What Is an Absolute Pressure Gauge?
Absolute pressure gauges are a type of pressure gauges that measures the pressure applied to an object.
There are two types of pressure gauges: those that measure “absolute pressure” and those that measure “gauge pressure,” and absolute pressure gauges, as the name suggests, can measure absolute pressure.
Normally, when measuring pressure, atmospheric pressure, which is always applied in daily life, is used as the zero standard and the difference from atmospheric pressure is measured as “gauge pressure.” Absolute pressure gauges, however, measure pressure with a vacuum state as the zero standard and obtain a value different from gauge pressure.
Uses of Absolute Pressure Gauges
The relationship between absolute pressure and gauge pressure is as follows:
Absolute pressure – Atmospheric pressure = Gauge Pressure
Atmospheric pressure is the pressure that is always applied in everyday life and is the weight of air. Atmospheric pressure is highest at sea level and decreases as elevation increases.
Absolute pressure gauges are used to measure the pressure inside vacuum pumps and sealed spaces, because they can measure the pressure applied to an object itself without taking into account the atmospheric pressure values that vary from place to place.
Principle of Absolute Pressure Gauges
Basically, when measuring pressure, the side to which the pressure to be measured is applied is the base side, and the difference from the pressure on the back side is quantified. Although the measurement method is the same, there is a difference in the detection method used to detect each pressure.
Gauge pressure gauges measure the difference in pressure from atmospheric pressure, so the part that detects the pressure on the rear side is either open and uses the atmospheric pressure in place, or it detects atmospheric pressure in a pattern that encloses atmospheric pressure and produces a differential pressure.
Absolute pressure gauges, on the other hand, detect vacuum pressure by using a vacuum chamber for the part that detects pressure on the rear side and outputs the difference between the vacuum pressure and the absolute pressure.
In the past, pressure gauges were often displayed in memory, but recently, more and more are being displayed digitally to measure pressure with higher accuracy.