Showing posts with label Ginning. Show all posts
Showing posts with label Ginning. Show all posts

Cotton Gin | How it Works

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INTRODUCTION TO A COTTON GIN

Cotton fibers must be separated from the seed (ginned) before they can be used to manufacture textile goods. The first machine to gin cotton was the "Churka" gin. The "Churka" gin was most efficient when handling naked seeded varieties with loosely attached fibers. Early American settlers found that the fuzzy seeded varieties that yielded best in this country were difficult to gin on a roller gin. Consequent­ly, the fiber was generally pulled from the seed (ginned) by hand until Eli Whitney patented his gin in 1794.

Whitney's gin used spikes on a hand-driven cylinder to remove fibers from the seed. The spikes pulled lint through slots that were too narrow for the seeds to pass. A revolving brush then removed the lint from the spikes. Whitney's gin could process as much cotton as 100 people could gin by hand. This invention en­abled cotton growers to rapidly expand production, and marked the beginning of the modern cotton industry.

Henry Ogden Holmes received a patent in 1796 for an improved gin that used saws rather than spikes to remove the fibers from the seed. The saws were spaced on a shaft to provide openings that allowed the clean seed to drop out the bottom. Holmes' invention made ginning a contin­uous rather than a batch process, and greatly increased capacity. The basic principles developed by Whitney and Holmes are used in modern gin stands, but there have been many improvements.

When cotton was hand picked and carefully handled, the only machines needed in a ginning system were a gin stand, a baling press, and conveying equipment. Rougher hand harvesting meth­ods and mechanical harvesters caused more moisture and for­eign material (trash) to be mixed with the seed cotton. Thus, seed cotton cleaning and drying equip­ment and lint cleaners were developed to compensate for the trashier harvesting methods. Currently, about three-fourths of the U.S. crop is harvested with spindle pickers and one-fourth with mechanical strippers.

There is a major difference in the trash content of the spindle picked and stripper harvested seed cotton. On the average, about 2,200 pounds of stripped seed cotton containing about 800 pounds of trash are required for a 480-pound bale of lint. About 1,500 pounds of spindle picked seed cotton, containing about 120 pounds of trash would be re­quired for a bale.

Storing Seed Cotton

Seed cotton can be safely stored in modules or trailers if its moisture content is kept at 12

percent or less. Wet cotton or cotton containing green plant material will heat during storage and quickly deteriorate. Cotton damaged in this manner produces low grades and poor quality seed. Fresh modules should be checked daily. If the temperature inside a seed cotton module exceeds 110°F, it should be ginned imme­diately to prevent further deterio­ration.

Modules of dry seed cotton should be carefully formed so water will run off the top and sides, placed on a well-drained site, and covered with good quality tarpaulins.

Cotton rope should be used to anchor the module coverings. Plastic twine should not be used to tie down covers since pieces of this material can get into the cotton and become a serious contamination problem at the textile mill.

Machinery in the Saw Ginning system

Quality preservation during ginning requires the proper selection and operation of each machine in a ginning system.

Automatic Feed Control

Gin machinery operates more efficiently when the cotton flow rate is constant. In early gins the flow rate was often erratic be­cause of the variable work rate of the man operating the unloading system. The automatic feed con‑

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trol was developed to solve this problem by providing an even flow of cotton to the gin's clean­ing and drying system. A me­chanical module feeder also per­forms a similar function and may be used to feed seed cotton directly from a module.

Green Boll Trap

The green boll trap is impor­tant for removing green bolls, rocks, and other heavy foreign matter from rough cotton. These large, heavy materials should be removed early in the ginning sys­tem to prevent damage to ma­chinery and to preserve fiber quality. Green boll traps use sudden changes in flow direction and/or reduced air velocities to separate heavy foreign materials from seed cotton. A typical green boll trap is shown in Figure 1.

Driers

The most important factor in preserving quality during ginning is the fiber moisture content. At higher moistures, cotton fibers are stronger, but trash is harder to remove and cleaning machinery is less efficient. Consequently, selecting a ginning moisture con­tent is a compromise between good trash removal and quality preservation. For most condi­tions, cotton should be ginned at 6 to 7 1/2 percent lint moisture.

The tower drier is the most widely used gin drier. Tower driers commonly have 16 to 24 shelves arranged so cotton must slow down while making turns through the machinery (Fig. 2). Heated air conveys the cotton through the shelves in 10 to 15 seconds. Practically all of the approximately 1,600 gins in the United States are equipped with at least one stage of seed cotton drying, and most ginning sys­tems have two stages.

The temperature of the convey­ing air is regulated to control the amount of drying. To prevent fiber damage, the maximum tem­perature in the drying system should be kept below 350 °F. The temperature control sensor should be located near the en­trance to the drier and a maxi­mum temperature limit switch should be located between the burner and the mix point to keep the temperature below 350°F. If the temperature control sensor in your gin is located near the bot­tom of the drier, the reading may be 200-240 degrees lower than the temperature at the mixpoint.

Seed Cotton Cleaners

Seed cotton cleaners (cylinder cleaners) consist of six or seven revolving spiked cylinders that turn about 400 r.p.m. (Fig. 3). These cylinders convey the cotton over a series of grid rods or screens, agitate the cotton, and allow fine foreign materials such

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as leaf trash and dirt to fall through openings for disposal. In many gins, two cleaners are

installed in parallel (split stream), with each one cleaning half the seed cotton.

Seed cotton cleaners break up large wads and generally get the cotton open and in good condi­tion for additional cleaning and drying. Cylinder cleaners may also be used to remove seed cotton from the hot air line as it comes from the drier. They may be used in either a horizontal position or inclined at an angle of about 30 degrees (inclined cleaners).

Stick Machines

The stick machine (stick and green leaf machine) was devel­oped to remove the extra foreign matter taken from the plant by mechanical harvesters (Fig. 4). Stick machines use the centrifu­gal force created by high-speed saw cylinders to sling off foreign material while the fiber is held by the saw.

Inside a stick machine, seed cotton is wiped onto the sling-off saw teeth by stationary wire brushes. Grid bars or stationary wire brushes are located around the saw cylinder to reduce the amount of seed cotton that is thrown off the cylinder. Some models have two sling-off cylin­ders while others use only one.

The seed cotton which is thrown off with the foreign matter is picked up by reclaimer saws and put back into the seed cotton stream. Reclaimer saw cylinders are similar to main sling-off cylinders, but usually run slower and have more grid bars. The foreign matter that is slung off the reclaimer feeds into the trash handling system.

Extractor-Feeders

The primary function of an extractor-feeder is to feed seed cotton uniformly to the gin stand at controllable rates (Fig. 5). Seed cotton cleaning is a second­ary function. Feed rollers, lo­cated at the top of the extractor-feeder and directly under the distributor hopper, control the feed rate of seed cotton to the gin stand. These feed rollers are powered by variable-speed motors controlled manually or automatically by various inter­locking systems with the gin stand.

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Gin Stand

The gin stand consists of a set of saws rotating between ginning ribs (Fig. 6). The saw teeth pass between the ribs at the ginning point. Here the leading edge of the teeth is approximately paral­lel to the rib to pull the fibers from the seed rather than cutting them.

On traditional gin stands, cotton enters the stand through a huller front (Fig. 7). The saws grasp the cotton and draw it (in locks) through a widely spaced set of ribs known as "huller ribs". This causes hulls and sticks to fall out of the machine. The locks of cotton are drawn into the bottom of the roll box through the huller ribs.

Newer gin stand designs have eliminated the huller fronts, dropping the seed cotton directly into the roll box from the feeder apron (Fig. 8). This change increases stand capacity, but obviously eliminates the final stage of seed cotton cleaning.

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The actual ginning process (separation of lint and seed) takes place in the roll box of

the gin stand. When all the long fibers are removed, the seeds slide down the face of the gin­ning rib between the saws and fall onto a conveyor under the stand. Lint is removed from the saw by a rotating brush or by an air blast. It is then conveyed to the next machine in the ginning system, usually a lint cleaner.

Saw-Type Lint Cleaner

In the lint cleaning process, a condenser removes the fiber from the conveying air stream and forms it into a batt (Fig. 9). The batt is introduced to the lint cleaner saw cylinder which nor­mally rotates at approximately 1,000 revolutions per minute. The saws carry cotton over grid bars which, aided by centrifugal force, remove immature seeds (motes) and foreign matter. The cleaned lint is removed from the saw by a rotating brush which also provides air to convey it to the next machine.

Lint cleaners can improve the grade of cotton by removing for­eign matter if the cotton has the necessary color and preparation characteristics. Lint cleaners may also blen'd light spotted cotton so that it becomes a white grade. But fiber length and several other important quality factors can be damaged by ex­cessive lint cleaning, especially when the cotton is too dry.

For average machine-picked cotton, the first stage of lint cleaning will remove 20-30 pounds of lint and foreign matter from each bale. The second lint cleaner would be expected to

remove an additional 10-12 pounds and the third stage about 6 pounds.

Determining the number of lint cleaners that gives maximum bale value is a compromise between increased grade and reduced length, turnout, and other fiber quality factors impor­tant to textile manufacturers. The price differentials for grade and staple length have a great

influence on this decision. Under most circumstances, one or two saw-type lint cleaners will give the best economic returns. Con­sequently, ginning systems should be designed so that all saw-type lint cleaners after the first stage can be by-passed.

Bale Press

Cotton must be baled and pack­aged to protect it from contami­nation during transportation and storage. The U.S. cotton indus­try has adopted the universal density bale with a nominal den­sity of 28 pounds per cubic foot. Universal density bales may be produced at a compress from modified flat bales, or they may be produced at the gin with a universal density (U-D) press. In 1990, approximately 85 percent of the U.S. crop was packaged in U-D bales at the gin.

Bale coverings and ties should meet the specifications devel­oped by the Joint Cotton Indus­try Bale Packaging Committee. Detailed specifications are avail­able from your county Agricul­tural Stabilization and Conserva­tion Service office or from the National Cotton Council.

Moisture

Moisture is the most important single factor affecting fiber qual­ity during ginning. When gin­ning at higher moisture contents, the average length of cotton fibers will be greater than if the same cotton was ginned at low moisture contents. However, trash is easier to remove from drier cotton. Consequently, de­termining a ginning moisture content is a compromise between

For spindle-picked cotton, the generally recommended machin­ery sequence is as follows (Fig. 10):

1. Rock and green-boll traps

2. Feed control

3. Tower drier

4. Cylinder cleaner

5. Stick machine good trash removal with some fiber length damage and length preservation with less lint clean­ing.

The ideal ginning moisture content is 7 percent, but mois­tures between 6 and 7 1/2 per­cent are acceptable. Ginning at moistures outside this range can cause machinery operation and fiber quality problems.

6. Tower Drier

7. Cylinder cleaner

8. Impact cleaner (optional)

9. Extractor feeder

10. Gin Stand

11. Lint cleaner

12. Lint cleaner

13. Press

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Machinery Systems Recommendations

Spindle-Picked System

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Machine-Stripped System

Since machine-stripped cotton that was not cleaned on the har­vester contains 6 to 10 times as much foreign matter as machine-picked cotton, ginning systems in stripper areas need more cleaning equipment to maintain fiber quality. The following sys­tem of gin machinery (Fig. 11) is generally recommended for stripped cotton:

1. Green-boll trap

2. Air-line cleaner

3. Feed control

4. Tower drier

5. Cylinder cleaner Stick machine

6. Tower drier

7. Cylinder cleaner

8. Stick machine

9. Stick machine (The optional stick machine is recom­mended only for stripped cotton containing in excess of 32 percent foreign matter (lint turnout less than 22 percent).)

10. Extractor feeder

11. Gin stand

12. Lint cleaner

13. Lint cleaner

14. Press

These recommendations are the maximum amount of machinery that should be needed. Any ma­chinery which is not necessary for the particular lot of cotton should be by passed. Driers, seed cotton cleaners, and lint cleaners should have bypass valves so they are not used un­less they are needed.

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Roller Gins

The first mechanical gin (Churka) was a roller gin consist­ing of two rollers (one metal, one hardwood) less than one inch in diameter, turned together by means of a hand crank. In 1840, Fones McCarthy invented a more efficient roller gin which con­sisted of a single leather ginning roller, a stationary knife, and a reciprocating knife which pulled the seed from the lint as the lint was held by the roller and sta­tionary knife. Although the McCarthy gin was a major im­provement over the Churka-type gin, machine vibration due to the reciprocating knife along with maintenance problems prohibited high ginning rates.

In the late 1950s and early 1960s, a rotary-knife roller gin was developed by the USDA Southwestern Cotton Ginning Research Laboratory, gin manu­facturers, and private ginneries. The ginning roller and stationary knife were retained from the McCarthy gin while a rotary knife replaced the reciprocating knife, eliminating the lost time of the backstroke of the reciprocat­ing knife and reducing the vibra­tion. The rotary knife allowed increased ginning rates and is currently the only roller-type gin used in the United States. A typ­ical rotary knife roller gin stand is shown in Figure 12.

Roller gins are used to preserve the quality of extra long staple (Pima) cottons grown in the western United States. Although only about 5 percent of the U.S. cotton crop is Pima, it is a highly valued specialty crop which de­mands a premium price. Roller gins are slow, averaging about 1 to 1.5 bales/hr/gin stand on good running cotton, compared to as much as 15 bales/hr/sawstand. Consequently, the cost of roller ginning is about 50 percent high­er than saw ginning.

Since it is a very valuable prod­uct, the harvesting, seed cotton storage, and seed cotton condi­tioning of Pima cotton are criti­ cal. Seed cotton conditioning equipment in roller gins is simi­lar to the type used in saw gins. Roller ginning systems normally include four or five seed cotton cleaners while a ginning system for machine picked upland cot­ton would normally include three or four seed cotton cleaners. Im­proper adjustment of seed cotton cleaning equipment causing

roping or recirculation of cotton can damage the quality of Pima cotton by stringing out and twisting the locks.

Tower dryers and hot-air cylin­der cleaners are commonly used for seed cotton drying. Optimum fiber-moisture content for roller ginning is 5 to 6 percent. Drying fiber lower than 4 percent may result in static-electricity prob­lems and fiber breakage. All United States roller-ginning plants have at least one stage of drying, 98 percent of the plants have at least two drying stages, and 59 percent have three drying stages. Drying temperatures should be monitored or automati­cally limited to no more than

300 °F because high drying tem­peratures damage fiber and waste energy.

The ginning roller is the most important and expensive compo­nent in the gin stand. Roller-covering material is made from 13 layers of plain-woven cotton fabric cemented together with a white rubber compound. The fabric lays on the bias so that neither the warp or fill yarn are parallel to the direction of cut­ting; this prevents the material from unraveling from the roller surface. The roller material mounts on to the roller core with the cut edges of the fabric layers serving as the ginning surface.

Rotary-knife roller gin stands separate fiber from seed by using the frictional forces between a moving roller and fixed station­ary-knife surface. During normal ginning, the roller-to-fiber force is greater than the stationary­knife-to-fiber force; therefore, the fiber sticks to the roller sur­face and slips on the stationary knife surface. Cotton is ginned as fibers adhered to the roller surface slip under the stationary knife which holds the seed.

Each stroke of the rotary knife clears the stationary knife edge of accumulated seed cotton and ginned and partially-ginned seed. Partially ginned seed are either pulled back to the stationary knife and completely ginned or swept along with the seed and carryover and later reclaimed.

At the ginning point, seed cotton trash is separated with about 45 to 50 percent going with the lint and the remainder with the seed.

The carryover reclaimer removes unginned and partially ginned seed cotton and spindle twist from the seed flow and re­turns them to the distributor for ginning. The reclaimer usually cannot distinguish between seed cotton and spindle twist. Most of the spindle twists are returned and accumulate at the gin stand, resulting in reduced ginning effi­ciency and premature wear of the roller and rotary knife. Carry­over percentage increases with feed rate but is typically less than 6 percent of the seed cotton fed.

Lint cleaning in roller gins is different from saw gins and varies among gins. Traditionally, the mill-type opener/air-jet lint cleaner combination was used to remove motes, broken seed, en­tanglements caused by the ma­chine pickers, and pin trash not removed in seed cotton cleaning. But because if low capacity, many of the mill-type openers have been replaced by cylinder and revolving screen (impact) cleaners used in combination with air-jet cleaners. Currently, the most common lint-cleaning sequence is an incline, impact, and air-jet cleaners (Fig. 13); 35 percent of the plants have such

an arrangement.

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U.S. DEPARTMENT OF AGRICULTURE
NATIONAL COTTON GINNERS ASSOCIATION

The National Cotton Ginners Association
Through The Support Of Its Member Associations

Arizona Cotton Ginners Association
California Cotton Ginners Association
Cooperative Ginners Association of Oklahoma
New Mexico Cotton Ginners Association
Oklahoma Cotton Ginners Association
Southeastern Cotton Ginners Association
Southern Cotton Ginners Association
Texas Cotton Ginners Association

Safety

Every employer has the responsibility of providing a safe working environment. Providing safe, comfortable working conditions is a good business investment when considering the costs of accidents and health problems. A general safety program should be developed for each gin, including the education of employees on unsafe conditions, practices, and behavior. Basic gin safety materials to create a gin safety program are available from your state/regional ginners association or from National

Cotton Ginners Association, P.O. Box 820285, Memphis, Tennessee 38182.

by W.D. Mayfield, National Program Leader, Cotton Mechanization and Ginning, Extension Service, USDA, Memphis, TN; R.V. Baker, S.E. Hughs, and W.S. Anthony, Research Leaders, respec­tively, USDA, ARS, Cotton Ginning Research Laboratories, Lubbock, TX; Mesilla Park, NM; Stoneville, MS

Read more...

Roller Ginning-GENERAL RESEARCH AND DEVELOPMENTS 1932-1940

Much preliminary work was accomplished between 1932-35 at Sacaton, Arizona. The ginning engineers and cotton technologists, in fiscal year, 1936 conducted an intensified series of informative roller ginning tests on. both cleaned and uncleared Pima cottons, during which the roller and crank speeds were varied from 110 to 150 and from 650 to 840 respectively, and other ele- ments were investigated. Cleaner feeders, an MEF (Lummus master extrac­tor feeder), and 3 cylinders of cleaning were employed in combinations.

In general, cleaned cotton and higher roller and crank speeds gave the best overall results.

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Four cottons were ginned with each of three crank speeds (650, 930, and 1200 rpm) with each of three 6-inch rollers having different types of roller covering (semi-self-grooving, half walrus and half packing, and spool-wound all-packing) at each of three speeds (100, 125, and 150 rpm) or 27 tests per cotton. Seven and 8-inch spool-wound all-packing rollers were also tested against the 6-inch roller with these cottons at a speed of 125 revolutions per minute and at the same periphery speeds as the 6-inch roller operated at 150 revolutions per minute, or 4 tests per cotton.

The optimum crank speed, as determined in the tests appeared to be between 800 and 900 revolutions per minute, preferably about 900 revolutions per minute if a long life, trouble-proof crank mechanism for high speed could be devised. Further development work involving long time mechanical engin­eering work was found to be necessaryto achieve practicable high speed crank mechanisms.

As compared to a crank speed of 650 and roller speed of 125 revolu­tions per minute, the tests showed that a crank speed of 930 and a roller speed of 150 revolutions per minute ginned an average of 34 percent more cotton, or increased ginning capacity 34 percent. Increased roller speed was a contribu­tor to increased capacity, but the increased crank speed was the main factor. The grade of the cotton was not affected by these increased speeds, and staple lengths was seldom appreciably or significantly influenced as brought out in classifications made at Phoenix, Arizona.

During 1941 new gins in the El Paso area and Pecos Valley of Texas, in the Mesilla Valley of New Mexico, and in the Gila and Salt River Valleys of Arizona operated successfully at crank speed of 800 to 840 revolutions per minute on a 24-hour day basis, and in some instances at 930 revolutions per minute where the ginning volume was small.

The 7-inch and 8-inch laboratory rollers were found in the tests to be at least a third slower in ginning capacity than the conventional 6-inch rol­ler, even when operated at the same speeds, and therefore, proved to be less satisfactory. Grade and staple length of the cotton was not affected by varia­tions in roller size.

Spool - wound all-packing gave slightly better ginning capacity than the semi-self-grooving roller or the half walrus and half-packing roller, but the grade advantages appeared to be barely in favor of the half walrus and half packing roller. The semi-self-grooving roller appeared to produce fewer neps and naps in the cotton than the other rollers.

Along with testing the rubber flap doffer and lint flue devised at the U. S. Cotton Ginning Laboratory, it was proposed to test various methods of overcoming or killing static, the effects of which, if severe, generally pre­vent the use of the doffers. A jet to place moist air on the cotton on the seed

grid was tried, but it did not function satisfactorily. All other efforts to de­vise methods of moistening the roller, except steam jets under the roller, were in vain. The series of tests was therefore reduced to 24 tests (6 cottons x 4 tests) or the following:

1. Brush stick for doffing.

2. Rubber flap doffer for doffing.

3. Rubber flap doffer and lint flue.

4. Wooden roller and gin roller and lint flue.

Some very valuable data and observations resulted from these tests. It was found first that the lint flue will work. The present design should be changed however. The piping should be altered to provide adequate air velo­city without excessive fan power. When lumps of lint that hang on the knife are finally drawn through by the roller, the air suction at the nozzle is not strong enough to pull the cotton into the lint flue.

Test observations indicated that with a lint flue, the doffer is not nec­essary because the air pulls the cotton from the roller and straightens out the fibers in a manner comparable to the effect of the mechanical doffer.

A new engineering design of lint flue nozzle with a large adjustable throat to fit partially over a wooden roller riding on the conventional gin rol­ler and partially over the gin roller has been built by the engineers for ship­ment to Sacaton for testing.

Very little static occurred at Sacaton during the time that the 1941 crop ginning tests were made, and steam lines were, therefore, not hooked up to the gins in an effort to overcome the static; but a number of observations were made and data were collected at commercial gins on the effects of steam de­vices in controlling static. It was found that steam made it possible for the ginner to use rubber flap doffers which improved the grade from one-third to one-half over the conventional brush stick doffer. The steam also materially increased ginning capacity. The application of steam in its present form has some objections, namely that the steam rusts the gin stand and makes a messy condition with dirt and trash under it.

For this reason some Arizona ginners discontinued the use of steam, although most of the ginners in the El Paso area still employ it as a static eliminator in order to use the doffers and also to obtain as high grade lint as possible. In the El Paso area the ginners aimed to turn out grades as high as. No. Z in order to command good prices. When the grades drop to No. 3, the value of the cotton is generally $25. per bale less than cotton of No. 2 grade. Girmers are therefore making every effort to keep the grades up, and this method of making the use of the doffer possible is one of the severalmeans employed for improving the grade of the cotton.

The tests at Sacaton showed that on 6 cottons, the average grade was 1.7 with the doffer as compared to 2.3 with the brush stick. When the lint flue was used, the grade was aboutthe same as whenthe doffer was used alone. Tests at commercial gins showed that the doffer improved the grade on an average of almost one-half grade on six cottons at one gin and one-third grade at another gin on six other cottons. When steam was used in these tests to make the doffer function better, the ginning capacity was increased 10 percent and the moisture of the lint cotton 1 percent.

There were 56 tests made on cleaning, drying, and conditioning which were completed on 7 cottons and involved the following:

1. No cleaning (control).

2. Once through. Mitchell.

3. Twice through Mitchell.

4. Once through Mitchell with 160 degrees F.

5. Twice through Mitchell with 160 degrees F. and 120 degrees F. respectively.

6. Once through Mitchell with after cleaning cylinders of Lumrnus.

7. Twice through Mitchell with after cleaning cylinders of Lurnmus.

8. Once through Mitchell with moist air.

The result of these tests indicated that when the cotton was passed through a double extractor unit, its grade was improved to an average grade of 1.6 from an average of 2.4 where no cleaning equipment was employed in cleaning the cotton. The cotton on hand was generally too dry to show any further favorable effects of artificial drying. By cleaning the cotton the gin­ning capacity was increased 12 percent. The average foreign matter content of the cotton was reduced from 2.8 to 0.8 percent by cleaning with a double extractor unit. While the passage of the cotton through two double extractor units and a cylinder cleaner reduced the foreign matter content only 0.2 per­cent below the average for the cotton after its passage through one double ex­tractor unit, the average grade was improved 0.2 grade.

Tests on the conditioning of cotton in extractor units indicated that it was necessary to clean the cotton thoroughly before conditioning it in such units prior to ginning. When steam was applied to the extractor unit, the staple length of the cotton was increased, but the grade improvements were lessened, and additional tests were made to determine the benefits of con­ditioning the cotton after cleaning it. The results of these tests are not here reported.

Moisture determinations were made at Sacaton on the seed cotton and ginned lint samples involved in the tests there and in commercial gin tests. Foreign matter determinations were made of the seed cotton sample before and after cleaning, conditioning, and drying by the various methods. Fiber length distribution studies were made on samples selected to represent ex-

treme ginning and handling conditions.

All of the lint samples were classed at Phoenix, and some samples representing important tests were also classed at El Paso to provide a double check on the conclusions to be made based on classification.

The 24 roller gin establishments in operation in the West in 1940 pre­viously mentioned were resurveyed by T. C. Walton in 1941 along with the 13 new gin outfits installed in 1941. The new gins had a total of 143 rollers. The other gins had a total of 346 rollers, bringing the total number in 1941 up to 489 as compared to 328 in 1940. In 1940 the roller gin plants ginned an ave­rage of 100 bales per stand; in 1941 approximately 150 bales per stand due to the expansion of SXP production in new areas of growth. Six of the new gins were installed in the El Paso Valley of Texas, 4 in the Mesilla Valley of New Mexico, and 1 in the Gila Valley and 2 in the Salt River Valley of Arizona. All except one of the plants were installed with doffers, but the doffers were used only when steam was successfully used in eliminating static.

While very good progress was made in the American-Egyptian cotton ginning investigations in 1941; there remain three unsolvedproblems especially in engineering developments. The engineers concluded that efforts should be made (1) to devise suitable crank mechanism for satisfactorily running the gins at high speeds, and better grids for shedding the seed faster; (2) to con­centrate on the improvements to the lint flue system for higher efficiency and economy; and (3) to develop acceptable methods for controlling or eliminating static. Unless the latter is accomplished, the lint flue may not be completely successful. Therefore, the main objectives of the program must involve fur­ther developmental work by the ginning engineering staff.

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Lint Flue Research, 1936-45

Lint flue studies which began in 1936 continued to 1945 and included first, the series A or round lint flue shown in drawing fig. 54 and depicted in photo fig. 61, on page 77.

When roller ginning problems again demanded attention, in 1941 much of the research work was conducted at the Pirna Indian Agency roller gins, Sacaton, Arizona, where cooperative work of the Department was then being handled in the production of Pima Cotton. Figure 61 shows one phase of this work.

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In the second or series B types of suction lint flue studies, a graduated rectangular supplanted the previous round flue as was shown in fig. 62. Sev­eral nozzles with 4 x 4-inch take-offs were tested between the gin stands and graduated rectangular lint flue. The best nozzle is shown in fig. 63.

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The series A and B types, illustrated in previous figs. 61 and 62, of lint flues were superseded by the series C overhead systems developed by Agricultural Engineer Gerald N. Franks in 1943. This new system marked a radical departure from previous studies. All trunks were rectangular and graduated in size, each stand take-off being 6 x 6 inches square, with dam­pered suction regulators, U-tube water gauges, and hinged nozzles. Figure 64a is an interior photo taken at the SanCarlos roller gin, Casa Grande, Ari­zona, (Courtesy Western Cotton Products Co.) and fig. 64b gives nozzle de­tails.

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In the tests at the San Carlos gin from 1943 to 1945, 12 McCarthy type 40-inch roller gin stands were employed, grouped in threes per gin flue for delivery tothe condenser main intake trunk. Cranks operated at 807, pushers at 165, rollers at 100, line shaft at 360, and counter shaft at 400 revolutions per minute. A type C size 45 fan wheel in a size 50 Boardman fan casing operated at 1614 rpm. This fan drew 8356 cubic feet of air per minute at 6" water gauge static pressure, 2. 7" velocity pressure, and 33 horsepower load.

A total of four gin trunks increased in size from 6-5/8 inches square to 9-1/4 inches square to 11-1/2 inches square for each three stands andthen delivered into a 46 x 11-1/2 inch rectangular overhead main duct to the suc­tion condenser.

During the operations on August 19, 1943, air volumes of 760 to 700 cfrn per gin stand handled the roller delivery satisfactorily. The regulated air nozzles below the rollers showed static pressures on the roller hood ran­ging from 0.7 inch to 0.3 inch. On September 12, 1945, Western Cotton Pro­ducts Co. reported ginning 70 bales of SXP cotton for the 1944 season. U-tubes were attached below the hinges of the nozzle hoods, and adjustable dam­pers enabled the operator to maintain uniform suction on all rollers. This usually averaged 1/2 inch on the individual U-tubes.

The principal value of these developments resided in the fund of prac­tical information obtained by the Ginning Laboratory and the proving that gin­ned lint from roller gins could be pneumatically conveyed to the press without damage and considerable saving in hand labor. It was found that 700 cubic feet of air per gin stand was desirable for the design here described, but lesser volumes are possible with minor changes in the nozzles. Fan horse­power per gin stand, as shown on special power readings taken August 19, 1943, ranged from 2.75 to 3.17 horsepower per stand, and air volumes ran­ged as above stated. Full construction details are on file at the Southwestern Cotton Ginning Research Laboratory.

The final conclusions, reached from these extensive experiments with roller ginning suction lint handling systems, were dual. First, the system used at the San Carlos gin proved that roller ginned long staple cottons, such as Pima and sea-island varieties, could be pneumatically handled in lint flues without damage to quality or smoothness of the sample and that minor change of the Franks' design, in the light of information provided by the tests, would make the system feasible for commercial use. Second, that objections to heavy power consumption and first cost of construction involved in the test designs could be largely overcome by using a single larger lint flue, a double box press with improved suction condenser, smaller nozzle areas at the gin­ning rollers, and careful redesign of dimensions in the major elements.

"Cooperative Tests and Results at San Carlos Roller Gin, Casa Grande, Ariz. "

Note: The Western Cotton Products Co. (throughtheir. Mr. Tom RoLlow, Mgr. and L. A. Brewster, Master Mechanic) arranged informally with Young for a series of trial tests of the crankassembly at the San Carlos Gin. Twenty-four stands were in the San Carlos ginxtery and the test one with Government crank assembly was operated at 840 crank speed; 110 rpm roller speed, and without doffer.

"After 500 hours of almost continuous operation, the #6 tapered pin shown in photo No. 1910 was sheared. For this, the ginner first substituted a 7/16-inch straight bolt, but within 100 hours of operation a 1/2-inch straight bolt was inserted. After 640 hours, one wooden bearing of a crank leg went out at the top, and the experimental apparatus was removed from the stand. Main bearings, oil housing, felt seals, cross rail all showed O.K. Wear on

* Government file photos #1910 and 1011, not here reproduced.

crankshaft was . 0003; on crank legs . 0005; on wrist pins . 004; on crank leg oil sleeve .007. It was noted that the crank rail should have a center support.

"In the San Carlos Gin at Casa Grande, other roller gin stands were fitted with ball-bearing eccentrics developedby Mr. Brewster, whose estimat­ed costs have never been given to us. These required new steel framing under the stands made of 6" x 3" I-beams. Mr. Brewster's eccentrics have been very good, but they also go out of service from time to time. He has been operating these at 807 to 980 rpm at San Carlos Gin with rollers at 100 and pushers at 165.

"Lubrication of roller gin. crankshafts, crank legs, and wrist pin bear­ings is one of the greatest problems in roller ginning, and especially in the modernization and maintenance of the older McCarthy type gins. Oil-soaked wooden bearings on crank legs have been used in the Southeastern states and in the Southwestern irrigated regions for many years, but the speeds of the cranks have had to be held down to about 600 rpm, and very frequent oiling has been required. Brewster's use of Micarta wedge blocks (a bakelite com­position) against steel pins for the upper bearing of the crank legs (wrist pin bearing) has proved satisfactory to the Western Cotton Products Co., and his development of large size ball-bearing eccentrics, sealed in with Zerk fittings for greasing, have been used in many of the company gins.

"Armour of Phoenix produced bronze crank legs with hollowed reser­voirs, but these have been rather clumsy and heavy. Ha.rdwicke-Etter. Co. , and Murray Co. , on their newest roller gins have employed both ball and bronze bearings.

"In the 1942 design of crank and crank legs here reported, the main bearings probably required lubrication every 1000 hours of operation. The wrist pins on this equipment required lubrication every 24 hours.

"Feeding oil into the main cranks in an improved design may be a for­ward step on the part of the Department. In this improvement, oil would be supplied to a hole in the end of the main crank shaft, thence through an oil hole to the pin where centrifugal force would assist in the lubrication. This method would simplify construction of the oil housings and seed guards now needed.

"For lubrication of wrist pins at the top of the crank legs, a real im­provement over old unsatisfactoryznethods could be made by using oil-bearing bronze bearings which go under trade names such as 'Oilite' and 'Compol to indicate that they are oil retaining. Use of these materials would probably necessitate only minor changes in present designs. The wrist pin design em­ployed by the Laboratory on these FY 1942 tests gave sood service and appeal­ed to the operators. It was lubricated with grease, however, and if an oil reservoir could be utilized along with oil retaining bronze pins inserted into the wrist pin, it should be superior.

"Auxiliary Research Activities: In addition to the assignments on the crank shaft, crank legs, and bearings, several other research assignments were given attention at Sacaton, Arizona, during the period here covered.

"A high-potential static eliminator was installed about 1-1/2 inches above the roller and doffer on one of the stands in the main gin. No difference was observed in its action when placed over either roller or doffer, and when it was positioned between the two, it worked well in any of those positions, and if the commercial cost of such static eliminator is not excessive, they could be installed in the commercial gins with satisfactory results. When the static eliminator was connected to the electric supply, thus giving a 14, 000 volt high-potential de-ionizing effect in that area of the main tube or elimi­nator, the effect upon the cotton fiber was noticeable at once. The fibers did not carry back beneath the knife (backlash), nor did they adhere to the doffer or metal surfaces of the gin. During static conditions, when the eliminator was shut off, the cotton began at once to cling to the roller and to metal surfaces, rendering the doffers ineffective and giving other operating troubles. With this type of static eliminator, the lint flue and doffers seem to be given better chances for successful operation.

"Desert type of air conditioners were installed in the windows of the roller gin by the engineers, and these raised the humidity of the ginning room appreciably. It is possible that since the roller gin rollers heat up during operation, and may hereby increase the static trouble, that the rollers could be cooled by some system which uses moist air. ASsistance of the engineer­ing physicist is necessary in such devices.

"Seed grids on roller gins are also needing improvement and develop­ment. At Stoneville, three test grids were made up from bar steel and 3/ 16­ inch fingers welded thereto. Spacings of these fingers were 5/16, 3/8, and 7/16-inch apart respectively, giving a smooth rounded discharge port which J.S. Townsend recommends for such work. Several ideas on seed grids have come to mind in this work. First, a seed grid might be made with 3/8-inch spacings and with alternating fingers bent down so that the ends of the seed grid would give more space for the seed to fall through. Such a grid should be placed quite close to the moving knife, and the amount of the depression of alternate fingers found out by testing, bringing the bending to a point where seed cotton leakage through the space was imminent. A horizontal belt with barbs could be placed below the grid so as to return any cotton that had leaked through. Possibly no barbs would be necessary if a vertical lift belt had them and the horizontal belt merely carried the cotton over to it. Several other seed grid ideas could also be tried.

"The tests will show what results were obtained from the desert fans. Since the lint flue withdraws a large volume of air from the ginning room, this exhaust air would pass through an airwasher and be returned again or be us e d to condition incoming seed cotton. It is now difficult to meet the extremely dry conditions at these cotton gins, when atmospheric conditions tend to pro­duce static electricity and when conditioned air is not used over again.

"Conclusions and Comments: From the findings and experiences of these FY 1942 tests, the Laboratory can make up better cranks and crank legs. The heavy duty bearings of ring-oiling type appear to be satisfactory. New guards and simpler oiling for the cranks are needed, and are being devised. Better wrist pins and improved lubrication for them is also being worked on. "(End of Report).

In October 1943 at Las Cruces, New Mexico, in cooperative tests at the Las Cruces Roller Gin which has since been dismantled, engineering staff member Ray C. Young began a series of static elimination studies on roller gins, using the two methods of high voltage static eliminator bars and moist­ening systems.

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Plans of high voltage static eliminator bars as setup by Young and Harmond at San Carlos Roller Gin, Casa Grande, Arizona, and also at Las Cruces, New Mexico, during September and October 1943; A, floor plan at San Carlos Gin,.

As an alternative to applying moisture for eliminating static electricity at roller gins, the cotton ginning research engineers resorted to the use of

high voltage static neutralizer bars. In the fall of 1943, Messrs. Young and Harmond made tests of these neutralizer bars at Casa Grande, Arizona, and Las Cruces, New Mexico. Figures 65a and 65b respectively show gin build­ing floor plan of stands and wiring at the San Carlos Gin at Casa Grande and partial side elevation of cotton condenser installation at Las Cruces. In the light of more recent tests than those of 1942, it has been found that such in­stallations are not adequate under all ginning conditions.

Several moisture setups were also used in which Hardwicke-Etter Co. , assisted with some of their steam and water spraydevices as delineated in fig. 43. The Department's steam vaporizer layout for the gin stands is outlined in figure 66.

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Plans for high voltage static eliminator bars as setup by Young and Harmond at San Carlos Roller Gin, Casa Grande, Arizona, and also at Las Cruces, New Mexico, during September and October, 1943; B, condenser wiring where static bars were placed in vicinity of a doffing roller at the discharge.

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When substitutes for expensive walrus hide and other leathers were being sought in the early '30s, the De­partment's research engineers and tech­nologists turned to plied packings. The plied canvas - rubber packings at first employed from 11 to 15 alternating lay­ers of heavy canvas and natural black rubber as discussed in connection with figures 39 to 41. Spool windings of this material frequently produced objectionable stains in the lint because heavy

knife pressures peeled the rubber from between the canvas layers more readily than was possible with spiral winding. About 1948 white synthetic layers began to replace the black natural rubber.

It may be appropriate at this point to say that during the 1930 -44 re­newal of roller ginning activities in the Southwestern States of this Nation, a number of makes and models of roller gins were employed, among which were the following: Platt Bros. & Co., Ltd.; Dobson and Barlow; Liberty; Sultry; Coats; Talley; Armour; Continental; Murray; Hardwicke-Etter; Foss; and Middleton. Many of these were further improved by the late L. A. Brewster, whoinstalled ball bearing cranks and durable wrist pins for the moving knives. These foregoing gins used rollers from 6 to 8 inches in diameter, operating at 100 to 125 rpm, and principally covered with walrus hide or packing ma­terial.

In this same period, crank speeds for the moving knives ranged from 650 to 800 revolutions per minute; and the ginned lint turnout was from 1 to 1- 1/2 bales per gin stand per 10 hours. Ginning Laboratory tests in the South­western states showed at this time that a crank speed of 930 rpm and a roller speed of 150 rpm on 6-inch diameter rollers turned out 34 percent more ginned lint than did speeds of 650 and 125 respectively. It was also found that spool-wound rollers ginned somewhat faster than did spiral wound, but 7- and 8-inch diameter rollers were almost 1/3 slower than 6-inch rollers when operated at the same roller and crank speeds. In other words, the smaller diameter rollers appeared to have greater capacity.

OTHER ROLLER GINNING DEVELOPMENTS, 1930-58

Several roller gin designs of promise have been tendered to the Gov­ernment Ginning Research Laboratories for study. Among these have been the. Cox cone-type roller gin, the Pettit roller gin, and several others. Each has had features of merit, but the trade in general at that time did not see its way clear to pay for higher priced units because of the uncertainties of long staple cotton crops.

Double box presses at roller gins have been slowly replacing the older single box presses. With these have come lint cleaners as well as pneumatic and belt lint handling systems previously mentioned. So far as is known, the U. S. Department of Agriculture's ginning engineers were the first to use lint cleaners on a roller ginning setup, and this was accomplished very, success•• fully in 1952 at Mesilla Park, New Mexico.

Seed handling improvements, common to saw gins, have also gradually found their place in modern roller gins, so that small-pipe pneumatic seed handling may be cheaply and effectively employed.

From 1955 to 1957, the USDA Cotton Ginning Research Laboratories did much experimental work on swastika type revolving moving knives for roller gins, both at Mesilla Park and at Stoneville. Cooperative runs were made also by the White Gin Association at Canutillo, Texas on this type of moving knife. Figure 67 shows the principal features of this idea in which the speed of the rotary or swastika knives ranged from 23.0 to 500 rpm in the tests.

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Reports in detail have been issued by the Laboratory and are not repeated here. Suffice to say, however, that while this design had several good fea­tures in, an increased capacity and sim­plicity of construction there was a con­stant hazard of seed cracking and a wide variability of samples from very good to poor.

Other investigations toward improved roller ginning are constantly in progress, and the Government Laboratories have been trying out a series of new ideas advanced by staff members. Among these ideas is a public patent­ applied-for invention by Agricultural Engineer James M. Williams, Jr., and associates, which is of interest because of its extremely high capacity, namely up to 20 pounds of ginned lint per hour per inch of roller length, or over 400 pounds per hour on a 20-inch roller gin. Figure 68 affords a simple line diagram of the Williams' idea, wherein an endless chain of bar moving knives, having suitable gaps, travels at high speed over the upper surface of the gin­ning roller and fixed knife. Ginned seed and some unginned locks travel be­yond the end of the fixed knife to one point of disposal and reclamation, while the ginned lint travels from the ginning roller downwards in conventional style. Williams has increased the ginning roller size to approximately 12 inches diameter and has worked on other elements toward perfection of the unit. A more detailed description of the Williams' flight-bar gin is to be found in the Cotton Gin and Oil Mill Press issue of August 9, 1958.

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Read more...

What is Roller Cotton Ginning


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by
Charles A. Bennett, Collaborator
(Formerly Principal Agricultural Engineer)
Cotton Ginning Section
Agricultural Engineering Re search Division
Agricultural Research Service
United States Department of Agriculture
Sponsored by
The Cotton Ginners' Journal
and
The Cotton Gin and Oil Mill Press
Dallas, Texas
Part I
COMMERCIAL ENGINEERING DETAILS AND DATES

Primitive and Churka- Type Roller Ginning
Neither history nor archaeology have established when mankind first began to use cotton fibers, but fabrics of cotton are quite definitely known to have been in use as far back as 4,000 years B. C. in India•a.nd probably ser­ved people long before then.
Undoubtedly the first method of ginning cotton was with the human fingers, a method that has continued in use throughout the centuries. This  can hardly be called either roller or saw ginning, but it might perhaps be termed pinch ginning. The second method, believed by the author to have logically followedthe pinch gin­ning, is that of the archaic foot-roller somewhat as depicted in fig. I.
Figure 1.
Old fashioned foot-roller gin, used to a limited extent to this day in the remote areas of India.
In his 1949 report to the National Cotton Council of America,
"Cotton in Pakistan and the Indian Union", Mr. Read P. Dunn, Jr., published this figure which was credited to the East India Cotton Association, Ltd. , to whom we are in turn grateful. The observant reader will note that in this ginning method the women do the work, a practice of the western Indians as well, although the author has not been suc­cessful is putting this into practice at his own abode. Perhaps from this foot-roller idea arose that of the rolling pin and other feminine utensils.
At any rate, Mr. Dunn said that about 10 percent of the Indian Union cotton crop was ginned by primitive churka and foot-roller gins. The churka c. method of ginning, a true roller gin with small diameter pinching rollers that took the fiber from the seed without crushing, has been thought to have been named from Sanscrit whence came the term "Jerky" (which has long been spelled churka).
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There are several types of the small, hand-operated churka gins, two of which are shown in fig. 2a, b, and c The diagrams give approximate di­mensions in inches.
Figure 2a.
A sketch of a double crank gin with two hand cranks and no gearing.
Figure 2b.
Sketch of a single crank churka gin, made from the model ow­ned by the late Walter Going.
The sketch in 2b shows the reproduction of the Hindu churka brought back from India about 1936 by the late Walter Going, Continental Gin Com­pany, Birmingham, Ala. Mas­ter Mechanic Russell G. Mc­Whirter made the replicawhich is on display at the USDA South-
. western Cotton Ginning Re­search Laboratory at Mesilla Park, New Mexico, where the department now centers its rol­ler ginning research. Such a hand churka gin would probably turnout about five pounds of fi­ber in a long day.
It can only be conjectured as to what kind of primitive ginning methods were used in an­cient Mexico, Yucatan, and Peru, as no re­cords or models are available on the subject.
Figure 2c
Photo of a Pakistan small churka gin owned by Alfred M. Pendleton.
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It is a historical fact that, until the invention of the McCarthy gin in 1840, roller ginning efforts and ideas were largely centered about the ancient churka type of gin, and much thought was given by the more progressive cotton growers and merchants toward attaining larger sizes and greater capacities than were feasible in the hand-operated units. Accordingly, the general de­velopment of roller ginning is henceforth listed more or less chronologically in order to present a clearer view of American activities in particular.
1742 - In this year it was reported that M. Dubreill, a French planter in Louisiana, had invented an improved roller gin that had greater length of rol­lers and more capacity than other gins then in use. Unfortunately we have not been able to locate sketches or detailed description of the M. Dubreill gin.
1772 - In the Mississippi-Gulf areas, considerable publicity accrued to a Mr. Krebs of Pascagoula who invented a roller cotton gin having a daily outturn of some 70 pounds of ginned lint, while competing units could only deliver ap­proximately 30 pounds. In a history of Florida, Captain Roman of the British Army was quoted as saying that the Krebs roller gin had foot treadles and two well polished, grooved iron spindles set into a frame approximately four feet high.
1777 - At this time Kinsey Burden of Burden's Island, South Carolina, con­structed a roller gin that was made from old round gun barrels. These rol­lers were fastened at the ends on suitable trunnions, and the unit claimed a daily capacity of 20 pounds. This unit was currently dubbed the "barrel gin," and was said to have been quite popular in the Carolinas, Georgia, and Flor­ida.
1790 - Dr. Joseph Eve, residing near Augusta, Georgia, introduced some form of foot treadle gin into Georgia and was given much advertisement about this time It is not known whether he employed Krebs' foot treadle drive or not. However, we here refer to the Cotton Planters' Manual (J. A. Turner) that came out in 1857 for additional information on the Eve gin. We quote from a statement made by Thomas Spalding of Sapelo, Georgia, under date of January 20, 1844:
"1st. Eve's gin was invented by Joseph Eve, who died lately at Aug­usta, somewhere about the year 1790, in the Bahama Islands, where Mr. Eve then resided.
"Mr. Eve was the son of a Loyalist from Pennsylvania, who had been a friend of Franklin; and Joseph Eve was himself qualified to have been the associate and companion of Franklin, or any other; the most enlightened man I have ever known.
"His gin consists of two pairs of rollers, more than three feet long, placed the one set over the other, upon a solid frame that stands upon the
floor, inclined at an angle of about thirty degrees - so that the feeder may the more easily throw the cotton in' the feedby the handful upon a wire grating that projects two inches in advance of the rollers, just below them; between these protecting wires, the feeding boards, with strong iron, or in preference brass teeth pass, lifting the cotton from the wire grating, and offering it to the revolving rollers. The feeders should make one revolution to every four revolutions of the rollers. The rollers are carried forward by wheels sup­ported over the gin, and upon the axle or shaft of these rollers; at the center there is a crank similar to a sawmill crank, the diameter of whose re­volvement is as one to four of the diameter of the wheels, carrying by bands the rollers.
"It is the crimping produced by the teeth and the wire grating, which has served as a cause for carping by the cotton buyers, and which has grad­ually led to the disuse of these gins, the only gin efficient for the cleaning of long cotton, which has ever been used in this or any other country. With Mr. Eve's gin, as originally sent to this country from the Bahamas, the rollers were 5/8's of an inch in diameter, made of stopper wood, a very hard and tough wood, and they were graduated to make four hundred and eighty to five hundred revolutions per minute, depending of course upon the gait of the hor­ses or mules, within these limits.
"Soon after Mr. Eve sent his gins to Georgia, some of his own work­men followed them, and began to make them on their own account. To show as much change as possible in the gins, besides other alterations, they in­creased the size of the rollers to three-fourths of an inch, and increased its velocity to six hundred times in the minute. These two changes, while they greatly increased the quantity ginned, very much injured the appearance' of the ginned cotton.
"Mr. Eve had expected and guaranteed to the purchasers of his gins when well attended, in fine weather, from two hundred and fifty to three hun­dred pounds of cotton in the day. I have known these altered gins do some­times six hundred, but the injury was greater than the increased quantity warranted, add to which the quicker movement of the feeder made the more impression upon the cotton passing from the feeder to the roller.
"2d. The first bale of Sea Island cotton that was ever produced in Georgia, was grown by Alexander Bisset, Esq. , of St. Simon's Island, and I think in the year 1778. In the winter of 1785 and '86, I know of three parcels of cotton seed being sent from the Bahamas, by gentlemen of rank there, to their friends in Georgia; ;this cotton gave no fruit, but the winter being moderate and the land new and warm, both my father and Mr. Bisset had seed from the ratoon, and the plant became acclimatized.
"In 1788, Mr. Bissett and my father extended the growth, but upon my memory it rests, that Mr. Bissett was the first that found the means of sep-
arating the seed from the cotton, by the simple process of a bench upon which rose a frame supporting two short rollers revolving in opposite directions, and each turned by a black boy or girl, and giving as a result of the day's work five lbs. , of clean cotton."
1827 - Although there seems to have been little doing in roller gin improve­ments in the United States until this time, it was reported by William Elliott of Beaufort, South Carolina, that foot treadle gins (see fig. 3) had superseded the earlier kinds of churka gins, and that the treadle gins were being impor­ted from the West Indies at about ten dollars ($10) per unit.
Figure 3.
Author's diagram of one form of a foot treadle churka-type roller gin. having heavy fly wheels on the top roller shaft. Other forms than this probably have been made with the two flywheels, but one being placed at the• end of each roller, in which condition the flywheels would then revolve in opposite directions and necessitate care in starting.
Referring back to the quoted article written by Mr. Thomas Spalding under date of January 20, 1844, it may be remarked that his statement is not very clear as to who unveiled the first gin, Eve or Bissett. He says that Eve's gin was the best ever, yet follows that with the declaration that Mr. Bissett was the first man that found the means of separating the seed from the cotton. If so, several centuries passed very rapidly between the time of Mr. Bissett and Mr. Eve, because we know the churka gin is ancient, and Mr. Spalding describes a churka gin perfectly when he tells about Mr. Bissett's.
It is no wonder that a dollar went further in those days, if a man could buy even a churka gin stand for ten American dollars! Elliott said in one of his writings that tapered hardwood rollers were paired together (presumably tapered from about 5/8-inch diameter at one end to 1-1/4 inches at the other and that with speeds well above 100 revolutions per minute the daily ginning capacity reached approximately 30 pounds of ginned lint.
In reviewing these various statements, it seems that some ginners made up as many as five pairs of either the Eve or gunbarrel rollers per gin­ning unit, and that when these five pairs were used, the daily outturn was about 135 pounds of lint; but the competing Whitney saw gins were delivering 2 pounds
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per saw per hour on 8-inch diameter saws, so that in a day one Whitney type saw gin delivered from 600 to 900 pounds of ginned lint according to the re­ports of various papers and writers. However, the mills, mostly in England, seemed to prefer roller ginned cottons when they could have their choice be­cause there were fewer neps.
1835-1839 - William Whittimore, Jr. , of West Cambridge, Mass., began to attract attention with his roller gins. He obtained one patent in 1834 and an­other in 1839. Figure 4 shows the main elements of these inventions in items a, b, and c. The Charleston, South Carolina, Mercury of 1835 made favor­able note regarding his gin.
Figure 4.
W. Whittimore, Jr., roller ginning inventions: a and b, features of his 1834 patent in which he employed a belt and squeeze rollers as the assisting agents in ginning; and c, the side elevation of his 1839 invention, where he used one roller made of leather disks, and the other made of roughened metal.
1838 - In this year an old maestro in the ginning world tried his hand at the subtleties of roller ginning, the maestro being none other than Eleazor Carver who had moved from Washington, (near Natchez) Mississippi, to the manufac­turing centers of East Bridgewater, Mass. Carver had a rather clever idea in using spiralled rollers in pairs, virtually similar to gears, so that they could be fed on a flat plane for several pairs of rollers, and so that the seeds would be angered to the ends of the rollers whilst the ginned lint went down to a traveling belt. Figure 5 (on the next page) delineates in sectional form the Carver invention.
The shop construction of such rollers would have been difficult in many of the machine shops of that period, and the author has been unable thus far to loc­ate models or reports of commercial use of this Carver gin.
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Before taking up the most important roller gin invention of the century, that, of Fones McCarthy in 1840, two other inventions should be mentioned; namely, those of Richard Reynolds, Beaufort, South Carolina, and Theodore Ely, New York, New York.
Cross-section of Model 1838 Car- Reynolds 1844 roller gin: an isometric
ver roller cotton gin, which was view and a cross section, wherein
not limited to the number of pairs B and C were the ginning rollers and
of spiral meshing rollers, al- 13 did the clearing of the ginned fiber
though only two rollers are shown by taking it fromRoller B. The hand
here lever or crank is not shown here.
The Reynolds roller gin was primarily a triple roller churka type of gin having the two pinching rollers ahead of a special larger clearer roller, all as shown in figure 6.
The Ely invention displayed some genuine mechanical ability, since it comprised both feeder, ginning rollers, and clearers, as shown in figure 7.
1845 model Ely roller gin. This unit em­ployed a feeding cylinder, F; a fanning or direction cylinder, A; two fluted rollers B for ginning;and two clearers or strippers,
D. Counterweight .H provided self-adjust-
ment of pressures between ginning rollers .
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THE Mc CARTHY (or Macarthy) ROLLER GIN AND ASSOCIATED INVENTIONS
On July 3, 1840, a roller gin patent was issued to Fones McCarthy, Demopolis, Marengo County, Alabama, that revolutionized the ginning prac­tices throughout the world and especially in some countries foreign to the U. S. This new type of roller gin which his invention provided became as popu­lar in most countries as the Whiteny saw gin was to our nation. The British refer to the gin as the Macarthy gin, but it sounds the same regardless cf spel­ling.
This, first patent, No. 1675, was followed by others of McCarthy, such as re-issue No. 262 of April 18, 1854; re-issue No. 1675 dated 1856; and No. 67,327 dated July 30, 1867.
In figure 8 is given a cross-section diagram of the first form of the McCarthy roller gin.
Cross-section of the 1840 McCarthy roller gin which revolutionized roller ginning by the use of a fixed blade (sometimes called a doctor knife ) held tightly against a ginning roller, and having a moving knife which co­operated with the roller and doctor knife inperformingthe separation of the fiber from the cotton seeds.
There were several other names for the parts. The moving knife, as we now call it, was termed a hacker blade because it seemed to hack at the seed which were held between the ginning roller and the fixed knife or doctor blade. The single McCarthy ginning roller was much greater in diameter than churka type rollers and hence had greater capacity from the start. Its porcu­pine-like surface seized the fibers and drew them between roller and fixed blade so that there was a constant pull against the seed in order to make a clean separation. McCarthy's first moving knife had fine teeth on its working edge and was called by him the saw.
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The McCarthy roller was made up of coarse leather, grooved to per­mit motes and other unyielding matter to pass the knife without injuring it. He also had a stripping comb behind the ginning rolls, but interposed small float and delivery rolls between the ginning roller and this comb. From what we can ascertain, the first McCarthy gins used rollers that were about 4 in­ches in diameter and 3 feet in length. By 1850, however, the rollers had been increased in size to almost 7 inches diameter and their lengths shortly there­after became standardized into 3 sizes; namely, 40, 60, and 72 inches. Single roller McCarthy gins stayed at 40 inches in length almost universally until the 1940 era of new roller ginning practices began in the United States. Double rol­ler gins became popular, too, and these adopted longer rollers ranging from 60 to 72 inches in most cases. Other improvements in the popular McCarthy type roller gin brought about the reciprocating pusher board, the vibrating grid for shedding seeds, the first sort of rock-and-roll link between moving knife crank and a secondary center to facilitate cleerance and afford better action in ginning, and the revolving stripper roller to wipe ginned lint from the roller.
For years, however, a stationary brush stick or plain scraper bar combed ginned lint from the roller and was popular because of its cheapness. Figure 9 gives a section through the conventional gin of 1900 that was sold in­ternationally by many well known firms.
Cross-section of McCarthy roller gin as of 1900, drawn by Professor D. A, Tompkins and lettered by author; A, main section through roller gin; and B, enlargement of the roller, moving knife, and other ginning elements employed in the 1900 McCarthy model.
Figure 10 on the next page, is a photo-reproduction from sales catalog literature that is representative of almost all better makes of the McCarthy type roller gins in the 40 inch single roller size between 1900 and 1930. American and British manufacturers had also gone to the making of double roller gins.


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A, delivery side (with hopper removed) of an American McCarthy type roller gin; and B, front or feeding side. Courtesy of the Continental Gin Company.
The British Middleton model of double roller gin retained the shorter roller that was virtually interchangeable with single roller gins; but the American Foss model double roller gin generally used 60-inch rollers. The approximate overall dimensions and characteristics are delineated in the plain line sketches of figure 11.
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Double roller cotton gin of the McCarthy type: Figure Ila, American made 60 inch "Foss" sea-island gin. The diagrams and dimensions were taken from research units of the U. S. Department of Agriculture Southwestern Cot­ton Ginning Research Laboratory, Mesilla Park, New Mexico.
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Double roller cotton gin of the McCarthy type: Figure 11b, British-made 40 inch Middleton gin. The diagram and dimensions were taken from research units of the U. S. Department of Agriculture Southwestern Cotton Ginning Re­sea.rch Laboratory, Mesilla Park, New Mexico.
Much could be said about the advantages and disadvantages of the Mc­Carthy type roller gins which have been in almost world-wide use for many years. They have usually been lower in cost than saw gins and have been more readily operated by unskilled labor, and on all varieties and staple lengths of cottons, regardless of whether the cottons have smooth or fuzzy seeds.
Saw gins, on the other hand, are not universally adaptable to all cot­tons. They have not served well in ginning sea-island or American-Egyptian long staple cottons, and their ginned lint has met with objections from the cot­ton mills. They blend the cotton fibers much better, however than do roller gins.
Capacities of the McCarthy type roller gins are usually far less than saw gin stands of equal floor space. For example, in the United States a rol­ler gin usually produces from 1 to 1-1/2 pounds of ginned lint per hour per inch of roller length or from 60 to 90 pounds for a standard 40-inch roller length; while a saw gin having 12-inch diameter saws will deliver 9 or more pounds of ginned lint per hour for each inch of the saw cylinder net length, since the saws are usually set on approximately 3/4-inch centers. Thus, a saw gin has about 5 to 7 times greater capacity than a roller gin of equal length.
Small McCarthy type cotton gins for laboratory use and cotton genetics work usually are to be obtained in 8-, 12-, and 16-inch roller lengths. Figure 12 on the next page illustrates a British made 12-inch roller gin, and figure
13 shows a cross - section view of the late J. S. Townsend design which is used for governmental purposes in both 8- and 16-inch roller lengths.
Figure 12.
Hand roller gin with 12-inch roller. Courtesy of Platt Bros. , Ltd. , Old­ham, England.
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In setting up American roller gins between 1900 and 1930 it was custo­mary to frame a row of vertical heavy timber posts to provide bracket supports for the feeders and shafting hangers. Figure 14 is a line drawing showing such a typical gin stand and timber set-up.
End elevation diagram of roller gin stand, draper feeder, overhead feeder, and timber posts as used at roller gins. Courtesy of the Murray Company of Texas, Inc.
Interesting factory line isometric drawings of 1917 are shown onthe next page to indicate the type of roller ginning equipment that was generally used during the period of World War I. The three figures, 15a, 15b, and 16 were lifted from the repair handbook of The Murray Company by the author
who deleted numerals in order to make small size illustrations for the pur-
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pose of this report.
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Isometric sketches of McCarthy roller gin stand and feeder, 1917 model units; A, the gin stand proper; and B, draper or spiked belt feeder that was usually interposed between the ginning roller and the overhead cleaning feeder to give more uniform and slower feeding at the working zones. Courtesy of The Mur­ray Company of Texas, Inc.
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Figure 16.
Isometric sketch of 1917 model over­head small drum cleaning feeder as used in ginning Pima cotton. Cour­tesy The Murray Co. of Texas, Inc.
Since the floor plans of roller ginning establishments have varied a great deal, they will be shown in a later sec­tion of this article. However, views indifferent roller ginning plants that operated between 1930 and 1950 are here shown in figures 15 to 17 inclu­sive.
In most of these ginning plants the heavy vibrations of the roller gins
necessitated sturdy sills set into concrete at ground level. Cleaning and other auxiliary machinery has likewise been kept as low as possible, although balcony installations of smaller extracting and cleaning units are compara­tively common.
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From previous descriptions of the older roller gins of the churka type, it is evident that they were either hand or foot operated. Oriental McCarthy type roller gins have also been similarly powered, and for smoother operation the treadle gins of all kinds seemed to be forced to the use of heavy flywheels. However, very small churkas and the present day laboratory gins may be ob­tained for hand drive or for electric motor propulsion. The motors have usually ranged from 1/4 to 1 h. p. for roller lengths that vary from 8 to 16 in­ches.
In the United States limited water power provided means for cotton gin propulsion at a few fortunate locations, but steam engine drives became com­mon until the supply of wood became scarce or other fuels became too expen­sive, after which electrical and internal combustion engines took over the field. However, natural gas and fuel oils were and still are being used at some steam-powered gins where steamboilers are retained for various reasons.
A few steam-driven threshing engines served to run small cotton gins, while both portable and stationary internal combustion engines of various kinds have been pressed into service. Farm tractors also still provide temporary power for some of the smaller cotton gins in the United States, although such roller ginning establishments are few in number.
Power requirements for commercial McCarthy type gins vary from 5 hp. for a 40-inch roller gin stand plus small drum feeder (refer to figure 14) to as much as 25 hp. per gin stand unit in larger roller ginning establishments that utilize extensive accessories and auxiliary equipment. A simple rule of thumb applying to a roller gin stand only is, for commercial gin, to allow 1­14 hp. for each lineal foot of roller length in the stand, plus 1/2 hp. for each spiked belt draper feeder (refer to figure 15b). Power consumption of other ginning auxiliaries such as conveyors, fans, separators, driers, cleaners; extractors, lint cleaners , and presses are tabulated in cotton ginners hand­books or obtainable from the manufacturers of ginning machinery.
The principal elements of the McCarthy designs that revolutionized roller ginning have already been set forth in Figure 9; namely, 1, the ginning roller; 2, the fixed knife whose working edge bears heavily against the ginning roller at its axis centerline; 3, the reciprocating moving knife which has an arcuate stroke across the working edge of the fixed knife; 4, the seed grid; 5, the pusher board for feeding seed cotton against exposed roller surfaces be­tween the movingknife strokes; and 6, the doffer which clears ginned lint from the ginning roller surface.
Between 1840 and 1900 a surprising number of patents were granted on improvements suggested for one or 'more of these major elements in addition to the patents that have been listed for McCarthy himself. These inventions endeavored to overcome some of the roller ginning troubles such as the des­tructive vibration of unbalanced moving knives, difficulties in adjusting and
maintaining overlap and clearance settings, ginning roller bending or lack of stifiaess, Short life of roller covering, and seed crushing or chipping.
A few of the inventions prior to 1900 will be only briefly mentioned without illustrations. From 1900 to 1957 we have more fully described and illustrated the inventions that are deemed to be of significance as contributing to the field of roller ginning. Foreign inventions and patents are note fully covered because of the lack of reliable information.
1861 - James F. Furguson, Miconopy, Florida, advanced ideas for improved rollers by using spiral winding, together with better ginning by having a more adjustable fixed knife and a vibrating moving knife whose working edge corn-, prised a row of alternating long and short comblike teeth. From that time on some roller gin inventors began to toy with all three ideas in different ways.
1862 - 1881 - The following list of roller gin patents is givenfor references without description because they do not seem to have introduced significant • changes in the arts of roller ginning.
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And, second, he made up a 4-bladed stripping roller or doffer to operate ad­jacent to the ginning roller. The blades were at right angles to the rotation. It may be that these disclosures led to rather wide adoption in foreign coun­tires more than in the United States because Egypt in particular had plenty of soft leather from their water buffaloes.
1892 - J. R. Montague et al, Syracuse, New York, went back to rather elab­orate churka roller ginning ideas in their design, using a vertical pair of small and large rollers, a fan suction, and several other elements, making the unit quite complicated. This patent, No. 485,015, was issued. October 25, 1892, and was granted 15 claims. No reports are available as to whether a roller gin was actually constructed in line with these designs.
1894 - D. F. Goodwin, Valdosta, Georgia, made a design for a double roller gin in which one roller was placed above the other, but employing the standard McCarthy reciprocating knife and other conventional features. For reference, it may be noted that he was granted U. S. Patent No. 530,941 on December 18, 1894.
1895 - Although other inventors seem to have tried out segmental moving knives on long roller McCarthy roller gins, J.E.Coleman was granted a patent on one phase of the idea.
1895 - J. Daig, Gainesville, Florida, brought out an important improvement in fixed knife adjustment for McCarthy type gins. His invention was that of using two special springs that would hold the fixed knife firmly against the rol­ler at fixed pressure. This idea was tested at the U. S. Department of Agri­culture Cotton Ginning Research Laboratory, Stoneville, Mississippi, and was found to have considerable merit. A pressure of 30 pounds per inch of fixed knife against the roller gave optimum results. Martin, Townsend, Walton, and Baggette conducted most of the tests during the years 1941-43.
1895 - S. L. Johnston, Boston, Mass., designed a roller gin that was up­-
side down to the McCarthy conventional design. He reversed the position of
the fixed and moving knives and added a sort of comb at right angles to the moving knife blade on the cotton feeding side so, that it would stir up the seed cotton better.
1899 - J. W. Graves, then a resident of Little Rock, Arkansas, designed a multi-roller gin. However, his radical design will be illustrated in the 1900 group to follow.
1900 - In this year J. E. Cheesman, New York, New York, organized the Cheesman Cotton Gin Company to promote his several roller ginning inventions and designs. He brought out a single roller gin stand on these patents- about 1902 for public use. This unit was rather highly publicized. In it he had re­versed the position of the knives as was done by Johnston in 1895, but he went all out for eccentrics in place of cranks, and he employed a whole series of
relatively short, eccentrically driven moving knife segments in lieu of one blade. Along with this, design of gin stand, which had cast iron end frames and was largely of metal otherwise, Cheesman used a small-drum cleaning feeder with regulated flow of seed cotton. The feeder was not a basket type that came later for saw gins but was an almost 25-year advance over other feeders then being built.
The Valdosta (Georgia) Times, under date of July 18, 1902, was quoted in some advertising pamphlets as saying that 32 of the Cheesman gin stands were being installed at the Valdosta Ginning Compahy which would then be the largest American Roller Ginning Establishment and that it would be able to gin out more than 100 bales of sea-island cotton per day.
About 1909 Cheesman delivered a special address to the American Cot­ton Manufacturers' Association in which he detailed a cross-section design of his improved roller gin being manufactured under the 'name of Empire Du­plex Gin. The construction of this second unit of his is shown, in part, by the diagram section given in figure 22.
Figure 22.
Sketch depicting a cross-sec-
tion of Cheesman's Empire Du­plex Roller Gin, showing the rotary comb moving knife inlieu of his segmental reciprocating blades in the 1902 design.
Inquiries have not yet revealed whether there are any of either of the Cheesman rol­ler gins in existence at this late date; but his feeder de­sign and the use of eccentrics were a practical improvement over previous practices.
A reference to fig. 22 will also indicate another far -sighted improvement of Chess­man's that lapsed into obscurity for many years. It was his use of large steel pipe cores for the foundation of the roller wood and covering.


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This design would not only eliminate buckling and whipping at higher speeds but also would materially stiffen and strengthen long rollers. With such de- Sign the shearing of drive shafts onithe rollers could be easily overcome.
Also in 1900 an active figure in roller gin design was Matthew Prior, Watertown, Massachusetts, who used the upside-down McCarthy idea but, ex­perimented over several years with metal ginning rollers and oscillating mov­ing knives of the comb type. One feature that he patented. in 1900 was that of an agitating feed bin, at the bottom' of which was a reciprocating comb. knife. These and other items are shown in the diagram of fig. 23. Among the several roller gin patents that Prior obtained, one that is described for the year 1911 may be ofinterest.
Figure 23.
Diagram section of Matthew Prior Is 1900 model raler gin, having an eccentrically driven hopper side with moving comb knife at the bot­tom, a rotating clearer or agitating cylinder with stub paddles, a fixed knife placed in an almost horion­tal plane, and a seed grid opposite the clearer.
During 1900 3. W. Graves, who seems to have moved from Little Rock, Ark., to Covington, Tenn.,
between inventions, introduced a
novel idea for roller gin construction by using hinged knives so that the fiber
could be blown between them and the ginning rollers at timed intervals or bites. Graves did not use a rotating or reciprocating moving knife for push-
ing the seeds from the doctor blade (another name frequently used for the fix ed knife, but he did use small perforated rollers above the ginning rollers, and he operated the hinged blades by exterior cams. Figure 24 is a diagram sec­tion of the Graves roller gin idea.
As the entire gin stand of Graves was somewhat elaborate the reader is referred to U. S. Patent No. 655, 734 issued September 11, 1900, for fur­ther details. Although figure 24, shown on the next page, does not indicate some features of Graves' invention, it is well to call attention to the fact that the bites of his hinged blades were in sequence, depending upon how many rollers were used, and that the seed cotton entered into the main hopper through a sealed wheel so that air pressure might be exerted through the perforated", small cylinders and blade gaps.
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Figure 24.
Model 1900 Graves duplex ,roller cotton gin shown in cross-section diagram to illustrate the principle Ei employed.
1901 - At San Antonio, Texas, W. H. Wentworth submitted as his invention a fully vertical, roller cot­ton gin. In. his design he used six vertical ginnin rollers, six ver­tical fixed knives, and six vertical knives that reciprocated horizon­tally to reproduce the conventional McCarthy action, plus other verti­cal elements such, as frames, chu­tes, and the like. \A. central core supplied seed cotton to each ginning compartment, and all moving elements were propelled by internal and external gearing located about the circular casing.
The patent figures indicate a roller gin of size suitable for laboratory use, but with sufficiently. large gears it would have been possible to make a 6-roller ginning unit in relatively small floor space. Since a suitable illustration of this invention is not available for reproduction here, the reader 'is referred to U. S. Patent No, 668,470 issued February- 19, 1901. 'It is believed that the Wentworth roller gin is the only vertical gin of its kind on record.
1902 - C. J. McPherson, South Framingham, Massachusetts, devised a very elaborate roller gin combination that is partially depicted in the two sections given in figure 25. This invention was the first of several duplex roller gins along this general order.
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However, McPherson evidently had the spinning mill practices in mind because he sought to convert each roller gin stand into a combination of spinning mill blender, airborne feeder, and gin­ned lint belt conveyor all in one which would have been, in cost at least, out of the reach of most commercial roller gin operators.
1903 - Multiple roller gins were by this date no novelty although the records show very few conventional McCarthy gins having more than two rollers . How­ever, A. M. Dastur, Jalna, Hyderabad, India, invented a 4-roller gin stand and obtained an American patent on it When viewed from the end of the gin stand, his rollers were positioned in a sort of vee relationship so that all four moving knives might shrug on a common rocker assembly. Overlap had to be the same for all four fixed knives, and to obtain satisfactory distribution of the cotton to all rollers Dastur employed small kicker rollers, one on each side at the top of the common cotton hopper that lay between the vee form of rollers. In case the reader is interested further in this Indian patent, he is referred to U. S. Patent No 736, 227 issued August 11, 1903.
T. Brandon, New York, New York, during 1903 obtained a patent (No. 731, 273) on a roller gin that used eccentrics in lieu of cranks for the moving knife, and he employed a sliding stripping comb across the face of the moving knife. As several other inventors have presented ideas somewhat along the same lines, some of these will hereinafter be mentioned and illustrated.
1910 - J. C. Boesch and J.H. G. Von Oven, Charleston., South Carolina, in­vented an ingenious combination of moving and fixed knife for their roller gin, which also had a metal roller with diamond grid indentations on its surface as shown in figure 26. The sliding moving knife reciprocated sideways along the fixed knife.
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Plan view of Boesch model 1910 roller gin with side details of the knives, and roller. Collar button type of retainers held the sliding serrated moving knife in alignment along the surface of the fixed knife. This gave a mowing machine action, so to speak, for the serrated knife. The inventors claimed that the diamond indentations readily seized the cotton fiber.
1911 - Matthew Prior, Watertown, Massachusetts, was previously mentioned for his model 1900 roller cotton gin. In 19.11 he constructed models and ob­tained a patent on an upside-down arrangement of the McCarthy type roller gin, the position of the knives being reversed so that the moving knife reciprocated downwardly from ove rhe ad . In place of a straight blade moving knife, however, he employed the comb type for which he claimed much in actual practice. The model of this invention is now at the Southwestern Cotton Ginning Research Laboratory, Mesilla Park, New Mexico, where the United States Department of Agriculture conducts the roller ginning research. In 1938 when the author had the pleasure of visiting Mr. Prior, who was then almost 80 years old, he learned of Prior's roller ginning activities in the Orient. Prior claimed that bronze rollers with a fine-grained roughness were the best constructions he knew of, but he had obtained excellent clingability for roller surfaces by using alternate layers of grass cloth or haircloth fabrics and canvas pressed into strips somewhat like pump packing and then wound spirally around the roller. Prior also used a 4-flap rubber doffer to remove the fiber from his ginning roller. A small Townsend 8-inch Government model roller gin, obtained about 1941 by Deane Stahmann of Las Cruces, New Mexico, was turned upside down
Prior fashion, and it has been claimed to do very fast and good work.
1913 - S. D. Shepperd, Neward, New Jersey, came out during this year with a very well designed duplex roller gin whose cross-sectionis shown in fig. 27. In. this design Shepperd used rotary moving knives that were constructed of 3-tooth washers which were strung and keyed to their shafts. Plain washers of small outside diameter were placed between the toothedknockers so as to give a combing action as well as a moving knife separation of seed from fiber.
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Section through 1913 model Shepperd duplex roller gin. Note the duplex seed grids and rotary moving knives at each side of the section with the lint flue central.
The Cheesman gin of fig. 22 had a similar form of rotary knife, as did McPherson's 1902 duplex model.
1914 - To obtain better balance and moving knife action, E. G. Trepani, of Liverpool, England, and Adana, Turkey, obtained a U. S. Patent on his idea of using double segmental moving knives to which he added a secondary thin set which oscillated sideways between a heavier moving knife and the fixed knife. He claimed a better balance and a double ginning action.
1917 - The elaborate designs of W. T. Dodd, Brooklyn, New York, during
1917 added another duplex roller gin that could be classified as being of the McCarthy type but which differed from previous inventions such as those of Graves and Shepperd. Dodd, like Cheesman, used a cleaning feeder, but here it was a dual cylinder unit and fed down upon a splitter to serve two rollers. Knocker-type rotary cylinders served as moving knives, and an air blast from beneath the ridge served to keep the fiber stripped from the ginning roller and directed downwardly into a dual gin flue system where the lint was conveyed pneumatically to the press. Figure 28 gives a cross-section of the Dodd unit which will be readily understood.
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1922 - Although we have no suitable illustration of the in­vention of W. W. Conway, Hum-bolt, Arizona, it appears that he invented a churka type of rol­ler gin that was somewhat sim­ilar to the Whittimore 1835
model as he depended upon a belting surface and rollers to do the ginning. However, he had a horizontally raking spreader to keep the seed cotton uni­formly spread at the gripping point of the belt and roller. Conway was issued U.S. Patent No 1,408, 343 on February 22, 1922. While his gin probably did not have the capacity of the conventional McCarthy, the design would seem to be superior to an orthodox churka roller gin.
Also in 1922 James C. Garner, Houston, Texas, well known for his regin and other cotton machinery inventions, was granted a patent on a very interesting principle of roller ginning that utilized suction in its operation. Figure 29 gives a diagram section of the principles advanced by Garner for this gin. The diagram will show that the action centered upon a perforated roller through which the ginned lint passed enroute to the gin flue. Below the center­line of this ginning roller Garner placed his fixed knife and diagonally above the fixed knife he reciprocated horizontally a comb form of moving knife. If and when ginned lint did pass through the walls of the perforated ginning roller, it was pneumatically carried to the ends of the roller and there discharged in
an auxiliary flue to the main lint stream. Although the author enjoyed many contacts with Mr. Garner on re-ginning and other problems, he was not in­formed as to whether this suction roller cotton gin was put into field use for any length of time. It is probable, however, that it was thoroughly tested by Garner because he was a practical ginner and ginning designer who was not content to leave his inventions in a paper stage.
1923 - H. E. Werner, Houston, Texas, followed Garner with another form of suction roller cotton gin on which he obtained U. S. Patent No. 1,452, 667 that was issued April 24, 1923. This patent specification gives a voluminous des­cription, illustrated by 28 figures, but there has been no record of its use by the trade. The designs show a built-in fan, hollow perforated suction rollers to grip the fibers so that a fixed knife would do the work without need for a moving knife. No figure is available for this invention.
1924 - H. Cross and A. Korosinki, Naberth, Pennsylvania, were in this year the Patentees of a very unique design of roller gin. In general it followedthe McCarthy principles, but it employed a cylindrical moving knife of zig-zag cuffs on a central tube, much like the sleeves of the French dandies in the time of the Three Musketeers. The fixed knives were sections, built up to make one rigid unit, and the ginning cylinder was of rigid design being formed upon a central pipe with wheel and spoke ends. Two details have been here shown as parts of fig. 30 in an effort to convey the major details of this peculiar roller gin. A special feature of this invention seems to have been the roll-box action that would be obtained by the zig-zag disks which formed the moving knives. These were spaced apart by cast washers having the same contours so that pockets were formed between the disks wherein seed cotton could be carried around until fully ginned.
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1925 - As a sort of unclassified form of cotton gin that was stric­tly neither roller nor saw, but de serves mention at this point, is the 1925 posthumous patent gran­ted to the estate of W.E. Collins, of Houston, Texas. Mr . Collins used two large grooved drums arranged so that an endless wire could form upper and lower grids between the two. These wires ran approximately 3/16 of an inch apart. The lower plane of wires were fed seed cotton frombetween the drums. This seed cotton was then carried toward one drum where the seed were pinched out between the wires while the fibers were gripped in the drumgroove s.
On the upper and outer surfaces
of the ginning drum, final separation took place between seeds and ginned fiber and the mechanisms. (U. S. Patent No 1, 547, 164 dated July 28, 1925).
1928 - As the state of Arizona has long been an intermittent producer of long staple cottons, its roller ginning history has likewise risen and fallen into activities and idle seasons that were not conducive to rapid improvements in roller ginning processes, even if it at times did lead therein. The roller gin invention of Gus Talley (U. S. Patent No. 1, 678, 794 of July 31, 1928) marks an interesting development. In addition to reversing the conventional position of the fixed knife, Talley brought out a cycle-bar or mowing-machine type of crank-driven knife that moved horizontally along the face of the fixed knife, as did Boesch. The machine design was of high grade craftsmanship and the re­latively high cost of the ginning unit may have precluded its extensive use be­cause the claims for its improved operation seem to have been numerous.
Neither photo nor suitable drawing is now available for illustrating this gin, but information has been given that there is a complete Talley gin in existence at Phoenix, Arizona.
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