Finger Stripper Harvesting Technology
|Mike Bader, University of Georgia
|Alan Brashears, Agricultural Engineer, USDA-ARS, Lubbock, TX
|Tim Deutsch, Division Engineer-Cotton, John Deere Des Moines Wks., IA
|Cris Hanson, Program Manager-New Cotton Harvesting, Case Corp., East Moline, IL
Finger-type stripper heads were developed in the 1960’s, and have been commercially available since 1971. This stripper uses a series of 1-inch angle-iron fingers to remove the bolls from the plants. This type of stripper head has seen resurgence for use in the Ultra-Narrow Row Cotton. It is simpler and less expensive than a brush-type head and requires low maintenance. The finger-type strippers work well only under a limited range of conditions. Since this type of head has not been in use for some time, they are in the process of being somewhat redeveloped to be used on the larger and more modern strippers in use today. Modern strippers are equipped with extractor units, which separates some of the burrs and foreign matter from the lint. The panelist gave an overview of past experiences with stripper cotton, current activities in the Ultra Narrow Row Cotton, and the limitations and benefits of finger stripper heads.
Alan Brashears started the session by giving a brief history of the development of the finger stripper and narrow row cotton. Most of the data presented came from the 1970’s. The general conclusion from these tests was that burrs were not the problem. Sticks and fine trash were more of a problem. It was noted that keeping the stick content at 2% or less at the feeder apron of the gin stand lowered the odds of getting bark grades. The introduction of field cleaners helped lower the amount of foreign material in the seed cotton. Field cleaners are about 55% efficient in removing foreign material. Most of the data indicated that finger stripped seed cotton contained about twice as much foreign material as spindle picked seed cotton. It was noted that all of the tests may not have been from high density plant stands or cotton rows of 10 inches or less.
Alan next gave some information concerning the operation of field cleaners. The closer the grid bars are to the saws, the more cleaning is done; however; this reduces the cleaning capacity and, in turn, machine capacity. He stated the lay down bar on the top cylinder could be replaced with a brush to drop out rocks and help reduce the chance of fires. Harvesting green cotton can plug saw teeth. Spraying a textile cleaning material on the saws can help prevent this problem. Seed-cotton moisture should be 12% or less if it is passed through a field cleaner. Cotton with free moisture or moisture above 12% that is cleaned with a field cleaner can become tangled and knotty. By-passing the field cleaner will help in harvesting cotton with high moisture content, but will cause major problems at gins equipped to handle only spindle picked cotton.
Finger strippers were developed to strip cotton that was 22 inches in height or less. The finger stripper has not changed much in the past few years. Cotton that is 22 inches or higher will not pass through the stripper fingers easily and may be pulled up. Under wet conditions spindle pickers can be operated for more hours a day than strippers. The operating window for a finger stripper is more limited than for a brush stripper or a spindle picker. This may be off set by UNRC being harvested earlier when daylight is longer. Within the past few years, conventional brush strippers are operating in greener cotton to help reduce bark grades. This may or may not hold true in finger stripped cotton.
Tim Deutsch from John Deere said that their assessment of UNRC is that it may open up new opportunities in the Cotton Belt. They are in the process of assessing the market. It may have the potential to move cotton into marginal land and lower the cost of harvesting. John Deere is currently developing a header for UNRC. They feel that there will be enough UNRC acreage to justify providing a stripper header for the 7455 stripper.
John Deere will conduct basic stripper operation training in areas where strippers are moving into traditional spindle picker areas. They will have a video on strippers that address the cleaner operation and machine maintenance.
The ability to efficiently harvest UNRC depends on the production practices. To efficiently harvest the crop it must be short, slender, clean of weeds, and dry. The crop has to be the focus. Crop management effects the productivity of the stripper, quality of cotton, and the efficiency of the stripper header to remove cotton from the stalk. Under normal operating conditions a stripper is not as productive as a spindle type picker. Strippers can not be operated as many hours a day due mainly to the fact that stripper cotton needs to be drier and contain no free moisture in contrast with spindle picked cotton. A good plant population is the key to UNRC production. The crop has to be harvested early while days are longer to make the practice work. A small plant is needed to help reduce bark problems. Cleaners will not efficiently remove bark. The goal is to make finger stripped cotton as efficient to harvest as spindle picked cotton.
Case Corporation’s Cris Hanson stated that Case is comparatively new in the UNRC and stripper area and could not comment on whether or not plans exists to introduce a harvester. Today’s group has gathered to discuss UNRC and essentially, give UNRC the opportunity to succeed. With the focus on harvesting though textiles, Cris summarized his presentation with the following possible industry and/or university project proposals.
To improve overall cotton quality (would like to approach picker quality), three projects were proposed. The first was examining harvester header materials less likely to cause contamination. Another project would be the plant contact design in both the header and cleaner. The last project was to create additional harvester and gin projects by identifying textile industry issues.
The next set of proposed projects were regarding cotton cleaning. While cleaners (burr extractors) are necessary on current UNRC harvesters and probably always will be, this group could address that issue in conjunction with gin and textile issues. Advancing cleaner technology would expand hours of the current harvester.
The last proposal was simple economics. Overall profitability is driving the UNRC adaptation. The industry needs a project to develop a basic understanding of the profitability drivers for the entire UNRC process through the textile industry.