LAUSR

Viton O-ring gaskets are frequently used in high vacuum for demountable flange and vacuum valve seals. Atmospheric gases, particularly water vapor from humid air, permeate through Viton gaskets and thus limit the lowest attainable pressure level in vacuum systems. In this work, a comparison of a vacuum degassed Viton O-ring gasket and a gasket fully saturated with atmospheric gases was performed. A reference measurement with an alternative soft metal gasket for Klein Flange type flanges was also made. The permeation rate of each individual gas from the atmosphere (water vapor, N2, O2, Ar, and CO2) through the Viton O-ring was measured using quadrupole mass spectrometry. The partial gas flow curves Q(t) were also modeled using finite difference modeling (FDM). Using FDM, one can determine the diffusion constant, permeability, and solubility of the gas in the material.