Define absolute pressure and gauge pressure. State the different units for pressure measurement.
Definition: Absolute pressure: Absolute pressure is defined as actual total pressure including atmospheric pressure actin On a surface. PAbsolute= PAtmospheric + PGauge Gauge pressure: Gauge pressure is defined as the difference between absolute pressure and atmospheric pressure. Gauge pressure= PAbsolute – Patmospheric
Units for pressure measurement. Pascal ( Newtons per meter square) with various prefixes Pounds per square inch atmosphere (used for comparisons to sea level) inches of mercury (aviation, altimeter setting) mm of mercury column (blood pressure) inches of water Barmillibar (weather) Torr