Pumps – With condition responsive pumped fluid control – Pressure responsive relief or bypass valve
Reexamination Certificate
1999-11-29
2001-09-11
Freay, Charles G. (Department: 3746)
Pumps
With condition responsive pumped fluid control
Pressure responsive relief or bypass valve
C418S055100, C418S055500, C418S083000
Reexamination Certificate
active
06287089
ABSTRACT:
BACKGROUND OF INVENTION
This invention relates to a scroll compressor of the sort having the non-orbiting scroll incorporating a separator plate feature, and wherein a heat shield is placed above the base of the non-orbiting scroll to reduce the amount of heat from the discharge pressure gas that reaches the non-orbiting scroll.
Modern refrigerant compressors are often mounted within a sealed container. In these compressors, the pump unit for compressing the refrigerant is positioned at one end, and a motor for driving the pump unit is positioned at another end. Often the suction pressure refrigerant is allowed to circulate over the motor, cooling the motor. In such compressors, it becomes necessary to separate the suction pressure chamber from the discharge pressure chamber. Typically, there is a plate separating the housing into a suction pressure chamber and a discharge pressure chamber.
One popular type of modern compressor is a scroll compressor. A scroll compressor includes a pair of scroll members each having a base and a generally spiral wrap extending from the base. The wraps of the two scroll members interfit to define compression chambers. One of the scroll members is driven to orbit relative to the other, and during this orbital movement, the compression chambers decrease in volume.
In traditional scroll compressors, the non-orbiting scroll does not seal against the compressor housing. Instead, a separate separator plate is positioned typically outwardly of the base of the non-orbiting scroll to separate the housing into the suction and discharge pressure chambers. Most typically, a discharge pressure chamber is formed above the separator plate, and the area below the separator plate is at suction pressure.
More recently, it has been proposed to incorporate the separator function into the base of the non-orbiting scroll. In such compressors, the base of the non-orbiting scroll is sealed to the housing. Thus, there is the discharge pressure chamber on one side of the base of the on-orbiting scroll.
In refrigerant compressors, compressed refrigerant often reaches relatively high temperatures. With the above discussed recent scroll compressor improvements, this hot gas communicates with the rear of the base of the non-orbiting scroll. The scroll base may thus reach undesirably high temperatures thus transferring a significant amount of heat to the suction side of the compressor.
SUMMARY OF THE INVENTION
In a disclosed embodiment of this invention, a scroll compressor has an orbiting scroll member and a non-orbiting scroll member. The non-orbiting scroll is also utilized to separate a housing containing both scroll members into suction and discharge pressure chambers. Preferably, the non-orbiting scroll has an outer peripheral surface which is sealed to an inner peripheral surface of the housing to seal the housing and define the suction and discharge pressure chambers. Other ways of sealing the non-orbiting scroll to the housing may be used. A thin heat shield is provided outwardly of the base of the non-orbiting scroll to minimize heat from the discharge pressure chamber reaching the base of the non-orbiting scroll.
In a preferred embodiment, the heat shield may be a thin metal shield such as steel, or may be formed of a plastic. It is preferred that the heat shield be positioned between the discharge pressure chamber and the seal point between the non-orbiting scroll and the housing.
In another feature, the heat shield is provided with leakage paths such that some discharge pressure refrigerant can leak beyond the heat shield and into chambers between the heat shield and the non-orbiting scroll. The discharge pressure refrigerant in these chambers will reduce any likelihood of vibration or noise due to minute pressure differences across the heat shield.
In one embodiment, a pressure relief valve extends through the base of the non-orbiting scroll, and extends through the heat shield. Preferably, the heat shield opening which receives the valve is larger than the outer periphery of the valve such that there is clearance between the valve and the heat shield opening. This allows assembly of the parts and provides additional passages for pressure-balancing gas to move into the chambers.
Also, the shield could have a through hole. This is the preferred embodiment with the relief valve mounted on the suction side.
In another embodiment, the heat shield surrounds a boss in the base of the non-orbiting scroll which receives the check valve. There is either a clearance, such as the first embodiment, or the boss is formed within an irregular outer surface such that leakage paths are maintained.
The non-orbiting scroll is preferably provided with an outer surface on the base facing the discharge pressure chamber which is convoluted to provide structural strength. In a preferred embodiment, there is a radially outer center rib with indentions both axially below and axially above the central rib. In the present invention, these indentions provide the chambers mentioned above which receive the discharge pressure gas. Further, other ribs extend radially outwardly and are curved to support the inner surface of the heat shield. The indentions extend between these radially extending ribs.
REFERENCES:
patent: 5487654 (1996-01-01), Wallis et al.
patent: 5649816 (1997-07-01), Wallis et al.
patent: 5674062 (1997-10-01), Weatherston
patent: 57-206786 (1982-12-01), None
patent: 8-210273 (1996-08-01), None
Dewar Todd
Fields Gene Michael
Hill Joe T.
Milliff Tracy
Williams John R.
Carlson & Gaskey & Olds
Freay Charles G.
Gray Michael K.
Scroll Technologies
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