Electropolishing device

Abstract

Device for electropolishing with: - a first container (20) for receiving an electropolishing medium, wherein this first container (20) has an upwardly facing opening, - at least one component carrier (70) on which parts to be electropolished can be arranged, - a support unit on which the at least one component carrier (70) is arranged, wherein the support unit has a rotary drive by means of which the at least one component carrier (70) can be set into rotary motion about at least one axis, - a positioning device which is configured to bring the support unit into a polishing position in which the at least one component carrier (70) is at least partially inside the first container (20) and into a first raised position in which the at least one component carrier is completely above the first container (20).

Description

[0001] The invention relates to a device for electropolishing according to claim 1.

[0002] Devices for electropolishing (hereinafter also referred to as "electropolishing device") are known in the art and are used for electropolishing parts to be electropolished. The invention relates in particular to an electropolishing device which is designed and suitable for the simultaneous electropolishing of a large number of relatively small parts, such as jewelry rings.

[0003] Such an electropolishing device always has a first container for receiving the electropolishing medium, this container having an upward-facing opening. The electropolishing medium contained in this container during operation typically consists of a liquid phase (an electrolyte) and a multitude of polishing media, usually in the form of small glass beads. The electrolyte can be relatively viscous.

[0004] Furthermore, at least one component carrier is provided on which the parts to be electropolished can be arranged. It is generally customary to provide a plurality of such component carriers, each of which in turn has a plurality of wire clips or the like for hanging the parts to be electropolished. It is also known to provide a rotary drive with which the component carriers can be set in rotation when they are located within the first container.

[0005] It is also known to provide an additional second container arranged next to the first container for receiving a rinsing medium, in particular water, so that at least one component carrier can be transferred from the first container to the second container after the electropolishing process has been carried out. A movable lifting device may be provided for this purpose.

[0006] Based on this, the invention aims to improve such a device.

[0007] According to the invention, a support unit is provided in which a rotary drive for the at least one component carrier (generally, several component carriers are provided) is integrated. A positioning device for this support unit is also provided, which is configured to move the support unit into a polishing position in which the at least one component carrier is at least partially located inside the first container, and into a first raised position in which the at least one component carrier is completely above the first container. Thus, the at least one component carrier can be set in rotation in any position. This has several advantages: Firstly, the same rotary drive can also be used to rotate at least one component carrier in a second container mentioned above, thus improving the rinsing performance without requiring a further rotary drive. In a particularly preferred embodiment, the device also includes such a second container.

[0008] Furthermore, by providing a support unit designed according to the invention, it is also possible to rotate the at least one component carrier during lowering into and / or lifting out of the first container, which in particular enables the provision of an automatically operating rinsing device for any adhering polishing particles.

[0009] Furthermore, a simple arrangement of a protective device can be implemented, which also enables effective extraction of any gases that may be generated during electropolishing.

[0010] Additionally, loading and unloading in an elevated position is facilitated, especially when multiple component carriers are used.

[0011] A further advantage of the arrangement of the rotary drive, which is also located above the first container in the polishing position, is that it allows a displacer to be positioned in the center of the first container, thus reducing the volume of the required electropolishing medium. It is preferable to include such a displacer.

[0012] The rotary drive is particularly preferably designed such that the at least one component carrier can be set into a double rotary motion by it, namely into a rotational motion about its own axis and simultaneously into a rotational motion about a central axis. If several component carriers are provided, which is generally preferred, the rotary drive is preferably equipped such that it sets all component carriers together into identical rotary motions.

[0013] Preferably, the support unit comprises a support plate which carries a rotating element rotatable about the central axis and a ring concentric to this central axis, forming parts of the rotary drive. The component carriers are rotatably mounted on the rotating element and each has a wheel that engages with the ring. This enables a simple, synchronous, "planetary" drive of the component carriers. It is further preferred that the ring is a toothed ring and the wheels are gears that mesh with the toothed ring to create a substantially slip-free engagement. The support plate is preferably arranged on a horizontal support or can be detachably arranged on it.A detachable arrangement has the advantage that the loading of the component carriers can be spatially separated from the rest of the device, which allows for a higher utilization of the device, especially when more than one support plate with component carriers is provided.

[0014] In another preferred embodiment, the rotary drive has a drive motor attached in or to the support unit, so that this drive motor is moved with the support unit, resulting in a simple mechanical design.

[0015] A circulation system for the liquid phase of the electropolishing medium is typically provided. In a particularly preferred embodiment, this system can be used to implement a rinsing device for any polishing media that may be adhering to the medium. This rinsing device can be activated, in particular, when the at least one component carrier is lifted from the first container while being set in rotation by the rotary drive. This allows for the simple and automatic prevention of polishing media being carried over from the first container to the second container. This rinsing device has at least one nozzle that generates an inwardly directed jet when the circulation pump is actuated. Preferably, several such nozzles are provided, which are further preferably outlet openings of a ring line encircling the upper opening of the first container.

[0016] Preferably, the first container is designed as a double-walled structure with an inner and an outer liner. The inner liner has a plurality of preferably slot-shaped openings, an annular gap is provided between the inner and outer liners, and an inlet for the circulation pump is in flow communication with this annular gap. This allows for the circulation of the liquid phase of the electropolishing medium while the polishing media remain in the inner liner. The openings are preferably designed as narrow slots whose width is less than the diameter of the polishing media.

[0017] A direct current source must, of course, be provided. This is preferably part of the device according to the invention. This direct current source is connected to a cathode arranged in the first container, while the component carriers (and thus the parts to be electropolished arranged on the component carriers) are anodically energized by the direct current source. In the case of the preferred double-walled construction of the first container, the cathode is preferably arranged in the annular gap.

[0018] Further preferred embodiments and advantages of the invention will become apparent from the further dependent claims and from the exemplary embodiment now described in more detail with reference to the figures.

[0019] The invention will now be described in detail with reference to an exemplary embodiment and the figures. The figures show: Fig. 1 a first perspective view of the described embodiment of the electropolishing device according to the invention, wherein a support unit of this electropolishing device is in a first raised position and a protective device is in a position raised relative to this support unit, Fig. 2 the in Fig. 1 Shown in a second perspective view essentially of the back of the electropolishing device, Fig. 3 that in Fig. 1 Shown, wherein the protective device is in a position lowered relative to the support unit, Fig. 4 that in Fig. 4 Shown in a top oblique view, where an upper housing part of a horizontal support of the support unit is not shown, Fig. 5 essentially the one in the Fig. 1, Fig. 2, Fig. 3 to Fig. 4 Shown, with the protective device not shown, Fig. 6 essentially a detail of the Fig. 5, Fig. 7 a part of the in the Fig. 5 and Fig. 6 shown, namely an outlet ring, Fig. 8 a part of the first container, namely the outer tub and other elements arranged on it, Fig. 9 essentially a further presentation of the in the Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5 shown in another view, Fig. 10 a further detailed representation, namely essentially a support plate of the support unit and elements which are attached to the underside of this support plate, Fig. 11 the in Fig. 10 shown in a view from below, Fig. 12 again the in Fig. 1 Shown, Fig. 13 again the in Fig. 3 shown, Fig. 14 the in Fig. 13 shown, with the support unit in its polishing position, Fig. 15 that in Fig. 14. Shown, with the support unit in a first raised position (corresponding to that shown in the Fig. 3 and Fig. 13 depicted), Fig. 16 the in Fig. 15 Shown after pivoting the support unit so that it is in its second raised position, Fig. 17 the in Fig. 16 shown, with the support unit in its flushing position, and Fig. 18 an alternative embodiment of the protective device.

[0020] The illustrated embodiment and its components are now described with reference to the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 to Fig. 11 described in more detail. This refers to all Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 to Fig. 11. Referenced.

[0021] The electropolishing device, also referred to as electropolishing device 5, has a base element 10, which in the illustrated embodiment comprises a frame 12 and a casing 14. Two containers, namely the first container 20 and the second container 30, project from the top of this base element 10 into it such that a large portion of these containers is located inside the base element 10. These containers 20 and 30 are each closed by a sealing ring, which is firmly connected to the main body of the respective container, for example, by welding. In the case of the first container 20, this is, as will be seen later, an outer body 21; in the case of the second container, it is the single body, which is referred to as the main body 31. The sealing rings are of identical construction, in particular, they have the same diameter.The first container 20 is designed to hold an electropolishing medium, and the second container 30 is designed to hold a rinsing fluid, such as water. The electropolishing medium often consists of a liquid (albeit viscous) phase and a multitude of polishing media (usually in the form of small spheres, for example, made of glass), which enhance the electropolishing effect. At least the liquid phase is circulated, at least temporarily, for which a circulation pump 100 is used. The second container can be of a relatively simple, single-walled construction, while the construction of the first container 30 is more complex; this will be discussed in detail later. For example, how to... Fig. 1 and Fig. 2. A closure plate (or “lid”) 32 can be provided, by means of which the second container 30 can be covered when it is not currently in use. This is in Fig. 1 shown. Such a closure plate can also be provided for the first container.

[0022] How to particularly the Fig. As can be clearly seen in Figure 2, a vertical support 40 is arranged on the base element 10 (namely on its "rear"). This support is held vertically displaceable on the base element by a guide rail (not shown in detail) attached to the base element. In the illustrated embodiment, the vertical displacement is effected by means of a piston-cylinder unit 42, which is supported by a support plate (also not shown) attached to the base element. Other types of vertical drive would also be possible. By means of a pivot bearing (the head 45 of this pivot bearing can be seen in Figure 2), the vertical displacement is achieved by means of a piston-cylinder unit 42, which is supported by a support plate (also not shown) attached to the base element. Fig. As shown in Figure 3, a horizontal support 50 is arranged at the upper end of the vertical support 40, which, according to the definitions given here, is part of a support unit. This horizontal support can assume two defined end positions with respect to its degree of freedom: a first above the first container and a second above the second container. In the illustrated embodiment, the pivoting between these two positions is performed manually, and a locking mechanism is provided that secures the horizontal support 50 in the respective end position relative to the vertical support 40. In the illustrated embodiment, this is achieved by means of a pre-tensioned pin, which engages in a recess in a sliding plate 46 connected to the vertical support 40 when one of the two end positions is reached. To release the locking mechanism, the pin is pulled out of the recess using a handle 48.In other embodiments, the pivoting between the end positions could be motorized. According to the definitions given here, the vertical support 40 and the pivot bearing form the positioning device for the aforementioned support unit, to which the aforementioned horizontal support 50 belongs. By means of this positioning device, the support unit can thus be moved along two degrees of freedom.

[0023] A plurality of component carriers 70 are arranged on the support unit described above, which can be set into a double rotational movement by means of a rotary drive of the support unit. This rotary drive (which, according to the definitions given here, is part of the support unit) will now be discussed in more detail: A support plate 60 is provided (which, according to the definitions used here, is also part of the support unit), which is rigidly connected to the horizontal beam in at least one operating state. This connection is made by means of a connecting piece 54. In the illustrated embodiment, a quick-release coupling is provided so that the support plate is removable; this is often preferable, but not mandatory. The support plate is disc-shaped and its diameter corresponds to that of the closure plate 32. Furthermore, a connection 61 for a suction hose is provided on the support plate 60.

[0024] A rotating element 65 is arranged on the underside of the support plate 60, which is rotatable about a vertically extending central axis ZA relative to the support plate. The aforementioned component carriers 70 are each attached to this rotating element (which, according to the definitions given here, is part of the rotary drive and thus also part of the support unit) by means of a rotary bearing 74. The rotary bearings lie on a circle around the central axis ZA. Each component carrier 70 has a vertically extending rod 72, supported by one of the aforementioned rotary bearings 74, to which a plurality of wire clips 78 are attached for hanging the elements to be polished, in particular rings to be polished. A gear 76 is non-rotatably connected to the rod 72 of each component carrier 70.These gears 76 are each engaged with a stationary gear ring 62, which is rotationally fixed to the underside of the support plate 60 and whose center is defined by the central axis ZA. In the illustrated embodiment, the gear ring 62 has external teeth; however, providing a stationary gear ring with internal teeth would also be conceivable in principle, even though this is generally not preferred for reasons of space. If the rotating element 65 is now set in rotation, each sub-carrier 70 rotates both about the central axis and about itself. It thus performs a double rotational movement, with the axes of rotation being parallel to each other and extending in the vertical direction. It is essential that this rotational movement can be generated independently of the position of the support unit.

[0025] The rotating element is driven by a drive motor 52, which, in the illustrated embodiment, is located within the horizontal support 50 and is thus integrated into the support unit, forming part of the rotary drive. This drive motor 52 drives (here via a gearbox) a vertically extending drive shaft 53, which extends through the connecting piece 54 that connects the horizontal support 50 to a support plate 60. This drive shaft 53 is rotationally fixed to the rotating element 65, at least in the operating state, and extends around the aforementioned central axis ZA (one could also say that the central axis also defines the geometric axis of this drive shaft). If the support plate 60 is detachable, the drive shaft has a coupling.

[0026] The arrangement of the drive motor 52 in or on the horizontal support 50 will usually be preferred; however, it would also be possible, at least theoretically, to drive the rotating element 65 by means of a flexible drive shaft and to arrange the motor separately from the support unit. In other words, the drive motor 52 will usually be attached in or on the horizontal support 50 and can thus be considered part of the rotary drive in the sense of the definitions given here, but this is not absolutely mandatory.

[0027] How to especially the Fig. 1, Fig. 2, Fig. 3 to Fig. 4. A protective device 80 is provided, which increases occupational safety and also enables effective extraction via the connection 61 in the support plate 60. This protective device 80 has a vertically movable protective wall 81, which forms a slotted hollow cylinder. This movable protective wall 81 can be made, for example, of Plexiglas or another plastic material. The movable protective wall 81 thus has two vertical edges 81a and 81b and a lower edge 81c. The two vertical edges 81a, 81b are connected to the vertical legs 83a, 83b of a U-shaped support element 82 in this embodiment. These two vertical legs 83a, 83b of the support element 82 are connected to each other by means of a horizontal leg 84, which is located above the horizontal support 50. Embodiments without such a horizontal leg are possible.Guides 86a, 86b for the vertical legs 83a, 83b are provided on the horizontal support 50, so that the entire protective device 80, i.e., the support element 82 and the protective wall supported by the support element 82, can be moved vertically relative to the horizontal support 50. The movement is performed manually, for which a handle is provided on the movable protective wall 81. Automatic or semi-automatic movement would also be possible. To secure the protective device 80 in its uppermost position relative to the horizontal support 50, a locking lever 87 is provided on the horizontal support 50. In a locked position, the locking section of this lever engages the lower end of at least one vertical leg and / or the lower edge 81c of the movable protective wall 81. Other locking mechanisms, such as clamping mechanisms, are of course also conceivable.

[0028] The horizontal leg 84 carries at least one stopper (here two stoppers 85), such that the contact of these stoppers 85 with the upper surface of the horizontal support 50 defines the lowest position of the protective device 80 relative to the horizontal support 50. A sensor is preferably provided which detects this lowest position.

[0029] The construction of the first container 20, which is intended to hold the electropolishing medium, will now be described. This first container 20 has a two-part construction and comprises an outer liner 21 and an inner liner 27. Both the inner and outer liners are made of plastic and are electrically non-conductive. The outer liner 21 is closed except for a combined inlet / outlet 25 in the funnel-shaped base of the outer liner 21. The liner is open at the top (according to the definition of a liner), and this opening is laterally enclosed by the aforementioned upper sealing ring 24. Furthermore, the outer liner 21 has spacers 26 for the inner liner 27, which will be described subsequently.

[0030] The aforementioned inner tray has a shell with a multitude of slots 27a, which are dimensioned such that the spheres (or other polishing media) of the electropolishing medium cannot pass through them. As can be seen from the Fig. 5. In addition, larger recesses may be provided in the casing of this inner wall (as can be seen in Fig. 5 (only one of these), which are closed by plugs during operation. These openings allow the inner tub to be removed from the outer tub using a tool. In the center of the inner tub 27 is a central protrusion 28, which acts as a displacement, thereby reducing the volume of the electropolishing medium.

[0031] Between the inner tub 27 and the outer tub 21 is an annular gap RS, and the liquid phase of the electropolishing medium can flow into this annular gap RS through the slots 27a in the inner tub 27. In the region of the upper opening of the first container 20, there is a ring line RL surrounding this opening, which in the illustrated embodiment is formed by an outlet ring 22, the aforementioned upper closing ring 24, and a section of the outer tub 21's casing. However, this is only one possible embodiment of such a ring line. Furthermore, in the illustrated embodiment, an intermediate ring 29 is provided, which extends between the inner tub 27 and the outlet ring 22 and thus, together with the outlet ring 22, closes off the annular gap RS at the top. Both the outlet ring 22 and the upper closing ring 24 each have an L-shaped cross-section with a horizontal leg 22a and 22b, respectively.24a and a vertical leg 22b, or 24b. In the vertical leg 22b of the outlet ring 22 a plurality of outlet openings 22c are provided, which point radially inwards and serve as nozzles.

[0032] The inlet / outlet 25 of the outer tank 21 is connected to the inlet of the circulation pump 100, and the outlet of this circulation pump 100 is connected to the ring line RL by means of at least one supply line 23 (in the illustrated embodiment, two supply lines 23 are provided). When the circulation pump 100 is operating, the liquid phase of the electropolishing medium thus enters the annular gap RS through the slots 27a in the inner tank 27, flows from there to the inlet / outlet 25, and is fed by the circulation pump into the ring line RL, from where it is expelled in several radial jets above the level of the electropolishing medium in the first container towards the center of the inner tank.

[0033] Since the device described above is an electropolishing device, a DC power source must naturally be provided, although this is not shown. This DC power source can, in particular, be arranged in or on the base element 10 and thus form part of the electropolishing device, but this is not mandatory. It would also be possible to supply the necessary DC current from an external DC power source. The cathode connected to this DC power source can, for example (and is also preferred), be provided in the annular gap RS, although this is not shown. In this case, the cathode can, in particular, be ring-shaped. The contacting of the component carriers 70 (and thus of the parts to be electropolished held on the component carriers 70) such that these parts (and necessarily also the component carriers) form the anode is effected via a sliding contact on the aforementioned drive shaft 53. This, too, is not shown in detail.

[0034] The intended use of the electropolishing device 5 described above will now be described with reference to the Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16 to Fig. 17 described.

[0035] Fig. Figure 12 shows an initial state (corresponding to Fig. 1), in which the support unit is in a first raised position, characterized in that the component carriers are located completely above the first container 20. In this state, if provided, the support plate can be arranged with parts (rings) to be electropolished already held on the component carriers, or the component carriers can be equipped with parts to be electropolished in this state.

[0036] In the next step, the protective device 80 is lowered until the stoppers 85 rest on the top of the horizontal support 50 ( Fig. 13) In this state, the lower edge 81c of the protective wall 81 is slightly spaced away from the upper edge of the upper end ring 24. The sensor mentioned above detects this lowered position of the protective device and enables the actuation of the piston-cylinder unit 42. In the next step, the horizontal support 50, and thus the entire support unit, is lowered. During this process, the protective device 80 also lowers a further amount, namely until the lower edge 81c of the movable protective wall 81 rests on the horizontal leg 24a of the upper end ring 24 ( Fig. 14) The lowering preferably takes place with the drive motor 25 engaged, so that the part carriers 70 perform the double rotational movement described above. Furthermore, the circulation pump 100 can be active during this step, whereby the parts to be electropolished are already wetted with the liquid phase of the electropolishing medium, which emerges from the outlet openings 22c.

[0037] The lowering of the support unit occurs until it reaches a lower endpoint where at least the wire clips 78 of the component carriers are located within the first container 20 and thus within the electropolishing medium. This position of the support unit is referred to as the electropolishing position. In this state, the electropolishing step is carried out under the double rotation of the component carriers 70 described above (and, of course, with a DC voltage applied).

[0038] In the next step, the support unit is raised again using the piston-cylinder unit 42 until the first raised position is reached again ( Fig. 15) This lifting takes place with the drive motor 52 and the circulation pump 100 switched on, so that the inward-directed jets rinse away any polishing particles that may still be adhering to the parts or the part carriers 70. Subsequently, the horizontal carrier is pivoted into a second upper position, in which the part carriers 70 are located above the second container 30 ( Fig. 16) This can be done while maintaining the vertical position of the protective device 80. The parts carriers are then lowered into the second container 30 for rinsing. This can also be done with the drive motor 52 switched on. The lowest vertical position of the support unit reached in this process corresponds to the vertical position of the support unit in its polishing position. This lowest position is referred to as the rinsing position.

[0039] How to Fig. 18 removes, the protective wall 81 can be in a Fig.The variant shown in Figure 18 has lower stoppers 89, which rest on the upper end ring 24, 34 in both the electropolishing position and the rinsing position. Reference symbol list 5 Electropolishing device 10 Basic Element 12 frames 14. Cladding 20 first container 21 Outdoor tub 22 Exhaust ring 22a Horizontal leg 22b Vertical leg 22c Exit opening 23 Supply line to outlet ring 24 upper end ring 24a Horizontal leg 24b Vertical leg 25 Entrance / Exit 26 spacers 27 Inner tub 27a Slots in the inner tub 28 central protrusion (displacer) 29 Intermediate ring 30 second containers 31 Main tub 32 Cover plate (“lid”) 34 upper end ring 40 vertical beams 42 piston-cylinder unit 45 Head of the swivel bearing 46 Sliding plate 48 handle element 50 horizontal beams 52 Drive motor 53 Drive shaft 54 Connecting piece (with internal drive shaft) 60 support plate 61 Connection for extraction 62 fixed gear ring 65 rotating element 70 component carriers 72 staff 74 rotary bearings 76 gear 78 wire hangers 80 Protective device 81 movable protective wall 81a,b vertical edges of the movable protective wall 81c lower edge of the movable protective wall 82 Support element 83a, b Vertical leg 84 Horizontal legs 85 upper stoppers 86a, b Guide for vertical beams 87 Locking levers 88 handle 89 lower stoppers 100 Circulation pump RL ring main RS ring gap ZA central axis

Claims

Electropolishing device comprising: - a first container (20) for receiving an electropolishing medium, wherein this first container (20) has an upwardly facing opening, - at least one part carrier (70) on which parts to be electropolished can be arranged, - a support unit on which the at least one part carrier (70) is arranged, wherein the support unit has a rotary drive by means of which the at least one part carrier (70) can be set in rotational motion about at least one axis, - a positioning device which is configured to bring the support unit into a polishing position in which the at least one part carrier (70) is at least partially inside the first container (20), and into a first raised position in which the at least one part carrier is completely above the first container (20). Device according to claim 1, characterized in that it further comprises a second container (30) arranged next to the first container (20) for receiving a rinsing medium and that the positioning device is further configured to bring the support unit into a second raised position in which the at least one part carrier (70) is completely above the second container (30) and into a rinsing position in which the at least one part carrier is at least partially inside the second container (30). Device according to claim 2, characterized in that the positioning device is configured to enable a vertical movement of the support unit and a pivoting movement of the support unit in the horizontal plane. Device according to one of the preceding claims, characterized in that the at least one component carrier (70) can be set into a rotational movement about an own axis and simultaneously about a central axis by the rotational drive. Device according to one of the preceding claims, characterized in that a plurality of part carriers (70) are provided which can be moved together by the rotary drive into similar rotational movements. Device according to claim 5, characterized in that the support unit has a support plate (60) which carries a rotating element (65) rotatable about a central axis (ZA) and a ring concentric to this central axis (ZA), which form parts of the rotary drive, wherein the part carriers (70) are rotatably mounted on the rotating element (65) and each have a wheel which is in operative connection with the ring. Device according to claim 6, characterized in that the ring is a toothed ring (62) and the wheels are gears (76). Device according to one of claims 6 or 7, characterized in that the support unit further comprises a horizontal support (50) to which the support plate (60) is attached or can be attached. Device according to claim 8, characterized in that a protective device (80) having a protective wall (81) is arranged vertically displaceable on the horizontal support (50). Device according to one of claims 6 to 9, characterized in that a connection (61) for a suction device is arranged on the support plate (60). Device according to one of the preceding claims, characterized in that it further comprises a circulation pump (100) for circulating the liquid phase of the electropolishing medium received in the first container (20). Device according to claim 11, characterized in that at least one nozzle in flow communication with the circulation pump is provided in the area of ​​the upper opening of the first container (20) to generate an inwardly directed jet. Device according to claim 11, characterized in that a plurality of nozzles are provided, which are preferably designed as outlet openings (22c) of a ring line (RL). Device according to one of claims 11 to 13, characterized in that the first container (20) is designed as a two-shell container with an inner trough (27) and an outer trough (21), wherein the inner trough (27) is designed with a plurality of preferably slot-shaped openings (27a), an annular gap (RS) is provided between the inner trough (27) and the outer trough (21) and an inlet of the circulation pump (100) is in flow communication with the annular gap (RS).

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