Pressure Measurement

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Pressure Measurement
Many text define the force per unit area exerted
by a fluid on its containing wall as a pressure
and the force per unit area that arises as a
result of a strain in solids as a stress. The
units of measure are the same and the strain
measurement is often used to infer the pressure.
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Absolute Pressure Absolute force per unit
area kPa, psia, in H2O, mm Hg, ...
Gage Pressure Difference between absolute
pressure and local atmospheric pressure kPa,
psig, in H2O, mm Hg, .
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Vacuum When below atmospheric pressure,
difference between and absolute pressure and
atmospheric pressure kPa in H20, in Hg
Note Vacuum is normally a gage measurement.
May sometimes be stated as an absolute
pressure, especially in SI system
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Absolute pressure is 40 kPa
40 kPa absolute
40 kPa vacuum
Absolute pressure is 101.3 kPa - 40 kPa 61.3
kPa
(Assuming local atmospheric pressure is 101.3
kPa)
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Bourdon Gage
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Application Range