Combustible harmful gas detector capable of eliminating temperature drift

Abstract

The invention provides a combustible harmful gas detector capable of eliminating a temperature drift. The detector comprises a housing, a temperature feedback control circuit, a gas sensitive sensor and a sampling resistor, wherein the temperature feedback control circuit is connected with the heating wire RH of the sensitive sensor; and the sampling resistor is connected in series with a sensitive resistor RS of the gas sensitive sensor. The combustible harmful gas detector has the beneficial effects that by the temperature feedback control circuit, sensor heating voltage can be automatically adjusted along with the change of environmental temperature, so as to guarantee a stable working temperature of a sensitive material of the sensor and eliminate influence on the precision of the sensor due to the temperature drift. In different external environments, the temperature drift characteristic of a conventional metal oxide semiconductor gas sensitive sensor can reduce the detection precision. The combustible harmful gas detector integrated with the temperature feedback control circuit can well solve the problem; the reliability of a detection result of the detector is much higher than that of a detection device without temperature compensation, and the detection error is reduced from original -40 percent to +70 percent to + / - 10.

Description

technical field [0001] The invention belongs to the technical field of gas detection, and in particular relates to a flammable and harmful gas detector capable of eliminating temperature drift. Background technique [0002] Metal oxide semiconductor gas sensors are widely used in flammable and harmful gas detection systems. Its working principle is as follows: figure 1 Shown: The heating wire is equivalent to the heating resistance R H , the sensitive material is equivalent to the sensitive resistor R S , R L is the sampling resistor. Apply a voltage V to the sensor heating circuit H , so that the sensor sensitive material works at a steady state of about 300°C. When the detection gas touches the semiconductor surface and is adsorbed, the resistance R S resistance changes, by detecting R L voltage across The gas can be detected indirectly. [0003] Such sensors are known to be highly susceptible to output drift due to ambient temperature. When the temperature is l...

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Problems solved by technology

[0006] The problem to be solved is to eliminate the temperature drift of the metal oxide semiconductor gas sensor. The purpose of the present invention is to provide a flammable and harmful gas detector that eliminates the temperature drift. Through a temperature feedback control circuit, when the ambient temperature changes, the corresponding change R H The heating voltage keeps the working temperature of the sensitive material stable and solves the problem of R from the source S The problem of being easily affected by the ambient temperature improves the compensation accuracy

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