US2668421A

US2668421A - Refrigerator car with fan and brine circulating system

Info

Publication number: US2668421A
Application number: US218350A
Authority: US
Inventors: Thore M Elfving
Original assignee: Union Asbestos and Rubber Co
Current assignee: Union Asbestos and Rubber Co
Priority date: 1951-03-30
Filing date: 1951-03-30
Publication date: 1954-02-09
Anticipated expiration: 1971-02-09

Description

T. M. ELFVING Feb. 9, 1954 REFRIGERATOR CAR WITH FAN AND BRINE CIRCULATING sYsTr-:M

Filed March so, 1951 2 Shee'hs--SheefI l INVENTOR. THORE M. E/ FV//VG Feb. 9, 1954 T M, ELFVlNG i 2,668,421

REFRIGERATOR CAR WITH FAN AND BRINE CIRCULATING SYSTEM Filed March 50, 1951 2 Sheets-Sheet 2 z l f l/l//l/z/l/ 1/ 11i/,fl /////,l

IVENTOR.

Patented Feb. 9, 1954 gieizfl REFBJQERATOR GAR Wirn v.FAN .AND .BRINE Een@ @Eltrilig een AAS Mateo., C

Appliootionmamhfan, 1951, serial-No. `218,350

The Apresent .innentionnrelates .to railroamrefrigeratorcarsusing ice `or a-.mixtureof iceend saltasrefrigerant. It .hasiforits purpose ,Stopwvide a .refrigerator ...can ,which can maintain .a constant .lolw .temperature -`inclepenfilent.0f the amount of -iee andsalt in .fthe-.ice bunkers ,and independent ofthe .carbeingin motion tir-.not

According .to .the.,.invention .the temperature inthe car @an .be l-thermostatically ...regulated .as ifothecar was .provided .with .mechanical refrigeration. g Like ,presentrefrigeratornar.lhelwest Ytemperature.obtainable in .a .ear .,willtbede.- pendent-.upon-.the temperatureof theieland salt mixture., orothereirigerant inthe.l ice bunkers, but in other respectsthepresent .inventiomeliininates many. of the .weaknesses foundinrailroadrefrigerator oarsofV the ,presentce-bunKer type- Arefrigeratorcaroaccording.to thepresentinvention .can `use .either eend.. ice:l bunkers .Qrfcrerhead .ice ;bunkers..or..both. .-As ,an Lexernplt.,.the invention -.wi1l.b.e .described in, connection e-Wfh the -accompanyingidrawings as...app1ied to ...a 12.6- frigator .car Yof the. .end -.ice .;b.i inlier..type.

Inthe drawings:

vFigure Q1 .shows I.a longitudinal... section through one-half. .of `re, 1 refrigerator .caraccording 1.1.10 @the invention, and

Figure 2 shows a cross section View Qfrtkietar as.-.sho.wn inFigure 1.

.-In :these draw-mesa conventional. refigelatcr car'. is, shownosocmposed. of. wneelsepresentcd by l,..underframe 2,.in.s.u.lated 4ffioor t? end. walls e4,- .insulatedgside.walls-...inn ceiling i6. r`Said.v refrigerator car@ indicated .a hconventional...structiiral .'.hiilkhead a forming aspace.inetherendeof said .ca-r; known to theitrade as anlendoiceibunkerg 8. Thefwalls of A.said ice hunker.f..are\formedfbyethe L.car .end linings, side lining :l9,.fand.structuralibulkhead 1. 'The ceilingis .formedmbyfthe car,ceilingfM andthe/floor is ormedhyaooor panrtZrM/'hich is providedwithradrain :113. through a watenseal M. '.Also indicated lare hatch.,.openings [5,.and floor.. racks .|i6,.a1l voiazvhich. wemelt-known.

.iInside .of said ice .bunker .-thereis ...constructed anzice tank Il .directly connected.withztliefhatcl'i` openings l5 insuchia waygthatlan-air passageol is ...provided over.:the.,ioezitankfaround.said,openings. -The` ice .tankoisfso iarrangedias .atol provide ani air-space le `and. .an airochannelfi l)..betii'zeen the-ice .tank vandi-,theocar .structureat Alool,li...the` side and end walls. yFIheaieetank..A I Lis.water-ztight except for the openings ..21 Y@for f.. brine .'overow. The iceitankisi-supported by Y- the-structuralabulkhead-#Land across beainZ. 11n-tiledcetank-Lis.4

' theicegrate.. At thecenterof thehcarthetloettom of. tneice tank is.proridednitha-ri1tni valve 2E -for.emptying.and cleaning tlietank.

`Asseen fromv v,the .abus/...e .siescrinjiiQn .flle QC tank .u is ,surroundedon all...sideswith arassages through .which .air .can be Circlllfifdt .159.1 cooling-bycontactivth the. coldsdes Qf.. .htnllk- Thisotersa considerablecoolingapaictyiwhik however, nis `rvery .much .increased :by ,the -blili circulating .system added 4, to the bunker .iiQQOrdf ing .to .the invention. .Such a .crculatingwtcm can .be .provided .with ,cooling .Sur-fa .large enough .to .obtain the .total .cooling ,Capacity needed for .a car .of this type. The brine .is circulated Joymeansof amotor ,driven pump 12J which takes .the ,brine ...throueh..th.e ...pip .2.18 fromthe brine spacef underncath..thc. c.eg

Brine. is .forced fromjtherpump.throngllfflhpip h eat .exchange .unit .19 .consieting of yertiqally arranged;.horizont.al-pipes,.proyided Witnnns. and located inanar `.circulation flue ,en adjacen to the structureobulkhead Land separatedirgnisaid h u1khead..by Y.a wall or .baffle .31 .extendingjironi thesh'ottomwither.bnlkheadmeinbere Y l of. theiippermost horzcntalnnpine- .A A ls point theairrflue Seann .thespace etween the structural,bulkheadmemners commu otherside. ofetheair flue 3.0 :is 10min.. by na. ...wooden lining .3 2 ...Which extends fr bottom; ot nthe.Joulkheadirneiii.IQSJFS. lqthfi ing..33. ...Theliin 4pipes areinstries and tm lorgne .will g'rarjnally raise in temperature .when .11%- ing through .thisair ...cooling system. Thbliile iS brought-back .to the ...ige tank ftliloilg 1.1 .ilhollli 34. .Thispipe ,conductsetnewarm brine to .line top ofhtloetank @between `-.the hatch ...openings Iand leads.. across ther-tank etc' the outlet spray ...pipe 35, from -whicnthe-brine issprayed oizerthei an-salt mixture-in the tank. v.'lhe=,..`ri. eated brine melts `somelof the ..ice,.additional' saltis dissolved`,andithe circulation..is..repeated.

fTh'e air isj accbrdngl to .theiinventom ..irculatedlaroundthetotalcoolngystemhyemcens of.,electric..fans;3.i. located .1.1L .hQlQSi 31,1238. fm housing .1:33. -.'1`..h.e .air .circulation between ,eine commodityspaceiofthe carena-,the .COQlill SYS- temidescribed .aboye-.is carried..oi its.inthe sfollowing LWay Below .the:;load;inxthe car thetairmis cifrciilateiiiny :thespac.e...between rthefflocr .edck

` 3'82'andotheaocr-rack.. t6.;andislpulledzhyetheffan into the cooling system at the bottom of the bulkhead. The air now is divided in three separate Ways. One part of the air coming from the commodity will go the shortest way through the air flue 30' passing over the brine circulating coil system. This lowers the temperature of the air before it reaches the upper part of the vertical flue where the fans force it out into the commodity space again. Another portion of the air flow goes between the bulkhead structural members between the ice tank l1 and the wall 3|. large cooling surfaces the air flow through this As this passage of the air does not offer Y area is restricted by a restriction member 39.

This member 3B does not prevent air circulation by free convection in case the fans are not operating. The remaining portion of air goes under the ice tank and passes around the remaining three sides of the tank up to the top of the bunker, from there to the fans and out over the load again. All three passages described above offer a certain cooling eiect to the car, but it will be shown in the following description that the major portion of the necessary refrigerating capacity will be provided by the brine circulating nn pipe system. This system'will maintain the same brine temperature, as long as any ice remains in the eutectic brine in the tank. It is therefore capable of maintaining a reasonably constant rerigerating capacity as long as the brine pump and the fans are operating.

e As shown in Figure 2 of the drawings, the

brine circulating system connected` with the ice tank is seen from the car after removing the wall 32. I2 is the floor pan with the drains I3 and water seals I4. The brine circulating pump 2l with the motor 40 and the inlet pipe 28 is located between two bulkhead structural members in an opening in the wall 3i within the bulkhead sections and the air flue 30. The pump is therefore readily accessible from inside the car through an inspection opening in the wall 32. The pump is located underneath the n pipe system and the. whole system will drain itself through the pump,

and the inlet pipe 28 when the brine in the ice tank is drained off through the cut off valve 2B.

shown in Figure 1. This automatic draining oi the cooling coil system and the pump is very important for the reliable operation of the brine circulation as sedimentation inside the pipe system or inside the pump should be avoided. The

heat exchange unit 2s is secured inside the airflue by means of wooden members 4t which are bolted to the bulkhead structural members. These members 4i also serve as'stringers for securing the plywood wall 32. In Figure 2 are also shown the fans 3S located in the openings 31 as well as the outlet pipe 34 leading from the fin pipe system to the spray pipe 35 which runs practically the full width of the tank. The upper layer of the ice and salt mixture in the tank is thereby contacted by the comparatively warm brine coming from the cooling coil system.

The refrigeration capacity needed for a heavily insulated low temperature car is usually estimated to be approximately 20,000 B. t. u.s/hour. As previously stated it is possible in a refrigerated car, according to the present invention, to provide the brine circulating system added to the bunker with cooling surfaces large enough to take care of this needed refrigerating capacity. This is accomplished -by using iin pipes and by balancing the brine and air circulation in order that a correspondingly large heat flow takes place from the air to the fin'pipe system. and from the 75. placed in a suitable position in the commodity n pipe system to the brine, and finally to the ice and salt mixture in the ice tank. The refrigerating capacity to the air represented by the surface of the ice tank itself may serve as a margin of safety for extreme conditions. A refrigerator car according to the invention should have the following approximate data as far as the cooling system is concerned: The ice tank capacity should be about the same as for conventional cars of the end bunker type, that is approximately 12,000 pounds of ice plus 30 per cent salt by weight. Because of the ability of the invention to maintain full refrigerating capacity until all the ice is melted this amount of ice will be suflicient for approximately 60 hours of operation. With the above proportions of ice and salt it will be possible to obtain a temperature in the ice tank of about -5 degrees Fahrenheit, which temperature will be maintained in the brine entering the brine pump as long as any ice is left. It is assumed that an average temperature difference of 10 degrees Fahrenheit between the coil system surface and the circulating air in the air flue is obtained and it can also be assumed that the heat transmission coeiiicient between the fin pipes and the air will be 5 B. t. uis/square oot/hounper degree, F., which corresponds to the air velocity obtained with a fan capacity of 3000 C. F. M. or more. We nd then that the cooling surface needed for transferring 20,000 B. t. u.s per hour is about 400 square feet. Approximately half of this surface is obtained with a nn pipe system as shown in Figure 2 which is composed o 3A" pipes provided with suitable fins.

If a brine temperature rise of 3o F. is allowed during the passage of the brine through the vcoil system it takes the circulation of 400 gallons of brine per hour to deliver a refrigeration capacity of 10,000 B. t. u.s which gives a brine velocity inside the pipes of approximately 300 feet per minute. The pump and motor capacity should be chosen according to this requirement. With the above dimensions of the cooling coil system together with the cooling capacity of the tank itself it should be possible to maintain a temperature in the car of 5 F'. or lower under all conditions.

The brine pumps and the fans, as employed according to the present invention, are driven by electric motors which are connected by the cable 42 with an electric generator driven by an internal combustion engine. Figure 2 shows the electric motor for the brine pump 21, and Figure 1 shows the motor 43 for the fan 36. Figure l also shows the engine-generator unit M as located on a suspended platform 45 which is hung between the underframe cross tie d6 and the underframe cross beam 41. The enginegenerator unit is provided with an intersection door 48 having grills 49 for air circulation. The engine has a fuel tank 50 with a, capacity large enough for driving the generator at least 10 days, while the car is in transit across the country. A generator for supplying fan and pump motors, according to the invention, with electricity of a suitable voltage has only to produce between 1 and 2 kilowatts, and an internal combustion engine of 2 to 4 horsepower is sufficient for driving the generator. This engine should be of the air-cooled heavy duty type and providedv with a starting battery, starting motor, and an automatic starting control unit for thermostatic operation. A selective thermostatic control 5I reageer:

mun determined bytrfete' h erant in the ice bunkers. en usingice ands'al't with an eute'ctic temperature of about* "-155 kli'. the Iiinizriding'tenjlpe'ratt'lre` in the car will probably be 2 F. or *slightly below. 4The brine tand air circulating system jcan vbe placed in 'operation a's "scoh `as 'thejcar has been ticed, thereby reducing the normal precooling time considerably.

l:refrifgerator 'car cooling "system, l'according to the invention, is superior to jmechanical'r ef rirge1jation 'fvvith a `compressor unit inthe Yrespect 'that ice and salt inthe lice 'bunkers oiersfa'soirce `of refrigeration which isfavailable even iiv the'jc'om'- bustionfen'ginejrf tlef'generator or other mechanicaltpa'rtshf 'thefsystemfsh'ould fail. The refrig eration capacity of this system, when 'the brine pump' or the 1f ans 'arenot operating, 'is small 'come pared with fthe refrigeration capacity when the cooling jfcoil system isw'orking according 'to the abv'e description ,AI-Iowever, "theV refrigeration with natural 'convectic'nfoi the airis 'sufficient vrin rho'stcases to prevent damage tothe commodity. The Vair :Flow "around 'thebnker system, when the 'fans are `standing "'still, will 'be in `reverse to the air Eiow 'described'above. Gravity "dinierence will cause theairtoente'r th'es'ystem through the fan lholes and `-flow"do'wriwa'rdsaround the tank between j the bulkhead structural members and through theairiue forfthe'n' pipe System. "Rest'riotions'in the `air passages will'h'ave'less'efect on `slow 'moving Aair than "on forced air 'and a bunker system, according lito `the invention, fwill therefore oier equal refrigeration, when "fans `rid pump are not loperatir'rg, toirdiaryend bunker'car's now genral use.

A-brine circulatin'gf'cooling system, according tothe invention, canbe'lccated'orfarranged in I'a'riy diierent ways.l IForced brine circulation combined with forcedfaircirculatifon makes it possible to arrange l'the -iin "pipe "co'oling is'ys` tem' almost 'anywhere in the car. 'A` verticaln pipe system similar to that 'desc ribed"above'fma37 be 'placed' in 'afw'all flue behind :the' bunker "or at the sidewalls. It is `also possible to arr ng'e'th'e brine circulating system along the "ceiling of fthe oar,` above `the loading'spac'ead 'between the bulkheads. l

The cooling"'coilsystemiadd'd to" the rbnlnfer in order to'inorease therefrigeratofcapacity"'of the ca r, according to the invention, can"A 'c beof'the s'elf -circulating typegthat is:a'himetically'fsealed heat transfe1""s'ystemfus`" g'"a' volatile 'refrigerant s'uclias ammonia' for n. In"thi's'casea brine pump would not be"reqird,`a1d"th`e' enginegenerator unit has' onlyv to supply' electricity to the I'fan for circulating 'air around" 'the preferably such a 1h ermeti'callyl sealed circulating'sys'ternas Wellasa'round theice tinker, l

LA@brine-fcirculatngssyste fonc'ooling'"tleair staff-tie an' ne! ature'orf the refrig'- can faccoin'g 'te' 'the invention I* aise te cih-the spray lor wet surfaceftype, inwhich case the brine i's'pmped from the bottom of the ice tank upto a spray pipe located in a vertical air fluev through which air is circulated. After leaving Vthe spray pipe the brine may-either Yfall 'in small drops throughth'e air lor `drizzle Iover 'preferably-"corrugated surfaces Iover which the 'air is lpass-ing while being lcooled. The pump brine maybe divided "in two Ways, one part beingspra-yedover the toplay'er of ice and "salt 'in the ice tank, :the other part passing the aircooling iiue back to the bottom or 'lower-part cf theicet'ank.

Thegenerator lu'sed'fo'r 'supplyingelectric power to the pumpsand/or fans used inthe V'cooling system, according tofthe invention, can alsobe driven 'from the wheels Acf `the car in which' case the generator Ahas to be provided with a storage battery A'for A'operating `the pumps and/or "fans when-thecai` is standing still. The thermostat has in this 'alt'ernativeonly to operate fa 'switch'in theel'ectric circuit.

"Wl1il`ehave, 'for 'the 'sa-ke'of lclearness and in order Ato-disclose theinvention sothat `the same can -r`be 'readily understood, described "and"`illus` trated specic devices and arrangements, 'I `desire'to have lit understood that this inventions not llimited to the 'specic means disclosed, but

may be Aembodied in -other'ways thatiwill "suggest themselves Ito lpersons skilled in the art. It is believed that this invention is'new and all such changes ascome Withinthe'scope of the` appended' claimgare to be considered-'as partefthisfinven-l tion.

4'Having thus described my invention, what 'I claim and desire to isecureby Letters EJPatent :is:

l. In a refrigerated-railway canhavinglannsulated lading accommodating jspace; the combination ofl 'anice and-brine "accommodating tank mounted within sai'dcar atl one V4endend spaced from `the top, -bottoinyend and side "walls `thereof -for -free passage of air therearound,"a-baiiie disposed Lvertically'and transversely-of saidcar body -and terminating '-in spaced *relation 'with the fiioor andv ceilingy of the oar to -provide "anair' passa'sway7i adjacent vthe inward `side-of *said icev tank, aheatwexchangelunit mounted' atthe` other side fof-said baffle and within 'the Kupper and lower limits thereof, a brine lpump for 'circulating brine v"from the bottom'of "said tank' through Isaid heatexchange'unit 'and discharging' same as-a sprayatithe top"of"said icetank, an insulating end 'wall mounted `in `inwardly spaced relation with respect to'said heater(- change unitwhich denes` the klimits of thef'ladingspace and provides an aircirculating passageway through whichair will circulate over said heat exchange unit,'said end VWall being disposed 'withfitsv bottom edge in spaced Hrelation with floor of the car and having ran"apertme locatedabove vsaidheat exchange junit, fan electricI fan mounted in the'aperture'insaid'end Walll cooperating' relation 'with 'said 'baflie'ior maintainingr a' forced circulation of airfrorn thelading space Vabout-said ice tank'and .over said' heat,

exchangeiunit, and means at' the lower .edge of saidbatlieffor directing themajor portion of the fan circulatedfair over said v'heatexchange unit.

2. vIna'refrigerated'railway car'having an insulated lading accommodating space; the-com bination of Aan ice and "brine accommodating tankm'ounted at one end "Within said car and spaced frointhetop, bottomfend and vside Vwal-ls thereofto'provide'for'a'free ycirculation of air 7 therearound, a vertically disposed baille extending transversely of said car body and spaced from the noor and ceiling to provide an air passageway adjacent the inner side of said ice tank, a finned pipe heat exchange unit mounted at the side of said baffle remote from said tank, a brine circulating pump for circulating brine from the bottom of said ice tank through said heat exchanger and discharging same as a spray over the ice in said ice tank, a heat insulating end wall mounted within said car body and inwardly with respect to said heat exchange unit to provide a confined space through which air will circulate over the iin pipes of said heat exchange unit, said end wall being disposed in spaced relation with floor of the car and having an aperture above said heat exchange unit, an air circulating fan mounted in cooperating relation with said bane and the aperture of said end wall for circulating air from the lading space of said car about said ice tank and over said heat exchange unit, and means for regulating the now of air about said ice tank, the arrangement being such that the major portion of said circulating air will be passed over said heat exchange unit when said fan is operating.

3. In a refrigerated railway car having an insulated lading accommodating space, the cornbination of an ice and brine accommodating tank mounted within said car at one end and spaced from the top, bottom, end and side walls thereof for free passage of air therearound, a baille extending transversely of said car body in spaced relation with said tank and spaced from the floor and ceiling of the car to provide an air circulating passageway about said ice tank, an insulating end wall mounted in inwardly spaced relation with respect to said baffle which denes the limits of the lading space and provides an air circulating passageway remote from and independent of the passageway about said ice and brine tank, said insulating end wall being disposed with its bottom edge in spaced relation with iloor of the car and having an aperture at its upper edge, an electric fan mounted in the aperture in said end wall, a heat exchange unit mounted in said latter air circulating passageway, a brine pump for circulating brine from the bottom of said tank through said heat exchange unit and discharging same as a spray at the top of said ice tank, and means at the lower edge of said baffle for limiting the flow of fan circulated air about said ice tank when said fan is operating.

4. In a refrigerated railway car having an insulated lading accommodating space, the combination of a bulkhead having an opening at its top communicating with the interior of the car and forming a chamber for an ice and brine accommodating tank at the end of the car, an ice and brine tank mounted within said chamber in spaced relation from the top, bottom and side wall of said chamber for the free passage of air therearound, a vertical wall disposed in inwardly spaced relation with said bulkhead and providing vertical air circulating passageway, a circulating brine heat exchange unit mounted in said air passageway and disposed between the upper and lower limits thereof, a brine circulating pump for maintaining a circulation of brine downwardly through said heat exchange unit and discharging said brine as a spray over the ice in said ice and brine accommodating tank, and means for maintaining a forced circulation of air upwardly through said air circulating passageway from the bottom to the top of said lada ing space of the car, whereby the air circulating over said heat exchange unit will ow in countercurrent relationship with the brine circulated through said heat exchange.

5. In a refrigerated railway oar having an insulated lading accommodating space, the combination of a bulkhead having an opening at its top communicating with the interior of the car and forming a chamber for an ice and brine accommodating tank at the end of the car, an ice and brine tank mounted within said chamber in spaced relation from the top, bottom and side wall of said chamber for the free passage of air therearound, a vertical wall disposed in inwardly spaced relation with said bulkhead and providing vertical air circulating passageway, a circulating brine heat exchange unit mounted in said air passageway and disposed between the upper and lower limits thereof, a brine circulating pump for maintaining a circulation of brine downwardly through said heat exchange unit and discharging said brine as a spray over the ice in said ice and brine accommodating tank, and means for maintaining a forced circulation of air upwardly through said air circulating passageway from the bottom to the top of said lading space of the car, whereby the air circulating over said heat exchange unit will flow in countercurrent relationship with the brine circulated through said heat exchange, said air circulating means being disposed and arranged so as to not interfere with a free convection circulation of air around said ice and brine tank and over said heat exchanger unit when said air circulating means is not in operation.

6. In a refrigerated railway car having an insulated lading accommodating space, the combination of a bulkhead having an aperture at its top communicating with the interior of the car and forming a chamber for an ice and brine accommodating tank at the end of the car, an ice and brine tank mounted within said chamber in spaced relation from the top, bottom and side wall of said chamber for the free passage of air therearound, a vertical wall disposed in spaced relation with said bulkhead and providing narrow air circulating passageway extending throughout the width of the car, a circulating brine heat exchange unit having horizontally extending nned tubes mounted in said air passageway and occupying the space between the sides and the upper and lower limits of said passageway, brine circulating pump for maintaining a high velocity circulation of brine downwardly through said heat 'exchange unit and discharging said brine as a spray over the ice in said ice and brine accommodating tank, and means for maintaining a forced upward circulation of air through said air circulating passageway, whereby the air circulating through said passageway and over said heat exchange unit will flow in countercurrent relationship with the brine circulated through the iinned tubes of said heat exchange unit.

'7. In a refrigerated railway car having an insulated lading accommodating space, the combination of a bulkhead open at its top and forming a refrigeration medium accommodating chamber in communication with the interior of the car, a metallic ice and brine tank mounted in said chamber in spaced relation with the top, bottom, end and side walls of the car, a vertical wall extending transversely of said car body in spaced relation with said bulkhead and forming an air passageway throughout the width of the car, a heat exchange unit mounted between said bulkhead and said vertical wall and within the upper and lower limits of said vertical wall, a brine circulating pump having connections for withdrawing brine from the bottom of said ice tank and circulating said brine downward through said heat exchange unit and returning said brine as a spray at the top of said ice and brine tank, said vertical wall being terminated short of the oor of the car and having an aperture above said heat exchange unit, and an electric fan mounted in cooperating relation with said bulkhead and the aperture in said vertical wall for maintaining a forced circulation of air from the lading space of said car about said ice and brine tank and through said vertical air passafeway in countercurrent relation with respect to the ow of brine through said heat exchange unit.

8. In a refrigerated railway car having an insulated lading accommodating space, the combination of a bulkhead open at its top and forming a refrigeration medium accommodating chamber in communication with the interior of the car, a metallic ice and brine tank mounted in said chamber in spaced relation with the top, bottom, end and said walls of the car, a vertical wall extending transversely of said car body in spaced relation with said bulkhead and forming an air passageway throughout the Width of the car, a heat exchange unit mounted between said bulkhead and said vertical wall and within the upper and lower limits of said vertical wall, a brine circulating pump having connections for withdrawing brine from the bottom of said ice tank and circulating said brine downward through said heat exchange unit and returning said brine as a spray at the top of said ice and brine tank, said vertical wall being terminated short of the floor of the car and having an aperture above said heat exchange unit, and anelectric fan mounted in cooperating relation with said bulkhead and the aperture in said vertical wall for maintaining a forced circulation of air from the lading space of said car about said ice and brine tank and through said vertical air passageway in countercurrent relation with respect to the flow of brine through said heat exchange unit, said air circulating means being disposed and arranged so as to not interfere with a free convection circulation of'air around said ice and brine tank and over said heat exchanger unit when said air circulating means is not in operation.

9. The improvement in a refrigerated railway car having an ice bunker at one end which comprises, a metallic tank within said bunker and spaced from top, bottom and side walls thereof to permit a free circulation of air thereabout, said metallic tank being charged with an eutectic mixture of ice and salt, a circulating brine heat exchange unit disposed inwardly and adjacent said metallic tank, a vertical and transversely extending partition at each side of said heat exchange unit forming two paths for the circulation of air from within the lading space of said car, one such circulation being around and about said metallic tank and the other over and about said heat exchange unit, pump means for circulating brine from the bottom of said tank through said heat exchange unit and returning said brine as a spray at the top of said metallic tank, an air circulating fan at the upper end of said spaced vertically disposed and transversely extending partitions, and means whereby a major portion of the fan circulated air will pass over said heat exchange unit when said fan is operating, said means being such that it will not materially interfere with a full and free convection circulation of air around said tank and over said heat exchange unit when said fan is not operating.

l0. In a refrigerated railway car having an insulated lading accommodating space, the combination of an ice and brine accommodating tank mounted within said car at one end and spaced from the top, bottom, end and side walls thereof for free passage of air therearound, a bulkhead defining a chamber within which said tank is disposed, said bulkhead having an air passageway at its top communicating with the interior of the car, a heat insulating end wall mounted in inwardly spaced relation with respect to said bulkhead defining the limits of the lading space of the car and providing an air circulating passageway remote from an independent of the passageway about and adjacent said ice and brine tank, said insulating end wall being disposed with its bottom edge in spaced relation with floor of the car and having an aperture at its upper edge, a fan mounted at the aperture in said end wall for maintaining an upward circulation of air through said passageway, a heat exchange unit mounted in said air circulating passageway, and a brine pump having conduit connections for circulating brine from the bottom of said tank and downwardly through said heat exchange unit and discharging said brine as a spray at the top of said ice and brine tank.

THORE M. ELFVING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 927,595 Place July 13, 1909 1,040,739 Nilsson Oct. 8, 1912 1,093,075 Porges Apr. 14, 1914 1,822,305 Moore Sept. 8, 1931 2,115,472 Sargent Apr. 26, 1938 2,187,277 Minard Jan. 11, 1940r 2,198,822 Karge Apr. 30, 1940 2,267,456 Glenn Dec. 23, 1941