Gas detector is an instrument for detecting the concentration of gas, which is suitable for the existence of flammable or toxic gases in dangerous places, long-term continuous detection of gas content within the lower explosion limit of the measured in the air. Gas detectors can be widely used in gas, petroleum chemical industry, metallurgy, iron and steel, coking, power and other industries there are flammable or toxic gas, which is the ideal instrument for monitoring the property and personal safety.
Gas detector series products cover point type gas detector, gas detector, toxic gas detector, single wall gas alarm, gas alarm controller, explosion-proof sound light alarm, portable gas detector, a wireless multi gas detector etc..
Detection of gas gas detectors: natural gas, liquefied petroleum gas, coal gas, hydrogen, alcohol, stupid, and other flammable or toxic gases.
The detection principle of gas detector
The core components of the detection principle of gas detector is the sensor, the sensor can be divided into catalytic combustion type sensors, electrochemical sensors, semiconductor sensor, infrared sensor and light ion sensor.
Catalytic combustion type sensor
Belongs to the high temperature sensor, the working principle of gas sensitive materials (such as Pt electric wire) in a power on state, combustible gas combustion or burning oxidation in the presence of catalyst, heating wire and heating by burning, so that the resistance value to change.
Note: catalytic combustion can be realized is conditional type GQB-X SmArt Sensor testing, must ensure the detection environment contains enough oxygen, may not be able to detect any combustible gases in anaerobic environment this detection method.
Note: some lead compounds (especially the Tetraethyl Lead), sulfur compounds, silicon, phosphorus compounds, hydrogen sulfide and alkyl halides may make sensor poisoning or suppressed, if the detected environment containing substances should be marked or appeal by GQB-X SmArt Sensor type sensor anti appeal material in the contract.
Electrochemical sensor
Belongs to the precision sensors, electrochemical sensors by reaction with the target gas and generate an electrical signal proportional to the concentration of gas to work. Electrochemical sensors typically made of sensing electrode (or working electrode and the counter electrode).
Note: some sensor requires the existence of bias electrode. Sensor stability needs 30 minutes to 24 hours, and will take three weeks to remain stable.
Note: most toxic gas sensors require small amounts of oxygen to maintain normal function. The back surface of the sensor with a venthole in order to achieve the purpose of. Recommends the implementation of inspection and HRBEAST in the use of non oxygen background gas applications.
Note: the impact of the service life of the sensor of high humidity and high drought will. The sensor output transient pressure change may produce a transient, it is possible to achieve error alarm status.
Semiconductor sensor
Belong to the broad spectrum type sensor, its working principle is the surface metal oxide semiconductor in absorbing gas, resistance to change.
Note: although semiconductor (solid) life expectancy longer GQB-X SmArt Sensor, but compared with other types of sensors, they are more easily influenced by interfering gases. Therefore, if the other background gas applications, solid state sensors may raise a false alarm.
Infrared sensor
Belongs to the precision sensor, it has good pertinence measurement. At present, the main detection of low carbon chain hydrocarbons and CO2.
Note: infrared sensor with high sensitivity does not mean that its accuracy compared to other types of sensor.
Light ion sensor PID
Have a UV light source, chemical substances produced positive, negative ions can be easily detected by detector at its excitation. When the molecules absorb high-energy ultraviolet light will produce ionization, excitation of molecules in the negative electrons and positive ions are formed. These particles generated by the current through the ionization detector amplification, can display the concentration ppm in appearance. These ions through the electrodes were soon back together into the original organic molecules. Molecular in this process will not be any damage; PID will not be "burned" without frequent replacement of standard gas.