JPH0770254B2 - Flat pressure-sensitive cable - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pressure-sensitive cable, and more particularly to a pressure-sensitive cable capable of detecting a pressure-sensitive position in a lengthwise direction of a wire.

[Technical background]

To date, many pressure sensitive cables or switches have been proposed. However, these are related to a pressure-sensitive cable (pressure-sensitive switch) for detecting a passing vehicle on the road or opening and closing a door of a doorway of a house or a store (see Japanese Utility Model Laid-Open No. 62-31830). ).

In contrast, in recent years nuclear power plants and liquefied natural gas (LNG)
Measures are being demanded to prevent intruders from entering bases and the like. When a pressure-sensitive cable is adopted as such an intruder prevention measure, it is necessary to know at which position on the outer wall of the facility (facility) the intruder existed, but unfortunately the pressure-sensitive cables proposed so far have been used. Cables did not meet these intended purposes.

Further, when the pressure-sensitive cable is laid, the flat cable is less likely to be twisted and laid like a round cable.

[Problems to be Solved by the Invention]

In view of the above situation, in the present invention, a nuclear power plant or
A flat pressure-sensitive cable that can be laid around the outer wall of an LNG terminal (surrounded) so that if there is an intruder from this outer wall, the pressure applied by the intruder can be detected and the location of the intrusion can be immediately notified to the security center. The challenge is to provide.

[Means for Solving the Problems of the Invention]

In order to solve the above problems, in the present invention, an elastic conductive layer is provided on an electric conductor to form an internal pressure-sensitive electrode, and at least two internal pressure-sensitive electrodes having the same diameter as the elastic conductive layer are provided. Insulating conductors are arranged in parallel, and an elastic conductive layer, an air insulating layer, an external pressure-sensitive electrode, and a protective jacket are sequentially provided thereon.

The external pressure-sensitive electrode may be composed of an elastic conductive layer and a braided conductor layer, and instead of the braided conductor layer, it may be a vertically attached layer such as a metal foil strip or a wound layer.

The air insulating layer can be formed by braiding and wrapping an electrically insulating yarn, and the electrically insulating yarn can be a solid plastic yarn or the like, and is preferably a strong twist yarn.

The air insulating layer may have a braid density of 35 to 80. If it is less than 35, malfunction tends to occur, while if it exceeds 80, it becomes less sensitive to pressure.

[Action]

In the present invention configured as described above, since it is flat, there is little fear that it will be twisted and laid, and because the internal pressure-sensitive electrode and both insulated conductors have the same diameter and are parallel, The layer thickness of the elastic conductive layers above and below the electrodes may be the same, and a uniform deformation of the elastic conductive layer is performed against pressure.

When this flat pressure-sensitive cable is laid at a required position and is pressurized, the elastic conductive layer is eroded in the air insulating layer, and the inner and outer pressure-sensitive electrodes are electrically connected. In the case where the elastic conductive layers are provided on both sides of the air insulating layer, the elastic conductive layers are eroded from both sides, so that the conduction action becomes more reliable.

Therefore, for example, the pressure-sensitive cable according to the present invention is laid at a detected position, and a relay is provided between one insulated conductor and the internal pressure-sensitive electrode or the external pressure-sensitive electrode at an appropriate interval in the laying direction. In addition, an a contact of the relay is provided between the two insulated conductors, and a constant voltage is applied between the one insulated conductor and the external pressure sensing electrode or the internal pressure sensing electrode. In this state, when an intruder or the like pressurizes the pressure-sensitive cable according to the present invention at a certain laying position, the internal pressure-sensitive electrode and the external pressure-sensitive electrode are brought into conduction as described above, and the relay operates. Then, both insulated conductors are short-circuited. This short-circuit signal sounds an alarm or the like. Obtain the resistance value of both insulated conductors up to the short-circuit point, and confirm the position based on the resistance value.

〔Example〕

As shown in Table 1 and FIG. 1, first, an elastic conductive layer 1b is provided on an electric conductor 1a made of a tin-plated annealed copper stranded wire to form an internal pressure-sensitive electrode 1, and a conductor 2a made of an annealed copper concentric stranded wire is formed. By providing a vinyl chloride insulator 2b on the inner side of the two inner pressure-sensitive electrodes 1 to be signal lines, an insulated conductor 2 having the same diameter is formed. Coat with layer 3.

At this time, the elastic conductive layer 1b of the internal pressure-sensitive electrode 1 also serves as the elastic conductive layer 3, that is, without providing the elastic conductive layer 1b,
It is conceivable that the elastic conductive layer 1b may be integrally extruded when the elastic conductive layer 3 is extruded. However, in doing so, the thickness of the elastic conductive layers 3 above and below the outer periphery of the electric conductor 1a becomes large, and a sinking state occurs due to "sinking",
There is a possibility that electrical continuity will not be achieved due to smooth eating out, which will be described later. Further, the elastic conductive layer 3 is also thermally crosslinked, but if the layer thicknesses are greatly different, there is a possibility that uniform crosslinking may not be achieved over the entire region. Therefore, after forming the elastic conductive layer 1b to form the internal pressure sensitive electrode 1, the elastic conductive layer 3 is formed.

Next, a strongly twisted Tetoron yarn having a twisting ratio of 1.23 is braided on the outer periphery thereof to form an air insulating layer 4, and an outer elastic conductive layer 5, a tinned annealed copper wire braided conductor 6 and a vinyl chloride sheath 7 are further formed thereon. Were sequentially provided to obtain the pressure-sensitive cable P according to the present invention. In this embodiment, the external elastic conductive layer 5 and the tin-plated annealed copper wire braided conductor 6 constitute an external pressure-sensitive electrode.

In this embodiment, when the outer elastic conductive layer 5 is pressure-heated and cross-linked, the conductive rubber bites into the gap of the Tetron braid 4 and the desired pressure-sensitive cable P cannot be obtained.
Therefore, the extrusion molding was carried out by using a pipe extrusion die nipple and then hot-wire crosslinking. When it is unavoidable that pressure crosslinking is unavoidable, it is necessary to seal an inert gas inside to prevent the above bite.

The conductor 2a of the insulated conductor 2 is concentrically twisted (7 / 0.40) for the following reason. That is, when the cable P is flat, if the cable P is repeatedly bent in the major axis direction, in the case of collective twisting, the individual strands will be slackened and kinked, resulting in malfunction. On the other hand, it was confirmed that the concentric twist did not cause the problem, and it was adopted.

Here, the elastic conductive layers 1b, 3 and 5 have a volume resistivity 4.
A range of 0 to 7.0 Ωcm, impact resilience of 50 to 60 (%), and rubber hardness of 60 to 75 degrees is sufficient. In the example, a silicone conductive rubber manufactured by Toray Silicon Co., trade name SE6765U is kneaded with an appropriate amount of a crosslinking agent. The resulting product had a volume resistivity: 4.0 Ωcm, impact resilience: 54%, and rubber hardness: 50 degrees.

In addition, Tetoron braid 4 is a strongly twisted yarn with a twist rate of 1.23, diameter: 0.7
Braided in mm, and at any of the densities F: 60%, 54%, and 50%, the elastic conductive layers 3 and 5 penetrated into the gap between the braids 4 by pressurization, and good conduction was obtained. On the other hand, a braided yarn with a twist ratio of 1.15 and a diameter of 1.0 mm were also braided in the same manner, but the apparent outer diameter was large, causing fatigue, and the operation became unstable, such as a short circuit with a small pressure.

The braid density F was calculated by the following formula.

θ: Braid angle D: Braid average diameter (braid bottom diameter + 2d) d: Braid wire diameter or braid tape thickness L: Braid pitch p: Number of crosses per unit length m: Number of strokes W: nd or width of braided tape n: Number of possessions Next, the intruder detection system using the above embodiment will be described.

First, as shown in FIG. 2, a pressure-sensitive cable P according to the embodiment is laid along a simulated outer wall, and terminals are arranged at required intervals (sections) S ₂ S ₃ ... S _n-1 in the laying direction. The boxes A ₁ , A ₂ ... A _n are provided. Next, except for A _{1 of the} terminal box, the other ones include relays R ₂ , R ₃ ... R _n between one insulated conductor 2 (conductor 2a) and the internal pressure-sensitive electrode 1 (conductor 1a). , And the relay's a contacts R _a2 , R _a3 ... R _an between the insulated conductors 2 and 2.
And ground the braided conductor 6 (external pressure sensitive electrode). In the figure, R _c2 ... R _cn are coils for holding a contact of each relay R.

In this circuit, one of the insulated conductors 2 to a DC voltage: in a state of applying 24V, the required distance S ₂ ... either S _n-1, for example, if there is an intruder in the zone S _3, the laying pressure sensitive When the cable P is stepped on, both elastic conductive layers 3 and 5 dig into the insulating braid 4 by the pressurization, and both are conducted, and one of the insulated conductors 2 is grounded via the internal pressure-sensitive electrode 1 and the relay R ₃
Is activated, its a-contact R _a3 is closed like a chain line, both insulated conductors 2 and 2 are short-circuited, and the state is maintained by the coil R _c3 .

This short circuit signal is input to the controller C of the management center (security center), and an alarm or the like sounds. On the other hand, in response to the short-circuit signal, the controller C measures the resistance of the insulated conductor 2 up to the short-circuited place by the conductor resistance measuring device D, and the measured value and the preset terminal boxes A ₁ ... A _n. The terminal box A ₃ is confirmed by comparing the reference resistance values of, and the output T ₃ indicates that there is an intruder in the section S ₃ . The section display lamp is turned on by this output T ₃ . Since the ends of the insulated conductors 2 and 2 are stepped down and short-circuited, if the wire is disconnected, the resistance value becomes infinite and the wire output T ₀ is performed.

In this embodiment, each terminal box A ₂ ... A _n is provided with an oscillator operated by each relay R ₂ ... R _n , and the transmission frequency of the oscillator is changed to transmit to the controller C. It is possible to identify the frequency and display the intrusion section. Furthermore, the transmitter is used as a voice synthesis transmitter, and the intrusion section is displayed by the voice at the management center. For example, "S ₃ section intruder It can be broadcast like "Yes" and threatened by intruders.

Also, one of the insulated conductors 2 and the external pressure-sensitive electrode (braided conductor 6)
Relays R ₂ ... R _n may be provided between them to ground the internal pressure-sensitive electrode 1.

Further, in the controller C, by the conductor resistance measuring device D,
A resistance value can be measured between the pressure-sensitive cable P and one of the insulated conductors 2, and the resistance between the pressure-sensitive cable P and the insulated conductor 2 up to a short-circuited place is measured, and the measured value and a preset value are set. By comparing the pressure-sensitive cable P and the reference resistance value up to the required length between the insulated conductors 2 and calculating the length of the pressure-sensitive cable P corresponding to the reference resistance value, the point corresponding to the length is calculated. Can be a short circuit point. That is, not only the sections S ₂ ... S _n-1 but also the short circuit point can be detected.
Impedance and capacitance may be used instead of the resistance value.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The present invention is configured as described above and is a flat pressure-sensitive cable in which insulated conductors are arranged in parallel. Therefore, the present invention is very effective as an intruder detection cable for a nuclear power plant or the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the pressure-sensitive cable according to the present invention, and FIG. 2 is a usage explanatory diagram of the same embodiment. 1a ... electric conductor, 1b ... elastic conductive layer, 1 ... internal pressure-sensitive electrode, 2a ... electrical conductor, 2b ... vinyl chloride insulator, 2 ... insulated conductor, 3 ... internal elastic conductive layer, 4 …… Insulation braid (air insulation layer), 5 …… External elastic conductive layer, 6 …… Tin-plated annealed copper wire braided conductor, 7 …… Protective jacket (sheath), A ₁ , A ₂ …… A _n …… Terminal box , R ₂ … R _n …… Relay, R _{a2 ・ ・ ・} R _an …… Relay a contact, S ₂ …… S _n …… Required interval (section), C …… Controller, D …… Conductor resistance measuring instrument, P …… Pressure sensitive cable.

Front page continued (72) Inventor Seiji Hino 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Cable Co., Ltd. (72) Inventor Hiroyuki Oura 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Cable Co., Ltd. (56) References: Actually open Sho 62-31830 (JP, U)

Claims (6)

[Claims] 1. An elastic conductive layer 1b is provided on an electric conductor 1a to form an internal pressure-sensitive electrode 1, and at least two insulated conductors 2a having the same diameter as the elastic conductive layer 1b are arranged in parallel with the internal pressure-sensitive electrode 1. A flat pressure-sensitive cable characterized in that an elastic conductive layer 3, an air insulating layer 4, an external pressure-sensitive electrode 5, and a protective jacket 7 are sequentially provided on the elastic conductive layer 3. 2. The flat pressure-sensitive cable according to claim 1, wherein the external pressure-sensitive electrode 5 comprises an elastic conductive layer and a braided conductor layer. 3. The flat pressure-sensitive cable according to claim 1, wherein the air insulating layer 4 is formed by braiding or winding an electrically insulating thread. 4. The flat type pressure-sensitive cable according to claim 3, wherein the electrically insulating thread is a solid plastic thread. 5. The flat pressure-sensitive cable according to claim 3, wherein the electrically insulating yarn is a strong twist yarn. 6. The flat pressure-sensitive cable according to any one of claims 3 to 5, wherein the air insulation layer 4 has a braid density of 35 to 80.