Selection criteria for toxic and hazardous gas detectors
Selection criteria for toxic and hazardous gas detectors
Different types of places, the need for ** and health requirements are not the same, in some places, the gas content is a very important indicator, it will affect the place of life and safety of the staff, as well as explosion-proof and other requirements, therefore, the various enterprises and the government testing part, are required to prepare a good toxic and hazardous gas detector, easy to monitor the place of the gas situation. The following selection of toxic and hazardous gas detector method for a brief introduction.
First of all, need to determine the use of gas detector places.
Different places, the type of gas to be detected is not the same. Some places are explosion-proof area, the detector also needs explosion-proof level instruments. In some places where it is not easy for staff to come and go, it is recommended to use online gas detection instruments.
The first step is to identify the type of gas to be detected and its respective concentration requirements.
Different types of gases have different concentration requirements depending on the impact they cause. In some places, only whether there is a gas leakage, the instrument's low-limit sensitivity requirements are higher.
There are two types of gas detectors in use: portable gas detectors and fixed (on-line) gas detectors.
Most enterprises now use portable gas detector, this type of instrument, small size, simple to manipulate, can be carried to different places for testing, the use of electrochemical principles of the detector, the general battery can be used continuously for thousands of hours, some batteries can be recharged. It is widely used by large enterprises. However, it also has its shortcomings, drawback 1: not continuous measurement, such as some enterprises, only to measure once, so can not really reflect the actual gas content throughout the day. Disadvantage two: mobile design, easy to accelerate the error inherent in the instrument's electronic components, the need for more frequent calibration, otherwise the correctness of the measurement is questionable. Disadvantage 3: Battery voltage and current may fluctuate or become weak, which may affect the measurement results. Disadvantage 3: In some parts of the production, portable detectors are not easy to detect.
For fixed (online) gas detector, can be very good to overcome the shortcomings of portable gas detector. Online gas detector, it is fixed installed in a production part of the gas detection instrument, generally by the sensor, cable and transmitter three parts. The transmitter can transmit the measurement value through analog to PLC or DSC and other central control system to display the value in real time, as well as save the measurement data. In some confined spaces, such as liquid pipelines, reaction kettles, liquid distribution tanks, centrifugal separators, etc., which need to detect the content of certain gases, which will only use the online gas detector. Online gas detector * big disadvantage is the initial investment cost is high, of course, the cost of the high and low, depending on the use of part of the good to consider where it is really worth it.
