RA 00048.pdf - OAR@ICRISAT

machines, abrasive elements are mounted hori
zontally on an axis and these function to remove
hull and beard particles from rye, wheat, etc. A
brush-type machine is available in four models (A
to D) and operates like the dehuller-scourer. The
abrasive-elements are replaced by a brush-type
cylinder mounted on a horizontal shaft. Machine
weights vary from 175 to 230 kg and throughputs
range from 600 to 2000 kg/hr. A combined
dehuller-brush type machine has both abrasive
elements (2/3) and brush-type cylinders (1/3)
mounted on a horizontal rotor.
Wondergrain Jaybee
The abrasive action of the Wondergrain Jaybee
dehuller (Jaybee Engineering Pty, Ltd.. 227
Princes Highway, Mail Box 168, Dandenong,
Victoria 3175, Australia) is provided by four metal
disks with abrasive material glued to both faces
(Fig. 1). These disks rotate at 2940 rpm on a
horizontal shaft within an octagonal basket made
from a metal screen. The basket rotates at an
approximate speed of 20 rpm in the direction
opposite to that of the disks. Fines pass through
the metal screen of the basket and are aspirated
into a cyclone. A belt of compressed air keeps the
holes in the screen clear of fines. The front panel
of the basket serves as the door for exiting grains.
The machine is used on a batch basis. Munier
(1980) found that with wheat, as the load was
increased from 12 to 20 kg, the yield decreased
from 80.7 to 61.8% after 3 min of dehulling. When
the retention time of a 12 kg sample was varied
from 30 sec to 2 min 30 sec, the yield decreased
from 95 to 76%.
FAO (Fondateur de I'atelier de I'Quest)
Eurafric M-164
The abrasive action of the FAO Eurafric dehuller
(distributed by Societe Comia-Fao S.A., 27, Bd de
Chateaubriant, 35500 Vitre, France) is provided by
a rubber cone rotating within an emery coated
enclosure (Fig. 2). The distance between the cone
and the emery surface is variable and depends on
the size of the grain. Following dehulling, the light
bran and dust are removed by a screening
apparatus. The larger bran particles are removed
by air aspiration.
The major variable affecting the degree of
dehulling is the number of times the grain is
passed through the machine. The distance between
the cone and the abrasive surface seems
to be of secondary importance. After six passes.
Munier (1980) found that the yield of wheat was
66.7%. For millet, using three passes the throughput
was in the order of 150 kg/hr.
Decomatic
The abrasive action of the Decomatic dehuller
(Fig. 3) manufactured by Bernhard Keller AG,
Herostrasse 9, CH-8048 Zurich, Switzerland, is
provided by five polishing disks mounted on a
vertical rotor (G). Grain flows from the glass
cylinder over a cone (A) which distributes the grain
evenly into the decortication space. The polishing
disks (E) rotate within a cylinder of perforated
sheet-metal (C). Two decortication cylinders (D)
are located lengthwise to the metal cylinder
providing a mechanism whereby the degree of
decortication can be adjusted. To separate the
fines from the dehulled grains, a strong current of
air enters at (B) and blows the fines through the
screen and finally into the air exit (J) and to the
ventilator. All around the millstones, at the base of
the screen, there are several segment-like sliding
valves which are adjustable from the outside by
micrometer screws (F). This adjustment regulates
the throughput. Following decortication, grains
leave the machine through the discharge channel
(L). The machine is driven by a 20 hp electric
motor (H) through a V-belt drive (K). The machine
dehulls a variety of cereals and legumes and
Munier (1980) reported that 47 machines had
been installed in five countries.
Perten et al. (1978) tested the Decomatic on
sorghum and found a negative, linear relationship
between the throughput (kg/hr) plotted on a log
scale and the decortication rate. Throughputs
were decreased at lower rotor speeds. The
number of broken kernels increased linearly with
the decortication rate. At lower rotor speeds, the
number of broken kernels was dramatically re
duced. The rapid reduction of fat, ash, and protein
content at low rotor speeds suggested that the
peripheral layers of the seed (germ, pericarp,
aleurone layer) were removed more efficiently
than at high rotor speeds. Most of the relationships
found by Perten et al. (1978) are probably
applicable to a variety of abrasive-type dehullers.
Vertical Shelling Machine Type-270
This dehuller (Fig. 4) manufactured by F. H. Schule
549