JP3331154B2 - Insulation plate for induction heating coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating coil for inductively heating a metal material to be heated, which is provided by radiant heat from the material to be heated, cooling water / steam, and oxidation called a scale generated on the surface of the material to be heated. The present invention relates to a heat insulating plate for shielding from an object or the like.

[0002]

2. Description of the Related Art An induction heating apparatus for induction heating a metal material applies an alternating current to an induction heating coil, generates an eddy current in the metal material by generated alternating magnetic flux, and heats the metal material by Joule heat. It is. Therefore,
The induction-heated metal material is heated to a high temperature near 1000 ° C.

On the other hand, since a high voltage of several hundreds to several thousand volts is applied to the induction heating coil, the coil surface is usually covered with an insulating material and, if necessary, cooled with cooling water or cold air. ing. The insulation coating of the induction heating coil is generally made of an F-class insulating material such as epoxy resin, so that about 150 ° C. is the maximum temperature that can withstand.
It cannot withstand receiving high-temperature radiant heat directly from the material to be heated.

FIG. 8 shows a heat insulating plate for an induction heating coil.
As shown in FIG. 1, a heat exchanger is provided which is composed of one or a plurality of tubes 81 made of a non-magnetic metal and arranged on the same plane or substantially the same plane and through which a cooling fluid can circulate. And any two of the tubes 81
As shown in FIG. 9, an electrode protection device for an electromagnetic induction device in which the tube or its tube element is electrically connected only at one place (JP-A-1-313882). In an induction heating apparatus for heating a thin plate-shaped material to be heated 91 by passing it through a heating coil 93 provided with a lining material 92 inside, the lining material 92 is fixed to the heating coil 93 and has good electric insulation. One member 94 and at least two kinds of second members 95 provided inside the first member 94 and having heat resistance and abrasion resistance, and the second member 95 is a collection of small pieces 95a. Induction heating coil device composed of a body
No. 155193), as shown in FIG. 10, for induction heating, a high temperature resistant woven fabric 103 and a high temperature resistant insulating member 104 are mounted on top of a cover 102 molded with cement to cover the induction heating coil 101. In the heat insulating material of the coil, the upper portion of the high-temperature resistant fabric 103, or between the high-temperature resistant fabric 103 and the high-temperature insulating member 104 and between the high-temperature insulating member 104 and the cover 102, 1.0 to 3.0 mm or 0.1 to 3.0 mm of the high refractory paint 105 containing 90% or more of alumina and silicon.
As shown in FIG. 11, a heat insulating material for an induction heating oscillation coil coated with 1 to 1.0 mm (Japanese Patent Application Laid-Open No. 5-335068), an inductor is attached to a magnetic pole opposed to the annular iron core with a gap therebetween, and the inductor is attached to the inductor. An electromagnetic induction heating device that energizes the annular iron core by applying an alternating current and that conveys a plate-shaped material to be heated and heats a side portion of the material to be heated that passes through the gap by electromagnetic induction. In a heat insulating member that thermally, chemically and mechanically protects the magnetic pole and the inductor from the material to be heated, the woven fabric 111 of silicon carbide fibers is laminated and the woven fabric 112 is also laminated in the laminating direction of the woven fabric 111. A heat insulating member (Japanese Patent Application Laid-Open No. H8-25565) has been proposed in which a formed three-dimensional fabric is impregnated with a slurry in which a polycarbosilane denaturing solution and silicon carbide powder are blended, and heated and pressed to form a predetermined shape. That.

[0005]

Problems to be Solved by the Invention
No. 882 discloses an electrode protection device for an electromagnetic induction device,
Electromagnetic vibration due to the electromagnetic force of an alternating magnetic field generated by passing an alternating current, impact force when the material to be heated collides with the induction heating device main body, or vibration indirectly received from peripheral mechanical devices Subject to mechanical stress on pipes. In addition, an electric spark is generated between the copper tube and another metal material due to a back electromotive force generated in the copper tube due to the influence of the alternating magnetic flux, and electric corrosion occurs. Furthermore, water vapor invades from the outside and corrodes the copper tube. JP-A-1-31388
In the electrode protection device disclosed in Japanese Unexamined Patent Publication No. 2 (1995) -2000, these factors overlap, and cracks and pinholes in the copper tube occur, or cracks occur in the hose connected to the copper tube, leading to accidents such as water leakage. There is a disadvantage that.

Further, the heat insulating member of the induction heating coil device disclosed in Japanese Patent Application Laid-Open No. 2-155193 has only one layer of heat-insulating plate material, and is made of a material having excellent wear resistance. As a heat insulating material having abrasion resistance, there is a solid material of ceramics. However, the thermal conductivity is 2 to 10 times larger than that of a woven cloth such as a ceramic cloth. The gap between the oscillation coil and the material to be heated also increases, the leakage magnetic flux that does not penetrate the material to be heated by part of the AC magnetic field increases, and the power factor deteriorates and the heating efficiency decreases. Occurs. Also, Japanese Patent Application Laid-Open No.
The heat-insulating member disclosed in Japanese Patent No. 5193 discloses a heat-insulating member and an abrasion-resistant second member formed of an aggregate of small pieces in order to reduce the thermal stress of the second member. It is fixed with a bolt that penetrates. However, with induction heating devices,
Since the electromagnetic vibration is large, usually a metal bolt which is hard to break is used. However, if the bolt is fixed with a bolt penetrating in the thickness direction of the second member, the radiant heat from the material to be heated passes through the bolt to the back surface of the second member. Since the number of bolts for fixing increases as the number of small pieces is increased by conduction, the number of bolts for fixing increases, and the heat insulation of the entire second member is reduced. The size of the piece cannot be reduced to about 150 mm × 150 mm or less, and cracks cannot be avoided due to thermal stress. Further, since the heat insulating member has a large area of the small piece material, if the small piece material is damaged due to contact with the material to be heated, the area of the damaged portion becomes large, and the heat insulating property is extremely reduced. Immediate replacement is required.

Further, the heat insulating material disclosed in Japanese Patent Application Laid-Open No. Hei 5-335068 is coated with a high refractory paint in order to prevent the scale from penetrating into the high-temperature resistant fabric. There is a problem that it is problematic, easily peels off, and the effect is not long lasting.

Furthermore, the heat insulating member disclosed in Japanese Patent Application Laid-Open No. Hei 8-25565 can withstand high-temperature radiant heat from the material to be heated, but the heat insulating member is exposed to descaling water for removing scale of the material to be heated. Degradation such as peeling from the surface of the heat insulating material due to the adhesion of scale or the like may occur, and the heat insulating property may decrease, the temperature of the rear surface of the heat insulating member may increase, and the insulator of the oscillation coil may be damaged. It is necessary to replace the material or increase the thickness of the heat insulating material. When the thickness of the heat insulating material is increased, the gap between the oscillation coil and the material to be heated also increases, the leakage magnetic flux that does not penetrate the material to be heated by a part of the AC magnetic field increases, the power factor deteriorates, and the heating efficiency decreases. Causes a drop.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks of the prior art, and to provide a heating coil without bathing descaling water for removing scale of a material to be heated and without deteriorating heat insulation performance due to adhesion of scale. An object of the present invention is to provide a heat insulating plate for an induction heating coil that can reduce a gap between the heating member and a material to be heated.

[0010]

According to a first aspect of the present invention, there is provided a heat insulating plate for an induction heating coil for protecting an induction heating coil for induction heating a conveyed metal material to be heated from radiant heat of the material to be heated. A heat-resistant layer of a heat-resistant material having excellent heat resistance and waterproofness facing the material to be heated,
Insulation excellent in ceramic cloth as alumina or cloth alone and the ceramic board is laminated in contact with the heating coil, silica cloth alone or ceramic made from the cross-alone heat insulating layer and a laminate to a multilayer structure and without a heat
The layer is composed of an aggregate of small pieces and the heat-resistant layer is composed.
A through hole in each small piece of material parallel to the surface of the heat insulating plate.
A mandrel is fixed through the through hole.

As described above, the conveyed metal material to be heated is
The induction heating coil for induction heating uses the radiant heat of the material to be heated.
A non-water-cooled heat insulating plate that protects
Heat-resistant layer of heat-resistant material with excellent heat and waterproof properties, and for heating
Ceramic cloth with excellent heat insulation and contact with the coil
Laminated board laminated or alumina cloth
Simple substance, silica cloth simple substance or ceramic cloth simple substance
And a heat insulating layer made of
And descaling water for scale removal of the material to be heated
Heat and water resistant to immersion and scaling
Since it is a heat-resistant layer of a heat-resistant material with excellent heat resistance, the heating coil
Laminated ceramic cloth and ceramic board
Or alumina cloth, silica cloth
Of insulation layer consisting of body or ceramic cloth alone
Deterioration due to adhesion of cooling water and scale
The replacement cycle can be extended, and the thickness of the heat insulating plate can be reduced to 1
/ 2 or less, between the heating coil and the material to be heated.
The gap can be reduced and the heating efficiency can be improved
You .

[0012] The heat-resistant layer facing the material to be heated may be a small piece material.
The thermal expansion is absorbed by the
Generation of cracks due to thermal stress can be suppressed.

Further, heat insulation is provided for each of the small pieces constituting the heat-resistant layer.
Drill a through hole parallel to the surface of the plate and pass a mandrel through the through hole
To secure the bolts per conventional small piece.
In the present invention, one mandrel was required.
And at least one set of bolts is required.
One piece can be fixed. Therefore, in the present invention
Is to reduce the area of small pieces per piece and
Even if the number of splits is increased, the number of bolts
Whilst suppress heat amount transmitted to the heat insulating plate back surface via bolts
Can be controlled. Also, in the present invention,
Since the area of the small piece material can be reduced, the material to be heated and the heat insulating plate
Even if the small piece material is damaged due to contact with
It is small and does not greatly reduce heat insulation.
Simple repairs such as application of heat-resistant concrete
Can respond.

According to a second aspect of the present invention, a heat insulating plate for an induction heating coil is a non-water-cooled heat insulating plate for protecting an induction heating coil for induction heating a material to be conveyed from radiant heat of the material to be heated. Dividing the heat insulating plate into a plurality of small pieces, and piercing a through hole in each of the divided small pieces in parallel with the surface of the heat insulating plate,
A mandrel is fixed through the through hole. In this way, by fixing the mandrel to the through-hole perforated in parallel with the surface of the heat insulating plate through each mandrel, at least one set of bolts is required for each mandrel. One piece can be fixed. Therefore, in the present invention,
Even if the area of each small piece is reduced to increase the number of divided small pieces, the number of bolts relative to the number of small pieces is reduced, and the amount of heat transmitted to the back surface of the heat insulating plate via the bolts is suppressed. be able to.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the heating of a material to be heated by an induction heating device, as shown in FIG. 7, if the air gap (gap) between the heating coil and the material to be heated increases, the heating efficiency decreases. It is advisable to minimize the distance between the heating coil and the material to be heated. The heat insulating plate of the induction heating coil of the present invention is such that the rear surface temperature of the heat insulating plate is 150 ° C. or less even for radiant heat of the material to be heated at 1000 ° C.
It has sufficient heat insulation to protect the heating coil, and
The thickness of the heat insulating plate is made as thin as possible.

As shown in FIG. 1, the heat-insulating plate of the coil for induction heating according to the first aspect of the present invention comprises a heat-resistant layer 1 made of a heat-resistant material having excellent heat resistance and waterproofness, which faces a material to be heated (not shown).
And a heat-insulating layer 2 made of a laminated ceramic cloth and a ceramic board having excellent heat insulating properties, which contact a heating coil (not shown), or a heat insulating layer 2 made of alumina cloth alone, silica cloth alone or ceramic cloth alone. 1 and a heat insulating layer 2. Further, the heat insulating layer of the induction heating coil according to the first aspect of the present invention has the heat resistant layer 1 composed of a large number of small pieces 11 as shown in FIG. Note that an insulating layer 12 is provided between the heat insulating layer 2 that is in contact with the heating coil and a heating coil (not shown).
Can also be laminated.

A number of small pieces 11 constituting the heat-resistant layer 1
As shown in FIG. 3, for example, 10 mm long, 10 mm wide,
A through-hole 13 parallel to the surface of the heat insulating plate is pierced in each small piece material 11 having a length of 30 mm, and a mandrel 14 made of tungsten, Al-Cr alloy or the like having excellent corrosion resistance and heat resistance is passed through the through-hole 13, A large number of small pieces 11 are fixed to the heat insulating layer 2 by the fixing pins 15.
Fixed to. Thus, the conventional Japanese Patent Laid-Open No. 2-1551
No. 93 (150 mm × 150 mm)
mm), the area of the small piece material 11 can be reduced to 1/75, the generation of cracks due to thermal stress is suppressed, and even when the small piece material 11 is damaged, heat insulation can be secured by simple repair. .

The heat-resistant material used for the heat-resistant layer 1 according to the present invention, which is excellent in heat resistance and waterproofness, has a heat-resistant temperature of at least 7
It is a material having a water resistance of 20 ° C. or higher, and specific examples thereof include aluminum titanate, high alumina, clay, zirconia, mullite, cordierite and the like. In the case of a material having a heat-resistant temperature of less than 720 ° C., when the induction heating device is used for hot rolling of steel, the material to be heated is rolled at a temperature not lower than the A ₁ transformation point of steel. Deteriorates, and induces deterioration of the heat insulating layer, thereby damaging the insulator of the coil.

Aluminum titanate, which is a particularly preferable material for the heat-resistant layer 1 in the present invention, has a coefficient of thermal expansion of 0.08% (1
000 ° C.), which is considerably smaller than the thermal expansion coefficient of 0.81% (1000 ° C.) of alumina ceramic which is a general heat insulating material, so that thermal stress is hardly generated. In the hot rolling, a material to be heated at about 1000 ° C. is sequentially rolled for a predetermined time of about 1 to 2 minutes per coil, and the induction heating device is cooled by taking descaling water or the like during the rolling. Therefore, a heat cycle test was performed to evaluate the heat resistance. In the heat cycle test, the test piece was heated in a furnace heated to 1000 ° C for 5 minutes, and then rapidly cooled in water at about 20 ° C. As a result, the test piece of alumina ceramic cracked three times, whereas the test piece of aluminum titanate had 100 cracks.
No cracks were generated and the strength was not degraded even after repeated times.

Examples of the material having excellent heat insulating properties used for the heat insulating layer of the heat insulating plate of the induction heating coil according to the present invention include a laminate of a ceramic cloth and a ceramic board, an alumina cloth, a silica cloth, and a single ceramic cloth. Can be.

In the present invention, the mandrel used for fixing each small piece of the heat-resistant layer facing the material to be heated includes tungsten, molybdenum, platinum, and Cr-, which are excellent in corrosion resistance and heat resistance.
Al alloy, Ni-Cr alloy, Fe-Cr alloy, FeCr
An Al alloy or the like can be used.

[0022]

As shown in FIGS. 4 and 5, a heat insulating plate 41 is provided to reduce the distance between an induction heating coil (not shown) and a material to be heated as much as possible to improve the heating efficiency.
And a heat insulating layer 42 having a thickness of 10 mm and having a thickness of 25 mm or less, and a heat insulating layer 42 laminated with a ceramic cloth and a ceramic board as the heat insulating layer 42 so that the temperature of the back surface of the heat insulating plate is also 150 ° C. or less even for radiant heat of the material to be heated at about 1000 ° C. Was used.
As the heat-resistant layer 43 facing the material to be heated, the heat-resistant layer 43 has a length of 10 mm.
In the longitudinal direction of a small piece of aluminum titanate 44 mm, 10 mm in width and 30 mm in length, a through-hole 45 parallel to the surface of the heat insulating plate is formed in the longitudinal direction, and Cr-Al having excellent corrosion resistance and heat resistance is provided.
It was fixed to the entire surface of the heat insulating layer 42 through an alloy mandrel.
In addition, in order to support the heat insulating layer 42 and the heat resistant layer 43 on the main body of the induction heating device, the heat insulating layer 42 has a thickness of 5 mm on the heating coil side.
Of the heat insulating layer 42 and the heat resistant layer 4
3 was held.

As shown in FIG. 6, the insulating plate 41 of the present invention has a thickness of 25 mm according to the present invention and is attached to the lid of an electric furnace 62 kept at the same temperature as the material to be heated at 1000.degree. When the thermocouple 63 was installed on the back of the epoxy resin plate 46 of the heat insulating plate 41 and the temperature of the rear surface of the heat insulating plate 41 was measured, the temperature was 150 ° C. or less. From this result, it was confirmed that the heat insulating plate 41 of the present invention can protect the heating coil of the induction heating device installed on the back surface of the heat insulating plate from the radiant heat of the material to be heated.

The heat insulating plate of the present invention was applied to an actual apparatus for induction heating a material to be heated at 900 ° C. or higher, and the back surface temperature of the heat insulating plate was 150 ° C. or lower.

[0025]

According to the first aspect of the present invention, the heat insulating plate of the coil for induction heating comprises a heat-resistant layer of a heat-resistant material facing the material to be heated and having excellent heat resistance and waterproofness, and a heat insulating layer for contacting the heating coil. The overall thickness is 25mm due to a multilayer structure in which a ceramic cloth and a ceramic board excellent in lamination are laminated or a heat insulating layer composed of alumina cloth alone, silica cloth alone or ceramic cloth alone is laminated.
The thickness can be reduced to below, and the heating efficiency can be improved.
Thermal deterioration of the coil due to the influence of radiant heat from the material to be heated at 00 ° C. can be prevented. Further, it is possible to prevent deterioration of the heat insulating plate due to descaling water or scale.

In the heat insulating plate of the induction heating coil according to the first aspect of the present invention, the heat-resistant layer facing the material to be heated is formed by collecting small pieces.
Insulation made by uniting and perforating small pieces of heat-resistant layer
By fixing the mandrel through a mandrel in a through hole parallel to the surface of the plate
Therefore, thermal expansion is absorbed and cracks occur due to thermal stress.
The production can be suppressed, and the conventional small piece material
Although one or more bolts were required, the present invention
At least one bolt is required for one bolt, and one mandrel
A large number of small pieces can be fixed. Therefore, the book
In the invention, the area of the small piece material per piece is reduced to reduce the small piece.
Even if the number of divisions of the material is increased, the bolt
Heat is transmitted to the back side of the insulation board via bolts
The amount can be suppressed. In the present invention, one
Since the area of the small piece of material can be reduced, it is
Even if small pieces are damaged due to contact with a hot plate, etc.
Small area, no significant decrease in heat insulation, replacement of small pieces
Even without the complement Osamu, simple such as coating of heat-resistant concrete
It can be dealt with by repair.

According to a second aspect of the present invention, in the heat insulating plate for an induction heating coil, the heat insulating plate is divided into a plurality of small pieces, and a mandrel is passed through a through hole formed in each small piece in parallel with the surface of the heat insulating plate. By fixing, at least one bolt is required for one mandrel, and one mandrel can fix many small pieces. Therefore, in the present invention, even if the area of the small piece material per piece is reduced and the number of divided small piece materials is increased, the number of bolts with respect to the number of small piece materials is reduced, and the back surface of the heat insulating plate is connected via the bolts. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat insulating plate according to claim 1 of the present invention.

FIG. 2 is a perspective view of the heat insulating plate according to claim 1 of the present invention.

FIG. 3 is an explanatory view of a method of fixing each small piece constituting the heat-resistant layer of the heat insulating plate according to claim 1 of the present invention, and FIG. 3 (a) is a perspective view showing a state where a mandrel is passed through a through hole of the small piece; (B) is a side view in the state where each small piece material was fixed to the heat insulating layer.

FIG. 4 is a schematic side view of the heat insulating plate according to the first embodiment of the present invention.

FIG. 5 is a perspective view of a small piece constituting a heat-resistant layer of the heat insulating plate according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of a confirmation test of the heat insulating performance of the heat insulating plate according to the first embodiment of the present invention.

FIG. 7 is a graph showing a relationship between an air gap including a heat insulating plate thickness and heating efficiency.

FIG. 8 is a schematic view of an induction electrode provided with a protection device disclosed in Japanese Patent Application Laid-Open No. 1-313882.

FIGS. 9A and 9B show an induction heating device disclosed in Japanese Patent Application Laid-Open No. 2-155193, wherein FIG. 9A is a front view partially showing a cross section, and FIG. 9B is an AA arrow of FIG. (C) is a view taken in the direction of arrows B-B in FIG.

FIG. 10 is a perspective view schematically showing a heat insulating material disclosed in JP-A-5-335068.

FIG. 11 is a perspective view of a heat insulating member disclosed in JP-A-8-25565.

[Explanation of symbols]

 1, 43 heat-resistant layer 2, 42 heat-insulating layer 11, 44, 95a small piece material 12 insulating layer 13, 45 through hole 14 mandrel 15 fixing pin 41 heat-insulating plate 46 epoxy resin plate 61, 93, 101 heating coil 62 electric furnace 63 thermoelectric Pair 81 Tube 91 Heated material 92 Lining material 94 First member 95 Second member 102 Cover 103 High temperature resistant fabric 104 High temperature resistant insulating member 105 High fire resistant paint 111, 112 Woven cloth

Continued on the front page (72) Inventor Hirotoshi Michimoto 1850 Minato, Wakayama-shi, Wakayama Sumitomo Metal Industries, Ltd. Inside Wakayama Works (72) Inventor Kenji Imae 1-7-12 Tomita-cho, Takatsuki-shi, Osaka Imae Kogyo (72) Inventor Sadao Kawanishi 1-7-12 Tomita-cho, Takatsuki-shi, Osaka Imae Industry Co., Ltd.Examiner Takayuki Sugiura (56) References JP-A-2-155193 (JP, A) Hei 5-25690 (JP, U) Japanese Utility Model Showa 62-171186 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 6/10 H05B 6/36

Claims (2)

(57) [Claims] 1. An induction heating method for a conveyed metal material to be heated.
The induction heating coil from the radiant heat of the material to be heated
Non-water-cooled heat-insulating plate with heat resistance facing the material to be heated
And a heat-resistant layer of heat-resistant material
Ceramic cloth and ceramic with excellent heat insulation
Or laminated alumina board
Body, silica cloth or ceramic cloth
Heat insulation layer to form a multi-layer structure
Together constitute a collection of wood, perforated surface parallel to the through-hole of the heat insulating plate each piece material constituting the heat-resistant layer, induction heating coil you characterized in that fixed through the mandrel into the through hole Insulation board. 2. A non-water-cooled heat insulating plate for protecting an induction heating coil for induction heating of a conveyed metal material to be heated from radiant heat of the material to be heated, the heat insulating plate is divided into a plurality of small pieces. A heat insulating plate for an induction heating coil, characterized in that a through hole is formed in each of the divided small pieces in parallel with the surface of the heat insulating plate, and a mandrel is fixed through the through hole.