JPH0123017Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a fluid transport pipe for transporting high-pressure water, oil, gas, etc.

Conventionally, steel pipes have been used as fluid transport pipes for transporting high-pressure fluids, but recently, flexible plastic pipes have been used, which can easily adapt to the terrain and are easy to install. This flexible plastic tube is especially advantageous when used near the sea surface or on a rig, where it is affected by waves. Generally, fluid transport pipes of this type consist of a plastic pipe, a metal reinforcing layer provided on the plastic pipe, and optionally a plastic jacket provided on the metal reinforcing layer. The metal reinforcement layer is an internal pressure reinforcement layer formed by spirally wrapping several layers of metal strips to withstand the pressure from the high-pressure fluid flowing inside the plastic pipe, and an internal pressure reinforcement layer that can withstand tension in the axial direction if necessary. In order to achieve this, it consists of a plurality of metal wires or strips at a loose pitch and an axial reinforcing layer placed on top of the internal pressure reinforcing layer. However, in this conventional plastic fluid transport pipe, the internal pressure reinforcing layer is formed by wrapping a metal band at a small pitch, which hinders flexibility, and in order to increase this flexibility, the metal band is wrapped around the inner pressure reinforcing layer. If the material was rolled roughly, there was a risk that some of the material of the plastic pipe would cold flow into the gap between the metal strips and damage the plastic pipe.

It is an object of the present invention to provide a fluid transport pipe which does not impair its flexibility and prevents the material of the plastic pipe from cold flowing into the gap between the metal strips.

The present invention consists of a plastic pipe and a metal reinforcing layer provided on the plastic pipe, and each of the metal reinforcing layers consists of an inner reinforcing layer and an outer reinforcing layer formed by spirally wrapping a metal strip. Although the fluid transport pipe of the present invention is intended for a fluid transport pipe including an internal pressure reinforcing layer, in order to achieve the above purpose, the metal strip of the inner reinforcing layer is wound thinly and tightly, and the outer reinforcing layer is wrapped with an inner reinforcing layer. It is characterized by being thicker and coarsely wound than the metal strip of the layer.

If the metal strip of the inner reinforcing layer of the internal pressure reinforcing layer is tightly wound in this way, even if the internal pressure increases due to high-pressure fluid passing through the plastic pipe, part of the material of the plastic pipe will be trapped in the gap between the metal strips. No cold flow and no damage to plastic pipes. Note that even if the metal strip is tightly wound, its flexibility will not be impaired due to its thin wall thickness.

In addition, if the metal strip of the inner reinforcing layer is thin in this way, the strength of the inner reinforcing layer will be weakened, but since the metal strip of the outer reinforcing layer in the internal pressure reinforcing layer is thick, the strength of the outer reinforcing layer will be reduced. This will compensate for the decrease in the strength of the inner reinforcing layer. Furthermore, since the metal strips of the outer reinforcing layer are loosely wound, their large thickness makes it easy for adjacent metal strips to move with each other as the plastic pipe bends, even if the metal strips themselves have poor flexibility. The difficulty in bending the outer reinforcing layer is eliminated, the flexibility of the internal pressure reinforcing layer as a whole is not inhibited, and the material of the plastic pipe does not flow into the metal band of the internal pressure reinforcing layer (cold flow).

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a fluid transport pipe 10 according to the invention, which comprises a plastic pipe 12.
It consists of a metal reinforcing layer 14 placed on top of the plastic pipe and a plastic jacket 16 placed on top of the metal reinforcing layer.

The metal reinforcing layer 14 is the internal pressure reinforcing layer 14 to be applied later.
A and an axial reinforcing layer 14B, the axial reinforcing layer 1
4B is formed by twisting a plurality of metal wires (for example, steel wires) or metal strips at a large pitch.

As shown in FIG. 2, the internal pressure reinforcing layer 14A consists of inner and outer reinforcing layers 18, 18',
8 is formed by tightly wrapping a thin metal band 20 that does not impair flexibility, and the outer reinforcing layer 18'
It is formed by roughly winding a metal band 20' thicker than zero. Therefore, the flexibility of this internal pressure reinforcing layer is not impaired due to the thinness of the metal band 20 and the loose winding of the metal band 20', and the tight winding of the metal band 20 prevents the flexibility of the plastic pipe 12 from being impaired. The material does not cold flow into the gap between the metal strips 20, and the metal strips 2
A thickness of 0' provides sufficient resistance to internal pressure. In addition, in the illustrated embodiment, the metal band 2
Although the metal strips 20 and 20' have a U-shaped cross section and their legs are interlocked with each other by inner and outer reinforcing layers, these metal strips 20 and 20' may also be flat.

According to the present invention, as described above, a part of the material of the plastic pipe does not flow into the metal band of the internal pressure reinforcing layer, so that the outer surface of the plastic pipe does not have sharp unevenness with a pointed tip. Because it becomes smooth, even if repeated bending force is applied to the transport pipe,
Cracks do not occur from this part, and the plastic pipe can be prevented from being damaged by the pressure of high-pressure fluid. In addition, the material of the plastic pipe has high strength, and if this flows into the metal band of the internal pressure reinforcing layer, the flexibility of the internal pressure reinforcing layer will be impaired, but according to the present invention, the structure of the internal pressure reinforcing layer itself is flexible. Since the transport pipe itself is designed so as not to lose its strength, its flexibility is maintained without reducing the strength of the transport pipe itself. Therefore, even when fluid transport pipes are frequently subjected to repeated bending in areas with rough waves such as the sea or rivers, and high-pressure fluid is transported, there is no damage to the transport pipes or accidents such as fluid leakage in a short period of time. It can provide high-quality, long-life fluid transport pipes.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a fluid transport pipe according to the present invention;
FIG. 2 is an enlarged longitudinal sectional view of the internal pressure reinforcing layer. 10... Fluid transport pipe, 12... Plastic pipe, 14... Metal reinforcing layer, 14A... Internal pressure reinforcing layer, 18, 18'... Inner and outer reinforcing layer, 20, 2
0'...Metal band.

Claims (1)

[Scope of utility model registration request] An internal pressure reinforcing layer consisting of a plastic pipe and a metal reinforcing layer provided on the plastic pipe, each of the metal reinforcing layers consisting of an inner reinforcing layer and an outer reinforcing layer formed by spirally wrapping a metal band. 1. A fluid transport pipe comprising: a metal band of the inner reinforcing layer is thinly and tightly wound, and a metal band of the outer reinforcing layer is thicker and more loosely wound than a metal band of the inner reinforcing layer.