JP7235520B2 - Fusion tube manufacturing method and fusion tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a fusion-bonded tube for connecting resin pipes by fusion-bonding. The present invention also relates to a fused pipe in which resin pipes are connected to each other by fusion.

Metal pipes and resin pipes are used as components of piping. Resin pipes are more resistant to corrosion and more durable than metal pipes. Among the pipes, the fire extinguishing pipe that connects the water tank and the fire hydrant, the fire extinguishing pipe that connects the water tank and the sprinkler, and the plant pipe installed in factories, etc., require water to flow at a high pressure and a large flow rate during use. There is For this reason, studies have been made to increase the flow rate in the resin pipe and to improve the pressure resistance of the resin pipe.

As described in Patent Literatures 1 to 3 below, resin pipes are sometimes connected to each other by butt fusion to manufacture a fusion pipe. In the butt fusion, the ends of the resin pipes are heated and melted from the end faces of the resin pipes using a heater or the like, and then the end faces are crimped to connect the resin pipes. In a fusion pipe manufactured by butt fusion, beads are formed on the inner peripheral surface and the outer peripheral surface of the connecting portion. In addition, in Patent Documents 2 and 3, the bead is treated or processed using a specific member.

JP 2012-37017 A JP-A-11-227051 JP-A-04-321894

In order to flow a liquid at a high pressure and a large flow rate, it is desirable that a pipe in which resin pipes are connected to each other has a small pressure loss and a high pressure resistance. However, if the thickness of the resin pipe is simply increased in order to increase the pressure resistance, the pressure loss increases.

In addition, in a conventional fusion pipe in which resin pipes are connected by fusion, a bead (inner peripheral bead) is formed on the inner peripheral surface of the fusion pipe, resulting in a large pressure loss and a low pressure resistance. sometimes For this reason, a conventional fused pipe having an inner peripheral bead cannot be used as a pipe that requires high flow rate and pressure resistance. In addition, as described in Patent Documents 2 and 3, processing or processing the inner peripheral bead using a specific member in order to ensure flow rate and pressure resistance leads to an increase in manufacturing cost and workload, I don't like it.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a fusion-bonded tube that can reduce the pressure loss and increase the pressure resistance of the resulting fusion-bonded tube. Another object of the present invention is to provide a spliced tube capable of reducing pressure loss and increasing pressure resistance.

According to a broad aspect of the present invention, the step of connecting the end of the first resin pipe and the end of the second resin pipe by fusion to obtain a fusion pipe, The ratio of the inner diameter at the end surface of the first resin pipe to the inner diameter at the end surface of the second resin pipe before connection is 1.02 or more and 1.15 or less, and in the step of obtaining the fusion tube, the first An inner peripheral bead is formed on the inner peripheral surface of the connection portion between the resin pipe and the second resin pipe, and the inner peripheral bead is formed between the first convex portion on the side of the first resin pipe and the and a second projection on the side of the second resin pipe, wherein the inner diameter of the first resin pipe at the maximum height position of the first projection is the maximum height position of the second projection A method for producing a fusion-bonded tube is provided, which obtains a fusion-bonded tube having an inner diameter larger than that of the second resin tube in the above.

In a specific aspect of the method for manufacturing a fusion tube according to the present invention, the combination of the first resin tube and the second resin tube is a combination of a joint main body and a sleeve tube.

In a specific aspect of the method for manufacturing a fusion tube according to the present invention, at least one of the first resin tube and the second resin tube has a bending angle of 45 degrees or more and 135 degrees or less. have

In a specific aspect of the fusion tube manufacturing method according to the present invention, at least one of the first resin tube and the second resin tube has a flange receiving portion.

According to a broad aspect of the present invention, there is provided a fusion pipe in which a first resin pipe and a second resin pipe are connected by fusion, wherein the first resin pipe and the second resin pipe An inner peripheral bead is formed on the inner peripheral surface of the connection portion of the above, and the inner peripheral bead is formed on the first convex portion on the first resin pipe side and the second convex portion on the second resin pipe side. The second resin pipe in a region where the inner peripheral bead is not formed, and has a maximum inner diameter at the end of the first resin pipe in the region where the inner peripheral bead is not formed The ratio to the maximum inner diameter at the end of is 1.02 or more and 1.15 or less, and the inner diameter of the first resin pipe at the maximum height position of the first protrusion is equal to that of the second protrusion A fusion tube is provided that is larger than the inner diameter of the second resin tube at its maximum height.

In a specific aspect of the fusion tube according to the present invention, the inner diameter of the first resin pipe at the maximum height position of the first protrusion is the second at the maximum height position of the second protrusion. 2 to the inner diameter of the resin pipe is 1.02 or more and 1.20 or less.

In a specific aspect of the fusion tube according to the present invention, the maximum inner diameter at the end of the first resin tube in the region where the inner peripheral bead is not formed, the maximum height of the first protrusion The ratio to the inner diameter of the first resin pipe at the position is 1.02 or more and 1.15 or less.

In a specific aspect of the fusion tube according to the present invention, the maximum inner diameter at the end of the second resin tube in the region where the inner peripheral bead is not formed, the maximum height of the second protrusion The ratio to the inner diameter of the second resin pipe at the position is 1.02 or more and 1.18 or less.

In a specific aspect of the fusion tube according to the present invention, the combination of the first resin tube and the second resin tube is a combination of a joint main body and a sleeve tube.

In a specific aspect of the fusion tube according to the present invention, at least one of the first resin tube and the second resin tube has a portion with a bending angle of 45 degrees or more and 135 degrees or less.

In a specific aspect of the fusion pipe according to the present invention, at least one of the first resin pipe and the second resin pipe has a flange receiving portion.

A method for manufacturing a fusion-bonded tube according to the present invention includes a step of connecting an end portion of a first resin pipe and an end portion of a second resin pipe by fusion-bonding to obtain a fusion-bonded pipe. In the method for manufacturing a fusion tube according to the present invention, the ratio of the inner diameter at the end face of the first resin pipe before connection to the inner diameter at the end face of the second resin pipe before connection is 1.02 or more. 15 or less. In the method of manufacturing a fusion pipe according to the present invention, in the step of obtaining the fusion pipe, an inner peripheral bead is formed on the inner peripheral surface of the connecting portion between the first resin pipe and the second resin pipe. obtain a spliced tube with The inner peripheral bead has a first projection on the first resin pipe side and a second projection on the second resin pipe side. In the method of manufacturing a fusion tube according to the present invention, in the step of obtaining the fusion tube, the inner diameter of the first resin tube at the maximum height position of the first protrusion is equal to that of the second protrusion. A fusion tube having an inner diameter larger than that of the second resin tube at the maximum height position is obtained. Since the method of manufacturing a fusion-bonded tube according to the present invention is provided with the above configuration, the resulting fusion-bonded tube can have a reduced pressure loss and an increased pressure resistance.

A fusion pipe according to the present invention is a fusion pipe in which a first resin pipe and a second resin pipe are connected by fusion. In the fusion tube according to the present invention, an inner peripheral bead is formed on the inner peripheral surface of the connecting portion between the first resin tube and the second resin tube. The inner peripheral bead has a first projection on the first resin pipe side and a second projection on the second resin pipe side. In the fusion tube according to the present invention, the maximum inner diameter at the end of the first resin pipe in the region where the inner peripheral bead is not formed is the second maximum inner diameter in the region where the inner peripheral bead is not formed. to the maximum inner diameter at the end of the resin pipe is 1.02 or more and 1.15 or less. In the fusion tube according to the present invention, the inner diameter of the first resin pipe at the maximum height position of the first projection is the same as that of the second resin pipe at the maximum height position of the second projection. larger than the inner diameter. Since the fusion tube according to the present invention has the above configuration, it is possible to reduce the pressure loss and improve the pressure resistance.

FIG. 1 is a cross-sectional view schematically showing a fusion tube according to one embodiment of the present invention. 2(a), (b) and (c) are cross-sectional views for explaining a method for manufacturing a fusion tube according to an embodiment of the present invention.

The present invention will be described in detail below.

A fusion pipe according to the present invention is a fusion pipe in which a first resin pipe and a second resin pipe are connected by fusion. In the fusion tube according to the present invention, an inner peripheral bead is formed on the inner peripheral surface of the connecting portion between the first resin tube and the second resin tube. The inner peripheral bead has a first projection on the first resin pipe side and a second projection on the second resin pipe side. A region R1a is defined as a region of the first resin pipe where the inner peripheral bead is not formed. A region of the second resin pipe where the inner peripheral bead is not formed is defined as a region R2a. In the fusion tube according to the present invention, the ratio of the maximum inner diameter at the end of the first resin pipe in the region R1a to the maximum inner diameter at the end of the second resin pipe in the region R2a is 1. .02 or more and 1.15 or less. In the fusion tube according to the present invention, the inner diameter of the first resin pipe at the maximum height position of the first projection is the same as that of the second resin pipe at the maximum height position of the second projection. larger than the inner diameter.

Since the fusion tube according to the present invention has the above configuration, it is possible to reduce the pressure loss and improve the pressure resistance. In the fusion tube according to the present invention, the flow rate of liquid flowing inside can be increased, and in particular, the flow rate of fluid flowing from the first resin tube to the second resin tube can be increased. In the fused tube according to the present invention, since the specific inner peripheral bead is formed, the above effect can be enhanced as compared with the conventional fused tube in which the inner peripheral bead is formed. Further, in the fusion tube according to the present invention, the pressure loss can be effectively reduced and the pressure resistance can be effectively increased without removing the inner peripheral bead. can effectively increase the flow rate of the fluid flowing through the

A method for manufacturing a fusion-bonded tube according to the present invention includes a step of connecting an end portion of a first resin pipe and an end portion of a second resin pipe by fusion-bonding to obtain a fusion-bonded pipe. In the method for manufacturing a fusion tube according to the present invention, the ratio of the inner diameter at the end face of the first resin pipe before connection to the inner diameter at the end face of the second resin pipe before connection is 1.02 or more. 15 or less. In the method of manufacturing a fusion pipe according to the present invention, in the step of obtaining the fusion pipe, an inner peripheral bead is formed on the inner peripheral surface of the connecting portion between the first resin pipe and the second resin pipe. obtain a spliced tube with The inner peripheral bead has a first projection on the first resin pipe side and a second projection on the second resin pipe side. In the method of manufacturing a fusion tube according to the present invention, in the step of obtaining the fusion tube, the inner diameter of the first resin tube at the maximum height position of the first protrusion is equal to that of the second protrusion. A fusion tube having an inner diameter larger than that of the second resin tube at the maximum height position is obtained.

Since the method of manufacturing a fusion-bonded tube according to the present invention is provided with the above configuration, the resulting fusion-bonded tube can have a reduced pressure loss and an increased pressure resistance. In the method for manufacturing a fusion pipe according to the present invention, the flow rate of the liquid flowing inside the obtained fusion pipe can be increased. flow rate can be increased. In the method of manufacturing a fusion tube according to the present invention, since a specific inner peripheral bead is formed, the resulting fusion tube has the above-described characteristics compared to the conventional method of manufacturing a fusion tube in which an inner peripheral bead is formed. You can increase the effect. Further, in the method of manufacturing a spliced tube according to the present invention, the pressure loss can be effectively reduced and the pressure resistance can be effectively increased without removing the inner peripheral bead. As a result, the flow rate of the fluid flowing inside can be effectively increased. Furthermore, since the method of manufacturing a spliced tube according to the present invention has the above configuration, it is possible to connect resin tubes having different diameters, and there is no need to remove the inner peripheral bead. Therefore, the fusion tube can be manufactured easily and at low cost.

Fusion is generally a method of connecting resin pipes having substantially the same inner diameter and outer diameter at their ends, and in particular, a method of connecting resin pipes having substantially uniform inner diameters at their ends. When connecting resin pipes with different inner and outer diameters at the ends by fusion, the inner surface of one of the resin pipes is shaved to make the diameter almost the same, and then the resin pipes are connected to each other. Connecting.

Also, butt fusion is known as a representative fusion method. In a fusion tube manufactured by fusion such as butt fusion, a bead (inner peripheral bead) is formed on the inner peripheral surface of the connecting portion. The inner peripheral bead generally has a first convex portion on one resin pipe side and a second convex portion on the other resin pipe side, and the height of the first convex portion and the height of the second convex portion are The height is approximately the same. In a fused tube manufactured by butt fusion, there is a step between the portion where the inner peripheral bead is formed and the portion where the inner peripheral bead is not formed. may not be sufficiently increased, or the pressure resistance may be low. If the thickness of the resin pipe is increased or the inner peripheral bead is shaved in order to secure the flow rate and pressure resistance, the manufacturing cost and the amount of work increase. In particular, when trying to increase the thickness of a resin pipe obtained by injection molding (for example, a resin pipe having a bending angle such as a T-shaped pipe and an L-shaped pipe), it is necessary to change the design of the mold. , which further increases the manufacturing cost.

The present inventor has found a configuration that can reduce pressure loss and increase pressure resistance even when resin pipes having different inner diameters are connected by fusion such as butt fusion. In addition, the present inventors have found a structure capable of reducing pressure loss and increasing pressure resistance in a fusion tube having an inner peripheral bead. Instead of connecting resin pipes with the same inner diameter, the inventor intentionally connects resin pipes with different inner diameters to form a specific inner peripheral bead, thereby reducing the pressure loss. , and that the pressure resistance can be improved.

In the fusion tube according to the present invention and the fusion tube obtained by the manufacturing method of the fusion tube according to the present invention, the connecting portion between the first resin tube and the second resin tube has a specific structure. It is possible to reduce the pressure loss when the liquid is passed through and to improve the pressure resistance, and as a result, it is possible to effectively increase the flow rate of the fluid flowing inside. In a conventional fusion tube having an inner peripheral bead, a step caused by the inner peripheral bead tends to disturb the flow of the liquid. On the other hand, in the fusion-bonded pipe according to the present invention and the fusion-bonded pipe obtained by the manufacturing method of the fusion-bonded pipe according to the present invention, a step is formed at the connecting portion between the first resin pipe and the second resin pipe. Since it can be formed gently, the liquid can flow well along the step, and the flow of the liquid is less likely to be disturbed. Therefore, it is possible to effectively reduce the pressure loss when the liquid is passed through, and to effectively improve the pressure resistance.

In the fusion tube according to the present invention and the fusion tube obtained by the manufacturing method of the fusion tube according to the present invention, the thickness of one of the resin tubes is reduced (inside diameter is increased), the pressure loss can be reduced and the pressure resistance can be increased.

In the fusion tube according to the present invention and the fusion tube obtained by the manufacturing method of the fusion tube according to the present invention, when the liquid is passed from the first resin tube side and when the liquid is passed from the second resin tube side In any case, the pressure loss can be reduced and the pressure resistance can be enhanced.

(fused tube)
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a fusion tube according to one embodiment of the present invention.

A fusion pipe 10 is a fusion pipe in which a first resin pipe 1 and a second resin pipe 2 are connected by fusion. A fusion pipe 10 is a resin pipe connector in which a first resin pipe 1 and a second resin pipe 2 are integrated by fusion. Each of the first resin pipe 1 and the second resin pipe 2 is tubular.

An inner peripheral bead 3 is formed on the inner peripheral surface of the connecting portion between the first resin pipe 1 and the second resin pipe 2 . Each of the first resin pipe 1 and the second resin pipe 2 has an inner peripheral bead 3 . The inner peripheral bead 3 has a first convex portion 1a on the first resin pipe 1 side and a second convex portion 2a on the second resin pipe 2 side. The first resin pipe 1 has a first projection 1a. The second resin pipe 2 has a second protrusion 2a. The inner bead 3 has an inner bead on the first protrusion 1a and an inner bead on the second protrusion 2a.

An outer peripheral bead 4 is formed on the outer peripheral surface of the connecting portion between the first resin pipe 1 and the second resin pipe 2 . Each of the first resin pipe 1 and the second resin pipe 2 has an outer peripheral bead 4 . The outer bead 4 has a third protrusion 1b on the first resin pipe 1 side and a fourth protrusion 2b on the second resin pipe 2 side. The first resin pipe 1 has a third protrusion 1b. The second resin pipe 2 has a fourth projection 2b. The outer bead 4 has an inner bead corresponding to the third protrusion 1b and an inner bead corresponding to the fourth protrusion 2b.

Note that FIG. 1 shows the first resin pipe 1 after connection and the second resin pipe 2 after connection. FIG. 2A, which will be described later, shows the first resin pipe 1 before connection and the second resin pipe 2 before connection.

In the first resin pipe 1 after connection, a region where the inner peripheral bead 3 of the first resin pipe 1 is not formed is defined as a region R1a. A region R1a is a region between X1a and X1b in FIG.

In the second resin pipe 2 after connection, a region where the inner peripheral bead 3 of the second resin pipe 2 is not formed is defined as a region R2a. Region R2a is the region between X2a and X2b in FIG.

In the first resin pipe 1 after connection, the end portion is a region from the end face of the first resin pipe 1 to 3 cm toward the inside in the direction in which the first resin pipe 1 extends (region R1 in FIG. 1; A region R1 is a region between X0 and X1a in FIG. In the first resin pipe 1 after connection, the region R1a extends from the end surface of the first resin pipe 1 toward the inside in the direction in which the first resin pipe 1 extends (region R1 in FIG. 1) up to 3 cm. , excluding the region where the inner peripheral bead 3 is formed (region R1b in FIG. 1; region R1b is the region between X0 and X1b in FIG. 1). However, when the bead width of the first convex portion 1a is 3 cm or more, the end portion of the first resin pipe 1 after connection means the first resin pipe 1 from the end surface of the first resin pipe 1. It refers to the area up to the bead width +2.5 cm of the first projection 1a toward the inside in the direction in which the tube 1 extends. In general, the bead width of the first convex portion 1a is less than 2 cm.

In the second resin pipe 2 after connection, the end portion is a region from the end surface of the second resin pipe 2 to 3 cm toward the inside in the direction in which the second resin pipe 2 extends (region R2 in FIG. 1; A region R2 is a region between X0 and X2a in FIG. In the second resin pipe 2 after connection, the region R2a extends from the end surface of the second resin pipe 2 toward the inside in the direction in which the second resin pipe 2 extends (region R2 in FIG. 1) up to 3 cm. , excluding the region where the inner peripheral bead 3 is formed (region R2b in FIG. 1; region R2b is the region between X0 and X1b in FIG. 1). However, when the bead width of the second convex portion 2a portion is 3 cm or more, in the second resin pipe 2 after connection, the end portion means the second resin pipe 2 from the end surface of the second resin pipe 2. It refers to the area up to the bead width of the second convex portion 2a + 2.5 cm toward the inside in the direction in which the tube 2 extends. In general, the bead width of the second protrusion 2a is less than 2 cm.

In the first resin pipe 1 before connection, the term "end portion" refers to a region from the end face of the first resin pipe 1 toward the inside in the direction in which the first resin pipe 1 extends up to 3 cm.

In the second resin pipe 2 before connection, the term "end portion" refers to a region extending from the end surface of the second resin pipe 2 toward the inside in the direction in which the second resin pipe 2 extends up to 3 cm.

In the first resin pipe 1 after connection and the second resin pipe 2 after connection, the maximum inner diameter at the end of the first resin pipe 1 in region R1a is the maximum inner diameter of the second resin pipe 2 in region R2a. The ratio to the maximum inner diameter at the end (maximum inner diameter at the end of the first resin pipe 1 in the region R1a/maximum inner diameter at the end of the second resin pipe 2 in the region R2a) is referred to as "ratio (A)". and Therefore, the ratio (A) is the maximum inner diameter at the end of the first resin pipe 1 in the region where the inner peripheral bead is not formed in the fusion tube 10, in the region where the inner peripheral bead is not formed. It is the ratio to the maximum inner diameter at the end of the second resin pipe 2 .

From the viewpoint of reducing pressure loss and improving pressure resistance, the ratio (A) is 1.02 or more and 1.15 or less. In the first resin pipe 1 after connection and the second resin pipe 2 after connection, the maximum inner diameter at the end of the first resin pipe 1 in the region R1a and the maximum inner diameter of the second resin pipe 2 in the region R2a Different from the maximum inner diameter at the end.

If the ratio (A) is less than 1.02, the pressure loss increases due to the inner peripheral bead, and the flow rate may not be sufficiently increased, or the pressure resistance may decrease. . If the ratio (A) exceeds 1.15, the pressure loss increases due to the step formed by the difference in inner diameter between the first resin pipe and the second resin pipe, and the flow rate is sufficiently increased. It may not be possible, or the pressure resistance may be lowered.

The ratio (A) is preferably 1.04 or more, more preferably 1.06 or more, preferably 1.10 or less, and more preferably 1.08 or less. When the ratio (A) is equal to or more than the lower limit and equal to or less than the upper limit, the pressure loss can be further reduced, and the pressure resistance can be further increased. As a result, the flow rate can be further increased. can.

The maximum inner diameter at the end of the first resin pipe 1 after connection in the region R1a often matches the maximum inner diameter at the end of the first resin pipe 1 before connection. The maximum inner diameter at the end of the second resin pipe 2 after connection in the region R2a often matches the maximum inner diameter at the end of the second resin pipe 2 before connection. The maximum inner diameter at the end of the first resin pipe 1 after connection in the region R1a often matches the inner diameter at the end face of the first resin pipe 1 before connection. The maximum inner diameter at the end of the second resin pipe 2 after connection in the region R2a often matches the inner diameter at the end face of the second resin pipe 2 before connection. Therefore, the ratio (A) described above, the ratio (A') described later, and the ratio (A'') described later often match each other.

In the first resin pipe 1 after connection and the second resin pipe 2 after connection, the inner diameter of the first resin pipe 1 at the maximum height position of the first convex portion 1a is the width of the second convex portion 2a. Ratio to the inner diameter of the second resin pipe 2 at the maximum height position (the inner diameter of the first resin pipe 1 at the maximum height position of the first protrusion 1a / the second at the maximum height position of the second protrusion 2a) 2) is defined as "ratio (B)". Therefore, in the fusion tube 10, the ratio (B) is the second to the inner diameter of the resin pipe 2.

From the viewpoint of reducing pressure loss and increasing pressure resistance, in the first resin pipe 1 after connection and the second resin pipe 2 after connection, the first The inner diameter of the resin pipe 1 is larger than the inner diameter of the second resin pipe 2 at the maximum height position of the second protrusion 2a. In the fusion tube 10, the inner diameter of the first resin pipe 1 at the maximum height position of the first projection 1a is larger than the inner diameter of the second resin pipe 2 at the maximum height position of the second projection 2a. big. Therefore, in the present invention, the above ratio (B) exceeds 1.

The ratio (B) is preferably 1.02 or more, more preferably 1.05 or more, still more preferably 1.07 or more, preferably 1.20 or less, more preferably 1.19 or less, and still more preferably 1.07 or more. 12 or less. When the ratio (B) is equal to or higher than the lower limit and equal to or lower than the upper limit, the pressure loss can be further reduced, and as a result, the flow rate can be further increased.

In the first resin pipe 1 after connection and the second resin pipe 2 after connection, the maximum inner diameter at the end of the first resin pipe 1 in the region R1a at the maximum height position of the first convex portion 1a The ratio to the inner diameter of the first resin pipe 1 (the maximum inner diameter at the end of the first resin pipe 1 in the region R1a/the inner diameter of the first resin pipe 1 at the maximum height position of the first convex portion 1a) is Let it be "ratio (C)". Therefore, the ratio (C) is the maximum height position of the first convex portion 1a of the maximum inner diameter at the end of the first resin pipe 1 in the region where the inner peripheral bead is not formed in the fusion tube 10. is the ratio to the inner diameter of the first resin pipe 1 in .

The ratio (C) is preferably 1.02 or more, more preferably 1.03 or more, preferably 1.15 or less, more preferably 1.08 or less, and still more preferably 1.05 or less. When the ratio (C) is equal to or more than the lower limit and equal to or less than the upper limit, the pressure loss can be further reduced, and the pressure resistance can be further improved. As a result, the flow rate can be further increased. can.

In the first resin pipe 1 after connection and the second resin pipe 2 after connection, the maximum inner diameter at the end of the second resin pipe 2 in the region R2a at the maximum height position of the second convex portion 2a The ratio to the inner diameter of the second resin pipe 2 (the maximum inner diameter at the end of the second resin pipe 2 in the region R2a/the inner diameter of the second resin pipe 2 at the maximum height position of the second convex portion 2a) is Let it be "ratio (D)". Therefore, the ratio (D) is the maximum height position of the second convex portion 2a of the maximum inner diameter at the end of the second resin pipe 2 in the region where the inner peripheral bead is not formed in the fusion tube 10. is the ratio to the inner diameter of the second resin pipe 2 in .

The ratio (D) is preferably 1.02 or more, more preferably 1.03 or more, preferably 1.18 or less, more preferably 1.08 or less, and still more preferably 1.05 or less. When the ratio (D) is equal to or more than the lower limit and equal to or less than the upper limit, the pressure loss can be further reduced, and the pressure resistance can be further improved. As a result, the flow rate can be further increased. can.

In the first resin pipe 1 after connection and the second resin pipe 2 after connection, the second resin pipe 2 in the region R2a has the smallest outer diameter at the end of the first resin pipe 1 in the region R1a. The ratio to the minimum outer diameter at the end of the (minimum outer diameter at the end of the first resin pipe 1 in the region R1a/minimum outer diameter at the end of the second resin pipe 2 in the region R2a) (E)”. Therefore, the ratio (E) is the minimum outer diameter at the end of the first resin pipe 1 in the region where the inner peripheral bead is not formed in the fusion tube 10, in the region where the inner peripheral bead is not formed. to the minimum outer diameter at the end of the second resin pipe 2.

From the viewpoint of practical use, the ratio (E) is preferably 0.98 or more, more preferably 0.99 or more, still more preferably 0.995 or more, preferably 1.02 or less, and more preferably 1.01. 1.005 or less, more preferably 1.005 or less. Most preferably, the ratio (E) is 1.00. The minimum outer diameter at the end of the first resin pipe 1 in the region R1a and the minimum outer diameter at the end of the second resin pipe 2 in the region R2a may be different.

The minimum outer diameter at the end of first resin pipe 1 after connection in region R1a often matches the minimum outer diameter at the end of first resin pipe 1 before connection. The minimum outer diameter at the end of the second resin pipe 2 before connection in the region R2a often matches the minimum outer diameter at the end of the second resin pipe 2 before connection. The minimum outer diameter at the end of the first resin pipe 1 after connection in the region R1a often matches the outer diameter at the end face of the first resin pipe 1 before connection. The minimum outer diameter at the end of the second resin pipe 2 before connection in the region R2a often matches the outer diameter at the end face of the second resin pipe 2 before connection. Therefore, the ratio (E), the ratio (E') described above, and the ratio (E'') described later often match each other.

2(a), (b) and (c) are cross-sectional views for explaining a method for manufacturing a fusion tube according to an embodiment of the present invention.

FIG. 2(a) is a cross-sectional view schematically showing the first resin pipe 1 and the second resin pipe 2 before manufacturing the fusion pipe.

In the first resin pipe 1 before connection and the second resin pipe 2 before connection, the ratio of the inner diameter at the end surface of the first resin pipe 1 to the inner diameter at the end surface of the second resin pipe 2 (first resin pipe The inner diameter at the end face of the pipe 1/the inner diameter at the end face of the second resin pipe 2) is defined as "ratio (A')".

From the viewpoint of reducing pressure loss and improving pressure resistance, the ratio (A′) is 1.02 or more and 1.15 or less. In the first resin pipe 1 before connection and the second resin pipe 2 before connection, the inner diameter at the end face of the first resin pipe 1 is different from the inner diameter at the end face of the second resin pipe 2 .

If the ratio (A′) is less than 1.02, the pressure loss increases due to the inner peripheral bead, and the flow rate may not be sufficiently increased, or the pressure resistance may decrease. be. If the above ratio (A′) exceeds 1.15, the pressure loss increases due to the step formed by the difference in inner diameter between the first resin pipe and the second resin pipe, and the flow rate is sufficiently increased. It may not be possible to do so, or the pressure resistance may be lowered.

The ratio (A') is preferably 1.04 or more, more preferably 1.06 or more, preferably 1.10 or less, and more preferably 1.08 or less. When the ratio (A′) is equal to or higher than the lower limit and equal to or lower than the upper limit, the pressure loss can be further reduced and the pressure resistance can be further increased, resulting in a further increase in the flow rate. can be done.

In the first resin pipe 1 before connection and the second resin pipe 2 before connection, the ratio of the maximum inner diameter at the end of the first resin pipe 1 to the maximum inner diameter at the end of the second resin pipe 2 ( The maximum inner diameter at the end of the first resin pipe 1/the maximum inner diameter at the end of the second resin pipe 2) is defined as "ratio (A'')".

The above ratio (A'') is preferably 1.02 or more, more preferably 1.04 or more, still more preferably 1.06 or more, preferably 1.15 or less, more preferably 1.10 or less, still more preferably 1.08 or less. When the ratio (A'') is equal to or more than the lower limit and equal to or less than the upper limit, the pressure loss can be further reduced and the pressure resistance can be further increased, resulting in a further increase in the flow rate. be able to.

In the first resin pipe 1 before connection and the second resin pipe 2 before connection, the ratio (first The outer diameter at the end surface of the second resin pipe 1/the outer diameter at the end surface of the second resin pipe 2) is defined as "ratio (E')".

From the viewpoint of practical use, the above ratio (E') is preferably 0.98 or more, more preferably 0.99 or more, still more preferably 0.995 or more, preferably 1.02 or less, and more preferably 1.02 or less. 01 or less, more preferably 1.005 or less. Most preferably, the ratio (E') is 1.00. The outer diameter at the end face of the first resin pipe 1 and the outer diameter at the end face of the second resin pipe 2 may be different.

In the first resin pipe 1 before connection and the second resin pipe 2 before connection, the minimum outer diameter at the end of the first resin pipe 1 with respect to the minimum outer diameter at the end of the second resin pipe 2 The ratio (minimum outer diameter at the end of the first resin pipe 1/minimum outer diameter at the end of the second resin pipe 2) is defined as "ratio (E'')".

From the viewpoint of practical use, the ratio (E'') is preferably 0.98 or more, more preferably 0.99 or more, still more preferably 0.995 or more, preferably 1.02 or less, more preferably 1 0.01 or less, more preferably 1.005 or less. Most preferably, the ratio (E'') is 1.00. The outer diameter at the end face of the first resin pipe 1 and the outer diameter at the end face of the second resin pipe 2 may be different.

Using the first resin pipe 1 and the second resin pipe 2 shown in FIG. 2(a), the end portion of the first resin pipe 1 is changed through the states shown in FIGS. and the end of the second resin pipe 2 are connected by fusion to obtain the fusion-bonded pipe 10 .

The fusion bonding method is not particularly limited, and conventionally known methods can be used. The fusion includes a heating step of heating the end of the first resin pipe 1 before connection and the end of the second resin pipe 2 before connection, the heated end of the first resin pipe 1, It is preferable to include a crimping step of crimping the heated end of the second resin pipe 2 . In the heating step, it is preferable to heat the end surface of the first resin pipe 1 before connection, and it is preferable to heat the end surface of the second resin pipe 2 before connection. In the crimping step, it is preferable to crimp the heated end face of the first resin pipe 1 and the heated end face of the second resin pipe 2 .

FIG. 2(b) is a cross-sectional view for explaining the heating process in fusion.

In the heating step, it is preferable to use the heater H to heat the end of the first resin pipe 1 and the end of the second resin pipe 2 . In the heating by the heater H, it is preferable to heat from the end face side of the first resin pipe 1 and the end face side of the second resin pipe.

The heating temperature in the heating step can be appropriately changed depending on the type of compounding components such as resin contained in the first resin pipe 1 and the second resin pipe 2 . The heating temperature is preferably 230° C. or higher, more preferably 235° C. or higher, preferably 250° C. or lower, and more preferably 245° C. or lower.

The heating time in the heating process depends on the type of compounding components such as resin contained in the first resin pipe 1 and the second resin pipe 2 and the diameter of the first resin pipe 1 and the second resin pipe 2. It can be changed as appropriate.

FIG. 2(c) is a cross-sectional view for explaining a crimping step in fusion bonding.

The pressure in the crimping step can be appropriately changed depending on the type of compounding components such as resin contained in the first resin pipe 1 and the second resin pipe 2 . The pressure is preferably 1 MPa or higher, more preferably 1.2 MPa or higher, preferably 3 MPa or lower, and more preferably 2.8 MPa or lower.

The crimping time in the crimping process depends on the types of compounding components such as resins contained in the first resin pipe 1 and the second resin pipe 2 and the diameters of the first resin pipe 1 and the second resin pipe 2. It can be changed as appropriate.

By connecting the first resin pipe 1 and the second resin pipe 2 by fusion as described above, the fusion pipe 10 shown in FIG. 1 can be manufactured.

In the method of manufacturing a fusion pipe according to the present invention, since the inner diameters of the end faces of the first resin pipe and the second resin pipe satisfy a specific ratio, the connection between the first resin pipe and the second resin pipe In part, a fused tube having a specific structure can be obtained satisfactorily.

(First resin pipe and second resin pipe)
The first resin pipe contains resin. The second resin pipe contains resin. The resin contained in the first resin pipe and the resin contained in the second resin pipe may be the same or different. Only one kind of the resin may be used, or two or more kinds thereof may be used in combination.

Examples of the resin include polyolefin resin and vinyl chloride resin.

From the viewpoint of further increasing pressure resistance, the resin is preferably polyolefin resin or vinyl chloride resin.

Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. Only one kind of the polyolefin resin may be used, or two or more kinds thereof may be used in combination.

From the viewpoint of further increasing pressure resistance, the polyolefin resin is preferably polyethylene or polypropylene, more preferably polyethylene. The polyethylene may be crosslinked polyethylene.

Examples of the polyethylene include homopolymers of ethylene and copolymers of monomers containing ethylene. It is preferable that 50% by weight or more (preferably 80% by weight or more, more preferably 90% by weight or more) of the monomers constituting the polyethylene is ethylene. Examples of the polypropylene include homopolymers of propylene and copolymers of monomers containing propylene. It is preferable that 50% by weight or more (preferably 80% by weight or more, more preferably 90% by weight or more) of the monomers constituting the polypropylene is propylene.

The resin content in 100% by weight of the first resin pipe or 100% by weight of the second resin pipe is preferably 20% by weight or more, more preferably 30% by weight or more, and preferably 80% by weight. % or less, more preferably 70% by weight or less. Pressure resistance can be further improved when the content of the resin is equal to or more than the lower limit and equal to or less than the upper limit.

The first resin pipe may contain fibers. The second resin pipe may contain fibers. Only the first resin pipe may contain the fibers, only the second resin pipe may contain the fibers, and both the first resin pipe and the second resin pipe may contain the fibers. It may contain the fibers described above. Only one type of the fibers may be used, or two or more types may be used in combination.

The fibers may be inorganic fibers or organic fibers.

Examples of the inorganic fibers include glass fibers, carbon fibers, silicon/titanium/carbon composite fibers, boron fibers, and metal fibers.

Examples of the organic fibers include aramid fibers, vinylon fibers, polyester fibers, and polyamide fibers.

From the viewpoint of further increasing the pressure resistance, the fibers are preferably glass fibers.

The average fiber length of the fibers is preferably 100 µm or more, more preferably 200 µm or more, still more preferably 300 µm or more, preferably 1500 µm or less, more preferably 1000 µm or less, and still more preferably 800 µm or less. When the average fiber length of the fibers is equal to or more than the lower limit and equal to or less than the upper limit, pressure resistance can be further enhanced.

The average fiber length is determined by determining the fiber length of one fiber and averaging the fiber lengths of a plurality of fibers. The fiber length is the distance between one end and the other end of the fiber when the fiber is linear.

The average fiber diameter of the fibers is preferably 5 µm or more, more preferably 7 µm or more, still more preferably 9 µm or more, preferably 17 µm or less, and more preferably 14 µm or less. When the average fiber diameter of the fibers is equal to or more than the lower limit and equal to or less than the upper limit, pressure resistance can be further enhanced.

The average fiber diameter is determined by determining the fiber diameter of one fiber and averaging the fiber diameters of a plurality of fibers.

The content of the fiber in 100% by weight of the first resin pipe or 100% by weight of the second resin pipe is preferably 5% by weight or more, more preferably 10% by weight or more, and preferably 30% by weight. % or less, more preferably 25 wt % or less. When the content of the fibers is equal to or more than the lower limit and equal to or less than the upper limit, pressure resistance can be further enhanced.

The first resin pipe and the second resin pipe are each a compatibilizer, a stabilizer, a stabilizing aid, a lubricant, a processing aid, an impact modifier, a heat resistance improver, an antioxidant, and an ultraviolet absorber. , light stabilizers, fillers, pigments and plasticizers. Each of the above other components may be used alone or in combination of two or more.

Examples of the compatibilizing agent include maleic acid-modified polyolefin, silane-modified polyolefin, and chlorinated polyolefin. These compatibilizers are not included in the above polyolefin resin. Only one type of the compatibilizing agent may be used, or two or more types may be used in combination.

Examples of the stabilizer include heat stabilizers and heat stabilization aids. Examples of the heat stabilizer include organic tin stabilizers, lead stabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, and barium-cadmium stabilizers. Examples of the organic tin stabilizer include dibutyltin mercapto, dioctyltin mercapto, dimethyltin mercapto, dibutyltin mercapto, dibutyltin maleate, dibutyltin maleate polymer, dioctyltin maleate, dioctyltin maleate polymer, dibutyltin laurate, and dibutyltin laurate polymer and the like. Only one of the above stabilizers may be used, or two or more thereof may be used in combination.

Examples of the heat stabilization aid include epoxidized soybean oil, phosphate ester, polyol, hydrotalcite, and zeolite. Only one type of the heat stabilization aid may be used, or two or more types may be used in combination.

The lubricants include internal lubricants and external lubricants. The internal lubricant is used for the purpose of reducing the flow viscosity of the molten resin during molding and preventing frictional heat generation. Examples of the internal lubricant include butyl stearate, lauryl alcohol, stearyl alcohol, epoxy soybean oil, glycerin monostearate, stearic acid, and bisamide. The external lubricant is used for the purpose of increasing the sliding effect between the molten resin and the metal surface during molding. Examples of the external lubricant include paraffin wax, polyolefin wax, ester wax, and montanic acid wax. Only one type of the lubricant may be used, or two or more types may be used in combination.

Examples of the processing aid include acrylic processing aids. Examples of the acrylic processing aid include alkyl acrylate-alkyl methacrylate copolymers having a weight average molecular weight of 100,000 to 2,000,000. Specifically, n-butyl acrylate-methyl methacrylate copolymers, and 2-ethylhexyl acrylate-methyl methacrylate-butyl methacrylate copolymer and the like. Only one type of the processing aid may be used, or two or more types may be used in combination.

Examples of the impact modifier include methyl methacrylate-butadiene-styrene copolymer (MBS) and acrylic rubber. Only one type of the impact modifier may be used, or two or more types may be used in combination.

Examples of the antioxidant include phenol-based antioxidants. Only one kind of the antioxidant may be used, or two or more kinds thereof may be used in combination.

Examples of the ultraviolet absorber include salicylic acid ester-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers. As for the said ultraviolet absorber, only 1 type may be used and 2 or more types may be used together.

Examples of the light stabilizer include hindered amine light stabilizers. As for the said light stabilizer, only 1 type may be used and 2 or more types may be used together.

Examples of the filler include calcium carbonate and talc. Only one kind of the filler may be used, or two or more kinds thereof may be used in combination.

Examples of the pigment include organic pigments and inorganic pigments. Examples of the organic pigments include azo-based organic pigments, phthalocyanine-based organic pigments, threne-based organic pigments, and dye lake-based organic pigments. Examples of the inorganic pigments include oxide-based inorganic pigments, molybdenum chromate-based inorganic pigments, sulfide/selenide-based inorganic pigments, ferrocyanide-based inorganic pigments, and the like. Only one type of the pigment may be used, or two or more types may be used in combination.

The plasticizer may be added for the purpose of improving workability during molding. Since the heat resistance of the resin pipe may decrease due to the addition of the plasticizer, the smaller the amount of the plasticizer added, the better. Examples of the plasticizer include dibutyl phthalate, di-2-ethylhexyl phthalate, and di-2-ethylhexyl adipate. Only one type of the plasticizer may be used, or two or more types may be used in combination.

The first resin pipe may have a one-layer structure, a two-layer structure, or a three-layer or more structure. The first resin pipe may be a single-layer pipe or a multi-layer pipe. The second resin pipe may have a one-layer structure, a two-layer structure, or a three-layer or more structure. The first resin pipe may be a single-layer pipe or a multi-layer pipe. The second resin pipe may be a single-layer pipe or a multi-layer pipe.

The combination of the first resin pipe and the second resin pipe may be a combination of a single-layer pipe and a single-layer pipe, a combination of a single-layer pipe and a multi-layer pipe, or a multi-layer pipe. Combinations of tubes and multi-layer tubes are also possible.

A combination of the first resin pipe and the second resin pipe is preferably a combination of the joint main body and the sleeve pipe. In this case, the first resin pipe may be the joint body and the second resin pipe may be the sleeve pipe, or the first resin pipe may be the sleeve pipe and the second resin pipe may be the joint body. There may be. When the combination of the first resin pipe and the second resin pipe is the combination of the joint main body and the sleeve pipe, the fusion pipe is a joint.

The joint body preferably has a portion with a bending angle of 45 degrees or more and 135 degrees or less.

At least one of the first resin pipe and the second resin pipe preferably has a portion with a bending angle of 45 degrees or more and 135 degrees or less.

Examples of the resin pipe having the bending angle include a T-shaped pipe and an L-shaped pipe.

A resin pipe having a bending angle such as a T-shaped pipe and an L-shaped pipe has low strength at the bent portion. Therefore, in the conventional fusion pipe, in which resin pipes having a bent angle are connected by fusion, the pressure resistance is not sufficiently high, and when the flow rate is increased, the bent portion may break. .

On the other hand, in the fusion tube according to the present invention and the fusion tube obtained by the method for manufacturing the fusion tube according to the present invention, even if a resin tube having a bending angle is used as a constituent member of the fusion tube, Since the pressure loss can be reduced and the pressure resistance can be increased, the fusion tube is less likely to break even if the flow rate is increased. In the fusion tube according to the present invention and the method for manufacturing the fusion tube according to the present invention, at least one of the first resin tube and the second resin tube is a resin tube having the above bending angle. In addition, the effects of the present invention are exhibited more effectively.

At least one of the first resin pipe and the second resin pipe preferably has a flange receiving portion.

In the fusion tube according to the present invention and the fusion tube obtained by the manufacturing method of the fusion tube according to the present invention, even if all the ends of the first resin tube are connected by the second resin tube, Alternatively, they may be connected by a third resin pipe different from the second resin pipe. In the fusion tube according to the present invention and the fusion tube obtained by the manufacturing method of the fusion tube according to the present invention, even if all the ends of the second resin tube are connected by the first resin tube, Alternatively, they may be connected by a fourth resin pipe different from the first resin pipe.

EXAMPLES The present invention will now be described in detail with reference to examples and comparative examples. The invention is not limited to the following examples.

(Example 1)
A 150A elbow having dimensions shown in Table 1 was prepared as the first resin pipe. A 150A straight pipe having dimensions shown in Table 1 was prepared as the second resin pipe.

The end of the first resin pipe and the end of the second resin pipe are heated to 235 from the end face of the first resin pipe and the end face of the second resin pipe using a heater ("DELTA160V1" manufactured by Ritmo Co., Ltd.). °C for 35 seconds. After heating, the heater was removed, and the first resin pipe and the second resin pipe were crimped for 2 minutes at a pressure of 1.5 MPa. In this way, a fused pipe was produced in which the first resin pipe and the second resin pipe were connected by butt fusion.

(Comparative example 1)
A fused tube was obtained in the same manner as in Example 1 except that a 150A elbow having dimensions shown in Table 1 was used as the first resin tube.

(Example 2)
A 200A elbow having dimensions shown in Table 1 was prepared as the first resin pipe. A 200A straight pipe having dimensions shown in Table 1 was prepared as the second resin pipe.

The end of the first resin pipe and the end of the second resin pipe are heated to 235 from the end face of the first resin pipe and the end face of the second resin pipe using a heater ("DELTA160V1" manufactured by Ritmo Co., Ltd.). °C for 55 seconds. After heating, the heater was removed, and the first resin pipe and the second resin pipe were crimped at a pressure of 1.2 MPa for 2.5 minutes. In this way, a fused pipe was produced in which the first resin pipe and the second resin pipe were connected by butt fusion.

(Comparative example 2)
A fused tube was obtained in the same manner as in Example 2, except that a 200A elbow having dimensions shown in Table 1 was used as the first resin tube.

(Example 3)
A 125A cheese having dimensions shown in Table 1 was prepared as a first resin tube. A 125A straight pipe having dimensions shown in Table 1 was prepared as the second resin pipe.

The end of the first resin pipe and the end of the second resin pipe are heated to 235 from the end face of the first resin pipe and the end face of the second resin pipe using a heater ("DELTA160V1" manufactured by Ritmo Co., Ltd.). °C for 34 seconds. After heating, the heater was removed, and the first resin pipe and the second resin pipe were crimped for 2 minutes at a pressure of 1.5 MPa. In this way, a fused pipe was produced in which the first resin pipe and the second resin pipe were connected by butt fusion.

(Comparative Example 3)
A fusion spliced tube was obtained in the same manner as in Example 3 except that a 125A cheese having dimensions shown in Table 1 was used as the first resin tube.

(Example 4)
A 200A cheese having dimensions shown in Table 1 was prepared as a first resin pipe. A 200A straight pipe having dimensions shown in Table 1 was prepared as the second resin pipe.

The end of the first resin pipe and the end of the second resin pipe are heated at 235 degrees from the end face of the first resin pipe and the end face of the second resin pipe using a heater (“DELTA160V1” manufactured by Ritmo Co., Ltd.). ℃ for 55 seconds. After heating, the heater was removed, and the first resin pipe and the second resin pipe were crimped at a pressure of 1.2 MPa for 2.5 minutes. In this way, a fused pipe was produced in which the first resin pipe and the second resin pipe were connected by butt fusion.

(Comparative Example 4)
A fusion spliced tube was obtained in the same manner as in Example 4, except that a 200A cheese having dimensions shown in Table 1 was used as the first resin tube.

In the fused tubes obtained in Examples 1 to 4 and Comparative Examples 1 to 4, an inner peripheral bead is formed on the inner peripheral surface of the connecting portion between the first resin tube and the second resin tube, and An outer peripheral bead was formed on the outer peripheral surface of the connecting portion. The inner peripheral bead and the outer peripheral bead had a first convex portion on the first resin pipe side and a second convex portion on the second resin pipe side.

In addition, the following dimensions were measured for the spliced tubes obtained in Examples 1 to 4 and Comparative Examples 1 to 4.

Bead width of the inner bead Maximum inner diameter at the end of the first resin pipe in the region R1a Maximum inner diameter at the end of the second resin pipe in the region R2a Maximum height position of the first protrusion of the inner bead The inner diameter of the first resin pipe at the inner diameter of the second resin pipe at the maximum height position of the second protrusion of the inner peripheral bead

(evaluation)
(1) Equivalent pipe length A third resin pipe (straight pipe) and a fourth resin pipe (straight pipe) for connecting to the obtained fusion pipe were produced. A third resin pipe was connected to the upstream side of the fused pipe obtained, and a fourth resin pipe was connected to the downstream side. A pressure gauge A was attached at a position two times the outer diameter of the fusion tube on the upstream side from the joint between the fusion tube and the third resin tube. A pressure gauge B was attached at a position six times the outer diameter of the fusion tube on the downstream side from the joint between the fusion tube and the fourth resin tube. A predetermined flow rate of water was added from the third resin pipe side to the pipe comprising the obtained third resin pipe, the fused pipe (the first resin pipe and the second resin pipe), and the fourth resin pipe. flushed. At this time, from the pressure difference between the pressure observed by the pressure gauge A and the pressure observed by the pressure gauge B, the equivalent pipe length was calculated. The equivalent pipe length can be compared between Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, and Example 4 and Comparative Example 4, which use members of the same shape. Note that the smaller the equivalent pipe length, the smaller the pressure loss.

(2) Breaking water pressure test A water pressure was applied to the obtained fusion tube at a pressure rise rate of 6.7 MPa in 1 minute, and the water pressure (breaking water pressure) until cracks occurred in the tube was determined.

[Judgment Criteria for Breaking Water Pressure Test]
○: breaking water pressure is 6.7 MPa or more ×: breaking water pressure is less than 6.7 MPa

The construction of the fusion tube and the results are shown in Table 1 below.

Further, when a constant water pressure is applied to the obtained fusion pipes, the fusion pipes obtained in Examples 1 to 4 show a higher flow rate than the fusion pipes obtained in Comparative Examples 1 to 4. rice field.

DESCRIPTION OF SYMBOLS 1... 1st resin pipe 1a... 1st convex part 1b... 3rd convex part 2... 2nd resin pipe 2a... 2nd convex part 2b... 4th convex part 3... Inner circumference bead 4... Outer circumference Bead 10... fusion tube H... heater

Claims (9)

connecting the end of the first resin pipe and the end of the second resin pipe by fusion to obtain a fusion pipe;
The first resin pipe is a joint main body, the second resin pipe is a sleeve pipe,
The ratio of the inner diameter at the end face of the first resin pipe before connection to the inner diameter at the end face of the second resin pipe before connection is 1.02 or more and 1.15 or less,
In the step of obtaining the fused tube, an inner peripheral bead is formed on an inner peripheral surface of a connecting portion between the first resin tube and the second resin tube, and the inner peripheral bead is formed on the first resin tube. and a second convex portion on the side of the second resin pipe, and the inner diameter of the first resin pipe at the maximum height position of the first convex portion is 2. A method of manufacturing a fusion-bonded tube, wherein the fusion-bonded tube is obtained such that the inner diameter of the second resin tube is larger than the inner diameter of the second resin tube at the maximum height position of the second protrusion. 2. The method of manufacturing a fusion tube according to claim 1 , wherein at least one of said first resin pipe and said second resin pipe has a portion with a bending angle of 45 degrees or more and 135 degrees or less. 3. The method of manufacturing a fusion pipe according to claim 1, wherein at least one of said first resin pipe and said second resin pipe has a flange receiving portion. A fusion pipe in which a first resin pipe and a second resin pipe are connected by fusion,
The first resin pipe is a joint main body, the second resin pipe is a sleeve pipe,
An inner peripheral bead is formed on an inner peripheral surface of a connecting portion between the first resin pipe and the second resin pipe,
The inner peripheral bead has a first convex portion on the first resin pipe side and a second convex portion on the second resin pipe side,
The maximum inner diameter at the end of the first resin pipe in the region where the inner peripheral bead is not formed is the maximum inner diameter at the end of the second resin pipe in the region where the inner peripheral bead is not formed is 1.02 or more and 1.15 or less,
A spliced tube, wherein the inner diameter of the first resin pipe at the maximum height position of the first projection is larger than the inner diameter of the second resin pipe at the maximum height position of the second projection. The ratio of the inner diameter of the first resin pipe at the maximum height position of the first protrusion to the inner diameter of the second resin pipe at the maximum height position of the second protrusion is 1.02 or more. 5. The fusion tube of claim 4 , which is less than or equal to 0.20. The ratio of the maximum inner diameter at the end of the first resin pipe in the region where the inner peripheral bead is not formed to the inner diameter of the first resin pipe at the maximum height position of the first protrusion is 1. 6. The fusion tube according to claim 4 or 5 , which is between 0.02 and 1.15. The ratio of the maximum inner diameter at the end of the second resin pipe in the region where the inner peripheral bead is not formed to the inner diameter of the second resin pipe at the maximum height position of the second protrusion is 1. 7. The fusion tube according to any one of claims 4 to 6 , which is 0.02 or more and 1.18 or less. The fusion according to any one of claims 4 to 7 , wherein at least one of said first resin pipe and said second resin pipe has a portion with a bending angle of 45 degrees or more and 135 degrees or less. Attached. The fusion tube according to any one of claims 4 to 8 , wherein at least one of said first resin pipe and said second resin pipe has a flange receiving portion.

Images