Detection of gas leakage using microcolor schlieren technique

This article presents microcolor schlieren technique for gas leakage detection with medium of liquefied petroleum gas (LPG, 50% C3H8 and 50% C4H10), which can be further applied in pipe gas leakage inspection, e.g. checking gas leakage of condenser and evaporator pipes of air conditioning in the automatic production line. In this work, experiments used microcolor schlieren to observe leaking LPG from microholes with pipes and determined the technical sensitivity, where the microholes were made by using electric discharge machining (E.D.M.). The experimental run conditions are different LPG leaking flow rates integrated with different microhole diameters of 1130, 176, 75, 45.6, 35.32, and 27.5 μm. The results show that present microcolor schlieren can clearly visualize microhole with ϕ27.5 μm under leaking pressure difference of 5 torr and ϕ35.32 μm with leaking pressure difference under 1 torr.