Patent Grant
7182204
1. Field of the Invention
The invention relates to a method for processing a mixture of material, in particular for processing a mixture of material which contains at least one coarse component in pieces and one fine component, and to an apparatus for performing the method of the invention.
2. Related Art
Material that contains such coarse components as stones, relatively small pieces of rock or the like, as well as a fine component that adheres or sticks to the coarse component depending on its moisture content, is often processed into other products worth using by separating the components of the material from one another. In practice, both the composition of the starting mixture of material and its moisture content vary considerably from one case to another. Furthermore, such materials often stubbornly resist simple separation. If the fine component adheres to the coarse components, the mixture of material cannot be separated in a screening operation. Even with so-called roller grates, the material in many cases cannot be readily separated. The fine component may cause a cake to form that does not pass through the openings between the driven rollers, and so adequate separation of stones and fine material is not achieved. However, if chisels or other profiled features are provided on the individual rollers of the roller grates, these chisels or features being intended to feed the fine component downward between the driven rollers, then problems can arise with the coarse component, that is, the stones or pieces of rock contained. For material separation, washing methods are therefore often employed, which wash the fine component out of the coarse component in the form of a sludge. However, the sludge is usually not re-usable, so that there are high subsequent costs for disposing of it. Moreover, the high water consumption often stands in the way of economical employment of such methods. Finally, only one part of the starting material, such as the coarse part, is actually used.
From German Patent DE 196 27 465 C2, it is known to use so-called bucket separators for separating material. They are embodied on the order of a dredge or excavator bucket, with at least two driven rollers disposed in the bottom of the bucket. Disks and chisels are disposed on the rollers. For material processing, the mixture of material is picked up with this bucket, and the bucket is pivoted such that the material it contains weighs down on the rollers. As a result of their rotations, the rollers let the fine component drop through between them, while the coarse component remains in the bucket separator and can then be tipped out.
It is also known from DE 196 27 465 C2 to add added material to the material picked up by the bucket separator; a defined portion of this added material is for instance taken from an appropriate silo and then rests on the picked-up material in the bucket separator. The added material is fed along with the fine component through the bucket separator and separated from the coarse component. Initially, approximately ⅓ of the picked-up material is fed through the bucket separator without added material. To achieve complete mixing of the added material and the fine component, it is necessary as a rule for the finer material that is discharged from the bucket separator to be picked up again by the bucket and made to pass between the rollers. This operation may have to be repeated several times.
From German Patent DE 199 25 502 C1, a method for recovering oil from drilling sludge and/or oil-containing drilling sludge fractions is also known. In this method, coal dust is added to the drilling sludge. Next, the resultant suspension is mixed, after which the mixture is divided into a lightweight and a heavy fraction of coal dust and oil. The coal dust and oil fraction is then separated out by desorption or extraction.
It is an object of the invention to create a processing method for processing a mixture of material which contains at least one lumpy coarse component and one sticky fine component, where from the two components, a re-usable product is to be produced, and the method is meant to be both rational and largely insensitive to fluctuations in quality of the mixture of material to be processed.
The method of the invention processes the mixture of material continuously. To that end, both the mixture of material to be processed and an added material are delivered, each as a continuous stream of material, to a homogenizing and separating device. This enables the homogenizing and separating device to distribute the added material uniformly in the mixture of material, making the mixture of material separable. For instance, a water-binding added material can be added, to reduce the stickiness of the cohesive component. The uniform distribution of the added material in the mixture of material is thus essential for good separability of the entire coarse component from the entire fine component. Moreover, in this way, not only is the coarse component obtained as a re-usable product, but the fine component provided with added material is also obtained with an adequate degree of homogenization, so that posttreatment of the fine component can be dispensed with. Sludge does not occur. This is particularly due to the fact that no water is admixed with the mixture of material.
In the homogenizing and separating device, a flow equilibrium ensues between the streams of material that are delivered and the streams of material that are carried away. Thus the conditions in the homogenizing and separating device during operation of the system can be adjusted to be essentially constant. These conditions include the quantity of material present in the homogenizing and separating device, its composition, its speed and direction of motion, the moisture content of the mixture, and the composition of the mixture.
In contrast to known methods, the material components forming the mixture can be separated from one another in a single pass through the system and converted into separately re-usable products. Moreover, no unusable wastes, such as sludges or the like, are created.
The homogenizing and separating device has a homogenizing segment that extends from an entrance to an exit. The mixture of material and the added material pass through the homogenizing segment in the same direction. Over the entire length of the homogenizing segment, separation exits branch off, formed for instance by interstices between rotating shafts.
A moisture-regulating material is preferably used as the added material, such as quicklime in powder or granulate form, cement, ash, rock dust, granulates, fibers (cellulose or other fibers), wood chips, wood dust, suspensions such as lime sludge, bentonite, or sealing suspensions, for instance plastic-based. The added materials are preferably selected such that they can better separate the fine and the lumpy components from one another, and that the fine component, once it has been separated from the lumpy component, has the requisite or desired physical properties, such as load-bearing ability or imperviousness.
In a preferred embodiment, the metering of the quantity of added material delivered per unit of time is done either constantly or from time to time on the basis of the water content of the mixture of material to be processed. A moisture measuring sensor can be used for the purpose, connected to a central controller. Alternatively, the moisture can be ascertained by taking samples and then examining them. From the physical properties of the sample (moldability) or directly measured moisture content), it is possible to determine the appropriate quantity of added material, for instance with reference to a table, and input it via an input device to the central controller of the processing system. Alternatively, the system can be such that the ascertained moisture content of the mixture of material is input, after which the central control device determines the requisite quantity of added material from internal calculation rules or tables.
It is furthermore possible for the streams of material to be delivered to the homogenizing and separating device in controlled fashion in such a way that only as much material is delivered as leaves the homogenizing and separating device on the exit side. In this way, fluctuations in the separating speed, for instance resulting from fluctuations in quality of the mixture of material, can be compensated for.
It is preferred that both the mixture of material and the added material be delivered jointly in a single stream of material to the homogenizing and separating device. As a rule, this results in especially good homogenization and mixing of the added material and the fine component. The size of the delivered stream of the mixture of material is regulated, for instance by way of the layer height on a conveyor belt delivering it. In a preferred variant embodiment of the method, the layer height is made approximately as large as the greatest diameter of the pieces that form the lumpy component of the material. This represents the least possible layer thickness for an unimpeded process.
Preferably, a delivery of mixture of material is used in which the layer height of the mixture of material, for instance resting on a conveyor belt and delivered on it, is adjusted to be as slight as possible. The width of the conveyor belt, conversely, can be substantially greater. It is possible for the added material to be applied merely as a narrow strip on the mixture of material. However, it is preferable for it to be applied over the full width, so that to the limits of accuracy of this technical process, the same uniform layer height of the mixture of material, with a uniform covering (layer height) of the added material, is obtained over the full width of the conveyor belt delivering it. This creates the best preconditions for good homogenization and thus also good separating action of the homogenizing and separating device.
An apparatus is further provided for performing the method of the invention having at least one homogenizing and separating device, one material delivery device, and one added material metering device. These devices are embodied such that they each operate continuously; that is, they deliver material and added material to the homogenizing and separating device without pause, and the homogenizing and separating device operates without pause, that is, in a continuous process. In order to obtain an effectively continuous homogenizing and separating process even if material is supplied discontinuously, it is considered advantageous to dispose a roller grate in the supply container. The roller grate enables both delivery of material in a way that is made uniform and the ejection of overly large components of material.
The material delivery device is formed for instance by a belt conveyor and optionally a separator device upstream of it. The material delivery device continuously conveys a stream of a mixture of material even when material is input discontinuously. To adjust the feeding stream, a constant material height on the conveyor belt can be established, for instance via a slide or a screen. The belt conveyor can also be embodied as a weighing conveyor. Preferably, a feed hopper is disposed above the conveyor belt. If it is expected that the mixture of material contains coarse components, then it is considered advantageous to dispose a roller grate in or above the feed hopper, in order to eject all the overly large components at the side. This prevents very coarse components from interfering with the feeding process in the delivery of the mixture of material. Moreover, the roller grate disposed above the belt conveyor acts as a material buffer. Material fed discontinuously and in great quantity onto the roller grate is discharged already relatively uniformly from the roller grate to the belt conveyor of the material delivery device.
It is considered especially advantageous for the roller grate of the material delivery device to be embodied as adjustable in its inclination. Thus the capacity can be adapted to different feed streams and qualities of material. The axes of rotation of the rollers are preferably disposed horizontally, while the conveying direction (horizontally, rising or falling) is intended to be adjustable. The roller spacings are preferably fixed, but can also be set adjustably. The roller spacings can be set to match one another. Instead of the roller grate for ejecting the coarsest component, a splitter or breaker device can be provided, which has at least two parallel shafts that carry wedge elements. The wedge elements are oriented obliquely to the radial direction and obliquely to the circumferential direction and serve to split off the very large components (the coarsest component, that is, stones or pieces of rock whose diameter is greater than the maximum layer thickness on the conveyor belt of the delivery device). Preferably, a splitter device of this kind is set up to limit the maximum particle size to approximately 200 mm, or in other to words to split larger pieces and to convey smaller material unaffected onward.
A roller grate, disk separator or similar arrangement can be used as the homogenizing and separating device. A common feature of all of these is that they have a plurality of shafts that are parallel to one another and are preferably driven to rotate in the same direction. The shafts carry separator elements, such as disks, disks provided with chisels, or nonround elements, for instance elliptical elements. Because of the rotation in the same direction, the shafts and the separator elements define a feeding direction. The mixture of material and the added material are delivered to the beginning of the feed path thus formed. The coarse component is removed on the opposite end of the feed path. This can be done either continuously or discontinuously. A discharge device serves to control this process. The separator elements can be provided with protrusions, such as chisels, pins, fingers or the like. This improves both the separator action and the homogenizing action.
As needed, the apparatus of the invention may have a sensor device, which via a control device controls the size of the added stream of material in proportion to the stream comprising the mixture of material to be processed. This then makes a fully automated mode of operation possible, because the quantity of added material required for optimal separation of the components of the material is metered automatically.
Further details of advantageous embodiments of the invention are the subject of the ensuing description and drawings.
Exemplary embodiments of the invention are illustrated in the drawings.
In
The mixture of material 2 is processed by the processing apparatus 1 in that the coarse component 3 is separated from the fine component 4, indicated on the right in
For constantly mixing the added material 5 with the stream of material 11, a metering device 22 for the added material 5 is disposed above the material delivery device 7. The metering device 22 is embodied such that it outputs a continuous stream of material 23, shown for instance in
At the discharge position 18 of the homogenizing and separating device 12, a discharge device 26 is provided, which serves the purpose of controlled ejection of the coarse component 3 occurring here. The discharge device 26 can for instance be formed by a motor-actuated slide 27 or a flap that opens an exit from time to time and closes it again, under the control of the control device 25. Instead of the slide 27, however, if needed, a open exit can be provided, through which the coarse components 3 that occur here are output constantly. To create a uniform layer height of mixture of material 2 and thus a constant stream of material 11 on the belt conveyor 8, a slide 28 is provided above the belt conveyor 8; this slide is either fixedly set or is separably adjustable either via a motor under the control of the control device 25 or by hand. As
In one embodiment, the slide 28 has a rotatably supported roller 28a on its underside, or a corresponding cylinder. It defines a feed chamber 29 above the belt conveyor 8; this chamber is filled with mixture of material 2 and is constantly refilled with the mixture of material 2. A moisture sensor 32 that is connected to the control device 25 protrudes into this feed chamber, at least in one embodiment. The control device uses the data obtained about the moisture or water content in the mixture of material to meter the appropriate quantity of added material.
In one embodiment, a coarse separator, for instance in the form of a roller grate 30 with driven rollers 31, is provided in or above the feed chamber 29. The roller grate 30 is set or arranged such that overly coarse components 3a of material do not reach the conveyor belt 8 and instead are excluded. To that end, the rollers 31 are disposed at appropriate spacings from one another. These overly coarse components 3a of material are those whose size exceeds the height of the slit defined by the slide 28 and the conveyor belt 8. The roller grate 30 serves to discharge the coarsest components 3a before further handling. Laterally beside the roller grate 30, there is an outlet flap 40, to enable discharging accumulated overly coarse components 3a.
Instead of the roller grate 30 for discharging the coarsest component 3a, a splitter or breaker device 36 may be provided as shown in
A splitter 36 of this kind can also be provided immediately following the roller grate 30, if the coarsest components 3a that have been separated out by the roller grate are to be split and separately processed only intermittently.
The processing apparatus 1 described thus far functions as follows:
For processing the mixture of material 2, this mixture is fed constantly into the feed chamber 29. The belt conveyor 8, forming a constant layer thickness, conveys the mixture of material 2 as a stream of material 11 (
By the circulating action of the shafts 14 and the separator elements 15 connected to them, mixing and thus homogenization already occur in the vicinity of the infeed position 17, in the process of which the added material 5 is intimately mixed in particular with the fine component 4. Along the way from the infeed position 17 to the discharge position 18, the degree of homogenization increases, and as a result a consistency is established that allows a separation of the fine component 4 from the coarse component 3. Accordingly, the mixture 6 comprising fine component 4 and added material 5 is fed through the interstices between the shafts 14 and downward, while the coarse component 3, virtually entirely freed of fine component 4, arrives at the discharge position 18.
Here, it can be discharged continuously, or periodically.
If the separation is to be improved, or if separation is difficult for other reasons, then work can be done discontinuously in part, by periodically or from time to time reversing the direction of rotation of the shafts 14. The belt conveyor 8 can be briefly stopped at those times or can continue to run. By means of the reversal, the material separation can be still further reinforced under some circumstances, especially if the fine component 4 is very cohesive.
As a result of the method described, two re-usable products are produced at the same time, namely the coarse components 3 (stones, gravel, pieces of rock or the like) separated out of the mixture of material, and the fine component 4 in the form of the mixture 6 in which it is mixed with added material 5, such as cement, lime, fibers or other added materials. Disproportionately coarse components 3a are already excluded from the feed bin by the roller grate 30 and discharged separately. They can be used uncomminuted or can be delivered to a comminuting system (such as a rock breaking system). The mixture 6 of suitable added materials 5 can be recycled, for instance as filler material for trenches, pits or ditches or the like.
In a modified embodiment, which is shown in
This type of homogenizing and separating device 12 results in an enhanced transporting action and good cutting action for separating the coarse components 3 and fine components 4 from one another.
In a method for processing mixtures of material which contain a coarse component 3 and a predominantly cohesive fine component 4, both the mixture of material 2 and an added material 5 are delivered in continuous streams of material 11, 23, respectively, to a homogenizing and separating device 12. The homogenizing and separating device 12 serves to mix the added material 5 and the mixture of material 2 uniformly with one another, so as to put the fine component 4 of the mixture of material 2 into a state such that the fine components 4 can be separated from the coarse component 3. As a result of the continuous delivery of mixture of material 2 and added material 5 to the homogenizing and separating device 12, and intimate mixing of the added material 5 and fine component 4 is achieved, so that the separation of the coarse component 3 and fine component 4 can take place directly in the same device. With this method, mixtures of material 2 can be processed without waste in a single method into two re-usable products.
The invention has been described in detail with respect to various embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101 11 300 | Mar 2001 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE02/00826 | 3/8/2002 | WO | 00 | 9/8/2003 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO02/072329 | 9/19/2002 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3812821 | Laycock | May 1974 | A |
| 4297311 | Sherman et al. | Oct 1981 | A |
| 4618414 | Hartan et al. | Oct 1986 | A |
| 6444731 | Memon | Sep 2002 | B1 |
| 20030159975 | Romagnoli | Aug 2003 | A1 |
| Number | Date | Country |
|---|---|---|
| 690 758 | Jan 2001 | CH |
| 196 27 465 | Dec 1996 | DE |
| 0 675 232 | Oct 1995 | EP |
| Number | Date | Country | |
|---|---|---|---|
| 20040091319 A1 | May 2004 | US |
