GRAIN ELEVATOR. A structure for the handling, storage, or cleaning of 'grain during, or preparatory to, its trans-shipment from rail way cars to vessels, and vice versa. In exterior appearance the modern grain elevator is a win dowless rectangular structure, surmounted by a cupola-like superstructure. The main body of the building, called the 'house,' is mostly occu pied with bins for the storage of grain, while the surmounting structure, which is generally three stories high and is called a cupola, contains the operating machinery and working rooms. Gen erally the topmost story of the cupola contains the leg-driving machinery and turnhead spouts, the middle story the garners, and the lowest story the weighing hoppers and cleaning ma chinery. Below the cupola and main roof, and extending over the entire width and length of the house, is the distributing or spout floor. Here are the conveyors, for transporting lengthwise to the building, and the distributing spouts, for transferring by gravity the grain from the scale hopper to the bins. By means of legs reaching from the bottom of pits sunk below the founda tions of the bins to the topmost story of the cupola, and continuing bucket conveyors, the grain is elevated to the turnhead points and dis charged into the garners. From these it passes to the lower floor, where it is weighed, cleaned if desired, and finally spouted to its proper bin. This description applies in general to all ele vators, but the construction and arrangement of details differ for different classes of elevators. The mode of operation of a grain elevator, de scribed without technicalities, is somewhat as follows: A string of cars is placed so that each car is opposite one of a number of elevator legs located about a car-length apart. The track may enter the building underneath the bins, or may pass along one or both sides of the building. Two shovelers enter each car, and handle each a shovel operated by a rope from a power-shovel shaft in the elevator. These shovels discharge into the hopper or pits into which the feet of the elevator legs descend. From these the bucket conveyors running inside the legs hoist the grain to the top most story of the cupola, where it is discharged, in turning over a head pulley, into the hopper of the turnhead spouts, thence into the garners, and thence into the weighing hoppers. From the scale hoppers the grain is spouted: (1) Upon belt conveyors running longitudinally across the building and discharging over movable trippers into storage bins (storage elevators) ; (2) into car spouts, for reloading or transferring (rail way transfer elevators) ; (3) directly into stor age bins, which may be (a) shipping bins with dock spouts, to be loaded into vessels; (b) into car spouts (terminal elevators) ; or (c) into garners above cleaning machinery (cleaning ele vators). All of these classes of elevators are designed for taking grain from railway cars and transferring it to vessels or to other railway cars.
Marine elevators, for transferring grain from vessels to railway cars, are provided on the dock side with elevator legs outside of the house, which are mounted on wheels permitting move ment along the side of the house and allowing the legs to be set opposite the vessel's hatches.
These marine legs convey the grain to the turn head spouts, whence it passes to the garners, scales, cleaning machinery, if desired, or to the car-loading spouts. There is another class of elevators, comprising small elevators at railway stations for receiving grain from farmers' wagons and transferring it to cars. Floating elevators are structures similar to land elevators, which are mounted on floats or barges, which permit the transportation of the structure from one point of a harbor to another.
In America, the most common construction for elevators is timber, constructed sometimes with thin brick outside protecting walls for the house, and corrugated iron covering for the roof and cupola walls. The purpose of this incombustible outside covering was to decrease the danger from fire, and for this purpose it was evidently su perior to unprotected timber construction. This outside protection, however, was of little prac tical value once fire had gained access to the timber interior, and even with its use insurance rates were very high. As a result, there has been a strong tendency among elevator men in recent years to build fireproof elevators. This con struction has usually taken the form of steel bins inclosed by a house with brick walls, and a cupola built entirely of steel framing, covered with terra-cotta or iron, and having tile or sheet steel floors. Sometimes the bins are made of concrete, with an imbedded steel skeleton; ele vators of this construction have been used more extensively in Europe than in America.
Another type of fireproof elevator construction considerably practiced in America consists in building the storage bins of steel separated from the fireproof buildings containing the operating machinery. A system of pneumatic conveyors for handling the grain between the bins and the operating house, and for loading and unloading it, is an essential part of this type of elevator. As an indication of the character and extent of the elevator business, reference may be made to the records of grain handled by the public ele vators of Chicago, III. In Illinois the public elevators, like a railway, are compelled to handle all grain submitted to them, for storage and trans shipment up to the limit of their capacity, and without discrimination, so long as the grain is not diseased or otherwise injured. For this ser vice they are permitted to charge any rate up to a .maximum of I14 cents per bushel for the first ten days or portion thereof, and of cent per bushel for each ten days afterwards. The total storage capacity of the public elevators of Chicago in 1900 was 31,900,000 bushels of grain at one time, and the capacity of individual ele vators ranged from 700,000 bushels to 4,000,000 bushels. These elevators, working together, were capable of unloading 2245 carloads of grain every ten hours. The total amount of grain received into stores by these elevators in 1900 was 72, 961,273 bushels.