Bourdon tube

It consists of seamless metal tubing having elliptical cross section. The tube is enclosed in a socket which contains pressure inlet. One end of the tube is sealed and the other end is open to apply the pressure. The sealed end is free to move and called as tip. According to the application, the material can be changed. In general, the materials can be changed. In general, the materials used are bronze, beryllium, copper, stainless steel, chrome molybdenum etc.
For static and slowly varying pressure measurement over a wide range, C shaped bourdon tube is preferred. When pressure is applied at inlet of socket, tip deflects. There is an arrangement for converting this linear displacement into circular displacement. The pinion gear system is used for this conversion. The pointer is mixed on the gear which shows the deflection. A calibrated scale is used for giving read out.