Flow Path Switching Valve Bypass Mechanism Hysteresis
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Solution Overview
Problem
Flow path switching valves exhibit hysteresis due to the elastic deformation of the membrane, leading to pressure loss and increased response time in pressure control circuits, which is affected by material tolerances and wear over time.
Innovation Solution
The inner peripheral wall of the valve chamber is designed with a bypass mechanism that cancels the sealing contact of the diaphragm in part of its circumference when the valve piston reaches the first end position, eliminating hysteresis without affecting the valve's basic function and increasing the flow cross-section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the membrane maintains sealing contact with the peripheral wall to enable valve function, then the valve can switch flow paths, but hysteresis occurs due to pressure loss when air flows past the membrane
Solution Approach 1:
The sealing contact between the membrane and peripheral wall is segmented into two distinct zones: a first section where sealing contact is maintained for proper valve function, and a second section where sealing contact is canceled to eliminate hysteresis. This segmentation allows the valve to maintain reliability while reducing pressure loss.
Solution Approach 2:
Different sections of the membrane-peripheral wall interface have different functional qualities: the first section provides sealing contact for valve operation, while the second section provides a bypass path with no sealing contact to eliminate hysteresis. This local differentiation resolves the contradiction between maintaining valve function and eliminating pressure loss.
2Ease of operation
If the membrane elasticity is maintained for valve operation, then the valve can respond to pressure changes, but the response time increases due to hysteresis
Solution Approach 1:
The membrane sealing contact is segmented into a first section for valve operation and a second section canceled to eliminate hysteresis. This allows the valve to maintain its pressure-responsive operation while removing the time-delaying hysteresis effect.
Solution Approach 2:
The harmful hysteresis effect is extracted and removed by canceling the sealing contact in the second section of the membrane-peripheral wall interface, while preserving the necessary sealing contact in the first section for valve operation. This extraction eliminates the time loss without compromising operational ease.
3Manufacturing precision
If the membrane sealing contact is maintained for pressure control, then the valve can regulate flow, but manufacturing tolerances and wear affect performance consistency
Solution Approach 1:
The sealing contact is segmented into a first section that maintains manufacturing precision requirements and a second section that is canceled to eliminate sensitivity to tolerances and wear. This segmentation improves reliability by removing the performance-critical sealing contact from the hysteresis-prone second section.
Solution Approach 2:
The source of performance inconsistency (the sealing contact in the second section) is extracted and removed. By canceling this sealing contact, the valve becomes less sensitive to manufacturing tolerances and wear, thereby improving performance consistency while maintaining necessary pressure control in the first section.
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
This design suppresses hysteresis, allowing for quicker and more precise control of the valve, reducing the impact of membrane wear and tolerances on the valve's performance and enhancing pressure control accuracy.
Implementation Method 1
the elastic deformation of the membrane
Implementation Method 2
the hysteresis described is eliminated
Data Source
Figure 1~2
Figure 3~5
Figure 6~9d
AI summary
The flow path switching valve described here has a valve chamber (13) with three openings (21, 22, 23) and a valve piston (14) disposed in the valve chamber. The valve piston (14) has an elastic diaphragm (15) which cooperates sealingly at the circumference thereof with an inner circumferential wall (16) of the valve chamber (13). The valve piston (14) is movable between two end positions: in a first end position, it opens a flow path between the first opening (21) and the second opening (22) and blocks the third opening (23), and in the second end position, it blocks the first opening (21) and opens a flow path between the second opening (22) and the third opening (23). The valve chamber wall (16) is shaped such that the sealing contact between the diaphragm (15) and the inner wall is undone, at least around some of the circumference, in the last phase of the diaphragm movement into the first end position.