Differential Roller Ginning of Upland Cotton
Cotton Ginning Research
2011 Annual Report
1a.Objectives (from AD-416)
Roller ginning, when compared to saw ginning, does the least amount of damage when separating the fiber from the seed. Roller ginning produces a superior fiber with excellent spinning potential. Currently, roller ginning is used primarily to gin the Pima cotton crop (about 3% of the total U.S.), and a smaller niche market of high-quality Acala upland cotton in California. The objectives of this research are to determine if roller ginning can remove only the longer and more desirable fibers off of upland cottonseed in a primary ginning process, and then remove the shorter fibers left on the cottonseed in a secondary ginning process. The improvements in fiber length obtained with differential roller ginning may earn a substantially higher price as well as open up new markets for better-quality upland fiber.
1b.Approach (from AD-416)
Theoretically, differential roller ginning selectively removes only the longer fibers off of upland cottonseed by controlling the dwell time and proximity of seed cotton at the ginning point on the gin stand. This may be accomplished with newly designed rotary and stationary knives. Modifications may be needed at the feeder to separate the partially ginned seed cotton prior to the secondary ginning process, and at the lint cleaner to ensure precise feeding and loading of lint onto the cleaning cylinder. Formal experiments will determine the performance of the experimental rotary and stationary knives, and of any machinery changes at the feeder and lint cleaner.
Preliminary tests were conducted on removing only the longer fibers off of upland cottonseed in a 1st ginning stage on a roller gin, and then removing the less desirable shorter fibers left on the cottonseed in a 2nd ginning stage. Three newly designed stationary knives attempted to control the movement of the cottonseed in relation to the ginning point with recesses of varying angles located a short distance from the tip of the stationary knife. The recesses prevented the cottonseed from returning to the ginning point to remove the shorter fiber. The stationary knives were tested in conjunction with varying speeds of the rotary knife. One design of stationary knife that yielded fiber significantly longer than fiber from a saw gin will be tested further. In addition, a newly designed lint cleaner feed works was installed in the roller ginning laboratory. The feed works may improve the cleaning efficiency of mill-type lint cleaners found in some roller gins by feeding individual tufts of fiber (as opposed to a batt of fiber) to the lint cleaner. The new feed works would complement improvements in fiber length obtained with differential roller ginning. This research will be the basis for a future journal publication.
Communication between the Lummus Corporation and the ADODR occurred by e-mail and/or telephone twice a week.