Working principle of infrared gas detector
Infrared gas detector is a portable gas detector with high precision, high resolution, long service life and easy maintenance, which adopts special infrared gas analysis technology. This kind of infrared gas detection is widely used in many industries, and the detection of flammable, explosive, toxic and harmful gas concentration has always been of great significance to safety production.
Among them, infrared absorption spectrum is not only used to measure gas concentration, but also widely used to identify the structures of different molecules from characteristic absorption. And has high sensitivity and quick response, can continuously indicate on line, and can also form an adjusting system. The detection part of the infrared gas detector commonly used in industry consists of two parallel optical systems with the same structure. One is the measuring room and the other is the reference room. The two chambers simultaneously or alternately open and close the light path through the light cutting plate in a certain period.
After the measured gas is introduced into the measuring chamber, the light with the specific wavelength of the measured gas is absorbed, so that the luminous flux entering the infrared receiving gas chamber through the optical path of the measuring chamber is reduced. The higher the gas concentration, the less the luminous flux entering the infrared receiving gas chamber; The luminous flux passing through the reference chamber is constant, and so is the luminous flux entering the infrared receiving gas chamber.
Therefore, the higher the concentration of the measured gas, the greater the difference in luminous flux between the measuring chamber and the reference chamber. This luminous flux difference is projected to the infrared receiving gas chamber with the amplitude of a certain period of vibration.
The receiving gas chamber is divided into two halves by a metal film with a thickness of several microns, and the measured component gas with a relatively high concentration is sealed in the chamber, so that the injected infrared ray can be completely absorbed within the absorption wavelength range, so that the pulsating luminous flux can be changed into a periodic change of temperature, and then the change of temperature can be converted into a change of pressure according to the gas equation, and then it is detected by a capacitive sensor, and the measured gas concentration is indicated after amplification.
The infrared gas detector is suitable for detecting all kinds of flammable, explosive and carbon dioxide gases, and has the remarkable characteristics of high precision, good selectivity, high reliability, no poisoning, no dependence on oxygen, less environmental interference, long service life, etc., occupying a wider industry market and gradually becoming the mainstream of the market in the future.
