JPS6356646B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a submarine cable, and it is a method for easily knowing the exact location of the submarine cable, regardless of the situation on the ocean floor, when carrying out installation work or maintenance management of the submarine cable. This is an invention related to submarine cables.

Traditionally, the exact location of submarine cables laid on the ocean floor has been done visually by divers or by using tentacles, but when the seawater is cloudy, it is difficult to identify them. Not only that, but as with deep water, the workability of divers was poor, requiring a lot of work time and a large amount of money. Furthermore, if a submarine cable is buried under the seabed, there is no practical way to discover it, and in recent years methods using magnetic sensors have been attempted, but due to the small amount of magnetism in the outer cable, detection may be difficult depending on the depth of the burial. This method is difficult and has the disadvantage that it cannot be distinguished from other buried objects or objects dumped on the ocean floor.

The present invention aims to improve the above-mentioned problems and provide a submarine cable in which the cable can be easily and accurately identified by tracing the laying or buried route of the submarine cable with a magnetic sensor. purpose.

The present invention provides a submarine cable sheathed with anti-corrosion iron wire, in which ferromagnetic powder is uniformly dispersed in the coating of the anti-corrosion iron wire, so that ferromagnetic powder is distributed at predetermined lengths and intervals in the longitudinal direction of the cable. This is an armored submarine cable that enables magnetic identification of the submarine cable by magnetizing the dispersed ferromagnetic powder.

Examples of the present invention will be described below.
Powdered ferromagnetic material of 0.5 to 20 μm, such as barium ferrite or strontium ferrite,
Evenly mixed in plastisol (mixing ratio 5 to
20% by weight) and baked it onto the surface of the iron wire to cover it. This anti-corrosion iron wire was used to sheath the submarine cable using the same method as before. The ferrite-based ferromagnetic material is an insulator, and the ferromagnetic material mixed in the coating is a powder, so it does not have any effect on the anticorrosion effect or the exterior process. As shown in FIG. 1, the thus obtained armored submarine cable could be magnetized with ferromagnetic powder at arbitrary intervals along the length of the cable, for example, in the manner of Morse code.

Magnetization is performed using a magnetization device 1 shown in FIG. That is, 2 is a coil wound around an iron yoke 3 having a magnetic gap 2a, and is configured such that a large current flows instantaneously at arbitrary time intervals from a power source 4. By repeatedly turning on and off the current from the power source 4 while passing through the magnetic gap 2a, it is possible to magnetize the armored wire with a certain signal.

After the submarine cable constructed as described above is laid or buried on the seabed, searching for the submarine cable is carried out using, for example, a proton magnetometer or an optical pumping magnetometer that travels underwater.

The relationship between the magnetic force of the submarine cable, the detection distance of the magnetometer, and the ferromagnetic powder content is shown in FIG. The vertical axis represents the amount of detected magnetism, the horizontal axis represents the detection distance, and curves A, B, and C represent large, medium, and small magnetic powder contents, respectively. The dotted line L is the detection limit, and the area below the dotted line L represents the range that cannot be detected.

As described above, according to the present invention, since the outer wire of the submarine cable is made of iron wire coated with a coating material mixed with a ferrite-based ferromagnetic material, it is possible to magnetize a unique magnetic mark on the submarine cable. This makes it easier to find the submarine cable using a magnetic sensor, and it is possible to accurately distinguish it from other submarine cables, buried objects, or objects dumped on the ocean floor. Moreover, this makes it possible to shorten the construction period, reduce construction costs, and facilitate maintenance management.

Furthermore, since we use a ferromagnetic material with a large coercive force, the magnetic mark will not disappear semi-permanently, and if you want to change the magnetic mark if necessary, you can easily pass it through the magnetizing device again. It is possible to change to

Furthermore, the magnetism of the magnetic mark not only does not affect communication lines with noise, but also has no effect on marine environment pollution.

[Brief explanation of drawings]

Figure 1 shows a submarine cable according to the present invention with magnetic marks magnetized, Figure 2 is a state diagram of the submarine cable being magnetized by a magnetizing device, and Figure 3 shows the amount of detected magnetism, the detection distance, and the magnetic substance content. This is a graph showing the relationship between In the figure, 1 is a magnetizing device, 2 is a coil, 3 is an iron yoke, 4 is a power source, and 5 is a submarine cable.

Claims (1)

[Claims] 1. In submarine cables covered with anti-corrosion iron wire,
Ferromagnetic powder is uniformly dispersed in the coating of the anti-corrosion iron wire, so that the dispersed ferromagnetic powder is magnetized at predetermined lengths and intervals in the length direction of the cable, and An armored submarine cable that enables magnetic identification of cables.