阅读说明：本技术 一种电力电缆及其制备方法 (Power cable and preparation method thereof ) 是由 任志飞 周诚凯 张曙光 毛丹 于 2021-07-16 设计创作，主要内容包括：本发明涉及电缆技术领域,尤其涉及一种电力电缆及其制备方法,其电力电缆包括：遇热膨胀条；围绕遇热膨胀条设置的多个缆芯；包覆在多个缆芯外侧的内绝缘护套,内绝缘护套上设置有贯穿的通气孔；包覆在内绝缘护套外侧的外绝缘护套；设置在内绝缘护套和外绝缘护套之间的多个吸水膨胀条；其中,多个吸水膨胀条向内挤压内绝缘护套,使相邻缆芯外侧的内绝缘护套与外绝缘护套之间形成通道,本发明提供的电力电缆电力传输好、结构精巧、具备良好的散热性以及防潮性,使用寿命长。(The invention relates to the technical field of cables, in particular to a power cable and a preparation method thereof, wherein the power cable comprises: expanding the strips upon heating; a plurality of cable cores disposed around the thermally expandable strip; the inner insulating sheath is coated outside the cable cores and is provided with a through air hole; an outer insulating sheath coated outside the inner insulating sheath; a plurality of water-absorbing expansion strips disposed between the inner insulating sheath and the outer insulating sheath; the power cable provided by the invention has the advantages of good power transmission, exquisite structure, good heat dissipation and moisture resistance and long service life.)

1. An electrical power cable, comprising:

expanding the strips upon heating;

a plurality of cable cores disposed around the thermally expandable strip;

the inner insulating sheaths are coated outside the cable cores and are provided with through air holes;

the outer insulating sheath is coated outside the inner insulating sheath;

a plurality of water-swellable strips disposed between the inner insulating sheath and the outer insulating sheath;

the water-absorbing expansion strips extrude the inner insulating sheath inwards to enable the inner insulating sheath and the outer insulating sheath which are adjacent to the outer side of the cable core to form a channel.

2. A power cable according to claim 1, characterized in that the cable core comprises a conductor and an insulating layer covering the outside of the conductor.

3. A power cable according to claim 2, characterized in that the insulating layer is provided with an elastic mesh layer on the outside.

4. A power cable according to claim 3, characterized in that the elastic mesh layer comprises a plurality of first ribs extending in the length direction of the conductor and second ribs of helical structure wound outside the insulating layer and connected to the first ribs.

5. A power cable according to claim 4, characterized in that the outer surface of the insulating layer is provided with a plurality of first grooves extending in the length direction of the conductor and second grooves having a helical structure, the first ribs being formed in the first grooves and the second ribs being formed in the second grooves.

6. A power cable according to claim 1, characterized in that the inner insulating sheath is provided with yarns adhered to its outer surface.

7. A power cable according to claim 1, characterized in that the water-swellable strip is circular in cross-section.

8. A power cable according to claim 1, characterized in that a water-blocking layer is further arranged between the inner and outer insulating sheaths.

9. A method of making a power cable, comprising:

s1: twisting and shaping the thermal expansion strip and the cable cores to obtain a preformed body;

s2: extruding and wrapping a layer of inner insulating sheath on the outer side of the preformed body;

s3: processing the inner insulating sheath to form a plurality of vent holes on the local surface of the inner insulating sheath;

s4: and (3) tightly pressing the water-absorbing expansion strip on the outer side of the inner insulating sheath to obtain a pressed body, and tightly pressing a layer of outer insulating sheath on the outer side of the pressed body.

10. A method for preparing a power cable according to claim 9, wherein the cable core forming step comprises:

drawing and advancing a conductor, and sequentially arranging a first process, a second process and a third process on a conductor advancing path; wherein the content of the first and second substances,

the first procedure is to coat an insulating layer on the outer side of the conductor by an extrusion process;

the second procedure comprises the steps of forming a first groove with the same length as the conductor by adopting a first roller with a fixed position arranged on the outer side of the insulating layer, and forming a spiral second groove by adopting a second roller which moves around the conductor in an annular manner;

and the third procedure comprises heating the raw material of the expansion material and injecting the unformed expansion material into the first groove and the second groove through an injection device, wherein the expansion material is conveyed forwards along with the conductor and is formed in the first groove and the second groove after being cooled.

Technical Field

The invention relates to the technical field of cables, in particular to a power cable and a preparation method thereof.

Background

The application of the cable is very wide, and the common cable is mainly applied to a power system, an information transmission system and the like, and the cable for power information comprises a local cable, a television cable, an optical cable and the like. In China, infrastructure construction is continuously invested, and the requirements of power cables are increasing day by day. Different areas have different performance requirements on the power cable, for example, in factories, ships or underground construction places, the cable is easy to corrode and age due to the humid environment, and potential safety hazards exist.

At present to the dampproofing mode of cable prevent mainly that the moisture in the environment from invading inside the cable through setting up the water blocking layer, nevertheless set up the thickness that the water blocking layer can increase the cable on the one hand for the thermal diffusivity is poor, and on the other hand is along with the long-term use of cable, and the water blocking layer very easily suffers from the destruction, thereby makes the effect variation that blocks water of cable, has reduced the life of cable.

In view of the above problems, the designer actively makes research and innovation based on the practical experience and professional knowledge that is abundant for many years in the engineering application of such products, so as to create a cable label pasting device, which is more practical.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: a power cable and a preparation method thereof are provided for improving the heat dissipation performance and the moisture resistance of the cable.

In order to achieve the purpose, the invention adopts the technical scheme that: an electrical power cable comprising:

expanding the strips upon heating;

a plurality of cable cores disposed around the thermally expandable strip;

the inner insulating sheaths are coated outside the cable cores and are provided with through air holes;

the outer insulating sheath is coated outside the inner insulating sheath;

a plurality of water-swellable strips disposed between the inner insulating sheath and the outer insulating sheath;

the water-absorbing expansion strips extrude the inner insulating sheath inwards to enable the inner insulating sheath and the outer insulating sheath which are adjacent to the outer side of the cable core to form a channel.

Further, the cable core comprises a conductor and an insulating layer coated on the outer side of the conductor.

Further, an elastic grid layer is arranged on the outer side of the insulating layer.

Furthermore, the elastic grid layer comprises a plurality of first ribs extending along the length direction of the conductor and second ribs of a spiral structure, and the second ribs are wound outside the insulating layer and connected with the first ribs.

Furthermore, a plurality of first grooves extending in the length direction of the conductor and second grooves of a spiral structure are formed in the outer surface of the insulating layer, the first ribs are formed in the first grooves, and the second ribs are formed in the second grooves.

Further, yarns are adhered to the outer side surface of the inner insulating sheath.

Further, the cross section of the water-absorbing expansion strip is circular.

Furthermore, a water-resistant layer is arranged between the inner insulating sheath and the outer insulating sheath.

A method of making a power cable comprising:

s1: twisting and shaping the thermal expansion strip and the cable cores to obtain a preformed body;

s2: extruding and wrapping a layer of inner insulating sheath on the outer side of the preformed body;

s3: processing the inner insulating sheath to form a plurality of vent holes on the local surface of the inner insulating sheath;

s4: and (3) tightly pressing the water-absorbing expansion strip on the outer side of the inner insulating sheath to obtain a pressed body, and tightly pressing a layer of outer insulating sheath on the outer side of the pressed body.

Further, the cable core forming step comprises:

drawing and advancing a conductor, and sequentially arranging a first process, a second process and a third process on a conductor advancing path; wherein the content of the first and second substances,

the first procedure is to coat an insulating layer on the outer side of the conductor by an extrusion process;

the second procedure comprises the steps of forming a first groove with the same length as the conductor by adopting a first roller with a fixed position arranged on the outer side of the insulating layer, and forming a spiral second groove by adopting a second roller which moves around the conductor in an annular manner;

and the third procedure comprises heating the raw material of the expansion material and injecting the unformed expansion material into the first groove and the second groove through an injection device, wherein the expansion material is conveyed forwards along with the conductor and is formed in the first groove and the second groove after being cooled.

The invention has the beneficial effects that: firstly, the thermal expansion strips are arranged in the power cable, when the temperature of the cable core rises, the thermal expansion strips push the surrounding cable core towards the periphery, so that the surfaces of a plurality of cable cores are not contacted any more, the phenomenon that the temperature of the contact part is gathered is avoided, and the heat dissipation is accelerated; secondly, arranging inner insulating sheaths outside the plurality of cable cores, and arranging vent holes on the inner insulating sheaths, wherein when the temperature of the cable cores is too high, the inner insulating sheaths are thermally deformed by the thermal expansion strips and push the surrounding cable cores open towards the periphery, and at the moment, the inner insulating sheaths wrapped outside the plurality of cable cores are also pushed open to further expand the opening degree of the vent holes, so that hot gas inside and outside the inner insulating sheaths is conducted, and uniform heat dissipation is facilitated; the moisture that enters into the inside cable can effectively be adsorbed through setting up the inflation strip that absorbs water, and the inflation strip that absorbs water adopts the inflation rubber material that absorbs water, after adsorbing a certain amount of moisture, the inflation strip that absorbs water can the volume expansion to plug up the air vent, avoid the moisture further to spread cable core department, played dampproofing effect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a power cable according to an embodiment of the present invention;

FIG. 2 is an enlarged view of the position A in the embodiment of the present invention;

fig. 3 is a cross-sectional view of a power cable in an embodiment of the present invention.

Reference numerals: 1. expanding the strips upon heating; 2. a conductor; 3. an insulating layer; 4. an inner insulating sheath; 5. a vent hole; 6. an outer insulating sheath; 7. a water-absorbing intumescent strip; 8. a first rib; 9. a second rib; 10. a water resistant layer.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Example one

As shown in fig. 1 to 3, the present embodiment provides a power cable including:

expanding the strip 1 when heated;

a plurality of cable cores arranged around the strip 1;

the inner insulating sheath 4 is coated on the outer sides of the cable cores, and the inner insulating sheath 4 is provided with a through air hole 5;

an outer insulating sheath 6 coated outside the inner insulating sheath 4;

a plurality of water-absorbing expansion strips 7 disposed between the inner insulating sheath 4 and the outer insulating sheath 6;

the inner insulating sheath 4 is extruded inwards by the water-absorbing expansion strips 7, so that a channel is formed between the inner insulating sheath 4 and the outer insulating sheath on the outer sides of the adjacent cable cores.

As shown in fig. 1 and 2, a thermal expansion strip 1 is arranged on a central axis of the cable, a plurality of insulated cable cores are arranged around the outer side of the thermal expansion strip 1, the cable cores are attached to the thermal expansion strip 1 in a twisting or co-extrusion manner, the thermal expansion strip 1 is made of a rubber material which can generate high deformation along with temperature change, when the temperature of the cable cores rises, the thermal expansion strip 1 pushes the surrounding cable cores towards the periphery, so that the surfaces of the plurality of cable cores are not contacted any more, the temperature of the contact part can be prevented from being gathered, the insulation layer of the cable core is damaged, after the thermal expansion strip 1 and the cable cores are twisted or co-extruded into the cable, an inner insulation sheath 4 is used for wrapping, the inner insulation sheath is made of an elastic material, a through vent hole 5 is arranged on the inner insulation sheath 4, the vent hole 5 is in a closed state under a normal state, and when the temperature of the cable cores is too high, the thermal expansion strip 1 is thermally deformed to push the surrounding cable cores open towards the periphery, at the moment, the inner insulating sheath 4 wrapped outside the plurality of cable cores is also expanded, the opening degree of the vent holes 5 is further expanded, so that the hot gas inside and outside the inner insulating sheath 4 is conducted, and uniform heat dissipation is facilitated, the outer insulating sheath 6 is also arranged outside the inner insulating sheath 4, the outer insulating sheath 6 is made of polyethylene or polyolefin and mainly plays a role in protecting the inner layer structure of the cable, and has the effects of ageing resistance and insulation, wherein a plurality of water-absorbing expansion strips 7 are arranged between the inner insulating sheath 4 and the outer insulating sheath 6, the plurality of water-absorbing expansion strips 7 are further cabled with the inner insulating layer 4 in a twisting or co-extrusion mode, and as can be seen from the figure, the water-absorbing expansion strips 7 are formed in the gap between two adjacent cable cores, so on the one hand, be favorable to the circularity of cable, on the other hand, can adsorb the moisture that enters into the cable inside through setting up water absorption expansion strip 7, then heat moisture through the heat release of conductor, make it volatilize outside, wherein radial moisture can enter into cable core inside roughly can divide into two kinds of condition, outer insulating sheath 6 of the skin of one kind takes place the breakage, under the other kind uses for a long time, outer insulating sheath 6 ages, thereby produce the crack on the surface, can effectively adsorb the moisture that enters into the cable inside through setting up water absorption expansion strip 7, water absorption expansion strip 7 adopts water absorption expansion rubber material, after adsorbing a certain amount of moisture, water absorption expansion strip 7 can the volume expansion, thereby block up air vent 5, avoid moisture further to spread to the cable core department, the dampproofing effect has been played, even the inner insulating sheath 4 of inside also equals outer insulating sheath 6 to take place the breakage, the water absorption expansion strip 7 can adsorb moisture in the inner insulating sheath 4 to the self due to the hydrophilic characteristic of the self, and the moisture-proof effect can be achieved. Generally, the cable provided by the invention has good moisture-proof effect and heat dissipation effect, and the overall heat dissipation performance of the cable can be adjusted according to the heat change through the arranged thermal expansion strip 1, so that the cable core is in a constant range, and the influence of overhigh or overlow temperature on the conductivity of the conductor is avoided.

More specifically, the cable core includes conductor 2 and the cladding insulating layer 3 in the conductor 2 outside, conductor 2 can adopt the copper conductor or the aluminum conductor of single core, also can adopt the copper conductor or the aluminum conductor of multicore transposition, as long as guarantee the circularity of periphery can, adopt copper conductor resistivity low, the electric conductivity is better, adopt aluminum conductor with low costs and lighter weight, select according to actual conditions can, insulating layer 3 adopts low smoke and zero halogen's polyolefin or polyethylene material, possess excellent insulating nature and ageing resistance, can use for a long time, and the service life of cable is prolonged.

Preferably, in the above embodiment, in order to make the heat dissipation of the conductor 2 more uniform and to protect the conductor 2 from impact, an elastic mesh layer is provided outside the insulating layer 3, and the elastic mesh layer is composed of a plurality of ribs.

According to the invention, the elastic grid layer is arranged between the conductor 2 and the insulating layer 3, the elastic grid layer is made of rubber which expands with low expansion coefficient when heated, the insulating layer 3 and the inner insulating sheath 4 are separated by the elastic grid layer, and heat emitted from the insulating layer 3 can be uniformly mixed in the grid, so that the heat generated by the conductor 2 can be uniformly dispersed towards the inner insulating sheath 4, the phenomenon of heat concentration is avoided, and due to the addition of the elastic grid layer, the impact resistance protection on the conductor 2 is further increased, and the extrusion deformation and impact damage of the conductor can be reduced by the deformation of the elastic grid layer.

As shown in fig. 1, for the convenience of processing, the elastic grid layer includes a plurality of first ribs 8 extending along the length direction of the conductor 2 and second ribs 9 having a spiral structure, and the second ribs 9 are wound outside the insulating layer 3 and connected to the first ribs 8.

In order to facilitate the processing and forming of the elastic grid layer, a plurality of first grooves extending along the length direction of the conductor and second grooves of a spiral structure are formed in the outer surface of the insulating layer 3, the first ribs 8 are formed in the first grooves, and the second ribs 9 are formed in the second grooves.

In order to be able to transmit the moisture in the cable to the water-absorbing expansion strip 7 quickly, the yarn is adhered to the surface of the outer side of the inner insulating sheath 4, the yarn has good water absorption, the yarn is attached to the water-absorbing expansion strip 7, the absorbed water can be permeated to the water-absorbing expansion strip 7, and the effect of blocking the moisture is further improved.

In the above embodiment, the water-swellable strips 7 are preferably made of a water-swellable rubber material and have a circular cross-section. The water-absorbing expansion strips 7 of circular structure are for the convenience of processing on the one hand, and on the other hand, do not interfere with the air vents 5 by themselves when not absorbing water.

In order to further enhance the waterproof effect of the cable, a water-blocking layer 10 is further arranged between the inner insulating sheath 4 and the outer insulating sheath 6, the thickness of the water-blocking layer 10 is smaller than that of the outer insulating sheath 6, and the water-blocking layer 10 is made of high-density polyethylene or polyolefin materials and is good in water-blocking effect.

Example two

The embodiment provides a preparation method of a power cable, which comprises the following steps:

s1: twisting and shaping the thermal expansion strip 1 and the cable cores to obtain a preformed body;

s2: extruding and coating a layer of inner insulating sheath 4 on the outer side of the preformed body;

s3: processing the inner insulating sheath 4 to form a plurality of vent holes on the local surface of the inner insulating sheath;

s4: and (3) pressing the water-absorbing expansion strip 7 on the outer side of the inner insulating sheath 4 to obtain a pressed body, and pressing a layer of outer insulating sheath 6 on the outer side of the pressed body.

Specifically, the strip 1 expanding when being heated and the cable cores are twisted and molded through a twisting machine to obtain a preformed body, an inner insulating sheath 4 is extruded on the outer side of the preformed body, then the surface of the inner insulating sheath 4, which is not in contact with the cable cores, is subjected to notch processing, a through air hole 5 is formed in the surface of the sheath of the inner insulating layer 3, then the water absorption expansion 7 is tightly pressed on the outer side of the inner insulating sheath 4 to obtain a pressing body, an outer insulating sheath 6 is extruded on the outer side of the pressing body, and after water cooling, the prepared cable is wound on a winding device to complete the whole processing process.

As a preference of the above embodiment, the cable core forming step includes:

drawing and advancing a conductor 2, and sequentially arranging a first process, a second process and a third process on a travelling path of the conductor 2; wherein the content of the first and second substances,

the first procedure is to coat an insulating layer 3 on the outer side of the conductor 2 by an extrusion process;

the second procedure comprises the steps of forming a first groove with the same length as the conductor 2 by adopting a first roller with a fixed position arranged outside the insulating layer 3, and forming a spiral second groove by adopting a second roller which moves around the conductor 2 in a ring shape;

the third step includes heating the raw material of the expandable material and injecting an unmolded expandable material into the first groove and the second groove by an injection device, the expandable material being conveyed forward along with the conductor 2 and being molded in the first groove and the second groove after cooling.

Specifically, the conductor 2 is pulled by a traction roller to advance, a first process, a second process and a third process are sequentially arranged on the advancing path of the conductor 2, wherein the first process is to coat a layer of insulating layer 3 on the outer side of the conductor 2 by arranging a rubber extruder, the insulating layer 3 is not completely formed when being extruded, at the moment, the second process is arranged to process a space for accommodating an elastic grid layer between the insulating layer 3 and the conductor 2, the second process comprises three first rollers which are fixed in position and can rotate per se, the first rollers are arranged by being attached to the outer surface of the insulating layer 3, when the insulating layer 3 is conveyed forwards, the first rollers roll and form a first groove with the same length as the conductor 2 on the outer surface of the insulating layer 3, and are arranged at equal intervals around the conductor 2 as a center circumference, and a second roller which can move annularly around the conductor 2 is also arranged, when the conductor 2 is conveyed forwards, a spiral second groove is formed on the outer surface of the insulating layer 3 in a rolling mode, a third process is introduced to inject raw materials of expansion materials into the first groove and the second groove, the raw materials of the expansion materials are heated into a gel shape through a heating device, uncooled expansion materials are injected into the first groove and the second groove through an injection device, the expansion materials are conveyed forwards along with the conductor 2 and are formed inside the first groove and the second groove after being cooled to form a net-shaped structure, a small amount of the gel expansion materials can flow to other positions on the outer surface of the insulating layer 3 in the injection process, the net-shaped structure is formed continuously after the forming, a finer gap space is formed, and heat can be transferred uniformly.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.