Fume hood sash sensing apparatus
CA 2049415 C · Owner: Sharp, Gordon P. · Inventors: Sharp, Gordon P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention provides apparatus for sensing the extent to which the sash or sashes covering the access opening of a fume hood are open. The apparatus includes a source of electromagnetic energy at a selected AC frequency below 10 6 MHz, with a preferred frequency range being from 10 KHz to 100 KHz. The source preferably includes a wire coil connected to an oscillator of the selected frequency with the detector for the AC signal also preferably including a wire coil. Suitable elements are also provided for controlling the amount of electromagnetic energy from the source wire coil which reaches the detector wire coil as a function of sash opening. For the various embodiments, the apparatus …
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 August 16, 1991 and granted December 28, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 16, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 16, 2013.
- 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.