Development of an axial-flow thresher with multi-crop potential


Singhal, O.P.; Thierstein, G.E.

Agricultural Mechanization in Asia, Africa and Latin America 18(3): 57-65

1987


Commonly available wheat threshers in India are not suitable for handling a wide range of crops grown by the farmers, particularly moisture crops. An IRRI axialflow thresher, a better design, capable of threshing freshly harvested paddy was selected, modified and evaluated as a multicrop thresher for a wide range of crops, namely; sorghum, millet, chickpea, pigeonpea, wheat and paddy at ICRISAT Centre in India and in villages. A threshing efficiency of more than 95% and grain output of 500-800 kg/ha, were obtained for most of the crops. This thresher could be recommended for village adoption based on its performance and other features.

Development
of
an
Axial-Flow
Thresher
with
Multi-Crop
Potential
by
O.P.
Singhal
Senior
Scientist
Division
of
Agric.
Engg.
I.A.R.I.
New
Delhi-110012,
India
Abstract
Commonly
available
wheat
threshers
in
India
are
not
suitable
for
handling
a
wide
range
of
crops
grown
by
the
farmers,
particularly
moisture
crops.
An
IRRI
axial-
flow
thresher,
a
better
design,
capable
of
threshing
freshly
harvested
paddy
was
selected,
modified
and
evaluated
as
a
multi-
crop
thresher
for
a
wide
range
of
crops,
namely;
sorghum,
millet,
chickpea,
pigeonpea,
wheat
and
paddy
at
ICRISAT
Centre
in
India
and
in
villages.
A
threshing
ef-
ficiency
of
more
than
95%
and
grain
output
of
500-800
kg/ha,
were
obtained
for
most
of
the
crops.
This
thresher
could
be
recommended
for
village
adoption
based
on
its
performance
and
other
features.
Introduction
Threshing
involves
the
detach-
ment
of
grain
kernels
from
the
panicles.
It
is
one
of
the
most
important
post-harvest
operations
for
cereals.
Hand-beating
and
bul-
lock-treading
of
the
harvested
crops
have
been
the
traditional
methods
for
threshing
crops
in
India.
The
output
of
these
methods
is
low
leading
to
delays
in
handling
a
large
volume
of
produce
and
con-
sequent
losses,
while
the
cost
of
operation
is
high
(Singh
and
Joshi,
1979).
Power
threshers
have
be-
come
popular
in
India
to
overcome
these
difficulties.
The
present
po-
pulation
of
the
threshers
in
the
country
is
estimated
to
be
over
500
000
with
an
annual
production
of
approximately
50
000
units
(Verma,
et
al,
1978).
Commonly
available
wheat
threshers
are
designed
primarily
on
hammer
mill
principles
and
are
designed
to
produce
chopped
straw
(Bhusa)
along
with
threshed
grain.
Farmers
use
this
chopped
wheat
straw
as
animal
feed.
These
thre-
shers
are
not
suitable
for
handling
other
crops
like
paddy,
maize,
sorghum
and
pulses.
For
these
crops
farmers
prefer
not
to
chop
the
straw.
The
energy
required
for
these
threshers
is
very
high:
ranging
from
20
to
50
kWh/ton
(Pathak,
et
al,
1978).
The
HYV
short
duration
sor-
ghum
and
pearl
millet
grown
as
major
cereal
crops
in
the
semi-
arid
tropics
of
India,
if
planted
in
June,
are
harvested
in
the
last
week
of
August
or
first
week
of
Sep-
tember,
months
of
high
probability
of
rainfall
(Virmani
et
al,
1978).
These
crops
are
difficult
to
thresh
at
high
moisture
content
by
con-
ventional
threshers
available
in
the
country.
A
suitable
thresher
is
re-
quired
to
thresh
these
crops
to
G.E.
Thierstein
Associate
Professor
Dept.
of
Agril.
Engg.
Kansas
State
University
2115
R.
Street,
Belleville
Kansas
66935,
U.S.A.
avoid
losses
from
rotting
and
other
causes.
Threshing
Mechanisms
The
important
threshing
me-
chanisms
used
in
threshers
are
given
in
Fig.
1.
The
simplest
and
most
widely
used
arrangement
is
a
threshing
cylinder
with
wire
loops
on
its
periphery
and
no
concave
(a).
The
grains
are
combed
out
easily
while
a
handful
of
material
is
held
against
the
wire
loops
of
the
re-
volving
cylinder.
It
is
generally
used
in
pedal
operated
threshers.
A
hammer-mill
or
beater
type
threshing
cylinder
(b)
is
used
in
wheat
threshers.
The
hammers
are
mounted
on
a
shaft
rotating
inside
a
closed
housing
or
drum.
The
crop
becomes
sufficiently
small
in
size
to
pass
through
the
concave
placed
at
the
bottom
of
the
housing.
A
similar
threshing
arrangement
(c)
is
used
in
syndicator
threshers
which
uses
a
serrated
flywheel
instead
of
hammers
for
grain
threshing.
The
flywheel
rotates
in-
side
a
closed
casing
and
concave.
The
material
makes
a
three
quarter
turn
during
which
threshing
occurs
before
encountering
the
chopping
knives
which
cut
the
straw
into
small
pieces.
The
crop
is
fed
axially
into
the
threshing
cylinder.
The
rasp
bar
(d)
and
the
angle
VOL.18
NO.3
1987
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
57
-WIRE
LOOP
FEEDING
CHAIN
THRESHING
CYLINDER
STALK
PUSHING
BAR
CONCAVE
(A)
WIRE
LOOP
ME
CHANISM
PERIFERY
TEETH
CHOPPING
KNIFE
FEED
CHUTE
CONCAVE
(C)
SYNDICATOR
MECHANISM
bar
(e)
cylinder
type
threshing
ar-
rangements
are
quite
common
(Bainer
et
al,
1960).
The
axial
flow
threshing
arrangement
(f)
has
been
developed
at
IRRI,
Philippines
and
is
quite
successful
for
paddy
threshing
(Araullo
at
al,
1976).
Sometimes
a
rubber
roll
threshing
mechanism
is
also
used
for
thresh-
ing
podded
crops
like
beans.
Those
rolls
seperate
the
grain
by
squeezing
action,
rubbing
action
or
a
com-
bination
of
the
two.
Criteria
for
Thresher
Selection
Multicrop
Potential
Mechanical
threshing
of
wheat
crop
is
widely
accepted
whereas
threshing
of
paddy
and
other
crops
is
still
usually
done
manually.
With
the
introduction
of
high
yielding
varieties,
fertilizers,
improved
equipment
and
better
farm
BEATER
CYLINDER
CASING
EE
DIND
CHUTE
CONCAVE
(B)
BEAT
ER
TYPE
MECHANISM
FEED
STRIPPER
0
CYLINDER
BAR
CONCAVE
(D)
RASP
BAR
MECHANISM
SPIKE
TOOTH
CYLINDER
CYLINDER
CASING
PUSH
IN
POINT
0
FEEDING
TRAY
CONCAVE
SPIKE
TOOTH
CYLINDER
practices,
multiple
cropping
is
be-
coming
popular
(Joshi,
et
al,
1980).
Since
most
Indian
farmers
have
a
land
holding
of
less
than
5
ha,
a
low
cost,
light-weight
thresher
with
few
moving
parts
and
with
a
multi-
crop
potential
is
preferred
by
the
farmers
(Pathak,
et
al,
1978).
Performance
Where
multiple
cropping
is
prac-
tised,
it
is
often
necessary
to
har-
vest
the
crop
at
or
soon
after
physiological
maturity
so
that
adequate
time
is
available
for
time-
ly
sowing
of
the
next
crop.
A
good
thresher
must
be
able
to
thresh
high-moisture
crops
efficiently
(minimum
threshing
efficiency
of
95%)
with
minimal
separation
losses.
The
threshed
grain
should
be
clean
and
with
the
least
amount
of
broken
grains.
Operation
Safety
A
survey
of
thresher
accidents
conducted
by
Verma,
et
al
(1978)
during
the
wheat
threshing
season
of
1976
reveals
that
wit
-
1
a
thresher
population
of
150
000
in
the
state
of
Punjab,
as
many
as
294
persons
were
injured
while
working
on
power
threshers.
The
percentage
of
accidents
for
various
types
of
threshers
is
given
in
Table
1
(Verma,
1978).
The
number
of
accidents
in
the
Punjab
increased
to
391
in
1978
and
396
in
1979
(Agricultural
Engineering
Today,
July-August,
1980).
Similarly
the
figures
for
the
state
of
Haryana
are
280
in
1977,
281
in
1978
and
127
in
1979.
It
has
been
reported
that
about
1
200
persons
are
being
incapacitated
by
the
use
of
poorly
designed
threshers
every
year
in
India.
Most
of
the
victims
are
the
poor
labourers
hired
for
this
job.
Similar
data
are
also
available
for
other
parts
of
the
country.
It
has
also
been
reported
that
threshers
with
rasp-bar
and
spike-tooth
cylinders
primarily
designed
for
paddy
threshing
are
quite
safe
in
operation
but
these
threshers
need
several
modifications
for
threshing
other
cereals
and
pulse
crops
ef-
ficiently.
Threshing
Characteristics
of
Crops
The
threshing
performance
de-
pends
upon
the
type
of
crop,
variety,
moisture
content
and
threshing
arrangement.
The
paddy
is
easy
to
thresh.
Trials
conducted
at
ICRISAT
on
different
threshers
available
from
India
and
abroad,
it
was
observed
that
certain
sorghum
geno-types
and
millets
are
very
Table
1
Thresher
Accidents
for
Various
Types
of
Threshers.
Type
Percentage
of
accidents
Drummy
45.16
Syndicator
type
37.42
Hammer
mill
type
14.19
Rasp
bar
1.94
Spike
tooth
1.29
Source:
Verma,
1978.
CYLINDER
CLEARANCE
ADJUSTMENT
RUBBER
COATED
ANGLE
BARS
O
FEEDING
CHAIN
RUBBER
CONCAVE
BARS
(E)
ANGLE
BAR
CYLINDER
MECHANJSM
(F
.
)
Fig.
1
Different
types
of
threshing
mechanism.
58
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
1987
VOL.18
NO.3
Table
2
Labor
and
Power
Requirements
for
Paddy
Threshing
and
Cleaning
Operations
Operation
Labor
requirement
(man-h/ha)
Mechanical
power
requirement
(kW)
Threshing
(A)
Manual
Threshing
with
hand
sticks
Pedal
thresher
150
300-400
Treading
with
bullocks
(2
men,
2
bullocks)
3*
(B)
Mechanical
Treading
with
standard
tractor
80
30-50
IARI
axial
flow
portable
thresher
54
3
IRRI
axial
flow
thresher
20
6
Cleaning
(A)
Manual
Winnowing
basket
100
Hand
operated
winnower
30-75
(B)
Mechanical
Seed
cleaner
24-28
0.5-1
*Capacity
(days/ha)
Source:
Araulle,
et
al.
1976.
difficult
to
thresh
at
a
moisture
content
higher
than
15%
which
is
most
common
at
the
time
of
har-
vesting
rainy
season
crops.
When
these
crops
are
threshed
at
high
moisture
levels,
the
result
is
that
a
considerable
amount
of
seeds
retain
their
glumes
(5
to
15%)
reducing
the
market
price
considerably
(20
to
25%)
(ICRISAT
Annual
Report,
1978-79).
The
pulse
crops
are
quite
delicate
to
thresh
and
results
in
higher
percentage
of
brokens
with
little
harsh
threshing
arrangement.
Labour
Requirements
If
harvesting,
threshing
and
cleaning
are
done
by
human
labour,
the
operations
require
a
large
number
of
man-hours.
Table
2
gives
the
labor
and
the
power
require-
ments
for
paddy
threshing
and
cleaning
operations
done
on
small
farms
using
various
methods.
The
table
shows
that
about
150
man-
h/ha
and
100
man-h/ha
are
the
labour
requirements
for
threshing
and
cleaning
by
manual
labor
as-
suming
a
crop
yield
of
4
000
kg/ha
for
paddy
crop.
While
only
20
man-
h/ha
are
required
for
threshing
and
cleaning
operation
using
a
6
kW
mechanical
thresher
(Araullo
et
al,
1976).
Walker
and
Khirsagar
(1981)
also
estimate
that
the
labour
re-
quirement
is
considerably
less
for
mechanical
threshing
than
manual
threshing.
Considering
the
above
facts,
a
suitable
multicrop
thresher
is
re-
quired
to
meet
the
following
requirements:
Performance
Capable
of
threshing
a
wide
range
of
crops;
Design
Simple,
can
be
locally
fabricated
in
small
scale
manufacturing
plants
and
opera-
tionally
safe;
Capacity
Approx.
400-600
kg/h
of
wheat
grain;
Power
10
kW-h/ton;
Weight
less
than
200
kg;
Labour
4-6
man-labours
to
operate
the
thresher;
Cost
About
Rs.8
000
with
prime
mover.
Brief
Description
of
Threshers
The
following
threshers
with
multicrop
potential
were
selected
for
evaluation
on
threshing
of
paddy,
sorghum,
millets,
chickpea
and
pigeonpea:
1)
IRRI
portable
thresher
without
cleaning
attach-
ments
and
using
3
kW
petrol
engine.
2)
Rasp-bar
type
Alvan
Blanch
midget
thresher
without
cleaning
attachment
with
2.25
kW
petrol
engine.
3)
IRRI
axial
flow
thresher
with
cleaning
attachments
and
using
7.5
kW
petrol
engine.
Fig.
2
IRRI
portable
thresher.
IRRI
Portable
Thresher
The
thresher
was
designed
to
satisfy
the
need
of
a
small
farmer
and
was
low-cost
thresher
that
could
be
carried
into
the
field.
The
thresher
(Fig.
2)
consisted
of
a
metal
frame,
a
peg-tooth
cylinder
with
four
straw
throwing
paddles
on
one
end,
semi-circular
cover
with
four
spiral
louvers,
and
a
round
bar
lower
concave.
A
folding
feeding
tray,
removable
handle
bars
for
transport
and
complete
with
a
3
kW
petrol
engine.
The
thresher
operates
on
the
axial-flow
principle.
The
material
is
fed
at
one
end
of
the
cylinder
and
is
discharged
through
the
other
end.
The
pegs
on
the
threshing
cylinder
hit
the
material,
separating
the
grain
from
the
straw
and
at
the
same
time
accelerating
them
around
the
cylinder.
The
bulk
of
the
grain
is
threshed
during
the
initial
im-
pact.
Further
threshing
is
per-
formed
while
the
material
moves
axially
until
the
straw
is
discharged
by
the
straw
paddles
at
the
dis-
charge
end.
The
original
design
provided
by
IRRI
was
suitable
for
threshing
paddy
but
this
thresher
could
not
be
used
to
thresh
sor-
ghum
and
millet.
The
thresher
has
no
provision
to
change
threshing
cylinder
concave.
Axial-Flow
Thresher
This
model
evolved
as
a
result
of
operational
and
cleaning
problems
encountered
in
an
earlier
design
of
the
portable
thresher
(Fig.
3).
VOL.18
NO.3
1987
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
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AMERICA
59
C
V
UVER
NNE!
NO
CY
AR
CONCAVE
THRE
RHINO
CANVASS
GAR
OP
COVER
STRAW
BLOWER
EDIMO
TRAY
(b)
CYLINDER
ft
CONCAVE
ARRANGEMENT
DLO
R
A
Pe
0
700114
TA
N.
RANSP
ENOIN
E)
C.)
SIDE
VIEW
(b)
FRONT
VIEW
Fig.
3
Axial-flow
thresher
with
cleaning
attachment.
HOOD
ENGINE
BE
LT
The
thresher
consisted
of
the
threshing,
cleaning
and
conveying
sections.
The
threshing
section
was
similar
to
the
earlier
design
but
with
an
open
peg-tooth
cylinder.
The
cover
was
semi-hexagonal
to
assist
in
the
separation
of
the
threshed
grain
from
the
straw
by
interrupting
its
smooth
circular
motion.
This
action
stirs
the
straw
to
improve
separation
efficiency.
The
concave
is
of
a
semi-circular
shape
made
from
round-bars
and
fixed
in
position.
The
cleaning
system
consists
of
upper
and
lower
oscillating
screens
and
twin
centrifugal
blowers
be-
tween
the
screens
which
provides
air
movement
to
clean
light-weight
material
from
the
grain
as
it
dropped
from
the
upper
screen.
The
screenes
moved
in
opposite
directions
at
the
frequency
of
340
oscillations/min
and
stroke
length
of
32
mm
providing
a
quiet
and
balanced
operation.
The
upper
and
lower
screens
are
replaceable
to
suit
various
cleaning
conditions
and
seed
sizes.
At
the
normal
blower
speed
of
750
rpm,
the
average
air
velocity
at
the
discharge
duct
was
427
m/min
with
the
air
control
shutters
fully
opened
and
323
m/min
in
the
closed
position.
This
range
of
air
velocities
was
found
sufficient
to
clean
threshed
paddy
under
a
wide
range
of
threshing
conditions
but
not
adequate
for
pearl
millet
and
sorghum.
The
clean
grain
was
conveyed
to
the
left
side
of
the
thresher
by
an
auger
mounted
under
the
lower
speeds
of
the
oscillating
sieve.
The
thresher
has
no
provision
to
change
the
speed
of
cylinder,
fan
and
oscillat-
ing
sieves
but
was
modified
to
change
the
speeds
of
these
com-
ponents.
Alvan
Blanch
Midget
Thresher
The
thresher
(Fig.
4)
is
very
simple
in
design.
It
consisted
of
a
30
cm
wide
triangular
section
threshing
drum
with
three
rasp
bars
TRAY
at
120
mm
spacing
and
a
fixed
bar
concave.
The
clearance
between
the
drum
and
concave
was
adjustable
by
sliding
the
drum
shaft
bearings
vertically
and
by
spacers
in
the
bearing
mountings
which
displaced
it
horizontally.
The
thresher
has
no
provision
for
cleaning
and
separation
of
grains
from
chaff,
consequently
the
output
was
mixed
with
chaff.
A
stationary
straw
rack
was
provided
to
separate
the
straw
and
with
additional
cleaning,
it
worked
satis-
factorily
for
paddy
and
sorghum
threshing
but
was
not
suitable
for
millets,
groundnut
and
maize.
It
was
a
small
thresher
using
a
BELT
GUARD
BELT
ADJUSTER
FEEDING
HOPPER
THRESHING
DRUM
2.25
kW
power
unit
for
its
opera-
tion.
The
thresher
was
safe
in
operation.
Three
persons
were
re-
quired
to
operate
it
(two
for
feed-
ing
the
earheads
and
one
for
collecting
the
threshed
material).
LCT
Thresher
This
thresher
(Fig.
5)
is
claimed
suitable
for
threshing
sorghum
crop.
The
manufacturer
agreed
to
put
the
thresher
for
testing
on
a
wide
range
of
crops.
The
thresher
consists
of
a
rasp
bar
type
open
cylinder
and
a
standard
wire
concave.
The
ma-
terial,
after
threshing,
passed
to
the
O
DRUM
ADJUSTER
C
CAVE
SECTION
THROUGH
CONCAVE
Fig.
4
Alvan-Blanch
Midget
thresher.
60
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
1987
VOL.18
NO.3
FEED
HOPPER
7
" -
Difim
RASP
BAR
TAM,
WALKER
ONCAVE
/
/ /
/
/
/ /
ELECTRIC
MOTO
//
/
(.„.
/
,i/
c
7
Or
RAIN
OUTLET
OSCiLLAT
INO
GREEN
BOX
p
.
.i
fr
ALL
BROKEN
A
A
VI
Eo
REI
RN
tARTE
RIAt,
Fig.
5
LCT
thresher.
energy
meter;
operating
the
thresher
at
no
load
for
15
min
and
then
on
the
load
using
a
50-kg
sample
each
time.
The
gran
straw
ratio
was
de-
termined
by
selecting
three
samples
of
crop
from
the
material
to
be
threshed.
Each
sample
weighed
about
5
kg.
The
weights
of
the
grain
and
straw
were
determined
sepa-
rately
for
each
sample
and
their
ratio
was
calculated.
Results
and
Discussion
straw
walker
and
oscillating
clean-
ing
sieve.
A
15
kW
petrol
engine
was
used
to
operate
the
thresher
for
cleaning
operation.
Experimental
Technique
The
threshing
tests
were
per-
formed
according
to
a
standard
method
suggested
by
IRRI
(Test
Procedure
T-1,
Issue
No.1
May
25,
1978)
and
the
Indian
Standard
In-
stitute
test
code
for
stationary
threshers
for
wheat
(IS
6284,
1975).
The
thresher
performance
was
measured
in
terms
of
grain
out-
put
per
hour,
threshing
efficiency,
broken
grain
percentage
(external
and
internal
damage),
separation
losses,
quantity
of
blown
grain
alone
with
the
straw,
cleaning
ef-
ficiency
and
power
requirements.
The
threshing
effectiveness
was
measured
against
peripheral
speed
of
the
cylinder,
cylinder-concave
clearance,
crop
variation
in
terms
of
moisture
content
and
maturity
and
feeding
rate.
The
optimum
con-
ditions
for
thresher
evaluation
was
set
for
threshing
efficiency
and
cleaning
efficiency
being
95%,
separation
losses
not
exceeding
2%
and
the
seeds
with
glumes
not
exceeding
5%.
The
grain
contain-
ing
glumes
after
having
passed
through
the
thresher
was
con-
sidered
unthreshed.
Three
samples
of
10
kg
each
of
sorghum
earheads
from
each
crop
were
threshed
by
a
particular
thresher.
Threshing
time,
amount
of
grain
collected
at
the
grain
out-
let
and
the
amount
of
grain
in
the
straw
were
measured
for
calculat-
ing
threshed
grain
output
per
hour
and
the
blown
grain
losses.
Three
samples
from
each
outlet
were
drawn
for
analysis
to
calculate
the
threshing
efficiency,
per
cent
glumes,
per
cent
brokens,
cleaning
efficiency
and
moisture
content
at
the
time
of
threshing.
The
grain
moisture
was
determined
by
a
Burrow's
moisture
digital
com-
puter.
Some
of
these
measurements
like
cleaning
efficiency
could
not
be
done
with
the
Alvan
Blanch
thresher
since
it
has
no
cleaning
mechanism.
The
energy
consumed
during
threshing
was
measured
by
an
IRRI
axial-flow
(portable)
IRRI
Axial-flow
Alvan
Blanch
Midget
LCT
IRRI
axial-flow
(portable)
IRRI
Axial-flow
Alvan
Blanch
midget
LCT
Grain
moisture:
10
to
12%.
Comparative
Performance
of
Threshers
Threshers
with
multicrop
poten-
tial,
relatively
low
labour
require-
ments
and
probabilities
of
low
accidents
were
evaluated
for
their
comparative
threshing
performance,
under
optimum
operating
condi-
tions
and
is
given
in
Table
3.
The
axial-flow
paddy
thresher
with
cleaning
attachment
developed
by
IRRI
for
paddy
threshing
was
selected
for
modifications
and
evaluation.
Performance
of
Axial-Flow
Thresher
The
axial
flow
thresher
with
cleaning
attachment
was
evaluated
in
four
steps.
Separa-
tion
loss
Clean-
ing
effi-
ciency
Grain
output
(kg/ha)
Energy
required
kWh/t
Sorghum
(CSH
6)
5.0
4.6
92
96
210
740
73
1000
16
10
30
15
Millet
(BJ
104)
12.1
176
18
3.5
86
480
16
8.1
80
30
63
600
20
Thresher
Threshing
efficiency
Brokens
82
0.3
89
0.7
82
0.4
98
5.5
76
0.2
80
0.6
62
0.2
80
2.0
Table
3
Performance
of
Four
Different
Threshers
for
Threshing
Sorghum
and
Millet
under
Optimum
Operating
Conditions
VOL.18
NO.3
1987
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
61
1.
Initial
attempts
to
thresh
paddy,
sorghum,
millet,
chickpea
and
pigeonpea
without
any
modifica-
tions
in
the
thresher
(open
cylinder
with
pegs
as
original
machine
re-
ceived
from
IRRI).
2.
Modifications
in
the
thresher
components
for
threshing
sorghum
crops.
3.
Threshing
several
crops
with
the
modified
thresher
to
evaluate
the
threshing
performance
of
this
thresher.
4.
Field
testing
of
modified
thresher
in
the
farmers'
field
to
thresh
sorghum
and
wheat.
Performance
of
original
axial-flow
thresher
The
axial
flow
thresher
as
originally
designed
performed
satis-
factorily
on
IR-36
paddy.
The
average
threshed
grain
capacity
was
about
1
000
kg/ha
with
only
1.5%
blown
grains
during
a
continuous
test
period
of
6
h.
Practically
all
the
grains
were
stripped
from
the
panicle
of
the
paddy
stem.
The
cleaning
efficiency
was
about
99%.
The
performance
of
this
thresher
for
sorghum
and
millets
was
very
poor.
The
threshing
efficiency
was
about
36
%
for
sorghum
(CSH-6)
with
cylinder peripheral
speed
of
78
m/min.
The
threshing
efficiency
for
millet
(BJ-104)
was
also
very
low
being
about
36%
with
grain
output
of
about
250
kg/ha
at
the
same
cylinder
speed.
The
performance
of
the
axial
flow
thresher
was
satisfactory
in
comparison
to
the
other
threshers
under
evaluation
for
chickpea
and
stripped
pigeonpea
pods
at
a
mois-
Moisture
Speed
Threshing
content
rpm
component
(m/min)
Chickpea
9
400(628)
Pegs
13
400(628)
Pegs
Pigeonpea
8.4
360(565)
Pegs
8.4
380(597)
Pegs
8.4
400(628)
Pegs
ture
content
of
about
10%.
The
threshing
performance
for
chickpea
and
pigeonpea
is
shown
in
Table
4.
Effect
of
Thresher's
Modifications
The
axial
flow
thresher
with
cleaning
attachment
was
modified
and
evaluated
for
threshing
millet
and
sorghum.
The
thresher
per-
formance
was
improved
by
making
several
changes
on
the
threshing
cylinder
concave
assembly
and
cleaning
sieves
shown
in
Figs.
6
and
7.
The
effects
of
these
modifica-
tions
on
the
sorghum
threshing
performance
is
given
in
Table
5.
An
arrangement
of
4
rows
of
canvas
flaps
(first
2/3
of
cylinder
length)
and
4
rows
of
canvas
flaps
(first
1/3
of
cylinder
length)
with
bar
concave
and
wire
mesh
back
sup-
port
gave
the
highest
threshing
efficiency
(88%),
but
separation
loss
was
quite
high
(25%).
While
us-
ing
8
rows
of
canvas
flaps
(1/3
of
Whole
plant
Whole
plant
Whole
plant
Stripped
material
Whole
plant
cylinder
length)
with
the
above
concave,
the
separation
losses
de-
creased
to
5%
without
any
change
in
threshing
efficiency.
The
grain
output
for
this
arrangement
was
780
kg
of
threshed
grain
per
h.
It
is
evident
from
the
above
results
that
most
of
the
threshing
occurs
in
the
initial
one-third
of
the
cylinder
length.
The
threshing
efficiency
and
output
for
pearl
millet
with
the
modified
thresher
were
80%
and
480
kg/h.
The
amount
of
blown
grains
(separation
losses)
was
about
3.5%
which
was
higher
than
the
tolerance
limit
of
2.0%.
The
energy
required
for
threshing
was
16
kg-h/t.
The
resulting
brokens
were
0.6%.
The
modified
axial
flow
thresher
(4
rows
of
flaps
in
first
2/3
length
and
rest
pegs),
for
sorghum
thresh-
ing
gave
a
higher
percentage
of
blown
grains
(25%).
The
length
of
these
canvas
flaps
were
reduced
to
Table
4
Performance
of
IRRI
Axial-Flow
Thresher
on
Chickpea
and
Pigeonpea
Feeding
method
Threshing
performance
(%)
Grain
output
kg/h
TE
G
B
C
98
2
6
94
500
95
5
5
92
300
93
7
5
90
320
92
8
4
89
380
92
8
8
81
340
*
Diameter
of
the
threshing
cylinder
with
peg
teeth
50
cm;
TE=Threshing
efficien-
cy;
G=Broken
grains;
B=Blown
grains;
C=Cleaning.
CONVAS
FLAPS
MADE
FROM
FLAT
BELT
950
305
350
255
PEGS
STRAW
THRESHING
PADDLES
Ira
T.
a
.420
Fig.
6
Threshing
cylinder.
Fig.
7
Modified
cleaning
sieve.
-
1F
-41."
22
TO
25
62
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
1987
VOL.18
NO.3
1)
Bar
concave
designed
for
paddy
threshing
at
IRRI.
2)
The
original
concave
was
provided
with
rubber
strips
on
the
upper
wide
along
its
length
to
increase
the
crop
retention
time.
Perforated
sheets
with
6
mm
dia
holes
for
1/3
length
and
8
mm
dia
holes
for
the
next
1/3
length
were
bolted
to
the
back
of
the
concave.
Crop:
Sorghum
(CSH-6).
Cylinder
peripheral
speed:
780
m/min.
Table
6
Results
of
a
Modified
Axial-Flow
Thresher
with
Cleaning
Attachment
Based
on
Long
Term
Threshing
Crop
Moisture
content
(%)
Threshing
efficiency
(%)
Cleaning
efficiency
(%)
Blown
grains
(%)
Grain
output
(kg/h)
Paddy
(IR-8)
Sorghum
(Rainy
season
CHS-6)
(Post
rainy
season
CHS-8)
Millet
(B.1-104)
Pigeonpea
(ICP-2)
Chickpea
(Local)
Wheat
(Mexican)
Safflower
13.0
9.6
12.0
13.0
9.0
12.0
99
90
95
80
98
98
97
95
98
92
90
86
79
86
90
6
2
5
4
S
5
1
1
000
740
700
400
300
400
300
1/3
length
and
additional
length
pegs
(13
mm
long
instead
of
9.5
mm
original
length)
were
used
in
the
separation
zone
of
the
cylinder-
concave
assembly
to
minimize
this
loss
and
the
rate
of
blown
grains
was
reduced
to
5%.
The
performance
of
the
modi-
fied
axial
flow
thresher
was
not
suitable
for
pigeonpea
threshing.
The
performance
for
pigeonpea
threshing
was
better
with
pegs
on
the
threshing
cylinder
and
with
the
original
concave
using
stripped
material
as
well
as
whole
plants.
The
cylinder
peripheral
speed
of
about
600
rpm
(380
rpm)
was
satisfactory
for
minimum
broken
grains.
However,
the
cleaning
of
the
threshed
material
at
this
cylinder
speed
was
very
poor
due
to
inade-
quate
flow
of
the
material
on
the
sieves.
Increasing
the
blower
speed
from
700
to
900
rpm,
improved
cleaning.
The
broken
grains
during
threshing
were
less
than
2%.
The
threshed
grain
output
at
this
speed
was
about
400
kg/h.
Performance
for
a
wide
range
of
crops
The
performance
of
suitably
modified
axial
flow
thresher
is
given
in
Table
6
for
a
wide
range
of
crops
threshed
at
ICRISAT
centre
and
under
village
evaluation
(sorghum,
wheat
and
safflower).
The
thresher
performed
satisfactori-
ly
giving
threshing
efficiencies
a-
bove
95%
for
most
of
the
crops
evaluated
during
one
pass
of
thresh-
ing
except
rainy
season
sorghum
and
millet.
The
thresher
per-
formance
for
these
crops
can
be
enhanced
by
further
modifications
in
cylinder-concave
arrangement
to
obtain
less
grains
with
glumes.
The
cleaning
efficiency
for
the
pigeonpea,
chickpea
and
millet
crops
was
very
poor
(less
than
90%)
which
was
due
to
the
lower
oscil-
lation
speed
of
the
sieves
than
the
desired
speed
for
an
adequate
material
flow.
While
threshing
mil-
4
row
of
flaps
(last
2/3
length)
+
pegs
4
row
of
flaps
(first
2/3
length)+4
rows
flaps
(first
1/2
length)
4
row
of
flaps
(first
2/3
length)+
pegs
4
rows
of
flaps
(first
1/3
length)
+
pegs
8
rows
of
flaps
(first
1/3
length)
+
pegs
let,
the
lower
sieve
was
not
of
the
correct
size.
The
ratio
of
blown
grain
ranged
between
1
to
6%
depending
on
the
crop.
The
blown
grains
were
minimum
in
case
of
paddy
and
wheat
(less
than
2%)
while
for
other
crops
these
ranged
from
4
to
6%.
The
threshed
grain
output
ranged
between
300
to
1
000
kg/h
depending
on
the
crop.
The
grain
output
was
maximum
for
paddy
(1
000
kg/h)
while
it
was
minimum
82
25.0
600
88
25.0
640
87
25.0
625
80
5.0
725
87
5.0
780
for
wheat
and
pigeonpea
(300
kg/h).
The
optimum
operating
conditions
based
on
long
term
threshing
are
given
in
Table
7.
Testing
of
Modified
Axial-Flow
Thresher
in
Villages
After
appropriate
modifications
and
intensive
testing
at
ICRISAT
Centre,
the
modified
axial
flow
thresher
(Fig.
8)
was
evaluated
in
villages
primarily
to
note
the
farmers'
response.
This
thresher
was
Table
5
Axial-Flow
Thresher
Modifications
and
their
Effect
on
Sorghum
Threshing
Threshing
Separation
Threshing
Cylinder
Concave
efficiency
loss
capacity
(%)
(%)
(kg/h)
Pegs
full
length
Original
1)
36
2.5
430
4
row
of
flaps
(last
2/3
length)
Original
48
4.8
520
+
pegs
Original
with
perforated
sheet
(6
mm
dia
hole
for
1/3
length)
Modified
2)
Modified
Modified
Modified
VOL.18
NO.3
1987
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
63
Crop
and
variety
Paddy
(IR-Z)
Sorghum
(CSH-6)
Millet
(BJ-104)
Optimum
moisture
content
range
(%)
13-20
10-12
10-12
Threshing
cylinder
configuration
Pegs
Convas
flaps
(first
1/3
+
pegs)
Convas
flaps
(first
1/3+pegs)
Concave
configu-
ration
Welded
m.s.
rod
Modified
(wiremesh
in
first
2/3)
Modified
(siremesh
in
first
2/3)
Cylinder
Cylinder
speed
concave
range
clearance
rpm
(mm)
705-780
12
780-860
6
780-860
Sieve
Speed
size
of
I
II
sieves
(mm)
(Osc/min)
8
6
340
800
6
4
340
800
2
360
Fan
speed
(rpm)
750
Table
8
Performance
of
Axial-Flow
Thresher
for
Sorghum
under
Village
Conditions
Performance
elements
(%)
ICRISAT
hybrids
Maladandi
C
S
H-8
GG-1483
GG-1485
Non-
irrigated
Irrigated
With
concave
Without
concave
sieve
Moisture
content
9.3
9.2
9.8
9.6
9.2
9.8
Threshing
efficiency
Pass
I
98 98
90
95
95
92
Pass
II
94
98
99
98
Grain
with
glumes
2
2
6
2
1
2
Broken
grains
9.0
2.0
1.0
Cleaning
efficiency
96
96
90
96
95
93
Grain
output
(kg/h)
720 730
600
630 650 650
Village:
Shirapur,
Maharashtra,
India.
Test
period:
Feb.
27
to
March
3,
1981.
Sample
size:
Bulk
threshing
Table
9
Performance
of
Axial-Flow
Thresher
for
Wheat
under
Village
Conditions
Performance
element
(%)
U.P.
301
U.P.
310
Moisture
content
12.3
13.4
13.0
Threshing
efficiency
97
92
96
Grains
with
glumes
3
8
4
Broken
grains
0.4
1.2
1.4
Cleaning
efficiency
97
92
96
Grain
output(kg/h)
320
280
270
Village:
Ranjole,
Andhra
Pradesh,
India.
Test
Period:
March
6
and
7,
1981.
Sample
size:
Bulk
threshing
Table
7
Optimum
Operating
Conditions
for
Threshing
a
Wide
Range
of
Crops
Pigeonpea
(ICP-2)
Chickpea
(local)
9-12
Pegs
As
for
paddy
9-11
Convas
flaps
Modified
with
straw
(wire
mesh
choppers
in
the
corn-
in
the
thresh-
plete
concave)
ing
zone.
Extra
thick
pegs
630
780-940
900
800
4.
400
4
340
Thresher:
Axial
flow
thresher
evaluated
for
sorghum
and
wheat.
The
thresher
was
very
much
pre-
ferred
over
existing
local
threshers
by
farmers
due
to
its
low
labour
requirement
and
ease
in
feeding
earheads
along
with
its
better
performance
for
sorghum
threshing
than
the
existing
beater
type
local
threshers
in
villages.
The
thresher
was
operated
for
about
3
days
under
different
operating
condi-
tions
in
a
conventional
village
of
India.
The
four
different
varieties
of
sorghum
threshed
were;
two
ICRISAT
hybrids
(GG-1483)
and
(GG-1485),
a
very
common
local
variety
Maladandi
(irrigated
and
non-irrigated)
and
a
hybrid
released
by
the
Indian
Government
(CSH-8).
After
minor
adjustments,
the
same
thresher
was
evaluated
with
wheat
in
another
village.
The
thresher
was
tested
with
Mexican,
Fig.
8
Performance
evaluation
of
modi-
fied
thresher
on
sorghum.
U.P.301
and
U.P.310
varieties
of
wheat.
Performance
of
Thresher
for
Sorghum
and
Wheat
Threshing
The
thresher
gave
98%
threshed
grains
in
one
pass
with
an
output
of
about
700
kg/h
for
ICRISAT
hy-
brid
sorghum.
With
Maladandi
and
CSH-8
varieties,
the
threshing
ef-
ficiency
and
threshed
grain
output,
were
about
95%
and
600
kg/h
during
one
pass
of
threshing.
CSH-8
was
difficult
to
thresh,
as
the
grain
tended
to
separate
from
the
earheads
in
grain
clusters
instead
of
clean
grains.
The
remaining
5%
of
the
grains
were
removed
during
a
second
pass
of
residuals.
The
moisture
content
of
these
sorghum
varieties
ranged
between
9-10%.
About
2
100
kg
of
grain
were
threshed
in
3.5
h
of
threshing
operation
with
5
family
labours
arranged
to
operate
the
thresher.
64
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
1987
VOL.18
NO.3
About
5
/
of
petrol
was
consumed
during
this
period.
Threshing
efficiency
and
output
for
wheat
was
97%
and
300
kg/h
at
grain
moisture
content
of
12
to
13%.
The
ratio
of
broken
grains
in
the
threshed
material
were
about
1%
with
a
cleaning
efficiency
of
about
95%
(Tables
8
and
9).
Conclusion
The
original
axial-flow
thresher
with
cleaning
attachments
per-
formed
satisfactorily
on
paddy
but
failed
on
most
other
crops
like
sorghum,
pearl
millet,
pigeonpea,
chickpea
and
wheat.
The
thresher
was
modified
to
a
considerable
extent
and
it
had
become
possible
to
thresh
most
of
these
crops
with
minor
adjustments
in
threshing
cylinder-concave
and
cleaning
me-
chanism.
On
the
basis
of
per-
formance
at
ICRISAT
centre
in
India
and
farmers'
fields,
the
modified
thresher
performed
satis-
factorily.
The
results
indicate
that
this
thresher
could
be
operated
as
a
multicrop
thresher,
a
wide
range
of
crops
with
minor
modifi-
cations.
In
village
evaluations,
the
thresher
was
preferred
over
conven-
tional
threshers
due
to
some
ad-
ditional
merits
which
are
its
low
labour
requirements,
ease
in
feeding
earheads,
less
vibrations
during
operation
and
operational
safety.
REFERENCES
Agricultural
Engineering
Today.
July-August,
1980.
Indian
So-
ciety
of
Agricultural
Engineer-
ing,
New
Delhi.
Araullo,
E.V.,
et
al,
1976.
Rice,
Post-harvest
Technology,
IDRC-
530.
International
Development
and
Research
Centre,
Ottawa,
Canada,
PP
370-374.
Bainer,
Roy.
et
al,
1960.
Principles
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Farm
Machinery.
John
Wiley
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423.
Joshi,
H.C.
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K.N.
Singh,
1980.
Axial
flow
thresher
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multi-
crop
potential,
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News
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Feb.-March
1978.
Pathak,
B.S.
et
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1978.
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bruising
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multicrop
threshers
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rasp
bar
type.
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presented
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XVI
Annual
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Kharagpur,
W.B.
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December,
1978.
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K.N.
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H.C.
1979.
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April,
1979
PP
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New
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1978.
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May
25,
1978.
Verma,
S.R.
et
al,
1978.
Design
aspects
of
feeding
system
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power
threshers.
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at
XVI
annual
convention
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I.I.T.,
Kharagpur,
W.B.,
India,
December
18-20,
1978.
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S.M.,
et
al,
1978.
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probability
estimates
for
selected
locations
of
semi-arid
India.
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FSRP,
ICRISAT,
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Walker,
T.S.
and
Khirsagar,
K.G.
1981.
The
village
level
impact
of
machine
threshing
and
impli-
cations
for
techno'ogy
develop-
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in
SAT,
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Economics
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ICRISAT,
Patancheru,
P.O.
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the
Semi-
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1980.
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■■
VOL.18
NO.3
1987
AGRICULTURAL
MECHANIZATION
IN
ASIA,
AFRICA
AND
LATIN
AMERICA
65