Filter tipped cigarette with central filling - has tube down middle which burns or melts as tobacco burns

摘要

A filter tipped cigarette intended to reduce the harmful effect of the smoke, has a hollow channel (36) down the middle, extending from one end to the filter tip (31). This space is filled with a heat conducting material or a tube which burns away as the tobacco (32) burns away. The final lip (37) of the tube, in contact with the filter tip is not of heat conducting material. This tip closes the end of the tube. The tube need not be of circular section, and may vary in shape over its length, it can consists of sections joined by waxy or resin. It may be made of graphite, aluminium or tin, and can melt as the tobacco burns. The diameter of the space and the tube have a combined diameter of 0.2 mm, and occupy less than 80% of the tobacco content of the cigarette. The space may be filled with magnesium carbonate. The tube may have one to 15 holes through it, between 0.2 and 0.7 mm in diameter.