JPH04265731A - Composite pipe and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a composite pipe, a flowing-down sound of which is lowered when it is used as the vertical main pipe, etc., of a drain pipe for a building, through which a large amount of drain can be flowed down stably without requiring a vent pipe and which has excellent fire resistance, durability and corrosion resistance, and to provide a method, in which the composite pipe can easily be manufactured. CONSTITUTION:At least the internal surface of a metallic pipe 1, on the internal surface of which a spiral projection 12 is formed, is coated with a resin, thus manufacturing a composite pipe, an internal surface of which has a spiral rib, a surface of which is coated with the resin. A mold 92 with a resin pushing core 922 with grooves housing the projection 12 of the internal surface of the metallic pipe 1 at regular intervals is inserted into the metallic band plate while a metallic band plate with the projection 12 in the longitudinal direction is manufactured in a spiral pipe, and the resin is extruded and covered continuously, thus continuously acquiring the composite pipe having said structure.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a composite pipe in which the inner surface of a metal pipe is coated with resin, and a method for manufacturing the same, and in particular to a composite pipe with spiral ribs arranged on the inner surface, which is suitable for use as a vertical main pipe of a building drainage pipe. This invention relates to a composite pipe and its manufacturing method.

0002

[Prior art] Piping materials used for drainage include:
Conventionally, steel pipes, cast iron pipes, etc. have been used, but due to corrosion over many years of use, the pipe body breaks and the pipe line becomes clogged with rust galls, which limits the lifespan of the pipe body. For these reasons, in recent years, composite pipes with excellent corrosion resistance, in which the inner surface of a steel pipe is coated with resin, are being used as drain pipes. Composite pipes with this structure are used as drainage pipe materials for buildings.
Because it is fire resistant, it can be installed in areas where noncombustible materials are required by the Building Standards Act.

On the other hand, vertical drainage main pipes, especially in high-rise buildings, have the problem of high noise when the water flows down, and pressure fluctuations occur when a large amount of wastewater flows, so it is necessary to take up a lot of space for ventilation pipes. There is a problem such as (two-pipe type). As a tube material for solving such problems, a tube material in which spiral ribs are formed on the inner surface of the tube is known, as seen in French Patent Publication No. FR2251673. With this type of pipe material, wastewater flows down in a spiral along the inner wall surface of the pipe, suppressing the sound of flowing water when a small amount of water is being drained, and forming an air core when a large amount of water is flowing, eliminating the need for a ventilation pipe. There are advantages.

[0004] As a method for manufacturing such a tube with inner spiral ribs, a method has been proposed in which a resin tube with inner ribs is extruded and twisted while it is being extruded (Japanese Patent Publication No. 49-42670).

[0005]

[Problems to be Solved by the Invention] By the way, conventional resin inner spiral tubes manufactured by the above manufacturing method have poor impact resistance compared to metal tubes, and have problems such as breakage during transportation and construction. In addition, since it is not fire resistant,
As a pipe for buildings, it has the disadvantage that it cannot be used in fire prevention areas due to the Building Standards Act. The present invention was made in view of the above circumstances, and provides a composite pipe that has a structure suitable for use as a vertical main pipe of a building drainage pipe, and has excellent fire resistance, durability, and corrosion resistance. The object of the present invention is to provide a method that can easily manufacture the composite pipe.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the composite tube of the present invention includes a metal tube in which a spiral protrusion is formed on the inner circumferential surface, at least the inner surface thereof is coated with a resin, Further, the resin of the protrusion-covered portion is characterized by protruding toward the inner surface of the tube along the protrusion to form an inner spiral protrusion.

[0007] In addition, the method for manufacturing a composite pipe of the present invention includes spirally forming a metal strip plate having one or more ridges formed along the longitudinal direction on one surface thereof such that the surface on which the ridges are formed is on the inside. While continuously manufacturing a metal tube by winding the metal strip into a shape and joining the adjacent side edges of the metal strip, the metal tube is inserted into the metal tube from the upstream side in the tube manufacturing direction to the resin pressing core part. It is characterized by inserting a resin extrusion mold in which a groove with a predetermined gap is formed between the spiral protrusions of the metal tube, and extruding molten resin from the mold to coat the inner surface of the metal tube.

[0008]

[Function] The spiral protrusion formed on the inner surface of the tube is
As a vertical drain pipe, it is effective in reducing the sound of flowing water when discharging a small amount of water, and suppressing pressure fluctuations due to the formation of an air core when discharging a large amount of water.Furthermore, covering the inner surface entirely with resin has the advantage of corrosion resistance. In addition, the core of the resin forming the spiral ridges is reinforced with metal ridges, making it highly mechanically durable, and since the outer surface is a metal tube, it becomes a highly fire-resistant tube material. obtain.

[0009] Furthermore, in the manufacturing method of the present invention, spiral protrusions are formed on the inner surface of the obtained metal tube by forming a metal strip having longitudinal protrusions on its surface into a spiral tube. Ru. During the process of making such continuous spiral tubes, when extruding molten resin into the tube, if a groove with a predetermined gap is formed in the resin pressing core with respect to the spiral protrusion on the inner surface of the metal tube, it is possible to The inner surface of the tube is entirely coated with resin in a state that follows the shape of the inner surface including the protrusions, so that it is possible to easily and continuously obtain a composite tube having the above-described structure.

0010

Embodiment FIG. 1 is an external view showing an example of a composite pipe of the present invention. A strip-shaped metal plate (hereinafter referred to as a metal strip) is spirally wound, and the butt portions of the spiral metal tube 1 are welded together.The inner surface of the spiral metal tube 1 has a tube formed at the same spiral angle as the metal strip. A protrusion 12 is formed over the entire length of the metal tube 1, and the inner surface of the metal tube 1, including the protrusion 12, is coated with a substantially uniform resin layer 2, and the entire surface has an inner spiral rib 2a made of resin. It forms a composite tube.

Next, a method for manufacturing a composite pipe having the above structure will be described. FIG. 2 is an overall configuration diagram showing an example of a manufacturing apparatus to which the method of the present invention is applied. The flat metal strip 10 is fed to a forming device 21 for forming a protrusion on one surface thereof, where at least one protrusion 12 extending linearly in the longitudinal direction of the metal strip 10 is continuously formed. is given.

The metal strip 11 on which the protrusions 12 have been formed is then treated by a surface treatment device 31 into a surface condition suitable for adhesion to resin, and then forced into a pipe making device 51 by a drive roll 41. Supplied. As shown in FIG. 3, which is a vertical cross-sectional view in the circumferential direction of the tube, the tube-making device 51 moves a plurality of force rolls 511, . This forced roll 511...
By pushing the metal strip 11 into the inside of the metal strip 511 using the drive roll device 41 so that the surface on which the protrusions 12 are formed faces inside, the outer side of the metal strip 11 is restricted while the both side edges are mutually connected. It has a mechanism that forcibly shapes them into a tubular shape so that they are butted against each other.

As shown in FIG. 3, the metal strips 11 formed into a tubular shape are joined together at their abutted portions by a joining machine 61 to form the metal tube 1. Therefore, the metal tube 1 obtained by the above-described tube manufacturing process has a metal strip 11 on its inner surface.
A spiral protrusion 12 having an angle equal to the helical angle of is formed. On the inner surface of such a metal tube 1,
After being coated with molten resin continuously discharged from a mold 92 as described later, the tube is discharged from the tube making device 51 by a drive device 71 for stably transporting the tube, and cut into a predetermined length by a cutting machine 81. It is severed immediately.

A mold 9 is installed inside the metal tube 1 during the tube manufacturing process.
2 is inserted substantially concentrically with the force rolls 511...511 as shown in FIG. Becomes a tube. That is, an extruder 91 is disposed on the front side of the tube-making device 51, and a mold 92 connected to the extruder 91 is inserted into the metal tube 1 from the upstream side in the tube-making direction. This mold 92 can extrude the molten resin sent from the extruder 91 into a cylindrical shape from a resin discharge port 921 near its tip, and a resin pressing core 922 is further disposed at the tip of the resin discharge port 921. It is provided. This resin discharge port 9
21 and the resin pressing core 922 are located inside the tube making device 51 and behind the opposite edges of the metal strip 11 that are continuously joined.

The resin pressing core 922 has a mold 92 as shown in FIG.
As shown in the partially cutaway sectional view near the tip, a spiral groove 922a is formed to accommodate the protrusion 12 on the inner surface of the metal tube 1 with a predetermined gap. When molten resin is extruded from the resin discharge port 921 using the mold 92 as described above, the resin covers the inner circumferential surface of the metal tube 1 and the outer circumferential surface of the resin pressing core 922. At the same time, the surface portion of the protrusion 12 is also covered with a resin having a thickness corresponding to the gap between the groove 922a of the resin pressing core 922 and the protrusion 12. , this resin adheres to the metal surface to form the resin layer 2 shown in FIG.

[0016] In order to adhesively coat the inner surface of the tube with resin, the heating device 111 may be placed upstream of the tip of the mold, if necessary. Here, if the number of force rolls 511...511 of the pipe manufacturing device 51 is made variable and the position of each roll 511...511 is configured to be movable concentrically, small diameter pipes can be produced with one manufacturing device. It is capable of manufacturing many types of pipes from small diameters to large diameters.

[0017] Materials for the metal strip used in the present invention include steel materials, aluminum and its alloys,
Copper and its alloys, titanium alloys, etc. are applicable. However, when used as a drainage pipe for a building, especially as a pipe passing through a fire prevention zone, the material must pass the Building Standards Act, and if a non-combustible material is not used as the outer layer, steel material must be used. limited to.

The protrusions can also be formed by continuously welding a metal wire to a metal strip, or by continuously bending a part of the width of the metal strip with a roll in the longitudinal direction. Alternatively, a method of continuously shaping a part of the metal strip in the width direction by roll rolling can be adopted. The forming of the protrusions may be carried out on a pipe production line as in the above-described embodiment, or a metal strip plate on which the protrusions have been formed in advance may be used. The number and height of the protrusions may be appropriately selected depending on the type and flow rate of the fluid, and are not particularly limited. An example of the shape or form of the protrusion is shown in FIG. The one shown in Fig. 6 (A) has triangular protrusions T formed on the surface of the metal strip using a roll or the like, and the one shown in Fig. 6 (B) has rectangular metal wires S formed on the surface of the metal strip.
Fig. 3(C) shows a triangular metal wire S' welded to the surface of a metal strip.

[0019] In addition, as a method for making metal pipes, conventional spiral welding pipe making and spiral joint pipe making can be adopted, and these are methods in which the metal pipe is made while rotating. be. If pressure resistance of the pipe body is required,
It is better to use welded steel pipes. In the case of welded pipes, conventional welding methods can be applied; for example, high-frequency resistance welding is suitable when using a hot-rolled steel plate as a metal strip, and TIG welding is suitable when using an aluminium-based material.

The extrusion coating resin can be a thermoplastic resin that can withstand the use of drain pipes and has adhesive properties with metals, such as modified polyolefin, or an adhesive,
Vinyl chloride, polyethylene, etc. can be extrusion coated through the primer layer. Note that the present invention is not limited to the above-described embodiments, and it goes without saying that, for example, the outer peripheral surface of the composite pipe may also be coated with resin.

[0021]

Effects of the Invention As explained above, according to the composite pipe of the present invention, when used as a drainage vertical pipe for a building, the presence of the inner spiral rib 2a allows drainage to flow through the rib 2a.
The water flows down in a spiral pattern, reducing noise when discharging a small amount of water, and suppressing pressure fluctuations by forming an air core when discharging a large amount, allowing stable drainage without the need for ventilation pipes. Become. Moreover, since the inner surface of the metal tube is coated with resin, it has excellent corrosion resistance.
Since the rib 2a is reinforced with a metal rib (projection 12) at its core, the mechanical strength at the rib portion is high, and furthermore, the spiral rib of the metal tube exerts an anchoring effect on the resin in the inner layer. Therefore, since the shrinkage of the resin layer is suppressed, a composite pipe can be obtained in which rust and the like due to exposure of metal at the end of the pipe due to the shrinkage of the resin layer do not occur, and the pipe body has excellent durability.

Furthermore, according to the manufacturing method of the present invention, by spirally forming a metal strip plate having longitudinally extending ridges on one side, metal tubes having spiral ridges on the inner surface can be continuously formed. At the same time, the inner surface of the metal tube is coated with resin, making it easy to create a composite tube with the excellent structure described above.
Moreover, it can be obtained continuously.

[Brief explanation of the drawing]

[Figure 1] External view of the embodiment of the present invention

[Fig. 2] Overall configuration diagram showing an example of a manufacturing apparatus to which the method of the present invention is applied

[Fig. 3] A vertical cross-sectional view showing the pipe making device 51 cut in the circumferential direction of the pipe.

FIG. 4 A partial cross-sectional view of the vicinity of the resin coating mold 92 in an example of an apparatus to which the manufacturing method of the present invention is applied.

[Figure 5]
A partial sectional view near the tip of the resin coating mold 92

[Fig. 6] An explanatory diagram of an example of the shape and form of the protrusion of the composite pipe of the present invention.

[Explanation of symbols]

1...Metal tube 10...Flat metal strip 11...Metal strip plate 12 on which protrusions are formed...Protrusions 2...Resin layer 2a...・Inner spiral rib 21 made of surface resin...
... Forming device 31 ... Surface treatment device 41 ... Drive roll 51 ... Pipe making device 511 ... 511 ... Forced roll 61 ... Bonding machine 71 ... Drive Device 81... Cutting machine 91... Extruder 92... Mold 921... Resin discharge port 922... Resin pressing core 922a... Groove

Claims (2)

[Claims] Claim 1: At least the inner surface of a metal tube having spiral protrusions formed on its inner surface is coated with a resin, and the resin in the portion covered with the protrusions extends along the protrusions toward the inner surface of the tube. A composite tube that protrudes from the inside and forms a spiral protrusion on the inside. Claim 2: A metal strip plate having one or more longitudinal protrusions formed on one surface thereof is wound in a spiral shape with the protrusion forming surface facing inside. While a metal tube is continuously manufactured by joining the side edges adjacent to each other, from the upstream side in the tube manufacturing direction, a resin is pressed into the metal tube in a predetermined manner with respect to the spiral protrusion of the metal tube. A method for manufacturing a composite tube, which comprises inserting a resin extrusion mold in which a groove with a gap is formed, and extruding molten resin from the mold to cover the inner surface of the metal tube.