Equipment and methods for coating workpieces

Abstract

Device for coating workpieces, comprising a vessel (1) in which a coating bath (2) is located, with at least one lifting and lowering and horizontally movable handling device (3) by means of which at least one workpiece (4, 4a, 4b) can be inserted into and removed from the coating bath (2), with at least one cleaning device (6) which has at least one squeegeeing element (7, 7a, 7b) for removing contaminants from the surface (12) of the coating bath (2), wherein a strip-shaped retaining element (10) extending parallel to the wall of the vessel (1) is arranged in the vessel (1) adjacent to a wall (9b), which is in a retaining position (P R) at the level of the surface (12) of the coating bath (2) a trough-shaped collection area (11) formed by the retaining element (10) with the wall (9b) is defined for the contaminants and wherein the squeegee element (7, 7a, 7b) is movable parallel to the surface (12) of the coating bath (2) from a starting position in direction X onto the collection area (11) in order to bring the contaminants on the surface (12) of the coating bath (2) into the collection area (11), wherein the squeegee element (7, 7a, 7b) is liftable and lowerable and can be moved back below or above the surface (12) of the coating bath (2) in the opposite direction X.

Description

[0001] The invention relates to a device for coating workpieces, comprising a vessel containing a coating bath, at least one lifting and lowering and horizontally movable handling device by means of which at least one workpiece can be immersed in the coating bath, and at least one cleaning device comprising at least one squeegeeing element for cleaning the surface of the coating bath of contaminants. The invention further relates to a corresponding method.

[0002] The coating bath can be a metal bath, for example, a zinc bath for galvanizing metallic workpieces or components. Galvanizing steel parts to protect them from corrosion with a zinc layer is an important application area for the invention. For galvanizing, individual or multiple workpieces or batches of workpieces are lowered or immersed, by means of a handling device, in a generally rectangular vessel containing a bath of liquid zinc at a temperature of approximately 450 °C, and after completion of the galvanizing process, lifted or pulled out of the metal bath.

[0003] During the process, impurities or process residues are created, such as oxides in the form of slag, also called zinc ash, which collect on the surface of the metal bath and form a layer.

[0004] When removing the workpieces from the bath after the coating process is complete, there is a risk that the workpieces will come into contact with the contaminants. This can lead to adhesion, surface defects, and a reduction in quality.

[0005] In practice, it is common to manually remove contaminants from the surface before the workpieces are removed from the zinc bath. This procedure is labor-intensive, cumbersome, and raises concerns regarding occupational safety.

[0006] German patent application DE 25 55 935 A1 relates to a device for metal processing that can scrape slag from the surface of molten metal and remove it from the surface of the melt. This is a motor-driven element used for scraping the surface of the melt and for skimming off the collected slag.

[0007] Utility model DE 20 2007 005 600 U1 relates to a device for removing slag that forms and floats on the surface of a zinc bath during the continuous hot-dip galvanizing of steel strip. The steel strip is continuously fed into a kettle containing molten zinc and, via a deflecting roller inside the zinc kettle, is guided out of the kettle again with slag that forms and floats on the surface of the zinc bath during the galvanizing process. The slag is mechanically removed from the surface of the zinc bath, at least across the entire width of the steel strip and at a defined distance from the steel strip exiting the zinc kettle, either on one or both sides, using at least one scraping device, and is then removed from the zinc kettle.

[0008] Utility model DE 296 21 475 U1 relates to a device in which a lowerable scraper is attached to the front end face of a crossbeam to which workpieces are attached for the purpose of hot-dip galvanizing. This scraper removes impurities such as oxides, zinc ash, or the like from the zinc bath surface in the longitudinal direction of the boiler as the crossbeam is moved into the galvanizing area. This creates a contaminant-free zinc bath surface through which the zinc workpieces can be immersed in the molten zinc by lowering the crossbeam.

[0009] Patent specification KR 10 1 461 739 B1 relates to a device for continuous hot-dip galvanizing, in which the zinc ash accumulating on the zinc bath is conveyed by a blower to the edge of the galvanizing kettle, separated there, and ultimately discharged. The ash is separated by a housing that can be raised and lowered.

[0010] The object of the invention is therefore to further develop a device and a method of the type mentioned at the outset in such a way that impurities can be easily removed from the surface of a coating bath, in particular a zinc bath, before the workpieces are pulled from the surface, in order to avoid damage to the workpieces and loss of quality.

[0011] According to the invention, the problem is solved by a device according to claim 1.

[0012] The subject matter of claim 1 is a device for coating workpieces, comprising a vessel in which a coating bath is located, with at least one lifting and lowering and horizontally movable handling device by means of which at least one workpiece can be inserted into and removed from the coating bath, with at least one cleaning device which has at least one squeegeeing element for removing contaminants from the surface of the coating bath, wherein a strip-shaped retaining element running parallel to the wall of the boiler is arranged adjacent to a wall, which is in a retaining position P R at the level of the surface of the coating bath, a trough-shaped collection area, formed by the retention element and the wall, is limited to contain the contaminants and wherein the peeling element is movable parallel to the surface of the coating bath from a starting position in direction X to the collection area in order to bring the contaminants on the surface of the coating bath into the collection area, wherein the peeling element is raising and lowering and can be moved back below or above the surface of the coating bath in the opposite direction X.

[0013] The device according to the invention is characterized in that a strip-shaped retaining element, running parallel to the wall of the boiler, is arranged in the boiler adjacent to a wall, which is in a retaining position P R At the level of the surface of the coating bath, a trough-shaped collection area, formed by the retention element and the wall, is created to contain the contaminants.

[0014] The contaminants can be moved into the collection area, which is defined by the retention element, using the squeegee. From the collection area, the contaminants can then be easily removed from the surface.

[0015] The removal element can be L-shaped or U-shaped, optionally open upwards or downwards or in the X direction. It can be designed to push the contaminants over the retention element.

[0016] According to the invention, the peeling element can be raised and lowered in order to bring the contaminants into the collection area above or below the retention element and / or to retract the peeling element below or above the surface of the coating bath in the opposite direction X.

[0017] Preferably, the retaining element is removed from the retaining position P R into a lower position P ulowerable below the surface or to an upper position P o It can be lifted above the surface to allow the peeling element to pass into and out of the collection area.

[0018] Preferably, the retaining element is guided inside the boiler at its ends.

[0019] Advantageously, the retaining element can be raised and lowered by means of a linear motor or a swivel arm. The swivel arm has a gripping device at one end and is attached at its other end to a stationary axle. The swivel arm is preferably actuated by means of a mechanical, electrical, or pneumatic drive.

[0020] The cleaning device can have its own drive. Preferably, however, the cleaning device is movable by the handling device. This further development is based on the understanding that the handling device, which is required anyway for transporting the workpieces, can also be used to move or drive the cleaning device. Preferably, the handling device is designed as an industrial robot that has at least one arm.

[0021] In a preferred embodiment, the puller element is held by at least one guide means, wherein the guide means is rod-shaped and engages the puller element from above or is angled and holds the puller element from below.

[0022] Preferably, the cleaning device has a first squeegee element and a second squeegee element arranged one behind the other in direction X at a distance from each other.

[0023] Advantageously, a workpiece holder, attached to the handling device, is located between the first and second puller elements. In this embodiment, the workpiece moves along with the cleaning device.

[0024] The aforementioned problem of the invention is solved process-technically by the method according to claim 10. The advantages of this method correspond to the advantages mentioned in connection with the device.

[0025] The problem is solved by a process for coating workpieces, wherein at least one workpiece is inserted into and removed from a vessel containing a coating bath by means of a lifting and lowering and horizontally movable handling device, wherein contaminants located on the surface of the coating bath are removed from the surface of the coating bath by means of a cleaning device which has at least one scraping element, in order to remove the contaminants from the coating bath. wherein a strip-shaped retaining element running parallel to the wall of the boiler is arranged adjacent to a wall, which is in a retaining position P R at the level of the surface of the coating bath, a trough-shaped collection area, formed by the retention element and the wall, is limited to collect the contaminants. wherein the peeling element is moved parallel to the surface of the coating bath from a starting position in direction X towards the collection area in order to bring the contaminants into the collection area, and wherein the squeegee is raised or lowered to bring the contaminants above or below the retention element into the collection area and to retract the squeegee below or above the surface of the coating bath in the opposite direction X.

[0026] Preferably the retaining element is removed from the retaining position P R in an upper position P o raised above the surface or moved to a lower position P u lowered below the surface of the coating bath to allow the squeegee to pass into and out of the collection area.

[0027] A preferred embodiment is characterized in that the contaminants are removed from the surface of the coating bath by means of a first peeling element and a second peeling element, which are arranged one behind the other at a distance in direction X.

[0028] Preferably, the retaining element is guided at its ends in the boiler and can be raised and lowered by means of a drive.

[0029] Advantageously, the cleaning device is moved by the handling device.

[0030] The invention comprises a method which includes the following process steps: a) Lowering the at least one squeegee element to the surface of the coating bath and moving the squeegee element from the starting position in direction X onto the collection area and squeegeeing the contaminants from a part (A) of the surface of the coating bath; b) Lifting the retaining element from the retaining position (P R ) into an upper position (P o ) above the surface or into a lower position (P u ) below the surface of the coating bath to allow the peeling element to pass into and out of the collection area; c) Lowering the squeegee below the surface of the coating bath and retracting the squeegee in the opposite direction X until below the contaminant-free part (A) of the surface of the coating bath; d) Raising the scraper element to the surface and moving the scraper element in direction X and scraping off the contaminants from another part of the surface; e) Lowering the squeegee below the surface of the coating bath and retracting the squeegee in the opposite direction X to the starting position; f) Moving the retaining element into the retaining position (P R), to retain the contaminants in the collection area; g) Removal of contaminants located in the collection area from the surface of the coating bath.

[0031] Preferably, the coating bath is a zinc bath for galvanizing metallic workpieces.

[0032] The invention is explained in more detail below with reference to preferred embodiments. It shows: Fig. 1 a schematic perspective representation of a first embodiment of the device according to the invention; Fig. 2 a schematic perspective representation of a second embodiment of the device according to the invention; Fig. 3 a schematic perspective representation of a third embodiment of the device according to the invention; Fig. 4 A schematic sketch of a cross-section of a fourth embodiment of the device according to the invention with a retaining element in a retaining position P R ; Fig. 5 a schematic sketch of a cross-section of the fourth embodiment of the device according to the invention with a retaining element in a lower position P u ; Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. 12 schematic diagrams to illustrate the method according to the invention.

[0033] In Fig. Figure 1 schematically sketches a first embodiment of the device according to the invention. This embodiment is a device for galvanizing steel workpieces by immersing at least one workpiece at a time into the zinc bath and withdrawing it from the bath after galvanizing. A coating bath 2, in the form of a zinc bath, is located in a vessel 1. A handling device 3 is designed as an industrial robot with an arm 3a. The type of movements, the sequence of movements, and the paths of the handling device 3 are programmable.

[0034] A workpiece 4 is suspended in the zinc bath 2 by means of a holder 5, which is attached to the arm 3a of the handling device 3. A cleaning device 6 is also attached to the arm 3a; that is, the cleaning device is movable by the handling device 3 because the handling device 3 and the cleaning device 6 form a single unit. This significantly simplifies the design effort for the drive mechanism of the cleaning device 6.

[0035] Depending on the specific requirements, several arms 3a can be arranged side by side along the length of the boiler 1. Each arm 3a holds and moves at least one workpiece 4 and one cleaning device 6.

[0036] In the first embodiment according to Fig. In Figure 1, the cleaning device 6 has a single squeegee 7, which is designed in the form of a strip. Other embodiments are also possible within the scope of the invention. The squeegee 7 is provided with two guide means 8 and 8', which can, for example, be designed as rods. The two guide means 8 and 8' are rigidly connected at one end to the arm 3a and at the other end to the squeegee 7 from above.

[0037] The cleaning device 6 with the scraper element 7 can be raised and lowered by means of the handling device 3 and moved from a starting position on a wall 9a of the vessel 1 in direction X to a trough-shaped collecting area 11 on the opposite vessel wall 9b, parallel to the surface 12 of the zinc bath 2. During this movement, the scraper element 7 partially immerses itself in the zinc bath 2. In the exemplary embodiment, the vessel walls 9a, 9b are designed as longitudinal walls of the vessel 1.

[0038] Adjacent to a boiler wall 9a is a liftable and lowerable retaining element 10 in a retaining position P R The retaining element 10 is located at the level of the surface 12 of the coating bath 2 and defines a trough-shaped collection area 11, which the retaining element 10 forms with the wall 9b, for the contaminants. The retaining element 10 is strip-shaped and runs parallel to and at a distance from the longitudinal wall 9a of the vessel 1 over the entire length of the vessel 1. During the horizontal movement of the squeegee 7 in direction X, the contaminants are pushed to the collection area 11. The retaining element 10 can be moved from the retention position P, for example, by means of a linear drive (not shown). R lowered below surface 12 or raised above surface 12 to allow the puller element 7 to pass into and out of the collection area 11.

[0039] The squeegee 7 can be lowered and moved back to its starting position below the surface 12 of the coating bath 2. Alternatively, it is also possible to raise the squeegee 7 above the surface 12 and move it back.

[0040] At the in Fig. In the second embodiment shown in 2, the cleaning device 6 differs from the one shown in Fig. In the embodiment shown in Figure 1, the component is provided not with one puller element, but with two puller elements 7a and 7b. The other components are equipped with the elements shown in Figure 1. Fig. The components shown in section 1 are identical.

[0041] A first puller element 7a and a second puller element 7b are arranged one behind the other in the direction X, spaced apart from each other. This configuration allows for sequential, staggered cleaning steps. Puller element 7a is connected to two guide elements 8a and 8a', and puller element 7b to two guide elements 8b and 8b'. The guide elements 8a and 8b, which can be designed as rods, for example, are rigidly connected at their other end to the arm 3a of the handling device 3. The holder 5 for a workpiece 4 runs between the two puller elements 7a and 7b.

[0042] The retaining element 10 projects below the surface 12 and partially above the surface 12. This position of the retaining element 10 is also in Fig. 2 shown. In position P o The function of the retention element 10 is to retain impurities that are located between the boiler wall 9a and the retention element 10.

[0043] In the Fig. 1, Fig. 2 to Fig. Figure 3 shows that the retaining element 10 is in a retaining position P R located in the area of ​​surface 12 of zinc bath 2.

[0044] At the in Fig. In the third embodiment shown in 3, the cleaning device 6 differs from the one shown in Fig. The embodiment shown in Figure 1 is illustrated with cranked guide elements 8a and 8b. The other components are shown with the elements shown in Figure 1. Fig. 1 and Fig. The components shown in the two diagrams are identical. The procedure using cranked guide elements is described in connection with Fig. 12 explained.

[0045] In Fig. Figure 4 shows that the retaining element 10 can be raised and lowered by means of a swivel arm 13. The swivel arm 13 has a gripping device 14 at one end and is attached at its other end to a stationary axle 15. The swivel arm 13 can be actuated by means of a mechanical, electrical, or pneumatic drive.

[0046] Fig. Figure 5 shows the liftable and lowerable retaining element 10 in a lower position P u below the surface 12 of the coating bath 2. In this position, the retaining element 10 can be passed over by the squeegeeing elements 7a, 7b during cleaning. The retaining element 10 can be moved from the lower position P by the swivel arm 13. u into the restraint position P R in the area of ​​surface 12 to retain the contaminants.

[0047] The inventive method is described using the Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. Figure 12 explains, which shows in schematic representation various steps of the method according to the invention.

[0048] In Fig. Figure 6 shows that the cleaning device 6, with the first stripping element 7a and the second stripping element 7b, is located in a starting position near a boiler wall 9a inside the boiler 1. The lifting and lowering cleaning device 6 has been lowered until the stripping elements 7a and 7b are partially immersed in the molten zinc. Two workpieces 4a and 4b are suspended in the zinc bath 2 by means of a holder 5. The holder 5 is located between the two stripping elements 7a and 7b.

[0049] On surface 12, there are impurities in the region of length B. Fig. 6 This is essentially the entire surface 12 of the zinc bath. The retaining element 10 is located in the upper position in the area of ​​the surface 12 of the zinc bath 2. The strip-shaped retaining element 10 projects below the surface 12 and partially beyond the surface 12.

[0050] In Fig. Figure 7 shows that the cleaning device 6, with the first scraper element 7a and the second scraper element 7b, was moved from its starting position in direction X to the collection area 11, parallel to the surface 12 of the zinc bath 2. During this movement, the contaminants were scraped from the surface 12 over length A. Contaminants remain on the surface 12, distributed over length B. The workpieces 4a and 4b are moved through the zinc bath during the cleaning step, which can be advantageous for the galvanizing process. Fig. 5, the retaining element 10 is still in the retaining position P Rshown in the area of ​​surface 12 of zinc bath 2.

[0051] In Fig. 8 is, unlike the representations in Fig. 6 and Fig. 7, the retaining element 10 in a lower position P u shown below the surface 12 of the zinc bath 2.

[0052] In Fig. 9 shows that the retaining element 10 is in its lower position P u The cleaning device 6 can pass over or traverse the area below surface 12 with the first squeegee element 7a and the second squeegee element 7b. The length A of the cleaned surface 12 is longer than in Fig. 8 and is essentially half the surface area 12 of the zinc bath 2.

[0053] The first cleaning step is complete, and the cleaning device 6, with its scraper elements 7a and 7b, is lowered below the surface 12 of the zinc bath 2 and retracted. Within the cleaned area A of the surface 12, the cleaning device 6, with its scraper elements 7a and 7b, is raised again. This is in Fig. 10. In a second cleaning step, the squeegee 7b pulls the contaminants in the area of ​​length B towards the collection area 11. Fig. Figure 11 shows that the retaining element 10 is in the lower position P u It has been lowered so that it can be driven over or passed by the puller elements 7a and 7b. Subsequently, the cleaning device 6 is lowered and retracted, and the retaining element 10 is moved into the retaining position P. Rmoved. Subsequently, the contaminants can be easily removed from the surface 12 in the trough-shaped collection area 11, which the retention element 10 forms with the wall 9b.

[0054] In Fig. Figure 12 schematically illustrates the process steps associated with the third embodiment of the device according to the invention ( Fig. 3) be carried out using cranked guide elements.

[0055] Step A shows that the surface 12 is screeded using a screeding element 7 with a cranked guide element 8. The screeding element 7 with the guide element 8 is then in the position shown as 7' and 8'. The retaining element 10 in the area of ​​the wall 9b is in the retaining position P in step A. R shown. Contaminants are already present in collection area 11.

[0056] Step B shows that the retaining element 10 was lifted so that the puller element 7 could pass the retaining element 10 to push further contaminants into the collection area 11.

[0057] Step C shows that the puller element 7 is located behind the retaining element 10 in the collection area 11.

[0058] Step D shows that the retaining element 10 was lowered to retain the contaminants.

[0059] Steps E, F and G show that the peeling element 7 is lowered and moved back to its starting position below the surface of the coating bath.

[0060] Modifications to the invention are readily possible. For example, the peeling elements could be lifted above the surface of the coating bath for retraction and then returned to their starting position above the surface. Reference symbol list 1 boiler 2 Coating bath / zinc bath 3 Handling device 3a Arm 4 workpieces 4a Workpiece 4b Workpiece 5 bracket 6 Cleaning equipment 7, 7' Puller element 7a, 7a' first pull-off element 7b, 7b' second pull-off element 8, 8' guide element 8a, 8a' first guide device 8b, 8b' second guide 9a Boiler wall 9b Boiler wall 10 Retaining element 11 Collection area 12 Surface of the coating bath 13 Swivel arm 14 gripping tools 15 axle P R Retention position of the retention element 10 P o upper position of the retaining element 10 P u lower position of the retaining element 10 X direction

Claims

[1] Device for coating workpieces, comprising a vessel (1) in which a coating bath (2) is located, with at least one lifting and lowering and horizontally movable handling device (3) by means of which at least one workpiece (4, 4a, 4b) can be inserted into and removed from the coating bath (2), with at least one cleaning device (6) which has at least one squeegee (7, 7a, 7b) for removing contaminants from the surface (12) of the coating bath (2), wherein a strip-shaped retaining element (10) extending parallel to the wall of the vessel (1) is arranged in the vessel (1) adjacent to a wall (9b), which is in a retaining position (P R) at the level of the surface (12) of the coating bath (2) a trough-shaped collection area (11) formed by the retaining element (10) with the wall (9b) is defined for the contaminants and wherein the squeegee element (7, 7a, 7b) is movable parallel to the surface (12) of the coating bath (2) from a starting position in direction X onto the collection area (11) in order to bring the contaminants on the surface (12) of the coating bath (2) into the collection area (11), wherein the squeegee element (7, 7a, 7b) is liftable and lowerable and can be moved back below or above the surface (12) of the coating bath (2) in the opposite direction X. [2] Device according to claim 1, characterized by , that the retaining element (10) is removed from the retaining position (P R ) into a lower position (P u ) below the surface (12) or can be lowered to an upper position (P o) above the surface (12) to allow the removal element (7, 7a, 7b) to pass into and out of the collection area (11). [3] Equipment according to at least one of the preceding claims, characterized by , that the retaining element (10) can be raised and lowered by means of a linear motor or a swivel arm (13), that the swivel arm (13) has a gripping means (14) at one end and is attached at its other end to a stationary axle (15) and that the swivel arm (13) can preferably be actuated by means of a mechanical, electrical or pneumatic drive. [4] Establishment according to at least one of the preceding claims, characterized by that the cleaning device (6) is movable from the handling device (3). [5] Equipment according to at least one of the preceding claims, characterized by, that the handling device (3) is designed as an industrial robot having at least one arm. [6] Equipment according to at least one of the preceding claims, characterized by , that the puller element (7, 7a, 7b) is strip-shaped, U-shaped or L-shaped. [7] Establishment according to at least one of the preceding claims, characterized by , that the puller element (7, 7a, 7b) is held by at least one guide means (8, 8a, 8b), that the guide means (8, 8a, 8b) is rod-shaped and engages the puller element (7, 7a, 7b) from above or is angled and holds the puller element (7, 7a, 7b) from below. [8] Establishment according to at least one of the preceding claims, characterized by , that the cleaning device (6) has a first squeegee element (7a) and a second squeegee element (7b) which are arranged one behind the other in direction X at a distance from each other. [9] Device according to claim 8, characterized by, that between the first puller element (7a) and the second puller element (7b) there is a holder for the workpiece (4, 4a, 4b) attached to the handling device (3). [10] Method for coating workpieces, wherein at least one workpiece (4, 4a, 4b) is inserted into and removed from a vessel (1) containing a coating bath (2) by means of a lifting and lowering and horizontally movable handling device (3), wherein contaminants located on the surface (12) of the coating bath (2) are removed from the surface (12) of the coating bath (2) by means of a cleaning device (6) having at least one peeling element (7, 7a, 7b), wherein a strip-shaped retaining element (10) extending parallel to the wall of the boiler (1) is arranged adjacent to a wall (9b) in the boiler (1), which is in a retaining position (P R) at the level of the surface (12) of the coating bath (2) a trough-shaped collection area (11) formed by the retaining element (10) with the wall (9b) is defined for the contaminants, wherein the squeegeeing element (7, 7a, 7b) is moved parallel to the surface (12) of the coating bath (2) from a starting position in direction X to the collection area (11) in order to bring the contaminants into the collection area (11) and wherein the squeegee element (7, 7a, 7b) is raised or lowered to bring the contaminants above or below the retention element (10) into the collection area (11) and to retract the squeegee element (7, 7a, 7b) below or above the surface (12) of the coating bath (2) in the opposite direction X. [11] Method according to claim 10, characterized by , that the retaining element (10) is removed from the retaining position (P R ) into an upper position (P o) above the surface (12) or raised to a lower position (P u ) is lowered below the surface (12) of the coating bath (2) to allow the squeegeeing element (7, 7a, 7b) to pass into and out of the collection area (11). [12] Method according to claim 10 or 11, characterized by , that the contaminants are removed from the surface (12) of the coating bath (2) by means of a first peeling element (7a) and a second peeling element (7b), which are arranged one behind the other in direction X at a distance. [13] Method according to at least one of claims 10 to 12, characterized by , that the retaining element (10) is raised and lowered by means of a drive. [14] Method according to at least one of claims 10 to 13, characterized by , that the cleaning device (6) is moved by the handling device (3). [15] Method according to at least one of claims 10 to 14, comprising the following method steps: a) Lowering the at least one skimming element (7, 7a, 7b) to the surface (12) of the coating bath (2) and moving the skimming element (7, 7a, 7b) from the starting position in direction X onto the collection area (11) and skimming off the contaminants from a part (A) of the surface (12) of the coating bath (2); b) Lifting the retaining element (10) from the retaining position (P R ) into an upper position (P o ) above the surface (12) or into a lower position (P u ) below the surface (12) of the coating bath (2) to allow the squeegeeing element (7, 7a, 7b) to pass into and out of the collection area (11); c) Lowering the squeegee (7, 7a, 7b) below the surface (12) of the coating bath (2) and retracting the squeegee (7, 7a, 7b) in the opposite direction X until below the contaminant-free part (A) of the surface (12) of the coating bath (2); d) Lifting the squeegee (7, 7a, 7b) to the surface (12) and moving the squeegee (7, 7a, 7b) in direction X and squeegeeing the contaminants from a further part of the surface (12); e) Lowering the peeling element (7, 7a, 7b) below the surface (12) of the coating bath (2) and retracting the peeling element (7, 7a, 7b) in the opposite direction X to the starting position; f) Moving the retaining element (10) into the retaining position (P R ), to retain the contaminants in the collection area (11); g) Removal of the contaminants located in the collection area (11) from the surface (12) of the coating bath (2). [16] Method according to at least one of claims 10 to 15, characterized by , that the coating bath (2) is a zinc bath for zinc plating metallic workpieces.

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