types of pressure measurements
TRANSCRIPT
TYPES OF
PRESSURE MEASUREMENTS
The relationships between gauge and absolute pressure are critical 2
Pressure Line
0 PSIA 14.7 PSIA
100 PSIA 114.7 PSIAVacuum Range
14.7 PSIV-1 ATM0 “ Hg
0 mB/hPa0 Torr A
0 PSIVATM
29.92 "Hg1013 mB / hPa
760 Torr A
Atmospheric Pressure-14.7 PSIG 0 PSIG
85.3 PSIG 100 PSIG
85.3 PSIC
Absolute Pressure
Definition: Pressure measured relative to full vacuum (refers to a true zero reference)
Units of Measure:Pounds per square inch absolute or (PSIA)
Applications: best used in applications that require higher accuracies over large temperature range or for comparative studies at different elevations
Atmospheric Pressure
Definition: Pressure of the atmosphere at the earth’s surface. At sea level this pressure is not constant (it varies with the weather) but averages around 100 kilopascals (kP). One atmosphere is also approximately the ambient pressure at sea level and is equal to 14.7 PSIA
Units of Measure:pounds per square inch (psi), atmospheres (atm), mb, hPa can measure ambient pressure in other circumstances
Applications: remote weather stations, test stand reference pressure
Barometric Pressure
Definition: The measure of atmospheric pressure
Units of Measure:Often measured in millibars, in Hg (inches of mercury), or hector pascalsIn other circumstances ambient pressure may be measured in pounds per square inch (PSIA)
Applications: airports, AWOS systems, humidity measurements, data buoys
Compound Pressure
Definition: Pressure measured from full vacuum (-14.7 PSIV) through atmospheric pressure to a positive gauge pressure, being referenced to current atmospheric pressure
Units of Measure:pounds per square inch compound (PSIC)
Applications: autoclaves, instrument sterilization, pumps
Differential Pressure
Definition: Pressure measured relative from one pressure to another
Units of Measure:pounds per square inch differential or (PSID)
Applications: filter status, static pressure, chillers, sealed tank
Gauge Pressure
Definition: A form of atmospheric pressure measured relative to ambient atmospheric pressure
Units of Measure:pounds per square inch (PSIG)
Applications: measuring pressure in vented tank (link to app note), pumps, compressors, test stands
Vacuum Pressure
Definition: Generally refers to pressures below atmospheric pressure
Units of Measure:pounds per square inch vacuum (PSIV) or 0-30”Hg
Applications: semiconductor fabs, plasma sterilizers, vacuum packaging