Differential pressure gauges working principle

Differential pressure gauges measure the difference between two pressures. They are suitable for the monitoring of filter contamination, for level measurement in closed vessels, for over pressure measurement in clean rooms, for flow measurement of gaseous and liquid media and for the control of pumping plants.

In differential pressure gauges, different pressure elements and tube forms are used (diaphragm element, capsule element, Bourdon tube, etc.). This enables scale ranges of 0 … 0.5 mbar up to 0 … 1,000 bar to be covered, with a very high single and dual-sided and also bidirectional over pressure safety up to 400 bar.

Function of a differential pressure gauge

The media chambers of a differential pressure gauge are separated from each other by the pressure element. If the two pressures being measured are the same, there is no movement through the pressure element and no pressure is indicated. As soon as the two measured values are different to each other, thus one of the pressures is higher or lower, then a differential pressure will be indicated. The transmission of the pressure element displacement and the indication of the pressure is achieved via a mechanical movement.

bellows-differential gauge


Differential pressure gauge is largely used in domestic and industrial applications. It is often the basis of other measurements such as flow, level, density, viscosity and even temperature. The most common being level and flow.

DP Flow rate measurement  is one of the most common applications for differential pressure transmitters. By measuring the difference in fluid pressure  while the fluid flows through a pipe it is possible to calculate the flow rate.

The secondary element of the flow meter is the differential pressure gauge. It is designed to measure the differential pressure produced by the primary element as accurately as possible. In particular it is important that the differential pressure measurement is not affected by changes in the fluid pressure, temperature or other properties such as ambient temperature.

Leave a Comment

Your email address will not be published. Required fields are marked *