Eddy current drive and motor control system for oil well pumping
CA 2091707 C · Owner: Wolcott, John H. · Inventors: Sieger, William L.; Wolcott, John H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An eddy current coupling with an electrically controllable field current is used to rotatably connect a drive motor to an oil well pumping mechanism where the eddy current drive speed is controlled to a reference speed using a speed feedback control system and operation can be limited in torque output by a torque feedback control system. in a first alternative embodiment the, eddy current coupling output speed is controlled by a stroke modulation unit using a first selected speed for the upward pumping stroke and a second selected speed for the downward pumping stroke. In a second alternative embodiment a controller is used to select torque or speed control for the upward or downward …
Read the whole patent
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 March 16, 1993 and granted November 30, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 16, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 16, 2015.
- 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.