EP2346617B1

EP2346617B1 - Apparatus and method for reclaiming material

Info

Publication number: EP2346617B1
Application number: EP09815453.7A
Authority: EP
Inventors: Richard Henry Coulton
Original assignee: Siltbuster Ltd
Current assignee: Siltbuster Ltd
Priority date: 2008-10-06
Filing date: 2009-10-06
Publication date: 2014-04-23
Anticipated expiration: 2029-10-06
Also published as: GB0818262D0; AU2009300912A1; WO2010040993A3; NZ592692A; AU2009300912B2; GB2464140B; GB2464140A; EP2346617A2; WO2010040993A2

Description

The invention relates to an apparatus and method for reclaiming material. More particularly, but not exclusively, the invention relates to a portable apparatus and method that uses a trommel and inclined screw conveyor for separating granular material into 3 size fractions: a relatively coarse fraction, a finer fraction and a fine fraction. Examples of materials that may be treated are contaminated soils, construction materials, waste material from road gullies, soil and waste concrete, but the invention may be applied also to other starting materials.
There are a great many known forms of apparatus incorporating trommels and many of those are portable.
US 1,309,754 describes a portable plant including a trommel at an open end of which a screen grating 11 is provided through which material can fall via a chute into an open end of the trommel. The trommel has a perforated cylindrical wall and formations to the outside and inside of the wall feed material from the open end of the trommel to the opposite end, where a bucket elevator lifts material from the inside of the trommel for subsequent discharge along an elevated chute.
DE 20214115U describes a portable screening machine including a trommel. The machine separates material and has two separate conveyors for conveying material of different sizes after it has been screened.
The present invention seeks to provide an improved apparatus and method.
According to the invention there is provided a portable apparatus for reclaiming material, the apparatus including a container, a perforated platform at one end of the container for receiving material, a first conveyor device below the platform for conveying solid material in a direction towards a first end of a trommel mounted for rotation in the container about an approximately horizontal axis, the trommel having a perforated cylindrical wall with formations on the interior thereof for feeding relatively coarse solid material from the first end of the trommel to the second end, and with formations on the exterior thereof for feeding relatively finer solid material from the first end of the trommel to the second end, and a second conveyor device for raising solid material arriving at the second end of the trommel to a level above the platform and above the axis of rotation of the trommel, the perforated platform being disposed below the top of the trommel, characterized in that the apparatus further includes a third conveyor device, the second and third conveyor devices being arranged for conveying respective ones of the relatively finer and relatively coarse solid material, and in that the apparatus has a first configuration in which material fed along the third conveyor device is discharged onto the second conveyor device and a second configuration in which material fed along the third conveyor device is kept away from the second conveyor device.
By providing the platform for receiving material at a low level it is possible to tip materials into the apparatus from a very wide variety of vehicles and other devices. At the same time, since the second conveyor device raises the separated solid material to a height above the axis of rotation of the trommel, the material can be discharged into a wide variety of apparatus. At the same time, it is possible for the container to be very compact. For example it may have the dimensions of a 20 ft (6058 mm) freight container or may be received within such a container. As will be understood, where reference is made to a 20 ft (6058 mm) freight container that is a reference to a standard ISO container of that size, provided with corner fittings for engagement by load handling equipment, trailers etc.
In this specification "relatively finer" solid material means material that is finer than the "relatively coarse" solid material which may comprise gravel, stones or other larger particles. The "relatively coarse" material may comprise 50% by weight or more of particles having a diameter of more than 2 mm. "Relatively finer" solid material may comprise sand or other particles of similar size. The "relatively finer" solid material may comprise 50% by weight or more of particles having a diameter of less than 2 mm. "Fine" solid material means material that is finer than the relatively finer material and may comprise silt and clay sized particles which may remain suspended in liquid in the bottom of the container. The "fine" material may comprise 50% by weight or more of particles having a diameter of less than 0.06 mm. In the broadest aspect of the invention, the relatively finer material may of course have mixed in it some "fine material".
Whilst reference is made to the apparatus including a "container", it should be understood that this refers to the ability of the apparatus to retain the material being reclaimed within it during its treatment rather than meaning that the whole apparatus is enclosed. Indeed in a preferred embodiment of the invention the apparatus includes an open frame structure.
Preferably a lifting means is provided in the region of the second end of the trommel for lifting the relatively coarse solid material before it passes onto the second conveyor device. The lifting means preferably comprises lifting vanes on the interior of the trommel in the region of its second end. A chute may be provided for feeding relatively coarse solid material lifted by the lifting means onto the second conveyor device.
The second conveyor device is preferably an inclined screw conveyor.
Preferably, the perforated platform comprises a grid. The grid may be formed with parallel bars spaced for example to provide gaps between them in the range of 25 mm to 150 mm, more preferably between 40 mm and 100 mm.
The perforated platform is preferably at a level below the axis of rotation of the trommel. The perforated platform is preferably at a level of less than 1.5 m and preferably less than 1m above the bottom of the container. Such a low level facilitates tipping of material onto the platform. Preferably the perforated platform is disposed in an approximately horizontal plane.
The first conveyor device may be arranged to convey material directly into the trommel or via one or more other devices. In a preferred form of the invention, a lifting device is provided for receiving material from the first conveyor device and lifting it to a higher level before it enters the trommel. A chute may be provided for feeding material lifted by the lifting device into the trommel. The lifting device may, for example, comprise a rotating bucket conveyor, or a screw, belt or chain conveyor. Preferably the axis of rotation of the bucket conveyor is approximately parallel to or coincident with the axis of rotation of the trommel; that enables a compact arrangement to be provided. In a preferred embodiment of the invention described below, the lifting device is fixed to the first end of the trommel, but the lifting device may be separately mounted and may then operate at a different speed. By interposing a lifting device between the first conveyor device and the trommel, the outlet of the first conveyor device may be kept at a low level which further facilitates low level tipping of material into the apparatus.
In the second configuration the second and third conveyor devices may feed material in substantially different directions. The third conveyor device preferably also raises solid material to a level above the platform and above the axis of rotation of the trommel. The third conveyor device may comprise a revolving belt, which may be ridged.
For most applications, in particular, but not exclusively, treatment of waste mixed concrete that has not set, the apparatus preferably further includes a means for introducing water, for example as a spray, onto material in the apparatus. The water introducing means may be provided in one or more regions of the apparatus to add water, for example, to material resting on the platform and/or to add water to material in and/or around the trommel.
The waste material supplied to the apparatus will commonly include water and therefore whether or not a water introducing means is provided the apparatus preferably further includes a liquid outlet, which may be in the form of either a pipe or pump, for removing liquid material from the container.
Water removed from the container is likely to contain a considerable amount of fine material, for example silt. Accordingly, the apparatus may further include a further container for receiving liquid material from the interior of the first mentioned container. The further container may include means for separating fine material from water. Such devices are known per se.
The portable apparatus preferably further includes a drive means for driving the conveyor devices and the trommel. The drive means may be electrically or hydraulically powered and may be inside or outside the container. A plurality of separate drive means may be provided.
According to the invention there is also provided a method of separating material, the method comprising the following steps:

a) feeding material onto a perforated platform in a container of a portable apparatus,
b) conveying solid material that falls through the perforated platform into a first end of a trommel rotating about a substantially horizontal axis in the container,
c) conveying relatively coarse solid material from the first end of the trommel to the second end by virtue of formations on the interior of the trommel,
d) conveying relatively finer solid material passing through the trommel from the first end of the trommel to the second end by virtue of formations on the exterior of the trommel, and
e) conveying solid material arriving at the second end of the trommel to a level above the platform and above the axis of rotation of the trommel, characterized in that the method further includes providing second and third conveyor devices, the second and third conveyor devices conveying respective ones of the relatively finer and relatively course solid material, and in that the apparatus is operated in a first configuration in which material fed along the third conveyor device is discharged onto the second conveyor device or in a second configuration in which material fed along the third conveyor device is kept away from the second conveyor device.

Step b) above preferably comprises the steps of conveying solid material that falls through the perforated platform towards a first end of the trommel, lifting solid material that has been conveyed towards the first end of the trommel, and feeding the lifted material into the first end of the trommel.
Liquid material containing fine material, for example silt, is preferably conveyed from the container to a further container for further separation of solid material.
The method of the invention may be carried out in a portable apparatus taking any of the forms defined above.
The apparatus and method is particularly well suited to treating waste material collected from road gullies.
By way of example certain embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Fig. 1A: is an isometric view in a first direction of a portable apparatus for separating material, the apparatus being shown in a first configuration;
Fig. 1B: is an isometric view in a second direction of the portable apparatus of Fig. 1A, the apparatus being shown in the first configuration;
Fig. 2A: is an isometric view in the first direction of the portable apparatus of Fig. 1A, the apparatus being shown in a second configuration;
Fig. 2B: is an isometric view in the second direction of the portable apparatus of Fig. 1A, the apparatus being shown in the second configuration;
Fig. 3: is a partially cut away isometric view in the second direction of the portable apparatus of Fig. 1A, the apparatus being shown in the first configuration; and
Fig. 4: is a schematic isometric view of a modified form of portable apparatus for separating material.

The portable apparatus shown in Figs. 1A to 3 generally comprises a frame 1 in which a grid 2 having parallel bars with a spacing of 50 mm between adjacent bars and a trommel 3 mounted for rotation about a horizontal axis are provided, and a discharge feed 4 leading to a discharge chute 5. The apparatus shown in the drawing is of open frame construction with closed interior spaces below the grid 2 and the trommel 3 to collect liquid, but
it should be understood that it may have closed sides so that the whole device forms a watertight container.
The grid 2 is provided at one end of the frame and a screw conveyor 12 (see Fig. 3) is provided below the grid 2 for feeding material that falls through the grid to a bucket conveyor 13 from the top of which the material drops onto an inclined chute 14 leading into a first end of the trommel 3, that end being in a middle region of the container. The bucket conveyor 13 and the screw conveyor 12 both rotate about axes parallel to the axis of rotation of the trommel 3. In the particular example described the bucket conveyor 13 is fixed to the first end of the trommel and rotates with the trommel.
The discharge feed 4 contains a screw conveyor 15 for feeding material up to the top of the feed 4, from where it can be discharged through the chute 5 into a skip, stockpile or onto a further conveyance device. In the first configuration of the apparatus, shown in Figs. 1A, 1B and 3, the discharge feed 4 also includes a belt conveyor 16 above the screw conveyor 15 and extending most of the way up the screw conveyor 15. Material travelling up the belt conveyor 16 is dropped from the top of the conveyor into a top portion of the screw conveyor 15.
A drive 17 is used to rotate the screw conveyor 12 below the grid 2, a drive 18 is used to rotate the trommel 3 and the bucket conveyor 13, a drive 19 is used to rotate the screw conveyor 15 and a drive 20 is used to drive the belt conveyor 16.
In use, material is discharged from a lorry onto the grid 2 and falls between the bars of the grid 2. Some liquid material may be removed at this stage and the remaining solid material with some liquid material incorporated is fed towards the trommel 3. The material is then picked up in the scoops of the bucket conveyor 13, lifted close to the top of conveyor 13 until it falls out of the scoop and drops onto the chute 14 and slides down the chute into the trommel 3.
Coarse material (gravel and stone sized material) is fed along the bottom of the trommel 3 to its second end by virtue of inclined vanes 6 on the interior of the trommel while finer material (sand) passes through the openings (not shown) in the cylindrical wall of the trommel and is fed along immediately below the trommel to its second end by virtue of inclined vanes 7 on the exterior of the trommel, a plate 8 below the trommel keeping the finer material in cooperation with the vanes 7.
When the coarse material on the inside of the trommel 3 reaches the second end of the trommel, at the end of the apparatus opposite the grid 2, it is lifted up the side of the interior of the trommel by vanes 9 and dropped onto a chute 21 which feeds it out of the trommel through its open end 30 onto the belt conveyor 16. Similarly finer material carried along the exterior of the trommel is fed to the bottom of the inclined screw conveyor 15. In the arrangement of Figs. 1A, 1B and 3, the finer and coarse materials are then fed upwardly along the feed 4, the material fed up the belt conveyor 16 is discharged at the top of that conveyor onto the inclined screw conveyor 15 and the combined material is then discharged via the chute 5. Liquid from the material drains through the trommel 3 and liquid in the materials raised upwardly in the feed 4 drains back down the feed into a tank 22 below the trommel 3. This liquid has fine material suspended therein and collects in the tank 22. That liquid can be pumped from the tank 22 to another container where the fine suspended solids can be removed from the water in a manner known per se.
For most applications, and especially for reclaiming aggregate and sand from mixed concrete that has not set, it may be desirable to spray water onto the material to be separated. For that purpose, a water supply, preferably a spray, may be provided and may for example spray water onto the material as it is discharged onto the grid 2, and/or when it has passed through the grid 2 and/or when it is in the trommel.
In the embodiment of the invention described above with reference to Figs. 1A, 1B and 3, the coarse and finer material are both fed along the same feed 4, but the apparatus can readily be adapted to provide separate feeds for the coarse and finer material. Figs. 2A and 2B show such an arrangement which uses the same parts as the arrangement of Figs. 1A, 1B and 3 and those parts are referenced by the same reference numerals, but in the case of the arrangement of Figs. 2A and 2B, the belt conveyor 16 is repositioned so as to discharge material that passes up it to the opposite side of the apparatus from the screw conveyor 15.
Fig. 4 is a schematic view of a similar apparatus to that already described and similar parts are referenced by the same reference numerals as in the previous Figures. The description below will be limited to significant differences between the two forms of apparatus.
The apparatus of Fig. 4 is not provided with a bucket conveyor to lift the materials before they enter the trommel 3. Instead the screw conveyor 12 (not visible in Fig. 4) below the grid 2, feeds the solid materials directly into the trommel 3. At the downstream end of the trommel coarse material on the inside of the trommel is lifted up by radial vanes 9 and passes out of the trommel through an opening 10, only partly visible in Fig. 4, into the feed 4. Also radial vanes 11 on the exterior of the trommel 3 lift finer material fed along the outside of the trommel into the feed 4. The screw conveyor 15 in the feed 4 feeds both the coarse and finer material up the feed 4 and the material is then discharged through the chute 5. If desired the feed 4 can be pivotably connected to the main body of the apparatus to allow it to be swung outwardly.
A feature of the apparatus described above with reference to the drawings is that material can be fed onto the grid at a relatively low level (below the axis of rotation of the trommel) while the treated material is discharged at a relative high level (above the axis of rotation of the trommel and above the grid).

Claims

A portable apparatus for reclaiming material, the apparatus including a container, a perforated platform (2) at one end of the container for receiving material, a first conveyor device (12) below the platform for conveying solid material in a direction towards a first end of a trommel (3) mounted for rotation in the container about an approximately horizontal axis, the trommel having a perforated cylindrical wall with formations (6) on the interior thereof for feeding relatively coarse solid material from the first end of the trommel (3) to the second end, and with formations (7) on the exterior thereof for feeding relatively finer solid material from the first end of the trommel (3) to the second end, and a second conveyor device (15) for raising solid material arriving at the second end of the trommel to a level above the platform and above the axis of rotation of the trommel, characterized in that the apparatus further includes a third conveyor device (16), the second and third conveyor devices (15, 16) being arranged for conveying respective ones of the relatively finer and relatively coarse solid material, and in that the apparatus has a first configuration in which material fed along the third conveyor device (16) is discharged onto the second conveyor device (15) and a second configuration in which material fed along the third conveyor device (16) is kept away from the second conveyor device (15).
A portable apparatus according to claim 1, in which a lifting means (9) is provided in the region of the second end of the trommel (3) for lifting the relatively coarse solid material before it passes onto the second conveyor device (15).
A portable apparatus according to claim 2, in which the lifting means comprises lifting vanes (9) on the interior of the trommel (3) in the region of its second end.
A portable apparatus according to any preceding claim, in which the second conveyor device (15) is an inclined screw conveyor.
A portable apparatus according to any preceding claim, in which the perforated platform (2) is at a level below the axis of rotation of the trommel (3).
A portable apparatus according to any preceding claim, in which the perforated platform (2) is at a level of less than 1m above the bottom of the container.
A portable apparatus according to any preceding claim, in which a lifting device (13) is provided for receiving material from the first conveyor device (12) and lifting it to a higher level before it enters the trommel (3).
A portable apparatus according to claim 7, in which a chute (14) is provided for feeding material lifted by the device (13) into the trommel (3).
A portable apparatus according to claim 7 or 8, in which the lifting device comprises a rotating bucket conveyor (13).
A portable apparatus according to claim 9, in which the axis of rotation of the rotating bucket conveyor (13) is approximately parallel to or coincident with the axis of rotation of the trommel (3).
A portable apparatus according to any preceding claim, further including a means for introducing water onto material in the apparatus.
A portable apparatus according to any preceding claim, further including a liquid outlet for removing liquid material from the container.
A portable apparatus according to any preceding claim, further including a further container for receiving liquid material from the interior of the first mentioned container.
A method of separating material, the method comprising the following steps:
a) feeding material onto a perforated platform (2) in a container of a portable apparatus,

b) conveying solid material that falls through the perforated platform (2) into a first end of a trommel (3) rotating about a substantially horizontal axis in the container,

c) conveying relatively coarse solid material from the first end of the trommel (3) to the second end by virtue of formations (6) on the interior of the trommel,

d) conveying relatively finer solid material passing through the trommel (3) from the first end of the trommel to the second end by virtue of formations (7) on the exterior of the trommel, and

e) conveying solid material arriving at the second end of the trommel (3) to a level above the platform (2) and above the axis of rotation of the trommel,
characterized in that the method further includes providing second and third conveyor devices (15, 16), the second and third conveyor devices conveying respective ones of the relatively finer and relatively coarse solid material, and in that the apparatus is operated in a first configuration in which material fed along the third conveyor device (16) is discharged onto the second conveyor device (15) or in a second configuration in which material fed along the third conveyor device (16) is kept away from the second conveyor device (15).
A method according to claim 14, in which step b) comprises the steps of conveying solid material that falls through the perforated platform (2) towards a first end of the trommel (3), lifting solid material that has been conveyed towards the first end of the trommel, and feeding the lifted material into the first end of the trommel.
A method according to claim 14 or 15, in which liquid material containing fine material is conveyed from the container to a further container for further separation of solid material.
A method according to any of claims 14 to 16, in which the method is carried out in a portable apparatus according to any of claims 2 to 13.