US2661933A

US2661933A - Evaporative cooler for condensing hot compressed gas

Info

Publication number: US2661933A
Application number: US273216A
Authority: US
Inventors: Charles N Deverall
Original assignee: Niagara Blower Co
Current assignee: Niagara Blower Co
Priority date: 1952-02-25
Filing date: 1952-02-25
Publication date: 1953-12-08
Anticipated expiration: 1970-12-08

Description

8, 1953 c. N. DEVERAL-L EVAPORATIVE COOLER FOR CONDENSING HOT COMPRESSED GAS Filed Feb. 25, 1952 I 4 Sheets-Sheet 1 NVENTOR.

6 u 11 a: a w

w w 7 w a w 0 a 1 F k m I Dec, 8, 1953 C. N. DEVE RALL EVAPORATIVE COOLER FOR CONDENSING HOT COMPRESSED GAS Filed Feb. 25, 1952 4 Sheets-Sheet 2 Dec. 8, 1953 c. N. DEVERALL 2,661,933

EVAPORATIVE COOLER FOR coNDENsING HOT COMPRESSED GAS v 4 Sheets-Sheet 3 Filed Feb. 25, 1952 Dec. 8, 1953' c. N. DEVERALL EVAPORATIVE COOLER FOR CONDENSING HOT COMPRESSED GAS Filed Feb. 25, 1952 4 Sheets-Sheet 4 I ;2 7/72 a wzzvaw 2 5 #7. w M w 2 w w 1 J, 1 5| -L w m W H wm ATTJAA [YS Patented Dec. 8 1953 UNITED STATES PATENT OFFICE EVAPORATIVE COOLER FOR CONDENSING HOT COMPRESSED GAS- corporation. of New York Application. February 25, 1952; Serial No..273,216'

10. Claims.

This invention relatesto. an evaporative; cooling tower and is shown as embodied. in a con.- denserforcondensing the hot compressed gas-f a. refrigeration system, although it can be em ployed wherever it is desired tocool a gas or'liquid toa point near the. wet bulb temperature of theatmosphere. The cooler is more particularly in.- tended for use where there is a very heavy load, such. as. to cool andcondense the-hot compressed. gas of, say, a 350 ton refrigeration system.

One of the. principal objects ofv the. invention is. to provide a cooler for cooling and/or con-- densing a. gas or a liquid, such as compressed superheated refrigerant gas, in which the cool ing. water is recirculated andv the; cooling effect achievedv principally by evaporation. of cooling water. on thetubesthrough which the gas is conducted. By this. means aneconomy is effected in the-cost of. cooling water and by its use the municipal. sewer systems are not. overtaxed by the installation of large refrigeration systems. for which the present cooler or condenseris particu larly designed. and which normally require large amounts of: cooling. water for condensing; the hot compressed refrigerant.

Another object. of the invention is to provide such anevaporative condenser or cooler which is. specifically intended for. very heavy loads, suchascondensing the compressed refrigerant gas for refrigerating systems producing hundreds-of tons of. refrigeration.

Another object of. the. invention is to.- provide. such. a large capacity.- cooler. or. condenser which iscomposed principally of relatively small sized identical. units. which. can be. readily produced in a shop. and which, also. canv be readily assembled. at. the. location.

Another object. of. the invention is to provide such. a. large. capacity cooler or condenser which is extremely flexible incapacity, it being possible to cut. any desired number of the units; into and out. of operation thereby to. adjust thev cooler or condenser to the. load being handled;

Another object of. the invention. is. t provide such. a cooler or. condenser which can be readily repaired. withoutstopping operation, it being. pos sible to cut the defective unit outof operation and repair that unit without. interfering. with. the operation of the otherv units.

Another object. of. theinvention. is to. arrange the flowsv of the air. and water so. as to obtain maximum evaporative cooling efficiency, thereby to require a minimum amount of heat exchange hibesurfaceand'space.

Another object of the. invention is to provide.

2 such a cooler or condenser which can. be readily keptlin a clean and efiiciently operating condition, the spraysand sprayed surfaces being readily accessible from a large central chamber which. a manwith a ladder can. enter.

Another object of the invention is to provide a structure which is compact, considering the.-

vcry high capacity of the apparatus. 1

Another object is to provide such a cooler which is suitable for use in cooling fluids having a relatively high entering. temperature; Temperatures above F. spray water will evaporate rapidly and deposit a scale upon the'tubes conducting such initial high temperature medium to be cooled. In accordance with the present inventionthe temperature of the medium tobe cooled is. first reducedto at or below 115 F. by air cooling. before being. subjected to evaporative cooling so. that any. deposit upon theisprayed tubes which. doesoccur is sosoft asto be immediately washed off. the. pipesby thesprays.

Another object of the present invention is to provide such a. condenser in. which the first or air. cooling stage merely removes sensible heatv from the gas. to be condensed to bring it below the point at which a scale would form with evaporativecooling and. to. remove the balance of the sensible heat and the latent heat in a second stageby evaporating. cooling. By this means the preponderance-of. the heat is. efiiciently removed by evaporative cooling and a relatively small heat exchange, tube surf-ace is. required for the first or air cooling stage. I

Another objectof. the invention is; to provide, in. combination with. a. condenser, means for. re. moving the. maximum. amount of oilfrom theses being condensed. thereby toprevent such. oil from. building up and caking v on the heat transfer surfaces in. contact with which the condensed gas is subsequently passed.

Afurtherobject is-to-provide such an oil eliminator in which. the. oil is conveniently availablefor reuse.

Another object is toprovide such any oil eliminator which does; not have any moving parts:

ther than the: valves-necessary to remove the oil type of condenser in which the cooling effect'is' obtained. principally from the evaporation of wateron thecooling.surfacewhichtis arranged in.

an. air stream. passing over the: surface. Such: an lloratwe: conden r has: manytimes: the

:- cooling. capacitpofi adry coil'of the same size'and uni er normal conditions cools the fluid being condensed to a much lower temperature than is possible with a dry coil.

Another obiect is to provide such an oil eliminator in cornsination with a condenser which is, without special control, self-balancing under varying load and wet bulb conditions such selfbalancing operating to remove the maximum amount of oil from the fluid being condensed under all operating conditions.

Another aim is to provide such an oil eliminator, in combination with a condenser, in which the maximum removal of oil from the gas being condensed under all load and atmospheric conditions can be placed under accurat instrument control.

Another object is to provide such a large capacity condenser which is relatively low in cost, considering its extremely high capacity, both in fabricating the units and also in setting up these units on the job.

Other objects and advantages of the invention will be apparent from the following description and drawings which:

Fig. 1 is a front elevational view of a large capacity, tower-type evaporative condenser endbodying the present invention.

Fig. 2 is a side elevational view thereof, with parts broken away, and viewed from the right hand side of Fig. 1.

Fig. 3 is a vertical transverse section taken generally on line 3-3, Fig. 2.

Fig. 1 is a top plan view with a part of the air outlet screen broken away.

The tower-type of condenser embodying the present invention is substantially symmetrical along a vertical fore-and-aft medial plane and hence a description of the apparatus at one side of the condenser will be deemed to apply to the counterpart apparatus at the opposite side of the condenser, and the same reference numerals have been applied.

The invention is shown as embodied in a large tower-type condenser designed for cooling and condensing the hot compressed gas of compressorcondenser-expander refrigeration apparatus of large capacity, say, 350 tons, as well as removing oil from this gas.

The condenser includes a main sheet metal shell 5 of generally rectangular form having a front wall it,

side walls

8, 8 and a rear wall s. The main shell is also provided with a top wall it connecting the front, rear and side walls. The bottom wall it of the shell comprises side drain boards or sheets each composed of an outer sheet 52 each connected with the adjacent side wall 8 and running the full length of the casing to connect the front and rear walls 6 and 9 and inclining downwardly toward the center of the shell, and a sheet is of lesser inclination connecting at its upper edge to the lower edge of the sheet l2 and extending the full length of the shell. These drain boards or sheets l2, l3 discharge into a sump indicated generally at M having vertical walls Iii extending the full length of the shell and a trough shaped bottom It. The end walls of this sump are provided by the front and rear walls and 9 of the main shell and the sump contains a body is of water. This sump also has a depressed part it.

A pair of circular exhaust stacks 20 rise from the top ill of the main shell, these stacks being in fore-and-aft alinement at t e center of the shell, as best shown in Fig. 4. Each of these circular stacks is provided with an annular flange 2! at ill its upper end and to which a circular screen 22 can be secured. Within each of the stacks 2c is mounted a disk or propeller type fan 23 mounted on the shaft of an electric motor 2 although reduction gearing could, of course, be employed. The axis of each propeller and its motor is concentric with the axis of the corresponding stack 28 and the motor casing can be supported in any suitable manner as by radial arms 25 connected at their inner ends to the main shell of the motor 24 and at their outer ends to the wall of the cor responding stack Ell. The propeller type of fans 23 are shown as each having four blades, although any number could be used, and are rotated in a direction to draw air from the interior of the main shell up through the circular exhaust ducts 2G and out past the screens 22. These blades can be fixed or can be variable pitch blades.

Approximately midway of the height of the main shell 5 a bame plate 23 is provided at each side thereof, this baffle plate extending the full length of the shell and connecting with the front and rear walls 6 and 9 thereof. Each of these baflle plates 28 comprises an upper inclined portion 29 the upper longitudinal edge of which connects with the side wall 3 about midway of the height of this side wall. The lower edge of this inclined portion 29 is continued downwardly at a steeper angle to provide a downward extension 533 and from the lower edge of this downward extension 33 the bafile plate is continued horizontally toward the center of the condenser, as indicated at 3!. The inner edge of this horizontal part 34 of the bafile plate connects with the upper edge of a vertical wall 32 which extends downwardly from the horizontal part 3! and at its ends connccts with the end walls 5, 9 of the main shell, this vertical wall 32 thereby forming a part of the baflle plate 25. The lower edge of each vertical wall 32 is bent to extend horizontally toward the companion side wall 8, thereby to provide a shelf or flange 33 extending the full length of the casing. In horizontal alinement with this shelf or flange 33 a similar shelf or flange 34 is mounte on the side wall 8 of the casing.

The bafile 28, including the vertical wall 32 and side and end walls of the main shell provide a spray chamber, indicated generally at 35, this spray chamber being open at its bottom, as indicated at 36 and this opening at the bottom of the spray chamber being spaced from the bottom Wall ll of the shell so as to provide a horizontal passage 38 leading to a central plenum chamber 39 the lower part of which is defined by the

vertical walls

32, 32 of the two spray chambers 35.

Each of these spray chambers 35 is provided with a pair of air inlets indicated generally at so. These air inlets are arranged in the side Walls 8 of the main shell and are arranged to admit air into the upper parts of these spray chambers. Each of these air inlets is in the form of a rectangular neck 4! projecting outwardly from a rectangular opening in the corresponding side wall 8 and provided with an outwardly extending vertical flange 42. This flange 42 of each of the air inlets preferably supports a screen 43 in any suitable manner.

A rectangular roof casing indicated generally at is mounted on the top wall ill of the main shell 5 on each side of the circular air exhaust ducts 29, these casings id extending fore-and-aft but not extending the full length of the main shell 5, as best shown in Figs. 2 and 4. Each of these roof casings is shown as having front and rear walls 46, so, fore-and-aft side walls 49,

. eemed to. the. top. wa .lli of tile 1 memos;

D and a top wall 5 t thebottom being open and ll? 3.11 if casi g,

outerside. wall .9 of ea s s. provideslin its bottomv with. a.- ec. an.e ju r an."

nlet. 52.. anti. wbi ii permits. atmo p ric.

air toeoter the root" os ne. Thisre a or air inlet nreie ablv tends the reater part o the. .f.ore.a1.1.cl-aftl h the roof Ba ins. 4 as best. llustrated in.

Wall, 8. of. the. ma n snell oh. reot nsul opening is. covered. anejenclos d. by its r o oasins. 4,5 and is boundedhv the fron anoreair walls 4.6. and. 4.8,. sid Wall. 58- and. vertical; cen al. p ition. 5.4 of its casing 4.5.. The lower edge. of each vertical partition 54 projects into. the main shell 5. and connects with a baflle plate 58 which inclines downwardly toward the center of the main shell 5, to provide a passage Elleading to the plenum chamber .59, This baille p a onnect at, its ends with the front and rear walls ii, 9 of the. main shell. The lower edge of this baffle plate. 58 connects witha vertical, Wall. 62, the onus of this vertical wall also connecting with the end walls 6. 9..0f.the. main shell... It Willv be seen that eachverticalwall 62 forms. a continu tion of t e h me plate 58.. The. low r ed e. of eacb'v ical. wall E2 is form-ed. toexterld toward the adjacent side wall 3 of the. main shell 5 a provide a shelf or flan i h ri ntal. alinement witnth s shelf or flange. as. A counterpart. shelf. or fl n G5. is provided along, each. of the side wall 8. of e. shell.-

The baflle plate, 5.8... vertical wall e2. side. front. rear and op. Walls of th main shell 5 provide. a pai of spray ohambsrs. indicated generally at as. each. s ray chamber bein open its ot tom,. as indicated at 65, this opening in the bottom of the spray chamber being spaoeg from the. baffle plate 28 so as tov provide. a horizontal passage 68 leading to. the central plenum chamber. 39, the upper part, of which defined by the

vertical walls

62, 52 of the two spray chamhers as. I

Each of these

spray chambers

5,5 provided with a pair .of airinlets indicated generally at.

:10. These. air inlets are arranged in the side walls. 8 of the. main shell and are arranged to. admit air to. the upper part. of the spray chembers 65.. Each of these air inlets. is in the form oi a rectangular neck ii projecting outwardly from an, opening the corresponding. side,- wall and provided with outwardly extending VQIf-s tical flange l2. flange, 12 of eaclgi of the air inlets lil preferably supports. a screen 13 in. any uitable. manner.- I

Fo1-acoess to. the plenum chamber 13.9., all afiflfiss. door 15 is provided in the. front wall 6.01". the. main shell. Through thisdoora man can, enterthe plenum. chamber .39 and by the use of a ladder access to the fan motor 24, From this can tral plenum chamber access also had to they internal spray p pi her inafter descr ed. Access, to. the several sprayohambers. .35 and 6,5 had through the several screened inlet opens inas. 4 .5, lit by nemoval of the screens A3, .13 I'Q':

spectively.

' From the above. the course of: atmopherie. air.

tbs-or anza esterses erea. .aae stoost; to oi -.movemeo be st a by the free t: sob sii eofthe in s. nt so thews screene ir into the cor spend ng: spray c mbe 11 rsl v throosn his spray o the tone pa s of. he. o respondoamnerfiti and lo downward y hrough ore y chamb rinto t h izonta E8: and. hen e nto. t e entral pa of 4.5, From the. top. of; the casing 45 this air flows downwardly throufii the: downflow pass is provided by the central vertical partition 5 i and ut throug the. p nin 5 in the top l or the mainshel-l into the horizontal passage 51' nd then e into t e upper part of the plenum chambes 39-. Air is exhausted from the upper leas of the p enum ch mber 39 y the f ns 23 n-toedi oharee uets Arranged in each of the lower spray chambers'35 is a pair of cooling or condensing coils 8 13. 86 these. cooling or condensing coils prefers e-seoaraie i. ve ical p tion i tend'n-g ;,he..f.1ilj1 length of the shell and these coils bein sup o ted by the shelves or flanges 33 and 54. Eaeh or these coils has an upper horizontal inlet header is; disposed adjacent the front. wall 6 of the main shell and a lower horizonta header 83 also disposed atl'jaeent the front wall 6. of

the mam she l. m et'li aaer 82 is. c nthe e r entin tub o the s ra sham- 8-2. has an i iron wa l 6 b main s ell and. conn ted byvalve 8t and; ertioa p pe 88 w t a hor zon a header 33, ari a cl exteriorly of the main shell. One. end o heade 8.9 is closed and its onposit e d onne ts it th sh l of an oil separator 50 the headers .89 form ng the out-. lets for this oil separator. This. oil separator is. conventional and has. the usual internal strucs tune to reduc the elocity and c a t imotions oftl e gas passing therethrou gli, the liqoiol partioles. of oil settlin to the bottom of the. separator from whiola the. oil can be removed through a valved. outlet. 91.

Boot: o the. soil outlet headers 8 3 a an out et no se: ex ending. through the ro t w n e a of the main shell and connecting with a manifold iiolol: 9.3... oon ioots the out et neck oils .89 t eac ide o tee aopara h eleoutle .94 from .3.- This, 9:2. of the t upper or zontal n et hea e -102 dispose s latent the imnt wall. of the main she and a lower horizon a header 10.3 also disposed adoee ecl. to ls e znoanioo outle he de b a p u jacent the front wall 6 of the main shell. Each inlet header I532 is connected to its companion outlet header by a plurality of serpentine tubes I04, these serpentine tubes extending the full length of the spray chamber 65, as illustrated in Fig. 2. The inlet header I02 has an inletneck I35 extending through the front wall 6 of the main shell and connected by a valve I I16 and vertical pipe I98 with a corresponding horizontal header 39, this header forming one of the outlets of the oil separator 9b as previously described.

Each of the coil outlet headers I03 has an outlet neck I I2 extending through the front wall 6 of the main shell and connecting with a manifold I I3. This manifold I I3 connects the outlet necks N2 of the two coils Hill at each side of the apparatus and is provided with a single outlet II4 from which the condensate can be returned to the refrigeration apparatus.

In each of the roof casings 45 on the roof or top wall of the main shell 5 is arranged a precooling coil indicated generally at I I5. Each of these precooling coils comprises an upper horizontal inlet header III; and a lower horizontal outlet header I I8, each of these headers being arranged adjacent the front wall at of the casing 45. These headers its and H3 are connected by a plurality of serpentine tubes H9 which extend substantially the full length of the casings 35, as best illustrated in Fig. 2. Each inlet header H6 is provided With an inlet pipe IZII and forms one of the inlets for the hot compressed refrigerant gas to be condensed. Ihe outlet header has an outlet pipe I2I which extends through the front wall iii of its casing 3-5 and connects with and forms the inlet of the oil separator III? as best shown in Figs. 1 and 2.

The water for the spray system is withdrawn from the downward extension I3 of the sump I4 by the inlet line I2 1 of a recirculating pump I25. The outlet line I25 from this pump connects with the central vertical pipe I38 01 a spray tree I29 arranged within the main shell 5. This central vertical pipe I23 has four branches I3b each extending transversely of the main shell and through the corresponding

vertical wall

32 or 62 into the upper part of the corresponding

spray chamber

35 or 65, these branches I33 being disposed above the coils 85 or IM within these spray chambers. Each branch I39 terminates in a valve I3! having a stem I32 which extends the side wall I! of the main shell and is provided, exteriorly of the main shell, with an operating wheel I 33. The outlet I34 from each valve I3! extends upwardly and connects with a pipe I35 extending substantially the full length of the corresponding spray chamber 35 or IE5. Each horizontal pipe I35 has a plurality of lateral branches I35 each carrying a downwardly directed spray nozzle I33.

It will be seen that water is withdrawn from the sump I I by the pump I25 and passes through the lines I25, vertical pipe I28, branches I30 and valves I3! to the longitudinal pipes I35 from which it is distributed through the branches I35, to the several spray nozzles I38. This water sprays downwardly upon the coils 33 and Ill!) in the

spray chambers

35 and 35, respectively, and wets these coils. It will be noted that both the air and water for these coils is supplied from the top of each spray chamber. The excess water from the spray chambers65 runs down the baflies 29 and vertical walls 32 to the sump I4. Excess water from the coils. 86 runs down the drain boards or plates I2 and I3 to the sump I4.

8. Operation In the operation of the condenser and oil separator as above described, the hot compressed gases, having a temperature of, say 210 F., from the refrigeration system is supplied through the two inlet pipes I20, and, as best shown in Fig. 3, enter the inlet headers IIB of the dry precooling coils H5 and pass through the serpentine tubes I III of these coils to the outlet headers I I8 thereof. In these coils the gases have their sensible heat reduced to a temperature of, say, 100 F., and at this reduced temperature the gases pass through the outlet pipes I2I to the oil separators 96. In these oil separators, the gas is subjected to the usual reduction in velocity and change in direction to cause liquid particles of the oil to settle to the bottom of the oil separator.

From the outlet headers 89 of these oil separators a part of the gases passes downwardly through the pipes 88, under control of the valves 83 to the inlet necks 85 of the inlet headers 32 of the group of condenser coils 80. As best shown in Figs. 2 and 3 the gases pass through the serpentine tubes 84 of these groups of coils and in this passage are cooled below the condensation point so as to enter the outlet headers 83 of these coils as a condensate. This condensate passes through the outlet necks 92 of these outlet headers 82 into the manifolds 93 from which the condensate is returned to the refrigeration system through the outlets 94.

The other part of the gases passing through the oil separators 9|! and the outlet headers 83 of these separators passes downwardly through the pipes H38, under control of the valves I06, to the inlet necks I05 of the inlet headers IIl2 of the group of condenser coils IflIl. As best shown in Figs. 2 and 3 the gases pass through the serpentine tubes I64 of these groups of coils and in this passage are cooled below the condensation point so as to enter the outlet headers I83 of these coils as a condensate. This condensate passes through the outlet necks I I2 of these outlet headers into the manifolds II3 from which the condensate is returned to the refrigeration system through the outlets II4.

A supply of spray water is maintained in the sump It and this spray water is continuously being withdrawn by the pump I25 which discharges, as best shown in Fig. 3, through the outlet pipe I 26 and vertical riser I 28 of the spray tree I23. From this vertical riser the water is distributed through the branches I36 to the horizontal pipes I35, the flow of water through each of these branches I 3!! being under control of the valves I3! which are manipulated from the exterior of the apparatus by the hand wheels I33. From the longitudinal pipes I35 the spray water is distributed through the several branches I36 to the spray nozzles I33 which discharge the water downwardly against the coils 8d and I33.

' A part of this water evaporates on these coils so as to reduce the temperature of the gas and condensate flowing through these coils to a temperature close to the wet bulb temperature of the outside air. lhe excess spray water from the coils IIIII flows down the inclined baiile 29 and vertical wall 32 and returns to the sump I4. The excess water sprayed upon the coils 8U flows down the inclined drain boards or plates I2 and I 3 and also returns to the sump I4. Accordingly it will be seen that the water is recirculated by the pump I25 and that the nozzles I33 discharge and distribute the stream of recirculated water over each of the cooling coils Bil and IIII) to wet the ll minimum. By so reducing the thickness of the films of water on the tubes to a minimum heat transfer from the outer surface of the film, which is subject to evaporation, to the tube surface, is improved and holding the water thickness to a minimum also prevents such build up of the water as would impede the air. Further by such downward flow of air, the air meets the evaporative coil surface at a minimum wet bulb temperature, thereby utilizing the highest possible moisture absorbing properties of the air. If the air moved upwardly, the air would first be contacted by the water falling from the coils which would increase the wet bulb temperature of the air before the air reached the evaporative coil surface.

From the foregoing it will be seen that the presentinvention provides a large capacity evaporative condenser or cooler which is composed of units which can be readily fabricated at a factory and also readily assembled in the field; which is fully accessible for repair, inspection or cleaning; which can be used in any number of sections to adjust it to less than capacity demands and to permit of repair of certain sections without shutting down the apparatus completely; which is free from scaling and also in which the oil is advantageously separated from the gas when the apparatus is used as a condenser; and which operates efficiently and without service difficulties.

I claim:

1. A cooler of the character described, comprising a shell having top, bottom, front, rear and side walls, an internal baiile at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other, a generally vertical wall enclosing the inner upper part of each of said spray chambers and having a space thereunder providing an air outlet from the lower inner part of each spray chamber to a central plenum chamber bounded by said generally vertical walls, a plurality of air inlets in each of said side walls and each leading to the upper part of a corresponding spray chamber, a pair of cooling coils in each of said spray chambers between its air inlet and its air outlet and through which the fluid to be cooled is adapted to pass and over which the air from the corresponding air inlet flows downwardly and out through the corresponding air outlet, the cooling coils of each pair being arranged side by side to extend generally parallel with the adjacent side wall of said shell, a vertical partition between each pair of said coils and extending parallel with the adjacent side wall of said shell, means arranged in the upper part of each spray chamber above the cooling coils therein to discharge and distribute a stream of water over the cooling coilstherein to wet the exterior of said cooling coils and to evaporate and absorb heat therefrom, a sump in the bottom wall of said shell, a pump recirculating water from said sump to said dis-'- charging and distributing means, an exhaust duct in said shell leading from said plenum chamber,

and an exhaust fan in said exhaust duct. I

2. A cooler of the character described, comprising a shell having top, bottom, front, rear and side walls, an internal baflle at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other and said bafiies forming with one another a central plenum chamberbounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said sidewalls and each leading to a corresponding spray chamber, the side of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and through which the fluid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of Water over eachof said cooling coils to wet the exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a precooling coil, means arranged to pass a stream of air over said precooling coil, and means conducting the fluid to be cooled in series first through said precooling coil and then through said wetted coils.

3. A cooler of the character described, comprising a shell having top, bottom, front, rear and side walls, an internal baflle at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other and said baffles forming with one another a central plenum chamber bounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said side Walls and each leading to a corresponding spray chamber, the side of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and through which the fluid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of Water over each of said cooling coils to wet the exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a precooling coil, means arranged to pass a stream of air induced by said exhaust fan over said precooling coil, and means conducting the fluid to be cooled in series first through said precooling coil and then through said wetted coils.

4. A cooler of the character described, comprising a shell having top, bottom, front, rear and side walls, an internal baffle at each side oftheside of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and. through which the fluid to be cooled isadapted to be passed, means arranged to discharge and distributea stream of water over each of said cooling coils to wet the exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, aprecooling coilat each side of said casing, means arranged to pass a 'stream'of air'over' each 13 of said precooling coils, and means conducting the fluid to be cooled in two streams each stream of said fluid passing in series first through one of said precooling coils and then through the wetted coils on the corresponding side of said shell.

5. A cooler of the character described, comprising a shell having top, bottom, front, rear and side walls, internal baffles at each side of Said shell and extending horizontally :lengthwise of said shell and connected'to said .shell to provide with said side walls a pair, of spray chambers arranged one above the other, each of said baflles being formed to extend downwardly toward the center of the shell and to provide anlair :outlet opening from the lower part of each :spraychame ber to a plenum chamber bounded by said bafiies and said top, bottom, front andirear walls, a plurality of air inlets in each :of said side walls and each leading to the upper part ofa corresponding spray chamber, a cooling coilin each of said spray chambers between its air inlet and outlet and through which the fluid to be cooled is adapted to pass and over which the air from the corresponding air inlet flows downwardly and out through the corresponding air outlet, means arranged in the upper part of each spray chamber abov the cooling coil therein to discharge and distribute a stream of water over thecooling coil therein to wet the exterior .of said cooling coils and to evaporate and absorb heat therefrom, a sump in the bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a precoolingcoil, means arranged to pass a stream of air over'said precooling coil, and means .con-

ducting the fluid to be cooled in series first through said precooling coils and then through said wetted coils.

6. A cooler of the character described, comprising a shell having top, bottom, front, rear and side Walls, an internal battle at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other and said bafiles forming with one another a central plenum chamber bounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said side walls and each leading to a corresponding spray chamber, the side of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and through which the fluid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of water over each of said cooling coils to wet the l exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a casing mounted on the exterior of said shell, an opening in said shell and providing communication between the interior of said casing and said plenum chamber, an air inlet for said casing whereby said exhaust fan induces the flow of a stream of air through said casing, a precooling coil in said casing, and means conducting the fluid to be cooled in series first through said precooling coil and then through said wetted coils.

7. A cooler of the character described, com- J14 prisin a shell ha na em, t am, eal and sidewalls, an internal baffle at each side of said shell and extending horizontally lengthwise 'of said shell and forming with the corresponding side wall a pair of spray chambers arranged one abovetheother and said bafiles forming with one another a central plenum chamber bounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said side walls and each leading to a corresponding spray chambfil, the side of each of said spray chambers opposite its said air inlet being open to said plenumchamber, a cooling coil in each of said spray chambers and through which the fluid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of water over each .of said cooling coils to wet the exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom Wall of said shell, 2, pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a casing mounted on the exterior of said shell, a. central partition across said casing and extending generally perpendicular to the adjacent wall of said shell a distance short of the opposite end of said casing to provide two passes therein, an opening in said shell and providing communication between the adjacent end of one of said passes and said plenum chamber, an air inlet for said casing leading to the end adjacent said shell of the other pass, a precooling coil in said casing, and means conducting the fluid to be cooled in series first through said precooling coil and then through said wetted coils.

8. A cooler of the character described, com prising a shell having top, bottom, front, rear and side walls. an internal bafile at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other and said baffles forming with one another a central plenum chamber bounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said side walls and each leading to a corresponding spray chamber, the side of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and through which the fluid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of water over each of said cooling coils to wet the exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said top wall leading from said plenum chamber, an exhaust fan in said exhaust duct, a casing mounted on the roof of said shell at each side of said exhaust duct, an opening in said shell and providing communication between the interior of each casing and said plenum chamber, an air inlet for each casing whereby said exhaust fan induces the flow of streams of air through said casings, a precooling coil in each of said casings, and means conducting the fluid to be cooled in two streams each stream of said fluid passing in series first through one of said precooling coils and then through the wetted coils on the corresponding side of said shell.

9; A cooler of the character described, comprising a shell having top, bottom, front, rear and side Walls, an internal baffle at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other and said bailles formingwith one another a central plenum chamber bounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said side walls and each leading to a corresponding spray chamber, the of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and through which the iiuid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of Water over each of said cooling coils to wet the exterior of each of said cooling coils and to evaporate and absorb heat therefrom, a sump in said bottom Wall of said shell, a pump recirculating said Water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a preccoling coil, means arranged to pass a stream of air over said precooling coil, a

means conducting the fiuid to be cooled in series first through said precooling coil and then through said Wetted coils, and an oil separator in said fluid conducting means between said precooling coil and said wetted coils.

10. A cooler of the character described, com prising a shell having top, bottom, front, rear and side walls, an internal baiile at each side of said shell and extending horizontally lengthwise of said shell and forming with the corresponding side wall a pair of spray chambers arranged one above the other and said baflles forming with one another a central plenum '16 chamber bounded by said top, bottom, front and rear walls, a plurality of air inlets in each of said side walls and each leading toa corresponding spray chamber, the side of each of said spray chambers opposite its said air inlet being open to said plenum chamber, a cooling coil in each of said spray chambers and through which the fluid to be cooled is adapted to be passed, means arranged to discharge and distribute a stream of water over each of said cooling coilsto wet the exterior of each of said cooling coils and to evapcrate and absorb heat therefrom, a sump in said bottom wall of said shell, a pump recirculating said water from said sump to said discharging and distributing means, an exhaust duct in said shell leading from said plenum chamber, an exhaust fan in said exhaust duct, a precooling coil at each side of said casing, means arran ed to pass a stream of air over each of said precociing coils, means conducting the fluid to be cooled in two streams each stream of said fluid passing in series first through one of said precooling coils and then through the Wetted coils on the corresponding side of said shell, and a pair of oil separators in said fluid conducting means and each arranged between one of said precooling coils and the wetted coils on the corresponding side of said shell.

CHARLES N. DEVERALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,166,397 Deverall July 18, 1939 12,213,622 Carraway Sept. 3, 1940 2,247,514 Mart July 1, 1941 2,251,261 Coey Aug. 5, 1941