CN212626073U

CN212626073U - Leakage cable

Info

Publication number: CN212626073U
Application number: CN202021581112.8U
Authority: CN
Inventors: 于沅琳; 张海涛; 陈守雨; 虞俊
Original assignee: Shanghai Institute Of Transmission Line (cetc No23 Institute)
Current assignee: Shanghai Institute Of Transmission Line (cetc No23 Institute); CETC 23 Research Institute
Priority date: 2020-08-03
Filing date: 2020-08-03
Publication date: 2021-02-26
Anticipated expiration: 2030-08-03

Abstract

The utility model relates to a leakage cable belongs to the structural design and the processing technology field of cable, and among the mainly used security protection system, as the detection function use. The leakage cable is characterized by comprising a signal transmission section and a signal leakage section; the signal transmission section of the leaky cable is sequentially composed of an inner conductor, an insulating layer, a shielding layer, a high-density metal braid layer, an isolating layer and an outer sheath from inside to outside; the signal leakage section is composed of an inner conductor, an insulating layer, a low-density metal braid layer, an isolating layer and an outer sheath from inside to outside in sequence. The utility model discloses a can make the cable of two kinds of not isostructures, different functions realize on same root continuous cable, reduce the signal loss that the joint brought, reduce cost.

Description

Leakage cable

Technical Field

The utility model relates to a communication cable field specifically is a leakage cable.

Background

The leaky cable is characterized in that the outer conductor is provided with a series of slots or gaps, so that part of energy of electromagnetic waves transmitted in the cable leaks to a space along the cable from the gaps, and an external electromagnetic field can be induced into the cable through the gaps and transmitted to a receiving end, so that the cable simultaneously has dual functions of a transmission line and an antenna. The technology is used in a security system, and people or objects invaded by the outside can be found by capturing the change of an electromagnetic field.

In the prior art, the outer conductor is generally a copper strip or a grooved hole on a corrugated copper tube, and a signal leakage mode is adopted, or a woven outer conductor mode is adopted, and a signal is leaked through a woven gap. However, the above cables are all structured in a consistent manner from end to end, one to end. In the security system, part of a cable is required to transmit signals, and the other part of the cable has a leakage function. The leaky cable not only requires that a part of the length of the cable cannot leak signals outwards on the premise of ensuring the continuous length of the cable, but also is only used for signal transmission, and the remaining part, namely the length needing to be detected, has the function of the leaky cable.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that fill prior art's blank, provide a transmission use of part as the signal, partly leakage cable as signal detection.

The utility model discloses a solve above-mentioned technical problem's technical scheme as follows:

a leaky cable, characterized in that: the leakage cable is composed of a signal transmission section A and a signal leakage section B; the signal transmission section A of the leaky cable consists of an inner conductor 1, an insulating layer 2, a shielding layer 3, a high-density metal braid layer 4, an isolating layer 6 and an outer sheath 7 from inside to outside in sequence; the signal leakage section B is composed of an inner conductor 1, an insulating layer 2, a low-density metal braid layer 5, an isolating layer 6 and an outer sheath 7 from inside to outside in sequence.

Further, the density of the low-density metal braid layer 5 is 30% to 60% of the density of the high-density metal braid layer 4.

Furthermore, the metal braided wires of the high-density metal braided wire 4 and the low-density metal braided wire 5 are made of bare copper wires or tinned copper wires or alloy wires.

Further, the isolation layer 6 is made of a polyester tape, a non-woven fabric or a polyethylene tape.

The beneficial effects of the utility model reside in that: in the past, in the manufacture of the cable of the type, at the junction of the signal transmission section and the leakage section, the signal transmission section cable and the leakage section cable need to be respectively butted through connectors to realize electrical communication. The butt joint mode can increase extra loss at the butt joint position, reduce the overall transmission distance of the cable and simultaneously improve the cost of the cable. The utility model discloses a can make the cable of two kinds of not isostructures, different functions realize on same root continuous cable, reduce the signal loss that the joint brought, reduce cost.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention;

fig. 2 is a transverse cross-sectional view of the signal transmission section a of the present invention.

Fig. 3 is a transverse cross-sectional view of the signal leakage section B of the present invention.

Description of reference numerals:

1. an inner conductor; 2. an insulating layer; 3. a shielding layer; 4. a high density metal braid; 5. a low density metal braid; 6. an isolation layer; 7. an outer sheath; A. a signal transmission section; B. a signal leakage section.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, fig. 2, and fig. 3, the leaky cable provided by the present invention is composed of a signal transmission section a and a signal leakage section B, wherein the signal transmission section a of the leaky cable does not leak signals and is used as a signal transmission cable; the other part, i.e., the signal leakage section B, leaks the signal and is used as a leakage cable.

The signal transmission section A of the cable sequentially comprises an inner conductor 1, an insulating layer 2, a shielding layer 3, a high-density metal braid layer 4, an isolating layer 6 and an outer sheath 7 from inside to outside. In the signal transmission section A, firstly, a layer of polyethylene is foamed and extruded outside the inner conductor 1 of the cable to form an insulating layer 2; then, a shield layer 3 formed of a shield tape is longitudinally wrapped at a fixed length outside the insulating layer 2, and then, when a predetermined length (the length is customized according to the actual required length) is longitudinally wrapped, the longitudinal wrapping of the shield tape is stopped, and a high-density metal braid 4 is braided outside the shield layer 3 to form an outer conductor.

The signal leakage section B is provided with an inner conductor 1, an insulating layer 2, a low-density metal braid layer 5, an isolating layer 6 and an outer sheath 7 from inside to outside. The low-density metal braid 5 is woven outside the insulating layer 2, the weaving pitch is smaller than the length of the signal leakage section B, the number of the woven ingots is reduced to 30% -60% of the number of the ingots by every other ingot in the length range of the whole signal leakage section B from the interface with the signal transmission section A, so that the density of the low-density metal braid 5 is reduced to 30% -60% of that of the high-density metal braid 4, and the optimal implementation proportion is 50%. Then, an isolation layer 6 is formed by wrapping an isolation belt outside the metal braided layer, and finally, an outer sheath 7 is extruded.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.

Best mode, SLYWV-75-7 type leaky coaxial cable:

as shown in fig. 1, 2, and 3, the inner conductor 1 is a bare copper wire; the insulating layer 2 is formed by extruding foamed polyethylene outside the bare copper wire; the shielding layer 3 is longitudinally wrapped by an aluminum-plastic composite tape; the outer conductor of the information transmission section A is a high-density metal braid layer 4, which is formed by weaving 0.15mm copper wires, and the number of weaving ingots is 24; the outer conductor of the information leakage section B is a low-density metal braid 5, and is also braided by 0.15mm copper wires, and the number of braided ingots is 12; the isolation layer 6 is wrapped by a polyester tape; the outer sheath 7 is formed by PVC extrusion. The characteristic impedance of the cable is 75 Ω. The leaky coaxial cable enables cables with two different structures and different functions to be realized on the same continuous cable, so that signal loss caused by the connector is reduced, and cost is reduced.

The above-described embodiments are only intended to illustrate the present invention, and not to limit the present invention, and any person skilled in the art can make various modifications, changes or substitutions without departing from the technical scope of the present invention, so all equivalent technical solutions should be covered by the scope of the present invention.

Claims

1. A leaky cable, characterized in that: the leaky cable is composed of a signal transmission section (A) and a signal leakage section (B) together; the signal transmission section (A) of the leaky cable consists of an inner conductor (1), an insulating layer (2), a shielding layer (3), a high-density metal braid layer (4), an isolating layer (6) and an outer sheath (7) from inside to outside in sequence; the signal leakage section (B) is composed of an inner conductor (1), an insulating layer (2), a low-density metal braid layer (5), an isolating layer (6) and an outer sheath (7) from inside to outside in sequence.

2. A leaky cable as claimed in claim 1, wherein: the density of the low-density metal woven layer (5) is 30% -60% of the density of the high-density metal woven layer (4).

3. A leaky cable as claimed in claim 2, wherein: the metal braided wires of the high-density metal braided layer (4) and the low-density metal braided layer (5) are made of bare copper wires or tinned copper wires or alloy wires.

4. A leaky cable as claimed in claim 1, 2 or 3, wherein: the isolation layer (6) is made of polyester tape, non-woven fabric or polyethylene tape.