General Information
01-18 79032996 A Rev.
Threshing and Separating
Threshing and separating occur in a 229 cm (90 in)
cylinder and cage assembly mounted from left to right
between the front and rear axles. The standard cylinder is
an open design with eight equally spaced rows of cylinder
bars (4). An optional cylinder is a closed design with six
equally spaced rows of cylinder bars. The cylinder is
driven by a torque sensing variable speed belt drive and a
two speed gearbox (speed range of 200 rpm to 1096
rpm). The cylinder is mounted inside a perforated metal
cylindrical cage assembly. Material is fed into the cylinder
by a 99.1 cm (39 in) wide feed conveyor to the cylinder.
The first section of the cage reached by the crop is an
adjustable, open concave section where most of the
threshing action occurs. Helical bars on the inside of the
cage and the angled rasps on the cylinder bars then move
the material from right to left in a spiral route around the
cylinder. Grain is separated from the material by
centrifugal force. At the left-hand end of the cage, paddles
(5) on the cylinder direct the material to an impeller or
optional high speed fine cut chopper (6) which sends the
material to the straw spreader (7) at the rear of the
machine.
Cleaning
Material passing through the perforated cage assembly
falls into distribution augers (8) which provide even
distribution of material to the accelerator rolls (9) which
start the first stage of cleaning. The rolls have flutes that
overlap and turn in opposite directions to accelerate the
material through a band of high velocity air onto the shoe
grain pan. The air blast removes a large amount of
material from the grain, reducing the volume of material to
be cleaned by the shoe. Also, accelerating the material
reduces the effects of gravity when operating on slopes.
In the second stage of cleaning, the lower fan outlet sends
a controlled volume of air to the end shaker type shoe.
Here, an equal distribution of air across the complete
width and length of the shoe does the cleaning.
The fan (10) has curved blades and runs at a constant
speed. Air is taken in from directly in front of the fan and
across the fans complete width, for straight in straight out
air control...no corner turning. The ends of the fan are
closed and the inlet has a screen to prevent trash from
entering. Air flow is controlled from the platform, quickly
and easily, to keep more grain and get a cleaner sample.
In general, as wide an opening as possible on the chaffer
and as much air as possible without blowing grain out will
give the most shoe capacity. If grain is being blown out,
the grain can be found in the air stream about 300 mm (12
in) behind the end of the chaffer. If too little air is being
used or the shoe is over loaded, the grain will be carried
out with bunches of chaff and can be found at the end of
the chaffer. The tailings are returned through the
accelerator rolls for cleaning again, to prevent grain
damage.
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