Hydrostatic referenced safety-circulating valve
CA 1270752 C · Owner: Haliburton Company · Inventors: Winslow, Donald W.; Zunkel, Gary D.; Newman, Daniel A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
85.030Al, Abstract Of The Disclosure, An annulus pressure responsive downhole tool includes a housing with an operating element disposed in the housing. The operating element is movable from a first element position to a second element position relative to the housing. A hydrostatic well annulus pressure referenced annulus pressure responsive first power piston is disposed in the housing and movable from a first to a second position thereof relative to the housing in response to an increase in well annulus pressure. A lower than hydrostatic well annulus pressure referenced annulus pressure responsive second power piston is disposed in the housing and is operatively associated with the …
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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 June 26, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 26, 2007.
- 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.