Offset Butterfly Valve Alignment for Leak-Tight Sealing
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Solution Overview
Problem
Existing butterfly valves for gas lines, particularly in fuel cell systems, face challenges in achieving a perfect seal with low actuation forces while minimizing wear and manufacturing complexity, especially when used in environments requiring high leak-tightness, such as hydrogen fuel cells.
Innovation Solution
A valve arrangement with a pivot axis offset from the valve flap plane, allowing for alignment and fixation of the valve flap relative to the valve seat in multiple directions using an alignment mechanism, which includes a screw fastening or adhesive/welding, enabling precise adjustment and fixation without increasing actuation forces or wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a butterfly valve with centrally arranged pivot axis is used, then the valve can be actuated with relatively low actuating forces, but relatively high manufacturing outlay is required to attain an optimum seal and low wear
Solution Approach 1:
The patent applies asymmetry by offsetting the pivot axis from the center of the valve disk. The pivot axis is positioned at a distance from the center in both radial and axial directions, creating an asymmetric configuration that simplifies the sealing surface geometry to a basic conical shape while maintaining effective sealing performance. This asymmetric arrangement reduces manufacturing complexity compared to centralized pivot designs.
Solution Approach 2:
The patent introduces a third dimension (axial offset) in addition to the radial offset of the pivot axis. The pivot axis is offset from the valve disk center both radially (in the plane of the disk) and axially (perpendicular to the disk plane). This dual-dimensional offset creates a doubly offset butterfly valve configuration that simplifies sealing surface requirements while maintaining actuation efficiency.
2Ease of manufacture
If the pivot axis is offset in two directions to simplify sealing surfaces, then manufacturing is easier, but the alignment of the valve flap relative to the valve seat becomes sensitive to production tolerances
Solution Approach 1:
The patent implements preliminary action by providing adjustment mechanisms that allow the valve flap to be aligned with the valve seat before final fixation. The valve flap can be adjusted in the angular direction around the pivot axis to achieve optimal alignment, and this adjusted position is then fixed. This preliminary adjustment compensates for production tolerances and ensures proper sealing without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The patent introduces dynamic adjustability to the otherwise fixed pivot axis configuration. The pivot axis position can be adjusted within a certain range to accommodate production tolerances and achieve optimal alignment between the valve flap and valve seat. This dynamic adjustment capability transforms a static, tolerance-sensitive design into a flexible, tolerance-compensating design.
3Reliability
If a conical sealing surface is used to improve seal quality, then sealing performance is enhanced, but wear in the sealing region increases
Solution Approach 1:
The patent modifies the geometric parameters of the sealing surface by using a basic conical shape with specific angle and radius of curvature characteristics. The conical surface is designed with optimized parameters that distribute contact pressure more favorably, reducing stress concentration and minimizing wear while maintaining effective sealing. The specific cone angle and surface finish parameters are selected to balance sealing performance with wear resistance.
Data Source
AI summary
A valve arrangement, having a housing with a fluid line and a valve arranged in the fluid line which has a valve seat, a valve flap, and a valve opening, the valve flap being pivotable about a pivot axis between a closed position, in which the valve flap lies against the valve seat and closes the valve in fluid-tight fashion, and an open position, in which the valve flap opens up the valve opening. The valve flap, in the closed position, defining an X-Y plane of a coordinate system and the pivot axis being arranged with a spacing to the X-Y plane and defining the Y direction of the coordinate system. An alignment mechanism aligns the arrangement in which the valve flap is situated relative to the valve seat in the closed position to be is alignable and fixable at least in the X direction.