Conical vent containing capillary bore

摘要

A conical vent (14) for a cartridge (10) is located on an inner surface (20) of the cartridge. The conical vent includes a conical-shaped member (26) having a base (28) and an apex (30). An opening (32) extends through the center of the conical-shaped member (26) to provide an air passage for a cartridge (10). The opening (32) is adapted to create a capillary force on a small amount of liquid (59) that might enter the opening to prevent any remaining liquid from leaking through the opening. The vent also includes a groove or capillary trap (34) that encircles the base of the conical-shaped member. Also, a pair of upright walls (36) and (38) surround the conical-shaped member and cooperate with the capillary trap to divert liquid to the base of the conical-shaped member and away from its apex. A second conical-shaped member (52) integral with an outer surface (22) of the cartridge can be positioned directly opposite the first-mentioned conical-shaped member to help create and maintain the capillary force created in the opening (32). Another capillary trap (56), extending around the second conical-shaped member, traps any liquid that might escape through the opening.