Underdrain for granular medium filter
CA 2061241 A1 · Owner: Zimpro Passavant Environmental Systems · Inventors: Ross, David S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
D.N. 2464, IMPROVED UNDERDRAIN FOR, GRANULAR MEDIUM FILTER ABSTRACT, An improved apparatus and method for operating a granular medium filter is disclosed. The apparatus comprises an improved underdrain structure made up of a plurality of rectangular compartments which allows the filter bed to be "air pulsed" as well as backwashed for thorough cleaning of the bed. Nozzles are positioned within the rectangular compartments and directed vertically into the filter bed. Fluid from the nozzles helps to break up the bed during backwashing as well as counteract size classification of the medium during this process. The method of operating a filter with the improved underdrain structure is also …
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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 February 14, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 14, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 14, 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.