INFRARED SENSOR FOR METHANE CONTENT IN AIR Russian patent published in 2025 - IPC G01N21/3504 

FIELD: measuring.

SUBSTANCE: invention relates to measurement equipment, in particular to infrared sensors used in gas analysers, and is intended to determine places of methane leakage from a gas pipeline using an automotive laboratory moving along the route of the gas pipeline. Infrared sensor of methane content in air contains a unit for control, reception and processing of data, electrically connected to it laser radiation unit, an analytical cell equipped with a fibre-optic collimator connected by means of an optical fibre to a laser radiation unit and an optical signal detector electrically connected to the control unit. Input to the analytical cell is connected to the atmospheric air supply device, and the output from it is connected to the atmosphere. Laser radiation unit comprises a diode laser with distributed feedback with radiation output to a single-mode optical fibre connected to a fibre-optic collimator, as well as a Peltier thermocouple thermally connected to the diode laser with the possibility of maintaining stability of the laser diode radiation in a given wavelength range. Thermal element is equipped with a built-in temperature sensor which determines the heating temperature of the laser diode, as well as a built-in photodiode, through which feedback is carried out with the diode laser for calibrating the methane sensor. Body of the analytical cell is heat-conducting and is equipped with an ambient temperature sensor mounted on it. Detector is also fixed on the heat-conducting housing of the analytical cuvette and thermally connected to the ambient temperature sensor. Inside the cuvette there is a multipass mirror system with six mirrors mounted on the walls of the cuvette body, with two mirrors optically connected to a laser radiation source and an analytical signal detector, which enables to provide an optical path of laser radiation of at least 3 m.

EFFECT: high sensitivity to low concentrations of methane in air at significant volumes of an atmospheric air sample at various ambient temperature conditions.

1 cl, 4 dwg, 2 tbl