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Expired Canadian patentCanada

Control of froth cell performance through the use of differential bubbler tubes

CA 1258542 A · Owner: Conoco Inc. · Inventors: Scandrol, Roy O.; Sandbrook, Thomas D.

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Abstract From the Canadian patent

A method of controlling the separation of coal from a mixture of coal and refuse in a froth flotation device by measuring the differential back pressure between two gas bubbler tubes immersed to different depths into the body of pulp in the device to produce a first control signal representative of the pulp density and, adjusting the rate of addition of a froth enhancement additive to the froth flotation device responsive to changes in said first signal; a second signal, produced by measuring back pressure of a single bubbler tube and representative of the pulp level in said device, can be corrected for changes in density by combining it with said first signal and then utilized to control …

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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 August 15, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 15, 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.
FiledAugust 21, 1985
GrantedAugust 15, 1989
Term endedAugust 15, 2006
Patent numberCA 1258542 A
Classification (IPC)B03D1/02 +2 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedAug 21, 1985Patent grantedAug 15, 1989Term endedAug 15, 2006

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