Bourdon tube pressure gauges are the most frequently 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 middle of the 19th century. It really is predicated 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 which are created in this process raise the radius of the c-shaped tube. Due to this fact, the finish of the tube moves by around two or three millimetres. This deflection is really a way of measuring the pressure. It really is used in a movement, which turns the linear deflection right into a rotary movement and, via 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 Cancel Anytime , helical or spiral-type Bourdon tubes are used. With respect to the geometry, material and material thickness, pressures around 7,000 bar could be realised. According to the requirement, the pressure elements are made of copper alloys, stainless steels or special materials such as Monel.
Note
More info on Bourdon tube pressure gauges are available on the WIKA website.