Double Eccentric Valve Sealing Geometry
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Solution Overview
Problem
The double eccentric valve experiences deterioration in valve-opening response and durability due to abrasion between the valve seat and element, and fails to ensure appropriate fluid flow characteristics as the valve opens, primarily because of the elastic member's presence and the geometry of the valve elements.
Innovation Solution
The valve element is partitioned into two regions with specific rotation paths, and the seat surface is inclined to minimize contact and friction, allowing the valve to rotate without an elastic member, ensuring sealing in the closed state and improved flow characteristics by maintaining the first shortest distance equal to or greater than the second shortest distance and the first passage area 1.3 times larger than the second passage area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastic member is provided to press the valve seat against the valve element for sealing, then sealing performance is improved, but the number of components increases and structure becomes complicated
Solution Approach 1:
The invention removes the elastic member from the valve structure entirely. Instead of using an elastic member to press the valve seat against the valve element, the design relies on the double eccentric geometry and fluid pressure to achieve sealing, thereby reducing the number of components and simplifying the structure while maintaining sealing performance
Solution Approach 2:
The valve structure uses itself to achieve sealing through its geometric configuration. The double eccentric arrangement creates a self-centering effect where the valve element naturally contacts the valve seat at specific points during rotation, and fluid pressure enhances this self-sealing mechanism without requiring external elastic components
2Reliability
If the valve seat is pressed against the valve element by the elastic member, then sealing performance is improved, but the valve seat and valve element rub against each other during opening, deteriorating valve-opening response and durability
Solution Approach 1:
By removing the elastic member, the invention eliminates the continuous pressing force that causes rubbing and wear during valve operation. The sealing contact occurs only when necessary (in the closed position), rather than being maintained by constant elastic pressure throughout the valve's movement cycle
Solution Approach 2:
The sealing mechanism transitions from static continuous contact (maintained by elastic pressure) to dynamic intermittent contact. The valve element contacts the valve seat only during the closed position and brief transition periods, allowing the valve to open and close with minimal friction and wear, thereby improving durability and response time
3Productivity
If the valve element rotates from fully closed position, then the valve opens to allow fluid flow, but the sealing surface contacts the seat surface at an early stage causing abrasion and wear
Solution Approach 1:
The double eccentric configuration creates a dynamic sealing pattern where the valve element rotates without continuous contact with the valve seat. The sealing surfaces engage only at specific angular positions during the rotation cycle, minimizing the duration and intensity of contact, thereby reducing abrasion and wear while maintaining effective fluid flow control
Data Source
AI summary
A double eccentric valve includes a valve seat having a seat surface, a valve element having an annular sealing surface, and a rotary shaft having an axis parallel to a radial direction of the valve element and offset from the center of a valve hole in a radial direction thereof. The sealing surface is positioned eccentrically from the axis toward an extending direction of an axis of the valve element. The valve element rotates about the axis of the rotary shaft between a fully-closed position in which the sealing surface is in surface contact with the seat surface and a fully-open position in which the sealing surface is furthest away from the seat surface. Simultaneously with start of rotation of the valve element from the fully-closed position, the sealing surface starts to separate from the seat surface and also move along rotation path about the axis of the rotary shaft.