Plastic imaging, detection, and ejection system (PIDES) for cotton gins: results from commercial testing and system updates

Authors: Holt, Gregory; Pelletier, Mathew; Wanjura, John

Submitted to: World Cotton Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/21/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Background: Plastic contamination in cotton lint costs the U.S. cotton industry approximately $750 million per year. Consequently, the removal of plastic contamination in cotton lint is an issue of top priority to the U.S. cotton industry. One of the main sources of plastic contamination showing up in marketable cotton bales, at the U.S. Department of Agriculture’s cotton classing office, is plastic from the module wrap used to wrap cotton modules produced by the new John Deere round module harvesters. Despite diligent efforts by cotton ginning personnel to remove all plastic encountered during unwrapping of the seed cotton modules, plastic still finds a way into the cotton gin’s processing system. To help mitigate plastic contamination at the cotton gin, ARS and industry partners developed a Plastic Image Detection and Ejection System (PIDES), which efficiently detects and removes plastic contamination during post-harvest processing of cotton. Because cotton gins have extremely low profit margins, the PIDES system was specifically designed to be much less expensive than the detection and removal technologies used in food crop industries, such as almonds and soybeans. PIDES is a “bolt on” system, built using off-the-shelf parts, such as cell phone cameras and embedded processors. These detectors are coupled to a pneumatic ejection system, via custom electronics, which blows plastic contamination out of the cotton-processing stream. Results: The PIDES system was evaluated at the USDA-ARS gin lab in Lubbock, Texas at two ginning rates, 9 bales/hr and 13 bales/hr, using three colors of plastic (blue, yellow, and pink) and three sizes (5x5, 10x10, and 10x20 cm). Three replications of each color and size of plastic were evaluated. Overall removal efficiency at 9 and 13 bales/hr across all sizes of plastic for the yellow, pink, and blue colors were 97%, 98%, 94% and 96%, 90%, 80%, respectively. The drop in overall efficiency from 94% to 80% for the blue wrap was primarily due to the smaller 5x5 cm samples curling up into round tubes due to static electricity as well as the samples being from the more transparent layers of the plastic wrap. When the system was tested in a commercial cotton gin, two colors (pink and yellow) and three sample sizes (5x5, 10x10, and 10x20 cm) were evaluated at a ginning rate of 15 bales/hr. Three replications of each color and size plastic were performed. Overall efficiency for the 5x5, 10x10, and 10x20cm samples for both colors was 75%, 90%, and 94%, respectively. The difference in efficiency between colors (pink and yellow) of each sample size was negligible. Conclusion: To address the issue of plastic contamination primarily occurring from round module plastic wrap, a system was developed (PIDES) to detect and eject the contaminate prior to the seed cotton entering the gin stand. Lab testing of the system indicated results ranging from 80% to 97% efficiency depending on the size and color of the plastic contaminant. During commercial testing, the PIDES technology, which is now being sold commercially by a leading cotton gin machinery manufacturer as VIPRTM, demonstrated an overall efficiency across sample size and color of 86% of removing plastic contamination. The technology was transferred to industry partners under a research agreement which began in October 2018 with the first commercial units sold in December of 2019 and successfully tested in January of 2020. Improvements, such as autocalibration, image capture, velocity measurement, and other features, to the PIDES technology continues in an effort to enhance functionality to the ginner.