Fluid Valve Seal Assemblies with Dynamic Wedge Sealing
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Solution Overview
Problem
Existing seal assemblies for fluid valves face challenges in preventing fluid leakage and reducing frictional load during throttling conditions, leading to inefficiencies and wear.
Innovation Solution
A seal assembly featuring a flexible graphite core surrounded by a stainless steel housing with a wedge-shaped groove and a back-up ring, utilizing a spring to manage pressure and reduce friction, and a tapered protrusion to ensure sealing engagement with the cage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional seal assembly is used, then the structure is simple, but fluid leakage occurs and frictional load increases during throttling conditions
Solution Approach 1:
The seal assembly is divided into distinct functional segments: a plug with seal gland, a cage with inner surface, and a multi-component sealing mechanism including a first portion and second portion. This segmentation allows each component to perform its specific function optimally while maintaining overall sealing reliability.
Solution Approach 2:
The seal assembly employs composite structural design combining different materials and components - the plug appears to be made of a different material than the cage, and the sealing mechanism uses multiple portions that may be made of different materials to optimize both sealing performance and friction reduction during throttling conditions.
2Ease of manufacture
If the seal assembly uses a simple structure, then manufacturing is easier, but frictional load increases during throttling conditions
Solution Approach 1:
The seal assembly incorporates dynamic response characteristics where the first and second portions can move relative to each other in response to fluid pressure changes during throttling. This dynamic adjustment allows the seal to adapt to varying flow conditions, reducing frictional load while maintaining sealing effectiveness.
Solution Approach 2:
The sealing mechanism changes its physical parameters (position, orientation, contact pressure) in response to fluid pressure changes during throttling operations. The first portion responds to fluid acting in a first direction by engaging and urging the second portion, while fluid acting in a second direction causes the second portion to deter fluid from acting on the first portion, thereby adjusting frictional characteristics.
3Reliability
If the seal assembly is designed for high sealing force, then fluid leakage is prevented, but wear increases during operation
Solution Approach 1:
The seal assembly utilizes periodic or cyclical engagement and disengagement of the first and second portions in response to fluid pressure fluctuations during throttling operations. This periodic action reduces continuous contact and wear while maintaining sealing effectiveness when required.
Solution Approach 2:
The seal assembly introduces an intermediary mechanism between the plug and cage - the multi-component sealing system with first and second portions that can independently respond to fluid pressure. This intermediary structure distributes wear across multiple components rather than creating direct high-stress contact between the plug and cage, thereby extending operational longevity while maintaining leakage prevention.
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 solution effectively prevents fluid leakage and reduces frictional load during throttling conditions, enhancing the operational efficiency and longevity of the seal assembly.
Implementation Method 1
utilizing a spring to manage pressure and reduce friction
Implementation Method 2
in response to a fluid acting on the first portion in a first direction, the first portion to engage, outwardly urge, and splay the second portion to sealingly engage the cage
Data Source
AI summary
Seal assemblies for use with fluid valves are described. An example apparatus includes a cage; a plug including a seal gland; and means for sealingly engaging an inner surface of the cage at least partially positioned in the seal gland and including a first portion and a second portion, in response to a fluid acting on the first portion in a first direction, the first portion to engage, outwardly urge, and splay the second portion to sealingly engage the cage, in response to the fluid acting in a second direction, the second portion to deter the fluid from acting on the first portion, the first direction opposite the second direction.