STUDY OF THERMOCATALYTIC COMBUSTIBLE GAS SENSORS UNDER WATER INGRESS INTO THEIR GAS DIFFUSION FILTERS

Abstract

Purpose. To investigate the impact of accidental water ingress into the metal-ceramic gas diffusion filters of thermocatalytic sensors on the performance of explosion hazard monitoring devices.

Methods. The study employs experimental research methods under laboratory conditions using serial thermocatalytic pellistor-type sensors with a non-selective platinum-palladium catalyst. The results are assessed and generalized.

Results. The conducted research allowed us to evaluate the effect of water ingress into thermocatalytic sensors with metal-ceramic filter elements on the performance of explosion hazard monitoring devices. It was found that even after multiple instances of water ingress using distilled water, the characteristics of the thermocatalytic sensors remained unchanged after the filter elements dried. When exposed to purified mineralized water, repeated water ingress led to zero drift in gas analyzers and, in some cases, a slight decrease in sensitivity. In contrast, exposure to unpurified mineralized water resulted in zero drift across all analyzers and a reduction in sensitivity.

Novelty. It was established that repeated water ingress into the metal-ceramic gas diffusion filters of thermocatalytic sensors using unpurified highly mineralized water leads to zero drift of gas analyzers toward positive values and a reduction in sensitivity. This effect is attributed to the accumulation of salt deposits on the inner surface of the filters and an increase in the gas diffusion resistance of the filter.

Practical significance. The findings establish conditions under which it is necessary to check and calibrate explosion hazard monitoring devices based on the thermocatalytic method when operating in coal mines and early hazard detection systems at oil and gas facilities.