The shipping and handling of grain from farm to market was once a very awkward, inefficient process. Grain had to be moved about in sacks, and for longer journeys, it had to be transferred into difficult-to-handle barrels to protect it from the elements. The development of the grain elevator and the loading and unloading methods associated with it streamlined the grain production industry. American Oliver Evans patented a fully automated grain mill in 1785 that used an elevator consisting of an endless chain of buckets. This system was used to move the grain both at the storage elevator and at the mill. Mill operators did not accept Evans's elevator until after 1843 when another American, Joseph Dart, added steam power to it. Since the grain was delivered to large storage bins classified by type and quality, the grain inspectors no longer had to spend time examining every barrel.
In 1848 the first storage elevator was built in Chicago. Soon, other elevators were located at major transfer centers in the Great Lakes area and along rivers and rail lines. With the increased efficiency of grain transfer and transport, farmers could locate further from centers of population. Globally, more farming was done in regions, or belts, especially suited to,grain production, such as the Great Plains, Argentina, and the Ukraine. Today, there are four types of grain elevators, but the bucket elevator remains the most common type. It is capable of lifting grain to heights of three hundred feet at rates of two thousand tons per hour. The buckets move by either chain or conveyor belt. Similar to the bucket type is the continuous chain elevator. Paddles mounted on a chain move the grain forward inside a long steel tube either horizontally or vertically.
The pneumatic elevator literally vacuums grain from the holds of ships to dockside facilities. By using a flexible intake hose, changes in water level or the ship's own level as its load weight changes can be accommodated without adjusting the equipment. The system also loads vessels with a blower positioned above the open hatch. Another type is the Archimedean screw, or auger, elevator. Named for the Greek mathematician who designed it, the large rotating screw mechanism pushes the grain through a shaft horizontally or at angles up to eighty degrees. It is used in farm storage facilities, often as part of a larger pneumatic system. The grain and grain dust inside an elevator are highly combustible, resulting in constant danger of explosions and fire. Newer, concrete grain elevators, somewhat lessen fire risk.
Care also must be taken to prevent spoilage and reduce invasion from pests. A forced-air treatment was developed in the 1950s in the United States to keep stored grain aerated, reducing moisture accumulation and the need to fumigate for pests. Elevators similar to those used for grain are also used extensively in the limestone industry.
With the growth of agribusinesses, farmers have begun to find alternatives to the customary grain elevator. Mobile elevators lessen the need to transfer grain to a stationary elevator, and semitrailer trucks that move the product directly to railroads or processing plants offer greater safety, speed, and allow the farmer to choose the time and place for delivery.
This is the complete article, containing 532 words
(approx. 2 pages at 300 words per page).
