12-10-2012, 04:18 PM
CALIBRATION OF PRESSURE GAUGE
CALIBRATION OF PRESSURE GAUGE.docx (Size: 53.37 KB / Downloads: 34)
THEORY:
The principle used in dead weight tester is that the pressure is equal to force by area. The dead Weight tester apparatus consists of the following parts. A chamber which is filled with oil free of impurities. A piston-cylinder combination is fitted above the chamber. The top portion of the piston is attached with a platform to carry weights. A plunger with a handle has been provided to vary the pressure of oil in the chamber. The pressure gauge to be tested is fitted at an appropriate place. By keeping the area as small as possible high pressure can be developed using less weight. When the pressure develops inside the tester increases, the position will raise and float freely which means that pressure inside is equal to downward force exerted by weight. Once the piston floats freely, the pressure inside will not increase even if the spindle is rotated further.
PROCEDURE:
1. Keep a standard weight of 0.5 Kg/Cm2 on the piston plat form.
2. Apply pressure to the chamber containing oil by rotating the handle in the anti clock wise direction.
3. Continue rotating the handle until piston-carrying weight shows a red line.
4. Now note down the reading in the pressure gauge.
5. Repeat the same procedure by increasing the weights on the platform in steps of 0.5 Kg/Cm2 and note down the reading shown by the gauge.
6. Draw the graphs between
i. Applied Pressure Vs indicated Pressure.
ii. Applied Pressure Vs Error.