Cap for underdrains in gravity filters
CA 2064390 C · Owner: Brown, Marvin A. · Inventors: Brown, Marvin A.; Beverly, Richard P.; Wolfe, Gerald D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cap for filter underdrain blocks is provided wherein the cap has a porous body with a top surface a, bottom surface and downwardly extending flanges. The cap is installed on a filter block having a plurality of orifices in a top wall of the filter block for channelling fluids to and from an overlying filter media. The bottom surface of the cap along with the flanges define a distribution chamber above the orifices and the, cap has a porosity such that a fine grain filter media may be placed directly on the top surface of the cap without media penetrating therethrough and clogging the underdrain blocks. The distribution chamber enhances distribution of backwash fluids throughout the filter …
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 March 30, 1992 and granted April 29, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 30, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 30, 2014.
- 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.