Triple-Offset Valve Sealing Surface to Minimize Wear
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Solution Overview
Problem
Existing butterfly valves with triple offset designs face challenges in maintaining tight sealing and minimizing wear over their life cycle, as the sealing surfaces contact only at the final point of closure, leading to potential leakage and increased friction.
Innovation Solution
The adoption of a triple eccentric non-conical shape for the sealing surfaces, defined by super-poly-conically developable surfaces with offset focal points, which provides a more even distribution of contact pressure and reduces wear by ensuring the sealing surfaces are not conical, allowing for a non-conical, double-curved sealing surface that maintains integrity throughout the closure member's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a triple offset conical sealing surface design is used, then the valve achieves tight sealing at closure, but the sealing surfaces experience increased wear and friction during operation
Solution Approach 1:
The patent applies a non-conical, double-curved sealing surface geometry that eliminates the conical shape. The sealing surface is formed with a radius of curvature that varies along the flow direction, creating a more complex curved profile. This curvature distribution ensures even contact pressure across the sealing interface while reducing stress concentration, thereby minimizing wear and extending service life while maintaining sealing integrity.
2Ease of operation
If the rotation axis is offset from the centerline (triple eccentric design), then the valve achieves over-travel-free stroking, but the sealing surfaces experience premature contact and increased operational stress
Solution Approach 1:
The patent implements local quality by varying the radius of curvature along the sealing surface in the flow direction. This creates zones of different contact pressure distribution, with the curvature optimized at specific locations to ensure even stress distribution. The local curvature adjustment compensates for the offset rotation axis effects, reducing premature contact and operational stress while maintaining ease of operation.
3Ease of manufacture
If a conical sealing surface is used, then the valve structure is simpler to manufacture, but the sealing performance deteriorates due to uneven contact pressure distribution
Solution Approach 1:
The patent replaces the simple conical surface with a non-conical, double-curved surface characterized by a radius of curvature that varies along the flow direction. This more complex geometry can be manufactured using modern machining or forming techniques, and it provides superior sealing performance by ensuring even contact pressure distribution across the sealing interface, eliminating the uneven pressure problems associated with conical surfaces.
Data Source
AI summary
A valve including: a flow channel and a closure member. A first sealing surface is provided along walls of the flow channel and a second sealing surface is provided along outer edges of a sealing section of the closure member. A rotation axis is offset from the sealing section by a first predetermined distance and from a centerline of the closure member by a second predetermined distance. To ensure smooth operation of the closure member at least one of the first and second sealing surfaces has a non-conical shape that is at least in one area asymmetric with respect to the center axis of the closure member.