JPH03252Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention uses a tube expansion cartridge inserted into each of a plurality of tube materials, and uses the energy discharged to the thin wires in the cartridge to sequentially expand the tube materials. This invention relates to a discharge tube expansion device that expands a tube and joins it to a tube sheet.

(Prior Art) FIG. 2 is a partial sectional view showing a conventional discharge tube expansion device. A tube expansion cartridge 18 is inserted into one end of a large number of tubes, for example, heat transfer tubes 28, inserted between two tube sheets 30. The tube expansion cartridge 18 is a cylindrical cartridge container 2.
Insulating tube expansion medium (mainly water is used)
22 is sealed, and a power supply piece 24 is attached to the central shaft portion.
A thin wire 26 held by a wire etc. is disposed and configured. One end of the thin wire 26 naturally hangs down to form a heat exchanger tube 28.
is in contact with. However, as described later, the thin line 26
Since a high voltage is applied to the heat exchanger tubes 28, there is no problem because the discharge occurs between the heat exchanger tubes 28 even if they do not necessarily come into contact with them.

The electric pulse generator 2, which is a power source, is connected to a DC power source 4.
, a capacitor 6 connected to it, and a switch 8 connected to it. One end of the capacitor 6 is connected to the high voltage conductor 1 via a switch 8.
0 to the discharge electrode 16, and the other end of the capacitor 6 is fixedly connected to a point on the tube plate 30 by a regression line 12.

The discharge electrode moving device 14 is controlled by a control means (not shown) to move the discharge electrode 16 vertically and horizontally on a plane parallel to the tube plate surface 31, thereby moving a large number of discharge electrodes 16. The tube expansion cartridges 18 are sequentially opposed to each other.

During discharge tube expansion, the discharge electrode 16 is opposed to a predetermined tube expansion cartridge 18, and the capacitor 6 is charged by the DC power source 4. The charging voltage at this time is, for example, a high voltage of 30 to 50 KV. Then, by closing switch 8, the energy stored in capacitor 6 is transferred to high voltage conductor 10-
Discharge electrode 16 - feeding piece 24 - thin wire 26 - heat exchanger tube 28 - tube plate 30 - thin wire 2 along the route of regression line 12
Discharge to 6. Note that the discharge electrode 16 and the power supply piece are electrically connected by gap discharge. The thin line 26 is
The discharge energy at this time instantaneously evaporates and vaporizes the tube expansion medium 22 around it, causing vaporization and expansion of the tube expansion medium 22. The heat transfer tubes 28 are expanded and joined to the tube plate 30 by the high pressure generated at this time. When the expansion of one heat exchanger tube 28 is completed, the discharge electrode 16 is moved to expand the other heat exchanger tubes 28 one after another.

(Problem to be solved by the invention) The large tube plate 30 has a diameter of 2 m, for example.
There are degrees. However, in the conventional discharge tube expansion device, when the tube plate 30 is large, discharge tube expansion is performed with the tube expansion cartridge 18 closest to the regression line 12, and conversely, discharge tube expansion is performed with the tube expansion cartridge 18 furthest away. In this case, the difference in inductance between the two electric (discharge) circuits cannot be ignored. Therefore, if the charging voltage of the capacitor 6 in the electric pulse generator 2 is kept constant, the magnitude and frequency of the discharge current will differ due to this difference in inductance, and as a result, if the tube expansion ability of the two differs, it will be difficult to There are some problems.

In this case, in order to control the discharge current to a predetermined value, it is necessary to adjust the charging voltage of the capacitor 6 in response to changes in the inductance of the electric (discharge) circuit. Various values are taken depending on the tube expansion position, and current control taking this into consideration is not easy.

Therefore, this invention aims to solve these problems.

(Means for Solving the Problems) Referring to FIG. 1, the discharge tube expansion device of this invention is provided at one end side of a tube material, for example, a heat exchanger tube 28, and a power source, for example, is provided in the tube expansion cartridge 18. A first moving device 32 for moving the discharge electrode 16 for supplying current from the electric pulse generator 2
, a second moving device 34 that is provided on the other end side of the heat exchanger tube 28 and moves a return conductor 36 for returning the current from the tube expansion cartridge 18 to the electric pulse generator 2; By controlling the moving devices 32 and 34 of No. 2, the discharge electrode 16 and the return conductor 36 are sequentially moved in correspondence with the predetermined heat transfer tubes 28, and the discharge electrode 16 and the return conductor 36 are respectively positioned at predetermined positions. A control device 38 is provided to control the operation.

The return conductor 36 is connected to the electric pulse generator 2 by the return line 12, for example, the heat exchanger tube 2
It has a cylindrical shape such that the tip contacts the tube plate 30 when it is placed over the end of the tube plate 8.

(Operation) The first moving device 32 is controlled by the control device 38 to sequentially move the discharge electrodes 16 to predetermined positions. For example, by moving the discharge electrode 16 on a plane parallel to one tube plate surface 31 and on an axis perpendicular to this plane, an appropriate gap is created between the discharge electrode 16 and the tip of the power supply piece 24 of the tube expansion cartridge 18. Have them hold it and approach them one by one. The second moving device 34 is controlled by the control device 38 to sequentially move the return conductor 36 to a predetermined position in response to the movement of the discharge electrode 16. For example, by moving the return conductor 36 on a plane parallel to the other tube plate surface 31 and on an axis perpendicular to this plane, the return conductor 36 is placed at the other end of the heat exchanger tube 28 facing the discharge electrode 16. Cover it and press its tip against the tube sheet 30.

The energy stored in the capacitor 6 in the electric pulse generator 2 is reduced by closing the switch 8.
High voltage conductor 10 - discharge electrode 16 - power supply piece 24 -
Thin wire 26 - heat exchanger tube 28 - tube sheet 30 - return conductor 36
- is discharged at the route of the regression line 12 into the thin line 26;
Therefore, regardless of the size of the tube plate 30, the inductance of the electric (discharge) circuit remains constant even when the tube expansion cartridge 16 is set in any position to perform the tube expansion process.

(Example) FIG. 3 is a front view schematically showing an example of the first moving device, and FIG. 4 is a partial side view thereof.
The first moving device 32 includes an X-axis drive mechanism 322 and a Y-axis drive mechanism 322 .
An axis drive mechanism 324 and a Z-axis drive mechanism 326 are provided. The Z-axis drive mechanism 326 includes a stepping motor and a ball screw, and thereby moves the discharge electrode 16 up and down on a plane parallel to the tube plate surface 31. The Y-axis drive mechanism 324 also includes a stepping motor and a ball screw, and thereby moves the discharge electrode 16 left and right on a plane parallel to the tube plate surface 31. The X-axis drive mechanism 322 includes an air cylinder, and thereby the discharge electrode 16
is moved back and forth on an axis perpendicular to the tube plate surface 31.
In addition, the code|symbol 34 is a holder for fixing a tube plate.

The second moving device 34 provided at the other end of the heat exchanger tube 28 may also be a device similar to the first moving device 32 described above. In this case, a return conductor 36 is attached to the tip of the X-axis drive mechanism 322 instead of the discharge electrode 16.

FIG. 5 is a block diagram showing an example of a control device. The control device 38 includes a positioning control section 382
and a Y-axis stepping driver 384 and a Z-axis stepping driver 386 for the first moving device 32. The first moving device 32 described above
The X-axis drive mechanism 322 includes an X-axis solenoid valve 222 and an air cylinder 224, and the Y-axis drive mechanism 324 includes a stepping motor 242, a ball screw 244, and position sensors 246, 248, 25.
The Z-axis drive mechanism 326 also includes a stepping motor 262, a ball screw 264, and position sensors 266, 268, and 270.

The controller 38 further includes a Y-axis stepping driver 385 and a Z-axis stepping driver 385 for the second moving device 34.
The positioning control unit 382 and these stepping drivers 385, 387 are provided with an axis stepping driver 387, and the positioning control unit 382 and these stepping drivers 385, 387 respectively have an Mechanism 346 is connected. These drive mechanisms 342, 344, 346
are similar to the drive mechanisms 322, 324, and 326 of the first moving device 32 described above, respectively. Note that the positioning control section 382 is connected to the sequence control device 40.

The positioning control unit 382 has a built-in microcomputer, and a positioning pattern PI indicating the order in which to expand the large number of heat transfer tubes 28, that is, how to position the discharge electrodes 16 and the return conductors 36, is input in advance. ing. The sequence control device 40 outputs a movement command signal S1. Upon receiving this signal S1, the positioning control unit 382 generates a Y-axis movement pulse S4 according to the positioning pattern PI.
and Z-axis movement pulse S5, and in response, drivers 384 and 386 output Y-axis drive output S6 and Z-axis drive output S7, respectively. In response, stepping motors 242 and 262 drive respective ball screws 244 and 264. Y-axis drive mechanism 32 at this time
4 and Z-axis drive mechanism 326 are determined by their respective position sensors 246, 248, 250 and 26.
It is fed back by Y-axis sensor output S8 and Z-axis sensor output S9 from 6,268,270. When the positioning of the discharge electrode 16 on the Y-axis and the Z-axis is completed as described above, the positioning control section 382 outputs the X-axis movement signal S3. In response to this, the X-axis solenoid valve 222 operates,
Compressed air A1 is applied to the air cylinder 224, and the discharge electrode 16 is positioned on the X-axis. As described above, the discharge electrode 16 is brought close to the tip of the power supply piece 24 of a predetermined tube expansion cartridge 18 with an appropriate gap.

At this time, in the same manner as above, the second moving device 3
4 is also controlled, and the heat exchanger tube 2 with the discharge electrode 16 facing
A return conductor 36 is placed over the other end of the tube 8, and its tip is pressed against the tube sheet 30.

When the positioning of the discharge electrode 16 and the return conductor 36 is completed, the positioning control section 382 outputs a movement completion signal S2. In response, the sequence control device 40 obtains a charge completion signal for the capacitor 6 in the electric pulse generator 2 and the movement completion signal,
Outputs a signal to close switch 8 and closes switch 8.
is closed to allow discharge tube expansion, and then the next positioning control is performed.

By repeating the above control,
Expansion of a large number of heat exchanger tubes 28 is performed sequentially.

In addition, in the above description, the first moving device 3
2, the discharge electrode 16 is arranged along the three axes of the X axis, Y axis, and Z axis.
Although the explanation has been given using an example in which the discharge electrode 16 can be moved in the axial direction, if the gap between the discharge electrode 16 and the power supply piece 24 of the tube expansion cartridge 18 is within a predetermined range, the X-axis The movement in the direction may be omitted. In addition, the second moving device 34
Although the description has been given using an example in which the return conductor 36 can be moved in three axial directions, if the return conductor 36 is provided with a notch through which the heat exchanger tube 28 can pass,
The movement in the X-axis direction may be omitted.

Furthermore, by replacing the discharge electrode 16 and the return conductor 36 and also reconnecting the high-voltage conductor 10 and the return line 12, it is possible to easily expand the opposite side of the heat transfer tube 28, thereby improving work efficiency. improves.

(Effects of the invention) According to this invention, regardless of the size of the tube plate, even if the tube expansion cartridge is set in any position, the electricity (discharge)
The inductance of the circuit remains constant. Therefore, simply by controlling the charging voltage of the capacitor to be constant, the value of the discharge current becomes constant, and variations in tube expansion caused by differences in discharge current can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing the discharge tube expansion device of this invention. FIG. 2 is a partial sectional view showing a conventional discharge tube expansion device. FIG. 3 is a front view schematically showing an example of the first moving device, and FIG. 4 is a partial side view thereof. FIG. 5 is a block diagram showing an example of a control device. 2... Electric pulse generator, 16... Discharge electrode,
18... tube expansion cartridge, 28... heat exchanger tube,
30... Tube plate, 32... First moving device, 34...
...Second moving device, 36... Return conductor, 38...
Control device.

Claims (1)

[Scope of Claim for Utility Model Registration] A discharge tube expansion device that sequentially expands tube materials using tube expansion cartridges inserted into a plurality of tube materials, which is provided at one end of the tube materials, A first moving device for moving a discharge electrode for supplying current from a power source; and a second moving device for moving a return conductor provided at the other end of the tube material for returning current from the tube expansion cartridge to the power source. By controlling the moving device and the first and second moving devices, the discharge electrode and the return conductor are sequentially moved in correspondence with predetermined pipe materials, and the discharge electrode and the return conductor are respectively positioned at predetermined positions. A discharge tube expansion device comprising a control device for controlling the discharge tube.