HYDRAULIC GRINDING BALL FEED AND DISCHARGE FOR AGITATOR BALL MILLS

Abstract

Method for introducing auxiliary grinding bodies (12) into a stirred ball mill (10) and for removing auxiliary grinding bodies (12) from a stirred ball mill (10), characterized in that the auxiliary grinding bodies (12) are transported into and out of the stirred ball mill (10) via a closed circuit by means of a hydraulic conveying medium (16), wherein the auxiliary grinding bodies (12) are conveyed into and out of the grinding container (11) via the grinding material inlet (30).

Description

[0001] The present invention relates to a method for hydraulic grinding ball supply and removal in agitator ball mills.

[0002] German patent DE 37 27 863 C1 discloses an agitator mill with a feed pipe for the grinding media. The grinding vessel contains a rotary agitator and, surrounding it, a grinding chamber that can be at least partially filled with grinding media and material to be ground. A feed pipe, through which grinding media are fed from the outside to a central area of ​​the grinding vessel while the agitator is running, opens into a cavity in the agitator. A substantially radial outlet opening in the agitator is connected to the grinding chamber. This enables a rapid supply of grinding media.

[0003] German patent DE 39 02 689 C1 discloses a device for introducing auxiliary grinding media into mills, particularly agitator mills. A housing connected to a grinding container contains a conveying chamber that can be connected to a grinding chamber in the grinding container. Auxiliary grinding media are fed into the conveying chamber through an inlet opening in the housing. A conveying member can be moved within the conveying chamber to convey auxiliary grinding media from the inlet opening through an elastic closure toward the grinding chamber. The elastic closure has at least one slot that is elongated transversely to the conveying direction of the conveying member and is normally closed, but allows several auxiliary grinding media to pass through side by side under pressure exerted by the conveying member.

[0004] German patent DE 44 32 200 C1 discloses an agitator mill equipped with a separate separator for the grinding material and auxiliary grinding media. The separator has a rotatably driven rotor for separating the auxiliary grinding media from the treated grinding material. The auxiliary grinding media are transported back to the agitator mill with the untreated grinding material. The separator, together with the agitator mill and the connecting lines, forms a closed system.

[0005] The agitator mill disclosed in German patent application DE 103 38 592 A1 comprises a grinding vessel and a rotary-driven agitator arranged therein. A grinding material inlet leads into the grinding chamber, and a grinding material outlet leads from the grinding chamber. The grinding chamber is at least partially filled with auxiliary grinding media. The grinding material outlet also serves as a suction and separation device for the auxiliary grinding media. It comprises a separator for auxiliary grinding media, which has a separation area, into the upper area of ​​which a suction line dipping into the mixture of grinding material and auxiliary grinding media opens. A lock is integrated into the line for the auxiliary grinding media return.

[0006] DE 10 2009 019 501 A1 discloses a device for removing grinding media from a stirred ball mill. This device consists of a multi-part tube that is inserted through the bottom of the grinding vessel into the grinding chamber near the base of the grinding vessel. A flow in the grinding vessel discharges the grinding media from the grinding vessel through openings in the tube via a line. The tube is movably arranged in the stirred ball mill so that the openings are located in the area of ​​greatest grinding media density.

[0007] The prior art thus includes devices and methods that allow dry grinding media to be introduced into a mill. Systems are also known that allow the grinding media and the material to be ground to be removed from a mill together for subsequent separation. A disadvantage of all these devices, methods, and / or systems is that the mill must always be opened to completely remove and / or replace the grinding media.

[0008] The invention is therefore based on the object of creating a method with which the auxiliary grinding bodies can be filled into and / or removed from an agitator ball mill in a time-saving manner and without high mechanical and personnel expenditure.

[0009] This object is achieved by a method comprising the features of claim 1. Further advantageous embodiments can be found in the features of the subclaims.

[0010] The present invention discloses a method for introducing auxiliary grinding media into a stirred ball mill and for removing auxiliary grinding media from a stirred ball mill. According to the invention, the auxiliary grinding media are transported into and out of the stirred ball mill via a closed circuit using a hydraulic conveying medium. The circuit is considered closed even if a closed or an open storage container is used to carry out the method. However, it must be ensured that the conveying medium can always be circulated without the introduction of air and / or other gases. The auxiliary grinding media are conveyed into the grinding container via the material inlet and out of the material inlet.

[0011] During filling, the auxiliary grinding media are held in a storage tank along with the hydraulic conveying medium. A pump draws the hydraulic conveying medium through a grinding container of the agitated ball mill via a first line and a second line. The auxiliary grinding media are either sucked into the grinding container along with the hydraulic conveying medium or forced into the grinding container. Depending on how the pump or the lines are connected to the grinding container and the storage tank, the conveying flow for the auxiliary grinding media is achieved either by suction or pressure. The conveying medium is pumped out of the grinding container at a slightly elevated point and / or through a separating device, whereby the auxiliary grinding media remain in the grinding container.

[0012] For emptying, the hydraulic fluid is pumped from the storage tank via the second line into the grinding tank. The auxiliary grinding media are pumped or pressed from the grinding tank into the storage tank along with the hydraulic fluid via the first line. After reaching the storage tank, the auxiliary grinding media remain there. The hydraulic fluid, however, is circulated until all auxiliary grinding media have been removed from the grinding tank.

[0013] When removing the grinding media from the agitator ball mill, the agitator shaft is temporarily set in rotation. The rotation of the agitator shaft creates an additional flow in the grinding container, which swirls the grinding media and suspends them in the conveying medium. This significantly improves the removal of the grinding media by the flowing conveying medium.

[0014] The hydraulic fluid is always drawn from a settled zone of the storage tank. Drawing from the settled zone is important because no auxiliary grinding media may enter the pump and no air and / or gases may enter the grinding tank. The settled zone is characterized by the absence of auxiliary grinding media. Furthermore, there is little or no flow in the settled zone. In most cases, the settled zone will be an area separated from the storage tank by a wall. The fluid then enters the settled zone either through penetrations or openings in the wall.

[0015] The hydraulic conveying medium is pumped into the grinding vessel through the center of the grinding vessel floor during the filling and / or emptying process. In another embodiment, the hydraulic conveying medium is pumped into the grinding vessel floor below the agitator shaft during the filling and / or emptying process. By introducing the conveying medium below the agitator shaft, it is flushed directly into a bed of auxiliary grinding media located at the bottom of the grinding vessel. This creates additional turbulence among the auxiliary grinding media. This turbulence is very helpful for discharging the auxiliary grinding media.

[0016] During the filling and / or emptying process, the grinding vessel of the agitated ball mill is filled to at least 90%, preferably 95%, with hydraulic conveying medium and / or auxiliary grinding media. The less air and / or other gases present in the grinding vessel, the better the flow can be controlled to ensure the transport of the auxiliary grinding media. Water or another suitable liquid medium can be used as the conveying medium.

[0017] In the following, exemplary embodiments will explain the invention and its advantages in more detail with reference to the attached figures. Fig. 1 shows the filling of grinding aids into a stirred ball mill with a special storage container. Fig. 2 shows the removal of grinding media from a stirred ball mill with a special storage container. Fig. Figure 3 shows the filling of grinding media into a stirred ball mill with a simple storage container. Fig. Figure 4 shows the removal of grinding media from a stirred ball mill with a simple storage container. Fig. Figure 5 shows the removal of auxiliary grinding media from an agitator ball mill, whereby the hydraulic conveying medium is pumped in below the agitator shaft.

[0018] Fig. 1 shows the filling of auxiliary grinding media 12 into an agitator ball mill 10 with a special storage container 14. The storage container 14, in this exemplary embodiment, has a downwardly tapered shape and is provided with a first shut-off device 34 and a second shut-off device 36. The auxiliary grinding media 12 are stored in the storage container 14 together with the hydraulic conveying medium 16. To remove the mixture of auxiliary grinding media 12 and conveying medium 16, a first shut-off device 34 is opened. The pump 20 then conveys the mixture via a first line 22 to the grinding material inlet 30 of the grinding container 11. In the exemplary embodiment described, the mixture is fed to the grinding container via a connecting line 38, whereby the flowing mixture in the first line 22 generates a suction effect, similar to a water jet pump.The pump draws the conveying medium 16 from the agitator ball mill 10 via the second line 24 and pushes it back into the grinding container 11 via the first line 22. This creates a closed-loop circulation. Furthermore, during this filling process, the conveying medium 16 is drawn out of the grinding container 11 via the separating device.

[0019] Fig. Figure 2 shows the removal of auxiliary grinding media 12 from a stirred ball mill 10 with a special storage container 14. When removing the hydraulic conveying medium 16 from the storage container 14, it must be ensured that the removal point 26 for the conveying medium 16 must always be below the conveying medium level 28 in order to avoid sucking in air. For this purpose, the removal point 26 must be positioned by an operator and / or by a frame below the conveying medium level. Once the removal point 26 is correctly positioned, the second shut-off device 36 is opened and the conveying medium 16 reaches the pump 20 via the connecting line 38. The pump 20 conveys the conveying medium 16 through the second line 24 into the grinding container 11. The pumping takes place via the point in the grinding container bottom 32 via the Fig. 1, the conveying medium 16 has been removed. The conveying medium 16 pumped through the grinding container 11 creates a flow through which the auxiliary grinding bodies 12 are discharged via the grinding material inlet 30 of the grinding container 11. The auxiliary grinding bodies 12, together with the conveying medium 16, reach the storage container 14 via the first line 22. In order to completely remove all auxiliary grinding bodies 12 from the grinding container 11, it is necessary for the agitator shaft 13 to be temporarily rotated. This creates an additional flow through which the auxiliary grinding bodies 12 are swirled up in the grinding container 11 and flushed out of it.

[0020] Fig. 3 shows the filling of grinding aids 12 into a stirred ball mill 10 with a simple storage container 14. In comparison to the Fig. 1 and Fig. Unlike the storage container 14 described in Figure 2, it has no shut-off devices, no special shape, and no permanently mounted outlets. Rather, this exemplary embodiment is intended to illustrate that the filling and emptying process can also be carried out using commercially available containers. The grinding bodies 12 and the hydraulic conveying medium 16 are stored in the storage container 14. The pump 20 generates a material flow through which the conveying medium 16 reaches a removal device 40. In the removal device 40, the material flow is diverted into the first line 22. This creates a negative pressure with which the auxiliary grinding bodies 12 are sucked out of the storage container 14. During this process, care must be taken to ensure that the removal point 26 is always below the conveying medium level 28 of the storage container 14, so that neither air nor other gases enter the material flow.The mixture then enters the grinding container 11 via the grinding material inlet 30. The auxiliary grinding bodies 12 remain in the grinding container, the conveying medium 16 is sucked out via an opening or through a separating device (not shown) in the grinding container bottom 32 and circulated.

[0021] Fig. Figure 4 shows the removal of auxiliary grinding media 12 from an agitator ball mill 10 with a simple storage container 14. In this exemplary embodiment, the hydraulic conveying medium 16 is pumped out of a settled zone 18 of the storage container 14 using the pump 20 and flushed into the grinding container 11 via the second line 24. The settled zone 18 is characterized by the fact that only a slight flow and no auxiliary grinding media 12 are present therein. In the settled zone 18, the removal point 26 for the conveying medium 16 is always located below the conveying medium level 28. The inflowing conveying medium 16 flushes the auxiliary grinding media 12 out of the grinding container 11 via the grinding material inlet 30. The auxiliary grinding media 12, together with the conveying medium 16, reach the storage container 14 via the first line 22.In order to completely remove all auxiliary grinding media 12 from the grinding container 11, it is necessary to temporarily rotate the agitator shaft 13. This creates an additional flow, which swirls the auxiliary grinding media 12 in the grinding container 11 and flushes them out.

[0022] Fig. 5 shows the removal of auxiliary grinding media 12 from a stirred ball mill 10, wherein the hydraulic conveying medium 16 passes below the agitator shaft 13 into the grinding container 11. The Fig. The embodiment shown in Figure 5 works in principle the same as in the Fig. 2. The only and most important difference lies in the feed of the conveying medium 16 below the agitator shaft 13. This type of feed creates a stronger turbulence and a more turbulent flow in the grinding container 11 than in the Fig.2. In order to completely remove all auxiliary grinding bodies 12 from the grinding container 11, it is also necessary to temporarily rotate the agitator shaft 13.

[0023] In a further embodiment (not shown) for filling the agitator ball mill 10, the conveying medium 16 is pumped in together with the auxiliary grinding media 12 through a nozzle near the base of the grinding vessel below the agitator shaft 13. The conveying medium 16 exits through an opening, with a separating device upstream of this opening. The auxiliary grinding media 12 remain in the grinding vessel 11.

[0024] The invention has been described with reference to a preferred embodiment. Reference symbol 10 agitator ball mill 11 grinding containers 12 auxiliary grinding bodies 13 Agitator shaft 14 storage containers 16 Pumped medium 18 calm zone 20 pump 22 first line 24 second line 26 Extraction point for hydraulic pumping medium 28 Pumped medium level 30 Grinding material inlet 32 Grinding container bottom 34 first shut-off device 36 second shut-off device 38 connecting line 40 removal device

Claims

[1] Method for introducing auxiliary grinding bodies (12) into a stirred ball mill (10) and for removing auxiliary grinding bodies (12) from a stirred ball mill (10) characterized by that the auxiliary grinding bodies (12) are transported into and out of the agitator ball mill (10) via a closed circuit by means of a hydraulic conveying medium (16), wherein the auxiliary grinding bodies (12) are conveyed into and out of the grinding container (11) via the grinding material inlet (30). [2] Method according to claim 1, characterized by , that ➢the auxiliary grinding bodies (12) are kept in a storage container (14) together with the hydraulic conveying medium (16); ➢by means of a pump (20) the hydraulic conveying medium (16) is sucked / pressed through a grinding container (11) of the agitator ball mill (10) via a first line (22) and a second line (24) and; ➢the auxiliary grinding bodies (12) are sucked / pressed into the grinding container (11) together with the hydraulic conveying medium (16), whereby the auxiliary grinding bodies (12) remain in the grinding container (11). [3] Method according to claim 1, characterized by , that ➢the hydraulic conveying medium (16) is pumped by the pump (20) from the storage container (14) via a second line (24) into the grinding container (11); ➢the auxiliary grinding bodies (12) are pumped with the hydraulic conveying medium (16) via a first line (22) from the grinding container (11) into the storage container (14); ➢the auxiliary grinding bodies (12) remain in the storage container (14) and ➢the hydraulic conveying medium (16) is circulated until all grinding media (12) have been removed from the grinding container (11). [4] Method according to one of claims 1 to 3, characterized bythat the agitator shaft (13) rotates temporarily when the auxiliary grinding bodies (12) are removed from the agitator ball mill (10). [5] Method according to one of claims 1 to 4, characterized by that the hydraulic conveying medium (16) is always taken from a calm zone (18) of the storage tank (14). [6] Method according to claim 5, characterized by that the calmed zone (18) is always kept free of auxiliary grinding bodies (12). [7] Method according to one of claims 1 to 6, characterized by that the hydraulic conveying medium (16) is pumped into the middle of a grinding container bottom (32) during the filling and / or emptying process. [8] Method according to one of claims 1 to 6, characterized by that the hydraulic conveying medium (16) is pumped in via the grinding container bottom (32) below the agitator shaft (13) during the filling and / or emptying process. [9] Method according to one of claims 1 to 8 characterized bythat during the filling process and / or during the emptying process the grinding container (11) of the agitator ball mill (12) is / is filled at least to 90%, preferably to 95%, with hydraulic conveying medium (16) and / or auxiliary grinding bodies (12). [10] Method according to one of claims 1 to 9, characterized by that water or another suitable liquid medium is used as the conveying medium (16). [11] Method according to one of claims 1 to 10, characterized by that the conveying medium (16) exits the grinding container (11) through a separating device.

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