JPS6333445Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cable for detecting liquid leakage as a change in electrical characteristics.

With the development of the chemical industry in recent years, it has become possible for liquids such as oils such as crude oil, naphtha, gasoline, and kerosene, and acids such as sulfuric acid and hydrochloric acid to be transported in large quantities from one point to another via pipelines. This is done by making full use of control technology such as computer control.

If a leak occurs in such a pipeline or storage facility, it is not only a loss but also a danger, so it is desirable to detect the leak as early as possible, or to prevent the control system from functioning properly if water enters the controller, etc. Early detection is desired in order to ensure the safety of children, and various methods have been proposed for this purpose.

For example, a pulse signal is transmitted to a pair of parallel conductors arranged along a pipeline, etc.
The electrical properties between the conductors are changed by the leakage of liquid, and the pulse signal is reflected or absorbed based on the change in the electrical properties, and the location of the reflection or absorption of the pulse signal is determined. There is a method of detecting the location of liquid leakage by detecting. The conductor used in this case is a so-called liquid leakage detection cable.

For example, as this leakage detection cable,
The one described in Japanese Patent No. 44769 is known. This liquid leakage detection cable has a low permittivity braided dielectric between conductors that maintain a parallel relationship, and can detect leaks of highly viscous liquid. Since the distance between cables and the dielectric constant are not necessarily uniform along the longitudinal direction of the cable, there is a drawback that the electrical properties are non-uniform along the extending direction of the cable. This sometimes caused problems in matching the detection device and detecting the leakage point.

In view of this point, the object of this invention is to eliminate the above-mentioned conventional drawbacks and provide a leakage detection cable with uniform electrical characteristics.

Therefore, according to this invention, two parallel conductors,
A liquid leakage detection cable comprising dielectric tapes wound in a spiral manner with adjacent spacing to allow leakage liquid to flow between the parallel conductors, and a liquid-permeable jacket surrounding the outer periphery of the dielectric tapes. form. When formed in this way, the distance between the parallel conductors is kept uniform along the extending direction of the cable, making it possible to provide a liquid leakage detection cable with uniform electrical characteristics, and as a result, it is possible to detect liquid leakage points. The effect of increasing precision can be obtained.

Next, this invention will be explained in more detail with reference to the drawings.

In FIG. 1, a dielectric tape 3 is provided around the outer periphery of a central conductor 1 forming one parallel conductor, which is wound in a spiral shape with an interval 2 between adjacent conductors.
A liquid-permeable outer conductor 4 forming the other parallel conductor surrounds its outer periphery. A liquid-permeable jacket 5 made of, for example, a braided insulator is further provided around the outer periphery of the external conductor 4 to protect the internal members. As the liquid-permeable external conductor 4, for example, a braided conductor, a horizontally wound conductor, or a conductive tape wound in a spiral shape with adjacent intervals maintained can be effectively used.

According to the liquid leakage detection cable according to the present invention having such a configuration, the dielectric tape 3 provided between the two conductors 1 and 4 has a uniform thickness, so that the spacing between the conductors is uniform over the entire length of the cable, so that electrical The characteristics are also uniform, and an extremely stable leakage detection cable can be obtained. Incidentally, since the dielectric tape 3 is wound so as to maintain the distance 2 between adjacent conductors, there is no problem with liquid leaking into the space between the conductors 1 and 4. Furthermore, if fluororesin is used as the material of the dielectric tape 3, it is possible to obtain a stable liquid leakage detection cable with a long life since it is electrically, chemically and physically superior. In addition, since fluororesin is highly water-repellent, it will not operate unless a certain level of water head pressure is applied, which is extremely convenient when detecting liquid, especially water, since it eliminates malfunctions due to simple splashing of water.

FIGS. 2 and 3 show other embodiments based on this invention, and the same effects as the embodiment shown in FIG. 1 can be obtained.

The embodiment shown in FIG. 2 shows an example in which a dielectric tape 8 and a perforated tape 9 are wound spirally between the center conductor 1 and the liquid-permeable outer conductor 4 with a space between them. Similarly, the embodiment shown in FIG. 3 includes a perforated tape 10 and a dielectric tape 11 wound spirally.
We will show an example using , and the same effect can be obtained in either case.

FIGS. 4 and 5 show still another embodiment of this invention, in which a pair of opposing conductors are used as parallel conductors.

In FIG. 4, a dielectric tape 14 is provided between the opposing conductors 12 and 13, and is wound in a spiral manner with an interval between adjacent conductors.
are made of a relatively hard material, and both opposing conductors 12,
It also acts as a distance keeper between the 13 spaces.
A liquid-permeable jacket 15 is provided on the outer periphery of these. Note that the dielectric tape 14 can be made of a material selected from among fibers, perforated tape, porous material, and the like.

FIG. 5 shows a dielectric tape 19 according to the present invention spirally wound around the outer peripheries of opposing conductors 17 and 18 with a distance between them determined by a spacing piece 16, and passed through the outermost periphery. An example in which a liquid jacket 20 is applied is shown. In this case as well, a member selected from among fibers, perforated tape, porous material, etc. may be applied together with the dielectric tape 19.

In the first to fifth embodiments described above, the center conductor 1,
Outer conductor 4 and counter conductors 12, 13, 17, 1
8 is made of any one of electrical annealed copper wire, tin-plated annealed copper wire, and silver-plated annealed copper wire; dielectric tapes 3, 8, 11; perforated tapes 9, 10;
15, 20 and the spacing piece 16 are made of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP) among fluororesins, and porous PTFE obtained by stretching PTFE. This has been particularly suitably selected.

As described above, according to this invention, since the distance between the parallel conductors can be formed uniformly over the entire length of the cable, it is possible to obtain a leakage detection cable with uniform electrical characteristics, which also improves the accuracy of detecting leakage points. It has great practical value because it can be enhanced.

[Brief explanation of the drawing]

Figures 1 to 3 are explanatory diagrams of coaxial leakage detection cables showing different embodiments of this invention, and Figures 4 and 5 are opposing conductor type leakage detection cables showing further different embodiments of this invention. FIG. 1... Center conductor, 3, 8, 11... Dielectric tape, 4... Outer conductor, 5... Outer cover, 9, 10...
Perforated tape, 12, 13, 17, 18... opposed conductor, 15, 20... outer covering, 16... spacing piece.

Claims (1)

[Claims for Utility Model Registration] (1) Two parallel conductors, a dielectric tape wrapped in a spiral shape with a space between adjacent conductors to allow liquid leakage to flow between the parallel conductors, and their outer periphery. A liquid leakage detection cable equipped with a liquid-permeable outer sheath that surrounds the liquid leakage detection cable. (2) Utility Model Registration In the liquid leakage detection cable according to claim 1, the parallel conductor consists of a center conductor and a liquid-permeable outer conductor disposed surrounding the outer periphery of the center conductor, and A leakage detection cable characterized by a dielectric tape wrapped in a spiral around the outer periphery of a center conductor. (3) In the liquid leakage detection cable according to claim 1 of the utility model registration claim, the parallel conductors are composed of opposing conductors, and a dielectric tape is disposed between the opposing conductors. cable. (4) In the liquid leakage detection cable described in claim 1 of the utility model registration, the parallel conductors consist of opposing conductors arranged at equal intervals with spaced pieces in between, and a dielectric tape is adjacent to the outer periphery of the opposing conductors. A liquid leakage detection cable characterized by being arranged at intervals. (5) In the liquid leakage detection cable according to claims 1 to 4 of the utility model registration claim, the dielectric tape is arranged together with a member selected from fibers, perforated tape, and porous material. A liquid leakage detection cable characterized by: (6) In the liquid leakage detection cable according to any one of claims 1 to 5 of the claims for utility model registration,
A liquid leak detection cable characterized in that the dielectric tape is made of fluororesin.