Cryogenic Ball Valve Seat Insert With Spring-Biased Sealing
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Solution Overview
Problem
Ball valves experience leakage at cryogenic temperatures due to shrinkage or deformation of seat inserts and other components, leading to fluid loss.
Innovation Solution
A ball valve design featuring a seat insert with angled walls and a spring mechanism that biases the insert against the angled wall, enhancing sealing forces to prevent leakage through multiple paths, even under cryogenic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seat insert is used in a ball valve, then the valve operates normally at ambient temperatures, but leakage occurs at cryogenic temperatures due to shrinkage and deformation of the seat insert
Solution Approach 1:
The patent introduces a spring mechanism that dynamically adjusts the sealing parameters (contact force, position) in response to temperature changes. The spring compensates for dimensional changes in the seat insert at cryogenic temperatures by maintaining adequate contact force between the seal and the ball, thereby preserving sealing performance across a wide temperature range
Solution Approach 2:
The seat insert design transitions from a static sealing structure to a dynamic one where the spring-loaded mechanism actively responds to thermal contraction. The spring allows the seat insert to move and adjust its position and contact force dynamically, accommodating the shrinkage that occurs at cryogenic temperatures while maintaining reliable sealing
2Reliability
If the seat insert is biased against the angled wall to increase sealing force, then leakage prevention improves, but the device complexity increases due to the spring mechanism
Solution Approach 1:
The spring mechanism serves multiple functions simultaneously: it provides the biasing force for sealing, compensates for thermal dimensional changes, and maintains consistent contact pressure across temperature variations. This multi-functionality justifies the added complexity by delivering multiple benefits from a single integrated mechanism
Solution Approach 2:
The spring mechanism is localized to the seat insert assembly where sealing occurs, rather than being a system-wide solution. The angled wall geometry is specifically designed in the local sealing region to work synergistically with the spring, concentrating the complexity only where it is needed to solve the sealing problem
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 angled wall and spring mechanism significantly increase sealing force, reducing leakage by at least 1% to 150% under cryogenic conditions, ensuring a fluid-tight seal.
Implementation Method 1
A spring acting against a fixing plate biases the seat insert against the angled wall
Implementation Method 2
the angled wall drives or forces the seat insert upwards, thereby increasing a sealing force between the seat insert and the angled wall
Implementation Method 3
when a ball valve is subjected to extreme environmental conditions such as cryogenic temperatures, the seat insert and/or other portions of the ball valve may shrink, deform, or otherwise change
Data Source
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AI summary
Systems and methods are disclosed that include providing a valve suitable for maintaining a seal and preventing fluid flow through the valve at cryogenic temperatures. The valve includes a valve body having a longitudinal axis along a flow path through the valve, a ball selectively rotatable within the valve body to selectively allow fluid flow through the valve, a seat formed within the valve body and comprising a cavity having an angled wall, and a seat insert at least partially disposed within the cavity and having a first sealing surface that forms a first sealing interface with the ball to prevent leakage through a first leakage path and a second sealing surface that forms a second sealing interface with the angled wall to prevent leakage through a second leakage path when the ball valve is selectively rotated to prevent fluid flow through the valve.