Cigarette filter
CA 1196833 A · Owner: Brown & Williamson Tobacco Corporation · Inventors: Silberstein, Donald A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
UNITED STATES PATENT APPLICATION, of, Donald A Silberstein for, CIGARETTE FILTER, ABSTRACT OF THE DISCLOSURE A filter for a cigarette has a porous filter rod with a channel extending longitudinally through the filter rod. The end of the channel at the tobacco column of the cigarette is closed by a smoke impervious wall having an orifice therein of a smaller cross-sectional area than the cross sectional area of the channel to provide flow communication between the tobacco column and the channel. The filter rod can be circumscribed with an air pervious tipping material.
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
- Granted November 19, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 19, 2002.
- 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.