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United States Department of Agriculture

Agricultural Research Service

Title: Optimizing the Frequency of the Rotary Knife on a Roller Gin Stand

Authors
item Gillum, Marvis
item Armijo, Carlos - LAS CRUCES NM

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 23, 2000
Publication Date: August 1, 2000

Interpretive Summary: The rotary knife, stationary knife, and ginning roller on a roller gin stand all contribute to the actual separation of fiber and cottonseed. To prevent damaging the fiber during the ginning process, it is critical that the knives and ginning roller are operating at their optimum. The objective of the research was to determine the optimum frequency of the rotary knife. Taking into account fiber quality, cottonseed quality, lint turnout, bale value, and ginning rate, an experiment determined that the optimum rotary knife frequency occurs at 269 rpm. At rotary knife frequencies less than 269 rpm (not recommended), some of the ginning area on the roller is wasted, and roller damage is possible due to tags that cannot be cleared. At rotary knife frequencies greater than 269 rpm, compromises are made between ginning rate, seed cotton carryover, and choke-ups. (The manufacturer's specification for rotary knife frequency on nthe gin stand tested is 389 rpm.) The research findings improve the efficiency of the roller gin stand, making the fiber more desirable for spinning. Providing a superior fiber to the textile industry benefits both the cotton producer, in higher demand for his product, and the consumer, by providing a quality fabric.

Technical Abstract: An experiment determined the optimum frequency of the rotary knife on a roller gin stand. Six treatment levels of rotary knife frequency, 150, 300, 450, 600, 750, and 900 rpm, were chosen. (The manufacturer's specification for rotary knife frequency on the gin stand tested is 389 rpm.) The factors considered in determining the optimum rate included fiber and cottonseed quality, lint turnout, bale value, and ginning rate. There were no significant differences due to treatment with respect to fiber properties. With the exception of linters content, there were no significant differences due to treatment on the cottonseed properties. Linters content ranged from 1.7 to 2.88% on the 300 and 900 rpm treatment, respectively. Lint turnout and bale value were not significantly different due to treatment, averaging 35.3% and $438.71 overall. Ginning rate was significantly different due to treatment; the highest rate occurred on the 300 rpm treatment and was 350 kg/m/h (1.90 bales/h). Using regression analysis, the optimum rotary knife frequency occurs at 269 rpm. At rotary knife frequencies less than 269 rpm (not recommended), some of the ginning area on the roller is wasted, and roller damage is possible due to tags that cannot be cleared. At rotary knife frequencies greater than 269 rpm, compromises are made between ginning rate, seed cotton carryover, and choke-ups.

Last Modified: 11/27/2014
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