Pressure definition and Types, Units
Pressure is probably one of the most commonly measured variables in the power plant. It includes the measurement of steam pressure; feed water pressure, condenser pressure, lubricating oil pressure and many more. Pressure is actually the measurement of force acting on area of surface. We could represent this as
The units of measurement are either in pounds per square inch (PSI) in British units or Pascals (Pa) in metric. As one PSI is approximately 7000 Pa, we often use kPa and MPa as units of pressure.
Pressure Measurement :
This module will examine the theory and operation of pressure detectors (bourdon tubes, diaphragms, bellows, forced balance and variable capacitance). It also covers the variables of an operating environment (pressure, temperature) and the possible modes of failure.
Difference between absolute pressure and gauge pressure
What is gauge pressure.
The pressure of a system above the atmospheric pressure is called gauge pressure. Gauge pressure can calculated if the absolute and atmospheric pressures are known by using the
Formula: Pgauge = Pabs – Patm
What is absolute pressure
Absolute pressure is a pressure that is relative to the zero pressure in the empty, air-free space of the universe. This reference pressure is the ideal or absolute vacuum.