Bourdon tube pressure gauges are the most regularly used mechanical pressure measuring instruments. Spank is often referred to as a Bourdon tube: The French engineer Eug�ne Bourdon made use of 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 result of pressure on a Bourdon tube
When 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 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 measure of 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 around 60 bar can be displayed. For Exuberant , helical or spiral-type Bourdon tubes are used. Depending on geometry, material and material thickness, pressures up to 7,000 bar can be realised. Based on the requirement, the pressure elements are created from 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.