Molding process for forming a sealing gasket on filter media

In a method of molding a gasket on a filter media formed about an axis and having a hollow core, wherein the filter media has an axially extending outer surface, and an axially extending inner surface connected by a radially extending surface, and wherein the gasket is formed by expanding a foam material into a cavity surrounding the outer surface of the filter media, the improvement comprising:

• positioning the filter media proximate a first mold, which first mold has a circular plate portion disposed in spaced relation to the radially extending surface of the filter media and extends perpendicular to the axis of the filter media, the first mold further having a plug which axially extends partially into the hollow core of the filter media in spaced relation to the inner surface of the filter media to define an inner space;
• surrounding the filter element with a second mold having a portion for engagement with the outer surface of the filter media with the exception of an exposed portion of the outer surface of the filter media disposed proximate the radially extending surface;
• the second mold engaging the first mold along a mold line disposed in radial spaced relation to the filter media;
• defining a radially extending cavity with first and second molds, the radially extending cavity extending outboard of the exposed portion of the outer surface of the filter media, the radially extending cavity being in communication with a shallow space between the plate of the first mold and the radially extending surface of the filter element;
• expanding the foam material in the radially extending cavity to advance against the exposed portion of the outer surface of the filter element and through the shallow space between the filter media and the first mold;
• and
• accumulating a portion of the expandable material in a groove formed in the second mold proximate the mold line to prevent the formation of flash on the gasket at the mold line.

A method of forming a sealing gasket about an open end of an air filter media having a hollow core comprising:

• molding expandable foam material about the open end of the air filter media in a laterally extending cavity defined by first and second molds positioned around at least the open end of the air filter media wherein the molds join one another along a mold line;
• expanding a portion of the material away from the mold line into a space located proximate, but axially displaced from, the mold line to form a peripheral bead and to prevent formation of flashing at the mold line;
• and
• venting the cavity at a location displaced radially inward from the space.