Stainless steel pressure gauge verification process | Standard operating guide for pressure calibration equipment
Industrial pressure gauges require regular calibration and testing. Using the Air-Lac ALKB601 portable air pump as the pressure source, paired with the ALKC400D precision digital pressure gauge, the Y-100BF stainless steel pressure gauge is verified across its full range. The calibration covers both positive and negative pressures, employing a step-by-step pressure adjustment and verification process. By gently tapping the gauge case to read the measured value, the indication error and return error are calculated and compared to the allowable deviation. The pressure is smoothly adjusted throughout the process, and standard equipment is periodically verified and maintained daily to ensure standardized operations and compliance with accurate pressure gauge calibration data.
1. Calibration tool for pressure gauge
The entire verification process must strictly adhere to the current metrological technical specifications, primarily based on JJG52-2013 "Elastic Element Type General Pressure Gauges, Pressure Vacuum Gauges, and Vacuum Gauges". This standard is applicable to the initial verification, subsequent verification, and in-service inspection of elastic element type general pressure gauges, pressure vacuum gauges, and vacuum gauges, covering locally indicating pressure measuring instruments commonly used in industry.
II. Detailed Explanation of Operational Procedures
(I) Preliminary preparations
1. Environmental requirements
The temperature should be controlled at (20±2)℃, with a relative humidity of ≤85%RH, and there should be no condensation. Ensure that the site is free from vibration, dust, and corrosive gases.
2. Tool connection
• Connect the standard gauge ALKC400D and the verified pressure gauge Y-100BF to the ALKB601 output port in a sealed manner.
(II) Pressure gauge calibration process
1. Voltage boosting process
• First, open the air vent valve of ALKB601, then push the positive and negative pressure switch valve inwards (do not switch under pressure), adjust the fine adjustment knob counterclockwise to the appropriate position, and close the air vent valve.
• Use the pressure rod to apply pressure, stopping when the pressure reaches the verification point. Then, use fine adjustment to gradually increase the pressure clockwise to 0.4 MPa at the verification point. After the pressure stabilizes and the standard indicated value no longer fluctuates, check the pressure value of the verified pressure gauge. Next, gently tap the side of the verified pressure gauge's casing with your finger (do not tap the glass or tap hard), observe the pointer position, and record the indicated value after the tapping stabilizes. Use the indicated value after tapping as the actual measured verification reading for this pressure point, and calculate the error.
• Then use the pressure rod to apply pressure until it reaches the verification point, and then stop. Use the fine adjustment to slowly turn clockwise to adjust the pressure to 0.8 MPa at the verification point. Once the pressure stabilizes, tap the verified pressure gauge and record the value.
• Continue to press the hand lever until the pressure reaches approximately 1 MPa, then immediately use the fine adjustment to gradually increase the pressure clockwise to the verification point of 1.2 MPa. Once the pressure stabilizes, tap the verified pressure gauge and record the value.
Finally, continue to use the fine adjustment to slowly turn clockwise to the verification point of 1.6 MPa. Once the pressure stabilizes, tap the verified pressure gauge and record the value.
2. Decompression process
• First, slowly open the vent valve and reduce the pressure until it stops at the verification point. Close the vent valve and use the fine adjustment valve to slowly adjust it counterclockwise to the verification point of 1.2 MPa. Once the pressure stabilizes, tap the pressure gauge being verified and record the value.
• Perform the same operation with the verification points adjusted to 0.8 MPa and 0.4 MPa, check the pressure values of the verified pressure gauge, tap the verified pressure gauge, and record the indicated value after the tap becomes stable.
3. Pressure relief process
Open the vent valve in sequence, gradually release the pressure in the pipeline, and when the pressure is released to 0, the measurement is complete.
(III) Pressure gauge vacuum calibration process
1. Voltage boosting process
• First, remove the verified meter for measuring positive pressure and install the verified meter for measuring negative pressure. Pull out the positive and negative pressure switch valve (do not switch under pressure), then turn the ALKB601 fine adjustment knob clockwise to the appropriate position and close the air output valve.
• Use the pressure rod to evacuate the vacuum until it reaches the verification value, then stop. Use the fine adjustment knob to slowly adjust counterclockwise to the verification point of -0.02MPa. Once the pressure stabilizes, tap the verified pressure gauge and record the value.
• Perform the same operation at the verification points of -0.04MPa, -0.06MPa, -0.08MPa, and -0.095MPa, check the pressure values of the verified pressure gauge, tap the verified pressure gauge, and record the indicated value after it stabilizes.
2. Decompression process
• First, slowly open the air output valve to reduce the pressure to around the verification value and then stop. Close the air output valve, use the fine adjustment valve to slowly adjust clockwise to the verification point of -0.08 MPa. Once the pressure stabilizes, tap the verified pressure gauge and record the value.
• Perform the same operation at the verification points of -0.06MPa, -0.04MPa, and -0.02MPa, check the pressure values of the verified pressure gauge, tap the verified pressure gauge, and record the indicated value after the tap is stabilized.
3. Pressure relief process
Open the vent valve, gradually release the pressure inside the pipeline until it reaches 0, and then the measurement is complete.
III. Precautions
Standardized use
• During verification, it is important to ensure that the tolerance of the standard meter is less than that of the verified meter, in order to ensure accurate and reliable verification results that meet the metrological specifications.
• Operations should follow standard procedures. The ALKB601 portable air pressure pump should be pressurized and depressurized slowly to avoid pressure shock.
• Increase the pressure to the verification point and record the indicated value after the standard gauge value stabilizes. For the verified pressure gauge, tap the gauge case gently after the pressure stabilizes, and take the indicated value after tapping as the accurate reading to ensure accurate recording.
• After the inspection is completed, slowly release the pressure to zero and ensure there is no residual pressure before removing the inspected instrument.
Maintenance and calibration cycle
• Regularly conduct metrological verification on the Precision digital pressure gauge alkc400D (it is recommended to do so once a year) to ensure that the measurement accuracy meets the required standards.
• When the pressure gauge is not in use, the power should be turned off. If it is not used for a long time, it should be charged once every three months.
• If the portable air pressure pump is not to be used for a long time, it should be depressurized before storage. A cloth cover should be placed on top to prevent dust from entering the instrument.
IV. Conclusion
The calibration and inspection of pressure gauges are crucial components in ensuring the smooth operation of industrial production. By adhering to standardized verification procedures, judiciously selecting standard instruments and the equipment under inspection, and rigorously controlling the calibration operations at various stages such as pressure increase, decrease, and vacuum, we can effectively guarantee the accuracy of pressure gauge readings and their reliable performance. Simultaneously, by conducting periodic verification and routine maintenance of standard equipment, and continuously enhancing the standardization of calibration work, we provide a solid foundation for ensuring the compliance and precision of pressure measurement data.
