Only in this way can absolute safety be guaranteed for workers entering confined spaces. After entering the confined space, the gas composition should be continuously tested to avoid changes in the concentration of volatile organic compounds or other toxic and harmful gases caused by human entry, sudden leakage and temperature changes. If used for emergency, leak detection, and inspection, pump-suction instruments with short response times, high sensitivity, and high resolution must be used to determine the location of leak points.
Instruments with data logging, statistical calculations, and computer connectivity are convenient to use in industrial health testing and health surveys.
At present, with the development of manufacturing technology, portable multi-gas detector is also a new choice.
Since the detector can be installed with multiple gas (inorganic organic) detection sensors on one main unit, it has the characteristics of small size, light weight, fast response, and can display multiple gas concentrations at the same time.
What's more, pump-suction compoundinggas detectorThe price is cheaper than multiple single diffusion gas detectors, making it easier to use.
It should be noted that when choosing this type of detector, it is best to choose an instrument with the function of switching and closing each sensor separately to avoid damage to one sensor that affects the use of other sensors.
At the same time, in order to avoid clogging the suction pump due to water inlet, a safer option is a smart pump with a pump stop alarm.
in usegas detectorThe following issues need to be paid attention to: 1. Note that frequent calibration detection of toxic and harmful gas detectors, like other analytical detection instruments, are determined by the relative comparison method:
First, the instrument is calibrated with zero gas and standard concentration gas, and the standard curve is obtained and stored in the instrument. During the measurement process, the instrument compares the electrical signal generated by the measured gas concentration with the electrical signal of the standard concentration to calculate the accurate gas concentration.
Therefore, it is necessary to zero the instrument at any time and calibrate the instrument regularly to ensure the accuracy of instrument measurement.
It should be noted: there are a lot of them at the momentgas detectorThe detection sensor can be replaced, but this does not mean that a detector can be equipped with a different detector probe at any time. Whenever the probe is replaced, the instrument must be recalibrated in addition to the sensor's activation time. In addition, it is recommended to test the standard gas before using various instruments to ensure the protection of the instrument.
Second, pay attention to simultaneous interpretation interference between different sensors. In general, each sensor corresponds to a specific detection gas, but no gas detector is absolutely effective. Therefore, when choosing a gas sensor, you should try to understand the detection interference of other gases on the sensor to ensure its accurate detection of specific gases.
3. Pay attention to the lifespan of various sensors. variousGas sensorBoth have a certain service life, that is, the service life. Generally speaking, in portable instruments, LEL sensors have a longer lifespan and can be used for about 3 years; The lifespan of the photoionization detector is 4 years or more; The lifespan of electrochemical specific gas sensors is relatively short, generally 1 to 2 years; The oxygen sensor has the shortest lifespan, about 1 year a year.
The lifespan of an electrochemical sensor depends on how dry the electrolyte is, and if it is not used for a long time, sealing it in a low-temperature environment can extend its life.
Due to the relatively large size of the fixed instrument, the service life of the sensor is also relatively long. Therefore, sensors must be detected at all times, used within the validity period of the sensor as much as possible, and replaced in time in case of failure.
4. Pay attention to the concentration measurement range of the testing instrument. All kinds of toxic and harmful gas detectors have a fixed detection range. Accurate measurements can only be made when the measurement is completed within the measurement range. If the measured value is out of the measurement range for an extended period of time, it can cause permanent damage to the sensor.
For example, if a LEL detector is inadvertently used in an environment with more than 100% LEL, it may completely burn out the sensor. Toxic gas detectors work for a long time at high concentrations and can also cause damage. Therefore, if a fixed meter emits an overrun signal, the measurement circuit should be turned off immediately to ensure the safety of the sensor.