JP3359382B2 - Heat peeling device for metal surface coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for heat-peeling a metal surface film, which is capable of efficiently and locally electromagnetically heating only a metal surface so that a film applied on the metal surface can be easily peeled and removed. More particularly, the present invention relates to an apparatus for heat-peeling a metal surface film suitable for use in heat-peeling a metal surface film at a joint (welding) portion between a floor plate and a side wall of various tanks.

[0002]

2. Description of the Related Art A coating, a coating film or an adhesive film (hereinafter collectively referred to) applied to a metal surface forming a side wall (outer wall, inner wall) and a floor plate (bottom annular plate) in various large-diameter tanks such as oil and gas. The coating may be required to be peeled off for repair or repair. Conventionally, as a method of peeling off the coating on the metal plate, a method of physically peeling, a method of peeling by softening with a solvent, a method of softening the coating by heating, and the like are known.

[0003] However, the above-described conventional method of peeling off a film applied on a metal plate has the following problems. First, since the method of physically peeling off the film is performed by sandblasting, a vibration tool, or spraying high-pressure water, there is a problem that dust, vibration, noise, or rust is generated. In particular, in the method using sandblasting, dust is generated, so that the working environment is poor, the time required for peeling work and the like is increased, and the metal plate is greatly worn. In addition, the method of stripping the coating with a solvent or a stripping agent has a problem in that harmful gas is generated and poisoning by the solvent is easily caused. Furthermore, the method of softening and peeling the film by heating such as flame or electric heat requires measures against combustion gas, and it takes time to heat the entire metal, requiring a large amount of energy and heating the metal to a high temperature. Therefore, there is a problem that the mechanical strength of the metal tends to decrease.

[0004] In addition, these conventional peeling methods have a problem that it is difficult to peel off a film at a corner portion such as a welded portion between a floor plate and a side wall.

[0005] In view of these problems, the following proposals have recently been made. First, Japanese Patent Application Laid-Open No. 633-100000 proposes a technique in which a metal is heated to a temperature at which the mechanical strength is not impaired by induction heating, and the coating is peeled from the steel pipe. Secondly, Japanese Patent Application Laid-Open No. 2-30087 proposes a technique of peeling off a film by self-heating a metal surface by high-frequency induction heating. Thirdly, Japanese Patent Publication No. 63-67100 proposes a technique in which a metal surface is heated by induction heating to reduce the adhesive strength of a lining material or a thick-film coating material and to peel off the material. Fourth, the present inventor disclosed in
No. 7091 proposes a method in which only a metal surface is locally and efficiently heated by electromagnetic induction to perform peeling.

[0006]

However, in any of the above-mentioned technologies which have been conventionally proposed, in any case, the coating film cannot be peeled off at a corner portion such as a joint portion between a floor plate and a side wall. That is, the technique disclosed in Japanese Patent Application Laid-Open No. 633-100000 is intended for a metal pipe and cannot be applied to a tank having a large area such as a tank and having a coating portion at a corner thereof. Further, the technique disclosed in Japanese Patent Application Laid-Open No. 2-30087 is capable of peeling a flat film surface, but does not disclose peeling of a film at a corner. Furthermore, in these prior arts, in order to obtain a high output while reducing the size of the device, the device becomes extremely hot and cannot withstand long-time use. Furthermore, Japanese Patent Application Laid-Open No.
The technology of 267091 is different from the conventional technology described above, in that it can process a large area at a time using high-frequency induction heating, can withstand long-time use, and has good operability in a tank. Although it can be used efficiently, peeling of the film at the corner could not be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to locally and efficiently heat only a metal surface at a corner portion such as a joint portion between a floor plate and a side wall of various tanks, and to easily perform heating at the corner portion. It is an object of the present invention to provide an apparatus for heat-peeling a metal surface film capable of peeling and removing the film.

[0008]

In order to achieve the above object, the first aspect of the present invention provides a first contact plate and a second contact plate which intersect a main body at a predetermined angle. It comprises an electromagnetic induction coil and a core provided inside the first and second contact plates, and includes an electromagnetic induction section supported below the main body, and a high-frequency generator built in the main body, Position inside the first contact plate in the electromagnetic induction section
To roughly wind the electromagnetic induction coil to be
The electromagnetic induction coil located inside is densely wound . Further, the invention according to claim 2 is characterized in that the electromagnetic induction
Part is swingably attached below the main body.
It is. Further, the invention according to claim 3 is the electromagnetic induction
Part consists of two sets of electromagnetic induction coil and core.
It is. The invention according to claim 4 is configured to have two sets of high-frequency generators corresponding to the two sets of electromagnetic induction coils. Further, the invention according to claim 5 is characterized in that:
At the bottom of the main unit, change the direction of the casters by 90 degrees
There is an attached configuration.

[0009]

In a state where the first and second contact plates of the electromagnetic induction unit are in contact with the coating applied on the surface near the joint (welded portion) of the floor plate and the side wall of the tank or the like, the high frequency High frequency power is supplied to the electromagnetic induction coil from the generator, and only the surface near the joint between the floor plate and the side wall is locally self-heated, whereby the coating is heated and peeled off. Usually, the coating is turned up by heating and peels off spontaneously, but if it adheres firmly and does not peel easily, it is peeled off using a scraper or the like.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a partially cut-away side view showing a state in which a heating and peeling apparatus for a metal surface coating according to a first embodiment of the present invention is operated, and FIG. 1B is viewed from a direction A in FIG. FIG. FIG. 2 is a side view showing the state of the apparatus shown in FIG. 1 during transportation. FIG. 3 is an enlarged sectional view showing an example of the electromagnetic induction section. In the drawings, reference numeral 1 denotes a device for heating and separating a metal surface coating such as a tank, and includes a main body 10 and an electromagnetic induction section 20.
And a control unit 30. The electromagnetic induction section 20 for heating the metal plate and the control section 30 including the high-frequency generation section for supplying high-frequency power to the electromagnetic induction section 20 are integrally formed close to each other. That is, the electromagnetic induction unit 2
Reference numeral 0 is connected to the lower part of the main body 10 having the control unit 30 therein via a connection arm 40 with an appropriate gap. Also, in order to be able to adjust the positional relationship between the main body 10 and the electromagnetic induction unit 20, the electromagnetic induction unit 20 is configured as shown in FIG.
It is attached to the connecting arm 40 so that it can swing in the direction of arrow B in FIG. In addition, when the electromagnetic induction unit 20 and the control unit 30 are integrated in close proximity to each other, the size of the entire device is reduced, and the loss of electromagnetic waves is reduced. Here, the term “integrated” means that the device is integrated when the device is used, and does not mean that the device is always physically integrated.

The main body 10 is provided with a handle 41 formed by projecting a part of the connecting arm 40 above the main body 10, a cooling hole 11 for radiating heat inside the main body 10, and the apparatus 1. A caster 50 is provided for the purpose. Among them, the caster 50 is connected to the main body 10 via a hinge-shaped fitting 51.
1 (a), (b) and FIG.
The direction can be changed by 90 degrees as shown in FIG.
Thus, when the apparatus 1 is used, the casters 50 are
(A) and (b) in the horizontal direction (arrow C
Direction), and at the time of transporting the apparatus, the casters 50 are moved in the front-rear direction (direction of arrow D) as shown in FIG.

As shown in FIG. 3, the electromagnetic induction section 20 includes a first contact plate (bottom plate) 21 and a second contact plate (side plate) 22, which intersect substantially at right angles, an electromagnetic coil 23, and a core (through-hole). Magnetic body)
24. First and second contact plates 21,
22 is a metal floor plate 61 and a side wall 62 (metal plate 61,
62) It is brought into contact with the coating film 60 (normally having a thickness of about 0.1 to 5.0 mm) applied thereon. First and second contact plates 21,
22 is preferably formed of a material having excellent high-temperature resistance and impact resistance. Examples of such a material include a heat insulating plate made of heat-resistant polyimide and glass fiber (KV3 manufactured by Brandenburger), an inorganic heat insulating plate (Super Insulation ROSNA manufactured by Hiroden Kagaku), and the like. First and second contact plates 2 made of these materials
When the metal plates 61 and 62 are used, the heat of the metal plates 61 and 62 can be transferred without interrupting the high-frequency electromagnetic induction operation described later.
Transmission to the device, and the device can be operated for a long time.
In particular, in order to heat the metal plates 61 and 62 quickly and to a high temperature, it is necessary to bring the electromagnetic induction coil 23 as close as possible to the metal plates 61 and 62 and reduce the distance between them. When the coil 23 is approached, the heat of the heated metal plates 61 and 62 is transmitted to the core 24 and the core 2
4 will degrade the magnetization performance. However, if the above-described heat insulating plate made of heat-resistant polyimide and glass fiber is used, the core 24 can be brought close to the metal plates 61 and 62 without deteriorating the magnetization performance, and rapid and high-temperature heating can be performed.

The core 24 functions to absorb the magnetic lines of force diverging into the space above the electromagnetic induction coil 23 downward and to be absorbed by the metal plate, and is made of an insulating magnetic material. As shown in (1), they are mounted on the first and second contact plates 21 and 22 which cross at substantially right angles. Therefore, the electromagnetic induction coil 23 is wound around the core 24 in both directions of the floor plate 61 and the side wall 62, thereby generating a magnetic field in two directions of the floor plate 61 and the side wall 62. The feature of the present embodiment lies in that the magnetic field is made orthogonal as described above, and the coating on the welded portion, which is the joint between the floor plate 61 and the side wall 62 such as a tank, is effectively heated, and the coating is reliably separated. . Here, since the core 24 is vulnerable to impact, in order to reduce the impact to the core 24, for example, a silicon plate of about 0.5 mm or the like is provided between the core 24 and the first and second contact plates 21 and 22. (Not shown) is provided to reduce the impact applied to the core 24. In addition, the electromagnetic induction coil 23 is provided on the side facing the floor plate 61 roughly.
2 is densely wound on the side opposite to the floor plate 61.
And the heating energy corresponding to the thickness of the side wall 62 can be obtained.

The control section 30 is mounted inside the main body 10 and includes a high frequency generator (not shown) for generating high frequency power and a control section for performing various controls of the apparatus. The high frequency generator of the controller 30 is connected to the electromagnetic induction coil 23. Accordingly, the high-frequency power generated by the high-frequency generator is supplied to the electromagnetic induction coil 23 to generate an alternating magnetic field, and an eddy current as shown in FIG. , The floor plate 61 and the side wall 62, particularly the welded portions thereof, generate heat.

The frequency of the high-frequency power generated by the high-frequency generator is preferably 9 to 30 KHz.
Preferably, the frequency is set to 20 kHz. Above 30 KHz is not realistic. If the frequency is lower than 9 KHz, the floor plate 61 and the side wall 62 are deeply heated.
In addition, the material located on the opposite side of the side wall 62 suffers from thermal degradation, which is not preferable, and the efficiency is further deteriorated, which is not preferable. Note that there is a relationship expressed by the following equation (1) between the high frequency f (Hz) and the effective depth of eddy current generation (heated depth) δ (in) (where μ is the magnetic permeability) , Ρ is the electrical resistance of the steel).

[0016]

(Equation 1)

Therefore, by substituting the value of the frequency f into the above equation (1), an approximate value of the heated depth can be obtained. For example, when the frequency f is 11.5 KHz, the heated depth is 0.46 mm.

It is preferable to use a high-frequency generator capable of supplying a large amount of power in order to shorten the heating time. FIG. 5 shows an example of the circuit configuration of the high frequency generator.
In the figure, three-phase alternating current (200 V, 60 to 100
A) 32 is DC-converted by a rectifier 33, smoothed by a reactance 34 and a capacitor 35, and is subjected to a high-frequency pulse current P (9 to 9) by a power transistor 36.
30KHz, average current 200A)
3.

Next, a description will be given of a heat peeling method using a heat peeling apparatus for a metal surface coating having the above-mentioned structure. First, as shown in FIG. 1A and FIG. 3, the device 1 is moved so that the first and second contact plates 21 and 2 of the electromagnetic induction unit 20 are moved.
2 is brought into contact with the coating 60 applied on the surface near the joint (welded portion) between the floor plate 61 and the side wall 62. Next, high-frequency power is supplied to the electromagnetic induction coil 23 from the high-frequency generator of the controller 30 to locally self-heat only the surface near the joint between the floor plate 61 and the side wall 62, thereby causing the coating 60 to be peeled off by heating. . Usually, the coating is turned up by heating and peels off spontaneously, but a part which adheres firmly and is hard to peel off can be easily peeled off by using a scraper or the like. The processing time is 1 to 60 seconds and the processing temperature is 5
It is preferable to control the control unit 30 so that the temperature is 0 to 300 ° C.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 (a) and 6 (b). In the present embodiment, the intersection angle between the first contact plate 21 and the second contact plate 22 of the electromagnetic induction unit 20 is set to an angle smaller than 90 degrees, for example, an acute angle of about 80 degrees to less than 90 degrees. , Can be swung by an angle smaller than 90 degrees. The reason for this configuration is that the tank has a vertical side wall 62,
There are tanks in which the floor plate 61 is raised toward the center and those which are lowered. In the case of a tank in which the floor plate 61 is raised toward the center, the first and second abutments are provided. This is because the intersection angle between the plates 21 and 22 needs to be acute. That is, in order to effectively heat the coating at the joint between the floor plate 61 and the side wall 62, the intersection angle between the first and second contact plates 21 and 22 is set to be smaller than the intersection angle between the joint between the floor plate 61 and the side wall 62. Then, the contact plates 21 and 22 are
And the side wall 62 is securely contacted.

In this case, the first and second contact plates 21 and
2 is smaller than the intersection angle between the floor plate 61 and the side wall 62, so that the electromagnetic induction unit 20 can swing, and the first and second contact plates 21 and 22 are alternately arranged on the floor plate 61.
And the floor plate 61 and the side wall 6 in contact with the side wall 62.
The peeling operation is advanced while checking the heating state of No. 2. When the tank floor plate 61 is lowered toward the center, the first and second abutment plates 21 and 22 in the above-described first embodiment are arranged so that the electromagnetic induction portions 20 are substantially orthogonal to each other. By swinging, the work can be performed in the same manner as in the above-described second embodiment.

Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the electromagnetic induction unit 20
Are combined with two sets of the electromagnetic induction coil 23 and the core 24, so that a large heating energy can be obtained. Further, the heating state can be adjusted by supplying currents of different magnitudes to the two sets of coils 23 in accordance with the thickness of the floor plate 61 and the side wall 62, or by changing the current supply time. Further, when two sets of coils and cores are provided, two sets of high frequency generation circuits in the control unit may be provided, and each coil may be driven by another high frequency generation circuit. Thereby, the load on the high frequency generator is reduced, and the device can be used for a long time. In addition, since the problem of insufficient capacity of a capacitor or a transistor is solved, it is possible to improve the processing capacity and increase the processing area.

Next, FIGS. 8A and 8B and FIG.
A fourth embodiment of the present invention will be described based on (a) and (b). In this embodiment, the core 24 is formed to have an inverted F-shaped cross section and can rotate 90 degrees in the direction of arrow A and 180 degrees in the direction of arrow B, although not shown. In this way, the state of the induced current can be changed from FIG. 8B to FIG. 9B, and the mode of heating can be changed.

The present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented within the scope of the present invention. For example, the first and second abutment plates 21 and 22 may be configured by bending a single plate, or may be configured by bonding two plates at an intersection. In addition, the control unit 30 needs to be cooled for continuous use.
Therefore, for example, a cooling radiator using a cooling heat pipe 31 may be attached to the surface of the control unit to suppress the temperature rise of the control unit 30. In the heat pipe 31, a working fluid is sealed inside the pipe, and the working fluid is heated at one end of the pipe to evaporate, moves at a high speed to the other end of the pipe, releases latent heat, and condenses. Conducts heat propagation at high speed. A heat pipe can conduct heat several hundred times more than a metal rod of the same diameter. It is preferable to attach the fins 32 to the heat pipe in order to increase heat radiation efficiency. As the heat pipe, any of bottom heat, horizontal heat and top heat can be used. The use of the heat pipe suppresses a rise in the temperature of the control unit, avoids a failure of the transistor of the control unit due to the rise in temperature, and enables the device to be used for a long time.
Further, at one or more places, for example, six places, of the first and second contact plates 21 and 22, a marker member having a color different from that of the contact plates 21 and 22 is placed at a depth of about ／ of the bottom plate. When the contact plates 21 and 22 are worn due to use, the marker member is exposed, so that it is easy to notify that the contact plates 21 and 22 need to be replaced.

Experimental Example The vinyl ester resin-based coating on the corner of the crude oil storage tank was removed by a coating stripping device. The crude oil tank was preliminarily removed of all oil, moisture and sludge, and was subjected to a film peeling treatment having an average film thickness of 1,000 μm with the anticorrosion film being exposed. The film peeling device is placed in contact with the corner where film peeling is required, 20 KHZ, 30 KVA high frequency power is passed through the electromagnetic induction coil and held for 40 seconds, and then the film peeling device is moved to the next peeling portion and moved. The coating on the heated portion was peeled off with a metal scraper. Peeling was easy. When the temperature under the vinyl ester resin-based coating was measured on a test basis, it was found that
It was 50 degrees. There was no evidence of damage to the asphalt sand beneath the tank floor, the Denso tape to prevent moisture intrusion on the sketch plate on the outer surface of the side wall, or the outer surface coating on the side wall. The bottom plate of the peeling device used an inorganic heat insulating material. After about 4 hours of use, the core temperature does not exceed 200 degrees,
No condition that degraded the performance of the core occurred.

[0026]

As described above, according to the apparatus for heat-peeling a metal surface coating of the present invention, only the joint between the floor plate and the side wall of various tanks and its vicinity can be locally and efficiently heated by electromagnetic induction. And the coating applied to the metal surface in the vicinity thereof can be easily peeled and removed. In addition, since the device can be used efficiently for a long time even though the device is small, it is excellent in operability and economy.

[Brief description of the drawings]

FIG. 1 (a) is a partially cut-away side view showing a state in which a heating and peeling apparatus for a metal surface coating according to a first embodiment of the present invention is operated, and FIG. 1 (b) is viewed from a direction A in FIG. FIG.

FIG. 2 is a side view showing a state in which the apparatus of FIG. 1 is being transported.

FIG. 3 is a cross-sectional view illustrating an example of an electromagnetic induction unit.

FIG. 4 is a developed view showing a state of an induced current by the electromagnetic induction unit shown in FIG. 3;

FIG. 5 is a circuit diagram showing an example of a high-frequency generator of the device invention shown in FIG.

FIGS. 6A and 6B are cross-sectional views of an electromagnetic induction unit according to a second embodiment of the present invention.

FIG. 7 is a sectional view of an electromagnetic induction unit according to a third embodiment of the present invention.

FIG. 8A is a sectional view of an electromagnetic induction unit according to a fourth embodiment of the present invention, and FIG. 8B is a developed view showing a state of an induced current by the electromagnetic induction unit shown in FIG.

FIG. 9 is a bottom view of an example in which the electromagnetic induction portion is formed long along a welding line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Device 10 ... Main body 11 ... Cooling hole 20 ... Electromagnetic induction part 21 ... First contact plate (bottom plate) 22 ... Second contact plate (side plate) 23 ... Electromagnetic induction coil 24 ... Core 30 ... Control part 40 ... Connecting arm 41. Handle 50. Casters 51.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-30087 (JP, A) JP-A-4-269709 (JP, A) JP-A-56-91870 (JP, A) 11666 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B44D 3/16

Claims (5)

(57) [Claims] A first contact plate and a second contact plate intersecting the main body at a predetermined angle;
It comprises an electromagnetic induction coil and a core provided inside the first and second contact plates, and includes an electromagnetic induction section supported below the main body, and a high-frequency generation section built in the main body. A position inside the first contact plate in the electromagnetic induction portion;
Coarsely wound the electromagnetic induction coil to be placed, and the second contact plate
A heating and peeling apparatus for a metal surface coating, wherein an electromagnetic induction coil positioned inside the metal is densely wound . 2. The electromagnetic induction section is swung downwardly of the main body.
The apparatus for heat-peeling a metal surface coating according to claim 1, which is movably mounted . 3. The electromagnetic induction part comprises two sets of electromagnetic induction coils.
The apparatus for heat-peeling a metal surface coating according to claim 1, comprising: 4. The apparatus for heat-peeling a metal surface coating according to claim 3, further comprising two sets of high-frequency generators corresponding to said two sets of electromagnetic induction coils. 5. A caster is mounted on a lower portion of the main body,
5. A method according to claim 1, wherein the mounting is changed by 90 degrees.
4. The apparatus for heat-peeling a metal surface coating according to claim 1.