JPH0131243B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a system for immediately detecting abnormalities when submarine cables, submarine water pipes, etc. are hooked on anchors or are hit directly by anchors. This relates to suspended anchor sensing lines installed in necessary locations such as inside submarine cables in order to prevent submarine cable destruction accidents.

[Background of the invention]

Normally, when a submarine cable is damaged by an anchor, etc., it takes a considerable number of days for the cable to be destroyed, so at the time of destruction it is not possible to catch the ship that caused the problem, but when the problem occurs, If it is possible to detect this problem, it will not only be possible to prevent submarine cable destruction accidents as described above, but also make it easier to monitor the ship that caused the problem.

From this point of view, submarine cables with suspended anchor sensing lines, submarine water pipes equipped with suspended anchor sensing lines, and the like have been proposed.

Various types of suspended anchor sensing lines have been proposed, and for example, there is a suspended anchor sensing line having a structure as shown in FIG. 1 in a cross-sectional view. In the example shown in FIG. 1, 1 is an insulating string, such as high-density polyethylene, and three or more insulating strings 1 are twisted adjacently around one central conductor 2. combined,
Outer conductors 3 are arranged in the twisting grooves formed adjacent to these insulator strings 1 and twisted together, an insulating coating 4 is applied on the aggregate, and a watertight compound 5 is placed inside the insulating coating 4. When a force is applied to such a sensing wire from the outside, the outer conductor 3 pushes apart the insulator string 1 and comes into contact with the center conductor 2. If power is applied between the outer conductor 3 and the center conductor 2, the conductor A current flows through the cable, and by monitoring this current, it is possible to sense that force has been applied to the cable.

However, in such sensing wires, the conductor is usually a single metal wire or stranded wire made of copper, steel, stainless steel, etc., but the insulator string is made of plastic such as polyethylene, so there is a difference between metal and plastic. Due to the difference in the tension characteristics of the insulator strings, when they are assembled, the variation in tension of the insulator strings becomes larger than that of metal wires, making it difficult to manage the tension of the insulator strings. Furthermore, as the diameter of the insulator string increases, its cross section tends to deform into an ellipse or the like, and the sensitivity of the sensing wire also deteriorates accordingly. In a sensing line with this kind of structure,
Although it is desired to apply tension to the insulator strings so that they can be tightly packed together, it is also difficult to apply too much tension to the insulator strings as described above due to elongation or residual stress.

The present invention has been made to overcome the drawbacks of the conventional sensing lines mentioned above.

[Summary of the idea]

The present invention involves twisting three or more insulator strings around a center conductor, twisting outer conductors into the twisting grooves of the adjacent insulator strings so as not to contact the center conductor, and collecting these. Summary of a suspended anchor sensing wire comprising an insulator on the outside of the body, the insulating string comprising a tension member and an insulating coating provided outside the tension member. That is.

[Specific description of the invention]

FIG. 2 shows a cross-sectional view of the suspended anchor sensing line of the present invention.
In FIG. 2, 2 is a center conductor, and around the center conductor 2 at least three or more insulator strings 1 are twisted adjacent to each other, and the insulator strings 1 are attached to a tension member 6 with an insulator. 7 is coated. The outer conductors 3 are placed in the twisting grooves formed adjacent to the insulator strings 1 and twisted together, and the outer conductors 3 are kept from coming into contact with the center conductor 2. The sensing wire of the present invention is further provided with an insulating coating 4 on the outside of the assembly of the center conductor 2, insulator string 1, and outer conductor 3, and usually a presser tape 8 is wrapped over the assembly and insulated over it. A coating 4 is provided.

In the present invention, the tension member 6 may be, for example, a metal wire such as annealed copper stranded wire, stainless steel wire, iron wire, or piano wire, or FRP rod (for example, glass fiber, aromatic polyamide fiber, etc. impregnated with epoxy resin and hardened). things) are used. It is preferable that the tension member 6 does not slip at the interface with the insulator 7, and for this purpose, it may be bonded with an adhesive. It is also preferable that the surface of the tension member 6 is textured, since this prevents slipping at the interface between the tension member 6 and the insulator 7. The unevenness on the surface of the tension member 6 may be provided by providing projections or depressions at arbitrary intervals, and it is preferable to use twisted wire as the tension member 6 because the twisting grooves serve as the unevenness. Further, the surface of the tension member may be roughened by mechanical processing such as sand blasting or pressing, or by chemical processing.

Furthermore, the combination of surface irregularities and adhesive is even more effective in preventing slippage at the interface.

As the insulator 7, high density polyethylene, low density polyethylene, crosslinked products of these polyethylenes, ethylene vinyl acetate copolymer, or mixtures thereof,
Resin compositions made by adding inorganic fillers and the like to these resins are used.

〔Example〕

In Fig. 2, the central conductor 2 is a flexible copper stranded wire (30 wires/0.18 mm), the tension member 6 is an annealed copper stranded wire (7 wires/0.8 mm), and the insulator 7 is a high-density polyethylene wire (1.55 mm thick, Outer diameter as insulator string 1
5.5mm), annealed copper wire (2.7mm solid wire) as outer conductor 3
Polyethylene coating (1.5mm thickness) as insulation coating 4
Using each of these, the gap between the above sets was filled with watertight compound 5 to create a hanging anchor sensing wire with an outer diameter of about 15 mm.

The above sensing line was compressed by applying a load to a disk with a diameter of 12.5 mm according to the sensing performance test method shown in Figure 3.
Measure the amount of deformation and load when there is continuity between the center conductor and the outer conductor, that is, when it is sensed, and then remove the load and measure the amount of load and deformation when the insulation between the center conductor and the outer conductor is restored. was measured. In Figure 3, 8 is the sensing wire, 2 is the center conductor, 3 is the outer conductor, 9
is a load, and 10 is a tester for sensing continuity and insulation between the center conductor and the outer conductor.

FIG. 4 is a graph showing the above test results, where the vertical axis shows the load (Kg) and the horizontal axis shows the amount of deformation (mm). In FIG. 4, as a load is applied, the sensing line deforms along curve A, and sensing occurs at point A.
Then, as the load is removed, the deformation recovers along curve B, and the insulation is restored at point a. After the load is completely removed, when the load is applied again, it deforms along curve C and is sensed at point B. As the load is removed, the deformation recovers along curve d, and point b
The insulation is restored at . After the load is removed, when a load is applied again, it deforms along curve E and is sensed at point C. Then, when the load is removed, the deformation is restored along the curve, and the insulation is restored at point c.

As described above, it can be seen that the sensing line of the present invention has sensing ability and recovery property even if load application and load removal are repeated three times at the same location, and there is no change in sensing characteristics.

〔Effect of the invention〕

Since the suspended anchor sensing line of the present invention has the above-described structure, it has the following effects.

(i) Since a tension member is included in the insulator string, variations in the tension of the insulator string are reduced.
Easy to manage tension during manufacturing.

(ii) Since the strength of the insulator string is strong due to the tension member, it is possible to make the twisting tighter, and therefore, it is possible to reduce the variation in sensing ability. Moreover, the strength of the sensing line as a whole can be increased. As a result, reliability during manufacturing and installation can be improved.

(iii) Since the tension member is in the insulator string,
Since the outer diameter of the insulator string is elliptical (particularly when the outer diameter is large), the sensing sensitivity does not vary depending on the situation, and the sensing accuracy of the sensing line is excellent.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional suspended anchor sensing line, Fig. 2 is a sectional view of a suspended anchor sensing line of the present invention, Fig. 3 is a schematic diagram showing a sensing performance test method, and Fig. 4 is a sectional view of a suspended anchor sensing line of the present invention. It is a graph which shows the sensing characteristic of an anchor sensing line. DESCRIPTION OF SYMBOLS 1... Insulator string, 2... Center conductor, 3... Outer conductor, 4... Insulating coating, 5... Watertight compound, 6... Tension member, 7... Insulator, 8
... Hanging anchor sensing line, 9... Load, 10... Tester.

Claims (1)

[Claims] 1. Twisting three or more insulator strings around a center conductor, and twisting outer conductors into the twisting grooves of the adjacent insulator strings so as not to contact the center conductor. , a sensing wire formed by applying an insulator to the outside of these aggregates, the hanging anchor characterized in that the insulator string consists of a tension member and an insulating coating provided outside the tension member. Sensing line. 2. The suspended anchor sensing line according to claim 1, wherein the tension member has an uneven surface. 3. Claim 2 in which the unevenness on the surface of the tension member consists of protrusions or depressions provided at arbitrary intervals.
Hanging anchor sensing line as described in section. 4. The suspended anchor sensing wire according to claim 2, wherein the unevenness on the surface of the tension member is comprised of twisted grooves of twisted wires. 5. The suspended anchor sensing wire according to claim 2, wherein the unevenness on the surface of the tension member is roughened. 6. The suspended anchor sensing line according to claim 1 or 2, wherein the tension member and an insulating coating provided on the outside of the tension member are bonded together with an adhesive.