Three Screw Extruder Machine Screw Element And Mixed Mechanism

There are increasingly high requirements to the pulverization and dispersion of various compositions of material in processing as well as the mixing state and configuration of the resultant mixture along with the rapid development in modification of the polymer, correspondingly superior mixing equipments are required for the purposes of high quality, high efficiency and low power consumption. Accordingly, a new type triple screw extruder has been completed the research and development by our institute.The triple screw extruder has an arrangement of axes of three screws as a inverted equilateral triangle and the screws of identical diameter parallel each other and all in the initiative rotation with same direction. Obviously though it has only one more screw in comparison with co-rotating twin-screw extruder, but it results in many differences such as screw configuration, curve design and operating performance of the machine, etc. It is of great importance to the research and development and the extrusion theory of the triple screw extruder to make a thorough study of the plasticzing system of it. The structure and mechanism of the new equipment have been studied chiefly in this thesis.The studies in the thesis centered on the following:The elementary analysis on the triple screw geometry includes basic structure, geometry configuration and the relationship between geometric parameter and performance. For revealing geometric parameter and its effect, it is started with the calculation of the polynomial coefficient, then plotted the correlation curve to predigest the complex relation of the.function as simple curve and to visualize even more the analysis determination and valuation.Based on the classification of mixing, the effective factor, the conception of mixing quality ,a thorough research is made on the mixing performance of the triple screw extruder and the special character of flow on the central region is analyzed objectively and rationally through the calculation ofgeometric parameter.The mathematical model of normal modification of the screw element is derived indetail and the function expression of curve surface of modified screw is given. Based on then, the normal modification software is compiled by the C, VC 6.0 and VisualLisp languages, and the accuracy and reliability of the calculation and convenience of utilization are verified by comparing with other modification method.All screw elements are redesigned using the normal modification software which is compiled the C,VC 6.0 and VisualLisp languages, causing the screw curves in the axial direction more accurate and more precise in comparison with other designs using the method of MDT(Mechanical Desktop) modification and offering new screw element combinations tending more reasonable.