Mass flow sensor for combines with bucket conveyors

Most commercially available yield monitoring technology for grain harvesting equipment is designed to work with paddle-type clean grain elevators. There are some harvesting machines such as peanut and dry edible bean harvesters that use bucket conveyors to move grain from the cleaning shoe to the clean grain tank. This conveyor design prevents the use of currently available impact plate, optical, or radiometric mass flow sensors. Thus, a torque-measurement technique was developed for sensing mass flow rate through a bucket conveyor. One potential advantage of this technology, especially for developing countries, is that in-field calibration can be performed with static weights thus eliminating the need for weigh carts or immediate weigh scale receipts. Using empirical model parameters found in literature for a similar conveyor system, the mass flow rate based on the static torque calibration was slightly overestimated. The slope coefficient of the regression between the reference and the estimated mass flow rate was approximately 1.12 and 1.07 for steady stead and varying flow rate tests conditions, respectively. After adjusting empirical model parameters, the mass flow rate computed based on a static torque calibration was the same as the reference for the steady state flow conditions.