DEVICE FOR CONTROLLING CONCENTRATION OF METHANE IN UNDERGROUND MINES

摘要

FIELD: mining.;SUBSTANCE: present invention pertains to safety provisions, used in underground mines, and particularly to sensors for monitoring concentration of explosive gas, for example, methane. A system for indicating methane concentration, together with a power supply, is put into a sealed case, to one of the walls of which is sealed a case of an optical cell with air access holes. Inside the case there are two mirrors, lying parallel to each other and to the common wall of the cases. A light-emitting diode is fitted at one edge of the common wall of the cases, and a photodiode is fitted on the other edge. The output of the photodiode is connected to the input of the generator of electrical pulses. The output of the generator is connected to the input of a frequency detector, whose output is connected to the input of an amplifier, with a calibration resistor. The output of the amplifier is connected to the methane concentration indicator and a null device, with a resistor. The output of the null device is connected to the input of the signal generator with an alarm device.;EFFECT: increased accuracy of determining concentration of methane in the atmosphere and simplification of the design of the device.;2 cl, 2 dwg