Ball Valve Seal Geometry for Low-Wear Closing Contact
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Solution Overview
Problem
Ball valves experience seal wear due to contact with the housing and seat during actuation, leading to potential leakage and downtime, especially in critical applications, as existing solutions either introduce complex retraction mechanisms or require oversized valve housings.
Innovation Solution
The design features a ball valve with a seal and seat arrangement where the seal is asymmetric in geometry, with the leading edge oriented at a steeper angle than the trailing edge, minimizing contact to only the last few degrees of travel, eliminating the need for a separate retraction mechanism and maintaining a compact valve housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal contacts the housing and seat during actuation, then sealing is achieved, but seal wear increases
Solution Approach 1:
The seal is designed to dynamically change its position relative to the ball during actuation. The seal extends during the majority of the ball's rotation to minimize contact and wear, then retracts only during the final few degrees of travel to achieve sealing contact with the seat, thus resolving the contradiction between maintaining sealing and reducing seal wear.
Solution Approach 2:
The seal retraction mechanism is activated in advance during the final degrees of ball rotation before full closure is achieved. This preliminary retraction ensures that the seal is already in the correct position to make contact with the seat at the precise moment needed for sealing, preventing premature contact and reducing overall wear during actuation.
2Duration of action of moving object
If a seal retraction mechanism is added, then seal wear is reduced, but device complexity increases
Solution Approach 1:
The seal retraction mechanism is merged with the seal assembly itself, integrating the retraction function into the existing seal structure rather than adding a separate, independent mechanism. This integration reduces overall device complexity while still achieving the goal of reduced seal wear through controlled retraction during actuation.
Solution Approach 2:
The seal assembly is designed to perform its own retraction function through its inherent mechanical geometry and interaction with the ball during rotation. The seal's asymmetric profile and engagement with the ball create automatic retraction during actuation without requiring external actuators or complex control systems, thus reducing device complexity while extending seal service life.
3Duration of action of moving object
If the valve housing is oversized to accommodate seal retraction, then seal wear is reduced, but valve size increases
Solution Approach 1:
The seal dynamically adjusts its position within the existing valve housing dimensions. By extending during most of the actuation cycle and retracting only during the final degrees of rotation, the seal achieves wear reduction without requiring additional space in the housing, thus resolving the contradiction between extending seal life and maintaining compact valve size.
Solution Approach 2:
The seal's operational parameters are changed by varying its extension/retraction state during different phases of actuation. This temporal parameter change allows the seal to minimize wear during the majority of rotation while still achieving proper sealing contact, all within the constraints of the original valve housing volume without requiring oversizing.
Data Source
AI summary
A ball valve is disclosed herein. The ball valve can include a non-planar seal disposed upon a rotating ball, the ball and seal contained within a housing, wherein the seal includes a first section and a second section, the first section oriented at a different angle than the second section. The ball valve can further include a mating surface disposed within the housing adjacent to the ball, the mating surface arranged to fully contact the seal when the ball valve is in a closed position, the mating surface including a first section and a second section, the first section oriented at a different angle than the second section. The seal and mating surface can be oriented so that the first section of the seal does not contact the second section of the mating surface when the ball is rotated between a closed position and an open position.