Scientific report: "The separation of the particles through the trough parts dam dam dam and several empty grain saving function" docx

J. Sci. Dev. 2009, 7 (Eng.Iss.1): 79 - 84 HA NOI UNIVERSITY OF AGRICULTURE 79 Grain separation by the concave and remaining grain of a multiple cylinders threshing system Sự tách hạt qua máng đập của bộ phận đập nhiều trống đập và hàm lưu hạt Le Minh Lu and Nguyen Xuan Thiet Faculty of Engineering, Hanoi University of Agriculture TÓM TẮT Đập và tách hạt là quá trình quan trọng trong việc thu hoạch lúa (lúa nước; lúa mì) và tốn nhiều năng lượng. Đã có nhiều nghiên cứu về bộ phận đập nhiều trống đập để cải tiến máy gặt đập liên hợp được giới thiệu trong nhiều năm gần đây. Nghiên cứu bộ phận đập hai trống đập kiểu tiếp tuyến với hướng cấp liệu tiếp tuyến đã được thực hiện năm 2007 với mục đích: tăng khả năng tách hạt của bộ phân đập, giảm chi phí năng lượng đập, giảm tác động làm vỡ hạt và rơm vụn. Kết quả nghiên cứu cho thấy năng lượng đập đã giảm đi khi cấp liệu tiếp tuyến, vật liệu đập (rơm, hạt ) bị giập nát, gẫy vụn ít hơn do đó tăng khả năng phân tách hạt qua máng đập. Sự sắp xếp hai trống đập liên tiếp thuận theo hướng chuyển động của dòng nguyên liệu cũng làm tăng chiều dài của máng đập do đó làm giảm đáng kể lượng hạt còn lưu lại theo rơm ra khỏi máng đập. Bài báo này cung cấp một số kết quả nghiên cứu chính về sự tách hạt khỏi máng đập, lượng hạt lưu lại theo rơm sau bộ phận đập và phân tích ảnh hưởng của một số thông số chính như góc cấp liệu và chiều dài máng đập. Mô hình toán học về quá trình tách hạt khỏi bộ phân đập cũng được giới thiệu. Từ khóa: Bộ phận đập nhiều trống đập, máy gặt đập liên hợp, sự tách hạt qua máng đập. SUMMARY Threshing and separation is one of the most important processes during harvesting of rice and wheat, and consumes a large of engine power. A number of studies for improving combine harvester with a multi-drum threshing system have recently been introduced. Study on two-cylinder tangential threshing system with tangentially fed was done in 2007 with purposes: to improve separation capacity, reduce fuel consumption and reduce the amount of broken grain and straw damage. The research results showed that energy will be reduced with tangentially fed. The threshing material have broken little thereby increasing the separation ability of the threshing unit. The arrangement of both cylinders, one behind the other in the direction of the material-flow, are also increase the length of the concave so reduce the remaining grain. This paper presents some main research results of grain separation by the concave, remaining grain and analyze the influence of the main parameters feeding angle and concave length. The mathematical model of grain separation in threshing units are presented. Key words: Combine, grain separation, multi-drum threshing system, threshing unit. 1. INTRODUCTION Climbing The task of threshing system is the removing the grains, i.e. extracting the grains from the infructescence, like ears, panicle or caps, by striking and rubbing as well as separating the grains from the straw. For further grain separating the cleaning unit is arranged next to the threshing unit, which design depends partially on the structure of the threshing system (Arnold, 1964; Huynh, 1982; Wacker, 1995). It is necessary to improve the threshing system to perform efficiently and also for the machine is valid: increasing total throughput; improving of the grain separation; lowering of the grain losses. In this paper, the results of lab tests on two- cylinder tangential threshing system for the grain separation and the remaining grain with different feeding angle, concave clearance and specific throughput are given. A general and plain mathematical description of this process would allow a theoretical prediction of Grain separation by the concave and remaining grain of a multiple cylinders threshing system 80 the effect of the parameters variations involved, comparing it with experimental results and obtaining some ideas about the desired configuration of the cylinder-concave set (Beck, 1999; Gieroba, 1992; Kutzbach, 2000). Through analyzing the results of lab tests with the help of the software Origin, two mathematical functions have been found. 2. MATERIALS AND METHODS The basic setup of the test stand is shown in Fig. 1. The lab test was done with winter wheat 2006. The crop material is prepared on a storage belt 1 and tangentially fed to the rasp bar cylinder 3 and 4 by means of a feeding mechanism1 and 2. The grain and material other than grain (MOG) separated underneath the concave during the test are collected in classes 1… 5 (m k1 …m k5 ). The remaining material that is discharged from the second cylinder is post - processed using classical straw walkers to separate grain m k6 that is still contained within the MOG (class 6). The feeding angle () is varied in three steps from 50° through 60° to 70°. Fig. 2 shows the test stand in the lab. The concave clearance at the primary cylinder (DT1) is defined with the dimensions S 1 , S 2 , S 3 and S 4 . The concave clearance can be modified by changing the length of the connections L 1 through L 5 of the concave support (Fig. 3). Fig. 1. Test stand Fig. 2. Test stand in the lab Fig. 3. Layout of primary cylinder and concave Le Minh Lu, Nguyen Xuan Thiet 81 3. RESULTS AND DISCUSSION For the evaluation of the concave length the integral of grain separation (S Ki ) and remaining grain (R Ki ) as defined in Eq. (1) and Fig. 4 was derived out of the measured grain masses gathered at the different classes. 100 1 1      i j k i j kj jKjKi m m lAS %; R Ki = (1 - S Ki )*100%; 100* jk kj kj lm m A   % (1) The tests have shown that very few grains are separated at the first class (Fig. 5). This is typical behavior of a tangential threshing unit, since kernels have to be removed from ears first. At the end of the second class approx. 50% of the grain is separated. Less than 5.5% grain is kept in the straw after leaving the second cylinder at a specific MOG throughput of 9 kg/(s.m) as seen in Fig. 5. Through analysis of experiment with help of statistical software Origin, the function of integral of grain separation and remaining grain can be fitted by the following equations: S K1 = (1- a*b l )*100% R K1 = a*b l *100% (2) or by S K2 = (1 – A 1 e -l/t1 )*100% R K2 = A 1 e -l/t1 *100% (3) a, b, A 1 , t 1 are coefficients, which depend on the structural parameters of threshing unit (thresh gap, specific total throughput, feeding angle) (Tab. 1). Fig. 4. Definition of the grain masses in the classes 1 to 3 Fig. 5. Integral of grain separation of lab tests Grain separation by the concave and remaining grain of a multiple cylinders threshing system 82 Table 1. Coefficients of functions (S K1 , R K1 , S K2 , R K2 ) and the R-squared value Fig. 6. Coefficient a as a function of the total throughput with different concave clearance a)  = 50°; b)  = 60°; c)  = 70°; d) Average value of the coefficient a as a function of total throughput 170 175 180 185 190 195 200 205 210 5 6 7 8 9 10 specific grain and MOG throughput q [kg/(s.m)] Coefficient a [%] 20-14-10-8 20-16-12-8 22-18-14-10 sE/sA: DT1(mm) a) 175 180 185 190 195 200 205 210 5 6 7 8 9 10 Specific grain and MOG throughput q [kg/(s.m)] Coefficient a [%] 20-14-10-8 20-16-12-8 22-18-14-10 sE/sA: DT1(mm) b) c) d) 180 185 190 195 200 205 210 5 6 7 8 9 10 Specific grain and MOG throughput q [kg/(s.m)] Co effi cie nt a [% 20-14-10- 8 20-16-12- 8 22-18-14- 10 sE/sA: DT1(mm ) a = -5,11*(s.m/kg)*q + 228,26 [%] 180 185 190 195 200 205 210 5 6 7 8 9 10 Specific grain and MOG throughput q [kg/(s.m)] Co effi cie nt a [%] Le Minh Lu, Nguyen Xuan Thiet 83 Fig.7. Average value of the coefficient as a function of total throughput: a)-A 1 , b)-t 1 Fig. 8. Remaining grain as a function of specific Fig. 9. Remaining grain as a function of throughput at different feeding angles at concave throughput at different feeding clearance sE/sA_DT1_20-14-10-8; DT2_12/8 With the change of the adjusted parameters and the change of the throughput the coefficient b hardly changes. The coefficient a becomes smaller with constant feeding angles (50°, 60° and 70°) with more largely becoming concave clearance, Fig. 6. For the computation suggests computing an average value from all tests for the individual throughput. The following diagram, Fig. 6d) results for a. The coefficients A 1 , t 1 of the equations hangs on the test series of (, sE/sA, q). With bigger throughput the coefficient A 1 decreases, while the coefficient t 1 rises. In fig. 7a) and fig. 7b) are represented the average values of the coefficients A 1 and t 1 from all tests for the individual throughput. Fig. 8 and Fig. 9 show remaining grain that was not separated through the concaves as a function of the specific total throughput at different feeding angles. The remaining grain increases as expected with larger concave clearance and at higher throughput. It becomes clear that feeding angle and concave clearance mutually affect each other. Different feeding angles have low influence at the smallest concave clearance (Fig. 8). However, the a) b) A 1 = -4,9906q + 237,63 190 192 194 196 198 200 202 204 206 208 210 5 6 7 8 9 10 Cpecific grain and MOG throughput q [kg/(s.m)] Co effi cie nt A 1 [%] t1 = 16,091q + 253,18 340 350 360 370 380 390 400 410 5 6 7 8 9 10 Specific grain and MOG throughput q [kg/(s.m)] Co effi cie nt t1 Grain separation by the concave and remaining grain of a multiple cylinders threshing system 84 largest concave clearance causes recognizable differences in grain separation for the individual feeding angles (Fig. 9). The feeding angle  = 70° delivers the highest efficiency, which results in the conclusion that the feeding angle 70° causing nearly tangential feeding is very advantageous. There is still more than 94% of the grain separated at the concaves with large concave clearance and a specific grain and MOG throughput of 9 kg/(s•m). 4. CONCLUSION The new threshing system consists of two tangential rasp-bar cylinders, where the 1st rasp-bar cylinder is tangentially fed from a chain conveyer. Both cylinders are arranged one behind the other in the direction of the material-flow. For this arrangement the following advantages are proven in lab tests: With this threshing system the material is only tangentially accelerated. The crop experiences smaller forces of the rasp bars compared to conventional threshing systems. Broken grain and straw damage decreases. The first cylinder accelerates the material flow for the second cylinder, which causes higher grain separation in the second cylinder. The dwelling time of the material in the threshing system and the total separation surface of concaves increases compared to a conventional system resulting in an improvement of grain separation. The integral of grain separation and the remaining grain function depend at most of the structural parameters of the rasp-bar cylinders, concave length, feeding angles, concave clearance and specific total throughput. The integral of grain separation and the remaining grain function can be described with simple functions (2, 3). These functions approach the test results very well. Based on the tests we can conclude that such a threshing system contributes to the further increases in output, however, the concept of presents combines would have to be changed. It is an alternative to the hybrid system, since the specific power demand and the straw damage can be reduced. REFERENCES Arnold, R.E. and J.R. Lake (1964). Experiments with rasp bar threshing drums - Comparison of open and closed concaves - J.Agric.Engng.Res. 9 (3): pp 250-251. Beck, F.(1999). Simulation der Trennprozesse im Mähdrescher, Fortschritt- Berichte VDI- Reihe 14, Nr. 92, Dissertation Stuttgart Gieroba, J. and K. Dreszer (1992) Grain Separation in a Multidrum set for threshing and Separating - Riv.di Ing.Agr. XXII (1): pp 45-53. Huynh, V.M.; T. Powell, and J.N. Siddall (1982). Threshing and Separating Process - A Mathematical Model -Trans. of the ASAE 25 (1): pp 65-73. Kutzbach, H.D.(2000). Ansätze zur Simulation der Dresch- und Trennprozesse im Mähdrescher, Tangung Landtechnik 2000, S. 17-22. Wacker, P. (1995). Untersuchungen zum Dresch- und Trennvorgang von Getreide in einem Axialdreschwerk, Forschungsbericht Argrartechnik der Max- Eyth – Gesellschaft (MEG) Nr. 117, Dissertation. . evaluation of the concave length the integral of grain separation (S Ki ) and remaining grain (R Ki ) as defined in Eq. (1) and Fig. 4 was derived out of the measured grain masses gathered at the. length of the concave so reduce the remaining grain. This paper presents some main research results of grain separation by the concave, remaining grain and analyze the influence of the main. 2000). Through analyzing the results of lab tests with the help of the software Origin, two mathematical functions have been found. 2. MATERIALS AND METHODS The basic setup of the test stand