JPS60251943A - Magnetic classifier with magnetic detector - Google Patents

Abstract

PURPOSE:To uniformize the magnetization of each part by reducing the residual magnetism of a belt, in a magnetic classifier with a magnetic detector, by arranging a demagnetizing magnet in the vicinity of the belt part corresponding to the forward position of the magnetic detector. CONSTITUTION:A demagnetizing magnet 5 is provided at a place corresponding to the forward position from a magnetic detector 3 in the belt running direction of a belt conveyor 1 so as to be close to the back surface of the belt in the lower run side thereof and the belt is passed through the magnetic field when the belt passes the place of the demagnetizing magnet 5. At this time, the magnetic field received by the belt part becomes strong once but magnetism is attenuated and reduced as the belt goes away from the magnet and residual magnetism is uniformized. By this method, mixed iron pieces are removed by a magentic classifier 4 without generating the erroneous operation of the magnetic detector 3.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention involves suspending a magnetic separator above the transport surface of a belt conveyor, and installing a magnetic detector at a location upstream of the flow of transported objects from the magnetic separator. A magnetic separator is excited based on the detection signal from this magnetic detector, and due to the electromagnetic attraction force of this magnetic separator, the magnetic pole part of the magnetic separator excites the magnetic separator. This invention relates to a magnetic sorting device equipped with a magnetic detector that attracts and removes iron pieces and the like.

[Prior art]

First, a conventional magnetic sorting device of this type will be explained with reference to FIG. In the figure, 1 is a belt conveyor, 2 is a hopper that supplies transported objects onto the belt conveyor 1, and 3 is a magnetic detector surrounding the transport side of the belt conveyor 1, which detects changes in the magnetic field due to the passage of magnetic objects such as iron pieces. A method is used in which a detection signal is generated by the change in coil current caused by the change in coil current. Reference numeral 4 denotes a magnetic separator suspended above the conveyance surface of the belt conveyor 1, and is energized based on a detection signal from the magnetic detector 3.

The conventional magnetic sorting device is configured as described above, and if the transported object is supplied from the Hocher 2 onto the belt conveyor 1, and magnetic foreign objects such as iron pieces are mixed into the transported object during the process of being transported by the conveyor. , the magnetic foreign matter is detected by the magnetic detector 3, and a detection signal is generated. Then, the magnetic separator 4 is excited based on this detection signal, and the mixed foreign matter that has been transported to the bottom of this separator together with the transported object receives an electromagnetic attraction force, is attracted to the magnetic separator, and is contained in the transported object. removed from

[Problem that the invention seeks to solve]

In this way, mixed iron pieces are removed, but the belt of the belt conveyor in such a magnetic sorting device is generally made of a non-magnetic material mainly made of rubber, so the belt itself is not affected by magnetism. I will not accept it. However, when it comes to large-sized conveyors for removing magnetic contaminants mixed in iron ore, belt conveyors using so-called steel cord belts containing wire lobe-shaped steel wires are used.

In the case of a steel-filled belt like this, the belt is magnetized by the magnetism received by the magnetic separator 4, and as a result, residual magnetism remains partially, which may cause the magnetic detector 3 to malfunction. happens. In other words, when the magnetic separator 4 is repeatedly excited on a running belt, the change in magnetic flux density causes local differences in the amount of magnetization of the belt.

For example, for a 1600 mm wide belt with 100 4 mm diameter steel wires inserted vertically, the diameter is 1 soo.
Mi! When the magnetic separator J was suspended on a belt and the excitation and interruption of the magnetic separator was repeated, it was confirmed that residual magnetism of 25 to 40 Gauss remained partially on the surface of the belt.

The signal level of the magnetic detector 3 due to this magnetism is determined by the level of the signal of the iron piece to be removed.
It is comparable to the size of 0.0 s millimeters, and it becomes impossible to determine that it is a mixed iron piece, and the magnetic detector loses its function.

[Means for solving problems]

The present invention aims to provide a magnetic sorting device capable of solving the above-mentioned conventional problems, and a demagnetizing magnet is disposed near the belt portion that is in front of the magnetic detector with respect to the belt running direction. It is characterized by:

[Effect]

The magnetic sorting device of the present invention uses a magnet to reduce the residual magnetism of the magnetized belt and to make the magnetization of each part uniform.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 3 (, -. In the following explanation, the same reference numerals will be used for parts common to FIG. 4. Fig. 1 shows a magnetic sorting device according to an embodiment of the present invention, and in the figure, 5 is a position in front of the magnetic detector 3 in the belt running direction of the belt conveyor 1. A conveyor frame (not shown) is installed at both ends of the belt so that the magnetic transport surface is separated from the belt surface by a distance of approximately 20 to 50 mm using demagnetizing magnets installed close to the back surface of the belt. can be mounted horizontally on the

As shown in the front view of FIG. 2 and the side view of FIG. 3, the demagnetizing magnet 5 has steel plate supports 6 lined up in the width direction across the belt width of the belt conveyor 1.
It has a plurality of permanent magnets 5 attached to it. In addition, the demagnetizing magnet 5 is a case in which a plurality of permanent magnets are arranged in parallel with the same poles facing up and down in the example, but N, S
The polarities may be alternately arranged in parallel, and the number of magnets need not be plural but may be one (or even an electromagnet may be used).

The present invention is provided with such a demagnetizing magnet 5, and when the belt conveyor 1 is in operation, the belt is not connected to the demagnetizing magnet 5.
When passing through the point, the belt passes through the magnetic field emitted from the magnet, which is shown by the broken line in Figure 3, and even though the magnetic field that the belt receives during this passing process becomes strong once, the magnetic field from the center of the magnet As it moves away from the object, it becomes weaker (so the magnetism of the magnetized part of the belt is attenuated and reduced, and at the same time, the local difference in the amount of magnetization disappears, and the level becomes uniform with low residual magnetism.

For example, when the residual magnetic flux density of a partially magnetized belt was 25 to 40 Gauss, as a result of implementing the present invention, the residual magnetic flux density on the belt surface was reduced to 2 to 5 Gauss,
It was also confirmed that the magnetic flux density was made uniform over the entire surface.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, even if the belt of the belt conveyor is magnetized by the magnetic flux emitted from the magnetic separator, the magnetization of the magnetized portion of the belt is reduced by passing through the demagnetizing magnet portion. The magnetic separator is able to operate reliably by sensing only the iron pieces that are mixed in the transported object and should be removed, without making the degree of magnetization uniform. .

[Brief explanation of drawings]

Figures 1 to 3 show embodiments of the present invention. Figure 1 is an overall schematic diagram, Figures 2 and 3 are front and side views of the demagnetizing magnet, and Figure 4 is a conventional FIG. 2 is a schematic perspective view showing the device of FIG. 3...Magnetic detector...Magnetic sorter 5...Magnet for demagnetization. Figure 1 Figure 3 Figure 2 Figure 4 Mouth

Claims (1)

[Claims] In a magnetic sorting device that excites a magnetic sorter above a bell F based on a detection signal from a magnetic detector, a belt is located near a portion of the belt that is in front of the magnetic detector in the running direction of the belt. A magnetic sorting device equipped with a magnetic detector, characterized in that a demagnetizing magnet is provided to reduce and make magnetization uniform.