Development and implementation of a mass flow monitoring system of granular materials in a drop tube using a capacitance sensor

Ranjbari, Salman; Maleki, Mohammad Reza; Mohammadi, Farzad; Khodaei, Jalal; Mollazade, Kaveh

doi:10.22034/jrmam.2025.14290.656

Development and implementation of a mass flow monitoring system of granular materials in a drop tube using a capacitance sensor

Document Type : Original Article

Authors

salman ranjbari ¹

Mohammad Reza Maleki ¹

farzad mohammadi ²

Jalal Khodaei ¹

Kaveh Mollazade ¹

¹ Department of Biosystems Engineering, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran

² Department of Agricultural Machinery Engineering, Faculty of Agricultural, University of Tehran, Karaj, Iran.

10.22034/jrmam.2025.14290.656

Abstract

Measuring the seed and fertilizer mass flow rate in drill delivery tubes is an essential tool for real-time monitoring of the application rates. In the present study, a non-contact capacitance measuring system was implemented to monitor the granular discharge rate in seed and fertilizer applicators. The set-up consisted of a fluted-roller feeding mechanism and the capacitance measuring system incorporated in the discharge tube. The set-up was mounted on a custom-built vibratory stand to simulate the field condition during the measurement. Then, triple super phosphate, wheat, and alfalfa granular discharge rates were measured over 30 s intervals in both static and dynamic conditions from 3.42±1.22 to 19.3±0.95 g/s in 5 rates, from 2.55±0.23 to 19.02±0.86 g/s in 8 rates, and from 0.42±0.02 to 1.6±0.08 g/s in 7 rates, respectively. The results revealed that the mass flow was effectively correlated with sensor signals for all examined materials. However, the capacitance sensor failed to measure the sudden change in mass flow rate synchronously with the digital scale. This phenomenon was predictable because it is attributed to the feature of a digital balance, which is always accompanied by an initial lag. Also, the results revealed that the vibrating stand had no effect on the sensor accuracy.

Keywords

Instrumentation

Sensor

Variable rate technology

Planters

Precision agriculture

Subjects