Ultrafast leak detection of propane/butane propellants by laser spectroscopy


Gas propellants in aerosol cans are typically highly flammable and if released they pose fire and explosion hazards. The international transport regulations for dangerous goods require that every single can is tested for leak tightness before leaving the factory. However, the standard method of water bath testing is bulky, costly, and energy demanding (~ 65 kW).

Addressing the industrial needs for a more compact, environmental friendly and reliable alternative testing method, we have developed in close collaboration with our industrial partner (Wilco, AG) a Mid-IR optical analyzer, which uses a broadband 3.3 µm Fabry-Perot quantum cascade laser. The instrument provides for excellent sensitivity, selectivity and speed, with the additional advantage of minimal energy consumption. Low traces of propane (~10 ppm) can reliably be detected within a time frame of only 10 ms. The realized industrial demonstrator for leak testing achieved detection speeds up to 500 aerosol cans per minute at a leaking rate of 1.2*10-4 L/min, which is in compliance with EU and international directives