An approach to design a Bourdon tube pressure transmitter for remote measurement

Abstract

C-type Bourdon tube is most common and popular pressure measuring instrument in process industry. Due to simple and rugged low cost construction, Bourdon tube is still used for local pressure monitoring system. The key challenge of this elastic-mechanical pressure sensor is its non electrical output. In this paper, a secondary element, Linear Variable Differential Transformer (LVDT) is attached with the C-type Bourdon tube which act as primary sensing element to get electric signal as output. The sealed tip of the Bourdon tube is mechanically coupled with the core of the LVDT. The applied input pressure causes defection of the tip of the Bourdon tube. This deflection is sensed by LVDT and produce electric signal proportional to the applied pressure. The signal after conditioning converted to 4-20mA DC signal for industrial compatibility. This current signals can drive loop powered digital indicator, universal controller and remote telemetry system. This modified pressure measurement system shows the higher accuracy with a dynamic range of 15 psig. The experimental data follows good static characteristics with acceptable linearity and repeatability.