Diagnosis type monitoring cable for cabin segmentation limit self-sealing and cabin section coding and preparation method thereof

Abstract

The application relates to a monitoring cable with cabin-limiting self-sealing and cabin-section coding diagnosis and a preparation method thereof, and belongs to the technical field of water conservancy and hydropower engineering monitoring cables. The cable core is sequentially provided with an inner water-resisting wrapping layer, a composite shielding layer, a cabin-limiting self-sealing layer, a cabin-section coding diagnosis layer and a gradient sheath layer. The cabin-limiting self-sealing layer comprises annular partition ribs arranged at intervals along the length direction of the cable, a limited sealing cabin is formed between adjacent partition ribs, a water pressure driven flange check valve, a trigger release cavity and a reaction sealing material are arranged in the cabin. The cabin-section coding diagnosis layer is provided with coding impedance units with different impedance characteristics at the corresponding positions of each limited sealing cabin. The embedded sheath layer of the gradient sheath layer is embedded in the outer side of the partition rib, the surface of the diagnosis layer and the micro-gap of the braided layer under extrusion pressure, and a mechanical interlocking sealing boundary is formed. The application realizes cabin-limiting, mechanical check, in-situ sealing and cabin positioning in a high water pressure immersion environment, and is suitable for long-term monitoring cables of water conservancy and hydropower engineering.

Description

Technical Field

[0001] This invention belongs to the field of monitoring cable technology for water conservancy and hydropower projects, specifically relating to a compartmentalized, self-sealing, and compartment-coded diagnostic type water conservancy and hydropower project toughness monitoring cable suitable for dams, dam foundations, corridors, slopes, soil and rock masses, groundwater environments, and long-term humid and immersive environments, as well as its preparation method. Background Technology

[0002] Safety monitoring systems for water conservancy and hydropower projects typically utilize monitoring instruments such as piezometers, strain gauges, displacement gauges, crack gauges, and thermometers to collect signals indicating the project's operational status. These instruments are then connected to data acquisition devices via monitoring cables. These monitoring cables are frequently laid within dam concrete, dam foundations, galleries, slopes, soil and rock masses, and in groundwater environments, enduring long-term combined effects of immersion, water pressure, temperature cycling, alkaline concrete media, acidic groundwater, mechanical compression, and electromagnetic interference.

[0003] Existing monitoring cables for water conservancy and hydropower projects mostly adopt a conventional structure with polyethylene insulation, aluminum-plastic composite tape or copper wire braided shielding, and soft PVC sheath. While this structure meets general electrical insulation and mechanical protection requirements, it still presents the following problems in long-term high-pressure immersion environments: First, moisture easily spreads longitudinally along the cable core gaps, wrapping overlaps, the interface between the shielding layer and the sheath layer, and micro-cracks in the sheath; Second, conventional water-blocking tapes or yarns rely heavily on water-absorbing and expanding materials to fill the channels, which can easily lead to localized erosion, expansion stress concentration, or repeated failures under continuous high water pressure; Third, conventional self-healing materials are mostly designed for sheath cracks or polymer matrix cracks, and are difficult to reliably seal the longitudinal seepage channels within the cable's internal interface; Fourth, although ordinary leak detection cables can detect moisture, they cannot simultaneously block the water path, and they typically determine the presence of water ingress based on overall conductivity, failing to establish a one-to-one compartment-level positioning relationship with the monitoring cable's own water-blocking structure.

[0004] In existing cable material technologies, common improvement directions mainly focus on adjusting the formulation of polyethylene insulation or polyvinyl chloride sheathing materials. Essentially, this is still a passive improvement of the material formulation in terms of water resistance, cold resistance, or corrosion resistance, and it is difficult to solve the problem that once micro-seepage occurs at the interface under high water pressure, it spreads along the length direction.

[0005] Therefore, there is an urgent need for a toughness monitoring cable for water conservancy and hydropower projects that breaks away from the conventional approach of improving material formulations. This cable would have its internal seepage channels pre-divided into multiple confined compartments. In the event of localized water ingress, the water pressure itself would drive mechanical check valves and in-situ sealing. Furthermore, the location of the water ingress would be identified through a coded diagnostic structure that corresponds one-to-one with each compartment, thereby improving the reliability of the cable under long-term high-pressure immersion conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a compartment-limited self-sealing and compartment-coded diagnostic monitoring cable and its preparation method. Under the long-term high water pressure immersion environment of monitoring cables in water conservancy and hydropower projects, the longitudinal water seepage channel formed by the interface of the sheath, shield and wrapping is limited to a local compartment, and mechanical check valve, in-situ sealing and compartment-level positioning are achieved simultaneously in the early stage of local water ingress.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a compartment-limited self-sealing and compartment-encoded diagnostic monitoring cable, comprising a cable core formed by twisting together multiple insulated wire cores and a protective layer disposed outside the cable core; The protective layer, from the inside out, includes an inner water-blocking wrapping layer, a composite shielding layer, a compartment-specific self-sealing layer, a compartment coding diagnostic layer, and a gradient sheath layer. The compartmentalized self-sealing layer includes multiple circumferential isolation ribs spaced apart along the cable length, a confinement sealing chamber located between adjacent circumferential isolation ribs, and a water pressure driven flange check plate, a trigger release chamber, and reactive sealing material disposed within the confinement sealing chamber; the circumferential isolation ribs extend along the circumference of the cable and form a press-fit or fusion seal with the outer surface of the composite shielding layer and the inner surface of the gradient sheath layer; The compartment coding diagnostic layer includes a common detection conductor, segment detection conductors, and multiple coding impedance units extending along the cable length direction; each of the confined sealing compartments is provided with at least one coding impedance unit, connected between the common detection conductor and the segment detection conductor; the impedance characteristics of the coding impedance units corresponding to different confined sealing compartments are different; the coding impedance unit is covered with a water-conductive layer or a water-dielectric-changing layer. The gradient sheath layer includes an inner embedded sheath layer covering the compartment coding diagnostic layer and an outer weather-resistant sheath layer covering the inner embedded sheath layer; the inner embedded sheath layer is simultaneously embedded in the micro gaps of the outer side of the circumferential partition rib, the outer surface of the compartment coding diagnostic layer and the composite shielding layer under extrusion pressure, forming a mechanical interlocking structure with the circumferential partition rib.

[0008] Furthermore, the composite shielding layer includes a metal composite strip wrapped around the inner water-blocking wrapping layer and a metal braided layer disposed outside the metal composite strip, wherein the metal surface of the metal composite strip faces outward and is in direct contact with the metal braided layer.

[0009] Furthermore, the circumferential partition rib is made of one or more of thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, hydrogenated styrene elastomer, silicone rubber, or polyvinyl chloride elastic composite material. The peel strength between the circumferential partition rib and the outer surface of the composite shielding layer is not less than 1.0 N / mm. The axial distance between adjacent circumferential partition ribs is 80 mm to 800 mm, the height of the circumferential partition rib is 0.15 mm to 0.80 mm, and the width is 1 mm to 8 mm.

[0010] Furthermore, the water pressure driven flange check plate includes a fixed root and a free flange; the fixed root is fixed to the circumferential partition rib or the outer surface of the composite shielding layer, and the free flange is inclined towards the seepage direction, forming an initial angle of 15° to 75° with the outer surface of the composite shielding layer; when water enters the confined sealing chamber under water pressure, the water pressure pushes the free flange to fit against the adjacent interface, forming a check seal interface.

[0011] Furthermore, the trigger release chamber is formed by one or more of the following: a fracturing thin-walled structure, a swelling thin-walled structure, or a hydrolyzable thin-walled structure; the reactive plugging material includes a first plugging component and a second plugging component, which are stored separately within the trigger release chamber or are respectively disposed in different trigger release chambers within the same confined plugging chamber; the first plugging component is one or more of the following: silane-terminated polyether, silane-terminated polyurethane, isocyanate-terminated polyurethane prepolymer, or epoxy-modified silane prepolymer; the second plugging component is one or more of the following: water-absorbing and swelling particles, moisture-curing catalyst, alkaline water stabilizer, sheet-like barrier filler, or fiber-reinforced filler.

[0012] Furthermore, the resistance value, RC time constant, or LC resonant frequency of the coded impedance unit is arranged in binary, arithmetic, or geometric sequence; the water ingress response time of the water-conducting layer or water-dielectric-changing layer is no greater than 5 minutes. An insulating isolation section is provided between adjacent coded impedance units, and the insulating isolation section corresponds to the axial position of the circumferential partition rib.

[0013] Furthermore, the inner water-resistant cladding layer, the metal composite strip, the compartment-limited self-sealing layer, and the compartment coding diagnostic layer all have overlapping seams, and the circumferential misalignment angle of the overlapping seams of adjacent layers is 30° to 150°; the circumferential partition ribs are arranged on both sides of the axial direction of the non-overlapping area of ​​the overlapping seam or the staggered area of ​​the overlapping seam.

[0014] Furthermore, the Shore A hardness of the inner sheath layer is 5 to 25 lower than that of the outer weathering sheath layer, and the thickness of the inner sheath layer accounts for 20% to 55% of the total thickness of the gradient sheath layer; the total thickness of the gradient sheath layer is not less than 1.2 mm.

[0015] This invention further proposes a compartmentalized self-sealing layer for use in resilience monitoring cables in water conservancy and hydropower projects. The compartmentalized self-sealing layer includes multiple circumferential partition ribs spaced along the cable length, a confinement sealing chamber located between adjacent circumferential partition ribs, a water-pressure driven flap check valve disposed within the confinement sealing chamber, a trigger release chamber, and a reactive sealing material. The circumferential partition ribs are made of one or more of thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, hydrogenated styrene elastomers, silicone rubber, or polyvinyl chloride elastic composites, with a peel strength of not less than 1.0 N / mm between them and adjacent structural layers. The water-pressure driven flap check valve includes a fixed root and a free flap portion. When moisture enters the confinement sealing chamber, the water pressure pushes the free flap portion to adhere to the adjacent interface to form a check valve sealing interface, triggering the release chamber to release the reactive sealing material. The reactive sealing material forms a confinement elastic sealing body within the confinement sealing chamber.

[0016] This invention further proposes a method for preparing the above-mentioned compartment-limited self-sealing and compartment-coded diagnostic monitoring cable, comprising the following steps: S1 is made by stranding tin-plated soft round copper wires to form a conductor, and then extruding insulating material on the outside of the conductor to form an insulating layer, thus obtaining an insulated wire core; S2, multiple insulated wire cores are twisted together to form a cable core, non-hygroscopic elastic filler rope is filled between the insulated wire cores, and an inner water-blocking wrapping layer is formed by wrapping the cable core. S3, wrap a metal composite strip around the inner water-blocking wrapping layer with the metal side facing outward, and then braid tin-plated copper wire to form a metal braided layer to obtain a composite shielding layer; S4, using intermittent molding, intermittent extrusion, hot pressing or laser welding, forms multiple circumferential partition ribs at intervals along the cable length direction outside the composite shielding layer. These ribs are made of one or more of thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, hydrogenated styrene elastomers, silicone rubber or polyvinyl chloride elastic composite materials, so that the peel strength between the S4 and the composite shielding layer is not less than 1.0 N / mm. S5, water pressure driven flange check plate, trigger release chamber and reactive sealing material are arranged between adjacent circumferential partition ribs to form a confined sealing chamber and thus obtain a compartmentalized confined self-sealing layer; S6, outside the compartmentalized self-sealing layer, a common detection conductor, segmented detection conductor and multiple coded impedance units are set up so that each compartmentalized self-sealing compartment corresponds to at least one coded impedance unit, forming a compartmentalized coded diagnostic layer; S7 uses co-extrusion or step-extrusion to form a gradient sheath layer. The inner sheath layer is extruded using an extrusion die. During extrusion, the melt pressure causes the inner sheath layer material to simultaneously enter the micro gaps on the outer side of the circumferential partition rib, the micro gaps on the outer surface of the compartment coding diagnostic layer, and the micro gaps of the metal braid layer, and form an outer weather-resistant sheath layer outside the inner sheath layer. S8, the common detection conductor and the segmented detection conductor are led out at the cable end and encapsulated to form a detection end.

[0017] Compared with the prior art, the present invention has the following beneficial effects: First, the present invention divides the longitudinal water channel interface inside the cable into multiple confined sealing compartments by using circumferential partition ribs, so that local water ingress is restricted to the corresponding compartment and cannot spread continuously along the length of the cable.

[0018] Secondly, in this invention, the flanged check sheet is driven by water pressure to form a mechanical check seal interface, which is connected with the sequential opening of the three types of thin-walled materials: crackable, swellable, and hydrolyzable. This allows the release and solidification of the reactive sealing material to be completed gradually after the check interface stabilizes, preventing the sealing material from being washed away and diffused by the water flow before the check interface is established.

[0019] Third, in this invention, the encoded impedance unit corresponds one-to-one with the confined sealing chamber, and the position of the insulating isolation section corresponds to the position of the circumferential partition rib, so that the detection boundary is consistent with the sealing boundary, the water ingress response time is no more than 5 minutes, and it can identify the specific water ingress chamber section rather than just determine whether there is water ingress.

[0020] Fourth, in this invention, the embedded sheath layer is simultaneously embedded into the outer side of the circumferential partition rib, the outer surface of the diagnostic layer, and the micro-gap of the braided layer under extrusion pressure, forming a mechanical interlock and enhancing the sealing stability of the compartment boundary. Simultaneously, the metal composite strip, with its metal surface facing outward, directly contacts the metal braided layer, eliminating the need for a drain wire structure and utilizing the braided layer for direct grounding. This results in a larger contact area, higher grounding reliability, and a simpler structure.

[0021] Fifth, in this invention, compartmentalized confinement, orderly mechanical check valve, three-stage in-situ sealing, compartment coding diagnosis, and gradient-fitting sheath work together to form a collaborative system around the same confinement sealing compartment. This system can achieve high-pressure confinement sealing and compartment positioning effects that are difficult to obtain with conventional water-blocking strips, ordinary self-healing materials, or ordinary leak detection cables. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the radial cross-sectional structure of the monitoring cable of the present invention.

[0023] Figure 2 This is a partial cross-sectional schematic diagram of the compartmentalized self-sealing layer of the present invention along the length of the cable.

[0024] Figure 3 This is a schematic diagram of the operation of the water pressure driven flange check plate of the present invention before and after water intake.

[0025] Figure 4 This is a schematic diagram illustrating the coding detection principle of the compartment coding diagnostic layer of the present invention.

[0026] Figure 5This is a schematic diagram of the preparation method of the present invention.

[0027] The markings in the diagram are: 1. Conductor; 2. Insulation layer; 3. Non-hygroscopic elastic filler rope; 4. Inner water-resistant wrapping layer; 5. Metal composite strip; 6. Metal braided layer; 7. Compartmentalized self-sealing layer; 71. Circumferential partition rib; 72. Compartmentalized sealing chamber; 73. Water pressure driven flange check plate; 731. Fixed root; 732. Free flange; 74. Trigger release chamber; 75. Reactive sealing material; 76. Compartmentalized elastic sealing body; 8. Compartment coding diagnostic layer; 81. Common detection conductor; 82. Segmented detection conductor; 83. Coding impedance unit; 84. Water-conducting layer; 85. Insulating isolation section; 9. Inner embedded sheath layer; 10. Outer weather-resistant sheath layer; 11. Detection end. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the invention in any way.

[0029] See attached document Figure 1 As shown, a compartment-limited self-sealing and compartment-coded diagnostic monitoring cable includes a cable core formed by stranding multiple insulated wire cores and a protective layer disposed outside the cable core.

[0030] The following is in conjunction with the appendix Figure 1-4 A detailed description of the cable's specific structure.

[0031] The insulated core includes a conductor 1 and an insulating layer 2 covering the conductor 1. The conductor 1 is formed by stranding tin-plated soft round copper wire with a nominal cross-sectional area of ​​0.22 mm². 2 0.35mm 2 0.75mm 2 Or 1.5mm 2 The insulation layer 2 is formed by extrusion of polyethylene-based insulating material, with a nominal thickness of 0.4 mm to 0.6 mm. The internal gaps of the cable core are filled with non-hygroscopic elastic filler rope 3, which is polypropylene foam rope, ethylene-propylene elastomer filler rope, or silicone rubber hollow filler strip.

[0032] The protective layer, from the inside out, includes an inner water-blocking wrapping layer 4, a composite shielding layer, a compartment-specific self-sealing layer 7, a compartment coding and diagnostic layer 8, and a gradient sheath layer. The inner water-blocking wrapping layer 4 is formed by wrapping polyester tape, polypropylene tape, non-hygroscopic water-blocking tape, or semi-conductive water-blocking tape, with a wrapping overlap rate of 10% to 25%.

[0033] The composite shielding layer includes a metal composite strip 5 and a metal braided layer 6. The metal composite strip 5 is an aluminum-plastic composite strip, a copper-plastic composite strip, or an aluminum-magnesium alloy-plastic composite strip, with the metal side facing outwards and a wrapping overlap rate of 15% to 30%. The metal braided layer 6 is formed by braiding tin-plated copper wire with a diameter of 0.10 mm to 0.18 mm and a braiding density of 80% to 92%. The metal side of the metal composite strip 5 faces outwards and is in direct contact with the metal braided layer 6, which serves as the grounding conductor structure.

[0034] The compartmentalized self-sealing layer 7 is disposed outside the composite shielding layer, including multiple circumferential isolation ribs 71 spaced apart along the cable length direction, a compartmentalized sealing chamber 72 located between adjacent circumferential isolation ribs 71, and a water pressure driven flange check plate 73, a trigger release chamber 74 and a reactive sealing material 75 disposed in the compartmentalized sealing chamber 72.

[0035] The circumferential partition rib 71 is made of one or more of thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, hydrogenated styrene elastomer, silicone rubber, or polyvinyl chloride elastic composite material. It has low melt viscosity and good interfacial wettability, allowing it to fully adhere to the outer surface of the metal braid layer 6 during molding and maintain elasticity over a wide temperature range. The peel strength between it and the composite shielding layer is not less than 1.0 N / mm. The circumferential partition rib 71 extends along the circumference of the cable and forms a press-fit or fusion-fit seal with the outer surface of the composite shielding layer and the inner surface of the gradient sheath layer. The axial distance between adjacent circumferential partition ribs 71 is 80 mm to 800 mm, preferably 120 mm to 300 mm. The height of the circumferential partition rib 71 is 0.15 mm to 0.80 mm, and the width is 1 mm to 8 mm.

[0036] The confined sealing chamber 72 is a local space enclosed by adjacent circumferential partition ribs 71, the outer surface of the composite shielding layer, and the inner surface of the gradient sheath layer. Each confined sealing chamber 72 contains at least one water-pressure driven flanged check valve 73, including a fixed root 731 and a free flanged portion 732. The fixed root 731 is fixed to the circumferential partition rib 71 or the outer surface of the composite shielding layer, while the free flanged portion 732 is inclined towards the direction of potential water seepage, forming an initial angle of 15° to 75° with the outer surface of the composite shielding layer. When water enters the confined sealing chamber 72 under water pressure, the water pressure pushes the free flanged portion 732 to adhere to the outer surface of the composite shielding layer or the inner surface of the gradient sheath layer, forming a check valve sealing interface.

[0037] The trigger release chamber 74 is located within the confined sealing chamber 72 and is formed by one or more of the following: a fracturing thin-walled structure, a swellable thin-walled structure, or a hydrolyzable thin-walled structure, encapsulating a reactive sealing material 75 within it. When moisture enters the confined sealing chamber 72, the fracturing thin-walled structure ruptures first when the water pressure reaches a set threshold (preferably 0.3 MPa to 0.5 MPa), its opening moment being essentially synchronized with the check valve action of the water-driven flap check valve 73. The swellable thin-walled structure subsequently deforms and opens due to water absorption and expansion, its opening moment lagging behind that of the fracturing thin-walled structure. The hydrolyzable thin-walled structure gradually degrades and opens under continuous water immersion, its opening moment lagging behind that of the swellable thin-walled structure. The three structures sequentially release the reactive sealing material 75, which mixes and solidifies within the confined sealing chamber 72, forming a confined elastic sealing body 76 constrained by circumferential partition ribs 71.

[0038] The reactive plugging material 75 includes a first plugging component and a second plugging component, which are stored separately in the trigger release chamber 74 or respectively disposed in different trigger release chambers 74 within the same confined plugging chamber 72. The first plugging component is one or more of silane-terminated polyether, silane-terminated polyurethane, isocyanate-terminated polyurethane prepolymer, or epoxy-modified silane prepolymer; the second plugging component is one or more of water-absorbing and swelling particles, moisture-curing catalyst, alkaline water stabilizer, sheet-like barrier filler, or fiber-reinforced filler. The water-absorbing and swelling particles are one or more of cross-linked polyacrylate, grafted starch-acrylate, bentonite-polyacrylate composite particles, or polyacrylamide-acrylate copolymer particles, with a particle size D50 of 20μm to 180μm; the sheet-like barrier filler is one or more of sheet-like mica powder, sheet-like talc powder, graphene micro flakes, layered double hydroxide, or modified montmorillonite; the fiber-reinforced filler is one or more of aramid short fibers, polyester short fibers, basalt short fibers, or glass short fibers, with a length of 0.1mm to 3mm.

[0039] The compartment coding diagnostic layer 8 is located outside the compartment-limited self-sealing layer 7 and includes a common detection conductor 81 extending along the cable length, segment detection conductors 82, and multiple coding impedance units 83. Each compartment-limited sealing compartment 72 is provided with at least one coding impedance unit 83, connected between the common detection conductor 81 and the segment detection conductors 82; the resistance value, RC time constant, or LC resonant frequency of the coding impedance units 83 corresponding to different compartment-limited sealing compartments 72 are different and are arranged according to binary, arithmetic sequence, geometric sequence, or other preset rules. The coding impedance unit 83 is covered with a water-conductive layer 84 or a water-dielectric-changing layer, and the impedance characteristics of the coding impedance unit change identibly within 5 minutes after the corresponding compartment is flooded. The detection end 11 determines the location of the flooded compartment by measuring the resistance, capacitance, impedance spectrum, or time-domain reflection signal between the common detection conductor 81 and the segment detection conductors 82. An insulating isolation section 85 is provided between adjacent coding impedance units 83, corresponding to the axial position of the circumferential isolation rib 71.

[0040] The internal water-blocking cladding layer 4, the metal composite strip 5, the compartment-limited self-sealing layer 7, and the compartment coding diagnostic layer 8 all have overlapping seams. The circumferential misalignment angle of the overlapping seams of adjacent layers is 30° to 150°, preferably 60° to 120°. The circumferential partition ribs 71 are preferably set on both sides of the axial direction of the non-overlapping area of ​​the overlapping seam or the staggered area of ​​the overlapping seam.

[0041] The gradient sheath layer comprises an inner embedded sheath layer 9 and an outer weather-resistant sheath layer 10. The inner embedded sheath layer 9 is formed by extrusion of flexible PVC sheath material, thermoplastic polyurethane-modified PVC sheath material, or ethylene-vinyl acetate blended PVC sheath material. The extrusion temperature is 145℃ to 170℃, and the die pressure is 8MPa to 20MPa. The melt simultaneously enters the micro-gap between the outer side of the circumferential partition rib 71, the outer surface of the compartment coding diagnostic layer 8, and the metal braid layer 6. After cooling and solidification, it forms a mechanical interlock with the circumferential partition rib 71, providing radial and axial clamping constraints on the partition rib and enhancing the interfacial bonding between the sheath and the composite shielding layer. The outer weather-resistant sheath layer 10 is formed by extrusion of acid- and alkali-resistant and UV-resistant PVC sheath material. The Shore A hardness of the inner sheath layer 9 is 5 to 25 lower than that of the outer weather-resistant sheath layer 10, and its thickness accounts for 20% to 55% of the total thickness of the gradient sheath layer; the total thickness of the gradient sheath layer is not less than 1.2 mm, and the nominal thickness is determined according to δ=0.035D+0.8 mm, where D is the front diameter of the sheath.

[0042] The raw materials of the outer weather-resistant sheath layer 10, by weight, include: 100 parts of polyvinyl chloride resin, 10 to 25 parts of trioctyl trimellitate, 8 to 20 parts of one or more of polybutylene adipate, polyethylene adipate, or dioctyl terephthalate, 5 to 15 parts of one or more of dioctyl adipate, diisononyl adipate, or didecyl adipate, 5 to 15 parts of chlorinated polyethylene, 3 to 12 parts of thermoplastic polyurethane, 8 to 20 parts of surface-treated nano-calcium carbonate, 0.5 to 3 parts of hydrophobic silica, 2 to 8 parts of flake mica powder, 4 to 8 parts of calcium-zinc composite heat stabilizer, and bis(2,2,6) 0.2 to 1.2 parts of one or both of the following: 6-tetramethyl-4-piperidinyl) sebacate or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate; 0.2 to 1.0 parts of one or both of the following: 2-hydroxy-4-n-octyloxybenzophenone or 2-(2-hydroxy-5-methylphenyl)benzotriazole; 0.2 to 1.0 parts of one or both of the following: tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester or tris(2,4-di-tert-butylphenyl) phosphite; and 0.2 to 1.0 parts of one or both of the following: stearic acid or calcium stearate.

[0043] like Figure 5 As shown, the method for preparing the monitoring cable described above includes the following steps: S1, conductor 1 is formed by stranding tin-plated soft round copper wire, and polyethylene-based insulating material is extruded on the outside of conductor 1 to form an insulating layer 2, thus obtaining an insulated wire core; S2, multiple insulated wire cores are twisted together to form a cable core, non-hygroscopic elastic filler rope 3 is filled between the insulated wire cores, and an inner water-blocking wrapping layer 4 is formed by wrapping around the outside of the cable core. S3, a metal composite strip 5 is wrapped around the inner water-blocking wrapping layer 4 with the metal side facing outward and in contact with the metal braided layer to obtain a composite shielding layer, wherein the metal braided layer 6 is formed by braiding tin-plated copper wire. S4, using intermittent molding, intermittent extrusion, hot pressing or laser welding, forms multiple circumferential partition ribs 71 at intervals along the cable length direction outside the composite shielding layer. These ribs are made of one or more of thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, hydrogenated styrene elastomers, silicone rubber or polyvinyl chloride elastic composite materials, so that the peel strength between the ribs and the composite shielding layer is not less than 1.0 N / mm. S5, a water pressure driven flange check plate 73, a trigger release chamber 74 and a reactive sealing material 75 are arranged between adjacent circumferential partition ribs 71 to form a confined sealing chamber 72, thereby obtaining a compartmentalized confined self-sealing layer 7. S6, a common detection conductor 81, a segmented detection conductor 82 and multiple coded impedance units 83 are set outside the compartmentalized self-sealing layer 7, so that each compartmentalized self-sealing compartment 72 corresponds to at least one coded impedance unit 83, forming a compartmentalized coded diagnostic layer 8. S7, a gradient sheath layer is formed by co-extrusion or step extrusion. The inner sheath layer 9 is extruded by extrusion die with an extrusion temperature of 145°C to 170°C and a die head pressure of 8MPa to 20MPa. This allows the sheath material to simultaneously enter the micro gaps on the outer side of the circumferential partition rib 71, the micro gaps on the outer surface of the compartment coding diagnostic layer 8, and the micro gaps of the metal braided layer 6, and form an outer weather-resistant sheath layer 10 outside the inner sheath layer 9. S8, the common detection conductor 81 and the segmented detection conductor 82 are led out and encapsulated at the cable end to form the detection end 11.

[0044] The following examples, using a specific monitoring cable as an example, further illustrate the above preparation method in detail.

[0045] Example 1

[0046] The preparation method includes the following steps: S1, with a nominal cross-sectional area of ​​0.75mm². 2Conductor 1 is formed by stranding tin-plated soft round copper wires, with a stranding structure of 24 / 0.20mm. The DC resistance of the conductor at 20℃ is 25.8Ω / km. Insulation layer 2 is formed by extruding polyethylene-based insulation material around conductor 1, with a nominal thickness of 0.5mm. The insulation material, by weight, consists of: 70 parts linear low-density polyethylene, 30 parts high-density polyethylene, 8 parts silane-grafted polyethylene, 4 parts nano-silica aerogel masterbatch, 0.3 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 parts tris(2,4-di-tert-butylphenyl) phosphite, and 0.5 parts zinc stearate. The extrusion temperature is 160℃ to 185℃.

[0047] S2, four insulated wire cores are twisted together to form a cable core, the outermost layer has a pitch ratio of 10, the gaps between the wire cores are filled with polypropylene foam filling rope, and the cable core is wrapped with polyester tape to form an inner water-blocking wrapping layer 4, with a wrapping overlap rate of 18%.

[0048] S3, inner water-resistant wrapping layer 4, outer wrapping aluminum-plastic composite strip, aluminum foil side facing out, wrapping overlap rate 22%; metal braided layer 6 is formed by tin-plated copper wire with a diameter of 0.15mm, braiding density 86%.

[0049] S4, circumferential partition ribs 71 are formed on the outside of the metal braided layer 6 by intermittent molding. The partition rib material is a thermoplastic polyurethane elastomer and polyvinyl chloride elastic composite material (mass ratio 7:3). The axial distance between adjacent partition ribs is 200mm, the height is 0.45mm, the width is 4mm, and the measured peel strength between the partition ribs and the metal braided layer 6 is 1.35N / mm.

[0050] S5, each confined sealing chamber 72 is equipped with two water pressure driven flange check plates 73, which are inclined toward the two ends of the cable respectively; the fixed root 731 and the circumferential partition rib 71 are integrally formed, and the free flange 732 has an initial angle of 35° with the outer surface of the metal braid layer 6.

[0051] S6, each confined sealing chamber 72 is equipped with three types of trigger release chambers 74: a fracturing thin-walled chamber is set at the fixed root 731 near the water pressure driven flap check plate 73, which encapsulates silane-terminated polyether prepolymer and dibutyltin dilaurate catalyst, with a measured fracturing water pressure of 0.35 MPa; a swelling thin-walled chamber is set in the middle of the chamber, which encapsulates cross-linked sodium polyacrylate water-absorbing and swelling particles (D50 of 80 μm) and flake mica powder, with a measured opening time of 8 minutes after water ingress; a hydrolytic thin-walled chamber is set on the inner wall of the chamber, which encapsulates aramid short fibers and alkaline water stabilizer, with a measured opening time of 45 minutes after water ingress. The components, by mass parts, are: 100 parts silane-terminated polyether prepolymer, 18 parts cross-linked sodium polyacrylate water-absorbing and swelling particles, 0.8 parts dibutyltin dilaurate catalyst, 12 parts flake mica powder, and 3 parts aramid short fibers.

[0052] In S7, within the compartment coding diagnostic layer 8, both the common detection conductor 81 and the segment detection conductor 82 use a cross-sectional area of ​​0.08 mm². 2 The tin-plated copper wire; each confined sealing chamber 72 corresponds to an coded impedance unit 83, coded according to resistance value, arranged in a cycle of 10kΩ, 15kΩ, 22kΩ, 33kΩ, and 47kΩ; the coded impedance unit 83 is covered with a water-conducting layer 84, the formula of which, by weight, is: 100 parts polyvinyl butyral, 8 parts lithium chloride, 3 parts carbon black, 6 parts fumed silica, and 15 parts ethylene-vinyl acetate copolymer, with a measured water ingress response time of 2.5 min; an insulating isolation section 85 is provided between adjacent coded impedance units 83, corresponding to the position of the circumferential isolation rib 71.

[0053] S8 employs a double-layer co-extrusion process to form a gradient sheath layer. The inner embedded sheath layer 9 is extruded at a temperature of 158℃ and a die head pressure of 14MPa. The measured depth of the micro-gap embedded on the outer side of the circumferential partition rib 71 is 0.12mm to 0.18mm, the thickness is 0.45mm, and the Shore A hardness is 72. The outer weather-resistant sheath layer 10 is extruded at a temperature of 172℃, the thickness is 1.15mm, the Shore A hardness is 82, and the total thickness of the gradient sheath layer is 1.60mm.

[0054] The formula for the inner sheath layer 9, by weight, is as follows: 100 parts polyvinyl chloride resin, 22 parts trioctyl trimellitate, 15 parts polybutylene adipate, 10 parts ethylene-vinyl acetate copolymer, 10 parts thermoplastic polyurethane, 8 parts chlorinated polyethylene, 6 parts calcium-zinc composite heat stabilizer, 10 parts surface-treated nano calcium carbonate, 1 part hydrophobic silica, 0.3 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 parts tris(2,4-di-tert-butylphenyl) phosphite, and 0.5 parts stearic acid.

[0055] The outer weather-resistant sheath layer 10 formulation, by weight, consists of: 100 parts polyvinyl chloride resin, 18 parts trioctyl trimellitate, 12 parts polybutylene adipate, 8 parts dioctyl adipate, 10 parts chlorinated polyethylene, 6 parts thermoplastic polyurethane, 14 parts surface-treated nano-calcium carbonate, 1.5 parts hydrophobic silica, 5 parts flake mica powder, 6 parts calcium-zinc composite heat stabilizer, 0.6 parts bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 0.5 parts 2-(2-hydroxy-5-methylphenyl)benzotriazole, 0.3 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3 parts tris(2,4-di-tert-butylphenyl) phosphite, and 0.5 parts stearic acid.

[0056] S9, the ends of the common detection conductor 81 and the segmented detection conductor 82 are led out and packaged as detection terminals 11.

[0057] Example 2

[0058] This embodiment is basically the same as Embodiment 1, except that: this embodiment uses a seven-core cable, with conductor 1 having a nominal cross-sectional area of ​​0.35 mm². 2 The insulation layer 2 has a thickness of 0.4 mm; the axial distance between adjacent circumferential partition ribs 71 is 150 mm, the height is 0.35 mm, and the material is thermoplastic polyester elastomer with a measured peel strength of 1.18 N / mm; each compartment is equipped with one outward-facing and one inward-facing water-pressure driven flange check plate 73; the coded impedance units 83 are arranged in a cycle of 12 kΩ, 18 kΩ, 27 kΩ, 39 kΩ, and 56 kΩ; the water-conducting layer 84 has a water-conducting response time of 4.0 min; the total thickness of the gradient sheath layer is 1.45 mm, the head pressure of the inner embedded sheath layer 9 is 12 MPa, and the measured embedding depth is 0.09 mm to 0.14 mm.

[0059] Example 3

[0060] This embodiment is basically the same as Embodiment 1, except that: each confined sealing chamber 72 is provided with a first trigger release chamber (a thin-walled structure capable of fracturing, encapsulated with water-absorbing and expanding particles and sheet-like barrier filler, which is triggered synchronously with the water pressure-driven flange check sheet 73) and a second trigger release chamber (a thin-walled structure capable of hydrolysis, encapsulated with silane-terminated polyurethane prepolymer and catalyst, which is chemically cured after the check interface stabilizes), forming a two-stage sealing structure; the water-conducting layer 84 has a water-conducting response time of 2.0 min.

[0061] Example 4

[0062] This embodiment is basically the same as Embodiment 1, except that: the circumferential partition rib 71 is formed by laser-assisted hot melting, and the material is hydrogenated styrene-based elastomer with a measured peel strength of 1.22 N / mm; the water pressure driven flange check sheet 73 is made of silicone rubber, and the fixed root 731 is hot-pressed to the side wall of the partition rib; the coded impedance unit 83 is encoded with different RC time constants; the water-conducting layer 84 has a water-conducting response time of 3.0 min; the head pressure of the inner sheath layer 9 is 16 MPa, and the measured embedding depth is 0.15 mm to 0.22 mm.

[0063] The following section sets up six comparative examples, namely Comparative Examples 1-6.

[0064] Comparative Example 1: No compartmentalized self-sealing layer is set, only ordinary water-absorbing and expanding water-blocking strip is wrapped around it.

[0065] Comparative Example 2: Water-absorbing and expanding material and reactive sealing material are provided, but no circumferential partition ribs 71 are provided, and no confined sealing chamber 72 is formed.

[0066] Comparative Example 3: It is equipped with a circumferential partition rib 71 and a confined sealing chamber 72, but without a water pressure driven flap check plate 73.

[0067] Comparative Example 4: A self-sealing layer 7 is set for compartmentalized confinement, but no compartment coding diagnostic layer 8 is set.

[0068] Comparative Example 5: Set up a normal two-conductor leakage detection structure, without setting up a coding impedance unit 83 corresponding to each confined sealing chamber 72.

[0069] Comparative Example 6: The sheath layer is a single layer of ordinary soft polyvinyl chloride sheath, without a gradient sheath layer, and the extrusion process does not include a high-pressure interlocking step.

[0070] Performance testing The performance of the monitoring cables in the above embodiments and comparative examples was tested using test methods in accordance with GB / T2951, GB / T 3048, GB / T 1408.1, GB / T 16422.2, DL / T 1735-2017 and the technical requirements for monitoring cables in water conservancy and hydropower projects.

[0071] The test items include: (1) electrical performance, low temperature performance and water pressure resistance test; (2) long-term environmental tolerance test of the sheath; (3) compartment confinement sealing and compartment coding diagnosis performance test (3MPa water pressure test after micropore water ingress). The test results are shown in Tables 1-3.

[0072]

[0073]

[0074]

[0075] Tables 1 to 3 show that the ordinary water-absorbing and expanding water-blocking tape in Comparative Example 1 leaked after 120 hours, indicating that continuous water-blocking materials cannot reliably limit longitudinal water seepage diffusion under high water pressure. Comparative Example 2 did not have circumferential partition ribs, so the reactive sealing material could not be confined, and the longitudinal seepage length and sealing time both increased significantly, indicating that the confined sealing chamber is a necessary prerequisite for in-situ confined sealing. Comparative Example 3 did not have a flanged check valve, and the sealing response was significantly delayed, indicating that the mechanical check valve action plays an irreplaceable role in cutting off the water path and shortening the response time. Comparative Example 4 could not achieve compartment-level positioning, and the positioning error of Comparative Example 5 reached 1.6m, indicating that the structural design of one-to-one correspondence between the coded impedance unit and the confined sealing chamber, and the corresponding positions of the insulating isolation section and the partition rib, plays a key role in accurate positioning (error 0.20m to 0.35m). Comparative Example 6 had insufficient low-temperature performance and interface leakage occurred earlier, indicating that the bonding process of the gradient sheath layer makes a substantial contribution to the sealing of the compartment boundary.

[0076] In summary, this invention achieves compartmentalization, mechanical backflow prevention, in-situ sealing, and compartment positioning under high water pressure immersion conditions through the synergistic effect of circumferential partition ribs, confined sealing chambers, water pressure driven flap check valves, a three-stage ordered triggering sealing system, a compartment coding diagnostic layer, and a gradient interlocking sheath layer. This meets the usage requirements of long-term monitoring cables for water conservancy and hydropower projects.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific implementation of the present invention with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the pending claims.

Claims

1. A self-sealing and compartment-coded diagnostic monitoring cable with compartment-limited areas, characterized in that: It includes a cable core formed by twisting together multiple insulated wire cores and a protective layer disposed outside the cable core; The protective layer, from the inside out, includes an inner water-blocking wrapping layer (4), a composite shielding layer, a compartment-limited self-sealing layer (7), a compartment coding diagnostic layer (8), and a gradient sheath layer. The compartmentalized self-sealing layer (7) includes a plurality of circumferential isolation ribs (71) spaced apart along the length of the cable, a confinement sealing chamber (72) located between adjacent circumferential isolation ribs (71), and a water pressure driven flange check plate (73), a trigger release chamber (74), and a reactive sealing material (75) disposed in the confinement sealing chamber (72); the circumferential isolation ribs (71) extend along the circumference of the cable and form a press-fit or fusion seal with the outer surface of the composite shielding layer and the inner surface of the gradient sheath layer; The section coding diagnostic layer (8) includes a common detection conductor (81) extending along the cable length direction, segment detection conductors (82), and multiple coding impedance units (83); each of the confined sealing chambers (72) is provided with at least one of the coding impedance units (83), which is connected between the common detection conductor (81) and the segment detection conductors (82); the impedance characteristics of the coding impedance units (83) corresponding to different confined sealing chambers (72) are different from each other; the coding impedance unit (83) is covered with a water-conducting layer (84) or a water-dielectric-changing layer; The gradient sheath layer includes an inner embedded sheath layer (9) covering the compartment coding diagnostic layer (8) and an outer weather-resistant sheath layer (10) covering the inner embedded sheath layer (9); the inner embedded sheath layer (9) is simultaneously embedded in the micro gaps of the outer side of the circumferential partition rib (71), the outer surface of the compartment coding diagnostic layer (8) and the composite shielding layer under extrusion pressure, forming a mechanical interlocking structure with the circumferential partition rib (71).

2. The self-sealing and compartment coding diagnostic monitoring cable according to claim 1, characterized in that: The composite shielding layer includes a metal composite strip (5) wrapped around the inner water-blocking wrapping layer (4) and a metal braided layer (6) disposed outside the metal composite strip (5). The metal surface of the metal composite strip (5) faces outward and is in direct contact with the metal braided layer (6).

3. The self-sealing and compartment coding diagnostic monitoring cable according to claim 1, characterized in that: The circumferential partition rib (71) is made of one or more of thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, hydrogenated styrene elastomer, silicone rubber or polyvinyl chloride elastic composite material. The peel strength between the circumferential partition rib (71) and the outer surface of the composite shielding layer is not less than 1.0 N / mm. The axial distance between adjacent circumferential partition ribs (71) is 80 mm to 800 mm. The height of the circumferential partition rib (71) is 0.15 mm to 0.80 mm and the width is 1 mm to 8 mm.

4. The self-sealing and compartment coding diagnostic monitoring cable according to claim 1, characterized in that: The water pressure driven flange check plate (73) includes a fixed root (731) and a free flange (732); the fixed root (731) is fixed to the circumferential partition rib (71) or the outer surface of the composite shielding layer, and the free flange (732) is inclined towards the seepage direction, forming an initial angle of 15° to 75° with the outer surface of the composite shielding layer; when water enters the confined sealing chamber (72) under water pressure, the water pressure pushes the free flange (732) to fit against the adjacent interface to form a check seal interface.

5. The self-sealing and compartment coding diagnostic monitoring cable according to claim 1, characterized in that: The trigger release chamber (74) is formed by one or more of the following: a fracturing thin wall, a swelling thin wall, or a hydrolyzable thin wall; the reactive plugging material (75) includes a first plugging component and a second plugging component, which are stored separately in the trigger release chamber (74) or respectively set in different trigger release chambers (74) within the same confined plugging chamber (72); The first sealing component is one or more of silane-terminated polyether, silane-terminated polyurethane, isocyanate-terminated polyurethane prepolymer, or epoxy-modified silane prepolymer; the second sealing component is one or more of water-absorbing and swelling particles, moisture-curing catalyst, alkaline water stabilizer, sheet-like barrier filler, or fiber-reinforced filler.

6. The self-sealing and compartment coding diagnostic monitoring cable according to claim 1, characterized in that: The resistance value, RC time constant or LC resonant frequency of the coded impedance unit (83) are arranged in binary, arithmetic or geometric sequence; the water ingress response time of the water-conducting layer (84) or the water-dielectric change layer is no more than 5 min; an insulating isolation section (85) is provided between adjacent coded impedance units (83), and the insulating isolation section (85) corresponds to the axial position of the circumferential partition rib (71).

7. The self-sealing and compartment coding diagnostic monitoring cable according to claim 2, characterized in that: The inner water-resistant wrapping layer (4), the metal composite strip (5), the compartment-limited self-sealing layer (7), and the compartment coding diagnostic layer (8) all have overlapping seams, and the circumferential misalignment angle of the overlapping seams of adjacent layers is 30° to 150°; the circumferential partition rib (71) is set on both sides of the axial direction of the non-overlapping area of ​​the overlapping seam or the staggered area of ​​the overlapping seam.

8. The self-sealing and compartment coding diagnostic monitoring cable according to claim 1, characterized in that: The Shore A hardness of the inner sheath layer (9) is 5 to 25 lower than that of the outer weather-resistant sheath layer (10), and the thickness of the inner sheath layer (9) accounts for 20% to 55% of the total thickness of the gradient sheath layer; the total thickness of the gradient sheath layer is not less than 1.2 mm.

9. A compartmentalized, self-sealing layer, characterized in that, For use in hydraulic and hydropower engineering toughness monitoring cables, the compartmentalized self-sealing layer includes multiple circumferential partition ribs (71) spaced apart along the cable length, confinement sealing chambers (72) located between adjacent circumferential partition ribs (71), a water pressure driven flange check plate (73) disposed in the confinement sealing chamber (72), a trigger release chamber (74), and reactive sealing material (75); the circumferential partition ribs (71) are made of thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, hydrogenated styrene elastomer, silicone rubber, or polyvinyl chloride elastomer. Made of one or more of the composite materials, the peel strength between the composite material and the adjacent structural layer is not less than 1.0 N / mm; the water pressure driven flange check plate (73) includes a fixed root (731) and a free flange (732). When water enters the confined sealing chamber (72), the water pressure pushes the free flange (732) to fit against the adjacent interface to form a check seal interface, triggering the release chamber (74) to release the reactive sealing material (75). The reactive sealing material (75) forms a confined elastic sealing body (76) in the confined sealing chamber (72).

10. A method for preparing a compartment-confined self-sealing and compartment-coded diagnostic monitoring cable as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1, a conductor (1) is formed by stranding tin-plated soft round copper wire, and an insulating layer (2) is formed by extruding insulating material on the conductor (1) to obtain an insulated wire core; S2, multiple insulated wire cores are twisted together to form a cable core, non-hygroscopic elastic filler rope is filled between the insulated wire cores (3), and an inner water-blocking wrapping layer is formed by wrapping around the cable core (4). S3, wrap a metal composite strip (5) around the inner water-blocking wrapping layer (4) with the metal side facing outward, and then braid tin-plated copper wire to form a metal braided layer (6) to obtain a composite shielding layer; S4, using intermittent molding, intermittent extrusion, hot pressing or laser welding, multiple circumferential partition ribs (71) are formed at intervals along the cable length direction outside the composite shielding layer. These ribs are made of one or more of thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, hydrogenated styrene elastomers, silicone rubber or polyvinyl chloride elastic composite materials, so that the peel strength between the ribs and the composite shielding layer is not less than 1.0 N / mm. S5, a water pressure driven flange check plate (73), a trigger release chamber (74) and a reactive sealing material (75) are arranged between adjacent circumferential partition ribs (71) to form a confined sealing chamber (72) and thus obtain a compartmentalized confined self-sealing layer (7). S6, a common detection conductor (81), a segment detection conductor (82) and multiple coding impedance units (83) are set outside the compartment-limited self-sealing layer (7), so that each compartment-limited self-sealing compartment (72) corresponds to at least one coding impedance unit (83), forming a compartment coding diagnostic layer (8). S7, a gradient sheath layer is formed by co-extrusion or step extrusion. The inner sheath layer (9) is extruded by extrusion die. During extrusion, the melt pressure causes the material of the inner sheath layer (9) to simultaneously enter the micro gap outside the circumferential partition rib (71), the micro gap on the outer surface of the compartment coding diagnostic layer (8), and the micro gap of the metal braid layer (6), and form an outer weather-resistant sheath layer (10) outside the inner sheath layer (9). S8, the common detection conductor (81) and the segmented detection conductor (82) are led out at the cable end and encapsulated to form a detection end (11).

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