Calibration and maintenance of vacuum gauges: key steps to ensure measurement accuracy

As a precision measuring tool, vacuum gauges are widely used in scientific experiments, industrial production, and vacuum technology. Due to their wide measurement range and their common use in high-precision environmental monitoring, it is critical to maintain the measurement accuracy of vacuum gauges. To ensure long-term stable operation of vacuum gauges, regular calibration and maintenance are key steps that cannot be ignored.

1.Calibration of vacuum gauges
Calibration standards and methods
The calibration of vacuum gauges depends on an accurate standard pressure source. Common calibration methods include the comparison method and the direct method. The comparison method compares the vacuum gauge to be calibrated with a standard vacuum gauge of known accuracy to ensure that its measured value is consistent with the standard value. The direct method calibrates the reading of the vacuum gauge by using a known standard gas pressure source, such as the saturated vapor pressure of argon and nitrogen. Common calibration devices include gas standards and diaphragm standard devices.

Calibration process
During the calibration process, the zero state of the vacuum gauge must first be confirmed to ensure that it is not offset. Then, by adjusting the standard pressure source to connect to the vacuum gauge, and gradually adjusting the pressure, compare multiple points from high pressure to low pressure, and record the deviation between the reading of each pressure point and the standard value. The calibration data should be recorded in detail and a calibration report should be formed for subsequent reference.

Calibration cycle
The calibration cycle of the vacuum gauge varies according to its frequency of use, environmental conditions and accuracy requirements. Generally speaking, industrial vacuum gauges should be calibrated at least once a year, while high-precision vacuum gauges for scientific research purposes may need to be calibrated once a quarter or monthly.

2.Maintenance of vacuum gauge
Regular inspection and cleaning
Long-term use of the vacuum gauge may cause dust accumulation, gas contamination or other material deposition on the sensor surface, which will affect its measurement performance. Clean the sensor surface, connectors and external components regularly to ensure that they are free of dust and contaminants. Avoid using corrosive or irritating chemicals when cleaning, and it is recommended to use non-woven fabrics or special cleaning tools.

Pipeline and sealing inspection
The vacuum gauge is usually connected to the vacuum system through a pipeline. Leakage in the pipeline, loose joints or aging of the sealing ring may cause inaccurate vacuum gauge readings. Therefore, regularly check the sealing of the pipeline connection to confirm whether there are minor leaks. When a leak is found, the sealing ring should be replaced or the joint should be tightened in time.

Sensor and display system inspection
For electronic vacuum gauges, the response sensitivity of the sensor needs to be checked regularly. Aging or damage of the sensor will cause reading drift or slow response, affecting the accuracy of the vacuum gauge. The display system should also be checked regularly to confirm whether the signal processing is stable and the display is accurate.

Avoid external interference
The vacuum gauge should avoid external vibration, temperature fluctuations and electromagnetic interference when measuring with high precision. The vacuum gauge should be installed in a stable environment to avoid strong vibration and temperature difference changes from interfering with the measurement results.

3.Common troubleshooting
Inaccurate measurement
If the vacuum gauge reading deviates from the actual value, it may be due to sensor damage, pipeline leakage or system contamination. At this time, you should first check the sealing of the connection, clean the sensor surface, and perform zero calibration if necessary.

No display or freeze
For electronic vacuum gauges, if the display does not work or freezes, it may be a power supply problem or circuit failure. At this time, check whether the power connection, line and display are normal.

Reading drift
If the reading of the vacuum gauge drifts in a short period of time, it is usually related to ambient temperature changes or sensor aging. The ambient temperature should be checked for stability and the vacuum gauge should be recalibrated.

The calibration and maintenance of the vacuum gauge is the core step to ensure its long-term reliable operation and high-precision measurement. Through regular calibration and maintenance, error accumulation can be effectively avoided, the service life of the equipment can be extended, and accurate measurement in different application environments can be ensured. Regular inspection, cleaning and proper environmental control are the key to maintaining the performance of the vacuum gauge.