Design and implementation of density sensor with flow rate as disturbance

In distillation process, density sensor that can overcome the flow rate is very important. This paper represents design and implementation of density sensor with flow rate as a disturbance. The fluid density experiments were carried out using several mixtures of alcohol and water that flew in various percentages. In this design, the density of the fluid is affected by the distance, the height displacement of the hydrometer is measured by the ultrasonic, and the ultrasonic oscillations are ± 1.5 mm which was caused by echo characteristics of the ultrasonic sensor. The problem has been solved with pulse-echo mode with 500 sampling data and 1 ms of sampling time, hence the ultrasonic reading is steady. When the height displacement is greater, the alcohol concentration in the water is higher. The correlation between the height displacements to concentration is non-linear. Various methods of relation model from a distance to concentration have been shown and compared. The best model was acquired by using power equation with a Root-Mean-Square-Error (RMSE), and the result was 2.945. The volume flow rate characteristic has been studied and considered in order to eliminate disruption to concentration readings. The Linear model approach was applied to avoid the influence of the volume flow rate with Root-Mean-Square-Error (RMSE), and the result was 1.095. Minimum flow rate is 0.2 L/m, and maximum flow rate is 0.75 L/m.