What is the difference between PID and FID principles of portable voc gas detector
VOC usually refers to the kind of volatile organic compounds that cause harm. There are many types and a wide range of sources. It is one of the pollution hazards of modern life and production. The portable voc gas detector can detect the concentration range of voc to determine the size of the hazard. Among them, the portable voc gas detector with PID principle and FID principle is more commonly used. What is the difference between the two?
1. The principle of detection is different
The portable voc gas detector based on the PID principle uses ultraviolet light to ionize the sample gas to monitor the concentration of voc when detecting the sample gas. After the sample gas is discharged, the sample gas can still be analyzed again. When the online monitor detects the sample gas, it uses a hydrogen flame to ionize the sample gas. After the burned sample gas is discharged, the composition and concentration of voc gas have changed, and secondary analysis is not possible.
Two, installation and use are different
In terms of installation and use, the voc gas detector using PID is small and portable, easy to install, and low in cost. However, the voc gas detector based on the FID principle requires a hydrogen bottle or an online hydrogen generator, so the installation difficulty and technical requirements are higher, and the cost is higher than that of the PID principle.
3. Different types of gases detected
The voc detected by the PID principle includes saturated and unsaturated hydrocarbons, aromatics, amines, halogenated hydrocarbons, thiohydrocarbons, alcohols, lipids, and hydrazine gases; the FID principle is widely used for volatile hydrocarbons and Detection of many carbon compounds.
Fourth, the scope of monitoring is different
The monitoring range of the FID principle is 1-50000ppm, while the monitoring range of the PID principle is 1-4000ppm or 0.1-10000pmm; when the concentration of voc is higher than 10000ppm, the FID linearity is better. Therefore, when users choose the principle of voc gas detector, they need to decide according to the on-site voc concentration.
