Ultra-high filtration filter
AssigneeAmerican Filtrona Corporation
InventorRichard M. Berger
Life of this patent
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Abstract
An ultra-high efficiency cigarette filter is formed from a web of entangled ultra-fine melt blown plastic fibers of extremely low bulk density, the fibers on average having a diameter in the range of 0.1 to 4 microns. The web is formed into a substantially cylindrical rod having a bulk density in the range of 0.029 to 0.046 gram per cc and is encapsulated in and supported by an external plastic tube which adheres to the outer surface of the rod over the entire area of contact therebetween. Cigarette filters in accordance with the invention may have filtration efficiencies in excess of 80%. The disclosure also includes processes and apparatus for manufacturing the high efficiency filters.
Claims18
An elongate fibrous filter body comprising a gas pervious inner core of entangled melt-blown ultra-fine plastic fibers and a surrounding plastic tube for supporting the core, the tube being substantially continously adhered around the core over substantially the entire area of contact therebetween, the fibers, on average having a diameter in the range 0.1 to 4 microns and the core having a bulk density in the range 0.029 to 0.046 gram per cc.
A tabacco smoke filtering means comprising a smoke pervious rod of entangled melt blown plastic fibers having an average diameter in the range 0.1 to 4 microns and a bulk density in the range 0.029 to 0.046 gram per cc, and a plastic tube for supporting the rod, the tube being adhered to the outer surface of the rod to substantially preclude smoke bypass between the rod and the tube.
Dependencies are inferred from the claim text.