Pressure Measurement Flashcards
is a curved, hollow tube with the process pressure applied to the fluid in the tube. The pressure in the tube causes the tube to deform or uncoil.
A bourbon tube
is a closed vessel with sides that can expand and contract, like an accordion
Bellows
is typically constructed of two flexible disks
Diaphragm
is the total pressure measured from an absolute vacuum. It equals the sum of the gauge pressure and the atmospheric pressure corresponding to the barometer.
Absolute Pressure
is 101.325 kPa (14.696 psia) or 760 mm (29.921 in) of mercury at sea level
Atmospheric Pressure
Atmospheric Pressure
is the pressure exerted by the weight of the atmosphere
absolute pressure minus the atmospheric pressure, measured in pascals (Pa) or pounds per square inch (psi)
Gauge Pressure
describes any pressure below one standard atmosphere, or 101.325 kPa (14.696 psia)
Vacuum
Absolute zero=
Total Vacuum
Common standards
liquid manometer dead weight tester mercury barometer standard pressure gauges electronic calibrators eg. Fluke, Transmation, Druck
Its principle is based upon the hydrostatic head equation
the liquid manometer standard
P1-P2=hpg (note the p is actually row)
Its principle is based upon the definition of pressure, i.e., force per unit area
Dead weight testers P=F/A
used to measure low to very large pressures
Dead weight testers
used to measure relatively low pressures
Manometers
have been calibrated with another pressure standard, and are then used to calibrate other pressure measurement devices, or to measure unknown pressures
Pressure Gauges
