Title: Determining Seed Cotton Mass Flow Rate by Pressure Drop Across a Blowbox: Gin Testing Author
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 10, 2014
Publication Date: N/A
Technical Abstract: Accurate measurement of the mass flow rate of seed cotton is needed for control and monitoring purposes in gins. A system was developed that accurately predicted mass flow rate based on the static pressure drop measured across the blowbox and the air velocity and temperature entering the blowbox. However, this prototype was only evaluated using small-scale equipment and the conveying air was not heated for drying purposes. An experiment was conducted using commercial ginning equipment. The mass flow rate measurement system was installed at the blowboxes under the steady flow feed control (first stage drying system) and the stick machine (second stage drying system). Drying temperature, seed cotton mass flow rate, air velocity, and cotton cultivar were varied to determine their effect on the accuracy of the mass flow measurement system. Mean absolute error in predicting seed cotton mass was 11.3% for the first stage system and 10.4% for the second stage system, worse than the 7.4% error obtained during previous testing with the small-scale conveying system. Cultivar had no effect on the model regression coefficients. Significant differences existed between the regression coefficients of different air velocities and feed rates for both first and second stage systems and dryer temperatures for the second stage system. The commercial ginning system utilized a combination negative and positive pressure conveying system, while the small-scale system used negative pressure conveying. Additionally, air velocity was varied in the commercial ginning system by adjusting slide valves. These factors likely affected the actual air velocity through the blowbox and the system accuracy. Modifications to the mass flow rate measurement system have been made and further testing will be conducted.