How to pick a gas detector for poisonous and dangerous gases
The gas type and concentration range to be detected: When choosing a gas detector, all possible situations should be considered. If methane and other less toxic alkanes are mostly, it is undoubtedly the most appropriate to choose a LEL detector. This is not only because of the LEL The detector is simple in principle and widely used, and it also has the characteristics of convenient maintenance and calibration. If there are toxic gases such as carbon monoxide and hydrogen sulfide, it is necessary to choose a specific gas detector first to ensure safety. If more organic and toxic Harmful gases, considering that they may cause employees and low concentrations of air poisoning, such as aromatic hydrocarbons, alcohols, ammonia, ethers, fats, etc., you should choose photoionization detectors instead of LEL detectors. Because it may endanger the lives of employees.
Determine where to use:
Different industrial environments require different types of gas detectors.
Portable Gas Detector:
The portable instrument is easy to operate, small in size, and can be carried to different production sites. The electrochemical detector is powered by batteries and can be used continuously. Hydrogen or carp ion batteries), so that they can generally work continuously for nearly 1 day.
If this type of instrument is used as a safety alarm in an open place, such as an open workshop, a portable diffusion gas detector can be used, because it can continuously, real-time, and accurately display the concentration of toxic and harmful gases on site. This is Some of the new instruments of this class are also equipped with vibration alarm accessories to avoid inaudible alarms in noisy environments, and install computer chips to record peak, STEL (15-minute short-term exposure level) and TWA (8-hour statistical weighted average) Provide specific guidance on worker health and safety.
If entering a confined space, such as reaction tanks, storage tanks or containers, sewers or other underground pipes, underground facilities, agricultural airtight granaries, railway tank cars, shipping cargo holds, tunnels and other workplaces, inspections must be carried out before personnel enter , and the detection must be carried out outside the confined space. At this time, it is necessary to choose a multi-gas [Industrial Electrical Network-cnelc] detector with a built-in sampling pump. Because the gas distribution in different parts (upper, middle and lower) in the confined space It is very different from the type of gas. For example: the proportion of combustible gases in the general sense is relatively light, and most of them are distributed in confined spaces. The specific gravity of carbon monoxide is similar to that of air. Heavier gases such as hydrogen exist in the lower part of the confined space. At the same time, the oxygen concentration is also one of the types that must be detected. In addition, if the possible volatilization and leakage of organic substances in the tank are considered, a detector that can detect organic gases is also Required. Therefore, a complete gas detector in a confined space should have a built-in pumping function for non-contact, sub-site detection and a multi-gas detection function to detect dangerous gases distributed in different spaces, including inorganic gases and organic gases. Oxygen detection function prevents hypoxia or enrichment. It is a portable instrument that is small in size and does 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, the gas composition in it must be continuously detected to avoid changes in the concentration of volatile organic compounds or other toxic and harmful gases due to personnel entry, sudden leakage, and temperature changes.
If it is used for emergency accidents, leak detection and inspection, it should use pump suction type, short response time, high sensitivity and resolution instruments, so that it is easy to judge the location of the leak point.
Fixed gas detection protocol:
This is a detector that is widely used in industrial devices and production processes. It can be installed on specific detection points to detect specific gas leaks. Fixed detectors are generally two-body, consisting of sensors and transmitters The detection head is installed on the detection site as a whole, and it is a secondary instrument composed of circuit, power supply and display alarm device.
It is installed in a safe place as a whole and is convenient for 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 fixed detection in terms of process and technology. They also need to be based on the type of gas on site. At the same time, we should also pay attention to installing them in the most likely leaking parts of specific gases, such as selecting the most effective height of sensor installation according to the specific gravity of the gas, etc.
