Semiconductor type It is made by using some metal oxide semiconductor materials to change the conductivity with changes in the composition of the ambient gas at a certain temperature. For example, an alcohol sensor is prepared by the principle that the resistance of the tin dioxide is drastically reduced when it encounters alcohol gas at a high temperature. advantage The semiconductor gas sensor can be effectively used for the detection of many gases such as methane, ethane, propane, butane, alcohol, formaldehyde, carbon monoxide, carbon dioxide, ethylene, acetylene, vinyl chloride, styrene, acrylic acid and the like. In particular, such sensors are inexpensive and suitable for the needs of civil gas detection. The following semiconductor gas sensors have been successful: methane (natural gas, biogas), alcohol, carbon monoxide (city gas), hydrogen sulfide, ammonia (including amines, terpenoids). High quality sensors meet the needs of industrial inspection. Disadvantage The stability is poor and is greatly affected by the environment; in particular, the selectivity of each sensor is not unique, and the output parameters cannot be determined. Therefore, it should not be used in places where accurate measurement is required. Catalytic combustion The sensor is prepared on the surface of the platinum resistance to form a high temperature resistant catalyst layer. At a certain temperature, the flammable gas is catalytically burned on the surface thereof, and the combustion is the temperature rise of the platinum resistance, the resistance changes, and the change value is the flammable gas concentration. function. advantage Catalytic combustion gas sensors selectively detect flammable gases: the sensor does not respond to any failure to burn. The catalytic combustion gas sensor is accurate in measurement, fast in response, and long in life. The output of the sensor is directly related to the explosion hazard of the environment and is a dominant type of sensor in the field of safety detection. Disadvantage In the range of flammable gases, there is no selectivity. Working in a dark fire, there is a danger of igniting an explosion. Most of the elemental organic vapors are toxic to the sensor. Thermal conductivity pool Each gas has its own specific thermal conductivity. When the thermal conductivity of two or more gases is different, the thermal conductivity element can be used to distinguish the content of one of the components. Such sensors have been used for the detection of hydrogen, the detection of carbon dioxide, and the detection of high concentrations of methane. This gas sensor has a narrow application range and many limiting factors. The gas detector is an instrumentation tool for gas leakage concentration detection, mainly referring to a portable/handheld gas detector. Gas sensors are mainly used to detect the types of gases present in the environment, and gas sensors are sensors for detecting the composition and content of gases. Coffee Table,Living Room Table,Round Coffee Table,Center Table Foshan Poesy Furniture Co., LTD. , https://www.poesyfurniture.com
December 20, 2022