1. In short, the detection of harmful substances has two purposes: explosion detection and hydrogen flow meter detection. It is said that explosion detection is to detect the content of natural gas in the risk site, which is beyond the standard alarm, so as to prevent the occurrence of explosion events; poison detection is to detect the content of harmful gas in the risk site, which is beyond the standard alarm, so as to prevent workers from poisoning. The scope of explosion detection is 0-100% LEL, and the scope of poison detection is 0-dozens (or hundreds) ppm, which is quite different. Establish the test destination and select the instrument type

There are three kinds of hazardous substances in the risk site,

Second, it is non-toxic (or slightly toxic) and flammable,

Third, inflammable and harmful. The first two are very easy to identify,

Explosion detection, the second is poison detection, and the third is explosive detection if there are workers exposed to poison detection.

The turbine flowmeter for flammable gas liquid shall be selected for explosion detection, and the detector and alarm for harmful gas shall be selected for toxicity detection.

2. Determine the main purpose of testing and select the type of instrument (portable or mobile)

For the long-term operation of production and manufacturing or storage positions, the mobile detection and alarm instrument is used; for other items such as maintenance detection, emergency detection, incoming detection and tour detection, the portable (or pocket) instrument is used.

3. Establish the test target and select the best instrument model and specification

When selecting the instrument model and specification, the following contents shall be taken into account: the flowmeter sensor model and specification includes three themes: manufacturer, function index value and detection principle,

◆ the manufacturer is honest and trustworthy, has good reputation and guaranteed the quality of production and manufacturing. According to ISO9002 quality management system certification, it has CMC production license granted by the quality supervision unit, and has fire safety and explosion-proof certificate.

◆ the function index value of the selected model and specification products shall conform to the national standards gb12358-90, gb15322-94, GB16808-1997 and other specifications.

◆ the basic principle of the instrument detection shall be integrated into the provisions of detection target and natural environment.

Overview of hazardous gas detectors:

Hazardous gas detector is a component that converts the content of harmful substances in the air into electronic signals. After the electronic signal caused by the controller is solved, enlarged and transformed by electronic circuit, the display information and alarm of hazardous gas content will be maintained. It can be seen that the controller is the basic and key component of the harmful substance detection and alarm instrument, and its quality determines the quality and function index value of the harmful substance detection and alarm instrument.

The controller is applied in the field, and bears all kinds of hazards of extreme natural environment and atmosphere. It is the controller of mobile instrument. It operates continuously for a long time, and has the limits of explosion-proof type and power supply system volume. Therefore, the regulations on hazardous gas detector are very strict.