APPARATUS AND METHOD FOR THE SEPARATION OF HETEROGENEOUS WASTE

Abstract: The invention relates to an apparatus for the separation of heterogeneous waste into a relatively light fraction and a relatively heavy fraction, comprising a vertical or subtantially vertical air duct which is provided with a side opening for supplying the waste, means for drawing air or some other gas upwardly through the air duct and a vibrating conveyor for introducing the waste into the air duct. The vibrating conveyor comprises a conveyor belt, thus preventing the relatively light material from sticking to the vibrating conveyor. Moreover, it is possible to control the supply of the heterogeneous waste more accurately.

Description: Apparatus and method for the separation of heterogeneous waste The invention relates to an apparatus for the separation of heterogeneous waste into a relatively light fraction and a relatively heavy fraction, comprising a vertical or substantially vertical air duct which is provided with a side opening for supplying the waste, means for drawing air or some other gas upwardly through the air duct and a vibrating conveyor for introducing the waste into the air duct. It is known, for example from US patent no. 5,308,368, to separate a mixture of materials, such as stone, various kinds of metals, glass, compost and paper by depositing the material onto a vibrating conveyor and supplying it to an extraction plant. On said vibrating conveyor, the material is separated into a lower layer of relatively heavy pieces and an upper layer of relatively light pieces. The light pieces are removed from the vibrating conveyor by means of a suction nozzle, whilst the heavy pieces fall from the vibrating conveyor at one end thereof under the influence of the force of gravity. Furthermore an apparatus is known wherein heterogeneous material is deposited on a vibrating conveyor, such as a downwardly sloping vibrating chute, which material is introduced into an air duct, through a side opening therein, by means of said vibrating conveyor. Fans are used to generate an upward air flow in said air duct, which air flow carries up the light fraction of the material being supplied, which has already been separated, whilst the heavier fraction falls down against the air flow. Such an apparatus may be fitted with an adjustable venturi . This makes it possible to vary the acceleration of the air that is used for the separation process in dependence on a specific waste material. The aforesaid apparatuses are for example used for ω t H M o LΠ o σι o π The invention furthermore relates to a method for the separation of heterogeneous waste into a relatively light fraction and a relatively heavy fraction, wherein the waste is spread and introduced into a vertical or substantially vertical air flow by means of a vibrating conveyor comprising a conveyor belt, as well as to a method for obtaining a solid fuel from heterogeneous waste . The invention will now be explained in more detail with reference to the figures, which schematically show an embodiment of the apparatus according to the present invention. Figure 1 is a schematic, sectional view of the main components of an apparatus according to the invention. Figures 2 and 3 are a top plan view and a side elevation, respectively, of a vibrating conveyor for use in the apparatus of Figure 1. Figure 4 is a cross-sectional view of a pulley as used in the vibrating conveyor according to Figures 2 and 3. Figure 1 is a sectional view of a vertical screening unit 1, which comprises an air duct 2 having an open end 3, which air duct 2 communicates with a cyclone 4, which in turn communicates with a filtering unit 5. Filtering unit 5 comprises, for example, a cascade of two, four or six fans 6, each having a capacity of for example -4000 m 3 /hour, by means of which it is possible to generate a reduced pressure in filtering unit 5 and thus an air flow through cyclone 4 and air duct 2. Heterogeneous waste is introduced into the air duct 2, via a side opening 8, by means of a vibrating conveyor 7. Said waste may be household waste and/or industrial waste, for example, and it may have been presorted and/or preshredded. Such waste may for example comprise one or more of the following components: carpet remnants, plastics such as PVC, HDPE, PE, PP, etc., textile, paper and/or wood remnants, all of which are generally considered to form part of the light fraction, as well as ferrous and non-ferrous metals, sand, stone remnants, glass and ceramics, all of which will generally be considered to form part of the heavy fraction. The dimension of these pieces of waste will generally range between 1 - 300 mm, whilst the density of the pieces will usually range between 5 - 250 kg/m 3 . The light fraction may for example comprise 80 - 99 per cent by weight of the heterogeneous waste, whilst the heavy fraction comprises 1 - 20 per cent by weight thereof. Air duct 2 is provided with an adjustable venturi 9 at the location of side opening 8, which venturi in the main consists of a constriction 9', which is made up of two plate members 10, 10' which are pivotally connected to each other and to a wall of air duct 2. Said plate members 10, 10' can be moved inwards or outwards by means of a long adjustment bolt 11, by means of which constriction 9' can be reduced or enlarged. The other side of constriction 9' is made up of the right-hand (in the drawing) end 12 of vibrating conveyor 7, which end 12 extends through side opening 8. A wedge 13 is mounted below said end 12, which wedge directs the air flow to the farthest point of end 12 in order to thus prevent, or at least reduce, the occurrence of turbulence in the air duct 2. Since venturi 9 is adjustable, it is possible to regulate the air speed accurately, in dependence on the composition of the heterogeneous waste, at the location where the actual separation takes place. Positioned below the above-described venturi 9 is a second venturi 14, which ensures that components of the light fraction that have been dragged down by the heavy fraction can be carried up yet in the accelerated air flow that has been generated by said second venturi 14. 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It has become apparent that an effective transport both of the light pieces and of the heavy pieces in heterogeneous waste can be obtained by using a vibrating conveyor comprising a conveyor belt, also if the waste consists of relatively light pieces for the larger part. In addition, a high degree of separation or segregation is obtained. It is possible with the apparatus according to the invention to purify the aforesaid light fraction thoroughly, to such a degree that said fraction can be processed into pellets by means of an extruder, without said extruder being damaged or getting clogged by, for example, metal or glass remnants. Depending on their composition, such pellets may suitably be used as an alternative fuel for generating energy or producing electricity. The invention is not restricted to the embodiments as described above, of course, which can be varied in several ways without departing from the scope of the invention as defined in the claims.

Claims: CLAIMS 1. Apparatus for the separation of heterogeneous waste into a relatively light fraction and a relatively heavy fraction, comprising a vertical or substantially vertical air duct which is provided with a side opening for supplying the waste, means for drawing air or some other gas upwardly through the air duct and a vibrating conveyor for introducing the waste into the air duct, characterized in that said vibrating conveyor comprises a conveyor belt . 2. Apparatus according to claim 1, wherein the speed of the conveyor belt is controllable. 3. Apparatus according to claims 1 or 2 , wherein elongated, rotatable rollers are disposed below the upper part of the belt, which rollers are provided with projections, which push the belt up locally upon being rotated. 4. Apparatus according to claim 3, wherein said belt is passed over at least one driving pulley and one bend pulley, and wherein said elongated rollers are connected to said driving pulley in such a manner that when the driving pulley is driven, the circumferential speed of said elongated rollers is higher than the carrying velocity of the belt. 5. Apparatus according to any one of the preceding claims, wherein the air duct is provided with a venturi at the location of the side opening. 6. Apparatus according to claim 5, wherein the constriction of the venturi is adjustable. 7. Apparatus according to claim 5 or 6, wherein one end of said vibrating conveyor extends through the side opening for the supply of waste, thereby partially defining the venturi. 8. Apparatus according to claim 7, wherein a wedge is disposed on the inside of the air duct, below the end of the vibrating conveyor that extends through the side opening for the supply of waste, the wide end of which wedge is positioned below the aforesaid end of the vibrating conveyor. 9. Apparatus according to any one of the claims 5 - 8, wherein a second venturi is disposed below the aforesaid venturi . 10. Apparatus according to any one of the claims 5 - 9, wherein a false air valve is disposed above the venturi in the air duct, by means of which valve the flow, and thus the velocity of the air or the gas in the venturi, can be controlled or set. 11. Method for the separation of heterogeneous waste into a relatively light fraction and a relatively heavy fraction, wherein a vertical or substantially vertical air flow is generated and the waste is spread and introduced into said air flow, characterized in that said spreading and introducing into the air flow of the waste is carried out by means of a vibrating conveyor comprising a conveyor belt. 12. Method for obtaining a solid fuel from heterogeneous waste, characterized in that a vertical or substantially vertical air flow is generated and heterogeneous waste comprising a combustible, relatively light fraction and a relatively heavy fraction is separated into said fractions by being spread and being introduced into said air flow. 13. Method according to claim 11, wherein said spreading and introducing into the air flow of the waste is carried out by means of a vibrating conveyor comprising a conveyor belt . 14. Method according to claim 11 or 13, wherein elongated, rotatable rollers are disposed below the upper part of the belt, which rollers are provided with projections, which push the belt up locally and temporarily upon being rotated. 15. Method according to any one of the claims 11 - 14, wherein said light fraction is subsequently processed into pellets.

Inventors: DUIJN CORNELIS GERARDUS SEBAST, OSTERMEIJER RENE HENDRIK JAN, VAN DER KOLK JOHANNES HUBERTUS, DUIJN, CORNELIS, GERARDUS, SEBASTIANUS, OSTERMEIJER, RENE, HENDRIK, JAN, VAN DER KOLK, JOHANNES, HUBERTUS,
Applicants: DUIJN CORNELIS GERARDUS SEBAST, DUOS B V, KOLK JOHANNES HUBERTUS V D, OSTERMEIJER RENE HENDRIK JAN, DUIJN, CORNELIS, GERARDUS, SEBASTIANUS, DUOS B.V., OSTERMEIJER, RENE, HENDRIK, JAN, VAN DER KOLK, JOHANNES, HUBERTUS,
Application year: 2001
Main classification: B07B11
IPC codes: B03B9, B07B4, B07B11