Patent Application
20100068017
The present invention relates to a covering, in particular a pit covering. The present invention relates, further, to a method for operating a covering.
Coverings of the type initially mentioned are used, for example, in reception gutters in the wood-processing industry, for example in paper and cellulose works, where bulk material in the form of wood chips is delivered in large quantities.
In the unloading of bulk material from transporters, in particular from wood chip transporters (motor trucks and/or wagons), considerable quantities of bulk material are expelled per unit time. The bulk material has to be routed swiftly into a pit or into a low-lying reception gutter, without the unloading personnel undergoing any risk of falling or of injury or crushing. Thus, for example in the case of a motor truck with a sliding floor, 90 m3 of bulk material can be unloaded within the shortest possible time and therefore transferred onto the covering.
Since bulk material forms bridges, the bulk material may remain on a statically arranged grid-shaped covering and therefore does not pass through the grid. Such a heap of bulk material then has to be moved in relation to the statically arranged covering grid, for example by a wheeled loader or another aid, so that the bulk material passes through the grid. This is time-consuming and cost-intensive, and the grid may thereby be deformed or damaged.
If the grid has a coarse-mesh configuration, the grid has neither a drive-on nor a walk-on capability. To avoid the risk of an accident, such a grid is covered with a large-area cover plate. This, too, is costly and, furthermore, requires a very considerable amount of space for the cover plate which has to be moved in the horizontal direction over the grid or away from the grid.
There are solutions in which the pits have no grid-shaped covering, that is to say there is merely a pit or a hole. In this case, lateral barriers are provided, which have to be opened or removed before a motor truck or a railroad wagon can be unloaded. If, however, the motor truck is positioned at the pit for unloading and the barrier is removed or lowered, it is no longer possible for an operator to open the tailgate of the motor truck in order to initiate the unloading operation, since the operator can no longer walk behind the motor truck (that is to say, on a non-existent pit covering). It is possible, at most, to open the tailgate of the motor truck when the motor truck is still at a sufficient distance from the pit. In this case, however, bulk material may even fall off from the loading area of the motor truck, and this may make it impossible to carry out the furthermore required positioning or maneuvering of the motor truck at the pit for the effective unloading of the bulk material. In this solution, there is also the risk that the motor truck, a wheeled loader, a vehicle and/or an operator may fall into the pit, and this must be avoided under all circumstances for safety reasons.
Particularly in the paper and cellulose industry, acceptance stations for wood chips to be delivered are designed in such a way that the reception gutters are provided with gratings or oscillating bar grates or barriers. These only partially fulfill the requirements listed below. There is therefore a need for improvement. The requirements to be met by an improved covering are particularly:
The object on which the present invention is based, therefore, is to specify and develop a covering and a method for operating a covering which can solve at least one problem listed above.
The covering according to the invention of the type initially mentioned achieves the above object by means of the features of patent claim 1. Accordingly, the covering according to the invention has moveable elements, at least one marginal region and a movement unit. The elements extend, at least in regions, over the space to be covered and are arranged essentially parallel to one another. The elements are in each case mounted rotatably and/or pivotably relation to the marginal region and can be moved by the movement unit. The elements are dimensioned and arranged in relation to one another such that the covering has a drive-on and/or walk-on capability. Such a covering serves particularly for covering a volume and/or a space. In concrete terms, the covering could be designed in the form of a pit covering. At least one of the elements could be designed in the form of a web.
It was therefore recognized, in the first place, that, with a grid floor having a grid pattern of approximately 250×250 mm, an open area of approximately 70% effective for the flow of bulk material is available. If the grid floor has a grid pattern of approximately 300×300 mm, an open area of even approximately 80% is available.
It nevertheless regularly happens that bulk material transferred onto such a grid floor cannot pass through this, the consequence being that the bulk material forms a heap. According to the invention, however, it was recognized that, for example in one embodiment of a covering according to the invention, an open area of only approximately 30% is sufficient. If the bulk material is transferred onto the elements in a position of rest, as a rule, heap formation is likewise observed. However, as soon as the elements are set in motion, a stable or continuous and mostly sufficient bulk material flow is thereby possible in spite of the relatively small open area. As a result of the pivoting or movement of the elements, a vertical movement of the corresponding parts of the elements which grows with the distance from the pivot axis or axis of movement occurs. This vertical movement is transmitted to the bulk material which is under the pressure of its deadweight and gives rise there to tectonic movements which disrupt or prevent any formations of bridges by the bulk material. The bulk material is positively mobilized. Not least, therefore, a predeterminable bulk material flow can be achieved advantageously by means of the covering according to the invention. Owing to the rotational, pivoting or pendulum movement of adjacent elements, the bulk material is also crushed or cut, thus likewise bringing about a conveyance of the bulk material. The bulk material conveyance caused thereby generally makes a smaller contribution than the bulk material conveyance caused by the vertical movements.
According to a preferred embodiment, the movement unit has at least one drive and at least one transmission element. The elements can be driven in a rotational, pivoting or pendulum movement by the at least one drive via the at least one transmission element. For example, an electric motor with a drive power of approximately 2 kW could serve as a drive. Elements with an overall length of 20 m can be driven thereby. This corresponds to a required drive power of 1 kW per 10 m of element length. The interaction between the elements and the transmission element could be configured such that the rotational, pivoting or pendulum movement of the elements has a deflection angle of up to +/−20 degrees.
Particularly preferably, the movement of the elements takes place by means of a repeated deflection or pivoting of the elements in one direction of rotation as far as a first reversal point. A deflection or pivoting of the elements in the opposite direction of rotation as far as the second reversal point then takes place. This operation is executed repeatedly.
In a particularly preferred embodiment, the elements are moved codirectionally. Accordingly, all the elements are deflected or rotated at the same time in the same direction. It is also conceivable in each case to move adjacent elements contradirectionally, in which case, for example, all even-numbered elements are deflected in one direction and all odd-numbered elements are deflected, virtually in phase opposition, in the direction opposite to this, if the elements are imagined with increasing numbering. It may also be advantageous to move all the elements codirectionally for a predeterminable time interval and in each case to move adjacent elements contradirectionally for a further predeterminable time interval. For this purpose, two transmission means could be provided which, for example, could be driven in each case by a drive. Even only one drive and two transmission means with a gear and with a coupling could be provided, by means of which the two transmission means can be driven in phase or in phase opposition, or only one transmission means can be driven.
The elements could have a T-shaped, triangular, trapezoidal or polygonal cross section. A risk for persons of crushing could emanate from the side edge of a T-shaped element (pendulum bar). This embodiment is therefore less preferable, at least for some applications, because of safety requirements by the covering. A cladding of the critical edge (as shown, for example in
Preferably, the elements are designed in such a way that they withstand the introduction of high static and/or dynamic loads, so that vehicles, wheeled loaders or motor trucks can drive over them completely and/or partially. If the covering is to be designed, in terms of the introduction of loads, in such a way that motor trucks can drive over the covering partially or completely, such a covering should in any event be capable of absorbing an introduction of load of up to 15 t per element (for example, a motor truck axle with a load of 10 t).
According to an advantageous embodiment, an element has a longitudinal direction. The axis of rotation or pivot axis of an element is arranged parallel to the longitudinal direction. Preferably, the axis of rotation or pivot axis is arranged within the cross section of an element. According to this embodiment, therefore, an element is individually mounted rotatably or pivotably, for example by means of a shaft provided at one end region of the element and fastened to the element. This shaft could be mounted rotatably in a bearing of the marginal region.
Most particularly preferably, the elements are designed, arranged and moveable in such a way that at least one longitudinal edge of the surface part facing the bulk material executes at least partially a vertical movement if the elements are moved. To be precise, it was recognized that, by means of such vertical movements of the elements, tectonic movements in the accreted bulk material can be brought about, and the formation of bridges by the bulk material can thereby be disrupted or prevented. A vertical flow of the bulk material can thus be achieved.
According to one embodiment, an element has a surface which faces the bulk material. According to this embodiment, the elements are mounted at the marginal region in such a way that the surfaces of the elements are oriented essentially horizontally if the elements are in a state of rest. As a result, persons can walk on the covering and vehicles can drive on it.
At least one limitation means could be provided, by which the movement of the elements can be limited. For this purpose, a limitation or mechanical stops and/or a positive guide of the movement of the elements by mechanical means could be provided, which limits the movement, particularly a pendulum movement, of the elements to max. +/−25 degrees, preferably to +/−18 degrees. A retention of the elements in the position of rest could also be provided in order to prevent a deflection of individual elements, for example when a motor truck drives over the covering.
In the state of rest of the elements, between two adjacent elements, an interspace of predeterminable width which preferably has a value which lies in a range of between 80 and 150 mm could be provided. The gap width preferably amounts to a minimum of 100 mm, a maximum of 130 mm and, in particular, 110 mm, this being considered as an optimum between the risk of crushing and the risk of a false step. Even values deviating from this may be envisaged and depend, in particular, on the average size and nature of the bulk material which is used in each case and for which the covering is designed.
The surface of the elements which faces away from the space to be covered or faces the bulk material, or the upper region of the elements, could have a width, transversely to the longitudinal direction of the elements, which preferably has a value which lies in a range of between 150 and 250 mm. The width preferably has a value of 200 mm, thus ensuring footstep safety. In concrete terms, the elements could have a length which has a value which lies in a range of between 3000 and 7000 mm.
Preferably, the marginal region has a in particular vertically oriented side cladding which extends over a depth of at least 400 mm from the surface of the elements which faces the bulk material. Such an, if appropriate closed, side cladding of the elements or of the pendulum bars may be expedient particularly for shielding the dimensions of human limbs.
Preferably, the surface of the elements which faces the bulk material has a slip-inhibiting coating or at least one slip-inhibiting means, for example in the form of a stud plate provided on the surface or of a corresponding coating. Thus, for example, the material flow is not significantly reduced by profilings, elevations or obstructions on the top side of the elements. In concrete terms, the profilings could have a height of 10 mm and a width of 40 mm and be designed in the form of marginal strips.
A modular type of construction of a plurality of coverings is possible. To cover a space, at least two coverings are arranged next to one another so that a larger pit area can thereby be covered. As a result, advantageously, a plurality of motor trucks or railroad wagons can be unloaded next to one another and/or simultaneously. The coverings could be separately activated specifically for the situation. Thus, the elements of two coverings arranged next to one another could be moveable synchronously or independently of one another. A plurality of coverings could be arranged in one or more lines or rows arranged next to one another.
According to a preferred embodiments, a control device is provided for activating the moveable elements or the movement unit. The control device could activate the elements as a function of the bulk material applied to the covering, in such a way that the bulk material passes through the covering in a time-optimized or flow-optimized manner or in such a way that a predeterminable vertical volume flow of the bulk material passing through the covering can be achieved. Different program flows or activation flows could therefore be stored in the control device and could be retrievable as required.
Preferably, the area of the covering or the width of the interspaces between the elements is measured or dimensioned in such a way that a throughput with a vertical flow on average of 1 m/min is consequently possible or ensured. If, for example, the pivot angle of the elements amounts to only +/−14 degrees, the covering has a better or safer walk-on capability during a movement of the elements. Smoother running is obtained, and the bulk material throughput is not markedly lower than in the case of an angular movement of, for example, +/−18 degrees. In a concrete exemplary embodiment, the vertical flow achieved amounted to 0.8 m/min. The control device could therefore activate the movement of the elements in such a way that a predeterminable, preferably essentially constant volume flow of the bulk material passes through the covering.
The frequency of movement of the elements could have a predeterminable value. This value could amount, for example, to 1 Hz or could lie in a range of 0.1 Hz to 3 Hz. Fixing this value could depend on the type and nature of the bulk material to be processed. As a rule, the frequency of movement of the elements will have a constant value which remains unchanged while the covering is in operation. It could nevertheless be advantageous if the frequency of movement of the elements is variable.
Preferably an operating element is provided, by means of which the movement of the elements can be started, stopped and/or activated in at least two operating modes. The operating element could be designed in the form of a footswitch or in the form of a preferably mobile remote control.
A positive attainment of the planar position of the elements in the event of a stopping of the drive could be provided by means of control measures, if, for example, a plant operator actuates an emergency off device (for example, on the operating element). The elements are accordingly oriented with their upper face horizontally.
Bulk material coming under consideration is, in particular, all types of coarse and inhomogeneous bulk materials. In particular, the bulk material may be biomass or wood chips. The geometric and/or other properties of the covering could therefore be adapted to special features for the use of the covering for biomass or woodchips as bulk material.
According to a most particularly preferred embodiment, the elements are arranged level with the ground. Accordingly, the marginal region and a side cladding possibly provided must be arranged below or flush with the surface of the region around the covering. Arranging the elements level with the ground advantageously makes it possible for a motor truck or a wheeled loader to drive over the covering. The covering is accessible for persons in a simple way, and they can walk on it.
In terms of the method, the object initially mentioned is achieved by the measures of claim 26. Accordingly, a method for operating a covering, in particular for operating a pit covering, is defined. The covering comprises moveable elements, at least one marginal region and a movement unit. The elements extend, at least in regions, over the space to be covered and are arranged essentially parallel to one another. The elements are in each case mounted rotatably and/or pivotably in relation to the marginal region and can be moved by the movement unit. The elements are dimensioned and arranged in relation to one another in such a way that the covering has a drive-on and/or walk-on capability. Bulk material is transferred onto the covering, and, for the discharge or passage of the bulk material through the covering, the elements are set in motion.
The method according to the invention is suitable particularly for operating a covering according to one of claims 1 to 25, and therefore, to avoid repetition, reference is made to the preceding part of the description with regard to the relevant device features. In this case, the method steps required for operating the covering can be inferred by a person skilled in the present field from a knowledge of the disclosure content of the preceding part of the description.
A predeterminable or desired bulk material flow can be achieved particularly by means of a suitable setting of the pivot angle and/or of the frequency of movement of the elements. These could also be varied during operation.
Conventionally, an operation to unload a motor truck loaded with bulk material takes place as follows:
In summary, some advantages of the covering according to the invention are listed below:
There are, then, various possibilities for advantageously implementing and developing the teaching of the present invention. In this respect, reference is to be made, on the one hand, to the patent claims coming after patent claim 1 and, on the other hand, to the following explanation of the preferred exemplary embodiments of the invention by means of the drawing. In conjunction with the explanation of the preferred exemplary embodiments of the invention by means of the drawing, generally preferred refinements and developments of the teaching are also explained. In the drawing:
a shows a diagrammatic illustration of individual elements of a covering of a first exemplary embodiment according to the invention, the elements being in a first angular position,
b shows the elements from
c shows the elements from
d shows the elements from
a shows a diagrammatic illustration of a sectional view of a second exemplary embodiment of a covering according to the invention,
b shows a detailed sectional view of an element of the exemplary embodiment according to
a shows a diagrammatic illustration of a sectional view of a third exemplary embodiment according to the invention of a covering, and
b shows a top view of the covering according to
Identical or similar components are identified in the Figures by the same reference symbols.
a shows individual elements 1 of a covering of a first exemplary embodiment according to the invention in a sectional view. The elements 1 are in a first angular position. The elements 1 have a T-shaped cross section. Reference symbol 2 shows the axis of rotation or pivot axis of the element 1 which runs perpendicularly with respect to the drawing plane. The elements 1 according to
a shows a diagrammatic illustration of a sectional view of a second exemplary embodiment of a covering 5 according to the invention. In the covering 5, only three elements 1 are arranged next to one another. Two adjacent elements 1 have in this case a spacing Z of 100 mm. The elements 1 are shown in
The element 1, shown, enlarged, in a sectional view in
a shows, in a sectional view, a diagrammatic illustration of a third exemplary embodiment of a covering 5 according to the invention. The seventeen elements 1 are of essentially triangular design in this exemplary embodiment. The elements 1 are driven or moved via a strut 14 with the aid of a transmission means 11 (to be precise, a strut to which the elements 1 are in each case fastened rotatably at their lower region) by the movement unit 12 which has an electric motor and a step-up gear. The covering 5 according to
b shows the covering 5 from
It is shown in
In conclusion, it may be pointed out most particularly that the exemplary embodiments dealt with above serve merely for describing the claimed teaching, but do not restrict this to the exemplary embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 016 349.7 | Apr 2007 | DE | national |
| 10 2007 024 016.5 | May 2007 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP08/53969 | 4/3/2008 | WO | 00 | 5/29/2009 |
