Volume 22
Issue 4
Agricultural Engineering
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
DOI:10.30825/5.ejpau.178.2019.22.4, EJPAU 22(4), #02.
Available Online: http://www.ejpau.media.pl/volume22/issue4/art02.html
SMALLSCALE HEAD OF COMBINE FOR HARVESTING SESAME
DOI:10.30825/5.EJPAU.178.2019.22.4
Pourya Bazyar^{1}, Ali Jafari^{1}, Reza Alimardani^{1}, Valiollah Mohammadi^{2}
^{1} Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran
^{2} Department of Agronomy and Plant Breeding, College of Agriculture, University of Tehran, Karaj, Iran
Sesame plants are harvested manually and mechanized. As the cultivation area of this product is increasing in the world, due to the excessive grain loss in the head of combine harvester and the toxic spray called Regelon, which is a human health hazard, the need to make a special head of combine for harvesting sesame has been the manufacturers focus of attention. In this research, a special smallscale head of combine harvesting for sesame made up bowl fingers and stair frame has been fabricated and evaluated. As the results have showed farm capacity of the machine with a working width of 60 cm and a speed of 1.3 m/s is 217 m^{2}/hr. Also, the results of the SolidWorks analysis indicate a maximum displacement of 0.057 mm, a maximum strain of 0.0000407, and a maximum von Mises Stress of 8929 KN/m^{2}, in triangular bowl fingers under load 26 N by a stem of Sesame. moreover, the head loss of this special head is about 16 percent.
Key words: head of combine, harvesting, sesame.
INTRODUCTION
The sesame is thermophilic and basically, a particular product for tropical and subtropical regions and is sensitive to low temperatures [2], but by implementing a breeding program, it is possible to extend its cultivation to temperate regions. Sesame seed is from 40 degrees of north latitude to 40 degrees south latitude, it is usually cultivated at a height of 1200 meters above the sea level. This plant needs warm weather and an abundant amount of light and shows low sensitivity to the heat [12]. Some physical properties of sesame at the moisture of 3.4% with average dimensions of length, width, and thickness of 2.80, 1.69 and 0.82 mm, and the mean geometric diameter, spherical, area, and density were 56.1 mm, 56/0, 80/7 mm and 1224 kg /m2. The average friction coefficient ranged from 0.39 on the glass to 0.54 on the plywood, while the repose angle was 32 ± 0° [14]. Sesame is harvested when the seeds are ripe in the lower capsule. Capsules usually come up from the bottom of the stem, and the left loss begins, but the capsules are still green and they must be removed before they dry [6]. Sesame is a strategic product with high nutritional and medical value, that the daily increase in number of the lands under cultivation due to sesames high consumption in the world and to make some reductions in harmful effects of spraying in order to increase plant resistance to seed loss, are the reasons which necessitate the mechanized harvesting of this product [3]. As the cultivation area of this product is increasing in the world, there are numerous industrial and pharmaceutical properties for sesame. Nowadays, the consumption of sesame oil in the world is increasing, but because of the high head of combine loss in common combines, it is often taken manually in some countries, which is, costly and timeconsuming and in some other countries it is carried out by combine harvesters which is a special head of combine harvester for finegrained products, In this case, the losses rate is too high [9]. According to the research on the physical and mechanical properties of some finegrained products and the need for the use of special heads of combine harvesters and machines for their harvesting. In this research, the activities carried out in the field of construction and design of these hedges and harvest machines have been studied. In 2015, Wu Yingbing invented a single saw reaper for harvesting sesame. Which provided the farmer a mechanical sesame harvest. One of its advantages is the moving sheet for the collection of lost grain, and its disadvantage is the lack of a lost grain transferring system into a grain collection tank [16]. In 2017, Dai Jin, et al. invented a simple and easytouse machine for harvesting small blocks of sesame. Its advantage is its property for smallscale, and its disadvantage is that the machines just reap the product and there is not any system to reduce sesame seed loss. Also, this reaper cannot be used for large sesame fields [1]. In 2028, Li Fawang, et al. invented a reaper for sesame seeds. This reaper includes the frame, the shear shaft, a Valve, transfer position, and the cylinder. The advantage of this reaper is the existence of a rotary system to ease the entry of plants stems into the cutting chamber. And its disadvantage is the lack of a system for collecting lost grain in the cutter section of the reaper [10]. In 2018, Wang Yuan invented the semiautomatic harvesting machine for sesame. This machine includes a handwheel, a battery, a collecting tank, transport vehicles, a cutting unit and a group of levers located at the rear end of the battery on a moving carrier. Its advantage is the easy entrance of the product into the cutting chamber, and its disadvantages can be the lack of a system for collecting lost seeds and also a cutting edge ahead of the levers and feed rollers and the consequent seed loss increase [15].
In this research, a smallscale head of combine harvester for harvesting sesame was manufactured and evaluated in order to achieve the following objectives:
 Reducing the seed loss in the head of the combine harvester
 Collecting the lost grains
 Facilitation of transportation
MATERIALS AND METHODS
In this research, several designs have been evaluated and simulated. Then, the best plan is chosen. After that, it is examined by harvesting canola this is due to the fact that there is no sesame in Karaj in this period.
Design assumptions
 Using the overlapped bowl fingers will reduce the grain loss in the head of the combine and will result in their collection inside the fingers.
 Using tall separators with covered sheets will reduce the grain throwing to the sides.
 The sloping design of the bowl fingers will cause the seeds to fall from the inside of the bowl fingers into the tank.
 Using a Hedge trimmer to cut the product reduces the intensity of the stem cutting and, consequently, reduces the throwing of grain on the ground.
Design specification
In the design of the desired harvest head of combine (Fig. 1), consist of the four sloping triangular bowl fingers and a stair frame, which was 20 degrees angular to the horizon to aid in the collection of lost seeds in the tank, because according to a test carried out by slope gauge (Fig. 2), the sesame starts to fall on a ferrous plate with a slope of 20°. A hedge trimmer is also used to cut the plant stem. Other specifications of the machine and specifications of the hedge trimmer are also given in Table 1 and Table 2 respectively.
Table 1. Machine Specifications 
working width [cm]  60  Dimensions of the blade [cm]  20*30 
Machine weight [kg]  38  Dimensions of the profile [cm]  2*2 
Machine volume [m]  0.04  Sheet thickness [cm]  2 
Center of gravity [m]  X = 0.65, Y = 0.75, Z = 1.02  Angle between two blades [degrees]  108 
tank volume [m3]  0.216  Machine height [m]  1/3 
Fig. 1. Harvesting canola 
Fig. 2. Connecting the smallscale head of combine harvester to carriage 
In this head of combine harvester, the hedge trimmer made in Germany used for cutting the product has the Specifications (Tab. 2) below [4]:
Table 2. Specifications of the hedge trimmer 
Model  Hedge Trimmer Stihl HS82R 
Motor specifications  Power: 1.1 horsepower / displacement capacity 22.7 cc Twostroke / Gasoline / Cool Air Handley 
Fuel tank capacity  600 Milliliters 
machine performance  Fuel system: Gasoline with oil mixture • Cutting blade length: 60 cm Double side • Overall length: 120 cm • The volume of the device in a distance of 7 meters: 94 to 107 decibels (DB) 
Weight [kg]  5/4 
Due to the total mass of the machine (m) is obtained from the sum of the mass of the chassis (mh) and the hedge trimmer mass (mht), then for moving the machine in the worst ground conditions (ground with a slope of 30 degrees) to a worker with 639 Newtons tensile force is required by Equation 1. The forward speed is also 0.2 m/s. According to Equation 2 [11], its tensile power will be 128 watts.
(1) 
(2) 
The required power to cut the stems of the sesame plant is obtained by Equation 3, in which P_{cut} (Cutting power in kW), F_{xmax} (Maximum cutting force per KN), X_{bu} (Material depth at the beginning of blade contact), f_{cut} (Cut number per minute), C_{F} (Average force to maximum force ratio (0 < CF < 1)) [13].
(3) 
Harvesting rapeseed with small scale head of the combine
Canola harvesting was done at the Seed Breeding Research Institute field. The height of the head of combine from the ground was set to 35 cm (Fig. 4). After plotting (Fig. 5), a number of stems and the number of spikes in each plot were calculated (Fig. 5) and then harvesting was done (Fig. 3). After harvesting, the machine was pulled back. The stems harvested were collected in the tank (Fig. 6). Then the number of spikes harvested was counted (Fig. 7) and the number of spikes inside the tank was collected and the spikes inside the bowl fingers were also counted (Fig. 8). The total number of spikes harvested by the apparatus was calculated from the sum of the spikes counted inside the tank, and the bowl fingers and spikes harvested by the apparatus were obtained. After calculating the total number of harvested spikes per plot, the same operation was performed for the other species. After calculating the number of spikes harvested per plot, the number of grains harvested per spike was counted (Fig. 9). For this purpose, ten spikes were selected randomly and their number of grains was calculated. After calculating the number of grains often spikes, their average grains were calculated that were 20 grains. After calculating the average number of grains per spike, the number of grains harvested by the machine per plot was obtained from the Equation 12. Then the total number of grains per plot was calculated. To calculate the total number of grains per plot, we obtained Equation 12.
Fig. 3. Separating plots with rope 
Fig. 4. Stems which are collected in the tank 
Fig. 5. Counting harvested spikes on nylone 
Fig. 6. Stakes which are gathered in bowl fingers and tank 
Fig. 7. Counting seeds of each stake 
Fig. 8. Smallscale head of combine for harvesting sesame 
Fig. 9. Sesame slope gauging test 
C = A × B  Eq. 12 
In this equation, "C" the number of grains harvested by machine per plot, "A" the number of spikes harvested by machine per plot, and "B" the average number of calculated grains.
In Equation 13, "Z" the total number of grains per plot, "X" the total numbers of spikes per Solidworks and "Y" the average calculated grains.
Z = X × Y  Eq. 13 
Determination of loss in the head of the combine harvester in Canola harvesting
Initially, ten rape seeds were selected and the number of available seeds was calculated after knocking them. Then their averages were obtained. The level of the harvest was considered and the number of plants was counted. By multiplying the number of plants by the mean number of grains, the total number of grains was obtained. The plants harvested were then crushed and the number of harvested grains was calculated. As the total area of the four plots is 2.4 square meters, the average total grain yield was harvested in this area and then, using a thousand seed weight of rapeseed which equals 4 g [8]. Seeds function were harvested in kg/ha. Then, the percentage of the smallscale head of combine losses was calculated using Equation 14.
Percentage of head loss = = (Function of total grain – Function of harvested grain) / Function of total grain × 100 
Eq. 14 
RESULTS AND DISCUSSIONS
Considering the topics mentioned in different sections of the research, the results of this study are analyzed in two parts of practical results and simulation results
Practical Results
According to the topics discussed in this research, this machine has advantages over other designs, such as bowl fingers and stair frame mechanism existence that reduces the grain loss amount to the lowest possible level, in addition, the design of these fingers like bowls helps the lost grains collection. Also, their sloping installation leads the grains to the tank. In this head of combine harvester, there are also long separators with a nylon cover to reduce the throwing of the seeds to the sides of the head of combine harvester. The head of combine harvester in this study has a lower weight than other designs that were mentioned. As a result, this head has high portability and maneuverability. This head has the lowest power consumption and due to the use of the simplest mechanisms, its production is economic.
Field test of the machine
Table 1 shows the results of canola harvesting in Plot one, whereby the number of harvested grains was 29 694. Table 2 shows the results of canola harvesting in Plot Two, whereby the number of harvested seeds was 62 520. Table 3 shows the results of the canola harvest in Plot Three, whereby the number of harvested seeds was 42 476. Table 4 shows the results of canola harvesting in Plot Four, whereby the number of harvested seeds was 41 580. Table 5 shows the results of canola harvesting in Plot Two, whereby the number of harvested seeds was 49 200. Table 6 shows the results of canola harvesting in Plot Two, whereby the number of harvested seeds was 36 100.
According to the rapeseed yield in the area of study in harvesting time by the manufactured head of combine, total grain yield was 5200.66 and harvested grain yield was 4359.53 kg/ha. The results show the loss rate in the head of combine in Table 10. According to the calculation of casualties in this head of combine, an average of 16% was estimated. The casualty results of conventional combines calculated by Izadinia et al. [2005] are shown in Table 11, which averages 17% of the average casualties. The head of combine loss in this study was lower than the conventional combines for seed products [5].
Table 3. Harvested quantities in plot 1 
Title  Value (number) 
Number of shoots  40 
The total number of spikes  2016 
Number of spikes harvested  1323 
Total number of grains  40320 
Number of grains harvested  29540 
Number of grains inside the tank and bowl  154 
Table 5. Quantities harvested in Plot 3 
Title  Value (number) 
Number of shoots  50 
The total number of spikes  2520 
Number of spikes harvested  1920 
Total number of grains  50400 
Number of grains harvested  42280 
Number of grains inside the tank and bowl  196 
Table 6. Harvested quantities in Plot 4 
Title  Value (number) 
Number of shoots  54 
The total number of spikes  2722 
Number of spikes harvested  1856 
Total number of grains  54440 
Number of grains harvested  41370 
Number of grains inside the tank and bowl  210 
Table 7. Harvested quantities in Plot 5 
Title  Value (number) 
Number of shoots  54 
The total number of spikes  3033 
Number of spikes harvested  2460 
Total number of grains  60660 
Number of grains harvested  48974 
Number of grains inside the tank and bowl  226 
Table 8. Harvested quantities in Plot 6 
Title  Value (number) 
Number of shoots  54 
The total number of spikes  2136 
Number of spikes harvested  1805 
Total number of grains  42720 
Number of grains harvested  35958 
Number of grains inside the tank and bowl  142 
Table 9. Loss Quantities in the manufactured machine 
Losses  Value (number) 
Crete 1  10626 
Crete 2  978 
Crete 3  7924 
Crete 4  12860 
Crete 5  11470 
Crete 6  6620 
Percentage of casualties  16 
Table 10. Shedding values in combines commonly used in rapeseed harvest [Izadinia et al., 2005] 
Decrease amount [kg/ha]  Platform type  
Total shedding  Horizontal cutting shoulder center  Horizontal cutting shoulder  Lateral cut shoulder  
599.35  106.46  492.89  0  conventional grain platform 
17  –  –  –  Average percentage of casualties 
Simulation results
The following results were obtained from Solidworks 2018 software analyzing the bowl finger. According to the results of simulation in the software, the middle part of the bowl finger (node 413) under the force of 26 N [7] has the most displacement, and the blade damage possibility is high in this part. However, because the tension is less than the yield stress, there is no need for modifying the construction. The amount of strain and von Mises Stress also occur at the corners of this head are also in element 197 and node 78, which is modified by using the finger's welding connection to the stair frame.
Table 11. Material Properties 
Model Reference  Properties  
Name:  Ductile Iron  
Model type:  Linear Elastic Isotropic  
Default failure:  Max von Mises Stress  
Yield strength:  5.51485e+08 N/m^2  
Tensile strength:  8.61695e+08 N/m^2  
Elastic modulus:  1.2e+11 N/m^2  
Poisson's ratio:  0.31  
Mass density:  7100 kg/m^3  
Shear modulus:  7.7e+10 N/m^2  
Thermal:  1.1e05 /Kelvin  
Force:  26 N 
Table 12. Mesh Information 
Model  Information  
Mesh type:  Shell Mesh Using Midsurfaces  
Mesher Used:  Standard mesh  
Jacobian points:  4 Points  
Element Size:  7.86215 mm  
Tolerance:  0.393108 mm  
Mesh Quality:  High 
Table 13. Study results 
Model Reference  Type  Min  Max 
Displacement  0.000e+00 mm Node: 1 
5.756e02 mm Node: 413 

Strain  9.238e09 Element: 626 
4.074e05 Element: 197 

von Mises Stress  9.028e+02 N/m^2 Node: 360 
8.929e+06 N/m^2 Node: 78 
CONCLUSIONS
This research has done based on studies on the harvest of sesame plants. After present studies on fabrication designs and their advantages and disadvantages; it has been attempted that in addition to decreasing the amount of seed loss in the head of the combine harvester, the disadvantages of other mentioned machines such as transferring grain to the tank, collecting lost grains, reducing the grain throwing to sides have been resolved. Researchers can also make future studies on the generalization of this system or the ways of connecting the head of combine harvester to the combine harvester and also ways of optimizing this design. In the end, it is better to harvest other finegrained products by this machine in order to ensure its efficiency.
Acknowledgements
Thanks to the Authorities at the workshop of the Department of Biosystem Engineering at the University of Tehran who helped us with this research.
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Received: 9.07.2019
Reviewed: 15.08.2019
Accepted: 16.12.2019
Pourya Bazyar
Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran
Tel: (+98)9363213201
email: pourya.bazyar@ut.ac.ir
Ali Jafari
Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran
Reza Alimardani
Department of Agricultural Machinery Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran
Valiollah Mohammadi
Department of Agronomy and Plant Breeding, College of Agriculture, University of Tehran, Karaj, Iran
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