In the last two issues, we share the introduction of electrochemical and infrared sensors. Now we introduce the PID photo-ion sensor.

​Photo-ion gas sensor is also called PID The photo-ion gas sensor based on the principle of photoionization gas,and has the characteristics of small volume, high brightness, plug and play, intrinsically safe, etc. Optical ion gas sensors have unparalleled advantages in the detection of trace gases such as organic volatiles ( VOCs ). Because the packaging mode is fully compatible with City Technology-4P packaging. As a result, it can be easily integrated into a handheld / desktop / stationary gas detection system.

PID sensor Advantages:

The PID sensor is composed of ultraviolet lamp light source and ion chamber. There are positive and negative electrodes in the ion chamber, which form the electric field. Under ultraviolet light irradiation, the gas to be measured ionizes to form positive and negative ions, and an electric current is formed between the electrodes, and then the output signal is amplified. PID has the advantages of high sensitivity, no poisoning problem, safety and reliability, and can detect more than 400 kinds of volatile organic gases.

Working principle:

The PID sensor is composed of ultraviolet lamp light source and ion chamber.  

There are positive and negative electrodes in the ion chamber, which form the electric field. / Under ultraviolet light irradiation, the gas to be measured ionizes to form positive and negative ions, and an electric current is formed between the electrodes, and then the output signal is amplified.

The PID is the most convenient and sensitive method to detect organic volatile ( VOCs ）.Has incomparable advantages over other types of sensors,especially for very low concentrations of gas leakage. In summary, the photoion-gas sensor ( PID ） is mainly used for the detection of organic volatile compounds ( VOCs ）, which include:

1 、1.Aromatics: benzene, xylene, naphthalene, etc.;  

2 、2.Saturated and unsaturated hydrocarbons: octane, ethylene, cyclohexane, etc.;  

3 、3.Ketones, aldehydes, ethers: acetone, Propionaldehyde, methoxymethane, etc.;  

4 、4.Halogenated hydrocarbons, sulfur hydrocarbons, alcohols,esters, hydrazine, etc.;

5 、In addition, detectable inorganic substances include arsenic and ammonia.

The following substances are not detectable with PID sensors:  

1 、Air : N2 ， O2 ， CO2 and water

2 、Toxic and harmful gases: CO ， HCN ， SO2  

3 、 Combustible gas: CH4 、 C2H6

4 、Acids gas: HCL ， HF ， HNO3

5 、Other: freon, O3