JPS647000Y2 - - Google Patents

Description

[Detailed description of the invention] This invention prevents abnormal discharge when a part of the tube material is discharge-expanded and fitted into the hole in the base material, and the vapor of the thin metal wire is released from the inner periphery of the tube material. This invention relates to a discharge tube expansion cartridge that does not adhere to surfaces.

When installing tubes integrally into holes formed in the base material, such as in a multi-tube cylindrical heat exchanger in which many heat transfer tubes are attached to a tube sheet, the degree of adhesion of the outer circumferential surface of the tube material to the inner circumferential surface of the hole is It may be important. In such cases, discharge tube expansion is sometimes used to tightly join the base material and the tube material. As shown in Figure 1, which shows the principle of conventional discharge tube expansion, the base material 1
Insert the pipe material 13 into the hole 12 formed in 1,
A discharge tube expansion cartridge 14 having a length approximately corresponding to the depth of the hole 12 is inserted into the tube material 13 at a position corresponding to the hole 12. A cylindrical cartridge body 15 made of a synthetic resin or the like that can expand and contract in the radial direction is filled with a liquid 16 such as water serving as a pressure medium, and is stopped at one end of the cartridge body 15 via a presser ring 17. The liquid 16 is sealed within the cartridge body 15 by the thin film 18 . At the center of the cartridge body 15 is a power supply electrode 19 and a return electrode 2 attached to the other end of the cartridge body 15.
A thin metal wire 21 is disposed with both ends connected to the power supply electrode 19 and the return electrode 20.
is connected. Further, the return electrode 20 protruding into the cartridge body 15 in parallel with the thin metal wire 21 is
It is fixed in the cartridge main body 15 through a plurality of thin plate-shaped brackets 25 together with the thin metal wire 21, and is electrically connected between the two open/close switches 22 and 23 through a capacitor 26.

Therefore, after opening the on-off switch 22 and closing the on-off switch 23 to charge the capacitor 26, when the on-off switch 22 is closed, a large current flows from the power supply electrode 19 to the thin metal wire 21, and the thin metal wire 21 is instantly melted and vaporized. At the same time, a portion of the liquid 16 also vaporizes and expands explosively. For this reason, the pressure responsible for expansion is transferred from the liquid 16 to the cartridge body 15.
acts radially on the tube 13 through the tube 1
3 is expanded and tightly integrated into the hole 12 of the base material 11.

By the way, if the base material 11 is grounded for safety, all the current from the thin metal wire 21 will not flow to the return electrode 20, and some or most of it will be connected to the thin film 18.
Sparks pierce through the inner circumferential surface 27 of the tube 13 at one end of the cartridge body 15, and this tube 13
Abnormal discharge that damages the inner circumferential surface 27 of the battery often occurs, and improvements have been sought.

The present invention has been made in view of such demands, and an object of the present invention is to provide a discharge tube expansion cartridge that prevents abnormal discharge and prevents the vapor of the thin metal wire from adhering to the inner circumferential surface of the tube material.

The structure of the cartridge for discharge tube expansion of the present invention that achieves this purpose is that it is filled with a liquid serving as a pressure medium and is inserted into a tube material inserted into a hole formed in a base material, and elastically expands and contracts in the radial direction. A thin metal wire wired at the center of the cartridge body and connected at both ends to a power supply electrode and a return electrode connected to a power source, and the pressure accompanying the vaporization of the thin metal wire is In a cartridge for discharge tube expansion, in which a pressure medium is transmitted to the tube material through the cartridge main body, and the tube material is expanded and brought into close contact with the hole,
The cartridge main body is made long so that the end of the cartridge main body on the side opposite to the side to which the power supply electrode is attached protrudes beyond the end face of the base material in which the hole is formed, and the end face of the base material The thin metal wire is made short so that the end of the thin metal wire on the side opposite to the side to which the power supply electrode is attached is away from the end of the thin metal wire.

Hereinafter, one embodiment of the discharge tube expansion cartridge according to the present invention will be explained in detail with reference to FIG. 2, which shows its working principle. Specific explanations will be omitted using the same reference numerals. Cartridge body 15 with thin film 18 attached by presser ring 17
One end of the cartridge body 15 is arranged so that it protrudes by l beyond the end surface of the base material 11 in which the hole 12 is formed.
is set longer than the conventional one, and the thin metal wire 21 is short so that the distance δ between the end face of the base material 11 and one end of the thin metal wire 21 is also larger than that of the conventional one (see Fig. 1). is set to . In other words,
In the present invention, one end of the cartridge body 15 protrudes by an amount l from the end surface of the base material 11 having the hole 12, and the distance δ from one end of the thin metal wire 21 to the end surface of the base material 11 is set larger than that of the conventional one. It is characterized by the fact that it is completely different from the conventional one. If the interval δ is set large here,
When the thin metal wire 21 vaporizes, the vapor breaks through the liquid 16 and becomes difficult to adhere to the inner circumferential surface 27 of the tube material 13, and even if it does break through, it will not adhere to the cartridge body 1.
5 protrudes by l, the protruding portion only adheres to the inner circumferential surface 28 of the cartridge body 15. Therefore, since there is a distance of l+δ between one end of the thin metal wire 21 and the inner circumferential surface 27 of the tube material 13, there is sufficient resistance to the current flowing through the thin metal wire 21, thereby preventing abnormal discharge such as sparks. It can be prevented.
The values of l and δ differ depending on the conditions, but values of 4 cm and 2 cm can be adopted, respectively.The value of l may be slightly longer, but if the value of δ is set to a large value, it will be perfect. The expanded portion of the pipe enters inside the hole 12 rather than the end surface of the base material 11, and the length of the portion where the inner circumferential surface of the hole 12 and the outer circumferential surface of the tube material 13 are in close contact with each other becomes short, which is undesirable. However, by adjusting the filling amount of the liquid 16, the tube material 1
It is possible to increase the close contact portion by somewhat shortening the length of the incomplete tube expansion portion 3.

As described above, according to the discharge tube expansion cartridge of the present invention, the thin metal wire is made short and the cartridge body is made long so that the metal vapor accompanying the vaporization of the thin metal wire does not adhere to the inner peripheral surface of the tube material.
It has become possible to perform high-quality pipe expansion work without the occurrence of abnormal discharges such as sparks.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing a tube expansion operation state using a conventional discharge tube expansion cartridge, and FIG. 2 is a principle diagram showing a tube expansion operation condition of an embodiment of the discharge tube expansion cartridge according to the present invention. In the symbols, 11 is the base material, 12 is the hole, 13 is the tube material, 14 is the discharge tube expansion cartridge, 15 is the cartridge body, 16 is the liquid, 19 is the power supply electrode, 20 is the return electrode, 21 is the thin metal wire, and 27 is the tube material. inner peripheral surface of, 28
is the inner peripheral surface of the cartridge body, l is the protrusion length from the end surface of the base material to one end of the cartridge body, and δ is the distance between the end surface of the base material and the thin metal wire.

Claims (1)

[Scope of utility model registration request] A cylindrical cartridge body that is filled with a liquid serving as a pressure medium and that is inserted into a tube inserted into a hole formed in a base material and that can elastically expand and contract in the radial direction; and a thin metal wire connected at both ends to a power supply electrode connected to a power source and a return electrode, and transmits pressure accompanying vaporization of the thin metal wire from the pressure medium to the tube material via the cartridge body, and In the cartridge for discharge tube expansion, the end of the cartridge body is located on the side opposite to the side to which the power supply electrode is attached than the end surface of the base material in which the hole is formed. This cartridge body is made long so that it protrudes,
Furthermore, the discharge tube expanding cartridge is characterized in that the thin metal wire is made short so that the end of the thin metal wire on the side opposite to the side to which the power supply electrode is attached is further away from the end surface of the base material.