Cryogenic Valve Actuation With Strain Wave Sealing Membrane
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Solution Overview
Problem
Existing valve actuation mechanisms for cryogenic and H2 applications face challenges in providing a gas-tight rotational seal, especially for ball valves, leading to potential leakage issues due to dynamic movements.
Innovation Solution
A valve actuation mechanism utilizing a strain wave gearing system with a flexible sealing membrane that integrates a stationary flexible ring gear as part of the sealing membrane, allowing for rotational movement transmission without relative movement in the seal, thus achieving a gas-tight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dynamic rotational seal is used in conventional valve actuation mechanisms, then rotational movement can be transmitted, but hydrogen leakage occurs due to dynamic movements compromising seal integrity
Solution Approach 1:
The actuation mechanism is divided into two separate sealed chambers: an inner sealed area containing the output shaft and closing element, and an outer sealed area containing the input shaft. The sealing membrane divides these chambers, allowing rotational movement in the outer area while maintaining seal integrity in the inner area where hydrogen is contained.
Solution Approach 2:
A strain wave gearing system acts as an intermediary mechanism between the input shaft and output shaft. This gearing system transmits rotational movement through mechanical engagement of gear teeth on the sealing membrane with corresponding teeth on the output shaft, eliminating the need for a dynamic rotational seal while maintaining vacuum integrity.
2Ease of operation
If a sealing membrane is made flexible to allow strain wave gearing deformation, then rotational movement can be transmitted, but the membrane may compromise its sealing capability
Solution Approach 1:
The sealing membrane has different local properties: the annular wall portion contains gear teeth for mechanical engagement and transmits rotational movement, while other portions of the membrane maintain high sealing capability. The membrane's localized flexibility at the gear engagement area does not compromise its overall sealing integrity.
Solution Approach 2:
The sealing membrane is made from a composite material or structured design combining flexible regions for strain wave gearing engagement with rigid sealing regions. This allows the membrane to deform locally for motion transmission while maintaining global seal integrity against hydrogen leakage.
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 mechanism significantly reduces leakage by maintaining vacuum integrity and ensuring high safety against hydrogen leakage, even with manual or automatic actuation, making it suitable for cryogenic applications.
Implementation Method 1
a stationary flexible ring gear with external teeth which is deformed by the wave generator to engage with internal gear teeth of the outer gear wheel
Implementation Method 2
a housing defining an inner area which is sealed by a sealing membrane from an outer area
Data Source
AI summary
A valve actuation mechanism for actuating a rotatable closing valve element for cryogenic applications and/or H2 applications, including a housing defining an inner area sealed by a membrane from an outer area, an input shaft configured to receive a rotational movement, the input shaft being in the outer area, an output shaft configured to be connected to the closing element, wherein the output shaft is in the inner area, and a strain wave gearing connecting the input and output shafts. The strain wave gearing includes a wave generator connected to one of the input and output shafts, a rotatable outer gear wheel connected to the other one of the input and output shafts and a stationary flexible ring gear with external teeth deformed by the wave generator to engage with internal gear teeth of the outer gear wheel. The flexible ring gear is a portion of the sealing membrane.