Key Operating Principle of Infrared Gas Detectors
Infrared gas detector is a commonly used gas detection device that detects gases by measuring the absorption characteristics of target gases in the infrared spectral range. Infrared gas detectors have the advantages of high precision, fast response, and good stability, and are widely used in industrial and environmental monitoring fields.
The working principle of an infrared gas detector can be summarized as follows: the infrared light source generates an infrared beam, which is detected by the transmission of the measured gas in the gas chamber, and then passes through the infrared filter to reach the infrared detector. The infrared detector converts the received infrared light signal into an electrical signal related to the concentration of the measured gas, and then amplifies and processes the signal to finally display or output the concentration value.
In infrared gas detectors, the infrared light source is a key component. The commonly used infrared light sources include thermal radiation type and semiconductor type. Thermal radiation infrared light sources typically use materials such as heating wires, emitters, or silicon carbides to emit infrared radiation through resistance heating. Semiconductor infrared light sources typically use infrared light-emitting diodes (IR LEDs) as light sources, which have the advantages of low power and long lifespan.
The function of an infrared filter is to selectively transmit infrared light while blocking light from other wavelengths. According to the characteristics and detection requirements of the tested gas, different wavelengths of infrared filters can be selected. Infrared detectors are used to receive infrared light transmitted through filters and convert the infrared light signal into an electrical signal for subsequent processing. There are two commonly used types of infrared detectors: photoconductive and thermoelectric. Photoconductive infrared detectors typically use materials such as HgCdTe to convert infrared light signals through the photoelectric effect. Thermoelectric infrared detectors achieve signal conversion by measuring the temperature changes generated by infrared light signals.
When using an infrared gas detector, the first step is to confirm the absorption characteristics of the measured gas towards infrared light. The degree of absorption of specific wavelengths of infrared light varies among different gases, so selecting appropriate filters and detectors is crucial. Secondly, it is necessary to calibrate the infrared gas detector to the corresponding measured gas. During the calibration process, it is necessary to provide a gas sample of known concentration and adjust the sensitivity and range of the instrument based on the signal generated by the sample to ensure the accuracy of the detection results.
In practical applications, infrared gas detectors are often equipped with LCD screens or digital interfaces for intuitive display of measurement results. At the same time, data can also be output to the data processing system for recording and analysis by connecting to a computer or data acquisition device. In addition, some advanced infrared gas detectors can also be equipped with alarm devices. When abnormal concentrations of gas are detected, an alarm will be issued in a timely manner to ensure safety.
