Apparatus for plasticizing particulate plastic material

An apparatus for plasticizing particulate plastic material, the apparatus comprising:

• a housing, the housing having a bore therethrough, and the bore having an inlet end and an outlet end;
• means for feeding particulate plastic material into the bore at the inlet end;
• an auger positioned in the bore, the auger having an inlet end to receive material from the means for feeding and a discharge end at an intermediate location in the bore;
• means for rotating the auger to convey the particulate plastic material from the means for feeding along the bore and to frictionally melt the particulate plastic material before the particulate material passes the discharge end;
• means for controlling the speed of rotation of the auger to control the flow rate of melted plastic through the outlet end;
• a smooth-walled, cylindrical rotor positioned in the bore between the auger and the outlet end, the bore and the rotor defining an annulus therebetween, the rotor having a first end positioned proximate to the discharge end of the auger, the rotor having an axial length and the annulus extending from the first end along the length of the rotor;
• means for rotating the rotor to heat the melted particulate plastic material passing from the discharge end of the auger and through the annulus, independent of the flow rate of melted plastic through the annulus;
• and
• means for controlling the speed of rotation of the rotor for obtaining a desired temperature of melted plastic particulate material at the outlet end of the housing.