ginning

1. Yarn manufacturing one
Ginning

2. 1. TERMINOLOGIES OF GINNING
• Lint:- lints are long cotton fibres separated from seed cotton.
• Linter:- these are very short cotton fibres that remained with seed
after ginning.
• Ginning out turn(g.o.t):- it is the ratio of the lint by weight to the
weight of seed cotton.
• Gin cut cotton:- cotton fibres which have been cut, broken,
twisted by the saws of the gin when the cotton is too damp.

3. 2. Overview of the Cotton Ginning
 Ginning is the process to separate lint from seed to create
two marketable products, fiber and seed.
Objectives of ginning
 Conditioning
 Lint separation
 Cleaning

4. 3. Types of ginning
3.1. Saw ginning
3.2. Roller ginning

5. 3.1. Saw ginning
In saw gins, the cotton lint is removed from the seed by pulling it
with saw teeth through metallic ribs.
 Each saw passes between two stationary steel ribs spaced so as to
allow the lint to pass through while preventing the cotton seed
from doing so.
The principal parts of a saw gin are saws, ribs and a brush or a blast
of air for cleaning the lint from the saws.

6. …cont’d
 Used for medium and short staple varieties.
The number of gin stands installed and the number of saws per
stand determine the capacity of a ginnery,
which is also limited by the capacity of the baling press and of the
feeding and cleaning machinery.
It has capacity of 13-15 bales per hour

7. WORKING PRINCIPLE
Entrance in gin stand.
Saws grasps the cotton and draw it
through widely spaced ribs.
 Spaces are sufficient for fiber passing
while seeds remain there.

8. Picture of gin stand

9. 3.2. Roller Ginning
 Roller ginning is the most primitive
way of removing lint from seeds.
 Separation of lint by means of
roller and knife.

10. …cont’d
• It is used for long and extra long fibres.
• Fibers are gripped between rollers, or a roller and a knife and
stretched to be separated from seeds.
• The space through which fibers are stretched is so narrow that it
does not permit seeds passing through with lint.
• The process is comparatively slow but considered to be gentle.

11. WORKING PRINCIPLE
Cotton slides down the feeder
 Enters the gin b/w ginning roller & rotary knife
 Revolving roller held against knife pulls the lint

12. 3.3 COMPARISON
ROLLER GINNING
 Slow process
 Less fibre damage
 For long staple fibres
 Capacity 600-750 pounds of lint per
hour(1lb= 0.453kg), or 1.89bale
SAW GINNING
 Fast process
 More fibre damage
 For short staple fibres
 Capacity 13-15 bales of lint per hour(1
bale= 180kg)

13. 4. PROCESS FLOW DIAGRAM

14. 4.1 Module feeder
Compacted cotton as it comes from the field begins processing in the module
feeder.
 The modules are transported to the stationary dispersing head on a series of
beds: each bed is the length of a module and is transported by flat wire-mesh
belts or of chains.
The stationary head feeder employs a dispersing head with spiked rollers for
breaking apart the module
Video camera and moisture sensors in the feeder relay information about color,
trash, and moisture to a computer.

15. 4.2 DRYER
Cotton may bypass the dryers completely or dryer temperatures may be adjusted higher or
lower, depending on instructions from the computer.
WORKING PRINCIPLE
Heated air
OPTIMUM CONDITIONS
Temperature
Moisture
 Duration of drying
PURPOSES OF DRYING
Smooth operation of process and to prevent fiber damage
Separation into single flocks
 Control moisture in seed cotton

16. 4.3 CYLINDER CLEANER
Cylinder cleaners —One or more stages may be needed, depending on
the intended market quality of the cotton
PURPOSE
To remove fine impurities( leaf, trash, dirt)
Opening of flocks
PRINCIPLE
The spiked cylinders scrub the cotton over a series of grid rods , agitate the
cotton, and allow fine foreign materials, such as leaves, trash, and dirt, to pass
through the openings for disposal.

17. 4.4 STICK MACHINE
PURPOSE
 Removal of larger foreign matter (sticks)
PRINCIPLE
 Stick machines use the centrifugal force created by saw cylinders rotating
at high speed (300-400 rpm) to "sling off“ or throw foreign material while
the fiber is held by the saw.

18. 4.5 EXTRACTER FEEDER
 The primary function of the extractor-feeder is to feed seed cotton to the gin stand
uniformly and at controllable rates.
 Extracting and cleaning is a secondary function.
 The feed rate of seed cotton is controlled by the speed of two star-shaped feed rollers
located at the top of the extractor feeder directly under the distributor hopper.
 The two star-shaped feed rollers 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.

19. 4.6 GIN STAND
OBJECTIVES OF GIN STAND
To separate the lint cotton from seed
To remove foreign matter
WORKING PRINCIPLE
By the action of set of rotating saws

20. Gin stand main parts and their function
S.no Part Name Function
1 Huller front Cotton enters the gin stand through a huller front
2 Saws The saws grasp the cotton and draw it through widely spaced ribs known as
huller ribs
3 Huller ribs The locks of cotton are drawn from the huller ribs into the bottom of the
roll box.
4 Roll box The actual ginning process--separation of lint and seed-takes place in the
roll box of the gin stand.
5 Brush/a blast of air For cleaning the lint from the saws.

21. 4.7 LINT CLEANER
It is very important for cotton to flow uniformly and be well dispersed,
particularly as it leaves the gin stand.
Cotton is conveyed from the gin stand through lint ducts to condensers
and formed into a batt.
The batt is removed from the condenser drum and fed into the saw-
type lint cleaner.
Inside the lint cleaner, cotton passes through the feed rollers and over
the feed plate, which applies the fibers to the lint cleaner saw.
The saw carries cotton under grid bars, which are aided by centrifugal
force and remove immature seeds and foreign matter.

22. 4.8 BALE PRESS
The cleaned cotton is compressed into bales, which must then be
covered to protect them from contamination during transportation
and storage.
In most gins cotton is packaged in a "double-box" press wherein the
lint is initially compacted in one press box by a mechanical or
hydraulic tramper;
Then the press box is rotated, and the lint is further compressed to
specific size by modified flat or gin universal density presses.

23. GIN HOUSEKEEPING
 Good housekeeping can be extremely important in keeping a gin safe.
 Housekeeping can also be an indication of the attention that is given to safety.
 Good housekeeping is the foundation for a safe, healthful and pleasant place to work.
 The general rule for good housekeeping is: ''A place for everything and everything in its
place".
 Keep materials and equipment out of a passageways or walk ways.
 Return tools and equipment to the proper storage place after use.
 Keep floors dry and avoid spilling liquids, especially oils. Clean up all spills immediately.

24. Thank you