The Allround Shake grader is designed to grade potatoes according to their square size. The potatoes are fed to the top of the machine on to the top sieve. The sieves in the machine shake in sequential frequencies, which causes the potatoes to move along on the sieves.
The mesh of the sieves of the upper sieve deck is the largest, every sieve deck below is smaller. When the mesh is large enough, the potato will fall through the mesh, and ends on the mesh through which it cannot fall. At this grade, the potato will come out at the end.
In some cases it occurs that the potato gets stuck in the machine. To solve this, the Allround Shake grader has a system called a “screen cleaner“, which pushes the potatoes out of the sieve in case it gets stuck.
The movements of the sieves is caused by the motor on the front side of the machine. This motor drives a crankshaft. The crankshaft causes the shaking of the sieves. The motor of the machine has a computer controlled frequency inverter, which causes the sieves to shake in several sequential frequencies.