Modification of SG-2000 Multi-Crop Thresher
Modification of SG-2000 multi- crop thresher ____________________________________ 2
1, Abstract _________________________________________________________________ 2
2, Introduction _____________________________________________________________ 2
4, Power requirment_________________________________________________________ 4
4.1, Power required for threshing ________________________________________________ 4
4.3, Power required to drive the screw conveyor (N3 _________________________________ 5
5, Power transmission and part determination ____________________________________ 5
5.1, Determine belt size _________________________________________________________ 5
5.2, Determine pully size ________________________________________________________ 7
5.3, Determine drum shaft ______________________________________________________ 9
5.4, Determine pulley Hub______________________________________________________ 11
5.5, Determine diameter and length of the drum. (D) _______________________________ 12
5.6, Concave arc length (Lc), ___________________________________________________ 12
5.7, Selection of bearing ________________________________________________________ 12
5.8, Keys ____________________________________________________________________ 13
5.9, Determine auger and blower belt ____________________________________________ 15
5.10, DESIGN OF SIEVE______________________________________________________ 16
5.11, Desigewn of air channel (blower ____________________________________________ 17
6, Fabrication of multi- crop thresher__________________________________________ 19
6.1, Techanical specification ____________________________________________________ 19
6.2, Material selection _________________________________________________________ 20
7,Testing of modified SG-2000 multi- crop thresher ______________________________ 20
7.1 Testing method ____________________________________________________________ 20
7.2,The formulas used for collecting different parameter ____________________________ 20
7.3, Specification _____________________________________________________________ 22
7.4, Testing multi-crop thresher on wheat and barely _________ Error! Bookmark not defined.
7.5, Result and decision for testing barely and wheat__________ Error! Bookmark not defined.
7.6, Testing of multi-crop thresher on teff ___________________ Error! Bookmark not defined.
7.7, Combination for the best performance for threshing teff ___ Error! Bookmark not defined.
7.8, Testing of multi-crop thresher on sorghum ______________ Error! Bookmark not defined.
7.9, Combination for the best performance for threshing sorghumError!
defined.
Bookmark
not
7.10 Testing of multi- crop thresher on maize ________________ Error! Bookmark not defined.
7.11, Combination for the best performance for threshing maize Error! Bookmark not defined.
1
Modification of SG-2000 Multi-Crop Thresher
Modification and performance evaluation of
SG-2000 multi- crop thresher
1, Abstract
The study of the proposal was to develop affordable multi-crop thresher by
which modifying SG-2000 thresher with 10 hp diesel engine ADN-43 with a
capacity of 2-quintal per hour depending on the type of crop. The thresher
redesigned with cleaning mechanism and evaluated for its performance in terms
of threshing efficiency, cleaning efficiency, visible damage and sieve loss. The
result indicate for optimum performance, and the thresher should operate at
cylinder speed ( 10:900, 10:100,:14:600, 15:450) for wheat barely teff sorghum
maize respectively.
2, Introduction
Indigenous threshing of crops (wheat, barely and sorghum etc,) is
one of the most time consuming labours and maximum loss of grain. After
harvesting the crop transported to the threshing site where they are left stacked
till the threshing season, which is usually December and January. The threshing
floor usually made smearing the ground with caw dung and left to dray for some
time or levelling the ground and trampling according the type of crop which is
going to be threshed.
During threshing the loose crop is laid on the floor and several
oxen tread on it. The oxen go round on the threshing floor over the crop for
some time and are taken out to turn the un threshed crop from the bottom up and
spread it laying the heads up for efficient treading.
Threshing with animals need skill and energy to keep the animals
moving around the threshing floor. Usually the best-trained animals are used as
the pivots on the canter of the ring while other animal’s circle around. The
threshing season normally lasts 2-3 months, but with the increased in
production, which is possible with the high yielding varieties, nevertheless,
threshing may not be completed with this time. The delay on completion of the
threshing operation within safe time will expose the crop to unfavourable
weather and will result in quality deterioration, insect and rodent attack. Oxen,
which are not in good conduction, are exposed to danger during the threshing
season. Therefore this method of threshing brings low quality of grain and high
percentage of loss.
2
Modification of SG-2000 Multi-Crop Thresher
The existing method does not encourage high output and often result in
low quality products. But there is a growing need to provide the farmers with an
appropriate thresher. To overcome such shortcomings SG 2000 Global- 2000
promoted original multi-crop thresher. The thresher is designed with out
cleaning mechanism only for threshing.
The following demerits are observed during on farm testing and
evaluation SG-2000 the original model.
1. Engine is exposed for fire in working condition.
2. Air cleaner clogged frequently by chaff and straw.
3.Un suited construction of concave sieve for different crop; un threshed
ear and straw were disserved.
4. Construction of grain and straw outlet at one side (direction) caused
mix-up of grain mixture and straw.
5 Un comfort for feeding due to small heights of the thresher feeding
table inlet hole respectively.
6 .Extra length of feeding table at the right side with the edge of the inlet
hole caused breakage of ears.
7. Poor cleaning efficiency, tedious and time, labours consuming for
cleaning, separating straw and grain mixture.
To avoid the demerits the following points were recommended.
1. Safety guard for the belt.
2. Changing the position of grain mixture outlet by using auger.
3. Height of the thresher from the ground should be increased by 15 cm.
4. Length of the feeding table should be equal fit to inlet hole edge at the
right side.
5. Blower and shaking sieve should be designed for cleaning mechanism.
Keeping the merits the SG-2000 multi-crop thresher was under taken
with the following objectives;
 To redesign the machine with shaking sieve and blower.
 To test the performance of the thresher in respect of
threshing efficiency, cleaning efficiency and visible
damage.
 To study and recommend the best combination of
operating parameters such as feed rate cylinder speed and
average power requirement.
3
Modification of SG-2000 Multi-Crop Thresher
3, working principles of modified SG-2000
Threshing
In this model threshing is done by the impact of a cylindrical drum
equipped with a number of spikes mounted on its periphery. The crop is brushed
into fine straw, which results in good animal feed. But, on other hand, this adds
to the problem of cleaning.
Separating
While being threshed, the material undergoes a spiral motion in a
closed cylindrical casing the lower part of which is meshed bars. Meanwhile,
the grain with the fine straw is dropped to the sieve and straw is delivered to the
outlet through which it is discharged. The spiral motion is affected by the
special arrangement of curves on the inner side of the cover.
Cleaning
The grain and fine straw that escaped through the concave are exposed
to the blower blast. At this stage the light particles are blown to the atmosphere
while the grain goes to a collecting pan through the oscillating sieve. The grain
is then conveyed by means of an auger to a point where it is finally collected.
4, Power requirement
4.1, Power required for threshing
N1 =mv2 + Aw1 + Bw3
1-f
Where m = total mass of material feed to the drum kg/s
=Mass of the grain + mass of straw
(Approximate grain straw ratio = 1:1.5 in mass)
For wheat m = 500 kg/h +1.5(500) kg/h =0.35kg/s
V = tip speed of the drum (m/s) 28m/s
F = friction coefficient (0.7…0.8)
Aw1= factor accountable to the resistance of bearings. (0.3x10-2 kgfm)
Bw3 =factor accountable to air resistance (0.48x10-2 kgfm)
W = angular speed of the drum (rad/s)
(900 r.p.m =94 red/s)
N1 = 0.35x282/1-0.75 +0.3x102 x94 +0.48x102x843= 5.08kw
4.2,. Power required for driving the blower (N2)
N2=cp/gxWn3D5
Where cp=power coefficient (1.7 for straight steel plate blades)
W=weight density of air
W=air g
=1.2kg/m3x9.81m/s2
=11.8N/m3
4
Modification of SG-2000 Multi-Crop Thresher
N=blower angular speed (1500r.p.m =157rad/s)
D=blower diameter (200=0.2)
g=acceleration due to gravity (9.81m/s2)
N2= 1.7/9.81x11.8x1573x0.195
=1.959kw
4.3, Power required to drive the screw conveyor (N3)
N3=QL/367(wα+sinβ) 1/ή (kw)
Where Q=conveyor capacity (ton/h)
L=conveyor length (m) =0.8m
W=material factor. (4 for non –abrasive dry material)
 =Inclination angle (00)
η = drive transmission efficiency (90%)
But Q=15πD2snΨρC
Where D=outside diameter of the screw (m), 0.85m
S=screw pitch (m)
N =screw speed (r.p.m.) 1310 r.p.m
Ψ=loading efficiency (0.4 for free flow non –abrasive material)
C=factor for inclination from horizontal (β=0, C=1)
ρ=bulk density of material (ton/m3),
ρwheat =0.75ton/m3
Q=15π(0.085) 2 x0.057x1310x0.4x0.75x1=6.68ton/h
Therefore N3=6.68x0.8/367x(4+sin00)x1/0.9
= 0.06kw
Total power required (Nt)
Nt=N1+N2+N3
=5.08+1.96+0.06
=7.1kw
Considering transmission loss and the power required for the reciprocating
motion of the sieve 8kw engine is recommended.
5, Power transmission and part determination
5.1, Determine belt size
type of drive
motor speed
drum shaft speed
Engine power
v-belt
3000r.p.m.
1000r.p.m.
8kw
1, Design power,
P=NxS
Where s = service factor
5
Modification of SG-2000 Multi-Crop Thresher
Then P= 7.1x1.1=7.81 kw
2, Speed ratio,
VR= n1/n2 = 3000/1000= 3
3, Torque on the engine shaft,
T1=1000xP/w1
T1=1000x8/377=21.2Nm
4. The design diameter of the smaller sheave (engine pulley),
d1= CT 1/3= 40x21 1/3=110.3 mm
Let d1=100 mm, belt type “B”, size bb=14, h=10.5, A=138mm2
5, Compute the larger sheave diameter (driven pulley),
d2=d1xVRx (1-s)
d2=100x3x0.98=294 mm
let d2=300mm
6,Determine the belt speed.
V=w1d1/2x1000=377x100/2x1000=18.8 m/s
= 19m/s
7,Find the angular speed of the drum shaft.
W2=d1xw1x (1-ε)/d2=100x377x(1-0.02)/300=123 rad/s
8,Compute the actual speed ratio.
VR=w1/w2=377/123=3
9,Determin the tangential force (transmitted load)
Ft=2T1x1000/d1 =2x21x1000/100=420N
10,Optimum centre distance,
A =1.5xd2/VR 1/3 =1.5x300/31/3 =312 mm
Maximum centre distance, amax=2(d1+d2)=2(100+300)=800 mm, since it is
governed by the drive layout the centre distance will be convenient. So a=430
mm
11, Determine the belt length.
L=2a+1+2/a
1=(d1+d2)/2 =3.14(100+300)/2 =628
2=(d2-d1 /2)2= [(300-100)/2]2
=10000
L= 2x430+628+10000/430 =1511.2 mm, lets round to the nearest standard
value L=1600mm type= B68
12, Refine the centre distance.
a = 0.25[(L-1)+((L-1) 2-82)1/2]
=0.25[(1600-628)+((1600-628) 2-8x10000) 1/2]
=475.5mm
13, Compute the angle of contact.
=180-60(d2-d1)/a
6
Modification of SG-2000 Multi-Crop Thresher
=180-60(300-100)/430
=1520
14, Determine the rate of belt run.
R=1000V/L
=1000x19/1600
=11.87 s-1
15, Determine the initial and effective stress.
Where Ka=effect of speed ratio, 1.14
C=effect of the angle of contact on traction, 0.92
Cs=service factor, 0.8
Ko=5.55/R 0.09-6bb 1.57/(d1ku)-10-3 v2
=5.55/10.6 0.09-6x14 1.57/(100x1.14)-10 –3192=0.92 Mpa
16, Allowable effective stress.
[K]=KoCCs=0.92x1x0.8=0.73 Mpa
17, Find the required number of belts. (Z’)
Z’=Ft/([K] A1)=420/0.73x138=3.9 take Z=2
18,Find the maximum belt tension.
Design power, =(F1-F2) V/1000 kw,
e
and F1/F2=e where e=/sin/2, =co-efficient of friction of
on the pulley surface =0.3,=380
e=0.3/0.325=0.922 ,
There fore, F1/F2=e 0.922*2.6 =e 2.4 =11
11F2=F1
F1-F2
=420
N,
F2
=42,
F1=420+F2=420+42=462N
5.2, Determine pully size
1, determines the torque
on the drum shaft.
VR= T2/T1
T2=VRxT1x
Where VR=velocity ratio
= efficiency of belt drive (0.94)
T2=3x0.94x21= 59.22
2 calculate the design diameter of the driving pulley on the drum shaft.
d3 = C (T2)1/3
=40(59)1/3
=155mm let d3=140mm
3. Calculate the design diameter of the blower pulley.
d4 =(d3xd1/n4xd2)n1 =(140x100/1500x300)3000 =88.9
let d4 = 90mm
4. Calculate the design diameter of the auger pulley.
7
belt
then
Modification of SG-2000 Multi-Crop Thresher
d4 =(d3xd1/n4’xd2) n1 = (140x100/1310x315)3000 = 101.8mm
Let d4’=140mm or d4 = 255mm
5. Determine the belt speed.
V =w3d3/2x1000
w2=w3=117rad/s
=123x140/2x1000 =8.6m/s
6. Calculates the angular speed of the blower shaft.
w4 =d3xw3(1-)/d4
=140x123x0.98/90
=187.5rad/s
7. Blower shaft velocity ratio.
VR=d2xd4/d1xd3 =300x90/100x140=1.9
8 calculate the angular speed of the auger shaft.
w4’=d3xw3(1-)/d4’
=140x123x0.98/140
=120.5 rad/s
9. Auger shaft velocity ratios.
VR=d2xd4/d1xd3 =300x140/100x140 =3
10 calculate optimum and maximum center distance of ventilator shaft.
aop =1.5dl/(VR)1/3
=1.5x40/(2)1/3
=166.7mm
amax=2(d3+d4)=2(140+90)=460mm
11 calculate optimum and maximum center distance of auger shaft.
aop =1.5dl/(VR)1/3=1.5x40/(3)1/3=142.5mm
amax =2(d3+d4’) = 2(140+255) =780 mm
To arrived at the diameter of the shaft determine:
A, Maximum twisting moment acting on the shaft.
B, Maximum bending moment acting on the shaft.
 Find the load acting on the shaft due to the belt tension and due
to loads and due to the weight of the pulleys.
 The force of belt tension and weight of the pulleys and drum
bend the shaft vertical plan.
Given data, effective tension in the belt on the tight and slack sides,
F1=462N, F2=42N
 Weight of the drum Gd = 431N
 Weight of the pulley Gp = 59N
 V-belt tension
Fb = 504N
Impulse force – the peripheral force which appears when the plant mass is
brought into motion may be obtained.
8
Modification of SG-2000 Multi-Crop Thresher
F=m’v/1-f
Where m’=mass flow rate
V=peripheral speed
f = friction coefficient (0.7--0.8)
m’=q0xlxm
Where qp=permissible feed rate (0.17-0.2kg/s.m)
l=length of the beater (0.8m)
m=number of beaters,
m’=0.2x0.8x9=1.44kg/s,
F=1.44x28/1-0.8=202N
5.3, Determine drum shaft
563
633
section 2-2
section 1-1
section 3-3
400
400
112
Rb
Ra
Graph no-1
Calculate the reaction force at the support.
MA=0
MB=0
Y=0
633x0.4-RBx0.8+563x0.92
RB = 633x0.4+563x0.92/0.8 =964
RAx0.8-633x0.4+551x0.12
RA=633x0.4-563x0.12/0.8
RA=232
232-633+964-563=0
Bending moment diagram.
First portion
Mt=234x, when
x=0.2M1=46.8
x=0.4M1=93.6
Second portion
M2=RAx0.4-633 (x-0.4)
X=0.4
M2= 232x0.4-633(0.4-0.4)=93.6
9
x=0
M1=0,
Modification of SG-2000 Multi-Crop Thresher
X=0.6
M2= 232x0.6-633(0.6-0.4)=13.8
X=0.8
M2=232x0.8-633(0.8-0.4)=-67.6
Third portion
M3=232x-633(x-0.4)+964(x-0.8)
X=0.8
M3=232x0.92-633(0.92-0.4)+964(0.92-0.8)=-67.6
X=0.92
M3=232x0.92-633(0.92-0.4)+964(0.92-0.8)=0
Determine the twisting moment.
T= 1000xP/ =1000x7/102 =69Nm
Equivalent twisting moment.(Te) =(Mb2+T2)1/2
Where Mb =bending moment
T=twisting moment
2
2 1/2
Te=(94 +69 ) 117Nm
Determine the diameter of the shaft.(d)
Fs=0.75xdesign stress for commercial shaft
fs=shear stress
563
633
Rb
Ra
400
120
400
vertical load diagram
92.8
vertical moment diagram
-67.6
torsional moment diagram
69
Graph no 2
Fs=0.75x56Mpa=42N/mm2
Therefore 117=/16xd3x42x106
d3 =117x16/x42x106 =0.024m
10
Modification of SG-2000 Multi-Crop Thresher
Let shaft diameter d=30mm
5.4, Determine pulley Hub
a, diameter
d1- outer diameter of hub = 2x30=60mm
b, length of the hub
L =1.5d to 2d= 1.5x30= 45mm
To check the hub
T/J = fsi /r1
r1 =Hub radius
J = Polar moment of inertia
= /32(d14-d4)
d1 = Hub diameter
fs1 = Induced shear stress
__T___
= fs1
4 4
/32(d1 -d )
d/2
1504 =
fs1
4 4
/32(6 -3 )
6/2
fs1 =37.8kg/cm2
This is less than the permissible shear stress (about 50-60kg/cm2) in C.I.
hub. Hence hub is safe.
To find arms dimensions
N = Number of arms, 4
a = Major axis of elliptical section
b = Minor axis of elliptical section
a = 2b(say)
M = Bending moment on each arm
= T/n1
Where
n1 = n/2 = 4/2 = 2
M = 1504/2 =752 kg cm
f = Permissible stress in arms = 160 kg/cm2
Z = Modules of section of ellipse
752 = fx/64 xa3
M = fxz
752 = 160x/64 xa3
a =4.57 cm
b = a/2 = 4.57/2 = 2.3 cm
Rim thickness
T = D/300+3mm = 300/300 +3 mm = 4 mm
11
Modification of SG-2000 Multi-Crop Thresher
5.5, Determine diameter and length of the drum. (D)
The drum diameter is determined by the type of crop to be
threshed by selecting the appropriate peripheral speed v at mid point of the
teeth. Then the path traversed by the teeth mounted in the same traverse plane
during one revolution of the drum would equal to the length of the drum
circumference, that is:
D = Vtm
D =Vtm/
Where t=time between beating. (0.005_0.008) s
V= peripheral speed (m/s)
m=number of plates on the drum
D=28x0.006x9/3.14=0.48m
Drum length (Lm),
(L)=m’/m0 n
Where m’=mass flow rate,
m0=mass flow rate per unite length of drum (kg/s) (0.17_0.2)
n=number of beaters on the drum
L=1.44/0.2x9=0.8m
5.6, Concave arc length (Lc),
Loc=(/360)D=145/360x3.14x0.48=0.6m
5.7, Selection of bearing
1,Determine the radial forces imposed on the bearing.
Radial load =drive load+static load (weight)
Fr=(Ntx19.1x106xKd/Pdxn)+Wd
Where Nt=power to be transmitted.
Kd=drive tension factor (1.5 for v-belt).
Pd=pitch diameter of the pulley.
n=r.p.m of the drum.
Wd=static load of drum.
Fr= (7x19.1x106x1.5/300x1000)+4.4=764N
The equivalent forces imposed on the bearing.
Peq=(XFr+Yfa)
Where P=equivalent load.
Fa=thrust on axial load. (Neglected)
Y=thrust factor, Y=0
X=radial factor. X=1
V=rotation factor.
V=1 for all type of bearing of inner race
12
Modification of SG-2000 Multi-Crop Thresher
is rotating
Peq=1x1x764=764N
The equation does not account for any shock or impact forces
and temperature conduction which a bearing may expanse incorporating these
two factor.
The design load ( F) is calculated from equivalent loads F’.
F=PxKaxKt
Where Ka=application factor or service factor, 1.5
Kt=temperature factor. 1.1
F=796x1.1x1.5=1261N
Required radial load rating (Cr).
Cr=FxKexKs,
where Ke=life factor. Ks=special factor.
Ke=(Ld/Le)1/5= (24000/10000)1/5=1.2
Ld=desire life bearing. hrs
Le=catalogue life of bearing. hrs
Ks=special factor.
nd =rotational speed of bearing. r.p.m
ne=catalogue rotational speed. r.p.m
1/5
1/5
Ks=(nd/ne) =(1000/500) =1.15
Cr=FxKexKs=1261x1.2x1.15=1740
Desired life for the bearing will be.
L= a yearxb (months/yea) x c (days/month) x d (hours/day)
=10x300x8 =24000, (assuming 300 days per year)
The bearing type is selected from the table based on d and Cr. No-6205
5.8, Keys
A key is used to prevent relative motion between shafts and member to
whom it is connected hub. To accommodate the key, a groove called key way is
cut both on shaft and hub. After assembly key is partly in the shaft and partly in
the hub, Key have been standardised and are generally proportioned to the shaft
diameter.
L=length of key
1.5d to 3d =2.5x30 =75mm
w=width of key
d/4
30/4= 7.5mm, 8mm
t=thickness of key
d/8
30/8= 3.75mm , 4mm
d=diameter of shaft
13
Modification of SG-2000 Multi-Crop Thresher
Drawing no-1
The strength of the key for failure by shearing is.
p=wxlxfs  fs = 2T/dwl <[fs] where fs= shear stress,
p= power T/d/2=2T/d
[fs]= 120N/mm2 allowable shear
stress for steel with fixed of joint.
Fs=2x69x103 =7.6 N/mm2
30x8x75
2
fs<[fs] 7.6 < 120N/mm
allowable shear stress
The strength of the key for failure by crushing is.
P=lxt/2xfc  fc =2T/dx2/lxt= 4T/dxlxt
Where fc=crushing stress, then fc< [fc] allowable crushing stress
[fc]=150N/mm2
fc= 4x69x103
30x75x4
=30.6N/mm2 <150Nmm2
14
Modification of SG-2000 Multi-Crop Thresher
Ø140
63
4,
9
47°
78°
749,69
auger and blower drive
R45
Ø2
50
56°
6
8,2
55
Drawing no--2
5.9, Determine auger and blower belt
The design length of the is: L=aicosi+0.5diI
The angle I between the centerlines and the component branches
are found for each pair of pulleys using the following formula.
= Arcsine [(dl-ds)]
2a
The contact angles are given by: =1800-i+/-i+/-i-1
Where  is the angel made by the central lines of the i th pair of pulleys.
The plus signs are used if motion is transmitted from a larger to smaller pulleys
and the minus sign, when motion is transmitted from smaller to a larger pulley.
1=arcsine [(d2-d1)] =arcsine [(140-90)]=2.3
2a1
2x623
2 =arcsine [(d3-d2)] =arcsine [(250-140)]=4.14
2xa2
2x764
3 =arcsine [(d3-d1)] =arcsine [(250-90)] =8.14
2xa3
2x565
Contact angle
1= 1800-800+2.3-8.14=94.160=1.64 rad
15
Modification of SG-2000 Multi-Crop Thresher
2=1800-400+2.3-4.14=138.160=2.4 rad
3= 1800 -600-8.14-4.14=107.70=1.9 rad
L=ai cosI +0.5dii
L=623cos2.30+762
cos
4.140
+565cos8.140
+0.590x1.64+140x2.4+250x1.9 = 2421 mm,
Let L round to the nearest standard value 2438 mm
5.10, DESIGN OF SIEVE
Round holes whose principal dimension is the diameter d are punched
so that their center lie on the vertices and canter’s of the regular hexagon and
such that two parallel sides of the hexagon lie perpendicular to the direction of
the motion of the grain. The relationship between the interval b between two
adjacent holes and the hole diameter is an empirical one given by b = 0.9d
Belt length:
Drawing no--3
SELECTION OF THE SIEVE
The vibration of the screen is responsible for the performance of the
following functions.
1, it helps in providing passage to particles through the opening of the screen.
2, it restricts clogging of the screen by particles that become trapped in the
opening.
3, because of vibration the particles are stratified over the screen surface and
each particle have to meet the screen opening.
4, continuous flow of particles along the screen is possible.
Particle and foreign matter whose dimension is greater than the largest
dimension of a grain of the principal crop.
Lmax  d(B)  L”max
16
Modification of SG-2000 Multi-Crop Thresher
The slop of the sieve is governed by the condition that the grain mass must
not slide over it. When the sieve is stationary that is, the angle of slop  must be
less than the friction angle  of the grains over the sieve.
<
The principle parameters to be determined in design sieves are
separation effectiveness, working dimensions of the opening, the over all size of
the sieve (length, width).
The separation effectiveness  is the ratio off the mass of particles
p passing through the sieve to the mass of impurities accompany the feed, that
is:
 = p/(CQ)
Where c is the coefficient of separation which defines the quantity of
impurities in the feed.
Q is the feed rate of the grain mix, that is, the sieve capacity, separation
effectiveness  is considered high for  =0.8 medium for
 = 0.65 and low for  = 0.5, when seed material is to be obtained, the value of
 should be 0.8.
The working dimensions of the openings in the sieve are based on the
size of the grains in the incoming grain-mix and the specification imposed on
the material being processed.
While deterring the width of the sieve we must consider two factors-the greater the width of the sieve, the higher is cleaning capacity. However, if
the width of the sieve is increased, its cleaning device begins to bulge or the
fabric sags. Hence in grain cleaning machines the width of the sieve is usually
limited to 1m and stiffeners are usually provided to prevent sagging or bu
5.11, Design of air channel (blower
Drawing no--4
17
Modification of SG-2000 Multi-Crop Thresher
1. The feed rate of the contaminants, which are to be entrained by the air
stream, is obtained as
q1 =bq/100
Where q1= feed rate of the grain stock.
b = the amount of contaminants (%) in the feed
material.
q1=0.35x150/100 =0525 kg/s
2.An air stream velocity u is selected such that it is greater than the terminal
velocity of the light contaminants and smaller than that of the principal grain
material.
For wheat terminal velocity ut = 8.9------11.5m/s
3.The quantity of air required to entrain the material is determined from the
expression.
0=q1/q2
Where 0 <1 is the concentration coefficient of the contaminant- air
mix,
q2 is the air delivery per unit time, kg/s.
q2 =q1/0
0.525/0.6 =0.875 kg/s
Then q2 = q1/0, the air delivery (m3/s), V is then obtained as V=q2/,
where  is the density of air. ( =1.43 kg/m3)
V = 0.875/1.43 = 0.61m3/s
4.The cross-sectional area of flow of the channel is then obtained as
F = V/u, m2
0.62/9 0.069m2
5.The dimensions of the channel is rectangular with sides a and b, then
specifying one of the sides the other can be obtained from the expression;
the length of the channel is equal to the length of the sieve
b= 0.8m
Then axb = 0.069m2
a =0.086m2
18
Modification of SG-2000 Multi-Crop Thresher
6, Fabrication of multi- crop thresher
Drawing no--5
6.1, Techanical specification
 Over all size
LxWxH
146x156x126
 Drum type spike tooth
 Drum diameter
0.48m
 Drum length
0.8m
 Concave arc length
0.6m
 Drum speed
800-1000r.p.m
 Fun speed
1500r.p.m
 Number of blade
4
 Drum concave clearance inlet
20 cm
 Drum concave clearance outlet
4 cm
 Auger speed
1310 r.p.m
 Power source
8 kw diesel engine
Feeding method
manual
19
Modification of SG-2000 Multi-Crop Thresher
6.2, Material selection
The drum of the thresher is spike mounted on the periphery of 0.8m
lengths and 0.48m diameters. It is used with open type concave
covering 1520 of cylinder circumference fabricated from flat iron
30x6 and round bar 8mm with a clearance of 5mm between metal
rods. The feeding hopper fabricated from mild steel of 1.5mm thick
wich is located perpendicular to the horizontal cylinder axis. A
blower consisting of adjustable opening and four fan blades mounted
on a shaft with 29cm diameter, and supported by a sailed ball
bearing. The separator section consists of sieve with 7mm hole
diameter, which is replaceable according to the type of seeds. Under
the sieve the auger and the grain pan is located. The sieve is driven
by eccentric wheel.
7, testing of modified SG-2000 multi- crop
thresher
7.1 Testing method
A combination of feed rate (F) three level 6kg, 8kg, 10kg cylinder
speed (S) at three level (800, 900 1000) rpm. The opening of blower
(amount of air needed for cleaning) will be optimum. Wheat, barely
bundle were feed in to threshing unites and threshed materials was
collected at the outlet which was cleaned and weighed. The portion
of the material contain un threshed grain was separated from straw
and weighed after hand threshing and cleaning in order to determine
the threshing efficiency interims of percentage of the total grain
recovered.
7.2, The formulas used for collecting different parameters
i. Moisture content
From the material, which is to be threshed, 3 samples are
randomly taken of approximately 0.5 kg each. The samples are
placed in sailed plastic containers and taken to the laboratory
where the grains and straw are separated by hand. The straw
and grains from each sample are kept paired. After weighing,
the samples are oven dried at 1300 c for at least 15 hours and
then reweighed. The moisture content on dry loss, %
Moisture content of the grain is a major factor in
controlling grain damage. Decrease in moisture content greatly
increases the brittleness of grain.
M = 100 x weight of the wet sample – weight of dry sample
Weight of dry sample
20
Modification of SG-2000 Multi-Crop Thresher
The mean value is taken as representative of the test sample.
ii. Grain straw ratio
After determining the weight of dry samples from number of
the result of the paired samples are used to calculate the main
grain /straw ratio.
The grain straw ratio,
K = weight of the dry grain
Weight of the dry straw
iii. Threshing efficiency (%)
= 100- Quantity of unthreshed grain in samplex100
Total grain in sample
iv. Cleaning efficiency – Clean grain received at grain outlet
with respect to the total grain mixture received at main grain
outlet expressed as a percentage by mass.
Cleaning efficiency (%) = W-w
W
v.
Visible damage (%) =
= Quantity of broken of broken grain in sample (g)x100
Total grain input per unit time
vi. Sieve loss (%) =
Free, clean grains collected from sieve sample per unit time
Total grain input per unit time
General
1.
2.
Location of the test
1.
Test No
two
1.1
Region
Amhara
1.2
Zone
North Shewa
1.3
Woreda
Deneba
1.4
Village (service cooperation)_ Woreda Gebirena
1.5
Name of the place
Wolle
1.6
Owner ship
Woreda Gebirena
Test Experts
1. Worku B.
2. Mulugeta A.
21
Modification of SG-2000 Multi-Crop Thresher
3.
Name of contact farmer participated in the test
4.
5.
Production year
1995—1996(E C
Duration of the test starting date
17/6/96
Ending date
18/6/96
6.
Climatic conduction
Dega
7.
Average rainfall
8.
Average temperature
9.
Elevation above sea level
10. Slope
11. Topography
flat
7.3, Specification
1 .Name of manufacturers
KARC
2. Type of sample (prototype)
3 .Type of threshing
direct threshing
3.1. Type of drum
spike (peg) type
a. Shape
cylindrical
b. Sized
d =0.48m, l=0.8m
c. Material
flat iron 30x6, round bar 12
3.2. Type of concave
meshed bar
a. Shape
Semi-oval
b. Size
l= 680 cm,
c. Material
round bar 8 mm, flat iron 25x8
3.3. Type of cleaning mechanism
inclined blower
a. Shape
circular
b. Size
680 mm
c. Material
sheet metal = 1.5 mm
d. Type of feeding mechanism
manual
3.4.1. Feeding table
a. Shape
flat
b. Size
900 mm x610 mm
c. Material
sheet metal = 1.5 mm
3.4.2. Inlet hole (hopper)
a. Shape
rectangular
b. Size
170 mm x135 mm
c. Material
sheet metal
4. Source of power
Diesel engine AND 47
a. Type of drive
V- belt drive
b. R.P.M of the engine max
360 rpm
c. Average power consumption for one hour
22
Modification of SG-2000 Multi-Crop Thresher
d. Fuel consumption
C, Operation time
1lt/h
15:40 hr
7.4, Testing multi-crop thresher on wheat and barely
. Table 1
No
Treatme
Time
1 10, 800, --- 1min
2 10,900, ---
1min
3 10,1000,--
1min
4 9,800,--
1min
5 9,900,--
1min
6 9,1000,--
1min
7 8,800,--
1min
8 8,900,--
1min
9 8,1000,-
1min
Testing of multi -crop thresher on wheat
Sample from Clean gr Un-th gr
main outlet
3kg
siev overflow 670g
chaff outlet
6g
main outlet
2.8kg
siev overflow 834g
chaff outlet
6.6g
main outlet
2.785kg
siev overflow 695g
chaff outlet
4.5g
main outlet
2.815kg
siev overflow 694g
chaff outlet
12g
main outlet
2.585kg
siev overflow 355g
chaff outlet
7.7g
main outlet
2.385g
siev overflow 423g
chaff outlet
6g
main outlet
2kg
siev overflow 205g
chaff outlet
12g
main outlet
2kg
siev overflow 176g
chaff outlet
8.2g
main outlet
2kg
siev overflow 270g
chaff outlet
5g
23
Brokn
3g
7.8g
6g
4.5g
7.7g
12g
4g
8g
9.7g
straw
272g
4kg
1.95kg
245g
4kg
1.5kg
241g
4kg
895g
195g
2.695kg
1.595kg
389g
2.695kg
1.295kg
304g
2.1kg
1.95kg
303g
2kg
1.7kg
400g
2.2kg
1kg
350g
1.785kg
1.685g
Modification of SG-2000 Multi-Crop Thresher
Table 2
No
1
2
3
4
5
6
7
8
9
Performance data of multi-crop thresher at different combination of feed rate cylindeer speed for wheat
wheat
Treatment
Threshing efficiency cleaning efficiencyVisible damege Normal gr
Sieve loss
F1,S1,C1
91.5
0.1
99.9
18.2
F1,S2,C1
91.9
0.21
99.6
22.8
F1,S3,C1
92
0.16
99.8
24
F2,S1,C1
93.5
0.13
99.8
19.7
F2,S2,C1
85.6
0.26
99.7
12
F2,S3,C1
85.7
0.42
99.5
14.9
F3,S1,C1
85.6
0.16
99.6
9.2
F3,S2,C1
83.3
0.35
99.64
8
F3,S3,C1
85
0.42
99.6
11.8
treat ment
T1
T2
T3
feed 1
feed 2
91.5
93
92
89
86.9
88.7
feed 3
83
83.3
85
Graph -1
cleaning efficiency
effect of speed and feed rate on cleaning
efficiency
95
90
10kg/min
9kg/min
8kg/min1
85
80
75
T1
T2
T3
speed
Graph 1 show that cleaning efficiency increases as the feed rate and drum speed
increase up to certain limit and then decrease.
24
Modification of SG-2000 Multi-Crop Thresher
Treatment feed 1
feed 2
feed 3
T1
0.1
0.13
0.18
T2
0.21
0.26
0.35
T3
0.3
0.42
0.43
Effect of speed and feed rate on
visible damage
visible damage
Graph 2
0.5
0.4
10kg/min
9kg/min
8kg/min
0.3
0.2
0.1
0
T1
T2
speed
T3
Graph 2 shoes that with increase in speed, the visible damage increase
Treatment feed 1
feed 2
feed 3
T1
18.2
11
9.2
T2
22.6
12
8
T3
24
14.9
11.8
Effect of speed and feed rate on sieve
loss
Graph 3
30
sieve loss
25
20
10kg/min
9kg/min
8kg/min
15
10
5
0
T1
T2
speed
25
T3
Modification of SG-2000 Multi-Crop Thresher
Graph 3 shows that increase the feed rate and drum speed increases the sieve
loss. It is because at a higher feed rate the volume of the material handled by the
sieve is more than enough. So that the material flow out from the sieve..
The best combination for maximum threshing efficiency cleaning
efficiency with minimum damage and sieve loss for wheat was obtained at feed
rate of 8 kg/min and 900 r.p.m
Table 3
No
1
Treatme
10, 800, ---
2
10,900, ---
3
10,1000,--
4
8,800,--
5
8,900,--
6
8,1000,--
7
6,800,--
8
6,900,--
9
9
6,1000,6,1000,--
Testing of multi -crop thresher on barely
Time Sample from
Clean gr Un-th gr
1min main outlet
2.795 kg 15 g
siev overflow
73 g
chaff outlet
5g
1min main outlet
2.794 kg 34 g
siev overflow
196 g
chaff outlet
5g
1min main outlet
2.394 kg 27 g
siev overflow
240 g
chaff outlet
2g
1min main outlet
2.194 kg 31 g
siev overflow
36 g
chaff outlet
3g
1min main outlet
2 kg
14 g
siev overflow
98 g
chaff outlet
1g
1min main outlet
2 kg
12 g
siev overflow
166 g
chaff outlet
2g
1min main outlet
1.594 kg 20 g
siev overflow
27 g
chaff outlet
3g
1min main outlet
1.594 kg 13 g
siev overflow
58 g
chaff outlet
27 g
1min main outlet
1.394 kg 27 g
siev overflow
213 g
chaff outlet
2g
26
Brokn
straw
655 g
2.95 kg
1.29 kg
428 g
3.95 kg
1.95 kg
514 g
3.49 kg
1.95 kg
787 g
3.69 kg
248 g
583 g
4.95 kg
210 g
474 g
3.95 kg
1.69 kg
551 g
2.39 kg
295 g
385 g
2.95 kg
1.95 kg
455 g
1.49 kg
1 kg
Modification of SG-2000 Multi-Crop Thresher
Table -4
Treatment feed 1
feeed 2
feed 3
T1
99.4
98.6
98.5
T2
99.8
99.3
99.24
T3
99.9
99.5
98.8
Effect of speed and feed rate on
threshiong efficiency
Graph 4
100.5
100
treshing
efficiency
No
1
2
3
4
5
6
7
8
9
Performance data of multi-crop thresher at different combination of feed rate cylinder speed for
barely
Threshing
cleaning
Normal
Sieve
Treatment
efficiency
efficiency
Visible damage
grain
loss
F1,S1,C1
99.4
81
2.5
F1,S2,C1
98.6
85.8
6.5
F1,S3,C1
98.5
82.5
9.1
F2,S1,C1
98.6
75
1.6
F2,S2,C1
99.3
77.5
4.6
F2,S3,C1
99.5
80.9
7.6
F3,S1,C1
98.6
74.5
1.6
F3,S2,C1
99.2
80.5
3.2
F3,S3,C1
98.3
75.6
13
10kg/min
9kg/min
8kg/min
99.5
99
98.5
98
97.5
T1
T2
speed
T3
Graph 4 shows that threshing efficiency increases as drum speed increase for all
feed rate. This is because at a higher speed the energy imparted to the ear head
and grain increases causing higher threshing efficiency..
27
Modification of SG-2000 Multi-Crop Thresher
Treatment feed -1
feed -2
feed -3
T1
81
75
74.5
T2
85.8
82
80.6
T3
82.5
80.9
75.6
Graph 5
Effect of speed and feed rate on
cleaning efficiency
cleaning
efficiency
90
85
10kg/min
9 kg/min
8kg/min
80
75
70
65
T1
speed
T2
T3
Graph 5 shows that cleaning efficiency increases as feed rate and drum speed
increase increases up to a certain limit and decrease again. This is because of the
density of the threshing material is less the chaff will pass through the concave,
due to this cleaning device begin to bulge.
Treatment feed 1
feed 2
feed 3
T1
2.5
1.6
1.5
T2
6.5
4.6
3.2
T3
9.1
7.6
7
Graph 6
sieve over flow
10
Effect of speed and feed rate on sieve over
flow
8
10kg/min1
9kg/min
8kg/min
6
4
2
0
T1
T2
speed
28
T3
Modification of SG-2000 Multi-Crop Thresher
Graph 6 shows that as the feed rate and speed increase the sieve loss increase.
This is because of at a higher feed rate the volume of the material handled by
the sieve is more than enough.
There for the best combination for maximum threshing efficiency cleaning
efficiency (80%) and minimum visible damage (0.2%) and sieve loss was
obtained at a feed rate 9 kg/min and 900 r.p.m. The maximum out put (capacity)
is 200 kg/hr.
Test No-3
Region
North Wollo
Name of the place
Mersa
Owner ship
Mersa Agricultural Training centre
Production year
1996-----1997 EC
7.6, Testing of multi-crop thresher on teff
Table 5
No
1
Treatme
8, 800, ---
2
8,900, ---
3
8,1000,--
4
10,800,--
5
10,900,--
6
10,1000,--
7
12,800,--
8
12,900,--
9
12,1000,-
Testing of multi -crop thresher on teff
Clean
Time Sample from
gr(kg)
Un-th gr
1min main outlet
1.585
siev overflow
0.825
chaff outlet
0.003
1min main outlet
1.08
siev overflow
1.169
chaff outlet
0.003
1min main outlet
0.955
siev overflow
1.357
chaff outlet
0.0055
1min main outlet
2
siev overflow
1.4
chaff outlet
0.01
1min main outlet
1.8
siev overflow
1.2
chaff outlet
0.001
1min main outlet
1.215
siev overflow
2
chaff outlet
0.0162
1min main outlet
2.387
siev overflow
1.157
chaff outlet
0.007
1min main outlet
1.587
siev overflow
2
chaff outlet
0.005
1min main outlet
1.387
siev overflow
2.387
chaff outlet
0.013
29
Brokn
Straw(kg)
0.274
0.003
2
0.099
2.5
0.003
0.11
3.6
1.8
0.28
3.3
3.1
0.155
3.5
2.1
0.052
3.9
2.6
0.212
5.1
2.5
0.138
4.5
2.5
0.076
3.7
3.3
Modification of SG-2000 Multi-Crop Thresher
Table—6
Treatment feed 1
feed 2
feed 3
T1
85
87.7
91.9
T2
89.9
92
92
T3
91.6
95
95.2
Effect of speed and feed rate on
cleaning efficieny
100
grraph 7
95
cleaning
efficiency
No
1
2
3
4
5
6
7
8
9
Performance data of multi-crop thresher at different combination of feed rate cylinder speed for
teff
Threshing
cleaning
Visible
Normal
Sieve
Treatment
efficiency
efficiency
damage
grain
loss
F1,S1,C1 (8,800,-- }
85
84
F1,S2,C1(8,900, -- )
89.9
23.6
F1,S3,C1 (8, 1000,--)
91.5
51.9
F2,S1,C1 (10,800,--)
87.7
55
F2,S2,C1 (10,900,--)
92.4
41
F2,S3,C1 (10, 1000,--)
95
39.9
F3,S1,C1 (12, 800,--)
91.9
62
F3,S2,C1 (12, 900,--)
92
32.5
F3,S3,C1 (12, 1000,--)
94.6
55.
90
feed 1
feed 2
feed 3
85
80
75
T1
T2
speed
T3
Graph- 7 shows that cleaning efficiency increases as the feed rate and drum
speed increases up to the optimum point.
30
Modification of SG-2000 Multi-Crop Thresher
Treatment feed 1
feed 2
feed 3
T1
84
62
60
T2
73
41
32
T3
51.9
40
39
Effect of speed and feed rate on sieve
loss
100
sieve loss
80
8kg/min
10kg/min
12kg/min
60
40
20
0
T1
T2
speed
T3
Graph- 8 shows that as the speed and feed rate decrease sieve over flow increase
Combination for the best performance for threshing teff
• The best combination for maximum threshing efficiency and cleaning
efficiency Sieve loss was obtained at feed rate of 10 kg 1000 r.p.m in this
conduction the maximum output (capacity) is 194 kg/h
7.8, testing of multi- crop thresher on sorghum
Test No—4
Table -7
No
1
Treatment
10, 600, ---
2
10,700, ---
3
10,800,--
4
12,600,--
5
12,700,--
Testing of multi -crop thresher on
Clean
Time Sample from
gr(kg)
1min main outlet
6.16
siev overflow
0.84
chaff outlet
1min main outlet
0.006
siev overflow
1.587
chaff outlet
0.12
1min main outlet
5.587
siev overflow
1.5
chaff outlet
1min main outlet
7.784
siev overflow
0.987
chaff outlet
0.196
1min main outlet
7.387
siev overflow
1.387
31
sorghum
Un-th
grain
0.023
0.032
0.126
0.02
0.032
0.007
0.015
0.096
0.097
0.1
0.007
0.017
0.066
Broken
0.006
0.002
0.021
0.012
0.023
0.031
0.076
0.043
0.06
0.013
0.003
0.024
0.023
0.005
Straw(kg)
0.183
0.612
1.5
0.132
0.7
1.3
0.2
0.9
1.3
0.092
0.7
1.7
0.079
0.7
Modification of SG-2000 Multi-Crop Thresher
6
12,800,--
1min
7
14,600,--
1min
8
9
14,700,--
14,800,-
1min
1min
chaff outlet
main outlet
siev overflow
chaff outlet
main outlet
siev overflow
chaff outlet
main outlet
siev overflow
chaff outlet
main outlet
siev overflow
chaff outlet
0.163
7.587
1.387
0.106
9.187
1.387
0.037
8.787
1.587
0.146
8
2.387
0.132
0.01
0.005
0.048
0.008
0.141
0.013
0.0086
0.007
0.07
0.045
0.037
0.065
0.027
0.092
0.003
0.02
0.046
0.005
0.006
0.017
0.015
0.01
0.019
1.5
0.092
0.7
1.5
0.587
1.3
1
0.175
1
2
0.16
1.3
1.5
Table—8
No
1
2
3
4
5
6
7
8
9
Performance data of multi-crop thresher at different combination of feed rate cylinder speed for
sorghum
Threshing
cleaning
Visible
Normal
Sieve
Treatment
efficiency
efficiency
damage
grain
loss
F1,S1,C1 (10,600,-- }
97
97
0.4
99.4
12
F1,S2,C1(10,700, -- )
98
97.8
0.84
99.16
20.9
F1,S3,C1 (10, 800,--)
98
96.6
2.42
97.58
20.9
F2,S1,C1 (12,600,--)
97.7
98.8
0.43
99.57
11.8
F2,S2,C1 (12,700,--)
98.9
98.9
0.71
99.29
16
F2,S3,C1 (12, 800,--)
99
98.8
1.97
98.03
15.67
F3,S1,C1 (14, 600,--)
98
94
0
100
14.2
F3,S2,C1 (14, 700,--)
99
97.9
0.26
99.74
15
F3,S3,C1 (14, 800,--)
99
98
0.41
99.59
23
32
Modification of SG-2000 Multi-Crop Thresher
Treatment feed 1
feed 2
feed 3
T1
97
97.7
98
T2
98
98.9
99
T3
98.5
99
99
threshing
efficiency
Effect of speed and feed rate on
threshing efficiency
100
99
98
97
96
95
10kg/min
12kg/min1
14kg/min
T1
T2
speed
T3
Graph 9 shows threshing efficiency increases with the increase in cylinder speed
for all feed rate.
Treatment feeed 1
feed 2
feed 3
T1
97
96
94
T2
98
97.9
97.5
T3
98.5
98
97.9
Graph 10
cleaning efficiency
Effect of speed and feed rate on cleaning
efficiency
99
98
97
96
95
94
93
92
91
10kg/min
12kg/min
14kg/min
T1
T2
speed
T3
Graph 10 shows that cleaning efficiency increases as the feed rate decrease and
speed increase.
33
Modification of SG-2000 Multi-Crop Thresher
Treatment feed 1
feed 2
feed 3
T1
0.4
0.43
0
T2
0.84
0.74
0.26
T3
2.42
1.97
0.5
Graph 11
Effecty of speed and feed rate on visible
damage
3
visible damage
2.5
2
10kg/min
12kg/min
14kg/min
1.5
1
0.5
0
speed
T2
T1
T3
Graph 11 shows that as the drum speed increase the visible damage increase for
all feed rate.
Treatment feed 1
feed 2
feed 3
T1
12
13
14.2
T2
15
18
21
T3
19
20
23
Effect of speed and feed rate on sieve
overflow
Graph 12
sieve over flow
25
20
10kg/min
12kg/min
14kg/min
15
10
5
0
speed
T2
T1
T3
Graph 12 shows that as the speed and feed rate increase the sieve over flow
increase.
34
Modification of SG-2000 Multi-Crop Thresher
7.9, Combination for the best performance for threshing sorghum
The best combination for maximum threshing efficiency cleaning efficiency
94% with maximum visible damage and sieve loss 14% was obtained at feed
rate of 14 kg/min, cylinder speed 600 r.p.m. In this case the maximum output
(capacity) is 636kg/hr
7.10, testing of multi- crop thresher on maize
Test No—5
Table -9
No
1
Treatment
15, 350,---
2
15,400,--
3
15, 450,--
4
20,350,---
5
20,400,--
6
20,450,---
Testing of multi -crop thresher on Maize
Clean
Un-th
Time Sample from
gr(kg)
grain
1min main outlet
7.3
siev overflow
0.867
1.987
chaff outlet
1.6
1.987
1min main outlet
8.3
siev overflow
1.187
chaff outlet
1.6
0.007
1min main outlet
8
siev overflow
1.587
chaff outlet
2
0.587
1min main outlet
5
siev overflow
1.187
chaff outlet
3
1min main outlet
8.587
2
siev overflow
1.587
chaff outlet
2
1min main outlet
10.187
siev overflow
2
chaff outlet
2.587
0.987
Broken
0.156
0.004
117
0.008
Cob(kg)
0.0065
0.007
2.7
0.033
1.7
0.093
0.009
0.007
0.16
0.008
0.175
0.016
3
0.4
4.1
0.024
0.016
0.127
0.021
Table—10
No
1
2
3
4
5
6
Performance data of multi-crop thresher at different combination of feed rate cylinder speed for
maize
Threshing
cleaning
Visible
Normal
Sieve
Treatment
efficiency
efficiency
damage
grain
loss
F1,S1,C1 (15,350)
83
99.9
0.5
99.5
7.4
F1,S2,C1(15, 400)
94
99.6
1
99
10
F1,S3,C1 (15, 450)
95.2
100
0.9
99.1
12.9
F2,S1,C1 (20,350)
85.9
99.5
1
99
7.7
F2,S2,C1 (20,400-)
86
99.7
1.3
98.7
11
F2,S3,C1 (20,450--)
93.7
99.8
0.93
99.01
12.7
35
Modification of SG-2000 Multi-Crop Thresher
treatment feed 1
feed 2
T1
83
85.9
T2
94
95
T3
95.2
96
Graph 13
Effect of speed and feed rate on
shelling effeciency
100
shelling
efficiency
95
15kg/min
20 kg/min
90
85
80
75
T1
T2
cylindeer speed
T3
Graph 13 shows shelling efficiency increases as the speed increase
treatment feed 1
feed 2
T1
99.6
99.5
T2
99.9
99.7
T3
100
99.8
Graph 14
Effect of speed and feed rate on
cleaning efficiency
cleaning
efficiency
100.2
100
15 kg/min
20 kg/min
99.8
99.6
99.4
99.2
T1
T2
speed
T3
Graph 14 shows that as the feed rate increase the cleaning efficiency decrease.
36
Modification of SG-2000 Multi-Crop Thresher
treatment
T1
T2
T3
feed 1
feed 2
0.5
1
1
1
1.3
1.3
visible damage
Graph 15
effect of speed and feed rate on
visible damage
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0.5 1r 1
feed
feed rate 2
T1
T2
speed
T3
Graph 15 shows as the speed and feed rate increase the visible damage increase.
T1
T2
T3
Graph 16
7.4
10
12.9
7.7
11
12.7
Effect of speed and feed rate on
sieve overflow
sieve
overflow
15
feed 1
feed 2
10
5
0
speed
T2
T1
T3
Graph 16 shows the relation between drum speed and sieve loss. As the
speed increase the sieve loss increases.
7.11, Combination for the best performance threshing maize
The best combination for maximum threshing efficiency 95% cleaning 98%
with minimum visible damage 0.9% and sieve loss 12.9% was obtained at feed
rate of 15 kg/min cylinder speed 400 rpm.
7.12, Conclusion
37
Modification of SG-2000 Multi-Crop Thresher
38
Modification of SG-2000 Multi-Crop Thresher
Prepared by Worku Biweta
Mulugeta Agenhu
Nuru Mohamed
Tadele Tafesse
Kombolcha 1996
39