CN114283975A

CN114283975A - Flexible mineral substance insulation pre-branch fireproof cable

Info

Publication number: CN114283975A
Application number: CN202111666230.8A
Authority: CN
Inventors: 林耿郁; 陈文珊
Original assignee: Guangzhou Youfeng Wire And Cable Co ltd
Current assignee: Guangzhou Youfeng Wire And Cable Co ltd
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2022-04-05

Abstract

The utility model discloses a flexible mineral substance insulated pre-branched fireproof cable, which comprises: trunk cable and branch line cable the junction of trunk cable and branch line cable still is provided with fixing device, fixing device includes: the cable fixing device comprises a protective box, a C-shaped clamp, two first reinforcing cable clamps and a plurality of second reinforcing cable clamps; the cable body of the trunk cable, the cable body of the branch cable, the joint of the trunk cable and the branch cable, the first reinforcing cable clamp and the second reinforcing cable clamp in the protective box are completely covered by the injection-molded cured substance. The tensile strength of the branch connecting part of the mineral prefabricated branch cable is synergistically improved through three aspects, the tensile strength effect is obviously improved, and the mineral prefabricated branch cable has sealing performance.

Description

Flexible mineral substance insulation pre-branch fireproof cable

Technical Field

The utility model belongs to the technical field of mineral cables, and particularly relates to a flexible mineral insulating pre-branched fireproof cable.

Background

The prefabricated branch cable has the advantages of low power distribution cost, short site construction period, no limitation of space and environment conditions of a construction site and the like. The cable is widely applied to residential buildings, office buildings, commercial buildings and the like, and is used as a main cable and a trunk cable for power supply and distribution in high-rise buildings. At present, the state issues the related standard of JB/T10636-.

The mineral prefabricated branch cable is connected through the main line and the branch line by means of crimping, and for this purpose, the sheath and the insulating material of the connecting part need to be removed. The insulation of the mineral insulated cable is made of mineral materials, and if a little moisture enters the cable, the insulation performance of the cable is reduced sharply, and the cable is broken down. Therefore, the development focus of the mineral pre-branching cable in the field mainly focuses on the waterproof and water-blocking design of the branch connection part.

The utility model discloses a mineral-insulated fireproof water-blocking pre-branch cable, which comprises a main cable, branch cables and a connector, wherein the branch cables are connected to the main cable through the connector, the main cable and the branch cables are identical in structure and respectively comprise a conductive wire core, an insulating layer, a copper metal isolating sleeve and an outer sheath from inside to outside, the connector comprises a C-shaped copper press-connection ring, a mineral insulating layer, a connector copper metal isolating layer, a water-blocking layer and a connector outer sheath which are sequentially arranged at the connection position of the main cable and the branch cables from inside to outside, and thermal shrinkage waterproof sleeves are respectively arranged at the connection ends of the connector, the main cable and the branch cables. The utility model claims to thoroughly solve the problem of frequent operation faults such as cable breakdown caused by water inflow of the cable and is convenient to popularize and use.

However, the applicant researches and discovers that the existing mineral prefabricated branch cable generally forms a branch connecting body at the branch connecting part in an injection molding mode so as to protect the connecting part of the trunk line and the branch line, however, the tensile strength of the branch connecting body obtained by the conventional injection molding method is poor, when the prefabricated branch cable is laid, the phenomenon that the trunk line and the branch line are connected unstably due to the tensile force of the branch line or multiple bending exists, the use of the cable is influenced, and the branch line is broken at the branch connecting part in serious cases.

Chinese utility model patent with publication number CN201449769U discloses a prefabricated branch cable of improved generation, including leader cable and the branch cable rather than being connected, the junction of leader cable and branch cable is equipped with around the covering outward, the welding is in the same place between the conductor of leader cable and the conductor of branch cable. Compared with the crimping mode, the structure of the utility model omits the crimping accessories, and has more compact structure and higher strength. The tensile strength of the cable is improved to 110 percent from 80 percent before connection by a crimping method, and the fastening performance is better.

The utility model discloses a chinese utility model patent that publication number is CN213601662U discloses a prefabricated branch cable, including the protection box, the bottom of protection box is provided with the main push-towing rope, the top of main push-towing rope runs through to the top of protection box, the left side of main push-towing rope and the inner chamber intercommunication that is located the protection box have a cable, the one end that the main push-towing rope kept away from runs through to the top of protection box, the main push-towing rope all includes the basic unit with a cable, adhesive fixedly connected with insulating layer is passed through on the surface of basic unit, adhesive fixedly connected with enhancement layer is passed through on the surface of insulating layer. It has solved the lower tensile influence of external force of current prefabricated branch cable intensity and has appeared the damaged problem of fracture easily down through setting up protection box, basic unit, insulating layer, enhancement layer, tensile layer, fire-retardant layer, corrosion resistant layer, ageing resistant layer, knob, threaded rod, clamp plate, fishback, thermoplastic polyurethane elastomer layer and butadiene-acrylonitrile rubber layer, this prefabricated branch cable possesses the tensile advantage of the high stretch-proofing of intensity.

The utility model discloses a method for manufacturing a prefabricated branch cable and the prefabricated branch cable, wherein the publication number of the Chinese patent with CN113724927A is as follows: a1, stripping an insulating layer and a protective layer at the connecting part of a trunk cable and stripping an insulating layer and a protective layer at the connecting end of a branch cable; a2, connecting the conductors of the branch line cable connecting end to the conductors of the main line cable connecting part in parallel; a3, clamping a C-shaped connector to a joint between a branch line cable and a main trunk line cable; a4, wrapping an insulating wrapping layer at the connection part of the trunk cable; a5, transferring the trunk cable, the branch cable, the C-shaped connector and the insulating wrapping layer into an injection mold, injecting hot-melted polyolefin into the injection mold through a screw injection molding machine, and curing to form a branch connector after pressure maintaining and cooling; a6, opening an injection mold, and taking out the prefabricated branch cable which is manufactured; the advantage is effectively improving the tensile strength and the sealing performance of the junction of the trunk line and the branch line.

The prior art means are not directed at mineral insulated cables, and the technical means are more conventional means, and are difficult to be suitable for the preparation of prefabricated branches of mineral insulated cables. Meanwhile, although the tensile strength of the prefabricated branch cable is improved to a certain extent, the use requirement of the mineral insulated cable cannot be met far away, and the tensile design of the branch connecting part needs to be improved.

Disclosure of Invention

The utility model aims to solve the technical problems that the branch connecting part of the existing mineral prefabricated branch cable is low in tensile strength and easy to damage a connecting structure or sealing water resistance performance due to external force in the laying process, and the like, and provides a flexible mineral insulating pre-branch fireproof cable.

In order to solve the problems, the utility model is realized according to the following technical scheme:

the utility model provides a flexible mineral insulated pre-branched fireproof cable, which comprises:

a main cable, wherein a cable body of the main cable is provided with a cut part, and the cut part only comprises a conductor part of the main cable;

the tail end of the branch cable is provided with a connecting wire core, and the connecting wire core is wound and fixedly connected on the conductor part of the cut part;

still be provided with fixing device in the junction of trunk cable and branch cable, fixing device includes:

the protection box completely wraps the connection part of the trunk cable and the branch cable; and a cover plate arranged in the protective box,

the C-shaped clamp is used for tightly clamping the connecting part of the trunk cable and the branch cable;

two first reinforcing cable clamps respectively clamped on cable bodies of the main cable adjacent to left and right of a cut part, wherein the cut part is positioned between the two first reinforcing cable clamps;

the second reinforcing cable clamps are clamped on the cable body of the branch cable;

the cable body of the trunk cable, the cable body of the branch cable, the joint of the trunk cable and the branch cable, the first reinforcing cable clamp and the second reinforcing cable clamp in the protective box are completely covered by the injection-molded cured substance.

Preferably, the first reinforcing cable clamp and the second reinforcing cable clamp are both C-shaped in cross section, and a plurality of conical punctures are distributed on the inner surfaces of the first reinforcing cable clamp and the second reinforcing cable clamp and used for penetrating into a sheath of a cable.

Preferably, the second reinforcing cable clamp comprises a C-shaped body and a plurality of tapered punctures arranged on the inner surface of the C-shaped body;

the length of C type main part is 80 ~ 100mm, the thickness of C type main part is 8 ~ 15 mm.

Preferably, the outer surface of the C-shaped main body is provided with a plurality of semi-annular cutting grooves which are sequentially arranged at equal intervals along the axis of the C-shaped main body; the outer surface of the C-shaped main body is uneven due to the semi-annular grooves, so that the C-shaped main body and the injection-molded condensate form a chimeric structure.

Preferably, a high-temperature resistant water-blocking tape is arranged between the inner surface of the first reinforcing cable clamp and the outer surface of the main cable, and before the first reinforcing cable clamp is connected with the cable body of the main cable, the high-temperature resistant water-blocking tape is wrapped on the cable body corresponding to the main cable;

a high-temperature resistant water-blocking tape is arranged between the inner surface of the second reinforcing cable clamp and the outer surface of the branch cable; before the second reinforcing cable clamp is connected with the cable body of the branch cable, a high-temperature-resistant water-blocking tape is wrapped on the cable body corresponding to the branch cable, and the length of a wrapping area of the high-temperature-resistant water-blocking tape on the branch cable is not less than 80 mm.

Preferably, before the protective box is filled with the injection-molded cured product, a coating cushion layer is arranged at the exposed part of the cable body at the joint of the trunk cable and the branch cable; the coating cushion layer is formed by sequentially wrapping a mica tape, a high-voltage insulating tape, a waterproof tape and a protective tape on two sides of the exposed part of the cable body.

Preferably, the injection molding condensate is formed by injection molding and filling of a low-smoke halogen-free flame-retardant polyolefin material.

Preferably, the main cable comprises a stranded cable core, an inorganic filling layer, a high-strength protective layer, a copper sheath, a high-temperature-resistant heat-insulating layer and an outer sheath which are sequentially arranged from inside to outside;

each cable of the main cable comprises a conductor, a mineral insulation fire-resistant layer and an insulation layer which are sequentially arranged from inside to outside.

Preferably, the branch cable comprises a stranded cable core, inorganic fiber filler, a copper sheath and an outer sheath which are sequentially arranged from inside to outside;

each cable of the branch cable comprises a conductor and an inorganic insulating wrapping tape which are sequentially arranged from inside to outside.

Compared with the prior art, the utility model has the beneficial effects that:

according to the flexible mineral substance insulation pre-branch fireproof cable, on the first hand, the C-shaped clamp is arranged at the joint of the trunk cable and the branch cable, the C-shaped clamp serves as a structure for improving the tensile property, and the tensile property of the joint is enhanced by tightly clamping the two cables at the branch connecting part.

In the second aspect, the protection box is filled with compact injection-molded condensate which fully permeates into structures and gaps formed by all parts of the branch connecting part, the injection-molded condensate is cooled and solidified and then is combined with the branch connecting part to form a physical fixed connection structure into a whole, and under the wrapping and reinforcement of the protection box, a second physical structure for improving the tensile property is formed, so that the tensile strength of the branch connecting part is improved; and simultaneously has excellent sealing performance.

In a third aspect, the utility model innovatively clamps a plurality of second reinforcing cable clamps on the cable body of the branch cable, and the end faces of the second reinforcing cable clamps have a certain thickness so as to form a rugged structure on the surface of the cable body of the branch cable, and the surface of the branch cable and the solidified injection-molded solidified substance form a physical embedded structure by matching with dense filling and cooling solidification of the injection-molded solidified substance, and the sheath of the branch cable and the injection-molded solidified substance are wedged and jointed with each other through the embedded structure, so that the tensile strength is improved. At the in-process of laying cable, when the branch line cable received to pull, the gomphosis structure can disperse the stress that the branch line cable produced because of pulling, avoids stress mainly to concentrate on the connection sinle silk of branch line cable, solves the cracked problem of connection sinle silk because of the stress is too big.

The tensile strength of the branch connecting part of the mineral prefabricated branch cable is synergistically improved through three aspects, the tensile strength effect is obviously improved, and the mineral prefabricated branch cable has sealing performance.

Drawings

Embodiments of the utility model are described in further detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of a branch connection of a flexible mineral insulated pre-branch fireproof cable according to the present invention;

FIG. 2 is an assembly schematic view of a branch connection site of the flexible mineral insulated pre-branch fireproof cable of the present invention;

FIG. 3 is a schematic sectional view of a branch connection portion of the flexible mineral insulated pre-branch fireproof cable of the present invention;

FIG. 4 is a schematic cross-sectional view of a main cable and a first reinforcing cable clamp of the flexible mineral insulated pre-branch fireproof cable of the present invention;

FIG. 5 is a cut-away schematic view of a feeder cable and a second reinforcing cable clamp of the flexible mineral insulated pre-branch fireproof cable of the present invention;

in the figure:

10-main cable, 11-cut part;

20-branch cable, 21-connecting wire core;

30-a protection box;

a 40-C clip;

50-a first reinforcing cable clamp;

60-a first reinforcing cable clamp;

70-injection molding of a cured product;

80-chimeric structure;

90-high temperature resistant water-blocking tape.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

In the field, the current national standard and the line standard relate to 3 standards of mineral insulated cable products. The mineral insulated cables of the different product standards are shown in table l.

Table 1 mineral insulated cable of different product standards

The utility model mainly provides a YTTW series flexible mineral substance insulation pre-branching fireproof cable. The applicant researches and discovers that the related standards of JB/T10636-2006 copper core plastic insulation prefabricated branch cable with rated voltage of 0.6/1kV (Um is 1.2kV) are issued by the country aiming at the pre-branch cable at present, but no related national standards are issued for the mineral prefabricated branch cable at present. However, the research and development focus of the mineral pre-branch cable in the field mainly focuses on the waterproof and water-blocking design of the branch connection part. However, when the mineral insulation prefabricated branch cable is laid, the tension or repeated bending of the branch lines causes unstable connection of the trunk line and the branch lines, the use of the cable is influenced, and the branch lines are broken at branch connection parts seriously, so that the cable is scrapped. The conventional pre-branching technology is not specific to the mineral insulated cable, and cannot well improve the tensile strength of the branch connection part of the mineral insulated cable, so that the use requirement is difficult to meet.

Example one

Therefore, the object of the patent is to provide a flexible mineral substance insulation pre-branch fireproof cable with good tensile strength performance at the branch connection part.

As shown in fig. 1 to 5, it is a preferred structure of a flexible mineral insulation pre-branch fireproof cable according to the present invention.

As shown in fig. 1, the flexible mineral-insulated pre-branching fireproof cable comprises a trunk cable 10 and branch cables 20. The manufacturing process of the flexible mineral insulation pre-branching fireproof cable comprises a plurality of steps, mainly including conductor connection of the trunk cable 10 and the branch cable 20, insulation of the connection part and outer protection treatment.

The body of the main cable 10 is provided with a cut-out portion 11, and the cut-out portion 11 includes only a conductor portion of the main cable 10. The tail end of the branch cable 20 is provided with a connecting wire core 21, and the connecting wire core 21 is wound and fixedly connected on the conductor part of the cut part 11 to realize the connection of the conductor.

For the insulation and infrared treatment of the connection part, a fixing device is arranged at the connection part of the trunk cable 10 and the branch cable 20, and the insulation, sealing, water blocking and tensile properties of the branch connection part of the flexible mineral insulation pre-branch fireproof cable are realized through the fixing device.

As shown in fig. 2, the fixing means includes a protective case 30, a C-shaped clip 40, two first reinforcing cable clips 50 and a plurality of second reinforcing cable clips 60. Wherein C-clamp 40, first reinforcing cable clamp 50 and second reinforcing cable clamp 60 are all shown within protective pocket 30 when making a drop cable. Specifically, the protection box 30 is filled with a dense injection-molded cured product 70, and the injection-molded cured product 70 completely covers the cable body of the trunk cable 10, the cable body of the branch cable 20, the joint between the trunk cable 10 and the branch cable 20, the first reinforcing cable clamp 50, and the second reinforcing cable clamp 60 in the protection box 30.

The compact injection molding condensate is filled in the protective box, the injection molding condensate fully permeates into a structure and a gap formed by each part of the branch connecting part, the injection molding condensate is cooled and solidified and then forms a physical fixed connection structure with the branch connecting part to be combined into a whole, and under the wrapping and reinforcing of the protective box, a physical structure for improving the tensile property is formed, so that the tensile strength of the branch connecting part is improved; and simultaneously has excellent sealing performance.

As shown in fig. 3, the protection box 30 of the present invention completely covers the connection between the trunk cable 10 and the branch cable 20.

In one embodiment, the protection box 30 includes an upper box and a lower box, the upper box and the lower box are connected to each other, and the protection box 30 is made of copper or aluminum alloy. As an embodiment, the upper case and the lower case may be fixedly connected by bolts, or may be fixed by welding, and the present invention is not limited thereto.

Specifically, the upper box body and the lower box body cover the cut-out part of the trunk cable and the conductor adjacent to the cut-out part, the connecting wire core of the branch cable and the cable body adjacent to the connecting wire core, so that the cut-out part of the trunk cable and the cable body adjacent to the cut-out part, the connecting wire core of the branch cable and the cable body adjacent to the connecting wire core are all arranged in the box cavity of the protection box. The protection box is provided with a through hole for the main cable and the branch cable to penetrate through, an injection molding hole is reserved in the protection box, and the injection molding hole is communicated with a box cavity of the protection box.

As shown in fig. 2, the C-shaped clip 40 of the present invention wraps around the junction of the trunk cable 10 and the branch cable 20, and the C-shaped clip 40 is used to tightly clip the junction of the trunk cable 10 and the branch cable 20.

The C-shaped clamp is made of metal materials, the cross section of the C-shaped clamp is C-shaped, and the C-shaped clamp is known by those skilled in the art. Specifically, the length of the C-shaped clamp is smaller than the length of the conductor section of the notch part, and the length of the C-shaped clamp is slightly larger than the winding length of the connection part. Specifically, the C-shaped clamp is wrapped on the joint of the trunk cable and the branch cable and abutted against the connection wire core in a winding state. One skilled in the art can compress the C-clamp with hydraulic pliers so that the C-clamp grips the trunk cable and the branch cable for further fixation.

In order to improve the tensile strength of the branch connection part of the flexible mineral insulation pre-branch fireproof cable, the C-shaped clamp 40 is arranged at the connection part of the trunk cable 10 and the branch cable 20, the C-shaped clamp 40 serves as a first structure for improving the tensile performance, and the tensile performance of the connection part is enhanced by tightly clamping the two cables at the branch connection part.

As shown in fig. 2, two first reinforcing cable clamps 50 according to the present invention are respectively clamped to cable bodies of the main cable 10 adjacent to left and right of the cut-out portion 11, and the cut-out portion 11 is located between the two first reinforcing cable clamps 50.

When the main cable 10 is branched, all sheaths except the conductor need to be removed, and only the conductor remains in the notch 11 of the main cable 10. Since many cables are vertically laid, stress is concentrated on the notch 11 of the main cable 10 during the laying of the main cable 10, and the conductor is likely to be defective. Therefore, the first reinforcing cable clamp 50 is innovatively clamped on the cable body of the main cable 10, and the end face of the first reinforcing cable clamp 50 has a certain thickness, so that a rugged structure is formed on the surface of the cable body of the main cable 10, and the surface of the main cable 10 and the solidified injection-molded solidified material 70 form a physical embedded structure 80 by matching with dense filling and cooling solidification of the injection-molded solidified material 70. In the process of laying the cable, when the main cable 10 is pulled, the fitting structure 80 can disperse the stress generated by pulling the main cable 10, and can disperse the stress to the sheath of the main cable 10, thereby preventing the stress from being mainly concentrated on the conductor of the main cable 10.

In one embodiment of the utility model, as shown in fig. 2 and 3, the cable is provided with a second reinforcing cable clamp 60 which clamps onto the body of the spur cable 20.

When the branch cable 20 is made to be branched, all sheaths at the end part need to be removed, so that only the connecting wire core 21 is left at the end part of the branch cable 20. In the laying process of the branch cable 20, the branch cable 20 needs to be pulled or bent for multiple times, the connection wire core 21 is the root of the branch cable 20 and is used as a part for connecting the main cable 10, and the connection wire core 21 is subjected to stress concentration in the laying process such as pulling due to the elimination of the sheath. Therefore, the plurality of second reinforcing cable clamps 60 are innovatively clamped on the cable body of the branch cable 20, the end face of each second reinforcing cable clamp 60 is provided with a certain thickness, so that a rugged structure is formed on the surface of the cable body of the branch cable 20, the surface of the branch cable 20 and the solidified injection-molded solidified material 70 form a physical embedded structure 80 by matching with dense filling and cooling solidification of the injection-molded solidified material 70, and the sheath of the branch cable 20 and the injection-molded solidified material 70 are wedged and jointed with each other through the embedded structure 80, so that the tensile strength is improved.

In the process of laying the cable, when the branch cable 20 is pulled, the embedded structure 80 can disperse the stress generated by pulling the branch cable 20 to the sheath of the branch cable 20, so as to avoid the stress from being mainly concentrated on the connecting wire core 21 of the branch cable 20, and solve the problem that the connecting wire core 21 is broken due to overlarge stress.

The tensile strength of the branch connecting part of the mineral prefabricated branch cable is synergistically improved through the three aspects, the tensile strength effect is obviously improved, and the mineral prefabricated branch cable has sealing performance.

In a specific implementation, the injection molding cured product 70 is formed by injection molding and filling of a low-smoke halogen-free flame-retardant polyolefin material, so that the insulation performance and the flame retardant performance of the cable are fully guaranteed. The low-smoke halogen-free flame-retardant polyolefin material is high in fluidity, convenient to inject, free of gap as far as possible to fill, and compact to fill.

Example two

The second embodiment provides a flexible mineral insulated pre-branched fireproof cable, which has the same structure and principle as those of the first embodiment, except that the second embodiment provides a specific implementation structure of the first reinforcing cable clamp 50 and the second reinforcing cable clamp 60 on the basis of the first embodiment.

The cross sections of the first reinforcing cable clamp 50 and the second reinforcing cable clamp 60 are both C-shaped, and a plurality of conical punctures are distributed on the inner surfaces of the first reinforcing cable clamp 50 and the second reinforcing cable clamp 60 and used for penetrating into sheaths of cables. Because the cable body is mostly cylindrical circumferential structure, and adopt the design of the cable clamp of toper puncture, can fix in the cable body outside well, the cable clamp is difficult to mutual displacement with the cable body and slides to guarantee the structural strength of cable clamp and cable body and with the effect of stress dispersion.

In one embodiment, the first and second reinforcing

clips

50 and 60 are made of a metal material, such as aluminum or aluminum alloy, which has the advantages of light weight and high strength.

Specifically, to ensure the connection stability of the second reinforcing cable clamp 60 with the branch cable 20, in one implementation, the second reinforcing cable clamp 60 includes a C-shaped main body and a plurality of tapered punctures disposed on the inner surface of the C-shaped main body; the length of C type main part is 80 ~ 100mm, the thickness of C type main part is 8 ~ 15 mm.

In a preferred embodiment, the length of the C-shaped body is 80mm, and the thickness of the C-shaped body is 8 mm.

Specifically, the pre-branch cable is a cable that is prefabricated by a cable manufacturer according to a user design drawing when the main cable 10 is produced. The branch lines are pre-manufactured in the trunk cable 10 and the branch cable 20, and the parameters such as the sectional size and the length are determined according to the design requirements, for this reason, the specific size design of the first reinforcing cable clamp 50 and the second reinforcing cable clamp 60 can be adjusted by those skilled in the art according to the specific design requirements. The utility model is not limited.

As shown in fig. 2 and 5, in a preferred structure, the outer surface of the C-shaped body is provided with a plurality of semi-annular cutting grooves, and the plurality of semi-annular cutting grooves are sequentially arranged at equal intervals along the axis of the C-shaped body; the plurality of semi-annular grooves make the outer surface of the C-shaped body uneven, so that the C-shaped body and the injection-molded cured object 70 form a fitting structure 80.

Through the design, the contact area of the second reinforcing cable clamp 60 and the injection-molded cured object 70 is increased, and the number of the embedded structures 80 formed by the second reinforcing cable clamp 60 and the injection-molded cured object 70 is increased, so that the effect of stress dispersion is improved. On the other hand, the contact area between the two is increased, the strength of the fixed structure of the second reinforcing cable clamp 60 and the injection molding condensate 70 is better, and the tensile property is more favorably improved.

EXAMPLE III

The third embodiment provides a flexible mineral insulation pre-branch fireproof cable, which has the same structure and principle as those of the second embodiment, except that the second embodiment provides a specific implementation structure for combining the trunk cable 10 with the first reinforcing cable clamp 50 and combining the branch cable 20 with the second reinforcing cable clamp 60.

As shown in fig. 4, a high temperature resistant water-blocking tape 90 is disposed between the inner surface of the first reinforcing cable clamp 50 and the outer surface of the main cable 10, and before the first reinforcing cable clamp 50 is connected to the cable body of the main cable 10, the high temperature resistant water-blocking tape 90 is wrapped around the cable body corresponding to the main cable 10.

As shown in fig. 5, a high temperature resistant water blocking tape 90 is disposed between the inner surface of the second reinforcing cable clamp 60 and the outer surface of the branch cable 20; before the second reinforcing cable clamp 60 is connected with the cable body of the branch cable 20, a high-temperature resistant water-blocking tape 90 is wrapped on the cable body corresponding to the branch cable 20, and the length of the wrapping area of the high-temperature resistant water-blocking tape 90 on the branch cable 20 is not less than 80 mm.

According to the utility model, the structure of the sealing and protecting layer is formed by the injection molding condensate 70, in order to enhance the water resistance performance of the branch connecting part, before injection molding, 5-8 layers of high temperature resistant water-blocking tapes 90 are respectively overlapped and wound on two cable bodies of the trunk cable 10 close to the notch part 11 and the cable bodies of the branch cables 20 close to the connecting wire cores 21, and then the first reinforcing cable clamp 50 and the second reinforcing cable clamp 60 are used for clamping and fixing.

Through the design, the phenomenon that after the branch cable is used for a long time, a gap is formed between the injection molding condensate 70 and the surface of the cable body due to external factors, and a gap is formed between the conical puncture and the sheath due to external factors is avoided. Preventing water vapor from penetrating into the gap. When moisture or humidity enters longitudinally along the cable gap, the water blocking powder absorbs and expands, and further diffusion of the moisture is prevented.

The wrapping position of the high temperature resistant water-blocking tape 90 is preferably adjacent to a 30mm through hole of the protection box 30 for the trunk cable 10 and the branch cable 20 to pass through.

Example four

The fourth embodiment provides a flexible mineral insulation pre-branch fireproof cable, which has the same structure and principle as those of the third embodiment, except that the third embodiment provides a preferred structure of the connection part of the trunk cable 10 and the branch cable 20.

Before the protective box 30 is filled with the injection-molded cured product 70, a coating cushion layer is arranged on the exposed part of the cable body at the joint of the trunk cable 10 and the branch cable 20; the coating cushion layer is formed by sequentially wrapping a mica tape, a high-voltage insulating tape, a waterproof tape and a protective tape on two sides of the exposed part of the cable body.

When the insulation of the branch connection part is processed, firstly, the exposed part is wound with a double-sided synthetic mica tape in a manual mode, in order to ensure the fire resistance of the cable, the winding of the mica tape is not less than two layers, and at least more than 50% of the covering is carried out. The fire-resistant mica tape adopted in the wrapping is preferably double-sided synthetic mica tape with good fire resistance, can resist the temperature of more than 1000 ℃ and is close to the melting point of copper.

And then sequentially lapping by using a high-voltage insulating tape, a waterproof tape and a protective tape, and finally, completely coating the cushion layer on all the trunk and branch cable insulating wire cores. The insulating waterproof and flame retardant performance of the branch connecting part is ensured.

EXAMPLE five

The fifth embodiment provides a flexible mineral insulation pre-branch fireproof cable, which has the same structure and principle as those of the fourth embodiment, except that the present application provides a preferred structural design of the trunk cable 10 and the branch cables 20 based on the fifth embodiment.

The main cable 10 comprises 4 stranded cable cores, an inorganic filling layer, a high-strength protective layer, a copper sheath, a high-temperature-resistant heat insulation layer and an outer sheath which are sequentially arranged from inside to outside. Each cable of the main cable 10 comprises a conductor, a mineral insulating fire-resistant layer and an insulating layer which are arranged from inside to outside in sequence.

The conductor is a non-metal-plated layer stranded copper conductor which conforms to a class 2 compact circular structure specified in GB/T3956-2008 conductor of cable. In the design process, the pitch of the stranded wire is precisely controlled, and the good conductivity of the product is ensured. In the production process, an online continuous monitoring technology is implemented on the working procedures of wire drawing, annealing and stranding, so that the defect-free copper single wire is ensured.

Wherein, the mineral insulating fire-resistant layer arranged outside the conductor adopts a mica tape for fire-resistant safety cables which conforms to the GB/T5019 regulation. The temperature-resistant grade is enhanced while the electrical performance of the cable is ensured. The mineral mica tape is prepared by adopting high-temperature-resistant materials such as mica paper, glass cloth and the like through the processes of compounding, drying and the like, and the mica tape is lapped outside the conductor in an overlapping mode by taking 25% of the bandwidth as a covering rate, so that the capability of bearing continuous high temperature of the conductor is ensured. The insulating layer is made of ceramic mineral insulating material and adopts a continuous extrusion process. Under the condition that the insulating layer is heated to a temperature of more than 500 ℃, a compact and hard ceramic armor body can be rapidly generated, and on one hand, the internal structure is sealed. The internal refractory layer is ensured to be compact and not to fall off; on the other hand, the heat insulation capability can be improved, and the shock resistance is certain.

The inorganic filling layer is densely filled with inorganic filling ropes, and has heat insulation and temperature resistance. The inorganic filling rope is formed by twisting an alkali-free glass fiber filling rope and an asbestos rope according to a certain proportion, and the alkali-free glass fiber filling rope and the asbestos rope are uniformly and tightly distributed in gaps among the conductors.

The high-strength protective layer is composed of a reinforced alkali-free glass fiber band subjected to infiltration treatment, and the material components are inorganic matters and can bear flame impact. The breaking strength of the alkali-free glass fiber tape is more than or equal to 875N/25mm, the requirement of JC/T174-2005 alkali-free glass fiber tape on the breaking strength is met, and the cable core structure can be effectively protected.

Wherein, the high temperature resistant heat insulation layer consists of an alkali-free glass fiber band and a high flame-retardant band. The material component is inorganic matter, and has better high temperature resistance.

The outer sheath may have a larger thickness so that the tapered piercing of the first reinforcing cable clamp 50 can pierce through the outer sheath and be clamped on the outer sheath. The outer sheath can adopt the conventional outer sheath of the flexible mineral insulated cable in the field, and also can preferably adopt polyetheretherketone, and the manufactured outer sheath has the following advantages: 1. the temperature resistant grade is 260 ℃, and the hydrolysis resistance is excellent; can be continuously used in high-temperature, high-pressure steam or water environment. And the manufactured cable is halogen-free, low-smoke, flame-retardant, non-toxic and environment-friendly. 2. Excellent chemical resistance and excellent irradiation resistance; the corrosion resistance is similar to that of nickel steel, and the insulating property can be kept well under high irradiation. 3. The fatigue resistance to alternating stress is comparable to that of alloy materials. Also has certain self-lubricating property and abrasion resistance; greatly reducing the abrasion, damage and the like of the cable in the dragging operation process.

A person skilled in the art may apply a pressing process to the first reinforcing cable clamp 50 by means of hydraulic pliers to clamp the first reinforcing cable clamp 50 to the main cable 10. If desired, the tapered piercing end of the first reinforcing cable clamp 50 may be pierced and snapped onto the copper sheath.

The branch cable 20 comprises a stranded cable core, inorganic fiber filler, a copper sheath and an outer sheath which are sequentially arranged from inside to outside; each cable of the feeder cable 20 comprises a conductor and an inorganic insulating wrapping tape which are arranged from inside to outside in sequence.

The outer sheath may have a larger thickness so that the tapered piercing of the second reinforcing cable clamp 60 may pierce the outer sheath and be clamped thereto. The outer sheath can adopt the conventional outer sheath of the flexible mineral insulated cable in the field, and also can preferably adopt polyetheretherketone, and the manufactured outer sheath has the following advantages: 1. the temperature resistant grade is 260 ℃, and the hydrolysis resistance is excellent; can be continuously used in high-temperature, high-pressure steam or water environment. And the manufactured cable is halogen-free, low-smoke, flame-retardant, non-toxic and environment-friendly. 2. Excellent chemical resistance and excellent irradiation resistance; the corrosion resistance is similar to that of nickel steel, and the insulating property can be kept well under high irradiation. 3. The fatigue resistance to alternating stress is comparable to that of alloy materials. Also has certain self-lubricating property and abrasion resistance; greatly reducing the abrasion, damage and the like of the cable in the dragging operation process.

A person skilled in the art may apply a pressing process to the second reinforcing cable clamp 60 by means of hydraulic pliers so as to clamp the second reinforcing cable clamp 60 to the main cable 10. If desired, the tapered piercing end of the second reinforcing cable clamp 60 may be pierced and snapped onto the copper sheath.

Preparation method

The utility model also provides a preparation method of the flexible mineral substance insulation pre-branch fireproof cable, which is used for manufacturing the flexible mineral substance insulation pre-branch fireproof cable in the first to fifth embodiments. Specifically, the preparation method of the flexible mineral insulation pre-branching fireproof cable comprises the following steps:

(1) stripping an inorganic filling layer, a high-strength protective layer, a copper sheath, a high-temperature-resistant heat-insulating layer and an outer sheath from the middle section of the main cable by adopting a cable stripper; and the mineral insulating fire-resistant layer and the insulating layer are used for obtaining a cut part, and removing sundries in the cut part to expose the cable core. Wherein the total length of the cut portion is not preferably more than 20 cm.

(2) Winding the connecting wire core of the branch cable on the conductor of the cut part of the trunk cable, using a C-shaped jacket at the connecting part of the trunk cable and the branch cable, and adopting hydraulic pliers to carry out pressing treatment.

(3) And aligning the lower box body of the protection box with the connection part of the trunk cable and the branch cable, and estimating the mounting positions of the first reinforcing cable clamp and the second reinforcing cable clamp. And respectively sleeving the first reinforcing cable clamp and the second reinforcing cable clamp at corresponding positions of the trunk cable and the branch cable, and adopting hydraulic pliers to perform compression treatment.

(4) And sequentially wrapping the exposed part of the cable body at the joint of the trunk cable and the branch cable with a double-faced synthetic mica tape, a high-voltage insulating tape, a waterproof tape and a protective tape.

(5) And assembling the protection box, so that the cut part of the main cable, the cable body adjacent to the cut part, the connecting wire core of the branch cable and the cable body adjacent to the connecting wire core are all arranged in the protection box.

(6) And adopting injection molding equipment to perform injection molding filling on the halogen-free flame-retardant polyolefin material through the injection molding hole of the protection box, so that the injection molding filling body is completely filled in the gap between the protection box and the trunk cable and the gap between the protection box and the branch cable.

Test method

Test one: testing tensile strength of branch connecting part of flexible mineral substance insulation pre-branch fireproof cable

Comparative example 1: the raw materials, the cable structure and the preparation process adopted in the comparative example 1 are all the same as those of the fifth example. Except that the feeder cable of comparative example 1 did not contain a second reinforcing cable clamp.

In the process of carrying out tear resistance detection on the cable, a clamp is used for fixing a branch connecting part of the flexible mineral substance insulation branch fireproof cable, branch cables of the test sample are cut to be uniform in length, a tensile testing machine is used for pulling the branch cables, the branch cables of the test sample are pulled to be broken, and the maximum force value (unit: N) is recorded.

TABLE 2 maximum force values for pre-branch cable specimens pulled to break

Sample (I)	EXAMPLE five	Comparative example 1
			Maximum force value N	153.1	107.3

And (2) test II: performance test for testing branch connecting part of flexible mineral substance insulation pre-branch fireproof cable

Based on part of technical requirements of JB/T10636-; the test structure is shown in table 3.

TABLE 3 Pre-Branch fireproof Cable Performance test

Other structures of the flexible mineral insulation pre-branch fireproof cable described in the embodiment are shown in the prior art.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, so that any modification, equivalent change and modification made to the above embodiment according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A flexible mineral insulated pre-branch fireproof cable, comprising:

2. The flexible mineral insulated pre-branch fireproof cable of claim 1, wherein:

the cross-sectional shapes of the first reinforcing cable clamp and the second reinforcing cable clamp are both C-shaped, a plurality of conical punctures are arranged on the inner surfaces of the first reinforcing cable clamp and the second reinforcing cable clamp, and the conical punctures are used for puncturing sheaths of cables.

3. The flexible mineral insulated pre-branch fireproof cable of claim 2, wherein:

the second reinforcing cable clamp comprises a C-shaped main body and a plurality of conical punctures arranged on the inner surface of the C-shaped main body;

4. A flexible mineral insulated pre-branch fireproof cable according to claim 3, wherein:

the outer surface of the C-shaped main body is provided with a plurality of semi-annular cutting grooves which are sequentially arranged at equal intervals along the axis of the C-shaped main body; the outer surface of the C-shaped main body is uneven due to the semi-annular grooves, so that the C-shaped main body and the injection-molded condensate form a chimeric structure.

5. The flexible mineral insulated pre-branch fireproof cable of claim 2, wherein:

a high-temperature-resistant water-blocking tape is arranged between the inner surface of the first reinforcing cable clamp and the outer surface of the main cable, and before the first reinforcing cable clamp is connected with the cable body of the main cable, the high-temperature-resistant water-blocking tape is wound on the cable body corresponding to the main cable;

6. The flexible mineral insulated pre-branch fireproof cable of claim 1, wherein:

before filling the injection-molded cured substance in the protection box, arranging a coating cushion layer on the exposed part of the cable body at the joint of the trunk cable and the branch cable; the coating cushion layer is formed by sequentially wrapping a mica tape, a high-voltage insulating tape, a waterproof tape and a protective tape on two sides of the exposed part of the cable body.

7. The flexible mineral insulated pre-branch fireproof cable of claim 1, wherein:

the injection molding condensate is formed by injection molding and filling of a low-smoke halogen-free flame-retardant polyolefin material.

8. The flexible mineral insulated pre-branch fireproof cable of claim 1, wherein:

the main cable comprises a stranded cable core, an inorganic filling layer, a high-strength protective layer, a copper sheath, a high-temperature-resistant heat-insulating layer and an outer sheath which are sequentially arranged from inside to outside;

9. The flexible mineral insulated pre-branch fireproof cable of claim 1, wherein:

the branch cable comprises a stranded cable core, inorganic fiber filler, a copper sheath and an outer sheath which are sequentially arranged from inside to outside;