Determination of permeation constants for gases through teflon hose walls.

摘要

Teflon hoses are used on the International Space Station. Acceptance tests are performed to ensure that hoses do not leak beyond an acceptable leak rate, which may cause performance or safety concerns. The Helium bell jar and Helium and Nitrogen pressure decay leak tests are performed. In some cases, the test is performed using one gas and the results need to be converted to another gas. This thesis provides a comparison of the test methods used to measure leak rate and obtain the permeation constants, including uncertainty, and an analysis of the leak rate conversion ratio from Helium to Nitrogen. The testing demonstrated viable methods for obtaining relatively accurate results and provided helpful insight into the causes of overall uncertainty. Comparable leak rate uncertainties were obtained for the two test methods. The data obtained will provide results that are within ½ a decade of the actual leak rate.