Bowed Eccentric Plug Valve Seat for High-Pressure Sealing
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Solution Overview
Problem
Conventional eccentric plug valves face high friction and increased costs due to the need for expensive actuators when installed in high-pressure systems with the seat on the inlet side, as they suffer from deflection and leakage, necessitating thicker plugs or seats that exacerbate friction.
Innovation Solution
The design incorporates a bowed plug or seat shape to compensate for deflection, maintaining a fluid-tight seal without significantly increasing friction, allowing for a more cost-effective actuator by using an inwardly or outwardly bowed plug or seat configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the seat is positioned on the inlet side in high-pressure systems, then solid build-up is prevented, but plug deflection causes leakage and requires thicker plugs that increase friction
Solution Approach 1:
The plug face is given a bowed (curved) configuration that pre-compensates for the elastic deflection that occurs under high pressure. This curvature is designed to flatten under pressure, maintaining uniform contact with the seat and preventing leakage without requiring increased plug thickness that would exacerbate friction.
Solution Approach 2:
The plug geometry is modified by introducing a specific bowing parameter that changes the contact pressure distribution. Under high pressure, the bowed plug deflects to achieve optimal contact with the seat, dynamically adjusting the contact parameters to maintain sealing while preventing solid accumulation.
2Reliability
If the plug face is made thicker to prevent deflection and leakage, then sealing reliability improves, but friction between plug and seat increases significantly
Solution Approach 1:
Instead of increasing plug thickness, the solution uses a bowed face geometry that provides the necessary structural compliance under pressure. The curvature allows the plug to maintain contact pressure for sealing while remaining thin enough to minimize friction, resolving the contradiction between sealing reliability and friction reduction.
Solution Approach 2:
The plug is constructed using composite materials with optimized mechanical properties that provide sufficient stiffness to maintain shape while allowing controlled elastic deflection for sealing. This enables adequate sealing performance without the excessive thickness that would increase friction.
3Ease of manufacture
If conventional flat plug and seat design is used in high-pressure systems, then manufacturing is simpler, but plug deflection under pressure causes leakage
Solution Approach 1:
The bowed plug face introduces a geometric feature that compensates for pressure-induced deflection. While slightly more complex to manufacture than a flat surface, the curvature can be achieved through standard forming processes and provides significant improvement in sealing reliability under high pressure conditions.
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
The bowed design reduces friction and prevents solid build-up, enabling the use of less expensive actuators while maintaining a fluid-tight seal in high-pressure systems, thus reducing overall manufacturing costs.
Implementation Method 1
the plug 10 suffers deflection (i.e., an elastic deformation of the material of the plug 10) at its center due to the high pressure exerted on its face
Implementation Method 2
The purpose of the eccentric path is to allow the plug 10 to rotate with no contact with the valve seat 11 until it turns within a few degrees of the shut off position. This reduces friction while the plug is rotating
Data Source
AI summary
An eccentric plug valve has a valve body having a cavity between a first fluid passage port and a plug engaging fluid passage port positioned within the valve body to define a fluid flow path with a central axis through the cavity. The valve includes a plug located within the cavity configured to rotate between a fully open position and a fully closed position about an axis that is eccentric relative to the fluid flow path. The valve includes a plug seat on the plug engaging fluid passage port that is configured to engage the plug when it is in the fully closed position preventing fluid flow though the eccentric plug valve by being shaped to compensate for deflection of the plug while the valve is closed to facilitate more uniform friction along the surfaces of the plug and plug seat.