JPH0343513B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a composite pipe suitable for long-distance transportation of fluids such as hot water or pressurized gas, and in particular, a composite pipe whose inner layer is a lead pipe and whose outer periphery is closely connected to the composite pipe. The present invention relates to a method for connecting composite pipes with a metal or plastic outer layer pipe.

(Prior art) Because of its flexibility, lead pipes are convenient for transporting long objects by winding them around drums, etc., and in manufacturing, they are easy to extrude long objects by using an ordinary extruder. It has the following advantages.

However, when such lead pipes are used for long-distance transportation of hot water, pressurized gas, etc., there are problems with internal pressure resistance and damage resistance due to their softness.

In order to solve these problems, the inventors of the present invention have installed metal pipes such as aluminum pipes and stainless steel pipes, or plastic pipes such as polyvinyl chloride pipes and polyethylene pipes, in close contact with the outer periphery of lead pipes. We have developed a composite pipe with an outer layer pipe. Such composite pipes have the advantage of being moderately flexible and can be transported in drums, and can be easily manufactured using existing equipment. It is attracting attention as a material suitable for long-distance transportation of fluids because the outer layer pipe bears the burden of trauma resistance.

When using the above-mentioned composite pipe for long-distance transportation, it is necessary to connect the pipes, and the inventors have already proposed a connection method as shown in FIGS. 4A to 4C. (See, for example, Japanese Patent Application Laid-Open No. 62-228786.) Figures 4A to 4C are longitudinal cross-sectional views of the upper half of the connection part obtained by the previously proposed connection method.

In FIG. 4A, the outer layer pipe 12 at the end of the composite pipe 1 to be connected is removed to expose the inner layer lead pipe 11. Thereafter, the exposed portion is expanded in a substantially vertical direction using, for example, a nylon expander so as not to damage the inner surface of the lead pipe 11, and a flange portion is formed, and the flange portion is joined via the packing 6. An aluminum flange 7 is attached to the outside of the flange 7, and the connection is made by inserting and tightening bolts.

Figure 4 (b) shows the expanded flange of the lead pipes joined through the packing 6 as shown in the above figure (a), and the reinforcing layer 4 is formed by wrapping an epoxy resin-impregnated glass tape around the outer periphery of the flange. be.

In Fig. 4 C, unlike A and B above, one composite pipe 1 leaves the lead pipe 11 at the end exposed, and only the other composite pipe 1 can be inserted onto the other lead pipe 11. The tube was expanded to
The expanded portion is overlapped with the other lead pipe 11 via packing 6, caulked from the outside, and a reinforcing layer 4 is formed on the outer periphery by wrapping with epoxy resin-impregnated glass tape.

(Problems to be Solved) Among the above-mentioned connection methods that are readily proposed, the type shown in FIG. be. Furthermore, the types shown in FIG. 4 (b) and (c) have the problem that the lead pipe itself is soft and the packing effect of the O-ring is not sufficiently effective.

(Means for Solving the Problems) The present invention provides a method for connecting composite pipes that solves the above-mentioned problems, and is characterized by removing the outer layer pipe at the end of the composite pipes to be connected. Expose the lead pipe, expand the exposed lead pipe until a connecting lead pipe with the same inner diameter as the lead pipe enters, insert the connecting lead pipe with the same inner diameter as the raw lead pipe into the expanded part, and connect the expanded lead pipe with the lead pipe. The purpose is to provide a sealing means between lead pipes for connection or between expanded lead pipes for connection.

(Example) FIG. 1 and FIG. 2 are both vertical cross-sectional views of the upper half of a specific example of a connection portion obtained by the connection method of the present invention.

In the drawing, 1 is composed of a lead pipe 11 and an outer layer pipe 12 such as a lead pipe 11 and a metal pipe such as an aluminum pipe, a stainless steel pipe, or a plastic pipe such as polyvinyl chloride or polyethylene, which is provided on the outer periphery of the pipe in close contact with the lead pipe 11. It is a composite pipe.

The connection part shown in FIG.
is exposed, and the exposed lead pipe 13 is expanded until a connecting lead pipe 2 having the same inner diameter as this is inserted. Next, a connecting lead pipe 2 having approximately the same inner diameter as the raw lead pipe 11 is inserted into the expanded lead pipe 13 via a packing 3 such as an O-ring, and the expanded lead pipe 13 is split in half from the outside. Tighten the packing 3 tightly using a tool. On the outer periphery of the expanded lead pipe 13, a reinforcing layer 4 is provided by wrapping an epoxy resin-impregnated glass tape around the outer layer pipe 12 to form a connecting portion, as in the conventional case.

The connection shown in FIG. 2 is made by inserting a connecting lead pipe 2 having approximately the same inner diameter as the raw lead pipe 11 into the expanded lead pipe 13 as in FIG. 1, and then connecting the lead pipes together by welding 5. On the outer periphery is an outer layer pipe 1
The reinforcing layer 4 is formed by wrapping two layers of epoxy resin-impregnated glass tape.

As the connecting lead pipe 2, in order to increase the packing effect by tightening in the case shown in Fig. 1, it is recommended to use Cu-Te or Sd alloy lead, which has higher mechanical strength and is harder than the raw lead pipe 11. desirable. In addition, in the embodiments shown in FIGS. 1 and 2, the reinforcing layer 4 is provided on the connection part of the lead pipe by wrapping it with an epoxy resin-impregnated glass tape. , and if a current flows, connect by welding using metal pipes made of the same material.

Furthermore, it goes without saying that the connecting lead pipe 2 may be a straight pipe as shown in the figure, or trifurcated or crossed branch pipes 21 and 22 as shown in FIGS. 3A and 3B.

(Experiment example) A composite pipe with an aluminum pipe on top of a lead pipe with an inner diameter of 100 mmφ was created, the aluminum pipe at the end of the composite pipe was removed to expose about 90 mm of the inner lead pipe, and this was expanded using a pipe expansion jig. Inner diameter 110
The tube was expanded to mm. Next, a connecting lead pipe made of hard lead, Pb class 6, was inserted through the O-ring, and then tightened from the outside with a halving jig to bring the O-ring and lead into close contact.

An airtightness test was conducted by applying an internal pressure of 15 kg/cm ² G to such a connection for 3 hours, but no gas leaked from inside.

(Effects of the Invention) According to the above-described connection method of the present invention, the outer diameter of the connection portion is smaller than the conventional connection using a flange, resulting in cost reduction.

Furthermore, the packing effect is increased by using a lead pipe for connection that has high mechanical strength and is hard.

Furthermore, since the method involves inserting lead pipes for connection, it has the advantage that branch connections of three or more prongs can be easily realized.

[Brief explanation of drawings]

Figures 1 and 2 are both vertical cross-sectional views of the upper half of a specific example of a connection part obtained by the connection method of the present invention, and Figures 3A and 3B are diagrammatic illustrations of branch connections. be. FIGS. 4A to 4C are vertical cross-sectional views of the upper half of the connection part according to the previously proposed connection method. 1...Composite pipe, 11...Lead pipe, 12...
...Outer layer pipe, 13...Expanded lead pipe, 2...
... Lead pipe for connection, 3 ... Packing, 4 ... Reinforcement layer, 5 ... Welded connection part.

Claims (1)

[Claims] 1. A method for connecting composite pipes in which an outer layer pipe is provided on the outer periphery of a lead pipe in close contact with the outer layer pipe, in which the outer layer pipe at the end of the composite pipe to be connected is removed to expose the lead pipe. , Expand the exposed lead pipe until a connecting lead pipe with the same inner diameter can fit in, insert the connecting lead pipe with the same inner diameter as the raw lead pipe into the expanded part, and connect the expanded lead pipe and the connecting lead pipe. A method for connecting composite pipes, characterized in that a sealing means is provided between lead pipes or expanded lead pipes. 2. The method for connecting composite pipes according to claim 1, characterized in that the expanded lead pipe and the connecting lead pipe are connected by tightening through packing. 3. The method for connecting composite pipes according to claim 1, wherein the expanded lead pipe and the connecting lead pipe are connected by welding. 4. The method for connecting composite pipes according to claim 1, wherein the expanded lead pipes are connected by welding.