Screw rods for PIN-type three-screw extruder

Abstract

The invention relates to a screw rod structure, in particular to screw rods used on a PIN-type three-screw extruder. Each screw rod of the extruder is composed of a screw rod mandrel (2) and a threaded element (1) sheathed on the screw rod mandrel. Threaded elements (1) of the three screw rods are meshed with each other in a conjugate manner, and the shapes of the meshed parts of the threaded elements (1) are the same. The semi-diameter of an outer circle formed by the rotating of each threaded element (1) is a, the semi-diameter of an inner circle is b, and a/b is larger than 1.3 and smaller than 2.15. By adopting the above technical scheme, an overlapped zone of motion traces of the outer diameter of the meshed threaded elements on the three screw rods becomes larger and larger along with the increasing of the groove depth ratio; even if the three screw rods cause a meshing enclosed zone to disappear due to improper design of the tooth shape, materials in a central material zone can carry out forced flowing exchange with external materials and actively participate in plasticizing and milling, thereby improving the performance of finished materials.

Description

technical field [0001] The invention relates to a screw structure, in particular to a screw used in a pin-shaped three-screw extruder. Background technique [0002] At present, in the field of plastic compounding, parallel twin-screw extruders are commonly used, and its transmission is a parallel two-axis output. With the continuous development of the modern plastic industry, especially the wide application of high-filling and high-dispersion materials and the requirements for low energy consumption, rubber and plastic processing equipment is developing in the direction of diversification and multi-screw. Compared with the traditional twin-screw extrusion system, the three-screw extrusion system has better splitting effect and more times of shearing, that is, better distribution mixing and dispersion mixing, and has a larger exhaust interface area, which is more conducive to exhaust operation , which minimizes the impact of exhaust on output and has the advantages of lower ...

AI Technical Summary

Problems solved by technology

When the three-line threaded element with common groove depth ratio is engaged in conjugate engagement, a central closed area will appear. Since the outer circle formed by the threaded element during the rotating engagement process cannot cover the closed area, the material cannot be affected by the thread in it. The shearing and extrusion of the components, therefore, the material in the central area is directly extruded, and rarely exchanges with the material flow outside the area, and the mixing effect is poor, which directly affects the performance of the finished material

In addition, the pressure building mode of the traditional three-screw output terminal adopts a large number of counter-rotating meshing blocks. When the pressure is built up, the shear is too strong, causing the material to age and decompose or the molecular chain to be shortened, and the performance of the finished material is reduced.

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