Intermeshing screws

Holo-flite intermeshed screws for circuloting cooling Of heoting fluid... 

In addition to single screw extruders, there are twin and multiscrew extruders that perform essentially the same functions, but with additional benefits. Among these, the intermeshing twin screw extruders are the most important ones. They are used primarily for heat-sensitive resins (such as PVC), which are difficult to process. The intermeshing screws create a relative motion of one flight in another, such that it acts... 

Fig. 6.47 Two intermeshing screws with the channel segments of one of the screws filled with silicone rubber, reproducing the shape of the channel segments. Two segments are pulled out, one retaining the original curved shape and the other flattened out into a trapezoidal channel.

Counterrotating intermeshing screws provide a dispersive milling action between the screws and behave like a positive displacement device with the ability to generate pressure more efficiently than any other extruder. 

Hole- tiite intermeshed screws for circulating cooling or heating fluid... 

The tasks of polymer compounding can be the mixing of the polymer with additives and fillers (such as glass fibers), and the degassing of volatile components such as monomers. It can even mean to carry out chemical reactions in the extruder. Usually extruders with two intermeshing screws, so called co-rotating twin screw extruders, are used. 

VI. Co-rotating partially intermeshing, L C-open Vn. Co-rotating, fully intermeshing, screw ... 

With intermeshing screws, the relative motion of the flight of one screw inside the channel of the other acts as a wedge that pushes material from... 

In contrast, in twin-screw extruders with intermeshing screws the relative motion of the flight of one screw inside the channel of the other pushes the material forward almost as if the machine were a positive displacement gear pump which conveys the material with very low friction. In twin-screw extruders, heat is therefore controlled independently from an outside source and is not influenced by screw speed. This fact becomes especially important when processing a heat-sensitive plastic like PVC. 

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