Dual-Motion Shutoff Valve Sequencing for Low-Torque Sealing
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Solution Overview
Problem
Ball and butterfly valves experience increased friction and wear due to the constant contact between the metal ball or butterfly disk and the gasket during operation, leading to higher operational torque and potential leakage, which reduces the lifespan of the valve assembly.
Innovation Solution
A dual motion shutoff valve assembly with a sequencing drive mechanism and an eccentric shaft that linearly retracts the valve disk from the gasket surface before rotating, reducing friction and wear by using interlocking rollers and guide pins to manage the valve's position between open and closed states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve disk remains in constant contact with the gasket during operation, then the sealing reliability is improved, but the friction and wear between the metal ball or butterfly disk and the gasket increases
Solution Approach 1:
The sequencing drive mechanism performs a preliminary linear retraction action that moves the valve disk away from the gasket surface before the rotational closing action begins. This preliminary retraction prevents the valve disk from sliding across the gasket during rotation, thereby reducing friction and wear while maintaining sealing reliability when the valve is closed.
Solution Approach 2:
The valve disk movement is segmented into two distinct phases: a linear retraction phase where the valve disk moves perpendicular to the gasket surface, and a rotational phase where the valve disk rotates into the closed position. This segmentation eliminates the harmful sliding motion that occurs in traditional single-motion valves, reducing wear on both the valve disk and gasket.
2Duration of action of moving object
If the valve disk is retracted linearly from the gasket before rotation, then friction and wear are reduced, but the device complexity increases due to the sequencing drive mechanism
Solution Approach 1:
The sequencing drive mechanism combines the linear retraction and rotational movements into a single integrated actuator system. The mechanism uses interconnected components including a drive shaft, cam followers, and linkages that automatically sequence the retraction and rotation actions, eliminating the need for separate actuators for each motion phase.
Solution Approach 2:
The sequencing drive mechanism employs dynamic elements such as cams and followers that automatically adjust the valve disk position based on the actuation sequence. The cam profile is designed to provide the precise retraction distance and timing, while the follower ensures smooth transition between linear and rotational motions, adapting to varying operating conditions.
3Speed
If the valve disk rotates directly from closed to open position without retraction, then the operational speed is improved, but the operational torque increases due to friction
Solution Approach 1:
The sequencing drive mechanism performs a preliminary linear retraction action that moves the valve disk away from the gasket surface before the rotational opening action begins. This preliminary retraction eliminates friction during the majority of the rotation travel, significantly reducing the torque required to operate the valve while maintaining high operational speed.
Data Source
AI summary
Technologies are described for dual motion shutoff valve assemblies. In various examples, valve assemblies include a sequencing drive mechanism and an eccentric shaft mechanism operable to linearly retract the valve disk from a gasket surface to effectively reduce scratching and friction of the gasket surface during valve opening and closing operations. In some examples, the sequencing drive may include two interlocking concentric driver rings, a retaining housing, and roller lock pins. Three guided pins of the sequencing drive may be configured to prevent the valve from rotating, while also causing the valve to retract linearly from the gasket surface via the eccentric shaft. Following retraction, an inner driver of the sequencing drive may allow the roller lock pins to move and lock the outer driver, which in turn may lock the valve disk to the shaft and rotate along with the shaft, which may be a single or dual shaft.