Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2000-02-24
2001-04-17
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055500, C418S057000
Reexamination Certificate
active
06217302
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a scroll compressor having a floating seal which has a protection device which is actuated upon reverse rotation.
Scroll compressors are becoming increasingly popular for refrigerant compression applications. In a scroll compressor a first scroll member has a base and a generally spiral wrap extending from the base.
A second scroll member also has a base and a generally spiral wrap extending from its base. The wraps of the first and second scroll member interfit to define compression chambers. The second scroll member is caused to orbit relative to the first scroll member, and as the wraps orbit relative to each other, a refrigerant to be compressed is entrapped and moved toward a discharge port.
As the refrigerant is compressed, a force is created tending to separate the first and second scroll member. One technique utilized to address this separating force is a back pressure chamber. A back pressure chamber is defined by tapping a compressed fluid to a chamber defined by seals behind one of the first or second scroll members. The fluid in the chamber creates a force in opposition to the separating force. In one known type of scroll compressor, the first scroll member, known as the non-orbiting scroll, is axially moveable relative to the second scroll member. A seal is placed in the base of the non-orbiting scroll and defines the back pressure chamber. This seal also separates an inlet zone from a discharge pressure zone.
During normal operation the seal is biased into contact with another component in the scroll compressor. Typically, the seal is biased against a separator plate which defines a discharge pressure chamber above the non-orbiting scroll. The seal is moveable away from the separator plate wall to allow the discharge and suction pressure zones to communicate.
Scroll compressors are sometimes prone to operation in a reverse direction. When the scroll compressor is operated in a reverse direction, the refrigerant is drawn through the discharge port, into the compression chambers, and then outwardly through the suction port. Operation in reverse rotation is undesirable, and potentially detrimental to the scroll compressor.
In the prior art mentioned above, operation in the reverse rotation will typically draw the seal away from the separator plate wall, allowing the discharge and suction pressure zones to communicate. This is true since the fluid which is tapped to the back pressure chamber will be at a very low pressure during reverse rotation. The seal will thus be drawn away from the plate, allowing communication between the discharge and suction pressure zone. This is somewhat undesirable, as oil is allowed to enter the discharge port from the suction pressure zone. The oil is then pumped through the scrolls and out of the compressor through a suction tube. This can lead to a loss of oil within the scroll compressor.
It would be desirable to have a scroll compressor seal which is structured to prevent the communication of the suction and discharge pressure zones during reverse rotation.
SUMMARY OF THE INVENTION
In the disclosed embodiment of this invention, a seal is mounted in the base of the non-orbiting scroll. The seal is biased into contact with the separator plate to define a back pressure chamber. An intermediate pressure fluid is tapped to the back pressure chamber to create a back pressure force resisting a separating force. During normal operation, the seal is maintained in contact with the separator plate. At this position the seal also separates a discharge pressure zone radially inwardly of the seal from a suction pressure zone, which is radially outward of the seal.
Upon reverse rotation, the pressure at the intermediate pressure zone will drop dramatically. This low pressure will draw the seal downwardly away from the separator plate. In the prior art, when this occurred, the discharge pressure zone communicates with the suction pressure zone. Oil in the suction pressure zone enters the discharge pressure zone, and is then pumped out the compressor through a suction tube. As mentioned above, this is undesirable.
The present invention addresses this concern by providing a check valve working with the seal. The check valve prevents flow from the back pressure chamber through the seal in a direction towards the separator plate. However, during reverse rotation, the relatively high pressure in the suction zone will pass into the tap, moving through the check valve and into the back pressure chamber. In this way, the relatively high pressure fluid in the suction zone will move into the back pressure chamber, preventing movement of the seal downwardly away from the separator plate. The flow of a large amount of oil from the suction pressure zone into the discharge pressure zone is prevented. In embodiments, the check valve could be in the seal or in the non-orbiting scroll.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
REFERENCES:
patent: Re. 35216 (1996-04-01), Anderson et al.
patent: 5102316 (1992-04-01), Caillat et al.
patent: 5447418 (1995-09-01), Takeda et al.
patent: 5462419 (1995-10-01), Hill et al.
patent: 5469716 (1995-11-01), Bass et al.
patent: 5489198 (1996-02-01), Comparin et al.
patent: 5580229 (1996-12-01), Beck et al.
patent: 5611674 (1997-03-01), Bass et al.
patent: 5649816 (1997-07-01), Wallis et al.
patent: 6017205 (2000-01-01), Weatherston et al.
patent: 6146119 (2000-11-01), Bush et al.
patent: 5-157063 (1993-06-01), None
patent: 6-241177 (1994-08-01), None
Barito Thomas
Bush James W.
Hahn Greg
Hill Joe T.
Hugenroth Jason
Carlson & Gaskey & Olds
Denion Thomas
Scroll Technologies
Trieu Theresa
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