Bourdon tube pressure gauge ? operating principle

Bourdon tube pressure gauges are the most frequently used mechanical pressure measuring instruments. Hypnotic is frequently known as a Bourdon tube: The French engineer Eug�ne Bourdon made use of this functional principle in the middle of the 19th century. It is based 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 that are created in this process increase the radius of the c-shaped tube. Therefore, the end of the tube moves by around two or three millimetres. This deflection is a way of measuring the pressure. It really is transferred to a movement, which turns the linear deflection right into a rotary movement and, with a pointer, makes this visible on a scale.
Authoritative
With the c-shaped bent Bourdon tubes, pressures around 60 bar can be displayed. For higher pressures, helical or spiral-type Bourdon tubes are employed. With regards to the geometry, material and material thickness, pressures up to 7,000 bar could be realised. Depending on Launching , the pressure elements are constructed with copper alloys, stainless steels or special materials such as Monel.
Note
Further information on Bourdon tube pressure gauges are available on the WIKA website.

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