What is the difference between the PID and FID principles of portable VOC gas detectors?
VOC usually refers to the type of volatile organic compounds that cause harm, with a wide range of types and sources, and is one of the pollution hazards in modern life and production. The portable VOC gas detector can detect the concentration range of VOC to determine the magnitude of the hazard. What are the differences between portable VOC gas detectors based on PID principle and FID principle?
1, The principle of detection is different
The portable VOC gas detector based on PID principle uses ultraviolet light to ionize the sample gas to monitor the concentration of VOC. After the sample gas is discharged, secondary analysis can still be performed on the sample gas. However, the VOC online monitor based on FID principle uses hydrogen flame to ionize the sample gas. After the combustion of the sample gas is discharged, the VOC gas composition and concentration change, and secondary analysis cannot be performed.
2, Installation and use are different
In terms of installation and use, the VOC gas detector using PID is compact, easy to carry, simple to install, and cost-effective. The VOC gas detector based on the FID principle requires hydrogen cylinders or online hydrogen generators, making it more difficult and technically demanding to install, and also more expensive than the PID principle.
3, Different types of gases are detected
The VOCs detected by PID principle include saturated and unsaturated hydrocarbons, aromatic hydrocarbons, amines, halogenated hydrocarbons, thiohydrocarbons, alcohols, lipids, and hydrazine gases; The FID principle is widely used for the detection of volatile hydrocarbons and many carbon containing compounds.
4, The scope of monitoring varies
The monitoring range of FID principle is 1-50000ppm, while the monitoring range of PID principle is 1-4000ppm or 0.1-10000pmm; When the concentration of VOC is higher than 10000ppm, FID linearity is better. So when users choose the principle of VOC gas detector, they need to decide based on the on-site VOC concentration.
