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OmniSafe Particle Study – Stainless Steel Gaskets
Stainless steel gaskets are required in certain gas systems such as carbon monoxide, ozone, and trimethyl arsenic. Because SS gaskets are harder than nickel, the torque induced problems of sealing and galling are amplified. Due to the SS sealing problems, some companies have specified silver plated SS gaskets to reduce friction and galling. Recently these…
The Mechanics of Metal Seal Formation
Tribology is the study of friction, lubrication, and wear. Formally defined, it is the science and technology of interacting surfaces in relative motion. A face seal fitting that transfers torque to the sealing surfaces during the compression that creates the seal, has a fundamental flaw. A tribological study of metal seals shows that this rotation…
OmniSafe Fittings in Space
Flight Qualified – Multi Mate/Demate – Metal Face Seal Fitting Global Observer – hydrogen powered, fuel system, UAV MSL Mars Rover – launch 2011, for the liquid Freon heat rejection system, Omnisafe 3/8” fittings JPL DAWN – Xenon Ion Propulsion, Asteroid Belt, Oct 2007, Omnisafe 1/8” fittings NASA Evolutionary Xenon Thruster (NEXT) Program –…
OmniSafe Cross Section – Finger Tight
This is the cross sectional view of the Omnisafe fitting at finger tight (click to enlarge). The gap between the torque eliminators is the same as the gasket thickness (.028”). If the gasket is missing, the torque eliminators bottom out into a “fail safe” mode. This prevents torroid to torroid contact and destruction. The fitting…
Metal Face Seal Fitting Field Study
Multi Mate-Demate Record This report details a Multi mate/demate field study at Lawrence Livermore National Laboratory. Over six years in service, this fitting was mate/demated 1557 times and was still working effectively when decommissioned. This evaluation shows the direct cost savings by avoiding the replacement of fittings that no longer passed leak check in this…
Counter Rotational Displacement – Standard VCR vs. OmniSafe
How much rotation is transferred to the components connected by a “VCR type”* metal face seal fitting as it is tightened with a nickel gasket? This data below shows that the relative rotation of the components ranges from 6.7 to 18.2 degrees. This rotation is based on the plating inside the female nut and the…