Contoured Check Valve Disc to Prevent Scroll Compressor Stiction
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Solution Overview
Problem
In scroll compressors, the oil mist environment creates 'stiction' between the check valve disc and the stop plate, preventing normal release and allowing high-pressure refrigerant to reverse flow, which can cause the scroll compressor to run in reverse when shut off.
Innovation Solution
A check valve design with a relieved region along the contact interface between the valve disc and the retainer, minimizing surface contact to prevent static cohesion sticking forces, allowing the valve disc to dish under pressure and reduce stiction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat-to-flat contact interface is used between the check valve disc and stop plate, then sealing action is achieved, but static cohesion sticking force (stiction) prevents normal release of the valve disc
Solution Approach 1:
The valve disc is modified to include a relieved region that creates a curved or contoured contact surface instead of a flat-to-flat interface. This curvature reduces the contact area between the valve disc and stop plate, minimizing the surface tension and static cohesion forces that cause stiction, while still maintaining adequate sealing when the valve is closed
2Reliability
If the check valve disc sticks to the stop plate, then sealing is maintained, but high-pressure refrigerant can reverse flow through peripheral ports
Solution Approach 1:
The contoured contact surface on the valve disc reduces stiction by minimizing contact area, allowing the valve disc to release properly from the stop plate. This prevents the condition where stuck valves allow high-pressure refrigerant to reverse flow through peripheral ports, while the valve seat geometry maintains reliable sealing when closed
3Stability of the object's composition
If complete surface contact is provided between valve disc and retainer, then structural stability is achieved, but static cohesion sticking force increases
Solution Approach 1:
The relieved region creates a contoured contact surface that reduces the contact area between the valve disc and retainer. This minimizes the static cohesion sticking force while the remaining contact area and structural design maintain adequate structural stability for valve operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents static cohesion sticking forces, ensuring proper valve operation and preventing reverse flow of refrigerant, thus maintaining the compressor's functionality and efficiency.
Implementation Method 1
the oil mist environment allows sealing action between the flat geometry of these two structures such that the normal tendency of the check valve disc to release from this flat-to-flat contact is prevented by suction created when there is an attempt to move the check valve disc away from the corresponding stop plate
Data Source
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AI summary
A check valve is provided which may be integrated into a scroll compressor that prevents static cohesion sticking forces between a valve disc member and a retainer member of the check valve housing. Such static cohesion sticking forces may be particularly generated due to oil mist generation in such scroll compressors which create a thin lubricant film between the valve disc and the stop plate of the check valve housing, creating suction type static cohesion when dislodgment of the valve disc away from the stop plate is attempted. A relief region is created between the retainer and the valve disc creating a minimal contact surface area that greatly reduces and/or eliminates such static cohesion sticking forces. For example, the valve disc may be dished to have a concave surface that faces the retainer element provided by the stop plate.