Cotton gin
Overview
 
A cotton gin (short for cotton engine) is a machine that quickly and easily separates cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 fibers from their seeds, a job formerly performed painstakingly by hand. The fibers are processed into cotton goods, and the seeds may be used to grow more cotton or to produce cottonseed oil
Cottonseed oil
Cottonseed oil is a cooking oil extracted from the seeds of cotton plant of various species, mainly Gossypium hirsutum and Gossypium herbaceum...

; if they are badly damaged, they are disposed of.

The first modern mechanical cotton gin was created by American inventor Eli Whitney
Eli Whitney
Eli Whitney was an American inventor best known for inventing the cotton gin. This was one of the key inventions of the Industrial Revolution and shaped the economy of the Antebellum South...

 in 1793 and patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

ed in 1794.
Encyclopedia
A cotton gin (short for cotton engine) is a machine that quickly and easily separates cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 fibers from their seeds, a job formerly performed painstakingly by hand. The fibers are processed into cotton goods, and the seeds may be used to grow more cotton or to produce cottonseed oil
Cottonseed oil
Cottonseed oil is a cooking oil extracted from the seeds of cotton plant of various species, mainly Gossypium hirsutum and Gossypium herbaceum...

; if they are badly damaged, they are disposed of.

The first modern mechanical cotton gin was created by American inventor Eli Whitney
Eli Whitney
Eli Whitney was an American inventor best known for inventing the cotton gin. This was one of the key inventions of the Industrial Revolution and shaped the economy of the Antebellum South...

 in 1793 and patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

ed in 1794. It used a combination of a wire screen and small wire hooks to pull the cotton through, while brushes continuously removed the loose cotton lint to prevent jams. Larger, more complex, automated cotton gins remain a crucial part of the cotton industry today.

Early cotton gins

The earliest versions of the cotton gin consisted of a single roller made of iron or wood and a flat piece of stone or wood. Evidence for this type of gin has been found in Africa, Asia, and North America. The first documentation of the cotton gin by contemporary scholars is found in the fifth century AD, in the form of fifth-century Buddhist paintings depicting a single-roller gin in the Ajanta Caves in western India. These early gins were difficult to use and required a great deal of skill. A narrow single roller was necessary to expel the seeds from the cotton without crushing the seeds. The design was similar to that of a metate
Metate
A metate is a mortar, a ground stone tool used for processing grain and seeds. In traditional Mesoamerican culture, metates were typically used by women who would grind calcified maize and other organic materials during food preparation...

, which was used to grind grain. The early history of the cotton gin is ambiguous, because archeologists likely mistook the cotton gin's parts for other tools.

Between the twelfth and fourteenth centuries, dual-roller gins appeared in India and China. The Indian version of the dual-roller gin was prevalent throughout the Mediterranean cotton trade by the sixteenth century. This mechanical device was, in some areas, driven by water power.

Eli Whitney's patent

The modern mechanical cotton gin was invented in 1793 by Eli Whitney
Eli Whitney
Eli Whitney was an American inventor best known for inventing the cotton gin. This was one of the key inventions of the Industrial Revolution and shaped the economy of the Antebellum South...

 (1765–1825). Whitney applied for a patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

 on October 28, 1793; the patent was granted on March 14, 1794, but was not validated until 1807. There is slight controversy over whether the idea of the modern cotton gin and its constituent elements are correctly attributed to Eli Whitney. The popular image of Whitney inventing the cotton gin is attributed to an article on the subject written in the early 1870s and later reprinted in 1910 in The Library of Southern Literature. In this article, the author claimed that Catherine Littlefield Greene
Catherine Littlefield Greene
Catharine Littlefield "Caty" Greene was the wife of American Revolutionary War general Nathanael Greene, a mother of five, and noted for being a supporter of inventor Eli Whitney.-Early life:...

 suggested to Whitney the use of a brush-like component instrumental in separating out the seeds and cotton. To date, there has been no independent verification of Greene's role in the invention of the gin.

Many contemporary inventors attempted to develop a design that would process short staple cotton, and Hodgen Holmes, Robert Watkins, William Longstreet
William Longstreet
William Longstreet was an inventor. He made a steamboat and improved the cotton gin.As a boy, he moved to Augusta, Georgia...

, and John Murray had all been issued patents for improvements to the cotton gin by 1796. However, the evidence indicates that Whitney did invent the saw gin, for which he is famous. Although he spent many years in court attempting to enforce his patent against planters who made unauthorized copies, a change in patent law ultimately made his claim legally enforceable – too late for him to make much money off of the device in the single year remaining before the patent expired.

Whitney's design

Whitney's cotton gin model was capable of cleaning 50 pounds (22.7 kg) of lint per day. The model consisted of a wooden cylinder surrounded by rows of slender spikes, which pulled the lint through the bars of a comb-like grid. The grids were closely spaced, preventing the seeds from passing through. Loose cotton was brushed off, preventing the mechanism from jamming.

Effects of the cotton gin

Prior to the introduction of the mechanical cotton gin, cotton had required considerable labor to clean and separate the fibers from the seeds. With Eli Whitney’s introduction of “teeth” in his cotton gin to comb out the cotton and separate the seeds, cotton became a tremendously profitable business, creating many fortunes in the Antebellum South
History of the United States (1789–1849)
With the election of George Washington as the first president in 1789, the new government acted quickly to rebuild the nation's financial structure. Enacting the program of Treasury Secretary Alexander Hamilton, the government assumed the Revolutionary war debts of the state and the national...

. New Orleans and Galveston were shipping points that derived substantial economic benefit from cotton raised throughout the South. Additionally, the greatly expanded supply of cotton created strong demand for textile machinery and improved machine designs that replaced wooden parts with metal. This led to the invention of many machine tool
Machine tool
A machine tool is a machine, typically powered other than by human muscle , used to make manufactured parts in various ways that include cutting or certain other kinds of deformation...

s in the early 19th century.

The invention of the cotton gin caused massive growth in the production of cotton in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, concentrated mostly in the South. Cotton production expanded from 750,000 bales in 1830 to 2.85 million bales in 1850. As a result, the South became even more dependent on plantations and slavery
Slavery
Slavery is a system under which people are treated as property to be bought and sold, and are forced to work. Slaves can be held against their will from the time of their capture, purchase or birth, and deprived of the right to leave, to refuse to work, or to demand compensation...

, with plantation agriculture becoming the largest sector of the Southern economy. The number of slaves rose in concert with the increase in cotton production, increasing from around 700,000 in 1790 to around 3.2 million in 1850. By 1860, the southern states were providing two-thirds of the world’s supply of cotton, and up to eighty percent of the crucial British market.

According to the Eli Whitney Museum website:
Whitney (who died in 1825) could not have foreseen the ways in which his invention would change society for the worse. The most significant of these was the growth of slavery. While it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton. In fact, the opposite occurred. Cotton growing became so profitable for the planters that it greatly increased their demand for both land and slave labor. In 1790 there were six slave states; in 1860 there were 15. From 1790 until Congress banned the importation of slaves from Africa in 1808, Southerners imported 80,000 Africans. By 1860 approximately one in three Southerners was a slave.


Due to its inadvertent effect on American slavery, the invention of the cotton gin is frequently cited as one of the ultimate causes of the American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

.

Modern cotton gins

In modern cotton production, cotton arrives at cotton gins either in trailers or in compressed "modules
Cotton module builder
The cotton module builder is a machine used in the harvest and processing of cotton. The module builder has helped to solve a logistical bottleneck by allowing cotton to be harvested quickly and compressed into large modules which are then tarped and temporarily stored at the edge of the field...

", which weigh up to ten metric tons each. The need for trailers to haul the product to the gin has been drastically reduced since the introduction of the module. Cotton arriving in trailers is sucked into the gin via a pipe, approximately 16 inches in diameter, that is swung over the cotton. This pipe is usually manually operated, but is increasingly automated in modern cotton plants. If the cotton is shipped in modules, the module feeder breaks the modules apart using spiked rollers and extracts foreign material from the cotton. The module feeder's loose cotton is then sucked into the same starting point as the trailer cotton.

The cotton then enters a dryer, which removes excess moisture. The cylinder cleaner uses six or seven rotating spiked cylinders to break up large clumps of cotton. Finer foreign material, such as dirt and leaves, passes through rods or screens for removal. The stick machine uses centrifugal force
Centrifugal force
Centrifugal force can generally be any force directed outward relative to some origin. More particularly, in classical mechanics, the centrifugal force is an outward force which arises when describing the motion of objects in a rotating reference frame...

 to remove larger foreign matter, such as sticks and burrs, while the cotton is held by rapidly rotating saw cylinders.

The gin stand uses the teeth of rotating saws to pull the cotton through a series of "ginning ribs", which pull the fibers from the seeds which are too small to pass through the ribs. The cleaned seed is then removed from the gin via an auger
Auger
An auger is a drilling device, or drill bit, that usually includes a rotating helical screw blade called a "flighting" to act as a screw conveyor to remove the drilled out material...

 system. The seed is reused for planting or is sent to an oil mill to be further processed into usable items. The lint cleaners again use saws and grid bars, this time to separate immature seeds and any remaining foreign matter from the fibers. The bale press then compresses the cotton into bales for storage and shipping. Modern gins can process up to 15 tonnes (33,069.3 lb) of cotton an hour.>

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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