U.c. Industries, Inc.

Owens Corning

Kilian K Mendel

James R Cisar

An extrusion die and flow control method incorporates a flow control in the form of a flow diverter which extends transversely across the flow path. The diverter forms part of a window upstream of the die lips and provides a slight tapering enlargement which may be moved along the window across the flow path from one side to the other or preferably, from the center symmetrically outwardly, or vice versa, to divert flow from the center proportionally to the edges without changing the total cross sectional area of the window. The window is formed by a pair of axially rotatable cylindrical bars recessed in the die body which each have a flat forming the enlargement. In the preferred form the flat is helical. The helical flats are opposed or matched so that as the bars contra-rotate synchronously the enlargement will move across the window. Where the movement is symmetrical from the center or axis to each transverse edge and vice versa, the helical matching flats on each bar turn in opposite directions on each end of the middle of each bar. Where the enlargement simply moves from one transverse end of the window to the other the turn of the helix of each flat is the same from end to end of the bar, although for each of the pair, in the opposite direction. Movement of the enlargement across the flow path is obtained by axial rotation of the bar. Tandem pairs of bars may be used separately or in conjunction with each other, and may have axially inclined flats.

Extrusion die and method of controlling flow through the die

A foam extrusion apparatus and method in which extrudate is extruded into a sealed chamber which may be subjected to pressure variation such as a vacuum with the controlled shaping of the plastic being obtained by power driven rolls within the chamber downstream of the die. Because of the harsh environmental conditions within the chamber it is desirable that the shaping or forming rolls be driven by an externally powered source which will therefore be not subject to the pressure, vacuum, or other deliterious conditions found within the chamber. Moreover, because of the external position of the drive with regard to the chamber, the entire system need not then be shut down in order to open the chamber and make the required adjustments or repairs. The chamber is preferably the upper end of a barometric leg into which the extrudate passes. The upper end of the chamber is closed by one or more bulkheads which are movable toward and away from the upper end of the chamber. The present invention utilizes DC drive motors on the exterior of the bulkheads and of course the chamber to drive the shaping rolls which are downstream of the die. With this arrangement, both torque and speed may be closely controlled and of course the chamber does not require to be opened to make adjustments, replacements or repairs to the power system.

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Wadsworth, OH, United States of America

Kilian K Mendel