US2539986A

US2539986A - Cooling system for refrigerators

Info

Publication number: US2539986A
Application number: US2617A
Authority: US
Inventors: George A Brace
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1948-01-16
Filing date: 1948-01-16
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

Jan. 30, 1951 G. A. BRACE 2,539,985

COOLING SYSTEM FOR REFRIGERATORS Filed Jan. 16, 1948 l C C? zo 0 B /8 /s l B l l P 43 3/ 43/ INVENTOR. @forge A. Bra ce ATTORNEY.

at-enteci Jan. 30, 1195i 2,539,986 n oooLING SYSTEM Foa RErRIGERAToR-s George A. Brace, Highland Park, Ill., assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application January 16, 1948, Serial No. 2,617

This invention relates to the art of refrigerati'onand more particularly to a cooling system for rejecting waste heat from said system efficiently. and controllably.`

It is a particular object of the present invention to provide a cooling system especiallyaclapting action at theend of a heatingv period of the generator-absorber.

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

. The invention is diagrammatically and schematically illustrated in the accompanying drawings as applied to an intermittent absorption refrigerating apparatus of the dual unit type. The right and left hand reirigerating systems shown in the drawings are identical with each other, hence only the left hand system will be specifically described. Corresponding parts of the right hand system will beidentiiied with identical reierence characters distinguished by the addition of a prime.

.The refrigerating system per se comprises an annular generator-absorber vessel B which may contain a liquid absorbent such as water or a solid absorbent such as strontium chloride or the like. The absorbent is adapted to absorb a refrigerant such as ammonia. When heated the refrigerant is liberated from the absorbent as a vapor. Vapor liberated from the absorbent in the generator-absorber B flows through a conduit I to a tubular air cooled condenser C. rThe vapor is liquefied in the condenser C` and the liquid ows therefrom through a conduit II to the evaporator structure E. Any desired speciiic construction of evaporator. may be utilized. As illustrated herein the evaporator comprises a liquid receiver to which the conduit II is con-v nected. A pair of cooling coils 2'I and 3l open at their upper ends into the reservoir 25. The lower ends of the coils 2l and 3I receive liquid re- 9 Claims.' (Cil. 621-118) frigerant from the reservoir 25 through the conduit 35. In the preferred arrangement of this type evaporator the coil sections 3I--3I will be .arranged to refrigerate the interior of a freezing compartment. The coils 2'I-2`l will be provided with air cooling ns 38-38' positioned laterally on opposite sides oi the freezing chamber (in the interest of clarity only the ns 38 are shown in the drawing).

In the operation of the device heat is applied to the generator-absorber B to evolve refrigerant vapor. After the absorbent contained in the generator-absorber is exhausted to some predetermined degree the heating action is stopped and the generator-absorber B is cooled. This causes the absorbent therein to reabsorb vapor which lowers the vapor pressure sufficiently in the line comprising conduits II, Iii, condenser C and the evaporator E so that the refrigerant evaporates at a low temperature in the evaporator E to produce a useful refrigerating effect.,

ship with the interior wall of the annular generator-absorber B. Cooling medium vapor produced in the annular jacket I2 flows through a conduit I3 into a tubular air'cooled condenser I4 wherein it is liqueiied. Liquid cooling medium discharges from the condenser I4 through a pipe I5 into a cooling medium reservoir I6. Cooling medium is conveyed from the lower portion of the reservoir It into the upper portion of the jacket I2 through a conduit system which comprises the downwardly extending conduit il, horizontal conduit I8, a U-shaped vapor lock conduit I9 and a vertically extending conduit 20 which opens into the upper part of the jacket i2.

y An additional conduit system is connected with The conduit 22A The generator-absorber B is heated by a combustible fuel burner such as the gas burner 26 positioned therebeneath and arranged to discharge its products of combustion through a flue 39 which is positioned interiorly of the annular cooling jacket I2. 'Ihe burner 26 receives fuel from a supply conduit 28 through a conduit 29 which contains a solenoid control valve 30.

The apparatus is controlled solely by regulating the supply of fuel to the burners 26-26 by controlling the solenoid valves 30-36". The solenoid valves are each connected to an electrical supply line 32 and to switch contacts 33-33, respectively. A bridge contact 34 is adapted to connect the contacts 33-33 alternately to the other side of the electric supply line 36. As illustrated herein the bridge contact 34 is actuated by an over-center snap acting mechanism 31 which in the position shown is energizing the solenoid valve 30 to supply fuel to the burner 26. In its other position the valve 3D will be de-energized and will close itself by spring action whereas the valve 30 will be energized through the contact 33 to supply fuel to the burner 26. The snap acting mechanism is arranged to be actuated by a pair of thermostats 40-40 which are responsive to the temperatures of the generator-absorbers B and B' respectively. The thermostat 43 responsive to the generatorabsorber B, is positioned to operate the actuating link 4I of the snap acting mechanism 31. The thermostat mechanism 46', responsive to the temperature of the generatdr-absorber B', is positioned to operate the actuating link 4I, but in the opposite sense with respect to the thermostat 46. In the position shown the thermostat 4D is in collapsed, cold position, indicating that the generator-absorber B has just completed an absorbing cycle of operation. The thermostat 49' is in its fully expanded position indicating that the generator-absorber B' has just completed a generating phase of operation, hence the link 4I has been actuated to energize the solenoid` valve 33 through the contact 33 to supply fuel to the burner 26.

When the generator-absorber B has completed its generating phase of operation its temperature will rise and the thermostat 4|] will expand to actuate the snap acting mechanism 31 in a manner to de-energize the solenoid valve 30 and to energize the solenoid valve 30'. At this time the thermostat 40' will be in collapsed position because the generator-absorber B will be cold having substantially completed its absorbing period of operation.

The inverted U-shaped conduit I9 which is in the path of i'low of cooling medium from the reservoir I6 to the cooling jacket I2v is adapted to. form a uid flow blocking vapor lock in order to control the operation of the cooling system. The bight and left hand leg portions of the vaporlock` conduit I9 are heated by conduction through a metallic heat conducting element 43 which is in heat exchange relation with the bight and left hand leg portions of conduit I9. The lower end of element 43 is positioned to' be heated by burner 26. When fuel is supplied to the burner 26- it is ignited by the flash pilot structure 44' and' immediately begins to heat the heat conductor 43 as well as the generator-absorber B. Heat conducted through the element 43 quickly vaporizes cooling medium in the bight portion of the conduit I9 which forms a vapor lock and prevents further iiow of cooling medium from reservoir I6 into the cooling jacket I2. As long as heat is applied to the burner 26 the vapor lock s maintained and all of the cooling medium in circulation then ows through the generator-absorber B to remove the heat of absorption therefrom.

When the generating period of the generatorabsorber B is completed and the burner 26 is extinguished, the vapor lock in the conduit I9 will eventually collapse by condensation to restore cooling medium circulation to the cooling jacket I2. This action however has been found to require a prohibitive time lag which it is a principal object of this invention to eliminate.

TheA inverted U-shaped portion of the conduit 22, which is in thermal exchange with the bight portion of the inverted U-shaped conduit I9, also has a comparatively shallow vapor lock formed therein due to heat conducted through the conduit I9 when it is heated by the heat conductor 43. However, due to the rather remote thermal relationship between conduit 22 and heat conductor 43 this vapor lock is shallow and in some circumstances may not be very substantial. A shallow vapor lock at this point is desirable to prevent vapor formed in conduit 22 from being displaced by cool liquid from reservoir I6 which might cause premature collapse of the vapor lock in conduit I9.

That portion of the conduit structure 2I 22 and 23 on the side of the U-shaped conduit 22 closest to the bulb 24 is iilled with liquid. The major portions of the conduit 23 and the bulb 24 are exposed to atmospheric air and are therefore at substantially atmospheric temperature. When the control mechanism de-energizes burnerl 26 and energizes burner 26', heat is applied to bulb 24 and vaporizes a por-tion of the liquid therein contained. The vapor thus trapped in the dead end of the conduit system 23-24 forces cool liquid around the bight portion of condult 22 into intimate thermal exchange relationship with the inverted U-shaped vapor lock I9 in the primary cooling system. When this occurs rapid condensation takes place Within the bight portion of conduit I9 which disturbs the equilibrium of the vapor lock and causes it to collapse with great rapidity to restore cooling medium circulation to the jacket I2.

It is not essential that all the vapor in the vapor lock conduit I9 be condensed as any signiiicant localized condensation therein will upset the rather delicate balance of the vapor lock and cause uncondensed vapor to beblown into the jacket I2 from which it escapes to the condenser. By this means the thermalcontrols which are responsive to the generator-absorberI temperatures operate directly and solely upon the gas control, The coolingmedium system is controlled entirelybyy theVV application of4` heat to the generator-absorbers.

As shown in the drawings the conduit 23 which is associated with the cooling system for the generator-absorber B- is being heated by the burner 26 and has displaced cold cooling medium into heat exchange with the vapor lockI and the conduit I9 to remove the vapor lock.r This leaves a considerable portion of the conduit 23 filled with vapor. This however is not objectionable as there will be ample time duringl the absorbing cycle of operation for the vaporin this portion of conduit 23 to condense and cool substantially to atmospheric temperature'. The conduit system 2I, 22;, 23 and 24l operates by displacing cool liquid therein in the direction of the reservoir I6 under the propulsive liquid gradually ows back thereinto from the` reservoir I6 so as to recharge it with liquid.

In the foregoing structure Ythe heat applied to `any generator-absorber automatically establishes and maintains a vapor lock in its cooling system throughout its generating period of operation. Additionally the application of heat to any particular generator-absorber simultaneously and automatically vdisplaces cold liquid into heat exchange relationship with the pre-existing YSfDor lock in the cooling system of the associated generator-absorber tov restore cooling medium circulation to that generator-absorber. In .this manner rapid formation and collapse of the cool-- ingsystem ilow control vapor lock is established Without requiring anyaction by the system control mechanism and without requiring moving parts in any way associated with the cooling system. rIhe mere application of heat to either generator-absorber automatically shuts oir" the flow of cooling medium to the heated generatorabsorber and initiates flow of cooling medium to the associated generator-absorber.

H While I have illustrated` and described the invention in considerable detail, it is to be understood that various changes may be made in the arrangement, proportion and constructionI of parts without departing from the, spirit of the invention or the scope of the appended claims. I claim:

1. Refrigerating apparatus comprising a pair of intermittent absorption refrigerating systems each including agenerator-absorber and a cooling element in heat exchange relation with the generator-absorber, means for heating said generator-absorbers, means for controlling said heating means toheat said generator-absorbers alternately with respectvto each other, a cooling system including a pair of conduits each having l an inverted U-shaped part adapted to form a cooling medium flow preventing vapor lock when heated, each of said cooling elements being corinected to a'v separate one oi said conduits to receive cooling medium therefrom, means for heating the upper part of each of said U-shaped conduits when the generator-absorber to which it controls cooling medium flow is heated, and a pair of elongated dead ended. conduits connected to receive liquid cooling medium from said cooling system, each of said conduits having a portion in heat exchange relation with a separate one of said U-shaped conduits and its dead ended. portion positioned to be heated simultaneously with the generator-absorber to which cooling medium is supplied through the other of said U-shaped conduits.

2. In a refrigerator of the intermittent absorption type having a generator-absorber provided with a cooling means, a cooling system for the generator-absorber connected to circulate a cooling medium through said cooling means including heat operated how control means operative when heated to stop iiow of cooling medium to said cooling means, heat operated means operative when heated to render said heat operated flow control means operative to allow flow of cooling medium to said cooling means, means for heating said generator-absorber and said heat operated flow control means simultane- 6a ously, means forr heating said second mentioned heat operated means, and control means for successively activating said heating means.

3. In a refrigerator of the intermittent absorption type having a pair of generator-absorbers each provided with a cooling means, a cooling system for the generator-absorbers connected to circulate a cooling medium through said cooling means including a pair of heat operated flow control means each arranged when heated to' stop the ow of cooling medium to a distinct one of said cooling means, a pair of heat operated structures each operative when heated to render a distinct one of said flow control means operative -to allow flow of cooling medium to said cooling means, and means for heating said generator-absorbers alternately with respect to each other and for simultaneously heating the iiow control means for controlling cooling medium flow to the heated generator-absorber and the heat operated structure for rendering the other flow control means operative to allow flow of cooling medium to the cooling means in heat exchange relation with the unheated generatorabsorber. f

4. In a refrigerating apparatus a pair of refrigerating systems each including a generatorabsorber and a cooling element in heat exchange relation kwith the generator-absorber, a cooling system for passing a volatile cooling medium through said cooling elements comprising heat rejecting means connected to receive heated cooling medium from said cooling elements, separate means for conveying cooling medium from said heat rejecting means to said cooling elements each including aninverted U-shaped conduit adapted to form a cooling medium iloW preventing vapor lock when heated, a pair of dead ended conduits each connected to receive liquid cooling medium from said heat rejecting means and each having a portion in .heat .exchange relation with the bight portion of a-separate one of said U- shaped conduits, and-'means for heating said g'enerator-absorberssuccessively and for heating 'the bight portion of the U-shaped conduit controlling cooling medium flow to the cooling element of the heated generator-absorber and the dead ended portion of the dead end conduit in heat exchange relation with the U-shaped conduit controlling the flow of cooling medium to the cooling element of the unheated generator-absorber simultaneously'with the heated generator-absorber.

5. In a refriger-ating apparatus a pair of refrigerating systems each including a generatorabsorber and a cooling element in heat exchange relation with the generator-absorber, a cooling system for passing a volatile cooling medium through said cooling elements comprising heat rejecting means connected to receive heated cooling medium from said cooling elements, separate means for conveying cooling medium from said heat rejecting means to said cooling elements each including an inverted U-shaped conduit adapted to form a cooling medium flow preventing vapor lock when heated, a pair of cooling conduits each connected to receive liquid cooling medium from said heat rejecting means, each of said cooling conduits having a portion in heat exchange relation with the bight portion of a separate one of said U-shaped conduits and an elongated part more remote from said heat reljccting means than said heat exchange portion exposed to cooling air, and means for heating said generator-absorber successively and for heating the bight portion of the U-shaped conduit controling cooling medium flow to the cooling element of the heated generator-absorber and a part of the elongated conduit in heat exchange relation with the unheated U-shaped conduit simultaneously with the unheated generatorabsorber.

6. In an intermittent absorption refrigerating system having a generator-absorber, a cooling element in heat exchange relation with the generator-absorber, a cooling system for circulating a cooling medium through said cooling element including a part forming a cooling medium flow blocking vapor trap, means for intermittently heating said generator-absorber and said part to vaporize cooling medium and prevent cooling of said generator-absorber while it isbeing heated, and apparatus for cooling said part comprising a iluid filled structure having one portion thereof in heat exchange with said part, a vapor trap portion and a portion between said rst mentioned portions exposed to cooling air whereby cool liquid is displaced from said vapor trap portion When vapor is formed therein into heat exchange relation with s-aid part to condense vapor therein, and means for heating said vapor trap portion alternately with said generator-absorber.

7. Refrigerating apparatus having a pair of generators which are alternately heated and cooled in out of phase relationship with each other in operation, means for owing a cooling medium in heat exchange relation with each of said generator-absorbers including a pair of heat responsive cooling medium flow control parts operative when heated to prevent flow of cooling medium therethrough, each of said heat responsive parts being connected to control the ilow `of cooling medium in heat exchange relation with a different one of said generator-absorbers, a pair of heat operated cooling means each arranged to cool a diierent one of said heat responsive flow control parts, heating means, and means for controlling said heating means to apply heat to each of said generator-absorbers intermittently in out of phase relation to each other and to apply heat simultaneously with the application of heat to each of said generatorabsorbers to the heat responsive part controlling the ilow of cooling medium to the generator absorber being heated and to the heat operated means for cooling the other heat responsive part.

8. In a heat operated refrigerating system haii-f ing a pair of parts which are alternately heated and cooled in out of phase relation to each other; the combination therewith of a cooling system for said parts including a pair of heat absorbing elements each in heat exchange relation with a distinct one of said parts, a heat dissipating means, means providing for circulation of a cooling medium between said he-at dissipating'mcans and said heat absorbing elements including a pair of heat responsive cooling medium flow control means each connected to control cooling medium flow to a distinct one of said heat absorbing means and operative to interrupt cooling medium iiow when heated; a pair of heat operated cooling means each having a section in heat exchange relation with a distinct one of said ow control means and operative when heated to cool said flow control means; heating means; and means for controlling said heating means to heat each of said parts intermittently and in out'of phase relation to each other and simultaneously to heat the flow control means controlling cooling medium ow to the heated part and the heat operated cooling means for cooling the other ow control means.

9. In a refrigerating system having a part which is alternately heated and cooled in operation, a cooling means in heat exchange relation with said part, means for supplying a cooling medium to said cooling means including a heat REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,627,808 Schurtz May 10, 1927 2,001,142 Knight May 14, 1935 2,021,994 Hainsworth Nov. 26, 1935 2,340,886 Af Kleen Feb. 8, 1944