bourdon gage

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LAB # 2Calibration of

Pressure GaugeFLUID MECHANICS LABINSTRUCTOR: HUSNAIN AHMED

9TH SEPTEMBER, 2014


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Content

BourdonGauge

DeadWeight

Calibrator

ExperimInstructio


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INTRODUCTION

Bourdon tube gauge is device to measure andrepresent applied pressure.

SENSING ELEMENT:

Consists of a twisted or curved metal tube.

The tube is constructed from a thin walled tube ofnon circular cross section

REPRESENTATIVE ELEMENT:

A needle on a Gauge.


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PARTS:


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WORKING PRINCIPLE

The bourdon principle believes that aflattened tube will reform or growconsiderably in the cross sectionalaspect when a pressure is applied. Thischange can be represented by a needleon a gauge.


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PROS & CONS

PROS:o Less Expansiveo Portableo Easy to useo No leveling required

CONS:o Static Measurement onlyo Lower accuracy.


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INTRODUCTION

A dead weight tester apparatus uses knowntraceable weights to apply pressure to a fluid forchecking the accuracy of readings from a pressuregauge.


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PARTSPiston

The Dead Weight Calibrator accessory comprises a precision

ground piston and cylinder.

WeightsWeights may be added to the piston so that a number ofpredetermined pressures may be set up within the cylinder.

BaseboardThe cylinder is mounted on a baseboard which is supported on

leveling screws and fitted with a spirit level.

Gauge ConnectionThe gauge under test is linked to the cylinder connection by aflexible tube.


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WORKING A pressure gauge could be calibrated by mounting a closed vessel

with a piston at one end. (Such a vessel is called a dead-weighttester).

Placing a weight on the piston produces a known pressure in the vessel equal to the weight divided by the piston area.

After applying a series of weights and measuring the correspondingoutput value of the pressure gauge you can plot the relationshipbetween the gauge reading and added weights.


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CALIBRATION OFPRESSURE GAUGE

EXPERIMENT 2


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OBJECTIVE

To calibrate a Bourdon type pressure gauge andto determine the gauge errors.

To determine the measurement errors in thereference pressure source used for calibration


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APPARATUS

Accurate weights

Bourdon Tube PressureGauge

Dead Weight Tester

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APPARATUS DEMONSTRATION

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Related Theory A measurable reference pressure, P is generated due to the use of piston and weights with the cylinder:

P=F/A (Pascals)F=Mg

A= d2/4 F is the force applied to the liquid in calibrator cylinder M is the total mass including piston mass A is area of piston


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EQUIPMENT SETUP

Note the weight of the piston (0.5kg) and individual calibration masses before setting the equipment.

Place the dead weight calibrator bench top and ensure that the base ishorizontal by adjusting the base using spirit level. This is necessary toensure the vertical transfer of the applied load and free rotation of

piston.

Attach the flexible tube from the base of the cylinder to the base of theBourdon gauge.

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PROCEDURE


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PROCEDUREObserve the Pressure gauge unit setup.Be sure all hoses are attached securelyto the Bourdon gauge.

Record the gauge reading ( KN/m2) forthe unloaded piston, which correspondsto a total mass.

Place the given dead weight (0.5 Kg)one by one and record the reading ofthe gauge.

To prevent the piston from sticking,rotate the piston gently as each mass isadded, so that the friction in the pistoncan be reduced.

Tabulate data in table & Plot thecalibration curve 21


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TO DO !

ASSIGNMENT SUBMISSION (FLUID MECHANICS APPLICATION)

TASK 1: LAYOUT SUBMISSION

PERFORM EXPERIMENT

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bourdon gage

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