US Patent 7824175 Injection molding anti-drool nozzle

A shutoff nozzle body and valve assembly operative to reduce molten plastic resin drool when the nozzle body is separated from the mold or runner system. The apparatus includes a porting system that shuts off the flow of resin through the sprue plunger of the valve nozzle body before the valve body seals on the valve seat so as to permit any resin that is within the sprue passages to drain out through the sprue plunger into the mold cavity or runner system before the sprue tip completely withdraws from the mold or runner system thereby eliminating drool.