Anti-freezing buried cable with phase change sheath
The anti-freeze buried cable with phase change sheath and airbag buffer structure solves the problem of frost heave of buried cables in cold regions, achieves flexible protection and high pressure resistance, simplifies the installation process and reduces costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RUIYANG GRP NORTHEAST CABLE CO LTD
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-22
Smart Images
Figure CN121812263B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cable technology, and in particular to a freeze-resistant underground cable with a phase change sheath. Background Technology
[0002] With the continuous development of infrastructure such as power and communication, cables, as an important medium for power transmission and information transmission, are increasingly diversified in their laying methods. Underground cables are widely used due to their advantages such as not occupying above-ground space, anti-theft, and corrosion resistance. However, in cold regions, underground cables face a severe problem of frost heave. When the moisture in the soil freezes, its volume expands, generating huge frost heave pressure, which causes compression, stretching, and even shearing effects on the underground cables, resulting in damage to the cable insulation layer and conductor breakage, seriously affecting the service life and operational safety of the cables.
[0003] Existing methods for protecting buried cables from freezing primarily rely on steel tape armor to increase the cable's mechanical strength. However, while steel tape armor provides high compressive strength, it increases the cable's rigidity and weight, leading to installation difficulties and potential failure under extreme frost heave pressure, while also increasing costs. Therefore, the effectiveness, economy, and ease of installation of existing buried cable antifreeze designs still need improvement. Summary of the Invention
[0004] The technical problem to be solved by this invention is the problem of frost heave faced by underground cables in cold regions. To address this, we propose an anti-freeze underground cable with a phase change sheath.
[0005] To achieve the above objectives, this application adopts the following technical solution: a freeze-resistant buried cable with a phase change sheath, comprising a freeze-resistant cable and a low-temperature phase change sheath coaxially wrapped around the outside of the freeze-resistant cable; the low-temperature phase change sheath is composed of six or more sets of arc-shaped splicing strips, and multiple sets of arc-shaped splicing strips are interlocked by end-fitting structures to form a complete annular sheath structure, which coaxially wraps the freeze-resistant cable inside; the inner wall of the arc-shaped splicing strip is provided with a phase change chamber, which is a narrow cavity extending along the length direction of the arc-shaped splicing strip, and the cavity is filled with It contains a phase change filling material with a phase change temperature higher than 25℃; the outer wall of the arc-shaped splicing strip is provided with an airbag buffer chamber, which is arranged in parallel with the phase change chamber along the radial direction of the arc-shaped splicing strip; both ends of the arc-shaped splicing strip are provided with positioning slots along their length, the groove shape of which is adapted to the cross-sectional shape of the heating belt, and the heating belt is fixed in the positioning slots; the outer side of the low-temperature phase change sheath is entirely covered with a layer of thermal insulation cotton, and the outer side of the thermal insulation cotton is evenly wrapped with fiberglass wrapping tape along its circumference to form a puncture-proof and corrosion-proof protective layer.
[0006] Preferably, the antifreeze cable includes a conductor core, a conductor insulation layer coaxially wrapped around the outside of the conductor core, an insulating sheath coaxially wrapped around the outside of the conductor insulation layer, and a filler layer filling the annular gap between the insulating sheath and the conductor insulation layer. The filler layer is used to fill the gap, fix the conductor insulation layer, and at the same time help improve the overall tensile and compressive strength of the antifreeze cable.
[0007] Preferably, in addition to the phase change filling material, the phase change chamber is also uniformly filled with chopped glass fibers as a reinforcing phase component. The chopped glass fibers and the phase change filling material are thoroughly mixed to form a uniform composite system, which is used to improve the structural strength and durability of the phase change filling material.
[0008] Preferably, the phase change filler material is a phase change composite system formed by compounding polyethylene glycol and paraffin wax, wherein the mass proportion of polyethylene glycol is 65% to 80%, the mass proportion of paraffin wax is 20% to 35%, and the sum of the mass proportions of polyethylene glycol and paraffin wax is 100%; the phase change temperature of the composite system is precisely controlled at 28℃ to 32℃ to adapt to the temperature change requirements of the buried environment and ensure the stable performance of the phase change function.
[0009] Preferably, the phase change filler material also contains an antioxidant at a mass ratio of 1% to 3%, specifically 2,6-di-tert-butyl-p-cresol; the antioxidant is uniformly dispersed in the phase change filler material to slow down the aging and deterioration rate of the phase change filler material under long-term hot and cold cycling conditions, extend its service life, and ensure the long-term stability of the phase change protection function.
[0010] Preferably, the chopped glass fibers have a length of 3mm to 8mm and a diameter of 10μm to 20μm, and their volume percentage in the phase change chamber is 5% to 10%. The chopped glass fibers are uniformly dispersed in the phase change filler material, which can effectively improve the compressive strength and structural stability of the phase change filler material after solidification, and avoid cracking and falling off of the phase change filler material after solidification.
[0011] Preferably, the airbag buffer chamber has a central partition wall integrally formed inside. The central partition wall extends radially along the arc-shaped splicing strip, which evenly divides the airbag buffer chamber into two independent buffer chambers. The central partition wall can enhance the structural rigidity of the airbag buffer chamber, while making the buffering force evenly distributed and improving the buffering effect against external frost heave pressure.
[0012] Preferably, a nickel-chromium alloy heating core is embedded inside the heating band, which is the core heating component of the heating band. The nickel-chromium alloy heating core is covered with a layer of Teflon high-temperature cloth, and glass fiber cloth is filled between the Teflon high-temperature cloth and the nickel-chromium alloy heating core as an insulating substrate. The insulating substrate is used to achieve insulation protection for the nickel-chromium alloy heating core, prevent leakage, and improve the high-temperature resistance of the heating band.
[0013] Preferably, the fiberglass wrapping tape is made of alkali-free fiberglass yarn, with a wrapping overlap rate of 30% to 50% and a wrapping thickness of 2mm to 5mm, ensuring that the wrapping layer is seamless and fully covered. The outer surface of the fiberglass wrapping tape is coated with a layer of polyvinyl chloride anti-corrosion coating, which can significantly enhance the puncture resistance and corrosion resistance of the fiberglass wrapping tape, while improving its resistance to soil erosion, making it suitable for complex underground soil environments and long-term buried working conditions.
[0014] Preferably, the heating strips are continuously laid along the length of the arc-shaped splicing strips, and the ends of the heating strips on two adjacent sets of arc-shaped splicing strips are detachably electrically connected through conductive terminals to ensure that multiple sets of heating strips form a complete heating circuit; the rated voltage of the heating strips is 24V~36V, and the rated power is 50W / m~100W / m, which is suitable for the safe use requirements of buried cables, and can also quickly heat and melt the phase change filler material.
[0015] The technical effects and advantages of this invention are as follows: This solution abandons rigid steel tape armor and adopts flexible fiberglass wrapping tape combined with high-strength phase change filler material. After solidification, the phase change filler material combines with the fiberglass to form high-strength protection. At the same time, the arch bridge stress structure of the arc splicing strip can withstand strong compressive stress. Combined with the buffering effect of the airbag buffer chamber, it can effectively resolve external frost heave pressure and prevent cable damage. In particular, the flexibility of the cable is better than that of conventional armored cables when the phase change material is molten, which facilitates operation. This solution improves the overall flexibility of the cable while ensuring compressive strength, making it easier to lay out and install on site. Attached Figure Description
[0016] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:
[0017] Figure 1 This is a schematic diagram of the external structure of the present invention; Figure 2 This is a schematic diagram of the antifreeze cable and low-temperature phase change sheath structure of the present invention; Figure 3 This is a schematic diagram of the low-temperature phase change sheath structure of the present invention; Figure 4 This is a schematic diagram of the antifreeze cable structure of the present invention.
[0018] Legend: 1. Antifreeze cable; 2. Low temperature phase change sheath; 3. Arc splicing strip; 4. Phase change chamber; 5. Airbag buffer chamber; 6. Central partition wall; 7. Positioning slot; 8. Heating belt; 9. Insulation cotton; 10. Fiberglass wrapping tape; 11. Conductor core; 12. Conductor insulation layer; 13. Insulating sheath; 14. Filler layer. Detailed Implementation
[0019] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0020] Example 1: Freeze-resistant underground cable with basic phase change sheath: Please refer to Figure 1 - Figure 4 The present invention provides an antifreeze underground cable with a phase change sheath, the cable including an antifreeze cable 1 and a low temperature phase change sheath 2 coaxially wrapped around the outside of the antifreeze cable 1.
[0021] The low-temperature phase change sheath 2 is the core component of this invention. It is composed of multiple sets of arc-shaped splicing strips 3 spliced together. Specifically, the low-temperature phase change sheath 2 is preferably composed of six or more sets of arc-shaped splicing strips 3 interlocked with each other through end fitting structures to form a complete annular sheath structure. This annular sheath structure can coaxially wrap the antifreeze cable 1 inside it, providing comprehensive protection. The number of arc-shaped splicing strips 3 can be adjusted according to the cable diameter and structural strength requirements, but it should be ensured that a stable annular structure is formed after splicing.
[0022] like Figure 3 As shown, the structural design of the arc-shaped splicing strip 3 is key to this invention. A phase change chamber 4 is provided on the inner wall of each arc-shaped splicing strip 3. The phase change chamber 4 is designed as a long, narrow cavity extending along the length of the arc-shaped splicing strip 3, and is filled with a phase change filler material. The phase change temperature of this filler material is set to be higher than 25°C to ensure that the material can undergo phase change and solidify when the ambient temperature is below 25°C, especially near the freezing point, thereby enhancing the cable's compressive strength.
[0023] On the outer wall of the same arc-shaped splice strip 3, an airbag buffer chamber 5 is arranged radially alongside the phase change chamber 4. The presence of the airbag buffer chamber 5 provides additional buffer space for the cable. When the soil around the buried cable freezes and expands, the resulting frost heave pressure will first act on the low-temperature phase change sheath 2. Due to the arched structure of the arc-shaped splice strip 3, the external frost heave pressure can be guided to both sides of the arc-shaped splice strip 3, forming a force-bearing structure similar to an arch bridge, thereby preventing external pressure from directly squeezing the internal anti-freeze cable 1. At the same time, the airbag buffer chamber 5 is filled with air or inert gas, providing a deformable buffer layer. When the ground freezes and expands, the airbag buffer chamber 5 can be compressed, acting like a spring to absorb and disperse the frost heave pressure, effectively relieving external compression and further protecting the anti-freeze cable 1 from damage.
[0024] Furthermore, positioning slots 7 are provided on both ends of the arc-shaped splicing strip 3 along its length. The groove design of the positioning slots 7 is adapted to the cross-sectional shape of the heating band 8, allowing the heating band 8 to be easily fixed in the positioning slots 7. The heating band 8 provides active heating capability for the cable. When the ambient temperature is too low, the phase change material is completely solidified, and its heat release capacity is insufficient, the heating band 8 can be activated to heat the phase change filler material, causing it to melt and release latent heat, thereby rapidly increasing the temperature around the cable and preventing freezing damage. Most importantly, during cable laying in winter, the phase change filler material can be melted by heating, making the cable more flexible and easier to lay. At the same time, the heating band 8, fixed in the positioning slots 7, can position and limit the arc-shaped splicing strip 3, effectively preventing loosening and displacement after multiple sets of arc-shaped splicing strips 3 are spliced, thus enhancing the structural stability of the entire low-temperature phase change sheath 2.
[0025] On the outside of the low-temperature phase change sheath 2, a layer of thermal insulation cotton 9 is completely covered. The thermal insulation cotton 9 is made of a material with low thermal conductivity, such as rock wool, glass wool or polyester fiber, which is designed to reduce the rate of heat loss to the surrounding soil. This layer of thermal insulation cotton 9 can effectively slow down the conduction of heat released by the phase change filling material or heat generated by the heating belt 8 to the external environment, prolong the time for the phase change material to play its role, and improve the overall thermal insulation effect and energy utilization efficiency.
[0026] On the outside of the insulation cotton 9, a layer of fiberglass wrapping tape 10 is evenly wrapped around its circumference to form a puncture-resistant and corrosion-resistant protective layer. Traditional cable armor usually uses steel tape, but this invention achieves protection through fiberglass wrapping tape 10. The fiberglass wrapping tape 10 is woven from high-strength glass fiber and has excellent tensile strength, puncture resistance, and corrosion resistance. It can effectively resist the erosion of cables by sharp objects or chemicals in the soil, while avoiding the increased rigidity and weight of traditional steel tape armor, making the cable more flexible and easier to install. This protective layer not only provides physical protection but also forms a comprehensive protection system together with the insulation cotton 9.
[0027] Example 2: Optimization of the structure and phase change filler material of the antifreeze cable 1: Based on Example 1, this example further optimizes the internal structure of the antifreeze cable 1 and the composition of the phase change filler material.
[0028] Please see Figure 4 The antifreeze cable 1 includes a conductor core 11 for transmitting current. The conductor core 11 is coaxially wrapped with a conductor insulation layer 12, which is responsible for isolating high-voltage current and preventing leakage. The conductor insulation layer 12 is coaxially wrapped with an insulating sheath 13, which serves as a second layer of insulation and protection for the cable. The annular gap between the insulating sheath 13 and the conductor insulation layer 12 is filled with a filler layer 14. The filler layer 14 is preferably made of a soft and elastic polymer material, such as cross-linked polyethylene or EPDM rubber. The filler layer 14 is mainly used to fill the gap and fix the conductor insulation layer 12, ensuring that the conductor insulation layer 12 remains stable when the cable is bent or under stress, preventing displacement. At the same time, the filler layer 14 can also help improve the overall tensile and compressive strength of the antifreeze cable 1, so that it can maintain structural integrity in deeper and more complex underground environments.
[0029] The phase change chamber 4 is uniformly filled with chopped glass fibers as a reinforcing phase component, in addition to the phase change filler material. The chopped glass fibers and the phase change filler material are thoroughly mixed during the preparation process to form a homogeneous composite system. This composite system enhances the structural strength and durability of the phase change filler material. When the phase change filler material is in a solidified state, the chopped glass fibers act like reinforcing bars in reinforced concrete, providing skeletal support and significantly improving the tensile, compressive strength, and toughness of the material. This effectively prevents cracking and detachment of the phase change filler material under long-term thermal cycling or external extrusion, ensuring the stability of the phase change function.
[0030] Preferably, the phase change filler material is a phase change composite system formed by compounding polyethylene glycol and paraffin wax, wherein the mass percentage of polyethylene glycol is 65%–80%, the mass percentage of paraffin wax is 20%–35%, and the sum of the mass percentages of polyethylene glycol and paraffin wax is 100%. By precisely controlling the ratio of the two, the phase change temperature of this composite system can be precisely controlled within 28℃~32℃. This phase change temperature range is carefully designed to well adapt to the temperature variation requirements of buried environments. In most cold regions of my country, the underground soil temperature is often below 0℃ in winter. However, due to geothermal energy and the soil's own heat insulation effect, the temperature of deep soil usually does not drop to extremely low levels. A phase change temperature of 28℃~32℃ means that the material will continuously release latent heat when the ambient temperature is much lower than this value, effectively buffering temperature changes, ensuring stable operation of the phase change function, preventing the cable from reaching its freezing point, and also ensuring that the phase change filler material is in a solidified state in most cases.
[0031] To further improve the long-term stability of the phase change filler, an antioxidant with a mass ratio of 1% to 3% is added to the phase change filler, preferably 2,6-di-tert-butyl-p-cresol. This antioxidant can be uniformly dispersed in the phase change filler, effectively capturing free radicals and delaying the oxidative degradation reaction of the phase change filler under long-term thermal cycling conditions. Frequent and prolonged phase change processes and temperature fluctuations can lead to material aging and deterioration, reducing phase change performance. Adding an antioxidant can significantly extend the service life of the phase change filler, ensure the long-term stability of the phase change protection function, and reduce maintenance costs.
[0032] The chopped glass fibers are preferably 3 mm in length and 20 μm in diameter, and their volume fraction in the phase change chamber 4 is 5% to 10%. This size and proportion of chopped glass fibers can form a uniformly dispersed reinforcing network in the phase change filler material. After the phase change filler material solidifies, this reinforcing network can effectively improve its compressive strength and structural stability, enabling it to better withstand external frost heave pressure, prevent the phase change material from cracking due to stress concentration, and ensure its integrity and functionality under extreme conditions.
[0033] Example 3: Refined design of airbag buffer chamber and heating band: Based on Examples 1 and 2, this example further optimizes the structure and parameters of airbag buffer chamber and heating band.
[0034] Please see Figure 3 The airbag buffer chamber 5 has an integrally formed central partition wall 6, which extends radially along the arc-shaped splicing strip 3, uniformly dividing the airbag buffer chamber 5 into two independent buffer chambers. This design has multiple advantages: First, the central partition wall 6 can significantly enhance the structural rigidity of the airbag buffer chamber 5, preventing it from excessively deforming or collapsing under large pressure. Second, by dividing the buffer chamber into independent parts, the buffering force can be more evenly distributed when subjected to local frost heave pressure, avoiding excessive stress at a single point that could lead to buffer failure. This further improves the buffering effect against external frost heave pressure and more effectively protects the cable.
[0035] The heating band 8 is internally embedded with a nickel-chromium alloy heating core, which is the core heating component of the heating band 8. This core possesses excellent electrothermal conversion efficiency and high-temperature resistance. The nickel-chromium alloy heating core is externally covered with a layer of Teflon high-temperature cloth. Teflon has excellent high-temperature resistance, corrosion resistance, and insulation properties. A fiberglass cloth serves as an insulating substrate between the Teflon high-temperature cloth and the nickel-chromium alloy heating core. This insulating substrate provides insulation protection for the nickel-chromium alloy heating core, effectively preventing leakage and ensuring safe use. Furthermore, the combination of the fiberglass cloth and the Teflon high-temperature cloth further enhances the high-temperature resistance of the heating band 8, making it less prone to damage during prolonged operation or high-power heating.
[0036] The fiberglass wrapping tape 10 is woven from alkali-free fiberglass yarn, which features high strength, corrosion resistance, and good electrical insulation. Its wrapping overlap rate is 30%, and the wrapping thickness is 50%, ensuring a seamless and complete wrapping layer, forming a dense protective layer. The wrapping thickness is 2mm-5mm, ensuring sufficient mechanical protection without significantly increasing the overall diameter of the cable. The outer surface of the fiberglass wrapping tape 10 is coated with a polyvinyl chloride (PVC) anti-corrosion coating. This coating significantly enhances the puncture resistance and corrosion resistance of the fiberglass wrapping tape 10. The PVC coating has excellent acid and alkali resistance, oil resistance, and moisture resistance, effectively resisting complex soil chemical erosion in buried environments and improving its resistance to soil erosion, enabling it to be used stably and normally in complex buried soil environments and under long-term buried conditions.
[0037] The heating bands 8 are continuously arranged along the length of the arc-shaped splicing strips 3, and the ends of the heating bands 8 on adjacent sets of arc-shaped splicing strips 3 are detachably electrically connected via conductive terminals. This ensures that multiple sets of heating bands 8 can form a complete heating circuit, achieving uniform heating of the entire low-temperature phase change sheath 2. The rated voltage of the heating bands 8 is preferably 24V and 50W / m, which can provide sufficient heating power while ensuring safety, quickly melting the phase change filling material. This detachable electrical connection method also facilitates installation and subsequent maintenance and replacement.
[0038] The above are merely embodiments of this application and are not intended to limit the scope of protection of 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 scope of protection of this application.
Claims
1. A freeze-resistant underground cable with a phase-change sheath, characterized in that, The system includes an antifreeze cable and a low-temperature phase change sheath coaxially wrapped around the outside of the antifreeze cable. The low-temperature phase change sheath is composed of six or more sets of arc-shaped splicing strips. Multiple sets of these arc-shaped splicing strips interlock with each other through end-fitting structures, forming a complete annular sheath structure that coaxially encloses the antifreeze cable within it. The inner wall of each arc-shaped splicing strip has a phase change chamber, which is a long, narrow cavity extending along the length of the arc-shaped splicing strip. The cavity is filled with a phase change filler material. The phase change temperature of the material is higher than 25℃; an airbag buffer chamber is provided on the outer wall of the arc-shaped splicing strip, and the airbag buffer chamber and the phase change chamber are arranged side by side along the radial direction of the arc-shaped splicing strip; positioning slots are provided at both ends of the arc-shaped splicing strip along its length, and the groove shape of the positioning slot is adapted to the cross-sectional shape of the heating belt, and the heating belt is fixed in the positioning slot; the outer side of the low-temperature phase change sheath is entirely covered with a layer of heat insulation cotton, and glass fiber wrapping tape is evenly wrapped around the outer side of the heat insulation cotton along its circumference.
2. The frost-resistant underground cable with a phase change sheath according to claim 1, characterized in that, The antifreeze cable includes a conductor core, a conductor insulation layer coaxially wrapped around the outside of the conductor core, an insulating sheath coaxially wrapped around the outside of the conductor insulation layer, and a filler layer filling the annular gap between the insulating sheath and the conductor insulation layer.
3. The frost-resistant buried cable with a phase change sheath according to claim 1, characterized in that, In addition to the phase change filling material, the phase change chamber is also uniformly filled with chopped glass fibers as a reinforcing phase component. The chopped glass fibers and the phase change filling material are thoroughly mixed to form a uniform composite system.
4. The frost-resistant buried cable with a phase change sheath according to claim 3, characterized in that, The phase change filler material is a phase change composite system formed by compounding polyethylene glycol and paraffin wax, wherein the mass percentage of polyethylene glycol is 65% to 80%, the mass percentage of paraffin wax is 20% to 35%, and the sum of the mass percentages of polyethylene glycol and paraffin wax is 100%; the phase change temperature of the composite system is precisely controlled between 28℃ and 32℃.
5. A freeze-resistant underground cable with a phase-change sheath according to claim 4, characterized in that, The phase change filler material also contains an antioxidant at a mass ratio of 1% to 3%, specifically 2,6-di-tert-butyl-p-cresol.
6. The frost-resistant buried cable with a phase change sheath according to claim 3, characterized in that, The chopped glass fibers have a length of 3mm to 8mm and a diameter of 10μm to 20μm, and their volume percentage in the phase change chamber is 5% to 10%.
7. The frost-resistant underground cable with a phase-change sheath according to claim 1, characterized in that, The airbag buffer chamber is integrally formed with a central partition wall, which extends radially along the arc-shaped splicing strip, uniformly dividing the airbag buffer chamber into two independent buffer chambers.
8. A freeze-resistant underground cable with a phase change sheath according to claim 1, characterized in that, The heating band is embedded with a nickel-chromium alloy heating core, which is covered with a layer of Teflon high-temperature cloth. Glass fiber cloth is filled between the Teflon high-temperature cloth and the nickel-chromium alloy heating core as an insulating substrate.
9. A freeze-resistant underground cable with a phase change sheath according to claim 1, characterized in that, The fiberglass wrapping tape is woven from alkali-free fiberglass yarn, and the outer surface of the fiberglass wrapping tape is coated with a layer of polyvinyl chloride anti-corrosion coating.
10. A freeze-resistant underground cable with a phase-change sheath according to claim 1, characterized in that, The heating bands are continuously laid out along the length of the arc-shaped splicing strips, and the ends of the heating bands on two adjacent sets of arc-shaped splicing strips are detachably electrically connected through conductive terminals to ensure that multiple sets of heating bands form a complete heating circuit.