For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic-activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation.
The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow non-hermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations.
One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self-energizing and requires low force compared to current pyrotechnic-based burst disk hermetic valves.
This is a novel design for producing a single-use, self-rupturing, hermetically sealed valve for isolation of pressurized gas and/or liquids. This design can also be applied for single-use disposable valves for chemical instruments. A welded foil diaphragm is fully supported by two mated surfaces that are machined to micron accuracies using EDM. To open the valve, one of the surfaces is moved relative to the other to (a) remove the support creating an unsupported diaphragm that ruptures due to over pressure, and/or (b) produce tension in the diaphragm and rupture it.
This work was done by Curtis E. Tucker Jr. and Stewart Sherrit of Caltech for NASA’s Jet Propulsion Laboratory. NPO-47497
This Brief includes a Technical Support Package (TSP).
Self-Rupturing Hermetic Valve
(reference NPO-47497) is currently available for download from the TSP library.
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Overview
The document outlines NASA's innovative Self-Rupturing Hermetic Valve, detailed in Technical Support Package NPO-47497, developed by the Jet Propulsion Laboratory (JPL) at the California Institute of Technology. This valve is designed for use in chemical instruments and addresses the need for a lightweight, reliable, and hermetically sealed isolation valve suitable for one-time use in commercial and aerospace applications.
The key innovation of this valve lies in its novel design, which incorporates a diaphragm supported by two precisely machined surfaces using Electrical Discharge Machining (EDM) technology. This allows for the creation of micro gaps that support the diaphragm until it is intentionally ruptured. The valve can be activated in two ways: by removing the support, which allows overpressure to rupture the diaphragm, or by applying force to the diaphragm itself. This design not only facilitates the controlled release of gases or liquids but also enables the valve to function as a conventional control valve after the hermetic seal is broken, thanks to the potential addition of dynamic seals.
The document emphasizes the valve's applications in micro spacecraft propulsion and in situ instruments that require expendable gases and liquids. The self-rupturing mechanism eliminates the need for penetrations in the valve body, which can lead to leaks, thus enhancing reliability. The valve's disposable diaphragm and the precision of the machined components are highlighted as significant advancements over prior art.
Furthermore, the document acknowledges the research's sponsorship by NASA and its relevance to aeronautical and space activities, indicating the valve's potential for broader technological, scientific, and commercial applications. The Technical Support Package serves as a resource for those interested in the results of aerospace-related developments and encourages collaboration through NASA's Innovative Partnerships Program.
In summary, the Self-Rupturing Hermetic Valve represents a significant technological advancement in valve design, offering a reliable solution for controlled gas and liquid management in various aerospace applications, while also being adaptable for future uses in commercial sectors.
