What Inspections Should Be Conducted After Buying Gas Detectors?
Appearance and functional inspection
1. Check the appearance and other items
Checking the appearance is the first thing we need to do after purchasing a gas detector. This is to avoid small problems that may occur during transportation or production assembly of the gas detector. We need to inspect the appearance of the gas detector for defects, cracks, or damage, check whether the entire component structure of the gas detector is complete, and at the same time check the machine model, label, manufacturer name, and manufacturing time on the gas detector body against the information provided in the manual or manufacturer to ensure accuracy. At the same time, we need to check the explosion-proof mark, measurement license mark, and number of this gas detector, which must be complete and clear. Some documents can be required from the manufacturer to provide.
2. Power on inspection
The operation of a gas detector requires a power supply, usually powered by a built-in battery. We need to turn on the switch and check if the gas detector is powered on normally. Some gas detectors can continue to work by replacing the battery, while others are equipped with a charger. For gas detectors equipped with a charger, we need to test if the charger is charging properly. If it is powered on normally, we need to check if the display screen of the gas detector is displaying normally.
3. Check if the sound and light alarm of the instrument is normal
For gas detectors with sound and light alarm signals, as they are powered by batteries, they should be able to emit sound or light indication signals that are significantly different from the alarm signal when displaying under voltage.
Indication error
We purchased a gas detector to detect gas concentration. The gas detector cannot display gas concentration accurately, as there may be errors. However, this error has a range, and if it exceeds this range, it means that the gas detector does not meet the standard. The specified indication error varies for different gases. For example, it is normal for the indication error of oxygen to be within ± 0.5% VOL.
Alarm error
As we mentioned above, there is an error in displaying numerical values. Therefore, for the alarm values of gas detectors, there is also a certain allowable error, because the instrument is affected by various factors and it is impossible to alarm at an accurate concentration every time. Therefore, the alarm concentration is allowed to have an error as long as the error is within the standard range. The alarm error varies for different gases, for example, the alarm error for oxygen is within ± 0.1% VOL.
Response time
Response time refers to the time required for the gas detector's reading to rise from zero to 90% of the stable reading that the instrument should reach. This time also has standard requirements, and this standard, like indication error and alarm error, varies for different gas response times. For example, the response time for oxygen is less than or equal to 20 seconds
Insulation withstand voltage
For gas detectors, there are still some insulation and voltage resistance standards that must be met. The standard requirements are: at room temperature: ≥ 100M Ω; after humid and hot conditions: ≥ 1M Ω. The insulation strength should be able to withstand 500V AC voltage for 1 minute without discharge or breakdown. Only when these are met can the gas detector meet the standards.
Through the introduction of the above points, we have a general understanding of the inspection technical standards for gas detectors, but there are still many details that need to be checked so that we can determine whether the gas detector we purchased meets the standards.
