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Expired Canadian patentCanada

Differential pressure sensor

CA 1296917 C · Owner: Bruesehoff, Steven M. · Inventors: Knecht, Thomas A.; Frick, Roger L.; Bruesehoff, Steven M.

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 cell for sensing differential pressures has a single brittle material diaphragm mounted on support plates positioned on opposite sides of the diaphragm. The diaphragm surfaces when at zero differential pressure facing the support are concave and shaped to conform very closely to the shape the diaphragm has when it is deflected so that when the diaphragm is under a selected pressure and it is forced against one of the supports in either direction, the diaphragm is substantially planar or flat and supported fully on its support plate. The diaphragm may be shaped by placing it under a pressure so that it bows or deflects and then grinding the surface opposite from the applied pressure flat. …

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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 10, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 10, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 19, 1987
GrantedMarch 10, 1992
Term endedMarch 10, 2009
Patent numberCA 1296917 C
Classification (IPC)G01L7/08 +2 more

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedJune 19, 1987Patent grantedMarch 10, 1992Term endedMarch 10, 2009

Sources & verification

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