US3465954A - Compressor supporting means - Google Patents

Description

P 1969 c. s. ELLIS 3,465,954

COMPRES 50R SUPPORTING MEANS Filed Aug. 11, 1967 FIG] g INVENTOR.

United States Patent O 3,465,954 COMPRESSOR SUPPORTING MEANS Charles B. Ellis, Fort Worth, Tex., assignor to Lennox Industries Inc., a corporation of Iowa Filed Aug. 11, 1967, Ser. No. 660,051 Int. Cl. F04b 39/00, 35/04 U.S. Cl. 230-235 5 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to hermetic refrigerant compressors of the type having compression mechanism resiliently supported within an outer casing and, more particularly, to a unitary mounting sleeve adapted to be disposed about the compression mechanism in such compressor so as to support the compression mechanism in spaced and vibration-free relationship. Further, the mounting sleeve is made of a material having low thermal conductivity so as to minimize heat transfer between the high and low temperature regions within the compressor and which will not break down rapidly in the refrigerant-oil environment within the compressor.

Heretofore, it has been known in the art to provide hermetic refrigerant compressors having compression mechanism resiliently supported within an outer casing by a plurality of springs. See, for example, Patent 2,855,139 granted Oct. 7, 1958. Other compressors have included an annular flange or support provided on the compressor block or on an annular sleeve connected to the compressor block and a separate flange secured to the interior of the casing. Helical springs, supporting pins, and bushings for the pins were connected between the flanges or supports for resiliently supporting the compressor block. The spring arrangements included several separate components and were often cumbersome and caused difficulties in assembly of the compressor.

Another problem with refrigerant compressors of the type described is that suction gas entering the space between the compression mechanism and the outer casing passed in heat transfer relationship with the discharge gas in the annular discharge gas cavity defined in the compression mechanism. This resulted in increased suction gas temperature entering the cylinders and in turn resulted in increased discharge gas temperature in the cylinders. Such increased discharge gas temperature resulted in accelerated oil breakdown, increased adverse chemical reactions and enhanced undesired copper plating on the valves. Furthermore, increased suction gas temperature will cause the suction gas to be less dense, resulting in lowering of pumping capacity. Also, increased suction gas temperature in the compression mechanism will increase the operating temperature and reduce the efliciency of the electric drive motor and shorten motor life. One solution to this problem was the provision of a metal heat shield disposed about the compressor block, as shown in Parker Patent 3,250,461 granted May 10, 1966. However, this required fabrication and assembly of a separate part.

An object of the present invention is to provide a mounting sleeve for a hermetic refrigerant compressor which will support the compressor block in spaced relationship to the outer housing without transmitting operating vibrations to the outer casing, which will, because of its low thermal conductivity, substantially minimize undesirable heat transfer between relatively cool incoming suction gas and relatively hot discharge gas in the annular discharge gas cavity defined in the compressor block, and which will also, if desired, provide an upper reservoir for storage of some of the oil charge in the compressor.

Another object of the present invention is to provide a unitary mounting sleeve and heat shield which will obviate the need for a plurality of separate mounting springs and a separate heat shield. Other objects and advantages of the present invention will be made more apparent hereafter.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the invention is shown in the accompanying drawing, in which:

FIGURE 1 is a cross-sectional view, with part broken away, of a hermetic refrigerant compressor embodying the integral compression mechanism support and heat shield means of the present invention; and

FIGURE 2 is a plan view, with part broken away of the integral compression mechanism support and heat shield means of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGURE 1, there is illustrated a refrigerant compressor embodying the present invention. The compressor comprises a gas-tight housing formed by an upper shell 10 and a lower shell 11 which are cupshaped and are joined by welding or the like. To the bottom of the exterior surface of the lower surface of the shell 11 are welded a plurality of legs 12 by means of which legs the compressor may be supported in an upright position in a condensing unit or an air-conditioning unit.

Compression mechanism, indicated generally by the numeral 14, are secured within the hermetically-closed outer housing. The compression mechanism illustrated is generally of the type shown in the copending application of Sidney A. Parker Ser. No. 587,005 filed Oct. 17, 1966, and reference may be made to said application for a fuller discussion of the detail of the compression mechanism. However, as will be apparent to those skilled in the art, the compression mechanism may be of the type including a cast compressor block, as shown, for example, in Patent 3,250,461 granted to Sidney A. Parker on May 10, 1966.

As seen in FIGURE 1, the compression mechanism includes a crankcase or compressor block assembly comprised of three concentric sleeves 16, 18 and 20. The sleeves are confined between upper and lower annular plate members 21 and 22 to which they are permanently secured, as by copper brazing.

Vertically supported within the crankcase assembly is a crankshaft 24. The crankshaft is journalled in an upper bearing 25 secured within an opening in the upper annular plate member 21 and a lower bearing 26 secured within an opening provided by the oppositely outwardly flared ends of plate members 27 and 28 that are jointly affixed to the lower annular plate member 22 by a retaining ring 30.

Radially disposed cylinder liners 32 are supported Within openings in the sleeves 18 and 20. Movable supported within the cylinder liners 32 are pistons indicated generally by the numeral 34. The pistons 34 are each connected to the eccentric portion of the crankshaft 24 by means of a connecting rod 36 and during rotation of the crankshaft, the pistons 34 will be reciprocated in the liners 32. A three-cylinder compressor is shown in the drawing. It will be apparent to those skilled in the art that the compressor can be provided with more or less cylinders, depending upon design requirements.

The crankshaft is operatively driven by electric motor 38. The stator 39 of the motor is affixed to the outer sleeve 20 and the rotor is joined to the upper end of the crankshaft for driving same.

The compression mechanism 14 is spaced from the outer housing so as to define an annular compartment or space for receiving suction gas returned to the refrigerant compressor through the suction inlet 41. The suction gas will pass through an opening 42 in the motor end cap 43 over the electric motor 38 to cool same and into the cylinders through opening 44 provided in the upper plate member 21. The pistons 34 will compress the gas and force it through the discharge gas cavity provided within the crankcase mechanism and out through the discharge line 46 in a conventional manner.

Disposed about the compression mechanism 14 is a unitary cup-shaped mounting and heat shield member 50. The member 50 performs a number of functions in the present design. The member 50 supports the weight of the compression mechanism resiliently within the outer housing and thereby obviates the need for helical spring arrangements as normally employed in refrigerant compressors to resiliently support the compression mechanism within the outer housing. The resilient mounting is necessary to minimize the vibrations carried from the compression mechanism to the outer housing. Vibration creates noise, and thus, the member 50 functions to minimize noise emanating from the compressor.

The member 50 further functions as a heat shield for minimizing heat exchange between the relatively hot discharge gas in the annular discharge gas cavity 46 within the compression mechanism 14 and the relatively cool suction gas in the space between the compression mechanism 14 and the outer housing. In use, it is found that undesirable increase in suction gas temperature entering the cylinders will in turn result in increased discharge gas temperature. The increase of the discharge gas temperature within the compression mechanism above desired levels resulted in accelerating the oil breakdown, increased adverse chemical reaction within the compressor and enhanced undesired copper plating on the valve. Increased temperature in the suction gas caused it to be less dense and resulted in lowering of the pumping capacity of the compressor. Since the suction gas is used for motor cooling, in the event the suction gas temperature increased, the operating temperature of the motor would increase and reduce the efficiency and shorten the life of the motor.

The member 50 is preferably molded from resilient material which has sufficient strength to bear the weight of the compression mechanism 14, and which material is relatively inert so as to withstand the chemical reaction of the refrigerant, which is commonly Freon and the oil Within the compressor. Among the materials from which the member 50 can be made are a synthetic rubber, as for example, neoprene, and a suitable plastic, as for example fluorinated polyolefin. The sides of member 50 are provided with recessed portions 51 for receiving the ends of cylinder liners 32.

The member 50 may be formed at its upper end with a thickened flange-like portion 52 having an annular recess 53 therein for defining an oil reservoir. The reservoir may be suitably connected by passage means within the compression mechanism for receiving oil from the crankshaft during operation so as to provide a supplementary storage for oil removed from Within the crankcase such that the flywheel portion of the crankshaft may be free to rotate with the level of lubricant lying below the lower level of the flywheel.

The member 50 is further formed with a plurality of projections 54 which space the lower end of the compression mechanism from the outer housing. A sump for lubricant (oil) is provided between the mounting sleeve and heat shield 50 and the outer housing in the lower portion of shell 11.

As seen in FIGURE 2, for example, there may be six projections 54 provided extending downwardly and outwardly from the member 50. It is also to be noted that the upper flange-like portion 52 has a plurality of peripheral recesses 56 therein for providing passageways for communicating the annular space between the compression mechanism and the outer housing below the flange 52 with the annular space between the motor portion of the compression mechanism and the outer housing above the flange 52. In addition, the member 50 has provision in the rear thereof for receiving the discharge tube 46 which is connected internally of the compressor to the discharge gas manifold. The recess 58 conforms generally to the shape of the discharge tube.

It is seen that by the present invention there has been provided a unitary mounting member and heat shield member for encircling the lower portion of the compression mechanism so as to resiliently support the compression mechanism within the outer housing and for minimizing heat transfer between the high and low temperature regions within the compressor. The member 50 is readily molded from a relatively inexpensive material. The material has a low thermal conductivity so as to minimize heat transfer between the relatively cool suction gas and the relatively hot discharge gas. Since the member 50 is resilient, it can be easily positioned over an assembled compression mechanism, even though the exterior configuration of the compression mechanism is not uniform and smooth. The compression mechanism with the member 50 carried thereon is then readily inserted into a lower casing member 11. The upper casing member 10 may then be positioned in place and the two components of the casing welded together to provide a hermetic enclosure for the compression mechanism. Fabrication of the compressor is thus facilitated.

While I have shown a preferred embodiment of the present invention, it will be understood by those skilled in the art that the invention is not so limited, since it may be otherwise embodied within the scope of the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a reciprocating compressor having an outer sealed casing, compression mechanism in said casing, means defining an annular discharge gas cavity in said compression mechanism, discharge line means for conducting discharge gas from said discharge gas cavity, and suction inlet means for introducing suction gas into the compressor, the improvement comprising a unitary mounting sleeve made from a non-metallic resilient material having low thermal conductivity disposed about the compression mechanism for supporting the compression mechanism in spaced relationship to the casing in a resilient vibration-free manner and for insulating incoming suction gas in the space between the compression mechanism and the casing from the discharge gas in the discharge gas cavity so as to minimize temperature increase of the suction gas prior to entry into the compression mechanism to improve compressor performance.

2. In a reciprocating compressor having an outer hermetically sealed casing, compression mechanism in said casing, means defining an annular discharge gas cavity in said compression mechanism, discharge line means for conducting discharge gas from said discharge gas cavity, and suction inlet means for introducing suction gas into the compressor, the improvement comprising a unitary mounting sleeve surrounding the compression mechanism for supporting the compression mechanism in spaced relationship to the casing in a resilient vibration-free manner and for insulating incoming suction gas in the space between the compression mechanism and the easing from the discharge gas in the discharge gas cavity so as to minmize temperature increase of the suction gas prior to entry into the compression mechanism to improve compressor performance, said compression mechanism including a compressor block and said mounting sleeve comprising a cup-shaped member engaging with the compressor block on the sides and on the bottom for resiliently supporting the weight of the compression mechanism.

3. A device as in claim 2, wherein a plurality of projections formed integrally with the mounting sleeve extend fiom the bottom of the mounting sleeve so as to space a major portion of the bottom of the mounting sleeve from the bottom of the interior of the casing.

4. A device as in claim 3 wherein the upper end of the mounting sleeve is formed with an integral enlarged flange having a recess therein defining a reservoir for References Cited UNITED STATES PATENTS 3,008,629 11/1961 Gerteis 23058 3,065,901 11/1962 Neubauer 230-58 3,315,880 4/1967 Kropiwnicki 230-58 ROBERT M. WALKER, Primary Examiner US. Cl. X.R. 230-6 8

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