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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Fixture facilitates inspection testing of circumferential pipe welds for vacuum tightness, using helium gas as a leakage tracer in conjunction with a mass spectrometer. It consists of a split rubber torus and a mating clamping ring with a vacuum hose fitting.
Calibrated enclosure system using helium injection method for estimating leakage rates
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Study reveals quantitative measurements of the diffusion of trace gases /Freon and helium/ injected into systems by different methods. Results show that uniform mixing does not always occur, thus evaluation of the system under test and establishment of the method of trace gas injection are mandatory.
Halogen detector for leakage in hermetically sealed devices
Technique for measuring partial pressures utilizes extremely large resonance scattering cross section of xenon at 1471 angstroms to scatter light in a vacuum cell. Output signal of ultraviolet-sensitive photodetector is proportional to the partial pressure and to the rate of inleakage of xenon probe gas.
Valve leakage due to contaminant entrapment and chattering is effectively minimized by a metallic poppet-and-seat check valve designed for use in extreme environmental and fluid temperature conditions.
Detection techniques for hydrogen leakage and fire
Fluid leakage detection system with automatic monitoring capability
Development of device for detecting hydrogen in ambient environments
Data monitoring of gas leakage in satellites and spacecraft is facilitated by adding gaseous radioisotopes to cold compressed gas and mounting a detector in the thrust nozzle.
Ultrasonic detector utilizes set of contact transducers and bandpass filters to detect and analyze sonic energy produced by flow or leakage. Detector covers wide frequency range and is operable at cryogenic temperatures and in vacuum.
A system was developed and applied at the NASA Manned Spacecraft Center for measuring and analyzing directional molecular flows in a large thermal vacuum chamber in order to verify molecular environment and identify characteristic and abnormal test article and chamber conditions. The system is described, and some results obtained in over 1200 hours of operation are given.
Silicone-rubber adhesive is applied externally to seal hair-line cracks in sections of high vacuum system while system is partially evacuated. No pretreatment of surface is required since adhesive will be drawn into crack while diffusion or ion pump is off.
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Zero-leakage valve has fluid-sealing diaphragm support and flat sievelike sealing surface. Diaphragm-support valve is easy to fabricate and requires minimum maintenance. Potential applications include isolation valve for waste systems and remote air-actuated valve. Device is also useful in controlling flow of liquid fluorine and corrosive fluids at high pressures.