Axially Actuated Ball Valve for Double Positive Isolation
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Solution Overview
Problem
Existing ball valves face challenges in achieving reliable double positive isolation seals, especially in high-pressure and high-temperature environments, due to reliance on fluid pressure for sealing, which can lead to leakage and require large footprints or weights, and existing solutions like expanding plug valves are not suitable for such conditions.
Innovation Solution
A valve assembly with a spherical valve member that uses mechanical seating and angled surfaces within a tapered cavity to create a double positive isolation seal, combining block and bleed techniques with double isolation and bleed, allowing the valve ball to move axially and rotate to enhance sealing without relying solely on fluid pressure, and incorporating features like metal wedge rings and trunnion designs for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fluid pressure is used to bias seals to seat in existing ball valves, then the sealing mechanism is simple, but the sealing reliability deteriorates in high-pressure and high-temperature environments
Solution Approach 1:
The sealing mechanism is divided into two independent seal assemblies: a first seal assembly on the upstream side and a second seal assembly on the downstream side. Each seal assembly operates independently with its own sealing surfaces, allowing the valve to achieve double positive isolation sealing where both seals must fail simultaneously for leakage to occur, thereby significantly improving sealing reliability in high-pressure and high-temperature environments
Solution Approach 2:
Instead of relying on downstream fluid pressure to bias seals as in conventional valves, this invention uses upstream fluid pressure applied to the trunnion to enhance sealing force. The trunnion acts as a pressure-actuated element that converts upstream pressure into mechanical force to press the sealing surfaces together, inverting the traditional pressure-actuation direction and improving seal reliability
2Reliability
If double positive isolation sealing is achieved using conventional methods, then sealing reliability improves, but the valve footprint and weight increase
Solution Approach 1:
The valve merges multiple functions into a single integrated body: the double positive isolation sealing, the pressure-actuated trunnion mechanism, and the flow control function are all combined in one valve assembly. This eliminates the need for multiple separate valves or complex external actuation systems, achieving reliable double sealing while maintaining a compact size and reduced weight
Solution Approach 2:
The trunnion serves multiple functions simultaneously: it acts as a support element for the ball, a pressure-actuated element for enhancing sealing, and a mechanical linkage for ball rotation. This multi-functionality reduces the number of separate components needed, thereby reducing overall valve weight and footprint while maintaining sealing reliability
3Device complexity
If conventional ball valves are used in high-pressure environments, then the valve structure is simple, but leakage occurs due to seal failure
Solution Approach 1:
The valve incorporates a vent cavity that allows pressure equalization and seal testing before full operation. The cavity can be vented to detect seal integrity issues beforehand, and the gradual pressure buildup provides a cushioning effect that prevents sudden seal failure, thereby preventing leakage before it occurs in high-pressure environments
Solution Approach 2:
The high upstream pressure that would normally challenge seal integrity is converted into a beneficial force by applying it to the trunnion, which then uses this pressure to enhance the sealing force. The harmful high-pressure condition is transformed into a mechanism that actively improves sealing performance and prevents leakage
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 enables a compact, reliable double positive isolation seal capable of withstanding high pressures and temperatures, reducing the size and weight of the valve assembly while maintaining effective sealing, even in demanding environments.
Implementation Method 1
The cavity of the valve body may enable the substantially spherical valve member to move axially within the cavity to engage seats, which may enhance a seal formed by the valve assembly
Implementation Method 2
fluid pressure applied to the valve ball may both contribute to establishing and maintaining the seal
Data Source
AI summary
The disclosed embodiments relate to a valve assembly that includes a valve body that has a cavity having one or more seating surfaces, a ball body disposed within the valve body and configured to engage the one or more seating surfaces to form a seal, and an actuator configured to drive the ball body in a first axial direction along a central axis of the cavity to wedge the ball body against the one or more seating surfaces to form the seal, and where the actuator is configured to move the ball body in a second axial direction along the central axis to unseat the ball body and to rotate the ball body about the central axis between an open position and a closed position.