JPH0343514B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a composite pipe suitable for long-distance axial transport of fluids such as hot water and pressurized gas, particularly 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. The outer layer pipe bears the burden of damage resistance, and the outer layer pipe bears the burden of trauma resistance, so it is attracting attention as being suitable for long-distance transportation of fluids.

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, to avoid damaging the inner surface of the lead pipe 11, use, for example, a nylon tube expander to expand the exposed portion in a substantially vertical direction to form a flange portion, and join the flange portion through 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 4B shows a reinforcing layer 4 formed by sufficiently caulking the expanded flange of a lead pipe joined through packing 6 as shown in Figure A above, and wrapping an epoxy resin-impregnated glass tape around its outer periphery. It is.

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. Expose a lead pipe, insert the exposed lead pipe into a connecting lead pipe that has an inner diameter larger than the outside diameter of the lead pipe, and connect by applying a sealing means between the lead pipe and the connecting lead pipe. It is in.

(Example) FIG. 1 and FIG. 2 are both longitudinal cross-sectional views showing 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.
expose. At this time, when the composite pipe 1 is a corrugated pipe, the exposed lead pipe 11 is smoothed. Next, this exposed lead pipe 11 is inserted into the connecting pipe 2 having an inner diameter larger than the outer diameter of the pipe 11 via the packing 3, and is tightened from the outside of the connecting pipe 2 using a half jig. Connect packing 3 tightly. A reinforcing layer 4 is provided on the outer periphery of the connecting pipe 2 to cover the end of the outer layer pipe 12 and is wrapped with an epoxy resin-impregnated glass tape in the same manner as in the prior art to form a connecting portion.

The connection part in FIG. 2 is made by inserting the exposed lead pipe 11 into the connecting lead pipe 2 by removing the outer layer pipe 12 at the end, as in FIG. Connect the lead pipe 11 by welding 5,
On its outer periphery, a reinforcing layer 4 is formed by winding an epoxy resin-impregnated glass tape as in the conventional case.

In addition, as the connecting pipe 2, in addition to an extruded pipe, a pipe formed by forming a plate-shaped lead into a cylindrical shape and welding the joints may be used, and in order to increase the packing effect by tightening in the case of Fig. It is desirable to use lead, which has lower mechanical strength and greater flexibility than the raw lead pipe 11.

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. If there is, and a current flows, connect by welding using metal pipes of the same material.

Furthermore, the connecting pipe 2 is not only a straight pipe as shown in the figure, but also a straight pipe as shown in the figure.
Of course, a three-pronged branch pipe 21 or a cross-shaped branch pipe 22 as shown in FIGS. 3A and 3B can be used.

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

Furthermore, by using a lead pipe for connection that is softer and has lower mechanical strength than the raw lead pipe, the packing effect is increased.

Furthermore, since the method involves inserting the exposed lead pipe into the connecting pipe, it has the advantage that branch connections with 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. Moreover, FIGS. 4A to 4C are all explanatory diagrams of conventional connection methods. 1...Composite pipe, 11...Lead pipe, 12...
... Outer layer 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. , the exposed lead pipe is inserted into a connecting lead pipe having an inner diameter larger than the outer diameter of the lead pipe, and a sealing means is provided between the lead pipe and the connecting lead pipe for connection. How to connect composite pipes. 2. The method of connecting composite pipes according to claim 1, wherein the 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 lead pipe and the connecting lead pipe are connected by welding.