NON-CONTACT STRIP GUIDING

Abstract

A process and apparatus for controlling the strip run (4) of a metal strip (10) through a floating furnace (3). The strip run (4) is controlled contact-free with the aid of an electromagnetic device (1) that generates a Lorentz force acting transversely to the strip run.

Claims

1. A method for controlling transverse horizontal deviation of a metal strip passing horizontally in a running direction on air cushions through a floating furnace, comprising: sensing the transverse position of the strip at a location along the running direction; and in response to a sensed deviation in the transverse position of the strip, controlling the transverse position of the running strip with contact-free forces applied by a controlled electromagnetic field.

2. The method according to claim 1, wherein a fixed AC electromagnet device generates said controlled electromagnetic field.

3. The method according to claim 2, wherein: the metal strip is a nonferrous metal strip; the electromagnet device induces eddy currents in the strip, which in turn create another magnetic field that interacts with the magnetic field of the electromagnet device to produce a Lorentz force on the level of the strip in a direction transverse to the strip running direction.

4. The method according to claim 1, wherein the electromagnetic device comprises hollow conductor windings and a cooling medium is passed through the electromagnetic device.

5. The method according claim 1, further comprising: guiding the metal strip through a cooling line on an air cushion immediately after the floating furnace; sensing the transverse position of the strip at a location along the running direction of the cooling line; and in response to sensed deviations in the transverse position of the strip in the cooling line, controlling the transverse position of the running strip with contact-free forces applied by another controlled electromagnetic field.

6. The method according to claim 2, wherein when the position of the sensed metal strip deviates, a control signal activates the electromagnetic device to generate said electromagnetic field.

7. A method for controlling transverse horizontal deviation of a metal strip passing horizontally in a running direction on air cushions through a treatment station, comprising: subjecting the running strip to Lorentz forces acting transversely to the running direction.

8. The method according to claim 7, wherein the treatment station is an annealing furnace.

9. The method according to claim 7, wherein the treatment station is a cooling station following a furnace.

10. The method according to claim 7, wherein: the metal strip is a nonferrous metal strip; the Lorentz forces are produced by a primary magnetic field generated by an AC electromagnet device; and the primary magnetic field induces eddy currents in the strip, which in turn create secondary magnetic fields that interacts with the primary magnetic field to produce a Lorentz force on the level of the strip in a direction transverse to the running strip.

11. The method according to claim 10, wherein said electromagnet device is in a fixed position and generates a variable primary magnetic field which produces variable Lorenz forces.

12. The method according to claim 11, including controlling the variable magnetic field to adjust the direction and amplitude of the electromagnetic force acting on the strip.

13. The method according to 8, wherein the electromagnetic device includes coils and a cooling medium is passed through the coils.

14. A device for controlling a metal strip running within a floating furnace, comprising: a running strip position sensor; and adjustable AC electromagnets responsive to the position sensor, arranged inside the floating furnace in spaced vertical alignment with the metal strip, for generating a Lorentz force acting on the metal strip transversely to the running strip on the level of the strip run.

15. The device according to claim 14, wherein the electromagnets have coils in the form of hollow conductors through which a cooling medium passes.

16. The device according to claim 15, wherein the cooling medium is selected from the group consisting of water, demineralized water, and a bio-based dielectric fluid.

17. The device according to claim 14, wherein the electromagnets are shielded by a ceramic cover.

18. The device according to claim 14, including a metal strip passing along a running direction on a cushion of air through an annealing furnace; and wherein the position sensor is located within the furnace upstream of the electromagnets; and at least one electromagnet is situated in fixed position above the running strip and at least one electromagnet is situated in fixed position below the running strip.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0019] An embodiment of the invention is described below with reference to the accompanying FIG. 1.

DETAILED DESCRIPTION

[0020] FIG. 1 shows a metal strip 10in the present case an aluminum stripuncoiled from a decoiler 9. The S-rolls 8 guide the aluminum strip 10 and maintain the strip tension before the strip is fed to the floating furnace 3. In the floating furnace 3, the aluminum strip 10 is transported contact-free with the aid of air cushions generated by injectors arranged above and below the strip and then annealed at temperatures of over 500 C.

[0021] The lateral drift of the aluminum strip 10 is measured with the aid of the position sensor 2, which may take any known form. The electromagnetic adjustment device is formed by electromagnets 1 located above and below the aluminum strip 10, but not touching it. In the event of lateral drift detected by sensor 2, the electromagnets 1 are activated and the lateral drift thus corrected perpendicular to the strip run 4. The electromagnets 1 can be controlled with the aid of a potentiometer, for example, which changes the direction and amplitude of the electromagnetic force.

[0022] Subsequently, the aluminium strip is guided through a cooling section 5 floating on an air cushion. The electromagnets 1 needed for strip guiding can also be arranged in the cooling section 5 or in the transition area between the annealing furnace 3 and the cooling line 5. The cooled and thus less sensitive aluminum strip 10 is then guided over a guide roll 6 and fed to a coiler 7.

[0023] The embodiment illustrated in the drawing merely constitutes a preferred version of the invention. The invention also covers other embodiments in which gentle strip guiding is needed.