DEVELOPMENT OF THRESHING SYSTEM IN COMBINE HARVESTER FOR IMPROVING OF ITS PERFORMANCE EFFICIENCY IN RICE THRESHING

Abstract

The combine (Class Crop Tiger) which was used in the present study is middle size (2.10 m cutting width). The axial flow drum was used in this combine. Separation wings were parallel with its axis. So, some improvements could be added to the axial-flow threshing/separating drum to improve the straw flow to reduce blockage, loss and to improve field efficiency and grain yield. So, improving the performance of combine machines during the harvesting operation of cereal crops is important to minimize both grain losses and operational costs. The main experiments were carried out at Ahmed Ramie Farm, Etai Al Barod, El-Behera Governorate, in order to compare four different types of threshing and separation drums of combine. The experiments were conducted in productive rice crop, variety (Giza 171) in an area of about 4.10 feddans. Specifications of threshing and separation drum before and after development: 1- Design and fabricate three serrated agitator ledge (15, 10 and 7 teeth), so that the passing crop and separation will be easy. 2- The length of threshing and separation is 180 cm, it consists three parts, the first part of the threshing section length 57.5 cm, the second part of the separation section length 90.5 cm, it change the separation section length to 110.5 cm to increase the grain separation efficiency and the third part of the straw exit section length to 22 cm. 3- The thickness of the separation vane to be 5nm instead of 3.5 min. 4- Using steel 60 to overcome the wear of vanes during the separation operation. Using three levels of cylinder speed as 500, 630 and 803 rpm (17.0, 21.4 and 27.3 m/s, adjusting the cylinder-concave clearance by using three levels of clearance namely 12.5/5.5, 13/6 and 16/7 n, and using two levels of feeding rate 2000 and 3000 kg/h. The results showed that: 1- The total grain losses decreased by decreasing both of the feed, rate, operating forward speed, threshing drum speed and the cylinder-concave clearance. 2- The threshing efficiency increased by decreasing the feed rate and operating forward speed, and it decreased by decreasing threshing drum speed, increasing the cylinder-concave clearance. 3- The grain quality increased by decreasing the feed rate, operating forward speed and threshing drum speed, and it decreased by decreasing the cylinder-concave clearance. 4- The cleaning efficiency increased by decreasing the feed rate, operating forward speed and threshing drum speed, and it decreased by increasing the cylinder-concave clearance. 5- The highest values of the actual field capacity at the feed rate 200kg/h/operating forward speed of 1.22 km/h/grain moisture content 21%, threshing drum speed of 500 rpm (17 m/s) and the cylinder-concave clearance (C1) of 12.5/5.5mm, was found to be as the developed rotor 7 teeth (0.489 fed/h), the develop rotor 10 teeth (0.473 fed./h), the developed rotor 15 teeth (0.460 fed./h) and the original rotor 15 teeth (0.42g fed./h). 6- The least values of the required energy at the feed rate of 2000 kg/h, operating forward speed of 1.22 km/h/grain moisture content of 21%, threshing drum speed of 500 rpm (17 m/s) and the cylinder-cancer clearance (C1) of 12.5/5.5 mm, was found to be as the developed rotor 7 teeth (30.186 kw.h/fed.), the developed rotor 10 teeth (34.600 kw.h/fed.), the developed rotor 15 teeth (41.159 kw.h/fed.) and the original rotor 15 teeth (51.613 kw.h/fed.). 7- The least values of the operating costs at the feed rate of 2000 kg/h, operating forward speed of 1.22 km/h/grain moisture content of 21%, threshing drum speed of 500 rpm (17 m/s) and the cylinder. Concave clearance (c1) of 12.5/5.5 mm, was found to be as the developed rotor 7 teeth (223.50 LE/fed.), the developed rotor 10 teeth (240.50 LE/fed.), the developed rotor 15 teeth (270.25 LE/Fed.) and the original rotor 15 teeth (314.75 LE/fed.). 8- The better results were reached under operating conditions was found to be as threshing drum speed of 500 rpm, feed rate of 2000 kg/h, operating forward speed of 1.22 km/h, cylinder-concave clearance of C, (12.5/5.5 mm) at grain moisture content of 21% was found to be as the developed rotor (7 teeth), whereas the total grain losses of 1.68%, required energy of 30.186 kw.h/fed., operating costs of 223.50 LE, fed., threshing efficiency of 99.34%, separation efficiency of 99.27% and, cleaning efficiency of 99.71%.