Air duct block for air/water underdrain systems in gravity filters
CA 2085680 A1 · Owner: F.B. Leopold Company, Inc. · Inventors: Brown, Marvin A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An air duct block for air/water underdrain systems in gravity filters comprising a row of interconnected air duct blocks positioned below the filtering media and extending transversely to the underdrain laterals. Each air duct block is in communication with at least one adjacent individual underdrain filter block to supply backwash gas thereto during backwashing operations, thereby supplying backwash gas to its associated lateral. Each air duct block is in further communication with at least one adjacent air duct block such that backwash gas flows between the interconnected air duct blocks and along the row of air duct blocks. This system supplies backwash gas to the entire underdrain …
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 December 17, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 17, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 17, 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.