A sensing cable with helical grooves

Abstract

This invention relates to the field of fiber optic sensing cable structure technology, and discloses a sensing submarine cable with a spiral groove, comprising a central reinforcement, a sensitivity-enhancing layer, a sensing optical fiber, a cladding layer, an inner sheath, a reinforcement layer, and an outer sheath. The central reinforcement has an extruded elastomer sensitivity-enhancing layer on its surface, and a spiral groove extending axially on its outer surface. The sensing optical fiber is embedded inside the groove. The cladding layer, inner sheath, reinforcement layer, and outer sheath are sequentially wrapped around the sensitivity-enhancing layer. This invention mechanically amplifies weak acoustic waves and strain signals through the spiral groove on the elastomer sensitivity-enhancing layer, and transmits the signal losslessly to the sensing optical fiber through a surface contact structure, improving underwater sensing sensitivity. The optical fiber is completely housed within the groove, and the sensitivity-enhancing layer bears the overall pressure during construction, preventing damage from impacts. The spiral groove precisely matches the optical fiber and is double-constrained by the cladding layer, preventing fiber misalignment and loosening, ensuring the long-term stability of distributed sensing, and making it suitable for complex marine conditions.

Description

Technical Field

[0001] This invention relates to the field of optical fiber sensing cable structure technology, specifically to a sensing submarine cable with a spiral groove. Background Technology

[0002] In distributed optical fiber sensing systems, the coupling efficiency and positioning accuracy between the sensing fiber and the cable structure directly determine the detection sensitivity, spatial resolution, and long-term measurement stability.

[0003] Existing sensing submarine cables mainly use loose-tube filling grease or conventional tight-tube structures to lay optical fibers, which have obvious defects: the optical fibers are prone to axial slippage and circumferential displacement, and positioning failure occurs under submarine cable bending, tension and long-term marine conditions, which greatly reduces the accuracy of distributed measurement; the contact between the optical fiber and the sheath is insufficient, and the transmission loss of weak external sound waves and strain signals is large, making it difficult to meet the sensing sensitivity requirements of high-precision underwater detection; when multiple sensing optical fibers are laid in parallel, there is no independent constraint structure, and the optical fibers are prone to mutual interference, resulting in poor product process consistency.

[0004] Currently, another type of sensing submarine cable on the market uses a structure where optical fibers are directly spirally wound onto the outer surface of an elastomer-based sensitizing layer. While this structure possesses a certain signal enhancement capability, its drawbacks are significant: the optical fibers are completely exposed on the surface of the sensitizing layer, resulting in poor overall lateral pressure resistance. During engineering construction and deployment, when the submarine cable passes through tire traction equipment, roller compression, and ground compaction, the surface-wound optical fibers are easily compressed, bumped, or damaged, causing breakage and significantly reducing the product's construction tolerance and lifespan.

[0005] Meanwhile, some optical cable structures with spiral grooves have emerged in the industry, but these structures are all used in communication optical cables. The spiral grooves are created on a rigid plastic sheath, and their design purpose is only to improve the bending performance of the optical cable and reduce the installation resistance. The rigid sheath does not have the ability to elastically deform or amplify acoustic signals, and cannot achieve efficient coupling of weak signals. It is completely unsuitable for the application requirements of distributed optical fiber sensing and underwater acoustic detection.

[0006] Therefore, the market urgently needs a sensing submarine cable specifically designed for fiber optic sensing, which combines precise fiber positioning, high strain coupling efficiency, signal enhancement capabilities, and excellent resistance to lateral pressure, and can be adapted to complex construction conditions and harsh marine environments. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a sensing submarine cable with a spiral groove to solve the problems of traditional wound optical fibers being susceptible to lateral pressure differences and breakage, as mentioned in the background section.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a sensing submarine cable with a spiral groove, comprising: The assembly includes a central reinforcing member, a sensitive enhancement layer, a sensing optical fiber, a wrapping layer, an inner sheath, a reinforcing layer, and an outer sheath. The surface of the central reinforcing member is extruded with a sensitive enhancement layer, and the outer surface of the sensitive enhancement layer is provided with a spiral groove that extends spirally along the axial direction of the sensitive enhancement layer. A sensing fiber is disposed inside a spiral groove, the sensing fiber is embedded in the spiral groove, and the surface of the sensitizing layer is covered with a wrapping layer. An inner sheath is disposed on the surface of the wrapping layer. The inner sheath is extruded on the outside of the wrapping layer. A reinforcing layer is installed on the surface of the inner sheath. An outer sheath is extruded on the outside of the reinforcing layer.

[0009] Preferably, the pitch of the spiral grooves is a constant value, determined according to the target measurement signal frequency band and spatial resolution requirements of the sensing system. The spiral grooves are arranged parallel to each other on the outer surface of the sensitivity-enhancing layer, each accommodating multiple sensing optical fibers with different functions.

[0010] Preferably, the cross-section of the spiral groove matches the outer contour of the sensing fiber to form a surface contact, and its radius of curvature or bottom angle parameter is determined according to the outer diameter of the fiber. The spiral groove and the sensitivity enhancement layer are integrally molded, eliminating the need for subsequent secondary trenching processing.

[0011] Preferably, the outer surface of the central reinforcement is provided with a roughened interface structure. When the sensitive enhancement layer is extruded, it is interlocked with the roughened interface structure. The roughened interface structure increases the interfacial bonding area between the central reinforcement and the sensitive enhancement layer, so that the molten material can fully fill the micropores of the roughened structure during the extrusion process, forming a mechanical interlocking effect. This effectively prevents the sensitive enhancement layer from circumferentially slipping or debonding relative to the central reinforcement under long-term bending or stretching conditions, thereby ensuring that the strain on the sensing optical fiber can be truly and completely transmitted to the mechanical response of the central reinforcement, improving the sensing sensitivity and long-term reliability of the entire cable.

[0012] Preferably, an adhesive filling layer is provided between the inner wall of the spiral groove and the sensing optical fiber. The sensing optical fiber is fixedly embedded in the spiral groove by the adhesive filling layer. The adhesive filling layer fills the tiny gap between the inner wall of the spiral groove and the outer surface of the sensing optical fiber, so that a continuous air gap-free coupling interface is formed between the two. This ensures that the strain exerted on the sensitizing layer by the external environment can be uniformly transmitted to the sensing optical fiber through the adhesive filling layer. At the same time, the adhesive filling layer has a certain elastic buffering capacity, which can absorb the local stress fluctuations caused by bending and vibration during the laying and operation of the submarine cable, and avoid micro-bending loss or fatigue fracture of the optical fiber due to stress concentration. The material selection of the adhesive filling layer also needs to take into account the chemical compatibility with the sensitizing layer and the optical fiber coating layer to ensure that aging and debonding do not occur under long-term seawater immersion conditions.

[0013] Preferably, the cladding layer is made of water-blocking wrapping tape wrapped around the outside of the sensitizing layer in an overlapping wrapping manner. The cladding layer completely covers the outer surface of the sensitizing layer and the opening of the spiral groove. The overlapping wrapping method forms an overlap seal between adjacent wrapping tapes, effectively blocking the path of water penetration along the axial direction of the sensitizing layer. After the opening of the spiral groove is completely sealed by the cladding layer, it can prevent seawater from seeping into the groove and causing corrosion to the sensing optical fiber or causing changes in the refractive index of the optical fiber surface. The water-blocking wrapping tape itself has water absorption and expansion characteristics, and can automatically seal the water seepage channel when there is local damage, providing an additional watertight protection barrier for the sensing optical fiber. At the same time, the flexible structure of the cladding layer allows the sensitizing layer to deform normally under stress without constraining the optical fiber in the spiral groove.

[0014] Preferably, the outer surface of the sensing optical fiber is coated with a flexible sensitizing coating, which is in close contact with the inner wall of the spiral groove. The elastic modulus of the flexible sensitizing coating is lower than that of the quartz glass substrate of the sensing optical fiber, and it can preferentially deform under external strain, so as to efficiently transmit the enhanced strain signal to the fiber core and improve the sensitivity to weak signals. The close contact between the coating and the inner wall of the spiral groove ensures the continuity of the strain transmission link and avoids signal attenuation due to the slip surface between the coating and the groove wall. The flexible sensitizing coating also protects the surface coating of the optical fiber from mechanical wear and extends the service life of the sensing optical fiber in the complex stress environment of the submarine cable.

[0015] Preferably, a water-blocking buffer layer is provided between the reinforcing layer and the outer sheath. The water-blocking buffer layer covers the outer surface of the reinforcing layer and forms an intermediate barrier between the reinforcing layer and the outer sheath, which has both water-blocking and buffering functions. When the submarine cable is subjected to external water pressure or external force in the deep sea environment, the water-blocking buffer layer absorbs the impact energy through its compressible deformation, preventing the reinforcing layer from being directly subjected to rigid compression and causing structural damage. At the same time, the material of this layer has excellent water tightness. Even if micro-cracks appear in the outer sheath, the water-blocking buffer layer can effectively slow down the rate of water penetration towards the cable core, providing sufficient emergency protection time for the various functional layers inside the submarine cable.

[0016] Preferably, a lubricating isolation layer is provided between the inner sheath and the reinforcing layer. The lubricating isolation layer covers the outer surface of the inner sheath. The lubricating isolation layer reduces the coefficient of friction between the inner sheath and the reinforcing layer, allowing the layers of the submarine cable to slide relative to each other during bending and laying or dynamic operation. This avoids the additional stress caused by interlayer friction from causing wear or fatigue cracking of the inner sheath and the reinforcing layer. The isolation layer also serves as electrical insulation and chemical isolation, preventing plasticizers and other components in the inner sheath material from migrating to the reinforcing layer and causing deterioration of the reinforcing material's performance. This ensures that the independent function of each structural layer of the submarine cable is not disturbed during long-term service.

[0017] Preferably, the spiral groove has a circular arc or U-shaped cross-section, with a smooth and continuous inner wall that forms a circumferential wrapping surface contact with the outer contour of the sensing fiber. The circular arc cross-section ensures that the inner wall of the spiral groove maintains equidistant contact with the sensing fiber at any cross-section, resulting in an axisymmetric stress distribution. This avoids stress concentration at the corners, which could cause local indentations or microcracks in the fiber coating. The U-shaped cross-section provides a larger groove depth margin, facilitating the embedding and installation of the sensing fiber and subsequent maintenance and replacement. The circumferential wrapping surface contact ensures that the fiber will not shift due to gravity or vibration within the groove, always remaining in the optimal strain coupling position. The smooth and continuous inner wall of the groove also facilitates the uniform coating of the adhesive filling layer, further enhancing the coupling consistency between the fiber and the sensitizing layer.

[0018] Compared with the prior art, the present invention provides a sensing submarine cable with a spiral groove, which has the following advantages: This sensing submarine cable with spiral grooves, by creating the spiral grooves on the surface of the elastomer sensitizing layer, differs from the traditional rigid sheath spiral groove structure of communication optical cables. Leveraging the high elasticity and high acoustic coupling characteristics of the elastomer material, it can mechanically amplify weak sound waves and strain signals, and then transmit the signals losslessly to the sensing optical fiber through a surface contact structure, fundamentally improving the detection sensitivity of underwater sensing and vibration monitoring. Compared to the traditional structure where the sensing optical fiber is directly wound on the surface of the sensitizing layer, this solution completely houses the sensing optical fiber inside the spiral grooves, with the fiber not protruding from the surface of the sensitizing layer. During construction, when the submarine cable passes through conditions such as tire traction machines, roller compression, and ground rolling, the external force is borne by the sensitizing layer as a whole, effectively preventing the sensing optical fiber from being directly subjected to pressure and impact. This completely solves the problem of easy damage and fiber breakage of wound optical fibers, significantly improving construction reliability and product lifespan. The spiral grooves precisely match the sensing optical fibers, and with the double constraint of the outer cladding, the sensing optical fibers will not shift or loosen under conditions such as bending, stretching, and torsion of the submarine cable. This ensures the spatial resolution and measurement stability of distributed sensing even after long-term use. Multiple parallel spiral grooves can independently deploy multiple sensing optical fibers, enabling simultaneous monitoring of multiple parameters such as underwater acoustics, strain, and temperature. The fibers do not interfere with each other, resulting in higher consistency of measurement data. The spiral grooves can be integrally extruded with the sensitizing layer, simplifying the processing and enabling mass production. Simultaneously, the cable body features a rough interlocking interface, an adhesive filling layer, and a multi-layered water-blocking buffer structure. Combined with a central reinforcement, an aramid reinforcement layer, and a seawater-resistant outer sheath, it forms a complete composite protection system, perfectly adapting to the complex and harsh conditions of ocean tides, currents, and deep-sea towing, ensuring stronger long-term service stability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the sensitizing layer of the present invention; Figure 3This is a three-dimensional structural diagram of the sensitizing layer of the present invention; Figure 4 This is a cross-sectional view of the sensitizing layer of the present invention.

[0020] In the diagram: 1. Sensitizing layer; 2. Spiral groove; 3. Central reinforcement; 4. Sensing fiber; 5. Wrapping layer; 6. Inner sheath; 7. Reinforcement layer; 8. Outer sheath. Detailed Implementation

[0021] This invention provides a technical solution: a sensing submarine cable with spiral grooves. Please refer to [link / reference]. Figure 1 It includes a central reinforcing member 3, a sensitivity-enhancing layer 1, a sensing optical fiber 4, a wrapping layer 5, an inner sheath 6, a reinforcing layer 7, and an outer sheath 8. The surface of the central reinforcing member 3 is extruded with the sensitivity-enhancing layer 1. Please refer to [link / reference]. Figure 2 and Figure 3 The outer surface of the sensitizing layer 1 is provided with a spiral groove 2, which extends spirally along the axial direction of the sensitizing layer 1. Please see Figure 1 The sensing fiber 4 is disposed inside the spiral groove 2 and embedded in the spiral groove 2. The surface of the enhancement layer 1 is covered with a wrapping layer 5. Inner sheath 6 is disposed on the surface of wrapping layer 5. Inner sheath 6 is extruded on the outside of wrapping layer 5. Reinforcing layer 7 is installed on the surface of inner sheath 6. Outer sheath 8 is extruded on the outside of reinforcing layer 7.

[0022] Functional differentiation design significantly improves sensing performance This invention features a spiral groove 2 formed on the surface of the elastomer-sensitizing layer 1, which differs from the spiral groove structure of the rigid sheath of traditional communication optical cables. Utilizing the high elasticity and high acoustic coupling characteristics of the elastomer material, weak sound waves and strain signals can be mechanically amplified, and then transmitted losslessly to the sensing optical fiber 4 through a surface contact structure, fundamentally improving the detection sensitivity of underwater sensing and vibration monitoring.

[0023] The embedded structural design provides excellent resistance to lateral pressure and protects the optical fiber. Compared to the traditional structure where the sensing fiber 4 is directly wound around the surface of the sensitizing layer 1, this invention completely houses the sensing fiber 4 inside the spiral groove 2, with the fiber not protruding from the surface of the sensitizing layer 1. During construction, when the submarine cable passes through conditions such as tire traction machines, roller compression, and ground compaction, the external force is borne entirely by the sensitizing layer 1, effectively preventing the sensing fiber 4 from being directly subjected to pressure or impact. This completely solves the problem of easy damage and fiber breakage of wound optical fibers, significantly improving construction reliability and product lifespan.

[0024] Fiber optic positioning is stable and has good measurement consistency. The spiral groove 2 is precisely matched with the sensing fiber 4. With the double constraint of the outer cladding layer 5, the sensing fiber 4 will not shift or loosen under the bending, stretching and twisting conditions of the submarine cable. It can still ensure the spatial resolution and measurement stability of distributed sensing in long-term use.

[0025] Adaptable to signal detection in multiple scenarios The pitch of the spiral groove 2 can be flexibly selected according to different measurement requirements of low frequency and high frequency, and it can be adapted to the monitoring of sound waves and strain signals in different frequency bands. Multiple parallel spiral grooves 2 can be deployed with multiple sensing optical fibers 4 with different functions to realize the synchronous acquisition of multiple parameters such as temperature, vibration, and underwater sound, thus expanding the applicability of the equipment.

[0026] It has strong structural compatibility and is easy to process and manufacture. The spiral groove 2 can be integrally formed by extrusion along with the sensitizing layer 1, or it can be mechanically processed again after the sensitizing layer 1 is formed. The process is simple and has good mass production capability. The overall multi-layer composite structure combined with the central reinforcing component 3, the reinforcing layer 7, and the outer sheath 8 is perfectly adapted to complex working conditions such as ocean tides, ocean currents, and towing, and has a long service life.

[0027] Multiple fibers are deployed independently, with no signal interference. Multiple sensing optical fibers 4 are disposed in independent parallel spiral grooves 2, isolated from each other, and do not interfere with each other during operation, ensuring the accuracy of multi-channel sensing data.

[0028] The pitch of the spiral groove 2 is a constant value, determined according to the target measurement signal frequency band and spatial resolution requirements of the sensing system. The spiral grooves 2 are arranged parallel to each other on the outer surface of the sensitizing layer 1, and each accommodates multiple sensing optical fibers 4 with different functions.

[0029] The cross section of the spiral groove 2 matches the outer contour of the sensing fiber 4 to form a surface contact. Its radius of curvature or bottom angle parameter is determined according to the outer diameter of the fiber. The spiral groove 2 and the sensitive enhancement layer 1 are integrally molded, and no subsequent secondary trenching processing is required.

[0030] The outer surface of the central reinforcement 3 is provided with a roughened interface structure. When the sensitive enhancement layer 1 is extruded, it is interlocked with the roughened interface structure. The roughened interface structure increases the interface bonding area between the central reinforcement 3 and the sensitive enhancement layer 1, so that the molten material can fully fill the micropores of the rough structure during the extrusion process, forming a mechanical interlocking effect. This effectively prevents the sensitive enhancement layer 1 from circumferentially slipping or debonding relative to the central reinforcement 3 under long-term bending or stretching conditions, thereby ensuring that the strain on the sensing optical fiber 4 can be truly and completely transmitted to the mechanical response of the central reinforcement 3, improving the sensing sensitivity and long-term reliability of the entire cable.

[0031] An adhesive filling layer is provided between the inner wall of the spiral groove 2 and the sensing optical fiber 4. The sensing optical fiber 4 is fixedly embedded in the spiral groove 2 through the adhesive filling layer. The adhesive filling layer fills the tiny gap between the inner wall of the spiral groove 2 and the outer surface of the sensing optical fiber 4, so that the two form a continuous air gap-free coupling interface. This ensures that the strain acting on the sensitizing layer 1 can be uniformly transmitted to the sensing optical fiber 4 through the adhesive filling layer. At the same time, the adhesive filling layer has a certain elastic buffering capacity, which can absorb the local stress fluctuations caused by bending and vibration during the laying and operation of the submarine cable, and avoid micro-bending loss or fatigue fracture of the optical fiber due to stress concentration. The material selection of the adhesive filling layer also needs to take into account the chemical compatibility with the sensitizing layer 1 and the optical fiber coating layer to ensure that aging and debonding do not occur under long-term seawater immersion conditions.

[0032] The cladding layer 5 is wrapped around the outside of the sensitizing layer 1 with water-blocking wrapping tape in an overlapping wrapping manner. The cladding layer 5 completely covers the outer surface of the sensitizing layer 1 and the opening of the spiral groove 2. The overlapping wrapping method forms an overlap seal between adjacent wrapping tapes, effectively blocking the path of water penetration along the axial direction of the sensitizing layer 1. After the opening of the spiral groove 2 is completely sealed by the cladding layer 5, it can prevent seawater from seeping into the groove and causing corrosion to the sensing optical fiber 4 or causing changes in the refractive index of the optical fiber surface. The water-blocking wrapping tape itself has water absorption and expansion characteristics, and can automatically seal the water seepage channel when there is local damage, providing an additional watertight protection barrier for the sensing optical fiber 4. At the same time, the flexible structure of the cladding layer 5 allows the sensitizing layer 1 to deform normally under stress without constraining the optical fiber in the spiral groove 2.

[0033] The outer surface of the sensing fiber 4 is coated with a flexible sensitizing coating. The flexible sensitizing coating is in close contact with the inner wall of the spiral groove 2. The elastic modulus of the flexible sensitizing coating is lower than that of the quartz glass substrate of the sensing fiber 4. It can preferentially deform under external strain, and efficiently transmit the enhanced strain signal to the fiber core, thereby improving the sensitivity to weak signals. The close contact between the coating and the inner wall of the spiral groove 2 ensures the continuity of the strain transmission link and avoids signal attenuation due to the slip surface between the coating and the groove wall. The flexible sensitizing coating also protects the surface coating of the fiber from mechanical wear and extends the service life of the sensing fiber 4 in the complex stress environment of the submarine cable.

[0034] A water-blocking buffer layer is provided between the reinforcing layer 7 and the outer sheath 8. The water-blocking buffer layer covers the outer surface of the reinforcing layer 7 and forms an intermediate barrier between the reinforcing layer 7 and the outer sheath 8, which has both water-blocking and buffering functions. When the submarine cable is subjected to external water pressure or external force in the deep sea environment, the water-blocking buffer layer absorbs the impact energy through its compressible deformation, preventing the reinforcing layer 7 from being directly subjected to rigid compression and causing structural damage. At the same time, the material of this layer has excellent water tightness. Even if micro-cracks appear in the outer sheath 8, the water-blocking buffer layer can effectively slow down the rate of water penetration towards the cable core, providing sufficient emergency protection time for the various functional layers inside the submarine cable.

[0035] A lubricating isolation layer is provided between the inner sheath 6 and the reinforcing layer 7. The lubricating isolation layer covers the outer surface of the inner sheath 6. The lubricating isolation layer reduces the coefficient of friction between the inner sheath 6 and the reinforcing layer 7, allowing the layers to slide relative to each other during bending and laying or dynamic operation of the submarine cable. This prevents the additional stress generated by interlayer friction from causing wear or fatigue cracking of the inner sheath 6 and the reinforcing layer 7. The isolation layer also serves as an electrical insulation and chemical isolation layer, preventing plasticizers and other components in the inner sheath 6 material from migrating to the reinforcing layer 7 and causing deterioration of the reinforcing material's performance. This ensures that the independent function of each structural layer of the submarine cable is not disturbed during long-term service.

[0036] Please see Figure 4 The spiral groove 2 has a circular arc or U-shaped cross-section and a smooth, continuous inner wall, forming a circumferential wrapping surface contact with the outer contour of the sensing fiber 4. The circular arc cross-section ensures that the inner wall of the spiral groove 2 maintains equidistant contact with the sensing fiber 4 on any cross-section, and the stress distribution is axially symmetrical, avoiding stress concentration at the corners that could cause local indentations or microcracks in the fiber coating. The U-shaped cross-section provides a larger groove depth margin, facilitating the embedding and installation of the sensing fiber 4 and subsequent maintenance and replacement. The circumferential wrapping surface contact ensures that the fiber will not shift due to gravity or vibration within the groove and will always be in the optimal strain coupling position. The smoothness of the inner wall of the groove also facilitates the uniform coating of the adhesive filling layer, further improving the coupling consistency between the fiber and the sensitizing layer 1.

[0037] In this design, the central reinforcement 3 is made of KFRP composite rod, which is lightweight and has high tensile strength, and can partially resist tensile and bending loads in marine environments.

[0038] The sensitizing layer 1 is made of polyurethane elastomer with high damping and high acoustic coupling efficiency, extruded and integrally extruded on the outside of the central reinforcement 3. The outer surface of the sensitizing layer 1 is integrally extruded with three parallel spiral grooves 2, which extend spirally with equal pitch along the axial direction.

[0039] Each spiral groove 2 contains a single embedded sensing fiber 4. The cross-section of the spiral groove 2 can be arc-shaped, perfectly matching the outer circular contour of the sensing fiber 4. After embedding, the fiber is in full-area contact with the inner wall of the groove. The groove depth is slightly larger than the outer diameter of the sensing fiber 4, with no protruding structures. This embedded structure can effectively resist lateral pressure and extrusion during construction, preventing damage to the fiber.

[0040] This embodiment is applied to the marine low-frequency underwater acoustic monitoring scenario. Therefore, the spiral groove 2 adopts a small pitch design to increase the number of optical fiber windings per unit length, thereby improving the sampling density and detection accuracy of low-frequency signals.

[0041] The sensitive enhancement layer 1 and the outer sensing optical fiber 4 are covered with a non-woven fabric wrapping layer 5. The wrapping layer 5 is tightly wound to fix the optical fiber in the spiral groove 2 without slippage.

[0042] The outer side of the outer sheath 5 is extruded into an inner sheath 6, which is made of conventional polyolefin material to achieve overall sealing and buffer against external instantaneous mechanical impact.

[0043] The inner sheath 6 is provided with an outer reinforcing layer 7 formed by aramid fiber weaving. The aramid fiber has ultra-high tensile and shear strength, which meets the strength requirements of deep-sea cable towing and stretching.

[0044] The outermost layer is a polyolefin outer sheath 8 that is resistant to seawater and biofouling, which isolates it from seawater, marine life and external friction damage.

[0045] In this embodiment, the three sensing optical fibers 4 can be used for underwater acoustic detection, strain monitoring, and temperature monitoring, respectively, to achieve simultaneous measurement of multiple parameters of the marine environment. After the overall structure is protected by multiple layers, it can operate stably in deep sea, near-sea and other scenarios for a long time. At the same time, it can adapt to conventional construction methods such as tire traction and roller conveying. The optical fibers are not easily damaged by compression.

[0046] During processing, the spiral groove 2 is integrally formed during the extrusion of the sensitive layer 1 using a self-developed special extrusion equipment, eliminating the need for subsequent secondary grooving processing, making it suitable for mass production.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sensing submarine cable with spiral grooves, characterized in that, include: The central reinforcing member (3), the sensitive enhancement layer (1), the sensing fiber (4), the wrapping layer (5), the inner sheath (6), the reinforcing layer (7) and the outer sheath (8) are provided. The surface of the central reinforcing member (3) is extruded with the sensitive enhancement layer (1). The outer surface of the sensitive enhancement layer (1) is provided with a spiral groove (2). The spiral groove (2) extends in a spiral manner along the axial direction of the sensitive enhancement layer (1). The sensing fiber (4) is disposed inside the spiral groove (2), the sensing fiber (4) is embedded in the spiral groove (2), and the surface of the sensitivity enhancement layer (1) is covered with a wrapping layer (5). An inner sheath (6) is disposed on the surface of the wrapping layer (5). The inner sheath (6) is extruded on the outside of the wrapping layer (5). A reinforcing layer (7) is installed on the surface of the inner sheath (6). An outer sheath (8) is extruded on the outside of the reinforcing layer (7).

2. The sensing submarine cable with spiral grooves according to claim 1, characterized in that: The pitch of the spiral groove (2) is a constant value, and the spiral groove (2) is arranged parallel to each other on the outer surface of the sensitizing layer (1).

3. The sensing submarine cable with spiral grooves according to claim 1, characterized in that: The cross section of the spiral groove (2) matches the outer contour of the sensing fiber (4) to form a surface contact, and the spiral groove (2) and the sensitivity enhancement layer (1) are integrally molded.

4. A sensing submarine cable with spiral grooves according to claim 1, characterized in that: The outer surface of the central reinforcing member (3) is provided with a roughened interface structure, and the sensitive layer (1) is interlocked with the roughened interface structure during extrusion molding.

5. A sensing submarine cable with a spiral groove according to claim 1, characterized in that: An adhesive filling layer is provided between the inner wall of the spiral groove (2) and the sensing optical fiber (4), and the sensing optical fiber (4) is fixedly embedded in the spiral groove (2) by the adhesive filling layer.

6. A sensing submarine cable with a spiral groove according to claim 1, characterized in that: The wrapping layer (5) is wrapped around the outside of the sensitizing layer (1) with water-blocking wrapping tape in an overlapping wrapping manner. The wrapping layer (5) completely covers the outer surface of the sensitizing layer (1) and the groove of the spiral groove (2).

7. A sensing submarine cable with a spiral groove according to claim 1, characterized in that: The outer surface of the sensing fiber (4) is coated with a flexible sensitizing coating, which is in close contact with the inner wall of the spiral groove (2).

8. A sensing submarine cable with a spiral groove according to claim 1, characterized in that: A water-blocking buffer layer is provided between the reinforcing layer (7) and the outer sheath (8), and the water-blocking buffer layer covers the outer surface of the reinforcing layer (7).

9. A sensing submarine cable with a spiral groove according to claim 1, characterized in that: A lubricating isolation layer is provided between the inner sheath (6) and the reinforcing layer (7), and the lubricating isolation layer covers the outer surface of the inner sheath (6).

10. A sensing submarine cable with a spiral groove according to claim 1, characterized in that: The cross-section of the spiral groove (2) is arc-shaped or U-shaped, and the inner wall of the groove is continuous and smooth, forming a circumferential wrapping surface contact with the outer contour of the sensing fiber (4).

Images