Study of a Bourdon Tube-Hall Sensor Based Non-Contact Smart Pressure Transmitter

In every process industry, it is essential to accurately measure the pressure at a specific point within a fluid (liquid or gas). There are various conventional pressure sensors available among which the Bourdon tube is the most popular one due to its simple design and high reliability. However, the Bourdon gauge is a local indication instrument, and various techniques are utilized for remote indication of gauge pressure. In this paper, we suggest a straightforward non-contact smart pressure transmitter that employs a Bourdon tube in conjunction with a Hall sensor. This method involves mounting a Hall sensor integrated circuit (IC) on the non-magnetic aluminium housing of a Bourdon gauge, with a small disclike hard magnet securely fastened to the flexible end of the Bourdon tube. The Bourdon tube's flexible end, accompanied by the hard magnet, shifts towards the Hall sensor as the fluid pressure within it rises. This causes a boost in the power of the magnetic field detected by the Hall sensor, which raises the pressure and amplifies the electrical output of the Hall sensor. It also produces a higher signal from the transmitter circuit, which consists of an instrumentation amplifier, a differential amplifier, and an appropriate signal conditioner. The transmitter circuit is interfaced with an Arduino microcontroller board to store or display the measured data in a local computer. This data can be transmitted to a remote computer or cloud for access by multiple users from any location. The operation of the proposed pressure transmitter is theoretically explained and experimentally verified. The theoretical equations closely correspond to the experimental static characteristic curves of the transmitter, exhibiting good repeatability.