How to choose a gas detector

Gas detector is mainly used for toxic, harmful, combustible gas detection combustible gas detector, toxic gas detector is located in coal mines, petroleum, chemical, gas transmission and distribution, biochemical medicine, agricultural capital, pesticides, construction materials, coking, building materials and other fields Have applications. For all kinds of different production occasions and testing requirements, it is necessary for every person engaged in safety and health work to pay attention to selecting the appropriate gas detector. Here we will give an introduction to the use of some gas detectors for your reference.

1) The optional gas detector must first confirm the type and concentration range of the gas 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, light ionization detection should be selected considering that it may cause low levels of poisoning of humans, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, lipids, and so on. Instrument, and never use the LEL detector to deal with it, 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.

2) Determine the use case: The type of gas detector is different depending on the industrial environment.

A) Fixed Gas Detector: This is a detector that is used 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 that is composed of transmissions are integrally installed at the inspection site, and a secondary instrument composed of a circuit, a power supply, and a display alarm device is integrally installed in a safe place to facilitate monitoring. Its detection principle is the same as that described in the previous section, but it is more suitable for the continuous and long-term 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, for example, to select the most effective height of the sensor installation according to the specific gravity of the gas.

3) Portable Gas Detector: Due to its convenient operation and small size, the portable instrument 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 type of LEL detector, PID, and compound instrument are used. The use of rechargeable batteries (some have used memoryless nickel-metal hydride or lithium-ion batteries) makes them generally capable of continuous operation for nearly 12 hours. Therefore, gas detectors are increasingly used as such instruments in various factories and health departments. wide.

Gas detectors, also known as gas alarms, are used on open occasions, such as in open workshops where such instruments are used as safety alarms. A diffuse gas detector can be worn on-the-spot because it can display continuously, in real time, and accurately. The concentration of toxic and harmful gases on site. Some of these new types of instruments are also equipped with vibration warning accessories - to avoid audible alarms in noisy environments, and to install computer chips to record the peak, STEL (15 minutes short-term exposure level) and TWA (8 hours statistics Weighted Average) --- Provides specific guidance for worker health and safety.

If entering a confined space, such as a reaction tank, storage tank or container, sewer or other underground pipelines, underground facilities, closed agricultural granaries, railroad tankers, shipping cargo tanks, tunnels, etc., the personnel must be inspected 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 gas in the general sense is lighter. Most of them are distributed in the upper part of the confined space; the proportion of carbon monoxide and air is almost the same and is generally distributed in the middle of the confined space; while the heavier gas such as hydrogen sulfide exists in the confined The lower part of the space. At the same time, oxygen concentration is also one of the types that must be tested.

In addition, a gas 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 be equipped with a built-in pumping function - so that it can be detected in non-contact, sub-area; with a multi-gas detection function - to detect hazardous gases in different spatial distributions, including inorganic Gas and organic gases; Oxygen detection function - to prevent oxygen deficiency or oxygen enrichment; small size, portable instruments that do not affect the work of workers. 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.

When toxic gas detectors are used in industrial hygiene inspections and health investigations, instruments with data records and statistical calculations as well as instruments that can be connected to computers are very convenient to use.

At present, with the development of manufacturing technology, portable gas detectors, or composite gas detectors or multiple gas detectors are also a new choice for us. Since this detector can be equipped with multiple gas (inorganic/organic) detection sensors on a host computer, it has the characteristics of small size, light weight, corresponding rapidity, and simultaneous multi-gas concentration display. More importantly, the price of pumped composite gas detectors is lower than that of multiple single diffusion gas detectors and is more convenient to use. It should be noted that when selecting such detectors, it is best to select an instrument that has the ability to switch each sensor individually to prevent the use of one sensor from affecting other sensors. At the same time, in order to avoid clogging of the suction pump due to water ingress, it is also safer to select a smart pump design with a pump stop alarm.