EXTRUDER FOR PROCESSING POLYMER MELTS

Abstract

An extruder containing a housing having a flow channel for a melt and a perforated plate delimiting the flow channel on the outlet side, where the perforated plate has at least two through-flow areas spaced apart from one another, each through-flow area contains at least one through-flow opening, and the perforated plate is furthermore mounted in a changing device, where the changing device has guide elements, in which the perforated plate can be moved substantially perpendicularly to the flow channel, and the extruder, directly ahead of the perforated plate when viewed in the direction of flow of the melt, has an inlet flow cone, which is structurally separate from the perforated plate, thus allowing the through-flow areas of the perforated plate to be moved relative to the inlet flow cone.

Claims

1. An extruder comprising a housing having a flow channel for a melt and a perforated plate delimiting the flow channel on the outlet side, wherein the perforated plate has at least two through-flow areas spaced apart from one another, wherein each through-flow area contains at least one through-flow opening, and the perforated plate is furthermore mounted in a changing device, wherein the changing device has guide elements, in which the perforated plate can be moved substantially perpendicularly to the flow channel, and the extruder, directly ahead of the perforated plate, when viewed in the direction of the flow of the melt, has an inlet flow cone, which is structurally separate from the perforated plate, thus allowing the through-flow areas of the perforated plate to be moved relative to the inlet flow cone.

2. The extruder as claimed in claim 1, wherein the spacing between the through-flow areas of the perforated plate is dimensioned in such a way that, when one through-flow area is positioned at the outlet of the flow channel, at least one other through-flow area is situated outside the housing of the extruder.

3. (canceled).

4. The extruder as claimed in claim 1, wherein the changing device has a plate which is first and a plate which is second when viewed in the direction of flow of the melt, both of which have an internal opening through which the melt can flow, and wherein the first plate and/or the second plate have/has a recess, in which the perforated plate is movably mounted.

5. The extruder as claimed in claim 1, further comprising an actuator for moving the perforated plate, at least one sensor for detecting a pressure in the flow channel and a control module, wherein the control module is designed in such a way that the perforated plate is moved with the aid of the actuator when a predetermined critical value for the pressure or for a pressure difference is reached.

Description

[0037] The invention is explained in greater detail below with reference to the drawing. The drawing should be understood as a schematic illustration. It does not represent a restriction of the invention, in respect of specific dimensions or variant embodiments for example.

LIST OF REFERENCE SIGNS USED

[0038] 1 . . . extruder outlet [0039] 2 . . . flow channel [0040] 3 . . . inlet flow cone [0041] 4 . . . inlet flow element [0042] 5 . . . actuator for inlet flow element [0043] 6 . . . perforated plate [0044] 7 . . . through-flow area [0045] 8 . . . guide element [0046] 9 . . . first plate [0047] 10 . . . second plate [0048] 11 . . . actuator for changing device [0049] 12 . . . seal [0050] 13 . . . granulating tool

[0051] A preferred embodiment of the invention is reproduced schematically in exploded view in FIG. 1. Of the extruder, only the extruder outlet 1 is shown. The direction of flow of the melt is from left to right. A first plate 9 and a second plate 10 are flanged to the outlet end of the extruder and connected firmly to the extruder.

[0052] Between the upper and lower end, the second plate 10 has an internal recess 8, in which a perforated plate 6 is movably mounted. The perforated plate 6 comprises two through-flow areas 7, which both contain a multiplicity of through-flow openings. The outer contour of the through-flow areas 7 (envelope around the through-flow openings) is in each case circular and corresponds in cross section to the internal cross section of the flow channel 2 at this point. To move the perforated plate 6, an actuator 11 is provided, which can move the perforated plate substantially perpendicularly to the flow channel 2 by means of a linear motion.

[0053] Arranged between the extruder outlet 1 and the first plate 9 is an inlet flow element 4, which can be rotated through a predetermined angle with the aid of an actuator 5. For specific embodiments and advantages of this inlet flow element 4, attention is drawn to the parallel German Patent Application 102015226512.9.

[0054] To avoid the melt escaping at an unwanted location, sealing elements 12 are provided between the extruder outlet 1, the inlet flow cone 3, the perforated plate 6 and the second plate 10.

[0055] A granulating tool 13 is provided at the outlet end of the apparatus, resting on the perforated plate 6 and cutting the melt strands emerging through the through-flow openings into small granules by means of a rotary motion.