Double Eccentric Valve Sticking Prevention
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Solution Overview
Problem
The existing butterfly valve technology fails to reliably prevent sticking between the valve seat and the valve element, especially when deposits form or freeze, leading to unstable operations and potential biting issues during valve closure.
Innovation Solution
A double eccentric valve design is implemented, featuring a valve seat and element with eccentrically positioned components, a rotary shaft, a drive mechanism, a bearing, and a return spring that generates a separating force to maintain a gap between the valve seat and element during non-operation, preventing sticking and allowing precise control of the valve opening degree for accurate flow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the gap between the valve seat and the valve element is set small to reduce leakage, then the leakage amount is reduced, but the valve seat and the valve element may bite each other causing sticking
Solution Approach 1:
The patent employs double eccentric positioning: the rotary shaft is positioned eccentrically from the valve hole center, and the sealing surface is positioned eccentrically from the rotary shaft center. This asymmetric configuration creates a variable gap that remains small during operation to reduce leakage but maintains separation when the valve is closed to prevent sticking.
Solution Approach 2:
The return spring is pre-loaded to generate a separating-direction urging force that acts on the rotary shaft during non-operation. This preliminary action maintains a slight gap between the valve seat and valve element before any operational stress is applied, preventing deposits or foreign matters from causing sticking.
2Productivity
If the valve stops at a midpoint within the rotatable range, then the valve can control flow, but the valve seat and the valve element may stick due to deposits during non-energization
Solution Approach 1:
The return spring provides a counteracting separating force that balances the closing force of the valve element against the valve seat. During non-energization, this counter force maintains a slight gap that prevents sticking, while during operation the drive mechanism overcomes this spring force to achieve the desired valve positioning for flow control.
Solution Approach 2:
The valve system transitions from a static closed position to a dynamic controlled position. The return spring dynamically adjusts the valve element position during non-operation to prevent sticking, while the drive mechanism dynamically positions the valve at various opening degrees during operation for precise flow control.
3Ease of operation
If foreign matters are caught between the valve seat and the valve element during valve closing, then the valve closes, but the foreign matters do not drop off causing biting
Solution Approach 1:
The return spring applies a separating-direction urging force during non-operation that creates a slight gap between the valve seat and valve element. This preliminary separation action prevents foreign matters from being trapped and causing biting, while still allowing complete valve closure when the drive mechanism overcomes the spring force.
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 effectively prevents sticking and ensures stable operation by maintaining a gap between the valve components, even during engine stop or freezing conditions, and enhances flow control accuracy by allowing a small initial open area, reducing the risk of foreign matter-induced biting and improving valve element positioning for precise flow regulation.
Implementation Method 1
a return spring configured to generate a return spring force to rotate the rotary shaft in a valve closing direction
Implementation Method 2
the double eccentric valve generates a separating-direction urging force to cause the rotary shaft to incline about the bearing serving as a fulcrum and urge the valve element in a direction away from the valve seat
Data Source
AI summary
A double eccentric valve includes: a drive mechanism which produces drive force for rotating a rotary shaft in a direction to open the valve; a drive force receiving unit provided integrally with the rotary shaft to receive the drive force; a bearing located between a valve element and the drive force receiving unit along the center axis of the rotary shaft to support the rotary shaft; and a return spring which produces return spring force for rotating the rotary shaft in a valve closing direction. The double eccentric valve is configured to generate a separating-direction biasing force which inclines the rotary shaft with the bearing at a fulcrum to bias the valve assembly away from a valve seat, the force being caused by the return spring force when the drive mechanism is not operated and acting in a direction perpendicular to the center axis of the bearing.