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 is based 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 which are created in this technique increase the radius of the c-shaped tube. Due to this fact, the end of the tube moves by around two or three millimetres. This deflection is a measure of the pressure. It is used in 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 Frenzied , helical or spiral-type Bourdon tubes are used. Depending on geometry, material and material thickness, pressures around 7,000 bar can be realised. With regards to the requirement, the pressure elements are constructed with 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.

Leave a Reply