Submarine cable magnetic attraction fixing device

Abstract

The invention relates to the technical field of power cables, in particular to a submarine cable magnetic attraction fixing device which comprises a magnetic body, a buffer bonding layer and a titanium alloy coating layer. The titanium alloy coating layer comprises a protective shell, an outer shell and an iron body, the center of the iron body is fixedly connected with a clamping frame in a penetrating mode, the protective shell wraps the outer side of the iron body, a bolt frame is installed in the clamping frame, and the bottom of the protective shell wraps the outer shell; the magnetic main body comprises two magnets, the clamping frame penetrates through iron bodies, the two magnets are located below the iron bodies, and the two iron bodies are fixed in an inner cavity of the protective shell through buffer bonding layers; and the buffer bonding layer is formed by curing an epoxy group elastic bonding agent. Through the magnetic main body, the buffer bonding layer and the titanium alloy coating layer, the corrosion resistance, the deep pressure bearing, the impact resistance, the sealing reliability and the whole service life cost are obviously improved, and the problems that a deep sea magnetic assembly is easy to corrode, easy to break and difficult to maintain are solved.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and in particular to a magnetic fixing device for submarine cables. Background Technology

[0002] Magnetic components are increasingly used in marine engineering and seabed exploration due to their convenient adsorption and fixation functions. Applications include temporary fixation of seabed sensors, adsorption and positioning of underwater tools, and assistance in the splicing of marine components. However, the seabed environment is much harsher than the terrestrial environment, exhibiting the following characteristics: First, high corrosivity. Seawater contains large amounts of chloride ions, sulfate ions, and various salts, as well as acidic substances secreted by marine organisms, which can strongly corrode metal materials. Second, high pressure. Seabed pressure increases significantly with depth, increasing by approximately 0.1 MPa for every 10 meters of depth, reaching tens or even hundreds of MPa in deep waters, easily leading to component deformation or damage. Third, large environmental fluctuations. The seabed is subject to complex factors such as water flow impact, temperature changes, and sediment abrasion, further exacerbating component performance degradation.

[0003] Existing magnetic assemblies for underwater use mostly use stainless steel or ordinary alloy steel as the cladding material. Although the cost is low, stainless steel still poses a risk of pitting corrosion and stress corrosion in seawater environments. The internal magnetic core oxidizes and corrodes upon contact with seawater, leading to a rapid decrease in magnetic performance. During assembly or deployment, if the coating is scratched by fishing nets or reefs, the protective chain instantly fails, and on-site recoating is impossible. The hard-on-hard contact between the shell and the magnet, along with pressure pulsations and impacts, easily causes cracking, water seepage, or chipping between the layers. Therefore, developing a magnetic assembly for underwater use with excellent corrosion resistance, structural strength, and pressure buffering performance is a key requirement to overcome the shortcomings of existing technologies. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of existing magnetic assemblies for submarine cables being easily damaged in high-corrosion and high-pressure environments and having rapid magnetic attenuation, and to propose a magnetic fixing device for submarine cables.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a magnetic fixing device for submarine cables, comprising: Magnetic body, buffer bonding layer and titanium alloy coating layer; The titanium alloy cladding layer includes a protective shell, an outer shell, and an iron body. The iron body is a hollow cavity structure with one end open. A snap-fit ​​bracket is fixedly connected through the center of the iron body. The protective shell covers the outside of the iron body. A bolt bracket is snapped into the inside of the snap-fit ​​bracket. The bolt bracket penetrates the protective shell. The bottom of the protective shell covers the outer shell. The magnetic body includes two magnets. The shape of the inner cavity on the upper side of the protective shell is adapted to the shape of the iron body. The snap-fit ​​bracket penetrates the iron body, and the two magnets are located below the iron body. The two magnets are symmetrically distributed with the bolt bracket as the center. The two iron bodies are fixed in the inner cavity of the protective shell by a buffer adhesive layer. The buffer adhesive layer is formed by curing an epoxy-based elastic adhesive and has a thickness of 0.5-2 mm.

[0006] In the aforementioned magnetic fixing device for submarine cables, the bolt bracket is made of high-strength and corrosion-resistant T1 material. The bolt bracket has a gap inside the snap-fit ​​bracket filled with sealant. The bolt bracket is sealed to the protective shell. The portion of the bolt bracket extending out of the protective shell is a threaded portion.

[0007] In the aforementioned magnetic fixing device for submarine cables, the outer shell is made of TC4 titanium alloy with a thickness of 1-3mm, which has an extremely low corrosion rate in seawater and can form a dense oxide film on its surface. The magnet is made of neodymium iron boron permanent magnet material with strong magnetism and its surface is electroplated with nickel.

[0008] In the above-mentioned magnetic fixing device for submarine cables, the magnet is bonded to the outer shell, the magnet is adhered to the bottom of the iron body, the exposed part of the iron body is sprayed with Teflon with a thickness of 0.05-0.064mm, and the thickness of the bottom step after the outer shell is coated with glue is between 0.2-0.4mm.

[0009] In the aforementioned magnetic fixing device for submarine cables, the protective shell is made of a mixture of EPDM and EPDM 4045 rubber. The inner surface of the top cavity of the protective shell is provided with an annular groove with a depth of 0.3-0.8 mm and a width of 1-2 mm. The annular groove is filled with a buffer adhesive layer to form a mechanical interlocking structure to improve the stability of the interlayer bonding.

[0010] In the aforementioned magnetic fixing device for submarine cables, the buffer bonding layer uses an epoxy-based elastic adhesive to absorb mechanical stress generated by pressure changes and water flow impact.

[0011] In the aforementioned magnetic fixing device for submarine cables, the specifications of the magnet and the thickness of the titanium alloy cladding layer can be freely adjusted according to actual needs, making it suitable for seabed exploration and marine engineering scenarios at different depths.

[0012] In the aforementioned magnetic fixing device for submarine cables, the open end of the titanium alloy cladding layer is sealed by a sealing structure, and the outer shell can be opened to install components and create a bottom groove as needed for the application scenario.

[0013] Compared with existing technologies, the advantages of this invention are: 1. This invention uses TC4 titanium alloy and a corrosion-resistant elastic protective shell as the coating material, which has excellent corrosion resistance. The titanium alloy shell has an extremely low corrosion rate in seawater, and its surface can form a dense oxide film, which can effectively resist the erosion of chloride ions and marine organism secretions. It relies on the self-passivating oxide film to block chloride ions. - The channel eliminates underwater maintenance and downtime losses, and compared to stainless steel cladding, it extends the corrosion resistance of the project by 5-8 times. 2. The present invention has a tensile strength of over 860MPa through the TC4 titanium alloy shell. With a reasonable thickness design of 1-3mm, it can withstand the pressure environment of the deep sea up to 1000 meters, avoiding structural deformation or damage. In order to improve pressure resistance, traditional solutions often increase the stainless steel wall thickness to over 5mm, which greatly reduces the total weight of the component and increases the depth margin by the same amount. 3. The buffer bonding layer prepared by the present invention using epoxy-based elastic adhesive has good buffering performance and excellent bonding strength and elastic deformation ability. It can absorb the mechanical stress generated by pressure changes and water flow impact, and prevent the magnetic body from breaking due to rigid impact. Existing technology uses rigid epoxy or cement to seal, which accelerates the fracture when hard impacts occur. The presence of elastic adhesive can compensate for the difference in thermal expansion and contraction caused by temperature changes and prevent interlayer delamination. 4. This invention uses a buffer adhesive layer to fix the magnetic body and the covering layer. Combined with the threaded connection sealing structure, it can be quickly assembled. Conventional flange designs have many parts and high groove machining precision. The deep-sea assembly window is short, and leakage will occur once the pressure is misaligned. The connection between the shell and the magnet is simple. The adhesive completes the filling and sealing simultaneously. The number of parts is halved. The on-site assembly time is reduced from hours to minutes. The sealing reliability is high and it can effectively prevent seawater from seeping into the inner cavity. 5. The specifications of the magnetic body and the thickness of the titanium alloy coating can be adjusted according to actual needs. The thickness of the titanium layer and the specifications of the magnet can be linearly adjusted according to the target water depth without the need to redevelop the mold. An anti-biological coating can be added to the outer surface to effectively reduce the amount of adhesion. It is applicable to multiple scenarios such as subsea pipeline inspection, wellhead magnetic marking, and wind power foundation monitoring, and has strong practicality. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of a magnetic fixing device for submarine cables proposed in this invention; Figure 2 This is a schematic diagram of the unfolded structure of a magnetic fixing device for submarine cables proposed in this invention; Figure 3 This is a schematic diagram of the unfolded structure of a magnetic fixing device for submarine cables proposed in this invention from another perspective. Figure 4 This is a schematic diagram of the internal structure of a protective shell for a magnetic fixing device for submarine cables proposed in this invention. Figure 5 This is a schematic diagram of the protective shell and clamping frame of the magnetic fixing device for submarine cables proposed in this invention; Figure 6 This is a schematic diagram of the iron body and magnet part of a magnetic fixing device for submarine cables proposed in this invention; Figure 7 This is a schematic diagram of the iron body and magnet from another perspective of the magnetic fixing device for submarine cables proposed in this invention; Figure 8 This is a schematic diagram of the bolt bracket of a magnetic fixing device for submarine cables proposed in this invention.

[0015] In the diagram: 1. Iron body; 2. Magnet; 3. Bolt; 4. Protective shell; 5. Outer shell; 6. Bottom groove; 7. Clip bracket. Detailed Implementation

[0016] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0017] Example Reference Figure 1-4 A structural diagram and unfolded diagram of a magnetic fixing device for submarine cables, specifically including a magnetic body, a buffer bonding layer and a titanium alloy coating layer; Existing technologies for underwater magnetic assemblies employ coating protection, such as spraying an anti-corrosion coating onto the surface of a metal cladding layer. However, this coating is prone to scratches and peeling during assembly or underwater operations, resulting in poor protective durability. To address this, a titanium alloy cladding layer is introduced for deeper protection. This layer comprises a protective shell 4, an outer shell 5, and an iron body 1. The iron body 1 is a hollow cavity structure with one open end. A snap-fit ​​bracket 7 is fixedly connected through the center of the iron body 1. The shape of its inner cavity matches the outer shell 5 and the magnetic body. The magnetic body is fixed within the inner cavity of the titanium alloy cladding layer via a buffer adhesive layer. Its ends are bonded to the protective shell, and its top is bonded to the iron body 1. The protective shell 4 is made of a mixture of EPDM and EPDM 4045 rubber. The inner surface of the protective shell 4 has an annular groove with a depth of 0.3-0.8mm and a width of 1-2mm. The buffer adhesive layer is filled in the annular groove to form a mechanical interlocking structure, which improves the stability of the interlayer bonding. The snap-fit ​​bracket 7 has a bolt bracket 3 installed inside, which penetrates the protective shell 4. The bottom of the protective shell 4 is covered by the outer shell 5. The magnetic fixing device fixes the magnetic body to the covering layer through the buffer adhesive layer. With the threaded connection sealing structure, the assembly process is simple and efficient, and the sealing reliability is high, which can effectively prevent seawater from seeping into the inner cavity. Reference Figure 6 , 7A magnetic fixing device for submarine cables includes a magnet and an iron body. The magnetic body comprises two magnets 2, which are made of NdFeB material and can operate in a temperature range of -40~100℃, which is suitable for the high-pressure and low-temperature working environment of the submarine. The shape of the inner cavity on the upper side of the protective rubber shell 4 is adapted to the shape of the iron body 1, making assembly more convenient. The two magnets 2 are located below the iron body 1. The two magnets 2 are also fixed to the iron body 1 by a buffer adhesive layer, and the two magnets 2 are symmetrically distributed with the bolt bracket 3 as the center. The buffer adhesive layer is formed by curing an epoxy-based elastic adhesive, and its thickness is 0.5-2mm. The buffer adhesive layer uses an epoxy-based elastic adhesive, which has both excellent bonding strength and elastic deformation ability. It can absorb the mechanical stress generated by pressure changes and water flow impact, and prevent the magnetic body from breaking due to rigid impact. At the same time, the presence of elastic adhesive can compensate for the difference in thermal expansion and contraction caused by temperature changes and prevent interlayer peeling.

[0018] Reference Figure 5 and 8 A bolt holder and a snap-fit ​​holder are disclosed for a magnetic fixing device for submarine cables. Both the snap-fit ​​holder 7 and the bolt holder 3 are made of high-strength, corrosion-resistant T1 material. The portion through which the bolt holder 3 and the snap-fit ​​holder 7 pass is filled with sealant to provide a certain buffering capacity. The sealant can also compensate for the difference in thermal expansion and contraction caused by temperature changes. The bolt holder 3 is installed inside the snap-fit ​​holder 7, fitting snugly against the internal structure of the snap-fit ​​holder 7 and is isolated from the outside after being filled with sealant. The bolt holder 3 passes through the protective shell 4, and the portion extending out of the protective shell 4 is a threaded portion with a thread diameter of φ8.91~8.95 before thread rolling, a minimum effective thread length of 30mm, and a bolt breaking tensile strength greater than 500kg, providing a good fixing structure for the fixing device.

[0019] Magnetic components used on the seabed mostly use stainless steel or ordinary alloy steel as the cladding material. Although the cost is low, stainless steel still has the risk of pitting corrosion and stress corrosion in the seawater environment, especially in the deep sea area with low oxygen content, where the corrosion rate is significantly accelerated and the cladding layer may be damaged in a short period of time. The outer shell 5 is made of TC4 titanium alloy with a thickness of 1-3mm. It has an extremely low corrosion rate in seawater and a dense oxide film can be formed on its surface. Common neodymium iron boron permanent magnets oxidize and corrode after contact with seawater, resulting in a sharp decline in magnetic properties. The two sharp edges of the magnet have a natural chamfer of about R0.5. Although it is made of neodymium iron boron permanent magnet material with strong magnetism, the surface is treated with Ni-Cu-Ni. Experiments show that there is no red rust after 48 hours of neutral salt spray test after electroplating nickel treatment, which has good corrosion resistance. The material is not easily corroded during daily storage and transportation, and even if there is an accidental leak, the internal fixed device will not be easily corroded.

[0020] During installation, magnet 2 is first bonded to the outer shell 5. Then, magnet 2, along with the outer shell 5, is bonded to the bottom groove of iron body 1 with a buffer adhesive layer on one side. Iron body 1 is produced with high precision and automation. The exposed surface is coated with Teflon rust prevention with a thickness of 0.05-0.064mm. After the iron body 1 is coated with glue, the thickness of the bottom step is between 0.2-0.4mm.

[0021] The seabed environment is easily subjected to pressure and water flow impacts from different directions and magnitudes. Most fixed magnetic assemblies do not consider pressure buffering design, and the connection between the coating layer and the magnetic body is rigid. Under complex and variable pressure impacts, gaps between layers or breakage of the magnetic body are easily generated. Introducing a buffer bonding layer made of epoxy-based elastic adhesive can absorb the mechanical stress generated by pressure changes and water flow impacts, compensate for the thermal expansion and contraction differences caused by temperature changes, and prevent interlayer delamination.

[0022] The diameter and length of magnet 2 and the thickness of outer shell 5 can be linearly scaled within the three-dimensional design space of "strength-corrosion-magnetic properties". An amorphous carbon film can be superimposed on the outer surface of protective shell 4 to further reduce the adhesion rate of marine organisms, and the cleaning cycle is extended to ensure the stability of use. The specifications of magnet 2 and the thickness of titanium alloy cladding can be freely adjusted according to actual needs, making it suitable for seabed exploration and marine engineering scenarios at different depths. The buffer bonding layer fixes the magnetic body and the cladding layer. With the threaded connection sealing structure, it can be quickly assembled. Conventional flange designs have many parts and high groove machining precision. The assembly window in deep sea is short, and leakage will occur once the pressure is misaligned. The connection between the outer shell and the magnet is simple. The adhesive completes the filling and sealing simultaneously, halving the number of parts and reducing the on-site assembly time from hours to minutes. The open end of the titanium alloy cladding layer is sealed by a sealing structure, which has high sealing reliability and can effectively prevent seawater from seeping into the inner cavity. The outer shell 5 can be opened with a bottom groove 6 according to the usage scenarios of the required opening to install components. Different specifications of outer shell 5 can provide irregular structures to add new seabed connectors, so that the fixing device is not limited to a single fixing function and can be expanded with additional structures to achieve combined functions.

[0023] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetic fixing device for submarine cables, characterized in that, include: Magnetic body, buffer bonding layer and titanium alloy coating layer; The titanium alloy cladding layer includes a protective shell (4), an outer shell (5), and an iron body (1). The iron body (1) is a hollow cavity structure with one end open. A snap-fit ​​bracket (7) is fixedly connected through the center of the iron body (1). The protective shell (4) covers the outside of the iron body (1). A bolt bracket (3) is snap-fitted inside the snap-fit ​​bracket (7). The bolt bracket (3) penetrates the protective shell (4). The bottom of the protective shell (5) covers the outer shell (5). The magnetic body includes two magnets (2), the shape of the inner cavity on the upper side of the protective shell (4) is adapted to the shape of the iron body (1), the snap-fit ​​bracket (7) penetrates the iron body (1), the two magnets (2) are located below the iron body (1); and the two magnets (2) are symmetrically distributed with the bolt bracket (3) as the center, and the two iron bodies (1) are fixed in the inner cavity of the protective shell (4) by a buffer adhesive layer; The buffer adhesive layer is formed by curing an epoxy-based elastic adhesive and has a thickness of 0.5-2 mm.

2. The magnetic fixing device for submarine cables according to claim 1, characterized in that, The bolt bracket (3) is made of high-strength and corrosion-resistant T1 material. The bolt bracket (3) is filled with sealant in the snap-fit ​​gap inside the snap-fit ​​bracket (7). The bolt bracket (3) is sealed to the protective shell (4). The part of the bolt bracket (3) that extends out of the protective shell (4) is a threaded part.

3. The magnetic fixing device for submarine cables according to claim 1, characterized in that, The outer shell (5) is made of TC4 titanium alloy with a thickness of 1-3mm. It has an extremely low corrosion rate in seawater and a dense oxide film can be formed on its surface. The magnet (2) is made of neodymium iron boron permanent magnet with strong magnetic properties and its surface is electroplated with nickel.

4. The magnetic fixing device for submarine cables according to claim 3, characterized in that, The magnet (2) is bonded to the outer shell (5). The magnet (2) is bonded to the bottom of the iron body (1). The exposed part of the iron body (1) is sprayed with Teflon with a thickness of 0.05-0.064mm. The thickness of the bottom step of the outer shell (5) after being coated with glue is between 0.2-0.4mm.

5. The magnetic fixing device for submarine cables according to claim 1, characterized in that, The protective shell (4) is made of a mixture of EPDM and EPDM 4045 rubber. The inner surface of the top cavity of the protective shell (4) is provided with an annular groove with a depth of 0.3-0.8mm and a width of 1-2mm. The annular groove is filled with a buffer adhesive layer to form a mechanical interlocking structure to improve the stability of the interlayer bonding.

6. The magnetic fixing device for submarine cables according to claim 5, characterized in that, The buffer bonding layer uses an epoxy-based elastic adhesive to absorb mechanical stress generated by pressure changes and water flow impact.

7. The magnetic fixing device for submarine cables according to claim 1, characterized in that, The specifications of the magnet (2) and the thickness of the titanium alloy cladding can be freely adjusted according to actual needs, making it suitable for seabed exploration and marine engineering scenarios at different depths.

8. The magnetic fixing device for submarine cables according to claim 1, characterized in that, The opening end of the titanium alloy cladding layer is sealed by a sealing structure, and the bottom groove (6) can be opened on the outer shell (5) as needed to install components and for different usage scenarios.

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