US2314064A

US2314064A - Refrigeration

Info

Publication number: US2314064A
Application number: US304638A
Authority: US
Inventors: Carl T Ashby
Original assignee: Servel Inc
Current assignee: Servel Inc
Priority date: 1939-11-16
Filing date: 1939-11-16
Publication date: 1943-03-16
Anticipated expiration: 1960-03-16

Description

March 16, 1943. c. T. AsHBY REFRIGERATION Filed Nov. 16, 1939 2 Sheets-Sheet 1 Patented Mar. 16, 1943 UNITED STATES PATENT oFFlcE 2,314,064 nnFmGERA'rroN Carl T. Ashby, Evansville, Ind., assgn'or to Servel,

Inc., New York, N. Y., a corporation of Dela- Ware Application November 16, 1939', Serial No. 304,638 claims. (crea- 119.55

My invention'relates to refrigeration, and more y particularly concerns cooling effected in a refrigerator cabinet.

It is an object ofthe invention to provide an improvement for cooling a refrigerator cabinet whereby several places of cooling are obtained -in one or more of which a higher humidity may be ment so that the air in the separate chamber is.

maintained at a higher humidityrwith less dehydration of food products stored therein.

Another object of the invention is to provide.

several places of cooling with the aid of a refrigeration system having a plurality of cooling elements, the system being so constructed and.

arranged that under all operating conditions liquid refrigerant is delivered to the cooling elements in such a manner that one of the cooling elements is capable of maintaining one of the places of cooling at a relatively high humidity.

The invention, together with the above and -other objects andradvantages thereof, will be ,in section, of a refrigerator embodying the invention;

Fig. 2 is a front elevation of the refrigeratorv with which the refrigeration system in Fig. 1 is associated, the door being in its open position;

Fig. 3 is an enlarged fragmentary view taken on l lines 3 3 of Figs. 2 and 4; v

Fig. 4 is a vertical sectional view taken on line 4 4 of Fig. 3;

Fig. 5 is a side vertical sectional view taken on line 5 5 of Fig. 4; and

Fig. 6 is a vertical viewv taken on line 6 6 of Fig. 4.

Referring to Figs. l and 2, I havevshown the.

invention embodied in a refrigerator comprising a cabinet I0 having an inner Ametal shell I I arranged to be supported within an outer metal shell I2 and insulated therefrom with any suitable insulating material I4. The inner shell I I forms a thermally insulated storage space I5 into which access maybe had Iby a door I6 hinged to the front of the cabinet. Within the storage space I5 are arranged several cooling elements which together constitute a cooling unit or evaporator I'I of a refrigeration system.

The cooling unit or evaporator I'I forms a part of a refrigeration system of a uniform pressure absorption type, generally as described in Patent No. 2,037,782 to William R. Hainsworth, in which an auxiliary pressure equalizing gas is employed.

In addition to the cooling unit or evaporator I'I, such a system includes a generator I8, a condenser I9, and an absorber 20 which are interconnected in a manner well known in the art and` which will briefly be described hereinafter. The

system contains a solution of refrigerant in absorption liquid, such as ammonia in water, vfor example, and also an auxiliary agent or inert gas, such as hydrogen.

y The generator I8 is heated in any suitable manner, as by a gas burner 2I, for example.

vduits

24, 25 and 26, as will presently be de scribed.

Refrigerant fluid in evaporator I'I evaporates and diffuses into inert gas which enters the lower part thereof through a conduit 21. 'I'he refrigerant iiuid in evaporator I1 evaporates and diffuses therein into the inert gas to produce a refrigerating effect. The rich gas mixture of refrigerant vapor and inert gas formed in evaporator I1 flows from the upper part thereof through

conduits

28 and 29, inner passage 30 of a gas heat exchanger 3|, and conduit 32 into the lower part of absorber 20.

In absorber 20 the rich gas mixture flows counter-current to downwardly flowing weak absorption liquid which enters through a conduit 33. The absorption liquid absorbs refrigerant vapor from the inert gas, and inert gas weak in refrigerant flows from `absorber 20 through a conduit 34, outer passage 35 of gas heat exchanger 3|, and conduit 21 into the lower part of evaporator I1. A

Absorption liquid enriched in refrigerant ows from the lower part of absorber 20 through a conduit 36, outer passage of a liquid heat exchanger 31, and conduit 38 into generator I8. Liquid is raised in the generator by a thermosiphon tube 39 and flows back to the generator through standpipe 22. Refrigerant vapor expelled out of solution in generator I8, together with refrigerant vapor entering through thermosiphon tube 39, flows upwardly through standpipe 22 and conduit 23 into the condenser I9, as explained above.

The absorption liquid from which refrigerant has been expelled flows from generator I through a conduit 4I), inner passage of liquid 'heat exchanger 31, and conduit 33 to the upper part of absorber 20. This circulation of absorption liquid results from the raising of liquid by thermosiphon tube 39.

Heat liberated with absorption of refrigerant vapor in absorber 2D is transferred 'to a suitable cooling medium which circulates through a coil 4I arranged in heat exchange relation with the absorber. The coil 4I isconnected by

conduits

42 and 43 to an air-cooled condenser 44. The coil 4I, condenser 44, and connecting

conduits

42 and 43 form a closed circuit which is partly filled with a volatile liquid that vaporizes in coil 4| and liquees in condenser 44. Liquid evaporating in coil 4I takes up heat from absorber 20, and the vapor liquefying in condenser 44 gives up heat to surrounding air.

The outlet end of condenser I9 is connected by conduit 45, vessel 46, and conduit 41 to the gas circuit, as at the upper end of conduit 29, for example, so that any inert gas may pass through the condenser and flow into the gas circuit. Refrigerant vapor not liquefied in condenser I9 flows through conduit 45 to displace inert gas in vessel 46 and force such gas through conduit 41 into the gas circuit. In this manner the total pressure in the system is raised where- -by an adequate condensing pressure is obtained to insure condensation of refrigerant vapor in condenser I9.

The circulation of gas in the gas circuit including evaporator I1 and absorber 20 is due-to the difference in specific weight of the columns of inert gas rich and weak, respectively, in refrigerant vapor. Since the rich gas is heavier than the weak gas, a force 'is produced or developed for causing flow of the rich gas from evaporator I1 to absorber 20 and flow of weak gas from absorber 26 to evaporator I1.

The evaporator I1 includes an upper cooling element 48, an intermediate cooling element 49, and a lower cooling element 50. Liquid refrigerant entering upper cooling element 48 through conduit 24 flows downward in counter-flow to inert gas which flows upwardly and enters lower cooling element 50 through conduit 21. Liquid refrigerant also enters intermediate cooling element 49 through conduit 25 and lower cooling element 50 through conduit 26, as explained above, such liquid refrigerant flowing countercurrent to the upwardly owing inert gas. Since the inert gas flows 'first through the lower cooling element 50 and then through intermediate cooling element 49 and lastly through upper cooling element 48, the gas in upper cooling element 48 contains a greater amount of refrigerant vapor than the gas in the intermediate and lower cooling element 49 and '50, and the gas in intermediate cooling element 49 contains a greater amount of refrigerant vapor than the gas in lower cooling element 50. The partial pressure of refrigerant vapor is, therefore, higher in cooling' element 49 than in cooling element 50, and evaporation of liquid refrigerant takes place at a higher temperature in the intermediate cool ing element than in the lower cooling element 50. Also, the partial pressure of refrigerant vapor is higher in upper cooling element 48 than in intermediate cooling element 49, and evaporation of liquid refrigerant takes place at a higher temperature in the upper cooling element than in the intermediate cooling element The intermediate cooling element 49 is provided with a plurality of heat transfer fins 5I to provide a relatively extensive heat transfer surface for cooling air in storage space I5. Air cooled by thermal transfer with intermediate cooling element49 flows downward in space I5 to replace warmer air which flows upward and passes over the surfaces of the intermediate cooling element.

The lower cooling element 50 is arranged in heat exchange relation with a shell 52, as shown Amost clearly in Fig. 4, the shell 52 having a plurality of compartments 53 to receive trays 54 for freezing ice cubes and the like. The shell 52 has a limited heat transfer surface which may be employed to assistintermediate cooling element 49 for cooling air in storage space I5.

Thevupper cooling element 48 is arranged in a housing or casing 55 to provide a separate chamber 56 within storage space I5. 'Ihe upper cooling element 48 is located in the upper part of separate chamber 56 and provided with a plurality of heat transfer fins 51 to provide a relatively extensive heat transfer surface for cooling air in chamber 56.

In order to locate the

cooling elements

48, 49 and 50 of evaporator I1 in storage space I5, the rear insulated wall of the space is provided with an opening to receive a removable wall section 58. The conduits connecting evaporator I1 and the other parts of the refrigeration system' extend through the removable wall section 58. As

shown most clearly in Figs. 4 and 5, the casing 55 is secured at 59 and 60 to the inner shell II to hold the casing in position within storage space I5. A door 6I is pivotally mounted at the front of casing 55 to provide access into the sep- 5 arate' chamber 55.

The lower cooling element 50 is normally operated below the freezing temperature of water andforms the ice freezing portion of evaporator I1. The intermediate cooling element 49 operates at a higher temperature than lower cooling element 50, as explained above, and is employed primarily for cooling air in space I5 to maintain the latter at a low temperature for properly preserving foods stored therein.

The air in chamber 56 is maintained at a higher humidity than that in space I5 with the vresult that less dehydration of food products takes place in this chamber. This is due to the fact that cooling element 48 operates at the highest temperature of any of the cooling ele-,- ments. -so that lessl water vapor is condensed from air in chamber 56 which flows in thermal contact with upper cooling element 48.

With the above described improvement, it will be clear that several places of cooling are provided in a refrigerator cabinet with one ofthe places being maintained at a relatively high humidity. The separate chamber. 56 is eifectively cooled b'y locating the upper or highest temperature cooling element 48 in the upper part of casing 55. When the door 6I of casing 55 is closed substantially no circulation of .air takes place between storage space I5 and chamber 56,' so that there is no displacement of air at a relatively high humidity in chamber 56 by air at a lower humidity in storage space I5. While the lowest temperature cooling element 50 has been described above as being employed to assist intermediate cooling element 49 for cooling air in storage space I5, the lower temperature-cooling element 50 may be insulated, if desired, and intermediate cooling element 49 may be employed to effect cooling of storage space I5. Cooling of air in storage space I is also effected by air flowing in thermal contact withV casing 55. By providing chamber 56, however, a' sepa, rate space for storing food is obtained which is at a sufficiently low temperature for food preservation and yet is maintained at a relatively high humidity to lessen dehydration of foods. v

In order to keep evaporator II in a Ldesired temperature range, the burner 2l may be controlled in response to a temperature condition affected by evaporator I1, as shown in Patent No. 2,123,921 to Andersson, for example, -the disclosure of which may be considered to be incorporated in this specification. If all of the liquid refrigerant formed in condenser I9 were delivered to the upper cooling element 48 and thence through the intermediate and

lower cooling elements

49 and 50, the upper cooling element under certain operating conditions, as at low load, for example, may reach a lower temperature than desired. In order that upper cooling element 48 will always be at a temperature to insure maintenance of a relatively high humidity in chamber 56, liquid refrigerant first formed in condenser I9 is delivered to the intermediate and

lower cooling elements

49 and 50, and liquid refrigerant subsequently formed in the condenser is delivered to upper cooling element 48." One manner of accomplishing this is shown in Fig. 1 wherein refrigerant vapor expelled from solution in generator IIl fiows upwardly through conduit 23 into a first condenser section I9a in which vapor is liquefied. Liquid refrigerant formed in condenser section I9a iiows through

conduits

62 and 25 ntothe upper part ofv intermediate cooling element 49 and thence int lower cooling element 50.

Refrige'rant vapor not liquefied in the first condenser section |9a flows therefrom through the upper part of conduit 62 and a conduit 63 into a second condenser section |917 in which v apor is liquefied. Liquid refrigerant formed in condenser section I9b flows through

conduits

64 and 26 into lower cooling element '.i 0.-11 Refrigerant vapor not liquefied in second condenser section I9b fiows through the upper part of conduit 64 into a third condenser section I9c in which vapor is liquefied. Liquid refrigerant formed in condenser section I9c. ows through conduit 24 into the upper cooling element 48.

Instead of delivering liquid refrigerant from second condenser section |9121v into the .lowercooling element 59, liquid refrigerant may be conducted from this condenser section into upper cooling element 48. ByY taking into consideration the manner in which liquid refrigerant is delivered to the several cooling elements of evaporator I'I, upper cooling element 48 can always be maintained in a desired temperature range under the different operating conditions encountered. Thus, when the heat input to generator I8 by burner `2I is reduced and less refrigerant vapor is expelled from solution at low load, all of the liquid formed in condenser, I9 will not be delivered to upper cooling element -and liquid` refrigerant ows from the second condenser section I9b through

conduits

64 and 26 into lower cooling element 50. Since no refrigerant vapor is liquefied in the third condenser section I9c, under the operating `conditions assumed, no liquid refrigerant is supplied through conduit 244 into the upper cooling element4l. However, when the load increases and refrigerant vapor is expelled from solution in l generator I0 at such a rate that allof the refrigerant vapor is not liqueed in the first and second condenser sections I9a and I9b, and refrigerant vapor passes into thethird condenser section |90, as explained above, liquid refrigerant is then supplied to the upper cooling element 48. In the foregoing explanation and in the claims the word load is intended tomean the quantity of heat external of the refrigeration apparatus that is removed per unit of time by the cooling unit or evaporator I1.

While a single embodiment; of the invention -has been shown and described, such variations and modifications are contemplated as fall .within the true spirit and scope of the invention, as pointed out in the following claims.

What is claimed is:

1. A refrigerator having a thermally insulated storage space, an absorption type refrigeration system including upper, intermediate, and lower cooling element .connected for upward flow of auxiliary agent in series and downward flow of cooling agent in the presence of auxiliary agent, and a compartment in the upper part of said storage space arranged to be cooled by said upper cooling element, said intermediate cooling element being disposed in the upper part of said storage space, said lower cooling element having thermally connected therewith a chamber for freezing ice and the like, said system including a condenser having a plurality of sections in which vaporous cooling agent is liquefied and from which the liquid cooling Aagent is 'delivered to said cooling elements, and connections whereby liquid formed in one of saidcondenser sections is delivered to said intermediate and lower cooling elements, and liquid subsequently formed in another of said condenser sections is delivered to said upper cooling element.

'2. A refrigerator having a thermally insulated storage space, an absorption type .refrigeration system including upper, intermediate, and lower cooling elements connectedy for upward ow of auxiliary agent in series and downward iiow of cooling'agent in the presence of the auxiliary cluding a condenser having three sections con-4 nected in series to receive vaporous cooling agent, the section in which vapor is first liquefied being connected to deliver liquid cooling agent to said intermediate cooling element, the section in which Vapor is subsequently liqueed being connected to deliver liquid to said lower cooling element, and the section in which Vapor is last liquefied beingconnected to deliver liquid to said upper cooling element.

3. A refrigerator having a thermally insulated storage compartment, a separate high humidity compartment, and refrigeration apparatus for cooling said compartment and employing evaporation of refrigerant uid in the presence of inert gas, said apparatus including a plurality of evaporators in which said evaporation may take place and through which said inert gas flows serially so that evaporation of liquid takes place ,at different temperatures in said different evaporators, one of said evaporators being arranged for freezing water or the like, another of said evaporators at a higher temperature being arranged to cool air in said storage compartment, and a third one of said evaporators at a still higher temperature being arranged to cool air in s'aid high humidity compartment, and said refrigeration apparatus including a liquid supplier which supplies liquid to said last evaporator only when the load is at or above a predetermined value.

4. A refrigerator having a storage compartment, a high humidity, compartment in heat exchange relation with said storage compartment, refrigeration apparatus comprising a plurality of parts and connections therebetween, said parts including a liquid refrigerant supplier and a plurality of cooling elements in which liquid refrigerant evaporates to produce a cooling effect, each of said compartments being arranged to be cooled by one of said cooling elements, said connections including conduits for conducting liquid from said liquid refrigerant supplier to said cooling elements, and said parts including said connections being so constructed and arranged that said cooling element for said high humidity compartment is capable of producing a cooling effect by evaporation of liquid refrigerant therein only when the load is at or above a predetermined value.

5. A refrigerator having a plurality of compartments, one of ,Said compartments being in heat exchange relation with another of said compartments, refrigeration apparatus comprising a plurality of parts and connections therebetween, said parts including a liquid refrigerant supplier and a plurality of evaporators in which liquid refrigerant evaporates to produce a cooling effect, said evaporators being operable at different temperatures, with each of said compartments being arranged to be cooled by one of said evaporators, said connections including conduits for conducting liquid from said liquid refrigerant supplier to said evaporators, and said parts including said connections being so constructed and arranged that one of said evaporators for cooling one of said compartments is capable of producing a cooling effect by evaporation of liquid refrigerant therein only when the load is at or above a predetermined value.

CARL T. ASHBY.