JPH05256581A - Magnetically lifting apparatus for feebly magnetic substance such as sintered ore - Google Patents

Abstract

PURPOSE:To provide the title apparatus which can effectively lift even a feebly magnetic substance such as a sintered ore through small-sized, light-weighted and low-powered constitution, by a method wherein the magnetic flux of permanent magnets is allowed to overlap on the magnetic circuits of an electromagnet and the ratio of the height of an electromagnetic coil to the distance between magnetic poles is specified. CONSTITUTION:A magnetic circuit B is composed of an E-shaped magnetic field-generating device 1 (E-shaped magnet) and a sintered ore 2 (feebly magnetic substance), which are opposed to each other through a gap. A yoke (iron core frame) 3 and a racetrack type coil 4, with which central magnetic poles are surrounded, are also provided. When a subject to be lifted (sintered ore) is the feebly magnetic substance, most of magnetic flux is distributed between magnetic poles and a magnetic circuit B' is established, and hence magnetism does not act on the subject. In order that the magnetism is allowed to act on the subject, the ratio of the height (h) of an electromagnetic coil to the distance (z) between the magnetic poles is preset in the range of 1.5 to 3.5. In addition, permanent magnets 6 are bonded to the pole ends 5 of the electromagnet and the magnetic flux is allowed to overlap each other. Furthermore, the length of the permanent magnets 6 bonded to outer and inner poles on the electromagnet is varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is a DL type (Dweight)
Lloyd Type) and GW formula (Greena)
The present invention relates to a magnetic levitation device for a weak magnetic material such as a sinter, which is used for the production of iron ore sinter by an air downward suction type sintering machine such as Walt Type) and which is small in size and lightweight for power saving. It is also applicable to the downward suction sintering method other than iron ore and non-contact floating of general weak magnetic materials.

[0002]

2. Description of the Related Art In a sintering operation using an air downward suction type sintering machine, a charging device in which a plurality of steel plates (stand materials) are arranged when charging a sintering raw material is recently disclosed in Japanese Patent Laid-Open No. 2-254125. It describes an effective method that prevents compression of the lower layer raw material due to shrinkage at the time of sinter ore production and does not deteriorate the quality, but the stand material used for support must be replaced after a certain period of time due to wear. There are problems such as.

Therefore, the present inventors have utilized electromagnetic force to
Considering a sintering method in which sintering is held and floated in a non-contact manner, application was filed as Japanese Patent Application Nos. 2-242544 and 3-124532.

That is, FIG. 8 shows an example of operating the sintering method of the present invention with a DL type sintering machine. Sintering raw material surge hopper 7
The sintering raw material stored in 1 is charged into the sintering machine 8 by the raw material charging device 9 and then ignited in the ignition furnace 10 and sequentially sintered from the surface layer to the lower layer, but passes through the ignition furnace 10. After that, as the strand progresses, sintering is completed from the upper layer of the sintering bed,
After being solidified and cooled, a sintered ore (sinter cake) 2 is formed.
The one-dot chain line in FIG. 8 indicates the combustion melting zone 1 in which the sintering reaction is performed.
1, the upper part of this line is the so-called sintered ore part where the sintering reaction is completed, and the lower part of this line is the part in the raw material state.

By the magnetic levitation device 12 installed on the upper part of the pallet 8-1, by applying a levitation force to the sinter cake which is less than or more than the resultant force of the gravity of the sinter cake and the downward force applied to the sinter cake by the suction pressure of the blower. By reducing the gravity of the sinter cake or holding or peeling the sinter cake and floating it, the sintering below the sinter cake was preheated with the sinter cake released from the gravity from above. Air can be used to drive the reaction. 13 is a mounting stand and 14 is a sintering completion point.

Since iron ore sinter (sinter cake) is a weak magnetic material, it has poor magnetic properties, and since it needs to be held and levitated in a non-contact manner, a conventional conductor wire made of copper or aluminum is in the same tubular shape. In order to generate a sufficiently strong magnetic field with the electromagnet wound around, enormous amount of electric power and cooling water are required, and it is a problem that it becomes a large-scale facility.

In the case of a single permanent magnet, the highest residual magnetic flux density of 1.3 is currently commercialized.
Although it is about Tesla, when a magnetic circuit with a gap is formed, the generated magnetic flux is greatly attenuated, and it is difficult to generate the necessary electromagnetic force.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a magnetic field generator having a magnetic circuit capable of obtaining a strong magnetic field in a void with low power consumption, small size and light weight, and a non-contact type. The present invention provides a magnetic levitation device that holds and levitates a weak magnetic material such as a sintered ore.

[0009]

The apparatus of the present invention comprises a weak magnetic material such as sinter ore that forms a gap and is opposed to at least a permanent magnet, an electromagnet and a yoke thereof to magnetically couple the magnetic field to the gap. In a magnetic field generator that generates a magnetic field, a permanent magnet attached to the surface of a yoke facing a weak magnetic body, effectively superimposes the magnetic flux of the permanent magnet on the magnetic circuit of the electromagnet, and By making the ratio of the coil height of the electromagnet to the magnetic pole interval about 1.5 to 3.5 times, the structure is such that the magnetic flux is effectively concentrated on the surface layer of the weak magnetic material. A magnetic levitation device for weak magnetic materials such as sinter, characterized by having a structure in which the magnetic flux at the end of the electromagnet is improved by changing the attachment length (height of the permanent magnet) of the permanent magnet installed in the is there. The yoke is an iron core frame of an electromagnet that forms a part of a magnetic circuit, and a magnetic material having a high saturation magnetic flux density and a high magnetic permeability, such as permalloy, silicon steel, and permendur, is used.
The magnetic pole interval means a length obtained by adding a thickness of a heat insulating material to the coil width of the electromagnet.

[0010]

The operation of the present invention will be described with reference to the drawings.

As shown in FIG. 1A, in the present invention, for example, a magnetic circuit B shown by a solid line has an E type magnetic field generator (E type magnet) 1 shown in FIG.
And sintered ore (weak magnetic material) 2. Reference numeral 3 is a yoke (iron core frame), and 4 is a racetrack type coil surrounding the central magnetic pole. FIG. 1 (a) is a schematic I of FIG. 1 (b).
(A) -I (I) is a cross-sectional explanatory view taken in the direction of the arrow, and FIG.
2B is a top view of FIG. 2.

When the object to which the electromagnetic force is applied is a ferromagnetic material, a sufficient magnetic flux (electromagnetic force) can be obtained in a non-contact manner by making the magnetic poles wider than the gap and widening the width of the magnetic poles. However, when the target to which the electromagnetic force is applied is a weak magnetic material, the magnetic characteristic of the target is close to that of air, so that as shown in FIG. It does not act on the target (sintered ore) because it constitutes'. Therefore, as shown in FIG. 1 (a), first, the magnetic pole spacing is made wider than that of the air gap, and at the same time, the width of the frame and the height ratio of the coil of the electromagnet are optimized, so that the solid line in FIG. In this way, the magnetic flux is concentrated inside the sintered ore (weak magnetic material) 2, and the electromagnetic force (attracting force) can be increased. When the lower end portions on both sides of the yoke (iron core frame) 3 are S poles, the central lower end portion of the iron core frame is an N pole, and the S pole and the N pole respectively exert magnetic levitation force.

As shown in FIG. 2, the magnetic flux (electromagnetic force) generated by the permanent magnet 6 is adhered to the magnetic pole end 5 of the E-type electromagnet to suppress the energizing current of the electromagnet to a low level due to the superposition effect of the magnetic flux. ) Is not reduced. Further, when the energizing current is constant, the electromagnetic force can be greatly increased.

Further, as shown in FIG. 1 (a) and FIG.
The ratio of the coil height h of the electromagnet to the magnetic pole spacing z is 1.5 so that the main part of the generated magnetic flux is effectively injected into the sinter.
About 3.5 times is preferable. The coefficient is related to the required magnetomotive force and the magnetomotive force (current density) per unit area,
The formula is shown in Equation 1.

[0015]

[Equation 1] However, z magnetic pole spacing h coil height of electromagnet k correction coefficient (5.5 to 7.0) X ₁ magnetomotive force n ₁ magnetomotive force coefficient (0.16 to 0.20) X ₂ electromagnetic density n 2 electromagnetic density coefficient (0 12-0.16).

That is, as shown in FIG. 3, when the magnetomotive force is changed by setting the distance between the E-type magnetic field generator and the load (sinter ore) to 30 mm or 50 mm, the coil height h of the electromagnet is set to the magnetic pole interval z. When it is 1.5 to 3.5 times, the generated electromagnetic force per unit acting area is the maximum. If possible, about 2.0 to 2.5 times is desirable. This is because as the height h increases, the leakage magnetic flux penetrating the electromagnet coil increases, and when the magnetic pole interval z is increased, the magnetic resistance increases.

FIG. 4 shows the effect on the electromagnetic force when the width of the inner pole is increased or decreased while keeping the overall size of the E-type magnetic field generator shown in FIG. In order to reduce the magnetic flux saturation of the yoke and the attenuation of the magnetic flux just below the inner pole, the electromagnetic force is maximum when the gap distance is 30 mm and the width of the inner pole is 100 to 150 mm. It should be noted that the electromagnetic force when the energizing current is zero, only the electromagnet, and the magnetomotive force is increased is shown, but the effect of compounding the magnet and the like can be seen. The width of the inner pole must be taken into consideration by the magnetic characteristics of the frame and the magnetomotive force,
Magnetic saturation of the center of the inner pole (1.6-1.
8 Tesla), and the above values are based on the assumption of an iron frame. In principle, the outer pole should be about half the thickness of the inner pole.

Since the voids and the weakly magnetized sintered ore portion occupy a large proportion on the magnetic circuit, as shown by the line a in FIG. 5, which is the magnetic flux density distribution of the sintered ore surface layer of the E-type electromagnet, At the same time that the strength of the magnetic field weakens, the magnetic flux density on the surface of the sinter tends to have a distribution such that the area immediately below the inner frame of the electromagnet becomes stronger and the area immediately below both end frames decreases.

Therefore, the magnetic flux is superposed on the surface (on the magnetic circuit) of the magnetic pole end of the magnetic field generator by bonding a high performance permanent magnet such as a rare earth permanent magnet such as SmCo type or NdFeB type. As a result, as shown by the line b in FIG. 5, which is the magnetic flux density distribution of the sintered ore surface layer of the E-type electromagnet when the permanent magnets having the same attachment length (20 mm) are attached to the inner pole and the outer pole, The density increases sharply.

FIG. 6 shows the electromagnetic force characteristics when various practical permanent magnets of Alnico type, SmCo type and NdFeB type are used in the E-type magnetic field generator shown in FIG.・ The above-mentioned high performance adopted this time [for example, residual magnetic flux density Br = 1.1T (tesla); coercive force Hc =
6.76 × 10 ⁵ A / m; reversible permeability Mew Gamma =
1.3] A permanent magnet.

Next, when the distance between the permanent magnet and the load (sintered ore) is constant, the sticking length of the permanent magnet is preferably about 20 to 50 mm when a rare earth permanent magnet is used, and is less than that. Has a low effect of superimposing magnetic flux, and even if the sticking length is longer, the effect of superimposing does not improve so much, and in terms of cost, it is cheaper to generate with an electromagnet.

FIG. 7 shows the electromagnetic force characteristics when the sticking length of the permanent magnet is changed to the outer pole and the inner pole individually or collectively (whole). Referring to FIG. 7, in the hybrid magnet using the Sm.Co rare earth magnet in combination, the inner pole / outer pole width is 120 mm / in the E-type electromagnet structure shown in FIG.
The influence of the sticking length of the permanent magnet on the electromagnetic force characteristics when the length is 60 mm is shown. When the sticking length is 50 mm or more, the increase in electromagnetic force is moderate. Further, since the effect of the permanent magnet attached to the inner pole is larger than that of the permanent magnet attached to the outer pole, it is desirable to set the length of the outer pole permanent magnet to about 20 mm and the inner pole to about 50 mm. As a result, expensive permanent magnets can be eliminated.

The magnetomotive force is about 30,000 AT.

In FIG. 5, when using permanent magnets of substantially the same amount, the permanent magnet attached to the outer pole is longer than the inner pole (inner pole length 20 mm, outer pole length 50 m).
m) the magnetic flux density distribution of the surface layer of the sintered ore of the E-type electromagnet c
As shown by the d-line, which is the distribution when the line and the inner pole are made longer (inner pole length 50 mm, outer pole length 20 mm), the permanent magnet attached to the inner pole is made longer than the outer pole as a whole. It is possible to improve the magnetic flux density and prevent the magnetic flux from decreasing at the ends. As a result, a uniform and strong magnetic flux acts over the entire surface of the sintered ore, and the generated electromagnetic force becomes stronger.

If the air gap distance is constant, the permanent magnet attachment level should be set so that it does not protrude beyond the level of the electromagnet on the surface of the sintered ore when the gap is constant, so that the decrease in magnetic flux density due to the gap can be prevented. It is effective.

With the above operation, the magnetic flux density and the magnetic flux distribution on the surface of the sintered ore formed between the magnetic field generator and the sintered ore are improved, and the electromagnetic force (attraction force) of the sintered ore to the magnetic generator is improved. )
Can be increased.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

Component: T. Fe: 52.47%, CaO:
_{7.35%, Si0 2: 5.27%} , Al 2 O 3: 2.
33%, MgO: 1.04% and C: 2.89% sintering raw materials were prepared, and the following examples were performed.

[0029]

First Embodiment As a magnetic field generator (magnet) 1 of the present invention, a magnet composed of a yoke (iron core frame) 3 to which a permanent magnet 6 is attached as shown in FIGS. 1 and 2 and a racetrack type coil 4. Was prepared to float the sinter.

Magnetic field generator (magnet) 1 of the present invention
Has a configuration as shown in Table 1. A racetrack type composite magnet having a width of 370 mm, a length of 870 mm (yoke length of 700 mm) and a height of 290 mm was placed 30 mm away from the sintered ore. The composite magnet is a Sm / Co permanent magnet (magnet width 120 mm for inner pole installation, magnet width 60 for outer pole installation).
mm, pasting length 30 mm), 30000 AT electromagnet (coil width 65 mm thickness, coil height 220 mm,
Insulation material thickness included) and carbon steel for machine structure (SC material)
A magnetic circuit was constructed from the yoke of, and the one having its own weight of 600 kg was used.

[0031]

[Table 1]

As a result of applying an electromagnetic force to the sinter with a gap of 30 mm, it exhibited the ability to levitate about 210 kg / unit at a power consumption of 4.5 kW.

[0033]

Comparative Example 1 A conventional electromagnet having the same structure as in Example 1 was prepared except that the permanent magnet portion was changed to an iron yoke.

[0034]

[Table 2]

As shown in Table 2, in the conventional electromagnet, the electromagnetic force is 12 even when the magnetomotive force is the same as that of the composite magnet.
It was 0 kg / unit, and it was not possible to obtain the same level of electromagnetic force as that of the present invention. Further, in order to obtain the same level of electromagnetic force, a magnetomotive force of 50,065 AT was applied in a short time.
As a result, the power consumption is 12.5 kW / unit (about 3 of the present invention.
It was found that the power consumption was larger than that of the magnet of the present invention. In order to be able to use 50,065AT with continuous rating, the size and weight are further increased.

[0036]

Example 2 A magnetic levitation sintering operation device as shown in FIG. 8 was prepared. A magnetic levitation device 12 as shown in FIG. 9 was installed. The magnet 1 shown in Table 3 obtained by scaling up the magnetic field generator (magnet) of the present invention used in Example 1 is
One set was set up, and one set was set above the pallets (8-1, etc.) of the sintering machine 8 by the installation stand 13.

[0037]

[Table 3]

The excitation range was 35 m from the exit side of the ignition furnace 10 to the entrance side of the mine. The gap sensor 16 is an ultrasonic type, and the magnet lifting device 15 is an electric lifting device that can be lifted manually. The energizing current value is calculated from the control set power and the gap, and the energizing current to the magnet 1 is adjusted via the main power supply facility 17 to control the set electromagnetic force, and the size of the gap is set to 30 mm by the magnet lifting device 15. The magnetic levitation force was controlled and adjusted.

Using a DL sintering machine 8 having a sintering area of 180 m ² (3 m width × 60 m strand length), a layer thickness of 550 mm,
Approximately 15 m after leaving the ignition furnace 10 as shown in FIG. 8 when performing a sintering operation at a negative pressure of 1,000 mmAq by suction of a blower.
At the temperature of 240 mm below the surface of the sinter cake
A magnetic levitation device 12 as shown in FIG. 9 was installed at intervals of 1 m from 00 ° C .; the thickness of the sinter cake was 200 mm) to the BTP (sintering combustion completion point) 14 about 50 m after the ignition furnace.

While controlling the gap between the surface of the sinter cake and the magnetic pole tip to 30 mm, a magnetic levitation force corresponding to the total amount of the negative pressure due to the suction of the blower applied to the combustion melting zone 11 and the weight of the sinter cake generated is applied. After leaving the ignition furnace 10, the sinter cake generated by the progress of sintering was applied in a region from about 15 m from the ignition furnace 10 to the BTP, and the gravity applied to the combustion melting zone 11 was reduced to perform the sintering. Incidentally, about 15 m after leaving the ignition furnace 10, the magnetic levitation force was 140 kg / unit and the energizing current was 56 A, and the magnetic levitation force was 720 kg / unit and the energizing current was 290 A in the immediate vicinity of the BTP.

The power consumption per ton of the sintering raw material was 5.6 kWh.

Normally, the layer thickness after leaving the ignition furnace 10 is about 1 near the mine ore because the shrinkage progresses with the progress of sintering.
In contrast to the shrinkage of 00 mm, the shrinkage is 25 in this embodiment.
It became mm.

FIG. 10 shows the result of the combustion test of this example.
In the figure, the base is the operation result without magnetic levitation. The productivity was improved by about 30% when the magnet was applied as compared with the case where the magnet was not applied.

FIG. 11 shows the amount of NOx produced per hour. The amount of NOx produced was reduced by about 24% when the magnetism was applied compared to when the magnetism was not applied (base).

[0045]

Comparative Example 2 In order to perform magnetic levitation sintering using a conventional electromagnet in the same manner as in Example 2, it is necessary to upsize or increase the number of electromagnets, and the power consumption is about 4 as well.
~ 5 times more.

[0046]

As described above, compactness, light weight, low power consumption, and in some cases, no equipment such as a water cooling device are required, and the magnetic field strength is increased in the required space, and it is possible to use a weak magnetic material for sintering. A magnetic levitation device with extremely high practicality that can hold and levitate even if there is is realized.

[Brief description of drawings]

FIG. 1 (a) is an explanatory diagram showing a magnetic circuit according to the present invention, and FIG. 1 (a) is a schematic I of FIG. 1 (b).
(A) -I (I) is a cross-sectional explanatory view taken in the direction of the arrow, and FIG.
2B is a top view of FIG. 2. Further, it is an explanatory view of magnetic circuits B and B ′ in the conventional electromagnet and the electromagnet of the present invention.

FIG. 2 is an example of a composite magnet used in the present invention,
It is a perspective view of an E-type magnetic field generator (E-type magnet).

FIG. 3 is an explanatory diagram of a change in electromagnetic force depending on a ratio between a coil height h of an electromagnet and a magnetic pole interval z.

FIG. 4 is a graph showing the influence of the inner pole width of the E-shaped magnet on the electromagnetic force characteristics.

FIG. 5 is a graph showing a magnetic flux density distribution in a surface layer of a sintered ore of an E-type electromagnet and a composite magnet having a permanent magnet attached thereto.

FIG. 6 is a graph showing electromagnetic force characteristics of various permanent magnets.

FIG. 7 is a graph showing electromagnetic force characteristics of a hybrid magnet depending on a permanent magnet attachment length.

FIG. 8 is an explanatory diagram showing an example of an apparatus for carrying out the sintering operation method of the present invention using a DL type sintering machine.

FIG. 9 is a schematic perspective view showing an example of a magnetic levitation device of the present invention in which a magnet is installed above a pallet.

FIG. 10 is a graph showing combustion test results (productivity) with and without magnetic levitation.

FIG. 11 is a graph showing a combustion test result (NOx generation amount per hour) with and without magnetic levitation.

[Explanation of symbols]

 1 E type magnetic field generator (E type magnet) 2 Sinter ore (weak magnetic material) 3 Yoke iron (iron core frame) 4 Race track type coil 5 Magnetic pole tip 6 Permanent magnet 7 Sintering raw material surge hopper 8 Sintering machine 8 -1 Pallet 9 Raw material charging device 10 Ignition furnace 11 Combustion melting zone 12 Magnetic levitation device 13 Installation platform 14 Sintering combustion completion point 15 Magnet lifting device 16 Gip sensor 17 Main power supply facility B Magnetic circuit shown by solid line B'Indicated by broken line Magnetic circuit z Magnetic pole spacing h Electromagnetic coil height

Claims (1)

[Claims] 1. A magnetic field generator that magnetically couples a weak magnetic material such as sinter ore, which forms a gap and faces each other, with at least a permanent magnet, an electromagnet and a yoke thereof to generate a magnetic field in the gap. A permanent magnet attached to the surface of the yoke facing the body, which effectively superimposes the magnetic flux of the permanent magnet on the magnetic circuit of the electromagnet, and the coil height and magnetic pole spacing of the electromagnet, which are coefficients related to magnetomotive force and current density. The ratio of about 1.
The magnetic flux is effectively concentrated on the surface layer of the weak magnetic material by increasing the ratio from 5 to 3.5 times, and the end length of the electromagnet is changed by changing the sticking length of the permanent magnets installed on the outer and inner poles of the electromagnet. A magnetic levitation device for a weak magnetic material such as sinter or the like, which has a structure in which the magnetic flux is improved.