How to choose poisonous and harmful gas detector

For various types of production sites and testing requirements, selecting the right gas detector is a must for everyone involved in safety and hygiene. Here we will introduce some specific situations for your reference.

Confirm the gas type and concentration range to be detected:

The gas types encountered by each production department are different. When selecting a gas detector, all possible conditions must be taken into consideration. If methane and other less toxic alkanes are present, selecting the LEL detector is undoubtedly the most appropriate. This is not only because of the simple principle and wide application of the LEL detector, but also its convenient maintenance and calibration features. If there are toxic gases such as carbon monoxide and hydrogen sulfide, a specific gas detector must be selected to ensure the safety of workers. If there are more organic toxic and harmful gases, considering the low concentrations that may cause human poisoning, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, fats, etc., you should choose the light that was introduced in the previous chapter. Do not use an LEL detector to ionize the detector, as this may result in personal injury or death.

If the gas species covers the above types of gases, selecting a composite gas detector may achieve a multiplier effect.

Determine the use of the occasion:

The type of gas detector is different depending on the industrial environment.

A), fixed gas detection proposal:

This is a detector that is used more often in industrial installations and production processes. It can be installed at specific detection points to detect specific gas leaks. The fixed detector is generally a two-body type. A sensor and a detection head composed of transmissions are integrally installed at the inspection site. Secondary instruments including a circuit, a power supply, and an alarm display device are integrally installed in a safe place for easy monitoring. Its detection principle is the same as described in the previous section, but it is more suitable for the continuous and long-time stability required by the fixed test in terms of technology and technology. They also need to be selected according to the type and concentration of gas in the site, and they should also be careful to install them on the site where the specific gas is most likely to leak, such as choosing the most effective height of the sensor installation according to the specific gravity of the gas.

B) Portable gas detector:

Because the portable instrument is easy to operate and small in size, it can be carried to different production sites. The electrochemical detector is powered by alkaline batteries and can be used continuously for 1,000 hours. The new LEL detector, PID and compound instruments use rechargeable batteries (some The use of non-memory helium-hydrogen or helium-ion batteries makes them generally capable of continuous operation for nearly 12 hours. As a result, these instruments are used more and more widely in various factories and health departments.

If it is in an open place, such as an open work shop using such an instrument as a safety alarm, a diffuse gas detector can be worn with it, because it can continuously, in real time, accurately display the concentration of toxic and harmful gases on site. Some of these new instruments are also equipped with vibration alarm attachments to avoid audible alarms in noisy environments, and computer chips are installed to record peaks, STELs (short-term exposure levels for 15 minutes) and TWA (average of 8-hour statistical weights). ) Provide specific guidance for worker health and safety.

If you enter a confined space, such as a reaction tank, storage tank or container, sewer or other underground pipelines, underground facilities, closed agricultural granaries, railway tankers, ship cargo holds, tunnels, etc., the personnel must be tested before entering. , but also to test outside the confined space. In this case, a multigas detector with a built-in sampling pump must be selected. Because the gas distribution and gas types in different parts of the confined space (upper, middle, and lower) are quite different. For example, the proportion of combustible gases in the general sense is light. Most of them are distributed in confined spaces. The proportion of carbon monoxide and air in the confined space is almost the same. Generally, they are distributed in confined spaces, while heavy gases such as hydrogen sulfide exist in confined spaces. The lower part of the space. At the same time, oxygen concentration is also one of the types that must be detected. In addition, a detector that can detect organic gases is also needed if the possible volatilization and leakage of organic substances in the tank are taken into consideration. Therefore, a complete closed-space gas detector should have a built-in pumping function so that it can detect non-contact, sub-area detection with multiple gas detection functions to detect different spatial distribution of hazardous gases, including inorganic gases and organic gases. Prevents oxygen-deficient or helium-rich instruments that do not affect workers' work. Only in this way can the absolute safety of workers entering the confined space be guaranteed.

In addition, after entering the confined space, it is necessary to continuously test the gas components in order to avoid changes in concentrations of volatile organic compounds or other toxic and harmful gases caused by personnel entry, sudden leaks, and temperature changes.

If it is used for emergency accidents, leak detection and patrols, instruments with pumping, short response time, high sensitivity, and high resolution should be used. This can easily determine the location of the leak.

In the case of industrial hygiene tests and health surveys, instruments with data recording and statistical calculations and functions that can be connected to computers are very convenient to use.