Measuring Seed Cotton Mass Flow Rate By Pressure Drop Across a Blowbox: Gin Testing

The ginning industry has expressed interest in a seed cotton mass flow rate sensor, as this device could provide useful information to gin managers and the feedback needed to develop improved process control systems. Previous research has demonstrated the feasibility of a seed cotton mass flow rate sensor based on measuring the pressure drop that occurs across a blowbox when seed cotton is fed into a pneumatic conveying system. This initial prototype has been improved and installed in the full-scale gin at the USDA-ARS Cotton Ginning Research Unit (CGRU) and a cooperating commercial gin. The blowbox pressure drop, along with additional pressure and temperature measurements, were used in a mathematical model to predict mass flow rate. The model was calibrated by conveying a known mass of seed cotton through the system and integrating the model over this time. Two feed rates, two air flow rates, two dryer temperatures and two cultivars were tested at the CGRU in a split-plot design with three replications as the main blocks and air flow rates as sub-blocks. The effects of these variables on the model were determined and model accuracy was evaluated. The commercial gin weighed round modules during the unwrapping process. Separate sets of module weights were used for calibrating the model and evaluating model accuracy.