# What is pressure calibration? State stepwise procedure to test the accuracy of pressure gauge with dead weight tester.

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What is pressure calibration? State stepwise procedure to test the accuracy of pressure gauge with dead weight tester.

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Pressure Calibration: It is the process of adjusting the instrument’s output signal to match a known range of pressures. Calibration of a given pressure gauge can be done with the help of dead weight pressure gauge tester. In this method, the output of the given faulty or uncalibrated pressure gauge is compared with pre calibrated dead weight pressure and corrected.

Diagram For Dead weight Pressure gauge tester:

Stepwise procedure:

• The handle of the dead weight tester is fully drawn out and the oil is allowed to enter in the cylinder (i.e. gauge and piston)

• A known accurate weight is placed on the platform. The area of the piston is also known; hence we can calculate the pressure.

• Now the handle is turned in clockwise direction so that the pressure will buildup on the gauge side as well as platform side.

• The pressure is increased by rotating the handle clockwise until enough pressure is developed inside the cylinder to lift the platform with weights placed on it and it floats freely.

• The procedure is repeated for different weights (increase weights in steps). In the same way most of the pressure gauges are calibrated against dead weight testers.

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Explanation- The handle is fully drawn out and the oil is allowed to enter in the cylinder (i.e. gauge and piston). A known accurate weight is placed on the platform. The area of piston is also known; hence we can calculate the pressure. Now the handle is turn to press in clockwise direction so that the pressure will buildup on the gauge side as well as platform side. Increase the pressure by rotating the handle clockwise until enough pressure is developed inside the cylinder and lifts the platform with weights placed on it and it floats freely within the limit stops. Repeat the same procedure for different weights. In the same way most of the pressure gauge are calibrated against dead weight testers. An error in dead weight tester is less than 0.1% in order to reduce the friction between the piston and cylinder, the piston is gradually rotated while a reading being taken