JP2954904B2 - Magnetic small piece and stirring method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a permanent magnet material whose residual magnetic flux density is too small, and as a material for electromagnets, a magnetic material having a residual magnetic flux density that is too large to be used is present in other magnets. The present invention finds that it has a peculiar performance and uses it for agitation and surface treatment in a magnetic field in which the direction of magnetic flux is periodically changed.

[0002]

2. Description of the Related Art Conventionally, there are two types of magnets: hard permanent magnet materials and soft electromagnet materials. The hard magnet materials include the maximum value of the energy product in the demagnetization curve of the second quadrant of the hysteresis loop, (HB). _max is 0.225MGOe
The above materials are used, Alnico 5 is about 10 MGOe, and a magnet material reaching as high as 40 MGOe, such as a rare earth magnet of 30 MGOe or more, and a rare earth sintered magnet of neodymium / iron / boron is developed. Was required. On the other hand, for soft electromagnet materials, pure iron, iron-cobalt alloy, iron-aluminum alloy,
Iron-nickel-permalloy, iron-silicon steel, composite ferrite, and the like are used. In each case, the maximum value of the energy product, (HB) _max , in the demagnetization curve in the second quadrant of the hysteresis loop is almost zero. Materials close to have been developed and used.

[0003]

SUMMARY OF THE INVENTION The inventor of the present invention has proposed a material for a hard permanent magnet whose width near the origin in a hysteresis loop is too wide, and a material for a soft electromagnet whose width near the origin in a hysteresis loop is too narrow. The fact that it behaves differently from soft and hard magnet materials has been found.
The purpose of this study is to study the technology for industrially utilizing this behavior.

[0004]

According to the structure of the present invention, the maximum value of the energy product in the demagnetization curve of the second quadrant of the hysteresis loop, (HB) _max, is 0.006 to 0.15 MGO.
e, a large number of magnetic small pieces in the range of e are housed in a non-magnetic container installed in a magnetic field in which the direction of magnetic flux is periodically changed, and a substance to be stirred is charged into the container to mix, stir, and wash. It is characterized by performing other surface treatments.

The present invention has found that a magnetic material having a small maximum energy product as a hard permanent magnet material and having a too large maximum energy product as a soft electromagnet material exhibits a special behavior. That is, a large number of bar-shaped small pieces made of the magnetic material of the present invention are scattered through a plate made of a non-magnetic material, and when a strong permanent magnet is placed below, the small pieces of the present invention are instantaneously arranged in the direction of the line of magnetic force, When the permanent magnet is moved, the permanent magnet moves in a straightforward manner, and all the small magnetic pieces follow the permanent magnet along the lines of magnetic force. At this time, there is little resistance in moving the permanent magnet. On the other hand, in the case of a small piece made of a hard or soft magnetic material for a conventional permanent magnet or an electromagnet, the pieces are gathered along the lines of magnetic force around the permanent magnet on the lower surface of the plate made of a non-magnetic material, but when the amount is large. Tend to be nodular and are difficult to arrange along the lines of magnetic force. A further significant difference is that the resistance of moving the permanent magnet on the lower surface is extremely large.

When various values were measured for various magnetic pieces and a hysteresis loop was drawn, the maximum value of the energy product, (HB) _max, was in the range of 0.006 to 0.15 MGOe. It has been found that it has the property of moving quickly in response to a change in the line of magnetic force.

In a magnetic stirrer conventionally used, a permanent magnet bar is rotated under a support plate, a flask is placed on the support plate, and a permanent magnet is charged in a thruster. The stirring force is generated by the rotation of the permanent magnet in the flask. However, when two permanent magnets are charged, the two permanent magnets come into close contact with each other, and the stirring effect is reduced. When a large number of the magnetic pieces of the present invention were placed in a flask and the permanent magnet below the support plate was rotated, each magnetic piece was independently rotated or vibrated, and the stirring efficiency was significantly improved. Also, when so-called magnetic stainless steel or soft iron is used, the magnetic small pieces interact with each other and the movement of each small piece is reduced, and a sufficient stirring effect cannot be obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The magnetic material of the present invention has a maximum energy product, (HB) _max of 0.006 to 0.15 MGO.
e, preferably 0.002 to 0.1 MGOe, more preferably 0.01 to 0.08 MGOe. As a material, an iron alloy is preferable, and stainless steel is particularly preferable in terms of low chemical reactivity. The shape is not limited, and includes a rod shape, a spherical shape, a plate shape, and the like, with a diameter of 0.2 to 1.5 mm and a length of 3 to 1.
A 0 mm rod is preferred. Maximum energy product, (H
B) _max is less than 0.06 MGOe or 0.15 MGOe
Is exceeded, it becomes difficult to move independently in a magnetic field in which the direction of the magnetic flux changes periodically, and the efficiency of stirring and surface treatment decreases.
Magnet pieces whose maximum energy product is within the scope of the present invention are:
A favorable movement occurs in a magnetic field in which the direction of the magnetic flux changes periodically.

In general, stainless steel is a non-magnetic material, but a part of the austenitic crystal structure may be converted to a martensite crystal structure by quenching and then cold rolling. A stainless steel material partially converted to a martensitic crystal structure is preferable. If 40 to 80% by weight, preferably 45 to 70% by weight is converted to a martensitic crystal structure, it can be used as a magnet piece of the present invention. As a stainless steel exhibiting the maximum energy product within the range of the present invention by cold rolling, according to tests by the present inventors, SUS27 (AISI 304) according to JIS standard, SUS29 (AISI 321) according to JIS standard, and SUS32 according to JIS standard. (AISI 316), JIS standard SUS39 (AISI 301), JIS standard SUS40 (AISI 302), AISI 302
B, AISI 303, AISI 303Se, AIS
I 308, AISI 317, AISI 348, A
ISI 201, AISI 202 and the like. Other stainless steels did not show magnetism even after cold rolling within the range of tests performed by the present inventors.

[0010] Made of stainless steel JIS29, diameter 0.5m
The magnetization of a wire having a length of 5 mm and a length of 5 mm was measured at ± 2 kOe using a TOEIVSM-3 vibrating sample magnetometer. FIG. 1 shows the hysteresis loop obtained as a result of the measurement. FIG.
The maximum value of the energy product, (HB) _max, was 0.015 to 0.04 MG · Oe.

In order to obtain a magnetic field in which the direction of the magnetic flux is periodically changed, a permanent magnet is used, and the magnetic field is obtained by rotating the permanent magnet. The rotating permanent magnet may be the lower surface, the periphery, or the center of the material to be mixed or treated, or a combination of these, but the rotating permanent magnet and the material to be treated are reliably separated. I need to do that. In addition, a magnetic field in which the direction of the magnetic flux changes periodically can be obtained using an electromagnet. For example, by providing a coil-shaped winding in an iron core and applying an AC power to the winding, a strong magnetic field is obtained inside the winding. The magnetic field generated by the coiled winding may be provided on the lower surface of the container containing the substance to be mixed, stirred or surface-treated, provided on the outer periphery, or provided with a projection for containing the winding inside the container. good. In short, it suffices that a container for storing the object to be processed exists in the magnetic field of the winding to which the AC power is applied.

The magnetic particles of the present invention can be used for various purposes. For example, an experiment was performed using a magnetic stirrer conventionally used as shown in FIG. Reference numeral 1 denotes a variable motor, which rotates the permanent magnet 3 mounted on the lower surface of the support plate 2 at an arbitrary speed by the rotation of the variable motor 1. A large number of magnetic pieces of the present invention were charged in the flask 4 in place of the permanent magnet charged for stirring. As the permanent magnet 3 rotates, the direction of the magnetic flux periodically changes at the bottom of the flask 4, but each magnetic piece independently vibrates and rotates without being affected by other magnetic pieces, and the conventional one permanent A vigorous stirring effect that cannot be obtained with a magnet is obtained. This device is used for agitation or mixing of highly viscous fluids such as paint, when mixing a large amount of powder with a small amount of powder, or when dispersing a solid evenly in a liquid. It can be applied to any combination of liquid, liquid and liquid.

A magnetic field in which the direction of the magnetic flux is periodically changed can be formed by an AC power supply. As shown in FIG. 3 or FIG. 4, a winding 6 housed inside the iron core 5 may be provided around the container, and an AC power may be applied to the winding 6. The vicinity of the winding 6 becomes a strong magnetic field, and the space surrounded by the plurality of windings 6 becomes a magnetic field that periodically changes the direction of the magnetic flux. The strength of the magnetic field is strong near the winding in the space, and the intensity of the magnetic field decreases at the center in inverse proportion to the square of the distance.

When two or more substances to be mixed and articles to be surface-treated are charged together with the magnetic pieces of the present invention in this space, the magnetic pieces of the present invention vibrate and rotate independently, and two or more kinds of substances are rotated. Are uniformly mixed, or the surface of an article having a predetermined shape is washed, foreign substances adhering to the surface are cleaned, and fine burrs and the like are removed. The processing apparatus of the present invention is not limited to the apparatuses shown in the drawings, and a magnetic field that is periodically converted using a permanent magnet or an electromagnet can be formed in a certain space. In this space, the magnetic pieces of the present invention individually vibrate. As long as it can be rotated, it can be used for stirring, mixing, and surface treatment regardless of a batch type or a continuous type.

[0015]

Example 1 Paint was used as a substance to be stirred. A slight amount of green paint was blended with white paint to prepare a slightly greenish white paint. In this case, 100 g of white paint and 1 g of green paint are added to the flask of FIG.
Further, one magnetic piece 11 of the present invention having a diameter of 1 mm and a length of 5 mm was gripped and charged. The magnetic piece was SUS27 according to JIS, and (HB) _max was 0.02 to 0.035 MGOe. When the variable motor 1 is rotated at 5000 rpm, the magnetic pieces vibrate violently, and two types of viscous paint are applied for about 1.5 times.
In minutes, a homogeneous white paint with a pale greenish tint was obtained. As a stirring means, a pale greenish white paint was prepared using the apparatus of Example 1 except that one permanent magnet having a diameter of 1 cm and a length of 4 cm was used instead of the magnetic piece of the present invention. It took about 11 minutes to get.

Example 2 Using the apparatus shown in FIG. 3, a fertilizer containing soluble nitrate, soluble phosphate and soluble potassium in powder form was compounded.
Reference numerals 7a, 7b and 7c denote hoppers, which flow into the screw feeder 9 rotated by the motor M via the flow control valves 8a, 8b and 8c, respectively, and fall into the mixing cylinder 10 while being roughly mixed. A plurality of coiled windings 6 are arranged around the mixing cylinder 10. The iron core 5 was arranged so as to surround the mixing cylinder 10 and the winding 6 made of a non-magnetic material. Since the present embodiment is of a continuous type, the mixing cylinder 10 corresponds to a non-magnetic container.

A three-phase alternating current is applied to the winding, and the magnetic poles on the same horizontal plane are arranged so as to simultaneously convert S → N → S → N. The length of the mixing cylinder 10 depends on the powder to be mixed,
If necessary, the windings can be stacked in several stages, but when the vicinity of the mixing cylinder of one winding 6 is an S pole, a state in which the lower winding 6 is also an S pole is preferable. . Mixing cylinder 10
A large number of magnetic small pieces 11 were charged therein.

As the magnetic piece 11, the same magnetic piece as in Example 1 was used. When the winding 6 is energized, the magnetic pieces in the mixing cylinder 10 are attracted by a strong magnetic field and head toward the mixing cylinder wall.
Since the magnetic field is converted immediately, a force for reversing is applied, and the magnetic poles are instantaneously reversed, so that the individual magnetic pieces vibrate or rotate violently. The powder falling between the magnetic pieces vibrating and rotating violently was disturbed by the magnetic pieces and quickly and uniformly mixed. A filter 12 has a function of separating the magnetic small piece 11 and the mixed fertilizer and dropping the mixed fertilizer. The dropped mixed fertilizer was stored in the mixture storage tank 13 by the discharge screw 15. 14 is a discharge valve. At this time, if a magnetic material whose maximum energy product is out of the range of the present invention is used, the magnetic material becomes a nodular shape and the stirring effect cannot be obtained. Even if it did not become a lump, the movement was slow and the stirring efficiency was reduced.

Embodiment 3 FIG. 4 is a longitudinal sectional view of Embodiment 3, and FIG. 5 is a sectional view taken along line VV of FIG. In this embodiment, an electronic component chip was used, and trace amounts of oil and dust attached to the chip were washed with pure water. Reference numeral 25 denotes a cleaning tank made of a non-magnetic material, and a processing liquid suction pipe 16 is provided at the center. The liquid that has passed through the processing liquid suction pipe 16 in the cleaning tank 25 flows into the processing liquid suction pipe,
At this time, when the magnetic pieces 11 are mixed, the processing liquid suction pipe 1
6 and is caught by an upper filter 17 provided at the upper part. The liquid flowing into the processing liquid suction pipe 16 is returned to the cleaning tank 25 by the circulation pump P and rises.

A plurality of baskets 18 are installed in the washing tank 25,
At the bottom center of the basket 18, a rotating shaft 19, which slowly rotates by a motor installed at the top, was fixed. As in the second embodiment, the cleaning tank 25 is provided with the windings 6 disposed therearound and further surrounded by the iron core 5. Reference numeral 20 denotes a flexible rotating shaft, reference numeral 21 denotes a support sleeve, and reference numeral 22 denotes a mounting socket. An electronic component 23 to be washed and a large amount of magnetic small pieces 11 used in Example 1 were charged into the basket 18, and pure water was used as a liquid. 3 for winding
When a phase alternating current was applied, a magnetic field was generated in the cleaning tank 25 that drastically changed the direction of the magnetic flux. This magnetic field is large at the peripheral portion of the cleaning tank 25 and becomes weaker as approaching the central portion.

As in the case of the second embodiment, the magnetic pieces vibrate violently under the influence of the periodically converted magnetic field, and dirt and foreign matter adhering to the electronic component 23 were washed away. Since the washing power is strong at the periphery of the basket 18 and weak at the center, the basket 18 is slowly rotated to avoid uneven washing power. Since the magnetic particles had a large specific gravity of 7 to 8, they were washed in an upward flow so that the washing power at the bottom and the top of the basket did not differ.
That is, pure water for cleaning was supplied from the bottom of the cleaning tank 25 by the circulation pump P and the circulation flow rate control valve 27, and was sucked from the upper part of the processing liquid suction pipe 16.

Reference numeral 24 denotes a drainage tank, and reference numeral 26 denotes a drainage valve. The cage 18 can be easily removed by removing the mounting socket 22 and rotating the flexible rotation shaft 20 and the support sleeve 21. In this example, the dirt adhering to the electronic components was completely washed with pure water, and burrs on the substrate were removed. In addition, since the cleaning liquid is pure water, it was dried as it was to obtain a product.

[0023]

According to the present invention, when only two or more magnetic materials having a specific maximum energy product are placed in a magnetic field which alternates periodically, the magnetic materials do not affect each other. In addition, they have found out that they exhibit different behaviors under the influence of a magnetic field, and by utilizing this characteristic, it has become possible to use them for agitation and mixing of various materials or to efficiently perform surface treatment.

[Brief description of the drawings]

FIG. 1 is a hysteresis loop of a magnetic piece of the present invention measured using a TOEI VSM-3 vibrating sample magnetometer.

FIG. 2 is a sectional view of a conventional magnetic stirrer using a magnetic piece of the present invention instead of a conventional stirring element.

FIG. 3 is a cross-sectional view of a mixing apparatus using the magnetic small pieces of the present invention.

FIG. 4 is a longitudinal sectional view of a cleaning apparatus using the magnetic small pieces of the present invention.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable motor 2 Support plate 3 Permanent magnet 4 Flask 5 Iron core 6 Winding 7 Hopper 8 Flow control valve 9 Screw feeder 10 Mixing cylinder 11 Magnetic small piece 12 Filter 13 Mixture storage tank 14 Discharge valve 15 Discharge screw 16 Treatment liquid suction pipe 17 Upper part Filter 18 Basket 19 Rotation axis 20 Flexible rotation axis 21 Support sleeve 22 Mounting socket 23 Electronic components 24 Drain tank 25 Wash tank 26 Drain valve 27 Circulating water volume adjustment valve

Claims (9)

(57) [Claims] 1. The maximum value of the energy product, (HB) _max , in the demagnetization curve of the second quadrant of the hysteresis loop is 0.0.
A magnetic piece, which is in the range of 06 to 0.15 MGOe. 2. A non-magnetic container is positioned in a magnetic field in which the direction of a magnetic flux changes periodically, and a substance to be stirred is placed in the container.
The maximum value of the energy product in the demagnetization curve in the second quadrant of the hysteresis loop, (HB) _max is 0.006 to 0.15
A stirring and mixing method comprising charging a large number of magnetic pieces in the range of MGOe. 3. The maximum value of the energy product in the demagnetization curve of the second quadrant of the hysteresis loop of the magnetic piece, (HB)
3. The stirring and mixing method according to claim 2, wherein _max is in the range of 0.01 to 0.1 MGOe. 4. A non-magnetic container is positioned in a magnetic field in which the direction of a magnetic flux changes periodically, and a substance to be stirred is placed in the container.
A stirring and mixing method comprising charging a number of magnetic small pieces made of an iron alloy having a martensitic crystal structure ratio in the range of 40 to 80% by weight. 5. A non-magnetic container is positioned in a magnetic field in which the direction of magnetic flux is periodically changed, and a material to be surface-treated, a surface treatment liquid, and a demagnetization curve in a second quadrant of a hysteresis loop are placed in the container. And (HB) _max is charged in a range of 0.006 to 0.15 MGOe. 6. The surface treatment method according to claim 4, wherein the surface treatment method is a cleaning treatment method for an object to be treated. 7. A non-magnetic container is positioned in a magnetic field in which the direction of magnetic flux is periodically changed, and the ratio of the object to be treated, the surface treatment liquid, and the martensitic crystal structure is 40 to 40 in the container. A surface treatment method comprising charging a large number of magnetic pieces in the range of 80% by weight. 8. The surface treatment method according to claim 7, wherein the surface treatment method is a cleaning treatment method for an object to be treated. 9. The maximum value of the energy product in the demagnetization curve of the second quadrant of the hysteresis loop of the magnetic piece, (HB)
9. The surface treatment method according to claim 6, wherein _max is in the range of 0.01 to 0.1 MGOe.