US20070081910A1

US20070081910A1 - Compressor valve plate with spiral groove

Info

Publication number: US20070081910A1
Application number: US11/246,841
Authority: US
Inventors: Roy Butler; George Brandt; Thomas Palmore; John Wollitz; Babak Ranjbar
Original assignee: American Standard International Inc
Current assignee: Trane International Inc
Priority date: 2005-10-07
Filing date: 2005-10-07
Publication date: 2007-04-12

Abstract

A compressor includes a discharge and/or suction valve whose valve seat has a spiral groove that faces the valve. When the valve is closed, the spiral groove provides a minute fluid passageway between the valve and the valve seat. The spiral groove reduces fluid adhesion between the valve and the seat so that the compressor is quieter, more efficient and less expensive to make.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The subject invention generally pertains to reciprocating compressors and more specifically to valves and valve plates of such compressors.
2. Description of Related Art
To prevent backflow through a suction or discharge opening of a valve plate, compressors often use ring-type valves (similar in shape to washers) that can seal against the valve plate to cover the opening. In reciprocating compressors, the valves function as suction and discharge check valves that enable a reciprocating piston to compress the gas within a cylinder. The valves also determine which direction the gas flows through the compressor.
The sealing surface of the valve plate against which the valve seals is known as a valve seat. Typically, the surface finish of both the valve and the valve seat are ground as smooth as possible to ensure a positive seal between the two. Although a smooth finish may provide a tight seal, such a surface finish can create several problems. One, adhesion of a fluid such as refrigerant or oil trapped between the valve and the valve seat can cause the valve to stick and delay its opening, which can reduce the operating efficiency of the compressor. Two, the resulting delayed opening can make a compressor noisy. Also, a smoothly ground surface can be costly to produce.
Some compressors have something other than a smooth finish between the valve and the valve seat. The compressor disclosed in U.S. Pat. No. 1,718,350, for instance, has a series of concentric ridges on either the valve or its seat, thereby providing the valve with multiple seats for better sealing. Since the ridges are concentric, however, fluid can still be trapped within the concentric grooves that lie between the ridges. So even though such a design may provide better sealing, the design does not address the problem of liquid adhesion occurring between the valve and the valve seat.
U.S. Pat. No. 5,078,582 discloses a compressor whose valve seats have a roughened surface to quiet the operation of the valve. It is not clear, however, how the surface is roughened. If the surface is created by a distribution of pits, the pits may provide pockets that trap fluid in a manner similar to that of the grooves disclosed in the '350 patent just described. If the surface, however, is roughened by a series of protrusions, fluid passageways winding around the protrusions may provide relatively short leakage paths across the valve. Although a compressor designed according to the '582 patent may be quieter, such a compressor is not necessarily more efficient.
Consequently, a need exists for a compressor valve arrangement that is quieter, more efficient and less expensive than current valve arrangements.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a reciprocating compressor with a valve plate that includes a valve seat with a spiral groove to reduce the noise, reduce the manufacturing cost, and/or increase the efficiency of the compressor.
Another object of some embodiments is to provide a valve plate with a spiral groove so that when the valve is closed, the groove provides a minute fluid communication passageway between a cylinder and another chamber of the compressor.
Another object of some embodiments is to create a valve seat with a spiral groove that provides the valve seat with a surface finish of between 10 and 250 microinches.
Another object of some embodiments is to create a valve plate with an annular valve opening that is generally centered relative to a machined spiral groove in the valve seat.
Another object of some embodiments is to incorporate both a suction valve seat and a discharge valve seat in a common valve plate, wherein both seats include a spiral groove.
One or more of these and/or other objects of the invention are provided by a compressor that includes a valve plate, wherein the valve plate has at least one valve seat with a spiral groove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a compressor shown connected to a schematically illustrated refrigerant system.
FIG. 2 is an enlarged view of the encircled portion of FIG. 1.
FIG. 3 is an enlarged view of the encircled portion of FIG. 2.
FIG. 4 is a view taken along line 4-4 of FIG. 3 but with the suction valve and piston omitted.
FIG. 5 is a view taken along line 5-5 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A refrigerant system 10, shown in FIG. 1, includes a compressor 12 for compressing refrigerant gas and for forcing the refrigerant sequentially through a discharge outlet 14 of compressor 12, through a condenser 16 that releases heat for condensing the refrigerant, through an expansion device 18 (e.g., expansion valve, capillary tube, orifice, etc.) for cooling the refrigerant by expansion, and through an evaporator 20 for absorbing heat from an outside source or heat load. From evaporator 20, the refrigerant returns to compressor 12 via a suction inlet 22 to repeat the cycle.
Referring further to FIGS. 2 and 3, compressor 12 comprises a compressor housing assembly 24, which in this example includes a number of components including, but not necessarily limited to, a cylinder block 26, a cylinder head 28, a hermetically sealed shell 30, a discharge muffler 32, and other components of the compressor.
To compress the refrigerant, an electric motor 34 drives a piston 36 in reciprocating motion within a cylinder 38. A valve plate 40 provides a discharge valve seat 42 for a discharge valve 44 and a suction valve seat 46 for a suction valve 48. Additional components of the discharge valve assembly include a spider 50 attached to the face of valve plate 40, a center plug 52 attached to spider 50, and a spring 54 (e.g., a wave spring) that urges valve 44 against discharge valve seat 42.
Referring to FIG. 4, suction valve seat 46 comprises an inner seat 46 a and an outer seat 46 b that define an annular suction opening 56 between the two. Suction opening 56 provides a gas passageway that runs past valve seat 46. Suction valve 48 is a generally annular spring steel washer that is of a shape and size to overlie and cover suction opening 56. To hold valve 48 in place yet allow the valve to resiliently flex between a closed position against valve seat 46 and an open position spaced apart from seat 46, suction valve 48 includes two outwardly protruding tabs 58 that engage a curved upper edge of cylinder block 26. When the gas pressure differential between a suction chamber 60 and cylinder 38 is sufficient to force valve 48 away from valve seat 46 (as a result of piston 36 retracting or moving in a return stroke 62 within cylinder 38), valve 48 moves to its open position to uncover suction opening 56.
To minimize valve noise, to increase compressor efficiency, and/or to minimize the manufacturing cost of producing valve plate 40, the surface finish of suction valve seat 46 is produced by machining, turning or otherwise producing a spiral groove 64 on the face of valve plate 40. Groove 64 is laid out along a spiral pattern similar to that of a phonograph record, and the center of the spiral 66 is generally in line with the center of valve seat 46. Groove 64 preferably has an axial depth and a radial pitch that provides the face of the valve plate with a surface finish of about 10 to 250 microinches when measured along a radial path perpendicular to the groove. To avoid creating a short, direct leak path between suction chamber 60 and cylinder 38, groove 64 provides a spiral path that extends multiple revolutions on both the inner and outer seats of valve seat 46, whereby any minute backflow gas leakage along groove 64 when valve 48 is closed must make multiple passes or laps around each seating surface. To reduce fluid adhesion between valve 48 and seat 46, groove 64 maintains at least some minute fluid communication across valve seat 46 when valve 48 is closed.
Referring to FIG. 5, discharge valve seat 42 comprises an inner seat 42 a on center plug 52 and an outer seat 42 b on valve plate 40. The inner and outer seats define an annular discharge opening 68 between the two. Discharge opening 68 provides a gas passageway that runs past valve seat 42. Discharge valve 44 is a generally annular spring steel washer that is of a shape and size to overlie and cover discharge opening 68. Valve 44 is radially contained between a central post 70 and several peripheral posts 72 of spider 50. A back surface 74 of spider 50 limits the axial movement of discharge valve 44. Spring 54 interposed between valve 44 and surface 74 urges valve 44 to its closed position against discharge valve seat 42. When the gas pressure differential between cylinder 38 and a discharge chamber 76 overcomes the closing force of spring 54 (as a result of piston 36 extending or moving in a compression stroke 78 within cylinder 38), discharge valve 44 lifts away from valve seat 42 to an open position where valve 44 uncovers discharge opening 68.
Again, to minimize valve noise, to increase compressor efficiency, and/or to minimize the manufacturing cost of producing valve plate 40 and plug 52, the surface finish of discharge valve seat 42 is produced by machining, turning or otherwise producing a spiral groove 80 on the face of valve plate 40 and plug 52. Groove 80 preferably has an axial depth and a radial pitch that provides the face of valve plate 40 and plug 52 with a surface finish of about 10 to 250 microinches when measured along a radial path perpendicular to the groove. To avoid creating a short, direct leak path between discharge chamber 76 and cylinder 38, groove 80 provides a spiral path that extends multiple revolutions on both the inner and outer seats of valve seat 42, whereby any minute backflow gas leakage along groove 80 when valve 44 is closed must make multiple passes or laps around each seating surface. To reduce fluid adhesion between valve 44 and seat 42, groove 80 maintains at least some minute fluid communication across valve seat 42 when valve 44 is closed.
To provide additional information on the structure and function of compressor 12, U.S. Pat. Nos. 4,811,757; 6,254,354; and 6,358,026 are hereby incorporated by reference herein.
Although the invention is described with respect to a preferred embodiment, modifications thereto will be apparent to those of ordinary skill in the art. Therefore, the scope of the invention is to be determined by reference to the following claims:

Claims

1. A compressor for compressing a gas, comprising:

a compressor housing assembly defining a cylinder, a chamber, a valve seat, and a gas passageway running past the valve seat, between the chamber and the cylinder;

a reciprocating piston disposed within the cylinder; and

a valve disposed within the compressor housing assembly and being movable between a closed position and an open position, wherein the valve in the closed position obstructs the gas passageway between the chamber and the cylinder, and the valve in the open position uncovers the gas passageway, wherein the valve seat defines a spiral groove that generally faces the valve.

2. The compressor of claim 1, wherein the spiral groove extends between the chamber and the cylinder.

3. The compressor of claim 1, wherein the spiral groove is able to maintain at least some minute fluid communication between the chamber and the cylinder when the valve is in the closed position.

4. The compressor of claim 1, wherein the spiral groove provides the valve seat with a surface finish of less than 250 microinches.

5. The compressor of claim 1, wherein the spiral groove provides the valve seat with a surface finish of at least 10 microinches.

6. The compressor of claim 1, wherein the spiral groove extends a plurality of revolutions along the valve seat such that when the valve is in the closed position, the spiral groove encourages any gas that may be leaking between the chamber and the cylinder to first travel a plurality of laps along the valve seat.

7. The compressor of claim 1, wherein the valve seat includes an annular inner seat and an annular outer seat that define an annular gap therebetween, the valve has an annular shape for bridging the annular gap when the valve is in the closed position, and the spiral groove extends a first plurality of revolution along the annular inner seat and extends a second plurality of revolutions along the annular outer seat.

8. The compressor of claim 1, wherein the chamber is a discharge chamber, the valve is a discharge valve, and the gas passageway is for conveying the gas from the cylinder to the discharge chamber.

9. The compressor of claim 1, wherein the chamber is a suction chamber, the valve is a suction valve, and the gas passageway is for conveying the gas from the suction chamber to the cylinder.

10. A compressor for compressing a gas, comprising:

a compressor housing assembly defining a cylinder, a suction chamber, a discharge chamber, a suction valve seat, a discharge valve seat, a suction gas passageway between the suction chamber and the cylinder and extending past the suction valve seat, and a discharge gas passageway between the cylinder and the discharge chamber and extending past the discharge valve seat;

a reciprocating piston disposed within the cylinder;

a discharge valve disposed within the compressor housing assembly and being movable between a first closed position and a first open position, wherein the discharge valve in the first closed position obstructs the discharge gas passageway between the cylinder and the discharge chamber, and the discharge valve in the first open position uncovers the discharge gas passageway, wherein the discharge valve seat defines a first spiral groove extending between the cylinder and the discharge chamber and generally facing the discharge valve; and

a suction valve disposed within the compressor housing assembly and being movable between a second closed position and a second open position, wherein the suction valve in the second closed position obstructs the suction gas passageway between the cylinder and the suction chamber, and the suction valve in the second open position uncovers the suction gas passageway, wherein the suction valve seat defines a second spiral groove extending between the suction chamber and the cylinder and generally facing the suction valve.

11. The compressor of claim 10, wherein the first spiral groove is able to convey at least some minute backflow of gas from the discharge chamber to the cylinder when the discharge valve is in the first closed position, and the second spiral groove is able to convey at least some minute backflow of gas from the cylinder to the suction chamber when the suction valve is in the second closed position.

12. The compressor of claim 10, wherein the first spiral groove provides the discharge valve seat with a first surface finish of less than 250 microinches, and the second spiral groove provides the suction valve seat with a second surface finish of less than 250 microinches.

13. The compressor of claim 10, wherein the first spiral groove provides the discharge valve seat with a first surface finish of at least 10 microinches, and the second spiral groove provides the suction valve seat with a second surface finish of at least 10 microinches.

14. The compressor of claim 10, wherein the first spiral groove extends a first plurality of revolutions along the discharge valve seat such that when the discharge valve is in the first closed position, the first spiral groove encourages any gas that may be leaking from the discharge chamber to the cylinder to first travel a first plurality of laps along the discharge valve seat, and wherein the second spiral groove extends a second plurality of revolutions along the suction valve seat such that when the suction valve is in the second closed position, the second spiral groove encourages any gas that may be leaking from the cylinder to suction chamber to first travel a second plurality of laps along the suction valve seat.

15. A method of using a compressor to compress a gas, comprising:

driving a piston back and forth along a cylinder such that the piston alternately has a compression stroke and a return stroke, wherein the piston during the compression stroke forces the gas from within the cylinder, past a discharge valve, and into a discharge chamber, and the piston during the return stroke draws gas from within a suction chamber, past a suction valve, and into the cylinder; and

conveying at least a first minute backflow of gas along a first spiral path from the discharge chamber to the cylinder during the return stroke.

16. The method of claim 15, wherein the first spiral path is adjacent to the discharge valve.

17. The method of claim 15, further comprising conveying at least a second minute backflow of gas along a second spiral path from the cylinder to the suction chamber during the compression stroke.

18. The method of claim 17, wherein the second spiral path is adjacent to the suction valve.

19. The method of claim 17, wherein the first spiral path and the second spiral path are defined by a commonly shared valve plate.

20. The method of claim 19, wherein the first spiral path and the second spiral path are on opposite sides of the valve plate.