JPH0755437Y2 - Elbow or Tees type pipe fitting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of use" The present invention relates to an elbow or tees type pipe joint adapted to be connected and fixed by using a shape memory alloy.

“Prior Art” For example, in a hospital or the like, various gases such as oxygen, nitrogen, and laughing gas are used, and therefore, gas pipes for each are made. This pipe is constructed by cutting the pipe to an appropriate length and connecting it at the site. In such piping, it is necessary to use a joint called an elbow bent in an L shape or a joint called a teeth bent in a T shape to make the connection. As the elbow and the tees, generally, a thick metal tube formed by casting is used.

Further, as shown in FIG. 6, for example, when a straight pipe 2 is connected to the end of the elbow 1, the end of the pipe 2 to be connected is inserted into the inner circumference of the end of the elbow 1 to join the two. Was brazed with metal braze 3.

On the other hand, in recent years, various joints have been proposed that can be connected only by heating using a shape memory alloy.

For example, in Japanese Patent Laid-Open No. 172715/1985, one of the connecting pipes is fitted inside or outside the other pipe, and a thermosetting resin is applied to the gap, and a shape memory alloy is formed on the outside. The method of connecting the pipes is disclosed, in which the joint of (1) is attached and the joint of the shape memory alloy is reduced in diameter.

Further, in Japanese Patent Laid-Open No. 62-15677, the ends of the pipes to be connected are each expanded, and an inner pipe is inserted into the inner periphery of the expanded part to connect and the shape is formed on the outer periphery of this connection via a liner. A pipe connecting device is disclosed in which a memory alloy joint is mounted and the shape memory alloy joint is connected by reducing its diameter.

Further, in Japanese Patent Laid-Open No. 2-51690, the pipes to be connected are butted, a shape memory alloy joint is attached to the outer periphery of the pipes via a liner, and solder is applied to the inner peripheral surface of the liner. A pipe joint is disclosed which melts the solder on the inner circumference of the liner when the alloy joint is heated to reduce its diameter.

[Problems to be solved by the device] However, when a conventional elbow or teeth is used for connection by brazing, it is heated to a high temperature of 600 to 800 ° C during brazing, so that the connection part is oxidized and the pipe Metal oxide is generated on the inner circumference. In a gas pipe of a hospital or the like, there is a risk that the above metal oxide may come off during use and enter the human body. The gas pipes are color-coded according to the type of gas, but the paint burns during brazing,
There were also problems such as discoloration of the paint, generation of gas and smoke, and pollution of the environment.

Therefore, it is conceivable that the above elbow or teeth type joint is made of a shape memory alloy, and the connection is made by heating the temperature above the transformation point of the shape memory alloy to reduce the diameter. The shape of the joint is difficult to be made of a shape memory alloy, and even if it is made to have such a shape, it is difficult to perform a memory treatment to a reduced diameter shape, and the cost is significantly high.

Therefore, an object of the present invention is to provide an elbow or tees type pipe joint which can be connected by a simple operation by utilizing the shape restoring force of the shape memory alloy.

[Means for Solving the Problems] In order to achieve the above object, an elbow or tees type pipe joint of the present invention includes an elbow or tees type pipe made of shape memory resin or heat shrinkable resin, and A ring made of a shape memory alloy fixed by being inserted into the inner circumference of the end portion,
A spring member that is attached to the outer circumference of the end of the pipe and applies an elastic force to reduce the diameter of the end of the pipe, and the elbow or teeth type pipe and the ring of the shape memory alloy are heated. It is characterized in that the diameter is reduced when it is performed.

In a preferred aspect of the present invention, it is preferable that unevenness is formed on the outer circumference of the shape memory alloy ring, and the unevenness cuts into the inner circumference of the end portion of the elbow or tees type tube to fix both.

Further, as another aspect, it is preferable that an adhesive agent is interposed between the inner circumference of the elbow or tees type tube and the outer circumference of the ring of the shape memory alloy, and both are fixed by the adhesive agent.

Further, it is preferable that the shape memory alloy ring has a connecting portion inserted into an inner circumference of an end portion of the elbow or tees type tube and a tightening portion protruding from the tube.

[Operation] In the present invention, the end portion of the pipe to be connected is inserted into the shape memory alloy ring inserted into the end portion of the elbow or tees type pipe, and in that state, the temperature above the transformation point of the shape memory alloy is exceeded. When heat-treated at a temperature, the shape memory alloy ring contracts in diameter, and the outer circumference of the pipe to be connected can be clamped and fixed. In this case, the end of the elbow or tees type tube made of shape memory resin or heat-shrinkable resin is also reduced in diameter by heating, and the spring member provided on the outer periphery of the end of the tube elastically tightens the tube. Even if the diameter of the memory alloy ring is reduced, the close contact state between them is maintained.

In this way, since the connection can be made by a simple operation of inserting the end portion of the pipe to be connected and performing heat treatment, it is possible to easily perform gas piping work in a hospital, for example. Further, since the transformation point of the shape memory alloy may be a temperature at which the diameter is not reduced during handling of piping work, it is not necessary to heat the pipe to such a high temperature, and the work can be performed safely. It is possible and the metal of the tube is hardly oxidized.

In a preferred embodiment of the present invention, when the shape memory alloy ring is provided with irregularities and is bite into and fixed to the inner circumference of the elbow or teeth type tube, or the inner circumference of the elbow or teeth type tube and the shape memory alloy When the outer periphery of the ring is fixed with an adhesive, the two can be fixed more airtightly and securely so as not to come off.

Further, when the shape memory alloy ring is projected from the end of the elbow or the teeth type tube to form the tightened portion, the tightened portion is easily heated, and the shape of the shape memory alloy ring is surely restored. be able to.

[Embodiment] FIGS. 1 and 2 show an embodiment of the pipe joint of the present invention.

In this pipe joint 11, rings 13 made of a shape memory alloy are inserted and fixed to the inner circumferences of both ends of a pipe 12 formed of an elbow type made of a shape memory resin, and further, a C-shaped cross section is formed at the outer circumferences of both ends of the pipe 12. The spring member 14 of FIG. In the figure, reference numeral 15 indicates a pipe to be connected.

Here, the shape memory resin is a resin that positively utilizes a characteristic change at temperatures above and below a glass transition point peculiar to a polymer material. It has a high rigidity at a temperature below the glass transition point (glass region), but at a temperature above the glass transition point (rubber region) the rigidity decreases and it becomes rubber-like. When the rubber region is deformed to a desired shape and then cooled to the glass region as it is, the deformed shape is maintained and solidified. When this is heated to the rubber region again, it has the property of returning to the original shape memorized at the time of molding.

Examples of the shape memory resin include polynorbornene (manufactured by Nippon Zeon Co., Ltd.), styrene-butadiene copolymer (manufactured by Asahi Kasei Co., Ltd.), polyurethane (Mitsubishi Heavy Industries, Ltd.).
Various resins such as those manufactured by the present invention are known, and any of these may be used in the present invention. In this embodiment, polynorbornene (manufactured by Nippon Zeon Co., Ltd.) is used as the material of the tube 12.

On the other hand, the shape memory alloy ring 13 can be formed of a known shape memory alloy such as a TiNi alloy, and has a diameter reduced so as to have an inner diameter smaller than at least the outer diameter of the pipe 15 to be connected. Then, the diameter is expanded at normal temperature and the tube is inserted into the end of the elbow type tube 12. The transformation point of the shape memory alloy may be set to a temperature at which the diameter does not shrink during handling, preferably 100 to 150 ° C.

The shape of the tube 12 made of the shape memory resin is memorized so that the shape memory alloy ring 13 has an inner diameter smaller than an outer diameter when the diameter of the ring 13 is reduced. Further, the glass transition point of the shape memory resin is preferably set so that sufficient rigidity is maintained in the operating temperature range of the pipe, and is set to 100 to 150 ° C. like the transformation point of the shape memory alloy. Preferably.

In this embodiment, an annular unevenness 13a is formed on the outer circumference of the shape memory alloy ring 13, and the unevenness 13a bites into the inner circumference of the elbow type tube 12 and is fixed. For this reason, the shape memory alloy ring 13 is firmly prevented from coming off the elbow-type tube 12, and the airtightness is also maintained excellent. As the unevenness 13a, various shapes such as an annular unevenness, a spiral unevenness, and a mesh-shaped unevenness can be adopted. Furthermore, corresponding to the unevenness of the shape memory alloy ring 13,
Concavities and convexities may be formed on the inner circumference of the elbow type tube 12.

The spring member 14 elastically presses the outer circumference of the elbow-shaped pipe 12, and in this embodiment, a metal spring plate bent in a C-shaped cross section is used. It can also be configured with a spring wire or the like.

When using the pipe joint 11, the end of the pipe 15 to be connected is inserted into the inner circumference of the shape memory alloy ring 13. At this time, the ring 13 has an inner diameter larger than the outer diameter of the tube 15 so that the tube 15 can be easily inserted. In this state, the exposed portion of the shape memory alloy ring 13 and the outer periphery of the end portion of the elbow type tube 12 are heated to form the shape memory alloy ring 13
Is contracted, and the outer circumference of the pipe 15 to be connected is tightened and fixed. At this time, the end portion of the elbow type tube 12 is also reduced in diameter by the shape restoring force of the shape memory resin and the elastic tightening force of the spring member 14, and is brought into close contact with the outer circumference of the shape memory alloy ring 13.

FIG. 3 shows another embodiment of the pipe joint of the present invention.

In this pipe joint 21, a shape memory alloy ring 13 is inserted into the inner periphery of the end portion of the elbow type pipe 12, and the shape memory alloy ring 13 is fixed to the inner periphery of the elbow type pipe 12 via an adhesive layer 22. Other than that, it has the same structure as the above-mentioned embodiment. An adhesive layer is also interposed between the shape memory alloy ring 13 and the pipe 15 to be connected, and when the shape memory alloy is reduced in diameter, the adhesive layer enhances airtightness and fixes it. You may do it.

FIG. 4 shows still another embodiment of the pipe joint of the present invention.

In this pipe joint 31, a shape memory alloy ring 13 is provided with a connecting portion 13b and a tightening portion 13c. Concavities and convexities 13a are formed on the outer periphery of the connection portion 13b, as in the embodiment shown in FIGS. 1 and 2, and this portion is inserted and fixed to the inner periphery of the end portion of the elbow type pipe 12. The tightened portion 13c is thicker and extends outside the elbow-shaped pipe 12. A spring member 14 is attached to the outer circumference of the end of the elbow type tube 12 as in the above embodiment.

In this pipe joint 31, since the tightening portion 13c of the shape memory alloy ring 13 is exposed to the outside, heat is efficiently transferred to the ring 13 when inserting and heating the pipe 15 to be connected. The diameter of the shape memory alloy ring 13 can be reliably reduced. Further, in this embodiment, since the tightening portion 13c is thick, a stronger tightening force can be obtained.

FIG. 5 shows still another embodiment of the pipe joint of the present invention.

This pipe joint 41 is configured such that the rings 13 made of a shape memory alloy are respectively inserted and fixed to the inner circumferences of the ends of the tees type pipe 42 made of a shape memory resin, and the spring members 14 are made to the outer circumference of the end of the pipe 42. It is attached. This pipe joint 41 has a shape memory alloy ring 13 inserted into each of three ends, and a pipe to be connected is inserted into the shape memory alloy ring 13.
The tube can be connected by heating 13 to reduce its diameter. At this time, the diameter of the end of the pipe 42 made of shape memory resin is also reduced, and the spring member 14 assists this, so that the pipe 42 comes into close contact with the outer periphery of the ring 13.

In each of the above embodiments, the shape memory resin is used as the material of the elbow type tube 12 or the tees type tube 42, but a known heat shrinkable resin may be used instead.

[Advantages of the Invention] As described above, according to the present invention, a shape memory alloy ring is inserted and fixed to the inner circumference of the end portion of an elbow or tees type tube made of shape memory resin or heat shrinkable resin. In addition, the spring member was attached to the outer circumference of the end of the pipe so that when the pipe and the ring were heated, the diameters of both of them decreased, so that the end of the pipe to be connected was inserted into the shape memory alloy ring. Then, the connection can be made only by heating and reducing the diameter. In this case, the shape memory alloy ring is reduced in diameter to tighten the outer periphery of the pipe to be connected, and the elbow or tees type pipe is also reduced in diameter and pressed against the outer periphery of the shape memory alloy ring, so that sufficient fixation is achieved. You can gain strength and airtightness. Also, the heating temperature required to reduce the diameter of the elbow or Tee's type tube or the shape memory alloy ring does not need to be so high, so that no metal oxide is formed, and for example, a gas pipe of a hospital. It can be used with confidence. Further, even if the pipe is painted, it is possible to prevent the paint from burning and the paint from discoloring.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a pipe joint according to the present invention,
FIG. 2 is a partial sectional view of the pipe joint, FIG. 3 is a partial sectional view showing another embodiment of the pipe joint according to the present invention, and FIG. 4 is a portion showing still another embodiment of the pipe joint according to the present invention. Sectional view, fifth
FIG. 6 is a partial sectional view showing still another embodiment of the pipe joint according to the present invention, and FIG. 6 is a partial sectional view showing an example of a conventional pipe joint. In the figure, 11, 21, 31, and 41 are pipe joints, 12 is an elbow type pipe, and 13
Is a shape memory alloy ring, 13a is uneven, 13b is a connecting portion, 13
c is a tightening portion, 14 is a spring member, 15 is a pipe to be connected, 22 is an adhesive pipe, and 42 is a tees type pipe.

Claims (4)

[Scope of utility model registration request] 1. An elbow or tees type pipe joint,
An elbow or tees type tube made of shape memory resin or heat shrinkable resin, a ring made of shape memory alloy inserted and fixed to the inner circumference of the end of this tube, and attached to the outer circumference of the end of the tube. And a spring member that applies an elastic force to reduce the diameter of the end portion of the tube, and the elbow or teeth type tube and the shape memory alloy ring are reduced in diameter when heated. Elbow or tees type pipe joint characterized in that 2. The elbow or teeth according to claim 1, wherein irregularities are formed on the outer circumference of the ring of the shape memory alloy, and the irregularities cut into the inner circumference of the end portion of the elbow or the teeth type tube to fix them. Type fittings. 3. An inner circumference of the elbow or tees type tube,
An adhesive is interposed between the shape memory alloy and the outer circumference of the ring, and the two are fixed by this adhesive.
The elbow or tees type pipe joint described. 4. The shape memory alloy ring has a connecting portion inserted into an inner periphery of an end portion of the elbow or tees type tube, and a tightening portion protruding from the tube. The elbow or tees type pipe joint according to any one of 1.