Ball Valve Cradle Assembly for Low-Torque Opening
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Solution Overview
Problem
Ball valve assemblies in subsea operations face challenges in rotating the ball to the open position due to insufficient force from the actuator assembly, often requiring significant above-ball fluid pressure to overcome static friction, which can be inefficient and may not always succeed.
Innovation Solution
The ball valve assembly incorporates a cradle with arms and rotation pins that maintain the ball's position with reduced torque requirements, allowing the ball to rotate efficiently between open and closed positions using pressurized hydraulic fluid and a compression spring as a failsafe mechanism, reducing resistance and enabling easier operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ball is supported between a seal retainer and a cradle with a bushing, then the ball is securely positioned and sealed, but static friction between the ball and bushing prevents the actuator from rotating the ball to the open position
Solution Approach 1:
The patent changes the bushing from a stationary component to a movable one that can be displaced axially. When fluid pressure exceeds a threshold, the bushing moves to disengage from the ball, dynamically reducing friction and enabling rotation. This resolves the contradiction by making the support system adaptive rather than static.
Solution Approach 2:
The patent introduces a pressure threshold parameter that triggers a state change in the bushing position. Below the threshold, the bushing engages for secure positioning; above the threshold, it disengages to enable rotation. This parameter-based control resolves the contradiction between secure positioning and ease of rotation.
2Ease of operation
If significant above-ball fluid pressure is applied to drive the ball to the open position, then the ball can overcome static friction, but the system becomes inefficient and may not always succeed
Solution Approach 1:
The patent replaces the purely mechanical actuator system with a hybrid system that incorporates fluid-actuated bushing displacement. Instead of relying solely on high fluid pressure to overcome friction, the system uses moderate pressure to displace the bushing, which then mechanically disengages to enable rotation. This substitution reduces energy loss and improves reliability.
3Stability of the object's composition
If the ball is engaged with the bushing for secure support, then the ball remains stable in position, but the actuator assembly cannot provide sufficient force to rotate the ball due to static friction
Solution Approach 1:
The bushing is designed to transition from a static engaged state to a dynamic displaced state. This dynamic behavior allows the system to maintain stability when needed while eliminating force transmission barriers when rotation is required, resolving the contradiction between stability and force transmission.
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
This design reduces the torque needed to rotate the ball, enhances the reliability of the ball valve assembly by providing a failsafe closed mechanism, and allows for efficient fluid flow control with reduced resistance and potential for debris passage.
Implementation Method 1
a compression spring configured to urge the ball toward the closed position
Implementation Method 2
allowing the ball to rotate efficiently between open and closed positions using pressurized hydraulic fluid
Implementation Method 3
a cradle with arms and rotation pins that maintain the ball's position with reduced torque requirements
Data Source
AI summary
A ball valve assembly includes a ball configured to rotate between an open position and a closed position. The ball valve assembly also includes a cradle having a ball-facing surface. The ball-facing surface faces the ball and is positioned at an end of a fluid passage through the cradle. In addition, the cradle is configured to rotatably support the ball to enable the ball to rotate between the open position and the closed position, and the cradle is configured to block movement of the ball toward the ball-facing surface to establish a separation distance between the ball and the ball-facing surface.