Filter underdrain system for backwash flow and method for measuring same
CA 2543681 C · Owner: Hambley, Philip · Inventors: Hambley, Philip; Hambley, David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A filter underdrain system and a method for measuring the water flow through the underdrain filter system. The apparatus includes panel members assembled to form a perforate grid on the filter base structure of an underdrain block. The panels are generally rectangular and have an upper and lower surface. Multiple apertures are provided in the panel member. The number and/or size of the apertures are dimensioned to prevent the egress of filter media and to obtain substantially uniform backwash flow in the underdrain thereby reducing or eliminating water maldistribution.
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 April 30, 1999 and granted November 27, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 30, 2019.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 30, 2021.
- 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.