Valve pin bushing with vent channels for an injection molding apparatus

An injection molding apparatus comprising:

• a manifold for receiving a melt stream from a source;
• a nozzle having a nozzle channel for receiving the melt stream from said manifold;
• a mold cavity in communication with said nozzle channel for receiving melt through a mold gate;
• a valve pin extending through said nozzle channel for selectively opening said mold gate;
• a valve pin bushing provided on an opposite side of said manifold from said nozzle, said valve pin bushing having a bore for slidably receiving said valve pin;
• a chamber provided in said valve pin bushing, said chamber being in communication with said valve pin bore;
• a first channel provided in said valve pin bushing, said first channel extending between an outer surface of said valve pin bushing and said chamber;
• a second channel provided in said valve pin bushing, said second channel extending between said chamber and said outer surface of said valve pin bushing;
• and
• a forced fluid source in communication with said first channel of said valve pin bushing to force fluid through said first channel, said chamber, and said second channel.