Patent ID: 7393479

Claim:
An injection molding three way valve assembly configured to be disposed to control a flow of a molten material from an injection unit to a runner system, said injection molding three way valve assembly comprising: a valve plunger configured to be disposed between the injection unit and the runner system, said valve plunger having a flow-through channel and a purge channel; and structure configured to control the position of said valve plunger between (i) a molten material flow position where the molten material flows through the flow-through channel, (ii) a molten material blocked position where the molten material is blocked from flowing through the flow-through channel, and (iii) a molten material purge position where the molten material flows through the purge channel, without disconnecting the injection unit from the runner system, said structure configured to control including: a first piston configured to move said valve plunger between the molten material flow position, the molten material blocked position, and the molten material purge position; a controller configured to control movement of said first piston; a second piston configured to reduce the movement of said first piston in the molten material flow position and the molten material blocked position, and said controller is configured to control the movement of said second piston.