Pilot gas bypass system for fuel-fired furnaces
CA 2003793 C · Owner: Harrigill, William T. · Inventors: Harrigill, William T.; Shellenberger, Timothy J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
To inhibit internal heat exchanger corrosion the pro-, ducts of combustion from a standing pilot flame in an induced draft, fuel-fired furnace are prevented from migrating through the heat exchanger during idle periods of the furnace by flowing the products of combustion upwardly through a small vent tube into the outlet section of the draft inducer fan and then into, an external exhaust stack thereby bypassing the heat exchanger. During operation of the draft inducer fan a negative pressure is maintained within the vent tube, to prevent combustion gas outflow therethough which might otherwise snuff out the pilot flame, by a venturi structure positioned within the draft inducer fan outlet …
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 November 24, 1989 and granted August 11, 1992. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 24, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 24, 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.