Melt bleeder extruder
CA 2273433 C · Owner: Barr, Robert A. · Inventors: Barr, Robert A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An extruder screw mechanism has a barrel that is heated by heating coils, an internal screw, and a cylindrical melt sleeve having a plurality of circumferentially spaced, axially extending radial slots therethrough located, between the external barrel and the internal screw. Another embodiment of the extruder has a barrel and an internal screw with the internal screw having , either a single central axial bore or a plurality of internal axial bores. The internal screw is, provided with a plurality of external threads with the threads each having a , curved starting portion with a helix angle that has a finite value and gradually increases, along an initial portion of the screw until the …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed June 1, 1999 and granted September 9, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 1, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 1, 2021.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.