JP4025964B2 - Member expansion / contraction device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used when replacing various members attached to a predetermined fixing member by tube expansion, diameter expansion or caulking, such as a tube constituting a boiler, a heat exchanger, a condenser, or the like. The present invention relates to a member expansion / contraction device.
[0002]
[Prior art]
When replacing a tube that constitutes a boiler, heat exchanger, condenser, etc., it is necessary to pull out the existing tube from the fixed member, but the tube expands and contracts by heating and rapidly cooling the tube that is the member to be removed. Techniques have been developed that use the phenomenon to extract from the fixed member.
[0003]
In such a sampling operation, a high-frequency induction heating method or a gas combustion heating method is generally used as a means for heating the member to be extracted. The high frequency induction heating method is a method in which the extraction target member itself is heated by an eddy current generated in the extraction target member when a current is supplied to the induction heating coil disposed in proximity to the extraction target member. The gas combustion heating method is a method in which the temperature of the extraction target member is increased by rolling the extraction target member with a gas combustion flame such as a gas burner.
[0004]
[Problems to be solved by the invention]
In the high-frequency induction heating method, a magnetic flux is generated by a high-frequency current flowing in the heating coil, and an eddy current is generated in the extraction target member by this magnetic flux, so that the extraction target member generates heat. When the interval is long, the influence of the magnetic flux is weakened, and the eddy current generated in the member to be extracted tends to be smaller than the high-frequency current supplied to the heating coil, resulting in poor current efficiency.
[0005]
In addition, when the member to be extracted is a non-magnetic material, the degree of coupling by magnetic flux becomes low, heating becomes difficult, and inner surface heating requires about three times the output as compared with normal outer surface heating. Furthermore, in the case of the high-frequency induction heating method, it becomes difficult to secure the coil cooling water flow path when the heating output increases.
[0006]
On the other hand, in the case of the gas combustion heating method, it is excellent in that the heating work can be performed with simple equipment, but not only the heating work requires a high degree of skill but also the temperature management is difficult, and the member to be extracted The temperature distribution may become non-uniform or it may heat up to unnecessary parts.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a member expansion / contraction device that can heat and cool a member to be extracted in a relatively short time while maintaining high current efficiency.
[0008]
[Means for Solving the Problems]
When a high-frequency current is passed through one conductor, the current flows in a concentrated manner on the outer periphery of the conductor due to the skin effect. However, as shown in FIG. Thus, when a reciprocating circuit is formed and a high-frequency current is passed from the power supply device 61 to the conductor 60, the current flows in a concentrated manner in portions where the conductors 60 face each other due to the proximity effect which is a kind of skin effect. That is, as shown in FIGS. 5A and 5B, a current concentration portion 62 is generated at a portion where the conductors 60 face each other. In this case, there is a property that the current concentration increases as the distance between the opposing portions is smaller and the frequency of the high-frequency current is higher.
[0009]
The member expansion / contraction device according to the present invention applies such properties peculiar to a high-frequency current to heat and expand the extraction target member, and then cools and contracts the extraction target member using a fluid. The member expansion / contraction device includes a conductor that can be disposed in an insulating state in proximity to a member to be extracted having conductivity, a conductive member that partially conducts the conductor and the member to be extracted, the conductor, A power supply device that supplies a high-frequency current to an electrical circuit formed by a conducting member and the extraction target member, and a fluid supply unit that supplies a fluid for cooling the extraction target member are provided.
[0010]
With respect to a member to be extracted, such as a tubular body, which is attached by restricting the outer peripheral portion or the like with a predetermined fixing member, the conductor is kept in an insulated state, and the conductor and the member to be extracted are placed through a conductive member. When a high frequency current is supplied from a power supply device to an electric circuit that is partially conductive and is formed of the conductor, the conductive member, and the member to be extracted, the high frequency current flows through the electric circuit. At this time, the proximity effect described above occurs, and high-frequency current flows in a concentrated portion in the vicinity of the conductor in the extraction target member, so that the proximity portion rapidly generates heat due to Joule heat, and the heat extraction target member The whole rises in temperature and expands. When the extraction target member is heated to an appropriate temperature, the power supply is stopped, and when the fluid is supplied from the cooling fluid supply means to cool the extraction target member, the extraction target member contracts rapidly. It is released from the restraint and can be easily removed.
[0011]
In this way, since the high frequency current is directly applied to the member to be extracted to generate heat, the member to be extracted can be heated and expanded in a short time, and there is no coupling loss that is unavoidable in the high frequency induction heating method, so that the current efficiency Is also expensive. Further, due to the proximity effect of the high-frequency current, the high-frequency current flows intensively in the vicinity of the part to be extracted and the conductor, so that the necessary part can be heated in a concentrated manner. Furthermore, by changing the location of the conductor or the location of the conductive member, the portion where the high-frequency current is concentrated can be increased or decreased, and excessive current can be prevented.
[0012]
In addition, since the conductor arranged close to the extraction target member is kept in an insulated state with respect to the extraction target member, a high-frequency current flows between the conductor and the extraction target member at a position other than the conduction member. The current concentration state does not fluctuate.
[0013]
Here, it is desirable to use a power supply device that can supply a high-frequency current having a frequency of 1 kHz to 90 kHz. As described above, the proximity effect of the high-frequency current becomes more prominent as the frequency of the high-frequency current is higher, and the concentration of the current tends to increase. Therefore, by supplying a high-frequency current having a frequency of 1 kHz to 90 kHz, the member to be extracted is necessary. It becomes possible to heat the portion intensively in a short time, and the current efficiency is also good.
[0014]
In this case, the appropriate frequency of the high-frequency current is preferably set according to the magnitude of the current loss in the cable that electrically connects the power supply device and the conductor or the required proximity effect. In this case, the proximity effect tends to become more prominent as the cable loss is larger and the frequency is larger, and the part to be actually heated is the entire extraction target member. Must be set.
[0015]
When the frequency of the high-frequency current to be supplied is less than 1 kHz, the proximity effect is reduced, and the current flows through the entire member to be extracted, so that a large current is required and the cable loss tends to increase. Yes, when the frequency is higher than 90 kHz, the proximity effect becomes prominent, and the proximity of the extraction target member to the conductor tends to be high temperature, which may cause overheating.
[0016]
On the other hand, the voltage of the high-frequency current to be supplied is preferably about 10V to 60V. In this case, the appropriate voltage is set according to various conditions such as safety to the human body, cable length, and cable cost. In addition, when the voltage of the high-frequency current to be supplied is smaller than 10V, a large current for supplying electric power necessary for heating is required. Therefore, when the cable diameter is larger than 60V due to an increase in the cable diameter, There is a risk of electric shock due to contact or electric leakage.
[0017]
On the other hand, as the cooling fluid supply means, by providing a fluid discharge nozzle capable of discharging the cooling fluid to the extraction target member, it is relatively easy to supply and discharge the cooling fluid to the fluid discharge nozzle. With a simple operation, it becomes possible to rapidly cool and shrink the member to be extracted at a high temperature, thereby improving workability. In addition to water and other liquids, air and non-flammable gases are suitable as the cooling fluid. However, water and other liquids are superior in that they have a high cooling capacity because of their relatively high specific heat. Air and incombustible gas are superior in that they do not wet the member to be extracted and are discharged into the atmosphere after protruding, so that no drainage equipment is required.
[0018]
In addition, when an expandable / contractible locking device for removably locking the conducting member to the extraction target member is provided, the conductive material with respect to the extraction target member such as a tubular body can be expanded and contracted. Therefore, it is possible to easily perform the close placement work and the withdrawal work in a short time, so that the work efficiency can be improved and the construction period can be shortened.
[0019]
The expansion / contraction locking device preferably has a function of extending and contracting in a radial direction around a predetermined support member. For example, when the extraction target member is a tubular body, it is formed of a material having a spring property. By inserting a slit of 6 to 8 into the cylindrical body, a conical pressure expanding tool is movably disposed in the axial direction, and the pressing diameter expanding tool is moved in the axial direction. A mechanism for causing the cylindrical body to radially expand and contract radially to contact and release the inner peripheral surface of the extraction target member is suitable. When the extraction target member is a square tube, the cylindrical body having the slit is preferable. Further, a mechanism in which pyramid-shaped pressure expanding tools are similarly arranged is suitable.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a partial cross-sectional view showing a state in which a member expansion / contraction device according to a first embodiment of the present invention is arranged on a member to be extracted, and FIG. 2 is a partial enlarged view of the member expansion / contraction device shown in FIG.
[0021]
As shown in FIG. 1, a member expansion / contraction device 1 according to this embodiment includes an electrically conductive circular tubular member 4 that is attached to a through hole 3 formed in a fixing member 2 by mechanical joining. The first conductor 5 that is close to the peripheral surface and is disposed in an insulated state, the second conductor 6 that is disposed in the vicinity of the opening of the extraction target member 4, and a plurality of different positions of the extraction target member 4 The first conductive member 7 and the second conductive member 8 that partially conduct the first conductive member 5 and the second conductive member 6 and the extraction target member 4, the first conductive member 5, the first conductive member 7, and the extraction target A power supply device 9 that supplies a high-frequency current to an electric circuit formed by the member 4, the second conductive member 8, and the second conductor 6, and a fluid that is a fluid supply unit that supplies a fluid for rapidly cooling the extraction target member 4 Supply source 10, fluid transfer hose 11 and fluid discharge nozzle 1 It is equipped with a door. The power supply device 9 is connected to a commercial power supply 13 by a power cable 14.
[0022]
After the member expansion / contraction device 1 is set as shown in FIG. 1, when a high frequency current is supplied from the power supply device 9, the first conductor 5 constituting the electric circuit is in the closest state of the extraction target member 4. The proximity effect described above occurs in the inner peripheral portion 4a, and high-frequency current flows in a concentrated manner in the inner peripheral portion 4a of the member 4 to be extracted. Therefore, the inner peripheral portion 4a rapidly generates heat due to Joule heat, and the heat is extracted. The entire target member 4 is heated and thermally expanded.
[0023]
When the extraction target member 4 is heated to an appropriate temperature, the power supply from the power supply device 9 is stopped, and the cooling fluid supplied from the fluid supply source 10 is discharged from the fluid discharge nozzle 12 to the extraction target member 4 and extracted. If the target member 4 is cooled rapidly, the extraction target member 4 rapidly contracts to form a gap between the fixing member 2 and the through hole 3, and is released from the restraint of the fixing member 2. It can be easily extracted from the through hole 3.
[0024]
As described above, since the high frequency current supplied from the power supply device 9 is directly supplied to the extraction target member 4 to generate heat, the extraction target member 4 can be heated and expanded in a short time. The current efficiency is high because there is no coupling loss. In addition, due to the proximity effect of the high-frequency current, the high-frequency current flows in a concentrated manner in the vicinity of the extraction target member 4 and the first conductor 5, so that a necessary portion can be concentratedly heated. Furthermore, the increase / decrease of the part which concentrates a high frequency current is changed by changing the arrangement place of the 1st conductor 5 and the 2nd conductor 6 with respect to the extraction object member 4, or the installation place of the 1st conduction member 7 and the 2nd conduction member 8. The change can be made and an excessive current can be prevented.
[0025]
Moreover, since the 1st conductor 5 arrange | positioned with respect to the extraction object member 4 and the 2nd conductor 6 arrange | positioned in the vicinity of the opening part of the extraction object member 4 are all maintained with the extraction object member 4, A high-frequency current flows between the first conductor 5 and the second conductor 6 and the extraction target member 4 at a position other than the first conducting member 7 and the second conducting member 8, or the current concentration state fluctuates. Since there is nothing, stable work can be secured. Since the first conductor 5 and the second conductor 6 may be copper plates or rods that efficiently conduct high-frequency current, the heating coil having a complicated structure used in the conventional high-frequency induction heating method. Is unnecessary.
[0026]
On the other hand, the frequency of the high frequency current supplied by the power supply device 9 can be adjusted in the range of 1 kHz to 90 kHz, and the voltage can be adjusted in the range of 10 V to 60 V. In this embodiment, the frequency of the high frequency current is set to 20 kHz and the voltage is set to 30 V. As a result, the extraction target member 4 was able to generate heat in a short time. Further, in the present embodiment, when water having a relatively large specific heat is used as the cooling fluid discharged from the fluid discharge nozzle 12, the extraction target member 4 that has been heated and expanded can be rapidly cooled and rapidly contracted. In addition to liquids such as water, it is possible to use gases such as air and non-combustible gases as the cooling fluid, such as air (gas) for main cooling and water (liquid) for auxiliary cooling. A gas-liquid combined cooling system can also be employed.
[0027]
The means for detachably locking the first conducting member 7, the second conducting member 8, the fluid discharge nozzle 12, and the like to the inner peripheral portion 4a of the extraction target member 4 is not particularly limited. A cylindrical body formed of a material having a slit is divided into 6 to 8 axial slits, and a conical pressure expanding tool is movably disposed in the cylindrical body in the axial direction. By moving in the axial direction, it is possible to provide an expandable / contractible locking device having a mechanism for radially expanding and contracting the cylindrical body so as to contact and disengage the inner peripheral surface of the member 4 to be extracted. By using such a locking device, it is possible to easily perform the placement work and the withdrawal work of the first conductor 5 and the second conductor 6 with respect to the circular extraction target member 4 in a short time. It is possible to improve work efficiency and shorten the construction period.
[0028]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a partial cross-sectional view showing a state in which the member expansion / contraction device according to the second embodiment of the present invention is arranged on a member to be extracted, and FIG. 4 is a partial enlarged view of the member expansion / contraction device shown in FIG. 3 and 4, members having the same symbols as those shown in FIGS. 1 and 2 are members that exhibit the same functions and effects as the member expansion / contraction device 1 of the first embodiment. Is omitted.
[0029]
In the member expansion / contraction device 21 of the present embodiment, the first conductor 25 and the second conductor 26 are insulated from the extraction target member 24 fitted in the bottom of the bottomed hole 23 formed in the fixing member 22. The first conductor 25 and the second conductor 26 and the peripheral portion of the extraction target member 24 are partially conducted via the first conducting member 27 and the second conducting member 28. An air nozzle 32 that discharges cooling air is disposed above the extraction target member 24, and an air pump 30 and an air hose 31 for supplying air to the air nozzle 32 are provided. , A fixing means 29 that is a support means for locking the whole so as not to drop off, and has a function of expanding and reducing the diameter radially from the axis of the bottomed hole 23 by the cam mechanism. .
[0030]
After the member expansion / contraction device 21 is set as shown in FIG. 3, when a high frequency current is supplied from the power supply device 9, the first conductor 25 and the second conductor 26 are brought into the closest state as shown in FIG. In the upper surface portion 24a of the extraction target member 24, the proximity effect described above occurs, and high-frequency current flows in a concentrated manner on the upper surface portion 24a of the extraction target member 24. Therefore, the upper surface portion 24a rapidly generates heat due to Joule heat, The entire extraction target member 24 is heated by the heat and thermally expanded.
[0031]
When the extraction target member 24 is heated to an appropriate temperature, power supply from the power supply device 9 is stopped, and the air supplied from the air pump 30 is discharged from the air nozzle 32 to the extraction target member 24 to rapidly cool the extraction target member 24. For example, the extraction target member 24 rapidly contracts to form a gap between the bottomed hole 23 of the fixing member 22 and is released from the restraint of the fixing member 22, so that the extraction target member 24 is removed from the bottomed hole 23. Can be easily extracted.
[0032]
If the member expansion / contraction device 21 is used as described above, even the extraction target member 24 fitted into the bottomed hole 23 having a shape not penetrating the fixing member 22 can be easily extracted. Further, since the member expansion / contraction device 21 uses air as a cooling fluid for the extraction target member 24, the air discharged from the air nozzle 32 hits the extraction target member 24 and then from the opening of the bottomed hole 23. It is discharged into the atmosphere and does not accumulate in the bottomed hole 23, has excellent workability, and does not require drainage equipment that is required when the cooling liquid is discharged. The structure and function of other parts are the same as those of the member expansion / contraction device 1 of the first embodiment.
[0033]
【The invention's effect】
The present invention has the following effects.
[0034]
(1) A conductor that can be disposed in an insulated state in proximity to a member to be extracted having conductivity, a conductive member that partially conducts the conductor and the member to be extracted, the conductor, the conductive member, and While maintaining a high current efficiency by including a power supply device that supplies a high-frequency current to an electric circuit formed by the extraction target member and a fluid supply unit that supplies a fluid for cooling the extraction target member The member to be extracted can be heated and expanded and cooled and contracted in a relatively short time.
[0035]
(2) Since the power supply device can supply a high-frequency current having a frequency of 1 kHz to 90 kHz, a necessary portion of the member to be extracted can be intensively heated in a short time, and current efficiency is also improved.
[0036]
(3) By providing a fluid discharge nozzle capable of discharging a cooling fluid to the sampling target member as the fluid supply means, a relatively simple operation of supplying and discharging the cooling fluid to the fluid discharge nozzle Thus, it becomes possible to rapidly cool and shrink the member to be extracted at a high temperature, so that workability is improved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing a state in which a member expansion / contraction device according to a first embodiment of the present invention is arranged on a member to be extracted.
FIG. 2 is a partially enlarged view of the member expansion / contraction device shown in FIG.
FIG. 3 is a partial cross-sectional view showing a state in which a member expansion / contraction device according to a second embodiment of the present invention is arranged on a member to be extracted.
FIG. 4 is a partially enlarged view of the member expansion / contraction device shown in FIG.
5A and 5B are diagrams showing a proximity effect of a high-frequency current, where FIG. 5A is a plan view of a U-shaped conductor, and FIG. 5B is a front view of the U-shaped conductor.
[Explanation of symbols]
1,21 Member expansion / contraction device 2,22 Fixing member 3 Through hole 4,24 Extraction target member 4a Inner peripheral portion 5,25 First conductor 6,26 Second conductor 7,27 First conduction member 8,28 First 2 conduction member 9 power supply device 10 fluid supply source 11 fluid transport hose 12 fluid discharge nozzle 13 commercial power source 14 power cable 23 bottomed hole 24a upper surface portion 29 fixing auxiliary tool 30 air pump 31 air hose 32 air nozzle

Claims (3)

First and second conductors, at least one of which is close to the extraction target member having conductivity and can be disposed in an insulated state with respect to the extraction target member, the first and second conductors, and the extraction target member First and second conducting members that conduct at two different locations on the same peripheral surface of the extraction target member, the first conductor, the first conduction member, the extraction target member, the second conduction member, and A power supply device for supplying a high-frequency current to an electric circuit formed of the second conductor; and a fluid supply means for supplying a fluid for cooling the extraction target member, wherein the high-frequency current flowing through the extraction target member and orientation, so that the direction of the current flowing through the conductor in proximity to the sampling target member of the first and second conductor are opposite to each other, in that a first and second conductor Member deflating device according to symptoms. The member expansion / contraction device according to claim 1, wherein the power supply device can supply a high-frequency current having a frequency of 1 kHz to 90 kHz. The member expansion / contraction device according to claim 1, wherein a fluid discharge nozzle capable of discharging a cooling fluid to the extraction target member is provided as the fluid supply unit.

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