SCREENING DEVICE AND METHOD FOR ADJUSTING THE TENSION AT A SCREENING DEVICE

Abstract

The invention relates to a method for adjusting the tension of endless and spaced-apart drive elements (1) of a screening device (2), which is used for separating out and removing debris from wastewater (3), wherein the drive elements (1) are moved on a circulating path with the aid of a drive motor (4) of the screening device (2) during the operation of the screening device (2), characterized in that the energy consumption of the drive motor (4) is monitored during the operation thereof, and that the tension is increased as necessary until the energy consumption increases in a previously defined way. Moreover, a screening device (2) for separating out and removing debris from wastewater (3) is provided.

Claims

1. A method for adjusting the tension of a plurality of endless and spaced-apart drive elements of a screening device, which is used for separating out and removing debris from wastewater, wherein the plurality of endless and spaced-apart drive elements are moved under tension on a circulating path with the aid of at least one drive motor of the screening device during the operation of the screening device, the method comprising the following steps: monitoring the energy consumption of the drive motor during the operation of the drive motor to move the plurality of endless and spaced-apart drive elements on a circulating path; monitoring the tension of the plurality of endless and spaced-apart drive elements; and increasing the tension of the plurality of endless spaced-apart drive elements as necessary until the energy consumption of the drive motor increases in a previously defined way.

2. The method of claim 1, wherein the energy consumption is monitored continuously or at regular time intervals over a period of time of multiple days, and wherein the tension is increased when the energy consumption has decreased over the course of the period of time in a previously defined way.

3. The method of claim 1, wherein the tension is reduced again after the energy consumption has increased.

4. The method of claim 3, wherein the tension is reduced again after the aforementioned increase of the energy consumption until the energy consumption decreases again in a previously defined way.

5. The method of claim 1, wherein the tension is increased until the energy consumption reaches or exceeds a first limiting value.

6. The method of claim 1, wherein the tension is reduced until the energy consumption reaches or falls below a second limiting value.

7. The method of claim 1, wherein the tension is reduced until the energy consumption has decreased again to the energy consumption ascertained prior to the increase.

8. The method of claim 1, wherein the tension is increased in a stepwise manner, and, after each increase, the energy consumption of the drive motor is measured and evaluated to determine whether the energy consumption has increased.

9. The method of claim 1, wherein the tension is reduced in a stepwise manner, and, after each reduction, the energy consumption of the drive motor is measured and evaluated to determine whether the energy consumption has decreased.

10. The method of claim 1, wherein the tension is increased and/or reduced manually or with the aid of a tensioning device of the screening device, which is operated with the aid of a controller of the screening device automatically and as a function of the particular measured energy consumption.

11. The method of claim 10, wherein the method for adjusting the tension is carried out automatically at defined time intervals by the controller and with the aid of the tensioning device.

12. The method of claim 1, wherein the method is initiated manually by an operator.

13. A screening device for separating out and removing debris from wastewater, the screening device comprising: at least two endless and spaced-apart drive elements, which are movable on a circulating path with the aid of at least one drive motor of the screening device during the operation of the screening device; a drive motor configured and disposed to drive the at least two endless and spaced apart drive elements in a circulating path; a controller, which is designed for evaluating the energy consumption of the drive motor to determine whether the energy consumption increases in a previously defined way when the tension is increased and/or whether the energy consumption decreases in a previously defined way when the tension is reduced.

14. The screening device of claim 13, wherein the screening device has at least one screening system that includes movable components for removing debris from the wastewater, wherein the movable components are connected to the at least two endless and spaced-apart drive elements, so that the movable components are moved along the circulating path together with the at least two endless and spaced-apart drive elements when the at least two endless and spaced-apart drive elements are moved with the aid of the drive motor.

15. The screening device of claim 13, wherein the screening device includes a signaling unit, with the aid of which an operator of the screening device may be signaled that the energy consumption of the drive motor has increased in a previously defined way after the tension was increased and/or the energy consumption of the drive motor has decreased in a previously defined way after the tension was reduced.

16. The screening device of claim 13, further comprising a tensioning device, which is designed for increasing or reducing the tension of the drive elements.

17. The screening device of claim 16, wherein the tensioning device is operatively connected to the controller, wherein the controller is designed for increasing the tension by actuating the tensioning device within the scope of the adjustment of the tension until the energy consumption of the drive motor increases in a previously defined way, and wherein the controller is designed for subsequently reducing the tension again by actuating the tensioning device until the energy consumption decreases again in a previously defined way.

Description

BRIEF DESCRIPTION OF THE DRAWINGS OF EXEMPLARY EMBODIMENTS

[0049] Further advantages of the invention are described in the following exemplary embodiments, wherein, schematically:

[0050] FIG. 1 shows a side view of a screening device according to the invention,

[0051] FIG. 2 shows a top view of another screening device according to the invention,

[0052] FIG. 3 shows a side view of an alternative embodiment of the screening device shown in FIG. 1, and

[0053] FIG. 4 shows a side view of another screening device according to the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

[0054] It should be noted at the outset that, in figures that show multiple components or sections (such as, for example, cleaning rakes 11) of the same kind, only one of multiple components or sections of the same kind is provided with reference characters for the sake of clarity.

[0055] FIG. 1 shows a screening device 2 (in the form of a so-called screening rake in this case) according to the invention integrated into a sewer 9 for separating out and removing debris 17 in the form of screenings (for example, rocks, branches, etc.), wherein the debris 17 is not shown in all figures. The screening device 2 includes a bar screen 7 protruding into the wastewater 3 obliquely from above, the bar screen 7 being connected, for example, by fastening elements (not shown), to the sewer bed, the lateral wall of the sewer, and/or a frame 15 of the screening device 2.

[0056] Purely for the sake of completeness, it is pointed out that the screening device 2 can also include a bar screen 7, of course, which is installed into the sewer 9 having been rotated by 90° from the view shown in FIG. 1. The wastewater 3 in this case is laterally deflected with respect to the flow direction S and flows through the bar screen 7 obliquely with respect to the actual flow direction S.

[0057] Moreover, the screening device 2 has two drive elements 1, which are arranged one behind the other with respect to the sheet plane shown in FIG. 1, are spaced apart from each other, and are movable in a circulating manner on a circulating path with the aid of a drive motor 4, the drive elements 1 preferably being in the form of drive chains or drive belts, which are connected to one another via multiple intermediate cleaning rakes 11 (only one cleaning rake 11 may possibly also suffice). A top view of a section of the bar screen 7 (cut through) and the drive elements 1 (also shown only in sections) connected to the cleaning rakes 11 is shown in FIG. 2. The cleaning rakes 11 are connected to each of the drive elements 1 by, for example, a mounting 19.

[0058] The drive elements 1 are guided on their circulating path via lateral guides (not shown), wherein the guidance can be located in the upper and the lower return areas, but also in the intermediate areas, in which the drive elements 1 extend in parallel to each other. The return areas are preferably each formed by one lower drive wheel 21 and one upper drive wheel 21, which are mounted at the frame 15 of the screening device 2 via appropriate axes of rotation. The drive wheels 21 (for example, in the form of sprockets) are not shown separately. The drive wheels 21 are located, however, in the area of the lower return mechanism 14 and in the area of the drive motor 4 arranged in the upper area.

[0059] Each cleaning rake 11 includes in turn a plurality of adjacently arranged cleaning prongs 20 (see FIG. 2), which engage into the intermediate spaces 18 of the bar screen 7 when the cleaning rake 11 passes across the upstream-facing front side of the bar screen 7 due to the driving of the drive elements 1 in the conveying direction (in the clockwise direction with respect to FIGS. 1 and 4 and in the counterclockwise direction with respect to FIG. 3).

[0060] The screenings retained by the bar screen 7 (the flow direction of the wastewater extends from left to right in FIGS. 1, 3, and 4) are subsequently captured by the cleaning rakes 11 and their cleaning prongs 20 and conveyed upward. After passing through the upper return area, the screenings enter the area of a screenings discharge 13 and, from there, are discharged to the outside, for example, into a container 10. The cleaning rake 11 is subsequently guided back to the lower return area in the area of the lower return mechanism 14, so that the circuit can start over from the beginning.

[0061] As shown in FIG. 3, the bar screen 7 does not necessarily need to be combed through by the cleaning rakes 11 from the back (as viewed in the flow direction of the wastewater 3). The embodiment shown in FIG. 3 is also conceivable, in which the bar screen 7 is combed through “from the front.” The embodiments shown in FIGS. 1 and 3 represent merely possible embodiments of the screening device 2 according to the invention.

[0062] Another embodiment is shown in FIG. 4. In contrast to the embodiments according to FIGS. 1 and 3, the section that retains the debris 17 of the wastewater 3 is not rigidly arranged in this case, but rather is movably arranged. A plurality of screening elements 12 extending perpendicularly to the sheet plane of FIG. 4 extend between the two drive elements 1, each of the screening elements 12 being connected on both sides to the drive elements 1 and each preferably including an outwardly directed and outwardly curved screening surface section. Alternatively, screening elements 12 can also be used, which include screening surface sections having a flat cross-section or zigzag edges. The screening surface section can be formed, for example, by a metal surface that is appropriately bent and has a plurality of screen openings. The sum of the individual screening surface sections forms the screening surface of the screening device 2.

[0063] During the operation of the screening device 2, the drive elements 1 are each guided on an endless circulating path, for example, via two upper drive wheels 21 arranged in parallel to each other and two lower drive wheels 21 also arranged in parallel to each other, the drive wheels being rotatable about appropriate axes of rotation, wherein the movement of the drive elements 1 can take place with the aid of a drive motor 4 (for example, an electric motor) arranged, for example, in an upper return area.

[0064] During the screening process, the wastewater 3 can pass through the screen openings of the screening elements 12, while the debris 17 carried by the wastewater 3 is retained by the screening elements 12. The screening elements 12 and, thereby, also retained debris 17, after having passed through the upper return area, enter the operating range of a cleaning brush 16, with which the debris 17 is scraped off the screening elements 12.

[0065] The debris 17 removed from the screening elements 12 subsequently reaches the outside via the screenings discharge 13 and can be collected, for example, in an appropriate collection container (not shown).

[0066] In all embodiments, it is now important that the tension of the drive elements 1, i.e., the tension that acts on the individual chain links, is adjusted to a correct value.

[0067] As is to be derived from FIG. 1 by way of example, a tensioning device 5 is provided for this purpose, with the aid of which the spacing between an upper drive wheel 21 and a lower drive wheel 21 (both of which are assigned to a common drive element 1) can be adjusted. For example, it would be conceivable in this context that the two upper drive wheels 21 are connected to the drive motor 4 via a common drive axle. The drive axle is mounted at the frame 15 with the aid of bearings. If the bearings are now rigidly connected, with the aid of threaded spindles at a counter bearing, to counter bearings connected to the frame 15, the bearings, if they are appropriately movably mounted, can be moved due to the movement of the threaded spindles in the direction of the lower drive wheel 21 or in the opposite direction. As a result, it is possible to adjust the spacing of the two upper drive wheels 21 with respect to the two lower drive wheels 21 and, thereby, change the tension.

[0068] Preferably, the tensioning device 5 includes an electric motor, with the aid of which the spacing between the aforementioned drive wheels 21 can be adjusted, for example, by turning the aforementioned threaded spindles.

[0069] Moreover, the screening device 2 includes a controller 6, with the aid of which the drive motor 4 and, if present, the aforementioned electric motor, is/are activatable and deactivatable or is/are regulatable with respect to its/their rotational speed.

[0070] Moreover, the screening device 2 includes one or multiple sensor(s) (not shown), with the aid of which the energy consumption of the drive motor 4 can be detected. For example, the sensor can be designed to detect the amperage of the current reaching the drive motor 4.

[0071] According to the invention, it is now provided that the controller 6 is designed for actuating the tensioning device 5 as a function of the energy consumption of the drive motor 4. In particular, an appropriate chain tensioning mode should be stored in the controller 6, which is activated either manually by an operator or automatically at regular time intervals by the controller 6.

[0072] Within the scope of the chain tensioning mode, the instantaneous energy consumption of the drive motor 4 is now initially registered by the controller 6 during a defined period of time. Thereafter, the spacing between the two drive wheels 21 is increased by a certain extent with aid of the tensioning device 5, as the result of which the tension is increased. Thereafter, the energy consumption is detected again and evaluated to determine whether the energy consumption has increased in a previously defined way as compared to the original energy consumption (for example, whether the energy consumption has reached or exceeded a certain limiting value). If this is not the case, the tension is increased again by a certain amount.

[0073] As soon as the energy consumption has increased in the previously defined way after an increase of the tension, this is an indication for the controller 6 that the tension was increased by too great of an extent. The controller 6 now prompts the tensioning device 5 to reduce the tension again by a certain extent. After the tension has been reduced, the energy consumption is re-evaluated by the controller 6. If the reduction of the tension effectuates a defined reduction of the energy consumption, the adjustment of the tension is ended. On the other hand, if the energy consumption does not decrease in the desired way after the tension has been changed, the tension is reduced again by a certain extent until the desired energy consumption has been reached.

[0074] Alternatively to an automatic adjustment of the tension, it can also be provided that the screening device 2 indicates to the operator, merely with the aid of a signaling unit 8, that the tension must be increased or reduced. Thereafter, the operator changes the tension with the aid of the tensioning device 5, which is then preferably manually actuatable. Subsequently, the energy consumption is re-evaluated, whereupon the controller 6 signals to the operator with the aid of the signaling unit 8 whether the adjustment of the tension has ended, or whether the tension must be further increased or reduced. The tensioning device 5 and the signaling unit 8 are both shown merely in one of the exemplary embodiments. Of course, the tensioning device 5 and the signaling unit 8 can also be present individually or in combination in the remaining exemplary embodiments.

[0075] The present invention is not limited to the represented and described exemplary embodiments. Modifications within the scope of the claims are also possible, as is any combination of the described features, even if they are represented and described in different parts of the description or the claims or in different exemplary embodiments, provided no contradiction to the teaching of the independent claims results.

TABLE-US-00001 List of reference characters 1. drive element 2. screening device 3. wastewater 4. drive motor 5. tensioning device 6. controller 7. bar screen 8. signaling unit 9. sewer 10. container 11. cleaning rake 12. screening elements 13. screenings discharge 14. return mechanism 15. frame 16. cleaning brush 17. debris 18. intermediate space 19. mounting 20. cleaning prong 21. drive wheel S flow direction