PID gas monitor technology principle

What is PID gas monitor?

PID gas monitor is an instrument that analyzes the gas concentration by using a built-in PID sensor and an ultraviolet (UV) light source. Working principle: PID uses a ultraviolet lamp (UV) light source will be organic matter into a detector can be detected by the positive and negative ions (ionization), first of all in the ionization of electrons and positively charged ions under the action of the electric field, the formation of a weak electric current, and then PID gas detector through the detection of the current strength to reflect the content of the substance, and finally the detector to measure the ionization of the electric charge of the gas and will be converted to the current signal, the current is amplified and passed to the gas detector. Finally, the detector measures the charge of the ionized gas and converts it into a current signal, which is amplified and converted by the corresponding algorithm to derive the concentration and composition of the gas.

FS03101 (4)
PID gas sensor

PID gas monitor advantages and features

1.PID gas monitor is applicable to a wide range of detection, at present basically can be applied to detect VOC volatile organic compounds, can also be applied to emergency trace gas leakage detection. (Note: limited by the PID lamp life and susceptible to humidity characteristics, not recommended for gas online monitoring system applications)

2.PID gas monitor high precision, support can detect ppb level (parts per billion) of VOC volatile organic gases, in addition to the traditional PID photoionization gas detector can detect ppm level (parts per million) of organic gases, accuracy over other infrared, electrochemical, catalytic combustion and other principles.

3.PID gas detector on the detection of gas non-destructive, good stability, the general gas detector in the gas inhalation will be ionized, and gas molecules formed by ions in the discharge and formed the original gas molecules, the original gas molecules without damage.

4.PID gas detector response speed, long life. Under normal working condition, PID gas detector can respond almost in real time and can be tested continuously. In addition, usually a UV lamp life in thousands of hours, conventional conventional PID gas detector design life up to 5 years or more.


Disadvantages: PID gas detector is more expensive, if the budget is not enough friends, then recommend that you can consider choosing the traditional other electrochemical, infrared, semiconductor and other principles of gas detector.

Electrochemical gas sensor

What gases is PID gas monitor suitable for?

PID gas monitor is suitable for detecting VOC, TVOC, benzene, toluene, ammonia, carbon disulfide, trimethylamine, olefins, aromatic hydrocarbons, acetone, acrylonitrile, acetic acid, ethyl acetate, ethyl ether, methyl mercaptan, methyl mercaptan, styrene, vinyl chloride, and other volatile gases. However, the range of VOCs can be quite complex, and the types of gases can reach up to one million species, so it is important to verify the range of gases to be detected before using PID gas monitor. Verify the detection range before using the PID gas detector.

Note: not all gases can be detected with PID gas detector, which is mainly related to the PID sensor within the UV lamp can be ionized potential, i.e., higher than the ionization potential of the gas can not be ionized split. For example, the gas can not be detected are: nitrogen, oxygen, carbon dioxide, carbon monoxide, sulfur dioxide, ozone, methane, ethane, propane, freon and so on. In addition, PID gas detector is not suitable for detecting radioactive gases, highly toxic gases, flammable gases (most of them do not react to LEL flammable gases).