ALARM SYSTEM SIGNALLING MAXIMAL CONCENTRATION OF METHANE IN ATMOSPHERE Russian patent published in 2011 - IPC G08B17/117 G08B25/00 

FIELD: machine building.

SUBSTANCE: system consists of warning device and reader, of identification marks, or re-transmitters and of control room. The warning device consists of bridge measuring circuit, of an analogue switchboard, of an amplifier of direct current, of an accumulator battery, of an arithmetic and logical unit, of an analogue-digital converter, of a digital-analogue converter, of a memory device, of an indicator of a threshold level and of a key. The reader includes a master generator, a duplexer, a receiving-transmitting aerial, the first and second power amplifiers, a phase detector, a line of delay, a generator of pseudo-random sequence, a summator, a multiplier, a narrow-band filter and a phase manipulator. Each identification mark contains piezo-crystal, a micro-band aerial, electrodes, bus bars, and a set of reflectors. The control room contains a receiving aerial, an amplifier of high frequency, a search unit, a heterodyne, a mixer, an amplifier of intermediate frequency, a phase doubler, analysers and spectres, a comparison unit, a threshold unit, a delay line of key, a narrow-band filter and a divider of phase in two, a phase detector and a recording unit.

EFFECT: operative transmitting of information to control room for increased safety of miners.

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