JP2721449B2 - Electric fusion plastic pipe fittings - Google Patents

Abstract

PURPOSE:To fabricate a large bore pipe fitting without use of any large-size injection molding machine by forming a connection member from thermoplastic material where electric heater wires are embedded under the inside surface of a cylinder, and joining this connection member with an adjoining connection member of the same construction by means of fusion attachment with heat into a single piece. CONSTITUTION:Connection members 10, 11 fitted at the two ends with embedded connector pins 13, 14 as protruding at the outer faces where electric heater wires 21 are embedded spirally under the inside circumference having such an inside diameter as admitting insertion of a plastic pipe to be connected are formed individually by an injection molding machine from a thermoplastic material using a die. The two connection members 10, 11 are pressed to the two sides of a heat plate 20, and current is fed to the electric heater wires embedded in this heat plate 20 so that the end faces 15, 16 of the connection members 10, 11 are melted. followed by removal of the heat plate 20, and the two members 10, 11 are connected into a single piece by fusion attachment with heat by pressing the end faces 15, 16 to each other. Thus a specified pipe fitting is fabricated. This method allows manufacturing a pipe fitting of large bore without requiring the use of any large-size injection molding machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

2. Description of the Related Art There is an electrofusion type plastic pipe joint shown in FIG. 3 disclosed in Japanese Patent Application Laid-Open No. 2-30508. In this example, a heating wire 2 is embedded from one end to the other end on the inner peripheral side of the joint body A, and both ends of the heating wire 2 are connected to connector pins 6 provided at both ends of the body A.

[0002] This type of pipe joint is usually formed by injection molding a molten resin in a mold. For connection, plastic pipes P, P are inserted into the inner surfaces of both ends of the main body A, and a substantially constant output voltage is applied to the connector pins 6 from the controller to cause the heating wire 2 to generate heat.
At the same time.

[0003]

In the conventional plastic pipe joint described above, when the diameter of the joint body A to be connected becomes large, a large mold and an injection molding machine having a large injection capacity are required for molding the joint body, and the molding operation is also required. Molding time is prolonged due to the heat capacity of the main body plastic, resulting in difficulty.

Also, in the connection work with the plastic pipe P, since the pipes P, P inserted on both sides of the joint body A are fusion-spliced at the same time, the heat generation area becomes large, and the power capacity of the controller for energizing the heating wire 2 Also need a big one. That is, the power capacity W of the controller is the current I * voltage E, and the electric energy J given to the heating wire is the current I *
Although the voltage E * is the time T, if the time T for energizing the heating wire is too large or too small, a proper connection state with the pipe cannot be obtained. There is an appropriate energization time T from the relationship between the heat transfer between A and the plastic tube P.

For this reason, a large power capacity W of the controller is required in accordance with the electric energy J. Furthermore, in the case of pipe joints with different diameters of connection ports, since the pipes inserted on both sides are connected simultaneously, the electric energy on the large diameter side of the joint body becomes insufficient or the electric energy on the small diameter side becomes excessive. It was difficult to connect the pipes on both sides with proper connection.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and can form even a pipe joint having a large diameter of a joint body without using a large injection molding machine, and without using a controller having a large capacity for connection. The present invention provides a plastic pipe joint that can be fusion-spliced with the same and can be fusion-spliced with an appropriate electric power according to the connection diameter.

[0007]

The gist of the present invention is that a heating wire is buried on the inner peripheral side of a cylindrical shape into which a connecting plastic tube is inserted, and both ends of the heating wire are connected to connector pins projecting to the outer surface. Two connecting members made of a thermoplastic material are provided, and one end surface of each connecting member is applied to a hot plate heated by a heater to be heated and melted, and the end surfaces of the heated and melted connecting members are mutually joined. Compression bonding and heat fusion bonding,
It is an electric fusion type plastic pipe joint characterized by being integrated.

[0008]

According to the present invention, a heating wire is buried on the inner peripheral side.
Since one end surface of each of the connecting members is applied to a heated hot plate to be heated and melted, and the two are thermally fused and joined to form an integrated pipe joint, especially a large-diameter pipe joint is used. The production can be facilitated without using an injection molding machine or a mold having a large injection capacity, and the molding operation at the time of injection molding can be easily performed. Also, in connection with plastic pipes, since connection work can be performed by energizing the heating wire of the connection member for each connection port of the pipe joint, connection can be performed without preparing a conventional large-capacity controller. Since electric power can be supplied according to the diameter of the pipe, a proper connection state can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numerals 10 and 11 denote connection members obtained by separately molding. The connection members 10 and 11 have an inner diameter into which plastic pipes 50 and 51 to be connected can be inserted, and have a cylindrical shape on the inner peripheral side. The heating wire 12 is helically embedded. Connector pins 13 and 14 projecting outward are embedded at both ends of the connection members 10 and 11, and both ends of the heating wire 12 are connected to the connector pins 13 and 14. The connecting members 10 and 11 are usually formed by injecting a thermoplastic material into a mold by an injection molding machine.

The end faces 15 and 16 of the connection members 10 and 11 thus obtained are applied to the hot plate 20. Since the heating plate 20 has a heater 21 inside, the end faces 15 and 16 are heated and melted. When it reaches the molten state, remove the hot plate 20,
The respective end faces 15, 16 are quickly pressed against each other.
Since the end faces are in a molten state with each other, the two connection members 10 and 11 are integrated by heat fusion bonding. As described above, the socket-type electro-fusion type plastic pipe joint as shown in FIG. 2 is formed. Beads 17 and 18 at the time of fusion are projected from the inner surface side and the outer surface side to the heat fusion bonding portion.
Serves as a stopper when the plastic pipes 50 and 51 are inserted into the pipe joint.

In connection with the pipe, a plastic pipe 51 is inserted into one end of the joint body as shown in FIG. . Since the heating wire 12 is one system on one side of the joint body on the insertion side of the plastic pipe 51, the heating area is half that of the one that generates heat simultaneously on both sides, so that the power capacity of the controller can be reduced to about half. The appropriate fusion splicing can be performed according to the diameter and the connection conditions.

[0012]

As described above, the electro-fusion type plastic pipe joint of the present invention is obtained by integrally connecting the connecting members by heat-sealing, and therefore does not require an injection molding machine having a large injection capacity. In connection with a plastic tube, a controller having a small power capacity can be connected to a large-diameter plastic tube. Further, fusion splicing in a proper connection state with the plastic tube can be performed with electric energy according to the diameter.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which respective connection members of an embodiment are thermally fused to each other.

FIG. 2 is a partial cross-sectional view showing a state when the plastic pipe of the embodiment is connected.

FIG. 3 is a cross-sectional view of a plastic pipe joint showing a conventional technique.

[Explanation of symbols]

 1, pipe joint body 2 hot plate 3 controller 10, 11, connection member 12 heating wire 13, 14, connector pin 20 heater 15, 16, end face of connection member 17, 18, bead 50, 51 plastic pipe

Claims (1)

(57) [Claims] 1. A connecting plastic pipe heating wire embedded in a cylindrical inner circumferential side interpolate, the connecting members at both ends of the electrical heating wire is made of a thermoplastic material which is connected to the connector pins projecting to the outer surface 2 pieces provided, one 該夫's connecting member
The end face of the heater against the hot plate heated by the heater and melted by heating.
The end faces each other of the heating molten respective connecting members and pressed together by heat bonding, electrical fusion, characterized in that integrated
Wearable plastic fittings.