Patent ID: 7147460

Claim:
An apparatus which may be used for producing plastic articles by forming a polymer, wherein the apparatus comprises: a) a polymer feed hopper; b) a heating means to heat and move a melting polymer; c) a forming means to form melted polymer; and d) at least one gas injection means to inject a gas into the hopper, wherein the gas injection means comprises: 1) at least one gas injection surface near a wall of the hopper; 2) a gas feed pipe to supply gas to the hopper through the injection surface, wherein the pipe comprises: i) a first end connected to a gas supply; ii) a second end directed towards the injection surface, wherein the second end is closed; and iii) at least one radial opening o which allows the gas to be ejected from the pipe at substantially a right angle to the direction of gas flow within the pipe; and 3) a homogenization chamber positioned around the injection surface and the gas feed pipe such that the gas exiting the pipe enters the homogenization chamber prior to entering the hopper through the injection surface.