Maintaining and extending sensor life
Gas detector is an instrument tool for detecting gas leakage concentration, which includes portable gas detectors, handheld gas detectors, fixed gas detectors, online gas detectors, etc. Mainly using gas sensors to detect the types of gases present in the environment, gas sensors are sensors used to detect the composition and content of gases.
It is generally believed that the definition of gas sensors is based on the classification of detection targets, which means that any sensor used to detect gas composition and concentration is called a gas sensor, whether it is using physical or chemical methods. For example, sensors that detect gas flow are not considered gas sensors, but thermal conductivity gas analyzers are important gas sensors, although they sometimes use roughly the same detection principle.
Half it is manufactured using the principle that the conductivity of some metal oxide semiconductor materials changes with the composition of environmental gases at a certain temperature. For example, an alcohol sensor is prepared using the principle that when tin dioxide encounters alcohol gas at high temperatures, its resistance will sharply decrease.
advantage
Semiconductor gas sensors can be effectively used for detecting many gases such as methane, ethane, propane, butane, alcohol, formaldehyde, carbon monoxide, carbon dioxide, ethylene, acetylene, vinyl chloride, styrene, acrylic acid, etc. Especially, this type of sensor is low-cost and suitable for the needs of civilian gas detection. The following semiconductor gas sensors are successful: methane (natural gas, biogas), alcohol, carbon monoxide (city gas), hydrogen sulfide, ammonia (including amines and hydrazine). High quality sensors can meet the needs of industrial testing.
shortcoming
Poor stability and significant environmental impact; Especially, the selectivity of each sensor is not unique, and the output parameters cannot be determined. Therefore, it is not suitable for use in places where measurement accuracy is required.
This type of sensor is a high-temperature resistant catalyst layer prepared on the surface of a platinum resistor. At a certain temperature, combustible gases catalyze combustion on its surface. Combustion is a function of the concentration of combustible gases as the platinum resistor temperature increases and the resistance changes.
Thermal conductivity pool type
Each gas has its own specific thermal conductivity. When there is a significant difference in thermal conductivity between two or more gases, a thermal conductivity element can be used to distinguish the content of one component. This type of sensor has been widely used for detecting hydrogen, carbon dioxide, and high concentration methane.
This type of gas sensor has a narrow application range and many limiting factors.
