EP0145601B1 - Device for separating sheet material in a refuse processing plant - Google Patents

Abstract

1. A device for separation of sheet material in an apparatus for treatment of refuse, comprising separation means, stop means for the sheet materials, a cyclone (28), a second duct (27) between said stop means and the cyclone, a third duct between the cyclone and the separation means, and a blower (31) for ensuring a flow of air in a circuit formed between the separation means, the stop means, the cyclone, and back to the separation means, through said second and third ducts, characterised in that said separation means comprises a first passage (9), substantially vertical, and means (10, 14) for causing in this first passage an ascending flow of air, in that said device comprises a first duct (16) of venturi shape between said first passage and said stop means to close said air circuit, and in that said first and third ducts open substantially opposite each other on to the upper part of said first passage to cause a transverse flow of air.

Description

The present invention relates to a device for the separation of sheet materials in a waste installation and more particularly to such a device as referred to in the preamble of claim 1.

It is known to make humus from waste, for example from household waste. However, it is known that only the fermentable materials participate in the formation of humus, while the materials which are not or only slightly fermentable, such as plastic bags, rags, papers, cartons, etc., can on the contrary be advantageously used as fuels.

The present invention aims to provide a device for the separation of sheet materials which constitute in waste, and more particularly in urban waste, an essential part of non-ferrous and non-fermentable materials.

A device of the type recalled above is known from document FR-A-2302148. In this device the separation means and the stop means for the sheet materials are arranged in the same chamber at the lower part of which are arranged two screw conveyors, one for the light parts, and the other for heavy parts. Due to the combination of separation means and stop means in the same room, the result obtained is not entirely satisfactory.

It is also known from document US-A-3986949 to discharge waste into a sheath in which an ascending air stream is formed to separate materials of different density. Such a device, not comprising stop means, is ill-suited to the treatment of waste comprising on the one hand sheet materials and on the other hand other materials of low density but of another shape.

In order to overcome these drawbacks, the present invention provides a device as described above and having the characteristics of the characterizing part of claim 1.

The sheet materials which on the one hand are light, and on the other hand have a large surface are thus led by the upward flow to the upper part of the sheath where they are entrained by the transverse flow in the first conduit for their further processing.

Said first sheath can for example be the feed sheath of a first mill. In the case of a hammer mill, it can participate itself, by its rotation, in the formation of the ascending air flow.

Advantageously, said first sheath forms a venturi below the zone into which said first duct opens, which has the effect of causing an acceleration of the upward air flow.

In a particular embodiment of the invention, the surface of said first conduit is inclined upwards towards the interior of the sheath in its zone adjacent to said sheath.

The purpose of this arrangement is to prevent heavy materials, thrown for example by the impact of the hammers of the crusher, from engaging in the first conduit. Such heavy materials indeed hit the inclined surface, and are thus returned to the sheath where they fall down.

The lower surface of said first conduit can on the other hand be inclined downward towards the interior of the sheath in its zone adjacent to said sheath.

This measure also aims to prevent the penetration into the first conduit of heavy products since these would be brought by sliding on the lower surface of this first conduit to fall back into the sheath.

Said means for stopping the sheet materials preferably comprises a receiving member such as a grid or a wire mesh disposed in a plane transverse to the air flow at the end of said first duct and movable in this plane of the position where it is located across said flow at positions where it is away from this flow.

Thus the sheet materials are, at the outlet of the first duct, pressed against the receiving grid which is across the air flow and then are brought by the movement of this grid outside the flow at a point. where they detach themselves from the grid.

According to another aspect of the invention, it also relates to a device for the separation of sheet materials in a waste treatment installation, characterized in that it comprises a first conduit, means for driving in this first conduit a flow of air charged with said sheet materials, and a receiving member such as a grid or a wire mesh disposed in a plane transverse to the air flow at the end of said first conduit and movable in this plane from the position where it is across said flow to positions where it is away from this flow.

In all cases, said receiving member is preferably constituted by one of the strands of a mat of grids rotating in front of the end of said first duct.

In a particular embodiment of the invention, said receiving member is substantially vertical and is arranged to move down from the position where it is across said flow to the positions where it is away from this flow .

Thus the sheet materials which are pressed against the grid are driven downwards then fall from the grid when the grid portion on which they are located is brought out of the air flow.

An air collection box can be placed behind said receiving member, said box having a first opening substantially facing said end of the first conduit.

This box can also have a second opening to which is connected a second conduit for the evacuation of the air freed from said sheet materials.

In a particular embodiment of the invention, said receiving member is disposed inside a second substantially vertical sheath, this second sheath constituting the supply sheath of a second mill.

Thus the sheet materials which have been recovered can be ground in order to be further processed, for example to be transformed into combustible pellets.

• - La figure 1 est une vue en perspective d'un dispositif selon l'invention,
• - La figure 2 est une vue à plus grande échelle du caisson de collecte d'air représenté à la figure 1 et.
• - La figure 3 est une vue en coupe selon la ligne 111.111 de la figure 1.

A particular embodiment of the invention will now be described by way of nonlimiting example with reference to the appended schematic drawings in which:

• FIG. 1 is a perspective view of a device according to the invention,
• - Figure 2 is an enlarged view of the air collection box shown in Figure 1 and.
• - Figure 3 is a sectional view along line 111.111 of Figure 1.

The device shown in the drawing generally comprises a supply assembly 1 for waste, for example urban waste, a set 2 for separating sheet materials and grinding of other materials, a set 3 for recovery and grinding sheet materials, and a set 4 of dusting and air recycling.

The assembly 1 comprises a conveyor belt 5 whose upper end is disposed above an endless belt 6 with metal scales provided with blades 7 for the opening of the plastic bags generally used for the collection of urban waste . The endless belt 6 brings the waste to an opening 8 formed in one of the vertical walls of a vertical feed sheath 9 of a hammer mill 10. A stop plate 11, the height of which is adjustable using a member 12 such as a screw and the lower part of which is also provided with opening blades 13, is arranged at the entrance to the orifice 8 above the end of the mat 6.

Thus the waste is brought to this belt 6 where the plastic bags are opened using the blades 7 and 13, after which the waste is poured into the sheath 9 where the heavy materials fall towards the crusher 10.

A fan 14 has its outlet duct 15 which opens into the duct 9 oriented upwards. The fan 14 creates in the duct 9 an ascending air flow which carries the light materials, and more particularly the sheet materials, upwards.

A first suction conduit 16 opens at the upper part of the sheath 9 through an orifice 17 (Figure 3).

A venturi 18 produced for example using angles or folded sheets forms a constriction in the sheath 9 between the supply orifice 8 and the orifice 17 of the duct 16. This venturi 18 has the effect of accelerating the upward air flow which entails the sheet materials.

The duct 16 comprises in its zone adjacent to the sheath 9 an upper surface 19a inclined upwards in the direction of the sheath 9 and a lower surface 19b inclined downwards. Thus heavy products which would be projected into the upper part of the sheath 9 by the action of the crusher 10 could not be entrained in the conduit 16 since they would strike the surface 19a which would return them either directly in the sheath 9 or on the surface lower 19b from which they would slide in the sheath 9 as represented by the arrow 20.

The conduit 16 has its other end which enters a second vertical sheath 21 supplying a second mill 35.

Between these two sheaths, the conduit 16 has a form of venturi in order to accelerate the flow.

Inside the sheath 21 and opposite the end of the conduit 16 is disposed an endless belt 22 produced in the form of a grid and wound on two rollers 23 one of which is motor to drive the grid 22 in a rotational movement. In this movement, the strand of the belt 22 which receives the flow of air from the duct 16 moves downward. The pitch of the grid 22 can for example be of the order of a few centimeters and its forward speed of the order of 2 meters per second.

A box 24 for collecting air is placed in the sheath 21 between the two strands of the grid 22. For greater clarity, this grid 22 has not been shown in FIG. 2 which shows the box 24 in detail.

This box has an opening 25 located opposite the opening 26 at the end of the duct 16, on the other side of the grid 22 which therefore passes between the openings 25 and 26.

The box 24 has in one of its vertical faces adjacent to the face in which the opening 25 is formed, another opening connected to a second duct 27. Thus, the flow of air loaded with sheet materials which arrives through the line 16, enters the box 24 after being discharged of its sheet materials on the grid 22 then leaves the box 24 through the second pipe 27. The sheet materials which are pressed against the grid in the area of the opening 25 are driven down by the movement of this grid and then detach when the portion of the grid on which they are pressed out of the air flow. These sheet materials then fall into the sheath 21 to the crusher 35 where they are shredded.

The conduit 27 opens in a known manner into a cyclone 28 from which it emerges through the axial conduit 29 after being dusted. The dust is collected at the bottom of the cyclone 28 at the valve 30.

The dedusted air is then accelerated by a fan 31 driven by a motor 32 to be returned to a third conduit 33 which opens at the upper part of the sheath 9 through an orifice 34 situated substantially opposite the orifice 17 of the conduit 16.

It is therefore understandable that, thanks to the device of the invention, the fermentable products capable of forming humus are recovered at the outlet from the crusher 10, the non-fermentable or slightly fermentable products at the outlet from the crusher 35 in the form of sheets such as plastics, papers, fabrics, cardboard etc ... using which we can then make combustible pellets, and the dust at the base of cyclone 28.

The sheet materials are separated from the fermentable materials at the level of the sheath 9 where they are entrained upward by the ascending air flow caused by the fan 14. They are then supported by the transverse air flow coming from the orifice 34 of the conduit 33 and moving towards the orifice 17 of the conduit 16 to be brought to the receiving grid 22 which allows their recovery.

Claims (11)

1. A device for separation of sheet material in an apparatus for treatment of refuse, comprising separation means, stop means for the sheet materials, a cyclone (28), a second duct (27) between said stop means and the cyclone, a third duct between the cyclone and the separation means, and a blower (31) for ensuring a flow of air in a circuit formed between the separation means, the stop means, the cyclone, and back to the separation means, through said second and third ducts, characterised in that said separation means comprises a first passage (9), substantially vertical, and means (10, 14) for causing in this first passage an ascending flow of air, in that said device comprises a first duct (16) of venturi shape between said first passage and said stop means to close said air circuit, and in that said first and third ducts open substantially opposite each other on to the upper part of said first passage to cause a transverse flow of air.

2. A device according to claim 1, characterised in that said first passage forms a venturi (18) below the zone into which said first duct opens.

3. A device according to claim 1 or 2, characterised in that the upper surface (19a) of said first duct is inclined upwardly in the direction of the interior of the passage, in its zone adjacent said passage.

4. A device according to any one of claims 1 to 3, characterised in that the lower surface (19b) of said first duct is inclined downwardly in the direction of the interior of the passage, in its zone adjacent said passage.

5. A device according to any one of claims 1 to 4, characterised in that said stop means comprise a receiving member (22) arranged in a plane transverse to the flow of air at the end of said first duct and movable in this plane from a position in which it is across said flow to positions in which it is separated from the flow.

6. A device according to claim 5, characterised in that said receiving member comprises one of the sides of an endless belt forming a grid moving in front of the end of said first duct.

7. A device according to claim 5 or 6, characterised in that said receiving member is substantially vertical and arranged to move downwardly from the position in which it is across said flow to the positions in which it is separated from the flow.

8. A device according to any one of claims 5 to 7, characterised in that an air-collecting enclosure (24) is arranged behind said receiving member, said enclosure having a first opening (25) substantially opposite said end of the first duct.

9. A device according to claim 8, characterised in that said enclosure has a second opening to which the second duct (27) is connected for evacuation of air removed from said sheet materials.

10. A device according to any one of claims 5 to 9, characterised in that said receiving member is arranged inside a second substantially vertical passage (21), the second passage forming the feed passage for a second crusher (35).

Images