DIAPHRAGM WALL CUTTER AND METHOD FOR CUTTING A CUTTING TRENCH IN THE GROUND

Abstract

The invention relates to a diaphragm wall cutter for cutting a cutting trench in the ground, comprising a cutting frame, at least one rotatably drivable cutting wheel which is mounted on an lower side of the cutting frame, a suction nozzle, which is arranged in the region of the at least one cutting wheel and is provided with at least one suction opening, and a suction pump which is configured for suctioning slurry from the cutting trench during cutting via the suction nozzle, the suction pump being connected to the suction nozzle via a suction line. According to the invention, it is provided that at least one filling port is provided for filling the suction pump and the suction line with a liquid when the suction line is shut-off, wherein the suction line and the suction pump are filled with liquid for starting the suction pump.

Claims

1. Diaphragm wall cutter for cutting a cutting trench in the ground, comprising a cutting frame, at least one rotatably-drivable cutting wheel which is mounted on a lower side of the cutting frame, a suction nozzle which is arranged in the region of the at least one cutting wheel and is provided with at least one suction opening, and a suction pump which is configured for suctioning slurry out of the cutting trench during cutting via the suction nozzle, wherein the suction pump is connected to the suction nozzle via a suction line, characterized in that at least one filling port for filling the suction pump and the suction line with a liquid is provided, wherein the suction line and the suction pump are filled with liquid for starting the suction pump.

2. Diaphragm wall cutter according to claim 1, wherein a shut-off device is provided, by means of which the suction line can be shut-off downwards to the cutting trench, and that the shut-off device comprises a locking element which is mounted in a manner adjustable between a shut-off position and a flow position.

3. Diaphragm wall cutter according to claim 2, wherein the locking element is adjustable, in particular displaceable or pivotable, between the shut-off position and the flow position by means of an actuating drive.

4. Diaphragm wall cutter according to claim 2, wherein the locking element is arranged on the suction nozzle or on the suction line.

5. Diaphragm wall cutter according to claim 2, wherein the shut-off device comprises at least one closing cover which can be loosened when the suction pump starts up.

6. Diaphragm wall cutter according to claim 5, wherein the at least one closing cover is configured as a one-way element which can be released by extraction when the suction pump starts up.

7. Diaphragm wall cutter according to claim 5, wherein the closing cover is formed with a degradable material, in particular a biopolymer plastic.

8. Diaphragm wall cutter according to claim 1, wherein the filling port is arranged at or above the suction pump.

9. Diaphragm wall cutter according to claim 1, wherein a filling pump is provided, through which a defined quantity of liquid can be supplied for filling.

10. Diaphragm wall cutter according to claim 1, wherein liquid can be supplied into the suction pump and the suction line prior to start-up of the suction pump, when the suction line is open downwards, in a quantity such that said line and pump are filled for starting the suction pump.

11. Diaphragm wall cutter according to claim 10, wherein a control device is provided, which is configured to stop filling when the suction pump is started.

12. Diaphragm wall cutter according to claim 11, wherein the control device directly controls the filling pump and/or a valve device at the filling port.

13. Diaphragm wall cutter according to claim 1, wherein a display device is provided, which displays a filling state of the suction pump.

14. Method of cutting a cutting trench in the ground by means of a diaphragm wall cutter according to claim 1, wherein that the suction pump and the suction line are filled with a liquid via the filling port before the suction pump is started.

15. Method according to claim 14, wherein a guide trench is created, which is filled with slurry, and that the diaphragm wall cutter is inserted into the guide trench for cutting, wherein the cutting operation is started even before the suction pump is completely immersed in the slurry.

16. Method according to claim 14, wherein that the suction line is shut-off downwards to the cutting trench by means of a shut-off device prior to the start of cutting, and that the shut-off device is opened when said device is immersed in the slurry, wherein the suction line is filled with liquid.

17. Method according to claim 14, wherein that the shut-off device is opened when the suction pump has reached a rotational speed required for suctioning or built-up a negative pressure required for extraction.

18. Method according to claim 14, wherein that liquid is supplied into the suction pump and the suction line by means of a filling pump, when the suction line is open downwards, in a quantity such that the suction pump and the suction line are filled when the suction pump is started.

Description

[0039] The invention is further described below with reference to a preferred exemplary embodiment, which is shown schematically in the drawings. The drawings show in:

[0040] FIG. 1 a schematic side view of a diaphragm wall cutter according to the invention;

[0041] FIG. 2 a schematic illustration at the beginning of creating a cutting trench according to a method according to the invention;

[0042] FIG. 3 a schematic side view of the diaphragm wall cutter of FIG. 2 at the time of creating the cutting trench according to the invention;

[0043] FIG. 4 a schematic side view of the diaphragm wall cutter of FIGS. 2 and 3 during further sinking of the cutting trench;

[0044] FIG. 5 an enlarged schematic cross-sectional view through a suction nozzle according to a further embodiment of a diaphragm wall cutter according to the invention; and

[0045] FIG. 6 a schematic connector assembly for operating a diaphragm wall cutter according to the invention.

[0046] According to FIG. 1, a diaphragm wall cutter 20 according to the invention has a cutting frame 22, on the lower side of which rotatably mounted and driven lower cutting wheels 24 are arranged for removing ground material. The preferably box-shaped cutting frame 22 can be suspended from a carrier device, which is not shown, via a suspension cable or guided via a guide rod. For suctioning off cut-off ground material, the diaphragm wall cutter 20 is provided with a suction pump 30 on the cutting frame 22, which is arranged above the lower cutting wheels 24.

[0047] Via a suction line 28 and a suction nozzle 26, which is positioned centrally between the two pairs of cutting wheels 24, cut-off ground material can be suctioned in together with surrounding slurry 16 during cutting. The suction nozzle 26 is provided here with suction openings not shown in FIG. 1. The slurry 16 can be a liquid, in particular water, preferably a cutting slurry provided with a binding agent, in which milled-off ground material accumulates during cutting.

[0048] With the diaphragm wall cutter 20 according to the invention, a shut-off device 40 with a plate-shaped locking element 42 can be arranged at the lower end of the suction line 28 towards the suction nozzle 26. In the illustration according to FIG. 1, the locking element 42, which is in the form of a spool, is in an opening or flow position. The locking element 42 can be displaced by an actuating drive, which is not shown, into a shut-off position in which the locking element 42 shuts off the suction line 28 in a sealing manner downward toward the suction nozzle 26 and which is shown in FIG. 2.

[0049] Via a schematically indicated filling port 50 on the suction pump 30, liquid can be introduced into the suction pump 30 and the suction line 28 when the suction line 28 is shut off, as clearly illustrated in FIG. 2. In a simple manner, filling can be accomplished via a water line hose that is detachably connected to the filling port 50. By having the locking element 42 in the shut-off position, fluid, in particular water or slurry 16, can thus be retained in the suction line 28 and the suction pump 30 at the beginning of the creation of a cutting trench 14 in the ground 12 and thus keeping these components free of air. FIG. 2 illustrates the cutting trench 14 to be created in a dashed line.

[0050] At the beginning of the method according to the invention, a shallow guide trench 18 is first created in the ground 12. The guide trench 18 is configured in such a way, that its depth corresponds approximately to the diameter of the cutting wheels 24. The guide trench 18 can be created by a discrete construction machine, such as an excavator.

[0051] At the start of cutting, it must be ensured that the suction pump 30 does not draw in any air and thus runs dry. To prevent this, the guide or conduct trench 18 is filled with slurry 16. The diaphragm wall cutter 20 is inserted with its lower portion into the guide trench 18 before the start of cutting, wherein the suction nozzle 26 and preferably also the shut-off device 40 with the locking element 42 in the shut-off position are immersed in the slurry 16, as is illustrated clearly in FIG. 3.

[0052] In this process, a cavity within the suction nozzle 26 may fill with slurry 16 from the guide trench 18, wherein air in the suction nozzle 26 is largely displaced by the slurry 16.

[0053] In this initial position according to FIG. 3, the cutting wheels 24 can now be induced in rotary motion for removing ground material. Simultaneously with or timely to this, the shut-off device 40 can be actuated so that the locking element 42 is returned from the shut-off position back again to the opening or flow position. Simultaneously with or promptly to the resetting of the locking element 42, the suction pump 30 can be actuated so that it suctions in slurry 16 from the forming cutting trench 14 together with milled-off ground material and discharges it upwardly via an upper discharge line 32. In particular, before the shut-off device 40 is opened, the suction pump 30 is started. If a required negative pressure is established above a certain rotational speed of the suction pump 30, the shut-off device 40 can be opened. After a constant circulation of liquid has been achieved, the cutting operation can be started.

[0054] The diaphragm wall cutter 20 can now be sunk in this position until the desired final depth of the cutting trench 14 is reached. After an end of the suction and the rotational driving of the cutting wheels 24, the locking element 42 can be returned to the shut-off position so that the diaphragm wall cutter 30, after the retraction from the cutting trench 14, can then be inserted into a guide trench for the creation of another cutting trench at a new cutting location.

[0055] As an alternative or in addition to the shut-off device 40 with the adjustable locking element 42, the existing suction openings 27, which preferably have a circular diameter, can each be closed on the suction nozzle 26 by means of a closing cover 44, preferably made of a rubber material, as shown in FIG. 5. With this arrangement, an interior space or cavity of the approximately wedge-shaped suction nozzle 26 can also be filled with liquid before cutting is started. Thus, there is practically no air left in the area of the suction pump 30, the suction line 28 and the suction nozzle 26. This permits particularly considerate operation of the suction pump 30.

[0056] When the suction pump 30 is started up, the suction pressure is adjusted so that the closing covers 44 detach from the suction openings 27 and are suctioned-off together with slurry 16.

[0057] According to FIG. 6, a possible circuit arrangement 10 for operating a diaphragm wall cutter 20 according to the invention with a suction pump 30 is shown strongly schematically. At the beginning of the method, the diaphragm wall cutter 20 is placed in a manner known per se into a previously created guide trench 18, which is filled with liquid.

[0058] For normal cutting operation, the suction pump 30 is connected via a line L1 to a treatment unit A for treating the extracted supporting liquid, wherein cutting particles can be separated from the supporting liquid in the treatment unit A in a defined manner. By means of a pump P, the treated supporting liquid is returned again to the guide trench 18 or the created trench via a line L2 and L4 in normal cutting operation.

[0059] For performing the method according to the invention, an intermediate line L3 is connected in-between line L1 and L2. For filling the system, a first control valve V1 in line L1 can be closed and a second control valve V2 on line L2 can also be closed. This allows supporting liquid to be directed to the suction pump 30 on the diaphragm wall cutter 20 via the pump P via the intermediate line L3 with an open control valve V3 via the line L1. In this way, the suction pump 30 and the associated line system can be filled before the suction pump 30 is started. In this state, a further, optionally provided control valve V4 on line L2 can also be open.

[0060] To start the suction pump 30, the control valve V3 in the intermediate line L3 can be closed. At the same time, control valve V1 on line L1 and control valve V2 on line L2 are opened so that the normal supporting liquid circuit can be set immediately when the suction pump 30 starts up.