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Design placed in the Public Domain
by
Allen Dong and Roger Edberg
I-Tech -
P.O. Box 413, Veneta OR 97487
A - Rectangular sheet metal
air duct, 24 inch long x 10 inch wide x 3-½ inch deep, available from
heating and ventilation supply houses.
B - Sheet metal tray, make
your own.
C - Sheave (V- belt pulley),
14-inch diameter, available from WW Grainger (3X943 or 3X942)
(1-800-323-0620).
D - Crank handle, make your
own.
E - V-belt.
F - Blower with 9-½ inch
diameter wheel (4C589) or larger, available form WW Grainger.
G - Sheet metal cover and
adapter to merger blower (F) with air duct (A).
H - Sheave, ½ inch bore, 1 ½
diameter and a pillow block, ½ inch diameter bore
I - 1 x 2 inch steel channel
or 2 x 4 inch wood upright support.
J - 1 x 2 inch steel channel
or 2 x 4 inch wood base for winnower.
Operation:
The winnower separates seeds
from chaff by blowing the less dense chaff away as seeds fall down a
column of air. Place the seed and chaff mixture on the tray (B). Turn the
crank handle (D) and move the seed mixture into the air duct (A). Manually
adjust the crank speed to provide enough airflow to lift the lighter chaff
up and out the top of the air duct, while allowing the denser seeds fall
through the bottom of the air duct.
Construction (brief
description):
The air duct (A) is
purchased from a hardware store. Cut a 2 x 9 inch slot across the air
duct, 6 inches from the end. This slot receives the tray (B), and allows
seed and chaff on the tray to be introduced into the air duct (A). The
tray (B) is made from a 16 x 24 inch, 20-gauge sheet metal. Fold 3 sides
up 3 inches and fold the fourth side down 1 inch to make a 10 x 20 inch
tray. Trim the fourth side ½ inch from both ends leaving a 9-inch lip that
inserts and hooks on to the 2 x 9 inch slot in the air duct (A).
Attach the upright supports
(I) to the blower (F) with the blower tilted up 22 ½ degrees, 6 inches off
the ground and the axle of the blower wheel is centered on the pillow
block/sheave (H). Make base (J). Attach supports (I) to base (J). If
supports (I) and base (J) are made from 2 x 4 wood, add diagonal braces
(not shown) to strengthen the join. No additional brace is needed if the
upright supports (I) and base (J) are 2 inch steel channels and are welded
together. A spacer is attached across the top of the two upright supports
(I), (not visible in diagram). The spacer provides bottom support for the
tray (B). The 14-inch sheave mounts on to the upright support using a
rigid pillow block or two self-aligning pillow blocks, one on each side of
the upright support.
Make a sheet metal cover and
adapter (G) to merge blower (F) with air duct (A) at 45-degree angle
between blower and air duct. A 45-degree air duct elbow can be used as
part of the adapter. The sheet metal cover leaves a 1-½ inch gap at the
bottom of the blower (F) for air to discharge into the air duct (A). Place
a ¼ inch mesh screen (not visible in diagram) across the 1-½ inch gap to
prevent debris from entering into the blower.
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