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A cylinder cleaner then removes the leaves and other small trash
from the seed cotton by shaking it with spiked cylinders, while
conveying it across a screen with small openings that sift the trash
released from the seed cotton by the impact action of the cylinders.
Next, a stick machine removes any large sticks or hulls (the dried
bolls that form a shell around cotton as it grows) with revolving
channel saws. These saws grab the seed cotton and whip it over metal
bars to sling off its trash. If the seed cotton requires additional
drying and cleaning, gins will often run it through another drier
and another cylinder cleaner and stick machine.
Mechanical harvesters have made seed cotton drying and cleaning
necessary. Although mechanical harvesting is much faster than hand
harvesting, but mechanical harvesters also pick more trash with the
cotton, which usually contains a high amount of moisture. Trash, as
well as moisture, can adversely affect the quality of the fiber and
lead to costly operating and processing expenses at the gin and at
the textile mill. To prevent fiber damage and to facilitate ginning,
gins try to balance the moisture content in the seed cotton during
drying, so that it is neither too wet nor too dry. To add moisture
to it with a special humidifier that blows warm, humid air through
the gin's conveyor pipes.
Ginning the Seed Cotton
The seed cotton is now ready for ginning. Pima cotton is conveyed
to the roller gin, while upland cottons are conveyed to the saw gin
for separation of seed and fiber. After being ginned, the cotton
fiber is often referred to as lint.
Lint Cleaning
Lint cleaners remove the small trash from the ginned lint left
behind by the cylinder cleaner and stick machines. Saw-lint cleaners
grab the lint with a cylinder saw and whip it over metal bars to
dislodge its trash. Lint cleaning of roller ginned cotton usually
involves a combination of three machines: a cylinder cleaner, an
impact cleaner which uses cylinders to agitate and release the trash
from the lint, and an air-jet cleaner which removes the trash from
the lint using high velocity air.
Packaging the Lint
In the final stage, a bale press compresses the ginned lint into
bales that weigh between 160 to 165 Kg. The bales are then wrapped
with a protective cover, ready for delivery to the warehouse where
they are sold to various textile mills.
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