How to choose a gas detector

      Everyone must be familiar with the role of gas detectors. They can provide the concentration of the gas that needs to be detected in the working environment in a timely manner. Based on these data, the staff can scientifically analyze whether to enter the environment to work or take corresponding measures to reduce the concentration of toxic gases in the working environment. Choosing a qualified gas detector is crucial to the safe production of special operations industries. So how to choose a gas detector?

     First, determine what kind of gas you need to detect and confirm the concentration range of the gas.

 　Different companies will encounter different types of gases. When choosing a gas detector, you must consider what kind of gas you will encounter when entering the environmental area. If methane and other less toxic alkanes are the majority, it would be most appropriate to choose an LEL detector. Because the principle of the LEL detector is simple and widely used, it is also easy to maintain and calibrate. If there are toxic gases such as carbon monoxide and hydrogen sulfide, you must give priority to choosing a specific gas detector to ensure the safety of the workers. If there are more organic toxic and harmful gases, considering that the concentration that may cause poisoning to people is low, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, fats, etc., you should choose the photoionization detector introduced in the previous chapter, and never use the LEL detector to deal with it, because it may cause casualties. If the gas types cover the above types of gases, Haigu experts suggest: choosing a composite gas detector may achieve twice the result with half the effort.

　 Secondly, depending on the industrial environment where you work, you should choose a different type of gas detector. We will introduce different types of gas detectors to you.

　The first type of fixed gas detector. This is a detector that is used more frequently in industrial devices and production processes. It can be installed at a specific detection point to detect specific gas leaks. Fixed detectors are generally two-body, with a detection head consisting of a sensor and a transmitter installed as a whole at the detection site, and a secondary instrument consisting of a circuit, power supply and display alarm device installed as a whole in a safe place for easy monitoring. Its detection principle is the same as described in the previous section, but in terms of process and technology, it is more suitable for the continuous and long-term stability required by fixed detection. They should also be selected according to the type and concentration of the gas on site, and at the same time, they should be installed at the location where the specific gas is most likely to leak, such as choosing the most effective height for sensor installation based on the specific gravity of the gas, etc.

     The second type of portable gas detector. Because the portable instrument is easy to operate and compact, it can be carried to different production sites. The electrochemical detector is powered by alkaline batteries and can be used continuously for one thousand hours; the new LEL detector, PID and composite instrument use rechargeable batteries (some have adopted memoryless nickel-metal hydride or lithium-ion batteries), so that they can generally work continuously for nearly twelve hours. Therefore, this type of instrument is increasingly used in various factories and health departments. If it is used as a safety alarm in an open place, such as an open workshop, a wearable diffusion gas detector can be used, because it can continuously, real-time and accurately display the concentration of toxic and harmful gases on site. Some of these new instruments are also equipped with vibration alarm accessories---to avoid not hearing the sound alarm in a noisy environment, and install computer chips to record peak values, STEL (fifteen-minute short-term exposure level) and TWA (eight-hour statistical weighted average)---to provide specific guidance for worker health and safety.

Only by choosing a suitable gas detector can the accuracy of the test results be effectively guaranteed. At the same time, whether the method of using the gas detector is correct will also affect the accuracy of the test results. Therefore, when using the gas detector, it must be used in accordance with the instructions.