Bidirectional Shut-Off Trim With Check Valve Pressure Balancing
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Solution Overview
Problem
Current bi-directional pressure balanced valve designs fail under severe service conditions due to rapid erosion and deterioration of sealing areas, making them susceptible to early failure under high temperature and high pressure environments, as existing seal materials are inadequate for maintaining shut-off characteristics.
Innovation Solution
Integration of a spring loaded check valve within the pilot trim, which acts as a normal pilot operated trim in forward flow and balances pressure in reverse flow, eliminating reliance on elastomeric balance seals and allowing the use of carbon or metallic piston rings for enhanced shut-off performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomeric seal materials are used in bi-directional pressure balanced valve designs, then the valve can provide pressure balance during opening and closing movements, but the sealing areas deteriorate rapidly under high temperature and high pressure conditions
Solution Approach 1:
The patent changes the material parameter from elastomeric seals to metal-to-metal sealing surfaces. This fundamental material parameter change eliminates the deterioration issues of elastomeric materials under high temperature and pressure, while maintaining the pressure balance function through the check valve mechanism that allows pressure equalization during valve operation.
Solution Approach 2:
The patent replaces the elastomeric mechanical sealing system with a metal-to-metal sealing system. The check valve mechanism provides pressure balance through fluid mechanics rather than relying on elastomeric deformation, substituting the sealing mechanism to achieve both durability and shut-off characteristics.
2Reliability
If a spring loaded check valve is integrated into the pilot trim, then pressure balance is achieved in reverse flow direction, but the device complexity increases
Solution Approach 1:
The patent merges the check valve function with the existing pilot trim structure. The check valve is integrated into the pilot trim rather than being a separate component, combining pressure balance functionality with the sealing mechanism. This integration reduces the number of separate parts while achieving bidirectional shut-off performance through the unified structure.
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 achieves leak-tight shut-off in both forward and reverse directions, extending the qualified life of equipment and satisfying safety-related isolation functions by eliminating the need for lengthy seal qualification programs and reducing the limitations of elastomeric seals, such as susceptibility to radiation and thermal aging.
Implementation Method 1
the check valve of the shut-off trim opens to balance the pressure on either side of the plug thereof
Implementation Method 2
spring loaded check valve within the pilot trim
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
In accordance with the present invention, there is provided a bi-directional shut-off trim (10) for a valve which possesses the functional attributes of a pilot operated trim and a balanced trim through the integration of a spring loaded check valve into a pilot trim. In forward flow isolation, the bi-directional shut-off trim of the present invention acts as a normal pilot operated trim. In reverse flow, the check valve of the shut-off trim opens to balance the pressure on either side of the plug thereof.