Method of and apparatus for compensating for temperature in leak testing

摘要

A method and apparatus for testing for leaks in a test item which has a temperature different from ambient temperature in which the test item is sealed at atmospheric pressure and the pressure of the sealed air in the test item is measured. The rate of change of the pressure of the sealing air due to the non-ambient temperature of the test item is calculated for providing a temperature correction signal proportional to the temperature of the test item and the temperature correction signal is stored. The test item is then subjected to a leak test pressure, any change in the pressure of the pressurized test item is measured and the stored correction signal is applied to the pressure measurement for determining the extent of any leak in the test item while compensating for the temperature of the test item. The temperature correction signal is obtained by differentiating the pressure measurement of the sealed test item in ambient air at ambient pressure, is stored, is integrated, and is inverted and applied to the pressure measurement obtained during the normal pressure decay test time.