Patent Number: 6,168,411

Title: Polymer filtration method and apparatus

Abstract: The present invention includes a filtration apparatus for an injection molding machine where the injection molding machine includes a screw housed within a bore for generating molten polymer. A tip member extends axially from the screw. The tip member has radially extending upstream and downstream flanges positioned axially apart from each other. A filter encircles the tip member and is capable of filtering the molten polymer. An annular ring member encircles the tip member and is slidably positioned within the bore between the upstream and downstream flanges. The ring member is capable of sliding between the flanges for directing the molten polymer through the filter or preventing back flow of the molten polymer past the upstream flange. An end stop is positioned relative to the bore and is capable of engaging and preventing movement of the ring member past the end stop while allowing the downstream flange of the tip member to be translated forwardly therepast to simultaneously space the upstream and downstream flanges apart from the ring member. This directs the molten polymer past upstream surfaces of the filter for purging contaminants filtered from the molten polymer.

Inventors: Wildman; Paul D. (Saugus, MA)

Assignee: Dynisco Extrusion, Inc.

International Classification: B01D 29/31 (20060101); B01D 29/33 (20060101); B01D 33/073 (20060101); B01D 35/147 (20060101); B01D 35/14 (20060101); B01D 33/06 (20060101); B29C 45/20 (20060101); B29C 47/68 (20060101); B29C 47/58 (20060101); B29C 45/24 (20060101); B29C 045/00 ()

Expiration Date: 01/02/2018