Whole-range combustible gas detector

Abstract

The invention discloses a whole-range combustible gas detector. In a detection and control circuit of the whole-range combustible gas detector, a measuring bridge consists of a sensing element RH, a compensating element RB and resistors R1 and R2, another measuring bridge consists of a compensating element RB and resistors R2, R3 and R4, the two measuring bridges are respectively controlled by switch pipes to be switched on of off, and the midpoints of two arms of the measuring bridges are accessed to an amplifier circuit for an instrument; when the concentration of a combustible gas is lower than 100 percent LEL (Lower Explosive Limit), the front measuring bridge works; and when the concentration of the combustible gas is higher than 100 percent LEL, the rear measuring bridge works. The invention overcomes the weakness that a conventional catalytic sensor can only measure the combustible gas with the concentration lower than explosive limit concentration, realizes double functions that a pair of sensors can accurately measure high-concentration and low-concentration combustible gases and fundamentally solves the problems of short service life and poor contact of the traditional membrane switch or the traditional microswitch by an induction key technology.

Description

1. Technical field [0001] The invention belongs to measuring and detecting instruments, in particular to a combustible gas detecting instrument. 2. Background technology [0002] The main problems of currently used thermal catalytic combustion combustible gas detectors are large sensor drift, regular maintenance, short maintenance cycle, complex maintenance methods, high cost, and poor anti-interference ability. Moreover, the existing ordinary full-range combustible gas detector (mainly used for methane detection) adopts the detection mechanism of the combination of the carrier catalytic element and the binary thermal conductivity element, and the carrier catalytic element is still used for low concentration detection; while the high concentration detection uses binary Elemental heat conduction element, the circuit structure is more complex, the high concentration and low concentration ranges are interrupted and jump, and the range is discontinuous. 3. Contents of the inve...

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Problems solved by technology

[0002] The main problems of currently used thermal catalytic combustion combustible gas detectors are large sensor drift, regular maintenance, short maintenance cycle, complex maintenance methods, high cost, and poor anti-interference ability

Moreover, the existing ordinary full-range combustible gas detector (mainly used for methane detection) adopts the detection mechanism of the combination of the carrier catalytic element and the binary thermal conductivity element, and the carrier catalytic element is still used for low concentration detection; while the high concentration detection uses binary No heat conduction element, the circuit structure is more complicated, the high concentration and low concentration ranges are interrupted and jump, and the range is discontinuous

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