Contoured Ball Valve Seat Assembly for Low-Wear Sealing
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Solution Overview
Problem
Traditional ball valves face challenges in maintaining consistent sealing and preventing wear due to uneven contact stress and potential galling between seats and counterseats, especially under high-pressure conditions, which can lead to reduced valve cycle life and increased maintenance.
Innovation Solution
The design incorporates toroidal convex and spherical concave sealing surfaces for the seats and counterseats, allowing for differential piston effects under fluid pressure to enhance sealing pressure and reduce contact area, along with mechanical retraction mechanisms like retaining caps and pressure-relief ports to manage stress and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional seats and counterseats are used in ball valves, then sealing is achieved, but uneven contact stress and galling occur leading to wear and reduced valve cycle life
Solution Approach 1:
The patent applies spherical curvature to the sealing surfaces of both the seat and counterseat, creating spherical sealing surfaces that distribute contact stress uniformly across the interface. This spherical geometry eliminates the uneven contact stress and galling problems associated with traditional flat or conical sealing surfaces, thereby improving sealing consistency while extending valve cycle life through reduced wear.
Solution Approach 2:
The patent changes the geometric parameters of the sealing surfaces from traditional flat or conical shapes to spherical surfaces with specific radii of curvature. This parameter change transforms the contact stress distribution from uneven to uniform, preventing galling and wear while maintaining effective sealing throughout the valve's operational life.
2Reliability
If seats and counterseats are allowed to move toward and away from the ball during valve operation, then sealing is facilitated, but mechanical complexity increases due to retention mechanisms
Solution Approach 1:
The patent implements dynamic sealing by allowing the seat and counterseat to move toward and away from the ball during valve operation. The seat is retained on the ball through a retention mechanism that permits axial movement, while the counterseat is retained in the valve body with similar movement capability. This dynamic arrangement enables the sealing surfaces to maintain optimal contact under varying pressure conditions, improving sealing effectiveness without requiring overly complex retention structures.
Solution Approach 2:
The patent segments the sealing system into separate movable components: the seat carried by the rotatable ball and the counterseat retained in the valve body. Each component is independently retained with mechanisms that allow controlled movement, enabling the sealing surfaces to adapt to pressure changes while maintaining manageable mechanical complexity through modular design.
3Reliability
If differential piston effects are used to enhance sealing pressure, then sealing consistency improves, but contact area reduction increases contact stress and potential for wear
Solution Approach 1:
The patent employs spherical sealing surfaces on both the seat and counterseat to distribute the enhanced sealing pressure uniformly across a broader contact area. The spherical geometry prevents stress concentration that would otherwise occur with reduced contact area, thereby maintaining contact surface durability while benefiting from the improved sealing pressure consistency provided by differential piston effects.
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
This configuration improves sealing consistency, reduces wear, and increases valve cycle life by maintaining a predictable contact area and reducing run torques, while also allowing for smaller actuators and minimizing galling.
Implementation Method 1
allowing for differential piston effects under fluid pressure to enhance sealing pressure and reduce contact area
Implementation Method 2
mechanical retraction mechanisms like retaining caps and pressure-relief ports to manage stress and wear
Data Source
AI summary
Valves having seats and counterseats with various contours are provided. In one embodiment, a valve includes a body and a flow control assembly inside the body. The flow control assembly includes a ball, a seat installed on the ball, and a counterseat. The ball is rotatable between open and closed positions to control flow through the body and the seat and counterseat include mating surfaces that engage when the ball is in the closed position such that the seat seals against the counterseat along the mating surfaces. Further, the mating surface of the counterseat can be a concave surface, the mating surface of the seat can be a convex surface, and at least one of the mating surfaces can have a toroidal contour.