How to choose the toxic hazard that suits you in many brands and models, under various production occasions and testing requirements
gas detectorIt is something that every procurement personnel engaged in this industry must pay more attention to and understand.
We will introduce you to different situations, hoping to help you purchase a satisfactory detector.
1) The type and concentration range of toxic gas detection gas you need:
The types of gases encountered by each production department are different. When choosing a gas detector, consider all possible scenarios. If methane and other less toxic alkanes are predominant, choosing a LEL detector is undoubtedly the most appropriate. This is not only because the LEL detector has a simple principle and wide application, but also has the characteristics of easy maintenance and calibration. If there is a toxic gas such as carbon monoxide or hydrogen sulfide, a specific one should be given priority
gas detectorto ensure the safety of workers. If it is more organic toxic and harmful gases, considering that it may cause poisoning at a lower concentration, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia (amines), ethers, alcohols, lipids, etc., you should choose a photoionization detector, and never use a LEL detector to deal with it, because this may lead to casualties.
If the gas type covers the above types of gases, choose oneComposite gas detectorIt may achieve twice the result with half the effort.
2) About the occasion of use:
Different use environments,
gas detectorThe choice of species will also vary.
A）fixedgas detector：
This is the most commonly used detector in industrial installations and in the production process. It can be installed at specific detection points to detect specific gas leaks. The fixed detector is generally two-body, with a sensor and a transmission head installed at the testing site, and a secondary instrument composed of a circuit, power supply and display alarm device 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, long-term stability and other characteristics required by fixed detection in terms of process and technology. They should also be selected according to the type and concentration of gas in the field, and they should also be installed in the most likely part of the specific gas leakage, such as choosing the most effective height for sensor installation according to the specific gravity of the gas.
B）portablegas detector：
Due to the easy operation and small size of the portable instrument, it can be carried to different production parts, and the electrochemical detector is powered by alkaline batteries, which can be used continuously for 1000 hours. The new LEL detectors, PIDs, and composite instruments are increasingly used in various factories and health sectors due to the use of rechargeable batteries (some already with memory-free nickel-metal hydride or lithium-ion batteries), which allow them to operate continuously for almost 12 hours.
If such instruments are used as safety alarms in open settings, such as in open workshops, a body-worn diffusion gas detector can be used, as it can continuously and accurately display the concentration of toxic and harmful gases on site. Some of these new instruments also come with vibration alarm attachments – to avoid audible alarms in noisy environments and computer chips to record peaks, STEL (15-minute short-term exposure level) and TWA (8-hour statistical weighted average) – to provide specific guidance for worker health and safety.
If it is entering a confined space, such as a reaction tank, storage tank or container, sewer or other underground pipeline, underground facilities, agricultural closed granaries, railway tankers, shipping cargo holds, tunnels and other work occasions, it must be tested before personnel enter, and it must be tested outside the confined space. At this point, a multi-gas 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 very different. For example, the specific gravity of flammable gas in the general sense is relatively light, and most of them are distributed in the upper part of the confined space; carbon monoxide has a similar specific gravity to air and is generally distributed in the middle of confined spaces; Heavier gases such as hydrogen sulfide are present in the lower part of the confined space (as shown in the figure). 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 possible volatilization and leakage of organic substances in the tank are taken into account. Hence a complete confined space
gas detectorIt should be one with built-in pump suction function - so that it can be detected non-contact, by site; Multi-gas detection function - to detect hazardous gases with different spatial distributions, including inorganic and organic gases; With oxygen detection function - prevent hypoxia or oxygen enrichment; Portable instrument that is compact and does not affect the worker's work. Only in this way can the absolute safety of workers entering confined spaces be guaranteed.
In addition, after entering the confined space, the gas components in it should be continuously tested to avoid changes in the concentration of volatile organic compounds or other toxic and harmful gases caused by personnel entry, sudden leakage, temperature and other changes.
If used for emergency accidents, leak detection and inspection, pump-suction instruments with short response time, high sensitivity and resolution should be used, so that the orientation of the leak point can be easily determined.
In the case of industrial hygiene inspections and health surveys, instruments with functions such as data recording and statistical calculations, as well as computer connection, are very convenient to use.
Under the current technical conditions, with the development of manufacturing technology, portable multi-gas (composite) detector is also a new choice for us. Since this detector can be equipped with the required multiple gas (inorganic/organic) detection sensors on a single main unit, it has the characteristics of small size, light weight, corresponding speed, and simultaneous display of multiple gas concentrations. What's more, pump suctionComposite gas detectorThe price is more than multiple single diffusionsgas detectorIt is cheaper and more convenient to use. It should be noted that when choosing this type of detector, it is best to choose an instrument with the function of switching and closing each sensor separately to prevent the use of other sensors due to damage to one sensor. At the same time, in order to avoid blockage of the suction pump due to water inlet and other conditions, it is safer to choose an instrument with an intelligent pump design with a pump stop alarm.
