System for removal of impurities from shredded tobacco recovered from defective cigarettes

Abstract

A system is used for removal of impurities from shredded tobacco recovered from defective cigarettes, especially activated carbon particles, as used in a machine for recovering tobacco and having separating sieves and suction devices, where in a transport zone for a mixture of shredded tobacco, paper and impurities, positioned directly downstream the device for final tearing of the cigarette paper, with the zone defining a turbulent flow zone for the mixture of shredded tobacco, paper and impurities, a separating device is installed which defines a first purification zone. The device has a grid, a vacuum system for maintaining turbulent flow of the mixture of shredded tobacco, paper and lightweight impurities, positioned above the grid having a mesh size larger than the size of heavy impurities, and a vacuum system for receiving heavy impurities. Then a second purification zone includes a vibrating sieve with a mesh size larger than the size of heavy and lightweight impurities. A vacuum dust removing device, defining a third purification zone, has a transport pipe with flow disturbing elements, a rotational sieve having a grid of a mesh size suitable for suction of volatile impurities, a flow guide means adjacent the sieve and defining at the same time a flow disturbing element, and a rotary chamber valve positioned under the sieve.