RU2462801C1 - Method of protecting optical cable from freezing water in protective polymer pipe and backup thereof in case of damage - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention can be used to protect an optical cable laid in a protective polymer pipe of an intercity cable-conduit line from the effect of freezing water in the pipe and backing up the optical cable in case of damage. A protective tube is laid together with the cable in the protective polymer pipe, said tube having diameter selected based on the condition D_PT≥4·D_MC, where D_3T is the inner diameter of the protective tube, D_MC is the outer diameter of the optical microcable of the cable insertion, wherein the ends of the protective tube enter inspection devices and are sealed, and in order to back up the optical cable in case of damage, an optical microcable of the cable insertion is laid on the section between the inspection devices on which the damage is located in the protective tube.

EFFECT: reduced probability of damage to the optical cable by freezing water, as well as possibility of backing up the optical cable when damaged by laying a cable insertion on the section between inspection devices.

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Description

The invention relates to fiber-optic communication technology and can be used to protect an optical cable laid in a protective polymer pipeline of interurban cable ducts (MKK) from the effects of freezing water in the pipeline and redundancy of the optical cable if it is damaged.

A known method [1] of protecting an optical cable laid in the ground from external influences, including the action of freezing water, namely, that the optical cable is laid in a protective polymer pipe. However, if the tightness of the pipeline is violated, water accumulates in it, the channel becomes silted. When water freezes in the pipeline, the cable is subjected to crushing loads. If the cable is damaged, it cannot be removed from the silt channel with frozen water, and during repair work on the line for laying a temporary or permanent cable insert, a spare free channel (pipeline) is required. Otherwise, a significant amount of expensive earthwork is required. There is a method [2] of protecting a communication cable from freezing water in a cable duct, damping elements (waterproofing plaits made of porous rubber or rubber technical tubes sealed at the ends) are laid parallel to the cable in the cable duct, the diameter of which satisfies the condition :

where D _E is the outer diameter of the damping element;

n is the number of laid damping elements;

D _T is the inner diameter of the cable channel;

D _K is the outer diameter of the cable;

k _y - coefficient of compaction of the damping element;

k _P - coefficient of expansion of water during freezing.

According to [3], the total diameter of the elements (cables, damping elements) laid in the protective polymer pipeline must not exceed (0.5 ... 0.75) · D _T. In this case, condition (1) is practically impossible.

A known method [4] of protecting an optical cable from the effects of freezing water in a protective polymer pipe is that, together with the cable, a protective pipe attached to it with a bandage or spirally imposed wire is laid together with the cable. Moreover, at points located along its length with a certain constant step, the protective tube is pinched. The diameter of the protective tube is significantly smaller than the value determined from formula (1), because of which the probability of damage to the optical cable as a result of freezing water in the pipeline increases. Moreover, in case of damage to the cable, it cannot be removed from the protective pipeline with frozen water, and for laying a temporary or permanent cable insert during repair work on the line, a redundant backup protective pipe must be laid nearby. Otherwise, a significant amount of expensive earthwork is necessary.

The essence of the invention is the expansion of the scope.

This essence is achieved by the fact that according to the method of protecting an optical cable from freezing water in a protective polymer pipe and backing it up in case of damage, the protective pipe being laid together with the cable in a polymer polymer pipe, characterized in that the diameter of the protective pipe is selected from conditions D _{ST MK} ≥4 · D where D _GP - inner diameter of the protective tube, a D _MK - outside diameter of the optical cable insertion microcable, the ends of the protective tube outputted to the inspection apparatus and ger they are metalized, and if the optical cable is damaged for redundancy in the area between the viewing devices where the damage takes place, an optical micro cable of the cable insert is laid in the protective tube.

Figure 1 presents the structural diagram of a device for implementing the proposed method.

The apparatus 1 comprises an optical cable laid in the protective pipe 2, a protective tube 3 with a diameter D _ST ≥4 · D _MK sandwiched in the protective pipe 2 together with the optical cable 1, the ends of which are derived in the inspection device 4 and sealed, and the cable insertion microcable 5, laid in the protective tube 3 when the optical cable 1 is damaged for redundancy in the area between the viewing devices 4, where the damage takes place.

The method is as follows. A protective tube 3 laid along with the optical cable 1 in the protective conduit 2, the ends of which are led out to the inspection devices 4 and sealed, reduces the pressure when water freezes in the protective conduit 2 and, thereby, the probability of damage to the optical cable. The diameter D of the protective tube _ST ≥4 · D _MC enables napkin therein microcable cable insertion is damaged optical cable for its reservation on the viewing portion between devices on which the damage occurs, even if the compression of the protective tube under the action of freezing water 50% .

Compared with the prior art in the present process the protection tube not only reduces the likelihood of damage to the protective pipe of the optical cable under the action of freezing water, but also due to the choice of the diameter D _ST ≥4 · D _MK redundancy enables the optical cable during its

damage by laying the micro-cable of the cable insert in the area between the viewing devices where the damage takes place. Using the method of pneumatic laying, the microcable of the cable insert can be blown into the protective tube at a distance of 2 km or more. Thus, the proposed method expands the scope in comparison with the prototype.

LITERATURE

1. Griffin V. Laying optical cables in tubes. - Plumettaz, 1993 .-- 138 p.

2. Lyakhovich I.F., Cancer S.M., Polyakov S.T. Cable protection from damage by freezing water // Communication Bulletin, 1985, N9, p.30-31.

3. Instructions for laying and mounting an optical cable in SILICORE PVP tubes. - M.: SSKTB-TOMASS, 1998 .-- 134 p.

4. Patent JP 6018721.

Claims (1)

A method of protecting an optical cable from the effects of freezing water in a protective polymer pipe and backing it up in case of damage, which consists in laying a protective pipe together with the cable in a protective polymer pipe, characterized in that the diameter of the protective pipe is selected from the condition D _ST ≥4 · D _MK, where _ST D - inner diameter of the protective tube, a D _MK - outside diameter of the optical cable insertion microcable, the ends of the protective tube outputted to the inspection apparatus and sealed, and if damaged optical cab A reservation for it in the area between the viewing device in which the damage occurs in the protective tube paving microcable optical cable insertion.