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A valve gated injection molding system for making hollow plastic products. A fixed pin extends through an elongated hollow valve member which is reciprocated between a retracted open position and a forward closed position in which the forward end of the valve member is seated in the gate. The fixed

A valve gated injection molding system for making hollow plastic products. A fixed pin extends through an elongated hollow valve member which is reciprocated between a retracted open position and a forward closed position in which the forward end of the valve member is seated in the gate. The fixed pin has a hollow portion for the flow of pressurized gas to a porous portion at the forward end which is centrally located in the gate. In the open position, gas from the fixed pin flows into the hollow center of a stream of melt which flows into the cavity around the forward end of the fixed pin to form a melt bubble in the cavity.

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In a valve gated hot runner injection molding apparatus having a heated nozzle seated in a well in a cavity plate, the nozzle having a central bore extending therethrough to receive an elongated valve member with a forward end and a rear end and to provide a melt passage which extends in the central

In a valve gated hot runner injection molding apparatus having a heated nozzle seated in a well in a cavity plate, the nozzle having a central bore extending therethrough to receive an elongated valve member with a forward end and a rear end and to provide a melt passage which extends in the central bore around at least a forward portion of the valve member to convey melt to a gate extending through the cavity plate to a cavity, and valve member actuating means to reciprocate the valve member longitudinally between a retracted open position and a forward closed position in which the forward end of the valve member is seated in the gate, the improvement wherein; the elongated valve member is hollow and receives centrally therein an elongated pin having a forward end and a rear end, the pin being securely mounted in a fixed position wherein the forward end of the pin is centrally received in the gate with a space therearound which provides a stream of melt with a hollow center flowing through the space around the forward end of the pin into the cavity when the valve member is retracted to the open position, the pin having a hollow central portion extending from an inlet near the rear end of the pin to an outlet at the forward end of the pin, whereby pressurized gas received at the inlet to the hollow pin flows through the outlet into the hollow center of the stream of melt flowing into the cavity.