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 is predicated on an elastic spring, a c-shaped, bent tube having an oval cross-section.
The effect 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. Contrary which are created in this process increase the radius of the c-shaped tube. As a result, the finish 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 right 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 higher pressures, helical or spiral-type Bourdon tubes are employed. According to Instant Savings , material and material thickness, pressures around 7,000 bar can be realised. With respect to the requirement, the pressure elements are made of copper alloys, stainless steels or special materials such as for example Monel.
Note
Embarrassing on Bourdon tube pressure gauges can be found on the WIKA website.