Eccentric Valve Tri-Offset Seal Manufacturing Method
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Solution Overview
Problem
Conventional eccentric valves with tri-offset structures face manufacturing difficulties due to the need for radially asymmetric seals, which are challenging to produce and require directional alignment, leading to potential leakage during assembly.
Innovation Solution
The design features a centrosymmetric ring seal with a cambered surface and a valve seat with an oblique cone surface, allowing for non-directional engagement and assembly, with the seal's curvature determined by tangency points on radial cross-sections to ensure tight sealing without gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radially asymmetric seal is used to achieve tight sealing in the tri-offset structure, then the sealing performance is improved, but the manufacturing difficulty increases and directional alignment is required
Solution Approach 1:
The patent applies asymmetry by designing the seal with a radially asymmetric cross-section where one end has a larger diameter than the other end. This asymmetric geometry enables the seal to conform to the tapered inner surface of the valve seat, achieving tight sealing in the tri-offset structure while the patent addresses the manufacturing challenge through specific geometric definitions
Solution Approach 2:
Instead of making the valve seat asymmetric to match the seal, the patent inverts the approach by making the seal asymmetric to match the symmetric tapered valve seat. This inversion simplifies the valve seat manufacturing while maintaining sealing effectiveness through the asymmetric seal geometry
2Reliability
If a radially asymmetric seal is used to achieve tight sealing, then the sealing performance is improved, but the assembly complexity increases due to directional alignment requirements
Solution Approach 1:
The asymmetric seal geometry with different diameters at each end creates a natural orientation requirement, ensuring proper installation direction. The larger-diameter end contacts the tapered valve seat surface while the smaller-diameter end faces outward, providing inherent alignment guidance during assembly
3Ease of operation
If the seal slides during assembly to achieve positioning, then the assembly process is simplified, but the tight sealing is damaged causing leakage
Solution Approach 1:
The patent employs curved cambered surfaces on the seal with specific radius of curvature that work in conjunction with the tapered valve seat. The curved geometry of the seal's outer surface and the tapered inner surface create a self-aligning mechanism that positions the seal correctly without sliding, preventing sealing damage
Data Source
AI summary
Provided is a method of manufacturing an eccentric valve of a tri-offset structure including a valve body, a valve seat, a valve unit, and a valve stem. The method includes steps of providing a seal being a centrosymmetric ring with an outer edge surface being a cambered surface with a fixed curvature; disposing the seal on an annular surface of the valve unit; enabling the disposal position of the seal on the annular surface to deviate from the disposal position of a pair of second shaft holes provided in a longitudinal direction of the valve unit.