Device for preventing backflow of vacuum extract on screw extruder

Abstract

The invention relates to an improved mechanism of an auxiliary device on a screw extruder, in particular to a device for preventing the backflow of a vacuum extract on a screw extruder. A vacuum chamber communicated with a screw barrel on the bottom is arranged above the screw barrel close to a discharge end of the screw extruder, and a vacuum tube connecting port is arranged on the vacuum chamber; a heating chamber is arranged outside the vacuum chamber, a heating plate is installed on the inner wall of the heating chamber, and a heating resistor is arranged in the heating plate; and the heating resistor is connected with a heating power source through a temperature control instrument, a probe of the temperature control instrument stretches into the heating chamber, and a heating chamber opening corresponding to the position of the vacuum tube connecting port is arranged on the heating chamber. The invention not only can vacuum-extract air and small-molecular impurities in the screw barrel of the screw extruder for separation, but also can avoid the condensation and the backflow of the extract in the vacuum chamber to fall into the screw barrel of the extruder once again to influence product quality. The invention has simple structure and obvious effect and is convenient to use.

Description

technical field [0001] The invention relates to an improved mechanism of an auxiliary device on a plastic extruder, in particular to a device for preventing the backflow of vacuum extracts on a screw extruder. Background technique [0002] The screw extruder is a device used to extrude and granulate modified plastics. Its basic working principle is to use the rotation of the screw in the heating barrel to realize the conveying, propulsion, melting and homogenization of the material and the output of granulation. The screw generally follows the sequence Divided into the following 5 sections with different functions: conveying section, melting section, mixing section, exhaust section, homogenizing section, among them, the conveying section corresponds to the feeding end of the screw barrel, which is used to transport materials and prevent overflow; melting The material is fully melted and homogenized through heat transfer and frictional shearing in the section; the mixing sect...

AI Technical Summary

Problems solved by technology

[0004] This vacuum extraction method can effectively separate gas and small molecular substances, but it is prone to a problem: after the gas and small molecular substances are extracted from the screw barrel, they condense into liquid before they leave the vacuum chamber through the vacuum tube. Under the action of gravity, the flow back from the bottom of the vacuum chamber falls back into the screw barrel of the extruder, resulting in incomplete separation of impurities, resulting in discoloration of the product, or other quality problems

[0005] In order to change the condensation and reflux of the vacuum extract, experts in the industry have taken various measures, such as setting a vacuum chamber on the side of the screw barrel, the side of the vacuum chamber communicates with the screw barrel, and the vacuum tube is set at the bottom of the vacuum chamber, so that even If the vacuum extract is condensed in the vacuum chamber, it will only be discharged by the vacuum tube at the bottom of the vacuum chamber under the action of gravity, and no backflow will occur. However, the setting method of the side vacuum has created new problems: the screw extruder stops or feeds When the material changes, due to the change of the pressure inside the screw barrel, the viscous material that fills the gap between the screw barrel and the screw will flow into the vacuum chamber from the screw barrel of the extruder, thereby blocking the vacuum tube and causing the exhaust system to fail to operate normally.

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