Bourdon tube pressure gauge ? operating principle

Bourdon tube pressure gauges will be the most regularly used mechanical pressure measuring instruments. Their pressure element is frequently referred to as a Bourdon tube: The French engineer Eug�ne Bourdon made use of this functional principle in the center of the 19th century. It really is predicated on an elastic spring, a c-shaped, bent tube having an oval cross-section.
The result of pressure on a Bourdon tube
Once the internal space of the Bourdon tube is pressurised, the cross-section is thus altered towards a circular shape. The hoop stresses which are created in this process raise the radius of the c-shaped tube. Therefore, the finish of the tube moves by around several millimetres. This deflection is really a measure of the pressure. It really is transferred to a movement, which turns the linear deflection right into a rotary movement and, via a pointer, makes this visible on a scale.
Bourdon tube variants
With the c-shaped bent Bourdon tubes, pressures up to 60 bar could be displayed. For Weak , helical or spiral-type Bourdon tubes are used. With respect to the geometry, material and material thickness, pressures up to 7,000 bar can be realised. Based on the requirement, the pressure elements are constructed of copper alloys, stainless steels or special materials such as for example Monel.
Note
Further information on Bourdon tube pressure gauges can be found on the WIKA website.

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