US2138612A - Refrigerating apparatus - Google Patents

Description

Penman. 29, 1933 PATENT OFFICE H liJiJ RIl'z:HEATING APPARATUS Lawrence A. Philippi Detroit, Mich.,"assignor to Nash-Kelvinator Corpo'ratiom Detroit, Micln, acorporation of I Application July 2, 1937, Serial No. 151,571

1 Claim. (cite-125) This invention relates to refrigeration and more particularly to an improved method of and apparatus for refrigeration, Y

One of the objects of my invention is to provide an improved arrangement for conducting liquid refrigerant to a refrigerant evaporating zone located above the condensing zone and to provide an improved arrangement for controlling the flow of liquid refrigerant .to the evaporating zone.

Another object of my invention is to provide an improved method of refrigeration which consists in elevating liquid refrigerant to an evaporating zone which is located at a point above the condensing zone by utilizing the application of heat for conducting the liquid refrigerant and control-.- ling the flow of liquid refrigerant to the point of heat application in accordance with changes in pressures existing in the evaporating zone.

: Another object'of myinvention is to maintain a substantially constant temperature differential between primary and secondary refrigerating systems by controlling the pumping of liquid refrigerant to the evaporating zone of the secondary system in accordance with the changes in the environment 'air temperatures adjacent the refrigerant pumping device and by controlling the flow of liquid refrigerant to the refrigerant pumping device in accordance with changes in m pressures within the secondary refrigerating sys-' tem.

Other objects and advantages of the present invention will become apparent upon perusal of the following description, reference being had to 35 the accompanying drawings in which are illustrated preferred forms of my invention. 7

In the drawings:' Fig. lis a diagrammatic view of a refrigerating system including primary and secondary rem frigerating systems embodying features of my invention; r

Fig. 2 is a diagrammatic view of a modified form of secondary system;

Fig. 3 is a view in cross-section of a pressure 15 responsive valve embodying features of my invention; i

Fig. 4 is a diagrammatic view of another modified form of secondary refrigerating systems; and Fig. 5 is a diagrammatic view of a still further modified form ofsecondary system. V I

In some instances in the use of primary and secondary refrigerating systems itlias been found desirable to position the refrigerant evaporator of the secondary refrigerating system entirely 55 above the condensing element of the secondary -system. One example of this use is found in the refrigeration of motor' vehicles, such as trucks, wherein the refrigerant evaporating element is positioned adjacent the uppermost part of the compartment wherein foods are stored for deliv- 5 cry and the condenser is located in the lower portion of the vehicle body and cooled by ice or blocks of CQz. By this arrangement the ice or blocks of COzconstitute the primary refrigerat ing system and may be readily placed in contact with the condenser of the secondary system without, elevating such primary system to undue height to which the secondary refrigerant evaporator is located. in some installations it is found desirable to' associate with the secondary condenser a refrigerating system which is automatic and is of the so-called compression type. In either case wherein-the secondary condenser is located below the secondary evaporator some provisions m ust be made for pumping or otherwise conducting liquid refrigerant from the secondary condenser to the secondary evaporator. In many instances it has been found desirable to maintain the temperature of the secondary system evaporator considerably above the lowest temperatures prevailing in the primary system.

In accordance with my invention I provide an improved arrangement for conducting liquid re-- frigerant to a refrigerant evaporating element of a secondary-refrigerating system, which element is located above the condensing element of the system, andalso provide an improved arrangement for positively controlling the temperatures existing in the secondary system.

Referring to the drawings and particularly Fig. 1, the numeral 20 designates in general a com-- partment which is provided for the storage of foods and the like and may be the compartment of any suitable refrigerating apparatus such as meat.boxes,'household refrigerators, or cooling compartments of motor vehicles and the like. The compartment 20 is maintained at a substan-' tially constant temperature by means of a secondary refrigerating system 22 which includes a heat absorber -or refrigerant evaporating ele- 5 ment 24 disposed within the enclosure 20 and a heat dissipator or condenser 26 for dissipating; the heat absorbed in the element 24.- Liquid refrig'erant delivered from the condenser 25 to p the evaporator 24 by a liquid supply conduit 28.

The conduit 28 has an outlet 30 associated with a vessel 3| which is connected-in open communlcation with inlet 32 and outlet 33 of theevaporator 24. Gaseous refrigerant is conducted from the evaporator 24 to the condenser 26 through a por lift pump or trap 48 which is connected in the liquid supply line between the condenser 26 and the evaporator 24. This vapor lift pump or trap is formed in the general shape of a U havconduit 28. By this arrangement liquid .refriging both ends 4| and 42 connected to the supply erant leaving the condenser 26 will first pass into the leg 42 of trap 48 and by the application of heatto the trap 48 vaporization will take place to such an extent that it will lift liquid refrigerant upwardly through .the conduit 28 into the vessel 3| whence it passes into the inlet 32 of the evaporator 24. Thetrap 48 may beplaced in any suitable position desired where it will be subject to changes in the. temperatures of the environment air or, if desired, any generated heat.

' However, it has been found that in systems of this type the condenser and evaporator may be completely insulated within certain compartments of a refrigerator and the trap 48 exposed to the environment air surrounding the refrigerator where it will receive sufiicient heat to cause liquid refrigerant to be elevated to the evaporaor 24. I

In order to control the flow of liquid refrigerant to the evaporator 24 I have provided an automatic pressure responsive valve 58. which, as shown in Fig. 1, is connected between the condenser 28 and the trap 48. This valve is set so as to be responsive to changes of pressures with- 'in the system so as to allow the fiow of liquid refrigerant from the condenser 26 to the trap 48 when the pressure within the evaporator 24' reaches a predetermined high value. When this occurs the temperature of the evaporator 24 is such that there is a need for. refrigeration by that evaporator and accordingly the valve permits the flow of liquid refrigerant to the trap '48 to thus cause the fiow of liquid refrigerant to the evaporator 24 in response to that refrigeration requirement Any suitable means may be provided for cooling the condenser 26 and as herein disclosed, I have provided an automatic refrigerating system of the compression type-for automatically maintaining substantially constant temperatures within the condenser 28-so as to provide for main- Preferably the primary system 52 is intermit- 'tently operated under the control of a thermo- I taining a substantially constant temperature differential between the primary refrigerating syswherein it is liquefied and from which it is deliveredto the float valve mechanism 68. The

fioat valve mechanism 68 controls thefiow of liquid refrigerant to evaporator 51 through conduit 84. The compressor 54 is operatively connected with motor 55 for actuating motor 54'.

stat 88 which includes thermo-bulb 68 connected to evaporator 51, so as to be responsive to changes in temperature within that evaporator for opening and closing the motor circuit upon predeterv mined increase or decrease in temperatures within the evaporator 51 as is well understood. Other primary systems may be used if desired such, for example, as a block of CO2 or'the like.

While the primary system 52 may be operated at any desired temperature either above or below freezing, the secondary system may be adjusted readily for operating atany desired temperature above the temperature of the evaporator 51 of the primary system. This is accomplished by use of the adjustable valve 58.

In accordance with my invention I provide the valve 58 for controlling the flow of liquid refrig-.

erant in the secondary system and in so doing provide for maintaining a predetermined temperature differential between the primary and secondary refrigerating systems. The refrigerants used in the primary and secondary systems may be the same ordiflerent refrigerants as desired and may be any of the refrigerants now well known in the art.

Referring now to Fig. 3, the valve 58 comprises in general a casing 18 having ports 12 and 14 to which conduits 28 and 31 are connected respectively. Within the casing 18 is disposed valve proper 16 which cooperates with valve seat 18 for controlling the flow of refrigerant between conduits 31 and 28. The valve proper l6 is'carried by an annular disc 88 to which is sealed bellows 82. The opposite end of bellows 82 is sealed to an annular disc 84 whichrests upon a shoulder 85 formed in the casing 18. Upon an increase of pressure within the casing 18 the bellows 82 tends to collapse and in so doing moves the valve 16 away from its seat I8. At this time communicationis established between conduits 31 and 28. The bellows tends to collapse in opposition to compression spring 98 which continuously tends to urge the valve 18 towards seat 18. Theeffectiveness of the spring 98 may be controlled by adjustment screw 92. Preferably the annular disc 84 is sealed to the shoulder 85 so as to prevent leakage of refrigerant out of the casing and about the screw 92. By this arrangement it will be noted that when the pressure, within the evaporator 24 reaches a predeterw mined value the pressure within the liquid supply conduit 28 will beequivalent to the pressure within evaporator 24 and this pressure will be the same within the casing 18 toexert itself upon'the bellows 82 to collapse said bellows. When this takes place the valve 16 is in open position andallows liquidrefrigerant to fiow from the condenser 26 into trap 48 where the refrigerant is-subjected to heat so; as to provide a vapor lift pump forconducting said liquid refrigerant into the evaporator 24. Any setting of the valve 58 for different temperatures in the secondary system may be had as desired.

When my invention is employed, for "example, in household refrigerators, the primary refrigerant evaporator 51 may be completely insulated from environmentair surrounding the refrigerator and may be of the same construction as is now generally employed in household refrigerators for the freezing of ice cubes and the like. .These structures are well known and illustration and further description thereof is deemed unnecessary. Thus a refrigerator may be provided for the freezing of ice cubes by utilizing the primary evaporator for that purpose. At the same time the evaporator 24 may be disposed within a 75 p 2,138,012 food storage compartment which may be the' compartment 20 and utilized for proper preservation of food stuffs and the like. The evaporator 24 may be designed of suflicient size so as to properly cool the food stuffs without the collection of frost on its external surface, the temperature'of that evaporator being controlled by the valve 50, which,. as previously stated, prevents the flow of liquid refrigerant to the evaporator 24 until the evaporator '24 reaches a predetermined high temperature. If, however, it is desired to design the evaporator 24 ofa smaller size and maintain proper preservation of food stufis in the compartment 20, the same may be operated in such a manner that frost collects on its outer surface i when the primary refrigerating system is inoperation and the frost is allowed to melt off during periods when the primary refrigerating system is inoperative. If, however, it is dethat its temperature constantly below freezing, the valve 50 may be set to accomplish this, result. In this instance, however, the evaporator need not be as large-as evaporators which either do not allow the same to melt off during other periods of operation.

It will readily be apparent that the refrigerating system disclosed in Fig. 1 may be suitablefor use for other p UOses than household refrigerators, and as disclosed, it will be readily appar-. ent that adjustment may be readilyaccomplished for obtaining any temperatures desired.

When the system disclosed in Fig. 1 is used for 35 household refrigerators, it may be in' some instances desirable'to place the trap 40 in heat exchange relation to the motor compressor unit of.

the primarysystein 52 so that when there is a demand for refrigeration by the thermostat 06 4c the heat given off by the motor compressor unit 24, and this may be accomplished by merely ,placing the thermo-bulb 68 in heat exchange-relation with the evaporator 24. Asthis modification is readily understood by the foregoing description, 55 it is believed that'further description and dis closure in the drawing is unnecessary for a proper understanding of such modification.

From the foregoing it will readilybe apparent that I have provided anew and improved refrig- 60 eratin'g system of the type including primary and secondary refrigerating systems wherein desired temperatures may be maintained in the secondary system in a new and improved manner and the evaporator of the secondary system may be lo- 65 cated above the condenser of that system without in any' manner impairing the eflicie'ncy or opera- .tion of the secondary system'and that'the liquid refrigerant in-the secondarysystem is elevated byv utilizing environment temperature inside or about 7 the refrigerating apparatus. "It will also be ap-- parent, however, that artificially generatedheat may beused for applying heat-to trap 40 and that under either conditions of operation the valve 50 I serves to maintain a predetermined temperature 75 diiferential between the primary and secondary sired to continuously operate evaporator 24 so collect frost or collect frost part of the time and 3 systems. As shown in Fig. 1, the condenser 26 and evaporator 51 are positioned in a compartment which may be of, such size and construction asto. provide a storage space for food articles for storing same at low temperatures either above.

or below freezing as desired and which temperatures may be controlled by the setting of thermostat 66. Evaporator 51 maybe attached to condenser 20.

' InFig. 2 there is shown a modified-form of refrigerating system embodying features of my invention. In this figure in the drawings the numeral I00 designates a heat absorber or refrigerant evaporating element corresponding to the refrigerant evaporator 24 in Fig. 1. The evaporating element I0'0 is disposedwlthin a compartment I02 which corresponds to the inclosure 20 of Fig. 1. Associated with the evaporatingelement I00 is a condenser 1 04 which corresponds to condenser 26. A supply conduit I06 like conduit 28 .conducts liquid refrigerant from the condenser and terminates at I08 in a vessel- IIO which corresponds to vessel 3i of Fig. 1.

Vessel IIO, however, is in open communication Y with the inlet end II2 only of the refrigerant evaporator I00. A return conduit 4' corre- 'sponding to the conduit 31 of Fig. 1 connects the I outlet end IIB of the evaporator directly to'the condenser I04. A pressure responsive valve II8 and a single-tube I20, corresponding to valve 50 and traprespectively of Fig. 1, are disposed in the supply conduit I06 for regulating the flow of refrigerant to the evaporator I00. ,A conduit I22 conducts vapor from vessel IIO to a condenser I24 which may be cooled by the same meansutilized to cool condenser I04. Preferably, a heat absorbing element similar to evaporator 51 of the'primary system 52 of Fig. l is used to maintain condensers I04 and I24 .at asubstantially constant temperature. The refrigerant condensed in condenser I22 is conducted by a conduit I26 to the supply conduit I06 where it merges with refrigerant from the condenser I04. The operation of system shown in Fig. 2 is similar to the operation of system shown in Fig. 1, however conduit I22 conducts vapor directly from vessel I I'll to auxiliary condenser'I24. The main portion of the evaporated refrigerant in the systemis produced "in evaporator I00 and is conducted tocondenser I04 through conduit "4. The two condensers I04:

and I24 are housed in compartment I21 which corresponds to compartment 95. The primary system may be associated with these two c'ondensers in a manner described in connection with Fig. 1.

' denser 20 of Fig. '1 which may likewise be maintained at-a. constant temperature by means of a primary system such as that shown in Fig. 1.

A supply conduit B -corresponding to conduit 28 opens into a vessel I38 similar to vessel 3I at I40. This vessel I38 is in open communication Another modified form of a refrigerating syswith the entrance I42 to the evaporator I32. It

also communicates with the end of the evaporator' throughconduits' I44 and I46. Return conduit I48 which corresponds to'- conduit 31' conducts.

. refrigerant vapon fromjthe evaporator and vessel

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