Pressure gauge calibration is done using dead weight tester.
Before going to the calibration procedures, one must ensure that there is enough fluid in the dead weight tester so that pressure in the tester can transmit properly. Mark the serial number of the gauge in the analysis table.
Steps:
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Mount the test gauge on the dead weight tester.
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Loose the adjusting piston fully to make the piston completely disengaged
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Now weight in the gauge is zero, so connect the needle to the gauge pointing to zero.
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Change the weights in a range. Say 0, 20 , 30, 40 … Mark the weight and corresponding gauge reading in the analysis table.
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Put the weight on the deadweight and tight the adjusting piston until the weight floats freely. Check the gauge reading and note in the analysis table.
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The difference between dead weight and gauge reading is the error.
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If there is an error in readings, then mark some weights on the wall of the gauge.
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Remove the caps and the scale on the gauge, so that we can clearly see the bourdon tube.
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Connect the needle to the gauge again and do the weight test again for the marked points.
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Loose the screw in the adjustable link and correct the needle mark to the actual position, which is already marked on the gauge. Then redo the screw again.
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Fix the scale again to the gauge. Repeat the dead weight test for confirmation.
