Barbara Heck, age 11, of Springfield, I11., for her question:
HOW MUCH DOES A GRAIN ELEVATOR HOLD?
A grain elevator is a tall building that is equipped with machinery for loading, unloading, cleaning, mixing and storing grain. There are two kinds of grain elevators: country elevators and terminal elevators.
Country elevators hold from 25,000 to 100,000 bushels of grain while nearly all terminal elevators hold over 1 million bushels of grain.
Country elevators are found in nearly every town in grain producing areas. These smaller elevators receive grain from farmers and generally store it for only short periods of time.
Grain is cleaned and conditioned in country elevators and then graded before it is shipped to the large markets in railroad cars. The grain elevators may be owned by independent businessmen, by farm cooperatives or by elevator companies.
Terminal elevators stand at large grain markets and shipping centers such as Chicago, Minneapolis, Duluth and Kansas City, Mo. In these elevators, grain is stored for the use of millers or to await shipment.
While nearly all terminal elevators hold over 1 million bushels of grain, one elevator in Wichita, Kan., can hold 43 million bushels.
Grain elevators were once made of wood. Today, country elevators are often made of concrete or steel and terminal elevators of concrete.
Most elevators are more than 100 feet high. Weighing and cleaning occur near the top, above the storage bins. This area is called the cupola or headhouse.
Railroad cars are unloaded at grain elevators by shoveling, or by means of devices that tip a boxcar so that the grain runs out of the doors.
Elevators for loading and unloading ships have marine legs on the dock side. To unload a vessel, the hatches are first removed and the legs are lowered into the holds.
Electrically operated buckets in the marine legs quickly raise the grain to the top of the cupola. From there, the grain goes through a scale hopper that weighs it, and then through a cleaner to the storage bins.
Large terminal elevators can unload about 10,000 bushels of grain per leg each hour.
A huge shipping port elevator can load the largest grain carrying ship in one day.
One huge grain elevator, located near Hutchinson, Kan., can store 17 million bushels of wheat. It is one half mile long and has 1,000 storage bins.
Wheat is the world's most important grain crop. Wheat covers more of the earth's surface than any other food crop. The world's farmers grow about 12 billion bushels of wheat each year. One bushel equals 60 pounds. This amount of wheat would fill a freight train stretching about twice around the world.