As the national standard for toxic and harmful gas emission becomes more and more strict, it is strictly prohibited for enterprises to exceed the standard for gas emission, and for employees to exceed the standard for toxic gas content in the workplace. It is required for enterprises to install gas detector in the workplace and monitor the gas concentration in the workplace in real time. Of course, the purchase and use of instruments and matters needing attention is also an important premise to ensure the normal and stable work of the instrument.
The purchase of instruments should strictly follow the following points：
1.Confirm the gas type and concentration range to be detected：
All possible scenarios should be taken into account when selecting a gas detector.
①If methane and other less toxic alkanes are in the majority, the LEL detector is undoubtedly the most appropriate. This is not only because of the simple principle and wide application of LEL detector, but also because of its convenient maintenance and calibration. If the presence of carbon monoxide, hydrogen sulfide and other toxic gas, it is necessary to choose a specific gas detector to ensure the safety of workers.
②If there are more toxic and harmful organic gases, consider the low concentration that may cause human poisoning, such as aromatic hydrocarbon, halogenated hydrocarbon, ammonia (amine), ether, alcohol, fat, etc., you should choose the photoionization detector introduced in the previous chapter, and never use LEL detector to deal with, because it may cause human casualties
③If the gas category covers the above categories, the choice of a composite gas detector may be more efficient.
2.Note the concentration measurement range of the detection instrument:
All kinds of toxic and harmful gas detectors have their fixed detection range.
Only when the measurement is completed within the measuring range can the instrument be guaranteed to be accurate.
If the sensor is measured beyond the measurement range for a long time, it may cause permanent damage to the sensor.
For example, in the range of 0-100ppm, if accidentally used in an environment exceeding 100ppm, the sensor may completely burn out. Therefore, before purchasing equipment, be sure to confirm their range range.
3.Determine where to use it：
Industrial environment, the choice of gas detector types are also different.
A)Fixed gas detector: this is used in industrial installations and production process more detector.
①It can be installed at specific detection points to detect specific gas leaks.
②Its detection principle is the same as described in the previous section, only in the process and technology is more suitable for the fixed detection requirements of continuous, long-term stability and other characteristics.
③They should also be selected according to the type and concentration of the gas in the field, and they should be installed in the most likely place of leakage of a particular gas, such as the most effective height of the sensor installed according to the specific gravity of the gas.
B) Portable gas detector: the portable instrument is easy to operate, small in size, with built-in sampling pump, the detection speed is fast, high precision; It can be carried to different places for testing and can be used after starting up. As a kind of instrument, it is widely used in various factories and health departments.
4. Note the detection interference between various sensors
In general, each sensor corresponds to a specific detection gas, but no gas detector can be absolutely specific.Therefore, when selecting a gas sensor, it is necessary to understand the detection interference of other gases to the sensor as much as possible, so as to ensure its accurate detection of specific gases
5.Pay attention to the life of various sensors：
All kinds of gas sensors have a certain service life, that is, lifetime.
Generally speaking, in portable instruments, the life of LEL sensor can be used for about three years; Electrochemical specific gas sensors typically have a life span of two to three years;
The life of the electrochemical sensor depends on its electrolyte drying out, so if it is not used for a long time, it can be sealed in a lower temperature environment to extend its service life.Therefore, the sensor should be detected at any time and used as far as possible within the validity period of the sensor. Once the sensor fails, it should be replaced in time.