Real-time monitoring of the mass flow rate of granular materials in the seeder tube using a piezoelectric sensor

It is difficult to accurately measure the flow rate of seeds and fertilizers in grain drills, because the granules move in a continuous dense state. The purpose of this research was to monitor the mass flow of granular materials in the fall tube of the drill using a piezoelectric sensor. The laboratory system consisted of a repository box, a fluted roller metering device, a fall tube, and a piezoelectric sensor. To simulate the drill movement in the field, a vibrating stand was designed to oscillate the set-up in two perpendicular directions. The maximum amplitude stand was 8.99 cm according to the peaks and depressions available in a field after plowing. The sensor was evaluated in two static and dynamic modes for wheat seed, alfalfa seed, and triple superphosphate fertilizer with the usual drilling rate. The results showed the output signal of the sensor was proportional to all different mass flow rates in both static and dynamic states. The correlation coefficient was 0.95, 0.99, and 0.98 in static mode and 0.93, 0.86, and 0.98 in dynamic mode for wheat, alfalfa seed, and triple superphosphate fertilizer, respectively. In addition, the piezoelectric sensor could instantaneously monitor the sudden changes in the mass flow according to the reading of the digital scale. The results showed that the developed sensor can be used to monitor the mass flow rate of seeds and fertilizers in drills for calculating the drilling rate in real time.