ENGLISH
CLASSIFICATION OF PRESSURE MEASUREMENTS
Pressure measurements are relative and therefore refer to a reference pressure. There are four types of pressure measurement which enable the reference pressure to be defined immediately.
-Absolute pressure (A) – Pressure with respect to absolute zero, the ideal vacuum reference; the pressure measured is always higher than the reference pressure.
-Gauge (G) – Pressure measured with respect to atmospheric pressure, environment pressure is the reference; the pressure measured is always higher than the reference pressure.
-Vacuum (V) – Pressure with reference to atmospheric pressure, environment pressure is the reference; the pressure measured is always lower than the reference pressure.
-Differential pressure (D) – Pressure measured with respect to any reference pressure; the pres- sure measured may be higher or lower than the reference pressure.
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Atmospheric pressure
VACUUM
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Vacuum |
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Absolute pressure A |
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The case G is similar to the case D |
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where the reference P = atmospheric P |
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