US2410334A

US2410334A - Refrigeration

Info

Publication number: US2410334A
Application number: US419815A
Authority: US
Inventors: George A Brace
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1941-11-21
Filing date: 1941-11-21
Publication date: 1946-10-29
Anticipated expiration: 1963-10-29

Description

G. A. BRACE REFRIGERATION Oct: 29, 1946.

' 5-Sheets-Sheet 1 .Filed Nov. 21, 1941 g}. is.

v INVENTOR Geozyejhfiz'ace BY ,5} W

- ATTORNEY G.,A. BRACE Oct. 29, 1946.

REFRIGERATION Filed Nov. 21, 1941 3 Sheets-Sheet 2 INVENTOR Geo eAzBrace ATTORNEY 4%? g g? I s Sheets-Shet a INVENTOR I 6/ Geozye A. Brae;

Y ATTORNEY Patented Oct. 29, 1946 UNETED REFRIGERATION George A. Brace, Washington, D. C., assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application November 21, 1941, Serial No. 419,815

13 Claims.

This invention relates to certain novel constructions and arrangements. of refrigeration apparatus, and to improved methods of producing refrigeration.

While the invention, in certain of its aspects. is applicableto various types of refrigeration. systems such as the motor-compressor and the continuous absorption types, yet it has particular utility. when embodied in an intermittent type of system. This latter type, although having ad-.' vantages over other conventional systems, has certain disadvantages which have prevented it from enjoying popular acceptance. These defects have been overcome by this present invention.

For example, intermittent systems have not been suitable where continuous refrigerator is required or desirable. Furthermore, great difficulty has been experienced heretofore in controlling the production of refrigeration in these sys--. tems. While there have been various proposals to remedy these and other deficiencies, the sug gested constructions have been ineffective, compleX, and costly to construct and maintain. For

instance, in endeavoring to provide continuous refrigeration, it has been proposed to employ a variety of cold hold-over expedients such as eutectic arrangements, brine tanks, metallic accumulators, and other equally cumbersome andunsatis-- factory constructions. to utilizerthev cold storing capacity-of ice in conventional ice trays to provide refrigeration during the reversal of therefrigeration cycle. In addition; to being only partially effective, even when the trays remainfilled with ice, this latter practice entails themany well known disadvantages: attending the useofice trays.

According tothe present invention, a refrigera tionapparatus is provided having an exceedingly simple combined evaporator and cold accumulator which entirely eliminates the many disad vantages of prior constructions. More Sp cifically, a-plainwater receptacle is arranged in heat exchange. relation to. the space to be cooled and to an. evaporator, and preferably in such fashion that a plurality of pieces of ice will form on the inner wall of the receptacle while refrigerant is evaporating. and become freed for flotation in the water when. evaporation ceases. The pieces of ice and the large body of water thus coolednearly I to freezing temperature provide a refrigeration source ofconstant temperature and ample capac- W. t arry her i 'serati n. oad-u til e efrigerationcycle has reversedor a new, supply of. e ri rant has been. g ne a ed- It has also been proposed As will be manifest from the foregoing, the in- Vention has special applicability to domestic household refrigerators in- Which it is desired to maintain substantially uniform food storage temperatures, a high relativehumidity and a readily available supply of ice in small pieces. In such an application of the invention, the water receptacle replaces the conventional sharp freezing chamber and ice trays. In addition to serving as an ice maker and cold water storage vessel, this arrangement functions as a thermal flywheel capable of maintaining uniform temperature conditions in the food compartment at all times, and particularly during that portion of the being produced in the evaporator proper.

It will also be appreciatedthat very little frosting of the evaporator will occur since the large body of Water constitutes the principal load. Moreover, the arrangement is automatically selfdefrosting at the end of each evaporation period. Frosting can be, eliminated if the evaporator proper is heat insulated except for those areas in contact with the water receptacle.

As will be obvious from the, foregoing, the principles of this invention are applicable either to a single or a multiple unit intermittent absorptionsystem, it being understood that a multiple unit comprises two or more similar units arranged to refrigerate the. same space but so controlled as to operate out of phase with one another.

It is accordingly anobject of the invention. to provide a new method of refrigerating a space in which evaporation of the primary refrigerant or working medium takes place in a non-con.- tinuous manner. Morespecifically, an object of the invention is to providefor the continuous refrigeration of a space by evaporating a refrigerant medium periodically to congeal a portion of a body of water and utilizing the cold thus accumulated to maintain a desired temperature until the resumption of evaporation of refrigerant from a single or a multiple source.

Another object of the invention is to provide a refrigeration system having a novel evaporator, ice-maker, and cold' hold-over construction. More particularly, it is an; object of the invention to provide a domestic type refrigerator operating discontinuously but capable of maintaining substantially uniform temperatures and a high. relative humidity in the storage compartment thereof.

It isa further object of the invention tome-- refrigeration. cycle in which no refrigeration is irrespective of Whether the refrigerant is derived Another object is the provision of a simpleand effective mode of controlling the production of refrigeration by either a single .or multiple unit intermittent absorption system.

It is a further object of the invention to provide a novel system for making and harvesting pieces of ice automatically and independently of control devices responsive to a condition of the evaporator, and independently of control devices within the refrigeration apparatus proper. 7

Other objects and advantages of this invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which: 7

Figure l is a diagrammatic representation of the refrigerating apparatus and control therefor according to this invention;

Figures 2 and 3 are detailed views of one of the generator-absorbers of Figure 1;

Figure 4 depicts the refrigerating apparatus of Figure 1 in assembled relationship with a domestic refrigerator cabinet;

Figure 5 is a detailed View of the evaporator with the combined ice freezing, humidifying, cold water storage tank and cold accumulator supported on the evaporator;

Figure 6 shows an arrangement in which the invention is applied t0 a single refrigerating unit; and

Figure 7 shows a modified form of evaporator and water tank according to this invention.

Referringto the drawings, A, A represent two generator-absorbers, C, C two primary condensers and E, E two evaporators. The generator-absorbers A, A are connected by conduits l9, It! to the condensers C, C'. The condensers C, C have a downwardly inclined slope throughout and are connected by conduits l2, 2 to receiving vessels l4, [4 which form a part of the evaporators E, E.

Each generator-absorber comprises an outer cylindrical wall 15, an intermediate cylindrical wall 18 and an inner cylindrical wall 28. The outer wall !6 and the intermediate wall is are connected at the ends by end walls 22 to form a closed annular space which is divided into a plurality of chambers by plates 24 which may be welded to both the outer. wall it and the intermediate wall l8. Each of the plates 24 has a plurality of openings 25 therein. Afunnel-like member 28 is fitted into one set of the openings 26 and is positioned immediately below the vapor tube Ill. The chambers formed by the plates 24 are suitably charged with a solid absorbent such as strontium chloride (SlClz) The inner Wall 20 and the intermediate wall l8 extend beyond the ends of the outer wall 16 and are joined by end members 30. The space between the inner wall 20 and the intermediate wall lil forms cooling chambers or heat exchange devices of indirect cooling circuits for the genera ator-absorbers A and A. The space between the intermediate wall l8 and the inner wall 28 is preferably provided with a plurality of radial ribs (not shown) for the purpose of providing? for the better transfer of heat from the electrical heating element 32, which is positioned in the interior of the inner wall 28 to the solid absorbent in the generator-absorber proper.

The upper end of the space between the walls- IS and 20 is connected by conduits 34, 3G to the secondary condensers 36, 3'5. The

secondary condensers

36, 38 have a continuous downward slope throughout and lead to a reservoir 38. The

reservoir 38 is connected by conduit 49 to a valve l4, l4 above the point of connection of the conduits 5B, 50'. The sinuous portions 52, 52' are arranged closer together at the bottom so as to form a sort of V-formation as viewed in Figure 5.

A water tank 54 of similar cross-sectional shape is supported on the V-shaped formation. The

sinuous portions

52, 52 of the evaporators E, E have a plurality of heat conducting pads 55 bonded thereto so as to form a good thermal path between the tank 54 and the evaporator coil at a plurality of isolated points, leaving the re vmainder of the walls of the tank insulated from r the evaporator coils by an air space.

Thermostatic bulbs 56, 58' contact the outer surfaces of generator-absorbers A, A and are connected by

capillary tubes

58, 58 to bellows 69,

60' which upon expansion and contraction are:

adapted to operate the snap acting device 138., The bulbs 56, 5'", tubes 53, 58 and bellows 6Q, 60 are filled with a suitable vaporizable fluid so that the

bellows

60, 68 will expand and contract upon variation in temperature of the

bulbs

56, 56 as is well known in the art. 62 is positioned to be actuated by the snap acting device 48.

A thermostatic bulb 64 is positioned adjacent the evaporators E, E when the apparatus is positioned in a refrigerator cabinet as will be later described and is responsive to the temperature of the air in the interior of the cabinet. The bulb 64 is connected by a capillary tube 66 to a bellows 68. The bulb 64, tube 66 and bellow 68 are filled with suitable vaporizable fluid so that the bellows 68 will expand and contract upon Variation in temperature of the air in the cabinet, as is well known in the art. Upon expansion and contraction the bellows 68 is adapted to actuate, a snap acting device 70 which in turn operates:v the valve 12 in the conduit 40 and an electric; switch 14.

One side of the power line is connected to one side of the switch 74. The other side of the switch 74 is connected by suitable conductors as;

shown to two of the contacts of the switch 62. The other two contacts of the switch 62 are con nected by suitable conductors to one side of the heating elements 32, 32', the other side of which is connected to the other side of the power line.

The generator-absorbers A, A are charged with a suitable solid absorbent such as strontium chloride and a'refrigerant such as ammonia as is well known in the art. When strontium chloride absorbs ammonia, addition compounds, such A snap acting switch I as SrClalNI-Is, SrClaZNHa, lSrChA-NHa, and SrClaBNI-Is are formed. As theaddition compounds are formed the strontium chloride expands'and when 8 molecules of ammonia :have been absorbed, it willoccupy a volume approximately 2 /2 times its original volume. Preferably, suflicient strontium chloride is charged-into the generator-absorbers that the walls thereof will remain under pressure due to the expanded strontium'chlorideeven atthe end of a generating phase -of a particular generator-absorber. When a generator-absorberis fully=charged with ammonia, its walls will of course be under .a greater pressure due to thee-xpanded absorbent.

The-indirect cooling circuit for the-generator..- absorbers A, A is suitably charged with .a'vaporizable liquid such as methyl chloride. The pressure-within the indirect cooling-circuit .isnot high so thatthe snap acting device 48 may beled into the interior-of the valve chamber A2 .througha suitable fiexiblejoint 16.

The refrigerating apparatus just described and shown diagrammatically in Figure .1.is adapted to be arranged so as to be mounted in a domestic refrigerator cabinet as-shown in Figures 4 and .5. The cabinet comprises a black insulated wall 89, lower insulated wall 82, frontaccess door 84 and top access door 86. At the rearofthe cabinet is provided'a fiue 83for the circulation of air over the heat rejecting parts of the apparatus. .An opening 9!] at the bottom of the flue .88 provides for theentranceotcooling air and a screen 92 provides .for its .exit. The generator-absorbers A, A areimbedded in insulation @1101! and .are arranged at the sides of the flue 88 so asnot to interfere .withthe air circulation. Theprimary condensersC, C extend .across'the -flue ,88 near its upper end and the secondary condensers 35, 3.6 are similarly arrangedbelow the primarycondensers.

The collecting :vessels L4, .l4'.,and.the.downwardly extending conduits .50 are imbedded in an insulatingenclosure l for an opening in the back of the cabinet. The evaporatorst-E, E are supported by suitable brackets .96. The tank 54 is adapted to be lifted bodily out of the cabinet through the access door-.86 and has a spigot 98 so that .water can be dispensedtherefrom. The entire operating parts ofthe'refrigerating apparatus including the evaporator'zand the closure194 are adapted to be removed bodily:from: the cabinet proper.

As shown in Figure 1 the vvalve-l2 isopen and the switch 14 is.closed. The-switch 62 is set so thatelectricity will be conducted'togthe heating element 32 of the generator-absprber A which will be heated. 'Thetbulbgfiil is contracted and the bulb 60' is expanded by a previous heating of the generator-absorber-A'as will be described hereinafter. be positioned to the left, t'he val-ve:-4 6will .be closed and the valve 46'open.

Withthe control set as in.Figure.l the heating of the generator-absorber A will drive-refrigerant vapor from the solid absorbent contained there- 4 in. The heat from theheating element 32 is transferred tothe solid absorbentin the generator-absorber A bythe ribs (not shown) inthe space between the walls I8 and andjby the partitions 24. This refrigerant Vapor will pass by the conduit lllto the condenser C where it will condense and the'heat of condensation will be carried away by air'fiowing over the heat rejecting. fins mounted on the tubes of the condenser. Upon condensing the'liquid refrigerant Thus :thesnap acting device-will will flow. downwardly through. the. tubes .Qf .;the condenser C into the receiving vessel L4 and f ll the tubes 5! and 52ofgthe eyaDoratOrE. Durin the generation ,of refrigerant in the generatorabsorber A some of the refrigerant NB DQ ma condense in the conduit Ill and, flow backwardly into the generatoreabsorber A. The funnel member 28 isprovided to pre l t .this qndensed refrigerant from contacting the solidv absorbent in the generator-absorbers. and deteriorating ;it. Instead the condensed refrigerantwill flow to the bottom of the generator-absorberandbe vaporized so as not to contact the solidabsorbentwhlle in liquid form.

During the heating of the generator-absorber A, the auxiliary cooling liquid in the space be". tween the

cylinders

18 and 20 of thegeneratorabsorber A will quickly vaporize andflow by oonduit 34 into the secondary condenser 36, air flowing over the fins of the condenser 363N111 carry away the heat of condensation of theauxiliary fluid whereby it will condense and flow downwardly through the tubes of the condenser 35 into the reservoir 38. This liquid auxiliary cooling fluid cannot return -to the generatorabsorber A at this time because. the .yalve. 4fi is closed.

In the meantime absorption of refrigerant vapor is'taking place in the generator-absorber A in a manner which will be described in connection with the absorption which takes place in the generator-absorber vA when-the control .op-

erates to shift the generator-absorberAfrom the generating phase to the absorption phase and the generator-absorber A' from the absorption phase to the generating .phase.

When sufficient refrigerant is driven from the absorbent in the generator-absorber- -A, the generator-absorber A will quickly risein tempera ture. This rise in temperature will be quite abrupt even though the heat supplied to the generator-absorber A remains constant. This comes about by reason of the fact that while refrigerant is being driven from the solid absorbent the heat supplied thereto is being utilized to vaporize the refrigerant, but whenthe refrigerant is vaporized the heat supplied quickly raises the temperature of the generator absorber to a much higher value. v

This will cause the liquid in the bulb 5,8 to vaporize whereby the bellows .50 will be expanded. At this time the bellows 58' will be contracted because absorption is taking place in the generator-absorberA' and the'fluid in bulb 56 will be condensed. Expansion of the bellowstil will push the snap acting. device A3 to the right. .As the snap acting device 48 moves to the right, it will operate the switch 52 to de-energize the heating element 32 and to'energize the heating element 32'. At the same time it will operate to open the valve 45 and-to close-the valve 46.

The indirect cooling system ischarged with sufficient auxiliary cooling medium that the reservoir 38 will always contain liquid cooling medium. When the control operates to open the valve 66 the liquid in the reservoir 38 will be dumped into the space betweenithe walls -18 and 20 of the generator-absorber A. Since'the generator-absorber A is hot at this time the auxiliary cooling liquid will be quickly .vaporizedby the transfer of .heat .of vaporization of the auxiliary liquid from the generator-absorber A and the generator-absorber A will be-quickly cooled. The cooling ofthegenerator absorber A will reduce the vapor-pressure-thereinand the The phase.

solid absorbent will begin to absorb refrigerant vapor and vaporization of the liquid refrigerant in theevaporator E will begin.

When the evaporation of. the liquid refrigerant in the evaporator E begins, the vapor willreturn to the generator-absorber A by conduit l2, condenser C and conduit lll. At the end of the generating period of the generator-absorber A, there is liable to be some liquid refrigerant in the condenser C and the conduit Hi. This liquid refrigerant is liable to be carried back tofthe" generator-absorber A by the returning vapors: If this returning liquid refrigerant should contact the solid absorbent in the genorator-absorber A it would rapidly deteriorate the solid absorbent. However, the funnel member 28 is provided to catch this liquid refrigerant and leadit to the bottom of the generator-absorber A where itwill collect and be vaporized during the next succeeding generating period and will not contact the solid absorbent while in liquid form as previously described in connection with the vapor condensed in conduit it! during the generating absorption proceeds in the generator-absorber A the heat of absorption is transferred to the auxiliary cooling liquid in the space between the walls l8 and 20. This vaporizes the auxiliary liquid and this vapor flows to the secondary condenser 36 by conduit 34. Here the vapor is condensed and the heat of condensation carried away by air flowing over the heat rejecting fins of the condenser 36. The tubes of the condenser 36 have a continued downward slope and the liquid auxiliary cooling fluid returns to the reservoir 38 to be returned in due time to the space between walls l8 and for further cooling action.

Preferably, the space between the walls I8, and the radial ribs (not shown) may be very narrow and the

tubes

34, 34 of small diameter so that the vapor formed therein during the absorption process will form bubbles between slugs of liquid and positively circulate the liquid cooling fluid by vapor lift action to augment the cooling of the generator-absorber.

In the evaporator E, the tubes and the collecting .vessel M are insulated while the sinuous tube 52 is exposed to ambient air and is in contact with the tank 54. This will cause a rapid evaporation of liquid refrigerant in the sinuous tube 52 and practically no evaporation in the tube 50. This action together with the fact that the tube 52 enters the vessel [4 at'a point above the tube 50 will cause the liquid refrigerant to be circulated up through the tube 52 and downwardly through the tube 50. This circulation will continue until substantially all the liquid refrigerant in the evaporator E is evaporated. This circulation and the evaporation of the liquid refrigerant will cause the sinuous tube 52 and the pads 55 to become very cold. Where the pads 55 contact the walls of the tank 54 the heat from the water at'that point will be quickly trans-. ferred to the evaporating refrigerant in the tube 52 and blocks of ice wil be formed as shown in Figure 5.

An alternative method is to charge the units with sufiicient refrigerant that the

tubes

50 and 52 and 50, 52 will contain liquid refrigerant at the end of the evaporation phase. In that case hot liquid refrigerant would not be dumped directly into the tubes of the evaporator. However, the use of the tank 54 full of cold water and ice would still act as a thermal flywheel to maintain-the cabinet temperature comparatively 8 uniform even though the rate of evaporation decreases toward the end of an evaporation phase. Ice will automatically be frozen and melted loose as before and each evaporator will be .automatically defrosted without the necessity of a specialized control other than for the control of the energization of the apparatus itself.

Asthe evaporation and absorption is taking place in the evaporator E and the generatorabsorber, A, the generator-absorber A is being heated by heating element 32'. Vapor is being driven from the solid absorbent in the generator-absorber A, condensed in the condenser C and collected in the evaporator E, as previously described in connection, with the evolution of vapor from the generator-absorber A,

By the time that substantially all the liquid refrigerant in the evaporator E has evaporated the refrigerant vapor will be driven from the generator-absorber A. This will cause the medium in the bulb 56 to expand the bellows 60. The snap acting device 48 will be moved to the left as viewed in Figure 1 whereby the valve 46 will be closed, the valve 46 opened and the switch 62 operated to energize the heating element 32 and to de-energize the heating element 32'. This will cause vaporization to take place in the generator-absorber A and absorption'in the generator-absorber A which will proceed as 'previously described.

As the liquid refrigerant again collects'in the evaporator E, it will be comparatively Warm. The heat from the warm liquid refrigerant will be transferred through pads 55 to the walls of the tank 54 in contact therewith and the blocks of ice on the interior of the 'walls of the tank 54 at that point will be melted loose, whereby they will float to the surface of the water in the tank 54 as shown in Figure 5. Ice will be frozen to and melted loose from the walls in the tank 54 where they are in contact with the pads 55 of the evaporator E, the same as described in connection with the evaporator E. The evaporators will be automatically defrosted periodically as the control shifts each unit to the generatin phase and the-tank 54 full of ice and cold water will act asla thermal fly-wheel'to maintain the temperature of the cabinet substantially uni- 50 form. In connection with'the automatic defrosting of theeVaporators, a drip tray is preferably provided beneath the evaporators for catching the condensed moisture and leading it to any suitable place of disposal.

As previously stated, the two units may be charged with suiiicient refrigerant so that the evaporators are never entirely empty and the vessels l4, M will also contain some liquid refrigerant at the end of the evaporation period. 60 In that case the ice blocks formed by a particular unit will melt loose more slowly during the generating period of that unit, the evaporator will be automatically defrosted and the tank 54 65 full of cold'water and ice will act as a thermal fly-wheel as before.

The control will operate to operate alternately the generator-absorbers A, A on a generating period and an absorption period as just described until the temperature of the air in the storage space goes below a predetermined limit. Atthat time the bulb 64 will operate to collapse the bellows B8 and operate to-close the valve 12 and open the switch 14. This will operate todeenergize the generator-absorber which is then '12. .in the generator-absorber being cooled ceases, no more liquid refrigerant will evaporate in the being energized and-to stop the flow o f coolin liquid inthe indirectcoolingncircuit.

The liquid cooling medium in the space be tween the walls l3 and 20 of the generator-absorber which is operatingon the absonption cycle will soon vaporize due to the-heat ofabsorption and will pass through the secondary condenser where it will be condensed. Since the tubesof the secondary condenser slope toward the reservoirts, this condensed liquidcannotreturn to -the cooling space-oi the generator-absorberbeing -cooled but will flow to the reservoir .Biiand be trapped out of the circuit by theclosed valve When the absorption of a refrigerant vapor evaporator. Thereafter the temperature of the air in the storage space will slowly rise .until'the control bellows 68 again acts to open the valve 12 and close switch I l. The two units will then.

. but when the switch M 'operatesto de-energize both units, evaporation will continue-in the-unit which is operating nthe absorption-evaporation phase until all of the refrigerant iniits evaporator is evaporateddue to the fact that circulation of the indirect coolingmediumwillcontinue as before until the generator-absorberionthe absorbing phase is fully charged with refrigerant.

It is Within the purview of this inventionto use the tank 54 in connection-with a singlev intermittently operating absorption unit of thegeneral type disclosed in connection with Figures 1 and 2. Thus the proper-humidity andtemperature in the cabinet can be maintained, ice will be automatically frozenand melted loose a-ndthe evaporator automatically defrosted by the use of a single unit and the thermal fly-wheel effect of the tank 54 filled with cold water and ice, utilized to its fullest-extent. Figure'fi shows such a modification.

The same reference characters will be applied to Figure 6 as applied to Figures 1'- and 2 insofar as they apply, The generator-absorber .A is charged with strontium chloride as the absorbent and ammonia as the refrigerant and theindirect cooling system is charged with methyl chloride as in the modification of Figure '1. The .-bellows B is connected to the snap acting'device 48 by a lost motion connection and the switch 62 is modified in that it has only two contacts. One contact of the switch is connectedto oneside. of a power line and the otherto one sideoi the heating element32. The otherside ofthe heating element 32 is connected to the other side of the power line. One of .the valves'in the valve chamber 42 as shown in Figure 1 is omitted'leaving only the valve which controls the opening to conduit 44.

The snap acting device 48 and the bellows 68' are so adjusted that the snap acting device 48 will besnapped to the'position shown innFigure 6 by the high temperature resulting'atthe end of the generating phase of the generatoreabsorber A as described in connection'with Figure 1 but will not besnapped to the reverse positionnuntil the bulb 56 has reached the highestzroomtemperature likely to be encountered fora pur oseito be later described.

In Figure 6 thetwo evaporators shown in Fig- -;ures 1 and have been combined into a single evaporator so that=it will support the water tank in a, manner similars'tojthat shownin Figure 5.

In .thiscase the evaporator-will havetwoconduits ,5!) and twoconduits .52 in thermal contact with the water tank- As shown in Figure 6 the bellows. 69 isexpanded and the snap acting device iflispositioned to the right sothatthevalve inuthe chamberrm is openas ,isthe snap acting switch62.

The generator-absorber. A will be on theabsorption phase and the cooling fluid will .be evaporatedjin the cooling pocket. of the generatorabsorberA bythe heat of. absorption. ,The vapor of the-coolingmedium willpass by conduit to the secondary condensertfiv where it ,will vvbe condensedand flow to therreceiverfifi. Fromthe receiver. the liqu dcoohng. medium will flow by nduit .46, val echam rdl and c nduit. 44

back tothe cooling jacket of the generator=absorber Aror further coolingof the generatorabsorber.

The absorption of ammonia in the generatorabsorber A causes a decrease inthe vapor pressure of the ammonia .in the evaporator. so that the liquid ammonia therein will evaporate to produce refrigeration in the manner. described in connectionwith Figure ,1. When all of therefrigerant in the evaporator is evaporatedabsorption will ceaseinthe generator -absorber A with theresult thatnomoreheat will be generated therein and itstemperature will be lowered to substantially room temperature by'the' circulatingcooling medium. This will cause the fluid in the bulb 56 to'contract sufficiently to collapse the bellows 60 and toshift thesnap acting device l- S to the left. 7

The Valve in the chamberAZ will be closed so that the cooling medium cannot flow to the gentional, control.

erator-absorber A through the conduit i i and the switch 52 will be closedso as toenergize the heating element 32. The fluid in; the cooling pocket of the generator-absorber A will be quickly vaporized therein by the heat supplied by-the heating element 32, will pass to the condenser 36 where it is liquefied and flow to the receiver 38 where it is trapped out of the cooling pocket of the generator-absorber A as described in connection with Figure 1.

Refrigerant vapor will be driven from the solid absorbent in the generator-absorber A, will pass to the condenser C where it is liquefied andiiow into the receiver l4 and the tubes 5%} and52 of the evaporator. This comparatively warm liquid refrigerant will'melt ice loose from the tank 5t as described in connection with Figure 1. At the same time the frost previously frozen to the evaporator will'be melted. The large body of cold water in the tank .Mtogether with the melting ice will provide athermalfiwwheelso that-the 'at a substantially constant temperature and humidity.

When the solid absorbent: in the generatorabsorber A has beenzsubstantially freed of ammonia, the temperature of the generator-absorber Awill quickly rise and expand the bellows Gfi sufficiently to move-the snap acting devicei8 back to the position show-n inFigure 6 whereby the absorption-evaporation. willbegin as. .previously explained. 1

Thegenerator-absorber will thus automatically operate alternately on the absorption and enerating phase as the temperature thereof rises-and falls without the necessity of providing any addi- Preferably, however, a. control similar to the. switch 1,4, valve. 12,,snap actin detrol other than that for the operation of the apvice 1 8, bellows and "bulbffid ishown and scribed in connectionwithjh'igure 1 is also provided so that the machine will cease to operate when the temperature of the air in the cabinet is reduced suifioiently; g 1 Figure 7 shows a modified evaporator and water tank in which'the evaporatorflcoils H are completely insulated from the air in the cabinet so that there is no danger of frost forming on the, ,1

I evaporator coils. In this modification the interior" l0 body of water and ice in the water tank.

In this modification the coils are arranged in the form of an inverted V and the tank H2 has a similarly shaped depression in its bottom so that it may be properly supported by the coil Hi and the walls of the depression will be in thermal contact with the coils l lfl. Preferably, heat conducting padstmay be. bonded to the coils H9 as in the modification shown. in Figure 5. The coils I I0 are insulated from the cabinet air by insulating material H4.

This modified evaporator may be used with a dual system such as shown in Figures 1 and 5 or g with a single system such as shown in Figure 6.

A reservoir vand downwardly extending conduit similar to the reservoir '14 and conduit/50 of Figure 6 have not been shown but are positioned to the rear of the tank H2 as viewed in Figure '7.

The use of the water tank 54 in the food storage space, whether it be used with a single or dual unit. maintains the humidity of the storage space at its proper value so that food stuffs stored therein will not be dehydrated and at the same time provides an ample supply of cold water for drinking purposes. g H

The alternate freezing and melting loose of the ice blocks insures an adequate supply of ice for use as desired without the necessity ofany conparatus itself. l

The large body of cold water with the ice floating thereon acts as a cold accumulator or thermal fly-wheel to maintain the food storage space at an even temperature in spite of the fact that warm liquid refrigerant is periodically introduced into the evaporators or the evaoorators are allowed to rise in temperature during the genera"- ing phase at the same time the evaporator: or evaporators are automatically defrosted without any special control for that purpose but by the normal cycling of the apparatus. V

The provision ofHa-bulb 64 and its associated control element insures that the temperature of the food storage compartment will not go to too low a value even though a cooling cycleis not completed at the time the temperature of the storage compartment reaches a proper low limit.

While I have shown but a'number of embodiments of myinvention it is to be understood that these embodiments are to be taken as illustrative only and not in a limiting sense. I do not wish to be limited to the particular structure shown and described but to include all equivalent variations thereof except as limited by the scope of the claims.

I claim: I

1. An absorption refrigerating apparatus comprising, a cabinet, two intermittently operating absorption refrigerating units assembled with said 7 cabinet; each unit comprising a generator-ab- 'evaporators being positioned on the interior of said cabinet; and an open combined ice freezer,

temperature and humidity stabilizing water tank in thermal contact with the evaporator of one of said units; said tank being of large capacity, in open communication with the interior of said cabinet and exposed to air circulating within said cabinet; the arrangement being such that ice is frozen to the Walls of said tank below the water level therein by the evaporation of refrigerant during the absorption-evaporation period of operation of said one unit and melted loose therefrom to float to the surface of the water in said tank by Warm liquid refrigerant introduced into said evaporator during the generation-condensation period of operation of said one unit.

2. An absorption refrigerator comprising a cabinet, said cabinet comprising a food compartment and an air flue extending upwardly along one side of said food compartment; an absorption refrigerating apparatus assembled with said cabinet comprising two intermittently and alternately operating absorption refrigerating units; each unit comprising a generator-absorber, a primary condenser and an evaporator connected by conduits to form a closed system; means arranged in operative relation to each of said evaporators whereby blocks of ice are being formed by one of said evaporators while blocksof ice previously formed by the other evaporator are being freed, an indirect cooling circuit for each genorator-absorber comprising a heat exchange device associated with each generator-absorber and a secondary condenser connected to said heat exchange device to form a closed circuit, said primary and secondary condensers being positioned in said air flue one above the other and .said evaporators being positioned in said food compartment. v

3. In combination, two intermittently operating absorption refrigerating units, each having an independent evaporator, an open water tank supported by said evaporators in heat transfer relationship therewith at a plurality of areas, means for alternately heating the generator-absorber of each unit to evolve refrigerant vapor from the absorbent and supply said refrigerant in liquid state to the evaporator of each unit, and means for alternately'cooling the generator-absorber of each unit to reabsorb the refrigerant from the I evaporator of first one unit and then the other whereby the evaporator of each unit is alternately cooled below the freezing temperature of water and heated to a temperature above the melting temperature of ice and ice is alternately frozen to and melted from the Walls of the tank opposite said heat transfer areas.

4. An absorption refrigerating apparatus comprising, two independent intermittently operating absorption refrigerating units; each of said units comprising a generator-absorber, a condenser and an evaporator connected by conduits ,to form a closed refrigerating system; a water tank having portions in thermal contact with each of said evaporators at a plurality of spaced points below the water level therein and means for intermittently and alternately operating said units on the generating and absorption phases the arrangement being such that ice will be frozen to portions of said tank in contact with the evaporatorof one unit while it is being melted loose 13 from portionsof the tank in contact with the evaporator of the other unit. I 5. An intermittently operating absorption refrigerating apparatus comprising, a generatorabsorber, a condenser, an evaporator; conduit means connecting saidgenerator-absorber, condenser and evaporator to form a closed refrigcrating system; said system being charged with a refrigerant and an absorbent, a water tank having walls in thermal contact with said evaporator in a plurality of separated areas below the level of water therein, means for heating said generator-absorber to evolve refrigerant vapor from the absorbent for condensation and supply to said evaporator in liquid form during said heating period, and means to alternately cool said generator-absorber to reabsorb refrigerant vapor and cause evaporation of the liquid refrigerant in the evaporator to freeze portions of the water in said tank opposite said areas during the absorption phase, the arrangement being such that the frozen portions of water are melted free of the tank by the sensible heat of newly condensed refrigerant during the generating phase.

6. In the operation of an intermittent absorption refrigerating apparatus of the type in which two intermittently operating absorption refrigerating systems are alternately heated to evolve refrigerantvapor from the absorbent in the generator-absorbers and condense it in the condensers and the generator-absorbers are alternately cooled to reabsorb the refrigerant vapor evaporating in the evaporators, that improvement which comprises freezing ice to the walls of an ice tank below the surface of water in said tank .1

at a plurality of spaced points in thermal contact with the evaporator of one unit by the evaporation of refrigerant in the one evaporator while melting ice loose from the walls of the ice tank below the surface of water in said tank at a plurality of spaced points in thermal contact with the evaporator of the other unit by warm liquid refrigerant flowing thereto.

'7. An absorption refrigerating apparatus comprising a cabinet, two intermittently operating refrigerating units associated with said cabinet; each unit comprising a generator-absorber, a primary condenser, and an evaporator connected by conduits to form a closed refrigerating system;

an indirect cooling circuit for said generator-absorbers including secondary condensers, each evaporator being positioned. in said cabinet; a combined ice freezer, cabinet cooler and cold accumulator in thermal contact with said evaporators; means for heating said generator-absorbers, means for alternately shifting said heating means and cooling circuit from one generatorabsorber to the other and means responsive .to the temperature of said cabinet interior for rendering both said heating means and said cooling circuit inactive to heat or cool either generatorabsorber.

8. A refrigerating apparatus comprising, a cabinet, two intermittently operating absorption refrigerating units associated with said cabinet; each unit including a generator-absorber, a primary condenser and an evaporator connected by conduits to form a closed refrigerating system; said evaporators being positioned in said cabinet; a combined ice freezer, box-cooler, cold accumulator and cabinet humidifier in thermal contact with said evaporators, an indirect cooling circuit for said generator-absorbers; said circuit including a heat exchange device associated with each generator-absorber, two secondary condensers and a common portion: means for'heating said generator-absorbers, means for alternately rendering said heating means and circuit operative to heat one generator-absorber and to cool the other and means responsive to the temperature of said cabinet for controlling the flow of fluid through said common portion of said cooling circuit.

9. In combination, a plurality of independent evaporator vessels, a container for water having a plurality of areas in heat exchange relation with each of said evaporators, a first refrigerant condensing means operatively'associated with one of said evaporatoraa second refrigerant condensing means independent of said first supply means and operatively associated with another of said evaporators, and a common control means for said first andsecond refrigerant condensing means, said control being so constructed and arranged as to alternately supply liquid refrigerant to one of said evaporators while the supply is cut off from the other evaporator, the arrangement being such that the supply of liquid refrigerant to each evaporator melts ice blocks free from the walls of said container at said plurality of areas which had previously been frozen thereto during the period when the supply of liquid refrigerant thereto was cut off.

10. Refrigeration apparatus comprising means for receiving liquid refrigerant, an evaporator including a plurality of conduits having their opposite ends connected to said receiving means at vertically spaced apart points, said conduits each having a downwardly extending portion communicating with a lower portion of said receiving means and an upwardly extending portion communicating with a portion of said receiving means above said lower portion, the arrangement of said conduits being such that refrigerant vapor serves to circulate refrigerant liquid therethrough, a water receptacle, said receptacle having zones of contact with the upwardly extending portions of said conduits, and means for supplying liquid refrigerant to and withdrawing refrigerant vapor from said receiving means and said evaporator.

11. An absorption refrigerating apparatus comprising a cabinet having a food storage compartment, an apparatus compartment, in the form of a flue for the circulation of air, an absorption refrigerating system associated with said cabinet, said system comprising two intermittently operating absorption-refrigerating units; each unit comprising a generator-absorber, a condenser and an evaporator connected by conduits to form a closed circuit; said evaporato-rs being so constructed and arranged as to form supports, a water tank supported in thermal contact with said supports, a closed cooling system for each generator-absorber comprising a heat exchanger associated with each generator-absorber connected by a conduit to a secondary condenser, said apparatus being so associated with said cabinet that the primary condenser and secondary condenser are positioned in said flue and said evaporator positioned in said food storage compartment so as to be removable from the cabinet as a unit.

12. The method of making ice which comprises; absorbing a refrigerant in a body of absorbent to cause evaporation thereof while in heat exchange relation with one wall of a water tank at a plurality of spaced points below the water level in said tank to freeze blocks of ice to said one wall at said plurality of spaced points while driving refrigerant vapor from a second body of absorbent, condensing said vapor and leading the '15 jwarm condensateinto heat exchange relation with a second wall of said tank at a plurality of spaced points below the water level in said tank to free previously frozen blocks of ice from the second wall at said spaced points; driving the previously absorbed refrigerant vapor from said first body of absorbent, recondensing said vapor and leading the warm condensate again into heat exchange relation with said first wall at said spaced points to free the blocks of ice produced by the original evaporation of the refrigerant while reabsorbing refrigerant in said second body of absorbent to cause evaporation of the refrigerant in heat exchange relation with the second wall at said plurality of spaced points to freeze new blocks of ice to said second wall. at said spaced points and continuing the foregoing steps to alternately freeze ice to said first wall while freeing ice from said second wall and vice versa.

13. An absorption refrigerating apparatus comprising, two intermittently operating absorption refrigerating units each including a generatorabsorber, a condenser and an evaporator connected by conduits to form a closed system, said evaporators being spaced apart to form a pairof spaced supports and an open water tank supported between and in thermal contact with said supports.

GEO. A. BRACE.