Slotted scallops or similar articles and method of making same
CA 2104584 C · Owner: Wheelabrator Water Technologies Inc. · Inventors: Evans, Thomas W.; Uban, Stephen A.; Norell, Robert G.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An elongated screen assembly, which in various forms is useful as a scallop , in a reactor, or as an underdrain for a gravity filter system, has a cross-section in a direction normal to its axis which is at least twice as wide as it is high. A method is also disclosed for manufacturing the screen assembly by pressing the opposed sides of a wrapped wire cylindrical screen assembly between a pair of plates which have radii of curvature which are different from each other and greater than the radius of curvature of the cylindrical screen assembly.
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 February 28, 1991 and granted August 8, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 28, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 28, 2013.
- 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.