US2966042A - Refrigeration system - Google Patents

Description

Dec. 27, 19 60 c. E. DE TURK REFRIGERATION SYSTEM 2 Sheets-Sheet 1 Filed April 8, 1957 INVENTOR. (/IZV/A E. 05 Tl/XK Amwr Dec. 27, 1960 c. E. DE TURK 2,966,042

REFRIGERATION SYSTEM Filed April 8, 1957 2 Sheets-Sheet? F/q. 7: gamw ascents Patented Dec. 27, 1960 ice REFRIGERATION SYSTEM Calvin E. De Turk, Drexel Hill, Pa., assignor to Philco Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Apr. 8, 1957, Ser. No. 651,449

Claims. (Cl. 62-156) The present invention relates to refrigeration apparatus and, more particularly, to domestic refrigerators of the type having evaporator means adapted to freeze food and water as well as to maintain such food and water at freezing temperatures, and which evaporator means is further adapted to be heated, at desired or predetermined intervals, to effect removal of frost therefrom.

With a refrigerator of the above-mentioned variety, it has been known to support food, which has been previously frozen, by means serving to prevent undue rise of the temperature of the supported food during heating of the evaporator to defrost the same. However, in the initial freezing and subsequent storage of ice, and also of certain food materials, by use of conventional receptacles or ice trays, it has been the practice to establish optimum thermal contact of such trays with the evaporator in order to ensure more rapid freezing of the contents thereof. Ice, for example, thus stored is of course unharmed by partial melting of the same, as often occurs during the defrost period. It is known, however, that loaded trays represent a considerable thermal mass, which in contact with the evaporator means while defrosting, effects a substantial increase in the time required for defrosting. This excessive time is objectionable in that it contributes to undue warm-up of frozen food while defrosting takes place.

It is therefore an important objective of the invention to provide novel means for overcoming the above noted objection.

In accordance with the general features of the invention, there is provided means in association with a defrostable cooling element, and operable to provide substantially less than optimum heat exchange relation be tween a receptacle and such element while defrosting the latter.

In the achievement of the foregoing and other objec tives a preferred embodiment of the invention comprises means which, during normal refrigerating operation, provides direct contact of ice trays with the evaporator, said means being operable with the defrosting means to break the ice bond between said trays and said evaporator and to move the trays substantially out of contact with the evaporator, thereby effectively lessening the heat required for defrosting and minimizing, accordingly, the degree of warm-up of foods refrigerated by the evaporator.

The novel features of the invention, and the manner in which the foregoing and other objectives and advantages are best achieved, will be apparent from the following description taken in view of the accompanying drawings in which:

Figure 1 is a perspective view of a refrigerator embodying the invention;

Figure 2 is a view, on a somewhat enlarged scale, of a portion of the refrigerator shown in Figure 1, with parts broken away;

Figure 3 is a somewhat diagrammatic elevational view of apparatus shown in Figure 2;

Figure 4 is a view similar to Figure 3 and showing an operational feature of the invention;

Figure 5 is a diagrammatic showing of a refrigerating system embodying the invention;

Figure 6 is a fragmentary showing, similar to Figure 5, of an alternative embodiment of the invention;

Figure 7 is a fragmentary showing similar to Figure 5, of still another embodiment of the invention; and

Figure 8 is a fragmentary showing, similar to Figure 2, of an additional embodiment of the invention.

Now making more particular reference to the drawings, it will be seen in Figure 1 that the invention is embodied in a domestic or household refrigerator which comprises a cabinet 10 having an outer shell 11 and a pair of inner liners 12 and 13, said shell and liners being spaced and insulated from each other by means of suitable insulation 14 (see also Figure 2). As is customary, breaker strips 15 of low thermal conductivity extend about the forward edge of the cabinet and bridge the gaps between the shell and inner liners. These liners define two isolated zones which constitute a lower compartment 16 and an upper compartment 17. Insulated doors 18 and 19 of usual construction and including gasket strips 20, are, respectively, employed to close the front access opening of each of said compartments.

The lower compartment 16 is utilized for the storage of frozen food (not shown) and ice trays 24, as well as for the freezing of these articles. According to usual practice, compartment 16 is supplied with slidable drawers or racks 25 for supporting the food out of contact with conventional evaporator means provided in this compartment, said means including a suitable refrigerated shelf 26 provided with refrigerant conduit means 32 in heat exchange relation therewith and (see also Figure 5) adapted for the support of ice trays 24 both to be frozen and stored. The upper compartment 17 is effectively cooled and maintained at cooling or non-freezing temperatures by means of an evaporator 27, which in the illustrated embodiment, comprises a generally rectangular etallic sheet 28 provided with conduit means 29 for circulation of refrigerant in heat exchange relation with said sheet. The plate evaporator 27 is conveniently mounted in a vertical position close to the rear wall and spans substantially the width of the compartment as defined by, confronting side walls of said liner so as to present a comparatively large surface exposed to the air within said upper compartment.

No-w referring to Figure 2, and in particular accordance with a preferred embodiment of the present invention, the lower side of the evaporator ice freezing shelf 26 is provided with a horizontally disposed rotatable shaft 30 having spaced axially thereof a plurality of cam elements 34; rotatable support of the shaft is provided by suitable bracket means 31 afiixed to refrigerated shelf 26. Intermediate each supported tray 24, there being shown but one tray for illustrative purposes, and cam element 34 is an aperture 35 formed in ice freezing shelf 26. Portions of cam elements 34 are respectively extensible and retractable through apertures 35 operably to engage each tray 24, tiltably to raise or lower the same about evaporator contacting end portions of the trays as fulcrums, and in response to operation of the crank 36 provided at the end of rotatable shaft 30. Although the illustrated embodiments of the invention include apparatus for tilting the trays out of substantial thermal contact, it is to be understood that additional cam elements may be provided to raise the trays, and suspend the same, entirely out of contact with the evaporator or, in certain embodiments, the trays could be shifted laterally. Operation of crank 36 is accomplished through the agency of a bar 37 pivotally aflixed thereto, said bar being longitudinally actuatable by solenoid means 38, thereby to rotate shaft 30 and its camming elements 34 as described. Means in novel association with the aforesaid solenoid means 38, for energizing the same in response to initiation of the defrost cycle, will be hereinafter more fully explained.

As seen further in Figure 5, evaporator shelfzfiand the upper plate evaporator 27 form parts of an automatically defrostable refrigerating system which includes a motor compressor 39 and a condenser 40. Preferably, although not necessarily, the refrigerating system illustrated is made in accordance with that disclosed and claimed in U.S. patent to E. W. Zearfoss, No. 2,627,730, issued February 10, 1953, and assigned to the assignee of the present invention. On-and-ofi cycling of the motor compressor 39 is controlled by means of a device 44 of the known bellows type having a feeler tube 45 which may, for example, be arranged in heat exchange relation (not shown) with the plate evaporator 27 so that the temperature of the latter influences the operation of the device to actuate a switch element 46 for opening and closing contacts 47 in the electrical circuit, which is adapted to supply electrical energy to the motor compressor 39. Preferably, although not necessarily, the control device 44 is such that when the temperature of plate evaporator 27 reaches the lower end of its predetermined operating temperature range switch element 46 is moved to open the circuit to deenergize motor compressor 39, and when the temperature of the evaporator reaches the upper end of the range the switch element is actuated to close the circuit to energize the motor compressor.

Evrporators 26 and 27 are connected in series flow circuit by means of a conduit 48 which leads from the outlet of plate evaporator 27 to the inlet of evaporator 26. The outlet of evaporator 26 communicates through a conduit section with an accumulator 49 which, in turn, communicates with the inlet side of compressor 39 through a conduit section 50, and the outlet side of the compressor is connected with the inlet end of the condenser through a conduit 54. A capillary tube arrangement 55 serves to connect the outlet end of condenser 40 with an accumulator device 56, said device being further connected to the plate evaporator 27 by means of a suitable conduit 57. A by-pass connection or conduit 58 extends from the compressor discharge conduit 54 to the aforementioned accumulator device 56, and a solenoid actuated valve 59 in the by-pass connection 58 serves to open or close the same.

Inasmuch as operational details of the defrosting system illustrated are fully explained in the aforementioned Patent 2,627,730 no detailed description will be necessary. However, it is pointed out that the control circuit of the illustrated refrigerating system includes a single throw double pole switch 64, and the defrosting cycle is initiated in response to closure of this switch, by suitable manual or automatic means (not shown), regardless of the position of the contacts of the thermostatic switch device 44. Closing of the switch 64 places solenoid actuated valve means 59 across line L (Figure thereby energizing the same to open the valve and concurrently energizing the compressor 39 with and modifying flow of refrigerant within the system in such manner that defrosting of the evaporators take place.

In particular accordance with the invention the electrical solenoid means 38, hereinbefore referred to, is disposed in parallel circuitry with the solenoid of valve 59 in such manner that initiation of the defrost cycle through energization of solenoid valve 59 will energize the solenoid means 38, thereby retracting bar 37 and op erating crank 36. This operation of the crank rotates cams 34 through the openings 35 in ice freezing shelf or evaporator 26, whereby cams 34 operably engage end portions of the ice trays 24 resting upon the shelf, as best seen somewhat diagrammatically in Figures 3 and 4, to lift the trays out of substantial thermal contact with 4 a the evaporator. While lifting of the trays is sufficient to break the effective thermal contact, the movement is of such a nature as to prevent overflow or spilling of water onto evaporator surfaces.

Upon completion of the defrost cycle and opening the defrosting switch 64, solenoid valve 59 is deenergized, and the normal refrigerating cycle resumed. Concurrent with deenergization of the solenoid valve, the cam actuator solenoid 38 1s deenergized whereupon the vertical weight components of ice trays 24, or other suitable means, cause cams 34 to retract thereby again providing substantial thermal contact of the trays with the ice freezing shelf.

Alternatively, as illustrated in Figure 6, the cam actu ator solenoid 38 may be placed across the line L in series with a normally open bellows-actuated thermostatic switch 65 of known design having its feeler bulb 66 in thermal contact with, for example, the inlet conduit 57 of the evaporator system. In such an arrangement then mostatic switch 65 is so conditioned as to close, in response to a predetermined elevated temperature characteristic of the defrost cycle, thereby energizing the cam actuating solenoid 38 to elevate the trays in the manner hereinbefore described. .Return to normal operating temperatures following the defrost period will, of course, open the thermostatic switch, in accordance with a predetermined lower temperature limit, and deenergize the cam actuating solenoid to lower the trays into thermal contact with the evaporator.

An additional embodiment is seen in Figure 7 wherein apparatus of the type shown in Figure 6 has been somewhat modified by providing a direct mechanical linkage between a suitable pressure responsive expansiole and retractable bellows 67 and the tray release mechanism. Actuating pressure in the bellows 67 is determined by the sensing element or feeler bulb 66 in contact with conduit 57 in the refrigerator circuit. In operation, ele vated temperatures characteristic of the defrosting cycle will cause the bellows to expand thereby operating the cam linkage 34, 36, 37, to elevate the trays, in the manner hereinbefore described. Cessation of defrosting. characterized by reduced temperatures, will cause the bellows to contract thereby operating the cam linkage in the reverse direction to lower the trays into thermal contact with the evaporator.

Still another embodiment is shown in Figure 8, wherein the solenoid means has been disposed intermediate shell 11a, and liner 13a of the cabinet 19a, as indicated by reference character 38a. Individual cam links 34:: disposed within perforations or apertures 3551 provided in the evaporator shelf 26a are mounted for pivotal movement upon individual pins 3e11, the latter being supported within downwardly turned flange portions 35a of evaporator 26a. Operably connecting the cam links, as by pins 30b, to the operating solenoid is a connecting link 37b adapted for horizontal, substantially linear movement, whereby actuating the solenoid 38a with the defrosting means will rotate cam links 34:: to lift the trays (not shown). Conversely, deenergization of the solenoid will reverse the movement of the linkage and lower the trays.

While this description and the accompanying drawings are illustrative of preferred embodiments of the in vention, it will be recognized that additional changes and modifications may be made in the described apparatus, without departing from the spirit of the invention as defined in the appended claims.

I claim:

1. A refrigerator comprising: an evaporator adapted to refrigerate at temperatures below freezing and hav ing provision for supporting receptacles containing water or other material to be frozen; means for defrosting said evaporator by subjecting. the latter to heat at temperatures above freezing; control means operative to initiate defrost of said evaporator; and means operative with said control means upon initiation of the defrost to break the ice bond between said receptacles and said evaporator and to move said receptacles substantially out of contact with said evaporator.

2. In combination with automatically defrostable refrigerator evaporator means having a tray supported in contact therewith, a rotatable member disposed adjacent said tray, a cam element carried by said rotatable member in the region of said tray, said cam element being adapted operably to engage said tray and move the same in response to rotation of said rotatable member, control means operative to initiate defrosting of said evaporator means and means operative with said control means upon initiation of defrosting to actuate said rotatable member to move the tray.

3. In combination with a freezer compartment having a defrostable evaporator for maintaining below freezing temperatures in said compartment, said evaporator further being adapted to support a tray and having an aperture provided in the region of a supported tray, extensible and retractable cam means operable for movement through said aperture into and out of contact with a supported tray to, respectively, elevate and lower such a tray out of or into contact with the evaporator, control means operative to initiate and terminate defrosting of the evaporator, and means for operating the cam means actuatable by said control means to initiate or terminate defrosting of the evaporator, respectively, to raise or lower the trays.

4. In a refrigerator having cooling means presenting a defrostable refrigerating surface within said refrigerator, said surface being in high heat exchange relation with receptable means supported in contact therewith, means for defrosting said cooling means, control means operative to actuate said means for defrosting, and means operable by said control means, upon actuation of said means for defrosting, for supporting said receptacle means in relatively poor heat exchange relation with said refrigerating surface.

5. In a refrigerating system including a defrostable cooling element adapted to refrigerate a receptacle supported in contact therewith, control means operative to condition said cooling element for defrost, and means operative by said control means when the cooling element is conditioned for defrost to reduce the contacting area of a supported receptacle.

Anderson Sept. 13, 1955 Williams Feb. 21, 1956

Images