JPH01200516A - Fire-resistant spiral leakage coaxial cable - Google Patents

Abstract

PURPOSE:To enable the use of fire and police service radiowave in a radiowave blind zone by using a bridging polyethylene as an inner insulator and non- halogen fire-resistant polyethylene as an outer cover respectively for increasing fire resistant quality, and forming 8 spiral leakage coaxial cable free from the generation of toxic gases. CONSTITUTION:A bridging polyethylene is used as an inner insulator 3 and a non-halogen fire resistant polyethylene is used as an outer cover 6, thereby enabling the formation of a spiral leakage coaxial cable having substantially high fire-resistant quality and freedom from toxic gas generation, compared with a conventional cable having a polyethylene insulator and an outer cover. The use of subject cable makes it possible to receive a radiowave in a blind zone such as an underground street and tunnel. Because of the fire-resistant quality, the cable can be used for fire and police radiowave services while ratio broadcasting is interrupted in an emergency such as a fire. Furthermore, the use of a non-halogen fire-resistant polyethylene eliminates an occurrence of toxic gases and the degree of a danger is thereby reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cable for radio reception in radio wave blind areas such as underground malls and tunnels, and for wireless communication with the ground.
The present invention relates to a leaky coaxial cable used in wireless communication auxiliary equipment, which is particularly effective for disaster prevention and wireless communication during disasters.

[Problems to be Solved by the Prior Art and Inventions It is difficult to secure communication with moving objects such as automobile radios or with the ground in radio wave dead zones such as inside codonnels, underground malls, and reinforced concrete buildings. As a means to solve this problem, antenna systems and open transmission lines have been researched, but spiral leaky coaxial cables, which leak radio waves from the external conductor and skillfully integrate transmitting/receiving antennas and transmission lines, have excellent characteristics. It is a very effective means. For this reason, it is used in tunnels and underground malls, etc.
The Fire Service Law Enforcement Regulations have been promulgated as a means of disaster prevention management for these locations, and regulations regarding underground malls, including underground passages, have been further strengthened. Therefore, automatic fire alarm equipment, emergency warning gears, guide lights, etc. must be installed, and the wiring used for these must be made of fire-resistant and heat-resistant wires. Furthermore, in underground shopping malls with a total area of more than 1,000 square meters, wireless communication between the fire radio connected to the ground terminal of the disaster prevention center or the firefighter taking command on the ground, and the portable radio of the firefighter underground, It is stipulated that auxiliary wireless communication equipment using leaky coaxial cables be installed in underground malls. Leaky coaxial cables are also installed inside the tunnels to ensure that fire and police radios using VHF and UHF band mobile radios are not sensitive to radio waves inside the tunnels.

The structure of the spiral leaky coaxial cable used in such a wide range is as shown in the figure. In the figure, the leaky coaxial cable has an inner conductor 2 wound in a spiral shape around a magnetic core 1, the inner conductor 2 is covered with an inner insulator 3, and an outer conductor 4 is spirally wound around the inner insulator 3. rolled,
The outer conductor 4 is formed by being covered with a jacket 6 together with the support wire 5 .

The inner insulator 3 and the outer jacket 6 are made of polyethylene. Polyethylene has a low dielectric constant and dielectric loss tangent, and is almost independent of temperature and frequency, and its insulation resistance and dielectric strength are stable, making it an excellent cable insulator. It is also mechanically strong and chemical resistant.
In addition to solvent resistance, it has excellent water and moisture resistance, and is widely used as a cable insulator.
The drawback was that it had poor heat resistance and was easily combustible. the current,
Although the heat resistance and flame retardance of helical leaky coaxial cables are not regulated, it is quite conceivable that heat resistance and flame retardance will be required in the future for disaster prevention purposes.

[Means for Solving the Problems] In order to solve the above-mentioned problems, it is an object of the present invention to form a helical leaky coaxial cable by forming an internal insulator from cross-linked polyethylene and an outer sheath from flame-retardant polyethylene that does not contain halogen. There is a particular thing.

The crosslinked polyethylene forming the internal MID body has improved heat resistance and is less likely to melt than polyethylene. The allowable temperature for polyethylene is 75° to 80° C. continuously and 140° to 150° C. for a short circuit, whereas the allowable temperature for crosslinked polyethylene is as high as 90° C. continuously and 230° C. for a short circuit. It is extremely useful because it can improve heat resistance without impairing the electrical properties of polyethylene.

Cross-linked polyethylene is made by irradiating polyethylene with an electron beam.
There are two methods: creating a network molecular structure, and crosslinking polyethylene by applying an organic peroxide such as dialkyl peroxide or acyl peroxide.

The material used for the cable jacket must be flame retardant for emergencies and disaster prevention. In addition, especially in underground malls and tunnels, in the event of a major fire, it is best to use a flame retardant that does not emit toxic gases that would have a negative impact on the human body or electronic equipment, so it is better to refrain from using halogen-containing flame retardants as much as possible. , tricresyl phosphate as li-burning polyethylene,
Phosphate esters such as crecylphenyl phosphate and octyldiphenyl phosphate, phosphorus-containing polyols, and inorganic substances such as antimony trioxide, sodium antimonate, tin oxide, barium metaborate, zirconium oxide, and red phosphorus are added to polyethylene as additives. It is added. The blending ratio of the flame-retardant polyethylene is preferably about 50% by weight of polyethylene and about 50% by weight of non-halogen flame-retardant polyethylene.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

In the figure, on the outside of the magnetic core 1 with an outer diameter of about 6.5 ma+,
An internal conductor 2 is formed by horizontally winding a 0.2I annealed copper wire, and an insulator 3 is formed by coating the outer periphery with cross-linked polyethylene to an outer diameter of about 12 mm. 0.2 on the outside of insulator 3
mm annealed copper wire horizontally wound to form the outer conductor 4, 1.4+m
The supporting wire 5 is made of 7 galvanized copper strands with a cross section of 2.
The outer cover was formed to have a thickness of 6 mm.

Further, the present invention is not limited to the above embodiments, and the outer diameter of the insulator is not limited to 12IIn, but may be other values. The same applies if the support wire is not required depending on the cable installation method.

[Function] As explained above, since cross-linked polyethylene is used for the internal insulator and non-halogen flame-retardant polyethylene is used for the outer cover,
It is possible to form a helical leakage coaxial cable that has significantly improved flame retardancy than conventional cables using polyethylene for the insulator and jacket, and does not generate toxic gases.

[Effects] By using the helical leaky coaxial cable of the present invention, radio reception becomes possible in radio wave dead zones in underground malls and tunnels, and because it is flame retardant, it can be used even if an emergency situation such as an accident or fire occurs. However, radio broadcasts can now be interrupted and used for broadcasting accident situations and precautions, as well as for fire and police radio. In addition, since we use non-halogen flame-retardant polyethylene, even if it burns, no toxic gas will be emitted, reducing the risk.

[Brief explanation of the drawing]

The figure is a schematic diagram of a helical leaky coaxial cable. 1...Magnetic core 2...Inner conductor 3...Insulator 4...Outer conductor 5...Support line 6...Outer cover procedure correction Book 1 Indication of the case Patent Application No. 239771 of 1985 2 Name of the invention Flame-retardant spiral leakage coaxial cable 3 Person making the amendment Relationship to the case Patent applicant 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City (225 ) Showa Denshin Co., Ltd. Representative Zennosuke Matsui 4 Agent 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City Sponsored by 6 Column for detailed description of the invention in the detailed description subject to amendment and 7 explanations for the drawings Column. , Contents of amendment (1) The column for detailed explanation of the invention and the column for brief explanation of drawings in the specification are amended as follows. (b) From line 14 to line 18 of page 1 of the specification, “The present invention is suitable for use in underground malls, tunnels, etc.
Regarding leaky coaxial cables. ' shall be amended as follows. "The present invention relates to a flame-retardant helical leaky coaxial cable used for providing information to drivers using the medium wave band in radio wave blind areas such as underground malls and tunnels." (b) Specification, page 1. From line 20 to line 4 on page 3, ``Measures are being taken to make radio waves in tunnels insensitive to police radios in tunnels, underground malls, etc.'' are corrected as follows. . ``Historically, spiral leakage coaxial cables have been used in well-lit areas, and are an excellent medium for leaking radio waves within a limited service area without overreaching like antenna systems or parallel two-wire systems. (c) On page 3, line 5 of the specification, ``used in such a wide range'' should be amended to ``currently widely used.'' (d) "Leaky coaxial cable J" on page 3, line 7 of the specification
Correct the helical leakage with coaxial gaple J. (e) "Coating" on page 3, line 11 of the specification is corrected to "coating." (f) From line 20 on page 3 of the specification to line 5 on page 4, "Currently, the heat resistance and insulation properties of spiral leakage cables...
・(Omitted)...It is quite possible. ' shall be corrected as follows. "On the other hand, as a means of securing mobile radio circuits using the UHF-VHF band in radio wave dead zones such as tunnels or underground malls, antenna methods and methods using leaky coaxial cables have been adopted. The Fire Service Act Enforcement Regulations have been published as part of disaster prevention management in places, and the wiring materials for applicable disaster prevention equipment are required to use heat-resistant, FF1T fire wires. The leaky coaxial cables used are heat resistant type and B flammability type.For these reasons, the heat resistance and II flammability of helical coaxial leaky cables are currently not regulated, but there are restrictions on safety, maintenance, and disaster prevention. It is natural that heat resistance and flammability are required.In J(H) Specification, page 6, lines 1 to 2, [formed so that...] The inner insulator 3 is formed by covering the layer or all of the - part with cross-linked polyethylene so that the inner insulator 3 is formed. (S) “Insulator 3” on page 6, line 2 to line 3 of the specification.
..." is corrected to "internal insulator...". (J) "Outer cover and J" in page 6, line 7 of the specification.
and correct it. (l) Delete [effect] on page 6, line 12 of the specification. (w) From line 13 to line 14 on page 6 of the specification, ``As explained above, ... cross-linked polyethylene is... "Cross-linked polyethylene in one layer or the entire layer," is corrected. (W) Page 7, line 15 of the specification, “3...insulator” is replaced with “3...
...internal insulator". Written amendment to the above procedure ← Kakisho year → 3゛−='″ ~/ 1 Indication of the case 1988 Patent Application No. 239771 2 Name of the invention Flammable helical leakage coaxial cable 3 Person making the amendment 1 ↑ and Relationship: Patent applicant 2-1-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City (225) Showa Electric Wire and Wire Co., Ltd. Representative Zennosuke Matsui 4 Agent 2-1-1-5 Oda Sakae, Kawasaki-ku, Kawasaki City Date of sending of amendment order Date December 6, 1988 6 Target of amendment Procedural amendment dated October 140, 1988. 7 Contents of amendment (1) October 14, 1988 [1 line Procedural amendment “Contents of amendment (to) DJ amend as follows.
It is quite conceivable... (omitted)...6.
shall be corrected as follows. "On the other hand, as a means of securing mobile radio circuits using UHF/VHF bands in radio wave dead zones such as tunnels or underground malls, antenna methods and methods using leaky coaxial cables have been adopted. The Fire Service Act Enforcement Regulations have been published as part of disaster prevention management for locations, and the wiring materials for disaster prevention equipment that are applicable include:
It is mandatory to use heat-resistant and fire-resistant wires. The leaky coaxial cables used in wireless communication auxiliary equipment used for disaster prevention activities are heat-resistant and flame-retardant. Against this background, although the heat resistance and flame retardance of spiral coaxial leaky cables are not currently regulated, it is natural that heat resistance and flame retardance will be required from the aspects of security, maintenance, and disaster prevention. "that's all

Claims (1)

[Claims] In a helical leaky coaxial cable in which an insulator is interposed between an inner helical conductor and an outer helical conductor, radio waves are leaked from the outer helical conductor to integrate a transmitting/receiving antenna and a transmission line, the insulator is cross-linked. polyethylene,
A flame-retardant helical leakage coaxial cable whose jacket is formed from halogen-free flame-retardant polyethylene.