|source: amity technology|
Sugar beets are grown under a wide variety of soil and climatic conditions. These factors cause the roots and tops to develop different areas, making it difficult to adapt machines to the varied types of growth, soil, and weed condition and to meet the desires of the growers.
Patents were granted on mechanical sugar-beet harvesters as early as 1898. Machines were used to some extent in the 1930s, but it took the scarcity of labor during the Second World War to bring farmers to accept and use the machines available. Large-scale use of beet harvesters began in 1943, and by 1953 probably 80 percent of the beets grown were mechanically harvested. In 1962 almost all the sugar beet crop was mechanically harvested.
Beet harvesters may be either tractor-mounted, trailed behind the tractor, or self-propelled. The mechanism in all three types is power-takeoff-driven. One, two, and six-row sizes are available. The harvesters are operated from 2 ¼ to 5 mi/h and can harvest from 25 to 30 acres per day.
Topping the beets
Beet leaves can be removed by letting herds of sheep graze them off, by the beating them with rotary beaters, or by topping devices. Most beets are topped before they are lifted from the ground. It consist of a power-driven, notched-edged disk set flat to scoop off the beets slightly below or above the lowest leaf scar, depending on the size of the beets. The position of the topping disk is gaged by a finder, which may be a sliding shoe, a power-driven wheel roller, or a belt. The pressure spring should not exert a force of 60 lb. The tops are thrown to one side by a power-driven top flinger. Beets can be topped before the digger is operated by tractor-mounted scalping knives.
Lifting the beets
The lifting unit is mounted just back of the topper. The soil can be loosened around the beets by two large, notched rolling colters set a few inches apart and at an angle.
There are four types of beet lifters. The oldest and simplest consists of two helical-shaped blades that straddle the row. The second type consists of two spade or solid-rim-type wheels tilted or angled so the rim closes under and lifts the beets from the soil. The third method of lifting beets consists of a large spiked wheel some 76.2 cm in diameter. The spikes are forced into the roots as the wheel rolls over them. As the wheel turns, the roots are lifted from the soil. The fourth device for removing beet roots from the soil consists of a pair of inclined spring-loaded belts that grasp the tops and lift them as the belts move up the incline. The soil is loosened around the roots by a pair of digger blades.
The cleaning mechanism
The soil that is lifted with the beet roots is removed as the beets pass over several rows of rotating and overlapping star-shaped kicker wheels by some types of beet harvesters. The soil drops out between the star wheels, but the beets are flipped from one row of wheels to another until they are delivered to the elevator.
Some machines are provided with a sorting belt so that rocks and large, hard clods of dirt can be picked out manually.
Some beet harvesters have elevators that dump the beets directly into a truck box, while others deposit the beets in a tank on the machine. When the tank is filled, it is unloaded by a chain flight elevator. This type of beet harvesters can be termed a beet combine.