Subsea Valve Stem Seal Arrangement Reducing Leakage Paths
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Solution Overview
Problem
Current subsea valve stem seal arrangements are complex, with multiple seal designs and geometries, leading to numerous leakage paths, making testing, qualification, and maintenance difficult, and resulting in reduced service life and increased dimensions.
Innovation Solution
A simplified valve stem seal arrangement with identical inner and outer seal diameters between the stem and bonnet, supported by a combination of inclined support rings and retainer rings, reducing the number of seal geometries and leakage paths, and enhancing the ability to handle high pressures without material extrusion or fluid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple seal designs and geometries are used in the valve stem seal arrangement, then sealing reliability against high pressure is improved, but device complexity and number of leakage paths increase
Solution Approach 1:
The patent combines multiple sealing functions into a single integrated seal carrier assembly that houses both primary and secondary seals. The seal carrier integrates seal retention, positioning, and support functions that were previously distributed across multiple separate components, thereby reducing overall device complexity while maintaining multi-layer sealing protection against high pressure.
Solution Approach 2:
The seal carrier is designed as a multi-functional component that simultaneously performs seal retention, structural support, leakage path containment, and positioning of multiple seals. This universal component replaces what would otherwise require several separate parts, reducing complexity while preserving the reliability benefits of multiple sealing layers.
2Reliability
If multiple seal designs and geometries are used in the valve stem seal arrangement, then sealing coverage is improved, but testing and qualification difficulty increases
Solution Approach 1:
By combining multiple seals into a single integrated seal carrier assembly, the patent creates a unified testing target. This allows quality assurance teams to test and qualify the entire sealing system as one assembly rather than individually testing each separate seal component, significantly reducing the complexity of detection, measurement, and qualification processes while maintaining comprehensive sealing coverage.
3Reliability
If multiple separate seal components are used, then sealing redundancy is improved, but maintenance and replacement complexity increases
Solution Approach 1:
The patent merges multiple seal components into a single replaceable seal carrier assembly, which maintains sealing redundancy through integrated primary and secondary seals. During maintenance, the entire seal carrier can be replaced as one unit rather than requiring disassembly and replacement of multiple individual seal components, significantly simplifying maintenance procedures while preserving the redundancy benefits of multi-layer sealing.
4Manufacturing precision
If a carrier is used to hold the secondary seal, then seal positioning is improved, but number of static seals and leakage paths increases
Solution Approach 1:
The patent integrates the seal carrier design to combine seal positioning and seal retention functions into a single structural component. The carrier is designed with integrated features that simultaneously provide precise positioning for both primary and secondary seals while containing their respective leakage paths, thereby achieving accurate seal positioning without proportionally increasing the number of separate sealing components and leakage paths.
Data Source
AI summary
The invention provides a valve useful as a production valve in or connected to a production tree subsea, and other similar uses subsea or topside, the valve comprises a valve element, a valve element pressure housing, an actuator, a stem and a bonnet, the actuator is via the stem operatively arranged to close or open a fluid passageway through the valve element, the bonnet enclose the stem and is connected to the valve element pressure housing and seals are arranged between the stem and the bonnet for sealing against the pressure of the valve element pressure housing. The valve is distinctive in that the valve comprises at least one seal for sealing between stem and bonnet, the seal having identical inner sealing diameter against the stem and outer sealing against a single body or element of the bonnet.