Table of Contents

Pressure Gauge calibration

Pressure Gauge calibration is comparison of measurement values of a unit under test with those of a more accurate calibrated standard gauge.

Equipment Required

Pressure comparator:-

Pressure comparator is similar to dead weight tester. Which generates pressure to achieve the desired pressure.

Master gauge:-

Digital gauge is used as master gauge to calibrate measuring instruments in ISO 9000 qualified laboratories. P.G.(Pressure Gauge) may offer an accuracy of ±0.1%, depends on the manufacturer.

Gauge Calibration Sheet:-

The calibration sheet is used to note the readings of the pressure gauge compared on the comparator. The example of pressure gauge calibration sheet is given below.

PG Calibration procedure

Check at ambient pressure without connection, gauge value should be zero. If not, adjust the zero screw or pull the pointer using needle puller & put it to 0 values.
Now connect the pressure gauge to pressure calibrator.
Apply pressure till gauge span value & verify pressure gauge maximum pressure value should be same as standard gauge reading if not, correct the indication increase or decrease the sector arm.
Apply pressure 50% of gauge span (for linearity adjustment)
Adjust the length of link after pulling the pointer using puller and place at correct spot (at 50%)
Verify linearity at check points 0%, 25%, 50%, 75% and 100% of full gauge span and fill the calibration sheet.
Repeat these steps until correct value achieved.