JPS6332506B2 - - Google Patents

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 the electromagnetic attraction force of this magnetic separator causes the magnetic pole part to remove iron pieces, etc. mixed in objects being transported on a belt conveyor. This invention relates to a magnetic sorting device equipped with a magnetic detector that adsorbs and removes.

[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 objects to be transported 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. 4
is a magnetic separator suspended above the transport surface of the belt conveyor 1, and is configured to be excited based on a detection signal from a magnetic detector 3.

The conventional magnetic sorting device is configured as described above, and the conveyance object is supplied from the hopper 2 onto the belt conveyor 1, and during the process of being conveyed by the conveyor, magnetic foreign objects such as iron pieces are mixed into the conveyance object. If there is a magnetic foreign object, the magnetic detector 3 detects the magnetic foreign object and generates a detection signal. 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, etc. 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 don't accept it. However, when it comes to large conveyors for removing magnetic contaminants mixed in iron ore, belt conveyors using so-called steel cord belts containing wire rope-like steel wires are used.

However, in the case of such a steel-containing belt, the belt is magnetized by the magnetism received from the magnetic separator 4, and 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, a change in magnetic flux density causes a partial difference 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
When an 1800 mm magnetic separator was suspended on a belt and the excitation and cutoff 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 10 mm × 10 mm × of the iron piece to be removed.
The size of the magnet is comparable to that of a 100mm piece of iron, making it impossible to determine whether it is a piece of mixed iron and causing the magnetic detector to lose 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 with reference to FIGS. 1 to 3. In the following description, the same reference numerals will be used for parts common to those in FIG. 4 to simplify the description. FIG. 1 shows a magnetic sorting device according to an embodiment of the present invention. In the figure, 5 is located at the lower part of the belt, which is a location in front of the magnetic detector 3 in the belt running direction of the belt conveyor 1. A demagnetizing magnet is installed close to the back of the belt, and the magnetic pole surface is installed horizontally on the conveyor frame (not shown) at both ends with a distance of approximately 20 to 50 mm from the belt surface. It will be done.

The configuration of the demagnetizing magnet 5 is shown in the front view of FIG.
As shown in the side view of FIG. 3, the belt conveyor 1 has a plurality of permanent magnets 5 attached to a steel plate support 6 and arranged in a row in the width direction of the belt conveyor 1. In addition, the demagnetizing magnet 5 is a case in which a plurality of permanent magnets are arranged in parallel with the same polarity facing up and down in the embodiment, but N and S polarity may be arranged in parallel alternately. It is not necessary that the number of magnets be two, but one may be sufficient, and furthermore, it may be an electromagnet.

The present invention is provided with such a demagnetizing magnet 5, and when the belt passes through the demagnetizing magnet 5 during operation of the belt conveyor 1, the magnetic field emitted from the magnet as shown by the broken line in FIG. The magnetic field that the belt receives during this passage becomes strong once, but it weakens as it moves away from the center of the magnet, so the magnetism of the magnetized part of the belt is attenuated and reduced. At the same time, local differences in the amount of magnetization disappear, and the level becomes uniform with low residual magnetism.

As an 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, and the residual magnetic flux density was reduced to 2 to 5 Gauss over the entire surface. It was confirmed that the magnetic flux density was made uniform.

〔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 part of the belt is reduced by passing through the demagnetizing magnet part. Since the degree of magnetization is reduced and the degree of magnetization is homogenized, the magnetic detector is no longer sensitive to the passage of the belt itself, so that the magnetic detector does not operate erroneously and removes any particles mixed in the transported object. This means that only the iron pieces, etc. that should be detected are detected, and the operation of the magnetic separator can be ensured.

[Brief explanation of the drawing]

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, 4...Magnetic sorter, 5...
Magnet for demagnetization.

Claims (1)

[Claims] 1. In a magnetic sorting device that excites a magnetic separator above the belt based on a detection signal from a magnetic detector, a magnetic separator located above the belt in the vicinity of a portion of the belt that is in front of the magnetic detector with respect to 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.