Well rig lift system and a hydraulic energy-storing well rig lift system
CA 2085044 C · Owner: Drilling Technology Research Institute Of Shengli Oilfield · Inventors: Zhian, Liu; Dongchang, Sun; Wei, Pan
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A well rig lifting system and a hydraulic energy-storing well rig lifting system, wherein a high pressure energy-storing cylinder and a composite cylinder or cylinder group are used to carry out the lifting and lowering operations. During the lifting operation, a power machine under a substantially constant load continuously pumps oil to the energy-storing cylinder, and communication relationships of the energy-storing cylinder with various chambers of the composite cylinder or cylinder group is selected to provide an appropriate lifting force to lift the pipe string. Therefore the installed capacity, of the power machine can be reduced to 1/3-1/4 of that in a conventional lifting system. …
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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 December 10, 1992 and granted March 28, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 10, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 10, 2014.
- 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.