RU119929U1 - COMMUNICATION CABLE LOW FREQUENCY WITH FILM-PORO-FILM POLYETHYLENE INSULATION - Google Patents

Abstract

The utility model relates to cable technology, namely, low-frequency communication cables with film-porous-film-polyethylene insulation in a polyethylene sheath, including armored, designed for cabling telephone and telegraph nodes, cable entries and inserts into overhead communication lines, devices of connecting lines between automatic telephone exchange, and also automatic telephone exchange and MTS. Cables can be used for connecting lines using separate circuits in the frequency range up to 552 kHz (for transmitting up to 120 channels of tone frequency). The cable operating voltage is up to 430 V DC or up to 300 V AC with a nominal frequency of 50 Hz. The task was to develop a communication cable with increased reliability, stability and improvement of its electrical characteristics, capacitance, capacitive coupling, capacitive asymmetry, attenuation coefficient), with a reduced mass of the cable, which significantly reduces the complexity of its production, installation and operation. All this is achieved by the use of a low-frequency three-layer film-porous-film polyethylene insulation, poly-ethylene sheath, a screen made of aluminum-polyethylene tape in the design of the communication cable design and a decrease in the pitch of the twisted insulated conductors in fours. The foamed insulation layer leads to a decrease in the dielectric constant of the insulation material and a decrease in the tangent of the dielectric loss angle, and a decrease in material consumption. The process of applying film-porous-film polyethylene insulation is less complicated and time-consuming, which reduces the human factor in production. Replacing the insulation with a moisture-resistant film-porous-film polyethylene made it possible to replace the lead protective sheath in the cables with a polyethylene sheath. Reducing the pitch of the twisted insulated conductive cores in the four in the range from 100 to 300 mm positively affects the stability and improvement of the electrical characteristics of the cable. To protect the cable from external noise, the cable has a screen made of aluminum-polyethylene tape, which is superimposed on the cable with a polyethylene layer outward. When applying a polyethylene sheath, the polyethylene layer of the screen and the polyethylene sheath are welded together, which protects the cable from moisture penetration during mechanical damage during installation and operation. The use of film-porous-film insulation and a polyethylene sheath leads to a decrease in the outer diameter and mass of the cable, which makes the cable lighter, which makes its installation and operation easier and more convenient. In addition, the use of the specified insulation and shell of the claimed utility model significantly reduces the cost of the communication cable. Among other things, replacing materials such as paper and lead in cables with polymeric materials (polyethylene) leads to improved environmental factors in production, improved working conditions, increased productivity and the conservation of natural resources.

Description

The utility model relates to cable technology, namely, low-frequency communication cables with film-porous-film-polyethylene insulation in a polyethylene sheath, including armored, designed for cabling telephone and telegraph nodes, cable entries and inserts into overhead communication lines, devices of connecting lines between automatic telephone exchange, and also automatic telephone exchange and MTS. Cables can be used for connecting lines using separate circuits in the frequency range up to 552 kHz (for transmitting up to 120 channels of tone frequency). The cable operating voltage is up to 430 V DC or up to 300 V AC with a nominal frequency of 50 Hz.

Low-frequency communication cables with film-porous-film polyethylene insulation are mainly used:

TZPpPep - for installation in telephone conduits, in pipes, blocks, collectors tunnels and indoors without mechanical influences on the cable;

TZPpPepB - for laying in soils if the cable is not subjected to significant tensile or compressive forces;

TZPpPepBG - for laying in rooms, tunnels, and collectors, if the cable is not subjected to large tensile forces.

Known low-frequency communication cable with paper-cord insulation in a lead sheath (Belorussov NI and others. Electric cables, wires and cords: Reference book. - M .: Energoatomizdat, 1988, pp. 333, 365).

The use of cord-paper insulation of conductive wires does not allow to obtain stable electrical characteristics of the communication cable. Frequently generated interference currents reduce the quality of information transmission over communication lines. The formation of these interference currents consumes electromagnetic energy transmitted through the circuits that have an effect, which also leads to an increase in losses (attenuation) when transmitting signals over communication cables.

The cord-paper insulation of the cables has a high moisture permeability, therefore, to protect the insulation from moisture during operation, the cable is provided with a sheath of the most moisture-proof material - a lead sheath. But even protecting the insulation with a metal sheath does not exclude, when laying and installing in conditions of high humidity (for example, prolonged rains), drinking moisture from the insulation, which also significantly reduces the electrical characteristics of the communication cable.

In addition, the existing structural elements of the cable with paper-cord insulation in a lead sheath, its dimensions (outer diameter and weight of the cable) complicate its installation and operation.

The task was to develop a communication cable with increased reliability, stability and improved electrical characteristics (capacitance, capacitive coupling, capacitive asymmetry, attenuation coefficient).

The technical result - improving the reliability, stability and quality of the specified electrical characteristics of the cable, reducing the weight of the cable, reducing the complexity in its production, installation and operation - is achieved by using a low-frequency three-layer film-porous-film polyethylene insulation, a polyethylene sheath, an aluminum-polyethylene shield in the communication cable design tape and a decrease in the pitch of the twisted insulated conductive cores in fours.

When using a three-layer film-porous-film insulation made of polyethylene in the cable, the reliability, quality and stability of the electrical characteristics of the communication cable are significantly increased. A foamed insulation layer (porous polyethylene) leads to a decrease in the dielectric constant of the insulation material and a decrease in the dielectric loss tangent, a decrease in material consumption, and the like. The process of applying film-porous-film-polyethylene insulation is less complicated and time-consuming, does not require constant attention from the employee and the level of qualification that is required when applying paper-cord insulation, which reduces the human factor in production.

A decrease in the twist pitch of insulated conductive conductors in quadruples ranging from 100 to 300 mm (the twist steps in all fours are different) also positively affects the stability and quality of the cable’s electrical characteristics (capacitance, capacitive coupling, capacitive asymmetry, attenuation coefficient).

Replacing the cord-paper insulation with a moisture-resistant film-porous-film polyethylene insulation made it possible to replace the lead sheath in the cables with a polyethylene sheath. To protect the cable from external noise, the cable has a screen made of aluminum-polyethylene tape, which is superimposed on the cable with a polyethylene layer outward. When applying a polyethylene sheath, the polyethylene layer of the screen and the polyethylene sheath are welded together, which protects the cable from moisture penetration during mechanical damage during installation and operation.

The use of film-porous-film insulation and a polyethylene sheath leads to a decrease in the outer diameter and mass of the cable, which makes the cable lighter, which makes its installation and operation easier and more convenient. In addition, the use of the specified insulation and shell of the claimed utility model significantly reduces the cost of the communication cable.

Among other things, replacing materials such as paper and lead in cables with polymeric materials (polyethylene) leads to improved environmental factors in production, improved working conditions, increased productivity and the conservation of natural resources.

The cable design is shown on the example of a communication cable brand TZPpPep 4 × 4 × 0.9 in table 1.

Table 1 Options TZPpPep 4 × 4 × 0, 9 Diameter of a single-wire conducting core, mm 0.9 The total thickness of the three-layer insulation, mm 0.5 Twist pitch veins in fours, mm 100-300 The diameter of the central filler four, mm 0.8 Screen thickness from aluminum-polymer tape, mm 0.15 Diameter of a contact wire, mm 0.4 The thickness of the outer shell, mm 1.7

In the attached drawing (Figure 1), the cable is shown in section.

Film-porous-film insulation (2) consisting of three layers is superimposed on single-wire conductive conductors (1). Four insulated cores are twisted into a four (3) around a central filler made of polystyrene filament (4). A twisted four is wrapped in an open spiral with a distinctive synthetic ribbon or thread (5). Fours are twisted into the core of the cable, on which a belt insulation of polymer tapes is applied (6). At the same time, a longitudinal screen of aluminum-polymer tape with overlapping (7) and a sheath of polyethylene (8) are simultaneously applied over the waist insulation. A tinned copper contact wire (9) is laid along the screen.

All materials used in the manufacture of cables comply with the approved regulatory and technical documentation for them.

Cable manufacturing technology is based on the use of industrial cable equipment.

Single-wire conductors made of soft copper wire are made of copper wire according to GOST R 53803-2010. The nominal diameter of the conductive core is 0.90 or 1.2 mm. The cores must not have burrs, cutting edges, breaks, leading to damage to the insulation. Serve to direct the flow of electrical energy.

A three-layer film-porous-film insulation is applied to the conductive conductors, consisting of: the inner layer is made of continuous polyethylene of the brand LE 8706, the middle layer is made of porous (foamed) polyethylene of the brand HE 4873, the outer layer is made of continuous polyethylene of the brand HE 3366. Total thickness insulation is 0.5 mm. The insulation should not have gaps, impurities and inclusions, on the outer surface of the insulation should not be dents, sag and thickenings. The insulation must be airtight.

Four insulated cores are twisted into a four. Four insulated conductors are twisted around a central filler made of polystyrene filament with a diameter of 0.8 mm. The twisting steps of insulated cores in different quadruples vary and should be in the range from 100 to 300 mm. The nominal number of fours in the cables is 1, 3, 4, 7, 12, 14, 19, 27, 37, 52, 61, 80, 102, 114.

In the four, two veins located diagonally form a working pair. The insulation of the veins of the first pair of four must have red and yellow (natural) colors, the second pair - blue (blue) and green.

The twisted four is wrapped in an open spiral with a distinctive synthetic ribbon or thread. The colors of ribbons and threads (distinctive elements) of all fours should be different for fours with different twisting steps. The bright colors of the insulation of the conductors and the distinctive colors of all fours in the cable are used to ensure compliance with electrical safety requirements and facilitate the installation of the cable.

Fours are twisted into the core of the cable with a twisting step of no more than 30 diameters along the cable twist. Adjacent fours in the cable core have different twisting steps. Belt insulation made of polymer tapes is superimposed on the core. The use of paper tapes is not allowed, since when pumping with air and installing the cable, the paper absorbs moisture, which significantly degrades the electrical characteristics of the cable.

On top of the belt insulation, a longitudinal screen of 0.15 mm thick aluminum-polymer tape with overlapping and a polyethylene sheath is simultaneously applied. The shell thickness is 1.7 mm. A tinned copper contact wire with a diameter of at least 0.4 mm is laid along the screen.

In the cables of TZPpPepBB and TZPpPepBBG brands, protective covers in accordance with GOST 7006-72 types are applied to the polyethylene sheath: for cables with protective cover type B - from the pillow, two steel tapes with a nominal thickness of 0.5 mm and an external protective cover; for cables with a protective cover like BG - from a pillow and two steel tapes with previously applied zinc coating.

The tests of the claimed model confirmed its compliance with the requirements for low-frequency communication cables, and the specified electrical parameters:

Name of parameters Electrical parameters famous cable brand TZ TZPpPep brand cables 1. Working capacity. nF / km - 32.11-32.23 2. Capacitive communications. pF, not more than: K1 260 200 K9 - K12 180 115 3. Capacitive asymmetry, pF, no more 1000 440

Name of parameters Electrical parameters famous cable brand TZ TZPpPep brand cables 4. The attenuation coefficient at a frequency of 150 kHz, dB / km - 2.65 5. The wave resistance. Ohm 160 ± 10 155

Due to the fact that the structural elements are three-layer film-porous-film insulation made of polyethylene, a reduced pitch of twisted insulated conductive conductors in quadruples ranging from 100 to 300 mm, a polyethylene sheath and a screen made of aluminum-polyethylene tape, the declared communication cables significantly increased reliability, quality and stability of electrical characteristics; the adhesion between the conductor and the insulation increased significantly and moisture penetration between the insulation and the conductor was excluded due to the absence of open pores around the latter; the dielectric constant of the insulation material is significantly reduced, the tangent of the dielectric loss angle is reduced, and the material consumption is reduced. A less time-consuming and more advanced process of applying film-porous-film polyethylene insulation and polyethylene sheath reduces the human factor in production. Reducing the pitch of the twist of conductive conductors has a positive effect on improving the electrical parameters of the cable, and reducing the mass of the cable greatly facilitates its installation and operation. The use of a screen made of aluminum-polyethylene tape allows you to protect the cable from external interference. Welding the polyethylene layer of the screen with a polyethylene sheath protects the cable from moisture penetration during mechanical damage during installation and operation.

Claims (4)

1. Low-frequency communication cable with film-porous-film polyethylene insulation, consisting of copper single-wire insulated conductors twisted into fours from 1 to 114 in number, which are twisted into the cable core, with belt insulation and sheath, characterized in that it is laid on conductive conductors three-layer film-porous-film insulation made of polyethylene, while the outer and inner layers are made of continuous polyethylene, the middle layer is made of porous (foamed) polyethylene, the belt insulation is made of polymer tapes , the sheath is made of polyethylene, and the twisting steps of the insulated cores in the fours are different and range from 100 to 300 mm. 2. The cable according to claim 1, characterized in that a shield of aluminum-polyethylene tape is laid over the belt insulation and a tinned copper contact wire with a diameter of at least 0.4 mm is laid along the screen. 3. The cable according to claims 1 and 2, characterized in that a cushion, armor from two steel tapes and an external protective cover are applied over the shell. 4. The cable according to claims 1 and 2, characterized in that a cushion and armor of two steel tapes with a pre-applied zinc coating are applied over the shell.