Anemometric Type Flow Transmitter Using Transistor as a Primary Sensor

Abstract

In this paper, an anemometric type flow meter has been designed and developed using a transistor as a flow sensor. The heat is dissipated from the surface of the p–n diode created by short circuiting the emitter and base terminal of the transistor CL100B causing the drop in the temperature with respect to the fluid velocity and it is utilized to measure the flow rate of the fluid across the pipeline section. Two identical sets of transistor acting like p–n diodes are used, the first diode senses the fluid velocity and produces an inconstant voltage and the other is in contact with the stagnated fluid produces a constant voltage. In this paper, the temperature effect is easily compensated by taking the difference in the output of diodes. The difference between the output voltages of the identical transducer only depends on the flow rate. The transducer design and its theoretical characteristic equation and graphs have been derived and discussed in this paper. The proposed transducer has a low cost with good linearity, accuracy, and repeatability.