Double Piston Trunnion Ball Valve Seal Design
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Solution Overview
Problem
Trunnion-mounted ball valves face challenges in high-pressure applications due to reduced seal reliability and increased torque requirements, leading to potential leakage and operational issues, especially in 'aggressive' wells with high particulate matter.
Innovation Solution
A double piston, trunnion-mounted ball valve design that utilizes bias elements, such as wave springs and Belleville springs, to enhance sealing by applying opposing forces to the ball element, creating a double seal and reducing the impact of high upstream pressures on the downstream seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a floating ball system is used, then seal reliability is improved, but torque requirements increase excessively
Solution Approach 1:
The sealing function is segmented between two separate piston-seal interfaces rather than relying on a single floating ball seal. This distribution of sealing responsibilities reduces the torque required to operate the valve while maintaining high seal reliability through the dual-seal configuration.
Solution Approach 2:
The sealing mechanism transitions from a single-point contact (floating ball) to a distributed dual-piston system with separate upstream and downstream sealing interfaces. This dimensional change in the sealing approach reduces operational torque while improving seal reliability.
2Force
If high pressure is applied on the upstream side, then sealing force increases, but ball deformation occurs leading to leakage
Solution Approach 1:
The high upstream pressure is segmented into two separate sealing zones: an upstream seal handling the high pressure differential and a downstream seal providing secondary containment. This segmentation prevents excessive pressure from deforming the ball at a single interface, maintaining sealing integrity.
Solution Approach 2:
The downstream seal acts as a cushioning backup that prevents leakage before it can occur through the primary seal. This beforehand protection mechanism compensates for any potential ball deformation under high pressure, maintaining sealing integrity.
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 maintains a double seal and reduces the torque required to rotate the ball, enhancing operational reliability and preventing leakage, even in high-pressure conditions.
Implementation Method 1
bias elements, such as wave springs and Belleville springs, to enhance sealing by applying opposing forces to the ball element
Implementation Method 2
bias elements, such as wave springs and Belleville springs
Data Source
AI summary
Disclosed are a method and a ball valve structure which provide for an improved seal in a trunnion mounted, double piston ball valve, which is especially useful in applications requiring a seal against high pressures, such as in the oil, gas and chemical process industries. Higher pressures on an inlet side of the valve are used, while the valve moves toward and is maintained in a valve closed position, to create movement of a ball element of the valve so as to bias the ball element against both piston seat elements (or rings) used to create the seals. This movement of the ball element thereby effectively uses such upstream pressure to create and enhance a seal between the ball element and both piston seat elements while in the valve closed position.