the very smallest sizes. The cost of installing a Cochrane Heater, including the pipe connections, is generally less than for a closed heater, especially when the extra appliances required to sujiplement the closed heater are taken into account. There is practically no depreciation of a Cochrane Heater, while a closed heater rusts, is affected by pitting, suffers from 33 COCHRANE HEATING ENCYCLOPEDIA Coflimne SltiiinSliicI: titnl Cnl-Oul \'(ilrr Heater atnl Hii-tierr iri^tnllrd in tlir ])Owrr jilnnl i>f a xlciuri rnilirni/. 34 CONSTRUCTION OF HEATERS galvanic action, becomes loose at the joints from expansion and contraction, and is injured by cleaning tools, requires frequent renewal of tubes, etc. A Cochrane Heater is generally operated under only a few ounces or with heating systems under a few pounds pressure, whereas a closed heater is under full boiler pressure, and the working of the joints soon results in leakage. A Cochrane Heater is always capable of operating at full capacity and efficiency, no matter liow long it may have been in use, since the steam comes into direct contact with the 'i water. The closed heater, on the other liand, licgins to fall ^ off in efficiency and capacity from the very first clay's use, ^ due to deposits of oil on one side of the tube surfaces, and the ^ accumulation of scale on the other. The Cochrane Heater purifies the water by driving off corrosive air and gases and by precipitating carbonates and I ft depositing them, together with sand or mud, in the settling I I chamber, or filtering them out or disposing of them by skim- ?• *' ming, whereas in the closed heater all of these impurities are pumped through to the boiler. I All parts of the Cochrane Heater are easily accessilile, I ''": whereas to reach the interior of a closed heater, it is necessary to break steam-tight joints, remove gaskets, etc. The materials of which a Cochrane Heater is constructed are durable, and are not su})ject to corrosion by ordinary boiler feed water, wliereas the shell and sometimes the tubes of closed heaters are of thin steel, a metal peculiarlj^ subject to corrosion. A Cochrane Heater will carry an excessive overload, and will give full heating efficiency while so doing, whereas a closed heater throttles the exhaust steam when the load exceeds the normal amount, making it still harder for the engine to : carry the overload. At the same time, due to the fact that the heat must be transmitted through the metal of the tube, the temperature to which the water will be raised falls off rapidly as the load increases. The Cochrane Heater assists in the maintaining of high vacuum in condensing systems by driving off air and gases from the feed water before they enter the boiler, thus ]iutting less work upon the condenser vacuum pumps. With a closed f'- , heater all air and gases pass to the boiler, from which they go 35 COCHRANE HEATING ENCYCLOPEDIA Ej'lni biri/c Se/Kir/ilor inilli StrdiH-Slcck ntiil C'liJ-Oi/l \'(ilrrs (ippl/ed (n a Cnrjn-nur Hnri'iinlnl ( ' uJifnlncnl }}rnla\ requiring "iilti IfO/ilcd iivoni . 36 HEATERS FOR SPECIAL CONDITIONS to the condenser, whence they must be removed by extra large and costly vacuum pumps, at an expenditure of an ad- ditional amount of power. The Cochrane Heater is a hot water storage tank and may be used as a receiver for drips from heating coils, drying rolls, heating systems, etc. It is an open tank and may receive water delivered intermittently, although the boilers are being fed continuously. These functions are not performed by a closed feed water heater, which must be supplemented by a hot well, receiver pump or return steam trap, at extra expense. In addition to the foregoing, we now offer the Cochrane Steam-Stack and Cut-Out Valve Heater and Receiver, which saves the cost of an independent oil separator and trap. We also supply the Cochrane Metering Heater, (see page 123) which provides not only all the functions of an orater and receiver to the exhaust steam heating system and to arrange for the connection through the back pressure valve to atmosphere, but it ma}^ even be necessary to douljle back with the piping, which is expensive in space and monej^ with a Lnrge pipe. Then, too, with the ordinary feed-water heater and receiver, a phice must be found for the indepen(h'nt oil separator and a line of piping must be run from the latter to a trap placed on the floor or on a bracket, with a driji line from the trap to sewer. Further, good engineering calls for quite a number of valves and fittings to be used for cutting out different parts of the arrangement or piping in order that they may be cleaned, replaced or repaired without shutting down the entire plant. The Cochrane Steam-Stack Heater and Receiver obviates the necessity of the independent oil separator and of the valves, tees, trap and connections, and makes it possible to run the piping in a direct course from the engine, through the heater, and then to the heating system and out-board exhaust. Where headroom is an important consideration, an extra- large or surplus separator is furnished on a Cochrane Hori- zontal Cylindrical Heater, the separator having plenty of capacity for handling all of the exhaust steam, while the cylindrical heater shell provides exceptionally large water storage in limited headroom. The illustrations on pages 36 and 37 illustrate how this idea is carried out. In each of the heaters shown the separator covers the whole end of the heater, or rather the separator and the drainage trap are combined in the ring casting at the end of the heater, while the main shell of the heater is con- structed something like that of a cylindrical surface condenser, being closed at either end by circular plates. In the plate at the separator end are located the steam entrance and the overflow openings. In the ring casting serving as trap and separator shell are formed the exhaust outlet opening and the jaacking box for the trap float spindle. Besides the arrangements shown by the accompanying drawing.s, we are prepared to supply special layouts to suit exceptional situations. We like to solve problems connected with the utilization of exhaust steam, and in any specific case perhaps we can help with suggestions and plans. 39 COCHRANE HEATING ENCYCLOPEDIA ^SURPLUS EXHAUST PURIFIED OF OIL EXHAUST INLET DRIP FROM SEPARATOR TO STEAM TRAP PURIFIED EXHAUST WASTE 5 ? Cross scclion of Surplus Exhaust Srpiirolor mid trap (ilUiclicil In Cochrane Healer and Reeeiver wilhont Cul-Out ]'nhrs {.'HID .Series), shoiving course of xirani and walcr. 40 HEATERS FOR SPECIAL CONDITIONS STEAM-STACK HEATERS WITHOUT VALVES In some plants it is not found necessary to provide for cut- ting the heater out of service while exhaust steam is passing through the separator, and in such cases the valves between the separator and trap and the heater shell are not required. The Cochrane 900 Series Steam-Stack Heaters and Receivers, shown on pages 38 and 40, have the extra large separator with the steam stack at the top, but are not fitted with the two cut- out valves, which is the only difference between these and the 700 Series, or Steam-Stack and Cut-Out Valve, Heaters. HEATERS FOR ENGINES EXHAUSTING FREELY TO ATMOSPHERE The heater described in the foregoing pages is of the receiver type, that is, it is designed and adapted to be used in connection with engines exhausting into heating or drying systems, and for this reason is made extra strong, is arranged to receive, reheat and temporarily store the condensed returns, and is provided with a float operated trap for permitting the escape of flrips from the separator and of overflow from the heater without passage of steam. Where a back pressure valve is not to be used, it is not neces- sary' that the heater be designed for pressure, nor is the trap rec[uired, since a plain water seal will suffice to prevent waste of steam through the drip connection. We therefore build heaters ecjuipped with the extra large separator, the steam-stack and the cut-out valves, but otherwise correspond- ing in all respects to our standard open feed-water heaters. The steam-stack and valves are frequently effective in simpli- fying and reducing the cost of piping connections. The great advantage of this style of heater is that it can be cut out of service without interfering with the service of the oil separator. These heaters are known as the "600 Series." See page 42. THE COCHRANE PATENTED MULTIPLE UNIT HEATER ARRANGEMENT Even where the stack is not required, the cut-out valves are convenient and save the cost of separate valves, and they can be applied to any of our standard heaters. Where several heaters are to be installed together, the complication of piping 41 COCHRANE HEATING ENCYCLOPEDIA Till' C'ucliniiic lli'iiirr luiriiii/ Slrdiii-Sldvl.- (itid Cnl-Oiil Vnh'r lint with Wiitir Sent iiiatiiiil iif Tritp: intiijitrit fur use until iritli engiiica cxIidUstiiKj J'rirtij to iitiiiOf in- stalled in duplicate in large power jjlants and the exhaust of all the auxiliaries is brought together into one large exhaust main with branches to the two or more heaters and a single outlet to atmosphere. In such cases we provide for cutting out any or all heaters with a minimum expense for valves and piping and with the maximum of convenience and simplicity. Such an application of the cut-out valve is shown on page 44. All of the exhaust steam is brought together in one common main, from which it flows into the two heaters, which are operated "in parallel," so to speak. To insure that the two heaters will be equally loaded, the water supply to each is proportioned by a dividing box consisting of a chamber in which there are two ^'-notch overflow weirs. If the two heaters are of different size, as where one has Ix'en installed in a growing plant to help out an older heater, these notches are made of appropriate dimensions. Proper division of the water, in the absence of any great inecpiality in the resistances of the branches from the exhaust steam main, insures that each heater will take its proper sup])ly of steam and heat the water to a temperature corresponding to the back pressure. The water can be drawn from heaters operated in parallel in this manner by a single boiler feed pump. The admission of cold or make-up water is regulated by a float-box, which is con- nected to the water spaces of both heaters by an equalizing pipe and to the steam spaces by a similar pipe. This arrange- ment permits of additions to the plant merely by connecting in additional heaters, and any individual heater may be cut out of circuit for cleaning (^r inspection Ijy closing the valves in the respective separator and trap. With the steam-stack arrangement this gives the plant the benefit of the total sepa- 1 1 rator capacity at all times. The multiple unit arrangement is especially convenient in connection with softening systems. In plants of any considerable size it is better to install two Sorge-Cochrane Systems according to the multiple unit ar- rangement than to install one large softening system, since the multiple arrangement makes it possible to clean the filter of 43 If COCHRANE HEATING ENCYCLOPEDIA Boiuri' FfTCD CochraJie Steam-Stack and Cut-Ovt Valve Metering Heaters arranged as a Double Unit. The returns from the condenser are first measured in a Cochrane Metering Hot Well, which automatically ad?nits the required ainount of make- up water and then divides the water equally between the two heaters. 44 % I 1 1 HEATER SPECIFICATIONS one while the other continues to lieat and soften the entire boiler feed supply. The use of this arrangement overcomes all troubles formerly experienced with heaters in multiple, as for instance the unequal division of the water, not heating the water in one heater as hot as in the other, etc. Our Engineering Department is prepared to suggest new and special arrangements in connection with exhaust steam piping, feed-water heaters, oil separators, etc. SPECIFICATIONS FOR HEATERS AND RECEIVERS TO BE USED IN CONNECTION WITH EX- HAUST STEAM HEATING OR DRYING SYSTEMS In drawing specifications for an exhaust steam heating or drying system it is well, since most of the heaters now on the market are improperly designed or insufficiently equipped in some important particular, to define by clear and unambiguous clauses the essential and important features which the heater and receiver should possess. AVe offer the following as being impartial and fair and in the interests of the purchaser. While these specifications do not go into the details of construction except where such details are essential, \\\(t\ will serve to protect the purchaser in some measure from being imposed upon as to size and capacity, or from being supplied with imperfect piping arrangements or defective heaters. SPECIFICATIONS FOE HEATEB AND RECEIVER WITH PROYISION FOR PURIFYING THE SUR- PLUS EXHAUST STEAM PASSING TO THE HEAT- ING SYSTE.V. The Iteatcr is io have ample eajiacHij for lienhiii/ ilie iratcr reejuired fejr IT. P. ejf Boilers, ineluding snrli over- load as mail he carried on the boilers, taking the initial supply at 60 degrees F. and delivering it at a temperature iviiliin from 2 to 5 degrees of tJie temperature of tJie steam entering tlie liemler, u-Jien the tieate?- is kept filled iritlr steam. Tlic heater is to have a ivater .storage capacity heloiv overfloiv level of not less than cu. ft. ]Yith the heater is io he f'Urnislied an oil separator of approred design (self-cleaning type) and of ample capacity for purifying e.rhaust steam to an amount 45 COCHRANE HEATING ENCYCLOPEDIA i'(/iii raJriit io flir fall ml I'll III purl 1 1/ oj III!' Iii'iili'r. iiiinichj lloilrr II. ]'. Also, siirli Inij: III- Iri'ljis lis iiiii\ III' iirii'ssiii'il for il niiiiuii/ till' oil sc fill ralor and Inl'- I III/ riirr of tlir iiri'r- /ioir frmii llir linilrr. Ilic riiirr iiri'ii of Hie Ini/i In III' mil li'ss lliiiii llir full iiri'ii of ihiji jiijii' from llii' si'jiiirnlor. Hint IS. till' iiri'ii of till' riilrr in llir struni tin ji IS III III' not less Itiiiii tlie urea uf a iarti jiijie. Till' tiealer is to lie a aiiitanj slrar- tan' i-iiai jirisini/ a tiraler iiait sr jiiiralor. aait iiienns for eon I roll 1 111/ ttie juissaiji' of sli'iiiii helireen ttie sejiaratoi- anil Hie tiealer. all su arranijeil Unit till' lii'iili'r ran he isotaleit or rat nff. fur r.rii ni ilia I ion or rlranini/. frmii till' jiatti of steam to Hie tiratiiiij si/sfem nr to at iiinsjitierr. Ttie separator is Io roninii'e ui operalmn irtieri Hie tiealer is cat oat. at irtiirli times Hie itrainaije nf Hie separainr is to rontiiiar I nilr prnilnitl 1/ nf llir orrrftoir itriii iiiii/e. 'J'lie tiriitrr is titenrise Io lie prornteit iritti reinhli/ rr morahle rast-irnn trai/s. rolil irati'r rnj nial inij ralre unit float for rontroll- iiiij till' lilt III issioii of Hie rolit irater sappli/ iimter a jiressare on till' roll! initrr snpjili/ line of from 10 Io SO lbs. Sailatile pro- risioii Is also to he iiiaili' so Hint filtmnij or ile posit ine/ inalrrial mill/ lie rarni'it iritlnn the tienler luuter iloirn ira nt fl Ira I Ion . I'ain/i sa/i/iti/ is In he liniiitnl anil rrnteit to steam spair. ('orliraiii'Sti'iiiiiSliicI: unit < 'iil-Oiil \'iitn' Ih'iilrr llislittlril III mil lli'i'linil iriifl r.fllil list .sUil III hrlttlllf/ plillll ill II llil/ll si'tlnnt hllilililll}. 46 COMMERCIAL SYSTEMS COMMERCIAL SYSTEMS OF EXHAUST STEAM HEATING AND HOW THEY ARE SIMPLIFIED AND IMPROVED BY THE INTRODUCTION OF THE COCHRANE STEAM-STACK AND CUT-OUT VALVE HEATER AND THE COCHRANE MULTIPORT BACK PRES- SURE VALVE In the following pages are presented the essential details of the leading exhaust steam heating systems arranged alpha- beticall_y for convenience. In each case it is shown that money may be saved and better results secured, and moreover a much greater degree of safety assured, by the use of the Cochrane Steam-Stack and Cut-Out Valve Heater and Receiver and of the Multiport Back Pressure Valve. In fact this Cochrane ecjuip- ment is now accepted by most of the leading heating engineers of the country as standard. One of the foremost makers of vacuum heating systems listed in the following pages states, in regard to specif j'ing our equipment: ''In making our plans, we of course adhere closely to the ideas of either architect or owner, but in every case, where our , opinion is asked, we most decidedly advise the purchase of a Cochrane." Another prominent New York manufacturer of heating systems writes: "We are continually recommending your heater to people in our line and feel sure the application of your goods to our system will give every satisfaction to the user." ESSENTIAL ELEMENTS OF AN EXHAUST STEAM HEATING OR DRYING SYSTEM A heating system is the arrangement of apparatus by means of which steam is taken from some source, as a steam boiler or the exhaust pipe of an engine or turbine, and circulated through radiators, together with means for removing the water of condensation and the non-condensable gases or vapors, and in most cases for returning the water for further use in the boilers. The following elements may be considered as prac- tically essential: 47 COCHRANE HEATING ENCYCLOPEDIA ~ro ATr^OSPHtRL How On: laijoul illmsliiilcd on pinjr Id run he improved hi/ tin' use of the Cochrane Stearn-i'^iiwl- ami Cnt-Out Witvc Heater and Hi-. 7. Escape of Air from the Radiators. This is neces- sary not only because the radiators are normally full of air when the system is first started, but also l:)ecause a certain amount of air or other non-condensable vapors is sure to be brought into the radiators by the exhaust steam itself, a small amount of such gases almost invariably being pumped into the boiler either as originally dissolved in the feed water or due to the drawing in of air around the plungers of boiler feed pumps. The installation of a Cochrane Open Feed Water Heater, in which the water is first purified by spraying through an open steam bath, greatly diminishes the amount of air to be handled, which is beneficial both as regards the action of radiators, and also as diminishing the tendency to corrosion throughout the interior of the system. However, even a very small amount of air, by continual accumulation, would final!}' air-log the radiators, unless some means were adopted for its removal. Where parts of the system are operated under vacuum, the possibility of air infiltration through leaks in the piping will he evident. If back pressure is to be maintained upon all parts of the system, air may be discharged through small valves attached to the radiators, either controlled by hand or thermostatically. Unless the discharge from these valves is conducted away bj^ a piping system, the vapors are apt to prove objectionable, because of accompanying odors and moisture. The piping system 51 COCHRANE HEATING ENCYCLOPEDIA 52 COMMERCIAL SYSTEMS may he the return main for the water of contlensation, or an entirely independent air piping system may be in- stalled. In either case, but especially in the latter, means tor producing vacuum in tlie air-removal system are usually employed, and in order to prevent the flow of steam directly through the radiators into the vacuum piping system, a therniostatically-controlletl valve, or in some cases a seal which permits of the free escape of water, l)ut prevents the escajie of air or steam except through a small jjin-hole, is employed. 8. A Receiver or Returns Tank for the collection and storage of returns is usually provided, particularlj^ if they are to be pumped back into the boiler. This receiver should be of sufficient capacity not onlj- to take care of tlie irregular flushes incidental to the operation of a heating system, but should also be provided with overflow to the sewer or elsewhere. The most useful form is the Cochrane Heater and Receiver, which not only provides for the storage of the water, Init also for its heating to the full temperature of the exhaust steam before it is pumped into the boiler. The Cochrane Heater and Receiver is provided with a trap-controlled overflow for the discharge of excess water, and is also fitted with a Cochrane Oil Separator to purify the exhaust steam consumed in heating the water. In the Cochrane Steam-Stack and Cut-Out \'alve Heater and Receiver, this separator is made large enough to purify all of tlie exhaust steam, replacing the independent separator and trap called for under (f), as explained fully in preceding pages. 9. M.\ke-up Water Regulator. In a heating system in which the water is used in a cycle, ]xissing successively through the boiler, the engine, the heating system, the heater and receiver, and back to the boiler, there are nearlj- always losses due to escape of steam through the back pressure valve, leakage, use of hot water for other purposes, etc., which must be made up by the injection of fresh water into the cycle. In the Cochrane Heater and R,eceiver this is looked after auto- matically by means of a float in the storage chamber, which controls a regulating valve in the connection to the city water- mains or other source of make-up water. The cold water thus admitted is delivered into the cold water box, and in falling 53 COCHRANE HEATING ENCYCLOPEDIA VCWT 'p^ t= J Waste To Sewer m ^ w ■%# |i;-',--7<.r-^-,> \ i ExMAU3T From ( * ' ' "' ' ENOiNta. Pumps. &C. Q pCMRANE * ^ Steam_Stack Heater Vac. Pump Tlu: Crcscoil system of exhaust slidm hraling ns itisl2 wl 80 COMMERCIAL SYSTEMS is self cle:uT.ing. The JMorgan-Clark Vaeuum Valve is always used in connection with a ]\Iorgan-Clark Controller located at proper points in each riser. This regulates the vacuum, so that there is no short-circuiting of steam circulation in radiators or coils nearest the vacuum pump, therel^y allowing those at a distance to become cold. Operatively connected to the heating system is a blow-off or flushing system. Should the valves become clogged by scale or any other cause the Vacuum System may be shut off and steam pressure turned on, which overcomes the tension on the adjusting spring of the valve and all de- posits may be blown into the sewer without trouble. When using steam properly purified of oil, dirt, water, etc.. as from the extra large oil separator on every Cochrane Steam-Stack Heater, provision for flushing the system is not so essential. Page SO shows a typical layout of this system with a Coch- rane Heater and INIultiport \'alve. THE PAUL VACUUM SYSTEM Page 82 shows the Cochrane Steam-Stack and Cut-Out Valve Heater and Receiver installed in connection with this system. This is a one-pipe air line arrangement in which the removal of air from the radiators is accomplished by air valves of the expansible plug type connected with air lines leading to some form of pump or ejector. This system handles the air alone, the condensation flowing back to the heater l)y gravity. A special duplex vacuum pump, ecpiipped with an electric motor, is made for use witli this system. This pump is also provided with an automatic air suction, which eliminates air binding and pounding, and which operates onlj^ when there is air to be removed from the radiators. The system may also be fitted with a Paul double or single exhauster, or hydraulic exhauster. The original Paul system patents having expired, air line systems of this type are coming into witle use, various manu- facturers having devised special apparatus for producing the vacuum. POSITIVE DIFFERENTIAL SYSTEM The Positive Difl'erential system of exhaust steam heating, page 84, consists of the following essential parts: 1st, a throttling valve for admitting the desired amount of exhaust 81 COCHRANE HEATING ENCYCLOPEDIA n To Atmosphere % - The Paul viictiniii xi/slcm af xlniiii liidtiini. iritli ('nrlira kc .S7<7i//(-.S7((c/,- and Cut-Out ValiT llrnlir iirrfiiniiiiiij Ihc (iiiicliinix nf fi'iil-iniU:r liciitrr, return tank, inilepcmlcnt oil scpanilur and trail, raw water regulator, etc. 82 COCHRANE EXHAUST STEAM HEATING steam to the radiators: 2(1, an automatic impulse valve on the outlet of each radiator, and 3d, a positive differential valve located in each return riser for maintaining a standard differ- ence in pressure between the steam supply and return risers. For instance, the engine may l)e exhausting under |-lb. back pressure, which would be the pressure in the steam supply riser, and in the radiators when turned on full; the valve at the outlet of the radiator would be set at ^-Ib. to reduce the steam pressure to zero, while allowing the discharge of water by gravity through the valve. The differential valves in the branch return will be weighted with al^out 5 lbs. to the sq. in. area of seat, which permits a vacuum of about 10 inches to be built u]5 in the return main. K js If the vacuum should exceed this amount, steam would # J pass through to the pump, nullifying the action of the latter, \ I since injection water is not employed. Tlie amount of steam ^ I drawn through the valves at the outlets (jf the radiators I I is then the quantity that is just sufficient to supply the radiat- / ''' ing effect of the return mains. It is claimed for this svstem / I that exhaust steam or live steam, or the two mixed, can be cir- ' I culated at a pressure at the point of supply not greater than '', I that due to exhausting directly to the atmosphere through an ' ^ open exhaust pipe, and that when the exhaust steam available exceeds the heating requirements, it may be circulated with the ^ back pressure valve wide open, and that any desired amount of vacuum may be carried in the return mains without jet / water at the vacuum pump. ^/ RELIABLE VACUUM SYSTEM ' ^ Page 85 shows the application of the Cochrane Steam- \\ Stack and Cut-Out Valve Heater and Receiver to the "Re- ' t liable" Vacuum System. This system is usually installed on / J the one pipe plan and consists of an air suction or vacuum i I pump and a condenser located in the Ijasement and connected $ I by means of an air pipe to automatic air valves on the radiators. ^ i These air valves permit air to be drawn from the radiator by the pump, but close to steam. The condenser prevents steam, water and foreign matter from entering tlie pump, enabling the pump to operate under constant conditions, notlung but air ever passing through it. The Reliable vacuum pump is made in two types, one operated by city water pressure, the 83 i f COCHRANE HEATING ENCYCLOPEDIA To Atmosphere: IriPULSE Check Valve: Cochrane: ^ Steam Stack Heatcr 'I'lisilirr l>iflrrr,iliiil" !nl \'olre Ihulir (i/iil h'crcirrr. 88 COMMERCIAL SYSTEMS automatically closes the steam valve and opens the water valve, admittina; a water spra>' to tank and tliermostat. This produces a vacuum which draws in the air. The thermostatic valve, cooled l)y the water, will then close, sluitting otf the water. When all the air in the s>'stem is exhausted the inten- sity of the vat'uum in the tank, operating on a diaphragm, kicks the vah'c mecliauisni with all valves closed until the vacuum drops to the minimum point at which the pump is adjusted. Just as soon as tliis point is reached, steam is again admitted and the operation is repeated. THE SURE SEAL SYSTEM The Sure Seal ^'acuum System, on page 92, is pipcfl in a manner similar to that of the ordinary gravity return system, except that at the outlet from each radiator is placed an auto- matic water seal, wliich while allowing the escape of condensa- tion, retains enough water to seal the passage against steam. The constant withdrawal (if air is provided for l;iy a small vent above the water level. A vacuum i)umi) may he used with this system to hantUe the air and cond(aisati(jn, or tlic "Sure Seal" vacuum generator may be employed. The latter is a special kind of return traj), the returns being discharged from it by live steam pressure. When tlie water has lieen ex- pelled, the supply of steam is shut off and the condensati(.in of the steam in the trap creates a vacuum, which serves to draw the returns and air from the heating system. The installation shown on page 92 will o]3erate with exhaust steam and dis- charge into the heater or with live steam taken from the boiler through a pressure-reducing valve, tlie condensation being returned directly back to the Ixjiler through the Sure Seal vacuum generator in the boiler room. THE THERMOGRADE SYSTEM The Thermograde semi-automatic svstem of exhaust steam heating, page 93, is piped substantially as the ordinary two-pipe gravity return system, excepting that the return part of the system is vented to the atmosphere. The admission of steam to the radiators is controlled by special supply or modu- lation valves, which can be adjusted to heat the radiator whdlly or partially as desired. With a given difference of ])r(\ssure between the supply pipe and the radiator, a definite amount 89 COCHRANE HEATING ENCYCLOPEDIA AirRiser Exhaust to Atmos pmcrk ^CHRANE Back Pressure Exhaust From Engines, PuMFS,,fec, ^CHRANE Steam Stack Heater E.i-h in cti/i- nciitnn iriOi the Cochriinc Shu tii-ShirJ; ii/id Ci/l-Ou{ ]'(!lvc Ilaiirr engine, and over 70% of the original heat of the steam will be thrown away in the condenser circulating water. f One pouiiu oi steam used first in che engine and * then in the heating system will therefore replace about ^ \\ pounds of steani required where the engine is run con- / densing and live steam is used in the heating system. /, If it is necessary to decide between running non-condensing / the year around and using exhaust steam for heating, or run- ning condensing the year around and using live steam for heating, the relative sizes of the heating and power loads and the length of the heating season should be taken into considera- tion. For instance if the heating load is 7.5% of the ]50wcr load and the heating season is six months, a 100 H. P. non- condensing engine and exhaust steam heating system running 10 hours per day and 300 days per year will, at 28 lbs. per H. P. hour, consume 8,400,000 lbs. of steam. An engine running I condensing the year around on 21 lbs. of steam per hour and a I heating system using live steam at 75%, of the rate of the non- I condensing engine for six months will consume 10,500,000 I pounds of steam per year. The extra cost and expense of the condenser and auxiliaries in the latter case will much more : than counterbalance the larger radiators and special piping 109 COCHRANE HEATING ENCYCLOPEDIA 110 CONDENSING SYSTEMS system used with exhaust steam. In general it may be said that where on the average 25% or more of the exhaust steam can l)e utilized for heating it will be more economical to heat with the exhaust of the engine than to use live steam for heat- ing and run the engine condensing. Obviously in many cases, and especially where the power load is large in comparison with the heating load, the best ar- rangement will be a combined system. We may note five classes of plants: (a) Those in which all of the exhaust of the engine can be utilized for heating during the heating season, in which case it will pay to shut down the condenser and use the exhaust steam for heating when required. If only part of the exhaust is needed for heating, say less than one-half, the following courses are open: (b) If there are two or more engines, one or more can be run condensing, and the other can exhaust into the heating system during the heating season. (c) The engine can be so arranged that one end of the cylinder will exhaust into the feed water heater and the heating system, while the other end is run condensing. (cl) With a double engine one cylinder can be run condens- ing and the other non-condensing. (e) If compound engines are installed, as they should be for running condensing, steam can be withdrawn for heating from the intermediate receiver of the engine, which can take the form of a Cochrane Steam-Stack Heater. Thus as much steam as is required for heating is taken from the engine after it has already done nearly as much work as it is capable of doing in the engine, while the remaining steam is allowed to expand in a low pressure cylinder, and to exhaust to the con- denser. To insure sufficient steam for heating, while preventing waste, and to equalize the load on the two cylinders, the point of cut-off of the low pressure cylinder should be controlled by the pressure in the receiver, using a receiver pressure regulator. (i) The reciprocating engines can exhaust at about atmos- pheric pressure into the Cochrane Steam-Stack Heater and Receiver and the surplus steam, after it has been relieved of en- trained water and oil by the separator, can be used partly in the heating system and partly in a low pressure turbine. The 111 COCHRANE HEATrNG ENCYCLOPEDIA 112 CONDENSING SYSTEMS efficiency of the engine-turbine set will in general be much higher than that of a compound engine rimning condensing. AVhen the heating system is not in service, the turl)ine will take all of the exhaust, or when there is insufficient exhaust for the heating system, the turbine itself can receive live steam and exhaust against back pressure. (g) A variation of the above can be applied in all-turbine plants, where two turbines can be arranged in series, part of the exhaust from the first being applied to heating, and the remaintler expanded through the second to the condenser. The first use for the exhaust steam should be to heat the feed water, since all of the heat of the exhaust steam so utilized is returned undiminished to the boiler. A Cochrane Steam-Stack Heater placed between the engine and heating system in any of the above cases will serve not only to heat the boiler feed water to 210° F., but will also act as a hot well for all return drips and condensate, and the extra large separator attached to the heater will serve both to prevent cylinder oil from entering the heating system, and to supply dry steam to the low pressure cjdinder or low pressure turbine of condens- ing outfits. Because of the large volume of the heater, con- sidered as a receiver, ideal results will be obtained from a compound engine. The arrangement suggested under (f) is illustrated on pages 112 and 114, in which mixed flow turbines for increasing the capacity and improving tiie economy of reciprocating engines are shown in connection with exhaust steam heating systems. On page 112 the turbine is so connected that it may receive either surplus exhaust steam from the engine, discharging to a condenser, or when the heating require- ments are severe it can receive live steam, discharging into the exhaust steam heating system. It may also be operated upon live steam condensing when the engine is shut down, in which case the boiler feed water will be heated in the Cochrane Heater by exhaust from the auxiliaries. The arrangement described under (g) is really the same, except that both main units are turljines. This equipment gives a maximum over-all efficiency at all times, and nearly or ciuite twice as much power is developed from a given amount of fuel during the Summer as would be possible with an engine alone. 113 COCHRANE HEATING ENCYCLOPEDIA = 2; e 114 LOW PRESSURE TURBINES Wherever a mixed flow turliiiie is used, it is advisable to install an automatic flow valve between the low pressure inlet to the turbine and the engine exhaust piiMng, in ortler to prevent vacuum backing up into the exhaust piping and drawing in air through leaks and through tlie j^iston rod and valve-stem packings of the engine. Such air would be extremely UTifavor- al)le to a gooil vacmim in the condenser. On page 143 is shown an excellent valve for this purpose, so arranged that whenever the pressure in the exhaust pipe falls to a certain jirede- termined pressure, as 1 lb. or J lb. aliove atmosphere, the valve closes and remains closed until the pressure in the exhaust line again rises above this point. (h) In some plants the demands for ])ower are so great in comparison with the tlemantls for steam for heating that the total amount of steam for the latter use will always be less than the amount of steam which must be produced for power purposes. In this case the most advantageous arrangement is that shown on page 110, where the exhaust from the auxiliaries serves first to heat the feed water in a Cochrane Steam-Stack and Cut-Out Valve Heater and Receiver, and then passes to the exhaust steam heating system. If the amount of steam rec|uire(l for heating pur]ioses is greater than the aux- iliaries can supplj' at all times, it will be advantageous to draw off a supplementarj^ supply of steam from an intermediate stage of the main turbine, which will be of the bleeder type. If, on the other hand, this is not required, l)ut it is desired to utilize the surplus exhaust steam during the summer time when it is not needed for heating, the main turl>ine may l:)e of the mixed flow tjqoe, receiving the surplus after it has been purified of oil in the separator attached to the feed-water heater. THE COCHRANE STEAM-STACK HEATER IN CONNECTION WITH LOW PRESSURE "URBINES A low pressure turbine of moderate size receiving exhaust steam at atmospheric pressure and exhausting into a gootl vacuum will produce a H. P. -hour on a consumption of 30 lbs. of steam. In other words, the power output of a non-condens- ing engine can be about douljled by installing a turbine and condenser, but without adding to the coal consumption or to the number of boilers. There are also many isolated ])lants 115 COCHRANE HEATING ENCYCLOPEDIA I f y u <\ c > r 1 T < o 3 CL u 3q m 116 LOW PRESSURE TURBINES where more power is needed but where room is laclving for the further extension of the boiler phmt ainl wliere therefore the installation of a low pressure turlhne is the only alternative to tlie purchase of power from outsitle sources. The steam exhausted by a reciprocatino- engine is supplied intermittently, and is laden with considerable cjuantities of oil and water, while steam for a turbine should be received con- tinuously, and should be free of liquid particles, since the latter will cause erosion of the blades and increase the steam consumption of the turbine, while oil in the steam unfits the condensate for use as boiler feed. For such installations, we recommend our Steam-Stack Heater and Receiver, which per- forms the functions of an intermediate receiver, steam separa- tor, feed-water heater and hot well. By bringing all the feed water up to boiling point, it will moreover increase the capacity of the boilers so that the total power producing capacity of the plant may be more than doubled. The substitution of pure distilled water as boiler feed in place of a former supply of scale-forming water may also further increase the steaming capacity and reduce operating costs. This heater can con- veniently be arranged to supply purified exhaust steam both to an exhaust steam heating system and to a low pressure tur- bine. Usually the heaviest heating load occurs in the morning and the heaviest lighting load in the afternoon, so that the two do not conflict, but if the combined demands of the turbine and of tlie heating system should at any time exceed the ex- haust steam output of the engine, live steam can be admitted temporarily through a pressure reducing valve from the Ijoilers, or a mixed flow turbine, in which the exhaust steam is auto- matically supiilemented with live steam as rec}uired, may be installed. Page 114 shows a Cochrane Steam-Stack Heater installed in a plant of this character. Where satisfactory feed-water heating arrangements are al- ready installed, the combined muffle tank and oil separator shown on page 1.32 is recommended. 117 COCHRANE HEATING ENCYCLOPEDIA ^^ Hlp>% '*»»'f**7 i*Jy .t^J^ d^ "■■'^ S'^V'1 118 ICE AND REFRIGERATING PLANTS COCHRANE STEAM-STACK HEATERS IN ICE AND REFRIGERATING PLANTS COMPRESSION SYSTEMS The Cochrane Open Heater is peculiarly well adapted for heating boiler feetl water in ice and refrigerating plants, because of the fact that it eliminates from the water a large percentage of the air and gases, including not only those held in solution, but also those in chemical combination in carbonates and organic compounds, so that these gases do not reappear in the steam, or in the water condensed therefrom for ice making purposes. Foul gases produced by the decomposition of organic matter in l.ioiler feed water sometimes are the cause of an un- pleasant taste in the distilled water. Unless removed from the water before it is put into the boilers, these gases distill over with the steam into tlie engine, and appear in the water again in tile exhaust steam condenser, necessitating prolonged and vigorous reboiling for their removal, so that in s(nne plants as much as 1(K"J^ of all the live steam produced is recpiired for the reboiler. As will be evident, the driving off of these gases from the water liefore the latter enters the Ijoilers will relieve thcreljoiler of much of this work, while its efficiencj' for remov- ing air and gases and unpleasant odors and tastes will lie aug- mented. This is of especial importance in the case of can ice. The open heater also serves as hot well or receptacle for drips from live steam mains, condensation from reboilers, cooling water from ammonia and steam condensers, condensation from the generators of absorption refrigerating machines, etc. The suitability of water from an open heater for boiler use is contingent upon the perfect removal of cylinder oil from the exhaust steam. To lie at all permissible, an open heater must be protected b}' an effective oil separator. The extra large separator attached to and forming, a part of the Cochrane Steam-Stack Heater takes care of all of the exhaust (doing away with the need for an independent separator) and thereby serves not only to keep oil out of the feed water, but also to purify of oil the exhaust steam going to tlie atmospheric con- denser. See page 116. In some cases, objection is made to the arrangement above suggested that the heater may take exhaust steam which is required in the condenser, and would otherwise be condensed 119 li COCHRANE HEATING ENCYCLOPEDIA '^' K^ '~~ 1 1 1 1 ^'^r^^a^- 120 ICE AND REFRIGERATING PLANTS there. To meet such conditions, we have devised an ar- rangement wherein the steam passes first through a Cochrane Oil Separator into the condenser, any surplus escaping through a Cochrane Multiport Exhaust Relief Valve to the heater. The heater thus receives and utilizes steam which would otherwise be wasted, and shows a corresponding gain for those periods when all the steam, for one reason or another, is not condensed in the atmospheric condenser. ABSORPTION SYSTEMS Where an absorption system is operated in connection with a compression system, or in connection with a ])ower plant, the exhaust steam from the compressor or other engine Ijeing used under a back pressure of 10 pounds or more in the generator of the absorption system, a Cochrane Steam- Stack Heater of the receiver type should be placed between the engine and the generator. The heater will then serve to heat and purify the l)oiler feed water, and will also act as a recep- tacle for all drips and other suitable hot water about the plant, while the oil separator on the heater will prevent oil in the engine exhaust from entering the steam coils of the generator or the steam condenser. At the same time, the valve in the vent pipe of the heater can be kept slightly open to permit of the escape of air and gases to the atmosphere without wasting any appre- ciable amount of steam, so that the steam after condensation in the generator will be entirely suitable for ice making. Com- bination systems of this kind are able to produce 12 to 14 tons of ice per ton of coal burned, while at the same time the engine can be of an inexpensive and substantial type. See page 118. In compression, absorption, and combination compression and absorption plants, the Cochrane Steam-Stack Heater takes care of all surplus exhaust steam about the plant, as well as hot drips, without regard to the ciuantit}'. The pumps, for instance, may produce either more or less steam than is re- cjuired for heating the boiler feed water. If more, the excess, already purified of oil, will be available for making ice; if less, it will be supplemented by the engine exhaust. There is no waste. In plants where the exhaust steam is used largely for heating in the winter and for ice making or refrigerating in the summer, the Steam-Stack Heater serves the ]iurpose of l)oth systems most conveniently. 121 if COCHRANE HEATING ENCYCLOPEDIA The heater shown on page 120 is installed in an al:)soi'])tion refrigerating plant, where it reeeives the exhaust of pumps and other auxiliaries under baek pressure, the shell being cast in one piece and the lieads being lieavily stayed to witiistand a pressure of 40 lbs. In thc^top of the heater is a pipe oi)ening for vacuum ]iump returns, in atldition to the usual vent and traj) discharge openings. 122 FEED-WATER METERS MEASURING THE BOILER FEED WATER In large steam plants, such as central stations, economy of operation usually receives the scrutinizing attention of experts, but in isolated plants, such as those in which exhaust steam heating is employed, the possibilities for improving economy are often not so keenly searched out, with the result that many plants of this character are not showing as good results as they should. The test of whether or not a steam plant is being run properly is the amount of water evaporated, since by com- paring this quantity with the amount of fuel consumed, the efficiency of the boiler and furnace can be determined, and by comparing it with the wattmeter readings, the average efficiency of the prime movers is shown. In other words, a reliable feed-water meter is as essential to the economical operation of a steam power plant as is a cash register or ecjuiva- lent device in a retail business, or a time-clock in a manufactur- ing establishment. It is a measure of what is received in re- turn for the money expended for fuel. Among the advantages of keeping an accurate record of the amount of water fed to the boilers may be mentioned: Determining the boiler efficiency, that is, the number of heat units recovered per pound of coal. Determining which grade or kind of coal is the most profitable for use in the plant. Determining which method of firing is best or which firemen employ the most efficient methods. Detecting when the boiler settings and grates, etc., need attention for the stopping up of leaks, etc. Determining the difference in the efficiency of the boiler heating surface when clean and when coated with scale or soot. The presence of a feed-water meter exercises a valuable moral influence upon the operating force, not perhaps to be determined in percentages or in dollars and cents, but nevertheless a real and effective aid towards increasing economy and profits. Numerous hot water meters have been proposed in the past, but have not met with acceptance, because of various defects. Displacement meters soon wear out and become 123 COCHRANE HEATING ENCYCLOPEDIA I s 1 1 1 1 i i S f ^ si i i I .^ii 11 124 FEED-WATER METERS Manner of Ajt/jlying the V-Notch to Metering Hoi Boiler Feed Wilier in the Cochrane Metering Healer (Palenleii) inaccurate. Meters of the Pitot tube or constricted tube types are not satisfactory in feed lines supplied by reciprocating pumps, nor are thej' even passably accurate at fractional loads. The volumetric or dumping type of meter is very bulliy in large sizes, and is subject to deterioration through the accumulation of sludge and scale, and is not suitable for operation with back pressure as found in exhaust steam heating and drying plants, that is, if fed with water at a temperature above 212 deg. F. , part of the water at once evaporates, causing a nuisance by reason of the vapor produced, while tlie heat represented bjr the drop in temperature, 1% of the fuel value for each 10 deg. F., is lost. The Cochrane Metering Heater employs as the measuring device the V-notch weir, which repeated investigations, carried out with the greatest precision, have shown to possess an ac- curacy within J of 1%. The settling chamber of the heater is 125 COCHRANE HEATING ENCYCLOPEDIA if 1 1 5^ « i C'X HIMNi '^'' ■ ViO^it HI ^li' Cochrane Metering Heater {Combined Open Feeel-Water Heater and Meier fitted 'mith Steam-Staek and Cat-Out Value, for use with exhaust stearn healing system. (Patented). 126 ,i FEED WATER METERS ^ utilized as the still water or approach chamber for the weir, ami I as the latter is enclosed within the heater structure, there is no annoyance from the escape of vapor, nor loss of heat, and the water may lie metered at any temperature corresponding to the hack pressure. Since there are no moving parts in contact with the flowing water, the durability of the device is great, and accuracy is maintained. The Cochrane Metering Heater is built both in the usual rectangular type, see page 126, also in the horizontal cylin- drical type, for use where headroom is limited and where an exceptionally large water storage capacity is desired in the outflow chamber to take care of flushes of returns. Plants in which open heaters are already installed can Ije ecpiipped with meters, under our patents, bj' installing an in- dependent weir chamber with suitable water connections and equalizing connections leading back to the heater. Where closed heaters are in use, we recommend our Metering Hot Well, which besides serving to measure the feed water, ;dso acts as a hot well or receiver for condensate, and as an auto- matic make-up water regulator. If the closed heater is \)xo- tected by an oil separator, the condensate may l)e led to the metering hot well, thus giving most of the advantages, except compactness, that would he obtained by the installation of a Cochrane Metering Open Feed Water Heater and Receiver. The recording instrument used with the Cochrane Meters is a simple mechanical device producing uniform coorilinate charts which are easily integrated liy means of an ordinary planimeter, as used on engine indicator cards. W'e also supjily automatic integrators, by means of which the total water passed in a given time may be read off at once without planimetering. The Cochrane Meter has the further advantage over any mere counting mechanism in that the record chart shows at a glance the exact load for every instant throughout the day, that is, a history of the operation of the plant is preserved, from which irregularities, the beginnings and end- ings of heavy demands for steam, etc., are clearly perceptible. 127 COCHRANE HEATING ENCYCLOPEDIA Siiroc-CiH-lininc Hnl I'mirxs Snflciniio •' ins(ilul)le, and into carlxju dioxide gas, whicli escapes from the heater through the vent inp(>. At the same time air and other gase.s are driven off, and as air has lieen shown to be an essential 128 SOFTENING BOILER FEED WATER Sorge-Cochrane Hot Process Wntrr Soflmliig System fitted with Stenin-Slnck for si/rplus ij-lniusl. The roir irriter is kepi r//«;;7 froiri the niniliiised returns unlit iifler trentiiiinl . conilitionto corrosiun l)y feed water, the water is rendered non- corrosive at the same time that it is rendered ncjn-scale-forming. Where the raw make-up water contains sulphates, chlorides or acids, the addition of a softening chemical is necessary in order to protect the boilers against scale and corrosion. The Sorge-Cochrane Hot Process Water Softening System, while performing all the functions of the Cochrane Open Feed-Water Heater, provides in addition for the automatic feeding of the necessary chemical reagent, and for the proper settlement and removal of the resulting precipitates from the water b}- filtra- tion. With this system, results superior to those obtainable with cold process systems can be guaranteed, because: 1. The water is treated hot, and chemical reactions are more rapid and complete in hot water than in cold. 2. The resulting precipitates are larger and heavier in hot water, and settle more rapidly than in cold water, hence more perfect separation of the precipitates with a given capacity of settling tank. 129 COCHRANE HEATING ENCYCLOPEDIA 3. The monofai'ljoiiates re^'ultiiig from the transformation of ehloridcR ami sulphates are less solul)le in hot water than in cohl wat(>r, hence less remain in solution in water treated in a Sorge-Cochrane Hot Pi'ocess System than in water treate(l in a cold ]irocess s_ystem. The truth of the foregoing statements will be granted by an>'onc who has had occasi(jn to i)ass water from an ordinarj' cold ])rocess softening system through a feed-water heater. Although tlie water may be perfectly clear when it leaves the cold iirocess system, there is invariably a heavy deposit of scale and sludge in the heater, due to the further chemical action which takes place wlien the water is lieate(l. In the Sorge-C'ochrane Hot Process System the water is heated Ix'forc it is treated chemically, which has the advantage not only of making the treatment more rapid and perfect, but also of driving off air and gases lield in solution in the water. The S(jrge-(_'ochrane System jjermits of heating and chemically treating the raw make-up water while only heating the condensed returns, all in the same apparatus. It is always preferable to treat the raw make-up water before it has become mixed with the condensed returns, since the chemical reactions are moii' ])ronipt and complete in concenti-ated solutions than in dilute solutions. In plants where floor space is limite(l, or where the capacity, or the amount of incrustants in the water, is large, we recom- mend oiu- vertical hot ]>roccss systems, which occupy much less space and offer special facilities for cleaning, pi'actically all of the ])recipitate and sludge being removed liy the sim])le ojiening of a sludge valve. As regards the steam end, the Sorg(>-( 'ochrane Hot Process S>'stem ma>' take any of the forms of the standard Cochrane Heater, including tlie Steam-Stack and Cut-Out ^'ah-e Heater and lieceiver and the Cochrane Metering Heater. UTILIZING EXISTING APPARATUS FOR A SOFTENING SYSTEM Where Cochrane heaters are already installed they can, in many cases, and with only a few (dianges, be made part of a Sorge-Cochrane Hot Process Softening System, savino- some of the cost, and at the same time securing all the advantaoes in the way of automatic o])(>ration, large settlement and 130 STEAM AND OIL SEPARATORS filtration capacity and continuous sujijily of hot softened water to the boik-rs jiossessed by the standai'd system. Cochrnne Hnrizoidnl Oil Sepnralur, Working FicKsiire, -50 lbs. per sq. in. or le.i.-i. SiTvice, non-condensiitg Siclion of ('oclrraiie ImUpfn- drnl Scpnrntur, parallel a-ilh bajfli: COCHRANE INDEPENDENT SEPARATORS The installation of a Steam-Stack and Cut-Out Valve Heater generalh' renders an indejiendent oil separator super- fluous. However, it is sometimes necessary to purify exhaust steam for closed heaters, or steam going to open heaters not equipped with efficient oil separators, or the steam passing to the heating or drying system where the old style heaters and receivers are already installed, or where a hot well or return pump is employed instead of a heater and receiver, or where it is more convenient or cheap(>r to run directly to the heating system from the engine than through the heater, etc. 131 COCHRANE HEATING ENCYCLOPEDIA II ii Cocliraiic ('iiinhiiicd Oil Sviiiinilnr iiml M iillli 'I'liiil: fur nrrlrlng mid purifying tin: exiiiiiisl frniii wise by the motion of the steam, as the ribs prevent. This is the correct methoil of making use of inci'tia in the separation of liciuid particles from a current of steam or gas. Water weiglis about 1600 times as much as steam, volume for volume, at atmospheric pressure, and if the direction of the steam current be changetl the water will shoot on ahea' been possible after Cochrane Steam Sepa- rators have been installed to reduce the cvlinder oil supph' 50 per cent, or ''''ichniiie"Uti»-Piere''' 1 ., 1, • • ',.1 ^. ''ilea IN , Separator for more, while ot)tammg at the same time i -iriicat Pines' 134 STEAM AND OIL SEPARATORS better lubrication and less friction and near. Where the boilers are subject to priming, where the steam piping is long or exposed, or where superheaters arc used, not only should separators be installed at the far end of the steam line to protect the pump, engine or turliine, Ijut a se])arator should also be in- stalled near to and draining liack to the boiler. This will return the water carried up by foaming and priming, and if superheaters are used, will enable them to superheat instead of merely drying the steam. It is highly important that no water in the liquid state be carried over from the boil(>r to a su]ier- heater, since the scale-forming matter dissolved in it, even if only small in amount, will in time so coat the inner surfaces of the superheater as to diminish its efficiency and even cause its destruction. Coch ra nc Receiver SeiinraUir. i% ;? 4 / f ' RECEIVER SEPARATORS For l(jng systems of steam piping, and where heavy slugs of water from pockets or exposed piping are to be feared, in fact, as a matter of insurance, wherever engines or turbines are put in, Cochrane Receiver Separators shoukl Ije installed. The capacious receiver serves to hold masses of water until they can be drained away by the trap, and also acts as a reservoir of steam, close to the cylinder, thereby increasing the average initial pressure, and at the same time liaving a cushioning effect on the long column of steam in tlie piping and reducing vibration. Cochrane Steam and Oil Separators are made in all sizes and for all pressures, and for vertical, horizontal or angle pipes. State your requirements and send us a sketch of the propcsed arrangement and we shall be pleased to devise layouts and to send special literature. (■ f 135 COCHRANE HEATING ENCYCLOPEDIA INTERIOR VIEW COCHRANE MULTIPORT SAFETY EXHAUST OUTLET VALVE A CasiiKj, having two removable doors or liniul-holo:, providuig easy access III (/(.s/.x for regrinding, and to sjirings fur rciiiovid, etc. B \'idve Plalc. curries ilnsh puis which giiiilr anil cnxliion Ihc ridres, and ichicli are horeil sintidliiniiHisIy loith seeds, insuring idiginnent . (' Pressure J'lale, ntalinn liinileil to prevent exceeding a prc'ilelermined pressure. D Bronze Vcdve l)is];s. A number of small disi.:s instead eif one large disk. Less leeiylit and Irani. Iiss liiininn ring. Clinneis of all becoming inop- erative at iinee are exeeedinglij remote. E \ ieicel-l'lali d Strii Springs. Can he changed if a different back pressure is desired. F Brass Vatre Stems. Serve to lift disks off seals when exhausting free to almosphere. (J Brass Guide Posts for pressure plate. H DasJi Pots, water filled, more effective than steam or air filled. I Steel shaft. Oidij werrking part passing Ihroiigli packing. Not directly attaelu d III disks, henci no piissitnliti/ of interfering icith opening of disks througli nrer-tiglitening of gland, etc. ./ Bronze Spindle for raising and lowering pressure plate. K Bronze Gears, not required in horizontal form. L Adjusting Hand-Wheel. ]'alves are also arranged for control from distance, by chains, rod, Iiydranlic pressnrr, electric motor, etc. 136 MULTIPORT BACK PRESSURE VALVE THE COCHRANE MULTIPORT SAFETY EXHAUST OUTLET VALVE FOR CONTROLLING THE PRESSURE IN EXHAUST STEAM HEAT- ING AND DRYING SYSTEMS The exhaust steam heating system must be protected by some reliable form of escape or safety valve, otherwise if the amount of steam delivered Ijy the engines, pumps, etc., should be greater than could be condensed in the heating system, pressure would accumulate and even boiler pressure might be attained. Our attention was first drawn to the vital import- ance of this matter by investigations which we made some years ago into the causes of burst or broken feed-water heaters. In almost every case we found that explosions, blowing out of plates, etc., had been due to the sticking of the l)ack pressure valve. The faulty valves were of various types. In some the disk was held to its seat by a weight acting through levers, iir others by a spring, while in others the valve did not seat at all, but was of the cjdindrical type, sliding past and opening ports for the escape of the steam. The failures were traced to various defects in design and construction of the valves, in- cluding such faults as sticking or rusting of the valve disk to the seat, overtightening of glands wheremoving parts connected with the disk passed through the housing or casing, over- weighting and tying down by the operator, interference of ex- ternal objects with the moving parts of the valve, and in the case of cjdindrical or sliding-valves, binding of the valve against the valve seat. So-called balanced and double-seat valves appeared to be particularly liable to jamming or sticking, the balanced valves of the disk type because of the small force available for opening the valve and the sliding or cylindrical valves for the reason that if made loose in their seats, so that they would not stick, too much steam would escape, while if they were made with a nice fit, sticking or jamming would sooner or later occur. While considering safety first, many other possibilities of im- provement were noted. For instance, it was found that most valves could be adjusted for different back pressures onlj^ with difficultj'. In some cases it was necessary to lift and shift weights weighing several hundred pounds. In others, the 137 COCHRANE HEATING ENCYCLOPEDIA 138 MULTIPORT BACK PRESSURE VALVE Showing how easy it is to change the back f.resswre with a Cochrane Multiporl. tension of springs could l)e adjusted only with considerable difficulty by means of a wrench, after having clinilicd up to the valve, and in many if not most cases, there Avas no proper limit to the load which could be put upon the valve (.lisk, thus making it possil.)le for an ignorant or careless att(>ndant to set the valve at a jiressure which would ru])ture the connected piping, heaters, radiators, etc. It appeared to us desiral)le to have a valve A\'hich could be easily and conveniently ad- justed, even from a distance, l)ut which coultl not be overloaded by any means. A great advantage in being able to adjust a valve cpiickly and easily is that the Ijack pressure may thus be suited to the varying heat reciuirements throughout the day, that is, a high back pressure can be carried in the morning when much heat is reciuired, but the pressure can lie eased off or the engine allowed to exliaust freely to atmosphere in the afternoon when the building is warmed up, thus greatlj- improving the steam economy of the engine at such times. It also appeared desiraljle to reduce the tendency to noise and clatter, especi- ally as back pressure valves are almost always installed in the neighborhood of factories, hotels, institutions and other places where noise is objectionable. Closely allied to noise and clatter is the destructive hammering action of the valve upon its seat. In many valves the moving parts are large and heav}', and combined with the counterbalancing weight, deliver a powerful hammer blow uponthe seat and other parts of the casing, especially when the engine is exhausting at such a rate that the steam escapes in intermittent pufl's at each stroke of the engine. A good rig where the valve is outdoors or at a distnnce. 139 COCHRANE HEATING ENCYCLOPEDIA Thirlii-iiicl/ C'nrliriiiii: MiiUiporl liuill for Jiiirk-l'rrK.siirr Service, ciuilrrillcil frnni bniirr nxini Jinnr !>[/ nnls iiml iji ars. The requirement as to safety is met by using a number of small disks instead of one large disk, so tliat in event of one disk becoming stuck or jammed, the others will still release the steam and prevent excessive pressures from building up. AVith four or five disks instead of one, tlu> chances of com])lete stop- page of the valve become practically infinitesimak The smaller disks are naturally- much lighter and also rerjuire much less lift, and move with a lower velocity than do largiMlisks, but to obviate all ])()ssibility of hammer- ing (if the disks upon their scats, adequate dash-])ots, placed in the steam sj^ace instead of air space, so that they will at all times lie tilled with water of condensation, //) sniiir (Yi.srs ilir cshniixi liiir miisi rmi lu'v employed. Water has ,„ilhn„r,l. hnn:o„lnllij iiwkr Ihr rnlmg. ui ),|->(.n found to be much Exhaust OutlctValve with vertiadinhl'and "^'^'''-' enec'tive m dash- horizontal outlet exactly fills the bill. pots than air or steam. 140 MULTIPORT BACK PRESSURE VALVE / 7 i ' A simple rig for optraliiig ralrcn placed beneath floors. To hold the disks to their seats, iinlividual springs are fitted, since springs have httk' inertia, and thus do not add to the hammering effect. For adjusting the tensi(m U])()n all the springs simultaneously, a pressure plate (see page 138) is employed, the pressure phite being movable, so that the tension can be adjusted at will, l.)ut within limits, so that a predetermined maxi- mum back pressure cannot be exceeded. Several different means can be provided for adjusting the position of the pressure plate, as for instance a hand wheel on the outside of the casing, shown on page 13t); a rod-and-gear arrange- ment, shown at top of page 140; a chain, at bottom of page 140; hydraulic pressure cylin- der, as on this page; and by means of electric motor from the switchboard. It is thus possible to ad- just the valve from a distance, as from the engine-room floor, without climbing upon ladders or out upon the roof, as is necessary with prac- tically all other types of valves. The valve casings are so design- ed that they may be inserted in vertical steam pipes, horizon- tal steam pipes, or at angles, making them particularly adaptable, and often ]]'///' some I iislallol/oNs, ronlrni hij means of hydraulic pressure may hr most smtahle, since it permits of the instant closing or opening of the valve from any point, such as the engine-room floor, as when throwing units over from non-condensing to conden- sing operation . 141 COCHRANE HEATING ENCYCLOPEDIA saving the cost of elbows and other fittings. In all eases snita))le hand hole plates and covers are provided, so that the individual disks can be removed or ground to their seats while in place in the valve. All parts of the valve in mo\'ing contact are made of Ijronze, l)rass (jr other non-corrodible material, the dash-pots for instance being line(l witli brass, while the plungers are of l)r(.)nze. These valves are built in all sizes, as the use of the Alultiport ))rinci])le removes all limits a])plying to single lai'ge disks, ^'alves of 20, 24, 30 and 3(3 inches in diameter are in use b}- such concerns as Henry Disston & Sons, Ten- nessee Coal, Iron tt U. R. Co., Bethlehem Stei'l Co., Pennsyl- vania R. R., Kansas City (las Co., Baltimore it (.)hio R. R., and many others equally well-known. The \'alve meets with immediate acceptance l)y owners and consulting engineers who ai)preciate the importance of absolute safety- and the ad- vantage of being al)le to atljust the back jtressure easily and frecjuentlj'. THE COCHRANE MULTIPORT FLOW VALVE FOR EXHAUST STEAM TURRINF?? In a preceding cha])- ter we referred t(.) the possibility of installing exhaust or low-pressure turbines to consume surplus exhaust steam ir/io'c // is ilc.sirrd Id niiil.i mi lUiijlf liirii , Ihis Ijiiir (if viiJi'i' iinl mill/ /irrfnniiK llic jiiirl. iif II snlrlij ij-liiiiiM oiillrl nilir. hill iilsn lal.-cs llir /)/(/<■(■ ()/();( I'lliiiir hi llir pi pr line. Tilt' Ciiclimiii Miilliporl Snfclij Exliiiiixl Oiillel Valve is siiileil In Iwrizoiiliil or angle pi/ies, lis well as lei veiUnil pipes. 142 MULTIPORT BACK PRESSURE VALVE « V The Coelinnie Midtiport Flow Valve is so orronged thai it closes off aulomalically as soon as Ihe pressure in the exhaust line approaches a predetermined minimum, say atmospheric pressure, that is, it teill dam hack the flow of steam so that this pressure will be nniintainvd in the exhaust line even though the pressure in the intermediate stage of the turbine falls to only a few pounds absolute, as will happen at partial loads. not required in the heating system. In such plants, the turbine governor is arranged to operate two governor valves, one controlling the admission of the exhaust steam, and the other the admission of live steam whenever the supply of exhaust steam may be deficient or entirely lacking. This valve gear is so adjusted that the low pressure valve opens before and closes after the high pressure valve, so that exhaust steam is used bj' preference at all times. However, when there is little or no exhaust steam, and the turbine is running light, it may happen that the vacuum from the con- densers will back up into the intermediate stage into which the exhaust steam is received, and if nothing were to prevent, would extend back into the engine exhaust line and draw in air through leaks in the piping and through piston rod and £ I 143 COCHRANE HEATING ENCYCLOPEDIA Codirniic Horizonliil Flow \';s. This air, entering the condenser, greatly increases the work of the air pump and results in a lower vacuum, which is highly detrimental to the efficiency of the turl)ine, each inch in vacuum above 26 ins. affecting the steam consum]3tion of a high pres- sure turbine by 6 to 10%, and of a low pressure tur- liine nearly twice as much. To obviate this trouble, we have developed the Cochrane Multiport Flow \'alve, shown on page 143 and on this page. This valve establishes a level of ]>ressure in the exhaust line l)elow which the engine exhaust pressure is not al- lowed to fall, regardless of the pressure or vacuum existing on the turbine side of the valve. In other words it acts as a dam, holding back the steam whenever the pressure on the turbine side of the valve falls below a predetermined point, usually fixed at slightly above atmospheric pressure. THE COCHRANE MULTIPORT CHECK VALVE FOR BLEEDER TURBINES In some turljine plants there is not a surplus of engine exhaust which can be used in a low pressure turbine, but on the other hand, steam is bled from an intermetliate stage of a con- densing fur])ine, to supplement the exhaust of pumps, engines and other apparatus for heating and industrial uses. In such cases it is highly import;int that steam l)e prevented from flowing l)ack from the intermediate pressure piping into the turl)ine, as with no load on the latter such steam flowing from the intermediate stage to the condenser might overspeed the turbine, and thus bring about a serious accident. This can of course be ])reventcd l)v placing a valve controlled Ijy an emer- gency governor in the bleeder connection, but that would result in the stoppage of the turl)ine and interruption to work. A much better arrangement is to install a Cochrane Alultiport Valve between the turbine and the low jiressure piping, the valve opening toward the latter so th;it steam will be dis- charged freely into the heating or other steam-using system, but cannot flow back from the latter into the turbine. 144 HEATING TABLES AND DATA TABLES AND INFORMATION RELATING TO EXHAUST STEAM HEATING TEMPERATURES AT WHICH VARIOUS ROOMS ARE ORDINARILY KEPT Stores, offices, schools, etc 68° Living rooms in houses 70° Lecture halls and auditoriums 62° Sleeping rooms 55° Bath rooms 72° Sick rooms 72° Factories, \Yorkshops, gymnasiums, etc 50°-68° Halls, passages, corridors, vestibules .54°-60° Churches 54° Prisons 65° day, 50° night Hot houses 77° Cooling houses .59° Swimming halls 85° Non-heated cellars, assumed 32° Non-heated vestibules, corridors, etc., in contact with external air 23° Airspaces between roof and ceihng of rooms: Metal and slate roofs 14° Brick or concrete roofs 23° HEAT LOSS FROM BUILDINGS Heat is lost from buildings by (1) conduction and radiation through walls, windows, doors, floors, etc., (2) leakage of warm air through cracks around doors and windows, (3) and removal of air by the ventilating system. The loss of heat through walls, floors, etc., depends upon the building materials used, the thickness and number of layers, and the temperature difference of the air on the two sides. The exact amount of heat thus lost is difficult to predetermine and all figures are based largely on exjier- ience. The chart on page 146 is made mainly from a table printed in a Handhnok for Healing and Ventilating Erigineerx, by James D. Hoffman, M. E., and Benjamin F. Raber, B. S., M. E., and stated by them to be the average practice of a number of American and foreign engineers. These figures are for a southern exposure. For northern exposure multiply by 1.30; eastern, 1.1; western, 1.2; all around exposure for an entire building, 1.16. For a building heated during the day only, in un- exposed positions, multiply by 1.1; in exposed positions, 1.3; if heated only occasionally, 1.5; if .subject to high winds, 1.2. Recent investigators have found that corrugated iron transmits about 1.5 B. t. u. per square foot superficial area per degree difference of tem- perature per hour. {Healing and Vent. Mag., IX, 10, 19.) 145 COCHRANE HEATING ENCYCLOPEDIA ^ed vy i>c ^sd nj. e o9 oi. OC 03 \ \ 1 \ \ 'J I !5 \ .Get: >. V \N \ \ \ V \ \ \\ \ \\ a \ V s V \ \ \ w .\ V \\ '■i ? (t) k V ^ \\ \ \ v\ V \ w u\ Q \ s \ \ \ \ \ \ v^ w a\ \ V \ \\ \\ \ \ \\ w \\\ \ \ k \ s v \ \ \ \ v^ \ A\i\\i\ .1^ \. s\ \ \ \, \ \ ^ \\U\\M \ s s. \^ w \ \ , \ \ o V \ V s \' \ V W \\\ \\\ \ w \ \ s w \ \ \ v \ \ \ \ \ \ \ s V \ \; \\ \ f^ \ \ \ \ w \ \ A \\ \\ \ \ \ \ \ V \\ \ \\^ l\ m pi s \ \ \ \^ V A 1 Iv 1 '"5 >1 \ \, \\ \^ \^ w ™ \ \ s s^ L^ ^> A' w \ \ \ \ \\1\\\\\\ m \ \^ ^ \\ \\\\\v \ s \>A\ \^ m ll (1 . "^ ? v'« ^«^»^ »K«(na i!;5t5 « \ \ x A \n 1 ♦ \ \ \ \w \\\\\1 r, \ \ \ \ Vv •) \ \ \ w \ s "^ ^ ^ o: o ' o 5 o OS o o r jnoLf ^3c/ ^oo^ sJO/^6s ^y/ •^ ?& 146 HEATING TABLES AND DATA HEAT LOSS THROUGH DOORS British thermal units per square foot of door per hour for 100 degrees difference in temperature on opposite sides of door, other temperature ditTerences being proportional: Thickness Soft Wood Hard Wood Inches Inner (Jater Inner Outer 1 82 89 108 125 1 70 76 98 113 Ij 56 60 S5 95 2 47 50 75 S3 2| 38 41 66 73 MEAN MAXIMUM AND MINIMUM TEMPERATURES AND LOWEST TEMPERATURE FOR YEARS 1908-1912 IN 21 CITIES The amotutt of radiating surface is usually based upon that I'equired to heat the building to 70° with an outside temjjerature 10° above the lowest recorded for the locality in which the system is installed. Zero is usually assumed in the latitude of Pennsylvania. In more southern latitudes the outside temperature is taken higher and in northern latitudes lower. The following table shows the mean maximum and minimum temperatures for 21 cities for the months of December, January and February for four years: (See also pages 182 and 183). Lowesi Temperature December .January Feb llar^■ Location On Max Min. Max Min Max Aim. 08-09 —23 0<)-10 —21 10-U —21 ii-n Rec- ord Quebec 21 10 15 1 17 3 —23 39 26 27 36 38 21 ,38 24 ' 39 25 3 5 ~l 4 9 — 3 —13 Xew York 39 — 6 BuiTalo*** 34 23 31 18 31 17 ~ 1 — 6 3 —13 —14 Philadelphia 41 29 39 26,42 28 9 5 17 — 6 Norfolk** 52 64 36 47 48 65 33 ' 51 46 66 34 47 23 13 19 ■'26 11 26 9 Jacksonville 10 Atlanta 51 35 51 35 , 54 36 S 10 12 6 — 8 New Orleans 46 35 64 48 65 48 28 26 22 23 7 Houston 63 45 66 46 66 45 21 21 16 15 Nashville 48 32 49 30 51 32 o 6 1 — 6 —13 Louisville 43 31 42 29 1 45 27 3 1 6 — 8 —20 St. Louis 41 26 38 22 ' 42 25 — 1 — 1 2 —14 —22 Kansas Citv 39 24 35 19 41 23 — 6 — —10 —20 —22 Cohmibus 38 24 35 21 38 22 — 4 4 — / —20 33 22 23 29 31 18 31 17 34 18 21 (J —10 — 1 2 —12 —16 —•H Chicago 34 —23 Minneapolis 26 12 18 1 ' 25 8 — 27 —18 —24 —31 —33 Denver 41 17 48 22,44 19 — 4 —13 —IV -8 -29 Seattle* 44 36 42 34 45 35 12 22 19 3 San Francisco**** . 56 46 54 46 57 47 35 36 38 39 29 * Includes January and February 1908 instead of 1912. ** Includes winter of 07-08 instead of 'lO-'ll. *** Does not include Dec. '08. **** Does not include Dec. '09. 147 COCHRANE HEATING ENCYCLOPEDIA LOSS OF HEAT BY LEAKAGE The exact amount of heat lost through cracks around doors and windows and through waUs varies with the care used in their construction, and cannot be determined accurately. The following chart seems to accord with good practice, and may be used in ordinary cases. It is based on the assumption that leakage causes from one to two complete changes of the air in a room per hour. ? S > O 1 u / r / / / - — / / f A / . i f [a f i W '/ / t m § f I f 1 / — / ■ , f 1/ / i \7 — -. / / 0^ i^ / 7 / / / 1 / / / i / / / / 7 / / / / / / 1 ' > / / / / / // / // / r OQO ^OOO 3000 4OO0 „„^„ ,„^^ /Veof Losf- 'n B.t w Heat lost hy Air Lenkdije fur racli 10° F. Difference in Tmipcridure belteeen inside ami ouisnle. R. r. Bolton gives the following rule for estimating leakage losses through windows: I^eakage in B. t. u's. jicr hour equals p(!rimcter of window openings in feet multi])lied liy ~'2 for ordinary construction; or multiplied by 31 for metallic stripped sashes. 148 HEATING TABLES AND DATA TEMPERATURE EQUIVALENTS OF WIND VELOCITIES In figuring heating requirements it is necessary to take into account the velocity of the wind as well as the temperature that is likely to be encountered. Mr. E. F. Tweedy compares New York and Chicago and finds that, figuring on a basis of mean monthly temperatures, the heating requirements of Chicago should be only 19 per cent, greater than New York. However it has been found that the actual coal requirements are practically 100 per cent, greater. He goes on to say: ''This apparent discrepancy can undoubtedly be explained by taking two additional factors into consideration — one of which has a verj' material bearing uijon the heat loss of a building with a given exposure, while the other has an important bearing upon the amount of coal required to offset a given loss of heat. The first of these factors is that of wind velocity; the second is that of evaporation, or the average number of pounds of water evaporated into steam per pound of coal. "The average velocity of the wind during the heating season in Chicago is a little over 18 miles per hour, while the average wind velocity in New York City during the months when heating is required is approximalcly \-i miles per hour. As the wind pressure varies approximately as the square of the wind velocity, the mean wind pressure during the heating season in Chicago is approximately twice that existing in New York City. Now the loss of heat by air leakage is naturally a function of the mean external air pressure that results from the velocity of the wind. Therefore, in order to show the effect which the higher average velocity of the wind in Chicago has upon the heating requirements of the buildings in that city, as com- pared with those of similar buildings in New York City where the average wind velocity is considerably lower, it is only necessary to estimate approxi- mately the average relation of the heat loss due to leakage to the total heat loss under NewYork City conditions. In the latter city it has been found that the square feet of window surface of office and loft buildings averages about '20 per cent, of the total exposed wall and glass surface; hence, by referring to the expression for the total heat lo.ss, — +20, where W and G equal the total exposed wall ami window surface in square feet respectively, it will be seen that the average heat loss from leakage, under New York City con- ditions, is approximately 35 per cent, of the total heat loss. Based upon the increased air leakage alone, the Chicago heating requirements are therefore 135 per cent, of those existing in New York City. "From tests made upon a vast mmiber of IlUnois coals by the United States Geological Survey, it would appear that a figure of 11,000 B. t. u. per pound may be taken as representing the average heat content of these coals as fired. Pea coal, such as is used in the majority of New York City buildings, will probably average something over 12,000 B.t.u. per pound. Consequently, if these different kinds of coal were burned with equal efficiency, the amount of Illinois coal required would be about 110 per cent, of "the amount of pea coal necessary to supply an equal quantity of heat. It is very probable, however, that the actual ratio is more nearly 149 COCHRANE HEATING ENCYCLOPEDIA ooe ooooBi ooaom ooooirf 000031 Lfsm^^ ^ oo/ a/ty/i j3 150 HEATING TABLES AND DATA expressed by 125 per cent., due to the fact that pea coal, when used in the average heating plant, will unquestionably show a considerably higher efficiency than that shown by such grades of soft coal as are commonly used in the heating plants of Chicago. Hence, if this contention and the fore- going assumptions are correct, we have an explanation of the fact that the amount of coal required in Chicago for heating a given building is twice what it would be were the building located in New York City; for 1.19 X 1.35 1.25 = 2." ALLOWANCE TO BE MADE FOR WIND By W. H. Whilten. "A comparison of records taken at the group of build.ings of the Har- vard Aledical School on the total heat expended and average temperatures and average wind velocities showed that 1 mile of wind movement per hour required substantially the same amount of heat supply as 1 deg. change in temperature. A further study of similar records, however, has shown that there is a greater proportion of loss due to wind movement as the tempera- ture drops. "As a rule for personal guidance, the author has adopted the following: From 40 to 15 deg. plus, 1 mile of wind movement per hour is equal to 1 deg. drop in temperature; from 15 deg. plus to 20 deg. minus, 1 mile of wind movement per hour is equal to 1.15 deg. drop in temperature. This is for buildings constructed in the ordinary manner, that is, without protected windows. Applied strictly to the glass surface, with leakage standardized, the loss from wind movement may be calculated as onlj- three-sevenths of the loss under usual and ordinary conditions. This not only applies to the sides having the so-called greatest exposure, but, owing to the suction or non-pressure existing on the sheltered sides, should be apphedto all sides of the building." LOSS OF HEAT WITH FORCED VENTILATION Ordinarily in office buildings and in dwelling houses, leakage through doors, windows, etc., is the only means of ventilation. In workshops, theatres, assembly halls, schools, etc., however, there is usually provided some means of supplying fresh air through ventilating pipes, and what is known as the indirect method of radiation, in which the cold incoming air is passed over surfaces which temper it before it passes to the rooms, is employed. In the plenum system the circulating fan forces the air through the building while in the exhaust or vacuum system, an exhausting fan is put in the attic to remove foul air by suction. A combination is often used. The chart on page 150 shows the heat units that will be required for heating given volumes of air through various temperatures. To esti- mate the volume of air required, the table on page 152 will be found convenient. 151 COCHRANE HEATING ENCYCLOPEDIA CUBIC FEET OF AIR TO BE SUPPLIED PER HOUR PER OCCUPANT AUTHORITY Allen Prausnitz Eietschel I Many Morin ' Stats ' Laws 1400 2100 Assembly rooms, short meetings. . Assembly rooms, long meetings . . Churches, theatres and halls 2000 1000-2000 , Theatres 1. . . . 900-1100 UOO-1700 . Office rooms llSOO Toilet and bath 12400, Dining rooms 1800 Living rooms 1800 700-1200 Hosi)itals 3600 2600 for ordinary sickness 2100-2500 2000-2400 . ' ' for wounded and lying-in 3500 5300 1100 1400-18(J0 . 3000 . " for epidemic diseases " for children BaiTacks during day Barracks dui-ing night Barracks and woi'ksho]5s Workshops, ordinary \\'orksliops, unhealthy trades Schools, children. ...' 2400 425-525 Schools, adults 900-1100 Prisons i Prisons for sleeping Prison.s — snlitarv cells ' 1200 5000 2100 475 700 2000 3500 400-500 800 800-1000, 1800 1700 350 650 The following rule may also be used to determine the necessary amovmt of air that should be suiiplied to a room: nS A = 10,000 — 1 a — 4 where A =the cu. ft. of air to be su]iplieil, n = number of sources (.)f C"( ).; , S =cu. ft. COo from each source jier hour, a =allowable limit of CO, in cu. ft. m 1(I,0(.)0 cu. ft, of an-. (a should not exceed 7, and a^lO is the sanitary limit.) An average man gives olT 0.5 cu. ft. CO^ jier hour at rest and from 0.5 to 1.5 cu, ft. when at work. In rooms of ordinary size and having only one air duct, the hourlv air change should not exceed five times the cubical contents of the room on account of danger of excessive draughts, {iriilli). The Illinois law provides that a definite amount of air, 1500 to 1800 cu. ft. per occujiant, according to specified conditions, shall be supplied, unless the cubic space in the workroom be over 2000 cu. ft. per occupant and the outside window and door si)ace be equal to one-eighth of the floor space. Every foot of iUuminating gas burned requires 1300 cu. ft. of fresh air. The following table shows the cubic feet of freshair that can be supplied with a definite heat loss. Por example, suppose air is furnished to a room at 68° and removed at 72° (temperature difference 4°) and that 2000 B. t. u's. are lost per hour. From the table we find that the air 152 HEATING TABLES AND DATA % J change for 1000 B. t. u's. is 14,110 cubic feet, and multiplying this by 2 we have 28,220 cubic feet of fresh air suppUed under these conditions. HOURLY AIR CHANGE IN CUBIC FEET WITH 1000 B. T. U'S. LOST. BASED ON DRY AIR. Temperature Differences of Incoming and Outgoing Air, °F. Temperatures of Outgoing Air 64° 72« 80= Cu. Ft, Fresli Air per Hour 2 27790 28220 28620 4 13895 14110 14310 6 9263 9407 9540 S 6947 7055 7155 10 5558 5644 5724 12 4632 4703 4770 14 3970 4031 4088 16 3474 3527 3577 18 3088 3136 3180 20 2779 2822 2862 HUMIDITY H iijte, the German hand-book, states that for normal rooms (art galleries, assembly halls and textile factories excepted) with clean air the humidity should be 2,5-30%. (These figures seem rather low as the humidity of the most arid regions is usually as much as this.) Too moist air is worse than too dry air, and 70% of humidity should never be exceeded. Prof. Car- penter states that air should be from 50 to 70 per cent, saturated in order to feel pleasant and be of the most value for ventilating ])urpo.ses. Snow gives some data on the cost of increasing humidity as follows: "The amount of heat and fuel necessary to moisten air is not generally appreciated. To illustrate this point, take the amount of heat required to moisten air entering a furnace at 30 degrees with a relative humidity of 65, so that a relative humidity of 50 will be maintained in the rooms kejit at 70 degrees. (By relative humiditj- is meant the ratio in hundredths between the quantity of moisture present in a given volume and the quantity it would contain if saturated.) Assume that 50,000 cubic feet of air per hour pass through the furnace: One cubic foot of saturated air at 30° F. con- tains approximately 2 grains of moisture, and with a relative humidity of 65 would contain 1.3 grains. Each cubic foot of air at 30° expands to 1.08 cu. ft. when heated to 70°. One cubic foot of saturated air at 70° contains about 8 grains of moisture. With 50 relative humidity 1 cu. ft. of 70° air would contain 4 grains. "The amount of moisture tliat must be supplied by the eva]:)orating pan in the furnace is the difference between 50,000 cu. ft. per hour / 1.08 - 4 and 50,000 / 1.3. The difference equals 151,000 grains or 21.6 povmds per hour. "Since about 1000 heat units are required to evaporate 1 pound of water, 216,000 units per hour are absorbed, equal to the heat utilized from the burning of 21 jjounds of coal." i' 153 COCHRANE HEATING ENCYCLOPEDIA PROPERTIES OF AIR OR WEIGHTS OF AIR, VAPOR OF WATER, AND SATURATED MIXTURES OF AIR AND VAPOR OF DIFFERENT TEMPER- ATURES, UNDER THE ORDINARY ATMOSPHERIC PRESSURE OF 29.921 INCHES OF MERCURY Bij R. V. Carpenter y Air at dif- ■atures, the being 1.000 .a §"§ -Q 0^ 3 3!C o Mixtures of Air sat urated with Vapor Elastic- Force of Weight of a cubic foot of riiixture t-. c.f3 c ^ c: o ^ ^<'- tfie Air in tfie mix- — "5 P. H 1^1 .So = W.S c ture of Air and^'apor in incties of Mercury Weidht of the Air pounds Weight of the A'apor in pounds Total weight of mixture in pounds 1 2 3 4 5 6 7 8 0° . 035 . 0864 (144 29.877 .0863 . 000079 . 086379 12 , 060 .0842 .074 29 . 849 .0840 .000130 .084130 22 . OSO .0824 .118 29 . 803 .0821 . 000202 . 082302 32 1 . 000 .0807 .181 29 . 740 .0802 . 000304 . 080504 42 1 . 020 .0701 .267 29 . 654 .0784 .000440 . 078840 52 1.041 .0776 .388 29 . 533 . 0766 .000627 .077227 60 1 . 057 .0764 .522 29 . 399 .0751 .000830 .075930 62 1.061 .0761 . 556 29 . 365 .0747 .000881 .075581 70 1 . 078 .0750 .754 29.182 .0731 .001153 .074253 72 1 0S2 .0747 . 785 29.136 .0727 .001221 .073921 S2 1,102 .0733 1 . 092 28 829 . 0706 .001667 . 072267 02 1 . 122 .0720 1.501 28 , 420 . 0684 .002250 .070717 100 1 . 130 .0710 1 . 029 27 . 992 .0664 .002848 .069261 102 1 . 143 .0707 2 (136 27 885 . 0659 . 002997 .068897 112 1 . 163 .0604 2 731 27.190 .0631 . 003946 .067042 122 1.1S4 . 0682 3.621 26 . 300 . 0599 .005142 .065046 132 1 . 204 .0671 4 . 752 25.169 .0564 .006639 .063039 142 1.224 .0660 6.165 23.756 .0524 .008473 . 060873 152 1 , 245 . 0649 7 . 930 21.991 .0477 .010716 .058416 162 1 , 265 .0638 10.099 19 . 822 .0423 .013415 .055715 172 1 . 2S5 .0628 12.758 17.163 .0360 .016682 .052682 1S2 1 . 306 .0618 15.960 13.961 . 0288 .020536 .049336 192 1 . 326 . 0600 1 9 . 828 10 . 093 . 0205 .025142 . 045642 202 1.347 . 0600 24 . 450 5.471 .0109 . 030545 .041445 212 1.367 .0591 29.921 0.000 .0000 . 036820 .036820 154 HEATING TABLES AND DATA PROPERTIES OF AIR-CONTINUED Mixture rated wi f Air Satu- th \'apor ^^1 by one Air per •^1 t '^ L. I- Z C ■2 3 •^s II 3 is i b^ O tr g« C X. fe ■:o ^ a g Q > o S ° > o a g n o a; ■ a ti P a. II « ° 1 s 1 13 bo Xt o 5^ J3 C - :: rf ^ Op:*: 1 9 10 11 12 13 14 15 0" . 00092 1092.4 .02056 . 02054 48 , 5 48 7 12 .00115 646 . 1 . 02004 . 02006 50 . 1 50.0 22 .00245 406.4 .01961 .01963 51,1 51.0 32 .00379 263 . 81 3289 .01921 .01924 52.0 51.8 42 .00561 178,18 2252 .01882 .01884 53.2 52.8 52 .00819 122.17 1595 .01847 .01848 54.0 53.8 60 .01083 92 . 27 1227 .01818 .01822 55.0 54.9 62 .01179 84.79 1135 .01811 ,01812 55.2 55.2 70 .01548 64 . 59 882 .01777 ,01794 56 . 3 55 . 5 72 .01680 59 . 54 819 ,01770 .01790 56 . 5 55.8 82 .02361 42 . 35 600 .01744 .01770 57,2 56 . 5 92 . 03289 30.40 444 .01710 .01751 58.5 57.1 100 . 04495 23 . 66 356 .01690 .01735 59.1 57.8 102 . 04547 21.98 334 .01682 .01731 59.5 57.8 112 . 06253 15.99 253 .01651 .01711 60.6 58.5 122 . 08584 U . 65 194 .01623 .01691 61.7 59.1 132 .11771 8.49 151 ,01596 .01670 62.5 59.9 142 . 16170 6 . 18 118 ,01571 .01652 63.7 60.6 152 . 22465 4.45 93.3 ,01544 .01654 64.8 60.5 162 .31713 3.15 74.5 .01518 .01656 65.9 60.4 172 .46338 2.16 59.2 .01494 .01658 67.1 60.3 182 .71300 1.402 48.6 .01471 ,01687 68.0 59.3 192 1 . 22643 .815 39.8 .01449 68.9 202 2 . 80230 .357 32.7 .01426 70.2 212 Infinite .000 27.1 .01406 71.4 155 COCHRANE HEATING ENCYCLOPEDIA QUANTITY OF AIR, IN CUBIC FEET, DISCHARGED PER MINUTE THROUGH A FLUE OF ONE FOOT CROSS-SECTIONAL AREA EXTERNAL TEMPERATURE OF THE AIR, 32 ALLOWANCE FOR FRICTION 50% F.; By R. ('. f'(ir]>eidcr. Height of Kxcess of temperature of air in flue above tliat of external air fiue in feet 5° 10° 15° 1. 5. 10. 15. 20. 25. 30. 35. 24 55 77 94 34 76 108 133 lOS 153 121 171 133 I ISS 143 I 203 42 94 133 162 18S 210 230 248 40. 45. 50. 60. 70. 80. 90. 100. 125. 150. 153 217 265 162 230 282 171 242 297 188 264 325 203 2S6 351 217 306 375 220 324 398 243 342 420 273 383 468 298 420 515 20° 25° 48 54 109 121 153 171 188 210 217 242 242 271 265 297 286 320 306 342 325 363 342 383 373 420 405 465 453 485 460 516 i 485 534 542 604 596 665 30° 59 134 188 230 265 297 325 351 375 398 419 461 497 530 564 594 662 730 50° 100° I 150° 76 108 167 242 242 342 297 419 342 383 419 453 484 514 541 594 643 688 727 768 855 942 484 541 593 640 684 724 765 835 900 965 1027 1080 1210 1330 133 298 419 514 593 663 726 784 838 889 937 1006 1115 1185 1225 1325 1480 1630 ROOMS HEATED OCCASIONALLY According to Rietschel, for rooms of a considerable size, heated occasionally and only for short intervals of time (churches, halls, etc.) the necessary amount of heat cannot be determined from transmission factors but should be based on the following computations. (a) For well arranged heating surfaces: F- K(t— t,J I ¥^ y 25 ( t — t , 2 ^ 10.764 y-^^ 9 Z (li) For badly arranged heating surfaces (as in hot. air heating): W= ^■] w= - F - K (t— 1„) 0.764 L 40 + 50(t— t, )"] 10.764 L'" ' 9Z J Where W =the hourly amount of heat required in B. t. u's. F =the window surface in sijuare feet . F,^the combined surface of walls, ceilings, floors, pillars, etc., in square feet. K =the transmission coefhcient (for single windows =1.1). t =the required interior temperature, ti =the temperature of the air before heating (about 32°). tn =the lowest outside temperature. Z =duration of heating in hours. This fornmla applies to rooms not over forty feet high. For each additional three feet over forty add 5% to the calculated value of W. 156 HEATING TABLES AND DATA AMOUNT OF HEATTO BE SUPPLIED Having calculated the heat loss from a building or room, the heat given off by the bodies of the occupants and the lights is subtracted and the difference is the heat to be added or abstracted by the heating and ventilating system. The following table shows the amount of heat given off in B. t. u's. per hour (in the case of gas and electricity per candle power hour) according to various writers: Source Authority B. t. u'.s. Adult at rest Rubncr 380 Adult at work Rubner 470 Adult at hard work Rubner 550 Child, six years old Barrel 240 Gas, fish-tail burner Rubner 300 Gas, fish-tail burner Tweedy 25t) Gas, Welsbach burner Rubner 31 Gas, Welsbach burner Wedding 28 Gas, Welsbach burner Tweedy 60 Gas, Welsbach burner (Per cubic ftjot burned). . 565 Electricity, incandescent Rubner 14 Electricity, carbon incandescent Tweedy 10.5 Electricity, carbon incandescent Wedding 17.4 ^ " Electricity, tungsten incandescent Wedding 4 Electricity, Nernst incandescent Wedding 4.5 Electricity, arc lamp Wedding, Rubner 4.3 Electricity, arc lamp Allen 2.5 11 RADIATOR SURFACE J I Hoffman, in his Handbook for Healivg ari't Ventilaiing Engineers, ^1 /, : offers the following remarks on the calculation of radiator surface: "Experiments by numerous careful investigators have shown that the ordinary cast iron radiator located within the room and surrounded with comparatively still air, gives off heat at the rate of 1.7 B. t. u. (1.6 to 1.8, or 1.7 average) per degree difference between the temperature of the surrounding air and the average temperature of the heating medium, per sq. ft., per hour. The temperature of a steam radiator carrying pres- sures varying between 2 and 5 pounds gauge is usually taken at 220 degrees and the total transmission is approximately 1.7 x (220 — 70) = 255 B. t. u. per square foot per hour. (In exhaust steam heating systems where there is a vacuum maintained, the temperature will be under 212°. See steam tables, page 162, for temperatures corresponding to various degrees of vacuum. — H. S. B. W.) The general formula for the square feet of radia- tion is then Total B. t. u. lost from the room i)cr hour 1.7 x Temp. diff. between inside and outside of radiator. "This formula may be considered as rational and checked by years of experience and application. ]\Iany empirical formulas have been devised in an attempt to simplify, but the results are always so untrustworthy that the rules are worthless unless u.sed with that discretion which cornea only after years of practical experience." 157 COCHRANE HEATING ENCYCLOPEDIA One of the most sinijjle em])irie rules for comiiuting the size of direet ra(hators is that originated by Mr. William J. Baldwin, and is as follows: "Divide the difference between the temperature at which the room is to be kept and that of the coldest outside temperature by the difference between the temperature of the steam pipes and that at which you wish to keep the room, and the quotient will be the square feet, or fraction thereof, of radiating surface to each square foot of glass or its equivalent in wall surface." This rule does not take into account air leakage through doors, win- dows, etc., and common practice is to add 25% for buildings of good con- struction and 50% where the construction is poor. When lathed and plastered brick walls are used, it is safe to estimate that about 10 square feet of wall surface will be equivalent in cooling power to 1 sijuare foot of glass. It is common to assume about 400 heat units to be given off per sfjuare foot per hour from orilin;u'y indirect pin radiators with low pressure steam. COEFFICIENT OF TRANSMISSION IN CAST-IRON RADIATION By John R. Allen Diff. ill temp. bet. steam and B. t. u's. per s(j, ft. per liour per tlegree diff. of temp, room 2-eol. radiator 3-eol. radiator 110 1.71 1.65 120 1 . 745 1 . 695 130 1.76 1,745 140 1 . 82 1 . 79 150 1,855 1,,S35 160 1 , 895 1 . 885 170 1.93 1.93 180 1 . 965 1 . 98 190 2.00 2,025 200 2 , 04 2 , 075 210 2,075 2,12 220 2,11 2,165 230 2,15 2,215 240 2,185 2,260 250 2,22 2,31 260 2 , 265 2 , 36 158 HEATING TABLES AND DATA HEAT TRANSMISSION FROM LOW PRESSURE STEAM {By Rklschel) B.t. u. per sq. ft. per hr. per fipg. diR. Kind of Heating Surface: between steam and surrounding air Simple horizontal pipe, 1} to 4 ins. diam 2.4 to 2.7 Simple vertical pipe, 1 ^ to 4 ins. diam 2 . 5 to 2 . S Pipe coil up to 40 ins. high, outside diam. \\ ins. or over 2.3 to 2.5 Pipe coil over 40 ins. high 2 . to 2 . 3 Pipe sections of horizontal or vertical pipes, 1 to 4 rows 1.6 to 2.4 Plate heaters without ribs, 40 ins. and up 2.3to2.5 Radiators, smallest distance between elements not less than 1 inch : 1 element 2.4 2 to 6 elements 1.6 to 1.9 Ribbed heaters, up to 24 ins. high, vertical ribs: Space between at least 2 ins., rib heights 1 to 2| ins 1 . 3 to 1 . 6 Ribbed pipes with circular ribs, distance between ribs at least Ij ins 1.3 Ribbed heaters with inclined ribs, elements arranged with ribs at right angles with one another, distance between ribs at least iin 1.2 Ribbed heaters of circular cross section, lying horizontally one above another, space between ribs at least f in., 1 pipe 1.2 3 to 6 pipes, ribs partly intermeshing 8 to . 9 Ribbed heaters as above, but with oval cross section, distance between ribs at least 5 in., 1 pipe 1.4 3 to 6 pipes, not intermeshing 9 to 1 . 1 Ribbed heaters, circular or oval cross section, lying horizontally one above another, round or square cornered ribs, steam en- trance at the middle of each pipe, baffles oast in, space be- tween ribs at least | in., 1 pipe 1.2 3 to 6 pipes, not intermeshing 8 to . 9 159 COCHRANE HEATING ENCYCLOPEDIA TABLE FOR CONVERTING SQUARE FEET TO LINEAL FEET FOR DIFFERENT SIZES OF PIPE 1 equare foot of radiating surface equals 3.63 lineal feet f'pipe 2.9 ■ 1" ' 2.3 ' li" ' 2.01 " ' U" ' 1.608 ■' . 2" ' 1.329 " ' 21" ' 1.090 " , 3„ , 0.955 " ' 3i" ' 0.84S " . 4" ' 0.763 " ' it," ' 0.685 " • 5" ' 0.576 " ! ^'n \ 0.501 " 7 0.442 " ' 8" ■ 0.397 " ' 9" ' 0.355 " ' 10" ' HEAT LOSSES FROM PIPES By ir. -1/. Grosveucr CiiN\ HCTI(.)N' KMnXTlOS Nominal Outside Outer surface Box's factor (B.t.U.|)rrft.lKtll Jicrdeg.perlir. pipe diameter per ft. of B. t. u. per (HI X IV) Radn faetor diameter U. S. standard lenglli. in s J. ft. per deg for iron. in iiiclies HI inches square feet per lir ( 64)xcol. Ill (I) (II) (III) (IV) (V) (VI) 1 .405 . 106 .125 .OiiS 1 i .54 .141 .150 .090 1 8 . ri75 .177 .172 .113 i .84 .219 ^926 .204 .140 1 1.05 . 275 .870 .239 .176 1 1.315 .344 .822 . 283 .220 H 1,66 .435 .770 .334 .278 U 1.9 .497 .736 .366 .318 2 2.375 . 622 .680 . 423 .378 2-1 2 . 875 . 752 .632 .475 .481 3 3 5 .916 595 .545 .586 3i 4 1 . 005 .574 578 .643 4 4.5 1,178 .572 .622 .754 4h 5 1 , 309 .544 .713 .838 5 5.563 1 , 456 . 533 .776 .932 6 6.625 1 733 .515 .894 1.109 7 7.625 1 , 906 . 501 1. 1.277 8 S . 625 2 , 257 .491 1.105 1.444 9 9 . 625 2,519 .484 1,218 1.612 10 10 75 2,817 .478 1 , 345 1 . 803 12 12,75 3 333 .469 1 , 56 2.133 IS 18 4,717 . 455 2,13 3.019 24 24 6 , 289 .447 2.81 4 . 025 36 36 9,434 .438 4.13 6 . 038 48 48 12.5()3 .434 5.45 8.040 160 HEATING TABLES AND DATA PIPE COVERING The effectiveness of different forms of pipe covering was determined in a series of experiments made at the University of Michigan and re- ported in Prof. John R. Allen's Nalcs on Healiiifi and y,:i dilation. The figm-es are given in the following tal)le. Hair felt is shown to be the best non-conductor. Hair felt and wool felt are satisfactory for pressures under five lbs. gauge, but should not be used for higher pressures as the heat will char and break them down. Material of Co^■e^ing Moidding Coverings : Asbestos Magnesia Magnesia and A.sbestos Asbestos and AA'ool Felt Wool Felt Wool Felt and Iron with Air Space Sectional Coverings: Mineral Wool Asbestos Sponge Asbestos Felt Hair Felt >\'on-Sectional Coverings : Two Layers Asbestos Paper .388 Two Layers Asbestos Paper, one in. Hair Felt and one thickness Canvas . 070 V -3 1 o > . ; 1 "c^5 . -M ■Jj . E i != ¥t o o es ■^OP3 n ^.rj J aPn _&y._2_ HO ca" 0, «-?5_ . 14.T ..319 1 . 23 136 . 803 .119 .224 . 94 166 .915 .12.5 .300 1.12 US .879 .190 .22S 1.12 102 .910 .117 .234 1.16 110 .904 .134 .269 12.5 .828 .097 .193 .94 91 .952 .105 .220 1.12 102 .920 .100 .217 1.3.5 94 .923 .080 .186 1.4.5 75 .960 .777 .150 364 .263 1.000 HEAT TRANSMISSION FOR VARYING THICK- NESSES OF COVERING The following tabic shows the relative effectiveness of different tliick- nesses of wool felt covering. Thir'knti'ss of co\"eiing C'tjridr-nsation per .sq, Katio of condensation B. t. u's. tran.sniitted in incfie.s ft. per hour in lb,s. C'o\-ered to Bare pipe. per sr4. ft. per liour. 1! .120 .117 .107 .099 .087 .078 .281 .255 .231 .219 .191 .19 167 163 149 138 121 108 , Ordinarih', one inch covering is .sufficiently heavy for building work, but for tunnel work and all work where the heat loss from the i)i])es is entirely lost and does not enter tlic building, it is economy to use covering two inches thick. 161 COCHRANE HEATING ENCYCLOPEDIA PROPERTIES OF SATURATED STEAM From Slcmn Tahles of Marks ,i;- Deris, mpi/i i//hti(J . Reproiliired hi/ i)er)nissijin of (fit: oiilhors and if the imbli^Jirrs., LaiKjnianx, Grevn tt" ('<>. Entropy ^':HMUl^l Sp. \o\. Scnsiblo Heat Latent Temp. (Rfferred cu. ft. of the liquid heut of Fahr. to ;i 30 in. per lb. at)Ove ^2° F evap. \\"ater (t) barometer) (v or s) (h or q) iLor r) In or ei II, \ Ltp. 32° 29.X196 3294. 0.00 1073.4 0.0000 2.1832 3.5° 29.7966 2938. 3.02 1074.7 0.0062 2.1666 40° 29.7.523 243S. 8.0.5 106,s.9 0.0162 2.1394 45° 29.6998 2033. 13.07 106(5.1 0.0262 2.1127 50° 29,6375 1702. 18.0,s 10()3.3 0.0361 2.0865 55° 29.5643 1430. 23.08 1060,6 0.0459 2.0609 60° 29.478 1208. 28.(),s 1057.8 0.05.55 2.03.58 65° 29,378 1024. 33,07 1055.0 0.06.5O 2.0110 70° 29.261 871. 38.06 1052.3 0.0745 1.9868 75° 29.127 743. 43.05 1049..5 0.0840 1.9631 80° 28.971 636.8 48.03 1046.7 0.0932 1.9398 85° 28.791 545.9 53.02 1044.0 0.1023 1.9169 90° 28.583 469.3 58.00 1041.2 0.1114 1.8944 95° 28.345 405.0 62.99 1038.4 0.1205 1.8723 100° 28.074 3.50.8 67.97 1035.6 0.1295 1.8505 105° 27.764 304.7 72.95 1032,8 0,1383 1.8292 110° 27.411 265.5 77.94 1C30.0 0.1471 1.8082 115° 27.013 231.9 82.92 1027.2 0.1.5.59 1.7876 120° 26..562 203.1 87.91 1024.4 0.1645 1.7674 125° 26.052 178.4 92.90 1021.6 0.1730 1.7475 130° 25.48 157.1 97.89 101S.8 0.1816 1.7279 135° 24.84 138.7 102. ,88 1016.0 0.1900 1.7086 140° 24.12 122.8 107.87 1013.1 0.19.84 1.6896 145° 23.33 109.0 112.86 1010.3 0.2067 1.6709 150° 22.43 9().9 117.,86 1007.4 0.2149 1.6525 1.55° 21.45 86.4 122.86 1004.5 0.2231 1.6344 160° 20.35 77.2 127.,S6 1001.6 0.2311 1.6165 165° 19.14 69.1 132. ,S6 998.7 0.2391 1.59,S9 170° 17.80 175° 16.33 180° 14.71 185° 12.93 190° 10.98 195° 8.85 200° 6.53 205° 4.00 210° 1.24 212° 0.08 162 (i2.0 137.87 995.8 0.2470 1.5816 .55.7 142.,S7 992.9 0.25.50 1.5645 50.15 147.,S8 989.9 0.2628 1..5476 45.25 152.,S9 986.9 0.2706 1.5310 40.91 157.91 983.9 0.2783 1.5146 37.04 162.92 980.9 0.2,860 1.4984 33.60 167.94 977.8 0.2937 1 .4.S24 30.53 172.96 974.7 0.3012 1.4666 27., SO 177.99 071.6 0.3087 1.4510 26.79 1.80.00 970.4 0.3118 1.4447 HEATING TABLES AND DATA PROPERTIES OF Temp, Fahr. (t) Pressure lbs. per SC]. ID. gauge 212° 215° 220° 225° 00.00 00.90 2.49 4,21 230° 235° 240° 245° 6,07 8,09 10,27 12,61 250° 255° 260° 265° 15.12 17.83 20.72 23.82 270° 275° 280° 285° 27.15 30.70 34.48 38.54 290° 295° 300° 305° 42.85 47.43 52.30 57,47 310° 315° 320° 325° 62,97 68,79 74,93 81,45 330° 335° 340° 342° 88,30 95.6 103.3 106.5 344° 346° 348° 350° 109.7 113.0 116.4 119.9 352° 354° 356° 358° 123.4 127.0 130.7 134.4 360° 362° 364° 366° 138.3 142.2 146.1 150,2 ■ SATURATED STEAM — Continued .Sp. Vol. cu. ft. per Ih. Iv or si Heat of tlie liqtiid (h or q) Latent heat of evap, (Lorr) Enti ropy Water (11 or e) Evap Vt^t/ 26.79 25.35 23.15 21.17 180.00 183.0 188.1 193.1 970,4 968,4 965,2 962,0 0.3118 0.3163 0.3238 0.3312 1.4447 1.4354 1.4199 1.4052 19.39 17.78 16,32 15.01 198.2 203.2 208.3 213.4 958,7 955,4 9.52,1 948,7 0.3384 0.3458 0.3531 0.3603 1.3905 1.37.54 1.3607 1.3465 13.82 12.74 11.76 10.87 21S.5 223.5 228.6 233.7 945,3 941,9 938,4 934,9 0.3675 0.3747 0.3818 0.3888 1.3321 1.3179 1.3040 1.2903 10,06 9,32 8,64 8,02 238.8 243.9 249.0 2.54.2 931,4 927,9 924,3 920,5 0.3959 0.4029 0.4098 0.4168 1.2766 1.2629 1.2496 1.2363 7,46 6,94 6,46 6,03 259.3 264.4 269.0 274.7 916,9 913.2 909.5 905.7 0.4235 0.4304 0.4371 0.4439 1.2232 1.2101 1.1972 1.1844 5,62 5,26 4,91 4,60 279.9 285.0 290.2 295,4 - 901.9 898.0 894.2 890.2 0.4.507 0.4573 0,4640 0,4705 1.1717 1.1592 1.1468 1.1346 4,306 4,035 3,787 3.692 300,6 305,8 311,0 313,0 886.3 882,3 878,3 876,7 0,4771 0,4837 0,4902 0,4928 1.1225 1.1103 1,0984 1,0937 3.600 3.511 3.425 3.342 315,1 317,2 319.3 321.4 875,1 873,4 871,8 870,1 0.4954 0.4980 0.5006 0.5032 1,0889 1,0841 1,0794 1,0748 3.261 3.182 3.105 3.030 323.5 325.6 327.7 329.8 868.5 866.8 865,2 863,5 0.5058 0.5084 0.5110 0.5136 1,0700 1,0653 1,0607 1,0560 2.957 2.887 2.820 2.754 331,9 334,0 336,1 338,2 .861,8 860.2 858.5 856.8 0.5162 0.5187 0.5213 0.5238 1.0514 1.0468 1.0422 1.0377 163 COCHRANE HEATING ENCYCLOPEDIA PROPERTIES OF SATURATED STEAM Temp. Fahr. (t) 368° 370° 372° 374° 376° 378° 3S0° 382° 384° 386° 388° 390° 392° 394° 396° 398° 400° 410° Pressure lbs. per sq. in. gauge 154.3 158.6 162.9 167.2 171.7 176.2 180.9 185. 6 190.4 195.3 200.4 205.5 210.7 216.0 221.4 226,8 232.4 261.6 Sp. Vol. ru ft per lb. (v etr 3) 2.690 2.627 2.567 2.508 2.450 2.394 2.340 2.287 2.236 2.186 2.137 2.089 2,043 1 .999 1.955 1.913 1,872 1,679 Heat (if the liquid (h or (|) 340.3 342.4 344.5 346.6 348.7 350.8 352.9 355.0 357.2 359.3 361.4 363.5 365.6 367.7 369.9 372.0 374.1 384.7 T.atcnt heat of ei-ap, (I,orrl 855.1 853.4 851,7 850,0 848,3 846,5 844,8 843.1 ,841.3 839.6 837.8 S36.1 834.3 832.5 830.7 829.0 827.2 818.2 CONTINUED Entropy Evap- 1.0332 1.0286 1.0240 1.0194 0.5263 0.5289 0.5314 0.5340 0.5364 0.5389 0.5413 0.5439 0.5464 0.5488 0.5513 0.5539 0.5565 0.5590 0.5615 0.5639 0.5663 0.5786 1.0150 1.0105 1.0060 1.0015 0.9971 0.9928 0.9884 0.9840 0.9796 0.9752 0.9708 0.9665 0.9623 0.9409 SUPPLY MAINS The size of supply mains may be estimated from charts on pages 165, 166 and 167, talien from German tables prepared by E. Ritt and published in Berechnung der Rohrlciliiiigiii hei Niederdrmkdampfheizurige?i. The tables are based on a derivation of Fischer's Equation. The abscissae represent pounds of steam flowing jxt hoiu', and ordinates the pressure loss in pounds per square meh ]>er 100 running feet. The charts are based on an initial prcssin'o of 14, 91-! llis. ])er sq. in. absolute, or 0.23 lb. gauge. By means of the table on page 168 we can figure pipe sizes where other initial pressures are used. For example supjiose we must supply 7,000 lbs. steam per hour to the heating system, which is at a distance of 200 feet. The initial pressure is 2 lbs. gauge and we will allow for a 4 lb. drop. Referring to the table on page 168 we multiply 7,000 by 1.06=7,420. 4=2=2 lbs. presstn-e drop per 100 feet. Now referring to the chart on page 167, the intersection of (q'diuatc 2 and al)scissa 7,420 lies miilway between the and 7 inch pipe. It would be safe to use 6 inch pipe for this service, as tlie sizes given are lilx'ral. As snudl |npes as possible should be used, due to lower cost antl less ratliation. 164 HEATING TABLES AND DATA i ' ' 1 1 ! \ \ \ \ \ v \ s \ ""^v X \ \ ^\ \ ^\^ V \.^ V ^. ^^ IT ^v X^ "~^-^ \ A K ^^-^-^ "^Jl ~~~~"~-~- "^^ it ^^^^5:^-5 _ ^ ^ -- -=^i IKjO 100 PRESSURE LOSS IN LBS. PER SQ. IN. PER 100 RUNNING FEET Pressure Drop in Sleani Pipes. Low Pressure Steam. 165 COCHRANE HEATING ENCYCLOPEDIA '-s \ \ \ \ \, \ \ N, \ r \ \ \ \ \, N \ \ N N \ \ \ X \, \, r \ N \ \ \ ^ \ \ \ \ ■N N \ s V \ \ *. r ■^ N \ \ \ -.7^ -^ s \ \ \ s ■-^ ^ \ N \ \ \ \ \ \ ^ \ \ N \ f^^ ^ ^ ■^ \ \ \ \ ^ \ N, \ \^ "^ \ \ \ \ ■~-- ^ \ \' \ ^ \ \ \\ •\ X \ 1 \ \| 1 7500 70(0 600O 4500 •1000 3500 !■■ PRESSURE LOSS IN LBS. PER SQ. IN. PER 100 RUNNING FEET Prfssitre Drop in Sleam Pipes. Low Pressure Steam- 166 HEATING TABLES AND DATA sure is :\iu tipl ylhs. ,.f steam by 12 Ins. \m man. .78 9 Ins. '■ .84 6 Ins. .90 3 Ins. .95 0.2::! I.b. Gauge, 1.00 1 U.S. l.fK! 2 Lbs. 1 or, 3 T.bs. l.U'.l 4 Lbs. 1.11 5 Lb~ 1 .14 053 - S5. 3 -'^^'Z ^: 1,4 oao 0009 oUoQ OOOOf " ~^'^^5"r ~- -_ ^-^^ -3^ "M- OOQSa z aoooe' .0, 5 -^ "Si "fci. 168 1 i HEATING TABLES AND DATA The drop in pressure is usually taken as 1 lb, per 300 feet uf steam travel. (Thompson.) There is also another con.sideration in determininff the size of mams. They must be of sufficient size to allow of tree circulation. This is the principal consideration in smaller buildings, while the drop in pressure IS of particular importance in the design of central heating systems. Prof. John R. Allen gives the following table for proportioning pipe sizes with a given amoimt of radiation: SIZES OF MAINS FOR DIFFERENT AMOUNTS OF RADIATION Xo^ofSq. Ftof Steam Main Stoam Main Steam Riser Steam Riser Radiation on the Single Pipe Two Pipe Single Pipe Two Pipe Mam or Riser S.vstem System System System 30 li" U" li" li" 100 2 li li li 150 2 U 2 li 200 2i 2 2i 2 250 2i 2 2i 2 300 3 2i 3 2i 400 3i 3 3 2i 500 3i 3 3 3 600 3i 3i SOO 4 3i 1000 4i 4 1500 4i 4 2000 5 4i 3000 6 5 4000 7 6 6000 8 7 The steam supply of the radiator should never be less than 1 inch. Supply connections with radiators and coils in the two-pipe vacuum system of steam heating are commonly | inch up to 50 sq. ft., 1 inch for 51 to 100 sq. ft., li inches for 101 to 190 sq. ft., li inches for 191 to 310 sq. ft., 2 inches for 311 to 670 sq. ft., 2i inches for 671 to 1250 sq. ft., and 3 inches for 1251 to 2040 sq. ft. It will be noted that these are considerably smaller than pipe connections with ordinary low pressure heating systems. (Snow.) Snow gives the following steam velocities as safe for the pipe sizes indicated: l\ inches, li inches, up to 50 feet per second; 4 inches, 5 inches, 6 inches, 90 feet per second; 6 inches and up, 100 feet per second. It has been found that a radiator working under ordinary conditions, with steam at atmospheric pressure and 0° outside temperature will condense about 0.3 pounds of steam per square foot of radiating surface per hour. RETURN PIPES Professor Carpenter says: "The size of return pipes, if figured from the actual volume of water to be carried back, would be smaller than is safe to use, largely because 169 COCHRANE HEATING ENCYCLOPEDIA nf air which is contaiiicil in the steam |)i|ies. When the steam main is large, the diameter of the return pipe will prove satisfactory if taken one size less than one-half that of the steam pipe; but if the steam main is small, for instance five inches or less, the return ]iipe should be but one or two sizes smaller. The return pipe shoulil never be less than one inch to sectu'e satisfactory results. The following table suggests sizes of returns wliich will iii'ove satisfactory for sizes of main steam-pipes as given: Diani. .'^team Pipe ]i 2 2i 3 3| 4 .5 6 S 9 10 12 Diam. Re;urn Pipe 1^ H 1| 2 2| 2i 3 3^ 4 4^ 41 5 RELIEFS AND DRIP PIPES Again ((uoting Professor Carpenter: "The size of drip jiii^es necessary to convey the water of condensa- tion from a steam main to a return cannot be obtained by computation, as there is much uncertainty regarding the amount of water that will flow through imder the conditions wliich exist. The wi'iter would recom- mend the employment of the following sizes of dri]) pi])es as ample for usual conditions: DIAMETER OF DRIP PIPES FOR STEAM MAINS OF VARIOUS LENGTHS I.«^ngth of Steam Main in feet O-IUO 100-200 200-400 400-600 Diameter of Drip Pipe in inches D ianie ter of Sleani .Mai 11, Iiiehes 0-2 3 4 3 * 3 I 1 3 1 1 li 1 u li n li U 6 1 AIR PIPES AND VALVES Air valves, properly placed, are very important parts of a steam piping system. ( )ne shoukl be placed wherever air is liable to accumulate in either steam or return mains. The tendency of air is to remam in the bottom half of tlic ])ipe, the hot steam and vapor being at the top. Therefore it is well to iiin the air release pipe tlown to the bottom of the main. In air line systems the air pipe should not be less than I inch between the air vah'c and the first fitting, where it should increase to k inch pipe Xo air riser should be less than i inch, and where the air riser extends above the second floor or is connected to more than two air valves should not be less than j inch. The horizontal air main should be run on the basement ceiling and need not be larger than 1 inch except in cases of extreme length, where it should be Ij inches. (Snow.) 170 HEATING TABLES AND DATA SQUARE FEET OF DIRECT RADIATING SURFACE CARED FOR BY VARIOUS SIZES OF VACUUM PUMPS Bii C. L. HnhhnriL Size of Pump. Square feet of Radiation. 3,000 7,000 15,000 30,000 40,000 60,000 4 bv .5 by 5 4 bv 6 bv t 5-i by 8 by 7 6 bv 9bv 10 6 bv 10 bv 12 8 bV 12 bV 12 EQUIVALENT STRAIGHT PIPE FOR GLOBE VALVES, BENDS AND ELBOWS Bij Sidney C. Carpenter. This table is calculated from the following formulae, taken from the catalog of the IngersoU-Sergeant Drill Co. : lUd 1 3^ d B: ;A d= Diameter of pipe in inches. A^ Length, in inches, of pipe equivalent to globe valve. B= Length, in inches, of pipe equivalent to bends and elbows Pipe Diameter. 1 u u 2 ■2i 3 4 ^ 5 6 7 10 12 14 16 18 20 22 24 26 28 30 EQui\'alent Straight Pipe Due to Globe Valves. Bends and Elbow.^ Feet. Inches. Feet. Indies. 2 1 1 .5 3 1 2 1 4 2 2 10 6 9 4 6 9 9 12 11 16 5 20 23 9 27 7 3.5 8 44 ,52 5 61 1 69 10 87 8 105 6 124 1 142 6 161 180 2 197 10 216 8 230 6 6 8 8 10 11 13 4 15 10 18 5 23 9 29 4 34 11 40 9 46 7 58 6 70 4 82 9 95 107 4 120 1 131 11 144 5 153 4 2.54 169 171 COCHRANE HEATING ENCYCLOPEDIA COMPARATIVE CARRYING CAPACITIES OF DIFFERENT SIZE PIPES L)iani, Capacity Ins Faft,.r \ 2 3 4 5 1 10 li 20 n 30 2 60 2i 110 Diam. Capacity Ins. Factor 3 175 3i 260 4 380 5 650 6 1050 7 1600 8 2250 E.xuiiiple: To get size jtipe to serve a J inch pipe and a 1 inch pipe: J inch equals 5 1 inch eq vials 10 15 etiuals \\ inch. RADIATING SURFACE AND SIZES OF STEAM MAINS Fri.in Ciilnloij of I'nsilirc Differeiitinl Sijsleiii, By Jds. A. Doinidly. In designing a hetiting apparatus the factor of first importance is that the radiating surfaces should be ample to heat the Ijuildmg. The heating effect can be reduced by throttling the sujiply, but it is very un- desirable to raise tlie ))rcssiu'c in order to obtain ailditionttl heating effect. Xo system of circulation can do more thtm keep the railiating surfaces at the steam tempendure, and if the heating surface is insufficient in fiuantity no other remedy exi.sts except to increase it. In almost all formulas for figuring radiating surfaces the number of changes of air per hour for wiiich allowance should be made is a troublesome factor. Where nreehanical ventilation is provided by the plenum system it may be figured with com- parative accuracy, but when direct radiation is used the amount of natural ventilation or leakage of air into the building is a subject on which individual judgment and exiierieiice must be used. The most that can lie said is that it varies with the exposure and is seldom below one change of air ])er hour and should not be above three or four changes in the most extreme types of buildings. Next in importance are the sizes of steam mains and couneclions. In all steam heating apparatus, as the steam leaves the source of supply, its temperature and its pressure are constantly reduced by the friction of the flow in the steam main. This drop in pressure and temperature may be kept at a minimum amount by the use of standard and jiropcr sizes of pipe. All}' material reduction from the.se standard sizes will cau.se a loss of efficiency in tlic circulation and in the radiating surftiees which is not offset by the saving in first cost, no matter what .system is used. 172 HEATING TABLES AND DATA The following table is given in order that the selection of steam main , t^ sizes may be made for any desired drop in pressure, it being borne in mind '' ^' that proper allowance must be made for the condensing effect of steam and return mains and for the amount of steam condensed b\' jet water at the f - vacuum jiump (if any jet water is used) in figurnig the tdtal flow through the steam main. Also that the friction of elbows, etc., under ordinary conditions will sometimes increase the drop in jjressure to twice that given for straight pipe. (See table, page 174.) f STANDARD SIZES OF STEAM PIPES The standard of steam mam sizes recommended is tliat in winch the maximum velocity permissible will not require more than one ounce droji I in pressure for one hundred feet run in straight pipe to maintain it. It may be advisable to use a lower velocity in many cases, but it is believed • ^ that this velocity can not be exceeded with the best results. ^ All steam mains, risers and radiator connections within buildings of ordmary size may usually be laid out with this maximum velocity, ^\■here buildings are unusually large and the length of run, in consequence, longer than ordinary, or where the steam distribution is carried long distances between buildings, the proportioning of steam mains is a .separate problem. I I Where the distribution is made at high pressure, and the pressure is re- I f duced for use at each building, a greater drop than that suggested may be used between the buildings. Where exhaust steam or steam at quite low pressure is to be distributed over large areas, a lower velocity than that sug- gested may be advisable and even necessary. But within buildings of ordi- narj- size, the standard as above suggested may be ver}* closel}- adhered to. SIZES OF RETURN MAINS Return mams have usually been considered as having a certain pro- portionate size to the corresponding steam main, but the amount fif radia- tion which is supplied by the steam main, irrespective of its size, or the amount of radiation which is drained, should determine the size of there- turn main. Thus, a steam main which was supplying an unusually large amount of radiation would need a comparatively larger return ])ipe than one which was supplying a smaller amount. If wc consifler the sizes of return mains witliin the buildings, and leave the question of returns which run long distances for investigation as a separate problem, as in the case of steam mains, the subject is very much ' simpKfied. It is desirable that the drop in pressure shall be the same in '' '' both the steam and return main, namely, 1 oz. to 100 ft. in straight pipe, and if it is to be a wet return, the corresponding rating will be proportional ' / to the square root of the comparative density between steam and water. '/, As water at 212° F. is about 1,600 times as heavy as steam at atmospheric pressure, a wet return pipe will carry 40 times as much radiation as the steam rating of the same size pipe with the same pnssure lo.ss from friction. Dry return pipes for gravity systems or those which are run aljove the water line of the boiler or return tank, must not only be large enough to carry back all the water of condensation, but the steam necessary to supply the heat radiating effect of the returns themselves. Therefore, in figuring 173 COCHRANE HEATING ENCYCLOPEDIA z o H < a < DC h O u QC o L. (/) z 05 to a ■J o u I— t H o cn CO O :3 to a u .-H N t-l bD C ■? O ?)AI^T!JBdLU03 u,["-a dojp 1 — ^ 30 o c-i ^ t-l o c-i to <^ tr ■X -1- c-i -H -t r- fM ^ "2 ~o o =, o o o o o o o o o r~ ^ CT- O CO CO .-H — C^ rO "O t— 00 (M C. - — C< CI dojp I u.p^a doi[» ■Z() Cloj[) dojp u.pcH dt)jp ■ZQ Oi C^ C-l CC "O "-S ^o o — t- a-- O O c: O Oi m 30 30 ■* — C-l CO r- to 5* Sts dojp r c-j CO -H CO CO OO >— lO^oo 'lOcO'-Hcc t>-:Dio doip ■ZQ dojp Z() — — c-j *&^ ^ - ~~ — 1 — ;_ \ ^ .^ fc^S ■" ~ — . .-^ ^ " — I;;:: '^ ^ i!^ "~— 1 - ,- ,- _- ., ,- J /^O /JO Z-,^ ,^^ .c^ .... .ju rrr iim, Imfia/ SfearT? Pressure /Jbso/u/e. Diagram Slioimng Steam Covsumpiiori of a Perfect Steam Engine ivticn Receiving Steam al Different Pressnres and Exhausting Against Dif- ferent Back Pressures. The steam consumption of actual engines is affected in about the sa7ne proportion. 180 HEATING TABLES AND DATA HOW TO MAKE UP FOR BACK PRESSURE If back pressure is carried on an engine, the decrease in power output or the increase in steam consumption may be offset by an increase in boiler pressure. The increase must however be greater than the increase in back pressure, since the latter acts throughout the stroke, whereas the full boiler pressure acts during one-quarter, one-third or other fraction of the stroke, depending on the cut-off of the engine. For instance an increase in back pressure of 5 lbs. on an engine with cut-off at i stroke will require an increase in boiler pressure of about 8 lbs. to give the same power output. This means only a very slight increase of fuel consumption, however, as the total heat necessary to make steam is not at all in proportion to the pres- sure increase. It will require only 1/SOO more coal to generate steam at 110 lbs. pressure than at 100 lbs. r\ ^ — 50 3 1-30 ^ ir \ \ ? "^ X. d- . \ N ■2 ^ ■v^ ^ \. ^■v. "^v^ ^ J 2 a 6 7 Prcifure — Pounds Gaugt ( 1 1 Schedule of Skam Pressures lo he (_'arrieuililings, as regards continuity of heating, are radically different. TAKING STEAM FROM INTERMEDIATE RECEIVER FOR HEATING By C. T. Main and F. J[. Gunhy. The saving from using the exliaust of a non-condensing engine which would otherwise go to waste is large, because there is no additional steam required for the engine, unless the back pressure is increased. Any use of the steam is nearly all clear profit, and if all of it is used, the only part left to charge to power is the difference in B. t. u. due to the difference in pres- sure, and the condensation in the engine cjdinder, jackets, etc. The use of large non-condensing engines for producing power, except in special cases, is becoming comparatively rare, but the use of steam from the re- ceiver of a cross-compound condensing engine for manufacturing purposes and for heating, etc, is a very common practice. 184 Lbs, of Cnal per Indi- cated H. P. per Hour, All Coal Charged to Power Net lbs, of Coal per indicated H, P, per Hr, after Deducting for Exhaust Steam Used 1,75 1-75 2,06 1,50 2,38 1,25 2,69 1.00 3,00 ,75 HEATING TABLES AND DATA The table given below shows the amount of coal chargeable to i)ower when certain percentages of the steam entering the high-pressure cyUnder were taken out of the receiver. This table takes into consideration the effects on the economy of the engine of not passing all of the steam into the low-pressure cylinder, cylintier condensation, and the like. Per Cent, of Exhaust 8teani used for Heating Purposes 25 50 75 100 It the mill did not obtain its power from steam so that it could use the low-pressure steam of the plant for manufacturing, it would have to main- tain a boiler plant of sufficient size to produce an equivalent amount of steam to that bled out of the receiver, so that only the amount of B.t.u.in coal, or its equivalent, representing the amount of work done by the engine, or the losses due to the presence of the engine, is chargeable to power. The cost of generating the rest of the steam is chargeable to the manufacturing processes, etc. By cost of generating steam we mean the total cost, in- cluding coal, labor, fixed charges and supphes of all kinds for the boiler plant. The cost in the engine room, of course, does not vary with the bleeding of steam except pos.sibly in some very unusual cases. HOT BLAST HEATING By Wnrrrn H. Miller. In figuring the size of heater plants for any given shop, the heater companies use the following for ordinary shops of about 75 per cent, window area. Cubical contents of building divided by 150 gives lineal feet of 1-inch heater-coil pipe required, using live and exhaust steam. Divide the lineal feet of heater-coil pipe bj' 70 and you get the boiler horsepower required for heating, and the fan engine will be either 3x4, 4x4, 5x5, 6x6, or 7x7 inches, depending upon which engine comes nearest to halt of the boiler horsepower required to run the heater. There are no other sizes of engines used. The above guarantees 60 degrees inside temperature at degrees outside, allowing 4 pounds back prcs.surc for the exhaust. LIVE VS. EXHAUST STEAM HEATING In the Revue de Meeaniqiie, February 29th, 1912, M. Lecuir gives some interesting comparisons of various systems of steam heating in con- nection with steam power plants from an economic point of view. In cases where the pressure in the heating main is less than that in the boiler any one of the following three systems may be used: 185 COCHRANE HEATING ENCYCLOPEDIA Heat hiihiiicr of o f:iiiijlc ci/liniler 201) H . P. engine, ixhnusi sivnm healing. (a) High pressviie steam passed tlirougb a reducing valve. (hi Tlie installation of a separate boiler carrj'ing the pressure re- quired for tlie heatuig system. This complicates the service in the boiler room and involves large losses in fuel, but is, on the whole, preferable to the first solution. (c) By the use of exhaust steam. The above chart represents the lieat balance of a single cyhnder 200 H. P. engine installed in a certain building. The heat necessary for heating is 1,00(1, .500 calories (say 4,000,000 B.t.. u's.) which is just about supplied by the exhaust from the engine. Ordinarily it would lie more iirofitable to use ] or !, of this exhaust to heat the boiler feed water and supplement with low i>ressure steam used for heating by a small amount of high ])ressure steam through a reducing valve. M. Lecuir states that if the steam re- quired for heating had to be produced separately with coal having a heat value of 7000 ealoi-i<'s ))cr kilogram (say 12,000 B.t. u's. per lb.) aljout 240 pounds of coal per hour would have to be consumed. The cliai't on i)age ]S7 shows the heat balance of a tandem coni]iound engine with heating by live steam. The total economy is consiileralily less satisfai'tory than in the ease of the single cylinder engine. 'Jlie I'elation between the type of heating and the machine used is ex- ])ressed as follows according to the author: If the heating plant requires sleani in amount equal or slightly exceeding that furnished by the engines, at a ]ii cssure oOO to (iOO grams (4.2.j to 8.5 lb. per sq. in.) above atmospheric, a single-cylinder engine is advisable, because this pressure corresponds to the final jiressure for a diagram showing the best economic utilization of 186 HEATING TABLES AND DATA Losses by tMof,nl 1 1 1 1 1 1 1 j 1 1 1 1 ■ 1 1 1 [ , r — —•- '" ^^ J \ N / ' 6J i." '^ 7 k T ^~i7 ^ / k " ^^'!s — / ,§ ^^^ z ^ «^ -h -r + ■< <^ / ^> ^^ ^ ^ ^ " ?^' Z It rr\ v"^ ^ ^ ^^2t y'^ IN it A ^r*;^ ■ v ^ ^^ -PlC^ 2 ^^1^ y m^- i: '-f^- ^ -^'X- yC 1 v^X^i^ ' ^7 Ip^J,^ ^^ ^^^ 7" V tS ' Q ^ ^ ,'- \ JK- % T d? V- ^ x\\ a J- " " " iT^ \J^^ IT ^\W ^"S ^ \,^\Jt^ ^ ZIlC^^ 5 ^ ^^^4= Ji \ ■■ 1 ^'- ^ ■"^ ^ : V M-'.—'^- — 1 ' 1 1 1 1 M 1 ^ '"S^ lot I 03 lot 20 40 60 100 no 140 160 ISO 100 120 UO 160 ISO 300 no 3A0 SbO }bO 400 Specific Weight and Relative Volume of Water at Different Temperatures. 195 COCHRANE HEATING ENCYCLOPEDIA hi U. O UJ si < u h£ LJ < u ^ u. u. L.IJ Oh- 2o IZ o III < 1£ ZUJ O z o z o o (L X < u. I >-o CQ (f) O Q < hi z I 0) o U[ peaq JO ssoq CO lO GO CI 'Xi -t CI ^ GO I %0B} oiqnj laaj JO SSO'I CJ I-- CO >— ' -— I CI X' O Cl lO I- X ' CI CO CO -+"0:0 Xj O o ' '■O) a: CI to 'X --H -f X ,— I ■ CI CO "O <:o r-- a; o --H CO ■ ^ ir^ tri O' f^l -— ' f- -c cr. --^ "^' o (X cr- -rfi o^ci -t^:cai ----foo 1- ^ o en ci '-^ 'j:. '-0 CO '— ' o 'X -— I Cl CO -t^ LO i-O O lO -x t~ lO CO 'O r- X <:O00 t^ CO CO C) »o o CI -t" CO LO -^ .X -t CO CO I tO' LQ LO -H --H Ol CI CI -o r^ a; o o O CI CO ajnaiiu jad 153J ui pBai{ JO SSO'^ O Oi t^ '^ ^ >o ' -H -- X' lO CO o a: -t 00 CO X CO I l-H T-H CJ C^ CO t- CO ^ t^Cl f- CO -^ -Tt^ OiCl "T^ -^ OJ CO l>- C3 ^ IcO O '-I 00 o CD t^ Oi ' •-( C I -^ 'X: 'O; >— ' o;nuitu jad ■^aaj aiqii J 10 4 15 7 20 9 26 2 31 4 36 . 6 41 9 47.2 52 4 ui p^aq JO sso'x .459 .980 1 70 2 52 3 54 4.70 6 04 7 60 9.17 ■ C CC ^ CO en o ro CTj CO -^ o Ol CO w ^ c -t< ^ -^ O C3 O T-H CO »0 'X' --^ lO o V) a: u 0. U) CD a < OJ ■* 'O IJ CO Oi C-l X Ca (M CO |, O^ CO ^ aiTiniuijad CO CO 00 ^33J ^!qT13 LO 'X ^ CO »^''J CO -f -^ UI pcaq Ol X -j3 CO o t^ CO -f t^ CO CO ^ --^ T-H 00 o ',-H CO CO O^ (M t^ CO r^ fM Oi CO o o <0 ^ O^ OJ Ul u z 4 Ol 00 — -Jj c oi -r laaj UI p>:aq JO sycx 1.09 2.32 4 . 08 6 02 8 46 11 25 14 43 17.96 21.88 •^ l~ CO O 00 .~ uo. O^ 2 54 3.17 3 86 puooas J ad jaaj u[ i^jiJoia^Y 0^ CO -^ LO. CO 1^ rja ~. o 01 CO -t LO o r^ 00 C3) O 196 HEATING TABLES AND DATA PIPING DETAILS Pitch— Hot water piping should be pitched towards the heating medium in both flow and return mains. The pitch shoul(1 not be less than one inch in ten feet and a greater pitch than this is desirable. Sup]iort.s — The piping should be supported the same as steam pipes with supports about every ten feet. An- — All radiators and high points in the main whcie air might collect should be provided with air valves. An accumulation of air in the j^ipe will hinder the circulation. Branches — Connections supplying radiators below the level of the mains should come off the bottom of the main to prevent air accumulating and seahng the pipe. Expansion — Provision must be made for expansion of pipes due to changes in temperature, the same as in the case of steam heating. LOW-SPEED CENTRIFUGAL HOT WATER CIRCULATING PUMP CAPACITIES By C. L. Hubbard. Gallons per Size of Diam. of Revolutions per minute min. at 16 Discharge inches Impeller inches ft. head* 16 ft. head 20 ft. head 3(1 ft head 40 ft. head 100 2 18 460 510 620 710 240 3 oo 380 420 510 580 430 4 26 310 340 410 460 730 5 29 280 290 350 400 1000 6 32 240 260 320 360 1400 7 34 220 250 300 340 1800 8 36 210 240 280 320 HIGH-SPEED CENTRIFUGAL PU M P CAPACITIES if Gallons per Size of Diam. of Revolutions per minute min. at 12 Discharge, inches Impeller inches ft. head* 12 ft. head 20 ft. head 30 ft. head 40 ft. head 100 2 8 930 1190 1430 1630 240 3 9 810 1020 1220 1400 430 4 10 690 870 1050 1190 730 5 11 610 760 910 1030 1000 6 12 570 710 840 960 1400 7 14 490 610 720 820 1800 8 16 420 520 630 710 *Delivery increases directly a-< the speed. The horsepower for driving the pump is computed by the equation: „ „ H • G X 8.3 . , . , H=pressure head, in feet, pumped against. G=gallons pumped per minute. E=efficiency of pump, commonly taken as 0.50 in this class of work. 197 198 / / HEATING TABLES AND DATA ALLOWANCE TO BE MADE FOR FRICTION IN HOT WATER HEATING SYSTEMS Thp chnrt on page 198, from Meier's "Mechanics of Healing and Venli- laling," shows the loss of head b>' friction encountered when water flows at different velocities through pipes of various diameters, also the head lost in radiators, elbows, etc. The upper row of figures at the base of the chart indicates the amount of water to be circulated, in thousands of pounds per hour, and the lower the corresponding quantities in gallons per minute. At the left side is shown the loss of head in feet per 10 lineal feet of pipe, also in feet for each obstruction. As an example, suppose that 5000 lbs. of water per hour, equivalent approximately to 10 gallons per minute, are forced through 3000 ft. of 2-in. piping. Entering the base of the chart at the tenth abscissa from the left (5000 lbs.) follow the vertical line to its intersection with the diagonal marked 2 in. The vertical distance of this point from the base, measured on the left scale, indicates the friction load with this size pipe and quantity of water to be .034 ft. per 10 ft. of pipe, or 11.2 ft. for 3000 ft. of pipe. The intersection is also seen to lie between the .9 and 1 ft.-per-second hnes, that is, at a point representing a velocity through the pipe of .97 ft. per second. Extending a hne parallel to the other velocity Unes, this intersects the radia- tor resistance line at a distance from the base representing .078 ft., the head required to overcome the resistance of a radiator of the size that would be connected to a 2-in. pipe. Similarly, two-inch angle valves will each require .018 ft., and reducing tees with elbows .0065 each. In such cases as the latter, where the intersection comes below the chart, the lines can be re- started on the central horizontal line marked .1, and the reading on the scale divided by 10. The velocity head can also be ascertained from the chart by foUownig the velocity line to the non-parallel line marked v- 2g, but with the low velocity stated this is seen to be negligible, amounting to only .0145 ft. of head. The 5000 lbs. of water per hour given above represents, for a differ- ence of 35° F. between the hot water and the return water, 175,000 B. t. u. per hour furnished to the building. Comparison of the friction load with different size pipes will indicate whether it is a better investment to use smaller pipes, with less first cost for piping and less loss of heat by radiation, or to increase the size of the pipes and thus keep down the friction load and the steam consumption of the pump. The resistance of branched circuits may be found as follows: Jjct Ri, K^, K,., etc., be the individual resistance factors of the branches in parallel and let R be the resistance factor of the combined branches, then 199 COCHRANE HEATING ENCYCLOPEDIA THE TIME ELEMENT IN H EATING' APPARATUS The following extract from an article by Mr. James A. Donnelly may prove of value to those interested in heating guarantees or the rapidity of cooling of buildings: "A chart taken from a recording theimometer which was placed in a mill constructicn building February 23 to 25, during a very cold spell of weather, illustrates very nicely what often happens over Sunday in a factory building. This building contained a great deal of machinery, as well as metal in the course of manufacture, which would probably affect to a considerable extent both its heating and cooling curves. "The chart start.? at 68 (leg. at 6 p. m. on Saturday, when steam was shut off the building. The rule of operation of this plant was to allow the building to drop to 50 deg. before turning on steam. This point was reached at 6 a. m. on Sunday, when live steam was turned on, heating the building to about 59 deg. at 11:30 a. m. Steam was then shut off and the building cooled down to 48 deg. at 11.00 p. m. Sunday, when steam was again turned on. It was kept on until 6 a. m. Monday, when it was shut off preparatory to starting the engines. During the one-half hour that it was shut off it was seen that the temperature dropped about 2 deg. Exhaust steam was then put on and the temperature reached 66 deg. at 12 o'clock noon. During the noon hour, while the engines were shut down, no live steam was used and a drop of 4 deg. is recorded. Exhaust steam being turned on again, the building reached a temperature of 68 deg. at 6 p. m. Monday. "The time element in regard to the cooling curve of buildings presents one other feature of considerable interest. The collection of a number of cooling curves from the same class of buildings would, all other things being equal, indicate the difference in the rate of air leakage. It might then be possible to specify the kind of construction which might be expected in a new building to be one which, when heated to 70 deg., would not have more than a certain specific drop in temperature in a given number of hours, when the outside temperature is at a particular point. This would be an indication of the value of weather stripping, for example, in maintaining the temperature of a building when heat was shut off. "Perhaps the usual guarantee that apparatus shall be of sufficient capacity to maintain a temperature of 70 deg. in zero weather, in case of a building which is continuously occupied, might be modified to a guarantee that the apparatus shall be capable of raising the temperature of the build- ing from, say, 50 to 70 deg., in 3 hours, when the outside temperature is at zero, in the case of a building which is occupied intermittently. It is doubtful if suflScient data are available at the present time to figure intel- ligently for such a guarantee, but it is hoped that an extended study of the time element may render such data available." T £ if; ;Ii F' e R A T U RE G U A R A IM T E E S Ordinarily a contractor guarantees to heat a building to a certain tem- perature with the outside air at, say, zero. When the building is finished however the outside temperature is considerably higher and it is a 200 HEATING TABLES AND DATA question what temperature the rooms should have under these conchtions to fumu the guarantee. Prof. John R. AUen offers the foUowing table showmg the room temjierature for different outside temperatures corres- ponding to a guaranteed room temperature of 70° F. at zero outside, with the same radiation in the room and the same steam temperatm-e. ROOM TEMPERATURES WHICH MUST BE MAINTAINED TO MEET GUARANTEE OF 70° WITH ZERO WEATHER Temperature of Temperature of room Temperature of room Outside Air 2 column radiator 3 column radiator —30 52 53 —20 58 59 —10 G4 64 70 70 10 77.5 75 20 83 83 30 90 89 40 97 95 50 103.5 105.5 60 110 108 70 117 115 Mr. N. S. Thompson says: "When the plant is tested, if it meets the guarantee, the resulting temperature in the rooms will be ecuial to or greater than tj given by the following formula : , _T il— 1,)_- t,(T— t) -~ t— t, t =inside tempei'ature named in the guarantee. 1 1 ^outside temperature named in the guarantee. to^inside temperature maintained during test. 1 3 ^outside temperature during test. T =temperature of steam or water, assimietl to be the same in test as in guarantee. "The accuracy of the above formula depends on the following: The heat losses from the building are in direct proportion to the temperature difference inside and outside; the condensation from direct radiation is proportional to the difference in temperature of steam or water in tlic coil and that of the room ; and in cases of indirect or blast coils the condensation is proportional to the difference in temperature of steam or water in the coil and that of the entering air. "There has been considerable argument recentlj' as to the correctness of the above hypotheses, without advancing any that are more reasonable. "One reason for a plant in a newly constructed building failing to pro- duce the expected temperature may be that so large a part of the heat given off by the coils is taken up in drying out the brickwork, etc. This is especially noteworthy in concrete buildings. "In making the test the boilers should be run on the guaranteed pres- sure; and in case of fan work the dampers should be set to give the jirede- termined distribution of air and the fan should be run at the specified speed with all vent ducts open." 201 COCHRANE HEATING ENCYCLOPEDIA - CO ci lOCO I-, GO CO CO CO CO t^ CO C0C5O CD CD t~ o o -6 - iO T-H CO t^ LO^ C3 t-- CD 00 t^ § d ■ w CI ■ CD CO CI CO Xf^ lO CO CO CO CO CD t-- r- CC CO CO CO CO' oio o CO t^ t~ z < Q. ^ t^ CO .-H CI CI 03 CO CO CO Tfl LO CO CD CD CO CD r^ CO -* CI CD l>- GO Ci CO CO CD CO lO CO CI o o o ^ r- CO QC' CO CO c^ r- LO CO CI 00"^ ; o -^ ■ 00 a> CD o < . . 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CO o b S3 ?! ^ ft C , o o O^ Ol Oi 05 1-1 CO iO oo o c; ci c^ LO LO t- GOO CI O CI d LO CC -H -— 1 ^ ^ CI C4 CI CI CI ^ r^ o^ (M C^^ CI CI CO O) CI CI CI CTi CO -rti ^ t^ Oi CO 00 oo cq c< c^ s o C C C^ G C C C C C fi ^ jo_o_o JD^X!£ JlJ^ JD C' o; QO t^ CO lO -rt^ CO CI -^ I O i-H CI 00 ■ut -bs aaci sqi '3jnes9jd aSuBQ 202 HEATING TABLES AND DATA TEMPERATURES FOR TESTING DIRECT STEAM RADIATION PLANTS By W. W. Macou. Referring to the table on the opposite page, suppose that a direct steam radiating plant has been installed under a guarantee to warm the building to 70 degrees when it is zero outside, with the steam at 5 pounds pressure. Rather than waiting until it is zero the contractor makes a test when it is 22 degrees out of doors and circulates steam at 3 pounds pressure. The table is used to determine what the indoor temperature should be if the system can be counted on to meet the specifications. It will be noted that each vertical column gives figures for the pressure at which it is expected to operate during zero weather. The horizontal lines correspond to the pressure at the time of the test. It will be noted in the vertical column marked 5 pounds that opposite the 3 pounds pressure of the test a temperature of 68. 3 degrees is to be expected when it is zero outdoors. But the test is made at 22 degrees, not when it is zero. At the bottom of each vertical column is given a factor which is the number of degrees additional which must be realized in the indoor temperature for every degree that the outside temperature is above zero. As the temperature at the time of the test was 22 degrees above zero, we must add to 68.3, 22 times 0.692, or 15.2 degrees, making a total of 83.5 degrees, the temperature which should exist indoors to meet the guarantee. OFFICE PRACTICE IN ESTIMATING HEATING AND VENTILATION By John D. Sniiill. The following report, made to the American Society of Heating and Ventilating Engineers, represents the b.^st practice as ascertained from members of that society: Rule for Estimating Radiation. — The majority favor a formula based on the heat-unit loss through various cooling surfaces and materials and the number of heat units required to compensate for air change due to leakage and exposure. Coefficient tables for this purpose are found in a number of hand-books and the losses due to air change represent what the engineer's judgment dictates, except where fixed by law. Carpenter's and Mill's rules are largely used also. Air Changes Hourly. — This factor seems to be a very indefinite on where the amount of air displaced is not fixed by law or otherwise. In buildings where no mechanical ventilation is provided, the rate of air change would be affected by a number of causes, one of the principal causes being natural leakage, which varies with the kind of construction, the ex- posure, the wind velocity and the height of the building. The kind of window frames used has a great deal to do with the rate of infiltration of air. The sides of the building exposed to prevailing winds will, of course, show a marked increase in air displacement over the {)ro- tected sides. Air currents, however, between high buildings, due to de- 203 COCHRANE HEATING ENCYCLOPEDIA flection from one to the other, will often affect the surface which otherwise would be protected. Tests made by Mr. H. W. Whitten have demonstrated that with wind velocities below 6 miles per hour infiltration is reduced to a minimum; while with velocities as high as 30 miles per hour a very sub- stantial effect is produced upon the rate of air change from the interior of the exposed portion of the building. Again, the leakage is relatively greater as the building increases in height, due to increased wind pressure at increasing heights. From the foregoing observations it is important to use consider- able judgment in arriving at the maximum allowance to conijjensate for losses due to this element, and m the absence of a fixed rule, the following schedule, in the author's opinion, would be a safe l)asis foi- calculating the ainomrt of heat required under maximum conditions of air change in addi- tion to that required to offset lo.sses through the coolmg surfaces. Radia- tion on sides of buildings subjected to prevailing and cold winds should be increased 10 per cent, up to the tenth floor, and 1.") |)er cent, above. Allow air changes per hour for various rooms and classics of buildings as given in the table: (.)fhce Buildings. — Portions above grade, one air rliange per hour: ba.se- inent, general, four air changes ])er hour, and mechanical plant, ten air changes per hour. Factory buildings which have no mechanical or natural ventilation, one change per hovu'. For factories where large doors from the (jutside are frequently opened, about four air changes per hour. Residences, having loose windows, two clianges per hour. Churches, four changes per hour except small rooms, which should have five to six changes per hour. These data for churches contemplate mechan- ical ventilation. The majority of public buildings and many of the factories require ventilation by the fan system of heating. Hotels. — Following air changes are usual: engine room, changes every 6 min.; restaurant, 6min.; basement toilet, .5 min.; billiard, 10 min.; barber shop, S min.; dining room, 1.^ min, : ]ialm room, 12 min, ; ImlTet , S min, : cafe, ,S mill,; lobby, under balcony, .S mill, ; main lobby, 121) luiii,; banquet hall, 1.5 min.; retiring room, 10 min.; kitchens, 'S min.; all others, 1.5 min., and toilets, li min. Libraries. — Corridors, change every 15 min,; basement rooms, 15 min.; reading rooms, I'i min,; inside rooms, ,S min,; corner rooms, 7 min., and toilet rooms, 5 min. Lavmdries should have an air cliange eveiy 4 to (i min. The usual specifications of air supiilies ]M'v person are as follows: Hospilals, ordinary. o.5 to 40 lai. ft, iier min.; hospitals, e])idemic, SO cu, ft, |)er nun,; workshojis, 25 cu, ft, (icr min,; ])ris()us, iJO cu. ft, per min,: theaters, 20 to 30 cu. ft. per mm.; nieeling halls, 2(1 cu. ft , |)(a- min, ; schools, 30 cu, ft, per mm, |)er child and 40 cu, ft , ]ier min, jii'r adult , Fnchinj lidilinliiiiL. — Till' consensus of o))imoii is deciiledly against in- stalling radiation in factories only sufficient for noriual winter temperatvues and increasing steam pressure to compensate for deficiency when minimum winter temperatures prevail, especially where exhaust steam is used for heating, as the engines would be subject to back pressure and general 204 HEATING TABLES AND DATA efficiency reduced. The money saved on first cost of the heating system would be spent in operation later, thus resulting in poor economy in the long run. It would, therefore, appear that this method would not be con- sidered good practice, although owners are often influenced to cut down the first cost in this way, not fully realizing the net result. Using Mains for Hcaling.—The conditions and class of buildings govern largely whether the mains should be used as heating surface or should be covered. For low buildings and not excessively long runs, the mains are very often left uncovered, and without bad effects. In high buildings and in central heating systems, however, it is essential to cover mains in order to maintain as high a pressure as possible at the terminals. There have been cases where the steam chilled or condensed to such an extent due to surrounding temperature that it became necessary to cover the mains. The consensus of opinion is to cover the mains, as a rule, for best heat distribution. Radiation in Large Rooms. — The majority favor figuring the radiation on the same basis for all exposures and placing a larger proportion on the most exposed or windward sides, it being the idea that the heat will equalize, due to wind pressure, and eventually find its way to the opposite side of the building, whereas, if the same proportion were placed all around, the tem- perature on the windward side would be too low, and on the opposite side too high. To figure the radiation the same all around and then add to that on the most exposed or windward side would require more radiation than otherwise, and would not be so effective and economical as the first method. Pipe Coils in Fo.ctories. — Given a factorjr building, exposed on four sides, and two or more typical floors, it has been held that to install pipe coils around the walls to care for cooling surfaces is sufficient to maintain proper temperature without taking into consideration cubical contents. This seems to work successfully in some cases, and in others it is found that radiation is insufficient. There is a certain percentage of a room of large dimensions which may be neglected with regard to air changes, but just what proportion is yet to be satisfactorily answered. 205 COCHRANE HEATING ENCYCLOPEDIA INDEX Absorption refrigerating system, . 118, 120, 121 Air, properties of 154-l.->5 heatunits to heal |j;iven volume . . ir)0 amount required per occupant . . 152, 203 amount supplied with gi\-en heat loss l'''^'^ capacity of flues l'''^ removal from hcatinc system , 51. 170 Allen, John R 152, 15S, Itil, \m, 201 American Society Heating and \on- tiiating Engineers 203 Apparatus replaced liy C'nchrane heater .S-19, i-s, '.)5, 102. 103 Armak heating s\bti'iii 50, 55 Back pressure, effect of varying . 1S0-1S2, 200,202 Back pressure vah'c 48-103, 110-114, 13G-142, 1X2 Baldwin, "\Vm. J 15S Bends, pressure drop in 171 Bishop-Babcock-BeckerCo S3-S5 Bleeder turbines 144 Bleeding interm<'diale refei^cr fur heating 111,184, ls7 Body heat 157 Bolton, R, P 148 Brooniell heating system 52, 57 Building materials, heat loss through 145, 146 Builduigs.-lassitirdl.y use 145 By-passing, difliculty of with old system 1 1-14, IS . Capacity, heater 31 Carpenter, R.C., 153, 154, 155, 15(1, IGO, 170 Carpenter, Sidney C 171 Check valve for bleeder turbines , . . 144 Clay manufacturing 1^12 Close cjuarters, heaters for. .. ,30-39, 101 Closed heaters, metering water fmm 124 Closed heaters, shortcomings ul,, . .s, 33, G8 Comparisons: Steam-Stack vs. old arrangement 8-10, 95, 102, 103 Closed vs. open heaters S, 33-37. 08 Live vs. exhaust steam heating . . 185-191 Hot vs. cold softening 129, 130 Compound engines, taking steam from receiver 1 1 1 , 1 84 , 187 Compression refrigerating system . . 116, 119 Condensate 51, 109 Condensing plants 107-115, 144, 179, 1S4, 186, 194 Construction of heaters 29-35 Cooling, rate of in lnuldings 200 Covering pipe 161, 2ti5 Crescent heating system 54, 59 Cryer heating system 56, 59 Cyhndrical heaters 30-39, 120 Day-Light Chart 1S4 Dexter heating system 5s, 61 Donnelly, James A 172-176, i^fX) Doors, heat loss through 147 , Double units 41-44 I Dreyfus. E, D 181 Drip pipes 170 Dry kilns 97,101 Dunham lieating system 60, 61 Eddy heating system 62, 63 Elbows, pre.'^.sure drop from 171 Elevator, power to operate 179 Estimating proportions of heating system 157. 172, 179, 203 Exhaust, amount available 107-115, 179, 185-190 Expansion joints 176, 197 Extension softening system 130 Exterior views, 4, 30, 36-38, 42, 101, 120, 126 Faults of common .systems, 8-17, 95, 102, 103 Flow valves 112-115, 142 Flue capacity 156 Fool-proof feature 13, 15, 25 Forced ventilation 151 Free exhaust heaters 41 Friction loss, 164-1 6s, 171, 172, 174. 190, 199 GifTord, Byron T ]k1 Globe \'alves, pressure drop m 171 Gro3\ enur, W. M 160 Gunby. F. M 184 Haines heating system 64, 65 Harvard Medical School 151 Headroom, saving 36-39, 101 Heat balance with \arious sj-stems 107-111, 185-190 Heat supplied by occupants and l)\' lights l.->7 Heat loss through walls 145-147 by leakage 148. 158, 203 by ventilation 150-153, 203 from pipes 160 Heating seasons 147, 18i;^i,s4 Heating system, necessary parts of 9, 47 Heating systems illustrated 47-103 Heating and Ventilating Magazine, 145 Hoffman, James D 145, 157 Horizontal cylindrical heaters 36-39 Hot blast heating systems 97, 100, 101, 120, 185 Hot process softening system 128-130 Hot water heating 104-108, 193-199 Hotels, reasons for heating with ex- haust steam 190 Hul)l)ard, C. L 171, 179. 197 HuUe.. iry2, 1.^,3 Humidity, proper degree of 153 Ice and refrigeration plants. . . 104, 116-122 Illinois Engineering Co Gii, 67 Indu.-^l [ ies. use of exhaust in \-ari(.iu3 5, 191 Injiei-sMll-S.Tueant Drill Co 171 ItisI;(II:iIiotis, photographs of. 6, 11, 13, 15. 25, 34, 46, 63, G5, 67, 71, 73, 77, 128, 1L19 Interior ^-iew of heater 2S, 125 Intermittent heating 156, 200 Isolated plant vs. purchased po-\A-er 185, 190 Kieley heating system 67-69 Kilns, dry 97, lOl Kinealy heating sj-stem 70, 71 Kriebel heating sj'steni 72, 73 Leakage, heat loss by 148, 1.58 Lecuir, M 185 Lever i-onlrol 23 Lights, heat sui.plie,! hy 157 206 INDEX I / Li\ e \ s, exhaust steam heating , . . 1S5, 190 Longmans. Green & Co 162 Lumber drying 97, 101, 191 Maton, W. W 202, 203 :Mim C. T 184 Miins, see pipes Make up %vater regulator 53 M^lt drying 191 Mirks & Davis 162 Materials of Cochrane Heaters. ... 31 Measuring feed water 123 Meitr Konrad 19S, 199 Meters, Cochrane Independent and Metering Heaters 44, 122-127 Miller, Warren H 185 ^Moisture to be supplied 153 Mnliue heating system 74; 75 Momsh heating system 75, 76 Morehead heating system 78, 79 Morgin-Clark system 79, 80 Monn 152 Moses, P. R 190 Muffle tank and oil separator, 18, 117, 132 Multiple unit 41-44 Multiport vaU-es 136-144 900 Series heaters 38, 40, 41 Ocagne. M. d' 168 Occasional heating 156, 200 Office buildings 63 Old style methods of connecting heating systems 8-19, 102 Packing houses 71, 192 Piper manufacturing 192 Paul heating system 81, 82 Pipes capacities of yarious sizes ... - 172 lengths for given radiating surface 160 surface per ft. length 160 expansion joints 176-178 effects of covering 161, 205 equivalent to globe valves, bends and elbows 171 Pipes steam 160, 164-169, 172-176 pitch of 178 use of for radiation 205 Pipes hot water 193, 196-199 loss of head by friction at various loads 196, 198, 199 Pipes return 169 Pipes drip 170 Pitch of pipes 178 Plenum system of ventilating 151 Positive Differential system . .81, 84, 172 Prausnitz 152 Pressure drop 164-168, 171-174 Pumps, circulating and vacuum, ca- pacity of 171, 197 steam consumption 179 Raber, Benj. F 145 Radiator surface, calculation of . . . - 157-159, 173-176, 179, 193, 203-205 RailT\ ays 34 Receiver, bleeding for heating pur- poses 111.184, 187 Receiver separators 135 Rerknagel 195 Reducing valve 55 Refrigerating plants 104, 116-122 ' Reliable" heating system 83, 85 Return mains, size of 169, 173-176 Return tank 53 Revue de Mecanique 186 Rietschel 152, 156.159,193 Ritt, E 164 Rochester heating system 86, 87 Safety Exhaust Outlet Valve 48-103, 110-114, 136-142, 182 SaMngs in installation cost 17, 95 &a\ings from use of exhaust 7, 107-115, 185-190 Scale 128 School buildings 40 Separator attached to heater 19, 29 Separators, Independent Steam and .Oil 11. 15, 131-135 Simonds hea-ting system 87, 88 600 Series heaters 41,42 Small, .John D 203 Small heaters 30, 38 Snow, W. G 169, 170 Softening feed water 128-130 Sparks heating system 87, 90 Speria. heaters 37-45, 101, 122-130 Specifications 4.5 Steam consumption with various layouts,. .107-117, 179, 180, 185-190, 194 Steam, properties of 162-164 Substitutes for Steam-Stack Heater, 8-19, 95 Sugar manufacturing 192 Sure Seal heating system 89. 92 Taggart, R. C 178 Tanning plants 192 Temperatures at which to keep rooms 145 pressures necessary to secure 181, 205 to be carried in hot water system 195 Temperature guarantees, how to test 200-203 Temperature equivalents of wind velocities 149 Temperatures, outside, pressure dif- ference to compensate for. , . , 181 mean maximum, mean minimum, and minimum during 3 winter months, for 21 cities 147 length ot heating season in 9 cities 183 temperature and day-light chart for Philadelphia 184 hourly variation at Pittsburgh, by months 182 effect of variation over Sunday . . 200 total hours at various temperatures throughout season, at Scranton 182 Textile plants 15, 25, 192 Theaters g Thermograde heating system 89, 03 Thompson, N.S 169, 196,201 Time element 200 Trane healing system 01,94 Transmissions, see Heat losses and Radiation Trap furnished with heater 29. 32 Turbines. . .110-117, 142, 144, 187, 188, 194 Tweedy, E. F 149, 183 University of Michigan 161 Users, prominent 5 Vacuum Oil Separators 133, 134 Vacuum pumps, size of forgiven radi- ation 171 Valves, air 170 Valves. Cut-Out, operation of 10, 20-27 Steam-Stack Heaters without, 38,40,41 on free exhaust heaters 41 , 42 Valves, flow 112-117, 142 Valves, Multiport 48-103, 110-114, 136-144, 182 Valves, reducing 55 \ an Auken heat'ng system 01, 96 \"elocities, steam 168, 169, 174 ^'elocities, wind 149, 151 Ventilation 151-153, 203 Water, weight and volume of at various temperatures 195 Water-sealed heater 41, 42 Webster heating system. . . .91, 95, 98, 09 Whitten, W. H 151 Wind velocities, effect of 149, 151 Woodworking plants 97, 101, 191 207