Views: 46 Author: Site Editor Publish Time: 2021-10-29 Origin: Site
A screw extruder is a machine that can concentrate a series of chemical basic unit processes, such as solid conveying, pressurizing, melting, exhausting, dehumidifying, melting conveying, and pumping out physical processes on the screw in the extruder. According to the number of screws, extruders can be divided into single-screw extruders and twin-screw extruders. What is the difference between the two?
Here is the content list:
l Material delivery method
l Material flow velocity field
l Technical conditions
In a single-screw extruder, friction drag is in the solid conveying section, and viscous drag in the melt conveying section. The friction properties of solid materials and the viscosity of molten materials determine the conveying behavior. If the friction performance of some materials is poor, if the feeding problem is not solved, it will be more difficult to feed the materials to the single-screw extruder. In twin-screw extruders, especially intermeshing twin-screw extruders, the conveying of materials is positive displacement transmission to some extent, and the degree of positive displacement depends on the screw of one screw of the twin-screw extruder. The proximity of the edge to the opposite groove of the other screw. The screw geometry of the tightly meshing counter-rotating twin-screw extruder can obtain a high degree of positive displacement conveying characteristics.
At present, the flow velocity distribution of the material in the single-screw extruder has been described quite clearly, while the flow velocity distribution of the material in the twin-screw extruder is quite complicated and difficult to describe. Many researchers just analyze the flow velocity field of the material without considering the material flow in the meshing zone, but these analysis results are very different from the actual situation. Since the twin-screw extruder and mixing characteristics of the overall behavior of the machine depends on the meshing zone leakage flow occurs, and therefore the engagement region of the flow is very complex. The complex flow spectrum of the material in the twin-screw extruder macroscopically shows the advantages that the single-screw extruder can’t match, for example, sufficient mixing, good heat transfer, large melting ability, strong exhaust ability and good temperature control of the material, etc.
The single-screw extruder is not technically as mature as the twin-screw extruder. It does not have industry standards or national standards. If the single-screw extruder fails, its bail right belongs to the manufacturer, and the twin-screw extruder must comply with national standards and industry standards. The single-screw extruder is theoretically advanced than the twin-screw extruder, but because the material of the single-screw is resin material, it is easy to wear when the star wheel and the screw are in meshing operation. The high temperature of the press and shutdown conditions, so the raw materials and processing technology and accuracy cannot guarantee that it is theoretically advanced than the twin-screw extruder.
Nanjing Haisi Extrusion Equipment Co., Ltd. is a mature extrusion technology company, designing and manufacturing world-class extruder equipment, and our company’s mission is to provide the world with the highest quality and reliable extrusion machine. If you are interested in the extruder, please feel free to contact us.
