Cigarette filter for both inhaled and exhaled smoke incorporates a flap valve to switch between inlet and outlet ducts with separate filter elements

摘要

A cigarette filter which absorbs harmful products from both inhaled and exhaled smoke had a conventional filter element (2) adjacent to the tobacco (8) for filtering the inhaled smoke. A valve element is fitted between the mouthpiece (5) and the inlet filter and comprises a flap valve (11) which swings between the inlet port (9) and a lateral outlet port (10) leading to a second filter element (4) and through which the exhaled smoke is ducted. The flap valve is moved between the end settings by the cyclic inhaling and exhaling to reduce the harmful smoke products for 'passive smokers'. The output filter element can be treated with aromatic oils.