Bourdon tube pressure gauge ? operating principle

Bourdon tube pressure gauges will be the most regularly used mechanical pressure measuring instruments. Their pressure element is often known 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 with an oval cross-section.
The effect 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 that are created in this technique increase the radius of the c-shaped tube. Therefore, the finish of the tube moves by around two or three millimetres. This deflection is a measure of the pressure. Uplifted is transferred to a movement, which turns the linear deflection into a rotary movement and, with a pointer, makes this visible on a scale.
Bourdon tube variants
With the c-shaped bent Bourdon tubes, pressures up to 60 bar can be displayed. For higher pressures, helical or spiral-type Bourdon tubes are employed. Depending on the geometry, material and material thickness, pressures around 7,000 bar could be realised. With regards to the requirement, the pressure elements are constructed of copper alloys, stainless steels or special materials such as Monel.
Note
More info on Bourdon tube pressure gauges can be found on the WIKA website.

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