KR101688072B1 - Induction Heating system for Heating-bolt - Google Patents

Abstract

The present invention provides an induction heating system for a heating bolt which includes: the heating bolt which connects a first combining unit and a second combining unit facing each other by a thread formed on each outer circumferential side of both end parts with a hollow circular pipe shape and includes an installation hole in an inner center thereof along a longitudinal direction; a heating unit which is inserted into the installation hole along the longitudinal direction of the heating bolt, heats the heating bolt by induction heating through power supplied from a main body, and changes the extensibility of the heating bolt to extend or compress the heating bolt according to a variation of temperature; and a core unit which is combined in the inner side of the heating unit and increases an output by the induction heating in a preset region of the heating unit. Accordingly, the present invention can prevent an industrial disaster.

Description

[0001] Induction heating system for heating bolt [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating system for a heating bolt, and more particularly, to a heater fastening apparatus for a high frequency induction heating apparatus for heating a heating bolt through dielectric heating or induction heating using a high frequency electromagnetic field.

Large turbines, high-pressure valves, and internal combustion engines used in power plants and various industrial plants are tightened using heating bolts.

Such a heating bolt is a bolt member having a hollow shape and is heated and stretched through an induction heater or the like during fastening or detachment thereof in order to maintain a sufficient coupling force in a large turbine or the like operated at high temperature or high pressure.

The amount of heating bolts heated is a very important factor for the heating bolts to maintain proper bonding force. If the heating bolts are excessively heated or stretched too little, they may be damaged due to heating bolt breakage, casing deformation, loosening of the nut, It may cause problems such as poor bonding performance.

The induction heater used to extend the heating bolt is called a radio heater in such a way that an object is placed in a strong electromagnetic field.

The high-frequency heating method includes dielectric heating (induction heating) and induction heating (induction heating).

Here, dielectric heating is a principle in which an object to be heated is placed in a high-frequency electric field to cause heat loss due to dielectric loss of the dielectric material. Induction heating is a method in which, when an electric conductor is placed in a high frequency magnetic field, Or by self-heating due to loss of hysteresis.

This type of dielectric heating method can be applied to the drying and bonding of wood, the vulcanization of rubber, the molding of synthetic resin, the bonding of vinyl film (high frequency bonding), the drying of fibers, the processing of bamboo products, (Microwave oven) and so on. Generally, the higher the frequency, the higher the calorific value. However, since the heated body is not heated evenly, the frequency used ranges from several KHz to several GHz depending on the object to be heated. There are flat electrode, lattice electrode and coaxial electrode for the high-frequency electrode, and a cavity resonator when the frequency is high. This heating method is characterized in that even if the insulator having a low thermal conductivity is an object to be heated, the efficiency of the object to be heated is good due to the heat generated by the object to be heated, and the desired portion can be selected and heated.

In addition, the induction heating method is used for melting, quenching, annealing, welding, brazing, and forging of a metal alloy, and for producing a molten refined single crystal of germanium or silicon in the semiconductor industry. As the frequency increases, the eddy current flows only on the surface of the conductor and does not penetrate into the inside of the conductor. Therefore, a relatively low frequency is used for melting and a relatively high frequency is used for heating only the surface such as metal surface quenching . This heating method is characterized in that a metal having a high thermal conductivity can be locally heated or melted, and a metal melting with high purity is performed in a vacuum.

Therefore, when the heating bolt is heated by the induction heating method, the heating bolt can be easily heated and the heating time can be shortened, so that it is advantageous that the heating bolt fastened to the large plant can be easily fastened or detached.

However, it is difficult to accurately measure the temperature of the heating bolt according to the set interval of the heating bolt while heating the heating bolt through the high frequency induction heating apparatus, so that it is pointed out that the stress or elongation due to the physical properties of the heating bolt changes .

Therefore, it is difficult to measure the deformation of the physical properties such as the tensile strength and the yield strength as the heating bolts are locally overheated in the heating process only when the heating bolts are stretched according to the elongated amount of the heating bolts. Therefore, There are problems such as occurrence of a safety accident by reusing the bolt, or serious damage to the entire plant.

Further, since it is difficult to partially or wholly heat the heating bolt according to the internal shape or structure of the heating bolt, there is a problem that the same heat must be applied as a whole.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and in particular, it is an object of the present invention to provide a heating part having a core part in a heating part to improve the output partly or wholly heating, The output can be adjusted according to the number or size, thereby preventing the local physical properties of the heating bolt from being deformed, keeping the extension rate uniform by heating to a constant temperature, thereby preventing safety accidents or industrial accidents The present invention provides an induction heating system for a heating bolt.

According to an aspect of the present invention, there is provided a hollow pipe having a hollow pipe shape, wherein threaded portions are formed on outer circumferential surfaces of both end portions to fasten first and second fastening portions opposed to each other, A heating bolt formed therein; A heating bolt inserted into the installation hole along the longitudinal direction of the heating bolt and heating the heating bolt by induction heating through a power source supplied from the main body and changing the extension rate of the heating bolt to be tensioned or compressed according to a temperature change, And a core portion coupled to the inside of the heating portion to increase an output according to induction heating in a predetermined region of the heating portion.

The core portion may be formed of a material containing at least one selected from copper-zinc based ferrite, nickel-zinc based ferrite and manganese-zinc based ferrite.

The core portion may be selectively detachably coupled to one or a plurality of predetermined regions formed on the heating portion.

The induction heating system for the heating bolt further includes an insulating part which is disposed to surround the outside of the heating part and at least simultaneously surrounds the core part in one or a plurality of predetermined areas formed on the heating part to fix the position of the core part .

The main body may include a coolant supply line connected to an external water supply facility to store or supply the supplied coolant to a region requiring cooling.

The induction heating system for the heating bolt further includes a power cable provided between the main body and the heating unit to connect a power source to be supplied to the heating unit from the main body and a connector provided at one end of the heating unit and connected to the power cable can do.

The induction heating system for the heating bolt may further include a cooling unit for cooling the outside or inside of the power cable through the cooling water supplied from the cooling water supply line.

In the induction heating system for a heating bolt according to the present invention,

First, because the fastening bolts are fastened or removed according to the length of the heating bolts due to the temperature change, the first fastening holes and the second fastening holes can be firmly coupled,

Second, it is possible to prevent a safety accident from occurring due to a strong coupling force, prevent industrial disasters from occurring,

Third, since the internal temperature of the heating bolt can be accurately grasped, it is possible to uniformly and quickly heat the heating bolt within a range that does not deform the physical properties of the heating bolt,

Fourth, since the output according to the heating of the set portion can be improved by using the core portion corresponding to the shape of the heating bolt, the heating efficiency is increased,

Fifth, since the cooling water supply method is cooled by supplying the water without using the heat exchanger through the existing chiller, the volume of the system can be reduced and the economical operation can be expected.

1 is a perspective view schematically showing an induction heating system for a heating bolt according to the present invention.
Fig. 2 is a sectional view showing the heating bolt shown in Fig. 1 in a state in which the first binding portion and the second binding portion are fastened. Fig.
3 is a perspective view showing a state in which a heating part is inserted into the heating bolt shown in Fig.
Fig. 4 is an enlarged perspective view of the heating unit shown in Fig. 3; Fig.
5 is a side view showing a side surface of the heating unit shown in Fig.
FIG. 6 is a reference view showing a state in which the core is coupled to a predetermined region in the heating unit shown in FIG. 4. FIG.
7 is a flowchart showing a control method of the induction heating system for a heating bolt according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be noted that the drawings denoted by the same reference numerals in the drawings denote the same reference numerals whenever possible, in other drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. And certain features shown in the drawings are to be enlarged or reduced or simplified for ease of explanation, and the drawings and their components are not necessarily drawn to scale. However, those skilled in the art will readily understand these details.

FIG. 1 is a perspective view schematically showing an induction heating system for a heating bolt according to the present invention, FIG. 2 is a sectional view showing a first binding section and a second binding section into which the heating bolt shown in FIG. 1 is inserted, 2 is a perspective view showing a state in which a heating part is inserted into the heating bolt shown in Fig. 2; Fig.

1 to 3, an induction heating system 100 for a heating bolt according to the present invention includes a main body 110, a heating unit 130 connected to the main body 110 to provide high frequency induction heating, A heating bolt 140 for fixing the first binding part 30 and the second binding part 40 by being heated substantially through the heating part 130, And a core unit 150 coupled to increase the output according to induction heating.

Accordingly, the main body 110 applies the appropriate voltage and current to the heating unit 130, and at the same time, a water-cooling type cooling operation is performed.

Also, the main body 110 includes a cooling water supply line 112 connected to an external water supply facility to store or supply the supplied cooling water and supply the cooled water to an area requiring cooling. The cooling water supply line 112 is connected to, for example, a water supply directly to receive cooling water, and may store cooling water, although not shown in the drawing. The area requiring cooling may be, for example, the main body 110, the power cable 120, the heating unit 130, and the like. Since the power cable 120 is required to have a high current or voltage due to the characteristics of induction heating, it is possible to reduce the diameter of the power cable 120, thereby reducing manufacturing costs. Therefore, a cooling unit 121 for cooling the power cable 120 is provided outside or inside the power cable 120. The cooling unit 121 may be connected to the cooling water supply line 112 to cool the inside or the outside of the power cable 120 and to transfer the cooling water to the heating unit 130. The cooling water thus cooled is recovered to the main body 110 after cooling the power cable 120 and the heating unit 130, and then discharged to the outside.

In addition, the cooling water supply line 112 may be connected to the hydrant so as to supply cooling water during an emergency.

In addition, although not shown in the drawing, a power supply unit for controlling power supplied from the outside to the main body 110 is provided in the main body 110. The power supply unit supplies the current and voltage suitable for induction heating and also provides the ability to generate the appropriate frequency. In addition, the main body 110 is provided with a control unit (not shown) for controlling the current, voltage, frequency, reactive power, and the like. The control unit controls the output of the induction heating system 100 to control the heating unit 130 to operate at a uniform temperature, and also provides a function of preventing overheating. Further, the control unit senses that the heating unit 130 abnormally overheats in the coupling region of the core unit 150 or increases or decreases the rate of temperature change compared to other sections, and accordingly, the heating bolt 140 is uniformly heated Respectively. In addition, the control unit controls the heating temperature of the heating unit 130, and when the heating bolt 140 exceeds the set temperature range, the controller 130 cuts off the power of the heating unit 130, Can be controlled.

Therefore, the heating bolt 140 can be extended in a short time by the power supplied to the heating unit 130, and it is possible to reduce time and cost due to disassembly or maintenance due to fastening or detaching .

A coupling hole 111 is formed in the main body 110 at one side. The power supply cable 120 is coupled to the inside of the coupling hole 111. The coupling hole 111 is formed in a shape that is inwardly inward from one side of the main body 110. [ Of course, a terminal (not shown) to which the power cable 120 can be coupled may be exposed to the outside.

The heating unit 130 is coupled to the power cable 120. At this time, a connector 131 is provided at one end of the power cable 120 and the heating unit 130. Therefore, the power cable 10 and the heating unit 130 are selectively coupled to each other so that they can be attached and detached.

The first coupling portion 30 and the second coupling portion 40 shown in Fig. 2 may correspond to a main body and a cover (casing) of a large turbine, for example. Accordingly, the first binding portion 30 and the second binding portion 40, which must be firmly coupled by using the heating bolt 140, are fastened.

At this time, the heating bolt 140 is fastened in a heated state between the first binding part 30 and the second binding part 140, fastened in a state elongated along the longitudinal direction, The length of the heating bolt 140 is reduced and the first binding portion 30 and the second binding portion 40 are fastened together.

The heating unit 130 receives the high frequency current supplied from the main body 110 and induction heating is performed inside the heating bolt 140. At the same time, the cooling water supplied from the cooling water supply line 112 circulates Water-cooled cooling is performed.

For example, the heating unit 130 may form a high-frequency magnetic field around the heating bolt 140 through the supplied current, thereby causing eddy current loss or hysteresis loss in the high-frequency magnetic field It may be exothermic. The principle of such induction heating is well known in the art, and a detailed description thereof will be omitted.

Fig. 4 is a perspective view showing an enlarged view of the heating unit shown in Fig. 3, Fig. 5 is a side view showing a side face of the heating unit shown in Fig. 4, Fig.

4 to 6, the heating unit 130 includes an inlet line 133 and an outlet line 134. The inlet line 133 is connected to one side terminal of the power source or is supplied with cooling water. The lead line 134 is integrally connected to the lead line 133, and the other terminal of the power source is coupled or the coolant is discharged.

The lead line 133 and the lead line 134 are connected in parallel with each other with a predetermined gap 135. The gap 135 between the lead line 133 and the lead line 134 is connected to the core 150 Are selectively combined. At this time, the joining position of the heating part 130 and the core part 150 is fixed by the insulating part 132. Since the insulating portion 132 is wrapped around the core portion 150 at the same time as the heating portion 130, the outer portion is insulated and the combined position of the core portion 150 is fixed.

The core part 150 is a ferrite core and has high magnetic permeability and low conductivity. As a frequency applied to the heating unit 130 increases, an eddy current loss occurs. Therefore, a ferrite powder other than an iron plate is pressed and applied. In other words, the ferrite core generally works in a similar manner to an iron core applied to a transformer, but it is used in powder form to prevent eddy current loss at a high frequency.

The core portion 150 is formed of a material containing at least one selected from copper-zinc based ferrite, nickel-zinc based or manganese-based ferrite. In addition, the core unit 150 may be made of any material other than the ferrite based material as long as the ferrite material can improve the output.

Accordingly, when the core part 150 is coupled to the gap 135, the output of the heating part 130 around the heating part 130 coupled with the core part 150 is improved, The heating member 140 can be heated faster.

As shown in FIG. 4 or 5, when the core unit 150 is coupled to the gap 135 between the heating units 130, the output increases by at least 50% or more compared to the conventional output.

6, when the sectional area of the heating bolt 140 is different, when the core part 150 is coupled to upper and lower sections having a large cross-sectional area, the overall temperature rise of the heating bolt 140 is uniformly pulled can do. In addition, since the temperature of the heating unit can be partially regulated by adjusting the size and the coupling interval of the core unit 150, stable heating can be performed corresponding to the shape of the heating bolt 140.

For example, when the heating bolt 140 is complicated in structure or irregular in cross-sectional area, the size of the core part 150 coupled to the heating part 130 may be adjusted, or the gap between the core parts Thereby adjusting the balanced heating of the heating bolt 140 to be heated. Also, there is an effect that the heating bolt 140 can be prevented from being excessively overheated.

Accordingly, since the temperature of the heating bolt 140 is uniformly increased by selectively coupling the core unit 150 to the heating unit 130, there is no problem in safety even if the heating bolt in a state of being fastened or detached is reused. There is an effect that an accident can be prevented beforehand.

In addition, since the cooling water is supplied from the water supply and the recovered cooling water is discharged to the outside, the overall volume or weight of the induction heating system for the heating bolt can be reduced, unlike the case where the existing heat exchanger is provided using the chiller. It is expected that the effect becomes easy. In addition, since the current transfer (CT) is not required as well as the chiller, the workability can be increased and the operation cost or manufacturing cost can be reduced. Of course, the chiller and current transformer can be selectively removed, taking into account coverage and usage.

7 is a flowchart showing a control method of the induction heating system for a heating bolt according to the present invention.

Referring to FIG. 7, the control method (S100) of the induction heating system for a heating bolt of the present invention includes a step (S110) of inputting information on size, material, strength and elongation according to the type of heating bolts to be fastened (S120) heating the heating bolt through the heating unit on the basis of the information of the heating bolt, and measuring a temperature for each interval set through the temperature sensor disposed along the longitudinal direction in the internal mounting hole of the heating bolt (S130), and controlling the heating unit through the control unit in response to the temperature change of the heating bolt (S140).

First, in step S110, information about the size such as length, width, and diameter is input according to the type of the heating bolt, and information about the tensile strength, yield strength, yield ratio, and the like is also input. For example, in the case of the heating bolt manufactured as a prefabricated product, such information may be converted into data by setting the kind of the heating bolt in the control unit without inputting it separately.

Through the input information, the control unit distinguishes the heating bolts and limits the upper limit heating temperature based on the information.

Then, the heating bolt is heated through the heating unit (S120).

In step S120, the heating bolt is heated in a preset time, a predetermined temperature, and a set frequency range. In step S120 of heating the heating bolt, cooling water supplied from outside flows into the heating unit After the heating unit is cooled, it is recovered to the main body and then discharged to the outside.

At this time, the step of heating the heating bolts (S120) includes a step S121 of removing and attaching the core parts to be coupled by adjusting the positions of the core parts coupled to the heating part and the number of coupling parts. In the step of removing and attaching the core part (S121), the heating output is controlled according to the inner shape and the cross-sectional area of the heating bolt, and the core part is selectively Detachable. In the step of heating the heating bolts (S120), the cooling water supplied from the outside flows into the heating unit, and after cooling the heating unit, the heating water is recovered to the main body and then discharged to the outside.

In the temperature measurement step (S130), the temperature sensor measures the temperature of each section of the heating bolt and transmits the measured temperature to the controller. Of course, the temperature measurement step S130 may control the temperature sensor units to transmit the measured temperature in real time or to transmit the measured temperature at the set time. The temperature sensor unit may measure the temperature by contacting or noncontacting with the heating bolt.

The step of controlling the heating unit (S140) may include setting the time, temperature, current, voltage, and frequency of heating the heating bolt by the heating unit through the controller based on the data obtained in the temperature measuring step (S130) (S141) adjusting at least one of the heating bolts to a predetermined heating temperature of the heating bolts.

The temperature control step S141 is performed to increase the temperature of the low temperature section in the temperature measuring step S130 and to lower the temperature of the high temperature section. Therefore, there is an effect that the heating bolt can be uniformly heated and prevented from being overheated in a local portion. Of course, in the temperature control step S141, a process of regulating the position and the number of the core part again so as to uniformly heat the heating bolt with a constant heating output may be performed.

In the temperature control step S141, when at least one of the tensile strength, the yield strength, and the elongation of the heating bolt exceeds a predetermined range, the power of the heating unit may be cut off or the power output may be decreased. In addition, the temperature control step S141 includes an alarm step S142 for notifying the operator that the power is turned off when the power is turned off.

Therefore, since the temperature of the heating bolt is uniformly increased, there is no problem in safety even if the heating bolt in a state of being fastened or detached is reused, and safety accident can be prevented in advance.

Further, since the operator can quickly grasp the power-off state of the heating unit, it is possible to shorten the time required to reheat the heating bolt, thereby reducing the maintenance cost.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, . ≪ / RTI > Accordingly, such modifications are deemed to be within the scope of the present invention, and the scope of the present invention should be determined by the following claims.

100: Induction heating system for heating bolts
110: main body 120: power cable
130: Heating part 140: Heating bolt
150: core part

Claims (6)

A main body having a cooling water supply line connected to a power supply supplied from the outside and storing or branching the cooling water supplied from the water supply facility;
A heating bolt having a hollow circular pipe shape in which threads are formed on outer circumferential surfaces of both end portions to fasten the first binding portion and the second binding portion which are opposed to each other and the mounting hole is formed at the inner center along the longitudinal direction;
A heating bolt inserted in the installation hole along the longitudinal direction of the heating bolt and heating the heating bolt by induction heating through a power source supplied from the main body and heating the heating bolt to change the extension rate of the heating bolt And
And a core portion coupled to the inside of the heating portion to increase an output according to induction heating in a predetermined region of the heating portion,
Wherein the core portion is selectively detachably coupled by adjusting at least one of a size, a position, a number, or a coupling interval so as to partially control a temperature in one or a plurality of predetermined regions formed on the heating portion. Induction heating system for bolts. The method according to claim 1,
Wherein the core portion is formed of a material containing at least one selected from copper-zinc based ferrite, nickel-zinc based ferrite and manganese-zinc based ferrite. delete The method according to claim 1,
Further comprising an insulation part which is arranged to surround the outside of the heating part and simultaneously fixes the position of the core part while enclosing the core part at least in one or a plurality of predetermined areas formed on the heating part, Heating system. Claim 1:
A power cable provided between the body and the heating unit for connecting a power source to be supplied to the heating unit from the body,
Further comprising a connector provided at one end of the heating unit and connected to the power cable. The method of claim 5,
Further comprising a cooling unit for cooling the outside or inside of the power cable through the cooling water supplied from the cooling water supply line.

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