Are your costs running high for outsourcing analogue pressure gauge calibration to comply with your ISO9000 quality system approval? Then maybe it is time to invest in your own pressure calibrator.
You will dramatically reduce your annual re-calibration charges and there will be no need to maintain a buffer stock of dial pressure gauges to keep manufacturing processes running while other production critical pressure instruments are sent away for their annual calibration.
If all analogue pressure gauges are fitted with a three way isolation valve they can be calibrated in-situ by teeing into the pressure gauge with a quick release pressure connection and isolating the device under test. You can then apply pressures with a hand-pump to the pressure gauge and calibrate at each set-point.
When setting each pressure calibration point use the cardinal points (division markers) on the pressure gauge under test rather than setting the pressure to the exact point on the digital display of the pressure calibrator. This way it will be easier to read the error from the digital display which has a much higher display resolution than the pressure gauge under test.