USRE22678E - Refrigerating system - Google Patents

Description

Oct. 9, 1945.

O. C. IRWIN REFRIGERATING SYSTEM Original Filed Sept. 12 1952 3 Sheets-Sheet 1 mm .mI m W n I ,A 0 Y B Re. 22,618 I Oct.

Original Filed Sept. 12 1932 3 Sheets-Sheet 3 .mm mm H. wo T I 1 J 2 I a "m m \N N @m/ V w (v/v vvv \l v Q E 8 3 Wm Reissued Oct. 9, 1945 UNlTED STATES ATENT OFFICE REFRIGERATINGUSYSTEM Oliver 0. Irwin, deceased, late of New York, N. Y.', by Standard Cap 85 Seal Corporation, assignee, New York, N. Y., a corporation of Virginia Original No. 2,31 6,791.dated April 20, 1943, Serial No. 632,740, September 12, 1932. Application for reissue April'19, 1944, Serial No. 531,846

I 11 Claims. The invention relates to refrigeration systems and more particularl to a system of mobile re-' fri'geration. Insofar as this application is concerned, the invention will be described in conjunction with refrigerated railway cars particularly. butit will be apparatus that certain phases of the invention will be applicable to refrigerated motor trucks and other units of mobile transportation. Y I Heretofore, railway cars have been cooledby the time hon'ored ice and salt method or by the useofevaporating chemicals or by the use ofmechanical refrigeration machines wherein the motor, compressors, condenser, evaporator, etc, are all carriedby the car.

These former systems have many disadvantages such as the matter of weight, unreliability in emergencies, unreliability of mechanically moving parts, etc, and etc. I

It is one objectof the invention to provide .a system of refrigeration for mobile units wherein there are no moving parts on the unit.

It is another object of the invention to provide. such a system wherein the weight of: apparatus and refrigerant becomes a negligible factor in the total weight of the mobile unit; and

likewise wherein the useful load carrying space' occupied by the refrigerating equipment is also a negligible part of the total useful spaceof the unit.

..The foregoing objects of the invention are in part accomplished by the particular systemand improvements hereinafter disclosed and in part by the particular apparatus used on the mobile unit. As to the refrigerating system'used, it is basically an absorption system. vHowever, the

absorption system in the case is divided into a' plurality of units.

It is a further object of the invention to pro- '4 vide an absorption system wherein the total ref frigeration cycle is performed in separate places.

It is a; still'further object of the invention to provide a system of mobile refrigeration using the absorptioncycle whereina portion only of the cycle is performed on each mobile unit.

It is an even further object of the invention to provide a system of mobile refrigeration wherein a portion of an absorption cycle of refrigeration is performed on each mobile unit and a plurality of such units cooperate with a central depot wherein the remainder of the absorption cycle. ofrefrigeration is performed.

It is an even further object of the invention to providea system of mobile refrigeration wherein sorption cycle wherein the absorber is used circulatory system. V h

Other and further objects of the invention will the refrigerant used cooled.

It is still'another objectof the inventior'i'to to provide a system of refrigeration using the ab to pre-cool the condensed refrigerant. a

It is still another object of the'invention to provide a system of mobile refrigeration wherein extensive use is made of finned surfaces on the mobile unit.

It is still another object of the invention to provide a system wherein the control of the temperature of the mobile unitis governed by the pressure in the refrigerant supply tank.

It is an even further object of the invention to provide a cooling arrangement for mobile units using an absorption system of cooling and an air be apparent from the following description taken in conjunction with the accompanying drawings,

wherein r 1 p v Figure 1 is a diagrammatic layout of. so much of a refrigerating system and apparatus as is located at the central depot;

Fig. 2 is a diagrammatic illustration of the body portion of a railway car, parts being broken away and parts being. shown in section ,to facilitate the illustration of the application of the invention thereto;

Fig. 3 is a vertical section on the line 3-3 of Fig. 2;

Fig. 4 is a partialtop plan view of refrigerat ing mechanism taken with the topof'thecar body removed; 1 n Fig. 5 is a vertical section of an automatic con.- trol valve; v

Fig. 6 is a diagrammatic illustration of a portion of a railway car with a modified arrangement of cooling surface; and I Fig. 7 is a diagrammatic illustration of a railway fcar with a modified form of refrigeration mechanism applied thereto and utilizing the principle of circulating cooled air. I

In absorption type refrigeration machines, the cycle of the process of producing cold may be stated as follows: There is introduced into a generator or still a liquid which is'a combination of .a refrigerant and an element which absorbs the refrigerant-respectively ammonia and water: usually.. Heat is appliedv to the generator 'su'ffi-.

cient to boil off the refrigerant'which passes into a condenser in the form .of a vapor. The convdensed refrigerant in turn passes to an expander or evaporator. Here the refrigerant is again on the I mobile unit is pre I vaporized and absorbs the heat from the air or other medium surrounding the evaporator. The refrigerant leaves the evaporator and is returned to the generator, but interposed between the evaporator and generator is an absorber. The absorber contains the so-called weak liquor (the residue rom. the sens-rater artert e re r eran is boiled on?) and intende -absorber is .alsoz'introduced the'reirigerantboming from the evaporator. The two unite and thus the liquor leaving the absorber for the generator is a strong liquor by which is meant a liquor containing-astrong charge of refrigerant or ammonia,

Of course. there ay b arieurfliother elsinents;

introduced into this simple systemisugh asa heat; exchanger and a pump for getting the liquid from,

the absorber into the still, etc. I

One step of the invention contemplatesplncing on the mobile unit only so much of the apparatus of an absorption system as is necessary to-do-the work r coolinghe mob le and, leav n a a separate, detached and probably stationary. central unit ai tnat apparatus having. lie-d with th rec amation'e d egene tion of th reins;

rec amation poe hnh the b orption. system.

the g nera or; ndenser. absorber. and

related elements. Whena railway: car istqhegin itsrnn. from one of; these-central .dep.ots,i.anhyrbhe ammenia is ntr du ntone stora e nk' ahsii weak; li u r is intr duc d. into. the oth r storage tank in between which is the evaporator. Ohlr samueh char e: s, intro uced as has. pr det mined. to. hes iieieut for. h Parti ul r intended run plus whatever amount. deterned u nas a afety-fact on.

a h end. f. the run there. will be ocat d Q S-Qi t e e entral del e- 's When t ailway car reach s that. oint detac a le h se cone tions will be made to the respective storage. n the railway car. and thev contents. thereof pumped out and into appropriate storage. tanks at the. centra d qt. The car can-th n. e filled nd sent units way immediately. at the central depot the charge received from the condenses the; water vapors and returns them densed water; thedehydratorbeing tipped at an a s p ssed nt he generator where. the refngerant is boiled off, passed into a dehydrator, d, nt a condense the anhydrous ammonia p ssinsdhQedr int tora e. t nks... The W ek.

7 iquor goes from thege crate v t .v the heat ex.-

ng nd em he-hea exehan er nto. aw ak qu r torage ta k. P ea e no tha cer a n details or thej xst m are .not referred to. in. this general description 'b it wiillbe brought will hereinafter.

nother step of h n en on, apart it m the refrigerating system itself is the reirigerant it..- f is gr e to. a v y ow. tem atu e before being introduced into the railway can The weak. liq or-m y or may 9 heme-cooled. One. pridva e i'th s reeepol ns isthat the e is n r e nto the. ra lway ar or mobil m n n y o u r r e antas s necessary for the ctu cooling he. a and naneof the .refri n b s d; 1 1? in wering t etemneratu e the dehydrator 21.

of the refrigerant itself, as will be explained more fully hereinafter. It is at once apparent that anything that reduces the amount of refrigerant that has to be carried upon the railway car is advantageous both from the standpoint of space occupied and weight carried.

Reterrina to Ri l .0; he sha ins which shows in outline, so much oi the absorption refrigeration system as is intended to be located at the central depot, a generator is indicated at H. The source of heat in the generator is a coil of pipe notshown but having the ends thereof re- .spectively connected to the inlet pipe l2 and the 7 outlet. pipe; I} that. are in turn connected to the miter Moi? a. steam heating plant IE, IS indii asteam. trap and IT a shut-oil valve, all of in the. generator 11: is sufficient to boil. Of! the mm nia. here r eerant r tested to y way of example a d the; ammonia vapor thus produced leayes heee r hn hsh theni'pe en eri Th numcse of the deh'y d tor is to rem v ny Water MQPQ IS th t may pass from the generatorthroughjbe pipe [9 form of dehydrator may be used and for purposes. of illustration adeirydrator has been shown that to-the generator. The. dehydrator 21 is water cooled; the water circulating coils (not shown) in the dehydrator being connected to the inlet and 7 outlet pipes aud t!) respectively that are in,

turn connected to a source of water supplyjfIfhe water that is condensed in the dehydrator is re-. turned to the generator through the return line 2t which contains a trap-25m prevent the escape of vapors from the generator through the conangle as. shown.

The ammonia vapors leave the dehydrator through. the pipelt -and enter thecondenser 21.

cooling water through the inlet and outlet pipes 28181151 23. linitheicondenser the ammonia vapors are. completely: condensed and leave the condenser thnough. the pipe M1entering: oneor=theother of a pair of storage tanks 32, 33, depending pon, the. condition. .of the valves... and =35 renect veln, g .1.

,lieet rn ngw tov the-generate 11:, after the ammaria .hasbeen boiled: .off' thev strong liquor and remains is what is. known .as-a. liquor. The e k 1. 1 492 is; waten-izontainmg a small: percent-- age of ammonia. The weakest liquor isoficourse The. r n liquo to. r g ner ted .(rec eived. from the trucks) iS- stored; in the: 1H;

when it is. to baregenerated is w hdrawn from the tank, 4;! through. pipe. 42 aymeanest:

the pump 43 whi hint pduces thlss rongliquor into the tubular. portion of the heatexchanger 31 h ou h the pipe 44. reason for this is that. it is desirable from the standpoint=of economy, of operation to have the strong liquor as hot as possible when it is introduced into the container H and by circulating the strong liquor through the heat exchanger in contact with the hot weak liquor that comes from the generator it is heated and the weak liquor is cooled on. itsway. to its storage tank and cooler. The strong-liquor, leaves the heat exchanger through the pipe 45 which communicates with the inlet pipe J8. leading into the generator ll.

Recapitulating, the complete cycle involves the circulation of the strong liquor from the storage tank through the pump 43 and the heat ex? changer 31 to the generator where the ammonia is boiledoilthe ammonia vapor'passing throuhg the dehydratorZI into the condenser 21.

the storage tank .39 are .now ready for use .in doingthe work. of cooling but,-as explained above,: this portion of the refrigerating cycle is accom-.

plished onth'e railway car ormoble unit as will be hereinafter described. I 1 The useof precooled materials on the railway car has heretofore been referred to. By precool ing the refrigerant is meantlowering the tem-- perature thereof by the amount necessary to bring the temperature ,of the refrigerant itself down to or below the temperature at which-it is:

desired to maintain the unit to be cooled. This :is sometimes referred to as the heatof the liquid which indicates the heat that it is necessary to take from one pound of liquid refrigerant in order to lowerit from the temperature.- atwhich it isfed to the expansion. valve to-the. tempera-' ture at whichit boils in the evaporator. For-ex vThe weak liquor leaves the genample, if it is desired to start with a pound of liquid refrigerant need be placed upon the rail way car as is necessary to do the work of brin ing the temperature of the railway car down to -25"., and maintain'the railway car at this point over thepredetermined period. Thus, the railway car is not called upon to provide either the space for nor carry the load of that amount of ammonia used to lower the temperature -of.the

body of refrigerant down to the pointer useful work, namely 25 F. In the improved systemshown in precooled in which event the valve 46 will be opened and the vvalve.4|..closed. Ammonia gas or vapor will be taken from the tank 32 through the pipe 48 to the absorber 49.- Weak-liquor isv also introduced into the absorber '49 from the heat exchanger 31 through. the pipe 50, it being. necessary to adjust thevalves 5| .in. pipe '38 and Fig. 1, the. ammonia is precooled in first one and then the other of the storage tanks 32 and 33. =2It will .be assumed-that the ammoniain tank 32 -'is being,

the valve in pipe 50 to divide the path of the weak liquor as desired. The ammonia gas or. vapor entering from the pipe 48 meets the inor coils being connected to the inlet and outlet pipes 53 and 54 respectively of the water circulating system.

This operation is continued until. the ammonia remaining in the tank 32 is cooled to whatevertemperature is desired, say 50 F. At that time the valve 46 will be closed and the valve 41- will be opened, whereupon the same operation will be repeated to pre-cool the ammonia in the tank 33. Of course, the valves 34 and 35 will be ad-. It will be noted that ;:the& storage tanks 32. and 33 are enclosed by a thick;

justed accordingly.

casing of insulation 55.

, Normally, in prior art systems, the absorber is located between the evaporator and the stillor generator. The weak liquor .from' the still passes into the absorber from one side and from the other side there is introduced the ammonia: returning from the evaporator or cooling ole-- ment which ammonia is absorbed in the weak liquor converting. it to a strong liquor... The strong liquor is then returned to the still where the ammonia is boiled off and the cycle is repeated as heretofore described.

There also may be introduced between the stilland the absorber a heat exchanger which re-- ceives the hot weak liquor directly from thestill, the weak liquor that goes. to the absorberbeing in that case taken from the heat exchanger,

while circulating .through the interior of the heat 1 $0 exchanger is the strong liquor. coming from the absorber, which being brought into heat ex-- changing relation with the hot liquor from the.

still raises the temperature of the strongliquor prior to its being introduced into the generator.

or still thereby reducing the work of the generator.

It will be apparent from the foregoing. description that the heat exchanger 31 is functioning as in the normal absorption cycle but that the .function of the absorber 49 is different in the However, other means may be used to pre-cool the ammonia, or refrigerant.

proposed cycle.

For example, reference is made to the copending application, Ser. No. 632,741,filed,concurrently herewith.

Inthe proposed system precooling the weak liquor which is also supplied to the railway car is contemplated. For this purpose the weak liquor storage tank 39 is provided with a water cooling system, the inlet and outlet pipes of which are indicated at 56 and 51 respectively. Also, the weak liquor storage tank is entirely enclosed by heat insulation indicated at 58.

The foregoing completes the equipment to be .located at the central depot. Of course, it is entirely conceivable that this depot would be a small plant that would regenerate the charge from one railway car at a time and discharge the reclaimed refrigerant into the same or the ;next car which would make unnecessary the storage tanks referred to above. The description will now proceed to the equip-'- ment for the railway car. Referring to Figs..2,'

3 and 4, the body of a railway car is diagram- .matically. indicated at 6 I as having a separate is the desired temperature.

compartment 61 ateilther or both ends-of: the railway .car' 181.. The. compartment 82 contains a pairof tanks 63 which are intended to be at; the central depot. with weak. 'liquonthrough theoonnection Gt that is controlled'by the.- shut:- ofi valve 55 tanks 63 are interconnected. by a plurality of cross pipes .661 It will be noted that tanksulii! are: provided with finned: surfaces indicated at: 5.1 :mclmthat: the connecting pipes 66.- are provided with finned. surfaces '68 which assist in; the. air cooling. of the tanks and connecting pipes; Whether the compartment Elisa. closed-off. space on the inside of the body-of the can or a separate compartment outside of the of. the .car as indicated at 6.2 is immaw terial. For. the purposes or securing air circulati'on theaend wa-ll' as is provided with 1 t through passes: into; the compartment: 62:. Outlets. or ventilatorsfor-"the air are indicated at. H, .eachihaving a forward and rear opening covered: .by pivoted" leaves or flaps 13 that close under the pressureof the air from" thefdirect'ron oftravel but are-free toop'en in the opposite. or rear direction to allow the escape air from. the compartment: 62'. I

:Mmmted: on; the interior of" the car are arpa'i r.

01$? 16. of smaller capacity than the tanks 63, the; tanks being: vertically disposed inrtherrerspective corners of the car so as to occupy the least amount of useful load carrying space: and? being adaptedito contain the refrigerant used.

A number of different arrangements may be" provided for cooling the interior of the Onesuch arrangement is: shown in. Figs. 2",. 3

and? 41 wdlerein the tanks I516 are: interconnected. by means of a, series of horizontally extending:

pipes 11 that are provided with filmed cooling.

suriaces 12%. The tanks 1.6. are contained: in. a.

zauzw temyto escape thrwghthepipe: 88 into the abscrber' system of tankstfiand pipes 59.

circulate; through the: openings 8.0 into the com- I partment containing the tanks 16 and associated:v

pipes, upwardly thereover, and thence out into thezca-r;

The tanks 78 are central depot with preacooled.

intended in be: filled. at the;

valve 82;

Regulation of' the temperature of. the. car is.

llhe 81 carried by pIu-nger BB- against. which spring" 85 presses, the tension of the spring being ads.

justable by means of the screw 88: 1

The temperature maintained in the car is -directly proportional to thepressure existingi the tanks "5 and cooling pipes T1 It will: he. assumed that a fifteen pound 'pressurewill' main.-

tain' a zero temperature in the car-and that this ratus will continue to functionand ex.-

ing surtaces ll, 18. When the pressure-in: the

accumulated vapor and gas in the cooliue sy refrigerant through the: connection controlled by-sha The cooling appard =70 tracted from the air circulating 'over the 8001i thepressure-hasbeerr lowered to-fi'fiteen pounds; the valve disk closes under the action of the and thus the temperature of the car is maintained-at afinedlevel.

The-i unoti'oning oi the apparatus on the railway car may be described as follows: With the :63 and'lirfi l ledi respectively with pro-cooled weak liouor and' pie-cooled rer'rigerant, the i e-- trigemntfbegins to boil off of the body in the tanks '1 i and-i throughsthe cooling coilsin. accordance with the requirements toreaeh main-- tain the desired temperature in the car; The spent gias' leaves the: cooling coils and escapes into the weak: liquor or absorber tanks 63* where it. is absorbed? and retained: until the liquor is drawmofi atthecentral depot other: words, the only portions of the absorption-cycle that are accomplished on therail was! caraa'eexpansionor evaporation and absorption-'-only whatisnecessary in. the step of cool"- ing; All: the other: steps oi the refrigerating cycle'are performed at some other point. The resultant advantages in thev operation? 01: a plurality of. refrigerated railwaycars are-obvious.

When the railway car reaches the central depot the flexible hose I381 is connected .t'olthe; outlet connection 64 m: the tank's 63, any well-known. form. of leak-proof connecting nozzlebeing. used for this purpose- There. may-or may not be; a

pump; inserted in this line; depending upon the relative heights of the rai lmasccarwand: central plant. or :of. the" relative: pressures; between the tanks 63 on railway and the tank M in:- the central depot. It. may be explained atthis point that during the course of the: run of the railway car what was weak-I liquor in. the f at the beginning ofi theirun' has nowv become strong'liquor by reasonoi the-absorption. of the. spent gases: from. the cooling. coils. This now'strong. liquor is transferred to the storage; tank. ll after the. valves 55 and I102 are: opened;

At. the same-time the flexible-hose |(l-3. is2con.- nected' to: the outlet connection 8|? on the tanks. 16 the same manner-rot cozmection: being effected; Alsoa pump may or may not be:included inrthis connection. line; Ehen' uponi opening: the valves. 82 and: 1M. and: one or: the other of the. valves :105 and I05 the unspent charge of liquid ammonia or refrigerant, it any; in the tanks. 1:6 is drawn ofi' therailway car and stored; one or the other ofv theastorage tanks 32, 331..

The: railway car is then ready to be re-filled; so as. to .continue' its run. This is done by detaching the hoseconnecti'on- PM from the: outlet connection 64* and attaching thereto the flexible .hose. connection HIT leading. from the weak liquor storage tank 39; Thisconnect'ion line may' or may not include a pump. Upon opening the valve- Hill! the tanks 63' are filled. with pro-cooled weak liquor from. the storage tank". 39. When the. desired charge has been. put; into: the. tanks. 63, the valves 55 and I08 are shut pit and the flexible hose. .connectionz Hl l detached. The flexible: hoseconnection Hl3= remains connected to outlet Hi, andlif the valve. N15 has been opened when the unspent-charge has beentaken fromzth'e railway? car. it is' now clbsed and valve Illli is openedi. The pump, if: used; is reversed: and the preecooledt charge in. the storage: tank 32 is' insertedz into thestorage: tanks 1-6 on the railwayrcar... Assoomas the requireducharge has beentmade, valves 82,. llfld'vandl I06 areclosed; the flexihleahose: connection. l I13: is-v detached railw ay car is now ready to continue its run with a' fresh charge of cooling agents.

A modified arrangement of cooling surfaces is shown in Fig. 6. In this figure, one or more tanks 9I are intended to hold the charge of precooled refrigerant corresponding to the tanks I6 of Fig. 2,-and one or more tanks 92 are intended to hold the charge of weak liquor, the same as tanks 63 of Fig. "2. In this figure, the cooling surfaces are provided by a set of roof coils 93 and one or more side wall coils 94. The roof coils are separated'lna separate compartment by the partltion wall 95. The coils 93 and 94 may be interconnected or may be independently supplied with refrigerant from the tanks 9| but in this figure they are intended to be shown interconnected, and fed from the supply pipe 96 having expansion valve 91 therein. The supply pipe 96 is not shown connected to the coils 93 and 94 because they are broken away. The point of connection is at a distance removed from the absorber tanks 92. The expanded refrigerant passes through the coils 99,- 94, is vaporized in absorbing the heat from the interior of the car and passes out of the coils through the return line indicated at 98 and which extends-into the absorber tanks 92. If desired, the top of the tanks 9| may be vented to the return line through the valved connection 99 as shown.

Otherwise, the car portion of the entire refrigeration system is charged, emptied, and functions as described above in connection with Figs. 2, 3 and 4.

A further modified system and arrangement of cooling tanks is shown in Fig, 7. In this figure, the railway car is diagrammatically illustrated at III. Mounted inside of the car and in one end thereof is one or more tanks II2 intended to be filled with pre-cooled liquid ammonia through the connection H3 controlled by the valve I H. The tank I I2is in communicated with the coils of an air cooling unit H5 through the valve H6 and associated piping. This latter unit may be of any well known construction, that shown in the drawing being for purposes of illustration only. The return line for the gases spent in the air cooling unit is indicated at II I, this pipe extending down the end wall of the ,car and along the bottom into communication with one or more tanks H8 and H9 respectively arranged longitudinally and transversely of the railway car. These tanks are provided with finned cooling surfaces as indicated at I20 and are the weak liquor storage or absorber tanks equivalent to the tanks 63 of Figs. 2 to 4. Theyare intended to be filled with weak liquor through the valved connections I22. It will be noted that the tanks I I8 and I I9 are disposed underneath the car body I I I. The tanks ma or ma not be provided with a plurality of internal splash guard plates III), which are perforated for uid therethrough.

The bunker wall or partition I23 divides the cooling equipment off from the remainder of the car interior. However, the bunker wall I23 does not extend entirely to the bottom or to the top of the car, allowing for the circulation of air thereabout. Mounted within the air cooling unit H5 is a fan I24, the prime mover of which is indicated at I25. The prime mover in this case may be an electric motor or may be, as indicated, an air motor connected to the compressed air lines of the train through the pipes I26 and I21.

When the tanks H8, H9 and H2 are filled as heretofore described at the central depot, and the the passage of the liq-' fan I24 operates it circulates the air through the body of the car, through the compartment in back of the bunker wall I23 and through the air cooling unit H5, where the air is cooled. This circulation of cold air serves to refrigerate the interior of the car III. The circulation of warm air past the unit H5 vaporizes the refrigerant, the spent gases leaving the radiator of the air cooling unit H5 and becoming absorbed in the liquor in the tanks H8, H9. When the car returns to the central depot the tanks H4, H8 and I I9 are emptied and may be refilled as described above. j

It will be apparent from the foregoing description that a system of mobile'refrigeration has been provided, which involves no moving parts and a minimum of apparatus on the mobile unit together with a new and improved system of handling a plurality of such mobile units; Furthermore, the system of charging and regulating the temperature of the railway car is simple and efficient. I

Modifications may be made in the arrangement and location of parts within the spirit and scope of the invention, and such modifications are intended to be covered by the. appended claims,

What is claimed is:

l. A refrigerated power-moved unit comprising a bod having cooling apparatus therefor comprising onl an evaporator of an absorption refrigeration system mounted in the body and arranged to cool the interior. thereof, the evaporator comprising two spaced-apart refrigerant holding tanks, a plurality of pipes each interconnecting said tanks and provided with finned cooling surfaces, anabsorber carried by said body and connected to the evaporator, and means for I air cooling the absorber.

2. A refrigerator power-moved unit comprising a body, a combined refrigerant holder and evaporator of an absorption refrigeration system mounted in the body and having refrigerant storage capacity, an absorber for the spent refrigerant mounted outside said body, a pipe connection from the evaporator to the absorber, and means in said connection responsive to the pressure in said evaporator for automatically limiting the evaporator pressure to maintain substantially uniform temperature in the evaporator.

'3. A refrigerated unit comprising a body, a combined refrigerant holder and evaporator of an absorption refrigeration system mounted in the body and having refrigerant storage capacity, an absorber for the spent refrigerant mounted outside said body, a pipe connection from the evaporator to the absorber, and a regulator valve mounted in said pipe connection, said regulator valve being responsive to the pressure in said evaporator for automatically limiting the evaporator pressure to maintain substantially uniform temperature in the evaporator.

4. A refrigerated mobile transportation unit comprising a body having cooling apparatus therefor including an evaporator of an absorption refrigeration system mounted in the body and arranged to cool the interior thereof, the evaporator comprising two spaced-apart refrigerant holders, a plurality of pipes each interconnecting said holders and'having extensive cooling surfaces, an absorber carried by said body in such position that air passes thereover upon movement of the unit, connections between said absorber and said holders, and means whereby the refrigerant .holders and absorber may be periodically supol elwithfreshre ie rantand absorbe r sp tivelyb A l if gera ed mobile transpo tation un oomprisihg a body having. cooling. apparatus therefor inelucfing evaporator of an absorbent refrigeration system mounted. in the body and arranged to .cool the interior thereof, the evapo- .rator vcomprisi'ng twoparallel spaced apart re.- Irieem t holders interconnect d y a plurality of Parallel pipesearranged at right angles to the holder axes'in spaced relation axially of said tanks andhavine extensive ooo ine urfa s, on absorber carried by said body, and connections between sa-idabsorber and said holders. 1

.6. A refi'igerated mobile transportation unit comprising a body' having .cooling apparatus therefor including an evaporator of an absorbent refrigeration system mounted in the body and an. absorber connected to said coils and mounted exteriorly' ofv said in such. position that air passes i'ire lv ther over up n. mov n of h unit mean resp nsive o th p s in sai evaporator for au matically limitin the vapo rator pressu e to maintain substantially ni rm tempe ature in the .evaporatonand means whereby the. evaporator and absorber may be periodically supplied with fresh refrigerant and ab.- sorbent resn eti e v.

.8 A refrigerated mobile. unit comprising an enolfosure. an evaporatoracarried by said unitaaozs w thin s id en o ure, arfirieerantstorage-tank, means connecting said tank 110: issues/aerator andinol ine means t r regulat ng. the-flow of refri e ant from aid tank to saiclle-v s or on an absorber connected to said evaporator and mounted exteriorly of said enclosure in such position that air passes freely thereover movement of the unit, and means whereby tank and absorber may be periodically supplied. fresh refrigerant and absorbent respectively. a

.9. ,In a mobile transportation nnit,,.. a bndy'oonam an a orp ive refriee a ionsvs em evaporator oompris-ing two spaeed apart retrigeram holding tank a p urality f pin seaoh-intet onnecting said holder tanks and provided finned cooling surfaces, an absorber connected to said evaporator, and means for directing .eooling fluid into contact with said absorber.

10. In a mobile transportation unit a body eon.- .taining a combined storage tank and evaporator of an absorptive. refrigeration system having re.- frigerant storage capacity, an absorber for spent refrigerant, a pipe interconnecting said evapm rator and absorber, and means responsive to the pressure in said evap rator for automatically lime iting the evap rator pressure to maint in s bstantially uniform temperature the evaporator.

11. Ina mobile transportation unit, abodyeom taining a refrigerant holding tank, an evaporator coil eonnectedto said tankr an absorber forspent refrigerant outside said a pipe ,eonnecting said. evaporator coil and, absorber, andiare ulator valve mounted in said pipe, said valve being responfiive. to the pressure in said evaporator ,ooil for, automatioally limiting the evaporator coil pressure to maintain substantially uniform tema perature in the evaporator. coil. v

STANDARD GAP 8: SEAL CORRORAITION, Assignee of Oliver 0. Irwin, Deceased. By RUSSEL MCGEE, v 1 President.

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