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.
