Ordinary cylinder pressure gauges are mostly made by using the principle of Burton tube. I wonder how the Burton tube works. Who knows how to help me solve it? Thank you.

Bourdon tube (Bourdon? Tubes) is a kind of elastic sensitive element which uses the bending change or torsional deformation of the tube to measure the pressure, also known as spring tube. One end of the Bourdon tube is fixed, the other end is movable, and its cross-sectional shape is oval or flat. The tube with non-circular cross section gradually expands into a circle under the action of its internal pressure, and at this time, the movable end produces a displacement related to the pressure. The movable end drives the pointer to indicate the pressure. The most commonly used Bourdon tube is C-type, in addition to spiral type, C-type combination, twisted type and other types (see figure). The material of Bourdon tube is copper-based or iron-based alloy. Compared with other pressure sensitive elements, it has lower sensitivity, and is often used to measure larger pressure, and is often used in combination with other elastic elements. 1852 E. Boden obtained the patent right of Boden tube. Up to now, the spring tube is still widely used in many instruments, especially in the measurement of pressure and force.