US2426578A - Refrigeration apparatus including defrosting means - Google Patents

Description

s- 1947- R. E, TOBEY 2,426,578

REFRIGERATION APPARATUS INCLUDING DEFROSTING MEANS Filed Nov. 5, 194:5 2 sheets-sheet 2 ..FIG.2

INVENTOR Reyna/10%: Toqy BY ATTOREEY PM M ze, 1941, A,

REFRIGERATION APPARATUS INCLUDING DEEBOSTING MEANS Raymond E, Tobey, Springfield, Mass., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 5, 194:, Serial No. 509,058

This invention'relates to refrigeration apparatus and more particularly to a means for defrosting an evaporator. n

It is an object of the invention to .provide novel means for regulating the refrigeration of an evaporator, I

Another object of the invention is to provide novel means -for rendering one evaporator of a plurality of evaporators supplied by a common refrigerant supplying apparatus inactive without interfering with the refrigeration or the other evaporators;

A further object of the invention is to stop the flow. of liquid refrigerant toan evaporator of a plurality of evaporators, forming a part of a hermetically-sealed system, without introducing valves into the system and without affecting the flow of liquid refrigerant to the remainder of the evaporators.

o A still, further object of the invention is to provide means which permit defrosting of one evaporator of a plurality of evaporators served by common refrigerant circulation apparatus without affecting the operation of the remaining evaporators.

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

F g. l is a sectional view of a mechanical refrigerator embodying the invention and showing a schematic arrangement of the refrigerant passages and the electric wiring. The .view is taken on line II of Fig. 2;

Fig. 2 is a view of the food storage compartment of the refrigerator of Fig. 1 with the doors of the food storage compartment and the frozen.

food compartment removed, and the refrigerant passages shown schematically; and. r

Fig. 3 is a view, with parts broken away. of the refrigerant regulating chamber of this invention with the regulating cylinder in the lower position. a

Fig. 4 is a vertical sectional view of the refrigerant regulating chamber with the regulating cylinder in the upper position.

Referring now to the drawings for a detail description of the invention, the reference numeral l6 designates a refrigerator cabinet having an for driving the same.

. 2 located in the lower portion of the food storage compartment l2. 7 N

The food storage compartment comprises an inner metal liner l8 and an outer metal shell 26 spaced from the inner liner l8. The inner liner [6 is coated on the inner and outer sides with vitreous enamel. Thermal insulating material 22 is positioned between the metal liner II and the metal shell- 20. The food storage compartment I2 is provided with an access opening and a door 24 for closing the same. A separate door "is provided for the frozen food receptacle l6.

The food storage compartment i2 is maintained at an average temperature of about 40 F. by a refrigerant carrying tube 26 secured to the metal liner is. The tube 26 is shown located on the inner side of the metal linerl8 for the sake of clearness. In actual practice, it is located on the outer side thereof embedded in the thermal insulation 22. The frozen food receptacle I6 is maintained at an average temperature of about 25 'F. by a second refrigerant carrying tube 28 which is coiled around and brazed to the receptacle l6. The tubes 26 and 28 are connected in series and a suction tube 36 is connected to one end of the tube 28 to withdraw refrigerant vapor therefrom.

The tube 30 conducts the refrigerant vapor to a hermetically-sealed refrigerant liquefying apparatus, comprising a sealed casing 32 which contains a refrigerant compressor and a motor The compressor and the motor are not shown in the drawings. The compressed refrigerant vapor passes through a tube 34 to a refrigerant condenser 36, wherein the refrigerant vapor is cooled and condensed into a liquid. The condenser 36 is cooled by a current of air drawn therethrough by a motor-driven fan 38.

A chamber 42, forming a part of thisinvention, is located in the thermal insulating material 22 of the rear wall of the food storage compartment l2. The chamber 42 is formed of brass or other non magnetic material. The liquid refrigerant is conducted by a capillary tube 46 from the condenser 36 to the upper portion of the chamber insulated food storage compartment. II in the upper portion and a machine compartment It in g the lower portion of the cabinet. The food storage compartment l2 is'provided with a drain tube 15. A metal receptacle ii for frozen foods is 42. The capillary tube 40- aflords such impedance to the flow of refrigerant that substantially no liquid refrigerant is retained inthe condenser 36 during normal operation. The chamber 42 has an opening 44 approximately midway between its top and bottom, and a tube 46 communicates with the' opening 44 to conduct the refrigerant liquid flowing from said opening 44 to the tube 26. The chamber 42 is continuously filled with refrigerant liquid to the level of the opening 44 and with refrigerant vapor above said opening. The refrigerant liquid in the chamber 42 is comparatively inactive because the thermal insulation surrounding the chamber 42 prevents heat from being conducted to the liquid and vaporizing it.

A cylinder 48 of iron or other magnetic material is located in the chamber 42 and normally occupies substantially all of the portion of the chamber lying below the level of the opening IL- An electric winding II is placed around the upper portion of the chamber 42 and when energized raises the cylinder 48 and retains it in the upper portion of the chamber 42. The chamber 42, thereupon, will fill up with refrigerant liquid to the level of opening 44: Theelectric winding ill on the chamber 42 is energized from sup- I ply lines 52 and 54 through leads 58 and 58. A switch 60 is located in series in the lead 56.

The temperature of the food storage compartment I2 is controlled by atheimostat 64 comprising a bulb 88 containing a volatile refrigerant liquid. The bulb 68 is in thermal contact with the metal liner II and connects with a Sylphon bellows 88 through a tube 1'0. The Sylphonbellowsfl opens and closes a switch 12 located in a lead 14 which together with lead 16 supplies electrical energy from the supply lines 52 and 54 to the compressor located in the hous-- ing 32. The temperature of the food storage form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire,

' therefore, that only such limitations shall be from said compressor, a tube connected to concompartment I! will thus be maintained substantially constant regardless of the position of the cylinder 48.

Operation During normal operation, the switch 60 is open duct refrigerant liquid from said condenser to said first evaporator, a thermostatic control for said compressor to maintain said first chamber at an above-freezing temperature, and means for providing the effect of selectively varying the refrigerant charge -of the refrigerator to the extent of supplying liquid refrigerant either sufficlent for both of said evaporators or sufficient for qnly said first evaporator, said second evaporator and second chamber being in such heat-transfer relation and the suction of said compressor being' such that said second chamber is maintained at below-freezing temperatures when said refrigerant charge is sufllcient for both evaporators.

" 2. A refrigerator comprising first and second evaporators connected in series, first and second and the refrigerating apparatus supplies both the tubes 26 and 20 with refrigerant liquid, and only the tube 28 and frozen food recept'acle It will accumulate frost. If it is desired to defrost the frozen food receptacle IS, the switch 60 is closed. This energizes the winding 50 on the chamber 42 and elevates the cylinder 48. Refrigerant liquid of the system will then accumulate in the chamber 42 to the level of opening 44, and the chamber 42 thereby abstracts a quantity of refrigerant -liquid from the system and renders the abstracted liquid inactive. The active refrigerant liquid remaining in the system is sufil cient to refrigerate only the food storage compartment I! because the refrigerant liquid is completely vaporized in the tube zfi'so that only refrigerant vapor passes through the tube 28. The vapor, however, is at the temperature prevailing in the tube 26 and furthermore does not have the heat absorbing capacity of the refrigerant liquid. The frozen food receptacle It will, thereupon, increase in temperature to that of the food storage compartment l2, the frost on the frozen food receptacle 8 will melt, and the defrost water will fiow out through the drain tube l5.

It will be apparent from the above that this invention provides apparatus for defrosting one evaporator of a plurality of evaporators supplied by a common refrigerant supplying apparatus. The invention also provides a means for varying the amount of effective refrigerant in a closed refrigerating system. It will be further apparent that the apparatus of this invention does not introduce valves into a hermetically-sealed refrigstorage chambers in heat-transfer relation with said first and second evaporators respectively, a compressor for withdrawing refrigerant vapor, the suction side of said compressor being connected to said second evaporator at a point remote from the connection of said second evaporator to said first evaporator, a condenser receiving compressed refrigerant vapor from said compressor, a tube connected to conduct refrigerant liquid from said condenser to said first evaporator, thermostatic means controlling said compressor to maintain said first chamber at an above-freezing temperature, the suction of said compressor beingof such degree and the heat-transfer relation between said second evaporator and said second chamber being so much more effective than the heat-transfer relation between said first evaporator and said first chamher as to cause said second chamber to be maintained at a below-freezing temperature when said first chamber is maintained at said above-' freezing temperature and said first and second evaporators are supplied with liquid refrigerant by said condenser and tube, and means for providing' the effect of selectively varying the refrigerant charge of the refrigerator to the extent of supplying liquid refrigerant either suflicient for both of said evaporators or sufficient for only said first evaporator.

RAYMOND E. TOBEY.

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

UNITED STATES PATENTS Number 2,133,952- Buchanan a Oct. 25,- 1938

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