Cryogenic Globe Valve Seat Alignment Under Thermal Contraction
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Solution Overview
Problem
Conventional cryogenic globe valves face issues with high component complexity, thermal contraction leading to gaps and leaks, and difficulty in maintaining high sealing performance due to material differences and temperature-induced shifts, particularly when handling liquefied hydrogen.
Innovation Solution
A cryogenic globe valve design featuring a resin-made valve disk with a conical surface and a through hole, attached to a stem with a fixing member, allowing three-dimensional operation and alignment with the valve seat, ensuring a line contact seal and minimizing gaps even at extremely low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin-made valve disk is used to prevent hydrogen embrittlement, then reliability under cryogenic conditions is improved, but thermal contraction causes gaps between the valve disk and valve seat leading to sealing failure
Solution Approach 1:
The valve disk employs a spherical sealing surface instead of a flat surface. This curvature allows the valve disk to maintain contact with the valve seat even when thermal contraction occurs, as the spherical geometry naturally accommodates dimensional changes while preserving the sealing line contact.
Solution Approach 2:
The patent changes the geometric parameters of the valve disk, specifically introducing a spherical profile with a defined radius of curvature. This parameter modification enables the sealing surface to adapt to thermal contraction effects, maintaining sealing precision despite temperature-induced dimensional changes in the resin material.
2Ease of manufacture
If the valve disk structure is simplified to reduce maintenance, then ease of manufacture is improved, but alignment precision between valve disk and seat deteriorates
Solution Approach 1:
The spherical sealing surface provides self-aligning geometry that automatically compensates for minor misalignments between the valve disk and valve seat. This curved surface design maintains precise alignment without requiring complex adjustment mechanisms or high-precision manufacturing tolerances.
Solution Approach 2:
The spherical geometry enables the valve disk to self-align with the valve seat through its inherent geometric properties. The curvature creates a natural guidance mechanism that automatically positions the sealing surfaces correctly during valve operation, eliminating the need for external alignment devices or complex adjustment procedures.
3Reliability
If multiple components are used to ensure sealing, then sealing performance is improved, but device complexity increases
Solution Approach 1:
The patent merges the sealing function directly into the valve disk structure itself through the spherical surface geometry. This integration eliminates the need for separate sealing components such as gaskets or packing, achieving reliable sealing performance while reducing the total number of parts in the valve assembly.
Solution Approach 2:
The invention extracts the sealing function from separate components and incorporates it directly into the valve disk's geometric design. By embedding the sealing capability in the spherical surface of the valve disk itself, the patent eliminates auxiliary sealing parts and simplifies the overall device structure.
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
Maintains high sealing performance over multiple openings and closings, reduces maintenance needs, and prevents damage to the valve disk and seat surfaces by aligning the seal surfaces correctly, thus ensuring reliable operation and safety.
Implementation Method 1
a degree of freedom for a three-dimensional fine operation required when an alignment effect acts on the valve disk is appropriately ensured
Data Source
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AI summary
To provide a cryogenic globe valve that prevents a high sealing property and safety from being lost even through a large number of times of opening and closing for a cryogenic fluid and is easily maintained, although it has a simple structure. There is provided a cryogenic globe valve having an axial cylindrical portion as a long-neck structure extended to its body, in which a resin-made valve disk having a conical surface having a reduced-diameter tapered shape is attached to a lower end of an elongated stem such that the resin-made valve disk is three-dimensionally operable with respect to the stem even under an extremely low-temperature condition.