Spherical Ball Valve Seat Geometry for Wear-Resistant Sealing
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Solution Overview
Problem
Conventional valve devices experience premature wear of the valve seat, leading to sealing issues and potential leakage due to the sliding contact between the ball face and seat face, with the seat face wearing faster than the ball face, and the increased number of components and axial length of the cylindrical portion contributing to these problems.
Innovation Solution
A valve device design featuring a ball valve with a convex spherical ball face and a valve seat with a concave spherical seat face, where the diameter of the seat opening is smaller than the valve opening, and the curvature radius of the ball face is smaller than or equal to the seat face, ensuring different contact sites at opening and closing, reducing wear and maintaining sealing effectiveness over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve seat is pressed onto the ball face with sliding contact for rotation, then the valve can switch communication and non-communication between valve opening and seat opening, but the seat face is susceptible to wear and loses sealing property over time
Solution Approach 1:
The invention applies spherical geometry to both the ball face and seat face, creating a point contact rather than sliding contact. The ball face has a spherical outer surface and the seat face has a spherical inner surface with matching curvature radii, allowing the ball valve to rotate on the seat face without relative sliding, thereby eliminating wear and maintaining sealing property throughout the service life.
2Ease of manufacture
If a cylindrical portion is used to attach the valve seat to the holding member, then the valve seat can be assembled, but the number of components increases and the axial length increases
Solution Approach 1:
The invention merges the valve seat body with the attachment structure by integrating the spherical inner surface directly into the valve seat body. The valve seat is formed as a single piece with the spherical seat face, eliminating the need for separate cylindrical attachment portions and reducing the total number of components while maintaining assembly capability.
3Ease of manufacture
If the cylindrical portion forms an annular groove receiving the valve seat, then the valve seat can be held, but the axial length of the cylindrical portion is larger than the thickness of the valve seat
Solution Approach 1:
The invention combines the attachment function into the valve seat body itself through the spherical inner surface geometry. The valve seat body integrates both the sealing function (spherical seat face) and the attachment function (spherical inner surface for receiving the ball face), eliminating the need for a separate cylindrical portion with annular groove, thereby reducing the axial length to match or be less than the valve seat thickness.
Data Source
AI summary
A valve device includes: a ball valve having a ball face shaped in a convex spherical surface; and a valve seat having a seat face shaped in a concave spherical surface. The seat face is pressed onto the ball face. The ball valve is rotated to open a valve by communicating a valve opening defined in the ball valve and a seat opening defined in the valve seat with each other, and to close the valve by stop the communication. A diameter of the seat opening Φ2 is smaller than a diameter of the valve opening Φ1. A curvature radius of the ball face R1 is smaller than or equal to a curvature radius of the seat face is R2.