Butterfly Valve Free-Form Sealing Surface for Lower Actuation Torque
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Solution Overview
Problem
Existing butterfly valve designs experience high friction between the sealing surface and the seal, leading to increased torque requirements when actuating the shut-off flap, which is not minimized in previous asymmetric designs.
Innovation Solution
The sealing surface is designed as an arbitrarily shaped, free-form surface, represented by curves or rays connecting cross-sections, allowing for uniform seal movement away from the sealing surface, reducing friction and torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sealing surface is designed as a conventional symmetric or asymmetric shape (cone/pyramid), then the valve structure is simple and manufacturing is easier, but the friction between sealing surface and seal is high leading to increased torque requirements
Solution Approach 1:
The patent applies asymmetry by designing the sealing surface with a free-form geometry that is intentionally asymmetric relative to the valve centerline. This asymmetric configuration allows the seal to move uniformly away from the sealing surface during actuation, reducing friction and torque requirements while maintaining effective sealing when closed.
Solution Approach 2:
The patent changes the geometric parameters of the sealing surface from conventional symmetric shapes (cones/pyramids) to a free-form asymmetric shape defined by specific mathematical equations. This parameter transformation optimizes the seal's movement characteristics and friction properties while maintaining manufacturability through CNC machining.
2Ease of operation
If the sealing surface is designed as an arbitrarily shaped free-form surface, then friction and torque are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent replaces traditional mechanical manufacturing methods with CNC computer numerical control machining. This substitution enables the precise fabrication of complex free-form asymmetric surfaces that would be difficult or impossible to manufacture using conventional mechanical methods, while maintaining production efficiency and accuracy.
3Reliability
If the seal moves non-uniformly across the sealing surface, then sealing effectiveness is maintained, but friction increases and torque requirements rise
Solution Approach 1:
The patent applies local quality by designing the sealing surface with varying local geometries along its length. The free-form shape creates different local angles and curvatures that guide the seal's movement, ensuring uniform separation across the entire sealing circumference while maintaining effective contact and sealing when the valve is in the closed position.
Data Source
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AI summary
2. A butterfly valve for controllable medium flow is specified. This butterfly valve is characterized by a design with a total of six asymmetries, in contrast to prior art designs which have a maximum of three or four asymmetries.