Definition - What does Absolute Pressure mean?
Absolute Pressure is defined as a vacuum that has zero pressure. This pressure is considered as a part of zero reference trinity which includes Gauge Pressure, Differential Pressure and Absolute Pressure. The cases in which this pressure is used include the readings of atmospheric pressure in which air pressure, boiling point of the water or mean pressure of the sea level can be determined. Measurements of the deep vacuum pressure in which the absolute or the perfect readings are required is also another instance where Absolute Pressure is used because scientists deal with the near-total vacuum.
Petropedia explains Absolute Pressure
Absolute Pressure is different from the gauge pressure and differential pressure as they are measured corresponding to absolute zero pressure which is pressure that takes place at absolute vacuum. Gauge pressure is referred to the difference in pressure between the system, which is the absolute pressure, and surrounding atmosphere. On the other hand, differential pressure is more complicated than absolute and gauge pressures as it simply measures the difference between these two pressures.
Absolute Pressure sensor can be produced by sealing a high vacuum trailing the sensing diaphragm. When the connection of the absolute pressure transmitter is left open to air, it reads actual barometric pressure. It can be differentiated from most of the gauges, like the ones which are used to measure the tire pressure where gauges are measured to consider air pressure.