JPS5835446B2 - Tube end connection method and flexible strip heat generating plate material for connection - Google Patents

Description

[Detailed Description of the Invention] Polyethylene pipes or polypropylene pipes have excellent chemical resistance, and various large and small diameter pipe materials are used for transportation piping, but since there is no suitable adhesive for connecting the pipe ends, butted pipes Various methods are used, such as attaching a shoulder collar to the outer circumferential surface of the end to lock the flange, or using a plastic joint tube with a nichrome wire wrapped around the inner surface in a half-embedded manner to perform electrical fusion welding. Although several methods have been introduced, none of them can be said to be practically satisfactory as they are cumbersome and costly to implement.

For example, an example of using a pipe joint in which the nichrome wire is wound in a coil along the inner circumference is shown in the reference diagram, where a and b are the polyethylene pipes to be connected, a' and b' are the ends of the iron pipe, C
is a nichrome wire, d' is a pipe joint obtained by winding the nichrome wire in a coil along the inner circumference of the tube, and g is a jig. Although this structure seems to be obtained, polyethylene pipes generally have large dimensional errors, so it is difficult to achieve complete fusion between the inner surface of the pipe fitting d' and the outer peripheral surface of the pipe ends of the pipes a and b inserted from both ends.
The formation of leaks is often unavoidable.

In particular, it is troublesome to install the nichrome wire C in a coiled form inside the pipe joint, and if the diameters of both pipes a and b are changed, not only does the size of the joint need to be changed, but it is also troublesome to use the jig g. Inevitable.

The method of the present invention has succeeded in solving these problems at once and easily forming an airtight fused structure.The gist of the method can be explained as follows with reference to drawings showing an example of its implementation. It is.

In the present invention, the first pipe refers to a pipe material 1 made of a plastic material such as a polyethylene pipe, a polypropylene pipe, a polyvinyl pipe (one end of which can be processed into a heat-shrinkable enlarged opening 1'a), 1' is the connecting end of the iron pipe, r is the connecting end 1
The expanded end obtained by forming the tube end port 1'a of ' into the expanded opening 1'a, f'b is the expanded opening wall of the expanded end, and fc is the inner surface of the expanded opening wall fb.

Further, in FIG. 3, d is the expansion cone angle of one end of the first tube, and R is the diameter of the expansion opening fa.

The second pipe is a mating pipe 2.2 that is connected to the first pipe, and is the connecting end of the second pipe, and the end 2 is inserted into the enlarged opening RA of the first pipe when connecting with the first pipe. inserted.

2'a is the tube end opening of the connection side end 2, 2'b is the four peripheral walls of the tube end, and 2'c is the outer surface of the tube end.

3 is a tube end fitting gap, which is particularly shown in FIG.
When one end 2' of the second pipe is inserted into the enlarged opening 1"a of the pipe, both sides formed between the four enlarged circumferential walls 1"b of the first pipe and the diurnal wall 2'b of one end of the second pipe are inserted. This is the fitting gap between the tube ends r and 2'.

4 is a rubber ring for backing, 5 is a heating element for connecting the tube ends, and it is preferable to use a rubber ring 4 made of silica rubber or other heat-resistant rubber. The core member 5a is made of plastic that can be fused to the core member 2, and the nichrome wire 5b is wrapped around the outer periphery of the core member. Both ends of the chrome wire serve as the power supply connection ends 5b', and are used by being fitted in a split ring shape around the outer periphery of one end of the second tube.

Core members of various shapes with different cross-sections are used.For example, core members with circular cross-sections can also be used, but a core member made of a strip material with a rectangular cross-section can be used most effectively. The heating element used as a member will be explained in detail.

The heating element 5 has a notch 5 on one or both longitudinal edges of a strip-shaped core member 5a made of a plastic material having the properties described above.
A large number of nichrome wires 5c' are provided in a spaced manner, and the nichrome wire 5b is passed through the cuts 5c' one after another and wound around the crest side surface of the strip-shaped core member 5a in contact with the nichrome wire 5b, and both ends of the nichrome wire are connected to a power source in the form of a drawer. 9 is an enlarged front view showing an example of the heating element 5, FIG. 10 is a partially enlarged perspective view of FIG. 9, and FIG. FIG. 5 is a perspective view showing a state in which the heating element 5 of FIG.

5c is the cut edge, 5c' is the cut, 5c// is the width of the cut, 5h is the depth, 5d is the end of the core member, and 1 is the length.

FIG. 12 shows a flexible heating plate material 6 of a length that is wound in a spiral shape, and the heating element 5 for connecting the tube end is used by cutting out a required length from the heating plate material 6 of the length of the wire. The power supply connection end 5b' of the cut out heating element 5 is secured by adjusting the length of the core member during cutting out.

Also, this long heating plate material 6 is different from the heating element 5 shown in FIGS. 9 to 11 only in length and in that it does not have a power supply connection end 5b', and the same reference numerals indicate the same parts.

Note that each core member 5a of the heating element 5 or the long heating plate material 6 is made of a plastic material that is heat-sealed to both the tubes 1 and 2 as described above.For example, when both tubes are made of polyethylene, polyethylene resin is used. When made of propylene, propylene resin is used, but if both pipes 1.2 are made of different plastic materials, the use may be determined experimentally as appropriate.

In carrying out the present invention, first, one end of the first tube 1'a is
is formed into a heat-shrinkable expanded opening 1''a by a conventional method, and then one end 2 of the second tube is inserted into the expanded opening 1''a, and the expanded end 1'' of the first tube and the second tube are inserted. A tube end fitting gap 3 is formed between the end 2', and the rubber ring 4 and the tube end connecting heating element 5 are placed at the connection side end 2 of the second tube, with the rubber ring 4 on the front side. The heating element 5 is disposed on the rear side and externally fitted, and the rubber ring 4 and the heating element 5 are thus inserted into the tube end fitting gap 3.

This insertion may be done by first pushing in the rubber ring 4 and then pushing in the heating element 5, but this can be done more efficiently if the heating element is inserted in a secant annular shape.

However, when pressing the latter, it is important that the cut edge 5c of the heating element 5 is in contact with the rubber ring 4, and this means that the rubber ring and the nichrome wire are in contact with the cut edge 5c.
This is to prevent heat damage to the rubber ring.

Therefore, when making the cut with the edge facing outward, care must be taken to keep the rubber ring and nichrome wire apart.

The effect obtained by the notches 3c' is of great significance, but furthermore, these many notches prevent the nichrome wire from tangling and coming off, so it greatly contributes to the work.

Next, if the nichrome wire 5b of the heating element 5 is energized to generate heat, the enlarged opening wall 1"b of the first tube will be opened by the enlarged opening 1"a.
At the same time, the rubber ring 4 is thermally shrunk and pressed together with the heating element 5 onto the insertion side outer surface 2'c of the second tube, and the rubber ring 4 and the secant annular heating element 5 are separated into two types 1"b and 2'b. The rubber ring 4 airtightly seals the fitting gap 3 between the tube ends, and the heating element 5 is fused 5' and q' to the two tubes 1.2 to firmly connect the two tubes 1.2. The fused heating element 5 is the rubber ring 4
Prevents the pipe from popping out due to pressure inside the pipe.

4 and 5 are enlarged views showing how the rubber ring 4 and the split line annular heating element 5 are inserted into the tube end fitting gap 3. FIG. The rubber ring is shown in a state before being inserted into the fitting gap 3, and FIG. 5 shows a state in which the rubber ring is elastically deformed and exhibits a sealing function after insertion.

FIG. 6 shows the cross-sectional structure of the connecting portion j obtained by energizing and heat shrinking after insertion.

The present invention can be easily implemented anywhere as long as it is a plastic pipe that can be heat-shrinked, even if it is a plastic pipe that does not have an adhesive, which is suitable for the enforcement of the provisional ordinance. This is useful because it provides a good connection.

Moreover, the spiral heating plate material 6 shown in FIG. The benefits obtained by the present invention are significant because the connecting operation can be carried out effectively without damaging the ring due to heat, as described above.

Example pipe material: The first pipe is outer diameter 210 x inner diameter 216 x length 1000 mm.
Polyethylene pipe rubber ring 4: Rubber rings shown in Figures 7 and 8 made of heat-resistant silicone rubber were used for both the first and second pipes.

Inner diameter of this ring r21c)u + cross section dφ6mm Heating element 5: A device constructed as shown in FIGS. 9 and 10 was used.

However, dimensions of the core member: Length L: 670 Thickness T: 5 mm Width W: 35 m Door cut 5c': 23 Width of this cut 5c//: 3 Depth 5h: 10 Material of the core member: Polyethylene core Resistance wire wound around the member: ordinary nichrome wire of φ0.8 mm Operation: One end of the first tube was formed into a heat-shrinkable enlarged opening 1"a with a cone angle of 35 degrees and a diameter of R236 mm by a conventional method, and the other end was At this point, a heat-resistant rubber ring 4 of the size described above is fitted loosely onto the connecting end 2 of the second pipe, and the heating element 5 is wound around the rear side of the ring in a secant annular shape as shown in Figure 11. Then, one end 2 of the second tube is inserted into the enlarged opening 1''a of the first tube to form a tube end fitting gap 3 as shown in FIG. The above-mentioned rubber ring 4 is pushed into the gap 3 as shown in FIG. When the nichrome wire is energized, the enlarged opening wall 1"b thermally contracts together with the enlarged opening 1"a, and the enlarged opening wall 1"b becomes the sixth
As shown in the figure, the rubber ring 4 and the heating element 5 are pressed onto the outer surface 2'c of the tube end of the second tube, and the rubber ring 4 is pressed onto the inner surface 1''C of the expanded opening wall and the outer surface of one end of the second tube. 2'c, and the core member 5a of the heating element 5 is elastically pressed between the two side surfaces 1''c, z
'c' and 'c' were fused 5' to form an airtight and strong connection structure.

At this time, the voltage was 70 V, the current was applied for 7 minutes, and the temperature of the outer surface of the connection part j after 7 minutes was about 100°C.

The joint j of the two pipes 1.2 thus obtained was subjected to a water pressure test of 10 kg/ffl for 10 minutes in the manner shown in Figure 13, but the joint j of the two pipes 1.2 was There was no separation and no water leakage was observed.

Supplementary note: Figure 13 is a route map showing the water pressure test procedure for the connection j obtained in this example, where 7 is a water supply pipe, 8 is a lower closing plate, 8a is a bolt nut, and 8b is a ring-shaped stopper. , 9 is an upper closing plate, 9a is a bolt nut, 9b is a ring-shaped stopper, 1
0 is a pressure gauge, 11 is a pump, 12 is a bypass, 13 is a water tank, ■ is an inlet valve of the pump, vl is an outlet valve, 7° is a bypass valve, v3 is a water supply valve, and v4 is a pressure relief valve.

[Brief Description of the Drawings] The drawings are explanatory diagrams of the method of the present invention. Figure 1 is a partially cutaway front view of both pipes to be connected, and Figure 2 is a partially cutaway diagram showing the state in which one end has been processed. 3 is a partially cutaway front view showing the fitting of both pipes, FIGS. 4 to 6 are partially cutaway enlarged front views illustrating the connection order, and FIG. 7 is shown in FIG. 4. 8 is a sectional view taken along the line A-A in FIG. 7, FIG. 9 is a front view of the heating element, FIG. 10 is a partially enlarged perspective view of FIG. 9, and FIG. FIG. 12 is an enlarged perspective view of a heating element formed in a secant annular shape, FIG. 12 is a plan view of the beam-length heating plate material for supplying the heating element shown in FIG. 9, and FIG. 13 is a route diagram showing procedures for a pressure test. Note that 1 is a plastic tube that can be heat-shrinked, 2 is any plastic tube, 3 is a tube end fitting gap, 4 is a rubber ring, 5 is a heating element, and 6 is a long heating plate material.

Claims (1)

[Claims] 1. A heat-shrinkable plastic pipe 1 is used as a first pipe, an arbitrary plastic pipe 2 is used as a second pipe, and when connecting one end of the second pipe to one end of the first pipe, One end of the first tube opening 1'a is formed into an enlarged opening f/a for heat absorption, and one end 2 of the second tube is inserted into the enlarged opening.
A tube end fitting gap 3 is formed between "b" and the peripheral wall 7b of the second tube, and a rubber ring 4 is externally fitted to the insertion end 2' of the second tube, and a rubber ring 4 is fitted on the rear side of the rubber ring. The following heating element 5 is wrapped around the second tube end 2 in a split annular shape and inserted into the tube end fitting gap 3 together with the rubber ring 4, and then the nichrome wire 5b of the heating element 5 is energized to generate heat. Due to the heat generation, the expanded diurnal wall fb is thermally contracted to the expanded opening, and the thermal contraction of the expanded diurnal wall presses both the rubber ring 4 and the heating element 5 onto the outer surface 7c of the insertion tube end 2. , type 2 fb with the same gap 3,
2'b, thus sealing the tube end fitting gap 3 with the rubber ring 4, and fixing the core member 5a of the heating element 5 to the above two types f.
A method for connecting the ends of the first pipe and the second pipe, characterized in that the ends of the first pipe and the second pipe are fused 5' and 2'b. A tube in which a core member 5a is made of a plastic material that can be heated and fused to the resin materials of the first and second tubes, a nichrome wire is wound around the outer periphery of the core member, and both ends of the nichrome wire are used as power connection ends 5b'. Heating element for end connection. 2. Place the heating element 5 horizontally as shown below, wrap the cut edge 5c of the heating element around the rubber ring 4 in a split ring shape around the insertion end 2 of the second tube, and use the wrapped heating element 5 to The tube end connection method according to claim 1, wherein the rubber ring 4 and the heating element 5 are inserted into the tube end fitting gap 3 by pressing the rubber ring 4. A large number of cuts 5c' are provided at one or both longitudinal edges of the strip-like core member 5a made of a plastic material that can be heat-fused to the resin material of the first and second tubes, and the nichrome wire 5b is inserted into the core member 5a. A heating element for connecting a tube end, which passes sequentially through the notches 5c' and is wound in contact with the medial side surface of the core member 5a, and has both ends of the nichrome wire used as power supply connection ends. 3. The tube end connecting method according to claim 1 or 2, wherein the rubber ring 4 is made of heat-resistant rubber. 4. The tube end connecting method according to claim 1, wherein the first tube, the second tube, and the core member 5a of the heating element are made of polyethylene resin. 5 Claims 1, 2, or 3 in which the first tube, the second tube, and the core member 5a of the heating element are made of polypropylene resin.
The pipe end connection method described in . 6. A core member 5a is made of a long flexible plastic plate that can be fused to the first and second pipes, and a large number of notches 5c' are provided at one or both longitudinal edges of the core member. The wire 5b is sequentially passed through the notch 5c' and wound in contact with the medial side surface of the core 5a, and the core member wound with the nichrome wire is wound in a spiral shape to generate a flexible spar-length heat generator. Board material. 7. The flexible digit-length heating plate material according to claim 6, wherein the core member 5a is made of polyethylene. 8. The flexible digit-length heating plate material according to claim 6, wherein the core member 5a is made of polypropylene.