Development Of Distributing Device For Large Vertical Dryer

Compared with horizontal drying equipment, the large vertical dryer has high drying efficiency and efficient energy utilization, covers less area, easier to continuous processing. It has wide application prospects in the drying of rice, wheat, feed and so on. The problem was that the vertical dryer’s stock supporting plate area is large, the drying effect would be directly impacted by the material distributing uniformity on the plate and thus affect the uniformity of the moisture content of the product and the drying process efficiency. Therefore, the development of distributing device to the large vertical dryer had great importance for the research and application of vertical dryer. A distributing device was designed to realize the uniformity and in this paper some relevant explore and experimental research were been done to achieve the goal.A scheme that the distributing device worked on large and static distributing areas should be consisted of revolving distributing and reciprocating raking was been found after analysing the existing distributing machine at home and abroad. On the basis, the motive power and transmission plan of this distributing device were determined. The modern design methods and AUTOCAD, CAXA, Pro/E or other mechanical design software were utilized in this thesis to provide theoretical analysis and optimal design to the bracket, inlet hopper, rotary distributor mechanism, reciprocating raking mechanism, stock supporting plate and its bindiny mechanism and electrical control system. Finally, the prototype was manufactured with the design drawings.As granulated feed for test materials, single factor experiment had been used to analyze the influence of device primary structure and technological parameters with material surface flatness for index. MATLAB software had been put to use to simulate the material surface condition according to the measuring points and also got the distribution of material thickness. The distributing plate revolving speed had significant effect to the material surface flatness under this test condition (P<0.01). The coefficient of variation was maximum at7.551%when the distributing plate revolving speed was35r/min, and was minimum at7.2%when the distributing plate revolving speed was50r/min. To the same, the distance of distributing plate also had significant effect to the material surface flatness (P<0.01), and the coefficient of variation was minimum at7.76%when the distance of distributing plate was680mm. As to the reciprocating raking mechanism, its reciprocating frequency was insignificant to the material surface flatness when it worked (P<0.01). The result also showed that the installation angle of blade had significant effect to the material surface flatness under this test condition (P<0.01). The coefficient of variation was maximum when the blade installation angle was0, and was minimum at7.7%when the angle was30°.On the basis of the device primary structure and technological parameters’single factor experiment, as for distributing plate revolving speed two levels45r/min and50r/min, the blade installation angle30°and45°, the distributing plate distance680mm and740mm were been chosen for the machine performance test. The results of variance analysis showed that the distributing plate revolving speed (A) and the distributing plate distance (C) had significant effect to material thickness coefficient variation (P<0.01). Interaction B×C, the blade installation angle (B) and interaction A×C had less effect (P<0.05). The distributing uniformity requirement had been effectively satisfied when the distributing plate revolving speed was50r/min, the distributing plate distance was680mm and the blade installation angle was45°, meanwhile, the coefficient of variation was minimum and it was7.551%.