JPH09229280A - Two-layer fusion pipe joint and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure weatherability and resistance to attack by chlorine and greatly reduce manufacturing cost by forming the inner layer of a joint body by first polyethylene having no carbon black and forming an outer layer 16b by second polyethylene having carbon black. SOLUTION: A two-layer fusion pipe joint 10 is used for joining a two-layer polyethylene pipe comprising an inner layer 12a which does not contain carbon black and an outer layer which contain carbon block and include a T shape pipe joint main body having a receiving port 14 toward three directions. The pipe joint body 16 comprises an inner layer 16a formed by first polyethylene having no carbon black and an outer layer 16b formed by second polyethylene having carbon black is formed on the outer surface of the inner layer 16a, which can ensure resistance to attack by chlorine by the inner layer having no carbon black and weatherability by the outer layer having carbon black.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-layer fusing pipe joint and a method for manufacturing the two-layer fusing pipe joint, and in particular, for example, joining a polyethylene two-layer pipe comprising an inner layer having corrosion resistance and an outer layer having weather resistance. The present invention relates to a two-layer fusing pipe joint and a method for manufacturing the two-layer fusing pipe joint.

[0002]

2. Description of the Related Art When a normal polyethylene pipe is exposed on the ground surface and then piped, the surface of the pipe may be deteriorated by sunlight (ultraviolet rays) and the life of the pipe may be greatly shortened. Therefore, conventionally, it has been generally practiced to join a two-layer polyethylene pipe having weather resistance by mixing carbon black in the outer layer with a metal joint having weather resistance for piping.

[0003]

The conventional metal joints used for joining polyethylene two-layer pipes are excellent in weather resistance and chlorine resistance required for passing tap water, but are expensive metals. Since the material is used, there is a problem that the cost is high. Therefore, the main object of the present invention is to provide an inexpensive joint having weather resistance and chlorine resistance.

[0004]

A first invention is a pipe including an inner layer made of a first polyethylene not containing carbon black and an outer layer made of a second polyethylene containing carbon black. A fitting body, at least one receptacle formed in the inner and outer layers of the fitting body,
A two-layer fusing pipe joint including a fusing heater embedded in a receiving port.

A second aspect of the present invention is a pipe joint body, which includes an inner layer made of the first polyethylene not containing carbon black and an outer layer made of the second polyethylene containing carbon black. Is a two-layer fusing pipe joint including at least one port formed by the outer layer of the above, and a fusing heater embedded in the port. A third invention is (a) forming an inner layer including at least one receiving port, (b) mounting a fusing heater on the outer periphery of the receiving port in the inner layer, and (c) forming an outer layer on the outer surface of the inner layer, It is a manufacturing method of a two-layer fusing pipe joint.

In a fourth aspect of the invention, (a) an inner layer is formed, (b) heaters for fusing supported by a supporting member are arranged side by side at the ends of the inner layer, and (c) an outer layer is formed on the outer surface of the inner layer. This is a method for manufacturing a two-layer fusion tube fitting, in which a single-layer receptacle for incorporating a fusion heater is formed in the outer layer.

[0007]

In the first and second inventions, chlorine resistance is obtained by the inner layer formed of the first polyethylene containing no carbon black, and the outer layer formed of the second polyethylene containing carbon black. Weather resistance is obtained. At the time of joining the pipes, the pipes are inserted into the receiving ports, and the fusing heater mounted in the receiving ports generates heat to fuse the joining surfaces.

In the third aspect of the invention, since the heater is attached to the outer periphery of the receiving opening in the inner layer, when the heating wire is used as the heater, the receiving opening can be used as it is as a mat for winding the heating wire. According to the fourth aspect of the invention, since the receiving opening made of a single layer is formed by the outer layer, the fusing heater can be arranged close to the inner surface of the receiving opening, that is, the bonding surface.

[0009]

According to the first to fourth aspects of the present invention, weather resistance and chlorine resistance can be secured, and the manufacturing cost can be greatly reduced. Further, according to the fourth aspect of the present invention, since the heater for fusing can be arranged close to the joint surface, the fusing efficiency can be improved. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0010]

EXAMPLE A two-layer fusing pipe joint 1 of this example shown in FIG.
0 is for joining the polyethylene two-layer pipe 12 including the inner layer 12a containing no carbon black and the outer layer 12b containing carbon black, and the cheese having the receiving port 14 opened in three directions. Shaped pipe fitting body 1
6 inclusive.

The pipe joint body 16 is an inner layer 16a made of a first polyethylene containing no carbon black.
The outer layer 16b is formed on the outer surface of the inner layer 16a by the second polyethylene mixed with carbon black. Then, the socket 14 is formed by the inner layer 16 a and the outer layer 16 b of the pipe joint body 16, and the inner layer 1 in the socket 14 is formed.
Between the 6a and the outer layer 16b, a heating wire 18 as a heater for fusing is arranged. Both ends of this heating wire 18 are the outer layer 1
It is exposed from the outer surface of 6b.

In manufacturing the joint 10, first, as shown in FIG. 2, an inner layer 16a is formed by injection molding of a first polyethylene, and subsequently, as shown in FIG.
Using the socket 14a formed by 6a as a mat,
A heating wire 18 is spirally wound around the outer circumference. Then, the inner layer 16a is set in an injection molding die, and the second polyethylene is injected onto the outer surface of the inner layer 16a to form the outer layer 16b.

When the two-layer pipe 12 is joined using the joint 10, as shown in FIG. 1, the end of the two-layer pipe 12 is inserted into the receiving port 14 and the receiving port 14 and the two-layer pipe 12 are inserted. And are fixed by a clamp member (not shown). Then, a power supply device (not shown) is connected to both ends of the heating wire 18 exposed from the outer surface of the outer layer 16b, and the heating wire 18 is energized. Then, the heating wire 18 generates heat, and the joint surface between the receiving port 14 and the two-layer pipe 12 is heated and melted and fused. When the predetermined energizing time has passed, the heating wire 1
After removing the power supply device (not shown) from 8 and cooling the fused portion, the clamp member (not shown) is removed.

According to this embodiment, chlorine resistance can be secured by the inner layer 16a containing no carbon black, and weather resistance can be secured by the outer layer 16b containing carbon black. Moreover, since the relatively inexpensive polyethylene is used, the cost can be reduced. Further, since the receiving opening 14a formed of the inner layer 16a is used as a winding mat and the heating wire 18 is wound around the receiving opening 14a, the integral body is set in the mold.
The number of steps is small and it can be easily manufactured.

In the above embodiment, the receiving port 14 is formed at all the connecting ends of the cheese type joint. However, as shown in FIG. 4, for example, at least one connecting end is provided with the connecting port 20. You may form. Further, in the above-mentioned embodiment, the case where the heating wire 18 is used as the heater for fusing is shown.
Instead of this, a magnetic alloy body that generates heat by an electromagnetic induction effect may be used as the fusing heater. As such a magnetic alloy material, various materials as disclosed in JP-A-2-86847 can be used.

In the above embodiment, the receiving port 14a is formed by the inner layer 16a and the heating wire 18 is wound around the receiving port 14a. However, the fusing heater is formed in a predetermined shape in advance. If this is set directly in the injection molding die (core), the receptacle 14 can be formed only by the outer layer 16b, as in the joint 22 shown in FIG. 5, for example. Therefore, in this case, the fusing heater 24 can be arranged close to the inner surface of the receiving port 14, and the fusing efficiency can be improved. In addition, as the heater 24 for fusing in this case, any of the above-mentioned heating wire or magnetic alloy may be used.

In manufacturing such a joint 22, as shown in FIG. 6, first, the inner layer 16a having no receptacle is formed, while the core having an outer diameter larger than the inner diameter of the inner layer 16a is formed. 26 is prepared, and the heater 24 for fusion is directly attached to the outer periphery of the core 26. Subsequently, the fusing heaters 24 supported by the core 26 are arranged side by side at the end of the inner layer 16a.
Then, as shown in FIG. 7, the outer mold 28 is closed to form the cavity 30, the molten polyethylene is injected into the cavity 30, the outer layer 16b is formed on the outer surface of the inner layer 16a, and the heater 24 for fusion is formed. The socket 14 formed of a single layer is formed by the outer layer 16b.

Further, in the above-mentioned embodiments, the case where the present invention is applied to the cheese type joint is shown, but the present invention can be applied to any joint having a socket such as a socket or an elbow.

[Brief description of drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is an illustrative view showing an inner layer of the embodiment in FIG.

FIG. 3 is an illustrative view showing a state in which a heating wire is wound around an outer circumference of a receiving opening of an inner layer.

FIG. 4 is an illustrative view showing another embodiment of the present invention;

FIG. 5 is an illustrative view showing another embodiment of the present invention.

FIG. 6 is an illustrative view showing a manufacturing method in the embodiment in FIG. 5;

FIG. 7 is an illustrative view showing the manufacturing method of the embodiment in FIG. 5;

[Explanation of symbols]

 10, 22 ... 2-layer fusion pipe joint 12 ... 2-layer pipe 14, 14a ... Receptacle 16a ... Inner layer 16b ... Outer layer 18 ... Heating wire 24 ... Fusion welding heater

Claims (4)

[Claims] 1. A pipe joint main body including an inner layer formed of a first polyethylene containing no carbon black and an outer layer formed of a second polyethylene containing a carbon black, the inner layer of the pipe joint main body A two-layer fusing pipe joint comprising: and at least one receptacle formed of the outer layer; and a fusion heater embedded in the receptacle. 2. A pipe joint body including an inner layer formed of a first polyethylene containing no carbon black and an outer layer formed of a second polyethylene containing a carbon black, and the outer layer of the pipe joint body. A two-layer fusing pipe joint, comprising: at least one receiving port formed in 1. and a fusing heater embedded in the receiving port. 3. (a) forming an inner layer including at least one receiving port, (b) mounting a fusion heater on the outer periphery of the receiving port in the inner layer, and (c) forming an outer layer on the outer surface of the inner layer. A method for manufacturing a two-layer fusion bonding pipe joint. 4. (a) forming an inner layer, (b) arranging the fusing heater side by side at the end of the inner layer, (c) forming an outer layer on the outer surface of the inner layer and incorporating the fusing heater therein. A method for manufacturing a two-layer fusion-bonding pipe joint, wherein a single-layer receptacle is formed of the outer layer.