1-ginning.pptx document textile engineering

ginning

1. Yarn manufacturing one Ginning

2. 1. TERMINOLOGIES OF GINNING L int:- lints are long cotton fibres separated from seed cotton. L inter:- these are very short cotton fibres that remained with seed after ginning . G inning out turn(g.o.t):- it is the ratio of the lint by weight to the weight of seed cotton. G in 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 G inning 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. I t has capacity of 13-15 bales per hour

7. WORKING PRINCIPLE Entrance in gin stand. S aws 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 I t 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 C otton 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 S low process Less fibre damage For long staple fibres C apacity 600-750 pounds of lint per hour(1lb= 0.453kg), or 1.89bale SAW GINNING F ast process More fibre damage For short staple fibres C apacity 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 H eated air OPTIMUM CONDITIONS Temperature M oisture Duration of drying PURPOSES OF DRYING S mooth 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 B y 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 .

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