JPH01313749A - Diagnosing method for deterioration of fluid transport pipe - Google Patents

Abstract

PURPOSE:To diagnose the deterioration of a transport pipe by executing an electric conduction to a detecting layer provided with a lead wire like a grating through an electric insulator on a metallic reinforcing layer of a transport pipe and detecting a fact that the lead wire has been disconnected. CONSTITUTION:A fluid transport pipe 1 consists of a plastic inner pipe 2, a metallic reinforcing layer 4 provided with plural metallic lines 3 by butting and winding spirally at a prescribed pitch on said pipe, and an external sheath 5 made of plastic which has been stuck onto the metallic reinforcing layer 4 by an extrusion, etc. On the outside peripheral surface of the metallic lines 3, a detecting layer 9 to which a reinforcing tape 8 which has covered lead wires 6 arrayed like a grating by an electric insulator 7 has been wound spirally is provided. At the time of laying, a lead wire 11 is connected to the detecting layer 9 from both termianl parts 10 of the transport pipe 1 and an electric conduction is executed in advance. When the transport pipe 1 is bent repeatedly and contact parts of the metallic lines 3 have been shifted relatively, the detecting layer 9 is also worn by friction against the metallic reinforcing layer 4, the lead wire 6 is disconnected, and by detecting this disconnection, the deterioration of the transport pipe 1 is diagnosed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for diagnosing deterioration of fluid transport pipes that transport fluids such as crude oil and natural gas.

[Conventional technology]

The fluid transport tube is made by wrapping a plurality of metal strips around a plastic inner tube to provide a metal reinforcing layer and an outer sheath. Since this type of fluid transport pipe is installed and used in the ocean, it is often subjected to repeated bending due to waves.

[Problem to be solved by the invention]

When a fluid transport pipe is repeatedly bent in this way, the contact parts of the metal strips become relatively misaligned, which causes the metal strips to wear out and lose their reinforcing function, causing the fluid transport pipe to break and cause fluid to leak, causing environmental damage. This method has the disadvantage of causing accidents such as contamination and the inability to transport fluids.

[Means to solve the problem]

The present invention relates to a method for diagnosing the deterioration of fluid transport pipes, which eliminates the above-mentioned drawbacks and prevents fluid leakage or accidents in which fluid cannot be transported. A sensing layer in which a plurality of conductive wires are arranged in a lattice shape via an electrical insulator is provided on the metal reinforcing layer of a fluid transport pipe formed by providing a reinforcing layer and an external sheath, and energizing the sensing layer. The present invention is characterized in that it is detected that the conductive wire is cut due to this wear.

[Effect]

As mentioned above, by providing a sensing layer in which multiple conductors are arranged in a lattice shape through an electrical insulator on the metal reinforcing layer and energizing the sensing layer, the fluid transport pipe is subjected to repeated bending due to waves. , when the contact parts of the metal strips are relatively shifted,
The detection layer also wears out due to friction with the metal reinforcing layer, causing all or part of the conductive wire to break. By detecting this breakage by stopping the energization of the detection layer or by increasing its electrical resistance, it is possible to diagnose the deterioration of the fluid transport pipe to see if the metal strips have rubbed against each other and have begun to wear out. It is possible to prevent the strength of the pipe from decreasing and causing an accident.

〔Example〕

Next, one embodiment of the present invention will be explained in detail with reference to the drawings.
What is shown in FIG. 1 is a fluid transport pipe 1 to which the present invention is applied.
Then, there is a plastic inner pipe 2 in which a fluid such as crude oil or natural gas flows and is transported, and on top of the plastic inner pipe 2,
It consists of a metal reinforcement N4 provided by a plurality of metal strips 3 made of stainless steel, for example, wound spirally against each other at a predetermined pitch, and an outer sheath 5 made of plastic applied by extrusion or the like on the metal reinforcement layer 4, On the outer circumferential surface of the metal strip 3, a reinforcing tape 8 (see Fig. 2) in which conducting wires 6 such as copper or aluminum wires arranged in a lattice pattern are covered with an electrical insulator 7 such as polyvinyl chloride or polyethylene is spirally applied. A sensing layer 9 is provided which is wrapped around or stretched vertically. The electrical insulator 7 may be extruded and coated on the outer peripheral surface of the metal strip 3, and the detection layer 9 may be provided thereon separately from the electrical insulator 7.

This fluid transport pipe 1 is used by laying it in the sea, etc. At this time, as shown in FIG. I'll keep it. With this configuration, if the fluid transport pipe 1 is normal, there will be no change in the energization state of the detection layer 9, but if the fluid transport pipe 1 is repeatedly bent by waves, the contact portion of the metal strip 3 will be When the detection layer 9 is shifted, the detection layer 9 is also worn due to friction with the metal reinforcing layer 4, and all or part of the conductive wire 6 is cut. Reference numeral 12 in FIG. 3 indicates a disconnection point where conductor #a6 is completely cut. By detecting this cutting by stopping the energization state of the detection layer 9 or increasing its electrical resistance, it becomes possible to diagnose the deterioration of the fluid transport pipe 1 to see if the metal strips are rubbing against each other and are beginning to wear out. It is possible to prevent the strength of the fluid transport pipe 1 from decreasing and causing an accident.

〔Effect of the invention〕

As described above, the present invention provides a detection layer in which a plurality of conductive wires are arranged in a lattice shape via an electrical insulator on the metal reinforcing layer of the fluid transport pipe, and energizes the detection layer to prevent wear. Since it detects that the conductor wire is cut, it is possible to diagnose the deterioration of the fluid transport pipe to see if the metal strips are rubbing against each other and are beginning to wear out, and if the strength of the fluid transport pipe has decreased. Accidents such as fluid leakage or inability to transport fluid can be prevented from occurring.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a fluid transport pipe to which the present invention is applied;
FIG. 2 is an enlarged sectional view of a reinforcing tape constituting the detection layer, and FIG. 3 is an explanatory diagram showing an embodiment of the present invention. 1-Fluid transport pipe, 2-Plastic inner pipe, 3-Metal strip, 4-Metal reinforcement layer, 5-External sheath, 6-Conductor wire,
7.-electrical insulator, 8-reinforcing tape, 9.-sensing layer, 1
0--terminal section, 11--lead wire, 12--disconnection point. Patent applicant Furukawa Electric Co., Ltd. Figure 2 Figure 3

Claims (1)

[Claims] A metal reinforcing layer is provided by wrapping a plurality of metal strips around a plastic inner tube, and a plurality of conductive wires are placed in a lattice shape on top of the metal reinforcing layer via an electrical insulator, and an outer sheath is provided. 1. A method for diagnosing deterioration of a fluid transport pipe, comprising: providing a detection layer arranged in a row, and detecting breakage of the conductive wire due to wear by applying current to the detection layer.