Bourdon tube pressure gauges are the most regularly used mechanical pressure measuring instruments. Their pressure element is often known 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 having an oval cross-section.
ไดอะแฟรม ซีล 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 increase the radius of the c-shaped tube. As a result, 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 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 can be displayed. For higher pressures, helical or spiral-type Bourdon tubes are used. According to the geometry, material and material thickness, pressures around 7,000 bar can be realised. According to the requirement, the pressure elements are constructed of copper alloys, stainless steels or special materials such as Monel.
Note
Further information on Bourdon tube pressure gauge s can be found on the WIKA website.