Heavy duty copper core sheathed mineral insulated cable

Abstract

This invention provides a heavy-duty copper-core sheathed mineral-insulated cable, comprising: conductors having multiple conductors; a mineral insulation layer covering the periphery of each conductor; an inner sheath layer including an inner sheath tape spirally wound around the outer periphery of the mineral insulation layer; and multiple inner protective strips densely distributed around the inner sheath tape, each inner protective strip being arranged along the length of the cable. Both the sheath tape and the inner protective strips are made of non-copper materials. The cable also includes an outer sheath layer made of copper, disposed outside the inner sheath layer; and a surface sheath layer disposed outside the outer sheath layer. This technical solution significantly reduces the overall copper consumption of the cable by using non-copper materials. Combined with the structural design of the inner layer retaining only the core protective function, it effectively reduces manufacturing costs while ensuring protective requirements, overcoming the cost limitations of traditional cables caused by the large amount of copper used.

Description

Technical Field

[0001] This invention generally relates to the field of cables, and specifically to a heavy-duty copper-core sheathed mineral-insulated cable. Background Technology

[0002] Heavy-duty copper-core sheathed mineral-insulated cables are a type of special cable with excellent fire resistance, high-temperature resistance, corrosion resistance, and explosion-proof properties. They are widely used in critical scenarios with extremely high requirements for power supply reliability and safety, such as fire emergency circuits in high-rise buildings, nuclear power plants, metallurgical and chemical industrial parks, and underground rail transit. Their core structure typically includes a copper core conductor, a mineral insulation layer (such as magnesium oxide powder) filling the outside of the conductor, and a copper sheath covering the insulation layer. Thanks to the excellent sealing, mechanical strength, and thermal and electrical conductivity of the copper sheath, combined with the non-combustible properties of the mineral insulation layer, these cables can maintain circuit integrity for extended periods in extreme fire environments, ensuring power supply to critical equipment and facilitating personnel evacuation.

[0003] However, existing heavy-duty copper-core sheathed mineral-insulated cables still have significant technical defects in actual production and application, specifically as follows: First, the cable's bending performance is poor, limiting its adaptability. In existing technologies, the sheath of heavy-duty copper-core sheathed mineral-insulated cables generally adopts a continuous seamless copper tube sheath. To meet the mechanical protection and fire resistance requirements of heavy-duty cables, the copper sheath needs to have a large thickness and high structural integrity, resulting in extremely high overall rigidity. Since the copper sheath is a one-piece continuous structure without any bendable or buffering design, during cable laying, especially in narrow spaces, irregular corners, or laying scenarios requiring frequent turns, bending is extremely difficult, requiring the assistance of specialized large equipment, significantly increasing construction costs and time. Furthermore, stress concentration during bending can easily lead to micro-cracks or even ruptures in the copper sheath, causing leakage and moisture absorption of the internal mineral insulation layer, seriously affecting the cable's insulation performance and fire resistance reliability, and greatly limiting its application in complex laying environments.

[0004] Secondly, the high manufacturing cost hinders large-scale promotion. As a high-value metal, copper's price fluctuations directly impact cable production costs. Existing heavy-duty copper-core sheathed mineral-insulated cables use an integrated continuous copper sheath, and the large cross-sectional dimensions of heavy-duty cables require a large amount of copper to ensure the sheath's mechanical strength and protective performance, resulting in high material costs. Furthermore, the production of continuous copper sheaths involves complex processes such as seamless copper tube drawing, composite compaction with the insulation layer and conductor, and continuous stretching, demanding extremely high precision in production equipment and process control, further increasing manufacturing costs. This high cost makes it difficult for this type of cable to be widely adopted in cost-sensitive applications, limiting its market reach and application expansion.

[0005] In summary, existing heavy-duty copper-core sheathed mineral-insulated cables, due to their continuous integrated copper sheath structure, suffer from prominent problems such as poor bending performance, insufficient adaptability, and high manufacturing costs, making it difficult to fully meet the construction needs and cost requirements of large-scale applications in today's complex laying environments. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a heavy-duty copper core sheathed mineral insulated cable, comprising: conductors having multiple layers; a mineral insulation layer covering the periphery of each conductor; an inner sheath layer including an inner sheath tape spirally wound around the outer periphery of the mineral insulation layer, and a plurality of inner protective strips densely distributed around the inner sheath tape, each inner protective strip being arranged along the length of the cable; the sheath tape and the inner protective strips being made of non-copper materials; and an outer sheath layer made of copper material disposed outside the inner sheath layer; and a sheath surface layer disposed outside the outer sheath layer.

[0007] With the aforementioned technical features, on the one hand, the inner layer of the sheath adopts a combination design of a non-copper spiral inner wrapping tape and dense inner protective strips arranged along the length direction. The spirally wound inner wrapping tape provides a good flexible foundation for the cable, allowing the cable to buffer bending stress through the deformation of the spiral structure during laying, greatly improving the overall bending performance. It is suitable for complex laying scenarios such as narrow spaces and irregular corners, avoiding the problem of cracks easily generated during bending due to the excessive rigidity of traditional integrated copper sheaths. It also plays a role in limiting and covering the inner mineral insulation layer. At the same time, the selection of non-copper materials can significantly reduce the overall copper consumption of the cable. Combined with the structural design of the inner layer retaining only the core protection function, it effectively reduces manufacturing costs while ensuring protection requirements, breaking through the cost limitations caused by the large amount of copper used in traditional cables. On the other hand, the densely distributed inner protective strips in the inner layer of the sheath are arranged along the length of the cable, which can form a uniform longitudinal protective skeleton, make up for the lack of mechanical strength of non-copper materials, and effectively resist physical damage such as external compression and wear. Together with the outer copper sheath, it forms a dual mechanical protection structure of flexible buffer and rigid protection.

[0008] In some embodiments, the outer sheath includes an outer sheathing tape made of copper, spirally wound around the outer periphery of the protective strip; and an outer protective strip, also made of copper, spirally wound around the outer periphery of the outer sheathing tape to press against the connection area between the outer sheathing tapes. This double-layer spiral winding structure gives the outer sheath excellent flexibility and deformation capability, allowing it to adapt to cable bending, buffering stress concentration during bending, preventing cracks or damage to the sheath, and significantly improving the cable's bending adaptability in complex laying scenarios. The spiral winding design of the copper outer sheathing tape effectively binds and secures the multiple inner protective strips, ensuring that adjacent inner protective strips are closely interdependent, further strengthening the structural stability of the longitudinal protective skeleton of the inner sheath, and guaranteeing the uniformity and reliability of the inner layer's protective performance. The copper outer protective strip is precisely pressed into the connection area of ​​the outer sheathing tape, which can fully fill the gaps formed by the spiral winding of the outer sheathing tape, effectively prevent the formation of connection gaps, build a tight sealed waterproof barrier, prevent external moisture and humidity from penetrating into the cable, avoid the mineral insulation layer from absorbing moisture and causing the insulation performance to decline, and significantly improve the cable's moisture and water resistance.

[0009] In some embodiments, the outer covering strip includes a raised area located in the middle region of the outer covering strip; and an extension area disposed on both sides of the raised area and integrally formed with the raised area; when the outer covering strip is spirally wrapped around the outside of the inner protective strip, the extension areas are superimposed on each other. Therefore, this structural design firstly, through the construction of the central raised area, allows the outer sheathing tape to better adapt to the outline of the inner protective strip during spiral winding, forming a tight fit with the surface of the inner protective strip and avoiding uneven stress on the inner protective strip due to gaps in the sheathing. At the same time, the extension areas on both sides overlap during the winding process, greatly enhancing the binding and securing effect of the outer sheathing tape on multiple inner protective strips, ensuring that adjacent inner protective strips always remain in close contact. Secondly, the overlapping setting of the extension areas can significantly reduce the gaps in the connection area after the outer sheathing tape is spirally wound, forming a preliminary sealing barrier. Combined with the subsequent pressing effect of the outer protective strip on the connection area, a dual waterproof protection system of overlapping sealing and pressing sealing is constructed, further improving the moisture-proof and waterproof capabilities of the outer sheath layer and preventing external moisture from penetrating into the cable interior and causing a decrease in the insulation performance of the mineral insulation layer.

[0010] In some embodiments, the outer protective strip has an inverted trapezoidal cross-section. When the outer protective strip is spirally wound around the outer covering tape, it is pressed against the outside of the extension area, and the raised area is located in the gap between adjacent outer protective strips. This inverted trapezoidal cross-section design allows the outer protective strip to utilize its trapezoidal structure to generate a uniform and downward compressive force when pressing against the overlapping area of ​​the outer covering tape's extension area. This further compacts the overlapping portion of the extension area, strengthening the binding and securing effect of the outer covering tape on the inner protective strip. Simultaneously, the raised area of ​​the outer covering tape is embedded in the gap between adjacent outer protective strips, allowing for precise filling of the gap using the structure of the raised area. This prevents the formation of a through gap after the outer protective strip is spirally wound, creating a double sealing barrier of outer protective strip pressing and raised area filling. This significantly enhances the waterproof and moisture-proof capabilities of the outer sheath, ensuring that the internal mineral insulation layer does not lose insulation performance due to moisture absorption. In addition, the adaptability design of the raised area and the gap of the outer protective strip can keep the outer surface of the sheath flat, avoid stress concentration caused by local protrusions, retain the flexibility advantage of the spiral structure, and ensure that the outer layer of the sheath is not prone to cracks or damage when the cable is bent in complex scenarios.

[0011] In some embodiments, each inner protective strip has a groove along its length on its outer side, and a copper limiting strip is disposed in the groove to leave a gap between the inner protective strip and the outer sheath after the outer sheath is wrapped. Thus, this design, after the outer sheath is wrapped, can form a stable gap between the inner protective strip and the outer sheath with the support of the limiting strip. This gap can serve as a deformation buffer space when the cable is bent, effectively reducing the frictional resistance between the outer sheath and the inner protective strip, avoiding stress concentration due to tight contact, and further improving the overall flexible bending performance of the cable, making it more suitable for laying in narrow corners and complex paths. Furthermore, the copper limiting strip and the copper outer sheath form a stable and reliable metal contact area, eliminating the potential for poor conductivity caused by contact gaps, strengthening the overall conductivity of the outer sheath layer, and ensuring the continuity and reliability of the grounding circuit.

[0012] In some embodiments, a sealing layer composed of mineral insulating material is provided within the gap. Thus, the sealing layer, made of mineral insulating material identical to the core insulation structure of the cable, forms a dense protective barrier after filling the gap. On one hand, it completely blocks the path of moisture and humidity into the cable through the gap, preventing the internal mineral insulation layer from absorbing moisture and causing a decline in insulation performance. Simultaneously, it isolates the cable from external corrosive gases, further enhancing its moisture and corrosion resistance, making it suitable for harsh application environments such as humid, coastal, and chemical environments. On the other hand, the mineral insulating material itself possesses excellent high-temperature resistance and non-flammability, forming a dual fireproof insulation system with the cable's mineral insulation layer. This maintains structural stability under high-temperature fire conditions, preventing the gap from becoming a channel for flame spread, ensuring the integrity of the cable circuit, and strengthening the fire safety performance of heavy-duty cables.

[0013] In some embodiments, multiple limiting protrusions are formed on the bottom surface of the extension area on one side of the outer covering tape along its length direction. This allows the protruding area on the side without limiting protrusions to adhere to the back side of the extension area on the side with limiting protrusions when the outer covering tape is spirally wound. Thus, the limiting protrusions and limiting strips form a precise limiting fit, further strengthening the binding and restraining effect of the outer covering tape on the inner protective strips, causing the multiple inner protective strips to hug each other more tightly. Secondly, the limiting protrusions can directly contact the mineral insulating material within the gaps. With the support and compression effect of the limiting protrusions, the mineral insulating material is pushed to fully fill the gaps between adjacent inner protective strips, eliminating the potential space hazards left in the gaps and ensuring that the mineral insulating material is evenly and densely distributed within the gaps.

[0014] In some embodiments, a gap-filling layer is provided within the gap formed by the top of the protrusion and the outer protective strips on both sides. The gap-filling layer comprises mineral insulating powder. Thus, the gap-filling layer, using mineral insulating powder of the same composition as the core insulation structure of the cable, can fully fill the gap between the protrusion and the outer protective strip, completely blocking the path of external media such as moisture and humidity into the cable along the gap. This prevents the internal mineral insulation layer from absorbing moisture and causing a decrease in insulation performance, significantly improving the cable's moisture-proof sealing capability. Simultaneously, the mineral insulating powder itself possesses excellent high-temperature resistance and non-flammability, forming a synergistic protection with the overall fireproof structure of the cable, effectively preventing the gap from becoming a channel for flame spread, further strengthening the circuit integrity of the cable in extreme fire environments, and ensuring power supply reliability in critical scenarios. Furthermore, the powder filling layer allows for a tighter connection between the protrusion and the outer protective strip, enhancing the density and stability of the outer sheath structure, and preventing structural damage caused by stress concentration at the gap when the cable is bent.

[0015] In some embodiments, a fireproof bag is also included for filling the mineral insulating powder. Thus, the fireproof bag can serve as a dedicated container for the mineral insulating powder, enabling convenient and precise filling and positioning of the powder, preventing it from scattering or shifting during cable processing, transportation, or laying, and ensuring that the mineral insulating powder remains in the preset filling position.

[0016] In some embodiments, a supporting keel is provided in the middle of the plurality of conductors. The supporting keel has a receiving groove on one side facing each conductor, with a gap between the conductor and the receiving groove. The mineral insulation layer is located within the gap. Thus, the supporting keel, through the receiving groove, can precisely position and limit each conductor, preventing displacement and entanglement of multiple conductors during cable processing, transportation, or laying, ensuring the regularity and stability of the conductor arrangement. Simultaneously, the gap between the conductor and the receiving groove provides ample filling space for the mineral insulation layer, ensuring that the mineral insulation layer can uniformly and densely cover the conductor, fully exerting its insulation and fire-resistant functions, and preventing localized insulation weaknesses due to conductor adhesion. Furthermore, the supporting keel can serve as the internal support skeleton of the cable, significantly improving the overall structural strength and tensile and compressive resistance of heavy-duty cables, adapting to the usage requirements of heavy-duty scenarios, while ensuring that the mineral insulation layer is not easily damaged under external forces, further enhancing the reliability of cable operation.

[0017] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0018] Figure 1 A cross-sectional schematic diagram of a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention is shown;

[0019] Figure 2 This diagram illustrates the structure of the inner sheath layer in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention.

[0020] Figure 3 This diagram illustrates the structure of the outer sheath layer in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention.

[0021] Figure 4 A cross-sectional schematic diagram of a gap-filling layer in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention is shown.

[0022] Figure 5 A schematic diagram of the outer sheathing tape in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention is shown.

[0023] Symbol Explanation

[0024] 1. Conductor; 11. Supporting keel; 2. Mineral insulation layer; 3. Inner sheath layer; 31. Inner covering tape; 32. Inner protective strip; 4. Outer sheath layer; 41. Outer covering tape; 411. Raised area; 412. Extension area; 413. Limiting protrusion; 42. Outer protective strip; 5. Sheath surface layer; 6. Limiting strip; 7. Sealing layer; 8. Gap filling layer; 81. Fireproof bag. Detailed Implementation

[0025] The preferred embodiments (or implementation methods) of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] The following is for reference. Figures 1-5 This invention describes a heavy-duty copper-core sheathed mineral-insulated cable.

[0027] Figure 1 A cross-sectional schematic diagram of a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention is shown. Figure 2 A schematic diagram of the structure of the inner sheath layer 3 in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention is shown. (Reference) Figure 1 and Figure 2 As shown, a heavy-duty copper-core sheathed mineral-insulated cable includes: a conductor 1, a mineral insulation layer 2, an inner sheath layer 3, an outer sheath layer 4, and a sheath surface layer 5. Multiple conductors 1 are provided, and the mineral insulation layer 2 covers the periphery of each conductor 1. The inner sheath layer 3 includes an inner sheathing tape 31 spirally wound around the outer periphery of the mineral insulation layer 2, and multiple inner protective strips 32 densely distributed around the inner sheathing tape 31. Each inner protective strip 32 is arranged along the length of the cable. Both the inner sheathing tape 31 and the inner protective strips 32 are made of non-copper materials. The cable also includes an outer sheath layer 4, made of copper, located outside the inner sheath layer 3, and a sheath surface layer 5, located outside the outer sheath layer 4.

[0028] Conductor 1 refers to the core component of the cable used to transmit electrical energy, serving as the carrier of current flow. In this design, a copper core is used to ensure excellent conductivity. Mineral insulation layer 2 is an insulating medium with inorganic mineral materials (such as magnesium oxide) as its core. It possesses characteristics such as high temperature resistance, non-flammability, and stable insulation performance, making it a key structure for achieving the cable's fire-resistant insulation function. Inner sheath layer 3 is the inner protective structure of the cable, used to wrap the mineral insulation layer 2 and provide basic protection. Its inner covering tape 31 is a thin, wide strip structure spirally wound around the outside of the mineral insulation layer 2, primarily serving as initial coverage and flexible buffering. Inner protective strips 32 are strip-shaped structures densely distributed along the cable length on the outside of the inner covering tape 31, used to strengthen the inner protective layer. Outer sheath layer 4 is a protective structure located outside the inner sheath layer 3, made of copper, used to ensure the cable's core protective performance. Sheath surface layer 5 is the outermost protective structure of the cable, used to further improve the cable's environmental adaptability.

[0029] Specifically, in this solution, the inner covering strip 31 and the inner protective strip 32 can be made of stainless steel. Stainless steel is an alloy material that combines excellent corrosion resistance, mechanical strength and a certain degree of ductility, which can precisely match the functional requirements of the inner layer 3 of the sheath.

[0030] The design employs a multi-conductor configuration 1, coupled with an independently encased mineral insulation layer 2, ensuring reliable insulation between each conductor 1 and preventing leakage or interference issues. It also meets the multi-channel power supply requirements of heavy-duty cables. The inner sheath layer 3 utilizes a combination of a non-copper inner sheathing tape 31 and inner protective strips 32. The spirally wound inner sheathing tape 31 provides excellent flexibility, allowing the cable to adapt flexibly to complex paths and corners during installation, effectively solving the problem of excessive rigidity and difficulty in bending inherent in traditional integrated copper sheaths. The densely arranged inner protective strips 32 along the length form a robust longitudinal protective framework, compensating for the mechanical strength deficiencies of non-copper materials and effectively resisting external pressure, abrasion, and other physical damage, providing reliable protection for the internal structure. The outer sheath layer 4 is made of copper, fully retaining the excellent fire resistance, moisture-proof, corrosion-resistant, and conductive properties of copper sheaths. This ensures the cable maintains circuit integrity even in extreme fire environments and enables reliable grounding, guaranteeing power supply safety in critical scenarios and preventing a decline in core protective performance due to the use of non-copper materials in the inner layer. The outermost sheath layer 5 further enhances the cable's environmental adaptability, enabling it to resist corrosion from harsh external environments in different usage scenarios and extend the cable's service life.

[0031] In some embodiments, reference Figure 1 As shown, a supporting keel 11 is provided in the middle of multiple conductors 1. The supporting keel 11 has a receiving groove on one side facing each conductor 1. A gap is left between the conductor 1 and the receiving groove, and the mineral insulation layer 2 is located in the gap.

[0032] The support keel 11 is an internal support structure set in the middle of multiple conductors 1. It is mainly used to provide rigid support for the inside of the cable and to position each conductor 1. Its material is usually selected as metal or composite insulation material with high strength and stability. The receiving groove is a groove structure opened on one side of the support keel 11 facing each conductor 1. Its size is adapted to the conductor 1 and is used to accurately accommodate and limit the conductor 1.

[0033] The support keel 11 provides a stable internal support framework for the entire cable, effectively improving the overall structural strength and deformation resistance of the heavy-duty cable. It can withstand tensile and compressive forces generated during laying and use, preventing performance damage due to internal structural loosening or deformation. The receiving grooves on the support keel 11 can precisely position and limit each conductor 1, ensuring that multiple conductors 1 maintain a preset spacing. This effectively prevents displacement, entanglement, or mutual friction between conductors 1, guaranteeing the regularity of the conductor arrangement. This is crucial for meeting the multi-channel power supply requirements of heavy-duty cables and avoiding signal interference or short-circuit risks between conductors 1. The gap between the conductor 1 and the receiving groove provides ample space for the filling of the mineral insulation layer 2, ensuring that the mineral insulation layer 2 can uniformly and densely cover the periphery of the conductor 1. It prevents weak areas of insufficient insulation caused by tight contact between the conductor 1 and the receiving groove, thus fully utilizing the insulation, fire resistance, and high-temperature resistance properties of the mineral insulation layer 2, further enhancing the safety and reliability of the cable. Meanwhile, the mineral insulation layer 2 filling the gaps can also work together with the supporting keel 11 and the receiving groove to fix it, further restricting the movement space of the conductor 1, improving the stability of the conductor 1 inside the cable, ensuring that the internal structure of the heavy cable can remain stable during long-term operation under complex working conditions, and ensuring the continuity and safety of power supply.

[0034] In some embodiments, Figure 3 This diagram illustrates the structure of the outer sheath layer 4 in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention. (Refer to...) Figure 3 As shown, the outer sheath 4 includes an outer covering tape 41 and an outer protective strip 42. The outer covering tape 41 is made of copper and is spirally wound around the outer periphery of the protective strip. The outer protective strip 42 is made of copper and is spirally wound around the outer periphery of the outer covering tape 41 to press against the connection area between the outer covering tapes 41.

[0035] The outer covering tape 41 is an inner layer component of the outer sheath 4. It is a strip structure made of copper and is wrapped around the outer side of the inner protective strip in a spiral manner, serving as a preliminary covering, conducting current, and providing auxiliary protection. The outer protective strip 42 is an outer layer component of the outer sheath 4. It is also a strip structure made of copper and is spirally wrapped around the outer side of the outer covering tape 41. Its core function is to compact the connection area of ​​the outer covering tape 41 and enhance the overall protective performance.

[0036] The double-layer spiral winding structure completely breaks through the limitations of the traditional one-piece copper sheath's excessive rigidity, giving the outer layer 4 excellent flexibility and deformation capabilities. During cable laying, it can bend flexibly according to changes in the path, effectively buffering stress concentration during bending and preventing cracks or damage to the sheath. This significantly improves the cable's adaptability in complex scenarios such as narrow spaces and irregular corners. The outer sheath tape 41, made of copper and spirally wound, leverages copper's excellent conductivity to form a stable conductive circuit, ensuring reliable cable grounding. The outer protective strip 42 is specifically spirally pressed onto the connection area of ​​the outer sheath tape 41. On one hand, it completely blocks the intrusion path of moisture, humidity, and corrosive substances, strengthening the cable's sealing, moisture-proof, and corrosion-proof capabilities. On the other hand, leveraging copper's excellent high-temperature resistance and structural stability, it works in conjunction with the outer sheath tape 41 to form a dual fireproof and fire-resistant system, ensuring the cable maintains circuit integrity even in extreme fire environments, guaranteeing power supply safety in critical scenarios.

[0037] In some embodiments, the outer covering strip 41 includes a raised area 411 and an extended area 412. The raised area 411 is located in the middle region of the outer covering strip 41. The extended areas 412 are disposed on both sides of the raised area 411 and are integrally disposed with the raised area 411. When the outer covering strip 41 is spirally wrapped around the outside of the inner protective strip 32, the extended areas 412 are stacked on top of each other.

[0038] The raised area 411 is a raised structure integrally formed in the middle area of ​​the outer wrapping tape 41. Its shape is adapted to the outer contour of the inner protective strip 32 to improve the fit between the outer wrapping tape 41 and the inner protective strip 32. The extended area 412 is the extended part integrally formed on both sides of the outer wrapping tape 41 and the raised area 411. It has a certain degree of flexibility and extensibility. Its core function is to achieve tight wrapping and sealing by superposition during spiral winding.

[0039] The raised area 411 allows the outer covering tape 41 to precisely fit the outline of the inner protective strip 32 during winding, forming a tight fit with the surface of the inner protective strip 32. This prevents uneven stress on the inner protective strip 32 caused by gaps between the two, and also provides structural support for the outer covering tape 41, enhancing its resistance to deformation. The extension areas 412 on both sides overlap during spiral winding, significantly improving the binding and securing effect of the outer covering tape 41 on the multiple inner protective strips 32.

[0040] In some embodiments, the outer protective strip 42 has an inverted trapezoidal cross-section. When the outer protective strip 42 is spirally wound around the outer covering strip 41, the outer protective strip 42 is pressed onto the outside of the extension area 412, and the protruding area 411 is located in the gap between adjacent outer protective strips 42. The inverted trapezoidal cross-section refers to the fact that the cross-section of the outer protective strip 42 is in the shape of an inverted trapezoid, that is, the upper side is wider and the lower side is narrower. This shape can accurately adapt to the pressing requirements and has both good fit and stress stability.

[0041] The inverted trapezoidal cross-section allows the narrower lower portion of the outer protective strip 42 to precisely embed into the gap of the overlapping area of ​​the extension area 412 when it is pressed onto the outside of the outer covering strip 41. The wider upper portion provides a larger pressing contact area, forming a uniform and downward pressing force. This further compacts the overlapping part of the extension area 412, strengthening the binding and fastening effect of the outer covering strip 41 on the inner protective strip 32. The raised area 411 of the outer covering strip 41 is precisely embedded into the gap between adjacent outer protective strips 42. Combined with the shape of the outer protective strip 42 being wider at the top and narrower at the bottom, the outer protective strips 42 on both sides of the gap can form a symmetrical clamping and limiting effect on the raised area 411. This not only fully fills the gap formed after the outer protective strip 42 is spirally wound, avoiding through gaps, but also strengthens the structural integrity of the outer layer 4 of the sheath. It works synergistically with the pressing and sealing of the outer protective strip 42 to build a double sealing barrier, significantly improving the waterproof, moisture-proof and corrosion-proof capabilities of the outer layer 4 of the sheath.

[0042] In some embodiments, Figure 4 A cross-sectional schematic diagram of the gap-filling layer 8 in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention is shown. (Refer to...) Figure 4 As shown, a gap filling layer 8 is provided in the gap formed by the top of the protruding area 411 and the outer protective strips 42 on both sides. The gap filling layer 8 includes mineral insulating material powder and a fireproof bag 81 for filling the mineral insulating material powder.

[0043] The gap filling layer 8 is a protective structure that fills the gap formed by the top of the protrusion and the outer protective strips 42 on both sides. Its core component is mineral insulating powder, which is used to fill gaps and enhance sealing and fire resistance. The mineral insulating powder is a powdered insulating medium made from inorganic minerals such as magnesium oxide. It has the characteristics of high temperature resistance, non-flammability, stable insulation performance and good sealing. The fireproof bag 81 is a special carrier container for filling the mineral insulating powder. It has fireproof and flame-retardant properties, can fix the position of the powder and help improve the fireproof effect.

[0044] The fireproof bag 81, as a dedicated carrier structure for the powder, can precisely fix the mineral insulating powder in the target gap area, effectively preventing the powder from scattering or shifting during cable processing, transportation, laying, or bending. This ensures that the filling layer is always in the preset protective position, guaranteeing the stability of the protective effect. The mineral insulating powder filling the gaps can fully fill the gaps between the protrusions and the outer protective strip 42, completely blocking the path of moisture, humidity, and corrosive gases to penetrate into the cable along the gaps. This prevents the insulation performance of the internal mineral insulation layer 2 from deteriorating due to moisture absorption or corrosion, significantly improving the cable's sealing, moisture-proof, and corrosion-proof capabilities.

[0045] In some embodiments, each inner protective strip 32 has a groove along its length on its outer side, and a copper limiting strip 6 is provided in the groove to leave a gap between the inner protective strip 32 and the outer covering strip 41 after the outer covering strip 41 is wrapped around it. The limiting strip 6 is a copper strip-shaped component embedded in the groove, used to support the outer covering strip 41 and leave the gap, while also serving as a limiting and conductive function.

[0046] The limiting strip 6 is precisely embedded in the groove, providing stable constraint on the spirally wound outer sheath 41. This strengthens the binding effect of the outer sheath 41 on the inner protective strip 32, ensuring that the multiple inner protective strips 32 remain tightly bound together, thus stabilizing the protective structure of the inner layer 3 of the sheath. The copper limiting strip 6 not only possesses sufficient structural strength to support the outer sheath 41, but also, thanks to copper's excellent conductivity, forms reliable metal-to-metal contact with the copper outer sheath 41. This enhances the overall conductivity of the sheath structure, compensates for the conductivity limitations of the non-copper inner protective strip 32, and ensures the continuity and reliability of the cable grounding circuit.

[0047] In some embodiments, reference Figure 1 As shown, a sealing layer 7 composed of mineral insulating material is disposed within the gap. This gap refers to the space formed between the inner protective strip 32 and the outer covering strip 41, supported by a copper limiting strip 6, which was originally used to provide deformation buffer and heat dissipation channel for cable bending. The sealing layer 7 is a protective structure filling the gap, and its core component is mineral insulating material, possessing multiple functions such as sealing, insulation, and fire resistance.

[0048] The sealing layer 7 is made of mineral insulation material. After filling the gaps, it forms a dense protective barrier, completely blocking the path of moisture, humidity, and corrosive gases to penetrate into the cable through the gaps. This prevents the core mineral insulation layer 2 from losing its insulation performance due to moisture absorption or corrosion, significantly improving the cable's moisture and corrosion resistance, making it suitable for harsh environments such as humid, coastal, and chemical applications. Furthermore, the sealing layer 7 has a certain degree of flexibility and deformation capability. After filling, it does not destroy the original deformation buffering function of the gaps. When the cable is bent, the sealing layer 7 can adapt to the shape of the gaps, effectively reducing the frictional resistance between the outer sheath 41 and the inner protective strip 32, thus balancing the cable's structural stability and flexible laying adaptability.

[0049] In some embodiments, Figure 5 This diagram illustrates the structure of the outer sheathing tape 41 in a heavy-duty copper-core sheathed mineral-insulated cable according to an embodiment of the present invention. (Refer to...) Figure 5 As shown, multiple limiting protrusions 413 are formed along the length direction on the bottom surface of the extension area 412 on one side of the outer covering tape 41, so that when the outer covering tape 41 is spirally wound, the protrusion area 411 on the side without the limiting protrusions 413 attaches to the back side of the extension area 412 on the side with the limiting protrusions 413. The limiting protrusions 413 are protrusion structures formed along the length direction on the bottom surface of the extension area 412 on one side of the outer covering tape 41.

[0050] The limiting protrusion 413 and the limiting strip 6 form a precise and coordinated limiting relationship, which can provide a stable constraint on the spirally wound outer sheath 41, preventing circumferential slippage of the outer sheath 41 during cable processing, transportation, or laying. This strengthens the binding and securing effect of the outer sheath 41 on the inner protective strip 32, causing multiple inner protective strips 32 to hug each other more tightly, fundamentally preventing the inner protective strips 32 from shifting or loosening, and stabilizing the longitudinal protective skeleton structure of the inner sheath layer 3. At the same time, during the process of cooperating with the limiting strip 6, the limiting protrusion 413 will directly contact the mineral insulation material sealing layer 7 in the gap between the inner protective strip 32 and the outer sheath 41. With the squeezing action generated by the two, the mineral insulation material is pushed to fully fill the gap between adjacent inner protective strips 32, eliminating the potential for gaps, ensuring that the sealing layer 7 is evenly and densely distributed, further improving the cable's sealing, insulation, and fire resistance performance, and taking into account both structural stability and core protective functions.

[0051] In the description of this specification, the terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0052] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A heavy-duty copper-core sheathed mineral-insulated cable, characterized in that, include: Conductor (1), wherein multiple conductors (1) are provided. A mineral insulating layer (2) is provided, which covers the periphery of each conductor (1). The inner sheath layer (3) includes an inner sheath tape (31) spirally wound around the outer periphery of the mineral insulation layer (2), and a plurality of inner protective strips (32) densely distributed around the inner sheath tape (31) on the outer periphery of the inner sheath tape (31). Each inner protective strip (32) is arranged along the length of the cable. Both the inner sheath tape (31) and the inner protective strips (32) are made of non-copper material. The outer sheath layer (4), made of copper, is disposed outside the inner sheath layer (3). The outer sheath layer (4) includes... An outer covering tape (41) is made of copper and is spirally wound around the outer periphery of the protective strip. The outer covering tape (41) includes a raised area (411) located in the middle region of the outer covering tape (41); and an extension area (412) disposed on both sides of the raised area (411) and integrally formed with the raised area (411). When the outer covering tape (41) spirally wound around the outside of the inner protective strip (32), the extension areas (412) are stacked on top of each other. A gap filling layer (8) is provided in the gap formed between the top of the protruding area (411) and the outer protective strips (42) on both sides. The gap filling layer (8) includes mineral insulating material powder and also includes a fireproof bag (81) for filling the mineral insulating material powder. The outer protective strip (42) is made of copper and is spirally wound around the outer periphery of the outer covering strip (41) to press against the connection area between the outer covering strips (41). The cross-section of the outer protective strip (42) is an inverted trapezoid. When the outer protective strip (42) is spirally wound around the outer covering strip (41), the outer protective strip (42) is pressed against the outside of the extension area (412). The protrusion area (411) is located in the gap between adjacent outer protective strips (42). Each inner protective strip (32) has a groove along its length on its outer side. A copper limiting strip (6) is provided in the groove to leave a gap between the inner protective strip (32) and the outer covering strip (41) after the outer covering strip (41) is wound. A sealing layer (7) composed of mineral insulating material is provided in the gap. On the bottom surface of the extension area (412) on one side of the outer covering tape (41), a plurality of limiting protrusions (413) are provided along its length direction, so that when the outer covering tape (41) is spirally wound, the protrusion area (411) on the side without the limiting protrusion (413) is attached to the back side of the extension area (412) on the side of the limiting protrusion (413), and the limiting protrusion (413) is engaged with the limiting strip (6); Sheath surface layer (5), which is disposed outside the outer layer (4) of the sheath.

2. The heavy-duty copper-core sheathed mineral-insulated cable according to claim 1, characterized in that, A supporting keel (11) is provided in the middle of the plurality of conductors (1), and the supporting keel (11) has a receiving groove on one side facing each conductor (1), with a gap between the conductor (1) and the receiving groove, and the mineral insulating layer (2) is located in the gap.

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