Apparatus for filtering and extruding synthetic plastic scrap material

Apparatus for processing synthetic plastic scrap material comprising:

• a housing having a cylindrical interior chamber;
• an extruder worm received and supported in said chamber for rotation around an axis, said extruder worm including a centrally located set of return threads on the circumferential surface thereof which divide said chamber into first and second chamber portions, said housing further including an intake opening in said first chamber portion for receiving raw material, an exit opening in said second chamber portion for discharging processed material, and a degassing opening in said second chamber portion for discharging gasses from said chamber;
• drive means for driving said extruder worm;
• a channel connecting said first and second chamber portions, said plastic material passing from said first chamber portion to said second chamber portion through said channel, said channel having an inlet opening in said first chamber portion and an outlet opening in said second chamber portion immediately adjacent said return threads, said degassing opening being located between said outlet opening of said channel and said exit opening of said second chamber portion;
• and
• filter means disposed in said channel for filtering said plastic material as it passes therethrough, said extruder worm having a thread geometry in said second chamber portion which creates a no-pressure zone therein, said no-pressure zone being located between first and second ends of said second chamber portion.