Buhler Ag

Jürgen Schweikle

Andreas Christel

Federico Innerebner

Achim-Phillipp Sturm

Achim Philipp Sturm

Achim-Philipp Sturm

The method of degassing is performed in a ring extruder wherein at least one process chamber is provided with at least one degassing opening. The radius R of the conveyor element in the degassing zone is smaller by &#x394;R than the full radius Rv of the conveyor element required for the mutual stripping of adhering product in a closely intermeshing screw operation with adjacent conveyor elements.

Method of degassing a flowable mass in a ring extruder

The invention relates to a multiple-screw extruder that comprises a first process chamber () and a second process chamber (). In the degassing zones of said extruder, at least the first process chamber is provided with at least one degassing opening. The radius R of the conveyor element in the degassing zones, in at least one conveyor element () of at least one screw () configured as a passage screw, in a subsection configured as a passage subsection (), along the peripheral direction of the at least one conveyor element () is by &#x394;R smaller than the full radius Rv of the conveyor element () required for the mutual stripping of adhering product in a closely intermeshing screw operation with die adjacent conveyor elements () of adjacent conventional screws (). The invention also relates to a method for degassing viscous or elasticoviscous flowable masses in such a multi-screw extruder having several process chambers, the respective process chambers communicating by means of a connecting opening.

Degassing of flowable masses in a multiple-screw extruder

The invention relates to a multi-shaft extruder for the continuous treatment and/or processing of bulk material, especially a powdery, granular or flocculent product, comprising a plurality of shafts () which are arranged in a crown-like manner in a cavity () of an extruder housing (), said shafts extending parallel to the axial direction (A) of the extruder and forming an inner processing chamber () inside the crown, and an outer processing chamber () outside the crown. Each shaft carries a number of axially successive processing elements (), at least part of the same being elements () having a transporting effect, and with which adjacent shafts engage in a sealed manner at least in partial regions. At least one transporting endless screw element () comprising at least one transporting screw thread () is placed in the region of the supply opening () in the extruder housing (), and does not engage in a sealing manner in at least one partial region along the axial direction (A).

Multi-screw extruder

The invention relates to a multi-screw extruder for the continuous treatment and/or processing of a bulk material, especially a product in powder, granular or flake form, comprising several shafts () which are arranged in a ring shape in a cavity () of an extruder housing () and which extend parallel to the axial direction (A) of the extruder. The extruder housing () is provided with axially parallel, concave segments () of a circle on the radially inner () and radially outer () surfaces of the cavity (). These circle segments act as a guide for the axially parallel shafts () with their processing elements () on the inside () or on the outside () of the shaft ring (, . . . ). The inventive improvement lies in the radial extension of the axial partial area of the cavity () containing the shafts (), which is located in the area of the feed opening (), this radial extension () extending along part of the shaft ring (, . . . ) in the peripheral direction (U) of the same.

Ring extruder feed

A method for processing a polycondensate to give a granulate formed as pellets is disclosed, whereby the polycondensate is fused in the course of the method and then later resolidified. In an exemplary method, a total time during which the temperature of the polycondensate is above the melting point thereof is less than about 60 seconds. This method can be carried out by a multi-shaft extruder, whereby the degrassing and/or drying of the polycondensate in the solid state occurs at a pressure below atmospheric pressure and/or with addition of an inert gas. The time period, during which the polycondensate remains in the extruder, after being melted therein, amounts to, for example, less than about 15 seconds.

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Niederhelfenschwil, Switzerland

Jürgen Schweikle