The working principle of fixed cl2 gas detector is mainly based on electrochemical or infrared absorption technology. The core is to convert chlorine concentration into a measurable signal through chemical reaction or optical properties. The details are as follows:
1. Electrochemical principle: Chlorine enters the sensor through the breathable membrane and undergoes redox reaction with the electrolyte between the working electrode and the reference electrode; the generated current is linearly related to the chlorine concentration. The microcurrent is processed by the amplification circuit, converted into a voltage signal, and then outputs a digital concentration value through analog-to-digital conversion.
(1).Core components
Breathable membrane: Selectively permeates chlorine molecules and blocks dust/water vapor interference
Working electrode: Catalyzes chlorine reduction reaction (gold/platinum material)
Counter electrode: Maintains charge balance (commonly used lead or carbon materials)
Electrolyte: Provides ion-conducting medium (liquid or solid polymer)
Signal processor: Amplifies microcurrent and linearizes it into concentration readings
(2).Performance characteristics
①. Sensitivity: Detection limit as low as 0.001ppm (parts per million), response time ≤30 seconds.
②. Selectivity: The special electrode design can suppress the influence of interfering gases such as hydrogen sulfide and sulfur dioxide.
③. Stability: The constant temperature compensation circuit reduces the error caused by environmental temperature and humidity fluctuations.
④. Lifespan: Typical service life is 2-3 years (under normal working conditions).
2. Infrared absorption principle: Based on infrared absorption spectroscopy technology, chlorine (Cl₂) molecules have a specific infrared absorption band. When the light emitted by the infrared light source passes through the gas sample containing chlorine, the chlorine molecule will absorb infrared light of a specific wavelength, resulting in the attenuation of the transmitted light intensity. The attenuation degree of the transmitted light intensity is exponentially related to the chlorine concentration, thereby directly calculating the concentration.Signal detection process as below:
(1).Infrared light source: emits continuous broadband infrared light (commonly used tungsten filament lamp, silicon carbon rod).
(2).Filter system: filter out the characteristic absorption wavelength of chlorine (such as a specific mid-infrared band) through interference filter or monochromator.
(3).Gas chamber sampling: The gas to be tested enters the gas chamber and absorbs infrared energy of the target wavelength.
(4).Detector conversion: The remaining infrared light is received by thermopile, pyroelectric and other detectors and converted into electrical signals.
(5).Concentration calculation: The microprocessor calculates the chlorine concentration value by measuring the light intensity attenuation of the measuring device.
(6).Advantage comparison: The electrochemical principle has fast response and high sensitivity, which is suitable for real-time monitoring; the infrared principle has strong anti-interference and is suitable for complex environments.