Temperature control system for a cryogenic refrigerator
CA 2000359 C · Owner: Pruitt, Gerald R. · Inventors: Pruitt, Gerald R.; Higham, Graham J.; Livingstone, James
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a cryogenic refrigerator utilizing a linear drive motor, a temperature control system controls the displacement of an armature reciprocating at a fixed frequency to adjust the operating temperature of a working fluid at the cold end of a cold finger. Linear drive motors using dynamic absorbers to reduce vibration operate within the narrow frequency range to which the absorber is tuned. Controlling the maximum displacement of the armature used to compress the working fluid results in the ability to adjust the temperature at the cold end of the refrigerator without altering the frequency of operation.
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 October 10, 1989 and granted December 9, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 10, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 10, 2011.
- 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.