METHOD AND APPARATUS FOR SEPARATING TOBACCO FROM CIGARETTE WASTE

An apparatus for separating tobacco from cigarette waste including a revolving screen having a bottom surface by which the screen is mounted in the apparatus at an acute angle relative to the horizontal plane, the screen further having a top surface, the angular position of the screen with respect to a horizontal plane being adjustable and the screen being provided with scraping unit on the top surface of the screen for aiding relocation of the cigarette waste on the top surface of the screen during its rotational movement.

The apparatus according to the invention, shown inFIG. 1, comprises a circular, revolving screen1, mounted rotatably on a rotational axis X, the angular position of the screen surface in the apparatus relative to the horizontal plane being adjustable. The angle a may be adjusted depending on the humidity of the cigarette waste. To adjust the angular position of the screen surface typical means may be used that were not shown in detail in the figures and have been designated as means K. The apparatus is provided with scraping means2enabling relocation of the cigarette waste3on the surface of the screen on rotating of the screen. The screen1is delimited on its periphery by a wall4. The screen and optionally the scraping means are driven in rotation by means of a motor5, in the direction shown in the figures by an arrow.FIG. 1shows the embodiment of he apparatus in which the scraping means2are rotatably mounted on the axis Y coinciding with the axis of the screen.FIG. 2shows the embodiment of the apparatus in which the scraping means2are fixed to the surface of the screen1. In the apparatus shown inFIG. 3the screen is positioned horizontally and the scraping means2are rotatably mounted on the axis Y and move relative to the surface of the screen1. In the embodiment where the scraping means2are rotatably mounted on the axis Y coinciding with the axis of the screen or parallel to the axis of the screen, they may be rotated with the same rotational speed as the screen or with a different rotational speed. Hence, even with the scraping means independently rotating over the screen, it is possible to keep them immovable relative to the surface of the screen.

FIGS. 4 and 5show various examples of the possible arrangements of the scraping means2,2′ in the form of low walls positioned substantially perpendicularly to the surface of the screen and having a spiral shape. Optionally, they may have the form of mutually separated slats arranged along lines that do not go through the center of the screen. The slats may e.g. be straight as shown onFIG. 7andFIG. 8.FIG. 5additionally shows the larger mesh sizes located adjacent to the axis of the screen.

FIG. 6shows an example of the scraping means2rotatably mounted on the axis Y which is parallel to the axis of the screen and not coinciding therewith.

FIG. 9shows a schematic view of the screen with circulation driving means in the form of three eccentric rollers6cooperating with the outer periphery of the screen. In this embodiment the screen is mounted rotatably by typical means enabling its circulation movement. The eccentric rollers6drive the screen in circulation movement in addition to the rotation.FIG. 9shows two momentary positions of the screen during its movement, one being shown with a continuous line and the other with a dashed line. The cigarette waste located on the screen is additionally relocated in parallel to the surface of the screen which improves the effectiveness of the screening.

FIGS. 10 and 11show a schematic side view of the apparatus according to the invention provided with screen cleaning means in the form of a brush7sweeping the screen and one suction nozzle8—FIG. 10, and in the form of one suction nozzle and one over pressure nozzle—FIG. 11.FIG. 12shows an embodiment of the screen having the scraping means in the form of the slats that are perpendicularly fixed to the surface of the screen, arranged along a spiral line.

The cigarette waste is thrown onto the operating surface of the screen1of the apparatus for separating tobacco from wrappers and filters. After the apparatus has been turned on, the screen1is rotated and the scraping means2, aiding to relocate the cigarette waste3move along with the screen. Means2may rotate with the same rotational speed as the screen or with a different rotational speed. The function of the scraping means2is to relocate the cigarette waste3in such a way that it is distributed all the time on the largest possible area of the screen surface1. It means that in the case of the circular revolving screen1positioned slantwise relative to the horizontal plane, at a given moment of the rotations of the screen, both the lower part of the screen surface and its upper part are operatively effective, i. e. both parts are in contact with the cigarette waste3. Before being fed to the screen1, the cigarette waste3undergoes a treatment consisting in cutting open the cigarette paper being cigarette wrapper, while the tobacco is taken out from the cigarettes on the screen. During operation of the apparatus, the mixture of cigarettes, cigarette wrappers and filters is divided into the fractions having different bulk density. The function of the scraping means2is to relocate first of all the fraction of the cigarette waste3located closest to the screen surface, i. e. the tobacco and the cigarettes that have not yet been emptied. The fractions having low bulk density, like big pieces of the wrappers or filters with pieces of wrappers stuck on are not as much relocated as the tobacco and the full cigarettes. The scraping means2may be rotatably mounted on the axis Y independently on the axis X of the screen in such a way that they may be rotated with a speed synchronized with the rotational speed of the screen. It is also obtainable to rotate the scraping means2with a different rotational speed than the rotational speed of the screen which would result in that the scraping means2would be additionally sweeping the screen surface. In such a case, the scraping means2are functional also when the surface of the screen is positioned horizontally.

In another embodiment of the invention, shown onFIG. 2, the scraping means2are fixed to the screen surface. Here, the scraping means2are functional only when the surface of the screen is positioned slantwise. The cigarette waste3located on the screen, tending to fall down by gravity is simultaneously “taken up” by the scraping means2rotating along with the screen and relocating the waste on the screen surface.

The apparatus according to the invention is provided with typical means for adjusting the angular position of the screen and the means for changing its rotational speed. The screen used in the apparatus may have radially variable mesh size.