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Expired Canadian patentCanada

Conversion circuit for an electromagnetic flow transmitter

CA 2066571 C · Owner: Rosemount Inc. · Inventors: Wehrs, David L.

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A magnetic flowmeter generates an alternating potential (V19) representing flow. A controlled current (I12) excites the flowmeter with first and second amplitudes of current. A correction output (I26) represents the first and second amplitudes. A circuit (36) connected to the correction output (I26) and the alternating potential (V19) oscillates at a frequency representing the alternating potential corrected for variation of the first and second amplitudes. Frequencies of the oscillations at first and second amplitudes are measured (38). An output is calculated (39) as a function of a subtraction of the first and second measured frequencies such that the effect of offset is reduced.

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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 September 13, 1990 and granted November 28, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 13, 2010.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 13, 2012.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 13, 1990
GrantedNovember 28, 2000
Term endedSeptember 13, 2010
Patent numberCA 2066571 C
Classification (IPC)G01F1/60

Timeline

Timeline From CIPO dates

1991199319951997199920012003200520072009Application filedSep 13, 1990Patent grantedNov 28, 2000Term endedSep 13, 2010

Sources & verification

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