JPS61285614A - Heat resistant wire/cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to the improvement of electric wires and cables having an insulating layer formed into a porous structure by foaming, etc., and particularly improves electrical properties, flexibility, etc. (Regarding heat-resistant wires and cables with improved heat resistance.)

[Conventional technology]

Traditionally, in communication cables such as coaxial cables, insulators formed into porous structures by foaming, stretching, etc. have been used due to requirements for electrical properties. The porosity (the volume of voids in a porous body expressed as a percentage) of a porous insulator has a very wide range of about 10 to 90%. Increasing the porosity of the insulator lowers the dielectric constant and dielectric loss tangent, which is advantageous for improving electrical properties.Also, in highly porous cables, it is important to increase the conductor diameter even if the cable size is the same. Highly porous cables are being developed because they have the advantage that they can be made larger to reduce the amount of resistance attenuation, thereby reducing the cable diameter and material cost.

Incidentally, in recent years, electric wires and cables used in high-temperature environments, such as sensor lead wires and control cables around nuclear reactors and other high-temperature reactors, are also being insulated with porous structures as described above due to electrical characteristics requirements. The application of electric wires and cables with a body is being considered. In this case, as a means of imparting heat resistance to the above-mentioned electric wires and cables, for example,
Publication No. 9-42711, Japanese Patent Publication No. 59-9660
As proposed in Publication No. 6, a heat insulating layer mainly made of inorganic materials such as mica, glass fiber, and asbestos, which have been conventionally used in general heat-resistant wires and cables, is provided on the outside of the insulator or sheath. The idea is that the heat insulating layer prevents the internal porous insulating layer and sheath layer from burning and maintains the functionality of the wires and cables.

[Problem that the invention seeks to solve]

However, in the above conventional example, especially when an insulating layer with high porosity is used, it is easily affected by temperature, and unless the insulation layer provided on the outside has high insulation performance, continuous use at high temperatures or Due to repeated overheating, etc., the porous structure of the insulating layer collapses due to shrinkage, rupture, etc., and the porosity decreases, making it no longer possible to maintain its original function as an insulator, resulting in significant changes in electrical properties such as characteristic impedance. So there is a problem.

Therefore, it is essential that the thickness of the heat insulating layer be very large. However, since the insulation layer is mainly made of inorganic materials, if the insulation layer is formed thickly to increase the insulation effect, the resulting electric wires and cables will have extremely poor flexibility, and there are restrictions depending on the place of use. may be received. Furthermore, when used for a long time in a high temperature atmosphere, it is difficult to completely insulate the porous insulating layer from heat even if the coating thickness of the heat insulating layer is increased, and there is a limit to continuous use. In addition, due to the lack of flexibility as mentioned above, the heat insulation layer may crack or peel off during long-term use due to vibrations during handling or use, resulting in poor heat resistance properties, etc. However, it was still not sufficient.

The present invention solves the problems of the prior art described above, and improves the electrical properties of electric wires and cables having porous insulating layers.
The purpose is to provide heat-resistant wires and cables that have improved heat resistance without impairing flexibility.

[Means for solving problems]

The present invention has been made to solve the problems of the prior art described above, and therefore, according to the present invention, at least one insulated wire core having a porous insulating layer on the outer periphery of the conductor, and the insulated wire A heat-resistant electric wire/cable is constructed, comprising a tube that accommodates the insulated wire core, and a spacer that supports the insulated wire core while leaving a longitudinally continuous fluid passage inside the tube.

In this configuration, the insulated wire core housed in the tube made of a flexible metal tube or the like may be not only a normal porous insulated wire but also a shielded wire having a shield layer around the outer periphery of the porous insulating layer. Alternatively, a plurality of insulated wire cores may be bundled to form a multi-core cable. In addition, these electric wires and cables can be stored in a flexible conduit made of stainless steel flexible pipe, for example, instead of being stored directly in a pipe, and if necessary, a double structure or more It is also possible to use it as

[Effect]

According to this invention, as described above, at least
□One porous insulated wire core is supported by a spacer and housed in a pipe leaving a continuous fluid passage in the longitudinal direction.□
Because of its structure, when used in high-temperature atmospheres, by circulating gas or liquid through the fluid passages,
It becomes possible to prevent a rise in temperature of the porous insulating layer housed inside. Therefore, the porous nature of the insulating layer can be improved even without providing a heat insulating layer mainly made of inorganic materials on the outer periphery of the porous insulating layer as in the past.

The structure remains stable and changes in electrical properties occur.
:・Since there is no heat resistant wire/cable, it is extremely reliable.

Furthermore, not only is there no need for a heat insulating layer, but if the porous insulated wire core is housed in a flexible metal tube, there is only a slight decrease in flexibility due to the heat-resistant structure.
Bending wiring in narrow spaces is also possible.

〔Example〕

FIG. 1 is a partially sectional front view showing an embodiment of the heat-resistant wire/cable according to the present invention, and FIG. 2 is a side view of the heat-resistant wire/cable of the embodiment shown in FIG.

This heat-resistant wire/cable 1 shows a case where it is applied to a coaxial cable, and a porous insulating layer 3 obtained by various methods such as foaming method and stretching method is provided around the outer periphery of an inner conductor 2 provided in the center. Further, an insulated wire core 6, which has a shield layer (outer conductor) 4 and a protective coating 5 sequentially provided on its outer periphery, is inserted into a flexible conduit tube 7 and connected via a connector at its terminal end. A flexible electrical conduit tube 7 is supported by a ring-shaped body 8 serving as a spacer provided at at least two locations in the longitudinal direction, and a flexible metal tube 10 is formed so as to leave a continuous fluid passage 9 around the circumference in the longitudinal direction. It is stored in. In this embodiment, as shown in FIG. 2, a flexible electrical conduit 7 into which an insulated wire core 6 is inserted has both end portions 8 bent inside a ring-shaped body 8 serving as a spacer.
It has a configuration in which it is supported so as to be held at the center of the ring-shaped body 8 by being sandwiched between the rings 8a and 8b. In addition,
Union couplings 1 are provided at both ends of the flexible metal tube 10.
1 is attached.

Next, the manner of use of this heat-resistant electric wire/cable 1 will be explained based on FIG. 3. In Figure 3, this heat-resistant wire/cable l has union couplings 1 at both ends.
The insulated wire core 6, which is connected to the junction box 20, 21 by 1 and roughly integrated with the flexible conduit 7, is connected to a control unit (not shown) via a connector attached to the terminal part, respectively.
Connected to the sensor section, etc. And high temperature atmosphere 23
When used inside, air 24 is continuously fed into the fluid passage 9 within the flexible metal tube 10 from one junction box 20 provided outside the high temperature atmosphere 23.

The air 25 heated while passing through the flexible metal tube IO is sucked into or discharged into the other junction box 21, and is further discharged from the exhaust port 22 provided in the junction box 21.
6 and is discharged. Therefore, since the insulated wire core 6 in the flexible metal tube 10 is always surrounded by fresh air, the temperature of the insulated wire core 6 increases only slightly even in the high-temperature atmosphere 23, and the temperature rises above a predetermined temperature. It no longer rises and can be used continuously for a long time.

In this embodiment, the insulated wire core 6 is housed in a flexible conduit tube 7 and then housed in a tube made of a flexible metal tube 10.
In the case of such a double structure, the insulated wire core 6 is not directly exposed in the fluid passage 9, so that by using a liquid as the cooling fluid, it is possible to use it in a particularly high temperature atmosphere.

In the above embodiment, the cooling fluid is sent from one junction box 20 toward the other junction box 2I, and is discharged from the other junction box 21, but the heated fluid is heated to a high temperature. If the fluid cannot be discharged to the atmosphere side, one more flexible metal tube may be used to form a concentric three-layer structure to form two fluid passages. In that case, the inner fluid passage and the outer fluid passage are connected at the end on the other junction box 21 side, and cooling fluid is passed through the inner fluid passage at the end on the other junction box 21 side. The fluid can be turned around and returned to one of the junction boxes 20 through the outer fluid passageway.

In any case, if the insulated wire core 6 is housed in a flexible tube made of a flexible metal tube, the inherent flexibility of the insulated wire core 6 will not be significantly reduced. Therefore, it has superior flexibility compared to conventional products with a heat insulating layer, so it can be used in narrow spaces without any problems.

〔Effect of the invention〕

As explained above, according to the present invention, at least one
Since the porous insulated wire core is supported by a spacer and housed in a tube such as a flexible metal tube, leaving a continuous fluid passage in the longitudinal direction, it is suitable for use in high-temperature atmospheres. Furthermore, by passing cooling gas or liquid through the fluid passage, it is possible to prevent the temperature of the porous insulated wire core housed inside from increasing. Therefore, even with conventional products, even if a thick insulating layer made of inorganic materials is provided, the temperature cannot be avoided when used continuously for a long time, and the insulating layer is affected by this, resulting in changes in electrical characteristics. In contrast, in the heat-resistant wires and cables of the present invention, the temperature of the insulated wire core can be kept constant by flowing a cooling fluid, without the need to specifically provide a heat insulating layer mainly made of inorganic materials as in the past. As a result, the porous structure of the porous insulating layer is not destroyed, but also shrinks and expands to a very small extent, so that the porous structure is stably maintained. Therefore, there is no change in electrical characteristics, and the device is extremely reliable for long-term continuous use in a high-temperature atmosphere.

Furthermore, there is no particular need for a heat insulating layer mainly made of inorganic materials,
In addition, since the porous insulated wire core can be housed in a flexible metal tube, there is only a slight reduction in the inherent flexibility of the insulated wire core, which is not seen in conventional products. The heat-resistant wire/cable is flexible and has good electrical characteristics, and is particularly suitable for use in narrow spaces.

In addition, in the present invention, the porous insulation layer of the insulated wire core may have either continuous pores or independent pores, but in particular, it is difficult to create a heat-resistant structure with a conventional method due to its weak mechanical strength. Effective for protecting insulated wire cores that have an insulating layer.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, a plurality of insulated wire cores housed in a tube such as a flexible metal tube or a heat-resistant flexible synthetic resin tube may be bundled to form a multi-core cable. In addition, as the cooling fluid, a liquid such as water may be used in addition to gas.

Furthermore, it is of course possible to make various changes within the technical idea of the present invention, such as changes in the shape, quantity, material, etc. of the spacers.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view of a heat-resistant wire/cable according to the present invention, FIG. 2 is a side view of the heat-resistant wire/cable of the embodiment shown in FIG. 1, and FIG. 3 is a heat-resistant wire/cable of the embodiment shown in FIG. FIG. 3: porous insulating layer, 6: insulated wire core, 8 varnish spacer, 9 fluid passage, 10: flexible metal tube. Patent applicant: Jun Ko Co., Ltd. Company 3: Porous serpentine layer 2, ζ ζ book & core ε spacer 4゛Flow iFudryiO2 Visible metal 1

Claims (4)

[Claims] (1) At least one insulated wire core having a porous insulating layer on the outer periphery of the conductor, a tube that houses the insulated wire core, and a fluid passage that continues in the longitudinal direction of the insulated wire core within the tube. Heat-resistant wires and cables equipped with a spacer for support. (2) The heat-resistant electric wire/cable according to claim 1, wherein the insulated wire core has a shield layer around the outer periphery of the porous insulating layer. (3) In the heat-resistant electric wire/cable according to claim 1 or 2, the insulated wire core is housed in a flexible conduit tube, and the flexible conduit tube is connected to a flexible metal tube via a spacer. A heat-resistant wire/cable that is housed in a tube made of (4) In the heat-resistant electric wire/cable according to claim 3, the spacer is a metal ring-shaped body with both end portions bent inward, and the flexible conduit A heat-resistant electric wire/cable characterized by being latched to and supported at the center of a ring-shaped body.