RA 00048.pdf - OAR@ICRISAT

Hopper
Dehuller
Motor
Rubber
cone
Emery-coated
surface
Air separator
Sifting apparatus
Brushes
Screen
Seed c o a t s
D e h u l l e d grain
Fine particles
Figure 2. Schematic diagram of the FAO Eurafric dehuller. (Adapted from Munier 1980.)
extensive modification of the George Hill grain
thresher (Reichert 1977). The abrasive action is
provided by 13 carborundum stones (30.5 cm in
diameter x 3.2 cm thick) or 27 resinoid disks (30.5
cm in diameter x 0.64 cm thick) mounted on a
horizontal axis (Fig. 5). When the feed gate is
opened, grain flows from the hopper into the body
of the machine. Fines generated by the action of
the abrasive surface are taken off by the fan and
are eventually bagged at a cyclone. Dehulled grain
exits via an overflow outlet. Throughput is adjusted
by regulating the feed gate and the
adjustable gate on the overflow outlet. Throughputs
with sorghum were about 300 and 550 kg/hr
at extraction rates of 70 and 85%, respectively,
when a stone speed of 1050 rpm was used
(Reichert and Youngs 1976). Using a softer
sorghum, throughputs in the order of 900 kg/hr
were obtained with a stone speed of 1300 rpm
and an extraction rate of 7 2 % (Oomah et al.
1981a).
The PRL dehuller was modified at the Rural
Industries Innovation Centre (RIIC) in Botswana to
process grain in either a continuous or batch
operation. The modified machine (PRL/RIIC) is
presently manufactured by RIIC, Nutana Machine
Co. and Ackroyd Construction Ltd. The PRL/RIIC
dehuller has a hinged door at the bottom of the
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