US2192852A

US2192852A - Control for refrigerating apparatus

Info

Publication number: US2192852A
Application number: US294613A
Authority: US
Inventors: Roger W Hastings
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1939-09-13
Filing date: 1939-09-13
Publication date: 1940-03-05
Anticipated expiration: 1957-03-05

Description

March 1940- R. w. HASTINGS 2,192,852

CQNTROL FOR REFRIGERATING APPARATUS Original Filed April 30, 1957 INVENTOR Rose/e 0/. Has T/Mss. J I

29 O mfg; I

V ATTOR EY Patented Mar. 5, 1940 PATENT OFFICE CONTROL FOR REFRIGERATING APPARATUS Roger W. Hastings, Springfield, Mass., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Continuation of application Serial No. 139,873,

April 30, 1937.

This application September 13,

1939, Serial N0. 294,613

11 Claims.

My invention relates to control apparatus for refrigerating machines and it has for an object to provide improved apparatus of this kind. This application is a continuation of my application Serial No. 139,873 originally filed April 30, 1937.

A further object of the invention is to provide a compact control mechanism that is inexpensive to construct and which may be readily applied to various forms of refrigerating machines.

It is a further object of the invention to provide an improved refrigerator control employing a snap-acting thermal device that may be readily adjusted to maintain different refrigerating temperatures.

A still further object of the invention is to provide an improved control mechanism for a refrigerating element including a hermetically-sealed switch structure which may be readily adjusted to a plurality of positions wherein the element is maintained at different temperatures and including a position wherein the element is rendered inactive for cooling.

' 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:

Fig. 1 is a diagrammatic view of a domestic refrigerator having my improved control mechanism applied thereto;

Fig. 2 is a sectional view in a vertical plane through the control mechanism shown in Fig. 1 and viewed from the same point as Fig. 1; and,

Figs. 3, 4 and are sectional views taken along the lines IIIIII, IV--IV and V-V of Fig. 2,

- respectively.

Reference will now be had to the drawing for a description of the invention. In Fig. l, I have shown a conventional domestic refrigerator cabinet having "a compartment formed therein for food to be refrigerated. An evaporator I2 is disposed for cooling the air in the compart-. ment H and may be provided with shelves l3 for supporting trays I4 in which fluid to be cong'ealed is contained. Refrigerant is circulated through the evaporator |2 by a refrigerant condensing unit shown generally at l5 and including a compressor l6, driven by an electric motor I1, and a condenser 18. The latter is cooled by a fan l9 that is preferably motor-driven as shown. Vaporous refrigerant is conveyed from the evaporator |2 through a suction conduit 2| and the compressed gas is conveyed to the. condenser |8 through a conduit 22. Liquefied refrigerant passes through a conduit 23 to the evaporator l2 and is controlled by any suitable expansion device, such as, for example, a conventional high side float valve 24. p

The compressor motor |l receives electrical energy from a suitable source shown as line conductors L1 and L2. Conductors 25 and 26 connect the motor I! to the conductors L1 and L2 as shown; the conductor 26 having my improved control device 21 connected therein. The device 21, as described hereinafter, includes provisions for starting and stopping operation of the compressor |6 and motor H in response to predetermined high and low temperatures of the evaporator I2. The apparatus described heretofore operates on the well-known compressor-condenser-expander cycle and it is deemed unnecessary to describe in detail the operation thereof.

Reference will now be had to Figs. 2 to 5, inclusive, for a detailed description of the device 2'! shown in Fig. 1. The latter includes a cylindrical casing 28 having mounting ears 29 that are strapped or otherwise suitably secured to the evaporator l2, a portion of which is shown in Figs. 2 and 4. The casing 28 includes an end wall 30 and is closed at its other end by a wall 3| having a flexible portion shown, by way of example, as an expansible bellows 32. The latter is soldered or otherwise suitably affixed to the wall 3| to provide a gas-tight connection at 3|a. The wall 3| is soldered or otherwise connected to the casing 28 to provide a gas-tight connection at 3|b. The casing 28 and the flexible wall 3| define a hermetically-sealed chamber 33. for housing a switch 34 and a thermal responsive disc 46, to be referred to more in detail hereinafter. The soldered connection at 3|b is spaced from the disc 45 so that the latter will not be affected by heat when the wall 3| is afiixed to the casing 28. This is a desirable feature of my control construction as'thermal elements of the type shown may have their temperature characteristics seriously affected if subjected to a high temperature.

The switch 34 includes a stationary and a

movable contact

35 and 36, respectively, for controlling energization of the motor ll. Support for the stationarycontact may be provided by a rigid conductor 31 that extends through a pair of gastight insulating seals 38 in the wall 3|. One portion of the conductor 26 is connected to the conductor 31 as shown at 39. The movable contact 36 is carried by a spring 4| that biases the contact 36 toward the contact 35 and which may include laterally-extending portions 42 secured to a conducting strip 43, the latter extending through gas-tightinsulating seals 44 in the wall The other portion of the conductor 26 is connected to the strip 43 as shown at 45. I have shown four seals passing through the wall 3| so that a convenient support for the

contacts

36 and 35 may be obtained and for increasing the current-carrying capacity of the seals, but it will be understood that two insulating seals may be employed if desired for conducting the current to the contacts of the switch.

The switch structure 34 is actuated by the thermal responsive element or disk 46, substantially circular in shape and of bi-metal construc- This type of element is Well known in the art and operates in a snap-acting manner when subjected to predetermined temperatures. As shown in Fig. 4, the disk 46 is in its switch closing position. When the temperature of the disk 46 is depressed to a predetermined value, it snaps to the position shown in broken lines and thereby moves the switch 34 to its open posi tion. The disk 46 is disposed within the portion of the chamber 33 adjacent the evaporator |2 so that it quickly reflects changes in temperature of the evaporator 2. clamped in place at its periphery by a plate 41 and crimps 48 in the casing 28, as shown.

The disk 46 carries a socketed fitting 49 that is slidably supported by the plate 41. An insulat ing switch actuating yoke 5| is maintained in engagement with the socketed fitting 49 by a spring 52, the latter bearing against the inside of the flexible bellows 32. An opening 53 is provided in the yoke 5| through which the contact carrying spring 4| extends. As the disk 46 snaps to the position shown in broken lines, the side wall of the opening 53 engages the spring 4| and moves it sufficiently to disengage the contact 36 from the contact 35. The lost motion provided by the spring 4| and opening 53 assures good contact between the

contacts

35 and 36 when closed.

As. shown in Fig. 2, a pinch tube 54 may be the capacity of the switch increased.

In order to vary the temperatures to which the disk 4'6 responds to open and close the contacts, I provide an operators adjustment as shown generally at 55. This adjustment includes a cam 56 carried by a shaft 51 that is journalled in a cap 58., the latter being fixed to the casing 28 as described hereinafter. An adjusting handle or knob 59 is secured to the shaft 51 and is readily accessible to the operator as is apparent from Fig. 1. Temperature readings or other indicia may be indicated on a plate 6| carried by the casing 28 and readable in conjunction with a pointer on the knob 59.

The cam 56 engages a seat 62 that bears against the bellows 32, the seat 62 having slots 83 formed therein through which the shaft 51 projects. The seat 62 includes a projection 64 that registers with depressed portions 65 to 69, inclusive, formed in the cam in the various positions of the latter. When the depression 65 is in registry with the projection 64, the bias of the spring 52 is at a minimum, and, accordingly, the temperature of the evaporator l2 to which the disk 46 responds to close the switch 34 is relatively low. Therefore, in. this position of the cam 56, the switch is operated to maintain the evaporator 2 at its lowest value. Rotating the cam counter-clockwise as viewed in Fig. 2 increases the bias of the spring 52 and increases The disk 46 may be the temperatures of the evaporator to which the disk 46 responds to The evaporator I2 is maintained at its maximum operating temperature when the projection 64 is disposed in the depression 68 on the cam.

A position of the cam is provided in which the switch 34 is maintained open at which time the condensing unit I5 is rendered inactive. In this inactive or off position, the depression 69 in the maximum raised portion of the cam engages the projection 64. In this position, the end of thebellows 32 engages the adjacent end of the yoke 5| and moves the yoke to the left a sufiicient distance to maintain the switch 34 open, regardless of the temperature of the disk 46.

The cap 58 is made adjustable with respect to the casing 28 in order that a preliminary, or factory adjustment may be given to the spring 52, independently of the operators adjustment 55. This adjustment is desirable for determining the temperature to which the control responds in the different positions of the operators adjusting mechanism 55. As shown, I provide a connection 58 and the casing 28 which permits axial movement of one of these elements with respect to the other. The casing may be provided with a slot through which a binding screw 12 extends, the screw 12 being threaded in the cap 58. Accordingly, the cap 58 may be moved inwardly or outwardly with respect to the casing 28, whereby more or less bias is imparted to the spring 52. When the proper bias is obtained, the screw 12 is tightened for binding the cap 58 to the casing 28.

As shown in Figs. 2 and 3, the conductor 26 extends through a bushing 13 in the cap 58. The latter may be slotted as shown at 14 for the reception of the bushing 13 whereby the connection of the conductor portions 26 to the loop 38 and strip 43 may be readily made and the cap 58 slide over the bushing 73 during its assembly to the casing 28.

From the foregoing, it will be apparent that I have provided an improved control mechanism having a sealed-in switch mechanism, which control mechanism may be readily assembled to a refrigerant evaporator. The heat responsive disk and sealing bellows are alined for the sake of compactness and the adjusting shaft 51 of the operators adjustment 55 is arranged at right angles to the axis of the bellows and disk so that the adjusting handle 59 may be disposed at the front of the evaporator where it is accessible. Furthermore, I have provided, in a control of this type, an adjusting mechanism movable to a plurality of selective positions in which various evaporator temperatures are maintained and including a position wherein the condensing unit is inactive for cooling.

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. In a control mechanism, the combination of a casing structure having a flexible wall and defining a hermetically-sealed chamber, a switch disposed within the chamber, a thermal-responsive element subjected to temperature for actuating the switch, a spring providing a bias upon close and open the switch 64] the thermal-responsive element and the flexible wall and determining the temperatures at which said element operates, and means for adjusting the bias of the spring and movable to a plurality of positions wherein the thermal-responsive element actuates the switch at different temperatures, said adjusting means including a rotatable device, the axis of which is disposed at an angle to the direction of movement of saidthermal-responsive element.

2. In a control mechanism for a refrigerating machine, the combination of a casing structure having a flexible wall and defining a hermeticallysealed chamber, a switch disposed within the chamber for controlling the operation of the refrigerating machine, a thermal-responsive element subjected to the temperature produced by the refrigerating machine for actuating the switch, a member connecting the thermal-responsive element and the switch for imparting movement of the former to the latter, a spring biasing the thermal-responsive element to one of its positions and engaging said flexible wall, and adjustable means disposed exteriorly of the casing in engagement with the flexible wall, and being movable to a plurality of selective positions for varying the bias of the spring and the temperatures at which the thermal-responsive element operates the switch, said adjustable means being adjustable to a position wherein it eiIects engagement of the flexible wall and said connecting member whereby the former moves the latter sufiiciently to effect opening of the switch independently of the thermal-responsive element.

3. In a control mechanism, the combination of a casing structure having a flexible wall and defining a hermetically-sealed chamber, a switch disposed within the chamber, a thermal-respom sive element subjected to temperature for actuating the switch,.a spring engaging the flexible wall and biasing the thermal-responsive element toward its switch open position, and adjustable means engaging the flexible wall for varying the bias of the spring whereby the temperatures at which the thermal-responsive element operates the switch are varied, said adjustable means being movable to. a position wherein the flexible wall engages the thermal-responsive element and forces it to a position wherein the switch is maintained open regardless of the temperature of the thermal-responsive element.

4. In a control mechanism for electrically-controlled apparatus, the combination of a casing, means for securing the casing to the apparatus, a thermal-responsive element carried by the casing in heat transfer relation with the apparatus, a switch hermetically sealed within the casing and actuated to open and closed positions by the thertrial-responsive element, a spring biasing the thermal-responsive element toone of said positions, a cam rotatable to a plurality of selective positions for varying the bias of said spring, a bellows for sealing said casing and interposed between the switch and the cam, means for rotatably supporting the cam, means for adjusting the cam supporting means relative to the spring, and a readily accessible device for rotating the cam, whereby the bias of the spring and the temperatures at which the thermal-responsive device actuates the switch are varied at will.

5. In a control mechanism for electrically-controlled apparatus, the combination of a casing, means for securing the casing to the apparatus, a thermal-responsive element carried by the casing in heat transfer relation with the apparatus,

a switch hermetically sealed within the casing and actuated to open and closed positions by the thermal-responsive element, a spring biasing the thermal-responsive element to one of said positions, adjustable means for varying the bias of the spring and including a rotatable member, the axis of which is disposed at an angle to the axis of the thermal-responsive device, a bellows sealing said casing and interposed between said switch and the adjustable means and a readily accessible handle for actuating the adjustable means so that the bias of the spring and the tem peratures at which the switch member is actuated to open and closed positions may be varied at will.

6. In a control mechanism for electrically-controlled apparatus, the combination of a casing structure having a flexible wall and defining a hermetically-sealed chamber, means for securing, the casing to the apparatus, a thermally actuated disk arranged within the chamber in heat transfer relation with the apparatus, a switch actuated in a snap-acting manner by the disk to open and closed positions in response to predetermined low and high temperatures of the apparatus, respectively, a spring disposed between the disk and .said flexible wall for determining the temperatures at which the disk actuates the switch, said switch and spring being disposed within the hermetically sealed chamber, means disposed exteriorly of the casing and engaging the flexible wall for adjusting the bias of the spring, said adjusting means including a rotatable element, the axis of which is arranged at an angle to the axis of the disk and a handle carried by said rotatable element for adjusting the same at will.

7. The combination as claimed in claim 6 including means for adjusting the bias of the spring independently of said rotating element.

8. In a control mechanism for electrically-controlled apparatus, the combination of a cupshaped casing having one end thereof secured in heat transfer relation with the apparatus, a wall closing the other end of the casing and secured thereto to provide a hermetically-sealed chamber, said wall having a flexible portion, a thermalresponsive element secured to the casing and disposed within said chamber at the end thereof remote from said wall, a switch disposed within the chamber and actuated by said element for controlling said apparatus and adjustable means cooperating with said flexible wall portion for varying the temperatures at which the thermal element actuates the switch.

9. In a control mechanism for electrically-controlled apparatus, the combination of a substantially cylindrical casing having an end wall secured in heat transfer relation with the apparatus, a wall having a flexible portion and secured by the fusion of metal to the end of the casing remote from said first end wall, whereby a hermetically-sealed chamber is defined within the casing, a snap-acting thermal-responsive disk secured to the casing adjacent the first-mentioned end wall and disposed within said chamber, a switch for controlling the apparatus and actuated by said disk, means for providing a bias on said disk for determining the temperatures to which it responds to operate the switch, said biasing means bearing against the inside of said flexible wall portion and means bearing upon the outside of the flexible wall portion for adjusting the bias of the biasing means whereby said temperatures may be varied at will.

1Q. The combination as claimed in claim 9 having a second means for adjusting the bias of the justable means cooperating with the flexible wall biasing means independently of said first adjustfor varying the bias of the resilient means on the ing means. thermal-responsive element, whereby the tem- 11. In a. control mechanism, the combination peratures at which the thermal-responsive eleof a casing structure having a flexible wall and ment operates the switch are varied, said addefining a substantially enclosed chamber, a justable means being adjustable to a position switch disposed Within the chamber and having where the switch is maintained in one of its poopen and closed positions, a thermal-responsive sitions regardless of the temperature of the ther element for actuating the switch, resilient means mal-responsive element. cooperating with the flexible wall for applying a i v bias to the thermal-responsive element and ad- ROGER W. HASTINGS.