US3448918A - Discharge gas manifold construction for hermetic refrigerant compressor - Google Patents

Description

June 10, 1969 R. E. CAWLEY 3,448,913

DISCHARGE GAS MANIFOLD CONSTRUCTION FOR HERMETIC REFRIGERANT COMPRESSOR Filed Oct. 23, 1967 :Sheet of 2 l f' O 2 i '76; 8 l: 38 1 28 Z 214 49 76 72 73 50 342 30 'I .36 v 43 INVENTOR. R; aha rdE (azaley BY 0% K g Ms,

J1me 1969 R. E. CAWLEYY 3,448,

DISCHARGE GAS MANIFOLD CONSTRUCTION FOR HERMETIC REFRIGERANT COMPRESSOR Filed Oct. 25, 1967 Sheet 2 of 2 m J0 7 g ifli T H I INVENTOR.

Call/la y Mun United States Patent 3,448,918 DISCHARGE GAS MANIFOLD CONSTRUCTION FOR HERMETIC REFRIGERANT COMPRESSOR Richard E. Cawley, Hurst, Tex., assignor to Lennox Industries Inc. Filed Oct. 23, 1967, Ser. No. 677,385 Int. Cl. F04b 39/00, 35/04 US. Cl. 230-232 3 Claims ABSTRACT OF THE DISCLOSURE Summary 07 the invention This invention relates to a hermetic refrigerant compressor, and more particularly, to a hermetic refrigerant compressor having improved means for subdividing the discharge gas manifold so as to accommodate operation at full capacity or at reduced capacity without producing undesirable crankshaft bearing stress.

A refrigerant compressor having a common discharge gas manifold is desirable in terms of economy and simplicity. In Gerteis Patent 3,008,628 and Parker Patent 3,272,426 there are shown compressors of this type. At times, it is desirable to operate a refrigerant compressor at reduced capacity, especially compressors about 7 /2 tons or larger. In prior compressors having individual or paired discharge gas manifolds (and not a common annular discharge gas manifold formed about the compressor block) the discharge and suction sides could be readily interconnected since the individual or paired discharge gas manifolds were sealed from and independent from another. However, in a compressor having a common annular discharge gas manifold about the compressor block, as in Gerteis Patent 3,008,628 and Parker Patent 3,272,426, it is necessary to provide means for subdividing the discharge gas manifold so as to permit a part of the discharge gas manifold to be connected with the suction side of the compressor without impairing effective operation of other cylinders operatively joined to the remainder of the discharge gas manifold.

One arrangement proposed for subdividing the common discharge gas manifold is shown in Kropiwnicki Patent 3,315,880. Flanges are provided on each side of a selected cylinder or cylinders. The flanges extend transversely to the upper and lower annular flanges which, in cooperation with the exterior of the compressor block and the annular sleeve, define the discharge gas manifold. A shallow groove is provided in each of said flanges extending transversely to the annular flanges. A resilient seal is provided in each of said shallow grooves for effecting a seal about the selected cylinder or cylinders.

An object of the present invention is to provide an improved hermetic compressor having means for subdividing a common discharge gas manifold defined between a compressor block and an annular sleeve telescopically receiving such compressor block in a simple and effective manner, without producing undesirable unbalanced crankshaft loading factors.

Another object of the present invention is to provide a hermetic compressor of the type having a common discharge gas manifold defined between a pair of spaced annular flanges on the compressor block and an annular sleeve encircling the compressor block and sealingly engaged with said flanges, with a third annular flange between said pair of spaced annular flanges for subdividing the discharge gas manifold into two annular compartments, with some of the cylinders discharging into one compartment and with the remainder of the cylinders discharging into the other compartment so as to provide for substantially equal crankshaft bearing loading whether or not all cylinders are loaded. Other objects and advantages of the present inventionwill be made more apparent hereinafter.

Brief description of the drawing There is illustrated in the drawing a presently preferred embodiment of the present invention in which like numerals refer to like elements and in which:

FIG. 1 is a cross-sectional view of a hermetic refrigerant compressor embodying the present invention; and

FIG. 2 is a compressor block layout or development showing the subdivided discharge gas manifold arrangement of the present invention.

Description of the preferred embodiment Referring to FIG. 1, there is illustrated a hermetic refrigerant compressor embodying the present invention. The compressor 10 comprises a gas-tight outer housing including an upper shell 12 and a lower shell 13 integrally joined to one another as, for example, by welding. To the bottom of the exterior surface of the lower shell 13 are welded a plurality of legs'14, which are adapted to support the compressor 10 in an upright position.

Resiliently supported within the outer housing or casing of the compressor 10 by spring means 15 is a compression mechanism 16 which includes a compressor block 18 having an upper drive motor portion 20 and a lower crankcase portion 22.

Provided within the compressor block 18 are a plurality of radially-disposed cylinders 24. Although a four cylinder compressor is illustrated herein, it will be understood that the present invention may be used in a refrigerant compressor having two or more cylinders wherein at least one of the cylinders is adapted to be unloaded. Cylinder sleeves or liners 26 are provided in each of the cylinders 24 and a piston 28 is slidably and reciprocably mounted within each of the cylinder liners 26. Each piston 28 has mounted therein a wrist pin 30 upon which is journalled one end of a connecting rod 34. The other end of each connecting rod 34 is affixed to the eccentric portion 36 of a drive shaft or crankshaft 38 for actuating an associated piston upon rotation of shaft 38.

Provided at the end of each cylinder 24 and closing the end of the cylinder cavity are valve assemblies 42. Such valve assemblies may comprise a discharge valve unit 43, a suction valve plate 44 and a suction valve or reed member 45. The valve assemblies 42 are operative in a known manner for controlling the flow of gas to the discharge side from the suction side of the compressor.

Each valve assembly 42 is held in place in the end of a cylinder by a cylinder head or cap 48. A Belleville spring 49 and a retaining ring 50 cooperate with the head 48 to maintain the head in position closing the end of the cylinder.

The compression mechanism 16 includes an annular sleeve 52 which surrounds the compressor block and cooperates with the annulaar flanges 54 and 56 projecting from the block 18 to define .a discharge gas manifold 53 for receiving discharge gas from each of the cylinders 24. Resilient seals 55 and 57 are provided in shallow peripheral grooves in each of the flanges 54 and 56 for sealing between the flanges and the sleeve 52. Such seals are preferably O-rings made from neoprene or the like material.

In accordance with the present invention, a third annular flange 60 projecting from the compressor block 18 as provided between the first and second annular flanges 54 and 56 for subdividing the discharge gas manifold 53 into two compartments 58 and 59. A resilient seal 61 is provided in a shallow peripheral groove in flange 60 to seal the two compartments in the discharge gas manifold from one another. Seal 61 may be an O-ring made from neoprene or the like.

The drive shaft 38 is connected at its upper end to an electric drive motor 64 by suitable retaining means, for example, by a key or by shrinking the rotor of the motor 64 onto the upper end of the crankshaft 38. The motor 64 comprises a stator 65 which is fixedly supported within the motor portion of the compressor block 18. The stator 65 is inductively connected to the rotor 66 aflixed to the upper end of the crankshaft 38.

Enclosing the top of the motor 64 is an inverted cupshaped end cap 68 which is connected to the top of the motor portion 20 of the compressor block 18.

The shaft 38 is journaled within a lower bearing 70 which is mounted in the lower bearing head 71. The lower bearing head 71 is maintained in position by a suitable wedge lock or retaining ring 72 seated within an annular groove in the lower portion 22 of the compressor block 18. Also provided in the lower bearing head 71 is a thrust bearing 73 which has a central opening 74 defined therethrough. Located in the portion of the shaft 38 below the counterweight portion 75 is a coaxially-disposed hole which constitutes the eye of the impeller of the pump means which is formed within the crankshaft in a known manner.

The crankshaft 38 is journaled in the compressor block 18 intermediate its ends by means of the spaced bearings 76 disposed in the hub portion 77 fonmed in the partition wall 78 of the compressor block 18.

A heat shield 80 is provided concentrically about the annular sleeve 52 for preventing heat transfer from the relatively hot discharge gas in the discharge gas muflling chamber or manifold to the relatively cold suction gas entering the compressor between the compression mechanism and the outer housing.

A plurality of terminals 81 (two of which are shown) are provided in the top of the upper shell 12 of the outer casing in order to conduct electrical current from a suitable source to the motor 64 and to provide for connection of suitable motor protection means while preserving the hermetic nature of the compressor.

An unloader mechanism 82 is operatively connected to the discharge gas manifold to unload one or more selected cylinders in operation. The unloader 82 may be operated from a thermostat or it may be responsive to a suitable suction pressure control.

Suction gas enters the outer shell or housing of the compressor via suction inlet 83 and flows into a first compartment defined between the outer casing and the compression mechanism 16 below the flange 29 on the support member 28 for the resilient means 16. The gas passes through a second compartment or annular space defined between the flange 29 on the support member 28 and the flange 52a on the annular sleeve member 52 and then flows into a third compartment defined between the upper casing and the top of the compression mechanism 16. The gas passes from the third compartment through an opening 69 in the top of the motor cap or end cap 68 down over the electric motor 64 for cooling the motor. The suction gas passes from the motor compartment through openings 84 in the compressor block into the valve assemblies 42.

Gases discharged from each of the cylinders 34 pass through valve assemblies 42 into the discharge gas muffling space 53 defined between the flanges 54 and 56 of the compressor block and the annular sleeve 52. The discharge gases pass from the annular chamber or manifold 53 through a discharge pipe 87 into the expansion loop of the discharge line 88, which extends through the outer casing of the compressor 10 for conducting the discharge gas from the compressor to the condenser of a refrigerating system in a known manner. The unloader 82 of the present invention is adapted to be communicated to the two compartments 58 and 59 defined within the discharge gas manifold 53 for alternatively communicating the lower compartment to the upper compartment or for unloading the gases from the lower compartment into the space between the compression mechanism 16 and the outer housing.

Referring now to FIG. 2, there is illustrated a layout of the compressor block better illustrating the construction of the manifold subdividing means and the gas flow path through the discharge gas manifold 53. For convenience, the four cylinders of the compressor 10 illustrated has been designated 24a, 24b, 24c and 24d. The discharge gas manifold 53 is defined between the annular sleeve 52 and the adjacent portions of the compressor block 18 enclosed between the upper and lower flanges 54 and 56. As indicated by the arrows, discharge gas from the cylinders 24a and 24b pass into the upper compartment or chamber 58 defined between the intermediate flange 60 and the upper flange 54. Gas discharging from cylinders 24c and 24d pass into the lower compartment or chamber 59 defined between the intermediate flange 60 and the lower flange 56. The gases discharging from cylinders 24c and 24d pass through the restrictions 88 defined by ribs formed on the compressor block into the enlarged spaces between the restrictions and then into conduit 89 for passage to the unloader 82. If the unloader has been actuated so as to maintain full capacity, the gases flow back into the compartment 58 defined between the flanges 54 and 60. On the other hand, if the unloader has been actuated in response to a predetermined control so as to unload the cylinders 24c and 24d, then the gas will be discharged through the opening 83 for intermingling with the suction gas between the compression mechanism 16 and the outer housing.

The discharge gases issuing from cylinders 24a and 24b pass through restrictions defined by ribs projecting from the compressor block 18 and by the cylinders into enlarged passages defined within the compartment 58 between the flanges 54 and 60 for mufliing the discharge gas. These gases pass from the compartment 58 defined between the flanges 54 and 60 into the discharge line 87.

It will be understood that the illustrated embodiment of the invention provides for a 50 percent reduction in capacity since two of the four cylinders may be unloaded at one time.

As will be noted from the development of FIG. 2, cylinders on opposite sides of the axis of the crankshaft remain operative when the compressor is operating at reduced capacity, while the other opposed cylinders are unloaded. Specifically, cylinders 24a and 24b remain loaded when cylinders 24c and 24d are unloaded. By this arrangement unequal crankshaft loading is obviated. Subdividing the discharge gas manifold 53 through use of an annular flange disposed substantially parallel to the upper and lower flanges defining the discharge gas manifold provides for the desired compartmentized discharge gas manifold without unduly complicating assembly of the compressor block into the telescoping annular sleeve 52.

While I have described a presently preferred form of the invention, it will be understood by those skilled in the art that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

What is claimed is:

1. In a hermetic compressor of the type including an outer casing, compression means in said casing comprising a compressor block telescopically received in a housing sleeve, said block having first and second annular flanges projecting therefrom and engageable with the inner surface of said sleeve to define in cooperation therewith a.

5 substantially annular discharge gas manifold, a plurality of radially-disposed cylinder means in said block opening into said discharge gas manifold, a plurality of radiallydisposed cylinder means in said block opening into said discharge gas manifold, a crankshaft rotatably journalled in said block, a piston slidably received in each cylinder and operatively connected to said crankshaft, a suction gas manifold, and valve means operatively communicating the suction gas manifold with the discharge gas manifold, the improvement characterized by a third annular flange projecting from the compressor block, the third flange being disposed between the first and second flanges for subdividing the discharge gas manifold into first and second compartments, at least one cylinder means communicating with said first compartment and the remainder of said cylinders communicating with said second compartment, passage means connecting said first and second compartments and unloader means in said passage means for alternatively (1) bypassing gas passing from the first compartment to the second compartment to unload the cylinder means discharging into the first compartment or (2) allowing flow of gas from the first compartment to the second compartment to maintain said cylinder means discharging into said first compartment loaded.

2. A device as in claim 1 wherein an annular groove is provided in the periphery of said third flange and a resilient seal is provided in said groove for sealing between said third flange and the inner surface of said sleeve.

3. A device as in claim 1 wherein the unloader means bypasses gas into the space between the compression means and the outer casing.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner.

U.S. Cl. X.R. 230-58

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