US2142828A

US2142828A - Refrigerating apparatus

Info

Publication number: US2142828A
Application number: US478390A
Authority: US
Inventors: Harry F Smith
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1930-08-28
Filing date: 1930-08-28
Publication date: 1939-01-03
Anticipated expiration: 1956-01-03

Description

Jan. 3, 1939. H. SMlTH 2,142,828 REFRIGERATING APPARATUS Original Filed Aug. 28, 1930 2 Sheets-Sheet l ATTOR Jan. 3, 1939. F WTH 2,142,828

REFRIGERAT ING APPARATUS Original Filed Aug. 28, 1930 V v v ATTORNEY 2 Sheets-Sheet 2 Patented Jan. 3, 1939 PATENT OFFICE BEFRIGERATING APPARATUS Harry F. Smith, Dayton, Ohio, assignor, by mesne assignments, to General Motors Corporation, a corporation of Delaware Application August 28,

1930, Serial No. 478,390

Renewed September 28, 1935 17 Claims.

This invention relates to refrigerating apparatus and more particularly to improved apparatus for the cooling of liquids.

One of the objects of this invention is to provide an improved mechanically operated apparatus for the cooling of liquids and to arrange said apparatus in such a manner so that the mechanically operated means will not frequently be rendered operative.

Another object is to provide an improved apparatus for the cooling of liquids, and to provide means for preventing destructive freezing of said apparatus. I

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the invention is clearly shown. 1

In the drawings: Fig. 1 is a diagrammatic illustration, partly elevation and partly in cross-section, of a refrigerating apparatus embodying features of this invention;

Fig. 2 is a diagrammatic illustration of a modifled form of refrigerating apparatus embodying features of the invention; and 1 Fig. 3 is a top view in cross-section of the apparatus shown in Fig. 2, the view being taken on the line 3-4 of Fig. 2.

An apparatus for the cooling of liquids, ac-' cording to this invention, includes a primary refrigerating system 20 for maintaining a relatively low temperature such as for freezing, and a secondary refrigerating system 22 for the maintenance of a higher refrigerating temperature such as is suitable for cooling of liquids to be used as beverages. Thermal heat exchange means 24 including the condenser 25 for the secondary system and a gas, such as air, noncondensable at-temperatures prevailing in the secondary system are provided in the secondary system for maintaining the temperature differen- -tial with respect to the primary system in accordance with the change of temperature of the main body of liquid refrigerant in the secondary system. By this arrangement the temperature in the secondary system is maintained substantially constant as is more. fully hereinafter described, to thus prevent destructive freezing. of the liquid supply apparatus for the liquids to be cooled. In order to prevent frequent operation of the primary refrigerating system I have provided a holdover composition 28 which preferably freezes during the operation of said system at a point intermediate the starting and stopping of said system. This holdover composition is preferably an eutectic mixture, the entire body of which freezes at one temperature and which tends to delay the evaporation of refrigerant in the primary system.

Referring more in detail to the drawings, the primary refrigerating system 20 comprises in general a finned liquid refrigerant evaporator 30 of the flooded, float controlled type, and a refrigerant liquefying unit 3|. The evaporator 30 is located in the chamber 32 surrounded by the holdover composition. The liquefying unit 3| withdraws the gaseous refrigerant from the vapor conduit 35, liquefies the refrigerant and delivers it to a supply conduit 36. The liquefying unit includes the motor 31, compressor 38, and condenser 39, the motor being controlled in response to pressure within the conduit 35 and therefore in accordance with the temperature of the body of liquid refrigerant in evaporator 30 by means of an automatic switch 42 which connects the motor with the power mains 43. to maintain, normally, the said temperature within predetermined limits.

The secondary refrigerating system 22 comprises in general a vaporizer or evaporator 50 formed by a metallic member SI and containing a body of liquid volatile refrigerant, such as S02. As previously stated herein the heat exchange means 24 includes a condenser 25 of the secondary system. Preferably the heat exchange means 24 includes a closed conduit containing a volatile refrigerant. The conduit is provided with a coiled portionjlocated preferably, below the level of refrigerant in the evaporator 30, and a coiled portion forming the condensing surface of the condenser 25. The condenser of the secondary system is provided with a closed, long and relatively narrow passageway 55 formed above the vaporizer 50. The passageway "is provided with a gas pocket for the gas noncondensable at temperatures prevailing in the apparatus, which gas is provided in said secondary system in the passageway 55. Preferably the holdover chamber 22 and the vaporizing chamber 50 are insulated from the exterior and from one another by insulation 62,

The secondary refrigerating system 22 is adapted for the cooling of liquids, for instance, water. Preferably the water is cooled by passing through a conduit which is in contact with the liquid refrigerant contained in the .vaporizer in the secondary system. The conduit is provided with a bubbler 61, and a valve I by which the liquid to be cooled is subject to demand intermittently at variable rates. The conduit 55 may be connected to any suitable water pressure system and is preferably of such a length that water passing therethrough will be chilled to a temperature equal that of the liquid refrigerant in the vaporizer by the time the water passes through the entire length of said conduit.

The operation of my improved apparatus for the cooling of liquids isas follows. When the valve 68 is intermittently operated for withdrawing water through the bubbler 57, the water entering the conduit 55 is above the temperature of that to which it is finally cooled, thus giving up its heat directly to the metal wall of the conduit 65 and the latter in turn delivers this heat to the liquid refrigerant surrounding it with the result that some of the liquid refrigerant in contact with the conduit is vaporized and rises through the liquid refrigerant to the passageway 55. When this occurs a varying capacity of the condenser is obtained by the driving of said noncondensable gas in the pocket of the passageway 55 in accordance with the change of temperature of the liquid refrigerant in the secondary system. That is, the increased temperature of the liquid refrigerant in the vaporizer 50 increases the amount of evaporation in said vaporizer which in turn increases the pressure acting on the noncondensable gas in the passageway 55. As said pressure increases, the gas in the passageway 55 will be swept along the condensing surface of the condenser 25 by f'the rapid action of the evaporated refrigerant from the vaporizer 50. Since the passageway 55 is relatively narrow, the gas will be swept ahead of the rapidly moving evaporated refrigerant and in so doing said gas will be compressed. to thus allow the evaporated refrigerant to uncover only the proper amount of condensing surface of the' condenser. The area of thepassageway 55 is sufficiently small so that the rate of the diffusion of the evaporated refrigerant into the gas is considerably less than the velocity of the refrigerant vapor rushing upwardly to the condenser 25 to be condensed. As the condenser condenses the evaporated refrigerant sufiiciently to reduce the temperature of the liquid refrigerant in the vaporizer 50, the pressure on the gas will decrease, thus permitting saidgas to expand to thereby gradually cover the condensing surface to gradually reduce the rate of condensation. This arrangement limits the condensing action of the secondary system to thus maintain the desired temperature, within predetermined limits, of the liquid refrigerant in the vaporizer 50. From the foregoing it will be noted that the evaporated refrigerant from the evaporator of the secondary system uncovers a varying proportion of the condensing surface of the condenser by sweeping the noncondensable gas into the passageway 55 ahead of the evaporated refrigerant in accordance with the change of temperature of the liquid refrigerant in the vaporizer 50 of the secondary system. Thus the action of the condenser 25 is such that it maintains a substantially constant temperature in the vaporizer 50 regardless of the particular lower temperature of the condenser 25 or evaporator 30 by presenting the correct amount of condensing surface to the vaporized refrigerant of the secondary system.

In order to obtain different predetermined limits of temperature for the main body of liquid refrigerant in the vaporizer 50 the amount or quantity :f the uncondensable gas may be varied.

The more noncondensable gas used the higher the temperature will be of the liquid refrigerant in the vaporizer 55.

During the condensing action of the secondary system the heat is transferred by the heat exchange means 241 to the liquid refrigerant contained in the evaporator 30. However, the running operation of the primary system is limited by the holdover composition which surrounds the evaporator 30. Preferably the holdover composition is a eutectic mixture, the entire body of which freezes at one temperature and during one cycle of the operation of the primary system at a point intermediate the starting and stopping temperature thereof. When the holdover composition is in frozen condition it will tend to delay the evaporation of the refrigerant in the evaporator 30 to thus prevent frequent operation of the liquefying unit 3!.

Referring now to Figs. 2 and 3 there is shown a modified form of liquid cooling apparatus designated in general by the numeral 70. The apparatus it includes a primary refrigerating system l2 and a secondary refrigerating system 14. The primary refrigerating system comprises in general a finned liquid refrigerant evaporator 16 of the float controlled type having conduits TI and 18 which may be connected to a refrigerant liquefying unit of the type shown in Fig. 1. The evaporator i6 is surrounded by a holdover composition 19 preferably a eutectic mixture. The secondary refrigerating system comprises in general a vaporizer or evaporator 86 containing a body of liquid volatile refrigerant, such as 802. above which is a body of gas, such as air, noncondensable at temperatures prevailing in said secondary system. The secondary system 14 is adapted for the cooling of liquids. The liquids to be cooled are circulated through a metal vconduit 82 in contact with the liquid refrigerant in the vaporizer 80. The evaporator 12, holdover solution and vaporizer are insulated from the exterior and the evaporator 12 and holdover composition are insulated from the vaporizer by insulation 9)).

Thermal heat exchange means 9| for the systems I2 and 74 includes the condenser for the secondary system, which heat exchange means in this case is a wall between the evaporator of the primary refrigerating system and a space 94 for gas noncondensable at temperatures prevailing in the secondary system. The space 94 provides a gas pocket for said gas. When evaporation of refrigerant in the secondary system takes place, the varying capacity of the condenser is obtained by the concentration of said gas in'the space 94 substantially as in Fig. 1. Thus it will be noted that the evaporated resystem uncovers a varying proportion of the condensing surface by sweeping the gas in the space 94 ahead of the evaporated refrigerant in accordance with the change of temperature of the liquid refrigerant in the vaporizer 80 of the secondary system. As shown in Fig. 3, the part of the heat exchange means serving as a condenser for the secondary system is in the form of a cormgated wall. This arrangement provides an ample condensing surface.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerating apparatus including a primary refrigerating system including a primary liquefying apparatus and a primary evaporating means, a secondrefrigerating system having a heat exchange means for cooling a substance to be cooled, a congealingv solution in heat exe, relationship with said primary evaporating means, said congealing solution and the primary evaporating means being surrounded by insulation, and a heat exchange coupling for thermally connecting ,the primary evaporating means and the second refrigerating system.

2. A refrigerating apparatus including an enclosure including a liquid chamber containing a Volatile liquid and a vapor space above the liquid, said enclosure including a narrow passage located above the level of the volatile liquid and connected to the vapor space, a dead end pocket connected to the other end of the narrow passage, an evaporating means located in the narrow passage, said enclosure containing an-inert gas, said enclosure also containing heat exchange means in heat exchange relation with the volatile liquid in the liquid chamber.

3. A refrigerating apparatus comprising a pri- 'mary refrigerant zone, a'primary refrigerant for maintaining said zone within predetermined temperature limits, a secondary refrigerant syserant in its flow into said passageway.

'7. Refrigerating apparatus comprising means forming a long relatively narrow passageway closed at its upper end and connected to a reservoir below said passageway at the lower end, a body of liquid volatile secondary refrigerant in said reservoir, a primary refrigerating system connected to cool said passageway, inert gas in 1 said passageway, said passageway being so protem, said system including a liquid body of sec-' ondary volatile refrigerant, a relatively inert gas uncondensable at prevailing temperatures and a casing containing said secondary refrigerant and gas and including a relatively narrow passageway in thermal contact with said primary refrigerant zone and a dead end-pocket beyond said narrow passageway, the size of said passageway being such that when secondary refrigerant is evaporated from said liquid body, the resultant flow of gaseous secondary refrigerant int said passageway sweeps said inert gas into s d pocket at a rate faster than the rate of diffusion of said inert gas.

4. A refrigerating apparatus comprising a primary refrigerant zone, a primary refrigerant for maintaining said zone within predetermined temperature limits, a secondary refrigerant system, said system including a liquid body of secondary volatile refrigerant, a relatively inert gas uncondensable at prevailing temperatures, and a casing containing said secondary refrigerant and gas portioned that said inert gas is swept toward said closed end by the velocity of gaseous refrigerant in its flow into said passageway, and means controlling the operation of said primary refrigerating system in acordance with changes in refrigeration conditions.

8. In combination, a primary refrigerant sys- V tem having a heat exchange surface, an inert gas blanketing a portion of said surface, a secondary refrigerant system in thermal exchange relationship with said surface, and means whereby a variation in the temperature-pressure relationship of the refrigerant in said secondary system causes a variation in the blanketing action of the inert gas.

9. In combination, a primary refrigerating system including a primary evaporator, a secondary refrigerating system including a secondary condenser in thermal exchange relationship with said primary evaporator, and means responsive to the temperature-pressure relationship of the refrigerant in said secondary system for varying the amount of surface area of said condenser which is exposed to the secondary refrigerant.

10. In combination, a primary refrigerating system including a primary evaporator, a secondary refrigerating system including a secondary condenser in thermal exchange relationship with said primary evaporator, a low pressure refrigerant in said secondary refrigerating system,

and including a relatively narrow passageway in thermal contact with said primary refrigerant zone and a dead end pocket beyond said narrow passageway, the size of said passageway being such that when secondary refrigerant'is evaporated from said liquid body the resultant flow of gaseous secondary refrigerant into said passageway sweeps said inert gas into said pocket at a rate faster than the rate of diffusion of said inert gas, and in varying degrees in accordance with the rate of evaporation of volatile secondary refrigerant from said liquid body.

5. Refrigerating apparatus comprising means passageway, said passageway being so proportioned that said inert gas is swept toward said closed end by the velocity of gaseous refrigerant in its flow into said passageway.

1 6. Refrigerating aparatus comprising means forming a long relatively narrow passageway closed at its upper end and connected to a reserand means responsive to the temperature-pressure relationship of the refrigerant in said secondary system for varying the amount of surface area of said condenser which is exposed to the secondary refrigerant.

11. In combination, a chamber containing a low pressure volatile refrigerant, a relatively narrow passage leading upwardly from said chamber and containing inert gas, and a condensing surface intermediate the ends of said passage whereby vaporized refrigerant displaces the inert gas upwardly before coming in contact with the condensing surface and whereby the condensed refrigerant returns to the chamber with out passing through the main body of inert gas.

12. The method of refrigeration which comprises evaporating refrigerant in a first zone, leading the refrigerant vapor into a. second zone and into heat transfer relation with a condensing surface substantially surrounded by a relatively inert gas uncondensable at the prevailing temperatures, and utilizing the uncondensable gas to control the heat transfer relation between said I vapor and said condensing surface.

13. In a refrigerating system, an evaporator having a passage connected thereto, a condenser in said passage, inert gas normally surrounding said condenser, said passage being so arranged 1 that vaporized refrigerant displaces inert gas around said condenser, condenses and returns to the evaporator without passing through the main body of inert gas.

14. In a refrigerating system, an evaporator, a condenser complementary to said evaporator, means for progressively blanketing portions of the exterior surface of said condenser, said means serving to increaselthe effective condensing surface of said condenser up'on an increase in refrigerant demand. 15. The method of refrigeration which comprises cooling a surface in a first zone, causing evaporation in a second zone, surrounding a: portion 'of said cooling surface by a. relatively inert gas uncondensable at the temperatures prevailing in said zones, leading the vapors formed in said second zone into heat transfer relation to said cooling surface and utilizing said uncondensable gases for controlling the transfer of heat of said vapor to said cooling surface.

greases between said zones.

17. In combination, a refrigerant system having a heat exchange surface, means blanketing a portion of said surface, a secondary refrigerant system in thermal exchange relationship with said surface, and means whereby a. variation in the temperature pressure relationship of the refrigerant in said secondary system causes a variation in the blanketing action of said first named HARRY F. SMITH.