Flame-resistant cable and preparation method thereof

Abstract

The invention provides a flame-resistant cable and a preparation method, and relates to the technical field of cables. The cable comprises an inner layer, a middle layer arranged on the outer side of the inner layer and a plurality of fire-retardant rings arranged on the inner layer, a communication line is connected with the fire-retardant rings, fusing electric wires are arranged on the fire-retardant rings, the fire-retardant layer is filled in a cylindrical area between the adjacent fire-retardant rings, an outer layer is arranged on the outer side of the middle layer, the fusing electric wires are arranged in a U shape, and the rotation position of the fusing electric wires passes through the fire-retardant rings on the side portion. A communication module and a detection circuit for detecting whether the fusing electric wire is fused or not are arranged in the fire-retardant ring, the communication line is electrically connected with the fire alarm system, the fire-retardant layer comprises a heat-insulating filler, and a plurality of fire-retardant capsules are arranged in the heat-insulating filler. The preparation method comprises the following steps: preparing the inner layer, clamping the fire-retardant ring, and then preparing the middle layer and the outer layer in sequence. According to the invention, the alarm of the fire alarm system is automatically triggered when a fire occurs on the cable, so that fire fighters can quickly find the fire position to quickly fight the fire, and serious consequences caused by fire spreading are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a flame-resistant cable and a preparation method thereof. Background Art

[0002] A cable is made of one or more insulated conductors and an outer insulating protective layer. It is a wire that transmits electricity or information from one place to another.

[0003] At present, ordinary cables have poor flame retardancy and are easy to burn when exposed to fire. For some flame resistant cables, although their flame retardancy is increased, once the cables burn, the fire is still easy to spread. The most important thing is that cable fires are often not discovered in the first time, especially cables often shuttle through some confined spaces or corners. Generally, they have to wait until the cables are burned and power or communication abnormalities occur before inspection. At this time, the interval from the fire is long, and serious consequences often occur. Summary of the invention

[0004] The purpose of the present invention is to develop a flame-resistant cable and a preparation method thereof which automatically triggers the alarm of a fire alarm system when a cable fire occurs, so that firefighters can quickly find the fire location for rapid fire fighting and avoid the spread of fire and serious consequences.

[0005] The present invention is achieved through the following technical solutions: A flame resistant cable, comprising: Inner layer, the conductor is arranged in the inner layer; The middle layer is located outside the inner layer and includes: A plurality of fire-blocking rings are arranged on the inner layer; Communication lines, connected with multiple fire-blocking rings; The fuse is arranged on the fire-blocking ring; The fire barrier layer is filled in the cylindrical area between adjacent fire barrier rings; The outer layer is located outside the middle layer; The fusible wire is arranged in a U shape and passes through a fire-blocking ring on the side at the turning point. A communication module and a detection circuit for detecting whether the fusible wire is blown are arranged in the fire-blocking ring. The communication module is electrically connected to the detection circuit and the communication line. The fusible wire is electrically connected to the detection circuit. The communication line is electrically connected to the fire alarm system. The fire-blocking layer comprises a heat-insulating filler, and a plurality of fire-blocking capsules are arranged in the heat-insulating filler.

[0006] Optionally, the fire-blocking ring is in a circular ring shape and is coaxially arranged with the cable, a plurality of the fire-blocking rings are arranged at equal intervals in the length direction of the cable, and the inner edge and the outer edge of the fire-blocking ring are covered with a plurality of serrations.

[0007] Optionally, the communication line is externally sheathed with a rigid protective shell connected to a fire-blocking ring, and the communication line is arranged close to a fuse.

[0008] Optionally, the heat-insulating filler includes a mixed granular filler and a powdered filler, and the powdered filler is filled in the gaps of the granular filler; The granular filler is expanded perlite or ceramic microbeads, and the powdery filler is quartz sand or alumina powder.

[0009] Optionally, the fire-retardant capsule includes any one or more of a first capsule, a second capsule, and a third capsule, wherein the first capsule, the second capsule, and the third capsule all include an external sealing layer, wherein the sealing layer is a low-melting-point polymer, the sealing layer of the first capsule is filled with sodium silicate and a foaming agent, the sealing layer of the second capsule is filled with water or perfluorohexanone, and the sealing layer of the third capsule is filled with sodium bicarbonate and an acidic trigger.

[0010] Optionally, the outer layer includes an outer sheath, which is the outermost layer of the cable, a heat-conducting layer is arranged inside the outer sheath, a steel belt is arranged inside the heat-conducting layer, and a wrapping layer is arranged inside the steel belt.

[0011] Optionally, the outer sheath is low-smoke halogen-free polyolefin, the heat-conducting layer is an aluminum alloy mesh, silicon carbide nanowires are adhered to the aluminum alloy mesh, and the wrapping layer is thermoplastic polyurethane.

[0012] A method for preparing a flame resistant cable comprises the following steps: S1. Preparation of cable inner layer; S2. Connect multiple fire-blocking rings to the outer periphery of the inner layer of the cable in sequence; S3. The cable passes through the injection barrel, and the cable rotates at a constant speed while being axially transported in the injection barrel; S4. Fill the fire-blocking rings with heat-insulating fillers and fire-blocking capsules to form an intermediate layer; S5. The injection barrel injects the thermoplastic outer layer into the middle layer, and the outer layer is solidified by cooling; The injection barrel comprises a first pipe section, a second pipe section and a third pipe section which are coaxially connected. The first pipe section is filled with heat insulating fillers and fire retardant capsules, the second pipe section is filled with an outer layer, and the third pipe section cools the outer layer.

[0013] Optionally, a plurality of first injection ports are provided at equal intervals on the top of the first pipe section; The second pipe section includes an extrusion section and a shaping section. The cross section of the extrusion section is arched. The extrusion section is connected to the first pipe section. The extrusion section is first expanded, then straightened, and finally contracted. A second injection port is provided above the expanded portion of the extrusion section. The shaping section is cylindrical. The interior of the third pipe section is truncated cone-shaped, and its inner diameter gradually increases in the direction away from the second pipe section. A liquid injection pipe is provided at the top of the third pipe section near the second pipe section, and the liquid injection pipe is injected with coolant.

[0014] Optionally, in step S2, the inner diameter of the inner edge of the fireblocking ring is smaller than the outer diameter of the inner layer, a notch is provided on the fireblocking ring, the fireblocking ring at the notch is a thermoplastic polymer, the fireblocking ring is arc-shaped before being enclosed to the outside of the inner layer, and when the fireblocking ring is clamped on the outer layer, the inner layer of the cable is on the inner side of the fireblocking ring, the notch is heated by an electric heating device, and then the fireblocking ring is enclosed on the inner layer of the cable, the serrations on the inner edge of the fireblocking ring are embedded in the surface of the inner layer, the two sides of the notch of the fireblocking ring are in close contact to achieve encirclement, and then the hot joint of the notch is quickly cooled and solidified, so that the fireblocking ring is clamped on the inner layer.

[0015] The beneficial effects of the present invention are: When the local temperature of the cable rises abnormally, the heat conductive layer can conduct the heat to both sides as much as possible to disperse the heat, thus avoiding fire in the cable or prolonging the time required for the cable to burn; When the cable inevitably burns due to external fire sources, the fuse will melt due to heat, triggering the alarm of the fire alarm system. According to the position of the communication module configured by the fuse, the firefighters can quickly find the fire location so as to quickly put out the fire and avoid the spread of fire and serious consequences. In addition, the fire alarm system can be configured with multiple positions of sprinkler heads corresponding to the communication modules. When the alarm of the fire alarm system is triggered, the fire alarm system controls the sprinkler heads at the corresponding positions to directly spray and extinguish the fire, thereby minimizing the loss. When a fire occurs, the fire barrier layer can prevent the fire from spreading to the internal conductor of the cable or directly extinguish the fire. After the fire barrier capsules are melted and ruptured by high temperature, some fire barrier capsules form foaming structures to isolate oxygen, some fire barrier capsules have internal liquid immersed in the thermal insulation filler, and some fire barrier capsules quickly produce carbon dioxide gas, which is immersed in the thermal insulation filler. The gap of the thermal insulation filler is very small, and the liquid entering the gap evaporates and absorbs heat to cool down. The carbon dioxide fills the thermal insulation filler to avoid combustion in the thermal insulation filler, thereby delaying or extinguishing the fire. The set fire barrier ring can also slow down the spread of fire in the axial direction of the cable to a certain extent, further reducing the losses caused by the fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The layered structure diagram of the cable; Figure 2 This is the connection structure diagram of the fire-blocking ring, the communication line and the fuse; Figure 3 This is the structural diagram of the injection barrel.

[0018] Figure numerals: 1. inner sheath; 2. fire-blocking ring; 3. communication line; 4. fuse; 5. wrapping layer; 6. steel belt; 7. heat-conducting layer; 8. outer sheath; 9. first pipe section; 10. second pipe section; 11. third pipe section; 12. first injection port; 13. second injection port; 14. liquid injection pipe. DETAILED DESCRIPTION

[0019] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0022] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the present invention discloses a flame-resistant cable, comprising an inner layer, a middle layer and an outer layer, wherein the conductor is arranged in the inner layer, and the middle layer and the outer layer are both fire-resistant structures.

[0024] The inner layer includes an inner sheath 1, a fire-resistant mica tape is arranged outside the inner sheath 1, a boron nitride coating is coated on the conductor, an insulating layer is arranged outside the conductor, a conductor shielding layer is arranged between the conductor and the insulating layer, an insulating shielding layer is arranged outside the insulating layer, and a filler is arranged between the insulating shielding layer and the inner sheath 1.

[0025] The middle layer includes a plurality of fire-blocking rings 2 arranged at equal intervals in the length direction of the cable. The fire-blocking rings 2 are in the shape of a ring and are coaxially arranged with the cable. The inner wall of the fire-blocking ring 2 is connected to the inner sheath 1. The inner and outer edges of the fire-blocking ring 2 are covered with a plurality of saw teeth, which are embedded in the inner layer at the inner edge and the outer layer at the outer edge, so that the structure is stable in the cable and will not be displaced.

[0026] The middle layer also includes two communication lines 3 connected to multiple fireblocking rings 2. The two communication lines 3 are located in the same radial direction of the fireblocking rings 2 and are symmetrical. The communication lines 3 are externally sheathed with a protective shell connected to the fireblocking rings 2. The protective shell is a rigid structure that keeps the multiple fireblocking rings 2 fixed.

[0027] like Figure 2 As shown, four groups of fuses 4 are provided on the fire barrier ring 2, and the two communication lines 3 are arranged close to the fuses 4. Even if there is fire or high temperature at the communication line 3, there is a protective shell outside the communication line 3, so that the fuse 4 melts or breaks before the communication line 3. A communication module and a detection circuit for detecting whether the fuse 4 is melted are provided in the fire barrier ring 2. The communication module is electrically connected to the detection circuit and the communication line 3. The communication module has a built-in unique address or position code, and the communication line 3 is electrically connected to the fire alarm system.

[0028] When a certain fuse 4 is melted or broken, the communication module electrically connected to the fuse 4 transmits an electrical signal to the fire alarm system through the communication line 3, triggering the fire alarm. The approximate location of the cable fire can be directly shown according to the address or position code of the communication module, so that the firefighters can quickly find the fire point to put out the fire and prevent the fire from spreading further. If the site conditions permit, a sprinkler head and other fire extinguishing components can be set on the side of the cable laying track. The position of the sprinkler head is installed corresponding to the position of the communication module. When the fuse 4 on the communication module is melted, the fire alarm system receives a signal and controls the sprinkler head on the side of the communication module to work to extinguish the fire, further quickly controlling the fire.

[0029] The fusible wire 4 is arranged in a U shape, and the fusible wire 4 includes a first straight section, a turn section and a second straight section. The first straight section extends from the fireblocking ring 2 into the fireblocking ring 2 adjacent to the fireblocking ring 2, the turn section is in the adjacent fireblocking ring 2, and the second straight section extends from the adjacent fireblocking ring 2 and returns to the fireblocking ring 2. The first straight section and the second straight section are both arranged parallel to the axial direction of the cable.

[0030] The cylindrical area between adjacent fire-blocking rings 2 is filled with a fire-blocking layer, which includes a heat-insulating filler, and a plurality of fire-blocking capsules are arranged in the heat-insulating filler.

[0031] The heat insulating filler includes a mixed granular filler and a powder filler, and the powder filler is filled in the gaps of the granular filler to make the heat insulating filler as compact as possible and reduce the porosity. The granular filler can be expanded perlite or ceramic micro beads, and the powder filler can be quartz sand or alumina powder.

[0032] The fire-blocking capsule includes any one or more of the first capsule, the second capsule, and the third capsule. The first capsule, the second capsule, and the third capsule all include an external sealing layer, which is a low-melting-point polymer, such as polyethylene. The sealing layer melts and breaks when the cable burns or the temperature is high.

[0033] The sealing layer of the first capsule is filled with sodium silicate and a foaming agent. The sodium silicate is hydrated sodium silicate and the foaming agent is sodium bicarbonate or ammonium bicarbonate. When the cable burns or is at high temperature, the sodium silicate and the foaming agent react to form a foam structure to isolate oxygen.

[0034] The sealing layer of the second capsule is filled with water or perfluorohexanone, which absorbs heat when the cable burns or is at high temperature.

[0035] The sealing layer of the third capsule is filled with sodium bicarbonate and an acid trigger. The acid trigger can be any one of citric acid, tartaric acid, sodium bisulfate, and ammonium dihydrogen phosphate. When the cable is burning or at high temperature, the added acid trigger causes the sodium bicarbonate to react rapidly to produce a large amount of carbon dioxide, which is filled in the insulation filler to achieve the purpose of extinguishing the fire.

[0036] The outer layer includes an outer sheath 8, which is the outermost layer of the cable, a heat-conducting layer 7 is arranged inside the outer sheath 8, a steel belt 6 is arranged inside the heat-conducting layer 7, and a wrapping layer 5 is arranged inside the steel belt 6. The outer sheath 8 is low-smoke halogen-free polyolefin, the heat-conducting layer 7 is an aluminum alloy mesh, silicon carbide nanowires are adhered to the aluminum alloy mesh, and the wrapping layer 5 is thermoplastic polyurethane.

[0037] The present invention also discloses a method for preparing the flame-resistant cable, comprising the following steps: S1. Preparation of cable inner layer; S2. The plurality of fire-blocking rings 2 are sequentially clamped on the outer periphery of the inner layer of the cable; S3. The cable passes through the injection barrel, and the cable rotates at a constant speed while being axially transported in the injection barrel; S4. Fill the insulation filler and the fire-blocking capsule between the two fire-blocking rings with an injection barrel to form an intermediate layer; S5. The injection barrel injects the thermoplastic wrapping layer 5 into the intermediate layer, and the wrapping layer 5 is solidified by cooling; S6. Coating the steel strip 6 on the wrapping layer 5; S7. Wrapping or coating the heat conductive layer 7 on the steel strip 6; S8. Injecting a thermoplastic outer sheath 8 into the heat conductive layer 7, and solidifying the outer sheath 8 by cooling; Among them, the inner layer structure of the cable is existing technology and will not be described in detail here.

[0038] In step S2, the inner diameter of the inner edge of the fireblocking ring 2 is smaller than the outer diameter of the inner layer, a notch is provided on the fireblocking ring 2, the internal line of the fireblocking ring 2 does not pass through the notch, and the fuse 4 and the communication line 3 are at a certain distance from the notch, the fireblocking ring 2 at the notch is a thermoplastic polymer, and the fireblocking ring 2 is arc-shaped before being enclosed to the outside of the inner layer. When the fireblocking ring 2 is clamped, the inner layer of the cable is on the inner side of the fireblocking ring 2, and the notch is heated by an electric heating device, and then the fireblocking ring 2 is enclosed on the inner layer of the cable, and the serrations on the inner edge of the fireblocking ring 2 are embedded in the surface of the inner layer to a certain depth, and the two sides of the notch of the fireblocking ring 2 are in close contact to achieve encirclement, and then air cooling is performed to quickly cool and solidify the hot joint of the notch, so that the fireblocking ring 2 is clamped on the inner layer, and during the clamping process of the fireblocking ring 2, the protective shell of the communication line 3 is kept straight and parallel to the axial direction of the cable.

[0039] In steps S3 to S5, the structure of the injection barrel is as follows: Figure 3 As shown, it comprises a first pipe section 9, a second pipe section 10 and a third pipe section 11 which are coaxially connected, a heat insulating filler and a fire-blocking capsule are injected into the first pipe section 9, a wrapping layer 5 is injected into the second pipe section 10, and the wrapping layer 5 is cooled in the third pipe section 11; The inner diameter of the first pipe section 9 is adapted to the outer diameter of the fire-blocking ring 2. Three first injection ports 12 are arranged at equal intervals on the first pipe section 9. The first injection ports 12 deliver heat-insulating fillers and fire-blocking capsules to the fire-blocking rings 2 of the cables in the first pipe section 9. The second pipe section 10 includes an extrusion section and a shaping section. The cross section of the extrusion section is arched. The extrusion section is connected to the first pipe section 9. The extrusion section is expanded first, then straightened, and finally contracted. The cross section at the expanded part is an arc surface and the inner diameter gradually expands. The straight part is cylindrical. The cross section at the contracted part is an arc surface and the inner diameter gradually decreases. The contracted part is connected to the shaping section. The shaping section is cylindrical and the inner diameter is adapted to the outer diameter of the wrapping layer 5. A second injection port 13 is provided above the expanded part of the extrusion section. The material of the extruder is injected through the second injection port 13 to realize the extrusion molding of the wrapping layer 5. The third pipe section 11 is truncated cone-shaped inside, and its inner diameter gradually increases in the direction away from the second pipe section 10. A liquid injection pipe 14 is provided at the top of the third pipe section 11 near the second pipe section 10, and the liquid injection pipe 14 is injected with coolant.

[0040] The above embodiments are only preferred embodiments of the present invention and are not limitations of the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A flame resistant cable, characterized in that: include: Inner layer, the conductor is arranged in the inner layer; The middle layer is located outside the inner layer and includes: A plurality of fire-blocking rings are arranged on the inner layer; Communication lines, connected with multiple fire-blocking rings; The fuse is arranged on the fire-blocking ring; The fire barrier layer is filled in the cylindrical area between adjacent fire barrier rings; The outer layer is located outside the middle layer; The fusible wire is arranged in a U shape and passes through a fire-blocking ring on the side at the turning point. A communication module and a detection circuit for detecting whether the fusible wire is blown are arranged in the fire-blocking ring. The communication module is electrically connected to the detection circuit and the communication line. The fusible wire is electrically connected to the detection circuit. The communication line is electrically connected to the fire alarm system. The fire-blocking layer comprises a heat-insulating filler, and a plurality of fire-blocking capsules are arranged in the heat-insulating filler.

2. The flame resistant cable according to claim 1, characterized in that: The fire-blocking ring is in a circular ring shape and is coaxially arranged with the cable. A plurality of the fire-blocking rings are arranged at equal intervals in the length direction of the cable, and the inner edge and the outer edge of the fire-blocking ring are covered with a plurality of saw teeth.

3. The flame resistant cable according to claim 1, characterized in that: The communication line is externally sheathed with a rigid protective shell connected to a fire-blocking ring, and the communication line is arranged close to the fuse.

4. The flame resistant cable according to claim 1, characterized in that: The heat-insulating filler comprises a mixed granular filler and a powdery filler, wherein the powdery filler is filled in the gaps of the granular filler; The granular filler is expanded perlite or ceramic microbeads, and the powdery filler is quartz sand or alumina powder.

5. The flame resistant cable according to claim 1, characterized in that: The fire-blocking capsule includes any one or more of a first capsule, a second capsule, and a third capsule. The first capsule, the second capsule, and the third capsule all include an external sealing layer, the sealing layer is a low-melting-point polymer, the sealing layer of the first capsule is filled with sodium silicate and a foaming agent, the sealing layer of the second capsule is filled with water or perfluorohexanone, and the sealing layer of the third capsule is filled with sodium bicarbonate and an acidic trigger.

6. The flame resistant cable according to claim 1, characterized in that: The outer layer comprises an outer sheath, which is the outermost layer of the cable, a heat conducting layer is arranged inside the outer sheath, a steel belt is arranged inside the heat conducting layer, and a wrapping layer is arranged inside the steel belt.

7. The flame resistant cable according to claim 6, characterized in that: The outer sheath is low-smoke halogen-free polyolefin, the heat-conducting layer is an aluminum alloy mesh, silicon carbide nanowires are adhered to the aluminum alloy mesh, and the wrapping layer is thermoplastic polyurethane.

8. A method for preparing a flame-resistant cable according to any one of claims 1 to 7, characterized in that: The steps include: S1. Preparation of cable inner layer; S2. Connect multiple fire-blocking rings to the outer periphery of the inner layer of the cable in sequence; S3. The cable passes through the injection barrel, and the cable rotates at a constant speed while being axially transported in the injection barrel; S4. Fill the fire-blocking rings with heat-insulating fillers and fire-blocking capsules to form an intermediate layer; S5. The injection barrel injects the thermoplastic outer layer into the middle layer, and the outer layer is solidified by cooling; The injection barrel comprises a first pipe section, a second pipe section and a third pipe section which are coaxially connected. The first pipe section is filled with heat insulating fillers and fire retardant capsules, the second pipe section is filled with an outer layer, and the third pipe section cools the outer layer.

9. The method for preparing a flame resistant cable according to claim 8, characterized in that: The top of the first pipe section is provided with a plurality of first injection ports at equal intervals; The second pipe section includes an extrusion section and a shaping section. The cross section of the extrusion section is arched. The extrusion section is connected to the first pipe section. The extrusion section is first expanded, then straightened, and finally contracted. A second injection port is provided above the expanded portion of the extrusion section. The shaping section is cylindrical. The interior of the third pipe section is truncated cone-shaped, and its inner diameter gradually increases in the direction away from the second pipe section. A liquid injection pipe is provided at the top of the third pipe section near the second pipe section, and the liquid injection pipe is injected with coolant.

10. The method for preparing a flame resistant cable according to claim 8, characterized in that: In the step S2, the inner diameter of the inner edge of the fireblocking ring is smaller than the outer diameter of the inner layer, a notch is provided on the fireblocking ring, the fireblocking ring at the notch is a thermoplastic polymer, the fireblocking ring is arc-shaped before being enclosed to the outside of the inner layer, and when the fireblocking ring is clamped on the outer layer, the inner layer of the cable is on the inner side of the fireblocking ring, the notch is heated by an electric heating device, and then the fireblocking ring is enclosed on the inner layer of the cable, the serrations on the inner edge of the fireblocking ring are embedded in the surface of the inner layer, the two sides of the notch of the fireblocking ring are in close contact to achieve encirclement, and then the hot joint of the notch is quickly cooled and solidified, so that the fireblocking ring is clamped on the inner layer.

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