Study On Tandem Extrusion System Of Single Screw-Melt Pump

In this paper the extrusion equipment that is composed of single-screw extruder and melt pump is defined as "Tandem Extrusion System of Single Screw—Melt Pump", or simplified as "SP system".In the dissertation, based on the former research by other predecessors and through academic analyses and experiments, the working principle and the performance characteristics of SP system are discussed systemically. It points out that the predominant performance of the extruder can be upgraded and achieved through the proper combination of single-screw extruder with melt pump. In another words, Tandem Extrusion System of Single Screw—Melt Pump is a kind of extrusion equipment with high performance characteristics. Compared with the common single-screw extruder, it has obvious predominance on melt mixing, plasticing quality, output, flow uniformity, degassing extrusion stability, wide applicability and outstanding operating capability.One characteristics of the SP system is flow stability. In the paper studied on the throughput characteristics, output formula, throughput -pressure curve and workaround are depicted. It indicates that the main factors that influence SP system flow stability are the speed, configuration, pressure drop and material viscosity. It also indicates that flow stability is determined by the throughput balance between single screw extruder and melt pump. Factors that influence flow stability and the approach to achieve it are discussed. Another characteristics of SP system is high output and melt plasticing ability. In order to meet the high output requirements of the extrusion screw in SP system, the concept of "SP screw", design ideology and configuration parameter feature are indicted. Metering zone of SP screw is analyzed through a finite element package, ANSYS. A series extrusion experiments were carried out to confirm the coherence between the theoretical analyses and experiment result.Research and conclusion of this dissertation will give some guidance in the application and equipment R&D work of SP system. Meanwhile, it is also valuable and helpful to other applications of melt pump extrusion technique in plastic extrusion-molding area.