The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 26, 1980
Filed:
Oct. 04, 1977
Henry G Horsewell, Totton, GB;
John D Green, Romsey, GB;
John A Luke, Romsey, GB;
Stanley M Candlish, Lachine, CA;
British-American Tobacco Company Limited, London, GB;
Abstract
A tobacco-smoke filter comprises a plug of filter material of which a transverse cross section is impervious to the passage of smoke except for a minor proportion of the area of that cross section which forms a smoke-accelerating orifice, the plug being enclosed by an envelope permitting ingress of air into a region of the plug downstream of the orifice. The cross section may be impervious because of the presence of a barrier diaphragm of impervious material. Thus an annular groove may be provided in the plug at the cross section and may be filled with, or have its walls coated with, an impervious material. Alternatively the cross section may be impervious by reason of the closure of interstices in the filter material by the local application of heat thereto.