# ABSOLUTE ,GAUGE ,& VACUUM PRESSURE

ABSOLUTE ,GAUGE ,& VACUUM PRESSURE

The pressure on a fluid is measured in two different systems . In one system it is measured above & absolute zero or complete vacuum and it is called the absolute pressure and in other system , pressure is measured above the atmospheric pressure and it is called gauge pressure . Thus

1. Absolute Pressure - is defined as the pressure which it measured with reference to absolute vacuum pressure.

2. Gauge Pressure - is defined as the pressure which is measured with the help of pressure measuring instrument in which the atmospheric pressure is taken as datum . The atmospheric pressure on the scale is marked as zero .

3. Vacuum Pressure - is defined as the pressure below the atmospheric pressure .

The relation between the absolute pressure , gauge pressure , vacuum pressure are shown in mathematically ;
1. Absolute pressure = Atmospheric pressure + Gauge pressure
2. Vacuum pressure = Atmospheric pressure - Absolute pressure