Bidirectional Ball Valve Sealing Under Ultra-High Pressure
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Solution Overview
Problem
Ball valves experience operational issues due to leaking past seals, particularly under high pressure and temperature conditions, which are common in various industrial processes.
Innovation Solution
A bidirectional ball valve design featuring a flow control assembly with a rotatable flow control element that engages with valve seats, allowing for lateral movement to establish sealing contact, and a valve stem with a packing bore system using thermoplastic and sealing rings to maintain sealing under extreme pressures and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ball valve seal design is used, then the valve structure is simple, but leaking occurs under high pressure and temperature conditions
Solution Approach 1:
The flow control element is designed with lateral mobility relative to the valve stem, allowing it to dynamically adjust its position in response to pressure differentials. This dynamic positioning enables the sealing surfaces to maintain contact under varying high pressure and temperature conditions, resolving the contradiction between sealing reliability and structural simplicity.
Solution Approach 2:
The valve incorporates self-adjusting sealing mechanisms where pressure differential automatically positions the flow control element against the appropriate valve seat. The design uses the process fluid's own pressure to achieve and maintain sealing contact without requiring external actuation or complex control systems.
2Reliability
If the flow control element is fixed to the valve stem, then the valve structure is simple, but sealing contact cannot be established under high pressure
Solution Approach 1:
The flow control element is decoupled from fixed positioning relative to the valve stem, allowing it to laterally move and rotate independently. This dynamic capability enables the element to automatically establish sealing contact with the valve seat under high pressure conditions while maintaining rotational control through the valve stem's angular positioning.
Solution Approach 2:
The valve assembly is segmented into independently movable components: the valve stem for angular rotation, the flow control element for lateral movement and sealing contact, and the valve body for structural support. This segmentation allows each component to perform its specific function optimally without constraining the others.
3Reliability
If sealing surfaces are made larger to improve sealing, then sealing reliability improves, but the valve size and complexity increase
Solution Approach 1:
The sealing effectiveness is achieved through optimizing the contact pressure and surface geometry parameters rather than increasing seal size. The flow control element's lateral movement capability allows concentrated sealing force on precisely positioned surfaces, maintaining effective sealing with compact dimensions.
Solution Approach 2:
The sealing system uses the process pressure itself to generate the necessary contact force between sealing surfaces. The pressure differential automatically pushes the flow control element against the valve seat, eliminating the need for oversized seals or additional spring loading mechanisms.
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 design effectively prevents fluid leakage at pressures over 275.8 MPa (40,000 psi) and temperatures of at least 200°C for extended periods, ensuring reliable operation in high-pressure and high-temperature environments.
Implementation Method 1
a distance between the sides of the recess are dimensioned relative to a distance between the plurality of sides of the first end of the valve stem to allow for an amount of lateral movement of the flow control element laterally between the fluid flow bore inlet end and the fluid flow bore outlet end such that a pressure applied to the inlet end of the fluid flow bore results in lateral movement of the flow control assembly towards the outlet end of the fluid flow bore in an amount sufficient to produce sealing contact between an outer annular surface of the outlet valve seat with a portion of the valve body
Data Source
AI summary
A ball valve for ultra-high pressure applications wherein the inner annular surface(s) of the valve seat(s) has an annular sealing face in sealing engagement with the flow control element, support surfaces adjacent the sealing face in contact with the flow control element, and vent grooves between adjacent support surfaces and between the sealing face and the support surfaces. A method to utilize the bidirectional ball valve involves rotating the valve stem and control element and maintaining a pressure of 275.8 MPa (40,000 psi) or more for at least 1 hour without leaking before opening or after closing the valve.