Professional Knowledge Guidance on Gas Detectors
How much do we know about gas detection and what do we know about gas detection instruments. Even if you don't know now, it's okay. Here, the editor will introduce professional knowledge guidance about gas detectors. Please take a look.
Gas detectors mainly use 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. Also known as gas alarm, it is an instrument tool for detecting gas leakage concentration, mainly referring to portable/handheld gas detectors. 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, regardless of whether it uses 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 generally consistent detection principles.
There are approximately the following types of gas sensors currently popular in the market:
1. Semiconductor gas sensor
It is manufactured using the principle that the conductivity of some metal oxide semiconductor materials changes with the composition of the ambient gas at a certain temperature. For example, an alcohol sensor is prepared based on the principle that when tin dioxide encounters alcohol gas at high temperatures, its resistance will sharply decrease. Semiconductor gas sensors can be effectively used for detecting many gases. 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.
Disadvantages: 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 places that require accurate measurement.
At present, the main suppliers of this type of sensor are Japan (inventor), followed by China. Recently, South Korea has joined the market, and other countries such as the United States have also made considerable efforts in this area, but it has not yet entered the mainstream! China has invested as much manpower and time in this field as Japan, but due to years of national policy guidance and social information blockage, the performance and quality of semiconductor gas sensors popular in the market in China are far inferior to Japanese products. It is believed that with the progress of the market and the further rise of private capital, China's semiconductor gas sensors will soon reach and surpass Japan's level
