Grain-cleaning machine

A GRAIN-CLEANING MACHINE, comprising

• a housing (12) having an inlet opening (13),
• an arrangement of sieves disposed internally of the housing (12),
• a vibration system configured to oscillate the arrangement of sieves,
• characterized by
• the arrangement of sieves comprises
• at least two main sieve levels (14a, 14b, 14c) positioned overlapping each other and having an inclination to the horizontal from a high side (L1) to a low side (L2), each main sieve level (14a, 14b, 14c) comprising a respective fine sieve (141) followed by a respective grain sieve (142), wherein a respective fine-carrying channel (143) is arranged below each fine sieve (141) in communication with at least one outlet of residues smaller than grains (18) and below each grain sieve (142) is disposed a respective grain carrying channel (144) in communication with at least one grain outlet (19),
• at least one lower sieve level (16) comprising a respective lower grain sieve (162), wherein a lower grain-carrying channel (164) is arranged below the lower grain sieve (162) in communication with at least one grain outlet (19),
• the at least one lower sieve level (16) being positioned below the main sieve levels (14a, 14b, 14c), and inclined to the horizontal from a high side (L3) to a low side (L4), wherein the low side (L2) of each main sieve level (14a, 14b, 14c) is in communication with the high side (L3) of the at least one lower sieve level (16) through a vertical passage (17) and the low side (L4) of the lower sieve level (16) is in communication with at least one outlet of residues larger than grains (20),
• where each fine sieve (141) has a mesh configured to allow traversal of residues smaller than grains (R<) and each grain sieve (142, 162) has a mesh configured to allow traversal of grains (G, Ge).