Floating Seat Ring Seal Assembly for High-Temperature Class V Shutoff
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Solution Overview
Problem
High temperature pressure-balanced control valves struggle to achieve ANSI/FCI 70-2 Class V shutoff without pilot operated plug designs, which add complexity and cost, due to limitations in dynamic seals that allow fluid bypass at elevated temperatures.
Innovation Solution
A valve assembly with a static seal positioned radially between a floating seat ring and the inner sidewall of the seat-retainer chamber, combined with a dynamic seal on the plug head, ensures tight shutoff by compressing an annular seal spring and C-shaped seal jacket during the closing stroke, eliminating the need for pilot operated elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a dynamic seal is used to seal between the plug and the sleeve in high temperature applications, then the valve can operate at elevated temperatures, but the seal is only capable of providing ANSI/FCI 70-2 Class III or Class IV shutoff and allows fluid bypass
Solution Approach 1:
The sealing system is divided into two independent sealing elements: a dynamic seal (piston ring) for sealing during plug movement, and a static seal (C-shaped seal jacket with annular seal spring) for providing tight shutoff when the valve is closed. This segmentation allows each seal to be optimized for its specific function, enabling Class V shutoff at high temperatures without requiring a pilot operated plug design
Solution Approach 2:
A secondary static seal system (C-shaped seal jacket and annular seal spring) is introduced as an intermediary sealing element that activates when the valve closes. This secondary seal provides the additional leakage path blockage needed to achieve Class V shutoff, working in conjunction with the primary dynamic seal to overcome the dynamic seal's inherent leakage at high temperatures
2Reliability
If a pilot operated plug design is implemented to achieve ANSI/FCI 70-2 Class V shutoff, then tight shutoff is achieved, but the valve includes more components and introduces stability limitations
Solution Approach 1:
The sealing function is segmented between a primary dynamic seal for operational sealing and a secondary static seal system for shutoff. This eliminates the need for pilot operated plug designs with multiple components, achieving Class V shutoff with a simpler two-seal architecture that maintains stability
Solution Approach 2:
The complex pilot operated plug mechanism is extracted and replaced with a simpler static seal system (C-shaped seal jacket and annular seal spring) that provides the same Class V shutoff function without the stability limitations and component complexity of pilot operated designs
3Reliability
If a pilot operated plug design is used to achieve tight shutoff, then Class V shutoff is achieved, but the valve is more expensive
Solution Approach 1:
The expensive pilot operated plug design is extracted and replaced with a cost-effective static seal system consisting of a C-shaped seal jacket and annular seal spring. This alternative approach achieves the same Class V shutoff performance at lower manufacturing cost and without the stability limitations of pilot operated designs
Solution Approach 2:
The static seal components (C-shaped seal jacket and annular seal spring) are designed as simpler, more economical sealing elements that can be easily manufactured and replaced if needed, providing the same shutoff function as expensive pilot operated plugs but at a fraction of the cost
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 configuration provides ANSI/FCI 70-2 Class V shutoff in high temperature applications exceeding 500° F without additional components, enhancing reliability and reducing costs by utilizing a robust static seal that prevents fluid leakage and maintains stability.
Implementation Method 1
compressing an annular seal spring and C-shaped seal jacket during the closing stroke
Implementation Method 2
compressing an annular seal spring and C-shaped seal jacket during the closing stroke
Data Source
AI summary
A valve assembly includes a valve body having a seat-retainer chamber with a floating seat ring disposed adjacent an inner sidewall of the seat-retainer chamber. The floating seat ring is configured to contact a first portion of a plug head at a single annular location prior to a second portion of the plug head contacting a valve primary seat during a closing stroke of the plug head. A static seal is located radially between the floating seat ring and the inner sidewall of the seat-retainer chamber.