Ball Valve Leading-Edge Geometry for Wireline Cutting and Seal Integrity
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Solution Overview
Problem
Ball valve assemblies in subsea oil and gas operations face issues with the deformation of the leading edge when cutting wirelines or coil tubing, which can lead to undesirable stress on the seal, reducing its effectiveness and causing fluid flow blockages.
Innovation Solution
The design incorporates a ball valve assembly with a leading edge configuration where the first leading edge, responsible for cutting the line, is positioned radially inward from the second leading edge, which engages the seal, minimizing the likelihood of deformation and maintaining seal integrity by reducing contact between the deformed edge and the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ball rotates to the closed position to block fluid flow, then fluid flow is blocked, but the leading edge deforms when cutting wireline or coil tubing, causing undesirable stress on the seal and reducing seal effectiveness
Solution Approach 1:
The ball is segmented into distinct functional zones: a leading edge portion for cutting wireline/coil tubing and a seal engagement portion for contacting the seal. This segmentation allows the leading edge to deform during line cutting without transmitting stress to the seal, as the deformation is isolated to the leading edge portion that does not contact the seal during normal operation.
Solution Approach 2:
The cutting function is extracted from the seal engagement function. The leading edge is designed as a separate functional element dedicated to cutting wireline or coil tubing, while the seal engagement portion is designed separately for reliable seal contact. This extraction ensures that deformation from cutting operations does not affect seal effectiveness.
2Ease of operation
If the leading edge is used to cut wireline or coil tubing, then the ball can transition to closed position, but the deformation of the leading edge applies undesirable stress to the seal
Solution Approach 1:
Different portions of the ball are given different properties: the leading edge portion is designed for cutting operations with geometry suitable for severing wireline or coil tubing, while the seal engagement portion is designed with smooth, seal-friendly surfaces. The leading edge may have a more aggressive geometry for cutting, while the seal engagement portion maintains integrity for reliable sealing.
Solution Approach 2:
The ball structure acts as an intermediary that separates the cutting action from the seal engagement. The leading edge portion performs the cutting function as an intermediary step, and through proper geometric design, ensures that even if deformation occurs during cutting, it does not directly transmit to the seal engagement portion.
3Reliability
If the leading edge contacts the seal during rotation, then the ball can seal effectively, but the deformed leading edge reduces seal effectiveness
Solution Approach 1:
The ball is divided into a leading edge portion and a seal engagement portion. The seal engagement portion is specifically designed to contact the seal with precise geometry, while the leading edge portion handles the cutting function. This segmentation ensures that only the precisely engineered seal engagement portion contacts the seal, maintaining sealing effectiveness.
Solution Approach 2:
Instead of having the leading edge contact the seal, the design inverts the sequence and function: the leading edge is designed to cut the line first, and a separate seal engagement portion is designed to contact the seal. This inversion ensures that the element designed for sealing (the seal engagement portion) is the one that contacts the seal, not the element designed for cutting (the leading edge).
Data Source
AI summary
A ball valve assembly includes a ball having a fluid pathway and a leading edge portion. The ball is configured to rotate between an open position and a closed position, the fluid pathway is configured to align with a fluid passage while the ball is in the open position, and the fluid pathway is configured to be offset from the fluid passage while the ball is in the closed position. Furthermore, the leading edge portion includes a first leading edge configured to cut a line extending through the fluid pathway as the ball rotates from the open position to the closed position, the leading edge portion includes a second leading edge configured to engage a seal of the ball valve assembly as the ball rotates from the open position to the closed position, and the first leading edge is positioned radially inward from the second leading edge.