JPS62290518A - Blockading of through hole of resin tube provided with axial through hole in tube wall in parallel - Google Patents

Abstract

PURPOSE:To blockade a through hole perfectly and permit the securing of sealing property for a long period of time, by a method, wherein the end of a tube is pinched between an inner mold and an outer mold, which form an annular gap at the end of the tube in a condition that the end of the tube is expanded or contracted, and high-frequency electric current is impressed between the inner mold and the outer mold or between inner or outer mold and a push ring while pushing them by the pushing ring. CONSTITUTION:A resin tube 1, whose tube end is heated and softened in a hot air furnace, is fitted into an inner mold 21 under a condition that a push ring 3 is retreated and the tube end is pushed against the slanted part of the inner mold 21 to expand it. In this case, the tube end is forced into the inner mold 21 so as to pass the slanted part and position in an annular gap 23. Subsequently, the resin tube 1 is pinched by an outer mold 22 and the inner mold 21. Thereafter, high-frequency electric current is impressed on electrodes 24, 25 to weld the inner wall and the outer wall of the tube by fusion while pushing the push ring 3 against the end of the resin tube 1 by a hydraulic cylinder 32. The tube end may be contracted instead of expanding and, in this case, the resin tube 1 is forced into the inner mold, provided with a slanted contracting section, and is pushed by split outer molds.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for closing holes in a resin tube in which holes are arranged in parallel in the tube axis direction in the tube wall.

(Prior art and its disadvantages) For example, by arranging a large number of through holes 13 in the tube axis direction in the tube wall of a resin tube l as shown in FIG. 5, the amount of raw materials used can be reduced and the tube can be made lighter. At the same time, attempts are being made to improve the strength against flat loads of pipes using the same amount of raw materials and to reduce deformation due to stresses such as earth pressure. Since such a resin pipe IFi has a characteristic of high flat rigidity, it is used, for example, as a buried pipe for sewage. The method for connecting the above resin pipes is to expand the inside diameter of one pipe and use it as a pipe socket, insert the end of the other pipe whose diameter does not expand into this, and connect with adhesive or a seal ring. is common.

However, with this connection method, the through hole 13 in the pipe wall communicates with the inside and outside of the pipe, and there is a risk that the fluid inside the pipe may leak or groundwater etc. may flow into the pipe, so it cannot be used as is. Can not do it. Therefore, such a resin'
! In case I, it is necessary to close the through holes 13 on the socket side and the insertion port side after extrusion molding or secondary processing.

Therefore, in Japanese Patent Publication No. 57-44111, as shown in FIG. /c Rotate the mold 15 in which the groove is formed, and mold this tube end into mold 1.
5, and then press K to twist the through-hole partition wall 14.
It has been proposed to close the through hole 13 by doing so. By twisting the tube ends in this way, the inner and outer walls 11 and 1
2 are pressed against each other to close the through hole 13. However, if you twist the part that has been subjected to such hole-blocking processing, it will cause problems. 11 and/or outside H
1i 2K< Because fins are formed, there is a risk that structural defects may occur and the tube may be damaged. Moreover, since the tube wall is simply crimped to crush the tube wall, the blockage cannot be sufficiently prevented.

The operation of rotating the mold 15 is also extremely complicated.

JP-A-54-103480 KFi, Figure 7 Ca
l and (bl VC, as shown, the through-hole partition 1 at the tube end
A method is disclosed in which the inner and outer parts 9111 and 12 are pressed together by cutting the inner and outer parts 9111 and 12 by cutting them using a cutting tool 16 while heating them, and then pressing them against a suppression mold 17. However, even with this method, the adhesion of the crushed portion cannot necessarily be said to be perfect. The work processes are many and complicated.

In this way, in both of the above two methods, since the through hole 13 is simply crushed by pressure, one through hole 13
There is a high risk that the blocked part will be surrounded by secondary processing such as socket processing after being blocked, shocks such as dropping, and changes over time. Further, in the case of a resin pipe made of vinyl chloride resin whose melting temperature and decomposition temperature are close to each other, it is necessary to control VcFi, heating temperature, and heating time, which is complicated.

On the other hand, there is a method of injecting a caulking material such as silicone resin into the through hole 13 to close it. However, injecting the caulking material into each hole individually is extremely complicated and causes variations in sealing performance for each hole. Moreover, silicone resin and vinyl chloride resin lack compatibility. the result,
A sufficient occluding effect cannot be achieved.

A method has also been proposed in which a blind plate made of an elastic material is crimped onto the tube H1 surface of the resin tube I. However, it may come off with a simple external force, so it cannot be said to be a complete 3-occlusion method.

(Problems to be Solved by the Invention) The present invention is intended to solve the above-mentioned conventional problems, and its purpose is to solve the problems of the prior art described above. The object of the present invention is to provide a method that can reliably close holes without decomposing the resin of the resin pipe. Another object of the present invention is to provide a method for closing a hole in a resin pipe that can ensure the sealing performance of the closed portion for a long period of time against stresses such as secondary processing such as socket processing, impact, and repeated compressive flattening loads. Then I'm very busy. Still another object of the present invention is to provide a method for closing a hole in a resin pipe, which is highly workable and economical.

Still another object of the present invention is to provide a method for closing a hole in a resin pipe, which allows for socket processing and the like to be performed at the same time as closing the hole.

(Means for Solving the Problems) In the hole closing method of the present invention, when a dielectric resin tube is placed under pressure inside a high-frequency electric field, each molecule causes rotational vibration due to the high-frequency electric field, and the distance between adjacent molecules increases. It uses high-frequency dielectric heating, which generates heat by causing dielectric loss due to friction.

That is, the through-hole closing method of the present invention involves forming an annular gap between an inner mold and an outer mold in which an annular gap is formed on the pipe end side with the end of the resin pipe expanded or contracted in diameter in an inclined manner. An inner mold that clamps the pipe end between an inner mold and an outer mold or that is formed by holding the pipe end in an annular gap and pressing the pipe end within the annular gap with a pressure ring. Alternatively, it is characterized by applying a high frequency current between the outer mold and the pressing ring.

(Function) In the uninvention, when the pipe end of the resin pipe is expanded or contracted in diameter in an inclined manner, an annular gap is formed between the inner mold and the outer mold in which an annular gap is formed on the pipe end side. Since the tube ends are held in the position between aK and the annular gap, the tube ends at the annular gap are inclined, and since the inclined tube ends are pressed by the pressure ring from the tube end side, the inner and outer walls at the tube ends are The force acts as if it were pressed in a diagonal direction, making it easier to press against the inner and outer walls. On the other hand, while pressing with a suppression ring, a high-frequency current is applied between the inner mold and the outer mold, or between the inner mold or the outer mold that pinches the tube end, and the press ring, so the tube end is particularly heated by high-frequency dielectric heating. The inner surfaces of the through-hole partition wall and inner and outer walls of the resin tube that are not in contact with the mold are melted and softened, and the inner and outer walls are pressed against each other, and the through-hole at the end of the tube is fused and closed.

(*Example) As shown in FIG. 1, the resin tube used in the present invention has a plurality of through holes 13 in the tube U along the tube axis direction. As the material for the resin tube 1, a thermoplastic resin that generates a large amount of heat during upper ε high-frequency dielectric heating is preferably used. For example, vinyl chloride resin, polyamide, or methacrylic resin. Among them, the soft vinyl chloride resin rapidly melts and softens even in a relatively low temperature range because its calorific value increases rapidly as the temperature rises. Therefore, the through hole 13 at the end of the resin pipe IFi made of soft vinyl chloride can be closed without performing a special preheating and softening process on the end of the resin pipe IFi. On the other hand, resin pipe 1 made of hard vinyl chloride resin, which has a lower calorific value than soft vinyl chloride resin, easily melts and softens close to its melting temperature, so if direct high-frequency dielectric heating is applied to the end of resin pipe 1, a through-hole will form. # for parts with small cross-sectional areas such as the distance H114! 11F
! 5. The concentrated force may burn the resin and cause it to decompose. Therefore, immediately before applying high-frequency dielectric heating, remove each resin tube made of hard vinyl chloride resin, and prepare a spare tube at the end of the resin tube 1 by, for example, contacting it with a hot plate containing a heater or placing it in a heating furnace. It is desirable to apply heat to ensure uniform heating. With K, the amount of heat generated can be increased, and high-frequency dielectric heating can be performed effectively. The preheating temperature depends on the material and shape of the resin pipe 1 used, but is appropriately set to a temperature in the range of Fi 100 to 150°C for the resin pipe 1 made of hard vinyl chloride resin, for example.

In particular, in the present invention, when expanding or contracting the diameter of the end of the resin pipe in an inclined manner, it is necessary to heat and soften the end of the VC#'i pipe. It is preferable to apply a high frequency current continuously while the condition is still cold.

The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1 is a side view, partially in section, showing one implementation of the method for closing a through hole in a resin pipe according to the present invention. In the figure, 1 is a resin pipe with through holes 13 arranged in the pipe axis direction in parallel on the pipe wall, 2a an inner mold 21 and an outer mold 2.
2 is a mold, a 3Fi annular pressing ring, and 4 is a high frequency generator.

The inner mold 21 has an intermediate pressure inclined portion, and is partially fixed to the fixing table 5 by a support 51. Outer mold 22Fi
It is divided into two parts at the axial dividing plane, and each part has an inner mold 2.
VC that can approach and depart from 11C! I'm being kicked. A gap is provided between the inner mold 21 and the outer mold 22 to hold the resin pipe 1, and when the outer mold 22 is brought close to the inner mold 21! A trap is made to hold the IC resin tube l. Also, between the inner mold 21 and the outer FM220! /cFi An annular gap 23 is formed on the tube end side of the resin tube 1 with the oval fat tube 1 held therebetween, and an annular pressing ring 3 is provided within this annular gap 23. This pressing ring 3 is connected to a fluid cylinder 32 via an arm 31.
It is connected to and can be inserted and retracted into the annular gap 23 by the action of the fluid cylinder 32. 24.2
5Fi are electrode materials provided on the inclined parts of the inner mold 21 and outer mold 22, and are made of highly conductive materials such as brass and copper.These electrodes are connected to the high frequency generator 4 through insulated conductive wires. It is connected. Electrode 24.25Fi inner mold 2
1 and the outer mold 22 are insulated with a light edge material.

The method for closing a hole according to the present invention will be explained using the above-mentioned device. First, as shown in FIG. 2, the outer mold 22 is removed from the inner mold 21, and with the suppression ring 2 retracted, a hard vinyl chloride resin pipe 1 whose tube end has been softened by heating in a hot air oven is inserted into the inner mold 21. The pipe end is pressed against the inclined part of the inner mold 21 to expand its diameter. At this time, the tube end is pushed over the inclined portion and positioned in the annular gap 23. Next, as shown in FIG. 3, outside IJ! 22 to approach the inner mold 21 and clamp the resin tube 1 therein. Thereafter, while pressing the press ring 3 toward the end of the resin tube l with the fluid cylinder 32, the electrode 2
4,251'l: Apply high frequency current. The frequency, electric field strength, application time, etc. of the high-frequency current to be used are determined as appropriate based on the material, shape, size, electrode spacing, etc. of the resin tube 1, but in the case of a resin tube made of hard vinyl chloride with a thickness of about 10 ff. Then, a high frequency current of 40 MHz may be applied to the power supply output 3 at 91 for 5 to 30 seconds. In addition, the pressing force by the pressing ring 3 is #12) l/cd or more [2 to 6
The range is preferably 1'41/cd.

In this way, l! of the inner mold 21 and the outer mold 22! The diameter-expanded end of the pipe clamped by the press ring 3 presses the inner wall of the pipe toward the outer wall of the pipe, and is heated and melted by the application of a high-frequency current, thereby welding the inner and outer walls.

Since the inner and outer wall surfaces of the tube end are in contact with the inner mold 21 and the outer mold 22, they do not melt, and the through-hole partition wall and the inner surfaces of the inner and outer walls are melted and fused to close the through hole. At this time, the pressed and displaced molten resin fills the through hole, thereby increasing the fused area and improving the closing strength of the through hole.

In the above example, the electrodes 24 and 25 are provided on the inner mold 21 and the outer mold 22, but the electrodes 24 may be provided on the suppression ring 3.

Also, instead of increasing the diameter of the tube end, it may be made to have a lfl diameter. At this time, to reduce the diameter of the tube end #i, the resin tube may be pushed into an inner mold provided with an inclined diameter reducing portion and pressed down with a half-split outer mold. Pull out the inner mold again! /c needs to be capable of expanding and contracting the diameter by forming a plurality of split molds in the axial direction at the large diameter portion.

In carrying out the hole closing method of the present invention, it is necessary not only to close the through hole at the end of the resin pipe 1, but also to perform socket processing or insertion processing that is necessary when piping the resin pipe 1. is efficient. Figure @4 shows an example of forming a rubber ring socket when connecting pipes using a rubber ring.

In Figure #J4, the same parts as in Figure 1 are given the same numbers.

The inner mold 21 has the same outer shape as the inner peripheral surface of the tube socket. A split mold 26 is provided in the middle of this inner mold 21, and this split mold 26
By engaging a conical loft 28 that can reciprocate in the axial direction with a conical space 27 provided at the center of the mold, the diameter of the split mold 26 can be expanded or contracted freely, forming an annular groove into which a rubber ring is fitted. It's like a trap. A rear VcFi sloped portion of the inner mold 21 and the outer mold 22 is formed, and electrodes 24 and 25 are provided at these positions.

Also in this device, the resin tube l is fitted into the inner mold 21,
The through hole at the end of the tube is welded and closed in the same manner as in the previous embodiment except that the rubber ring socket is formed.

(Effects of the Invention) The method for closing a hole in a resin pipe according to the present invention has the configuration described above, and the end of the resin pipe is expanded or contracted in diameter and is tilted, and then a pressure ring is applied from the end of the resin pipe. Since the pressure is applied, the inner and outer walls of the resin tube are pressed diagonally at the ends of the tube, which tends to cause the through hole to become clogged. The inner surface is melted, softened and fused, and the through hole is completely closed. Therefore, the sealing performance of the closed portion can be ensured for a long period of time against any stress such as secondary processing such as diameter expansion or repeated compressive flattening loads. Moreover, since it is easy to work with, it is economical. Furthermore, since high-frequency dielectric heating generates internal heat, no resin adheres to the mold surface at all. Since the through hole can be closed in a short time, there is no risk of disassembling the resin pipe. In addition, by using a socket processing mold as the inner mold of the mold, the through hole of the resin pipe can be closed and diameter expansion processing can be performed at the same time, which can further improve economical efficiency. By preheating the resin pipe, it can also be applied to hard vinyl chloride.

[Brief explanation of the drawing]

@ Figure 1 is a side view partially showing an embodiment of the through hole closing method of the present invention, Figure 2 is a sectional view partially omitting the first step of the embodiment in Figure 1; Figure 3 is a sectional view showing the next step from Figure 2, Figure 4 is a side view partially sectionally showing another embodiment of the present invention, and Figure 5 is a perspective view showing a resin pipe used in the present invention. , FIGS. 6 and 7 are cross-sectional views illustrating a conventional method for closing a hole. 1...Resin pipe, 11...Inner wall, 12...Outer wall, 1
3...Through hole, 14...Through hole partition, 2...Mold, 21
...inner mold, work 22...outer wall, 23...annular gap, 24.25...
Electrode material, 3... Annular pressing ring, 4... High frequency generator.

Claims (1)

[Claims] 1. A method of closing the through-hole opening at the end of a resin pipe in which a through-hole is provided in the pipe wall along the pipe axis direction, and the end of the resin pipe is expanded or contracted in diameter in an inclined manner. An annular pressure ring is used to hold the tube end in the annular gap between an inner mold and an outer mold, in which an annular gap is formed on the tube end side when the tube is in a radial state. This method is characterized by applying a high-frequency current between the inner mold and the outer mold or between the inner mold or the outer mold that pinches the tube end and a press ring while pressing the pipe in the axial direction of the pipe wall. A method for closing holes in a resin pipe with parallel holes.