Introduction to the Selection Criteria of Toxic and Hazardous Gas Detectors
In different places, the types of gases that need to be detected are also different. In some places that are explosion-proof areas, the gas detector also needs to be of an explosion-proof grade. In some places where it is inconvenient for employees to enter and exit, it is recommended to use online gas detection instruments.
The first step is to confirm the types of gases to be detected and their respective concentration requirements.
For different types of gases, according to the impacts they cause, there will be different concentration requirements. In some places, as long as it is necessary to detect whether there is gas leakage, a higher sensitivity to the lower limit of the instrument is required.
There are mainly two types of gas detectors that are most commonly used. One is the portable gas detector, and the other is the fixed (online) gas detector.
Currently, most enterprises mostly use portable gas detectors. This type of instrument is small in size and easy to operate. It can be carried to different places for detection. For detectors using the electrochemical principle, the battery can generally be used continuously for over a thousand hours, and some batteries can also be recharged. It is widely used by large enterprises. However, it also has its disadvantages. Disadvantage 1: It is not a continuous measurement. For example, in some enterprises, the measurement is only carried out once a day, so it cannot truly reflect the actual gas content throughout the day. Disadvantage 2: Due to its mobile design, it is likely to accelerate the inherent errors of the electronic components of the instrument, and it needs to be calibrated more frequently. Otherwise, the measurement accuracy is questionable. Disadvantage 3: The battery voltage and current will fluctuate or weaken, which will affect the measurement results. Disadvantage 4: In some production areas, it is inconvenient to use a portable detector for detection.
For fixed (online) gas detectors, they can well overcome the disadvantages of portable gas detectors. An online gas detector is a gas detection instrument fixedly installed in a certain production area. It is generally composed of three parts: a sensor, a cable, and a transmitter. The transmitter can transmit the measured value to a central control system such as a PLC or DSC through an analog quantity to display the value in real time and save the measurement data. In some enclosed spaces, such as infusion pipelines, reaction kettles, liquid distribution tanks, centrifuges, etc., it is necessary to detect the content of certain gases, and in this case, only an online gas detector can be used. The biggest disadvantage of an online gas detector is the high initial investment cost. Of course, the level of the cost depends on whether the using department can carefully consider its true value.
