introduction to ginning process, saw and roller gin

1. Operating Cotton Ginning Machines and Control
Bale Press Operations
1. Introduction to ginning
Ginning mill separates cotton fiber from the seed bolls and dust
particles.
Depending on the capacity the Cotton Ginning Machine – it can
process from about 12 bales per hour to 60 bales an hour.
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Foreign matter levels in seed cotton before gin processing usually
range from
1% to 5% for hand harvested,
from 5% to 10% for spindle-harvested,
10% to 30% for stripper-harvested cottons.
The level of foreign matter dictates the amount of cleaning needed
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3. The quality of ginned fiber is directly related to the quality of the
cotton before ginning.
High grades will result from cotton that comes from clean fields.
Lower grades will result from cotton that comes from grassy,
weedy fields in which poor defoliation or harvesting practices are
used
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4. Sequence of ginning machinery
Feeder & pre cleaners
Feeders
• Gin machinery operates more efficiently when
the cotton flow rate is constant.
• The automatic feed control providing an even
flow of cotton to the gin’s cleaning and drying
system.
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5. Gin pre-cleaners machines
Green ball traps
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.
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6. Principles of green ball traps
• Green boll traps use sudden changes in flow
direction and/or reduce air velocities to
separate heavy foreign materials from seed
cotton
• Generally, removed by inertia force
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8. 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. At low moisture, fibers
are easily broken.
For most conditions, cotton should be ginned at 6
to 7 percent lint moisture. Practically all of the
gins are equipped with at least one stage of seed
cotton drying and most ginning systems have two
stages.
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9. …cont…
• 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.
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11. Cylinder Cleaners
• Cylinder cleaners consist of six or seven
revolving spiked cylinders that turn about 400
rpm.
• These cylinders convey the cotton over a
series of grid rods or screens, agitate the
cotton, and allow fine foreign materials such
as leaf trash and dirt to fall through openings
for disposal.
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12. • In many gins, two cleaners are installed in parallel
with each one cleaning half the seed cotton.
• Principles of cylinder cleaners
• Cylinder 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).
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14. Stick Machines
• The stick machine was developed to remove the
extra foreign matter taken from the plant by
mechanical harvesters.
• 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 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.
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16. Extractor-Feeders
• The primary function of an extractor-feeder is to
feed seed cotton uniformly to the gin stand at
controllable rates.
• 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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18. Gin Stand
• The gin stand consists of a set of saws rotating
between ginning ribs. 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.
• The actual ginning process (separation of lint and
seed) takes place in the roll box of the gin stand.
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19. • 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.
• It is then conveyed to the next machine in the
ginning system, usually a lint cleaner.
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21. Lint Cleaners
• Gins typically use two types of lint cleaners, air jet
and saw.
• The air-jet lint cleaners are directly behind the gin
stand and use centrifugal force to remove trash from
the lint as it makes a sharp turn in the duct work.
• In a saw-type lint cleaner, a condenser removes the
fiber from the conveying air stream and forms it into
a batt.
• The batt is fed to a saw cylinder which normally
rotates at approximately 1,000 revolutions per
minute.
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22. • Lint cleaners remove leaf particles, motes,
grass, and bark that remain in cotton after
seed cotton cleaning, extracting and ginning.
• Most gins that process machine-harvested
cotton have one or more stages of lint
cleaning
• Lint cleaning generally improves the grade
classification (colour, leaf, and smoothness) of
the lint.
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The most common lint cleaning
sequence for roller ginned cotton
A typical saw type lint cleaner which
removes trash & blends & comb fibers

24. Bale Press
• Cotton must be baled and packaged to protect it
from contamination during transportation and
storage
• Bale coverings and ties should meet the
specifications developed by the Joint Cotton
Industry Bale Packaging Committee.
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26. Operating Cotton Ginning Machines
1. Prepare workstation
 Identify and assess all necessary machine parts settings and preparation
for machinery operation in accordance with specification and workplace
standard procedures
 Check Seed cotton for moisture content according to workplace
procedures
 Record and report Non-conforming materials
 Kept clean area around the machine during setting and loading as per
standard and safety procedures
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27. 2. Operate cotton ginning machineries
Start ginning machines in accordance with workplace
standard
Clean and maintain work area around machinery
Stop or shut down machines in accordance with all OHS
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28. 3. Operate bale or mote press
Start press machinery in accordance with workplace standard
Monitor the feed of lint in the lint slide to the press
Feed bale tie system in accordance with manufacturer procedures
Clean and maintain work area around machinery
Stop or shut down machinery in accordance with all safety and
workplace standard operating procedures
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29. 4. Carry out operator maintenance
Identify and report minor running problems in accordance with
workplace and machinery manufacturer procedures
Report major machinery or product faults
Perform minor maintenance and cleaning in accordance with
manufacturer specifications
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30. 5. Dispose of waste materials
Keep waste to a minimum through correct application of
workplace run out procedures
Recycle waste where possible
Machine waste is disposed of in accordance
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31. 6. Monitor product quality
Identify and apply quality requirements for cotton ginning
correctly for all stages of the process
Monitor cotton flow to meet enterprise standard
Check cotton quality visually continuously to ensure standard
Recognize, isolate and report any deviations from normal
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32. 7. Communicate process information
Complete records and other documentation clearly and accurately
where required
Transfer information regarding production status or problems
accurately between changes in shifts
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