Machine-crop parameters affecting performance of an axial-flow soya bean thresher


Vejasit, A.; Salokhe, V.M.

AMA, Agricultural Mechanization in Asia, Africa and Latin America 37(3): 32-38

2006


A soyabean threshing unit was fabricated to study the effect of machine crop variables. This study was conducted at the Agricultural Engineering Division of the Department of Agriculture, Bangkok, Thailand. A peg-tooth drum was used for the study. Four levels of drum speeds (400, 500, 600 and 700 rpm m/second), three levels of feed rates (360, 540 and 720 kg (plant)/h) and three levels of soyabean moisture contents (32.88, 22.77 and 14.34% wb) were used for testing. The threshing efficiency varied from 98 to 100%. The grain damage and grain loss were less than 1 and 1.5%, respectively. The maximum power requirement was 2.29 kW at grain moisture content of 32.88% and at the drum speed of 700 rpm. The feed rate of 720 kg (plant)/h and 600 to 700 rpm drum speed gave highest output capacity, highest threshing efficiency, lowest grain damage and lowest grain losses. This unit will be later used on an axial-flow soyabean seed combine harvester.

Machine-Crop
Parameters
Affecting
Performance
of
an
Axial-Flow
Soya
Bean
Thresher
by
Anusorn
Vejasit
Doctor
Student
Agricultural
Systems
and
Enginnering,
School
of
Environment,
Resources
and
Devvelopment,
Asian
Institute
of
Technology,
Bangkok
THAILAND
Vilas
M.
Salokhe
Professor
Agricultural
Systems
and
Enginnering,
School
of
Environment,
Resources
and
Devvelopment,
Asian
Institute
of
Technology,
Bangkok
THAILAND
Abstract
A
threshing
unit
was
fabricated
to
study
the
effect
of
machine
crop
variables.
A
peg-tooth
drum
was
used
for
the
study.
Four
levels
of
drum
speeds,
three
levels
of
feed
rates
and
three
levels
of
soya
bean
moisture
contents
were
used
for
testing.
The
threshing
efficiency
varied
from
98
to
100
%.
The
grain
damage
and
grain
loss
were
less
than
1
and
1.5
%,
respectively.
The
maximum
power
requirement
was
2.29
kW
at
grain
moisture
content
of
32.88
%
and
at
the
drum
speed
of
700
rpm.
The
feed
rate
of
720
kg
(plant)/h
and
600
to
700
rpm
drum
speed
gave
highest
output
capacity,
highest
threshing
efficiency,
lowest
grain
damage
and
lowest
grain
loss-
es.
This
unit
will
be
later
used
on
an
axial-flow
soya
bean
seed
combine
harvester.
Introduction
Axial-flow
peg-tooth
cylinder
threshers
are
widely
used
in
Thai-
land.
Some
of
them
have
been
modified
to
be
used
with
rice
com-
bine
harvesters.
Currently
there
are
about
100,000
threshing
units
being
used
in
the
country.
These
thresh-
ers
are
used
to
thresh
many
kinds
of
grains
such
as
paddy,
mung
beans,
and,
also,
soya
beans.
Soya
bean
consumption
each
year
in
Thailand
is
increasing.
To
meet
the
increasing
demand,
Thailand
must
import
soya
beans.
In
1993,
the
domestic
need
for
soya
beans
was
611,000
tons
and
increased
to
812,000
tons
in
1998
(OAE,
1999).
The
Thai
government
has
given
high
priority
to
increased
production
of
soya
beans
by
encouraging
farm-
ers
to
increase
the
area
under
soya
bean
production.
Use
of
mechanical
harvesting
of
soya
beans
has
been
considered
advisable
because
of
the
current
agricultural
labor
short-
age
in
Thailand
for
harvesting
the
increased
area.
The
development
of
a
soya
bean
combine
harvester
has,
therefore,
become
of
para-
mount
importance.
The
threshing
unit
plays
a
key
role
in
determining
the
performance
of
a
combine
har-
vester.
Therefore,
the
objective
of
this
study
was
to
develop
a
suitable
peg-tooth
type
threshing
drum
and
optimize
its
working
parameters
by
studying
the
effects
of
drum
speed,
and
feed
rate,
moisture
content
on
the
threshing
performance.
Literature
Review
Several
impact
devices
have
been
designed
to
evaluate
the
effect
of
impact
velocity
on
soya
bean
seed
quality
(Cain
and
Holmes,
1977;
Bartsch
et
al,
1979;
Paulson
et
al,
1978).
Cain
and
Holmes
(1977)
evaluated
the
impact
damage
to
soya
bean
seeds
as
a
result
of
a
single
high-speed
collision
with
a
steel
plate.
They
concluded
that
impact
damage
is
dependent
on
both
seed
moisture
content
and
the
velocity
of
impact.
Bartsch
et
al
(1979)
reported
that
the
threshing
and
conveying
operations
during
harvest
consisted
of
dynamic
events
often
involving
a
large
momentum
exchange
dur-
ing
collisions
of
seeds
with
machine
components
and
other
seeds.
Paulsen
et
al
(1978)
stated
that
the
common
cause
of
damage
in
all
grain-han-
dling
studies
is
the
particle
velocity
immediately
before
impact
and
the
rigidity
of
the
surface
against
which
the
impact
occurs.
The
percentage
of
splits
and
fine
material
increased
as
the
impact
velocity
increased
and
the
seed
moisture
decreased
from
17
to
8
%.
The
seed
that
had
low
per-
centages
of
splits
after
impact,
also,
had
a
high
germination
standard.
Nave
(1979)
reported
that
a
seed
32
AGRICULTURAL
MECHANIZATION
IN
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AND
LATIN
AMERICA
2006
VOL.37
NO3
Fig.
1
Soya
bean
threshing
unit
(a)
and
instruments
for
power
measurement
(b)
,
6
A
(a)
producer
must
be
concerned
with
maintaining
threshing
and
separat-
ing
efficiency
while
avoiding
undue
impact
damage
to
the
seed.
Efforts
to
reduce
threshing
damage
while
increasing
capacity
have
resulted
in
the
development
of
rotary
threshing
equipment.
Newberg
et
al
(1980)
evaluated
the
damage
to
soya
beans
caused
by
rotary
and
conventional
threshing
mechanisms.
Three
dif-
ferent
combines,
a
single-rotor
machine,
a
double-rotor
machine,
and
a
conventional
rasp-bar
cyl-
inder
machine,
were
tested
under
field
conditions
at
four
peripheral
velocities.
The
seed
splits
were
sig-
nificantly
higher
for
the
conventional
cylinder
than
for
the
other
two
at
similar
peripheral
speeds.
The
per-
centage
of
splits
increased
as
the
pe-
ripheral
threshing
speed
increased
for
all
three
threshing
mechanisms;
however,
the
increase
in
splits
was
less
with
the
rotary
threshing
mechanisms
than
the
conventional
cylinder
threshing.
The
separation
losses
with
the
rotary
combine
were
significantly
higher
at
the
slowest
rotor
speed.
Dauda
(2001)
evalu-
ated
a
manually
operated
cowpea
thresher
for
small-scale
farmers
in
northern
Nigeria.
The
threshing
ef-
ficiency
was
84.1
to
85.9
%
and
seed
damage
was
1.8
to
2.3
%.
Vejasit
(1991)
compared
the
performance
of
the
rasp-bar
and
peg-tooth
thresh-
ing
drums
of
an
axial
flow
thresher
for
the
soya
bean
crop.
The
results
indicated
that
the
amount
of
grains
retained
on
the
threshing
unit
for
both
cylinders
at
all
cylinder
speeds
and
feed
rates
were
not
significantly
different.
Rani
et
al
(2001)
studied
on
a
plot
combine
to
thresh
a
seed
crop
of
chickpeas.
The
maximum
threshing
efficiency
was
97.2
%
at
8.9
%
seed
moisture
content
and
at
10.1
m/s
cylinder
speed.
Mesquita
and
Hanna
(1995)
reported
that
the
force
required
to
open
a
soya
bean
pod
was
remarkably
smaller
than
the
force
required
to
uproot
plants
and
to
detach
pods
from
the
stem.
Materials
and
Methods
This
study
was
conducted
at
the
Agricultural
Engineering
Division
of
the
Department
of
Agriculture,
Bangkok,
Thailand.
The
soya
bean
threshing
unit
was
developed
by
modifying
the
rice
thresher
that
is
normally
used
(Fig.
la).
The
thresh-
ing
unit
consisted
mainly
of
a
com-
mercially
available
main
frame,
tray,
threshing
drum,
concave,
sepa-
rating
and
cleaning
units,
conveyor
and
a
power
drive
unit.
It
operated
on
the
principle
of
axial
flow
move-
ment
of
the
material.
The
threshing
mechanism
consisted
of
a
threshing
drum
rotating
inside
a
two-section
concave.
The
threshing
drum
was
of
peg-tooth
type
having
an
open
threshing
drum.
The
diameter
and
length
of
the
threshing
drum
were
420
mm
and
930,
mm,
respectively.
The
concave
was
made
up
of
a
mild
steel
rod
with
rod
spacing
of
25
mm.
The
concave
clearance
be-
tween
the
threshing
drum
and
con-
cave
was
fixed
at
40
mm.
A
tractor
PTO
powered
the
thresher
and
the
tractor
engine
throttle
set
the
speed.
The
power
was
transmitted
to
the
threshing
drum
by
V-belts
(Fig.
lb).
Four
drum
speeds,
400,
500,
600
and
700
rpm
and
three
feed
rates
360,
540
and
720
kg
(plant)/h
were
used
for
testing.
The
four
drum
speeds
were
equivalent
to
a
periph-
eral
velocity
of
8.80,
10.99,
13.19
and
15.39
m/s,
respectively.
Mate-
rial
was
loaded
onto
the
tray
and
fed
into
the
threshing
unit.
The
average
moisture
contents
of
grain
(plant)
used
in
this
test
were
32.88
(29.09)
%
(w.b.),
22.77
(18.72)
%
(w.b.)
and
14.34
(16.78)
%
(w.b.).
The
most
commonly
grown
soya
bean
variety,
KKU-35,
was
used
for
testing.
The
crop
was
harvested
by
the
tradition-
al
method.
The
moisture
content
of
grain
and
plant
was
determined
by
the
oven
dry
method
(ASAE,
1983).
The
average
grain-straw
ratio
of
the
crop
was
1.23.
A
proximity
switch
measured
the
threshing
drum
speed
with
a
1-tooth
iron
sprocket
attached
with
the
threshing
drum
shaft
near
the
slip
ring
of
the
torque
transducer.
Threshing
drum
speed
was
mea-
sured
by
using
a
digital
tachometer.
In
this
experiment,
the
torque
trans-
ducer
with
strain
gage
type
KFG-
2-350-D2-11
was
used
(Fig.
ib).
A
digital
dynamic
strain
amplifier
was
used
to
amplify
the
output
sig-
nals
received
from
the
transducer
and
they
were
recorded.
A
personal
computer
was
used
to
control
the
in-
strument
system,
transfer
and
data
analysis.
The
power
requirement
was
calculated
from
the
torque
and
speed
data.
All
sensors
were
cali-
brated
before
the
use.
The
performance
evaluation
of
the
developed
thresher
was
assessed
in
terms
of
output
capacity,
threshing
efficiency,
grain
damage,
grain
loss-
es
and
power
requirement
(RNAM,
1995).
The
performance
of
the
soya
bean
threshing
unit
was
analyzed
at
different
moisture
contents,
drum
speeds
and
feed
rates
by
using
a
randomized
complete
block
design
(RCBD)
of
a
3
x
4
x
3
factorial
experiment
with
three
replications
VOL.37
NO3
2006
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA,
AND
LATIN
AMERICA
33
in
each
treatment.
A
comparison
between
treatment
means
was
made
by
the
least
significant
difference
(LSD)
at
the
5
%
level
(Box
et
al,
1978;
Gomez
and
Gomez,
1984).
Results
and
Discussion
Capacity
Figure
2
shows
the
effect
of
drum
speed
on
capacity
at
different
feed
rates
and
moisture
contents.
The
capacity
rapidly
increased
with
an
increase
in
the
drum
speed
for
all
feed
rates
and
grain
moisture
con-
tents.
The
maximum
capacity
was
obtained
at
the
highest
feed
rate
of
720
kg
(plant)/h,
14.34
%
(w.b.)
grain
moisture
content
and
700
rpm
drum
speed.
The
capacity
at
a
feed
rate
of
720
kg/h
was
higher
than
at
other
feed
rates
throughout
the
range
of
drum
speeds
and
moisture
contents
tested.
At
the
feed
rate
of
720
kg/h,
the
capacity
at
14.34,
22.77
and
32.88
%
(w.b.)
grain
mois-
ture
content
increased
from
143.80
to
214.17,
141.79
to
204.74
and
139.70
to
195.30
kg/h,
respectively,
(Fig.
2)
as
drum
speed
increased
from
400
to
700
rpm.
As
feed-rate
increased,
capacity
increased
at
all
Capacity,
kg/h
Grain
damage,
%
250
1.5
Grain
(Plant)
=
32.88
(29.09)
%
(w.b.)
Grain
(Stem)
=
32.88
(29.09)
%
(w.b.)
200
1.0
150
0.5
100
50
400
500
600
700
0.0
400
500
600
700
250
1.5
Grain
(Plant)
=
22.77
(18.72)
%
(w.b.)
Grain
(Stem)
=
22.77
(18.72)
%
(w.b.)
200
1.0
150
0.5
100
---------------
1----
--
'
50
400
500
600
700
0.0
400
500
600
700
250
1.5
Grain
(Plant)
=
14.34
(16.78)
%
(w.b.)
Grain
(Stem)
=
14.34
(16.78)
%
(w.b.)
200
1.0
150
0.5
100
50
t
-
-------
0.0
400
500
600
700
Drum
speed,
rpm
360kg/h
540kg/h
A
720kg/h
Fig.
2
Effect
of
drum
speed
on
capacity
at
different
grain
moisture
contents
and
feed
rates
400
500
600
700
Drum
speed,
rpm
360kg/h
540kg/h
720kg/h
Fig.
3
Effect
of
drum
speed
on
grain
damage
at
different
grain
moisture
contents
and
feed
rates
34
AGRICULTURAL
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AND
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2006
VOL.37
NO3
Table
1
ANOVA
of
the
soya
bean
threshing
unit
performances
Source
of
variation
df
F-value
Capacity
Threshing
efficiency
Grain
damage
Grain
loss
Replication
2
Moisture
content
(A)
2
33.97**
3.92*
37.15**
52.03**
Feed
rate
(B)
3
217.56**
3.90*
16.11**
3.94*
Drum
speed
(C)
3
213.10**
58.78**
18.39**
25.93**
AB
6
4.77**
0.72
ns
4.51**
0.07
ns
AC
6
1.28
ns
1.32
ns
3.35** 3.13**
BC
9
6.00**
1.47
ns
2.85**
1.39
ns
ABC
18
1.31
ns
0.84
ns
0.99
ns
1.55
ns
Error
94
**:
highly
significant
an
1
%
level,
*:
significant
at
5
%
level,
ns:
non
significant,
df:
degrees
of
freedom
drum
speeds
and
moisture
contents.
The
capacity
at
500,
600
and
700
rpm
gradually
increased
when
the
feed
rate
was
increased
from
360
to
720
kg
(plant)/h
at
22.77
to
32.88
%
(w.b.)
moisture
content.
At
all
feed
rates
and
drum
speeds,
the
capacity
slightly
decreased
as
the
moisture
content
decreased.
The
analysis
of
variance
showed
that
the
main
effects
of
the
moisture
content
(A),
feed
rate
(B)
and
drum
speed
(C)
were
significant
on
the
threshing
capacity
at
thel
%
level
of
significance
(Table
1).
The
effect
of
drum
speed
and
feed
rate
were
the
most
significant.
Among
the
first
order
interactions,
moisture
content
and
feed
rate,
along
with
feed
rate
and
drum
speed,
showed
highly
significant
effects
on
the
thresher
capacity.
Comparison
among
treat-
ment
means
using
the
least
signifi-
cance
difference
(LSD)
showed
that,
at
720
kg
(plant)/h
feed
rate,
the
capacity
was
not
significantly
dif-
ferent
from
the
grain
moisture
con-
tent
at14.34
and
22.77
%
(w.b.).
The
capacity
at
500,
600
and
700
rpm
drum
speeds
was
not
significantly
different
when
the
feed
rate
was
varied
from
360
to
720
kg
(plant)/h.
The
capacity
at
540
and
720
kg/h
feed
rates
showed
a
similar
trend
and
was
not
significantly
different
at
the
drum
speeds
of
600
to
700
rpm.
Grain
damage
Figure
3
shows
the
effect
of
drum
speed
on
grain
damage
at
different
grain
and
stem
moisture
contents,
and
feed
rates.
The
percentage
of
grain
damage
slightly
increased
with
an
increase
in
drum
speed
at
32.88
%
(w.b.)
grain
moisture
con-
tent
for
all
feed
rates.
At
14.34
to
22.77
%
(w.b.)
grain
moisture
con-
tent,
the
grain
damage
was
between
0.07
to
0.68
%
for
all
feed
rates
and
drum
speeds.
Grain
damage
slightly
decreased
with
an
increase
in
feed
rate.
Grain
damage
increased
as
the
grain
moisture
content
was
increased
from
14.34
to
32.88
%
(w.b.).
However,
the
grain
damage
was
less
than
1.5
%
at
all
moisture
contents,
feed
rates
and
drum
speed
combinations.
The
analysis
of
vari-
ance
of
the
main
effects
of
moisture
content,
feed
rate
and
drum
speed
showed
significant
effects
on
grain
damage
at
the
the
1
%
level
of
sig-
nificance.
Among
the
first
order
interactions,
moisture
content
and
feed
rate,
feed
rate
and
drum
speed,
and
moisture
content
and
drum
speed
showed
significant
effect
on
the
grain
damage.
Threshing
Efficiency
Test
results
indicated
that
thresh-
ing
efficiency
was
between
98.35
to
99.49
%
(Fig.
4).
This
was
due
to
low
pod
cohesion
at
the
range
of
soya
bean
moisture
contents
tested.
This
might
have
resulted
in
high
threshing
efficiency.
Table
1
shows
that
drum
speed,
feed
rate
and
mois-
ture
content
significantly
affected
threshing
efficiency
at
the
1
%,
5
%
and
5
%
level
of
significance,
respectively.
Comparison
among
treatment
means
using
LSD
showed
that,
at
14.34
to
32.88
%
(w.b.)
grain
moisture
with
600
to
700
rpm
drum
speeds
and
a
feed
rate
of
720
kg
(plant)/h,
the
threshing
efficiency
did
not
differ
significantly.
Grain
Losses
Figure
5
shows
the
effect
of
drum
speed
on
grain
loss
at
differ-
ent
grain
moisture
contents
and
feed
rates.
Grain
loss
at
32.88
and
22.77
%
(w.b.)
moisture
content
rapidly
decreased
with
an
increase
in
drum
speed
from
400
to
600
rpm.
But,
it
rapidly
increased
with
further
in-
crease
in
drum
speed
from
600
to
700
rpm
at
all
feed
rates.
At
14.34
%
(w.b.)
grain
moisture
content,
grain
loss
slightly
decreased
with
an
in-
crease
in
drum
speed
of
400
to
700
rpm.
Grain
loss
rapidly
increased
with
an
increase
in
grain
moisture
content
from
14.34
to
32.88
%
(w.b.)
at
all
feed
rates.
The
grain
loss
was
between
0.49
to
1.03
%
when
the
drum
speed
was
varied
from
500
to
600
rpm
at
14.34
to
22.77
%
(w.b.)
grain
moisture
content.
Table
1
shows
that
the
effect
of
moisture
content,
feed
rate
and
drum
speed
on
grain
loss
were
sig-
nificant
at
1
%,
5
%
and
1
%
levels
of
significance,
respectively.
The
interactions
between
moisture con-
tent
and
drum
speed
on
grain
loss
were
also
significant
at
the
1
%
level
of
significance.
Comparison
be-
tween
treatment
means
of
grain
loss
showed
that
the
grain
losses
did
not
differ significantly
at
grain
mois-
ture
content
of
14.34
and
22.77
%
(w.b.)
at
500
rpm
and
600
rpm
drum
speeds.
Power
Requirement
The
power
required
for
the
soya
bean
threshing
unit
at
different
drum
speeds,
seed
moisture
contents
and
feed
rates
is
shown
in
Figure
6.
The
power
requirement
of
the
thresh-
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AGRICULTURAL
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IN
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AND
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35
ing
unit
increased
as
the
speed
of
the
threshing
drum,
feed
rate
and
crop
moisture
content
increased.
These
increases
were
due
to
greater
compression
of
the
material
and
increased
friction
between
crop
ma-
terial
and
the
threshing
system.
The
average
power
requirement
at
540
to
720
kg
(plant)/h
feed
rates
at
14.34
%
(w.b.)
grain
moisture
content
was
between
0.89
to1.85
kW
when
the
drum
speed
was
increased
from
500
to
700
rpm
(11.00
to
15.40
m/s).
However,
it
was
observed
that
the
maximum
power
requirement
was
2.29
kW
at
grain
moisture
content
of
32.88
%
and
at
a
drum
speed
of
700
rpm.
Conclusions
a.
The
moisture
content,
feed
rate
and
threshing
drum
speed
af-
fected
the
output
capacity,
thresh-
ing
efficiency,
grain
damage
and
grain
losses
during
soya
bean
threshing.
b.
The
capacity
of
the
peg-tooth
open
threshing
drum
varied
from
144
to
214
kg/h
at
all
drum
speeds
and
feed
rates.
The
threshing
ef-
ficiency
was
found
to
be
in
the
range
of
98.00
to
100
%
for
all
Threshing
efficiency,
%
100
99
98
97
96
Grain
(Stem)
=
32.88
(29.09)
%
(w.b.)
95
400
500
600
700
100
99
98
97
96
Grain
(Stem)
=
22.77
(18.72)
%
(w.b.)
95
400
500
600
700
100
99
98
97
96
Grain
(Stem)
=
14.34
(16.78)
%
(w.b.)
95
400
500
600
700
Drum
speed,
rpm
360kg/h
540kg/h
--
-
A
---
720kg/h
Fig.
4
Effect
of
drum
speed
on
threshing
efficiency
at
different
grain
moisture
contents
and
feed
rates
Grain
losses,
%
4—
3
2
'',..
1
Grain
(Stem)
=
32.88
(29.09)
%
(w.b.)
0
400
500
600
700
4
Grain
(Stem)
=
22.77
(18.72)
%
(w.b.)
3
2
.................
1
0
400
500
600
700
4
Grain
(Stem)
=
14.34
(16.78)
%
(w.b.)
3
2
1
.....
.......
---------
0
400
500
600
700
Drum
speed,
rpm
360kg/h
540kg/h
-
A
-
-
720kg/h
Fig.
5
Effect
of
drum
speed
on
grain
losses
at
different
grain
moisture
contents
and
feed
rates
36
AGRICULTURAL
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AND
LATIN
AMERICA
2006
VOL.37
NO3
moisture
contents,
feed
rates
with
c.
For
better
performance
of
the
drum
speeds
varying
from
500
to
tested
threshing
unit,
a
peg-
700
rpm.
The
grain
damage
was
tooth
drum
at
a
speed
range
of
lower
than
1
%.
600
to
700
rpm
(13.2
to
15.4
m/s)
2.5
2.0
1.5
1.0
0.5
Feed
rate
720
kg/h
0.0
10
20
30
40
Seed
moisture
content,
%
(w.b.)
400kg/h
500kg/h
---
A
---
600kg/h
700kg/h
Power
requirement,
kW
2.5
2.0
1.5
1.0
__----
__
------
___
.
--------------
i -
-
0.5
M.C.
14.34
%
(w.b.)
0.0
400
500
600
700
Drum
speed,
rpm
400kg/h
500kg/h
-
600kg/h
2.5
2.0
1.5
A-
- -
- -
-
-
-
-
ai-
-------------
----
A
1.0
S
-- -----------
S
0.5
M.C.
14.34
%
(w.b.)
0.0
300
400
500
600
700
800
Feed
rate,
kg/h
-•-•
400kg/h
500kg/h
600kg/h
700kg/h
Fig.
6
Effect
of
drum
speed,
seed
moisture
content
and
feed
rate
on
power
requirement
of
a
soya
bean
threshing
unit
and
a
feed
rate
of
540
to
720
kg
(plant)/h
should
be
used.
The
out-
put
capacity,
threshing
efficiency,
grain
damage
and
grain
loss
at
700
rpm
(15.4
m/s)
drum
speed
and
720
kg
(plant)/h
feed
rate
were
214
kg/h,
99.49
%,
0.22
%
and
0.80
%,
espectively.
d.
The
average
power
requirement
was
1.85
kW
at
feed
rate
of
720
kg
(plant)/h,
14.34%
(w.
b.)
grain
moisture
content
and
at
a
drum
speed
of
700
rpm
(15.40
m/s).
e.
For
the
design
of
a
soya
bean
combine
harvester
with
peg-tooth
type
drum,
the
speed
should
be
in
the
range
of
13.2
to
15.4
m/s.
The
grain
moisture
content
should
be
in
the
range
of
13
to
15
%
during
harvesting
of
soya
beans
by
the
combine
harvester.
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(1983).
Moisture
Measure-
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Standard
5410.
Agri-
cultural
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Bartsch,
J.
A.,
C.
G.
Haugh,
K.
L.
Athow
and
R.
M.
Peart
(1979).
Impact
damage
to
Soya
bean
seed.
ASAE
Paper
79-3037.
American
Society
of
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St.
Joseph,
MI.
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G.
E.,
Hunter,
W.
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New
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Cain,
D.
F.
and
R.
G.
Holmes
(1977).
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bean
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impact
damage.
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American
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St.
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Dauda,
A.
(2001).
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northern
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Gomez,
K.
A.
and
A. A.
Gomez.
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kW
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AMERICA
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■■
New
Co-operating
Editor
Chetem
Wangchen
Programme
Director
Agriculture
Machine
Centre
Ministry
of
Agriculture
Royal
Government
of
Bhutan
Bondey
Paro
Bhutan,
P.O.Box
1228
E-mail:
38
AGRICULTURAL
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