Because of the different detection gases, the sensors used are not the same, and even the same gas concentration can be detected by gas sensors of different principles, or the same gas in different environments, must be detected by gas sensors of different detection principles to more accurately detect the gas concentration. Each detection principle
The advantages and disadvantages of gas sensors are different, and the key to determine their advantages and disadvantages lies in the characteristics of the gas sensor itself. Infrared gas sensors and catalytic combustion sensors are used to detect combustible gases in the gas detector industry. The difference between the two is that catalytic combustion is widely used because it can detect all kinds of combustible gases, while infrared sensors can only be used to detect alkanes, therefore, in petrochemical factories, natural gas pipelines, coal mines and other occasions where alkanes may appear, it is more suitable to use infrared gas sensors to detect gas detectors.
The output electrical signal of the catalytic combustion gas sensor is proportional to the concentration of the measured combustible gas, which has the advantages of small influence by temperature and humidity, low price and high sensitivity. Its disadvantage is that it can only work in an environment containing low concentrations of combustible gases, it is easy to damage in high concentrations of combustible gases, and it is susceptible to poisoning by gases such as sulfide, and its detection sensitivity will constantly change, requiring frequent zero calibration with standard gas.
When detecting alkanes combustible gases, the use of infrared gas sensors has very large advantages compared to catalytic combustion gas sensors:
Infrared gas sensor detection principle is the use of physical optics for gas concentration detection, so unlike the catalytic combustion sensor is limited by the concentration of the measured gas, the measurement range is relatively larger, not only can detect low concentration of alkanes gas, but also can detect high concentration of alkanes combustible gas, improve the applicability of gas detector. It is more suitable for working in coal mines, natural gas pipelines, chemical plants and other environments where the concentration of combustible gases varies widely.
The infrared gas sensor uses a reference optical path to compensate the drift of the light source, and adopts temperature compensation technology, so that the sensitivity of the catalytic combustion sensor is constantly changing due to catalyst poisoning and other shortcomings. The sensitivity of the infrared gas sensor can be maintained for a long time, thus reducing the frequency of correction and maintenance, especially in the need for long-term unmanned or difficult maintenance occasions.
The infrared gas sensor does not need to have no requirement for the oxygen concentration of the tested environment, and can work normally in an anoxic environment, such as a gas pipeline where the oxygen content is too low to be suitable for catalytic combustion sensors.
The infrared gas sensor is a direct measurement, the response speed is faster than the catalytic combustion sensor, and the work efficiency is higher.
The infrared gas sensor has stronger anti-interference, will not be affected by gases such as sulfide and cause poisoning, and the service life of the infrared gas sensor depends on the life of the light source, and the service life is longer.
At present, the gas detector using infrared sensor has been widely used in the petrochemical, coal and other industries of alkane gas detection. Through technological innovation and improvement, the cost and failure rate of infrared sensors are also being reduced, and its prospects will be better and better.