TVOC gas detector measurement method types
The measurement methods of TVOC gas detectors mainly include photoionization detection, electrochemical detection, infrared absorption, optical absorption, and gas chromatography.
Photoionization detection method (PID detection method): This method uses a vacuum ultraviolet lamp with specific ionization energy to generate ultraviolet light, which bombards gas molecules entering the ionization chamber through a filter membrane, ionizing and breaking down organic molecules in the gas into positively charged ions and negatively charged electrons. Under the electric field of the electrode, ions and electrons collide with the electrode plate, forming a detectable weak ion current. After being amplified by a high-sensitivity microcurrent amplifier, these current signals are collected and converted into digital signals for display as gas concentration values.
Electrochemical detection method: This method is based on the principle of chemical reaction, and uses electrodes to react TVOC in the air with reagents, generating electrical signals to measure TVOC concentration. This method has the advantages of high sensitivity, fast response speed, and simple operation, but it requires the use of chemical reagents and has a certain degree of pollution to the environment.
Infrared absorption method: This method calculates the TVOC concentration by detecting the degree of absorption of specific wavelengths of infrared light by TVOC molecules in the air. It does not require chemical reagents, is easy to operate, and has a fast response speed, but has certain limitations on the measurement range of TVOC concentration.
Optical absorption method: This method calculates the TVOC concentration by detecting the degree of scattering of specific wavelengths of light by TVOC molecules in the air. This method has a wide measurement range and fast response speed for TVOC concentration, but it requires the use of optical components and has a certain degree of environmental pollution.
Gas chromatography: This method separates TVOC in the air from the gas chromatography column and measures the concentration of TVOC in the column. This method has the characteristics of high measurement accuracy and fast response, but it requires the use of equipment such as gas chromatography columns and detectors, which is costly.
