US2207125A - Refrigerant system and apparatus - Google Patents

Description

July 9, 1940.

C..A. KUEBLER ET AL.

REFRIGERANT SYSTEM AND APlARATUS Filed Feb. ll, 1937 2 Sheets-Sheet l CHESTER A. KUEBLER. mo WILLIAM J. BQLTONNVENTORS- BY QL@ 'rm-R ATTORNEYS 2 *Sheets-Sheet 2 I@Il F I G. 5.

c. A. KUEBLER Er A1.

REFRIGERANT SYSTEM AND APPARATUS Filed Feb. 1l, 1937 INVENTORS WILLIAM J. BOLTON.

'Ck-il THUQATT RNEYS- Dnl E L nD E U K A D E Tl s E H C AND FIG. 6.

July 9, 1940.

?Patented July '9, 1940 REFRIGERANT SYSTEM AND APPARATUS Chester A. Kuehler and William J. Bolton, Erie,

Pa., assignors to Uniiiow Manufacturing 00mpany, Erie, Pa., a corporation of Pennsylvania A Application February 11, 1937, Serial No. 125,239

4 Claims.

This invention relates to a mechanical refrigerator and more particularly to an improved refrigerant system for providing cooling zones of different temperatures.

It is highly desirable in various types of mechanical refrigerating apparatus that cooling zones of different temperatures be provided. For example, the conventional domestic electric refrigerator comprises a main heat insulated cabinet with a cooling unit therein which is adapted to maintain a freezing temperature within an ice tray compartment and a somewhat higher temperature such as 40 inthe cabinet generally. However, when it is desired to effect rapid freezing of ice cubes, the refrigerant pressure in the evaporator is substantially lowered resulting in a sub-freezing temperature in the coils disposed adjacent the external walls of the ice tray compartment and the temperature throughout the main cabinet is often lowered to near the freezing point. This results in the absorption of moisture from articles stored in the cabinet to an undesirable degree, particularly meats and similar articles, and also from the air in the cabinet considerably lowering the humidity with a resultant deposit of frost on the evaporator coils. Under these conditions the humidity will be approximately 25% whereas for the proper preservation of foods it should be at a considerably higher value, such Additionally, the coating of frost on the evaporator coils due to the freezing and subfreezing temperatures acts as an insulating medium resulting in inelcient heat exchange and.

necessitating frequent defrosting.

We have devised a refrigerant system adapted to domestic refrigerators wherein the ice tray compartment although disposed in the main cabinet is insulated therefrom, effecting quick formation of ice, the coils associated with the external walls of the ice tray compartment are not sub- Jected to freezing temperatures whereby the temperature of the food storage cabinet generally is not lowered to the freezing point but is maintained at a desired normal operating temperature such as 40 F. Thus, the cooling action during quick freezing of ice tubes is confined substantiallyentirely to effecting freezing and subfreezing temperatures within the ice tray compartment only, resulting in low current consumption by the compressor and relatively little moisture is extracted from articles in the main cabinet and from the air within the cabinet. A relatively high humidity such as 65% is thereby maintained in the storage cabinet and since the coils externally of the ice tray. compartment are maintained above freezing temperatures at all times, there is no frost deposit on these coils.

- We are familiar with various systems endeavoring to achieve this result by providing two independent systems one controlled by the cabinet temperature and the other by the temperature of the ice cube compartment and also systems of the double transfer type. However, we employ a single, relatively simple, inexpensive system for both the cabinet and the ice tray compartment and quick freezing is effected Within the ice tray compartment by manipulation of a manual control valve wherein a relatively lower refrigerant pressure is obtained in the portion of the refrigerator conduit system cooling the ice tray compartment than in the portion of said system cooling vthe cabinet generally.

The primary object of our invention therefore is to provide a single refrigerant system wherein a refrigerant pressure may be maintained in one portion of the system effecting freezing and subfreezing temperatures and a relatively higher refrigerant pressure may vbe obtained in another portion of the system effecting non-freezing temperatures.

Another object of our invention is to provide a single refrigerant system for refrigerators having relatively heat insulated compartments adapted to be maintained at the same or different temperatures optionally, wherein the temperature of one compartment may be substantially maintained at constant above freezing temperature, and another compartment may be subjected to near-freezing or sub-freezing temperatures upon operation of a manual valve.

Another object of our invention is to provide a refrigerant system for domestic refrigerators comprising a main cabinet and a relatively heat insulated ice tray compartment disposed therein and wherein the-temperature of the evaporator coils in the main cabinet may be maintained above freezing to prevent frost formation on the coils and the temperature of the ice tray compartment may be manually controlled to alter the rate of freezing without altering the temperature of the main cabinet.

Another object of our invention is to provide a, refrigerator of the above type which is relatively eiiicient requiring an extremely low current consumption due to short operating time obtained when both coils are operated at high pressure and temperature, making the compressor operation very emcient due to the resulting high back pressure and providing a relatively high degree of humidity in the main cabinet at all times, even when the freezing compartment coil is operated at sub-freezing temperature.

Another object of our invention is to provide a domestic refrigerator of the above type which is relatively eicient requiring a low current consumption and which maintains a relatively high degree of humidity in the main cabinet.

Other objects of our invention and the invention itself will become increasingly apparent from a consideration of the following description and drawings herein:

Fig. 1 is a front elevational view of a domestic refrigerator embodying our invention;

Fig. 2 is a diagrammatic view of the refrigerant system illustrated in Fig. 1;

Fig. 3 is a perspective view of a cooling unit, including an ice tray compartment which we may employ in the refrigerator illustrated 1n Fig. 1 and with a closure portion removed;

Fig. 4 is a perspective View of a closure portion for the unit of Fig 3;

Fig. 5 is a longitudinal sectional view of a manual control valve which we may employ in the system of Fig. 2, and

Fig. 6 is a section taken along line 6 6 of Fig. 3.

Referring now to the drawings, we have illustrated generally at I0, Fig. 1, a domestic refrigerator of the type generally illustrated in a patent to C. A. Kuebler, No. 2,064,926 but embodying our improved system. Although for purpose of illustration, we have shown our system as embodied in a domestic type refrigerator, it is understood that it is equally adaptable to commercial apparatus of varying types having two relatively insulated compartments maintained at different temperatures wherein it is desired to rapidly reduce the temperature of one compartment without substantially effecting the temperature in other compartments. The refrigerator I Il comprises the usual compartment Il in the bottom portion of the refrigerator for housing the compressor-condenser unit, a main storage compartment I2 within which is disposed a cooling unit I3, preferably secured to the top of cabinet I2. Beneath the main storage compartment I2 we may provide an auxiliary compartment I4 adapted to -be cooled from the main compartment but the particular construction of the refrigerator apart from the refrigerant system, constitutes no essential part of our invention and may take any form desired. The refrigerant system illustrated in Figs. 1 and 2 comprises the usual compressor unit I5 operable by an electric motor I6 whereby refrigerant gas under pressure will pass from the compressor I5 to the usual condenser unit I1 and will then pass in liquid form through a conducting line I8 to a iioat FVvalve I9. The float valve I9 admits liquid refrigerant to a coil 20 having heat conducting fins generally indicated at 2| associated therewith. 'I'he refrigerant will then pass by a line 22 to a manually controllable valve 23 and thence to a coil 24 having an outlet in a header 25 from which the refrigerant is conducted back. to the compressor or pump I5 by line 26.

'Ihe valve 23 also has a connection with a tube 21 leading to a switch 28 controlling the operation of the compressor motor I6. Although switch 28 is illustrated as being operably responsive to pressure in tube 21, it is understood that a thermally responsive switch may be employed, both types of switches being of well known construction. Also, a conventional pressure responsive expansion valve may be used in place of the float valve I9, but for operating results We4 prefer the float type valve.

Referring now to Figs. 3, 4 and 6 illustrating the cooling unit I3, it will be noted that the cooling unit comprises a generally boxed shaped sheet metal housing 30 having out-turned lateral flanges 3I-3I whereby the housing may be welded or otherwise suitably secured to the top of the main storage compartment I2. "he housing 30 is internally lined at the base, side and rear walls with suitable heat insulating material indicated at 32, the insulating material 32 extending upwardly for a major portion of the housing height. A plurality of sheet metal shelves 33 are supported in spaced relation within the housing 30. 'I'he external walls of the housing 30 are provided with a plurality of vertically extending heat conducting fins generally indicated at 2| preferably by securing a corrugated sheet metal strip to the lateral and rear walls of the housing, although the heat exchange area of fins 2| will be dependent upon the heat exchange surface required to properly cool the main compartment I2. The coils 20 are disposed intermediate the fins 2I and refrigerant will ow from oat valve I9 through a line 34 to the coils 20 and thence through line 22 projected through a lateral wall of housing 30 to the control valve 23. The refrigerant passes from control valve 23 to coils 24, which are disposed beneath shelves 33 by a line 35. We contemplate it will only be necessary to dispose coils 24 beneath some of the shelves 33 to effect the desired temperature within the ice tray compartment, but this arrangement may be altered as desired and we preferably place a pan immediately beneath the coils as indicated at 36 to prevent frost and the like from being deposited on trays supported on a lower shelf.

The door frame indicated at 31 is preferably molded of suitable heat insulated material and is secured to the front face of housing 30 in any suitable manner, the frame. being provided with a hinged door 38 also heat insulated permitting access to the interior of housing 30. The top portion of frame 31 is perforated as indicated at 39 whereby a control member for switch 28 may be projected therethrough and is also perforated at 40 whereby a control member for valve 23 may be projected therethrough, thus rendering these control members easily accessible for manual manipulation upon opening the door of main cabinet I2.

The construction of control valve 23, best illustrated in Fig. 5, will now be described. The valve 23 comprises a generally cylindrical element 4I provided with an enlarged threaded bore 42 extending into a relatively reduced forward portion 43 and terminating in a further reduced co-axially disposed forward portion 44, the forward portion 44 having a generally frusto-conical valve seat 45. Extending from portion 44 is a lateral inlet 46 to which line 22 is sealingly secured and a lateral outlet 41 to which line 35 is sealingly connected. The portion 43 and the lateral inlet 46 are connected by a relatively small by-pass 48 and disposed within portion 43 is a generally cylindrical valve element 49 having a conical tip adapted to engage valve seat 45 and an enlarged shoulder portion 50 slideably engaging the walls of portion 43. A compression spring 5I abuts a shoulder formed abuts the shoulder portion Knr intermediatedioredrportionseand l 55 of van 49 and tends to maintain the valve element spaced from its valve seat. The enlarged shoulder portion 50 of the valve element is recessed to receive the inner end of an axially movable pin 52, the pin 52 being movable' by a toggle cam 53. nut-{Lthreadedlygengageborewqf of ent 4| and is centrally bored to permit the ember 52 to be projected therethrough. The enlarged shoulder portion 50 of valve element 49 is sealingly connected to one end of a Sylphon bellows 55 and the oppositebellows end is sealingly connected to the outer portion of bore 43 preventing leakage of refrigerant uid. The nut 54 is adapted to engage a second nut 55 to grip therebetween peripheral portions of the frame perforation 40 as indicated at 51 to form a secure mounting for the control valve 2l.

'I'he portion 44 of the element 4I is also provided with a relatively small lateral opening 55 to which the tube'21 leading to switch 28 is connected whereby the pressure of refrigerant in coil 20 and the portion 44 will be communicated to the pressure responsive element 'controlling switch operation. y k

'Ihe operation of the system will now be described; As previously stated, refrigerant nows from the coils 20 disposed externally of housing 30 to the coils 24 disposed internally of thehousing and now into coil 24 is controlled by valve 23. With the handle of the toggle cam 53 in the position illustrated in Fig. 5 the flow of refrigerant from coil 20 to the inlet passage 45 and through outlet passage 41 will be substantially unrestricted and the refrigerant pressure and consequently temperature in both coils 20 and 24 will be-substantlally the same. Under these conditions, the ice tray compartment would be only slightly cooler than the food compartment generally and since the compressor is caused to operate with refrigerant at relatively high back pressure, it is relatively economical. If the handle of the toggle cam 53 were turned to closed position or downwardly, the movement of pin 52 would cause valve element 49 to close the passage leading to outlet 41. Any refrigerant passing to the outlet 41 would necessarily traverse the small by-pass 48 and this would cause a restriction and result in lowering the pressure at outlet 41 and cause the refrigerant uid in coil 24 to be evaporated at a lower temperature. Refrigerant fluid in coil 20 would be evaporated more slowly since switch 28 is responsive to the pressure of refrigerant fluid in coil 20 through the connecting tube 21 but the pressure of refrigerant fluid in coil 20 would remain substantially the same since the operation of the compressor pump in starting and stopping would control this pressure.

The pressure at which switch 28 cuts the compressor out of operation corresponds to a temperature slightly above freezing such as 35 Fahrenheit so that there is no tendency for frost to accumulate on coils 20 either during normal operation of the refrigerator or when adjusted to eiect quick ice formation in the ice tray compartment.

Thus, we have provided a relatively simple and inexpensive system of refrigeration wherein two cooling zones of di'erent temperatures may be maintained and the temperature of each zone may be manually controlled. The temperature of the food compartment generally may be controlled through manipulation of switch 28 operating the compressor and the temperature of the ice tray compartment through the adjustable valve 23.

' During periods when the valve 23 is maintained open both coils 20 and 24 will have substantially the same temperature and the compressor will be operating under a relatively high back pressure of refrigerant uid resulting in economical operation.

,Although we have shown and described modiilcations of our invention, we contemplate that numerous and extensive departures may be made therefrom without departing from the spirit of our invention or the scope of the appended claims. Having thus `described our invention, what we claim is:

l. A cooling unit for a refrigerator comprising a generally box-shaped housing adapted to be v mounted in the food storage compartment of the refrigerator and having heat insulated walls, evaporator coils secured to the external walls of the housing, heat conducting flns associated with the coils extending outwardly from the housing walls, a plurality of shelves within the housing, evaporator coils disposed within the housing and adjacent the shelves, conduit means projected through the housing walls connecting the externally and internally disposed coils, a manually controllable pressure reducing valve disposed in the conduit means for adjustably reducing the pressure of refrigerant fluid in the internally disposed coils relative to the externally disposed coils, and means associated with said valve adapted to transmit refrigerant pressure in the external coils to a pressure responsive electric switch'.

2. A cooling unit for a refrigerator comprising a generally box-shaped housing adapted to be mounted in the food storage compartment of the refrigerator and having heat insulated walls, an evaporator coil, secured to the external walls of the housing. a shelf within the housing, evaporator coils disposed within the housing and adjacent the shelf, conduit means connecting the externally and internally disposed coils, a manually controllable pressure reducing valve disposed in the conduit means for adlustably reducing the pressure of refrigerant uid in the internally disposed coils relative to the externally disposed coils, and means associated with said valve adapted to transmit refrigerant pressure in the external coil to a pressure responsive electric switch.

3. A cooling unit for a refrigerator comprising a generally box-shaped housing adapted to be mounted in the storage compartment of the refrigerator and having heat insulated walls, evaporator coils associated with the external walls of the housing, a shelf within the housing, evaporator coils disposed within the housing and adiacent the shelves, conduit means connecting the externally and internally disposed coils, a manually controllable pressure reducing valve disposed in the conduit means for adjustably reducing,

pressure of refrigerant fluid in the internally disposed coils relative to the externally disposed coils, and said pressure reducing valve being accessible externally of the housing.A

4. A cooling unit for a refrigerator comprising -a generally box-shaped housing adapted to be externally and internally disposed coils, a. manupressure responsive electric switch connected with ally controllable pressure reducing valve disposed the valve, and a compartment in the upper porin the conduit means for, adjustably reducing tion of the housing within which the switch, tho the pressure of refrigerant fluid in the internally valve and the tank are disposed.

disposed coils relative to the externally disposed CHESTER A. KUEBLER. coils, a receiving tank for refrigerant iiuids, a WILLIAMJ. BOLTON.

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