US2500778A

US2500778A - Refrigerator having an automatically controlled secondary refrigerant system

Info

Publication number: US2500778A
Application number: US747809A
Authority: US
Inventors: Raymond E Tobey
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1947-05-13
Filing date: 1947-05-13
Publication date: 1950-03-14
Anticipated expiration: 1967-03-14

Description

March 14,1950 R. E. TOBEY 2,500,778

REFRIGERATQR HAVING AN AUTOMATICALLY CONTROLLED SECONDARY REFRIGERANT sysma Filed'ligy 13, 1947 2.;Sheets-Sheet 1 QAgTZEfSSES: 6.14

March 14, 1950 R E TOBEY 77 REFRIGERATOR HAVINd AUTOMATICALLY CONTROLLED SECONDARY REFRIGERANT SYSTEM Filed May 13, 1947 2 Sheets-Sheet 2 FIG.6.

INVENTOR Ramouo E. ToaEY ATTORNEY Patented Mar. 14, 1950 ICALLY CONTROLLED SECONDARY REFBIGEBANT SYSTEM Raymond E. Tobey, Springfield, Mesa, assignor to Westinghouse Electric Corporation, East Pittsburgh, l'a., a corporation of Pennsylvania Application May 13, 1947, Serial No. 747,809

1 This invention relates to refrigeration apparatus and more especially to apparatus employing a secondary refrigerant system for cooling a compartment. It is a continuation-in-part of my application, Serial No. 720,888, filed January 8, 1947, now abandoned.

It is an object of this invention to provide a 18 Claims. (Cl. 62-125) novel means for controlling the refrigerant flow in a secondary refrigerant system.

It is another object of the invention to pro vide a valve for controlling the flow of a refrigerant in a secondary. circuit, which valve is controlled by the temperature of the compartment cooled by said refrigerant.

It is a further object of the invention to accelerate the response of the secondary circuit when refrigeration is required.

These and other objects are eiiected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a side elevation of a refrigerator cabinet embodying the invention;

Fig. 2 is an enlarged section on the line 11-31 of Fig. 1, showing the refrigerant passages in a somewhat diagrammatic form;

Fig. 3 is an enlarged sectional view of the flow-controlling device of this invention; v

Fig. 4 is a view similar to Fig. 2 but showing a modification of the invention;

Fig. 5 is a sectional view on the line V-V of Fig. 4;

Fig. 6 is an enlarged sectional view of the flowcontrolling device of the modification of the invention shown in Fig. 4;

Fig. 7 is a sectional view on the line VII-VII of Fig. 6; and

Fig. 8 is a sectional view on the line VIII-VIII of Fig. 6.

Referring to the drawing for a detailed description of the invention, the reference numeral 10 designates a refrigerator cabinet having an insulated food storage chamber 12 in the upper portion of the cabinet and a machine chamber 14 in the lower portion thereof. The food chamber I2 is divided by an insulated horizontal partition 18 into an upper compartment 18 for the freezing of foods and a lower compartment 26 for general refrigerated storage.

The upper compartment 18 is cooled by a mechanical refrigeration apparatus which includes a primary evaporator coil 22 supplied with a volatile refrigerant by the primary condenser 24 through a capillary tube 26. The primary condenser 24 receives compressed refrigerant vapor through a tube 28 from a refrigerant compressor (not shown) located in a sealed casing 30. The refrigerant compressor withdraws refrigerant vapor from the evaporator coil 22 through a tube 3|, a portion of which is in thermal heat-absorbing relationship with a portion 33 of the capillary tube 26. The refrigerant compressor is driven by an electric motor (not shown) also located in the casing 30 and energized through the electrical conductors 32. A thermostatically-controlled switch 34 is located in one of the conductors 32 to regulate the compressor motor. The thermostatic switch 34 is controlled by a metal bellows 36 which is subiected toa pressure of avolatile fluid located in a bulb 38, which bulb is subjected to the temperature of the uppercompartment It. It will be apparent from this that the thermostatic 2o switch controls the motor in response to the temperature of the upper compartment 18 and holds the temperature of this compartment substantially constant.

The lower compartment 20 is cooled by a secondary volatile refrigerant circuit comprising a tube having a condensive portion 48 located in the upper compartment I8 and in heat transfer relationship with the primary evaporator coil 22. The tube 46 also includes an evaporative portion 50 located in the lower compartment 20 to cool the same.

The apparatus for controlling the temperature of the lower compartment 20 comprises a vessel 52 adapted to receive the refrigerant condensed by the condensive portion 48 through a tube portion 54. A conduit portion 56 is located directly below the tube portion 54 to receive the liquid refrigerant issuing therefrom. The conduit portion 56 connects with the lower end of the evaporative portion 50 of the tube- 46. The vessel 52 is surrounded by-thermal insulating material and is located in a portion of the cabinet III which is warmer than the condensive portion 48, so that a slow vaporization of the liquid refrigerant, which may be in the vessel 52, takes place. The vaporization of the refrigerant liquid in the vessel 52 may be increased by placing a portion 55 of the capillary tube 25 in heat transfer relationship with the vessel 52. The portion 55 of the capillary tube 26 is preferably a portion located between the portion 33 in heat-absorbing relationship with the suction tube 3! and the primary evaporator coil 22.

A baille 58 is interposed between the tube portion 54 and the conduit portion 56 to at times 3 deflect the liquid refrigerant issuing from the tube portion 54 into the vessel 52. The baffle 58 a is pivoted in a support 88 secured to one side of the vessel 52 in such a manner that the baflie 58 may be rotated in clockwise direction from the interposing position just described and shown in full lines in Fig. 3, to a second position shown in dotted lines in Fig. 3. In the second position, the baflle 58 rests against a stop 59 and does not interfere with the gravitational flow of refrigerant liquid from the tube portion 54 to the conduit portion 58. The conduit portion 58 need not be located directly below the tube portion 1 54 provided the vane 58 is formed to deflect the refrigerant liquid into the tube portion 54 when in the second position.

A horizontal extension 82 is provided at the lower end of the baflie 58 and is engaged by means of springs 8| and 83 between an upper metal bellows 84 and a lower metal bellows 85 which two bellows provide the moving force for the battle 58. The interior of the upper metal bellows 84 communicates through a tube 88 with a bulb 88. The bellows 84, the tube 88, and a substantial portion of the bulb 88 is filled with a volatile liquid 88, and the bulb 88 is subjected to the temperature of the lower compartment 28 so that the pressure of the volatile fluid 88 expands the bellows 84 and biases the baffle 58 toward the dotted position in Fig. 3 when the temperature of the lower compartment 28 rises.

The movement of the baffle 58 to the dotted position is opposed by the spring 83 and the lower bellows 85. This bellows 85 communicates with a chamber I8, and both the bellows and the chamber. I8 are located in the vessel 52 in thermal contact with the contents thereof. The

bellows 85 and chamber 18 are charged with a noncondensable gas such as air. The function of the bellows 85 is to compensate for the efiects of changes in the pressure of the secondary refrigerant circuit. These changes tend to cause movement of the bellows 84 by acting on the exterior thereof. The changes in pressure of the secondary refrigerant circuit are caused by changes in the temperature of the volatile refrigerant liquid therein, and these changes in temperature, in turn, are caused by the changes in location of this liquid. When the liquid is chiefly in the vessel 52, it is quite cold, and when it is located mainly in the evaporative portion 58 of the tube 48, it is at a higher temperature.

The bellows 85 also compensate for changes in the temperature of the primary evaporator coil maintain contact with the extension 82 when both bellows 84 and 85 contract.

The volume of the chamber I8 is so chosen that when the temperature of the volatile liquid in the secondary refrigerant circuit decreases (thereby causinga decrease in the pressure in the vessel 52), the resulting tendency of the upper bellows 84 to expand is approximately offset by the tendency of the lower bellows 85 to expand due. to the combined efiect of the decrease in the pressure in the vessel 52 and the decrease in The purpose of the springs 8| and 83 is to bellows 84 and 88 are of the same size, if the refrigerant in the secondary circuit is dichlorodifluoromethane (F-12), if the fluid in the bellows 84 and bulb 89 is methyl chloride, and if the temperature to be maintained in the lower compartment 28 is about 40 F., then the volume of chamber I8 should be from three to four times the volume of the bellows 85, and the pressure of the gas in the bellows 85 and chamber I8 should be such that it will effect operation of the baffle 58 at the temperature desired in the lower compartment 28. I

It will be apparent from the above that whenever the temperature of the lower compartment 28 is considerably above the desired temperature, the liquid refrigerant from the condensive portion 48 of the secondary refrigerant circuit flows downwardly into the evaporative portion 58 thereof and cools the lower compartment 28. On the other hand, when the temperature of the lower compartment'28 is considerably below the desired temperature, the baffle 58 will deflect all of the refrigerant flowing from the condenslve portion 48 into the vessel 52 and thereby starve the evaporative portion 58 of the circuit of liquid refrigerant. At the desired temperature, the baiiie 58 will assume an'intermediate position so that the refrigerant liquid supplied to the evaporative portion 58 will absorb the heat leakage into the lower compartment 28. The volume of the vessel 52 below the entrance to the conduit portion 58 is large enough to contain all of the refrigerant liquid condensable from the refrigerant in the secondary volatile refrigerant circuit by the condensive portion 48 thereof.

Since the vessel 52 is warmer than the condensing portion 48, a portion of the refrigerant liquid in the vessel 52 will continually vaporize and this vapor will be condensed in the condensive portion 548 and be returned to the vessel 52 by the baflie .58. This slight circulation of refrigerant is necessary so that refrigerant liquid is available to flow down the conduit portion 58 when the baflie 58 is moved clockwise. Continued vaporization of the refrigerant liquid in the vessel 52 will supply additional refrigerant vapor to the condensive portion 48, which thereupon is transferred to the conduit portion 58 as refrigerant liquid.

The evaporative portion 58 of the tube 48- is shown as located in the lower compartment 28 for the sake of clearness. In the preferred construction, however, it is located in the heat insuEation 5I of the lower compartment 28 and in heat transfer relationship with the inner metal liner 53 thereof.

A modification of the invention is shown in Figs. 4, 5 and'6. In this modification, parts identical with those of the first-described modification are provided with the same reference. numerals. The primary evaporator coil I 28 and the tube I28 'of the secondary volatile refrigerant circuit are shown as located against the side wall of the inner liner 53. The vessel I38 which encloses the actuating mechanism of the secondary circuit is located in the heat insulation 5I of the refrigerator cabinet I3I. The bulbs 98 and I32 have similar functions as the bulbs 88 and siphon tube 6.

trough and is carried by a strip of metal I8. Two

ears 88 integral with the strip I6 are bent at right angles to the strip 18 and each car 88 is perforated to provide a bearing which engages the vertical pin I4. The lower ear 88 rests on a spacer 82 encircling 'the pin 14. A rearward extension 84 of the strip I8 carries a magnetic armature 86 having pole pieces adjacent the walls of the casing 16.

A permanent magnet 88 is supported by arms 68 pivoted on the protruding ends of the pins I4. The pole pieces 82 of the magnet 88 are adapted to swing through the same are as the poles of the armature 86 and draw the armature 86 with them. The end wall 84 of the casing I6 is rounded to avoid interference with the movement of the magnet 88.

The magnet 88 is moved by a bellows 66 similar in function to the bellows 64 of the modification shown in Figure 3. A spring I88 opposes the pressure of the bellows 96 and the pressure of this spring I88 on the magnet 88 may be varied by adjusting a screw I82. Changing the pressure of the spring I88 changes the temperature at which the lower compartment is maintained.

The placing of the bellows 86 outside of the refrigerant passages of the secondary system simplifies the apparatus by eliminating the compensating bellows 65 of Figure 3. The bellows 96 and the magnet 88 are enclosed by walls I83, one of which carries the adjusting screw I82, and another of which carries the bellows 96.

The refrigerant liquid from the condensive portion 48 enters the casing I6 through the tube portion 54 andflows downward through the casing I6 and through a tube I84 into a chamber I86 if the baffle I2 is in the non-interposing position indicated by the dotted lines I88 in Figure 7. On the other hand, if the baiile I2 is in the interposing position shown by the full lines of that figure, the refrigerant liquid from the tube portion 54 will run down the inclined trough I2 of the baiile through a tube 8 into a chamber H2. The chamber I I2 is of smaller volume than the chamber I86 and is so arranged with respect to the latter that when the chamber H2 is filled with refrigerant liquid, additional liquid directed to it by the baffle I2 will overflow the chamber I I2 and flow along the bottom of the casing I6, through the tube I84, and into the chamber I86. The chamber H2 is located near the outer wall surface of the cabinet I3I to accelerate the evaporation of the liquid from chamber 2.

The volume of the chambers I86 and H2, the quantity of refrigerant liquid in the secondary system, and the height of the elevated portions I I6'of the siphon tube I I4 are so interrelated that when the chamber H2 and the tube H8 are filled with refrigerant liquid, the remaining refrigerant liquid, if contained in the chamber I86, will be of insufficient height. therein to start the flow of the liquid through the elevated portion I I6 of the This condition is shown by the solid liquid lines in Figure 6. n the other hand, when the chamber H2 is empty and substantially all of the refrigerant liquid is in the chamber I86, the height of the liquid therein will be as shown by the dotted line I I8 and the liquid will initiate the siphon action of the tube H4. The liquid'in the chamber I86 will thereupon run down the siphon tube I I4 to the evaporative portion I36 of the tube I28 until the chamber I86 is substantially empty. This will supply a large quantity of refrigerant liquid to the evaporative portion I36 in a short period of time so that the system can function with full effectiveness.

The refrigerant liquid will vaporize in the evaporative portion I36, condense in the conden- 5 sive portion 48, and flow into the casing I6 through the tube portion 64. If the lower compartment 28 is not cooled to the temperature at which the bellows 96 returns the ballle I2 to the full line position shown in Figure 5, the chamber I86 will be filled a second time to the height of the dotted line H8 and a second emptying of the liquid refrigerant content of the chamber I86 into the evaporative portion I36 will take place. This will be repeated a sufflcient number of times until the temperature ofthe lower compartment 28 has been reduced to the desired temperature. At this point, contraction of the bellows 86 allows the ballle 12 to return to the position shown by the full lines in Figure 4.

It will thus be seen that in this modification of the invention only the refrigerant liquid in the chamber I I2 is vaporized so that the refrigerant cycle can operate at full effectiveness in a short period of time.

It will be apparent from the above that this invention provides a means for regulating the temperature of a compartment cooled by a secondary volatile refrigerantcircuit.

While I have shown my invention in several forms, it will'be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What I claim is:

--1. A secondary volatile refrigerating system of the type having substantially the same pressure throughout, said system comprising, in combination, an evaporator adapted to cool a chamber, a vessel adapted to vaporize refrigerant liquid 40 therein at a slower rate than said evaporator, a

condenser adapted to condense the refrigerant vapor generated by said evaporator and said vessel, means for conducting the refrigerant liquid formed by said condenser selectively to either 5 said evaporator or said vessel, said means including a bellows subjected on one side to the pressure of a volatile fluid responsive to the temperature of said chamber and on the other side to the pressure of the volatile refrigerant in said system, and meansfor compensating for the effect of changes in pressure of said volatile refrigerant on said bellows.

2. In a refrigerator comprising an insulated cabinet, a partition therein dividing said cabinet 5 into an upper and a lower food storage chamber, a primary cooling unit for cooling the upper chamber, a volatile refrigerant circuit having a condenser. in heat transfer relationship with said cooling unit and an evaporator in heat transfer so relationship with said lower chamber, said circuit including a vessel, said condenser being arranged to discharge the condensed refrigerant through a tube into said vessel, a conduit having an entrance opening in said vessel below the exit 5 opening of said tube and above the bottom wall of said vessel, said conduit directing liquid into said evaporator, said vessel being of sufficient capacity below said entranceopening to contain all of the liquidrefrigerant condensable by said condenser from the charge of refrigerant in said circuit, the combination with said circuit of a baflle movable from a position whereby the liquid discharged by said tube flows mainly into said conduit to a position whereby said liquid flows mainly into said vessel, and means responsive to ber, a primary cooling unit for cooling the upper chamber, a volatile refrigerant circuit having a condenser in heat transfer relationship with said cooling unit and an evaporator in heat transfer relationship with said lower chamber, said circuit including a vessel, said condenser being arranged to discharge the condensed refrigerant through a tube into said vessel, a conduit having an entrance opening in said vessel below the exit opening of said tube and above the bottom wall of said vessel, said conduit directing liquid into said evaporator, said vessel being of sufiicient capacity below said entrance opening to contain all of the liquid refrigerant condensable by said condenser from the charge of refrigerant in said circuit, the combination with said circuit of a baflie movable from a position whereby the liquid discharged by said tube fiows mainly into said conduit to a position whereby said liquid fiows mainly into said vessel and to positions intermediate said two positions whereby said liquid flows in different proportions into said conduit and into i said vessel, and means responsive to the temperature of said lower chamber for moving said baflle to any of said positions.

6. A secondary volatile refrigerating system of the type having substantially the same pressure throughout, said system comprising, in combination, an evaporator adapted to vaporize refrigerant liquid by the absorption of heat, a, first chamber and asecond chamber, said first chamber being adapted to vaporize refrigerant liquid but at a slower rate than said evaporator, a condenser adapted toreceive and condense refrigerant vapor generated by said evaporator and by said first chamber, a siphon tube communicating with a lower portion of said second chamber to conduct a quantity 'of refrigerant liquid from said second chamber to said evaporator by siphon action when the refrigerant liquid'in said second chamber exceeds a predetermined height, said first chamber being so disposed with respect to said second chamber that when said first chamber is filled with refrigerant liquid, further refrigerant liquid supplied to it overflows to said second chamber, and means for conducting refrigerant liquid condensed by said condenser selectively to either said first or said second chamber, the volume of said first and second chambers being such that when a specific quantity of volatile refrigerant liquid is disposed in said system and the system is in normal operation the refrigerant liqud in said second chamber cannot exceed said predetermined height when said first chamber is full and does exceed said predetermined height when said first chamber is empty.

7. The refrigerating apparatus defined in claim 6 wherein said means consists of a movable bafile.

8. The refrigerant system defined in claim 6 including a space cooled by said evaporator and a thermostatic element responsive to the temperatureof said space and associated with said selective conducting means to cause said means to conduct the refrigerant liquid to saidv first chamber when the temperature of said space is above a predetermined temperature and to conduct the refrigerant liquid to said second chamber when said space is below a predetermined temperature.

9. The refrigerating apparatus defined in claim 8 wherein said means consists of a movable baflle.

10. A secondary volatile refrigerating system of the type having substantially the same pressure throughout, said system comprising, in combination, a quantity of volatile refrigerant liquid, an evaporator adapted to vaporize said refrigerant liquid by the absorption of heat, a first chamber and a second chamber, said first chamber being adapted to vaporize refrigerant liquid but at a slower rate than said evaporator, a condenser adapted to receive and condense refrigerant vapor generated by said evaporator and by said first chamber, a siphon tube communicating with a lower portion of said second chamber to conduct a quantity of refrigerant liquid from said second chamber to said evaporator by siphon action when the refrigerant liquid in said second chamber exceeds a predetermined height, said first chamber being so disposed with respect to said second chamber that when said first chamber is filled with refrigerant liquid, further liquid supplied to it overflows into said second chamber, and means for conducting the refrigerant liquid condensed by said condenser selectively to either said first or said second chamber, .the quantity of liquid refrigerant in said system when in normal operation and the volume of said first chamber being so proportioned, that when said first chamber is full, the refrigerant liquid in said second chamber cannot exceed said predetermined height, and when said first chamber is empty, the refrigerant liquid in said second chamber will exceed said predetermined height.

11. The refrigerating apparatus defined in claim 10 wherein said means consists of a movable baflle. I v

12. The refrigerant system defined in claim 10 including a space cooled by said evaporator and a thermostatic element responsive to the temperature of said space and associated with said selective conducting means to cause said means to conduct the refrigerant liquid to said first chamber when'the temperature of said space is above a predetermined temperature and to conduct the refrigerant liquid to said second,

chamber when said space is below. a predetermined temperature.

13. The refrigerating apparatus defined in claim 12 wherein said means consists of a movable baflle. Y

14. A secondary volatile refrigerating system of the type having substantially the same pressure throughout, said system comprising, in combination, an evaporator adapted to vaporize refrigerant liquid by the absorption of heat, a

vessel adapted to vaporize refrigerant liquid at a slower rate than. said evaporator, a condenser adapted to condense the refrigerant vapor generated by said evaporator and said vessel, conduit means for conducting the refrigerant liquid condensed by said condenser to said evaporator, said conduit means including a vertical portion having a gap therein through which said liquid drops, and a baflie adapted for movement into and out of said gap, said banle being formed to deflect the refrigerant liquid flowing from said condenser into said gap to said vessel when said bailie is moved into said gap.

15. The refrigerating ,system defined in claim 14 including a quantity of volatile liquid refrigerant in said system not in excess of the'capacity of said vessel.

16. The refrigerating system defined in claim 14 including actuating means responsive to heat for effecting the movements of said bafiie.

17. The refrigerating system defined 'in claim 14 wherein said system includes a chamber enclosing said baflle, magnetic material associated with said baflle to move the same, said magnetic material being located within said chamber, magnetic material located outside of said chamber and adapted to move the magnetic material located within said chamber, and means responsive to heat for moving the magnetic material located outsidev said chamber.

18. Refrigerating apparatus comprising, in combination, a primary refrigerating system of the compressor-condenser-evaporator type, said primary system having a tube for conducting liquid refrigerant from the condenser to the evaporator, and a secondary volatile refrigerating system having substantially the same pressure throughout, said secondary system comprising a secondary evaporator adapted to vaporize refrigerant liquid by the absorption of heat, a secondary condenser in heat-transfer relation with the evaporator of said primary system, a vessel adapted to trap refrigerant liquid, said vessel being in heat-transfer relation with said tube, and a movable baflie for conducting liquid refrigerant from said condenser selectively to either said secondary evaporator or said vessel.

RAYMOND E. TOBEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Alsing Dec. 23, 1947