Halogen-free low-smoke fireproof cable

Abstract

In order to solve the problems of heat conduction, excessive ceramization, influence on the performance of a part which is not subjected to a fire disaster and increase of maintenance cost, an armored protection layer and a separation assembly are arranged at an interval, and the separation assembly is of a continuous broken-line-shaped tubular structure, so that the bending difficulty of the cable can be reduced, and the cable is suitable for being laid in a narrow and small space; the partition assembly comprises a folding cavity, an outer layer shell and an inner layer shell, a V-shaped groove is formed in the downward bending position of the outer layer shell, ceramization powder accounting for two thirds of the volume of the outer layer shell is contained in the V-shaped groove, the powder can enter the folding cavity after a plugging piece in a side circulation hole is heated and melted, and according to the design, ceramization reaction spreading is controlled through a sectional structure, thermal stress concentration is relieved, and the service life of the ceramic is prolonged. The heat insulation effect is enhanced, continuous work of the cable in a fire disaster is guaranteed, the problem of flexibility reduction caused by unnecessary ceramization is avoided, and construction flexibility and fire-resistant reliability are both considered.

Description

Technical Field

[0001] The present invention relates to the technical field of fire-resistant cables, and particularly to a halogen-free low-smoke fire-resistant cable. Background Art

[0002] Halogen-free low-smoke fire-resistant cables have become important power transmission carriers due to their high safety, good environmental protection, and strong reliability. Their fire-resistant performance can ensure power supply to the line during a fire. The low-smoke and halogen-free characteristics can reduce the generation of smoke and toxic gases during a fire, ensuring the safety of personnel's lives and reducing environmental and equipment damage. At the environmental protection level, their production and use are completely halogen-free and the materials are easily recyclable, meeting environmental protection requirements. In terms of electrical performance, they are stable, reliable, have good insulation, and also have good corrosion resistance, are suitable for various harsh environments, can extend the service life, and reduce maintenance costs.

[0003] In Chinese Patent 201822178454.4, this application relates to the technical field of power cables, specifically to a high-temperature fire-resistant cable for engine compartments and engines, including a shielding tape, a copper conductor, a fire-resistant layer, and a flame-retardant layer. A flame-retardant coating is filled between each two groups of limiting baffles. A dry-ice filling layer is filled inside the flame-retardant layer, and multiple groups of flame-retardant plates are fixedly connected to the inner wall of the flame-retardant layer. Multiple groups of flame-retardant sheaths are sleeved on the surface of the flame-retardant layer, and multiple groups of flame-retardant sheaths are fixedly connected inside the flame-retardant layer. The beneficial effects are as follows: Multiple groups of flame-retardant plates are arranged inside the flame-retardant layer, enabling the uniform overflow of dry ice, ensuring the flame-retardant quality. Through the action of the flame-retardant sheaths, the parts of the cable that are not in contact with fire will not be damaged, ensuring the service quality of the cable, reducing the use cost. Through the action of multiple groups of limiting baffles, a segmented structure is formed again, and the use effect is good, suitable for promotion.

[0004] For existing cables, their armor layers are usually a whole. The armor layer made of metal braiding has a certain hardness, increasing the overall hardness of the cable, making it difficult to bend the cable during laying. And the ceramicized material protective layer of existing fire-resistant cables is usually also a whole. In the event of a fire, due to the heat conduction of materials such as the internal metal armor layer of the cable, the temperature of the cable in the area where no fire has occurred will also rise. Moreover, the ceramicized material has fluidity when heated, causing the ceramicization process to extend to the area where no fire has occurred, resulting in unnecessary ceramicization, affecting the integrity of the performance and function of other parts of the cable, and increasing the cost of subsequent maintenance and replacement. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect of the prior art that due to heat conduction and the fluidity of the ceramicized material, the performance of the cable in the part not affected by the fire is affected, increasing the maintenance cost. The present invention proposes a halogen-free low-smoke fire-resistant cable.

[0006] To solve the above technical problems, the technical solution adopted by the present invention includes an armored protective layer and a partition component. The armored protective layer and the partition component are arranged at intervals. The partition component is a tubular structure with continuous and zigzag-shaped lines, and the overall shape of the partition component is formed by connecting a series of equidistantly arranged zigzag-shaped units. The zigzag-shaped units enable the partition component to have a certain flexibility and can be telescoped and deformed in the axial and radial directions. The partition component includes a folding cavity, an outer shell, and an inner shell. A V-shaped groove is provided at the downward bend of the outer shell. A ceramicizable powder is placed inside the V-shaped groove. A circulation hole is opened on the side of the outer shell, and a sealing piece is fixedly connected inside the circulation hole. When heated, the sealing piece melts, and the ceramicizable powder can enter the inside of the folding cavity through the circulation hole. A partition plate penetrates through the inside of the folding cavity, and the partition plate is used to evenly partition the space of the V-shaped groove.

[0007] Preferably, the outer wall of the armored protective layer is wrapped with a ceramicizable protective layer. The ceramicizable protective layer and the partition component are arranged at intervals, and the thickness of the part of the partition component that is higher than the armored protective layer is consistent with the thickness of the ceramicizable protective layer.

[0008] Preferably, the outer shell is sleeved outside the inner shell. The outer shell and the inner shell jointly enclose to form a folding cavity. The end of the outer shell is fixedly connected to the armored protective layer, and the end of the inner shell is fixedly connected to the armored protective layer.

[0009] Preferably, the volume of the ceramicizable powder placed in the V-shaped groove accounts for two-thirds of the volume of the V-shaped groove.

[0010] Preferably, the outer wall of the ceramicizable protective layer is wrapped with a sealed protective outer shell, and the sealed protective outer shell is used to seal and protect the entire cable.

[0011] Preferably, the sealed protective outer shell is fixedly connected to the partition plate, and the partition plates are arranged in an annular array with respect to the inner wall of the sealed protective outer shell.

[0012] Preferably, the partition plate is embedded in the sides of the outer shell and the inner shell, and the partition plate is slidably connected to both the outer shell and the inner shell.

[0013] Preferably, the sealed protective outer shell is wrapped outside the folding cavity, and the sealed protective outer shell is slidably connected to the folding cavity.

[0014] Preferably, a wrapping layer is coaxially arranged inside the armored protective layer. The wrapping layer penetrates through the inside of the armored protective layer and extends into the inside of the partition component. The inner shell is slidably connected to the wrapping layer.

[0015] Preferably, a filling material is provided inside the wrapping layer, and the wrapping layer is used to wrap the filling material.

[0016] Preferably, an insulating layer penetrates through the filling material, and a cable core penetrates through the insulating layer.

[0017] Compared with the prior art, the beneficial effects of the present invention include: The present invention is designed with a partition component having a unique structure. The partition component is a continuous zigzag tubular structure, which is arranged at intervals with the armored protective layer. Its zigzag-shaped units enable the cable to have flexibility, and it can expand and contract axially and radially. Multiple bending points can disperse the bending stress, improve the bending flexibility, reduce the bending difficulty, and facilitate installation and arrangement in space-limited occasions. When heated, the sealing piece melts, and the ceramicizable powder can enter the inside of the folding cavity, forming a composite heat-insulating structure with the air in the cavity, significantly improving the heat-insulating effect of the partition component, effectively reducing the heat transfer from the armored protective layer in the fire area to the armored protective layer in the non-fire area, cutting off the heat transfer path, reducing the risk of the cable in the non-fire section being ignited, preventing the spread of the fire, keeping the cable in the non-fire section in performance and structural integrity, extending the overall service life of the cable, reducing the replacement cost and workload. At the same time, the partition component evenly divides the ceramicizable protective layer into several sections, which can prevent the uncontrolled spread of the ceramicization reaction, reduce unnecessary ceramicization, and avoid the cable from becoming rigid and brittle due to overall ceramicization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure of the present invention will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them: Figure 1 Schematically shows a three-dimensional structure diagram of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention; Figure 2 Schematically shows a cross-sectional structure diagram of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention; Figure 3 Schematically shows a longitudinal sectional structure diagram of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention; Figure 4 Schematically shows a structure diagram of a part of the armored protective layer and the partition component of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention; Figure 5 Schematically shows a sectional structure diagram of a part of the partition component of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention; Figure 6 Schematically shows a sectional structure diagram of a part of the ceramicizable powder of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention; Figure 7 Schematically shows a sectional structure diagram of a part of the partition component and the ceramicizable protective layer of a halogen-free low-smoke fire-resistant cable according to an embodiment of the present invention;Figure 8 Schematically shows Figure 5 An enlarged structural schematic diagram of part A in

[0019] In the figure: 1, armored protection layer; 2, separation component; 3, ceramifiable protection layer; 4, sealed protection shell; 5, wrapping layer; 6, filling material; 7, insulating layer; 8, cable core; 201, folding cavity; 202, outer shell; 203, inner shell; 204, partition board; 205, ceramifiable powder; 206, circulation hole; 207, blocking piece; 208, V-shaped groove. Specific embodiments

[0020] It is easy to understand that according to the technical solution of the present invention, without changing the essence of the present invention, those of ordinary skill in the art can propose various structural forms and implementation methods that can be mutually replaced. Therefore, the following specific embodiments and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as all of the present invention or as a limitation or restriction on the technical solution of the present invention.

[0021] According to an embodiment of the present invention in combination with Figures 1 to 8 Shown as

[0022] A halogen-free low-smoke fire-resistant cable includes an armored protection layer 1, which is woven from steel wires and can provide additional compressive protection for the cable. During the laying process of the cable, it may be subjected to various external forces, such as the pressure of the soil during buried laying and the pressure of the building structure. The armored protection layer 1 can effectively withstand these pressures, prevent damage to the internal structure of the cable, and ensure the stable electrical performance of the cable. However, the armored protection layer 1 made of metal has high hardness and rigidity, which makes the whole cable relatively stiff and requires greater external force during the bending process, increasing the construction difficulty. Especially in some places with narrow space and frequent cable bending, it will be more difficult to operate. In some application scenarios with high space requirements, armored cables may not meet the bending radius requirements, thus limiting their scope of use. To solve this problem, the present invention is provided with a separation component 2.

[0023] The armored protective layer 1 and the separating component 2 are arranged at intervals. The separating component 2 has a continuous, zigzag-shaped tubular structure, and the overall shape of the separating component 2 is formed by connecting a series of equidistantly arranged zigzag units. The zigzag units endow the separating component 2 with a certain flexibility, enabling it to expand and contract in the axial and radial directions. The zigzag tubular structure has multiple movable bending points. Compared with a straight cylindrical armored layer, when bending a cable, these bending points can more easily adapt to changes in different directions and angles, allowing the cable to be bent in a smaller space, effectively improving the bending flexibility of the cable and reducing the bending difficulty. Due to the existence of the zigzag tubular structure, when the cable is bent, it can utilize its bending characteristics to achieve a smaller bending radius than a simple straight cylindrical armored layer. This is of great significance in some occasions with limited space, such as narrow pipelines and internal wiring of equipment, enabling the cable to be more conveniently installed and arranged. Moreover, when the cable is bent, the zigzag tubular structure can disperse the bending stress to multiple bending points and line segments, avoiding stress concentration at a certain part. Interleaving with the straight cylindrical armored layer further enhances this stress dispersion effect, enabling the cable to bear external forces more evenly during the bending process, reducing the risk of damage to the armored layer or the internal structure of the cable caused by stress concentration.

[0024] In the case of continuous high temperature during a fire, some protective layers on the outside of the cable will be melted, causing the cable to be ignited in the fire and unable to continue working, affecting its function of supplying power and transmitting signals to fire-fighting equipment, etc. at critical moments. Therefore, a ceramicizable protective layer 3 is wrapped around the outer wall of the armored protective layer 1. The ceramicizable protective layer 3 will undergo a ceramicization reaction at high temperature to form a hard ceramic body. This ceramic body has good high-temperature resistance and can withstand temperatures above one thousand degrees Celsius, effectively isolating flames and heat, preventing the cable from being ignited in a fire, ensuring that the cable can continue to work normally during a fire, supplying power and transmitting signals to fire-fighting equipment, etc., and buying time for personnel evacuation and fire-fighting work. At the same time, the ceramicized layer itself has the characteristics of low smoke and halogen-free, and will not release a large amount of toxic and harmful smoke and hydrogen halide gas in a fire, reducing the harm to personnel and environmental pollution.

[0025] However, in the high-temperature situation of a fire, when the ceramizable protective layer 3 undergoes ceramization, it has a certain fluidity and expands unrestrictedly when heated, which will cause unnecessary ceramization in the areas not affected by the fire. The material after ceramization usually becomes relatively hard and brittle, which will greatly reduce the flexibility of the cable. When it is necessary to lay cables or move existing cables to provide reliable power supply for various fire-fighting equipment, such as fire pumps, smoke exhaust fans, emergency lighting, etc., to ensure the normal operation of these equipment at the fire scene and guarantee the smooth progress of rescue work, the overly hard cable is difficult to bend and lay, increasing the construction difficulty and affecting the rescue time. To solve this problem, the present invention has the following design: The ceramizable protective layer 3 and the partition component 2 are arranged at intervals. The thickness of the part of the partition component 2 that protrudes above the armored protective layer 1 is consistent with the thickness of the ceramizable protective layer 3, and the top of the partition component 2 is in contact with the inner wall of the sealed protective shell 4. The partition component 2 evenly divides the ceramizable protective layer 3 in a cable into several segments. The ceramization material reacts at high temperature to form a ceramic layer. The segmented setting and non-communication with each other can prevent the uncontrolled spread of the ceramization reaction on the entire cable. During a fire, when heat is transferred to the cable, only the segmented ceramization material directly affected by the high temperature will react. Due to the mutual isolation of adjacent segments, unnecessary ceramization caused by heat conduction can be reduced, avoiding the entire cable from being ceramized and becoming rigid and brittle. At the same time, the ceramization material will undergo thermal expansion during the heating process. If the ceramization material of the entire cable is continuous, the thermal expansion may cause excessive internal stress in the material, and then cracks or even peeling may occur in the ceramization layer. The segmented design enables each segment of the ceramization material to expand independently, which can effectively relieve the problem of heat stress concentration and reduce the risk of damage to the ceramization layer, enabling the cable to better maintain its electrical and mechanical properties during a fire and reducing the potential damage to the cable caused by unnecessary ceramization.

[0026] The separation component 2 includes a folding cavity 201, an outer shell 202, and an inner shell 203. The outer shell 202 is sleeved outside the inner shell 203. The outer shell 202 and the inner shell 203 jointly enclose the folding cavity 201. The end of the outer shell 202 is fixedly connected to the armored protective layer 1, and the end of the inner shell 203 is also fixedly connected to the armored protective layer 1. A V-shaped groove 208 is provided at the downward bending part of the outer shell 202. The inside of the V-shaped groove 208 contains a ceramifiable powder 205. The volume of the ceramifiable powder 205 contained in the V-shaped groove 208 accounts for two-thirds of the volume of the V-shaped groove 208. When the separation component 2 is bent under an external force, the powder will disperse the external force to the entire space of the V-shaped groove 208 and the surrounding pipe walls. Since the ceramifiable powder 205 is filled at the bending part, when there is a tendency of excessive bending, the powder will prevent the pipe wall from further deforming, making the force evenly distributed over a larger area, and preventing the external force from possibly concentrating at a certain point or a small area of the bending part, which is likely to cause excessive bending or even rupture at this position; under the action of the ceramifiable powder 205, the force will be dispersed to each part of the separation component 2, reducing the stress received at any position, thereby preventing excessive bending at a certain position of the cable, and further being beneficial to preventing the bending angle from being too small, resulting in damage to the internal structure of the cable.

[0027] The side of the outer shell 202 is provided with a circulation hole 206, and a sealing piece 207 is fixedly connected inside the circulation hole 206. When heated, the sealing piece 207 melts, and the ceramifiable powder 205 can enter the inside of the folding cavity 201 through the circulation hole 206. After the ceramifiable powder 205 is ceramified by heat and flows into the inside of the folding cavity 201, it forms a composite heat insulation structure with the air in the cavity. The ceramifiable powder 205 can form a hard and well-insulating ceramic layer at high temperature, and air is a poor conductor of heat. The combination of the two can significantly improve the heat insulation effect and enhance the heat insulation effect of the partition component 2. Since the partition component 2 and the armored protection layer 1 are arranged at intervals, after the heat insulation effect of the partition component 2 is increased, it can effectively reduce the heat transfer from the armored protection layer 1 in the fire area to the armored protection layer 1 in the non-fire area. Heat transfer is one of the important factors for the spread of fire. If the heat of the armored protection layer 1 is transferred without hindrance, the temperature around the cable in the non-fire section may rise to the ignition point, causing the combustion of the cable outer sheath or surrounding combustibles, resulting in the spread of fire along the cable line. The partition component 2 can effectively cut off the heat transfer path, reduce the risk of the cable in the non-fire section being ignited, prevent the further expansion of the fire, and is beneficial to controlling the scope of the fire. Even after the fire, if the cable in the non-fire section is damaged due to the heat transfer of the armored protection layer 1, it will also affect its subsequent service life. Reducing heat transfer can keep the cable in the non-fire section in good performance and structural integrity. After inspection and necessary repair after the fire, it can continue to be used normally, thereby extending the overall service life of the cable and reducing the cost and workload of replacing the cable. Since the partition component 2 and the ceramifiable protection layer 3 are also arranged at intervals, when the heat insulation effect of the partition component 2 is improved, it can also effectively segment the ceramifiable protection layer 3 and control its ceramification process, reducing the unnecessary ceramification of the ceramifiable protection layer 3 not located in the high-temperature section.

[0028] A partition plate 204 penetrates through the inside of the folding cavity 201. The sealing protection outer shell 4 is fixedly connected to the partition plate 204, and the partition plate 204 is arranged in a circular array with respect to the inner wall of the sealing protection outer shell 4. The partition plate 204 is embedded in the sides of the outer shell 202 and the inner shell 203. The partition plate 204 is slidably connected to both the outer shell 202 and the inner shell 203. The partition plate 204 is used to evenly partition the space of the V-shaped groove 208, thereby blocking the ceramifiable powder 205 located inside the V-shaped groove 208 to prevent it from flowing downward and accumulating at a certain place of the cable, improving the uniformity of its distribution, and thus ensuring its protection and heat insulation effects.

[0029] The outer wall of the ceramifiable protective layer 3 is wrapped with a sealed protective housing 4. The sealed protective housing 4 is used to provide sealed protection for the entire cable. The sealed protective housing 4 is wrapped outside the folding cavity 201, and is slidably connected to the folding cavity 201. The sliding connection between the two is used to ensure that the telescopic performance of the folding cavity 201 is not hindered.

[0030] A wrapping layer 5 is coaxially arranged inside the armored protective layer 1. The wrapping layer 5 runs through the inside of the armored protective layer 1 and extends into the inside of the separating component 2. The inner layer shell 203 is slidably connected to the wrapping layer 5. The inside of the wrapping layer 5 is provided with a filling material 6. The wrapping layer 5 is used to wrap the filling material 6. An insulating layer 7 runs through the inside of the filling material 6, and a cable core 8 runs through the inside of the insulating layer 7.

[0031] The technical scope of the present invention is not limited to the content described above. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A halogen-free, low-smoke, fire-resistant cable, characterized in that: The invention comprises an armored protective layer and a partition component, wherein the armored protective layer and the partition component are arranged at intervals, the partition component is a continuous, zigzag tubular structure, and the overall shape of the partition component is a series of equidistantly arranged zigzag units connected to each other, the zigzag units make the partition component have a certain flexibility, and can be telescopically deformed in the axial and radial directions, the partition component comprises a folding cavity, an outer shell, and an inner shell, the outer shell is provided with a V-shaped groove at the downward bending part, the V-shaped groove contains ceramic powder, and the side of the outer shell is provided with a flow hole A plugging piece is fixedly connected to the inside of the flow hole, and the plugging piece melts when heated, and the ceramic powder can enter the inside of the folding cavity through the flow hole. The inside of the folding cavity is penetrated by a partition plate, and the partition plate is used to evenly divide the space of the V-shaped groove; the outer wall of the armor protection layer is wrapped with a ceramic protection layer, and the ceramic protection layer and the partition component are spaced apart, and the thickness of the partition component that is higher than the armor protection layer is consistent with the thickness of the ceramic protection layer; the volume of the ceramic powder contained in the V-shaped groove accounts for two-thirds of the volume of the V-shaped groove.

2. The halogen-free low-smoke fire-resistant cable according to claim 1, characterized in that: The outer shell is sleeved on the outside of the inner shell, and the outer shell and the inner shell together enclose a folding cavity. The end of the outer shell is fixedly connected to the armored protective layer, and the end of the inner shell is fixedly connected to the armored protective layer.

3. The halogen-free low-smoke fire-resistant cable according to claim 1, characterized in that: The outer wall of the ceramicizable protective layer is wrapped with a sealing protective shell, and the sealing protective shell is used for sealing and protecting the entire cable.

4. The halogen-free low-smoke fire-resistant cable according to claim 3, characterized in that: The sealing protection shell is fixedly connected to the partition plate, and the partition plate is arranged in a ring array with respect to the inner wall of the sealing protection shell.

5. The halogen-free low-smoke fire-resistant cable according to claim 1, characterized in that: The partition plate is embedded in the sides of the outer shell and the inner shell, and the partition plate is slidably connected to the outer shell and the inner shell.

6. The halogen-free low-smoke fire-resistant cable according to claim 3, characterized in that: The sealing protection shell is wrapped around the outside of the folding cavity, and the sealing protection shell is slidably connected to the folding cavity.

7. The halogen-free low-smoke fire-resistant cable according to claim 1, characterized in that: A wrapping layer is coaxially arranged inside the armor protection layer. The wrapping layer penetrates the inside of the armor protection layer and extends to the inside of the partition component. The inner shell and the wrapping layer are slidably connected.

8. The halogen-free low-smoke fire-resistant cable according to claim 7, characterized in that: Filling material is arranged inside the wrapping layer, and the wrapping layer is used to wrap the filling material.

9. The halogen-free low-smoke fire-resistant cable according to claim 8, characterized in that: An insulating layer penetrates the interior of the filling material, and a cable core penetrates the interior of the insulating layer.

Images