Polymer filteration apparatus and method of use

A method of forming a filtration apparatus for an injection molding machine, the injection molding machine including a screw housed within a bore for generating molten polymer, the method comprising the steps of:

• axially extending a tip member from the screw, the tip member having radially extending upstream and downstream flanges positioned axially apart from each other with an intermediate shaft portion therebetween, the intermediate shaft portion having a series of first recesses, each extending longitudinally along the intermediate shaft portion between the flanges, and a series of second recesses, each starting from a position spaced from the upstream flange and extending longitudinally along the intermediate shaft portion and through the downstream flange, each first and second recess being laterally separated from each other by a filter element of a filter encircling the tip member for filtering the molten polymer;
• slidably positioning an annular ring member within the bore and encircling the tip member between the upstream and downstream flanges, the ring member capable of slidably engaging the downstream flange for directing the molten polymer through the filter from the first recesses into the second recesses, as well as slidably engaging the upstream flange for preventing back flow of the molten polymer past the upstream flange;
• and
• positioning an end stop within the bore 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 for allowing the molten polymer to bypass the filter for purging contaminants filtered from the molten polymer.

A filtration apparatus for an injection molding machine, the injection molding machine including a screw housed within a bore for generating molten polymer, the filtration apparatus comprising:

• a tip member extending axially from the screw, the tip member having radially extending upstream and downstream flanges positioned axially apart from each other;
• a filter encircling the tip member for filtering the molten polymer;
• an annular ring member encircling the tip member and slidably positioned within the bore between the upstream and downstream flanges, the ring member capable of slidably engaging the downstream flange for directing the molten polymer through the filter as well as slidably engaging the upstream flange for preventing back flow of the molten polymer past the upstream flange;
• and
• an end stop positioned within the bore 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 for allowing the molten polymer to bypass the filter for purging contaminants filtered from the molten polymer.

A filtration apparatus for an injection molding machine, the injection molding machine including a screw housed within a bore for generating molten polymer, the filtration apparatus comprising:

• a tip member extending axially from the screw, the tip member having radially extending upstream and downstream flanges positioned axially apart from each other with an intermediate shaft portion therebetween, the intermediate shaft portion having a series of first recesses, each extending longitudinally along the intermediate shaft portion between the flanges, and a series of second recesses, each starting from a position spaced from the upstream flange and extending longitudinally along the intermediate shaft portion and through the downstream flange, each first and second recess being laterally separated from each other by a filter element of a filter encircling the intermediate shaft portion for filtering the molten polymer;
• an annular ring member encircling the tip member and slidably positioned within the bore between the upstream and downstream flanges, the ring member capable of slidably engaging the downstream flange for directing the molten polymer through the filter from the first recesses into the second recesses, as well as slidably engaging the upstream flange for preventing back flow of the molten polymer past the upstream flange;
• and
• an end stop positioned within the bore 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 for allowing the molten polymer to bypass the filter for purging contaminants filtered from the molten polymer.