What are the problems that gas detectors need to pay attention to?

Update:25-05-2019
Summary:

1: Pay attention to regular calibration and testing. Th […]

1: Pay attention to regular calibration and testing.

The toxic and harmful gas detector is also the same as other profiling instruments. It is measured by a relatively comparative method: the instrument is first calibrated with a zero gas and a gas of a standard concentration, and the specification curve is stored in the instrument. During the inspection and control, the instrument compares the electrical signal generated by the gas concentration to be measured with the electrical signal of the normal concentration, and calculates the accurate gas concentration value. Therefore, the instrument is zeroed at any time, and regular calibration of the instrument is an essential task to ensure accurate measurement of the instrument. The requirements clarify that many gas detectors are now able to replace the detection sensor, but this does not mean that a detector can be equipped with different detector probes at any time. Whenever a probe is replaced, in addition to the required sensor activation time, the instrument must be de novo calibrated. In addition, it is advocated that before the various instruments are used, the instrument should be tested for the standard gas to ensure the actual maintenance of the instrument.

2: Pay attention to the detection disturbance between various sensors.

In general, each sensor corresponds to a specific test gas, but any gas detector may not be a special effect. Therefore, when selecting a gas sensor, the detection disturbance of other sensors should be known as much as possible to ensure accurate detection of the specific gas.

3: Pay attention to the life of various types of sensors:

All types of gas sensors have a certain number of years of service, that is, the number of life. Generally speaking, in portable instruments, the LEL sensor has a longer life span and can be used for about three years; the photoionization detector has a life of four years or longer; the electrochemical specific gas sensor has a relatively short life. Some, generally in one to two years; the life of the oxygen sensor is the shortest, about a year or so. The life of an electrochemical sensor depends on the dryness of the electrolyte, so if it is not necessary for a long time, the seal can be extended to a lower temperature environment to extend the service life. Because of the relatively large size of the fixed instrument, the life of the sensor is also longer. Therefore, the sensor should be tested at any time, as much as possible during the useful life of the sensor, and if it fails, it should be replaced in time.

4: Pay attention to the concentration of the measuring instrument.

All types of toxic and harmful gas detectors have their own fixed detection scale. As long as the measurement is completed within the scale of its measurement, it will be protected. The instrument is accurately measured. If the long-term measurement exceeds the measurement scale, it may cause permanent damage to the sensor.

For example, the LEL detector, if accidentally used in an environment that exceeds 100% LEL, may completely burn the sensor. For toxic gas detectors, long-term operation at higher concentrations can also cause damage. Therefore, if the fixed instrument is declared to exceed the limit signal during operation, the measurement circuit should be closed immediately to ensure the safety of the sensor.