Cryogenic Two-Way Ball Valve With Single-Seat Sealing
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Solution Overview
Problem
Conventional ball valves fail to maintain a tight seal at cryogenic temperatures due to material hardening and deformation, leading to leaks and potential overpressure issues when used in two-way configurations.
Innovation Solution
A two-way ball valve design with a single closing seat that uses a sealing gasket with annular lips and springs to ensure tight sealing in both directions, incorporating recesses to manage fluid pressure and prevent overpressure, ensuring contact between the gasket and the valve body and ball despite material deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional elastic gasket is used as a closing seat, then the valve can adapt to irregularities in the ball shape at normal temperatures, but at cryogenic temperatures the gasket hardens and loses elasticity, causing sealing failure
Solution Approach 1:
The patent changes the material parameter of the closing seat from elastic material to a material with linear thermal expansion coefficient matched to the ball material. This allows the closing seat to maintain dimensional stability and sealing capability across the full temperature range from cryogenic to normal operating conditions, eliminating the hardening issue of conventional elastic gaskets.
Solution Approach 2:
The patent uses a composite structure where the closing seat is made of a material specifically selected to have thermal expansion characteristics that match the ball material. This composite approach combines materials with complementary properties to achieve both structural integrity and sealing performance across extreme temperature variations.
2Reliability
If closing seats are positioned in both inlet and outlet ducts of a two-way valve, then sealing in both directions is achieved, but fluid becomes trapped in the inner cavity causing overpressure that the closing seats cannot retain
Solution Approach 1:
The patent extracts the problematic inner cavity from the valve design by positioning the closing seat to eliminate the enclosed space where fluid could become trapped. By repositioning the closing seat at the contact between the ball and valve body, the design removes the dead space that causes overpressure issues while maintaining bidirectional sealing capability.
Solution Approach 2:
The patent converts the potential harmful effect of trapped fluid into a beneficial pressure distribution by designing the closing seat geometry and positioning such that fluid pressure acts to enhance sealing rather than create overpressure. The single closing seat design allows pressure to be distributed in a way that reinforces the seal while preventing cavity overpressure.
3Ease of manufacture
If a single closing seat is used in a two-way valve, then manufacturing costs are reduced and assembly is simplified, but sealing in both flow directions cannot be ensured
Solution Approach 1:
The patent designs the single closing seat with multi-functional capability to perform sealing in both flow directions. The closing seat is positioned and dimensioned to contact the ball at a location that prevents fluid leakage regardless of flow direction, allowing one component to fulfill the sealing function that traditionally required two separate closing seats.
Solution Approach 2:
The patent merges the function of two separate closing seats into a single closing seat located at the ball-valve body contact interface. This unified closing seat design combines the sealing functions for both inlet and outlet ducts into one component, reducing manufacturing complexity while maintaining bidirectional sealing reliability.
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 achieves a hermetic seal in both directions of fluid flow, reduces manufacturing costs, and prevents overpressure by eliminating dead spaces, maintaining tightness and reducing assembly complexity.
Implementation Method 1
wherein between the wall and said first end there is arranged a spring that presses the annular lip against the wall to close the passage of fluid
Implementation Method 2
at these low temperatures the balls can deform and become oval or irregular because the contraction of the metallic material is not linear or due to the dissimilarity of materials between the ball, valve body and elastic material which all have different mechanical characteristics and contraction/expansion coefficients
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a two-way ball valve with a cryogenic seat, comprising: a valve body (1) with inlet and outlet ducts (2, 2'); a ball (3) with a through hole (3.1); and at least one closing seat (4) in one of the ducts (2, 2') with a closing sealing gasket (5) against the wall (6) of the inner cavity where the ball (3) is arranged, the gasket (5) having a first end (5.2), a second end (5.3), and an intermediate part (5.1) projecting from the housing (7) and contacting the ball (3), the first end (5.2) being arranged in a first chamber (7.1) of the housing with a first annular lip (5.21) contacting the wall (6) by the action of a first spring (8.1) so as to close the passage of fluid from the first duct (2), and the second end comprising a second annular lip (5.31) in contact with the wall (6) by the action of a second spring (8.2) to close the passage of fluid from the second duct (2').