AU2137199A

AU2137199A - Induction heating apparatus

Info

Publication number: AU2137199A
Application number: AU21371/99A
Authority: AU
Inventors: Tetsuji Doizaki; Koji Dojo; Susumu Ishihara; Norio Kudo; Manabu Sonobe; Yasumichi Wakamatsu
Original assignee: Toshiba Mitsubishi Electric Industrial Systems Corp; Kitashiba Electric Co Ltd
Current assignee: Toshiba Mitsubishi Electric Industrial Systems Corp; Kitashiba Electric Co Ltd
Priority date: 1998-03-24
Filing date: 1999-03-23
Publication date: 1999-10-28
Anticipated expiration: 2019-03-23
Also published as: ID22276A; TW409486B; CN1236288A; KR100296227B1; AU717883B2; KR19990078162A; CN1127885C

Description

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): KABUSHIKI KAISHA TOSHIBA KITASHIBA ELECTRIC CO.LTD.

Invention Title: INDUCTION HEATING APPARATUS.

The following statement is a full description of this invention, including the best method of performing it known to me/us: :i 1 ii-~i TITLE OF THE INVENTION INDUCTION HEATING APPARATUS BACKGROUND OF THE INVENTION The present invention relates to an induction heating apparatus for heating a heating target plate conveyed on a steel hot rolling line midway along the line.

Generally, in a steel hot rolling line, a heating target plate (slab) pre-heated to a high temperature by 1. 0 a heating furnace is continuously, sequentially .".supplied to a rolling mill to form a thin plate. When a thin plate is formed by rolling with such a steel hot rolling line, as the distance from the heating furnace to the rolling mill is long, the temperature of the plate undesirably drops before the heating target plate *...reaches the rolling mill. For this reason, the heating target plate is heated midway along the line to increase its entire temperature, and thereafter the two end portions of the heating target plate are locally heated by edge heaters to set the entire heating target plate to an almost uniform temperature. Then, the heating target plate is supplied to the rolling mill to form a thin plate.

As an induction heating apparatus for increasing the temperature of the heating target plate by entirely heating it midway along the line in this manner, one shown in FIG. 1 is available. According to this 2 apparatus, a water-cooling steel pipe is wound to form a solenoid coil 2 horizontally elongated in the direction of plate width of a heating target plate i.

A refractory material layer 4 made of castable cement 3 is formed on the inner side of the solenoid coil 2 to form a cylindrical heating path 5. The heating target plate 1 is passed through the heating path 5 to entirely heat it by induction heating.

In this case, the solenoid coil 2 is protected by various types of insulating materials for the purpose of electrical insulation. Such an insulating material has a heat resistant temperature of about 180 Since radiation heat from the induction-heated heating target plate 1 reaches a high temperature of 1,0009C to 1,100°C, "15 the refractory material layer 4 is formed on the ~surface of the solenoid coil 2 to protect the coil insulating material. Electrically conductive oxide scales are formed on the surface of the heating target plate 1 heated to a high temperature. When the oxide scales are separated and attracted by the magnetic force, insulation of the coil degrades. The refractory material layer 4 prevents the oxide scales from entering the coil 2.

The smaller the gap between the heating target plate 1 and solenoid coil 2, the higher the heating efficiency. However, to achieve heat insulation and entrance prevention of the oxide scales, a conventional 3 induction heating apparatus has a thick refractory material layer 4, and its heating efficiency decreases accordingly. Since the refractory material layer 4 is formed into a cylindrical shape horizontally elongated in the direction of plate width of the heating target plate i, it has a long horizontal width. The outer side of the cylindrical refractory material layer 4 is surrounded by the solenoid coil 2. Therefore, the refractory material layer 4 is subjected to the 10 high-temperature radiation heat to form a crack 6 easily. When the crack 6 is formed in this manner, the *refractory material may be separated, or oxide scales .i may enter the solenoid coil 2 through a portion where :the refractory material has separated to degrade insulation of the coil 2.

The refractory material layer 4 is made of castable cement and is soft accordingly. The heating target plate 1 that passes through the heating path is not flat but may be waved or have an arcuated end portion. While the heating target plate 1 passes, it may come into contact with the surface of the refractory material layer 4 and be fractured. When the refractory material layer 4 is fractured, the insulating material of the solenoid coil 2 is fractured or burned by the radiation heat or the entering oxide scales, leading to short-circuiting of the coil 2.

Then, the operation must be stopped to repair or 4 exchange the refractory material layer 4, so that the operation must be stopped over a long period of time.

Concerning an upper refractory material, the separated refractory material drops onto the heating target plate 1 to degrade the rolling quality.

The conventional induction heating apparatus is integrally incorporated with an RF power supply unit having a capacitor for energizing a heater and a water supply mechanism. This integral structure is fixed to the line.

Of the induction heating apparatus, a heater •portion influenced by the radiation heat from the heating target plate heated to a high temperature tends to be damaged most easily. Maintenance must be S 15 performed as required to inspect the heater portion or to replace its components.

In the conventional induction heating apparatus, since the heater and the RF power supply are fixed to S. 55 e the line, the line must be stopped to disassemble or to 5* inspect the apparatus. A plurality of induction heating apparatuses are installed among convey rolls.

The distance between adjacent induction heating apparatuses is as small as 400 mm or less. The operator must enter this small space to perform maintenance, which is cumbersome and provides a poor workability.

BRIEF SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and has as its object to provide an induction heating apparatus in which a refractory material layer is water-cooled to prevent cracking and entrance of oxide scales so as to prevent degradation in insulation of the solenoid coil, and the refractory material layer is formed thin to improve the heating efficiency.

10 It is another object of the present invention to provide an induction heating apparatus in which a heating target plate passing through the heating path ad is prevented from coming into contact with the refractory material layer to be damaged, so that 15 operation can be performed stably over a long period of time.

It is still another object of the present invention to provide an induction heating apparatus the S. .5 .maintenance of which can be performed by conveying the heater main body to a separate place.

In order to achieve these objects, of the first aspect of the present invention, there is provided an induction heating apparatus comprising: a solenoid coil for heating a heating target; and a refractory material layer formed on an inner side of the solenoid coil to form a medium path where cooling water is to be passed.

6 Of the second aspect of the present invention, there is provided an induction heating apparatus comprising: a solenoid coil for heating a heating target; and a refractory material layer formed on an inner side of the solenoid coil and formed by combining a plurality of blocks.

Of the third aspect of the present invention, there is provided an induction heating apparatus r000O S10 comprising: a solenoid coil for heating a heating target; S• a refractory material layer formed on an inner side of the solenoid coil; and skid beams formed to project toward the refractory 15 material layer along a convey direction of the heating target.

Of the fourth aspect of the present invention, there is provided an induction heating apparatus comprising: a truck movable on a rail placed in a direction substantially perpendicularly intersecting a convey direction of a heating target; a heater formed on the truck to heat the heating target; and a power supply formed on the heater to supply power to the heater.

Of the fifth aspect of the present invention, 7 there is provided an induction heating apparatus comprising: a heater formed on a first truck movable on a rail placed in a direction substantially perpendicularly intersecting a convey direction of a heating target, to heat the heating target; and a power supply formed on a second truck movable on the rail to supply power to the heater, wherein the first truck is separatably connected to the second truck such that the power supply is located on the heater.

Of the sixth aspect of the present invention, there is provided an induction heating apparatus S• comprising: heaters respectively formed on first trucks movable on rails placed in a direction substantially perpendicularly intersecting a convey direction of a heating target, to heat the heating target; and %.too "C4" a power supply formed on a second truck movable on the rails to supply power to the heaters, wherein the first trucks are separatably connected to the second truck such that the power supply is located on the heaters.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is a sectional view showing a conventional induction heating apparatus; FIG. 2 is a sectional view of an induction heating 8 apparatus according to the first embodiment of the present invention; FIG. 3 is a plan view showing a flat block shown in FIG. 2; FIG. 4 is a perspective view showing an L-shaped arcuated corner block shown in FIG. 2; FIG. 5 is an enlarged sectional view of the flat block shown in FIG. 2; FIG. 6 is an enlarged sectional view of a flat block according to a modification of the present invention; FIG. 7 is a longitudinal sectional front view of an induction heating apparatus according to the second 4R iembodiment of the present invention; FIG. 8 is an enlarged, longitudinal sectional side view of the upper portion of the induction heating apparatus shown in FIG. 7; :FIG. 9 is an enlarged, longitudinal sectional side view of the heat resistant plate shown in FIG. 7; FIG. 10 is a cross-sectional plan view of the .i refractory material layer of the heat resistant plate shown in FIG. 9; FIG. 11 is a perspective view showing an induction heating apparatus according to the third embodiment of the present invention; FIG. 12 is a front view of the induction heating apparatus according to the third embodiment; 9 FIG. 13 is a perspective view showing an induction heating apparatus according to a modification of the third embodiment of the present invention; FIG. 14 is a front view of the induction heating apparatus shown in FIG. 13; FIG. 15 is a side view of the induction heating apparatus shown in FIG. 13; FIG. 16 shows a state wherein the axle of the rear wheels of a heater truck is supported by an axle lifting guide; FIG. 17 shows a state wherein the heater truck is Sseparated; FIG. 18 is a perspective view showing a state wherein a heater main body is hoisted by a crane; and S 15 FIG. 19 shows a state wherein two induction heating apparatuses are retreated from the line.

a DETAILED DESCRIPTION OF THE INVENTION <First Embodiment> The first embodiment of the present invention will be described in detail with reference to FIGS. 2 to a In this induction heating apparatus, as shown in FIG. 2, a water-cooling steel pipe 7 is wound in a solenoid coil 2 horizontally elongated in the direction of plate width of a heating target plate i. A refractory material layer 4 mounted with insulating support plates 8 is formed on the inner side of the solenoid coil 2 to form a cylindrical heating path 5. The heating target 10 plate 1 is passed through the heating path 5 to entirely heat it by induction heating.

The refractory material layer 4 is formed into a cylindrical shape by combining a plurality of flat blocks 4a and L-shaped arcuated corner blocks 4b both made of castable cement 3. As shown in FIGS. 3 and each flat block 4a is integrally formed by spirally winding a stainless steel pipe 11 serving as a cooling water path and casting the castable cement 3 around it.

As shown in FIG. 4, each corner block 4b is integrally molded by placing a stainless steel pipe 11 serving as a cooling water path in a winding manner and casting S"the castable cement 3 around it. As the stainless steel pipe 11, one having a thickness smaller than the depth of penetration of the current is employed.

In order to hold the stainless steel pipe 11 placed spirally or in a winding manner, studs 12 are formed to extend from the water-cooling pipe 11 at predetermined intervals, as shown in FIG. 5. The studs 20 12 are made to extend through the insulating support plate 8 placed on the solenoid coil 2 and formed of a glass-cloth laminate, and are fixed by stainless steel nuts 14. The L-shaped arcuated corner blocks 4b constituting the right and left inner wall sides of the cylindrical heating path 5 are attached such that their outer sides are integrally surrounded by the U-shaped insulating support plates 8, as shown in FIG. 2.

11 As shown in FIG. 2, steps 16 are formed on the two side end faces of each of the flat blocks 4a and L-shaped arcuated corner blocks 4b. Adjacent blocks 4a and 4b are fitted with each other, and a gap between them is filled with mortar 17, as shown in FIG. 5, to integrally bond them.

The induction heating apparatus having the above structure continuously heats the entire heating target plate 1 by passing the traveling heating target plate 1 in the cylindrical heating path 5 and supplying an RF current to the solenoid coil 2. In this case, when 0*e~ee .cooling water is supplied to the water-cooling pipe 11 buried in the refractory material layer 4 opposing the heating target plate i, the refractory material layer 4 is cooled from the inner portion. A temperature increase can be suppressed low even if the refractory 4 material layer 4 is heated by radiation heat of the i'o' heating target plate 1 heated to about 1,1009C.

0000 The mortar 17 fills the gaps between the fitted steps 16 of the flat blocks 4a and L-shaped arcuated ".corner blocks 4b constituting the refractory material layer 4, to close the gaps, so that entrance of radiation heat through the gaps is prevented. Since the refractory material layer 4 has a divisional structure constituted by the blocks 4a and 4b, thermal stress is absorbed by the fitted portions of the steps 16 to prevent cracking. Since the L-shaped arcuated 12 corner blocks 4b constituting the right and left inner wall sides of the heating path 5 are attached such that their outer sides are surrounded by the U-shaped insulating support plates 8, cracking in the corner portions can be prevented.

The water-cooling pipe 11 serving as the water path is made of a nonmagnetic material and has a thickness smaller than the depth of penetration of the current. Even if the pipe 11 is heated by a magnetic flux, its temperature increase is small, and the temperature of the coil can be suppressed to about 009C.

*As a result, thermal degradation and cracking in the *refractory material layer 4 are prevented to maintain the hardness and strength, and entrance of oxide scales 15 and degradation in insulation of the solenoid coil 2 ~can be prevented over a long period of time.

e FIG. 6 shows a modification of the present invention. A stainless steel pipe 11 is placed spirally or in a winding manner. Studs 12 are formed to extend from the water-cooling pipe 11 at predetermined intervals. The studs 12 are made to extend e* through insulating support plates 8 placed on a solenoid coil 2 and formed of a glass-cloth laminate, and are fixed with stainless steel nuts 14. Portions of the pipe 11 where no studs 12 extend are bound together with a glass fiber 18. The pipe 11 is entirely held in this manner.

13 A projection 19 and recess 20 are formed on the two side end faces of each of flat blocks 4a and L-shaped arcuated corner blocks 4b constituting a refractory material layer 4. The projection 19 and recess 20 of adjacent blocks 4a and 4b are fitted with each other, and a gap between them is filled with mortar 17, thereby integrally bonding them. The fitting structure of the adjacent blocks 4a and 4b is not limited to this, but may be another combination s10 structure such as a combination of inclined surfaces or combination of a recessed curved portion and a projecting curved portion.

As described above, with the induction heating apparatus according to the present invention, the 15 cylindrical refractory material layer is formed by combining a plurality of flat blocks and arcuated corner blocks. A cooling pipe constituted by a water-cooling pipe made of a nonmagnetic material is *..placed in each block to cool the block from the inner portion. Heating by radiation heat from the heating target plate is suppressed low to greatly prolong the service life of the refractory material layer.

Dielectric breakdown or short-circuiting of the solenoid coil can be prevented over a long period of time to allow stable operation. Since the cylindrical refractory material layer is formed by combining the plurality of blocks, it can be formed easily. If the 14 refractory material layer is partly damaged, only a damaged block can be exchanged, facilitating the repair operation.

The water-cooling pipes each made of the nonmagnetic material are buried in the respective blocks constituting the cylindrical refractory material layer to form the independent water path. The insulating support plates surround the outer sides of the blocks and are connected to the stainless steel 10 pipes, thereby holding the blocks. Even if the water-cooling pipes are heated by a magnetic flux, their temperature increase is small. Since the .i Sa. water-cooling pipes are reliably held by the insulating support plates that surround the outer sides of the 15 blocks, dropping of the refractory material can be prevented, and cracking in the corner portions can be prevented.

<Second Embodiment> The second embodiment of the present invention will be described with reference to FIGS. 7 to 10. A refractory material layer 103 is formed on the inner side of a solenoid coil 101, formed by. winding a water-cooling copper pipe into an elongated circular shape, to form a heating path 105 where a heating target 102 passes inside the refractory material layer 103. A heat resistant plate 106 has a composite structure. As shown in FIG. 9, the heat resistant plate 106 is constituted by the refractory material layer 103 buried with a water-cooling pipe 104 made of a nonmagnetic metal such as stainless steel, and an insulating support plate 108 made of a glass epoxy laminate or the like on the solenoid coil 101 side of the refractory material layer 103. Furthermore, skid beams 117, each formed of a nonmagnetic metal rod of stainless steel or the like into a rail shape, are mounted on the heating path 105 side of the refractory material layer 103 buried with the water-cooling pipe 104.

As shown in FIG. 7, the heat resistant plates 106 are mounted on the upper and lower surfaces of the heating path 105 having an elongated circular shape.

U-shaped heat resistant corner plates 107 are mounted on the two sides of the arcuated heating path 105 to form the cylindrical refractory material layer 103.

Similar to the heat resistant plate 106, each U-shaped a heat resistant corner plate 107 has a composite structure of the refractory material layer 103 and insulating support plate 108, except that no skid beams 117 are formed on it.

The arrangement of the heat resistant plate 106 will be described in detail. As shown in FIG. 10, the water-cooling pipe 104 made of a nonmagnetic metal such as stainless steel is placed in a winding manner to form a water path continuous in one direction. The 16 skid beams 117 made of a nonmagnetic metal such as stainless steel are bonded to one surface of the water-cooling pipe 104 along the convey direction of the heating target 102. Castable cement is cast by using a molding die. The resultant structure is thus formed into a plate such that the skid beams 117 project from the surface of the refractory material layer 103, as shown in FIG. 9.

On a side of the water-cooling pipe 104 opposite 10 to the skid beams 117, fixing stud bolts 119 are welded t at predetermined intervals, as shown in FIG. 9. Bolt insertion holes 120 are formed in the insulating support plate 108 to correspond to the fixing stud bolts 119. The fixing stud bolts 119 are inserted in 15 the bolt insertion holes 120 and integrally bonded through nuts 121. Attaching stud bolts 122 are bonded to the end portions of the insulating support plate 108.

The attaching stud bolts 122 are inserted in attaching holes 124 formed in stainless steel plates 114 and fixed with nuts 121, as shown in FIG. 8, to mount the heat resistant plate 106 on the inner side of the solenoid coil 101.

As shown in FIG. 7, iron cores 109 are mounted on the upper and lower portions of the outer circumference of the solenoid coil 101, wound into an elongated circular shape, in the direction of coil axis. As shown in FIG. 8, an outer casing plate 115 as a 17 combination of a water-cooling magnetic shield plate 112 and a stainless plate 114, that are bonded to each other, is mounted on each of the two sides of each iron core 109, on each of the inlet and outlet sides of the heating path 105. The water-cooling magnetic shield plate 112 is formed by flatly bonding a water-cooling copper pipe 111 formed of a square pipe on the outer circumference of a copper plate 110. The stainless steel plate 114 is formed by bonding a cooling pipe 113 to the outer side of the water-cooling magnetic shield plate 112.

In this induction heating apparatus, when an AC o current is supplied to the solenoid coil 101, the heating target 102 continuously traveling in the 15 heating path 105 is induction-heated to increase the temperature of the entire target. The refractory S" material layer 103 protects the solenoid coil 101 from radiation heat of the heating target 102 heated to a high temperature and cooled by the water-cooling pipe 104 buried in the refractory material layer 103.

The heating target 102 that passes through the heating path 105 may be waved or have an arcuated end portion. When this arcuated portion passes through the heating path 105, it travels while abutting against the skid beams 117 projecting from the surface of the refractory material layer 103, so that it can be prevented from coming into contact with the refractory 18 material layer 103. Therefore, damage to the refractory material layer 103 is prevented, and operation need not be stopped to repair or exchange the refractory material layer 103.

Even when the oxide scales of the heating target 102 are attracted by the magnetic force of the solenoid coil 101 to penetrate the refractory material layer 103, or even when the refractory material layer 103 causes cracking due to heat shock and is separated to drop, 10 since the very hard insulating support plates 108 each 0* eee e formed of a glass fiber laminate are provided between the refractory material layer 103 and solenoid coil 101, the oxide scale cannot penetrate the refractory material layer 103, and dielectric breakdown of the 15 solenoid coil 101 can be prevented.

go 5 In the above description, a glass fiber laminate is used as the insulating support plate 108. However, eeoc any other material having a strength and insulation can 0O be used.

S..

As shown in FIG. 8, the outer casing plates 115 are mounted to surround the two end sides of the solenoid coil 101. The outer casing plate 115 forming a composite component of the stainless steel plate 114 and water-cooling magnetic shield plate 112 can magnetically shield the magnetic flux generated by the solenoid coil 101 with its water-cooling magnetic shield plate 112 so as not to leak to the outside. In 19 this case, the copper plate 110 has a small temperature increase and provides a good magnetic shield effect as it has a low resistivity and does not easily generate a magnetic flux. Since the copper plate 110 is cooled by the water-cooling copper pipe 111 attached to it, it can decrease a temperature increase.

The surface portion of the outer casing plate 115 subjected to radiation heat from the heating target 102 induction-heated to a high temperature is formed of the i stainless steel plate 114 having a good heat resistance, O is cooled from the outside by the cooling pipe 113, and eeoe• is in tight contact with the water-cooling magnetic shield plate 112 cooled with water so as to be cooled from inside, thus resulting in a small temperature increase. Namely, since the surface of the water-cooling magnetic shield plate 112 is shielded by the stainless steel plate 114 having a good heat resistance, it rarely receives radiation heat directly from the heating target 102, thus resulting in a small temperature increase. Even if the operation is performed continuously, no large thermal stress is applied to the water-cooling magnetic shield plate 112, and water leakage of the cooling water from the water-cooling copper pipe 111, which is caused by cracking, can be prevented.

As described above, with the induction heating apparatus according to the present invention, the 20 heating target passing through the heating path is prevented by the skid beams from coming into contact with the refractory material layer, so that operation can be performed stably over a long period of time.

Furthermore, the very hard insulating support plates are placed on the rear side of the refractory material layer 103. This supports the cooling pipe 113 and can prevent dielectric breakdown of the solenoid coil caused by entrance of oxide scales or the like.

10 <Third Embodiment> e The third embodiment of the present invention will be described in detail with reference to FIGS. 11 and 12. Referring to FIGS. 11 and 12, in an induction heating apparatus 201, a heater 203 and an RF power supply 216 having a capacitor 215, a control circuit, *and the like are integrally formed in a truck 202, as shown in FIG. 12. In the heater 203, a cylindrical heating path 213 is formed inside a solenoid coil 212 horizontally elongated in the direction of plate width of a heating target plate 206. Front wheels 220 and driving wheels 218 on the rear wheel side are provided to the bottom portion of the truck 202. The driving wheels 218 are connected to a motor 217 to be rotated by it.

Water-intake and water-discharge two cooling water pipes 214 are attached to the front surface of the induction heating apparatus 201 to extend in the 21 vertical direction, in order to water-cool the solenoid coil 212. The upper portions of the cooling water pipes 214 are guided to the upper surface of the RF power supply 216, and are guided, together with a busbar 225, by a cable bearer 226 from this portion.

A plurality of induction heating apparatuses 201 each having the above arrangement are installed along a rolling line where the heating target plate 206 is conveyed, as shown in FIG. 11, and a plurality of 10 convey rolls 207 are placed among the induction heating apparatuses 201. A plurality of rails 208a, 208b, 208c, *o ao 208d, and 208h are placed among the convey rolls u to 207 to perpendicularly intersect the rolling line, and a.e S. the trucks 202 of the induction heating apparatuses 201 are respectively set on them to be able to travel freely.

a The plurality of induction heating apparatuses 201 each having the above arrangement are installed along the rolling line. When the heating target plate 206 that has been conveyed on the convey rolls 207 passes through the cylindrical heating path 213, it is entirely induction-heated by the heater 203 formed of the solenoid coil 212 and is temperature-increased. In this manner, the temperature of the entire heating target plate 206 gradually increases while the heating target plate 206 sequentially passes through the plurality of induction heating apparatuses 201.

22 To perform maintenance, inspection or component exchange, of the induction heating apparatus 201, the driving wheels 218 attached to the truck 202 are rotated by the motor 217 to make the induction heating apparatus 201 travel on the rails 208a, 208b, 208h, so that the induction heating apparatus 201 is retreated from the rolling line. In this manner, since inspection and maintenance of the induction heating apparatus 201 can be performed see& 10 after the induction heating apparatus 201 is retreated S. S.

C Sfrom the rolling line, the line during operation need :not be stopped. Since only the induction heating apparatus 201 that needs maintenance is retreated, sufficiently large spaces can be ensured on its two sides, and the operation can be performed easily. Once *".°:exchange or inspection is ended, the driving wheels 218 are rotated to move the truck 202 forward to return to the rolling line.

o FIGS. 13 to 19 show a modification of the third embodiment of the present invention. As shown in FIGS. 13 and 14, an induction heating apparatus 201 is formed by a combination of L-shaped heater trucks 202A and 202B, rectangular parallelepiped heater main bodies 203A and 203B placed on the heater trucks 202A and 202B, and an inverted L-shaped power supply truck 204 detachably connected to overlap the heater main bodies 203A and 203B simultaneously.

23 A plurality of induction heating apparatuses 201 each formed in this manner are installed along a rolling line where a heating target plate 206 is conveyed, and a plurality of convey rolls 207 are placed among them. A plurality of rails 208a, 208b, 208h are placed among the convey rolls 207 to perpendicularly intersect the rolling line. The L-shaped heater truck 202A is set on the rails 208a and 208b, and another L-shaped heater truck 202B is set S 10 on the rails 208c and 208d that are adjacent to the rails 208a and 208b through the convey roll 207.

As shown in FIG. 14, in each of the heater main bodies 203A and 203B placed on the L-shaped heater trucks 202A and 202B, a cylindrical heating path 213 is S 15 formed inside a solenoid coil 212 horizontally elongated in the direction of plate width of the 9 heating target plate 206. As shown in FIG. 18, rails 211a and 211b are formed on the upper surfaces of the heater main bodies 203A and 203B, respectively.

Water-intake and water-discharge cooling water pipes 214a and 214b are attached to the front surface of the induction heating apparatus 201 to extend in the vertical direction, in order to water-cool the solenoid coil 212.

As shown in FIG. 14, front wheels 209a and rear wheels 209b are attached to the bottom portion of each of the L-shaped heater trucks 202A and 202B to be able 24 to travel on the rails 208a and 209b. Separate rails 211c and 211d are attached to the upper surface of the vertical portion of each of the L-shaped heater trucks 202A and 202B. When the heater main bodies 203A and 203B are placed on the L-shaped heater trucks 202A and 202B, they are combined to form a rectangular parallelepiped shape, and the rails 211a and 211c, and 211b and 211d on the upper surfaces of the heater main bodies 203A and 203B continue to extend linearly.

10 The power supply truck 204 is formed into an inverted L-shape, as shown in FIG. 14. An RF power supply 216 provided with a capacitor 215, a control circuit, and the like is formed in the horizontal portion of the inverted L-shaped portion. Driving 15 wheels 218 connected to a motor 217 are mounted to the lower side of the vertical portion of the inverted L-shaped portion so as to travel on the rails 208a and 208b. Front wheels 220 are mounted on the distal end of the bottom surface of the horizontal portion of the inverted L-shaped portion so as to travel on the rails 211a and 211b of the heater main bodies 203A and 203B and on the rails 211c and 211d of the heater trucks 202A and 202B.

As shown in FIG. 16, L-shaped axle lifting guides 221 extend from the lower portion of the front surface of the vertical portion of the power supply truck 204.

When the power supply truck 204 and the heater trucks 202A and 202B are connected to each other, axles 210 on the rear wheels 209b side of the heater trucks 202A and 202B are guided by the axle lifting guides 221 to float the rear wheels 209b above the rails 208a, 208b, 208c, 208d, As shown in FIG. 13, four cooling water pipes 214b are mounted to extend from the front surface to the upper surface of the horizontal portion of the power supply truck 204. The cooling water pipes 214b are connected to the two cooling water pipes 214a mounted to the front surface of the heater main body 203A and the two cooling water pipes 214a mounted to the front surface of the heater main body 203B through S"connection flanges 223, and are opened/closed by valves 227. The upper portions of the cooling water pipes S 15 214b are guided to the upper surface of the RF power supply 216, as shown in FIG. 14, and are guided, together with a busbar 225, by a cable bearer 226 from this portion.

About eight induction heating apparatuses each having the above arrangement are installed along the rolling line. When the heating target plate 206 that has been conveyed on the convey rolls 207 passes through the cylindrical heating path 213, it is entirely induction-heated by the solenoid coil 212 and is temperature-increased. In this manner, the temperature of the entire heating target plate 206 gradually increases while the heating target plate 206 i-i; 26 sequentially passes through the plurality of induction heating apparatuses 201.

To perform maintenance, inspection or component exchange, of the induction heating apparatus 201, for example, to perform maintenance of induction heating apparatuses 201A and 201B, as shown in FIG. 19, the driving wheels 218 attached to the power supply truck 204 are rotated to make the induction heating apparatus 201 travel on the e: 10 rails 208a, 208b, 208c, 208d, 208h, so that the induction heating apparatus 201 is retreated from the rolling line.

The L-shaped axle lifting guides 221 extend from the lower portion of the front surface of the vertical 15 portion of the power supply truck 204, as shown in FIG. 16, and the power supply truck 204 and the heater trucks 202A and 202B are connected to each other.

Hence, the axles 210 on the rear wheels 209b side of the heater trucks 202A and 202B are guided by the axle lifting guides 221 to float the rear wheels 209b above the rails 208a, 208b, 208c, 208d, More specifically, the induction heating apparatus 201 is supported by the driving wheels 218 of the power supply truck 204 and the front wheels 209a of the heater trucks 202A and 202B to distribute its weight between the front and rear portions, so that it can travel stably.

27 In this case, as shown in FIG. 19, when the heater main body 203A of the induction heating apparatus 201A is to be exchanged and other heater main bodies are to be only inspected, first, the valves 227 of the cooling water pipes 214b are closed and the connection flanges 223 connected to the cooling water pipes 214b are removed to disconnect the cooling water pipes 214b, as shown in FIG. 14. Then, the driving wheels 218 of the power supply truck 204 are rotated to move the power 10 supply truck 204 backward together with the heater truck 202B. As shown in FIGS. 17 and 18, the rear wheels 209b of the heater truck 202A are lowered as their axle 210 is disengaged from the axle lifting guides 221, so that the heater truck 202A is supported S S 15 on the rails 208a and 208b with the four wheels and stopped.

While the heater truck 202A is separated and stopped in this manner, when the power supply truck 204 and heater truck 202B are moved backward, the front wheels 220 attached to the distal end of the bottom surface of the horizontal portion of the power supply truck 204 travel on the rails 211a and 211b on the upper surface of the heater main body 203A. Then, the front wheels 220 disengage from the rails 211a and 211b to travel on the rails 211c and 211d attached to the upper surface of the vertical portion of the heater truck 202A, and are stopped, as shown in FIGS. 17 28 and 18. The power supply truck 204 is thus supported by the vertical portion of the L-shaped heater truck 202A. Therefore, the inverted L-shaped power supply truck 204 having a heavy upper portion and attached with the RF power supply 216 can be prevented from falling.

Subsequently, the heater main body 203A placed on the heater truck 202A separated from the power supply truck 204 is hoisted by a crane 228 and moved, as shown ~10 in FIG. 18. Another heater main body 203A to replace *is loaded and placed on the heater truck 202A, thus ending exchange. When another heater main body 203B or the heater main bodies 203A and 203B of the adjacent induction heating apparatus 201B are to be inspected, since the adjacent induction heating apparatus 201A to 201C are placed in an offset manner, as shown in FIG. 19, a sufficiently large space where the operator can work is ensured, and the operation can be performed i 9 easily.

Once exchange or inspection is ended, the driving wheels 218 are rotated to move the power supply truck 204 forward. The power supply truck 204 abuts against the stopped heater truck 202A, and the rear wheels 209b move upward as they are guided by the axle lifting guides 221, as shown in FIG. 14. After that, the heater truck 202A is integrally connected to the power supply truck 204 to move forward to return to the a~ 29 rolling line.

In the above explanation, the two heater trucks 202A and 202B on which the heater main bodies 203A and 203B are placed are connected to one power supply truck 204. However, one or three heater trucks may be connected to one power supply truck.

As has been described above, according to the induction heating apparatus of the present invention, the heater and the RF power supply are integrally attached to the truck. For maintenance, the induction heating apparatus is retreated from the rolling line to allow repair or exchange. The line need not be stopped, and a large work space can be ensured, so that the .workability can be improved.

15 The heater main body and the power supply form V9000 7 separate components. For maintenance, the heater main oeeo body and power supply are retreated from the rolling line. Then, the heater main body is separated from the power supply, and the heater main body is conveyed to a separate place to allow repair or exchange. Therefore, the workability can be further greatly improved.

Since the plurality of heater main bodies and one power supply truck are combined to share one RF power supply, the structure can be downsized, and the apparatus is allowed to travel stably. When the power supply truck and heater truck are to be connected and traveled, the weight is distributed between the front and rear wheels while the rear axle of the heater truck located at an intermediate portion floats from the rails. Therefore, a heavy apparatus can travel stably.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

I*O* O

Claims

2. An apparatus according to claim i, wherein said refractory material layer has flat blocks each formed with said medium path, and arcuated blocks each 04 formed with said medium path.
3. An apparatus according to claim 2, wherein *said flat blocks and said arcuated blocks are made of castable cement. An apparatus according to claim 2, further comprising insulating support plates respectively formed on outer circumferences of said flat blocks and 9G*9 said arcuated blocks.
5. An induction heating apparatus comprising: a a solenoid coil for heating a heating target; and a refractory material layer formed on an inner side of said solenoid coil and formed by combining a plurality of blocks.
6. An apparatus according to claim 5, wherein said plurality of blocks are made of castable cement.
7. An apparatus according to claim 5, further comprising insulating support plates respectively formed on outer circumferences of said plurality of 32 *r a 5* 4 a a., yap. S S S a. blocks.
8. An induction heating apparatus comprising: a solenoid coil for heating a heating target; a refractory material layer formed on an inner side of said solenoid coil; and skid beams formed to project toward said refractory material layer along a convey direction of the heating target.
9. An apparatus according to claim 8, wherein said refractory material layer is formed with a medium path where cooing water is to be passed.
10. An apparatus according to claim 9, wherein said refractory material layer has flat blocks each formed with said medium path, and arcuated blocks each formed with said medium path.
11. An apparatus according to claim 10, wherein said flat blocks and said arcuated blocks are made of castable cement.
12. An apparatus according to claim 10, further comprising insulating support plates respectively formed on outer circumferences of said flat blocks and said arcuated blocks.
13. An induction heating apparatus comprising: a truck movable on a rail placed in a direction substantially perpendicularly intersecting a convey direction of a heating target; a heater formed on said truck to heat the heating 33 target; and a power supply formed on said heater to supply power to said heater.
14. An induction heating apparatus comprising: a heater formed on a first truck movable on a rail placed in a direction substantially perpendicularly intersecting a convey direction of a heating target, to heat the heating target; and a power supply formed on a second truck movable on 10 said rail to supply power to said heater, wherein said first truck is separatably connected .e to said second truck such that said power supply is located on said heater. e An apparatus according to claim 14, wherein said second truck is provided with an axle lifting guide for floating a rear wheel of said first truck from said rail when said first and second trucks are to be connected to each other.
16. An induction heating apparatus comprising: heaters respectively formed on first trucks movable on rails placed in a direction substantially perpendicularly intersecting a convey direction of a heating target, to heat the heating target; and a power supply formed on a second truck movable on said rails to supply power to said heaters, wherein said first trucks are separatably connected to said second truck such that said power 34 supply is located on said heaters.
17. An apparatus according to claim 16, wherein said second truck is provided with axle lifting guides for floating rear wheels of said first trucks from said rails when said first and second trucks are to be connected to each other.
18. An induction heating apparatus, substantially as hereinbefore described with reference to FIGS. 2 to 19 of the accompanying drawings. Dated this 23rd day of March 1999 KABUSHIKI KAISHA TOSHIBA and KITASHIBA ELECTRIC CO., LTD. e By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia S eo