JPH0618424A - Submersion detecting line - Google Patents

Abstract

PURPOSE:To provide a submersion detecting line that is able to detect a submersing position in a highly accurate manner extending over several kilometers in an overall length. CONSTITUTION:An exothermic (or endothermic) covering 5 containing exothermic material (or endothermic material) such as calcium chloride generating heat in reaction with water is further installed on an optical fiber conductor 4 fitted with both primary and secondary coverings 2 and 3 on an optical fiber 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water detection line capable of highly reliable water detection using an optical fiber.

[0002]

2. Description of the Related Art Hitherto, as a water immersion detection sensor, there has been known one in which an optical fiber and an absorption / expansion member which absorbs water and expands it are combined. This is based on the principle that the absorption expansion member expands and bends the optical fiber when there is water so that the transmission loss increases.

However, such a flood detection line is
This is to detect the presence or absence of water in a specific place such as a cable connection portion, and it is impossible to detect at any place and also to identify its position.

There is also known a flooded position detecting method utilizing the change in resistance between two conductors depending on the flooded water, but this method cannot be used under a high electric field and is long. In that case, there is a problem that the accuracy is lowered.

[0005]

As described above, the conventionally known water infiltration detection technology cannot detect at any place, cannot be used in a high electric field, or loses accuracy when it is long. There were difficulties.

Under these circumstances, a so-called distributed temperature sensor is used which utilizes the fact that the intensity of Raman scattered light generated when an optical pulse is incident from one end of an optical fiber changes depending on the temperature of the optical fiber. A so-called temperature measuring device has been developed and is being considered for use in various fields such as temperature monitoring of power cables.

This distributed temperature sensor is capable of measuring the temperature distribution over the entire optical fiber of several kilometers at a time, and if it can be used to detect water intrusion, it can accurately detect even water in remote areas several kilometers away. As a result, it is considered that a highly reliable inundation detection system without the above-mentioned drawbacks can be established.

[0008] Therefore, as a result of extensive research conducted by the present inventor to utilize such a distributed type temperature sensor for water immersion detection, an optical fiber which reacts with the infiltrated water to generate heat or absorbs heat is distributed to the distributed type temperature sensor. It has been found that by combining with, it becomes possible to detect the inundation position with high reliability.

The present invention has been made on the basis of such knowledge, and an object thereof is to provide a flood detection line capable of highly reliable flood detection in combination with a distributed temperature sensor.

[0010]

The inundation detection line of the present invention comprises:
A heat-generating body or heat-absorbing body containing a substance that reacts with water to generate heat or absorb heat is arranged around the optical fiber. As an optical fiber, SM
Type, GI type, or any other conventionally known optical fiber can be used.

Examples of substances that react with water to generate heat include aluminum chloride (AlCl ₃ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), and barium chloride (BaCl ₂ ).
, Beryllium sulfate (BeSO ₄ ), calcium bromide (CaBr
₂ ), calcium carbonate (CaCO ₃ ), calcium chloride (CaC
l ₂ ), calcium hydrogen phosphate (CaHPO ₄ ), calcium iodide (CaI ₂ ), calcium nitrate (Ca (NO ₃ ) ₂ ).
, Calcium hydroxide (Ca (OH) ₂ ), calcium phosphate
_{(Ca 3 (PO 4) 2} ), calcium sulfate (CaSO _4), cadmium chloride (CdCl _2), cadmium fluoride (CdF _2), cadmium sulfate (CdSO _4), cerium chloride (CeCl _3), cobalt chloride (CoCl _2), cobalt sulfate (CoSO _4), copper sulfate (CuSO _4), ferrous chloride (FeCl _2), ferric chloride (FeC
l ₃ ), ferrous sulfate (FeSO ₄ ), ferric sulfate (Fe ₂ (SO
₄ ) ₃ ), magnesium bromide (MgBr ₂ ), magnesium iodide (Mg I ₂ ), magnesium chloride (MgCl ₂ ), magnesium nitrate (Mg (NO ₃ ) ₂ , magnesium sulfate (MgSO 4
₄ ), manganese sulfate (MnSO ₄ ), manganese chloride (MnC 4
l ₂ ), nickel chloride (NiCl ₂ ), aluminum ammonium sulfate (NH ₄ Al (SO ₄ ) ₂ ), strontium bromide (SrBr
₂ ), nickel sulfate (NiSO ₄ ), zinc chloride (ZnCl ₂ ),
Strontium chloride (SrCl ₂ ), zinc sulfate (ZnSO ₄ ),
Zinc fluoride (Zn F ₂ ), aluminum bromide (AlBr ₃ ),
Silver fluoride (AgF), calcium perchlorate (Ca (ClO ₄ ) ₂ )
, Beryllium chloride (BeCl ₂ ), cadmium nitrate (Cd (NO
₃ ) ₂ ), calcium hydrogen phosphate (Ca (H ₂ PO ₄ ) ₂ ),
Cobalt fluoride (CoF ₂ ), cobalt bromide (CoBr), cobalt nitrate (Co (NO ₃ ) ₂ ), cobalt iodide (CoI),
Copper nitrate (Cu (NO ₃ ) ₂ ), copper chloride (CuCl ₂ ), iron iodide
(Fe I ₂ ), Iron bromide (FeBr ₂ , FeBr ₃ ), Hafnium chloride (HfCl ₄ ), Cadmium chloride (CdCl ₃ ), Lanthanum chloride (LaCl ₃ ), Holomium chloride (HoCl ₃ ), Lithium bromide (LiBr) ), lanthanum nitrate _{(La (NO 3) 3)} , lithium iodide (LiI), lithium chloride (LiCl), magnesium perchlorate _{(Mg (ClO 4) 2)} , lutetium chloride (LuCl _3),
Nickel bromide (NiBr ₂ ), neodymium chloride (NdCl ₃ ), nickel nitrate (Ni (NO ₃ ) ₂ ), nickel iodide (Ni I ₂ ).
, Scandium chloride (ScCl ₃ ), praseodymium chloride (P
rCl ₃ ), strontium perchlorate (Sr (ClO ₄ ) ₂ ),
Samarium chloride (SmCl _3), terbium chloride (TbCl ₃₎
, Strontium iodide (Sr I ₂ ), yttrium chloride (Y Cl ₃ ), thulium chloride (TmCl ₃ ), zinc nitrate (Zn
(NO ₃ ) ₂ ), ytterbium chloride (YbCl ₃ ), barium acetate ((CH ₃ COO) ₂ Ba), zinc selenate (ZnSe O ₄ ),
Magnesium oxalate, cobalt oxalate, etc. are used.

Further, examples of the substance which reacts with water and absorbs heat include silver bromide (AgBr) and silver peroxybromide (AgBr 2 O 3).
₃ ), silver cyanide (AgCN), silver chloride (AgCl), silver peroxide chloride (AgCl O ₂ ), silver iodide (AgI), silver nitride (Ag N ₃ ).
, AgNCS, silver nitrite (AgNO ₂ ), silver nitrate (AgNO ₃ ), silver chromate (AgCrO ₄ ), silver sulfite (AgSO ₃ ), silver sulfate (Ag
SO ₄ ), barium nitrate (Ba (NO ₃ ) ₂ ), barium sulfate
(BaSO ₄ ), calcium fluoride (Ca F ₂ ), calcium hydrogen phosphate hydrate (CaHPO ₄・ 2H ₂ O), calcium sulfate hydrate (Ca SO ₄・ 2H ₂ O), [CoCl (NH ₃ ) ₅ ] Cl ₂ , [Co
(NH ₃ )] Br ₃ ), [Co NO ₂ (NH ₃ ) ₅ ] (No ₃ ) ₂ , phosphonic acid (H ₂ PHO ₃ ), orthoboric acid (H ₃ BO ₃ ), ammonium bromide (NH ₄ Br ), Ammonium chloride (NH ₄ Cl)
, Ammonium perchlorate (NH ₄ ClO ₄ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), ammonium hydrofluoride (NH ₄ H
F ₂ ), NH ₄ H ₂ As O ₄ , ammonium hydrogen phosphate ((N
H ₄ ) H ₂ PO ₄ ), ammonium iodide (NH ₄ I ₃ ), ammonium nitride (NH ₄ N ₃ ), ammonium nitrate (NH
₄ NO ₃ ), (NH ₄ ) SiF ₆ (cubic system), lead chloride (PbC
l ₂ ), radium chloride hydrate (RaCl ₂・ 2H ₂ O), radium nitrate (Ra (No ₃ ) ₂ ), radium sulfate (RaSO ₄ ), thallium bromide (TlBr), thallium chloride (TlCl), iodine Thallium oxide (TlI), TlNCS, thallium nitrate (TlNO ₃ ), [Ag
_{(NH 3) 2] ClO 4} , silver tungstate (AgWO _4), barium chlorate _{(Ba (ClO 3) 2)} , barium nitrite (Ba (NO _2)
2 ), cadmium cyanide (Cd (CN) ₂ ), [CoBr (NH ₃ )
₅ ] Br ₂ , [CoCl (NH ₃ ) ₅ ] Br ₂ , [Co (NH ₃ ) ₆ ] C
l ₃ , cesium perchlorate (Cs ClO ₄ ), cesium iodide
(CsI), cesium nitrate (CsNO ₃ ), copper perchlorate hydrate (Cu
_{(ClO 4) 2 · 6H 2} O), ammonium nitrate copper (Cu (NH _3)
4・ (NO ₃ ) ₂ ), Fe (CO) ₄ Br ₂ , H ₂ PtCl ₆・ 6H ₂ O
, Mercury nitrate hydrate (Hg (NO ₃ ) ₂・ 1 / 2H ₂ O, (Hg (NO ₃ )
₂ · 2H ₂ O), potassium perchlorate (KClO _4), potassium permanganate (KMnO _4), lithium perchlorate hydrate (LiC
lO ₄・ 3H ₂ O), ammonium iodate (NH ₄ IO ₃ ), ammonium chromate ((NH ₄ ) ₂ Cr ₂ O ₇ ), nickel cyanide (Ni (CN) ₂ ), rubidium chlorate (RbClO ₃ ),
Rubidium perchlorate (RbClO ₄ ), Rubidium nitrate (Rb
NO ₃ ), glycine, calcium oxalate hydrate, taurine, adenine and the like are used. These exothermic or endothermic substances may be used alone,
Moreover, you may make it mix and use 2 or more types in each group of an exothermic substance and an endothermic substance.

In the present invention, when the coating containing these exothermic or endothermic substances is provided, the temperature change caused by the exothermic or endothermic reaction of these substances with water changes depending on the amount, and if it is too small, Since the change in temperature is small and detection becomes difficult, it is desirable to take this point into consideration when coating.

[0014]

In the water intrusion detection line of the present invention, when water is infiltrated, a reaction between the exothermic or endothermic substance and water occurs at that portion, and the ambient temperature rises or falls. Therefore, if this phenomenon is detected by a distributed temperature sensor that utilizes the fact that it is a function of the intensity ratio temperature of Stokes light and anti-Stokes light due to Raman scattering,
Regardless of the high electric field, it is possible to accurately detect the position of flooded water over several kilometers.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a water immersion detection line according to an embodiment of the present invention.

In FIG. 1, the water immersion detection line of this embodiment has an optical fiber 1 such as a quartz fiber having a core diameter of 10 μm and a cladding diameter of 125 μm, and a primary coating 2 and a secondary coating made of an ultraviolet curable resin (UV resin). An exothermic substance such as calcium chloride that reacts with water to generate heat is further added to an optical fiber core wire 4 such as an SM type optical fiber core wire having an outer diameter of 250 μm, which is sequentially coated with the next coating 3. For example, the thickness of 3 to 20μ can be obtained by coating the UV resin or wrapping the resin molded into a tape shape.
The heat-generating coating 5 of m is provided.

In the water immersion detection line constructed as described above, when water is infiltrated, a reaction occurs between the water and the exothermic substance contained in the exothermic coating 5 at that portion to generate heat and the temperature rises. Therefore, if you connect a distributed temperature sensor to one end and check the temperature distribution of the optical fiber,
The temperature rising portion can be specified as the flooded position.

FIG. 2 is a perspective view showing a water immersion detection line of another embodiment of the present invention. In this embodiment, a plurality of single-core optical fiber core wires 4 as described above, for example, 2 to 4.
Four of them are arranged in parallel, and on the outer circumference of these four, in the same way as in the above embodiment,
For example, by coating with a UV resin added with an exothermic substance such as calcium chloride that reacts with water to generate heat, or by wrapping the resin molded into a tape
The structure is such that the exothermic coating 5 of 3 to 20 μm is provided.

Also in the water-immersion detection line constructed as described above, when water is infiltrated, a reaction between water and the heat-generating substance contained in the heat-generating coating 5 occurs at that portion to generate heat and the temperature rises. Connect a distributed temperature sensor to one end,
If the temperature distribution of the optical fiber is examined, the temperature rising portion can be accurately identified as the flooded position.

3 and 4 are perspective views showing further other embodiments of the present invention. In these embodiments, the outer circumference of the single optical fiber core wire 4 as described above is It has a structure in which a string-shaped or tape-shaped heating element 6 containing or coating a substance that generates heat by reacting with water such as calcium chloride is vertically (FIG. 3) or spirally wound (FIG. 4).

Also in the water intrusion detection line thus constructed, as in each of the above embodiments, if a distributed temperature sensor is connected to one end of the line and the temperature distribution of the optical fiber is examined, the temperature rises. The part can be accurately specified as the flooded position.

Although not shown, in the embodiment shown in FIG. 1, instead of the single-core optical fiber core wire 4, a plurality of such single-core optical fiber core wires 4 are arranged in parallel and the outer periphery thereof is arranged. And a multi-core optical fiber tape in which a primary coating and a secondary coating with a common UV resin are sequentially applied, or an optical fiber cable using such a multi-core optical fiber tape or a single-core optical fiber Similarly, in the case of using a multi-core optical fiber tape or an optical fiber cable instead of the single-core optical fiber core wire 4 in the embodiment shown in FIGS. 3 and 4, Similarly, by using the distributed temperature sensor, the flooded position can be accurately specified.

Further, in each of the above embodiments, the exothermic coating 5 and the exothermic body 6 are provided on the outer periphery of the optical fiber core wire or the optical fiber tape which has been generally used in the past. The present invention is not limited to such an embodiment, and a heating material (or an endothermic material) may be contained in a coating material that constitutes an ordinary optical fiber core wire or an optical fiber tape. That is, for example, in FIG.
In the embodiment shown in (1), the secondary coating 3, or the primary coating 2 and the secondary coating 3 may be coated with a material in which an exothermic substance (or an endothermic substance) is pre-blended.

The examples of the present invention will be described in more detail below.

Concrete Examples 1 to 8 A silica resin having a core diameter of 10 μm and a cladding diameter of 125 μm is coated with UV resin and cured to form a primary coating, and then a UV resin is further coated and cured to form a secondary coating. On the SM type optical fiber core wire with an outer diameter of 250 μm obtained by coating, a UV resin mixed with calcium chloride having various average particle diameters as shown in Table 1 was coated to a thickness of 5 μm to form a water detection line. It was made.

Next, a distributed type temperature sensor is attached to one end of the inundation detection line 400m, and from the attachment end.
We inundated 100m and investigated temperature change.
The waveform change was investigated using anti-Stokes light (0.81 μm).

The results are as shown in Table 1. In No. 7 in which the amount of calcium chloride added was small, the temperature change was small, and the location of the inundation was slightly difficult to identify. I was able to detect it. In addition, in No. 6 using calcium chloride having a large average particle diameter and No. 8 containing a large amount of calcium chloride, the appearance and mechanical properties were deteriorated.

[0029]

[Table 1] Specific examples 9 and 10 On the same SM type optical fiber core wire having an outer diameter of 250 μm as used in the above specific examples, mixed with calcium chloride having an average particle size of 3 to 5 μm on the surface of a nylon yarn of 1000 to 2500 denier. The water-immersion detection line was prepared by winding the coating applied (5-10 g / m 2 of calcium chloride) vertically or spirally.

Next, a distributed type temperature sensor is attached to one end of the inundation detection line 400m, and from the attachment end.
We inundated 100m and investigated temperature change.
The change in the waveform was investigated using anti-Stokes light (0.81 μm).

The results are as shown in Table 2, and in all cases, the flooded position could be easily detected.

[0032]

[Table 2]

[0033]

As is clear from the above embodiments, the flood detection line of the present invention can accurately detect the flood position over several kilometers regardless of the high electric field.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a perspective view showing still another embodiment of the present invention.

FIG. 4 is a perspective view showing still another embodiment of the present invention.

[Explanation of symbols]

 1 ... Optical fiber 4 ... Optical fiber core wire 5 ... Exothermic coating 6 ... Heating element

Claims (1)

[Claims] 1. A water immersion detection line comprising a heating element or a heat absorbing element containing a substance that reacts with water to generate heat or absorb heat, on the outer circumference of the optical fiber.