Long-service-life water floating light-emitting cable and manufacturing method thereof

Abstract

The invention discloses a long-service-life water floating light-emitting cable and a manufacturing method, and belongs to the technical field of cables, the long-service-life water floating light-emitting cable comprises a conductor, an insulating layer, a protective layer and a waterproof layer which are sequentially arranged from inside to outside, the conductor is a stranded conductor formed by stranding a plurality of strands of monofilaments, the insulating layer is made of crosslinked polyethylene, the insulating layer is of an 8-shaped structure, and the waterproof layer is made of polyethylene. Two annular rings are formed on the cross section of the 8-shaped structure, and the conductors are arranged in the annular rings; the air bags are symmetrically arranged outside the annular ring; the volume fraction configuration of the air bag enables the overall average density of the cable to be not greater than 0.90 g.cm. According to the invention, the sealed air bag extending axially is arranged in the cable, and the cable can float on the water surface, so that a lot of dependence on a shore-based fixed lamp or an external floating body is eliminated, the cost of on-site mounting and fixing components is remarkably reduced, and the mobility is improved; the air bags are continuously distributed in the axial direction to ensure the stability of the linear floating body, and the maintenance frequency and the labor cost are reduced.

Description

Technical Field

[0001] This invention relates to a long-life floating luminous cable and its manufacturing method, belonging to the field of cable technology. Background Technology

[0002] Existing solutions for water lighting and signage mainly include shore-based fixed lighting fixtures, waterproof lighting fixtures mounted on floating bodies, and conventional luminous cables or optical fibers combined with external light sources. Shore-based lights and fixed floating body lights generally rely on external power supplies and rigid fixing structures. Construction requires laying cables, installing bases or floating bodies, which involves a large amount of work and lacks mobility.

[0003] There are certain problems with traditional water-based lighting or signage systems: high installation and maintenance costs; shore-based or floating lights require complex construction and fixing devices, which are not conducive to rapid deployment and relocation; insufficient reliability; the lights and their cables are exposed or immersed in water and sea air environments for a long time, making them susceptible to corrosion from tides, salt spray, ultraviolet rays and biofouling, leading to sealing failure, insulation aging, conductor corrosion and even leakage safety hazards; limited visual effects; point light sources or intermittent deployments make it difficult to form a uniform and continuous linear light emission effect; existing luminous cables, while achieving light emission, usually cannot simultaneously meet the requirements of low specific gravity floating, long-term internal airtightness, and multi-layered structural design to meet electrical safety requirements.

[0004] Therefore, it is necessary to design a long-life floating luminous cable and a manufacturing method to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a long-life floating luminous cable and a manufacturing method thereof, which solves the problems of high installation cost, susceptibility to external influences, limited visual effect, and unsuitability for floating.

[0006] The technical problem to be solved by this invention is achieved by the following technical solution: a long-life floating luminous cable, comprising... From the inside out, it includes a conductor, an insulating layer, a protective layer, and a water-blocking layer. The conductor is a stranded conductor composed of multiple strands of monofilaments, and the insulation layer is made of cross-linked polyethylene. The insulation layer has an "8"-shaped structure, which forms two annular rings in cross-section. The conductor is disposed inside the annular rings. Airbags are symmetrically disposed outside the annular rings. The protective layer wraps around the airbags and the insulation layer. Energy-storing luminescent powder is dispersed in the protective layer. The volume fraction of the airbags is configured such that the overall average density of the cable is not greater than 0.90 g·cm⁻³.

[0007] Preferably, the conductor has seven strands, with a single filament at the center and the remaining filaments arranged around the outside of the central conductor.

[0008] Preferably, the conductor is annealed after being filamented, and the temperature is raised to 280°C during the annealing process, held for 2-4 hours, and then cooled naturally.

[0009] Preferably, the insulating layer is made of cross-linked polyethylene material.

[0010] Preferably, the "8"-shaped structure has connecting ribs that connect the two annular rings to form the insulating layer.

[0011] Preferably, the protective layer is made of natural-colored medium-density polyethylene, and ultrafine red energy-storing phosphorescent powder is dispersed in the protective layer.

[0012] Preferably, the airbags extend along the cable axis to form a linear distribution, and the airbags are disposed on both sides of the connecting rib.

[0013] Preferably, the water-blocking layer is disposed on the outer periphery of the protective layer, and is made of polyether-type polyurethane, which is disposed on the outside of the protective layer by extrusion.

[0014] Preferably, the thickness of the insulating layer is 0.6-0.7 mm, the thickness of the protective layer is 1.2-1.3 mm, and the thickness of the water-blocking layer is 0.4-0.5 mm.

[0015] A method for preparing a long-life floating luminescent cable, preferably comprising the following steps: S1. The raw material is drawn into multiple monofilaments. The monofilaments are then subjected to aging annealing. The annealing process involves heating to 280℃ and holding for 2-4 hours, followed by natural cooling outside the furnace. S2. Twist the annealed monofilaments into the conductor according to a predetermined number of strands; S3. The insulating layer is extruded onto the conductor and an "8"-shaped cavity is formed using a non-concentric anisotropic mold; the insulating layer is then subjected to rapid cross-linking and shaping by ultraviolet irradiation after extrusion. S4. Mix the natural-colored medium-density polyethylene with ultrafine red energy-storing phosphorescent powder, extrude the protective layer using a semi-extrusion die, and blow air into the die core during the extrusion process of the protective layer to form the airbag between the protective layer and the insulating layer. S5. After the protective layer is formed, the water-blocking layer is extruded as an outer cover layer to ensure the integrity and water resistance of the water-blocking layer.

[0016] The beneficial effects of this invention are: This invention incorporates an axially extended, closed airbag within the cable, specifically an inflatable cavity formed between the protective layer and the insulation layer. This reduces the overall average density of the cable to no more than 0.90 g·cm⁻³, allowing the cable to float on the water surface. This eliminates the heavy reliance on shore-based fixed lighting fixtures or external floating bodies, significantly reducing on-site installation and component costs while improving mobility. The continuous axial distribution of the airbags ensures the stability of the linear floating body, allowing the cable to flexibly adapt to wave undulations, reducing localized stress, facilitating winding, laying, and recycling, and lowering maintenance frequency and labor costs.

[0017] This invention employs an insulating layer that undergoes rapid UV cross-linking and shaping after extrusion, with connecting ribs incorporated within the insulating layer. This enhances the electrical durability and thermomechanical stability of the insulating layer, reducing the risk of insulation degradation caused by moisture, temperature, and mechanical fatigue, thereby minimizing leakage hazards and extending service life. The stranded conductor, composed of multiple strands of monofilament, provides sufficient conductivity and mechanical flexibility while reducing material weight, making the conductor suitable for both power transmission and use in flexible floating bodies. Annealing treatment improves the mechanical properties of the monofilaments, increasing the tensile strength and fatigue life of the stranded wire, supporting long-term use in marine and atmospheric environments. An outer transparent or semi-transparent polyether-type polyurethane water-blocking layer, tightly bonded to the protective layer through extrusion, combined with the dense surface of the protective layer, provides an overall waterproof, salt spray-proof, and UV-resistant barrier, preventing moisture penetration into the protective and insulating layers, reducing insulation degradation and conductor corrosion caused by water seepage, and improving the reliability of the cable during long-term service on water. The water-blocking layer's light transmittance allows light from the luminescent layer to pass through, maintaining its luminescent effect while protecting the luminescent material from direct water contact and mechanical abrasion.

[0018] By using this invention, a protective layer made of natural-colored medium-density polyethylene is uniformly dispersed in its melt, forming a continuous light-emitting band along the cable axis. This replaces discrete point light sources, significantly improving visual continuity and recognition, and addressing the problem that existing point light sources cannot form a uniform linear light band. The luminescent material absorbs light energy during the day and releases light energy at night, reducing dependence on external lighting power supplies, saving energy, and reducing the installation and maintenance of external lighting fixtures.

[0019] The present invention achieves the following effects by setting an "8"-shaped cross-linked polyethylene insulation layer: the conductor is precisely positioned within two annular rings to form separate conductor compartments, which is beneficial for interlayer positioning and electrical isolation, and reduces the mechanical and electrical risks caused by the mutual displacement of conductors; the "8"-shaped cavity and connecting ribs provide boundaries for the airbag arrangement and structural support, so that the gas cavity, conductor and insulation cooperate with each other, taking into account both insulation strength and floating volume distribution. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention.

[0021] Figure 2 This is a table showing the weight and cable density of the present invention.

[0022] Figure 3 This is a process table for annealing conductor monofilaments according to the present invention.

[0023] In the diagram: 1-Conductor, 2-Insulating layer, 3-Protective layer, 4-Water-blocking layer, 5-Airbag. Detailed Implementation

[0024] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this invention, the invention will be further described below in conjunction with specific embodiments. Example 1

[0025] like Figure 1 As shown, a high-lifespan floating luminescent cable comprises, from the inside out, a conductor 1, an insulation layer 2, a protective layer 3, and a water-blocking layer 4. The conductor 1 is a stranded conductor composed of multiple strands of monofilaments. The insulation layer 2 is made of cross-linked polyethylene and has an "8"-shaped structure. The "8" shape forms two annular rings in cross-section. The conductor 1 is positioned inside the annular rings, and air pockets 5 are symmetrically positioned outside the annular rings. The protective layer 3 wraps around the air pockets 5 and the insulation layer 2, and contains energy-storing luminescent powder. The air pockets 5 ensure that the overall average density of the cable does not exceed 0.90 g·cm⁻³.

[0026] Weight and cable density, such as Figure 2 As shown.

[0027] Reference Figure 1 The cable is an axially extending cable, with an overall cross-section as shown. Figure 1 As shown, an axially extending closed or semi-closed airbag 5 is formed inside the insulation layer 2 and the protective layer 3. By setting the airbag 5, the overall average density of the cable is not greater than 0.90 g・cm⁻³, which enables the cable to float on the water surface.

[0028] Conductors 1 are disposed within the annular rings at both ends of the "8" shape formed by the insulation layer 2. Conductors 1 extend continuously along the cable axis. In this embodiment, both conductors 1 employ a seven-strand structure, with a single filament at the center and six other filaments evenly surrounding it to form a circular cross-section. The conductors 1 are made of AA8030 type aluminum alloy single filaments.

[0029] After the conductor 1 is formed into monofilaments, the monofilaments constituting conductor 1 need to undergo aging annealing to ensure that the monofilaments constituting conductor 1 have certain strength and flexibility. In this embodiment, the annealing step of the monofilament 1 is to heat to about 280 ℃, hold at that temperature for 2–4 hours, and then allow it to cool naturally outside the furnace. After annealing, the monofilaments are stranded into a stranded conductor according to a predetermined number of strands.

[0030] Conductor monofilament annealing process, such as Figure 2 As shown.

[0031] Conductor 1 can transmit electrical energy. The cross-section of conductor 1 is circular and bundled, which can be placed in the cavity of the annular ring of insulating layer 2. The connecting ribs of insulating layer 2 can maintain the positioning of conductor 1 in the cross-section and prevent the conductor from radially shifting during extrusion or use.

[0032] The insulating layer 2 adopts an "8" shaped cross-section structure, that is, two mutually separated annular cavities are formed in the cross-section, and conductor 1 is correspondingly placed in each annular cavity. The two annular cavities are connected by a connecting rib to form an overall "8" shape. The connecting rib also serves as a structural support and interlayer positioning structure.

[0033] The insulation layer 2 is made of cross-linked polyethylene. The insulation layer is extruded using a non-concentric anisotropic extrusion die to form an "8" shaped cross-section structure. After extrusion, it undergoes rapid cross-linking and shaping treatment by ultraviolet irradiation to ensure the uniformity of cross-linking and dimensional stability of the thick film.

[0034] In this embodiment, the insulation layer thickness is 0.6-0.7 mm, and the connecting rib has a cross-sectional thickness of 0.9-1.0 mm and a width of 7.8-8.0 mm. The insulation layer 2 provides electrical insulation and mechanical support for the conductor 1; the "8"-shaped cross-section structure and the connecting rib define the position of the conductor 1 and provide boundary conditions for the airbag 5; the connecting rib improves the interlayer mechanical fit strength and serves as a positioning reference for the airbag 5.

[0035] Reference Figure 1 The airbags 5 are symmetrically arranged on the outside of the two rings of the "8"-shaped structure, specifically on both sides of the connecting rib. The top of the airbags contacts the two annular rings on both sides, forming a ring shape in cross-section. In the axial direction, the airbags 5 extend along the cable to form a continuous linear air cavity band. Overall, the cable has two airbags 5 with a certain space, and through contact with the protective layer 3 and the insulation layer 2, it ensures that the cable as a whole can float on the water surface.

[0036] The airbag 5 is formed during the extrusion molding process of the protective layer 3 using a semi-extrusion die, with air blowing and pressurization within the die core. Gas is introduced into the die core cavity to maintain the internal volume. The blowing device consists of a connector, a blower or air source, and a pressure regulating switch. The blowing process is synchronized with the melt extrusion of the protective layer, forming a composite cross-section of the protective layer-airbag-insulating layer. After the protective layer is formed and cooled, the airbag port is sealed by an end sealing structure, forming a sealed inflation chamber. The gas can be dry air or nitrogen.

[0037] The airbag 5 can form a gas cavity between the protective layer 3 and the insulation layer 2 and adjust the gas volume fraction so that the overall average density of the cable is no more than 0.90 g·cm⁻³, thereby generating sufficient buoyancy on the water surface and maintaining axial floating stability; the continuous arrangement of the airbag 5 also helps to improve bending adaptability and wave response performance.

[0038] In this embodiment, the protective layer 3 is made of natural-colored medium-density polyethylene material and continuously wraps around the insulation layer 2 and the air bladder 5 along the outer perimeter of the cable. The specific thickness of the protective layer 3 is 1.2-1.3 mm.

[0039] During the fabrication of protective layer 3, ultrafine red energy-storing luminescent powder is uniformly dispersed within the melt of protective layer 3 as a luminescent agent, enabling the cable surface to absorb light energy during the day and release it at night, achieving self-luminescence. The luminescent powder undergoes sieving before being added to the protective layer melt, specifically using a mixed 39-mesh and 62-mesh sieve to prevent clogging at the extrusion die and improve dispersibility. The amount of luminescent powder added to the protective layer ranges from 0.5 wt% to 15 wt%. The particle size of the luminescent powder ranges from 5 μm to 200 μm.

[0040] During the formation process, the protective layer 3 is set by a semi-extrusion mold and a core blowing method, so that while the protective layer 3 has a continuous appearance, the cavity wall of the air bladder 5 is formed on its inner side. The outer surface of the protective layer 3 remains continuous and dense, ensuring that the luminescent body forms a continuous luminous band on the outer layer.

[0041] The protective layer 3 provides mechanical protection and contains energy-storing luminescent powder that can release light energy at night to achieve self-luminescence, protect the outer wall of the airbag 5, and provide an adhesive base for the water-blocking layer 4.

[0042] A water-blocking layer 4 is also provided on the outside of the protective layer 3. The water-blocking layer 4 covers the outer surface of the protective layer 3 and is formed by extrusion. The water-blocking layer 4 serves to provide both water resistance and weather protection. The water-blocking layer 4 is made of transparent polyether-type polyurethane and is formed as an integral coating on the outside of the protective layer through an extrusion process. The thickness of the water-blocking layer 4 is 0.4-0.5 mm.

[0043] When extruding the water-blocking layer 4, ensure that the water-blocking layer 4 and the protective layer 3 are tightly bonded to avoid delamination or damage to the airbag during traction and cooling. The water-blocking layer 4 and the protective layer 3 are bonded together by hot melt extrusion, and adhesive is used where necessary to improve the interlayer bonding strength.

[0044] The water-blocking layer 4 isolates the external water environment and prevents water from seeping into the protective layer 3 and the insulation layer 2, thereby ensuring the electrical safety of the cable when it works in water for a long time. Since the water-blocking layer 4 is transparent and can transmit light, it allows the luminous light inside the protective layer 3 to be transmitted outward, forming a visible linear luminous effect.

[0045] In this embodiment, the cable is provided with an annular seal at the end. The annular seal is a glue-filled end cap. The annular seal forms a tight seal with the exposed end faces of the water-blocking layer 4, the protective layer 3, and the insulation layer 2 to prevent water from entering the airbag 5 along the core wire. The glue-filled end cap is also provided with an interface for the airbag 5, which can be used to fill the airbag with gas and perform airtightness testing during the manufacturing and inspection stages.

[0046] A method for preparing a long-life floating luminescent cable includes the following steps: S1. The raw material is drawn into multiple conductor wires. In this embodiment, AA8030 aluminum alloy rod is drawn into wires. The conductor wires are placed in an annealing furnace, heated to about 280 ℃ and held for 2-4 hours, and then allowed to cool naturally outside the furnace. S2. The annealed monofilaments are twisted into conductor 1 according to a predetermined number of strands, and straightened and shaped to meet the requirements of twisting tightness and outer diameter tolerance. In this embodiment, 7 monofilaments are twisted together, with one monofilament at the center and the remaining six monofilaments surrounding the surface of the monofilament twisted at the center.

[0047] S3. Cross-linked polyethylene insulation is extruded from a non-concentric anisotropic die with an "8" shape. The extrusion temperature, die gap and traction speed are strictly controlled. After extrusion, the insulation layer is subjected to ultraviolet irradiation for rapid cross-linking and shaping treatment to ensure that the size and thickness of the "8" shaped cavity are uniform.

[0048] S4. Medium-density polyethylene (MDPE) in its natural color and ultrafine red energy-storing luminescent powder are uniformly dispersed in a melt stirring system. In this embodiment, 0.5-15 wt% is added to the melt flow according to the set dosage. A semi-extrusion die is used to extrude the protective layer 3 from the insulating layer 2, while simultaneously blowing air into the die core to form an axially extending airbag 5 cavity between the protective layer 3 and the insulating layer 2. The blowing volume and pressure are controlled to maintain a stable cross-sectional shape of the airbag 5 cavity, while ensuring that the surface of the protective layer 3 is dense and free of air bubbles. S5. After the protective layer 3 has cooled and initially shaped, an extruder is used to extrude a water-blocking layer 4 of polyether polyurethane on the outside of the protective layer 3 according to the set die coefficient and traction ratio, so that it is closely attached to the protective layer 3 and forms a smooth outer surface.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A long-life floating luminescent cable, comprising: From the inside out, it includes a conductor, an insulating layer, a protective layer, and a water-blocking layer. Its features are: The conductor is a stranded conductor composed of multiple strands of monofilaments, and the insulation layer is made of cross-linked polyethylene. The insulation layer has an "8"-shaped structure, which forms two annular rings in cross-section. The conductor is disposed inside the annular rings. Air bladders are symmetrically disposed outside the annular rings. The protective layer wraps around the air bladders and the insulation layer. Energy-storing luminescent powder is dispersed in the protective layer. The volume fraction of the air bladders is configured such that the overall average density of the cable is not greater than 0.90 g·cm⁻³.

2. The long-life floating luminescent cable according to claim 1, characterized in that: The conductor consists of seven strands, with a single filament at the center and the remaining filaments arranged around the outside of the central conductor.

3. The long-life floating luminescent cable according to claim 1, characterized in that: The conductor is annealed after being filamented. During the annealing process, the temperature is raised to 280°C and held for 2-4 hours, followed by natural cooling.

4. The long-life floating luminescent cable according to claim 1, characterized in that: The insulating layer is made of cross-linked polyethylene material.

5. A long-life floating luminescent cable according to claim 4, characterized in that: The "8" shaped structure is provided with connecting ribs that connect the two annular rings to form the insulating layer.

6. The long-life floating luminescent cable according to claim 1, characterized in that: The protective layer is made of natural-colored medium-density polyethylene, and ultrafine red energy-storing phosphorescent powder is dispersed in the protective layer.

7. A long-life floating luminescent cable according to claim 5, characterized in that: The airbags extend along the cable axis to form a linear distribution, and the airbags are disposed on both sides of the connecting rib.

8. A long-life floating luminescent cable according to claim 1, characterized in that: The water-blocking layer is disposed on the outer periphery of the protective layer and is made of polyether polyurethane, which is extruded onto the outside of the protective layer.

9. A long-life floating luminescent cable according to claim 1, characterized in that: The thickness of the insulating layer is 0.6-0.7 mm, the thickness of the protective layer is 1.2-1.3 mm, and the thickness of the water-blocking layer is 0.4-0.5 mm.

10. A method for preparing a long-life floating luminescent cable, characterized in that: The method for preparing a long-life floating luminescent cable as described in any one of claims 1-9 comprises the following steps: S1. The raw material is drawn into multiple monofilaments. The monofilaments are then subjected to aging annealing. The annealing process involves heating to 280℃ and holding for 2-4 hours, followed by natural cooling outside the furnace. S2. Twist the annealed monofilaments into the conductor according to a predetermined number of strands; S3. The insulating layer is extruded onto the conductor and an "8"-shaped cavity is formed using a non-concentric anisotropic mold; the insulating layer is then subjected to rapid cross-linking and shaping by ultraviolet irradiation after extrusion. S4. Mix the natural-colored medium-density polyethylene with ultrafine red energy-storing phosphorescent powder, extrude the protective layer using a semi-extrusion die, and blow air into the die core during the extrusion process of the protective layer to form the airbag between the protective layer and the insulating layer. S5. After the protective layer is formed, the water-blocking layer is extruded as an outer cover layer to ensure the integrity and water resistance of the water-blocking layer.

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