[161] Bourdon-tube pressure gauge
Most pressure gauges
operate on the principle of a Bourdon tube. When hydraulic fluid
flows into the tube, an identical pressure is produced
throughout. Due to the difference in area between the outer and
inner curved surfaces, the tube is bent. This movement is
transferred to a pointer.
This type of gauge is not protected against overload. A cushioning restrictor must be installed in the inlet connection prevent pressure surges from damaging the tube.