US2166506A - Refrigerating apparatus - Google Patents

Description

July 18, 1939. pHlLlPP 2,166,506

REFRIGERATING I'XPPARATUS Original Filed March 16, 1953 5 Sheets-Sheet 2 4c: Pmzzzwq PLATE IYUPMQL CYCLl/YQ ICE FREEZI/YQ F L 03 All? caou/rq PL/IT flair/0m. cvcunq ICE FREEZING INVENTOR /bg5 LHWREHCE fl. PHIL/PP 66) 618i Y M g M,

ATTORNEY.

5 Sheerls-Sheet 5 Original Filed March 16, 1933 RP v EM 0 V W mP 0.; m

Patented July; 18 19 39;

PATENT OFFICE REFRIGERATING APPARATUS Lawrence A. Philipp, Detroit, Mich., asslgnor to Nash-Kelvlnator Corporation, Detroit, Mich.,

a corporation of Maryland Original application March '16. 1933, Serial No.

Divided and this application July 10, 1937, Serial No. 153,012

7 Claims. .(Cl.-62-116) This invention-relates to refrigerating apparatus, and more particularly to refrigerating apparatus of the multiple temperature type.

The present application is. a division of my 5 copending application for Refrigerating apparatus, Serial No. 661,033 filed March 16, 1933, and which has now matured into Patent No. 2,095,010, dated Oct. 5, 1937.

One of the objects of my invention is to provide l0 a new and improved arrangement for freezing substances and for cooling circulating air in a refrigerator cabinet.

Another object of my invention is to provide an improved and simplified arrangement for obtaining a temperature differential between a number of different refrigerator evaporators.

Another object of my invention is to provide for maintaining a substantially constant temperature differential between a number of different refrigerant evaporators without the necessity of making adjustments although various average mean temperatures are sought to be attained in the different.

evaporators.

Another object of my invention is to provide an improved unitary refrigerating system in'a refrigerator cabinet, which system includes arefrigerant condensing element, a low temperature refrigerant evaporator for freezing large quantities of ice cubes and the like, and a relatively high 0 temperature refrigerant evaporator for cooling circulating air in the food compartment of the cabinet, and to provide for controlling the operation of the condensing element in response to changes in temperature in the relatively high tem- 35 perature evaporator, and also to provide an improved alrrangementfor maintaining a substantially constant temperature differential between said evaporators which permits a large quantity of substances to be frozen to be applied to the low 40 temperature evaporator without effecting the average temperatures maintained in the air cooling evaporator, while at the same time the operation of the condensing element continues until the heat of the substances to be frozen is substantially 5 or entirely absorbed by the low temperature evaporator. Another object of my invention is to provide within a refrigerator cabinet 'an improved arrangement of and control for refrigerant evaporating means which is arranged and operated without the collection of frost thereon or a slight film of frost is allowed'to collect thereon during the on-phase of the refrigerating cycle and is melted off during the oil-phase of the refrigerating cycle, while at the same time provisions are made for freezing substances, such as ice cubes and the like and for cooling circulating air in the food storage compartment whereby continuous refrigeration at substantially constant, predetermined temperatures is assured and the necessity of periodic inoperative conditions of the system for defrosting is avoided.

Another object of my-invention is to provide an improved arrangement for the ready removability of the aforesaid refrigerant evaporators and the condensing element as a unitary structure without uncoupling the devices from one another.

Other objects and advantages will be apparent from the following description, reference being had to the accompanying drawings.

In the drawings:

Fig. 1 is a side vertical view in cross section of a refrigerating apparatus embodying features of my invention;

Fig. 2 is a view taken along the Fig. 1; r

Fig. 3 is a horizontal view in cross section of the apparatus embodying features of my invention;

- Figs. 4 to 6 are graphs indicating the cyclic operations of the system under various conditions;

Fig. '1 is a vertical view in cross section of a control valve embodying features of my invention;

Fig. 8 is a diagrammatic representation of the switch mechanism used for controlling the operation of the system;

Fig. 9 is a side vertical view in cross section of a modified form of refrigerating apparatus embodying features of my invention;

Fig. 10 is a front view partly in elevation and line 2-2 of Fig. 9; and

Fig. 11 is a view taken along the line "-1 l of Fig. '7.

Referring to the drawings, thehumeral 20 designates, in general, a cabinet having a compartment 22 for'the storage of foods to be refrigerated,

a freezing compartment 23 and a machine compartment 24. The cabinet is constructed of insulated walls, including side walls 26, rear wall 21, front wall 28, bottom wall 29 and top wall 30. The cabinet also includes a fixed, substantially, horizontally disposed, insulated wall 32. The wall 32 extends across the width of the cabinet and from the rear wall to a point adjacent the front wall, separating the food compartment from the freezing compartment and machine compartment. An inner metallic lining member 35 forms the inner walls of the food compartment and'is, preferably, provided with a coating of vitreous enamel, such as porcelain, to provide a neat appearing compartment and one which may be easily cleaned. The front wall 28 is provided with an opening 31 through which access may be had to the food compartment and freezing compartment.

The opening 31 is closed by door 38.

A unitary structure is arranged to be inserted in and removable from the cabinet through the As shown in the drawings, the refrigerant evaporating element 46 is of the flat plate type and is horizontally disposed substantially midway between the top wall 86 and the wall 82 in the compartment 23. The evaporator 46 may be secured to the upright partition 44 by any suitable means. Preferably, the element is constructed of sheet metal plates whichare secured together about the peripheries thereof by seam welding and welded at various points intermediate their edges, but spaced apart between the welded points to provide a space for refrigerant. By locating the evaporating element 48 substantially midway between the walls 80 and 32, and by operating said element at temperatures sufliciently low enough to freeze substances, said substances may be frozen rapidly by placing same on the upper part of the evaporating element and if desired, when frozen, may be removed to be stored and retained in a frozen condition 'by placing same on .the upper part of the wall 32 in compartment 28 immediately below the evaporating element 40. In the drawings, I have shown conventional ice trays 48 mounted on top of the element 40 to freeze substances therein. When the substances are frozen, the trays may be transferred to the space immediately below the evaporating element and additional trays may be mounted on the plate evaporating element to freeze additional substances therein. Thus, it will be noted that I have provided for rapidly freezing large quantities of ice cubes or other substances, and in addition I have provided a large space for storing said substances in a frozen condition.

In order to prevent the circulating air in the food storage compartment 22 from entering the freezing compartment 123,'I have provided a closure plate 50 for the front of compartment 23. Plate 50 is provided with openings 52 closed by doors 53. Doors 58 and openings 62 provide ready access to the interior of compartment 23.

Evaporating element 46 may be of similar construction as evaporating element 48 and is vertically disposed in the food storage compartment adjacent the rear wall 27 but slightly spaced therefrom to permit circulating air in the compartment 22 to ass on all sides of the element 46. A plurality of U-shaped heat absorbing fins are secured to the one side of evaporating element 46 to increase the heat transfer characteristics thereof.

The refrigerant condensing element 42 comprises, ingeneral, a motor compressor unit 60, condenser 62, motor driven fan 63 and highside float mechanism 66. The motor compressor unit is of the type which includes a compressor and motor directly connected which are enclosed within a hermetically sealed casing. Units of this type are well known in the art and further illustration thereof in the drawings is deemed unnecessary. Thecompressor withdraws evaporated refrigerant from the evaporating elements through a vapor conduit 61, compresses the gaseous refrigerant and delivers it to the condenser 62 wherein it is liquefied and from which it is delivered to the high side float mechanism a. liquid refrigerant is delivered to the evaporating elements through conduit 86 under the control of v the high side float mechanism 66. The electricaily operated fan 68 is employed for circulating orating element 46 through the'conduit 66, and.

from the evaporating element 46 liquid and gaseous refrigerant is delivered to the evaporating "element 4ll-through a conduit ll. Evaporated refrigerant is withdrawn from the evaporating element 40 through the vapor conduit 61.

As will be noted in Fig. 2 of the drawings, the wall '82 is provided with slots 12 for receiving conduits I0 and 68. The slots 12 extend from a point in the wall 82 adjacent thepartition 44 to the front of wall 82 to permit the ready removal of the evaporating elements 46 and 46 and condensing element 42 without uncoupling said devices from one another, as is hereinafter more fully described. The slots 12 are normally closed by slabs of insulating material 15.

-Preferably, the condensing element isintermittently operated. In order to control the op- ,eration of the condensing element, I have provided a thermostatically controlled switch 86 to which is connected a thermostat fluid containing bulb 82 which is disposed in thermal contact with the evaporating element 46 so that the switch operates in response to changes in temperature within the evaporating element 46. The switch 80 is adapted to open and close the circuit to the motor of unit in response to predetermined changes in temperature within the evaporating element 46. In view of the fact that the evaporating elements 48 and 46 are of the so-called flooded type, the temperature therein will bear a direct relation to the pressures existing therein.

Referring in detail to Fig. 8, the thermostatic switch comprises, in general, a casing which houses the operating parts of the switch. The switch mechanism includes an expansible bellows 81, which is connected to the thermostatic bulb 82 by means of a conduit 68. The bellows 88 is disposed in engagement with a pivotally mounted lever 90 which moves upwardly and downwardly, depending upon the movement of the bellows 81. The lever 90 is adapted to actuate suitable leverage mechanism 92 for controlling the opening and closing of contacts 94. Contacts 94 control an electric circuit 86 which leads to the motor to thereby control the flow of current from power spring I00 to thereby vary the cut in and cut out periods of the motor of unit 60. Thus, the 'thermostatic switch 86 controls the operating periods of the condensing element to thereby control the temperatures within the evaporating elements 46 and 46. It will also be noted that the switch is controlled in response to changes in temperatures within the evaporating element 46.

In order to maintain a predetermined temperature differential between the evaporating element 40 and the evaporating element 46, I have provided a pressure responsive valve which is interposed in the conduit III for controlling the flow ed to maintain a predetermined pressure dif-.

ferential between the evaporating element 49 and the evaporating element 46 to thus maintain a temperature differential between said evaporating elements. As shown in Fig. 7, the pressure responsive valve includes a valve proper I91 and a valve seat I98 located within a casing I99. The casing I99 is provided with an inlet H9 to which the outlet end of conduit I9 is connected. and an outlet H2. The evaporating element 491s connected to outlet H2. The valve proper I9'I is secured to a weight H6 which is adapted to move upwardly and downwardly within a chamber H6, depending upon the pressure of the refrigerant exerted on the valve properl9'l. Preferably, the

chamber I I6 is cylindrical in shape and also, preferably, the weight I I is provided with a plurality of arcu'ate portions H9 which conform to the contour of the walls of the chamber. The weight is. also provided with cutaway flat portions H9 between the arcuate portions I I9 -to provide spaces between the walls of the chamber and the weight so as to prevent binding of the. weight in the chamber, and also to prevent a dash pot action therein. When the pressure of the refrigerant in the evaporating element 46 reaches a predetermined point for example, equal to the pressure within the evaporatingelement 49 and is of sufficient force to lift weight H5 and the valve proper), the liquid and gaseous refrigerant will move the valve proper I91 and weight H5 upwardly to allow liquid and gaseous refrigerant to enter the chamber H6, whence it passes through outlet H2 into evaporating element 49.. When the pressure recedes to a predetermined point for example, to a point less than that required to open valve I91, the weight and valve proper move downwardly to cause the valve I91 to engage itself with seat I96 to prevent further passage of' refrigerant into the evaporating element 49. The weighted valve is arranged to be interm ttently operated so as to maintain a predetermined pressure diiferential between the evaporating elements 49 and. As previously stated herein, the pressure differential is controlled by the weight of the weighted valve proper I91. In other words, before refrigerant may pass from the evaporator 46 to the evaporating element 49, the pressure within the evaporating element 46 must be equal to the pressure in the evaporating element 49, plus an amount equal to move the weight H5 upwardly to remove the valve I91 from its seat I98. This predetermined pressure differential is maintained irrespective of the temperatures maintained in the evaporating elements and 46.

Preferably, the thermostat is set'so that the evaporating element 49 will be operated at temperatures which cause rapid freezing, and the evaporating element 46 at temperatures which are slightly above that which would be likely to cause the collection of frost or ice thereon due to the deposit of moisture from the circulating. air in the food compartment. If desired, the thermostat may be set to operate evaporating element 46 at a temperature which would allow a slight film of ice to collect thereon during the onphase of the refrigerating cycle and melted off during the off-phase of the refrigerating cycle. In view of the fact that the refrigerant condensing element 42 is operated in response to changes in temperature within the evaporating element 46, the adjustable spring I99 of thermo- '46. cycling takes place between an upper limit A stat 99 maybe set so as to provide for operating the evaporating element 46 at either of the. desired temperatures.

In the refrigerating system herein described.

I prefer to use sulphur dioxide as the refrigerant. When sulphur dioxide is used as the re- -frigerant and when a predetermined setting of switch, is made, Ihave found that the cyclic 4 of said unit, and F representsthe pressure in cycling is between said element when the motor is cut out of circuit to render the compressor inoperative to perform its compressingfunction. When sulphur dioxide is used as the refrigerant, the upper pressure range limit Emay be 14' pounds pressure and the lower pressure range limit may be four pounds pressure of the refrigerant inclement In Fig. 4, it will be noted that the normal and a lower limit B in element 49. The upper limit A and the lower limit B may be four pounds pressure and six inches of vacuum, respectively. Thus, it will be noted that a predetermined pressure differential of seven pounds is maintained between elements 49 and 46-while the unit is operating during normal cycling operation and this is accomplished by the weighted valve I95, and the operation of the unit 69 is controlled by thermostatic switch'll li in response to changes in temperature in evaporating element 46.

Assuming now a large quantity of substances to be frozen is applied to the ice freezing plate or evaporating element 49, the pressure of the refrigerant in element 49 is increased by the heat of the substances and the element 49 operates ona curve different from the normal cycling curve between the A and B limits. As shown in Fig. 4, the upper limit is at C, which is, for example, nine pounds pressure of the refrigerant, and the lower limit is at D, which is six inches of vacuum. When this occurs, the pressure of the refrigerant also increases in evaporating element 46 after that liquid is then supplied to element 46 at a pressure higher than that already in said element, and as aresult of the pressure in element 49 'being increased above normal cycling limits, the pressures in element 46 are increased until the pressure differential maintained by the valve I95 is attained. As will be noted, the pressure dif-'- ferential maintained by thevalve,l9,5 during operation of the condensing element is seven pounds since the lower pressure limit B of element 49 is 6 inches of vacuum, and the lower pressure limit E of element 46 is four pounds pressure of the refrigerant when the unit 69 ceases operation. As indicated, the pressure range in element 46 is varied with the upper limit being at G, which is, for example, 16 pounds pressure, and the lower limit A, whichis four pounds pressure of the refrigerant. Thus, it will be noted, that as the temperature in element 46 rises to a temperature corresponding to 14 pounds pressure, the thermostatic switch 65 cuts in the motor-compressor unit 69 to reduce the pressures in the elements 49 and 46, which gradually takes place as the heat of the substances to be frozen is gradually dissipated by being absorbed in the refrigerant and withdrawn from elements the unit 69 begins operation owing to the fact 40 and 44 by the motor-compressor unit. As will be noted in Figs. 4 and'5, the placing of a large quantity of substances to be frozen in the element 40 causes the elements 40 and 46 to operate on curves CD and (3-H, respectively which are at pressure range limits different from normal cycling, and it is also to be noted that the average mean temperatures. existing in the evaporating elements are substantially the same as the temperatures existing therein during normal cycling. Thus, it will be noted that the placing of a large quantity of substances to be frozen on element 40 will, after operation of the motorcompressor unit has started, cause it to continue to operate until the substances are either entirely or substantially frozen even though the operation of the motor-compressor unit is controlled in response to changes In temperatures in the evaporating element 46. This is due to the pressure differential maintained by valve I05 which prevents the pressure in element 46 to be lowered to four pounds until the pressure in element 40 is lowered to six inches of vacuum, at which time the substances are frozen. In the event an abnormal large quantity of warm foods should be placed in the food compartment, the pressures in each evaporating element is similarly increased until lowered by the action of the condensing element 42.

Although I have disclosed my pressure differential valve I05 in connection with an intermittently operated refrigerating system, it will be readily apparent from the foregoing that in a continuously operated system, the valve I05 would maintain a predetermined pressure differential between the elements 40 and 46 at all times.

In' Fig. 6 there is shown a graph indicating normal cycling operation between predetermined upper and lower pressure range limits in which I is the upper limit and .I the lower limit. The pres- .may be varied by adjustment of screw IOI- to vary the effectiveness of spring I00. As shown, the upper and lower limits have been increased with the upper limit being at K and the lower limit at L. By varying the upper and lower pressure range limits in the evaporating element 46, the upper and lower pressure range limits are correspondingly varied in the evaporating element 40 owing to the pressure responsive valve I05, which maintains a predetermined pressure differential between the two evaporating elements 5 40 and 46.

From 'the foregoing, it will be noted that I have provided an improved and simple arrangement for maintaining a pressure differential between a number of different evaporating elements for maintaining a temperature diiferential therebetween. It will also be noted that the pressure differential is obtained automatically throughout variations in pressure range limits existing in the different evaporating elements. In addition, it is to be noted that the pressure range limits may be set at any desired operating limits by simply adjusting a single manually operable screw without in any way effecting the temperature differential maintained between the different evaporating elements by the provision of the pressure responsive valve I05. Furthermore; it will be noted that in maintaining a predetermined pressure differential, rapid ice freezing is promoted, since the condensing element when once started continues to operate until the ice is frozern As previously stated herein, the entire refrigerating system may be removed from the cabinet as a unitary structure. The structure includes the condensing element 42, upright separating wall 44, metallic member I22, which includes an upright portion which is secured to wall 44 and a horizontal portion which-rests on wall 32, evaporating element 46, evaporating element 40, a sheet metal member I24, which includes an upright portion which is secured to the wall 44 and a horizontal portion which rests on wall 32, front closure plate 50 and doors 53. Preferably, the evaporating element is secured to rear wall 21 by screws (not shown) so that it may be readily removed from the wall 21. The entire structure as a unit may be moved forward with portions above wall 32 sliding thereon andthe conduits 66' and moving in slots or notches12. The entire structure, after clearing wall .32, may be removed from the cabinet through opening 31.

Referring now to Figs. 9 and 10, there is shown a cabinet I30, which is similar to cabinet 20, and

includes a food storage compartment I32, ma-

chine compartment I34 and a freezing compartment I35. The cabinet is formed of insulated walls,-including top wall I31, bottom wall I36, rear wall I39, front wall I40, a substantially horizontal, fixed wall I43 located between the top wall I31 and bottom wall I33 to separate the food compartment I32 from compartments I34 and I 35, and upright wall I45 between compartments I34'and I35. The front wall I40 is provided with an opening I50 through which access may be had to compartments I32 and I35.

' The opening I50 is closed by door I5I. The upright wall I45 is provided with an opening I52 which is closed by a movable closure wall I54.

The closure wall is adapted to support a primary refrigerant evaporator I56 within compartment I and an intermittently operated refrigerant condensing element I58, which may be similar to element 42, within compartment I34. The condensing element is operatively connected to the evaporating element I56 by conduits I60 and "II. The front of c'ompartment I 35 is arranged to be closed by a closure plate I65, which is provided with an opening I66 through which access to the. interior of compartment I35 may be had. If desired, the opening I66 may be closed by doors (not shown) similar to doors 53 shown in Figs. 1 and'2. Preferably, the apparatus including condensing element I58, evaporating element I56, wall I54 and front closure plate I65 are removed from the cabinet as a unitary structure by simply moving same forward through opening I50. The operating of element I56 may be controlled by any suitable control means (not shown).

In order to cool the food compartment I32, I have provided a secondary refrigerant evaporating element I10. The element may be similar to element 46 and is located in the cabinet in a like manner as iselement 46. However, liquid refrigerant and evaporated refrigerant enter and leave the element I10 through a single conduit I12. The conduit I12 is connected to a condenser I14 disposed immediately below the evaporating element I56 and in thermal contact therewith to effect condensation in the condenser I14.

Evaporated refrigerant passes from evaporating element I10 through conduit I12 to condenser I14 wherein it is condensed by the refrigerating action of element I56, and the liquefied refrigerant is returned to the evaporating element l'lll through conduit H2. If desired, a baffle I15 is placed in front of the element I10 to direct the air flow about the element I10.

In the apparatus shown in Figs. 9 and 10, the primary system, including the condensing element and evaporating element 156, may be removed for repairs and the like while the secondary system is, preferably, permanently installed in the cabinet, for the reason that the secondary system has no operating mechanism to necessitate repairs.

Preferably, the contact between the condenser I14 and the evaporating element I56 is such that during periods when the condensing element I58 is inoperative or, in other words, during the offphase of the refrigerating cycle, the condensing surface is inadequate to condense all of the evaporated refrigerant in the secondary system which permits the element I10 to warm up to thereby melt the frost formed on its exterior surface. Thus, the evaporating element I56 may be operated at temperatures sufficiently low enough for freezing purposes and the evaporating element I10 is arranged to automatically defrost itself between off and on-phases of the refrigerating cycle. Inasmuch as the evaporating element is closed to the circulating air in the compartment I32, it will be unnecessary to frequently, if at all, defrost this element.

Although only a preferred form ofthe invention has been illustrated, and that form described in detail, it will be apparent to those skilled in the art that variousmodifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. Refrigerating apparatus comprising, in combination, a cabinet provided with an opening and having its interior divided into a food compartment and a second compartment by a hori- 'above said horizontal wall, a refrigerant condensing element disposed on one side of said vertical wall, a refrigerant evaporator disposed in said second compartment on the opposite side of said vertical wall, a vertically disposed plate type evaporator located in said food compartment adjacent the rear wall thereof, and a conduit extending through said notch and interconnecting said evaporators, said evaporators, removable wall and condensing element being removable bodily as a unit from said cabinet through said opening.

2. Refrigerating apparatus comprising, in combination, a cabinet having its interior divided into a food compartment and a second compartment by a horizontal, fixed insulating wall, said cabinet also including a vertical insulated wall above said fixed wall, a refrigerant condensing element disposed on one side of said vertical wall, a refrigerant evaporator disposed in said second compartment on the opposite side of said vertical wall, and a verticallydisposed plate type evaporator disposed in said food compartment adjacent the rear wall thereof.

3. Refrigerating-apparatus comprising, in combination, a cabinet having its interior divided into two compartments, a primary refrigerating system including a refrigerant condensing ele-' ment and a refrigerant evaporator located in one of said compartments, and a secondaryrefrigerating system including a refrigerant evaporator located in the other compartment, and a condenser located in the compartment with the primary evaporator and in thermal contact therewith, said secondary system being permanently fixed in said cabinet, and said primary system being bodily removable as a'unit from the cabinet without disturbing the secondary system.

4. Refrigerating apparatus comprising, in combination, a cabinet having substantially horizontal top and bottom insulated walls, said cabinet also including a wall located intermediate the top and bottom walls to divide the interior of said cabinet into a food compartment and a second compartment and a flat plate refrigerant evaporator disposed substantially midway between said top and intermediate insulated walls to provide a rapid freezing support for a recep-v tacle on its upper surface and a storage space fora like receptacle therebelow.

5. Refrigerating apparatus comprising, in combination, an insulated cabinet, means dividing said cabinet into two compartments, said cabinet havingan opening through a wall thereof opening into one of said compartments, an insulated member removably mounted in said opening, a primary refrigerant evaporator secured to said member and extending into said one compartment, a secondary refrigerant evaporator associated with said other compartment, a condenser for said secondary refrigerant evaporator, said condenser being fixedin the said one compartment and in heat exchange relation with said primary refrigerant evaporator, and condensing means exteriorly of the said one compartment for said primary, refrigerant evaporator.

6. Refrigerating apparatus comprising a cabinet having insulated walls, a substantially imperforate partition element dividing the cabinet into two. compartments, a primary refrigerating system including an evaporator rem'ovably located in one of said compartments, a second evaporator in heat exchange with the other of said compartments, a condenser connected to said second named evaporator, said condenser being associated with said primary system in such manneras to permit the removal of the primary system and to condense refrigerant evaporated in the; secondary evaporator, said primary system also including a liquefying element operatively connected to the evaporator thereof, and said cabinet having an opening in a wall thereof to facilitate the removal of said primary system from the cabinet and movable insulating means associated with said opening.

7. Refrigerating apparatus comprisingjn combination, an insulated cabinet having means dividing the interior of the same into two compartwith said evaporator through said insulating means, and a secondary refrigerating system including an evaporator associated with said other compartment and condensing means connected with said last named evaporator and associated in heat exchange relationship with said primary refrigerating system.

LAWRENCE A. PHILIPP.

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