Sensor types used in coal mine gas monitoring
Date:2013-11-28 Hits:
According to the provisions of the state coal mine construction mine monitoring system, realize the dynamic monitoring of coal mine gas, carbon monoxide concentration, offer the decision basis for coal mine safety management. The number one killer of accident in the coal mine gas accident, prevent gas accidents, the good gas monitoring can truly be the accident nipped in the bud.
Gas gas monitoring performance mainly depends on the sensor, the sensor of a coal mine gas monitoring:
1, contact combustion type gas sensor
Catalytic combustion gas sensor using the combustion characteristics, to gas content detection in air, flammable gas (H2, CO, CH4 etc.) contact with oxygen in the air, the oxidation reaction occurs, generating heat of reaction (flameless combustion heat, making contact) as a platinum wire temperature sensitive material. The resistance value increases. Therefore, as long as the determination of platinum wire resistance change as the sensitive parts of the value, concentration can be detection of combustible gas in air.
2, semiconductor gas sensor
Semiconductor gas sensor with semiconductor surface adsorbed gas conductivity changes made, most semiconductor material is used by SnO2, ZnO, Fe2O3 etc.. Electrical conductivity with no attached gas change, such as fresh air through the detector current is very stable, but when the gas such as methane, propane and other contact to the detector surface, due to rising gas concentration detector, impedance immediately reduced, current changes, it only wants to determine the current value, you can check the concentration of gas. At present, this sensor is more popular.
3, thermal resistance of gas sensor
The heat conduction type gas detection resistance component is the high reliability of the gas sensor. Thermal gas detector has the following problems: must be long-term changes in resistance assembly to be overlooked, the gas sensing components and compensation with heat loss component must not affect the practicability; device at normal temperature and pressure resistance type gas detector coupled with heat conduction, because the higher rate of water vapor effect of this system, so susceptible to humidity, although can be detected non combustible gas, but not easy to gas determination of thermal conduction, the application of this sensor in coal mine is not much.
Gas monitoring is an effective way to curb the gas accidents, select the appropriate gas monitoring system, the gas monitoring on the focus of the work of coal mine gas accident, will effectively reduce the.
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