Thermal gas sensor

Thermal gas sensor are mainly thermal conductivity and thermal chemical formula of two categories. Thermal conductivity is the use of the thermal conductivity of the gas , through which the change in resistance of thermistor to measure the concentration of one or several gas components , and its application in the industry for several decades already , the type of meter more, to analyze gases are more widely used ( such as H2, CO2, SO2, NH3, Ar , etc. ) . Thermal chemical formula is based on the gas being analyzed chemical reaction heat effect , which widely used is gas, the oxidation reaction ( i.e. combustion ) , typically a catalytic combustion type Engine Coolant Temp Sensor, the key member is coated with a combustion catalyst Wheatstone bridge , the main for the detection of combustible gases, such as gas stations, gas plant is used to analyze the air CO, H2, C2H2 and other combustible gases , coal mine used to analyze the content of CH4 in the trenches , oil exploration vessels leak methane content of the scene , fuel and chemical raw materials storage warehouse or workshop materials analysis of oil vapor in the air , such as alcohol, ether vapor . U.S. RAE Systems produced FGM-3100 catalytic combustion of combustible gas detector , the sampling method is diffused , the detection accuracy of ± 2% of full scale , response time <15s. Catalytic combustion type gas Crankshaft Sensors The main advantage is that the response of all combustible gases broad spectrum, the ambient temperature , humidity insensitive to near-linear output signal , and its simple structure and low cost. But its main deficiency is low accuracy , high working temperature ( internal temperature up to 700 ~ 800 ℃), current consumption large , vulnerable sulfide, halogen compounds such as poisoning and other adverse effects .