Device and method for separating elongate magnetizable objects by length

Abstract

The invention relates to a device for separating elongate magnetizable objects from a material stream by length. The device includes a magnetic field, which magnetic field is homogeneous in a field zone; a transport device with a transport surface for carrying the material stream through the field zone in a transport direction, wherein the field direction in the field zone is oriented at right angles to the transport direction; and a separating device for carrying the elongate magnetizable objects separated by length out of the field zone in a separation direction, which separating device includes at least one take-up element which travels a path running at least partially through the field zone. In the path in the field zone the minimum distance between the at least one take-up element and the transport surface is a first distance which is smaller than or equal to the greatest main dimension of a cross-section of the field zone parallel to the transport surface. The invention also relates to a method for separating elongate magnetizable objects from a material stream by length.

Claims

1. A device for separating elongate magnetizable objects from a material stream by length, which device comprises: a magnetic field, which magnetic field is homogeneous in a field zone; a transport device with a transport surface for carrying the material stream through the field zone in a transport direction, wherein the field direction in the field zone is oriented at right angles to the transport direction; and a separating device for carrying the elongate magnetizable objects separated by length out of the field zone in a separation direction, which separating device comprises at least one take-up element which travels a path running at least partially through the field zone, wherein in the path in the field zone the minimum distance between the at least one take-up element and the transport surface is a first distance which is smaller than or equal to a greatest main dimension of a cross-section of the field zone parallel to the transport surface.

2. The device according to claim 1, wherein the first distance is smaller than or equal to the smallest main dimension of a cross-section of the field zone parallel to the transport surface.

3. The device according to claim 1, wherein the separation direction diverges from the transport direction.

4. The device according to claim 1, wherein the at least one take-up element is magnetic or magnetizable.

5. The device according to claim 1, wherein the at least one take-up element is elongate.

6. The device according to claim 1, wherein the field direction, transport direction and separation direction lie in one plane.

7. The device according to claim 1, wherein the magnetic field in the field zone is generated by a magnet arranged under the transport surface.

8. The device according to claim 7, wherein the magnetic field in the field zone is generated exclusively by the magnet arranged under the transport surface.

9. The device according to claim 1, wherein the speed of the transport surface corresponds in the field zone with the component of velocity in the transport direction of the at least one take-up element.

10. The device according to claim 1, wherein the separating device also comprises an ejector magnetic field for releasing the elongate magnetizable objects separated by length from the at least one take-up element, wherein the field direction of the ejector magnetic field has a different orientation relative to the field direction of the magnetic field in the field zone.

11. The device according to claim 10, wherein the field direction of the ejector magnetic is opposite to the field direction of the magnetic field in the field zone.

12. A method for separating elongate magnetizable objects from a material stream by length, comprising the steps of: applying a magnetic field, which magnetic field is homogeneous in a field zone; carrying the material stream through the field zone in a transport direction, wherein the field direction in the field zone is oriented at right angles to the transport direction; arranging at least one take-up element in the field zone at a first distance to the material stream, which first distance is smaller than the smallest main dimension of a cross-section of the field zone parallel to the transport direction and the material stream; and carrying the elongate magnetizable objects separated by length out of the field zone in a separation direction.

13. The method according to claim 12 with a device comprising: a magnetic field, which magnetic field is homogeneous in a field zone; a transport device with a transport surface for carrying the material stream through the field zone in a transport direction, wherein the field direction in the field zone is oriented at right angles to the transport direction; and a separating device for carrying the elongate magnetizable objects separated by length out of the field zone in a separation direction, which separating device comprises at least one take-up element which travels a path running at least partially through the field zone, wherein in the path in the field zone the minimum distance between the at least one take-up element and the transport surface is a first distance which is smaller than or equal to a greatest main dimension of a cross-section of the field zone parallel to the transport surface.

14. The method according to claim 12, wherein the at least one take-up element is magnetic or magnetizable, wherein the elongate magnetizable objects separated by length are taken up magnetically.

15. The method according to claim 12, also comprising the step of releasing the elongate magnetizable objects separated by length from the at least one take-up element by means of an ejector magnetic field, wherein the field direction of the ejector magnetic field has a different orientation relative to the field direction of the magnetic field in the field zone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features of the invention are further elucidated with reference to the accompanying drawings.

(2) The terms Fig., Figs., Figure, and Figures are used interchangeably in the specification to refer to the corresponding figures in the drawings.

(3) FIG. 1 shows a schematic representation of a device according to the invention.

(4) FIG. 2 shows a detail of the representation of FIG. 1.

(5) FIG. 3 shows a schematic representation of a homogeneous field zone close to the pole of a magnet.

DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows a schematic representation of a device 1 according to the invention. A material stream 3 of elongate magnetizable objects 4 is arranged on transport surface 2 of the transport device. The objects 4 are carried in transport direction 5 into the field zone 6, where a homogeneous magnetic field has been applied. The magnetic field is generated by a magnet pole 7 of a magnet 8 arranged under transport surface 2. In field zone 6 the field direction of the homogeneous magnetic field is oriented at right angles to transport surface 2. The separating device 9 carries elongate magnetic object 10 separated by length out of the field zone 6. The objects 10 separated by length are taken up in the field zone of transport surface 2 by means of elongate take-up elements 11 and discharged in the separation direction 12. An ejector magnet 13 generates an opposite field for releasing the objects 10 from the take-up elements 11 into receptacle 14. The remaining, shorter object 4 are cleared from transport surface 2 at the end of the transport device and collected in a second receptacle 15. The smallest main dimension 16 of a cross-section of field zone 6 parallel to transport surface 2 is greater than the length of the objects 10 to be separated.

(7) FIG. 2 shows a detail of the representation of FIG. 1. The smallest main dimension 16 of a cross-section of field zone 6 parallel to transport surface 2 is greater than the length of the objects 10 to be separated. In the path of the take-up elements 11, which runs partially through field zone 6, the first distance 17 is the minimum distance between take-up elements 11 and transport surface 2. This first distance 17 is smaller than the smallest main dimension 16 of a cross-section of field zone 6 parallel to transport surface 2. This first distance 17 is also smaller than or equal to a greatest main dimension 18 of a cross-section of the field zone 6 parallel to the transport surface 2.

(8) FIG. 3 shows a schematic representation of a homogeneous field zone 20 close to the pole 21 of a magnet 22. Although the field lines 23 close to the edges of magnet 22 bend sharply, the field lines 24 which are further removed from the edges and cross the field zone 20 are roughly parallel, resulting in a homogenous field in field zone 20, as required for application of the invention.