Refrigeration apparatus

March 14, 1950

2,500,751

G. A. HALFVARSON

REFRIGERATION APPARATUS

Filed May 19, 1947

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Patented Mar. 14, 1950

2,500,751

UNITED STATES PATENT OFFICE

2,500,751

REFRIGERATION APPARATUS

Gustaf A. Halfvarson, Springfield, Mass., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania

Application May 19, 1947, Serial No. 748,936

Claims. (Cl. 230—208)

This invention relates to motor-compressor units and more especially to enclosed units of this type.

It is an object of the invention to provide novel means for cooling an enclosed motor-compressor unit.

It is another object of the invention to provide novel means for circulating a heat-absorbing fluid over the motor and compressor of an enclosed unit.

It is a further object to provide novel means for conducting the heat from the motor, the compressor, and the cooling fluid of an enclosed motor-compressor unit to the enclosure of the unit.

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 drawings, forming a part of this application, in which:

Fig. 1 is a horizontal cross-sectional view of an enclosed motor-compressor unit embodying the invention; and

Fig. 2 is a view on the line H—H of Fig. 1.

Figure 3 is a detail view of a portion of the heat-conducting band.

In the drawings, the reference numeral 10 designates the casing of a motor-compressor unit such as is used in domestic mechanical refrigerators. The casing 10 comprises the lower cup 12 and a cover 14 therefor welded to the cup 12. The lower portion of the side wall of the cup i 2 is provided with fins 16 for conducting heat from the cup 12 to the ambient atmosphere. A motordriven compressor unit 17 is supported in the cup 12 on resilient springs 18. The unit 17 comprises a lower cup-shaped casting 20 and an upper cup-shaped casting 22 secured to the lower casting 20. A motor stator 24 is pressed into the upper casting 22 and carries the stator windings

26. The upper casting 22 is provided with an upper bearing 28, and the lower casting 20 with a lower bearing 30 in which bearings 28, 30, a shaft 32 is journaled. A motor rotor 34 is secured to the shaft 32 between the two bearings 28 and 30 and carries an overhanging crankarm 36 and crankpin 38 at its upper end. A compressor cylinder 40 is secured to the upper surface of the upper casting 22 and contains a reciprocating piston 42 actuated through a connecting rod 44 by the pin 38. The refrigerant vapor enters the casing 10 through a duct 45 and then passes through an inlet duct 48 into the valve chamber 46 of the compressor, is compressed, and forced from the casing 10 through a conduit 50.

The lower portion of the cup 12 forms an oil sump 54 which normally is filled with oil to the level of line 56. An oil pump 58 is located on the lower surface of the casting 20 and is formed by ⁵ three metal discs 62, 63, and 64 held in place by bolts 65. The upper disc 62 has a central opening 66 into which the bottom of the shaft 32 extends. Also in the central opening 66 is a paddle-type impeller wheel 67 which is driven by the shaft

32. The middle disc 63 and the lower disc 64 support the weight of the shaft 32 and also provide two ducts 68 and 70. Duct 68 communicates with the oil in the oil sump 54 and with the central opening 66 at a location near the hub of the 15 impeller 67. The other duct 70 communicates with the central opening 66 at an area adjacent the periphery of the impeller 67 and with a central duct 74 in the crankshaft which runs longitudinally therethrough and at an angle through 20 the crankarm 36 and the crankpin 38 and emerges on the upper face of the crankpin 38. When the motor 24,34 is in operation, the oil pump 58 forces oil through the duct 74, through the crankpin 38 and sprays it upward in a conical spray, as indi25 cated by the arrows 76 in Figure 1. Lateral ducts 78 and 80 also conduct some of the oil to the crankpin bearing and the motor bearings 28 and 30, respectively. A bleeder duct 69 connects with the opening 66 in the upper disc 62 and leads 30 upwardly to an upper portion of the oil sump 54.

This duct 69 allows refrigerant vapor bubbles which may be present in the pump 58 to escape.

The oil spraying from the upper end of the duct 74 strikes the cover 14, the compressor 40, 46, 35 and the upper casting 22 and runs downwardly along the inner wall of the casing 10 and the surfaces of the compressor 40, 46 and the upper casting 22 and returns to the sump 54. In so doing, the oil absorbs heat from the compressor 40 40, 46 and the upper casting 22 of the motor and transfers heat to the inner wall of the casing 10.

A metallic heat-conducting band 82 is located in the path of the down-flowing oil between the casting 22 and the finned area of the cup 12. This 45 heat-conducting band 82 is formed of thin spring steel stock and is divided into panels by oppositely located cuts 84, as best shown in Fig. 3. The cuts 84 each terminate in holes 86 which distribute the bending stresses when the band 82 is 50 bent. The band 82 thus consists of a series of flexible panels 85 connected by narrow neck portions 88. Three pins 90, equally spaced and secured to the band 82, engage holes 92 in the upper casting 22 to hold the band 82 somewhat loosely in 55 position. The band 82 is not pre-bent at the

2,500,751 neck portions 88 but assumes the polygonal shape shown in Fig. 2 when the unit is assembled, because of the greater flexibility of the neck portion 33 over that of the panels IS. The band S2 is so thin that it transmits little of the noise of the compressor 40, 41 and of the motor, 24, 34 to the casing 10. As a consequence, it also aids little in holding the unit in position in the casing

10, but does aid in damping out some of the periodic vibrations of the motor compressor unit

11.

Its chief function is to transmit heat by conduction from the upper casting 22 to the casing

10. It also retards the downward flow of the oil across it, so that the contact of the oil with the upper casting 22 and the cup 12 is prolonged to increase the heat transfer between the oil and the metal surfaces of the casting 22 and cup 12. The oil at the contact areas of the band 82 with the casting 22 and the cup 12 also aids in transferring heat from the casting 22 to the band 82 and from band 82 to the cup 12. In actual practice, a band of spring steel, .006 inch thick, has given good results where the outer diameter of the casting 22 is 6½ inches and the space between it and the cup 12 is &amp; inch. The band consisted of nine panels.

It will be apparent from the above that this invention provides for spraying oil from the crankpin of a vertical motor compressor unit, which oil then absorbs heat from the heat-producing portions of the motor compressor unit and transfers the heat to the casing thereof, from which it is transferred to the ambient atmosphere by cooling fins. The invention also provides a heat-conducting band which aids in transferring heat from the motor to the 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 other changes and modifications without departing from the spirit thereof.