US2262025A - Refrigeration apparatus - Google Patents

Description

Nov. 11, 1941. p MARCY REFRIGERATION APPARATUS Filed March 8, 1939 INVENTOR GERALD 1-? 11m Patented Nov. 11, 1941 I 2,262,025 REFRIGERATION APPARATUS Gerald P. Marcy, Springfield, Mass, assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 8, 1939, Serial No. 260,500

2 Claims. (01. 200-138) My invention relates to control apparatus and it has for an object to provide improved apparatus of this kind.

A further object of my invention is to provide electrical and heat insulating base member [4, preferably formed of a material such as hard rubber or a molded plastic composition.

The base member I4 is provided with an openimproved control apparatus for refrigerating ma- 5 ing IS in which a tapped metal bushing I6 is chines which is inexpensive to construct and disposed. A threaded shaft I1 is screwed into which may be readily applied to various forms the metal bushing l6 and extends outwardly of refrigerators. therefrom a considerable distance. A stop 20 in It is a further object of the invention to provide the form of a bolt head is provided at the end an improved control apparatus employingasnap- 10 of the shaft I! for a purpose hereinafter deacting thermal device that may be adjusted to scribed. The supporting fingers l8, a detail of maintain different temperatures. which is shown in Fig. 3, are molded into the A still further object of the invention is to base member I4. As shown in Fig. 2, three provide an improved control mechanism includequally spaced supporting fingers l8 are provided ing a hermetically sealed switch structure and to adjacent the periphery of the base member l4. provide for adjustment of the switch structure A bi-metal snap-acting disk I9 is supported by so that the temperatures at which the contacts the fingers l8 and is provided with an aperture are opened and closed may be varied at will. 2|) in the center thereof through which the It is another object of my invention to imthreaded shaft l'l extends. prove the heat transfer qualities of a hermetically An insulating bushing 22 is slidably mounted sealed control mechanism of th bi-metal theron the shaft IT and a shoulder 23 thereof is held mostat type; and furthermore, by increasing the in engagement with the bi-metal disk [9 by a heat transfer to such a bi-metal thermostat to coiled spring 21. One end of the spring 21 enpermit the use of larger temperature differengages a washer 30 on the bushing 22 and the tials for the bi-metallic thermostat element. 2 other end engages a shoulder 28 in the base mem- It is also an object of the invention to provide her l4. A movable contact member 25 is loosely an improved control apparatus employing a bimounted on the bushing 22 and is in engagement metal thermostatic element which has improved with one end of a coiled spring 24. A second heat transfer characteristics and which may be shoulder 26 is provided on the bushing 22 and adjusted without disturbing the means which 30 engages the movable contact member 25 when provide the improved heat transfer characterthe switch mechanism is in the closed circuit istics. position. Two stationary contacts 29, shown in These and other objects are effected by my Figs. 1 and 2, are mounted on the base member invention as will be apparent from the following l4. Terminals 3| extend through the base memdescription and claims taken in connection with her I4 and are connected to conductors 32. A the accompanying drawing, forming a part of rubber cap 33 may be clamped over the hermetithis application, in which: cally sealed casing II to protect the terminals 3| Fig. 1 is a sectional view of my improved conand provide an opening for the conductors 32. trol mechanism taken on the line II of Fig. 2 I have shown my invention as applied to and includes a diagrammatic view of a domestic domestic refrigerating machines in which a morefrigerator having my improved control mechator 34 drives a compressor 35 to compress renism applied thereto. frigerant and condense the same in a condenser Fig. 2 is a sectional view of my improved con- 36 cooled by a fan 31. The condensed refrigertrol mechanism taken on line IIII of Fig. 1; ant is delivered through a conduit 38 to an evapoand, rator 39, a portion of which is shown in Fig. 1, Fig. 3 is a detail view of one of the supports any suitable expansion device (not shown) being for the snap-acting thermal elements shown in disposed between the condenser 36 and the evapo- Figs. 1 and 2. rator 39. vaporized refrigerant is returned to Referring specifically to the drawing for a th compress r hro h a c nduit 4 The condetailed description of my invention, numeral ll ductors 32 connect a source of power L1, L2 to designates a hermetically sealed casing containthe switch terminals 3| and to terminals 42 ing a control mechanism generally designated at on the motor 34. The bi-metal thermostatic elei2. The hermetically sealed casing II embodies ment l9, therefore, opens and closes the circuit a heat conducting cover member 13, preferably to the motor 34 in response to the temperature formed of a metal such as copper or brass and an of the evaporator 39, the heat conducting cover I3 of the casing II providing for the passage of heat between the evaporator 39 and the bi-metal disk I9.

In accordance with my invention, each finger I8 is provided with a spring member 44 formed of a good heat conducting material, such as phosphor-bronze, and so positioned that it will contact with the metal heat conducting cover I3 when the cover I3 is in its assembled position on the base I4. The phosphor-bronze springs 44 provide increased heat transfer from the evaporator 39 to the interior of the sealed control mechanism I2 and to the bi-metal disk I9. By

increasing the heat transfer from the evaporator 39 to the bi-metal disk I9 it is possible to use a bi-metal disk with a wide temperature differential because the amount of heat transferred to the bi-metal disk or abstracted from the bi-metal disk is much greater than in a case where the air or gas within the casing II is depended upon entirely for transferring heat to and from the bi-metal disk I9.

The temperatures of the evaporator 39 at which the bi-metal disk I9 respectively opens and closes the contacts 25, 29 may be varied substantially independently of each other. If it is desired to change the temperature of the evaporator 39 at which thebi-metal disk I9 closw the contacts, the shaft I1 is screwed into or out of the tapped metal bushing I6 so that the stop is moved either towards or away from the disk I9. When the disk I9 snaps to the open contact position (not shown) the center of the disk engages the stop 20. Therefore, if it is desired to raise the temperature of the evaporator 39 at which the disk I9 will snap to close the contacts 25, 29 the stop 20 is positioned closer to the disk I9 so that when the disk is in the open contact position its internal stress will be increased, mechanically and less of a temperature change will be required to snap the disk. On the other hand, if it is desired to lower the temperature at which the evaporator 39 will snap the disk I9 to the closed contact position, the stop 20 is positioned further away from the disk I9 so that the stress in the disk I9 due to mechanical force, when in the open contact position, is lessened and a greater temperature change will be required to snap the disk to the closed contact position.

When it is desired to vary the temperature at which the contacts 25, 29 are opened, the position of the bi-metal disk I9 relative to the bushing 22 is changed by moving the disk I9 bodily in notches-15 provided in the fingers I8. Fbr example, if it is desired to decrease the temperature at which the disk I9 opens the contacts 25, 29 from that shown in Fig. 1, the disk I9 is bodily moved to notches nearer the bushing 22 in fingers I8. The internal stresses in the bi metal disk I9 are, therefore, increased mechanically and thus a reduction in the temperature of the disk I9 and the evaporator 39 is required to open the contacts 25, 29. On the other hand, if the bi-metal disk I9 is moved to notches more remote from the bushing 22, the internal stresses in the bi-m'etal 'disk I9 are decreased and the temperature necessary to open the contacts 25, 29 will be lower. Since the bushing 22 is always in contact with the center of the disk I9, as the disk I9 is moved in the notches 45, the'shoulder 23' of bushing 22 remains stationary so that only the edges of the disk 19 are moved, with the result that the disk assumes either a flatter position or a more concave position. It may then be necessary to change the position of the sto 20 to compensate for the change in position of the disk I9 in the notches 45, if it is desired to maintain the contact closing temperature the same. When the disk I9 is adjusted in the manner aforesaid, then only the temperature at which the evaporator 39 effects opening of the contacts 25, 29 is changed.

It will be apparent that the adjustments of the control may be made before the control is sealed and that the contact between the casing II and the phosphor-bronze springs 44 does not affect the manual adjustments of the control after the cover member I3 and the base member I4 are assembled.

If desired, the hermetically sealed casing II may be evacuated through a conduit 46 after which the casing II is preferably filled with inert gas such as nitrogen and the conduit 46 In order to effect a complete hermetic seal,

the base member I4 is provided with an annular notch 41 in which a gasket 48 of a resilient material such as rubber is disposed. The metal cover I3 is then disposed in its position on the base I4 and the edge thereof is rolled inwardly and downwardly, as shown at 49, by any suitable tool. This provides a very inexpensive method of hermetically sealing the casing II and also facilitates opening the casing for repairs, after which the cover I3 may be re-rolled to again provide a hermetic seal.

The control mechanism described, except for the addition of the phosphor-bronze springs 44, is completely disclosed and claimed in the copending application of Roger W. Hastings, Serial No. 260,517, filed March 8, 1939 for improvement in Control apparatus.

From the foregoing it will be apparent that I have provided an improved control mechanism .of the bi-metal thermostatic type wherein a wide differential bi-metallic element may be utilized and wherein metal to metal contact between the thermostat and the casing is eifected and the cont;'ol mechanism may be adjusted prior to assembly of the enclosing casing.

While I have shown my invention in but one 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 placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. A switch structure embodying electrical contacts, a snap-acting bl-metal thermostat for opening and closing said contacts in response to changes in temperature, a plurality of supporting members for retaining said bi-metal thermostat in snap-acting position, a casing structure formed of separable members for enclosing said bi-metal thermostat, supporting members and contacts, said casing structure embodying at least a portion formed of a material of relatively high heat conductivity, and heat conductin means extending between at least some of said supporting members and the casing portion of relatively high heat conductivity, said casing portion of relatively high heat conductivity freely engaging said heat conducting means.

2. A switch structure embodying a casing comprising separable members, electrical conheat in a direct metallic path between the object or media exterior of the casing and the bi-metai thermostat, said last means being so arranged that when said casing is separated the adjustment of the bi-metal thermostat remains unchanged.

GERALD P. MARCY.

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