An injection molding apparatus comprising: a manifold having a manifold melt channel with an outlet for guiding and delivering a molten material, and a guide bore; a hot runner nozzle located between the manifold and a mold gate, wherein the nozzle has a central melt channel communicating with the manifold melt channel to receive the molten material; a pin movable within the nozzle, the pin slidable to open and close the mold gate and controlling the flow of the melt of molten material to the mold gate; a valve located in the guide bore, said valve having a movable valve member for increasing and decreasing flow of melt flowing in the melt channel of the nozzle towards the mold gate, the valve member receiving a pressure force from the melt; and an actuator providing a control force to the valve member, wherein the valve member moves in response to a difference between the pressure force and the control force; characterized in that the valve member is a hollow control rod; wherein the valve further comprises a hollow support extension positioned in the guide bore, and the hollow control rod is slidably disposed within the support extension; wherein the support extension comprises a melt opening aligned with the outlet of the manifold melt channel allowing the melt from the manifold melt channel to reach the central melt channel; wherein the hollow control rod comprises a full section, a narrowed section, and an enlarged valve portion, wherein the full section has an outer diameter to slidably mate with the support extension, the narrowed section is located between the full section and the enlarged valve portion, and the narrowed section has an outer diameter narrower than the outer diameters of the full section and the enlarged valve portion; and wherein the inner diameters of the full section, the narrowed section, and the enlarged valve portion are substantially the same and accommodate the pin therein. a manifold having a manifold melt channel with an outlet for guiding and delivering a molten material, and a guide bore; a hot runner nozzle located between the manifold and a mold gate, wherein the nozzle has a central melt channel communicating with the manifold melt channel to receive the molten material; a pin movable within the nozzle, the pin slidable to open and close the mold gate and controlling the flow of the melt of molten material to the mold gate; a valve located in the guide bore, said valve having a movable valve member for increasing and decreasing flow of melt flowing in the melt channel of the nozzle towards the mold gate, the valve member receiving a pressure force from the melt; and an actuator providing a control force to the valve member, wherein the valve member moves in response to a difference between the pressure force and the control force; characterized in that the valve member is a hollow control rod; wherein the valve further comprises a hollow support extension positioned in the guide bore, and the hollow control rod is slidably disposed within the support extension; wherein the support extension comprises a melt opening aligned with the outlet of the manifold melt channel allowing the melt from the manifold melt channel to reach the central melt channel; wherein the hollow control rod comprises a full section, a narrowed section, and an enlarged valve portion, wherein the full section has an outer diameter to slidably mate with the support extension, the narrowed section is located between the full section and the enlarged valve portion, and the narrowed section has an outer diameter narrower than the outer diameters of the full section and the enlarged valve portion; and wherein the inner diameters of the full section, the narrowed section, and the enlarged valve portion are substantially the same and accommodate the pin therein.