Leak rate measurement comparisons [package seals

Abstract

Gross leak and fine leak test results on a series of 527 parts were checked by repeating the measurements or by using different test methods to gauge the accuracy of the methods. The parts had a large 17 cm/sup 3/ internal volume and were sealed in a laced sealing ambient using a target value of 10% helium. A spreadsheet was used to compare the initial fine and gross leak data with the verifying tests. The verifying tests consisted primarily of a repetition of the initial ambient gross leak test on all 527 parts and a fine leak test based on the radioisotope method on a sample of 41 parts. These comparisons were made to gauge error rates for the different methods and as a check on the accuracy of the Howl-Mann mass ratio scaling used in the flexible fine leak method.