Theoretical Research Of The Structure Of High-Viscosity Gear Pump

Energy shortage is the main scourge of modern world. As a result, people are trying their best to develop new equipment which are the most energy-saving and products with the highest precision are their preferences. Under this condition, melt pump assisted extruder flourished. With their particular merits such as easy pressure raising and flow fluctuation eliminating effect, melt pumps are used in the manufacturing of sheet, cast, blown film, pipes and so on. In most highly developed countries such as America, Japan and Germany, the research and application of melt pump in polymer processing have been made rapid progress. But in China, its application is still on its initial stage.In this paper, the properties and principles of gear pump are described in this paper and the mathematical models of melt lubrication and viscous seal were constructed.The first characteristic of this paper is that the theory of melt transferring in single-screw extrusion is applied into the modeling of dynamic viscous seal and a simple equation for calculating the structure of the dynamic seal is given, which can not be found in the documents available.Another characteristic is that the curve of lubrication provided by this paper is a new technique for validating the reliability of the design of melt pump. Because of the complication of the flow of lubrication medium, especially the non-Newtonian high polymer melt, the flow of melt in the bearing is analyzed with three dimensional finite element method (FEM) and graphs of relations of the pump structures operational condition and the materials processed in the lubrication of melt pump are given, which have been verified practical by the experiments with the melt pump being used in the second chemical factory of Beijing Yanshan petrochemical company.The third characteristic is that by analyzing the factors of influence on the volume efficiency, the paper summed up methods and calculated one of them through FEM and showed the feasibility of this method.Finally, the paper provides a set of integrated theory, which can be safely based on by future research of high viscous melt pump.