Floating Butterfly Disc Structure for Leak-Resistant Valve Sealing
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Solution Overview
Problem
Prior butterfly valves are susceptible to leaking due to seal wear and deflection under torsional and pressure loads, leading to improper sealing and leakage, as the disc is held rigidly within the valve housing.
Innovation Solution
A triple-offset butterfly valve design featuring a butterfly disc with a raised part, female spline, and re-enforcement, along with a stem and actuator system that allows the disc to self-position and engage with the valve seat for improved sealing, and a ring seal that extends beyond the disc's periphery to close the aperture, enhancing stiffness and reducing backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the disc is held rigidly within the valve housing, then the structural stability is improved, but the sealing reliability deteriorates due to seal wear and deflection under loads
Solution Approach 1:
The butterfly disc is designed to float along the stem rather than being rigidly fixed, allowing it to dynamically adjust its position in response to pressure differentials and torsional forces. This dynamic positioning capability enables the disc to maintain optimal sealing contact with the valve seat while accommodating operational loads and seal wear, thereby resolving the contradiction between structural stability and sealing reliability
2Manufacturing precision
If the disc is rigidly held in position, then the manufacturing precision is improved, but the sealing performance deteriorates due to deflection under torsional and pressure loads
Solution Approach 1:
The patent changes the positioning parameter from fixed to floating, allowing the disc to move axially along the stem. This parameter change enables the disc to compensate for deflections caused by torsional and pressure loads, maintaining sealing performance while simplifying manufacturing requirements compared to rigid positioning systems
3Reliability
If the seal is designed to extend beyond the disc periphery, then the sealing effectiveness is improved, but the device complexity increases
Solution Approach 1:
The sealing function is segmented into two independent components: the ring seal extending beyond the disc periphery for primary sealing, and the disc seal at the disc edge for secondary sealing. This segmentation allows each seal to be optimized for its specific function without increasing overall complexity, as the seals operate independently and can be manufactured as separate elements
Data Source
AI summary
An offset butterfly valve comprising a butterfly disc which receives a splined valve stem is disclosed. The butterfly disc is positioned for sealing an annulus formed in the valve housing when the valve stem is rotated from an open position to closed position. Provision of the spline towards the center of the valve stem and the butterfly disc allows the butterfly disc to move along the valve stem. In a particular embodiment a valve seal is secured to the butterfly disc using a securing disc which is threaded into a threaded cylinder concentric with the butterfly disc.