Pressure is defined as the amount of force applied to the surface or distributed over it and is measured as force per unit area.
Pressure may be measured in either British or Metric unit. In British unit, a pressure is measured in the pound (of force) per square inch (of the area). In Metric unit it is measured in newtons (of force) per square meter (of the area).
In engineering, it is most commonly expressed in terms of pound per square inch (PSI). The atmospheric pressure is approximately 14.696 PSI or 1 kg/cm². pressure can be also measured in terms of liquid columns, in which the atmospheric pressure will be equal to 760mm (29.92 inches).
1. What is absolute pressure?
Absolute pressure is total pressure present in system.
Absolute pressure = gauge pressure + atmospheric pressure
2. What is gauge pressure?
Gauge pressure is above the atmospheric pressure.
Most pressure gauges used atmospheric pressure (14.7psi) as a zero point, the indicate a pressure of zero psi at the surface of a liquid even though the pressure is actually 14.7psi (1 kg/cm²).
A gauge that indicates 0 at atmospheric pressure measured the difference between actual and atmospheric pressure. This difference called gauge pressure.
3. What is absolute zero pressure?
Absolute zero = 760 mm of Hg
4. What is a maximum vacuum?
The maximum vacuum = 760 mm of
5. What is a vacuum?
Any pressure below atmospheric pressure is a vacuum.
1. What is a primary element for measuring pressure?
Most pressure instrument measures a difference between two pressures. One usually being that of the atmospheric. The primary elements are
1. Bourdon tube
2. Diaphragm
3. Capsule
4. Bellows
5. Pressure spring
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