JPH03260495A - pipe fittings - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a pipe joint.

[Prior Art] As a pipe joint made of a shape memory alloy, there is one shown in FIG. 4. This is constructed by providing a plurality of annular protrusions 12 on the inner tightening surface of a cylindrical joint 11. And the fifth
As shown in the figure, by inserting the pipe ends of the pipe 0 to be connected from both ends of this joint 11 and raising the joint 11 above the transition temperature, the diameter of the joint is reduced and the annular projection 12 is
is inserted into the outer surface of the pipes to be connected to connect the pipes 1o in a fluid-tight manner.

[Problems to be Solved] The conventional pipe joint described above requires machining to form the annular protrusion 12 with high precision on the inner surface of the pipe joint 11.

Furthermore, it is necessary to increase the thickness of the shape memory alloy material in order to process the protrusions.

In addition, conventional pipe fittings take into account the connection of thick-walled pipes, and have an annular protrusion that bites into the pipe to be connected to create a seal. However, if the connected pipe is deformed and the amount of tightening is small, sufficient sealing performance may not be obtained.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a pipe joint suitable for connecting relatively thin-walled pipes or pipes made of softer material than the joint material. be.

[Means for Solving the Problems] The pipe joint of the present invention is a shape memory alloy pipe joint that connects a plurality of pipes, the joint shape is made into a corrugated tubular shape, and the contact surface of the corrugated pipe joint with the connected pipe is The pipe material is characterized by being provided with a metal or resin having a melting point lower than that of the pipe material and the joint material.

[Function] A corrugated tubular pipe joint made of a shape memory alloy is raised to a temperature above the transition temperature, and its corrugated portion is pressed against the pipe to be connected, deforming the pipe to be connected, thereby causing the corrugated portion to bite into the pipe and improve sealing performance. and prevents pulling out.

Furthermore, the sealing performance is further improved by softening and solidifying the low melting point metal or resin provided on the contact surface.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings in the case where stainless steel pipes are connected.

The corrugated pipe joint 2 is also made of stainless steel (9Cr-
14Mn-5Ni-6Si-remaining Fe) shape memory alloy.

When the wall thickness of the connected pipe 10 is t, the wall thickness of the corrugated pipe 2 is 1 to 2 t.

First, let's talk about the manufacturing procedure of corrugated tubular pipe fitting 2.
This will be explained from the diagram.

a) The material 1 of the pipe joint is made by, for example, welding a thin material plate, or by drawing and expanding the pipe from the inside and outside after welding.

A material made into a tube by welding is subjected to solution treatment at, for example, 1080°C.

The tube after the solution treatment is straightened and shaped at, for example, 60.0° C., and the shape is memorized.

b) A mold 5 having a U-shaped cross section is continuously arranged outside the shape memory treated pipe material, and both ends are sandwiched between presser plates 6, and the pipe material is formed by an internal hydraulic pressure p and an axial compression load F. Gives processing distortion.

C) In this way, a corrugated pipe joint 2 is manufactured.

A wire-shaped low melting point metal 3 is attached to the corrugated portion of the corrugated pipe joint 2. This low melting point metal is of a soft type and has a melting point of 200 to 250°C.

d) Note that a low melting point metal foil may be attached to the inner surface.

When connecting the pipes, the pipes 10 to be connected are inserted from both sides of the corrugated tubular pipe joint 2, as shown in FIG. Then, by heating and reducing the diameter of the pipe joint 2, the pipe joint 2 tightens the connected pipe 10. In this manner, as shown in FIG. 1, the outer circumferential surface of the connected pipe 10 is deformed and metal-touched with the bottom corrugated part of the corrugated pipe joint 2, thereby creating a seal and generating a pull-out resistance force. The sealing performance is further improved by melting and solidifying the low melting point metal 3.

Further, since some recovery strain remains when touching the metal, a wavy shape remains and a tightened state with high elasticity is obtained as a whole.

Note that the same effect can be obtained by using a thermoplastic resin instead of the low melting point metal.

Also, in the above embodiment, the case where the pipe to be connected is inserted into the pipe joint and the pipe is connected by reducing the diameter of the pipe joint has been described.
Conversely, the pipes may be connected by inserting the pipe joint into the pipe to be connected and expanding the diameter of the pipe joint.

[Effects of the Invention] The pipe joint of the present invention is as described above, and the thickness of the shape-memory metal-containing material can be made thinner than in the past, thereby reducing material costs. Further, since the conventional machining process for forming the annular protrusion is not required, manufacturing costs can be reduced. Furthermore, the sealing performance of the joint can be maintained even when the internal pressure of the pipe changes.

[Brief explanation of drawings]

Fig. 1 is a half sectional view showing an example of the pipe fitting of the present invention in use, Fig. 2 is a half sectional view showing a pipe to be connected inserted into the pipe fitting, and Fig. 3 shows the manufacturing procedure of the pipe fitting. The explanatory drawings, FIGS. 4 and 5, are cross-sectional views showing a conventional shape memory alloy joint and the same in use. 2... Corrugated tubular pipe joint 3... Low melting point metal.

Claims (1)

[Claims] 1) In a shape memory alloy pipe joint that connects a plurality of pipes,
A pipe joint characterized in that the joint shape is a corrugated pipe, and a metal having a melting point lower than that of the pipe material and the joint material is provided on the contact surface of the corrugated pipe joint with a pipe to be connected. 2) The pipe joint according to claim 1, wherein a resin having a melting point lower than that of the pipe material and the joint material is provided on the contact surface of the corrugated pipe joint with the pipe to be connected.