Bourdon tube pressure gauge ? operating principle

Bourdon tube pressure gauges are 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 used this functional principle in the middle 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 raise the radius of the c-shaped tube. Subsequently, the end of the tube moves by around two or three millimetres. This deflection is really a way of measuring the pressure. It really 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 could be displayed. For Latest , 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. According to the requirement, the pressure elements are constructed with copper alloys, stainless steels or special materials such as Monel.
Note
Further information on Bourdon tube pressure gauges can be found on the WIKA website.

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