What are gas detectors and how does it work?

Gas detectors are detection instruments used to detect, analyze and measure the concentration of one or more gases in the air, primarily using gas sensors to detect the type and concentration of gases present in the environment.

These devices play an important role in a variety of industrial, research and environmental applications, especially in locations where harmful gases or low oxygen concentrations may be present.

Gas Detector Uses

Gas detectors can monitor harmful gases in the air in real time so that leaks can be detected in a timely manner. Not only do they help people understand air pollution and fire hazards and take appropriate measures to avoid them, they are also widely used in industrial production.

Because the gas detector can accurately determine the volume of the gas, so as to understand the composition of the gas, in order to monitor and manage the industrial production process, and prevent accidents from occurring and spreading by alarming and disconnecting the gas, and safeguard the working environment of the factory and the safety of employees.

The real-time monitoring of gas detectors is an important guarantee to realize production safety, environmental protection monitoring, public health, transportation and many other fields. By realizing real-time monitoring and early warning of gas concentration in the environment, potential safety hazards and environmental pollution problems can be found and solved in time.

Gas detector working principle

Gas detectors mainly use gas sensors to detect the presence of gas species in the environment, gas sensors are used to detect the composition and content of the gas sensor. Gas sensors are categorized by the purpose of detection, as long as the sensor is used to detect the composition and concentration of the gas are called gas sensors, regardless of the physical principle, or chemical principle.

Common types of gas detector sensors are electrochemical, infrared, catalytic combustion, semiconductor and so on.

1, Electrochemical sensors

By electrochemical reaction with the detected gas to generate current, the current size is proportional to the gas concentration, so that the gas concentration is converted into an electrical signal. Advantages are high precision, good selectivity, good detection of specific gases, commonly used in the detection of toxic gases. The disadvantage is that the life is relatively short, need to regularly replace the electrolyte.

2, Infrared sensor

The use of different gases to specific wavelengths of infrared absorption properties, when the infrared light through the air containing the detected gas, its intensity will be weakened by gas absorption, by detecting changes in the intensity of infrared light to determine the gas concentration. Its advantages are high stability, long life, strong anti-interference ability, suitable for detecting high concentration and stable nature of the gas. However, the cost is high, and the sensitivity of low concentration gas detection is relatively low.

3、Catalytic combustion sensor

In the presence of combustible gases, combustible gases in the catalyst under the action of combustion, so that the sensor temperature rises, resistance changes, through the measurement of resistance changes to detect the gas concentration. It has high sensitivity and fast response speed for combustible gas detection, but it is easy to be affected by sulfide and other impurities and poisoning failure.

4、Semiconductor sensor

Based on the semiconductor material in contact with the gas, its conductivity changes in the principle of work. Low cost, fast response speed, can detect a variety of gases. But the selectivity is poor, easily affected by ambient temperature, humidity, precision is relatively low.

5, Photoionization (PID) sensor

The use of ultraviolet light emitted by the ultraviolet lamp, the measured gas molecules ionized into positively charged ions and negatively charged electrons. Under the action of the electric field, the ions and electrons move directionally to form a current, the current size is proportional to the gas concentration, thus realizing the detection of gas concentration.

The PID sensor is extremely sensitive to trace gases such as volatile organic compounds (VOCs), has a fast response time, and can detect a wide range of gases without causing permanent damage, making it easy for subsequent analysis. However, its response to different gases varies and needs to be calibrated for different gases and is affected by other interfering gases in the environment.

Gas detector use precautions

1, The range of the detector

Various toxic and hazardous gas detectors have their fixed detection range. Only when measured within its measuring range, the instrument can ensure accurate measurement. Long-term measurement beyond the measuring range may cause permanent damage to the sensor.

2, Interference of different sensors

In the selection of a gas sensor, you should know in detail whether the other gases on the sensor detection interference, so as to ensure that the gas detector detects the authenticity of the gas value.

3, Regular calibration equipment

Regular calibration of the gas detector is required to ensure that the detection results are accurate and reliable. In accordance with the guidelines in the gas detector operation manual, regular calibration of the equipment.

With the rapid development of industry, environmental pollution, air quality, gas monitoring problems are more and more, for the gas detector sensing accuracy, anti-interference ability requirements are also higher and higher.

At present, there are many types of gas detectors, and different types of gas detectors configured with different gas sensors, only for the specific actual situation and environmental complexity of the selection of the appropriate gas detector, in order to effectively meet the monitoring needs at the same time, reduce enterprise costs.