The Behavior of the Bourdon Tube under Internal Pressure

It is about one hundred years since the Bourdon tube was produced by Eugene Bourdon, but the studies on it have scarecely been done. Especially; there is no paper which deals with the research on the effects that the manufacturing processes influence on the accuracy and the quality of the Bourdon tube. The authors investigate the relations between many factors of working and the qualities of products, and after due consideration of the working conditions the 0.04% gauge are manufactured. This paper describes the behavior of the Bourdon tube when the internal pressure varies. The results of the experiments are as follows, (1) the experimental formula of sensitivity; Δr/r_??_0.045 P·r·a3/E·b·t3, here Δr; increment of r when the internal pressure increases, 2a; the width of the cross section, 2b; the height of the cross section, r; the radius of the Bourdon tube, t; the thickness of the wall, E; Young's modulus, (2) the changes of hardness on wall of the Bourdon tube when the alternative pressures repeat are obtained. The fracture the under repeated load is the result of the softening effect of the wall-hardness. And the hardness value that the fracture occurs, is five % under when it is compared with the initial hardness.