Experiment Study On The Cleaning System Of Micro Portable Grain Combine Harvester

There are a large number of hill in our country, where rice,wheat and other grains are planted. The farmland of these area is characterized by small plots and difficult to go through, which restricts using of the large grain combine harvester. Micro grain combine harvester is put forward a new type of grain combine harvester for hilly need. It requirements that the machine has samll structure of working parts, light weight, easy to walk and go through.Cleaning is an important content of grain harvest. To simplify the structure of cleaning system and lose weight are the basic requirements to micro grain combine harvester cleaning system. Based on free cutting, micro grain combine harvester which uses cyclone separating cleaning system with double winnowers, has characteristics such as a simple structure, light weight, operating easily, etc. Cleaning materials can be in two mutually perpendicular plane finished for conveyor and cleaning operation. But field tests shows that under the existing designed parameters, cleaning ability of the cleaning system with double winnower cyclone separating is limited. When big feeding, it is easy to appear system congestion, high cleaning loss rate.This study regarded cyclone separating cleaning system with double winnowers which were used on micro grain combine harvester as the research object. The test of screw conveyor on the influence law of material conveying, showed that the speed of screw conveyor above 500 r/min, it could satisfy the requirement of the test material conveying; Through research of the two pipes airflow without the material, determined the critical curve of static pressure in the two pipes; The test of cleaning performance, selecting rotation speed of the first winnowing n1, rotation speed of the second winnowing n2 and rotation speed of fan n3 as test factors, the cleaning rate, cleaning loss rate and grain breakage rate were selected as the indexes. It determined the critical speed of the working parts: n1=600r/min、900r/min≤ n2 ≤ 1400 r/min、2800 r/min ≤ n3 ≤ 3400 r/min. Selecting the cleaning rate and cleaning loss rate as the indexes, tests on the rotation angle and offset distance, determined the rotation angle and offset distance were 30°,30 mm respectively when the cleaning effect is good. Selecting rotation speed of the second winnowing and rotation speed of fan as test factors, the grain cleaning rate, cleaning loss rate and grain breakage rate were selected as the indexes. The better parameter combinations, that rotation speed of the second winnowing and rotation speed of fan were respectively 1177r/min, 2948r/min, were obtained through the weighted optimization method. Under the parameters, the cleaning loss rate was 98.17%, 0.051%. With optimized parameters, the validation test of the result was done, as well as tests of the cleaning system for adaption to the feed rate and material status. respectively. The results showed that: when amount of cleaning feeding was not more than 0.12 kg/s, impurity rate less than 30%, the grain moisture content less than 13.6%, chaff moisture content less than 28.1%, the grain cleaning rate, was above 98%, cleaning loss rate could be controlled within 0.062%. The field test of installed harvester showed that the cleaning system had worked smoothly and performed stably.