• By Ross Rutherford •
Contamination in seed cotton and lint cotton has been a critical issue facing the cotton industry for decades. This has become even more urgent in recent years with the broad acceptance/usage of cotton harvesting equipment with on-board module-making capability (round modules) wrapped in plastic.
For many reasons, whether from the module wrap or from plastic being blown into fields (shopping bags, drink cups, etc.), the problem has manifested itself so badly that new cotton classification grades of 71 and 72 were introduced by the U.S. Department of Agriculture Agricultural Marketing Service into the marketing system.
Of course, preventing contamination from reaching the gin plant has always been the best way to address the problem, and the National Cotton Council has worked tirelessly through the years to educate the industry about the perils of contamination.
However, the significant negative economic impact (through heavy price discounts for contamination calls) led Cotton Incorporated to fund research with the USDA-ARS ginning labs to develop means of detecting and removing contamination within the gin plant.
Developing A Prototype
One of the most promising was developed by the USDA-ARS Gin Lab in Lubbock, Texas. They worked with Des Moines, Iowa-based Bratney Cos., which has vast experience in optical sorting, to design a visual detection and removal system mounted above the open feeder apron of the extractor feeder over the saw gin stand. The prototype unit — installed and tested at Meadow Co-op Gin in Meadow, Texas — showed encouraging results.
Here is how the concept works. Cameras are mounted across the entire feeder apron (e.g., eight cameras on a 96-inch-wide feeder). Each camera views approximately 14 inches of apron width (providing a small overlap of coverage).
Every pixel is analyzed to determine color. Based on color, the computer software sorts every pixel, categorizing it as either “good” or “bad.” Good is considered anything that “looks” like cotton, stainless steel (the background of the feeder apron) and shadow area (area untouched by sufficient light to determine color).
A “reject” is considered contamination or foreign material and comprises all the colors outside the profile. If there are enough reject pixels next to each other, the software algorithm classifies the pixel cluster as an object to remove.
Based on the location on the apron, the computer decides which air knife (or knives) to fire in order to effectively remove the contamination. The air knives then release a blast of compressed air to take out the contamination.
Based on the prototype results, Lummus Ag Technology partnered with Bratney Cos. to produce commercial models of the design, marketed as the VIPR (Visual Imaging Plastic Removal) System.
The initial design of the commercial VIPR unit was for a 96-inch-wide Lummus Model 700 Extractor Feeder (the same model feeder used in the prototype installation at Meadow). Three of these units were installed in late fall 2019 at Southeastern Gin & Peanut Inc. in Surrency, Georgia, and tested in December 2019 and January 2020.
Results from these tests (using five different types of plastic module wrap) demonstrated cumulative detection/ejection efficiency over the three VIPR units of 89.44%.
While no system can detect and/or remove 100% of contamination in the gin plant, these results are certainly impressive. The three units will be operating again this fall, along with a single VIPR unit to be installed in west Texas near Lubbock.
The VIPR System is commercially available through Lummus on a limited basis for the 2021 ginning season.
Ross Rutherford is vice president, product management and marketing, Lummus Ag Technology, Lubbock, Texas. Contact him at email@example.com.