Guide to the selection of hazardous gas detectors

With the development of industrialization, toxic and harmful gases have become a source of danger that we cannot face in production and life. Including petrochemical enterprises, chemical industry, environmental emergency accidents, terrorist attacks, storage and transportation of dangerous goods, landfills and even municipal sewage treatment, various types of underground pipelines and so on, we may unknowingly be threatened by dangerous gases. .

The people-centered concept requires us to care about our health and safety at any time and place, and all kinds of leaks and explosions continue to cause social crises and the destruction of public property. However, the detection of various types of gases is always a complex task. It is even more difficult to select a suitable gas monitor. Based on decades of experience in gas detection at ISC (Industrial Scientific) companies around the world (including China), we compiled this selection guide to give readers an understanding of various sensing technologies for gas monitoring. The introduction of different instrument types will help the user to choose the most suitable gas monitor.

At present, the more common types of gas sensors for on-site detection include: electrochemical sensors, infrared sensors, catalytic combustion sensors, photoionization detectors, solid state sensors, and semiconductor sensors.

All gas sensor technologies are based on the physical or chemical nature of the gas, and are converted into electrical signals that can be processed, amplified, and transmitted by electronic circuits through optoelectronic technology. Therefore, as a relative detection technique, all gas monitoring instruments must often be calibrated with a standard concentration of gas. At the same time, although these sensors are more and more sophisticated in their manufacture, they are still unable to achieve the performance specifications of analytical instruments because of their own limitations, and they are also difficult to use as gas quantitative analyzers. The best application of their gas concentration readings is to use them. Do you indicate whether your site is safe or not? However, the relevant gas concentrations provided by these sensors will still play an important role in safety, environmental protection and public health. As a field safety instrument, such gas monitors will detect the concentration value in real time when harmful gas is present, and when it exceeds a certain limit, they immediately issue an alarm to guide people in their actions. In order to adapt to different uses, this kind of instrument generally adopts the portable or fixed method, has the characteristics of simple operation, convenient maintenance and reasonable price.

So far, there is no gas sensor for certain gas effects. If you need more selectivity, use an analytical instrument. There are many analytical instruments used for gas monitoring, such as Fourier transform infrared, gas chromatography, and mass spectrometry. These instruments can provide the most accurate and highly selective gas concentration data. However, they are generally expensive, and are not suitable for on-site gas monitoring due to high maintenance costs, long response times, large volumes, cumbersome operations, inability to immediately reflect field concentrations, and the like. As laboratory gas monitoring instruments, they often serve as the final judgement.

The detection of dangerous gases is a systematic management project. We need to determine the gases that need to be detected on the basis of understanding the occurrence, development, and existence of various types of harmful gases, and select suitable detectors to ensure the safety of various personnel and industrial and mining enterprises.

Confined spaces (including reaction tanks, oil tanks, lack of well ventilated workshops, underground pipelines, underground drains, underground storage tanks, cabins, etc.) are important sites for hazardous gas detection. Any person who is about to enter or has entered the confined space to work must constantly monitor the concentration of toxic and harmful gases inside the workplace, and these dangerous components may exist before the workers enter the confined space, or because they During the formation of activities. The vast majority of accidents are caused by the lack of detection of dangerous gases before and during work in confined spaces.

Petrochemical and other chemical companies are places where poisonous and harmful gases are relatively common. The occurrence and leakage of flammable and explosive gases and toxic and hazardous gases can occur from raw materials, production processes, and product storage and transportation.

With the wide application of industrial products, the handling of environmental emergency accidents is also increasingly placed in front of all levels of governments and accident handling teams. How to monitor toxic and harmful gases before accidents, track toxic and harmful gases during accidents, and detect environmental and personnel residues after an accident, which is also the most basic of gas monitoring instruments in environmental emergency accidents. application.