Measuring gas-air mixture leakage from closed systems - using pressure change and time for reaching conc. equality

摘要

The arrangement is used for determing the leakage of a gas-air mixture from a closed system involve modulating infrared or ultraviolet light by the gas-air absorption characteristic and measuring intensity variations. They are applicable in aircraft, vehicle, chemical, oil and gas industries etc. The instability of conventional arrangements is overcome by determining the leak detector's sensitivity using a control leak. The gas-air mixture is fed to a working chamber until its conc. reaches that in the closed system. The time to achieve this is measured. The change in pressure from the beginning of the time until equality of conc. is reached is measured. The flow, which is a measure of leakage, is derived from the product of the chamber vol. and the pressure change divided by the time interval.