Misr J. Ag. Eng., 23(2): 324-345 FARM MACHINERY AND POWER … · 2010-06-20 · Misr J. Ag. Eng., April 2006 326 and concave clearance. These variables are also related to the threshing

Misr J. Ag. Eng., April 2006

324

MODIFICATION OF THE THRESHING DRUM OF A STATIONARY THRESHER TO SUIT SEPARATING

FLAX CROP

Zakaria M. I. Emara1

ABSTRACT

The aim of the present investigation is to modify the threshing drum of a local stationary thresher (at a private workshop) to suit separation of flax seeds with minimizing the stalks damage. An automatic device for determining the separating times and giving signal after separating the seeds has been designed and fabricated at a private workshop, Kafr El-Sheikh Governorate. The thresher was evaluated and tested at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate under four feed rates of 8.57, 12.86, 17.14 and 21.43 kg/min. and four drum speeds of 24.25, 25.81, 27.33 and 28.85 m/s, two threshing drums of 8 and 12 fingers arranged in five sets each and three separating times of 10, 15 and 20 seconds. Machine productivity (seed output), seeds losses, stalks damage and energy requirements had been determined. The developed thresher productivity, seed and stalk damage, threshing efficiency and energy required for separating flax seeds had been positively affected by both of feed rate, drum speed, number of drum fingers and separating time. On the other hand, the unthreshed seed were positively and negatively affected by the feed rate and drum speed respectively, for the other different treatments. The drum fingers of 12 and separating time of 15 seconds of the developed stationary threshing machine gave the maximum productivity and threshing efficiency and minimum values of seed, stalk damages, consumed energy and criterion costs compared with the drum fingers of 8 and separating times of 10 and 20 seconds. Results showed that development of the threshing drum tended to improve the performance of the stationary thresher, especially productivity and efficiency in addition to decreasing the seed losses and stalk damage compared with the machine before development. The optimum performance for the developed thresher for separating flax seeds was at drum speed of 28.85 m/s, feed rate of 8.57 kg/min. drum fingers of 12 and separating time of 15 seconds. The maximum threshing efficiency of these conditions was 96.92% but the minimum unthreshed seed losses, seed and stalk damage and energy were 1.33, 3.48, 3.26% and 1.262 kW, respectively.

1 Senior Researcher, Ag. Eng. Res. Inst., Dokki, Giza.

Misr J. Ag. Eng., 23(2): 324-345 FARM MACHINERY AND POWER


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INTRODUCTION

ntil now we do not find threshing and winning machine dealing with flax crop and suitable for small farm. Flax crop requires special treatment tin threshing and keeping stem without damage.

Flax can be grown for fiber, seed or both. In Egypt, the flax cultivated area was about 35700 fed., producing 4.4 ton fibers/fed and 0.74 ton seeds/fed yearly2. Flax is harvested manually by hand pulling. Then lifted for natural drying for about seven days and crop is transported to factories where deseeding (stripping and threshing) is carried out. The disadvantage of this method relies on the great losses in capsules due to handling and transporting.

Gol and Nada (1991) concluded that the important factors affecting the efficiency of the mechanical pod stripping element are speed of operation and condition of crop. Percentage of shelled pods increased by increasing of cylinder peripheral speed which ranged from 0.1 to 3% corresponding to the peripheral speed of 473 to 675 m/min.

El-Behiry et al. (1997) found that the feeding rate increasing linearly by increasing drum speed. Also feeding rate depends on the experience of the thresher labourer. The straw sizes decreased with increasing drum speed, while the grain losses increasing. Also, the straw sizes decreased at lowest moisture content under all threshing machines.

Mohamed (1994) indicated that the relationship between the power consumed and feed rate was an increment proportional, with increasing feed rate, the power increased. He also reported that unthreshed grain losses were significantly affected by application power, where increasing power decreased unthreshed grain losses. The same author noticed that the power consumption during threshing operation was increased by increasing crop moisture content.

Helmy (1988) found that there was a good positive effect of feed rate on unit energy consumption. By increasing the feed rate from 0.06 to 0.31 kg/s the unit energy increased from 0.57 to 1.03 kW.h/Mg and from 0.37 to 0.70 kW.h/Mg for an American threshing machine and from 0.63 to 1.15 kw.h/Mg and from 0.42 to 0.79 kW.h/mg for a local threshing machine at 18.8, 13.5 % and 13.6, 9.7 % grain and straw moisture contents, respectively using cylinder speed 20.52 m/s.

Huynh et al. (1982) stated that the seed separation from the stalks and passage of seed through the concave grate is a function of some variables such as crop feed rate, threshing speed, concave length and cylinder diameter

2 Ministry of Agriculture, 1998.

U


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and concave clearance. These variables are also related to the threshing losses and seed separation efficiency.

Szarszunov (1998) concluded that ineffective threshing and threshing damage are the main causes of flax seed loss. Experiments were carried out to reduce the losses and damage of flax seeds by improving the precision of their separation during threshing. Gummert (1991) showed that the feed rate is significantly affecting power requirement. The function of the investigated range is proximately linear and if feed rate is doubled, power requirements are 2.5 times higher. Badway (2002) reported that the highest threshing efficiency was 97.17% at the optimum performance of deseeding machine. By increasing drum speeds from 9.28 to 15.33 m/s the machine capacity increased from 1800 to 2400 kg/h.

El-Haddad. (2000) stated that the threshing efficiency increased with increasing of drum speed and decreasing of feed rate. The maximum threshing efficiency was 99.761% at drum speed 21.25 m/s (1400 r.p.m), and feed rate 15 kg/min. He added that the maximum amount of visible grain damage was 0.90% at drum speed 21.25 m/s and feed rate of 15 kg/min.

El-Ashry et al. (2003) indicated that the energy requirements was 3.19, 3.4 and 1.6 kW.h/Mg for complete, partial mechanized and conventional systems, respectively. At one Mg of flax, the costs of threshing were 44.44 and 37.76 L.E at complete mechanized system and conventional systems, respectively. It was noticed that the criterion costs were maximum at complete mechanized system because of increasing stalk losses and damage.

The aim of the present investigation was to develop the threshing drum, of a stationary thresher to suit threshing flax seeds and test, evaluate its performance under different operating conditions in addition to design an automatic device to determine the separating time and giving alarm after finishing to draw the crop stalks.

MATERALAL AND METHODS

Field experiments were conducted during winter season of 2002/2003 at Agricultural Research Station, Sakha, Kafr El-Sheikh Governorate. A local stationary thresher, which was manufactured by El-Haddad, 2000, has been developed to suit separation of the flax seeds (Sakha 1) as indicated in Fig. 1. The development included modifying the threshing drum with rubber fingers instead of the metal fingers to decrease damage of flax stalks during separating operation as shown in Fig. 2. On the other hand, number of drum fingers must be suitable for seeds quality on the stalks. The modification local stationary thresher for threshing the flax crop has been evaluated and tested under different operating conditions. The technical specifications and


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operating parameters of the modification threshing machine are indicated in Table 1. Some of physical properties of flax crop are shown in Table 2.


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Table 1: Technical and operational specifications of the thresher.

Items Before modification After modification

Length, cm 90-124 90-124

Width, cm 71 71

Height, cm 129 -145 129 -145

Mass, kg 154 147

Source of power Self operated engine, 5

hp (3.75 kW) Self operated engine, 5

hp (3.75 kW)

Type of the drum Spike tooth Rubber fingers

Length of the drum, cm 24 24

Diameter of the drum, cm 29 29

Drum spiders

No. of teeth 40 40 60

Length, cm 9.5 9 9

Width, cm 1.5 1.5 2.25

Thickness, cm 0.5 1.2 1.2

Control circle Without control Electric automatic

control of separating time

Input opening for crop, cm 30 × 25 30 × 25

Output opening for straw, cm 25 ×12 25 ×12

Output opening for seed, cm 19 ×12 19 ×12

Hole diameter for curved sieve, cm

1.1 1.1

Blower dimensions, cm 30 diameter and 10

wide 30 diameter and 10 wide

The number of the semi circular concave holes

26 per 10 ×10 cm3 26 per 10 ×10 cm3


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Table 2: Physical properties of flax plant Items Average

Stalk diameter, mm 1.798 Technical stem length, cm 82.58 Upper branch zoon length, cm 11.149 Straw yield per plant, g 1.506 No. of capsules per plant 8 No. of seed per plant 60 Mass 1000-seed, g 6.701 Capsule diameter, mm 6.46

Experimental treatments:

Different levels of drum speed, feed rate, drum finger and separating time were used in this investigation and are as follows:

1. Four drum speeds: 24.25, 25.81, 27.33 and 28.85 m/s;

2. Four feed rates 8.57, 12.86, 17.14 and 21.43 kg/min.;

3. Two threshing drums [each of them contains 5 groups each group consists of 8 fingers "total = 40 fingers" of the first drum and 12 fingers "total = 60 fingers" of the second drum]; and

4. Three separating times of 10, 15 and 20 seconds.

Electric circuit for determining the threshing time:

The aim of this circuit was to determine the minimum time required for threshing the seeds from flax stalks through alarm which determines the required time for separation. Consequently maximum threshing efficiency can be obtained in a small time thus, the thresher productivity increases and the operating costs decrease.

The electric circuit comprises the following main units.

1. Power supplying circuit:

The main function of the power supplying circuit is to convert the direct current (DC) to the alternative current (AC) its value 8 Volt and 10 Ampere. This circuit consists of transformer (12V) and bridge to pass the current in one way in addition to integrated circuit (IC 7808) for regulating the current (Volt) and some of capacitors as shown in Fig. 3.


331


332

2. Oscillator:

The main function of the oscillator is to generate pulses, the value of each pulse is 3.45 k Hz. The oscillator consists of integrated circuit (IC 555) and number of transistors and capacitors in addition to two infrared LEDs as shown in Fig. 3.

3. Receiver:

The main function of this receiver is to receive the infrared pulses from the oscillator and compare it with adjusted voltage. If the value of the infrared pulse equals the value of the pulse which is adjusted of the receiver, the output voltage is negative. Otherwise, discorresponding the infrared pulse with the adjusted pulse, the output voltage is positive which is used to operate the relay or the feeding engine as shown in Fig. 3.

This circuit comprises an integrated circuit IC 567, an infrared lamp and number of resistances, condensers and transistors.

Operating method:

1. The transmitting lamp has been put in one sides of threshing unit, while the receiving lamp was put in the opposite side of threshing unit opening.

2. At operating, the output pulse from transmission circuit passes through transmission lamp to the receiving lamp, consequently the output from receiving unit is positive.

3. At threshing, the seeds from the plants, the stalks cut the pulse passed from transmission unit to the receiving unit and the outlet of receiving unit converts to positive, consequently operating the first integrated circuit (555) and its outlet is converted from negative to positive through controlled period by variable resistance (the required threshing time). After finishing from operation of IC 555, the second integrated circuit 555 gives a signal through alarm to draw the crop stalks and the separating time can be adjusted by variable resistance.

Measurements:

During test performance of the developed threshing machine, the following items were measured:

Stalks damage:

Stalks damage were calculated according to the following formula.

1.............................100)/( WstWspsdamageStalks

Where:

Wsps= mass of split portion stalks during threshing, g and


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Wst = total mass of stalks rather than capsules, g.

Unthreshing seeds:

Unthreshed seeds were calculated according to the following formula.

2...........................100)/( tcuc WWseedsgUnthreshin

Where:

Wus= mass of unthreshing seeds, g and

Wts = mass of total seeds, g.

Visible seed damage:

Visible seed damage was determined at different drum speeds, feed rates, drum fingers and separating times for randomized samples 50 g was done by separating the visible damage seeds by hand. Percentage of the damaged seed was determined.

Invisible seed damage:

A germination test was made to determine the invisible seed damage. The samples of this test were taken from a portion of the working sample that remained after separating seed damage. The germination test was carried out in three Petri dishes for each experiment, in each Petri dish 50 seeds were placed on a filter paper, covered with water and incubated at 20 OC for 24 hours. The germinated seeds were counted in each dish and expressed as a percentage of the original number of seeds. The average of three replications was taken as the percentage of the germinated seeds for the experiments.

Threshing efficiency:

The threshing efficiency could be estimated according to Mishra and Desta, 1990 by using the following equation.

3........,%........)/(100 12 WWefficiencyThreshing

Where:

W1= total mass of seed in the sample, g and

W2 = mass of unthreshing seeds in the sample, g.

Consumed power:

Consumed energy was calculated by accurately measuring the decrease in fuel level in fuel cylinder immediately after carrying out each treatment. The following formula was used to determine consumed power (Embaby, 1985).


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4......................,36.1

1

75

1427...

3600

1kWVCLFcE mthfr

Where: FC = Fuel consumption rate, L/h; f = Density of the fuel, kg/L (for solar fuel = 0.85 kg/L);

L. C. V. = Lower calorific value of fuel kcal/kg; (average i.c.v. of solar fuel is 10000 kCal./kg);

427 = Thermo- Mechanical equivalent, kg m /kCal.; th = Thermal efficiency of the engine (considered to be about 35 %

for diesel engine); and

m = Mechanical efficiency of the engine (considered to be about

80% for diesel engine).

All the data collected were subjected to statistical analysis as described by Snedecor and Conchran (1980). Mean values were compared by using Duncan's Multiple range test (1955).

RESULTS AND DISCUSSION

Seed output:

The effect of drum speed, feed rate and separating time on seed output under different number of drum fingers are shown in Fig. 4. The seed output increased as the drum speed increased from 24.25 to 28.85 m/s (1600 to 1900 r.p.m.) for all levels of feed rate, separating time and drum fingers.

At feed rate 8.57 kg/min., increasing drum speed from 24.25 to 28.85 m/s tended to increase the seed output from 1.15 to 1.61 kg/min., while increasing the feed rate from 8.57 to 21.43 kg/min., the seeds output increased from 1.342 to 2.898 kg/min. at drum speed of 25.81 m/s, separating time of 10 seconds and 8 drum fingers. The results also indicated an increase in seeds output with increasing feed rate both of and drum speed at all combination of other variables.

The drum fingers of 12 achieved the maximum values of seeds output compared with the drum fingers of 8 at all feed rates, drum speeds and separating times. The separating times of 10, 15 and 20 seconds gave seeds output of 2.898, 3.070 and 2.800 kg/min., respectively, at drum speed of 25.81 m/s, feed rate of 21.43 kg/min. and drum fingers of 8. Generally, developing the threshing drum increases the seeds output compared with the


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thresher before development for all the tested variables. The increment of seed output reaches 15.6% as a result of developing the threshing drum compared with the thresher before development.

Stalks damage:

Fig. 5 shows the effect of drum speed, feed rate and separating time on stalks damage for tow different numbers of drum fingers. The results indicated that stalks damage increased as the drum speed was increased when other variables were kept constants. At feed rate of 8.57 kg/min. when the drum speed increased from 24.25 to 28.85 m/s, the stalks damage increased from 5.212 to 6.870%. When the feed rate increased at constant variables, the stalks damage decreased for the developed threshing machine. When the feed rate increased from 8.57 to 21.43 kg/min. the stalks damage decreased from 5.212 to 4.215% at drum speed of 24.25 m/s, separating time of 10 seconds and drum fingers of 8.

The numbers o fingers on the threshing drum of 12 and the separating time of 15 seconds gave the lowest values of stalks damage for all the drum speeds and feed rates. The stalks damage increased by 26.9 and 21.41% when the separating time decreased and increased than 15 seconds at feed rate of 12.86 kg/min. drum speed of 25.81 m/s and drum finger of 12. However, developing the threshing drum of the stationary thresher tended to decrease the stalks damage by 13.8% compared to the thresher before modification.

Unthreshed seeds:

The effect of drum speed, feed rate, separating time and drum fingers on unthreshed seeds is shown in Fig. 6. The unthreshed seeds decreased as the drum speed was increased from 24.25 to 28.82 m/s at constant feed rate and constant separating time addition to constant drum fingers. Similar results were obtained by Helmy (1988). The unthreshed seeds decreased by 24.9% when the drum speed increased from 24.25 to 28.85 m/s at feed rate 21.43 kg/min. separating time of 15 seconds and 8 drum fingers, when the feed rate was increased, at constant other variables. The unthreshed seeds increased for developed threshing machine as shown in Fig. 6. Similar results were obtained by Kepner et al.(1982). The unthreshed seeds reached 38.5% when the feed rate has been increased from 8.57 to 21.43% kg/min. at drum speed of 24.25 and separating time of 15 seconds.

At drum speed of 24.25 m/s (1700 r.p.m), when the feed rate was increased from 8.57 to 21.43 kg/min. the unthreshed seed increased by 38.5%. Generally, the unthreshed seed increased with the increase of feed rate and drum speed for all drum fingers and separating times. The unthreshed seeds decreased by 16.5% when the separating times has been increased from 10 to 20 seconds at drum speed of 27.33 m/s and feed rate of 17.17 kg/min. using


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threshing timem, 5

4

8.57 12.86 17.14 21.43

T hreshing t ime, 10 seco nd__8 F ingers - - 12 F ingers

0.5

1

1.5

2

2.5

3

3.5

4

24.25 25.81 27.33 28.85

See

d o

utp

ut,

kg/m

in.


0.5

1

1.5

2

2.5

3

3.5

4

24.25 25.81 27.33 28.85

See

d o

utp

ut,

kg/m

in.


0.5

1

1.5

2

2.5

3

3.5

4

24.25 25.81 27.33 28.85

Drum speed, m/s

See

d o

utp

ut,

kg/m

in.

1

2

3

4

5

6

7

24.25 25.81 27.33 28.85

Sta

lks

dam

age,

%



1

2

3

4

5

6

7

24.25 25.81 27.33 28.85

Sta

lks

dam

age,

%


1

2

3

4

5

6

7

24.25 25.81 27.33 28.85

Drum speed, m/s

Sta

lks

dam

age,

%

Feed rate, kg/min.

Fig. 4: Effect of drum speed, feed rates Fig. 5: Effect of drum speed, feed rates and and threshing time on the seed threshing time on stalks damage under output under different number different number of drum fingers. of drum fingers.


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12 drum fingers. However, the development which was entered on the threshing drum decreased the unthreshed seeds compared with the same thresher before development for all the studied variable.

Visible seed damage:

The effect of drum speed, feed rate and separating time on visible seed damage under two different levels of drum fingers is shown in Fig 7. The results indicated that visible seed damage increased as the drum speed was increased at constant values of the other variables. When drum speed was increased from 24.25 to 28.85 m/s it was found that visible seed damage increased from 0.221 to 0.727% at feed rate 8.57 kg/min., separating time of 10 seconds and 8 drum fingers.

The visible seed damage decreased by 49.5% as a result of increasing the feed rate from 8.57 to 21.43 kg/min. However, the separating time of 15 seconds and number of fingers on the drum of 12 fingers gave the lowest value of visible seed damage compared with the other levels for all the feed rate and drum speeds. The visible seed damage increased by 18.8 and 14.9% when the separating time increased and decreased than 15 seconds, respectively, at drum speed of 27.33 m/s, feed rate of 12.86 kg/min. and drum 12 fingers. On the other hand, the visible seed damage after development was less than before development for all the tested variables.

Invisible seed damage:

Fig. 8 shows the effect of drum speed, feed rate and separating time on invisible seed damage for two numbers of drum fingers. From the obtained results, it can be obviated that the invisible seed damage increased as a result to increase the drum speed when other variables were kept constant. At feed rate of 17.14 kg/min. when drum speed was increased from 24.25 to 28.85 m/s, the invisible seed damage increased from 3.602 to 6.932% at separating time of 10 seconds and 8 drum fingers.

At drum speed of 25.81 m/s (1600 r.p.m), increasing the feed rate from 8.57 to 21.43 kg/min. the invisible seed damage decreased from 5.73 to 2.423% at separating time of 10 seconds and 8 drum fingers. The invisible seed damage decreased by 57.71% when the feed rate was increased.

The invisible seed damage values were 8.821, 7.012 and 8.44% at separating time of 10, 15 and 20 seconds respectively, for drum speed of 28.85 m/s, feed rate of 12.86 kg/min. and 8 drum fingers. The number of fingers of 12 accomplished the minimum values of invisible seed damage compared with 8 drum fingers for all drum speeds and feed rates. Generally, the developed threshing drum decreased the invisible seed damage for all the studied variables compared with the threshing operation before development. The decrement reached 16.4% compared to machine before development.


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T hre s hing t im e , 10 s e c o nd_ _ 8 F inge rs - - 12 F inge rs

0

0.2

0.4

0.6

0.8

24.25 25.81 27.33 28.85

Vis

ible

see

d d

amag

e, %


0

0.5

1

1.5

2

2.5

24.25 25.81 27.33 28.85

Un

thre

shin

g s

eed

s, %

T hre s hing t im e , 2 0 s e c o nd_ _ 8 F inge rs - - 12 F inge rs

0

0.5

1

1.5

2

2.5

24.25 25.81 27.33 28.85Drum speed, m /s

Un

thre

shin

g s

eed

s, %


0

0.2

0.4

0.6

0.8

24.25 25.81 27.33 28.85Drum speed, m /s

Vis

ible

see

d d

amag

e, %


0

0.5

1

1.5

2

2.5

24.25 25.81 27.33 28.85

Un

thre

shin

g s

eed

s, %


0

0.2

0.4

0.6

0.8

24.25 25.81 27.33 28.85

Vis

ible

see

d d

amag

e, %

threshing timem, 5

4

8.57 12.86 17.14 21.43Feed rate, kg/min.

Fig. 6: Effect of drum speed, feed rates and Fig. 7: Effect of drum speed, feed rates and threshing time on unthrshing seeds threshing time on visible seed damage under different number of drum fingers. under different number of drum fingers.


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Total seed damage:

Fig. 9 shows the effect of drum speed, feed rate and separating time on total seed damage for two different numbers of drum fingers. The results indicated that total seed damage increased as the drum speed was increased when other variables were kept constant. At feed rate of 8.57 kg/min. when the drum speed increased from 24.25 to 28.85 m/s, the total seed damage increased from 5.951 to 10.127%. When the feed rate increased at constant other variables, the total seed damage decreased for the developed threshing machine. When the feed rate increased from 8.57 to 21.43 kg/min. the total seed damage decreased from 5.951 to 2.515% at drum speed of 24.25 m/s, separating time of 10 seconds and drum fingers of 8.

The number of fingers on the threshing drum of 12 and the separating time of 15 seconds gave the lowest values of total seed damage for all the drum speeds and feed rates. The total seed damage increased by 58.4 and 40% when the separating time decreased and increased than 15 seconds at feed rate of 17.14 kg/min., drum speed of 25.81 m/s and 8 drum fingers. However, developing the threshing drum of the stationary thresher tended to decrease the total losses by 17.3% compared to the thresher before modification for all the studied variables.

Threshing efficiency:

Fig. 10 illustrates the effect of drum speed, feed rate, separating time and drum fingers on threshing efficiency. The results indicated that the threshing efficiency increased as the drum speed was increased when other variables were kept constants. At feed rate 8.57 kg/min. when the drum speed was increased from 24.25 to 28.85 m/s the threshing efficiency increased from 91.7 to 92.88% at number of fingers of 8 and separating time of 10 seconds. On the other hand, when the feed rate was increased from 8.57 to 21.43 kg/min. the threshing efficiency decreased from 91.70 to 89.951% at drum speed of 24.25 m/s. Generally, when the feed rate increased as constant drum speed, the threshing efficiency decreased. For the separating time of 15 seconds and number of finger on the threshing drum of 12 fingers, the maximum threshing efficiency (96.92%) was obtained was drum speed of 28.85 m/s and feed rate of 8.57 kg/min.

Energy requirements:

Fig. 11 shows the effect of drum speed, feed rate and separating time on the energy required for threshing of seeds flax under two different levels of drum fingers. The results indicated that the obtained values of energy were 1.26, 1.61, 1.91 and 2.12 kW at drum speeds of 24.25, 25.81, 27.33 and 28.85 m/s respectively, with feed rate of 21.43 kg/min. and separating time of 10 seconds. It was clear that the energy consumed increased by 68.3% as a result of increasing the drum speed from 24.25 to 28.85 m/s. It was also


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0

0.2

0.4

0.6

0.8

24.25 25.81 27.33 28.85

Vis

ible

see

d d

amag

e, %


0

0.5

1

1.5

2

2.5

24.25 25.81 27.33 28.85

Un

thre

shin

g s

eed

s, %


0

0.5

1

1.5

2

2.5

24.25 25.81 27.33 28.85Drum speed, m /s

Un

thre

shin

g s

eed

s, %


0

0.2

0.4

0.6

0.8

24.25 25.81 27.33 28.85Drum speed, m /s

Vis

ible

see

d d

amag

e, %


0

0.5

1

1.5

2

2.5

24.25 25.81 27.33 28.85

Un

thre

shin

g s

eed

s, %


0

0.2

0.4

0.6

0.8

24.25 25.81 27.33 28.85

Vis

ible

see

d d

amag

e, %

threshing timem, 5

4

8.57 12.86 17.14 21.43Feed rate, kg/min.

Fig. 8: Effect of drum speed, feed rates and Fig. 9: Effect of drum speed, feed rates and threshing time on invisible seed threshing time on total seed damage damage under different number of under different number of drum fingers. drum fingers.


341

threshing timem, 5

4

8.57 12.86 17.14 21.43

T hre shing t im e , 2 0 s e co nd__ 8 F ingers - - 12 F inge rs

88

91

94

97

100

24.25 25.81 27.33 28.85Drum speed, m /s

Th

resh

ing

eff

icie

ncy

, %

T hre shing t im e , 10 s e co nd_ _ 8 F inge rs - - 12 F inge rs

88

91

94

97

100

24.25 25.81 27.33 28.85

Th

resh

ing

eff

icie

ncy

, %

T hre shing t im e , 15 s e co nd_ _ 8 F inge rs - - 12 F inge rs

88

91

94

97

100

24.25 25.81 27.33 28.85

Th

resh

ing

eff

icie

ncy

, %

T hre s hing t im e , 10 se c o nd_ _8 F inge rs - - 12 F inge rs

1

1.5

2

2.5

3

3.5

4

24.25 25.81 27.33 28.85

Co

nsu

med

po

wer

,kW

T hre s hing t im e , 15 se c o nd_ _8 F inge rs - - 12 F inge rs

1

1.5

2

2.5

3

3.5

4

24.25 25.81 27.33 28.85

Co

nsu

med

po

wer

,kW


1

1.5

2

2.5

3

3.5

4

24.25 25.81 27.33 28.85Drum speed, m /s

Co

nsu

med

po

wer

,kW

Feed rate, kg/min.

Fig.10: Effect of drum speed, feed rates and Fig. 11:Effect of drum speed, feed rates and threshing time on threshing efficiency threshing time on consumed power under different number of drum fingers under different number of drum fingers


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evident that for all drum speeds, separating times and drum fingers, the energy consumed during deputation of flax seeds increased when the feed rate increased. Increasing the feed rate from 8.57 to 21.43 kg/min. tended to increase the energy consumed by 21.9% at drum speed of 25.81 m/s. separating time of 10 seconds and 8 drum fingers. However, the minimum values of drum speed and feed rate accomplished the lowest values of energy consumed for all separating times and drum fingers.

The results also, indicated that the separating time of 10 seconds and number of drum fingers of 8 achieved the minimum values of energy consumed during the separating operation of flax seeds for all drum speeds and feed rates. Generally, the energy consumed by using the developed thresher was less than by this machine before developing for all the studied parameters. This may be attributed to increase in threshing efficiency and decrease in time required for separating operation in case of using the developed thresher compared with the same thresher before its development.

CONLUSIONS

The obtained data revealed the following points:

The lowest values of seed and stalk damages and energy requirements were recorded with the highest values of feed rate for all the drum speeds, separating times and number of fingers. The total seed damage decreased by 59.5%, when the feed rate increased from 8.57 to 21.43 kg/min. at 24.25 m/s drum speed, separating time of 10 seconds and 8 drum fingers.

1. The feed rate of 21.43 kg/min., drum fingers of 12, drum speed of 28.85 m/s and separating time of 15 seconds gave the maximum value of seed output (3.51 kg/min.) for modification threshing machine compared to the other ranges of the feed rate and drum speed. However, the increments of seed output were 60 and 16.7 %, when the feed rate was increased from 8.57 to 21.43 kg/min. and the drum speed was increased from 24.25 to 28.85 m/s, respectively.

2. For all feed rates, separating time and drum fingers, decreasing the drum speed tends to decrease the seed losses, seed damage, threshing efficiency and energy requirements. The energy required for threshing the flax seeds decreased by 40.6% when the drum speed was decreased from 28.85 to 24.25 m/s at feed rate of 21.43 kg/min. and separating time of 10 seconds.

3. The optimum conditions for operating the developed threshing machine which gave the maximum threshing efficiency was drum speed of 28.85 m/s, feed rate of 8.57 kg/min. and separating time of 15 seconds with 12 drum fingers.


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4. The local developed threshing machine achieved the maximum values of seed output and threshing efficiency in addition to the minimum values of total seed losses, stalks damage and energy requirements for all the drum speeds and feed rates, compared with the machine before development.

REFERENCES

Badway, M. E. (2002). Modification and evaluation of paddy rice thresher to suit flax deseeding. Misr J. Ag. Eng., 19(4): 881-900.

Duncan, D. B. (1955). Multiple range and multiple F. test. Biometrics, 11:1-42.

El-Ashry, A. S.; A. El-Rayes and G. R. Gamea (2003). A comparative study of flax threshing systems and their effects on yield components quality. Misr J. Ag. Eng., 20(3): 691-701.

El-Behiry, A. A.; M. I. Ward and A. M. El-Sherbieny (1997). Performance evaluation of some wheat thresher machines under different conditions. Misr J. Ag. Eng., 14 (4): 149-160.

El-Haddad, W. Z. (2000). A simplified design and performance study of threshing and winnowing machine suitable for sample holdings. M. Sc. Th. Agric. Mech., Fac. of Agric., Kafr El-Sheikh, Tanta Univ.

Embaby, A. T. (1985). A comparison of the different mechanization systems for cereal crop production. M. Sc. Th., Ag. Eng., Cairo Univ.

Gol, A. K. and S. K. Nada (1991). Performance of power operated groundnut pod stripper. AMA, 22(3): 25-28.

Gummert, M. (1991). IRRI Thresher Performance Special International Rice Res. Inst. Nov. 26:1-20.

Helmy, M/ A. (1988). Threshing parameters affecting the performabce of local and foreign wheat threshing machines. Misr J. Ag. Eng., 5(4): 329-343.

Huynh, V. m.; T. Powell and J. N. Siddal (1982). Threshing and separating process-A mathematical model. Trans. ASAE, 25(1): 62-73.

Kepner, R. A.; R. Bainer; and E. L. Barger (1982). Principles of farm machinery. Wiley and Sons Inc., N. Y.

Mishram, T. N. and K. Desta (1990). Development and performance evaluation of a sorghum thresher. Agric. Mech. In ASIA, 21(3): 33-37.


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Mohamed, A. H. A. (1994). Optimization of power rice for locally manufactured machine. M. Sc. Thesis, Agric. Eng. Fac. of Agric., Ain Shams Univ.

Snedecor, G. W. and W. G. Conchran (1980). Statistical method 7th Ed. Iowa State Univ. Press. Ames. Iowa, USA.

Szarszunov, W. A. (1998). Selection of design parameters of a roller assembly for flax threshing, problem inzynierioiniczej: 4, 63-73; 3 Ref.

الملخص العربي

تطوير درفيل آلة دراس ثابتة ليالئم ھديرالكتان

٣*زكريا محمد عمارة

ه تعتبر عملية ذا فان ذور، ل اف والب ة األلي ھدير الكتان من العمليات الھامة المؤثرة على جودة وإنتاجيل تل دراس وتقلي ة ال اءة عملي ع كف ع رف ان م دير الكت ة ھ ام بميكن ان االھتم ة بمك اف من األھمي ف األلي

تخدام آالت را الس ائي للمحصول، ونظ د النھ ادة العائ ى زي نعكس عل ا ي ذور مم يما والب دراس والس الاع الثابتة منھا فترة محدودة على مدار العام مما يؤدى إلى انخفاض السعة التشغيلية لآللة وبالتالي ارتف

و ت ث ھ ذا البح ن ھ ي م دف الرئيس ان الھ ذا ك دراس ، ل ة ال اليف عملي ة تك ة دراس ثابت يم أداء آل عظا( ة ) مصنعة محلي وير بورش ة التط ت عملي د أجري ان ، وق دير الكت يالئم ھ دراس ل ل ال وير درفي بتط

دراس بمركز ٢٠٠٣خاصة بكفر الشيخ عام الزم لل زمن ال م وتم تصميم دائرة الكترونية للتحكم قي البمحطة ) ١صنف سخا (حصول الكتان ميكنة األرز بميت الديبة، واختبرت اآللة المطورة باستخدام م

خا ة بس ر ال –البحوث الزراعي ة كف د ، يخشمحافظ ة ظروف النسب ألتحدي ذه اآلل غيل ھ ة لتش المالئم :العوامل التاليةوقد قيمت اآللة المطورة تحت والتي تعطى أحسن أداء وأقل تكاليف،

.ث/م ٢٨.٨٥، ٢٧.٣٣، ٢٥.٨١، ٢٤.٢٥أربع سرعات خطية للدرفيل وھى .١ .دقيقة/كج ٢١.٤٣، ١٧.١٤، ١٢.٨٦، ٨.٥٧أربعة معدالت تغذية وھى .٢مجموعات بكل ٥األول يتكون من ( مصنوعة من المطاطنوعين من الدرافيل ذات أصابع .٣

).أصبع ١٢مجموعات بكل مجموعة ٥والثاني يتكون من ، أصابع ٨مجموعة ).ثواني ٢٠، ١٠،١٥( ثالثة أزمنة لتعريض البذور للدراس .٤

:تأثير العوامل السابقة على المؤشرات اآلتية قد تم دراسةو

ذور -السيقان التالفة –إنتاجية اآللة ر المدروسة نسبة فاقد الب ر –غي نسبة التلف الظاھري وغي . المستھلكة في التشغيلطاقة ال –كفاءة الدراس – للبذورالظاھري

:وأوضحت النتائج االتى

يقان/كج ٢١.٤٣أن معدل التغذية .١ ذور والس ة د أعطى أقل القيم لكل من تلف الب والطاقدراس ة ال دار المستھلكة فى عملي ذور بمق ة لتلف الب د ٪٥٩.٥ونقصت النسبة الكلي عن

الجيزة - معھد بحوث الھندسة الزراعية - مركز ميكنة األرز - باحث أول ٣*


345

ث وزمن /م ٢٤.٢٥د سرعة درفيل د عب/كج ٢١.٤٣إلى ٨.٥٧زيادة معدل التغذية من .أصابع ٨راس ذو ثواني باستخدام درفيل الد ١٠دراس

ة .٢ دل التغذي ى مع د أعط ج ٢١.٤٣لق ل دراس د وس/ك ن /م ٢٨.٨٥رعة درفي ث وزمة ١٥ دراس يم اإلنتاجي ى الق واني أعل ج ٣.٥١(ث ي ). ك ادة ف بة الزي ت نس ة بلغ عام

.ث/م ٢٨.٨٥إلى ٢٤.٢٥عند زيادة سرعة درفيل الدراس من ٪١٦.٧اإلنتاجية

ى نقص تلف .٣ درفيل أدى إل دراسو أن نقص سرعة ال اءة ال ذور وكف د الب ة فواق والطاقد تھلكة عن دراسالمس ة ال ة وأزمن دالت التغذي ع مع ة جمي ي الدراس تخدمة ف غ . المس وبل

ي نقص ف دراس ال ة ال ي عملي تھلكة ف ة المس نقص سرعة ٪٤٠.٦حوالي الطاق ة ل نتيج .ث/م ٢٤.٢٥إلى ٢٨.٨٥درفيل الدراس من

دراس الثابالظروف المثلى لتشغيل آلة ا .٤ دراسل وم ب ة المطورة لتق اءة ت ان بكف ذور الكت بة دل تغذي ان ھي استخدام مع اف الكت ذور وألي عالية وبأقل فواقد وتلف ممكنة لكل من ب

ج ٨.٥٧ دراس /ك ل ال رعة درفي ن /م ٢٨.٨٥د، س يقان (دراس ث، وزم ريض الس تع .إصبع ١٢ثواني ودرفيل مثبت علية ١٥) للدراس

ة ھديرالثابتة ليالئم دراسأن تطوير درفيل الدراس آللة ال .٥ د حسن في أداء اآلل الكتان قى زي دراسالمطورة، مما انعكس عل اءة ال ة وكف ائي، فضال عن ادة إنتاجي د النھ والعائ

. تقليل الفواقد الكلية وتلف البذور وتلف ألياف محصول الكتان


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Misr J. Ag. Eng., 23(2): 324-345 FARM MACHINERY AND POWER … · 2010-06-20 · Misr J. Ag. Eng., April 2006 326 and concave clearance. These variables are also related to the threshing