Apparatus for treating a metal strip including an electromagnetic stabilizer utilizing pot magnets

Abstract

An apparatus for treating a metal strip after it has exited from a coating container with a liquid coating material, for example zinc is provided. The apparatus includes a blow-off device arranged above the coating container having an air outlet gap for blowing off excess parts of the still liquid coating material from the surface of the metal strip after the passing of the metal strip through the coating container. An electromagnetic stabilizer is arranged above the blow-off device and has a plurality of individual magnets for stabilizing the metal strip after leaving the coating container and the blow-off device. In order to further increase the efficiency of the apparatus, at least some of the magnets of the stabilizer are formed as pot magnets with pot coils.

Claims

1. An apparatus for treating a metal strip after the metal strip has exited from a coating container of a liquid coating material, comprising: a blow-off device arranged above the coating container, the blow-off device having an air outlet gap for blowing off an excess liquid coating material from a surface of the metal strip after the metal strip has passed through the coating container; and an electromagnetic stabilizer arranged above the blow-off device comprising a first plurality of magnets and a second plurality of magnets for stabilizing the metal strip after leaving the coating container and the blow-off device, wherein the first plurality of magnets and the second plurality of magnets are arranged on opposite sides of the metal strip, wherein the first plurality of magnets and the second plurality of magnets are individually fastened to a traverse by a plurality of stabilizer displacement devices, and each magnet of the first plurality of magnets and each magnet of the second plurality of magnets being individually fastened to the traverse by a corresponding one of the plurality of stabilizer displacement devices, wherein the plurality of stabilizer displacement devices enables individual, translational displacement of each magnet of the first plurality of magnets and the second plurality of magnets in a horizontal plane relative to the traverse, and wherein each magnet of the first plurality of magnets is configured to be displaced relative to each magnet of the second plurality of magnets; wherein the first plurality of magnets includes a first pot magnet with a first pot coil therein, wherein the second plurality of magnets includes a second pot magnet with a second pot coil therein, wherein the first pot magnet includes a first distance sensor arranged in a middle of the first pot coil, and wherein the second pot magnet includes a second distance sensor arranged in a middle of the second pot coil.

2. The apparatus according to claim 1, wherein all of the magnets of the electromagnetic stabilizer are pot magnets with pot coils therein.

3. The apparatus according to claim 1, further comprising a horizontal traverse mounted between two vertical side uprights, wherein the blow-off device is suspended from the horizontal traverse, and wherein the electromagnetic stabilizer is arranged between the horizontal traverse and the blow-off device and fastened to and suspended from the horizontal traverse independently of the blow-off device.

4. The apparatus according to claim 1, wherein the electromagnetic stabilizer is arranged above the blow-off device in such a manner that a distance between a line of action of a maximum force of the electromagnetic stabilizer on the metal strip and the air outlet gap is in a range of 100-800 mm.

5. The apparatus according to claim 1, further comprising a regulating device for controlling a position of the metal strip in a slot of the electromagnetic stabilizer to a predetermined target center position in accordance with distances determined by the first distance sensor and the second distance sensor through a variation of a first current through the first pot coil and a variation of a second current through the second pot coil.

6. The apparatus according to claim 1, wherein each stabilizer displacement device is formed to displace a corresponding magnet to which the corresponding one of the plurality of stabilizer displacement devices is individually fastened in a width direction of the metal strip.

7. The apparatus according to claim 1, wherein the blow-off device has the air outlet gap on both sides of the metal strip.

8. The apparatus according to claim 1, wherein the first plurality of magnets includes four magnets that are arranged at a same distance underneath the traverse.

9. The apparatus according to claim 1, wherein each of the first plurality of magnets are configured to move parallel to a plane of the metal strip and assume a position which is offset relative to the second plurality of magnets.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plan view of an apparatus for treating a metal strip.

(2) FIG. 2 shows a cross-section of the apparatus as in FIG. 1.

(3) FIG. 3 and FIG. 4 are top views of a slot of a blow-off device and an electromagnetic stabilizer, in each case with a marking of the target center position and various undesirable actual positions of the metal strip.

DETAILED DESCRIPTION

(4) The invention is described in detail below in the form of exemplary embodiments with reference to the figures mentioned. In all figures, the same technical elements are designated with the same reference signs.

(5) FIG. 1 shows an apparatus 100 for treating a metal strip. It comprises two vertically extending uprights 150 arranged at the sides, on which a traverse 130, also called a nozzle carrier, is mounted so that it can be displaced vertically; see the double arrows in FIG. 1. The apparatus 100 can also be swiveled in the horizontal plane. For this purpose, one of the two uprights 150 is formed as fixed side A, on which the traverse is mounted so that it can swivel around a vertical axis of rotation. The opposite upright, on the other hand, is formed as loose side B and only supports the traverse vertically. Due to this design of the uprights as fixed and loose sides, the apparatus 100 and in particular the traverse 130 can be aligned symmetrically to the metal strip 200 by swiveling it horizontally with the aid of an upright displacement device 158 when the metal strip 200 is at an angle. As a result, the wide sides of the traverse are always to be aligned parallel to the metal strip and both are to have the same distance from it.

(6) A blow-off device 110 or nozzle is suspended from the traverse 130. The coupling of the blow-off device 110 to the traverse 130 does not take place rigidly, but via a blow-off displacement device 115, which is formed to displace the blow-off device 110 relative to the traverse 130 in the horizontal plane; that is, in particular perpendicular to the center plane 160 of the apparatus. In addition, the blow-off displacement device 115 is formed to swivel the blow-off device 110 around its own longitudinal axis L and thus suitably set against the metal strip 200.

(7) Between the traverse 130 and the blow-off device 110, a stabilizer 140, also called Dynamic Electro-Magnetic Coating Optimizer (DEMCO), is attached to the traverse. The stabilizer 140 comprises a plurality of individual magnets 144 on each side of the metal strip. Preferably, all such magnets are formed as pot magnets. Preferably, each of such magnets is fastened individually to the traverse by a stabilizer displacement device 145. Such stabilizer displacement devices 145 enable the individual, translational displacement of each individual magnet in the horizontal plane relative to the traverse; that is, perpendicular and parallel to the center plane 160 of the apparatus 100, in particular in the longitudinal direction of the traverse. In addition, the stabilizer displacement device 145 can also be formed to swivel the stabilizer 140 in the horizontal plane relative to the traverse 130 and relative to the blow-off device 110 around a vertical axis of rotation.

(8) The use of the pot magnets is not limited to the arrangement between the traverse and the blow-off device. Rather, the pot magnets can also be arranged above the traverse.

(9) FIG. 2 shows the apparatus from FIG. 1 in a cross-sectional view. The reference sign 170 designates a control device for controlling the stabilizer displacement devices 145. A coating container 300 can be recognized; in principle, this is located below the apparatus 100. The metal strip 200 to be coated is fed in transport direction R into the coating container 300 with the liquid coating material 310 and deflected into the vertical position by a deflection roller 320. It then passes from bottom to top initially through the blow-off device 110 and then through the stabilizer 140. In an advantageous configuration, the distance d between the line of action of the maximum force F of the stabilizer on the metal strip 200 and the air outlet gap 112 lies in a range from 100 to 800 mm, preferably in a range from 100 to 550 mm or further preferably in a range from 100 to 450 mm.

(10) The blow-off device 110 spans a slot 122, through which the metal strip 200 is guided. The blow-off device is used to blow off excess coating material from the surface of the metal strip 200.

(11) To ensure that the blow-off on the top and bottom sides of the metal strip 200 is uniform, it is important that the metal strip 200 passes through the slot 122 of the blow-off device 110 in a specified target center position, also known as the center plane 160 or the fitting line reference position, as symbolized in FIG. 3 in the form of the continuous line in the X direction. This target center position is characterized in particular by uniform distances or distance distributions to the inner edges of slot 122 of the blow-off device 110. In addition to the desired target center position 128, FIG. 3 also shows possible undesired actual positions of the metal strip as dashed lines. For example, undesired actual layers for the metal strip 200 consist of the fact that it is twisted in relation to the target center layer or shifted parallel in the Y direction.

(12) FIG. 4 shows a third possible undesired actual position, in which the metal strip 200 is shifted parallel to the target center position in the X-direction; that is, in the width direction.

(13) On its part, the electromagnetic stabilizer 140 has a slot 142 through which the metal strip 200 is also guided. Here as well, the metal strip 200 passes through the slot 142, preferably in a predetermined target center position 160, as shown in FIGS. 3 and 4. This is achieved by ensuring that the forces provided by the magnets of the 140 electromagnetic stabilizer act in a suitable manner on the metal strip 200. The same applies to slot 142 and the target center position pursued there, as before with reference to FIGS. 3 and 4 for the slot 122 of the blow-off device 110.

(14) A first detection device 154 for detecting a deviation of the actual position of the metal strip 200 from a predetermined target center position in the slot 122 of the blow-off device 110 is further arranged between the stabilizer 140 and the blow-off device 110. Alternatively, the first detection device 154 can be formed to detect only the actual position of the metal strip. A regulating device 180 is also provided to regulate the actual position of the metal strip 200 to the specified target center position 128 in the slot 122 of the blow-off device, as explained above with reference to FIGS. 3 and 4. This regulation can be effected a) by displacing the blow-off device 110 with the aid of a blow-off displacement device 115 and/or b) by displacing the traverse 130, on which the blow-off device 110 is suspended, with the aid of an upright displacement device 158. The regulation takes place in response to the detected deviation from the actual position to the target position. If the deviation of the actual position from the target center position is not determined in the first detection device 154, it can also be determined, for example, within the regulating device 180. The blow-off device 110 is displaced in a horizontal plane transverse to the transport direction R of the metal strip in accordance with the detected deviation of the actual position of the metal strip from the specified target center position in the slot 122 of the blow-off device. In other words: If it is determined that the metal strip 200 does not pass through the slot 122 in the target center position 128, the blow-off device 110 is displaced by the blow-off displacement device 115 in such a manner that the metal strip passes through the slot 122 of the blow-off device once again into the target center position 128. For this purpose, the first detection device 154 is formed in such a manner that it can preferably detect all three actual positions of the metal strip 200 deviating from the target center position 128 as described above with reference to FIGS. 3 and 4.

(15) The specified displacement of the blow-off device 110 is not to affect the electromagnetic stabilizer 140. For this purpose, the control device 170 is formed to control the stabilization displacement device 145 of the individual magnets 144 in such a manner that, in the event of a displacement of the blow-off device 110 with respect to a fitting line reference position, the electromagnetic stabilizer 140 is not moved with it, but can remain at its original position. The stabilizer 140 and the blow-off device 110 are decoupled from each other. That is, they can be moved independently from each other and relative to each other by their respective displacement devices 145, 115. The fitting line reference position 160 designates a fixed defined center plane of the apparatus. In contrast, the target center positions 128 refer to slots 122, 142. The control device 170 therefore acts on the stabilizing displacement devices 145 in such a manner that, in the event of the displacement of the blow-off device 110, the electrical stabilizers 140 preferably makes the exact opposite movement to that of the blow-off device 110; that is, as a result, it preferably remains in its original position.

(16) In order to realize this special type of control for the stabilizer displacement devices 145, the control device 170 is able to evaluate different situations. On the one hand, the control device 170 can be formed to carry out the displacement of the electromagnetic stabilizer 140 or the individual magnets 144 in accordance with the deviation of the actual position of the metal strip from the predetermined target center position of the metal strip in the slot 122 of the blow-off device 110 detected by the first detection device 154.

(17) Alternatively or in addition, the control device 170 can be formed to carry out the displacement of the electromagnetic stabilizer 140 or the individual magnets 144 as required and in the opposite direction to the displacement of the blow-off device 110 detected by a second detection device 155. The second detection device 155 serves to detect the displacement of the blow-off device 110 in relation to a fitting line reference position 160 of the apparatus 100.

(18) Finally, according to an additional alternative or as a supplement, the control device 170 can be formed to cause the displacement of the electromagnetic stabilizer 140 and the individual magnets 144, respectively, in accordance with a detected deviation of the actual position of the metal strip from a predetermined target center position in the slot 142 of the electromagnetic stabilizer. A prerequisite for this is that a third detection device 156 is provided for detecting the specified deviation of the actual position of the metal strip from the predetermined target center position in the slot 142 of the electromagnetic stabilizer 140. Preferably, each magnet 144 is assigned with such a third detection device 156 as a distance sensor. Preferably, such sensors are arranged in the pot magnets. For example, they work optically or with the aid of induced eddy currents.

(19) Each of the first, second and third detection devices 154, 155, 156 is formed to detect preferably all conceivable deviations of an actual position of the metal strip from the desired target center position. These include in particular a (parallel) displacement of the metal strip in the x or y direction or a twist, as explained above with reference to FIGS. 3 and 4. Accordingly, the stabilizing and blow-off displacement devices 145, 115—with suitable actuation by the regulating device 180 or the control device 170—are formed to move the blow-off device 110 and the electromagnetic stabilizer 140 in the horizontal plane transversely to the transport direction R of the metal strip in any manner, in particular to displace them (in a parallel direction) or to rotate them around a vertical axis of rotation, in order to realize the passing through of the metal strip into the target center position.

(20) The first and third detection devices 154, 156 and optionally also the second detection device 155 can be realized in the form of one or more optical sensor devices 190. In this respect, the sensor device forms a structural unit for the specified detection devices. Preferably, one sensor device 190 per coil is provided in the electromagnetic stabilizer 140. The measured values of all sensor devices are typically averaged. The sensor device 190 can also be generally referred to as a distance detection device.

(21) If a deviation of the actual position from the target position of the metal strip is detected within the electromagnetic stabilizer 140, in particular with the aid of the third detection device 156, the actual position to the target position or on the fitting line is regulated with the aid of the control 170 through suitable individual variation of the currents through the coils in the magnets 144.

LIST OF REFERENCE SIGNS

(22) 100 Apparatus

(23) 110 Blow-off device

(24) 112 Air outlet gap

(25) 115 Blow-off displacement device

(26) 122 Slot of the blow-off device

(27) 128 Target center level

(28) 130 Traverse

(29) 140 Stabilizer

(30) 142 Slot of the stabilizer

(31) 144 Magnet

(32) 145 Stabilizer displacement device

(33) 150 Side upright

(34) 154 First detection device

(35) 155 Second detection device

(36) 156 Third detection device (=distance sensor)

(37) 158 Upright displacement device

(38) 160 Fitting line reference position of the apparatus

(39) 170 Control device

(40) 180 Regulating device

(41) 190 Sensor device

(42) 200 Metal strip

(43) 300 Coating container

(44) 310 Coating material

(45) A Fixed side

(46) B Loose side

(47) d Distance

(48) F Force

(49) L Longitudinal axis blow-off device

(50) R Transport direction of the metal strip

(51) X Width direction of the metal strip in the target center position

(52) Y Direction transverse to the plane spanned by the metal strip