Cleaner and Grader

a machine or the main element of an integrated grain-cleaning machine, used to separate the seeds of a main crop from various types of unwanted matter, such as seeds of other crops and weeds, and to sort the cleaned seeds according to length. The working element of a cleaner and grader is a cylinder or disk indented with small pockets. Cylinder machines are more commonly used in agriculture; disk types are used in mills and grain-receiving stations.

The USSR manufactures the ZAV-10.90000 and BT-5 cylinder-type units. The former is driven by a 2.2-kilowatt electric motor and has an output of 7.5 tons per hr; the latter has a 1.5-kilowatt electric motor and an output of 5 tons per hr. Both machines are used only in grain-cleaning production lines.

The cleaning and grading cylinders operate in the following manner. A grain mixture containing short and long seeds is fed to the rotating cylinder. The pockets on the cylinder trap those seeds shorter than the diameter of the pockets, and the longer seeds are scattered over the surface of the cylinder. As the cylinder turns, the pile of seeds is lifted up along the side of the cylinder. At a certain point, the seeds fall from the pockets under their own weight and are deposited on a chute inside the cylinder. A screw conveyor for ejecting the seeds from the machine is located at the bottom of the cylinder. The long seeds are lifted to a certain height along the cylinder sides by means of friction. They then fall, move across the surface of the cylinder along the cylinder axis, and are ejected from the opposite side.

Cylinder machines are manufactured in both single and double format. In the former, all the cylinder pockets are of the same size. Double-format machines have two cylinders, each with pockets of a different size; these remove the long particles of unwanted material first and then the shorter particles, or vice versa.

The disks in a disk cleaner and grader also have pockets. As the disks turn, seeds smaller than the size of the pockets are trapped and ejected. Long seeds that do not fit in the pockets are moved along the machine housing by means of blades attached to the spokes of the disks and are then ejected.