JPH03260490A - pipe fittings - Google Patents

Abstract

PURPOSE:To provide a pipe fitting suitable for joining pipes having a relatively small wall thickness by forming an insert to be pressed to the joined pipes in such an arrangement that it consists of a plurality of rings held at a certain spacing with the aid of retainers. CONSTITUTION:A cylindrical driver 1 is made of a shape memory alloy in stainless steel series, while an insert 2 is formed from a plurality of rings 3 of stainless steel which are held at a certain spacing with the aid of retainers 4 interposed between. If the wall thickness of each pipe 10 is represented by (t), the dia. of each ring 3 shall range 1-3t and the thickness of the driver 1 range 2-5t. As a driver the insert 2 is fitted in the cylindrical member 1, and the pipes 10 are inserted from the two sides. The rings are compressed by thermal contracting the dia. of the driver 1 so that they bite into the peripheries of the pipes 10. Thus the peripheries of the pipes 10 are deformed to contribute to prevention of being drawn off, and also sealing is provided by metal touching with the inner surfaces of the rings 3.

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. This is constructed by providing a plurality of annular protrusions 12 on the inner tightening surface of a cylindrical joint 11. Then, insert the pipe ends of the pipe 10 to be connected from both ends of this joint 11,
By raising the temperature of the joint 11 above the transition temperature, the diameter of the joint is reduced and the annular protrusion 12 bites into the outer surface of the pipes to be connected, thereby connecting the pipes 10 in a fluid-tight manner.

Further, as shown in FIG. 6, an insert 21 having a plurality of annular protrusions 22 formed on the inner surface is interposed between the cylindrical member 2o made of a shape memory alloy and the connected pipe 1o, and the cylindrical member There is a pipe joint that connects the pipes 10 in a fluid-tight manner by reducing the diameter of the pipe 20 and pressing the insert 21 against the pipe to be connected, thereby causing the annular protrusion 22 to bite into the outer surface of the pipe to be connected.

[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.

Furthermore, the insert 21 also requires machining to form 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 has been 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.

[Means for Solving the Problems] The pipe joint of the present invention uses a cylindrical member made of a shape memory alloy as a driver, and presses an insert interposed between the driver and the pipe to be connected to the pipe to be connected. A pipe joint for connecting pipes, characterized in that the insert is a ring member with a plurality of rings held at intervals by a retainer, or the insert is a coil member with closed rings at both ends. It is something.

[Operation] By pressing each ring of the insert composed of a plurality of rings against the pipe to be connected using a cylindrical member made of a shape memory alloy as a trino, the pipe to be connected is deformed by the ring, and the ring becomes a pipe. It is possible to achieve sealing performance by touching the metal to the metal, and also to obtain sufficient tightening amount to prevent pull-out. .

Further, when the insert is a coil member having closed rings at both ends, pulling out is prevented in the same manner as described above, and sealing performance is ensured by the closed rings at both ends.

[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 cylindrical driver 1 is made of stainless steel (9Cr-14Mn-
5N 1-6S i-remaining Fe) shape memory alloy.

The insert 2 is also made of stainless steel, and the spacing between the rings 3 is maintained by interposing a retainer 4 between the rings 3. Further, the outer peripheral surface of the ring 3 is lined with a low melting point metal or resin 8.

If the wall thickness of the connected pipe 10 is t, then the ring 3
The diameter of the driver 1 is 1 to 3 t, and the thickness of the driver 1 is 2 to 5 t.

The insert 2 is attached to the cylindrical member 1 as a driver, and the pipe to be connected 10 is inserted from both sides. Then, by heating and reducing the diameter of the driver 1, the ring 3 is attached to the connected pipe 1.
It is compressed so as to bite into the outer peripheral surface of 0. In this way, as shown in FIG. 1, the outer circumferential surface of the connected tube 10 is deformed to prevent it from being pulled out, and also to achieve a seal by making metal contact with the inner surface of the ring 3.

Note that the cross-sectional shape of the ring is not limited to the circular shape as in the above embodiment, but may be a ring 3a having a rectangular cross-section as shown in FIG. In this case, the inner peripheral edge of the ring comes into metal contact with the connected pipe 10, and the outer peripheral edge of the ring partially bites into the inner peripheral surface of the driver 1, causing the surface finish of the inner surface of the driver 1 to deteriorate. It can be made unnecessary.

In addition, the insert has a coil material 6 as shown in FIG.
The coil member 5 may have closed rings 7 at both ends.

A low melting point metal or resin 8 is provided on the outer peripheral surface of the closed ring 7.
Or lined.

In this case as well, in the same manner as described above, pulling out is prevented and sealing performance is ensured by the closing rings 7 at both ends.

In addition, in the above embodiment, the case where the insert is provided outside the pipe to be connected and the diameter of the driver is reduced to connect the pipe is explained. It can also be applied when connecting.

[Effects of the Invention] The pipe joint of the present invention is as described above, and the wall thickness of the shape memory alloy 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.

[Brief explanation of drawings]

Fig. 1 is a half cross-sectional view showing an example of the pipe joint of the present invention in use, Fig. 2 is an explanatory view showing an example of the insert, and Fig. 3 is a half cross-sectional view when using an insert of another shape. FIG. 4 is an explanatory diagram of another insert, FIG. 5 is a sectional view of a conventional shape memory alloy joint, and FIG. 6 is a sectional view showing a pipe joint in use when a shape memory alloy is used as a driver. 1... Cylindrical driver 2... Ring insert 3.
...Ring 4...Retainer 5...Coil insert 6...Coil material 7...Closing ring.

Claims (1)

[Claims] 1) A cylindrical member made of a shape memory alloy as a driver,
In a pipe joint that connects pipes by pressing an insert inserted between the driver and the pipe to be connected, the insert is formed into a plurality of rings, the intervals of which are held by a retainer. A pipe joint characterized by: 2) The pipe joint according to claim 1, wherein the insert is a coil member with closed rings at both ends.