Two dynamic comparison methods for calibrating the rate of pressure leaks

In this paper, two dynamic comparison methods are introduced, namely, a dyn amic comparison method with a reference leak, and a dynamic comparison meth od with quantitative gas. The methods can calibrate gas flow rates or leak rates from 1x10(-2) to 1 x 10(-7) Pa m(3)/s, referenced to a downstream pre ssure of atmospheric pressure. In the dynamic comparison method with a refe rence leak, test gas from the unknown pressure leak or from a reference pre ssure leak is accumulated for different times such that a similar quantity of test gas is introduced into a vessel filled with atmosphere. The mixed g as is then expanded and the expanded gas is introduced into a dynamic flow system. The dynamic balance partial pressure of the test gas is then measur ed and compared. In the dynamic comparison method with a reference gas, a k nown quantity of gas is used instead of the accumulated test gas through a reference pressure leak. (C) 1999 Elsevier Science Ltd. All rights reserved .