Extruder conical counter-rotating

Fig. 13.1. Different types of extruders, a) single screw b) co-kneader c) non-intermeshing, mixing mode d) nonintermeshing, transport mode e) counter-rotating, closely intermeshing f) co-rotating, closely intermeshing g) conical counter-rotating h) self-wiping, co-rotating.

Screws and barrels for conical counter rotating extruders are significantly different from the parallel... 

Most of the compounds were extrusion compounded in a conical, partially intermeshing, counter rotating twin screw extruder (Haake Reomix TW-lOO). The extruder speed was set at 50 rpm and the barrel temperature profile was set to produce a melt temperature of 260°C at the die. Samples were injection molded in a 31.8 MT Battenfeld press with a 59 cc shot size. Where noted, samples were compounded in a 60 cc Brabender internal mixer and compression molded. 

The market for counter-rotating twin-screw (TS) extruders is basically dominated by two designs. One has cylindrical screws called parallel TS extruder and the other TS extruder is fitted with conical screws. Performancewise, the superiority of the conical principle to parallel does not only appear in the theoretical comparison, but in practice as confirmed by users. Flexibility of conical turns out an extrudate of consistent quality at both low and high output rates which are not sensitive to raw material fluctuations. It appears that the parallel have reached their efficiency limit unless a means of drastically increasing the... 

Counter-rotating twin screw extruders are used almost exclusively for the production of uPVC pipes, profiles and sheet because they treat material more gently than single screws. Parallel screw and conical twin screw extruders are compared. Cincinnati Milacron Austria introduced its Argos parallel twin screw extruders last year. These machines are intended to complement the company s Titan conical screw range. Coextrusion of foamed core pipes is also described. 

Twin-screw extruders can be co- or counter-rotating, intermeshing or tangential, cylindrical or conical. Co-rotating screws are very efficient mixers for high viscosity fluids due to the axially and cross-wise open... 

Counter-rotating extruders Conical extruders for profile extrusion Parallel extruders for profile extrusion High speed extruders for compounding... 

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