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Expired Canadian patentCanada

Reverse osmosis system

CA 1251145 A · Owner: U.S. Filter/Arrowhead, Inc. · Inventors: Pittner, Gregory A.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A chemically enhanced reverse osmosis water purification system and process is provided in which the inlet of a second reverse osmosis unit is coupled in series to the product water outlet of a first reverse osmosis unit. Water to be purified is conditioned by an ion exchange resin type water softener and pumped to the inlet of the first reverse osmosis unit. The product from the first reverse osmosis unit is treated with a chemical treatment agent, such as a sodium hydroxide solution upstream of the inlet, to the second reverse osmosis unit. The brine from the brine outlet of the second reverse osmosis unit is recirculated to the water flow line upstream of the first reverse osmosis unit.

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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

  • Granted March 14, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 14, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 24, 1985
GrantedMarch 14, 1989
Term endedMarch 14, 2006
Patent numberCA 1251145 A
Classification (IPC)C02F1/44 +1 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedMay 24, 1985Patent grantedMarch 14, 1989Term endedMarch 14, 2006

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.