US3057169A

US3057169A - Refrigerating apparatus with defrost means

Info

Publication number: US3057169A
Application number: US98162A
Authority: US
Inventors: James W Jacobs
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1961-03-24
Filing date: 1961-03-24
Publication date: 1962-10-09
Anticipated expiration: 1979-10-09

Description

Oct. 9, 1962 J. w. JACOBS 3,057,159

REFRIGERATING APPARATUS WITH DEFROSTMEANS Filed March 24, 1961 I l l IN VENTOR.

James M Jacobs United States Patent Office 3,057,159 Patented Oct. 9, 1962 3,057,169 REFRIGERATIN G APPARATUS WITH DEFROST MEANS James W. Jacobs, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Mar. 24, 1961, Ser. No. 98,162 12 Claims. (Cl. 62-154) This invention relates to refrigerating apparatus and more particularly to an improved refrigerant circuit and an improved control for the circuit.

It is an object of this invention to provide an improved refrigerant circuit wherein it is only necessary to make one opening into the refrigerant condenser.

Another object of this invention is to provide an improved arrangement for defrosting a refrigerant evaporator.

More particularly, it is an object of this invention to provide an improved type of magnetically operated valve arrangement for disconnecting the liquid line from the evaporator and for supplying relatively hot refrigerant from the condenser to the evaporator for defrosting the evaporator.

Still another object of this invention is to provide an improved refrigerating system wherein a capillary tube type of restrictor has its outlet end arranged to be movable into and out of direct fluid flow relationship with the inlet of the evaporator.

These and further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

FIGURE 1 is a schematic view showing the refrigerant circuit and the electrical controls for the same.

FIGURE 2 is a fragmentary sectional view on an enlarged scale showing the control for the outlet of the capillary tube restrictor.

FIGURE 3 is a sectional view taken substantially on line 3-3 of FIGURE 2.

Referring now to the drawing wherein a preferred embodiment of the invention has been shown, the refrigerating system includes a conventional motor compressor unit it a condenser 12, a receiver 14, a capillary tube type restrictor 16 for supplying liquid refrigerant from the receiver 14 to the evaporator 18 located in a food storage compartment 40. The vaporized refrigerant leaving the evaporator 18 is compressed by the compressor 18 in the usual manner and the refrigerant thus compressed fiows through an outlet line 21) which joins with the line 22 leading from the condenser 12 to the evaporator 18.

During normal operation of the refrigerating system, the compressed refrigerant flowing in the line 20 is directed into the condenser 12 but in the event that it is desired to defrost the evaporator 13, the compressed refrigerant is allowed to flow directly into the evaporator 18, in a manner to be described hereinafter. It will be noted that the capillary tube restrictor 16 has its inlet end arranged in the receiver 14 and has its outlet end terminating in a reciprocating valve-like member 24 arranged at the inlet to the evaporator 18. The valvelike member 24 normally seats against an apertured resilient bushing 26, as shown in FIGURE 2 of the drawing so as to prevent compressed refrigerant gas in the line 22 from entering the evaporator directly.

When the element 24 is seated against the element 26, the liquid refrigerant leaving the outlet end of the capillary tub 16 is fed directly into the evaporator 18.

When it is desired to defrost the evaporator 18, a solenoid coil 28 is energized and this serves to pull the valve member 24 downwardly, as viewed in FIGURE 2, so as to unseat this member from the bushing 26. The member 24 is of magnetic material and is provided with a plurality of axially extending grooves or fluid passages 27 in its outer periphery whereby the high pressure refrigerant in the condenser is free to flow into the evaporator whenever the solenoid 28 is energized.

When the element 24 is pulled away from the bushing 26, it is obvious that both ends of the capillary tube will be subjected to substantially the same pressure with the result that little, if any, refrigerant flow will take place in the capillary tube 16 and the main flow of refrigerant will be in the space between the capillary tube and the inner walls of the line 22 and through the passages 27. After the evaporator has been fully defrosted, the solenoid 28 will be deenergized and when this takes place, the element 24 will reseat against the bushing 26. It will be noted that the outlet end of the capillary tube is provided with a plurality of convolutions 30, which, in eifect, form a coil spring for biasing the member 24 into seating engagement with the bushing 26. A separate coil spring (not shown) could be provided, if desired, for biasing the element against the seat on the bushing 26.

For purposes of illustration, there is shown a control for the solenoid 28 which operates in the following maner. During normal operation of the apparatus thus far described, the food in the food storage compartment 40 is maintained at a temperature of approximately 36 F. for the purpose of preserving unfrozen foods. A thermostat 41 located on the evaporator 18 normally cycles the motor compressor unit 10 through the switch 42 by opening the switch when the temperature at the thermostat 41 falls below 18 F. and by reclosing the switch when the temperature at the thermostat 41 exceeds 24 F.

Frost tends to accumulate on the evaporator 18 and the amount which does accumulate is determined to a large extent by the amount of produce placed within the refrigerator and the frequency at which the doors to the food compartment are opened. The above factors also determine to a large extent the portion of the time during which the motor compressor unit 10 is required to operate and, consequently, the timer which has been provided for timing the defrost cycle of the frozen food compartment is so connected in the circuit that it will only count the time during which the motor compressor uni-t 10 operates. Thus, the timer motor 50 includes a field winding 52 which is arranged as shown in series with the switch 52 across the main power supply line 53. The timer motor 50 is provided with a driven cam 54 which serves to actuate a switch operating plunger 56, as shown. The plunger 56 is adapted to ride on the cam 54 as shown and does not close any circuits until the cam follower 56 rides up onto the cam surface 58, at which time, a circuit is closed at the contacts 60. Closing of the circuit through the contacts 60 short-circuits the thermostatic operated switch 42 whereby the motor compressor unit 10 will serve to operate even though the theromstat 41 may indicate that no refrigeration is required. The purpose of this is to build up the head pressure in the condenser 12 just prior to the defrosting of the evaporator 18. The cam 54 is provided with a second raised portion 62 which subsequently serves to raise the cam follower high enough to close the circuit through the contacts 64. When the contacts 64 are closed, current is fed to the valve controlling solenoid 28 so as to cause the element 24 to move downwardly, as viewed in FIGURE 2. Upon energization of the solenoid 28 and downward movement of the valve 24,

hot uncondensed refrigerant -vapor contained in the condenser and the lines connected to the outlet of the motor compressor unit is free to flow upwardly past the valve element 24 into the evaporator 18. The condensed liquid in the condenser 12 goes through a phase change because of the sudden lowering of the vapor pressure upon it. Thus, the liquid in the condenser boils and the condenser 12 becomes a high temperature evaporator. The vapor in the condenser then passes up the line 22 surrounding the restrictor 16 into the evaporator 18. The quantity of vapor which is fed through the line 22 into the evaporator 18 for defrost purposes is in excess of that actually required to defrost the evaporator whereby the refrigerant vapor which has been condensed in the evaporator 18 during the defrost cycles is reevaporated by such excess refrigerant prior to its return to the compressor, with the results that no slugs of refrigerant enter the compressor.

Insofar as certain aspects of this invention are concerned, other types of control systems could be used for controlling the solenoid 28. Likewise, the refrigeration system can be used in a wide variety of refrigerators and only the simplest form of refrigerator has been shown for purposes of illustrating the invention.

7 While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a refrigerating system, the combination, a compressor, a condenser, an evaporator, a receiver connected to the outlet of said condenser, means for connecting the outlet of said evaporator to the inlet of said compressor,'--means for directing hot compressed refrigerant gas from-the outlet of said compressor to the inlet of said condenser, a first conduit supplying liquefied refrigerant from said receiver to the inlet of said evaporator, means including a second conduit surrounding the outlet end of said first conduit for supplying hot refrigerant gas from-said condenser to the inlet of said evaporator.

2. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship Withsaid compressor and said condenser, said refrigerant flow means including conduit means for selectively connecting the outlet of said compressor to the inlet of said condenser or to the inlet of said evaporator, said refrigerant flow means including a capillary tube concentric with at least a portion of said conduit means for connecting said condenser to the inlet of said evaporator, said refrigerant fiow means including means for lay-passing said capillary tube when the outlet of said compressor is connected to the inlet of said evaporator.

3. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including conduit means for selectively connecting the outlet of said compressor to the inlet of said condenser or to the inlet of said evaporator, said refrigerant flow means including a capillary tube concentric with at least a portion of said conduit means for connecting said condenser to the inlet of said evaporator, a valve port element disposed in said conduit means-adjacent the inlet to said evaporator and arranged to be engaged by the outlet end of said capillary tube so as to seal off said conduit means from said evaporator, and means for moving the outlet end of said capillary tube out of engagement with said valve port element so as to permit flow of refrigerant from said conduit means into said evaporator.

4. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including conduit means for selectively connecting the outlet of said compressor to the inlet of said condenser or to the inlet of said evaporator, said refrigerant flow means including a capillary tube concentric with at least a portion of said conduit means for connecting said condenser to the inlet of said evaporator, a valve port element disposed in said conduit means adjacent the inlet to said evaporator and arranged to be engaged by the outlet end of said capillary tube so as to seal off said conduit means from said evaporator, means for moving the outlet end of said capillary tube out of engagement with said valve port element so as to permit flow of refrigerant from said conduit means into said evaporator, a solenoid coil adjacent said outlet end of said capillary tube, and an armature secured to said outlet end for actuating said end in response to energization of said solenoid coil.

5. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including conduit means for selectively connecting the outlet of said compressor to the inlet of said condenser or to the inlet of said evaporator, said refrigerant flow means including a capillary tube concen- 9 trio with at least a portion of said conduit means for connecting said condenser to the inlet of said evaporator, a valve port element disposed in said conduit means adjacent the inlet to said evaporator and arranged to be engaged by the outlet end of said capillary tube so as to seal off said conduit means from said evaporator, means for moving the outlet end of said capillary tube out of engagement with said valve port element so as to permit flow of refrigerant from said conduit means into said evaporator, a solenoid coil adjacent said outlet end of said capillary tube, and an armature secured to said outlet end for actuating said end in response to energization of said solenoid coil, said armature having longitudinally extending fluid passages formed therein through which refrigerant flows when said solenoid coil is energized.

6. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including conduit means for selectively connecting the outlet of said compressor to the inlet of said condenser or to the inlet of said evaporator, said refrigerant flow means including a capillary tube conduit means for connecting said condenser to the inlet of said evaporator, a valve port element disposed in said conduit means adjacent the inlet to said evaporator and arranged to be engaged by the outlet end of said capillary tube so as to seal off said conduit means from said evaporator, means for moving the outlet end of said capillary tube out of engagement with said valve port element so as to permit flow of refrigerant from said conduit means into said evaporator, a solenoid coil adjacent said outlet end of said capillary tube, and an armature secured to said outlet end for actuating said end in response to energization of said solenoid coil, said capillary tube comprising a coiled intermediate portion forming a spring means for biasing the outlet end of said capillary tube into engagement with said valve port.

7. Refrigerating apparatus comprising in combination, a refrigerant compressor, a condenser, an evaporator, a capillary tube type restrictor having its outlet end movable into and out of engagement with the inlet to said evaporator, means for connecting said compressor, condenser, restrictor and evaporator in series refrigerant flow relationship, a thermostatic cycling control means for starting and stopping the operation of said compressor at relatively frequent intervals, means for supplying compressed refrigerant to said evaporator at defrosting temperatures so as to defrost said evaporator, and means for controlling the supply of said compressed refrigerant to said evaporator so as to cause defrosting thereof at relatively less frequent intervals, said last named means comprising means for actuating the outlet end of said capillary tube into and out of engagement With the inlet of said evaporator.

8. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means conmeeting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including conduit means connecting the outlet of said compressor to the inlet of said condenser and to the inlet of said evaporator, a capillary tube connecting the outlet of said condenser to the inlet of said evaporator, said capillary tube having its outlet terminating adjacent the inlet of said evaporator, the inlet to said evaporator having a valve seat formed therein, said tube having a movable valve portion secured to its outlet end and cooperating with said seat to prevent the flow of refrigerant from said conduit means into said evaporator in one position of valve portion.

9. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including conduit means connecting the outlet of said compressor to the inlet of said condenser and to the inlet of said evaporator, a capillary tube connecting the outlet of said condenser to the inlet of said evaporator, said capillary tube having its outlet terminating adjacent the inlet of said evaporator, the inlet to said evaporator having a valve seat formed therein, said tube having a movable valve portion secured to its outlet end and cooperating with said seat to prevent the flow of refrigerant from said conduit means into said evaporator in one position of valve portion, and magnetic means for actuating said movable valve portion.

10. Refrigerating apparatus comprising in combination, a refrigerant liquefying means including a condenser, an evaporator, a capillary tube restrictor supplying refrigerant from said condenser to the inlet of said evaporator, means for returning evaporated refrigerant from said evaporator to said liquefying means, a thermostatic cycling control means for starting and stopping the operation of said liquefying means at relatively frequent intervals, and means for supplying compressed refrigerant to said evaporator at defrosting temperatures so as to defrost said evaporator at less frequent intervals, and means for controlling the supply of said refrigerant to said evaporator including means for moving a portion of said restrictor so as to control the flow of refrigerant to said evaporator.

11. Refrigerating apparatus comprising in combination, a refrigerant liquefying means including a condenser, and evaporator, a restrictor tube supplying liquid refrigerant from said condenser to the inlet of said evaporator, means for returning evaporated refrigerant from said evaporator to said liquefying means, a thermostatic cycling means for starting and stopping the operation of said liquefying means at relatively frequent intervals, and control means for supplying compressed refrigerant to said evaporator at defrosting temperatures so as to defrost said evaporator at relatively infrequent nitervals, said control means having means for preventing the stopping of said liquefying means immediately preceding the defrosting of said evaporator, said means for controlling the supply of said compressed refrigerant to said evaporator including means for moving the outlet of said restrictor tube out of engagement with the inlet to said evaporator.

12. In a refrigerator, a cabinet having a food storage compartment therein, an evaporator in said compartment, a compressor, a condenser, refrigerant flow means connecting said evaporator in refrigerant flow relationship with said compressor and said condenser, said refrigerant flow means including first conduit means connecting the outlet of said compressor to the inlet of said condenser and to the inlet of said evaporator, and a capillary restrictor concentric With at least a portion of said conduit means for supplying liquid refrigerant from said condenser to the inlet of said evaporator, said re strictor comprising a capillary tube terminating adjacent the inlet of said evaporator, the inlet to said evaporator having a valve seat formed therein, said tube having a movable valve portion cooperating with said seat to prevent the flow of refrigerant from said conduit means into said evaporator in one position of said valve portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,145,774 Mufily Jan. 31, 1939 2,785,542 Thomas Mar. 19, 1957 2,888,808 Jacobs June 2, 1959 2,959,027 Ewing Nov. 8, 1960