Research And Development Of The Polymer Melt Pump With The Transporting System

The polymer melt pump with transporting system is a device used to transport the molten polymer, installed between the screw extruder and the die. Its outstanding characteristic is that the pressure of the outlet nearly can't be influence on the pressure fluctuation of the inlet, and provide the uniform and steady molten polymer for the die. As the pressurize device, the melt pump has been applied extensively in field of the precision extrusion.In this paper, the working theory and features of the melt pump are introduced firstly, the characteristic of the flow, the computation of the energy efficiency and the total efficiency are analyzed deeply, and the main technical parameters and how to choose are discussed, such as volume flow, working temperature, pressure and torque.The design principles of the melt pump are introduced roundly, and a new design program is summarized, including the design of the gear, rotation speed, lubrication system, seal structure, pump body, heating system, driving system and control system. The design of the lubrication system is the technical difficulty for the melt pump. In order not to pollute the molten polymer, the common lubrication oil can't be used, but the molten polymer instead. In this paper, the mechanism of realizing the self lubrication is analyzed deeply, and the load of the bear is supported by the hydrodynamic pressure. Therefore, the melt viscosity, eccentric ratio and rotation speed, in other words, the hydrodynamic pressure is dependent on the melt viscosity, eccentric ratio of the bear and ration speed, this in turn effect the forming of the lubrication film. According to analyze the distribution law of the parameters by polyflow software, such as pressure, velocity, shear rate and the melt viscosity, the effect of melt viscosity, eccentric ratio and rotation on the hydrodynamic pressure are discussed, and a series of load curves are got, which provide the theory basis for the design of the lubrication structure of the melt pump.According to the design program and the practical application, a prototype of the melt pump is designed.