Ball Valve Seat Decoupling to Reduce Wear and Leakage
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Solution Overview
Problem
Conventional ball valves experience excessive wear and deterioration due to continual rubbing between the seats and the ball, which degrades performance and fails to meet strict leakage standards in applications like industrial gas turbine fuel metering.
Innovation Solution
A ball valve design featuring a metering seat that maintains contact with the ball for flow control and a sealing seat lifted off the ball via cam followers, preventing rubbing and using a weaker biasing force for the metering seat to reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing seat remains in contact with the ball during operation, then the valve maintains reliable sealing capability, but the continual rubbing causes excessive wear and reduces valve endurance
Solution Approach 1:
The sealing seat is designed to dynamically change its contact state with the ball based on valve position. During valve operation, the sealing seat is lifted off the ball surface to eliminate continual rubbing. The sealing capability is maintained through the metering seat's contact with the ball, which provides the necessary sealing function without the excessive wear caused by the sealing seat's continual contact.
Solution Approach 2:
The sealing function is segmented between two separate seats: the sealing seat and the metering seat. The sealing seat is responsible for preventing leakage in the closed position, while the metering seat maintains contact with the ball during operation to prevent leakage around the ball. This segmentation allows the sealing seat to be lifted off during operation, reducing wear, while the metering seat maintains the necessary sealing function.
2Duration of action of moving object
If the sealing seat is lifted off the ball using cam followers, then wear is reduced and endurance is enhanced, but the device complexity increases
Solution Approach 1:
Cam followers are introduced as intermediary elements to lift the sealing seat off the ball surface during valve operation. These followers convert the rotational motion of the ball into linear motion of the sealing seat, eliminating direct contact and rubbing between the sealing seat and ball. The metering seat serves as another intermediary that maintains contact with the ball to provide sealing function without causing excessive wear.
3Duration of action of moving object
If materials and coatings are used to reduce wear, then endurance is slightly improved, but the wear from continual rubbing persists and does not meet strict leakage standards
Solution Approach 1:
The harmful rubbing action is extracted from the system by lifting the sealing seat off the ball surface during operation. This eliminates the continual contact that causes wear, addressing the root cause rather than merely treating the symptoms with materials and coatings. The sealing function is maintained through the metering seat's contact with the ball, which provides necessary sealing without the excessive wear caused by the sealing seat's continual contact.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the endurance and life of the valve by preventing contact between the sealing seat and ball in the open position, maintaining flow accuracy, and reducing wear, suitable for applications with stringent leakage requirements.
Implementation Method 1
a follower coupled to the sealing seat, wherein when the ball is in the open rotational range, the follower is engaged with the cam surface, thereby lifting the sealing seat off the ball
Data Source
AI summary
An example valve includes: a ball rotatable by a shaft, wherein the ball has a cam surface; a metering seat that contacts the ball; a sealing seat that contacts the ball when the ball is in a closed position; and a follower coupled to the sealing seat, wherein when the ball is in an open rotational range that allows fluid flow from a first port to a second port, the follower is engaged with the cam surface, thereby lifting the sealing seat off the ball, while the metering seat remains in contact with the ball.