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civil engineering-->>To Calibrate a Pressure Gauge Using a Dead Weight Pressure Gauge Calibrator

To Calibrate a Pressure Gauge Using a Dead Weight Pressure Gauge Calibrator


Apparatus

  • Dead weight pressure gauge calibrator having the following main components,
  • Cylinder
  • Weights
  • Leveling screws
  • Spirit level
  • Cylinder inlet
  • A gauge to be calibrated
  • Hydraulic bench

Concepts:

Calibration of guage:

To compare the values of an instrument with that of the standard ones is known as calibration of that instrument.

Pressure gauges:

The instruments with the help of which we measure the pressure are called as the pressure gauges.

Absolute Pressure:

The pressure measured with reference to absolute zero is called as absolute pressure.

Gauge pressure:

The pressure measured with the atmospheric pressure is called as gauge pressure.
Pressure Guage















Vacuum pressure:

Negative gauge pressure is known as vacuum pressure.

Atmospheric pressure:

The pressure exerted by the atmosphere above us is known as the atmospheric pressure.
Its standard values are given below.
1 atm =14.7psi
101300Pa
0.1Mpa
76cm of Hg
760 mm of Hg
1.01 bar
34’ of water

Procedure:

  • I placed the pressure gauge and calibrate assembly on bench top.
  • I connected the inlet tube to the gauge manifold.
  • A length of tube was connected to the calibrator drain and laid into the channel to prevent spillage of water on the bench top.
  • The calibrator was leveled by the adjusting feel whilst observing the spirit level.
  • I removed the piston and accurately determined its mass.
  • I closed the control valve of the bench and open both cocks then I operated the pump starter and also open the control valve and admitted the water to the cylinder.
  • After removal of air bubbles from the tube, I closed the cock along with flow control valve and switched of the pump.
  • I noted the gauge readings corresponding to the piston mass of .5 kg.
  • Then I added .5 kg mass each time and noted the corresponding gauge readings.
  • Then I find out the Absolute gauge error by the following formula.
  • Absolute gauge error = Pressure in cylinder – Gauge reading
  • Then I find out the %age gauge error by the following formula.
  • %Age gauge error = Absolute gauge error *100 / Pressure in cylinder
  • Then I plotted a graph between %age gauge error and pressure in cylinder.

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