Secondary cutoff configuration for a cross-flow fan
A harvester cleaning fan system having a cross flow fan rotor, a fan inlet, a rotor shroud, a fan outlet and a cutoff wall assembly. The fan inlet extends in the fan rotation direction around a first portion of the cylindrical rotation volume. The rotor shroud is adjacent the fan inlet and extends in the rotation direction to enclose a second portion of the cylindrical rotation volume. The fan outlet is adjacent the rotor shroud. The cutoff wall assembly extends in the rotation direction by a cutoff wall distance to enclose a third portion of the cylindrical rotation volume. The cutoff wall assembly has a first cutoff wall and a second cutoff wall. The cutoff wall distance is about 40 mm to about 90 mm, and the fan has a rotation diameter of about 400 mm to about 500 mm.
1 . A harvester cleaning fan system comprising:
a cross flow fan rotor rotatable about a fan axis in a rotation direction, the cross flow fan rotor having a plurality of vanes, each of the plurality of vanes extending a radial vane distance, in a radial direction away from the fan axis, from a respective proximal vane edge to a respective distal vane edge, the distal vane edges defining a cylindrical rotation volume having a rotation diameter;
a fan inlet extending in the rotation direction around a first portion of the cylindrical rotation volume;
a rotor shroud adjacent to the fan inlet and extending in the rotation direction to enclose a second portion of the cylindrical rotation volume;
a fan outlet adjacent to the rotor shroud that directs airflow away from the fan rotor; and
a cutoff wall assembly spaced from the fan axis and extending in the rotation direction by a cutoff wall distance to enclose a third portion of the cylindrical rotation volume, the cutoff wall assembly comprising a first cutoff wall located adjacent to the cylindrical rotation volume at the fan outlet, and a second cutoff wall located adjacent to the cylindrical rotation volume at the fan inlet, wherein the second cutoff wall comprises plurality of openings therethrough;
wherein the cutoff wall distance is about 40 mm to about 90 mm, and the fan has a rotation diameter of about 400 mm to about 500 mm.
2 . The harvester cleaning fan system of claim 1 , wherein the second cutoff wall is spaced from the cylindrical rotation volume by about 10 mm to about 15 mm.
3 . The harvester cleaning fan system of claim 1 , wherein the first portion of the cylindrical rotation volume extends about 90° to about 100° about the rotation axis, and the third portion of the cylindrical rotation volume extends about 15° to about 25° about the rotation axis.
4 . The harvester cleaning fan system of claim 1 , wherein the radial vane distance is about 60 mm to about 75 mm.
5 . The harvester cleaning fan system of claim 1 , wherein the first portion of the cylindrical rotation volume extends about 90° to about 100° about the rotation axis, the third portion of the cylindrical rotation volume extends about 15° to about 25° about the rotation axis, and the radial vane distance is about 60 mm to about 75 mm.
6 . The harvester cleaning fan system of claim 1 , wherein the fan outlet is in fluid communication with an outlet duct having minimum width (W) as measured in a plane perpendicular to the rotation axis of about 160 mm to about 200 mm.
7 . The harvester cleaning fan system of claim 1 , wherein the fan outlet is in fluid communication with a divided outlet duct.
8 . The harvester cleaning fan system of claim 1 , wherein the cutoff wall assembly further comprises a closure wall extending from the first cutoff wall adjacent to the cylindrical rotation volume to the second cutoff wall adjacent to the cylindrical rotation volume.
9 . The harvester cleaning fan system of claim 1 , wherein a majority of the second cutoff wall comprises a plurality of openings therethrough.
10 . The harvester cleaning fan system of claim 9 , wherein substantially all of the second cutoff wall comprises a plurality of openings therethrough.
11 . The harvester cleaning fan system of claim 1 , wherein the second cutoff wall comprises at least about 30% open area.
12 . An agricultural vehicle comprising:
a chassis enabling movement along a surface;
one or more sieves that separate grain from material other than grain; and a fan system comprising:
a cross flow fan rotor that rotates about a fan axis in a rotation direction, the cross flow fan rotor having a plurality of vanes, each of the plurality of vanes extending a radial vane distance, in a radial direction away from the fan axis, from a respective proximal vane edge to a respective distal vane edge, the distal vane edges defining a cylindrical rotation volume having a rotation diameter,
a fan inlet extending in the rotation direction around a first portion of the cylindrical rotation volume, a rotor shroud adjacent to the fan inlet and extending in the rotation direction to enclose a second portion of the cylindrical rotation volume, a fan outlet adjacent to the rotor shroud that directs airflow away from the fan rotor, and
a cutoff wall assembly spaced from the fan axis and extending in the rotation direction by a cutoff wall distance to enclose a third portion of the cylindrical rotation volume, the cutoff wall assembly comprising a first cutoff wall located adjacent to the cylindrical rotation volume at the fan outlet, and a second cutoff wall located adjacent to the cylindrical rotation volume at the fan inlet, wherein the second and cutoff wall comprises a plurality of openings therethrough,
wherein the cutoff wall distance is about 40 mm to about 90 mm, and the fan has a rotation diameter of about 400 mm to about 500 mm.
13 . The agricultural vehicle of claim 12 , wherein the second cutoff wall is spaced from the cylindrical rotation volume by about 10 mm to about 15 mm.
14 . The agricultural vehicle of claim 12 , wherein the first portion of the cylindrical rotation volume extends about 90° to about 100° about the rotation axis, and the third portion of the cylindrical rotation volume extends about 15° to about 25° about the rotation axis.
15 . The agricultural vehicle of claim 12 , wherein the radial vane distance is about 60 mm to about 75 mm.
16 . The agricultural vehicle of claim 12 , wherein the first portion of the cylindrical rotation volume extends about 90° to about 100° about the rotation axis, the third portion of the cylindrical rotation volume extends about 15° to about 25° about the rotation axis, and the radial vane distance is about 60 mm to about 75 mm.
17 . The agricultural vehicle of claim 12 , wherein the fan outlet is in fluid communication with an outlet duct having minimum width (W) as measured in a plane perpendicular to the rotation axis of about 160 mm to about 200 mm.
18 . The agricultural vehicle of claim 12 , wherein the fan outlet is in fluid communication with a divided outlet duct.
19 . The agricultural vehicle of claim 12 , wherein the cutoff wall assembly further comprises a closure wall extending from the first cutoff wall adjacent to the cylindrical rotation volume to the second cutoff wall adjacent to the cylindrical rotation volume.
20 . The agricultural vehicle of claim 12 , wherein a majority of the second cutoff wall comprises a plurality of openings therethrough.
21 . The agricultural vehicle of claim 20 , wherein substantially all of the second cutoff wall comprises a plurality of openings therethrough.
22 . The agricultural vehicle of claim 20 , wherein the second cutoff wall comprises at least about 30% open area.