Abstract: A plastic metering machine or assembly mounted on a plastic extruder, feeds plastic aggregate material of two different bulk densities simultaneously into the barrel of an extruder. The assembly has a housing which is divided into two compartments or hoppers by a downwardly converging wall which feeds into the mouth of a funnel on the upper end of a feed tube which passes through the lower compartment and terminates at its lower end adjacent to or in the entrance to the extruder. The feed tube has an external auger which, when the feed tube is rotated, meters the material in the lower compartment into the extruder. The feed tube also has outwardly extending arms which form anti-bridging elements for agitating the material in the lower compartment. A blower feeds plastic scrap material to a grinder which also receives sheet plastic scrap material and loose plastic scrap. The ground scrap from the grinder is fed into the lower compartment as the low bulk density material.

Abstract: A system for drying particulate materials such as amorphous polyethylene teraphthalate or other materials that tend to fuse or agglomerate while being heated includes the steps of directing into the lower portion of a dispensing hopper filled with particles of the material a stream of hot dry air at a temperature above the temperature range in which the particles are unstable and tend to cling to one another and allowing the stream of air to pass upwardly through the particles in the hopper and to transfer its heat to the particles and form a temperature gradient in the body of particles in the hopper which is higher than the critical temperature range of the material at the lower portion of the hopper and which causes the particles to pass through the critical temperature range as the particles are dispensed downwardly from the hopper. The particles are agitated in the critical temperature range to prevent the particles from clinging to one another.