Compression screw with combination single and double flights
CA 2534113 C · Owner: Keller, Joseph L. · Inventors: Keller, Joseph L.; Riotto, Anthony M.; Kraft, Michael J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A screw for a compression dewatering device comprising an elongated shaft having axially spaced apart first and second ends a conveying section at the first end of the shaft having a single helical screw flight rigidly projecting from the shaft a flightless transition section axially adjacent the conveying section and a dewatering section axially adjacent the transition section having a double helical screw flight rigidly projecting from the shaft. Another embodiment is a compression screw having a perforated tubular dewatering wall intermediate the ends followed by an imperforate spool wall at the discharge end. The screw includes a central shaft a conveying section extending axially from …
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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 January 27, 2006 and granted July 9, 2013. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 27, 2026.
- Certificates of supplementary protection extend only drug patents, and it isn't classified as one.
- 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.