JP2020175373A - Magnetic separator - Google Patents

Abstract

To provide a magnetic separator which can be downsized, has a small magnetic field leakage to the exterior and can adjust a magnetic field strength.SOLUTION: A magnetic separator has: a magnetic separation column 10 which is constituted of a cylindrical body and a filter comprising a magnetic material located in the cylindrical body; and a double ring-shaped Halbach magnetic circuit which applies a magnetic field to the magnetic separation column 10. The double ring-shaped Halbach magnetic circuit is constituted of an inner peripheral side Halbach magnetic circuit and an outer peripheral side Halbach magnetic circuit which surrounds the inner peripheral side Halbach magnetic circuit. The inner peripheral side Halbach magnetic circuit and the outer peripheral side Halbach magnetic circuit are relatively rotatable.SELECTED DRAWING: Figure 5

Description

The present invention relates to a magnetic separation device that can be miniaturized, can change the magnetic field strength, and has a small magnetic field leakage to the outside. ..

There is a magnetic separation device as a means for removing metal impurities made of a magnetic substance in a liquid. For example, a magnetic separation device including a pipe for flowing a liquid containing magnetic particles, a filler made of a magnetic material arranged inside the pipe, and a magnetic circuit for applying a magnetic field to the filler from the outside of the pipe is known.
Patent Document 1 discloses a magnetic separation device in which a column containing a filler in which a magnetic net is laminated is arranged in the middle of a pipe, and a magnetic field is applied to the column from the outside of the pipe. In Patent Document 1, magnets having different magnetic poles are arranged on each facing surface side of the U-shaped yoke, and a column is placed in the facing surface to apply a magnetic field to a filler made of a magnetic material in the column. Discloses a technique for adsorbing and removing metal impurities of a magnetic material on a filler.

Japanese Unexamined Patent Publication No. 2012-187538

FIG. 9 shows a means (magnetic circuit) for applying a magnetic field composed of a yoke and a magnet in the magnetic separation device described in Patent Document 1. 40 is a magnet and 30 is a U-shaped yoke. In the case of such a structure, the magnetic field may leak from the opening surfaces (upper and lower surfaces and front surface of the yoke) of the yoke shown in FIG. 9 other than the facing surfaces of the magnets, which may affect other devices in the vicinity of the magnetic separation device. is there.
Further, in a structure in which magnets are opposed to each other and a column containing a filler is arranged therein, it is necessary to change the distance between the opposing magnets when trying to change the magnetic field strength. If the magnetic circuit is provided with a mechanism for adjusting the magnetic field strength by widening the distance between the magnets, the magnetic separation device may become large.

Further, a general magnetic separation device has a magnetic filter that adsorbs metal impurities inside. Metal impurities adsorbed on the magnetic filter are removed by backwashing after a certain period of time and reused. At this time, it is necessary to once set the magnetic field strength applied to the magnetic filter to 0 (hereinafter, the magnetic field may be referred to as "0" or "0 magnetic field"). In the magnetic separation device described in Patent Document 1, it is necessary to separate the U-shaped yoke from the column at one end, which complicates the operation.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a magnetic separation device which can be miniaturized, has a small magnetic field leakage to the outside, and can adjust the magnetic field strength. To do.

The magnetic separation device according to the present invention includes a magnetic separation column composed of a cylinder having a hollow portion and a filter made of a magnetic material arranged in the cylinder, and a double ring for applying a magnetic field to the magnetic separation column. The double ring-shaped Halbach magnetic circuit is composed of an inner peripheral side Halbach magnetic circuit and an outer peripheral side Halbach magnetic circuit surrounding the inner peripheral side Halbach magnetic circuit, and the inner peripheral side Halbach magnetic circuit. The magnetic circuit and the Halbach magnetic circuit on the outer peripheral side are magnetic separation devices characterized in that they are relatively rotatable.

According to the present invention, since the double ring-shaped Halbach magnetic circuit is used, it is possible to adjust the strength of the magnetic field applied to the filter, which is a small and magnetic material, and also to prevent the leakage magnetic field to the outside. Can be reduced.
Furthermore, it is possible to perform back cleaning without removing the magnetic circuit.

The magnetic separation device according to the present invention has a magnetic separation column composed of a cylinder having a hollow portion through which a liquid flows and a filter made of a magnetic material arranged in the cylinder, and the magnetic separation column so as to be orthogonal to the flow of the liquid. It has a double ring-shaped Halbach magnetic circuit that applies a magnetic field to the magnetic separation column, and the double ring-shaped Halbach magnetic circuit includes an inner peripheral Halbach magnetic circuit and an outer peripheral Halbach magnetic circuit that surrounds the inner Halbach magnetic circuit. The inner peripheral side Halbach magnetic circuit and the outer peripheral side Halbach magnetic circuit are magnetic separation devices characterized in that they are relatively rotatable.

According to the present invention, since the double ring-shaped Halbach magnetic circuit is used, it is possible to adjust the strength of the magnetic field applied to the filter, which is a small and magnetic material.
Furthermore, it is possible to perform back cleaning without removing the magnetic circuit.

In the magnetic separation device of the present invention, the outer peripheral side Halbach magnetic circuit and the inner peripheral side Halbach magnetic circuit are polygonal in cross-sectional view, and the upper bottom of the trapezoidal magnet in cross-sectional view is centered on the polygon. It is a magnetic separation device characterized in that it is configured by combining trapezoidal legs so as to face each other.

According to the present invention, it is possible to easily manufacture a Halbach magnetic circuit.

In the magnetic separation device of the present invention, the trapezoidal magnet in the cross-sectional view has a perpendicular magnetization magnet having a magnetization angle perpendicular to the upper and lower bases and a parallel magnetization having a magnetization angle parallel to the upper base and the lower base. It is a magnetic separator characterized by two types of magnets.

According to the present invention, the Halbach magnetic circuit can be configured with magnets having a small number of magnetization angles, leading to cost reduction.

The magnetic separation device of the present invention is a magnetic separation device characterized in that the vertically magnetizing magnets are arranged to face each other, and the vertically magnetizing magnets of the outer peripheral side Halbach magnetic circuit can change the facing distance.

According to the present invention, the strength of the magnetic field applied to the filter which is a magnetic material can be adjusted, and the strength of the magnetic field can be easily set to 0 magnetic field.

According to the present invention, the magnetic separation device can be miniaturized, the magnetic field strength applied to the filter can be adjusted, and the magnetic field leakage to the outside can be reduced. Furthermore, it is possible to perform back cleaning without removing the magnetic circuit.

It is a plan view (A) and CC sectional view (B) of the magnetic circuit (double Halbach magnetic circuit) of the magnetic separation apparatus which is an embodiment of this invention. It is a top view of the inner peripheral side Halbach magnetic circuit (F) and the outer peripheral side Halbach magnetic circuit (G) constituting the double ring-shaped Halbach magnetic circuit according to the embodiment of the present invention. It is a top view of the double Halbach magnetic circuit of the magnetic separation apparatus which is an embodiment of this invention. D is the case where the magnetic field of the double ring-shaped Halbach magnetic circuit is maximized. E is the case where the magnetic field of the ring-shaped Halbach magnetic circuit is 0. It is JJ sectional view (I) of the plan view (H) and the plan view (H) of the magnetic separation column of the magnetic separation apparatus which is an embodiment of this invention. 3 is a plan view (K) and an MM cross-sectional view (L) of the plan view (K) of the magnetic separation device according to the embodiment of the present invention. FIG. 5 is a cross-sectional view of a shaft in which a magnetic separation device according to an embodiment of the present invention is attached to a pipe through which a liquid for magnetic separation flows. It is a shaft sectional view which shows the state of the back-cleaning of the magnetic separation apparatus which is an embodiment of this invention. It is a QQ sectional view (P) of the plan view (O) and the plan view (O) which shows the magnetic separation apparatus which is another Embodiment of this invention. It is a perspective view which shows the magnetic circuit in the conventional magnetic separation apparatus. It is a plan view (S) and RR sectional view (T) of the plan view (S) which shows the magnetic separation apparatus which is still another Embodiment of this invention. It is a top view which showed the situation which changes the distance of a vertically magnetizing magnet in the magnetic separation apparatus which is still another Embodiment of this invention. When the distance of the perpendicularly magnetized magnet is reduced (U), when the distance of the perpendicularly magnetized magnet is talked about (V) It is sectional drawing which shows an example of the mechanism which changes the distance of a perpendicular magnetizing magnet in still another embodiment of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments thereof.

The double ring-shaped Halbach magnetic circuit 1 of the magnetic separation device 100 according to the embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. Reference numeral 1 denotes a double ring-shaped Halbach magnetic circuit of the magnetic separation device 100. 7 shown in FIG. 2 is a Halbach magnetic circuit on the inner peripheral side, and 8 is a Halbach magnetic circuit on the outer peripheral side. The inner peripheral side Halbach magnetic circuit 7 has a regular polygon in a plan view, and the legs of each trapezoid are aligned so that the upper base of the magnet 3 having a trapezoidal cross section faces the center of the polygon. The direction of magnetization of each magnet is set so that the direction of the magnetic field is aligned in one direction inside the Halbach magnetic circuit 7 on the inner peripheral side (right side in FIG. 2). Reference numeral 6 denotes an inner cover, which is tubular and non-magnetic. For example, the magnet 3 is fixed to the outer peripheral surface side of the inner cover 6 by a known method. A magnetic separation column described later is arranged inside the inner cover 6.

The outer peripheral side Halbach magnetic circuit 8 has a regular polygon in a plan view, and the legs of each trapezoid are aligned so that the upper base of the magnet 2 having a trapezoidal cross section faces the center of the polygon. The direction of magnetization of each magnet is set so that the direction of the magnetic field is aligned in one direction inside the Halbach magnetic circuit 8 on the outer peripheral side (right side in FIG. 2). Reference numeral 5 denotes an inner cover, which is tubular and non-magnetic. For example, the magnet 2 is fixed to the outer peripheral surface side of the inner cover 5 by a known method. Reference numeral 4 denotes an outer cover, which is tubular and is a non-magnetic material, and protects the outer peripheral side Halbach magnetic circuit. The outer cover 4 magnet 2 is fixed to the inner peripheral surface side of the outer cover 4 by a known method.

The characteristics, size, and magnetization direction of the magnet are adjusted so that the magnetic field strength of the inner peripheral side Halbach magnetic circuit 7 and the magnetic field strength of the outer peripheral side Halbach magnetic circuit 8 are the same.

An inner peripheral Halbach magnetic circuit 7 is arranged inside the inner cover 5. The outer peripheral side Halbach magnetic circuit 8 is rotatably held around the inner peripheral side Halbach magnetic circuit 7 (as shown by an arrow in FIG. 1) by a known method.
A non-magnetic tube may be fixedly arranged on the outside of the magnet 3 of the Halbach magnetic circuit 7 on the inner peripheral side, and may be slid with the middle cover-5 when the Halbach magnetic circuit 8 on the outer peripheral side is rotated. .. It is possible to suppress wear of the corners of the magnet 3.

Although the magnet 3 (3a) and the magnet 2 (2a) are shown integrally in the axial direction (in FIG. 1B), a plurality of magnets may be combined in the axial direction. Further, the trapezoidal magnets 2 and 3 in a plan view may be configured to be trapezoidal with a plurality of magnets.

The details of the magnet 2 and the magnet 3 will be described. The magnet 2 and the magnet 3 are roughly classified into four types according to the angle of magnetization with respect to the upper and lower bottom surfaces having a trapezoidal cross section. The magnet 2a has magnetization in the direction perpendicular to the upper and lower bottom surfaces. The magnet 2b inclines the magnetization angle of the magnet 2a by 30 degrees. The magnet 2c tilts the magnet 2a by 60 degrees. The magnet 2d tilts the magnet 2a by 90 degrees. The magnet 2d has a magnetization direction parallel to the upper and lower bottom surfaces. Like the magnet 2, the magnet 3 also has four magnetization angles.
In the embodiment of the present invention, the magnet 2 constituting the outer peripheral side Halbach magnetic circuit 8 and the magnet 3 constituting the inner peripheral side Halbach magnetic circuit 7 are magnets having four different angles, respectively.

FIG. 3 shows how the outer peripheral side Halbach magnetic circuit 8 is rotated relative to the inner peripheral side Halbach magnetic circuit 7 to adjust the magnetic field strength inside the inner cover 6. The state of adjusting the magnetic field strength will be described with reference to FIG. In FIG. 2, the direction of the magnetic field of the Halbach magnetic circuit 7 on the inner peripheral side is on the right side as shown by an arrow. The strength of the magnetic field is assumed to be 1.
In FIG. 2, the direction of the magnetic field of the Halbach magnetic circuit on the outer peripheral side is on the right side as shown by the arrow. The strength of the magnetic field is assumed to be 1.

FIG. 3D shows the direction of the magnetic field of the magnetic circuit 1 of the magnetic separator when the directions of the magnetic fields of the inner peripheral side Halbach magnetic circuit 7 and the outer peripheral side Halbach magnetic circuit 8 are aligned to the right side in the figure. .. In this case, the magnetic field strength of the magnetic separator is 2, which is the sum of the magnetic field strength 1 of the inner peripheral side Halbach magnetic circuit 7 and the magnetic field strength 1 of the outer peripheral side Halbach magnetic circuit 8. The sum of the magnetic field strengths is the magnetic field strength of the double ring-shaped Halbach magnetic circuit 1 of the magnetic separation device 100.

FIG. 3E shows the magnetic field of the magnetic circuit (ring-shaped Halbach magnetic circuit) 1 of the magnetic separator 100 when the directions of the magnetic fields of the inner peripheral side Halbach magnetic circuit 7 and the outer peripheral side Halbach magnetic circuit 8 are reversed. There is. In this case, the magnetic field strength of the magnetic separator is 0 because the magnetic field strength 1 of the inner peripheral side Halbach magnetic circuit 7 and the magnetic field strength 1 of the outer peripheral side Halbach magnetic circuit cancel each other out.

When the outer peripheral side Halbach magnetic circuit 8 is rotated relative to the inner peripheral side Halbach magnetic circuit 7, the magnetic field strength of the magnetic separation device can be adjusted in the range of 0 to 2.

FIG. 4 is a magnetic separation column 10 constituting the embodiment of the present invention. The magnetic separation column 10 is composed of a tubular body 14 having a hollow portion and a magnetic material filter 12 arranged in the tubular body. The tubular body 14 is cylindrical and includes a large diameter portion 11 and a reduced diameter portion 13 on both ends of the large diameter portion.
A magnetic filter 12 is arranged on the large diameter portion 11.

Any magnetic filter can be used as long as it can efficiently adsorb impurities of the magnetic material when a magnetic field is applied from the outside. For example, glass wool, a magnetic wire mesh laminated in the axial direction, or a magnetic sphere may be filled in the magnetic separation column. It is desirable that the surface area of the magnetic filter is large. Further, the degree of filling of the magnetic filter into the cylinder may be appropriately set according to conditions such as the type of liquid to be flowed and the flow rate.

FIG. 5 is a plan view (K) and an MM cross-sectional view (L) of the magnetic separation device 100 (the magnetic separation column 10 is inserted and arranged on the inner peripheral surface side of the double ring-shaped Halbach magnetic circuit 1).
The case where the magnetic field strength applied to the magnetic separation column 10 is 0 is shown.

FIG. 6 is a cross-sectional view of a shaft in which the magnetic separation device 100 is mounted on a pipe 20 through which a liquid containing impurities of a magnetic material flows. The magnetization direction of the inner peripheral side Halbach magnetic circuit 7 and the magnetization direction of the outer peripheral side Halbach magnetic circuit 8 are matched to the right in the drawing, and a magnetic field is generated in the magnetic separation column 10 as shown by an arrow. A magnetic field is applied so as to be orthogonal to the flow of the liquid.
The magnetic field causes magnetic impurities to adhere to the magnetized magnetic filter. As a result, magnetic impurities in the liquid that has passed through the magnetic separation device can be reduced.

The magnetic separation device 100 of the present invention can continuously change the magnetic field strength in the magnetic separation column 10 by adjusting the magnetization direction of the outer peripheral side Halbach magnetic circuit 8 and the magnetization direction of the inner peripheral side Halbach magnetic circuit 7. it can. For example, when the magnetization methods of the inner peripheral side Halbach magnetic circuit 7 and the outer peripheral side Halbach magnetic circuit 8 are opposite (angle 180 degrees), the magnetic field in the magnetic separator 1 can be set to substantially 0 magnetic field. .. Further, assuming that the magnetization direction of the inner peripheral side Halbach magnetic circuit 7 and the magnetization direction of the outer peripheral side Halbach magnetic circuit 8 are the same direction (angle 0 degrees), the magnetic field strengths in the magnetic separator 1 are the same (maximum). Value) can be.

Further, if the magnetization directions of the inner peripheral side Halbach magnetic circuit 7 and the outer peripheral side Halbach magnetic circuit 8 are adjusted between the opposite directions and the same direction, the magnetic field strength can be adjusted between 0 magnetic field and the maximum value. It is possible.
In the present invention, the substantially zero magnetic field does not mean that the magnetic field is completely zero, but includes the influence of geomagnetism, variations in the magnetization direction of individual magnets when the magnetic circuit is actually assembled, leakage magnetic field, and the like. Even a weak magnetic field strength is called a substantially zero magnetic field.

FIG. 7 is a schematic view showing a state of back cleaning of the magnetic filter in the magnetic separation device 100. The directions of magnetization of the outer peripheral side Halbach magnetic circuit 8 and the inner peripheral side Halbach magnetic circuit 7 are reversed, and the strength of the magnetic field applied to the magnetic separation column is substantially zero. In this state, it is possible to remove metal impurities adhering to the magnetic filter in the magnetic separation column 10 by flowing wash water in the opposite direction on the magnetic separation column 10 as shown by an arrow. When performing a backwash, a separate pipe (not shown) may be used so that the liquid to be magnetically separated flows in the direction opposite to that at the time of magnetic separation.

FIG. 8 shows a plan view (O) and a QQ sectional view (P) of the plan view (O) of the magnetic separation device according to another embodiment of the present invention. The difference from the embodiment is the difference between the magnets constituting the inner peripheral side Halbach magnetic circuit 7 and the outer peripheral side Halbach magnetic circuit 8, and the other configurations are the same.

The outer peripheral side Halbach magnetic circuit 8 is composed of a magnet 81 having a trapezoidal cross section. The magnet 81 is two types of magnets: a vertically magnetizing magnet 81a having a magnetization angle perpendicular to the upper and lower bottoms of a trapezoid, and a parallel magnetization magnet 81b having a parallel magnetization angle. There are two types of magnets 91 that make up the inner peripheral side Halbach magnetic circuit 7, a vertical magnetization magnet 91a having a magnetization angle perpendicular to the trapezoidal upper and lower bottoms and a parallel magnetization magnet 91b having a parallel magnetization angle. Magnet.

The outer peripheral side Halbach magnetic circuit 8 and the inner peripheral side Halbach magnetic circuit 7 are composed of only two types of magnets having a magnetization angle perpendicular to or parallel to the upper bottom and the lower bottom, respectively. The upper and lower bases are parallel in the trapezoidal shape. In the processing of a magnet, it is relatively easy to process the magnet so as to have an angle of magnetization perpendicular to or parallel to a parallel straight plane (upper base and lower base of a trapezoid). Therefore, the manufacturing process can be simplified and the manufacturing cost can be suppressed.

FIG. 10 is a plan view (S) and a plan view (S) of the magnetic separation device according to still another embodiment of the present invention. FIG. 11 is a plan view (U, V) showing details of still another embodiment. The difference from the embodiment shown in FIG. 8 is that the distance between the vertically magnetized magnets 81a of the outer Halbach magnetic circuit can be changed. By making it variable, the Halbach magnetic circuit on the outer peripheral side is rotated, and the strength of the magnetic field applied to the magnetic filter is adjusted, and the distance of the vertically magnetizing magnet 8a is changed to make finer adjustments. Is possible. FIG. 10 shows a state in which the vertically magnetizing magnet 81a is closest to the magnetic field applied to the magnetic filter, and a gap 130 exists between the moving member 110 and the outer cover 120. Only the points different from FIG. 8 will be described.

A moving member 110 having a rectangular cross section is arranged on the lower bottom side of the perpendicularly magnetized magnet 81a. The moving member 110 and the perpendicularly magnetizing magnet 81a are joined by a known method. A groove 115 is formed on the inner peripheral surface side of the outer cover 120 so that the moving member 110 and the perpendicularly magnetizing magnet 81a can move in the radial direction, and the moving member 110 can be moved along the groove 115 by a known method. it can. 11 and 11 (U) show the case where the opposing perpendicular magnetization magnets 81a are closest to each other, and FIGS. 11 and 11 (V) show the case where the opposite perpendicular magnetization magnets 81a are closest to each other.

The magnetic field is adjusted as follows. In the state of FIG. 11, the directions of the outer peripheral side Halbach magnetic circuit and the inner peripheral side Halbach magnetic circuit are opposite, and the magnetic field applied to the magnetic filter can be made substantially zero. However, it may be difficult to set it to 0 due to variations in the magnetic characteristics of the magnet forming the Halbach magnetic circuit, variations in the processing dimensions of the magnets, and variations in the assembly of the Halbach magnetic circuit. At that time, by adjusting the distance of the vertically magnetizing magnet 81a constituting the outer peripheral side Halbach magnetic circuit, the magnetic field in the magnetic filter in the inner peripheral side Halbach magnetic circuit can be further brought closer to zero.

FIG. 12 is a cross-sectional view showing an example of a mechanism for moving the perpendicularly magnetized magnet 81a. A female screw 190 is formed on the moving member 150, and the outer cover 140 has a through hole 200. Each of the pair of bolts 160 passes through the through hole 200 and is screwed into the female screw 190 of the moving member.
A female screw 210 is formed on the outer cover 140, and the bolt 170 is screwed onto the female screw 210.

The pair of bolts 160 are used to move the perpendicular magnetizing magnet 81a away from the opposing perpendicular magnetization magnet 81a. In other words, by advancing the bolt 160, it is possible to move the vertically magnetizing magnet 81a joined to the moving member 150 away from the central axis direction of the magnetic separation device. In this case, the bolt 170 is retracted (outside the gap 130) in advance. On the other hand, when the vertically magnetizing magnet 81a is brought closer to the central axis direction of the magnetic separation device, the bolt 160 may be retracted and the bolt 170 may be advanced (advanced into the gap 170).
In the magnetic pole configuration of FIG. 12, the vertical magnetizing magnet 81a in the outer peripheral side Halbach magnetic circuit 8 and the vertical magnetizing magnet 91a on the inner peripheral side Halbach side repel each other. It is desirable to keep the bolt 170 in contact with the moving member 150 in order to maintain the position of.

The disclosed embodiments are exemplary in all respects and are not limited. The scope of the present invention is indicated by the scope of claims, and all modifications of the scope of claims and the scope of claims are included.

1 Double ring-shaped Halbach magnetic circuit 2 Magnet 3 Magnet 4 Outer cover 5 Inner cover 6 Inner cover 7 Inner peripheral side Halbach magnetic circuit 8 Outer peripheral side Halbach magnetic circuit 10 Magnetic separation column 11 Large diameter part 12 Magnetic filter 13 Reduced diameter part 14 Cylinder 20 Piping 30 U-shaped yoke 40 Magnet 81a Vertical magnetizing magnet 81b Parallel magnetizing magnet 91a Vertical magnetizing magnet 91b Parallel magnetizing magnet 100 Magnetic separator 110 Moving member 115 Groove 120 Outer cover 130 Void 140 Outer cover 150 Moving member 160 Bolt 170 Bolt 190 Female screw 200 Through hole 210 Female screw

Claims (5)

It has a magnetic separation column composed of a cylinder having a hollow portion and a filter made of a magnetic material arranged in the cylinder, and a double ring-shaped Halbach magnetic circuit that applies a magnetic field to the magnetic separation column. The double ring-shaped Halbach magnetic circuit is composed of an inner peripheral side Halbach magnetic circuit and an outer peripheral side Halbach magnetic circuit surrounding the inner peripheral side Halbach magnetic circuit, and the inner peripheral side Halbach magnetic circuit and the outer peripheral side Halbach magnetic circuit are A magnetic separator characterized by being relatively rotatable. A magnetic field is applied to the magnetic separation column composed of a cylinder having a hollow portion through which the liquid flows and a filter made of a magnetic material arranged in the cylinder, and the magnetic separation column so as to be orthogonal to the flow of the liquid. The double ring-shaped Halbach magnetic circuit has a heavy ring-shaped Halbach magnetic circuit, and the double ring-shaped Halbach magnetic circuit is composed of an inner peripheral side Halbach magnetic circuit and an outer peripheral side Halbach magnetic circuit surrounding the inner peripheral side Halbach magnetic circuit, and the inner peripheral side. A magnetic separator characterized in that the Halbach magnetic circuit and the Halbach magnetic circuit on the outer peripheral side are relatively rotatable. The outer peripheral side Halbach magnetic circuit and the inner peripheral side Halbach magnetic circuit are polygonal in cross-sectional view, and are trapezoidal so that the upper bottoms of a plurality of trapezoidal magnets face the center of the polygon in cross-sectional view. The magnetic separation device according to claim 1 or 2, wherein the legs are combined to form a magnetic separation device. There are two types of trapezoidal magnets in the cross-sectional view: a vertically magnetizing magnet having a magnetization angle perpendicular to the upper and lower bases and a parallel magnetizing magnet having a magnetization angle parallel to the upper and lower bases. The magnetic separator according to claim 3. The magnetic separation device according to claim 4, wherein the vertically magnetizing magnets are arranged to face each other, and the vertically magnetizing magnets of the outer peripheral side Halbach magnetic circuit can change the facing distance.

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