Prefabricated directly-buried thermal insulation pipe

Abstract

The prefabricated directly-buried thermal insulation pipe comprises an inner working steel pipe, buffer rods, a thermal insulation layer, a reinforcing support and an outer protection steel pipe, the outer side of the inner working steel pipe is sleeved with a positioning sleeve A, and the buffer rods are evenly distributed and installed between the inner working steel pipe and the positioning sleeve A along the outer side of the inner working steel pipe; a buffer heat insulation cavity is formed between the inner working steel pipe and the positioning sleeve A, the buffer heat insulation cavity is filled with inert gas, the positioning sleeve A is sleeved with a positioning sleeve B, a heat preservation layer is arranged between the positioning sleeve A and the positioning sleeve B, a protruding point A is arranged on the outer surface of the positioning sleeve A, and a protruding point B is arranged on the inner surface of the positioning sleeve B. Displacement and stress generated by temperature changes of the inner working steel pipe are effectively counteracted, the situation that the overall heat preservation effect is affected due to the fact that the heat preservation layer directly bears pressure and is damaged is avoided, the anti-extrusion capacity of the pipeline is further improved, and the service life of the prefabricated directly-buried heat preservation pipe is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of prefabricated direct-buried insulated pipes, specifically a type of prefabricated direct-buried insulated pipe. Background Technology

[0002] Pre-insulated direct-buried pipes feature a rigid polyurethane foam insulation layer tightly bonded to the outer surface of the steel pipe, effectively preventing air and water penetration and providing excellent corrosion protection. Furthermore, its closed-cell structure minimizes water absorption. The high-density polyethylene and fiberglass outer shells offer superior corrosion resistance, insulation, and mechanical properties. Therefore, the outer surface of the working steel pipe is highly resistant to corrosion from external air and water. Provided the internal water quality is properly treated, according to foreign data, high-temperature pre-insulated direct-buried pipes can have a service life exceeding 50 years, 3-4 times longer than traditional trench or overhead installations. Pre-insulated direct-buried pipes are widely used in liquid and gas transmission networks, chemical pipeline insulation projects, petroleum, chemical, district heating networks, central air conditioning ventilation ducts, and municipal engineering projects.

[0003] The existing equipment has the following shortcomings when in use: Disadvantages: During the long-term transportation of high-temperature media, the working steel pipe is prone to displacement and stress due to thermal expansion and contraction, which can lead to damage to the insulation layer and affect the overall insulation effect. At the same time, the reinforcement structure of the prefabricated direct-buried insulation pipe is simple and is prone to structural deformation when subjected to external soil pressure or construction impact, which reduces the overall load-bearing capacity and service life of the pipeline. Summary of the Invention

[0004] The purpose of this invention is to provide a prefabricated direct-buried insulated pipe to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a prefabricated direct-buried insulated pipe, comprising an inner working steel pipe, buffer rods, an insulation layer, a reinforcing bracket, and an outer protective steel pipe. A positioning sleeve A is fitted onto the outer side of the inner working steel pipe. Buffer rods are evenly distributed along the outer side of the inner working steel pipe between the inner working steel pipe and the positioning sleeve A, forming a buffer insulation cavity between the inner working steel pipe and the positioning sleeve A. The buffer insulation cavity is filled with inert gas. A positioning sleeve B is fitted onto the outer side of the positioning sleeve A. An insulation layer is provided between the positioning sleeve A and the positioning sleeve B. A protrusion A is provided on the outer surface of the positioning sleeve A, and a protrusion B is provided on the inner surface of the positioning sleeve B.

[0006] By adopting the above technical solution, a buffer rod and a buffer insulation cavity are set between the inner working steel pipe and the positioning sleeve A. The buffer rods, which are evenly distributed along the outer side of the inner working steel pipe, can effectively disperse the radial stress generated by the thermal expansion and contraction of the inner working steel pipe. In conjunction with the inert gas filled in the buffer insulation cavity, the low thermal conductivity of the inert gas is used to further improve the overall insulation performance. At the same time, the compressibility of the gas can further enhance the buffering effect, effectively offsetting the displacement and stress of the inner working steel pipe caused by temperature changes, and avoiding the insulation layer from being directly subjected to pressure and damaged, thus affecting the overall insulation effect. In addition, the protrusion A set on the outer surface of the positioning sleeve A and the protrusion B set on the inner surface of the positioning sleeve B increase the friction with the insulation layer, making it less likely for the insulation layer to slide relative to the insulation layer during pipeline operation, thus ensuring the stability of the insulation structure.

[0007] Preferably, the buffer rod includes a slide rod, a sleeve rod, and a spring. One end of the slide rod is fixedly connected to the outer wall of the inner working steel pipe, and the other end is movably inserted into the inside of the sleeve rod. One end of the sleeve rod is fixedly connected to the inner wall of the positioning sleeve A. The spring is sleeved on the outside of the slide rod and the sleeve rod, and both ends of the spring are respectively connected to the outer side of the inner working steel pipe and the inner side of the positioning sleeve A.

[0008] Using the above technical solution, when the inner working steel pipe expands or contracts due to temperature changes, the sliding rod can slide within the sleeve rod, and the spring extends and retracts accordingly, converting the concentrated stress into elastic potential energy and gradually releasing it, thereby avoiding rigid collisions between the inner working steel pipe and the positioning sleeve A. The inert gas filled in the buffer insulation cavity not only has a low thermal conductivity, reducing heat transfer through air convection, but its compressibility also works in conjunction with the elasticity of the buffer rod to jointly enhance the buffer insulation effect, further ensuring the structural stability of the inner working steel pipe during temperature cycling.

[0009] Preferably, an outer protective steel pipe is fitted around the positioning sleeve B, and a reinforcing bracket is provided between the positioning sleeve B and the outer protective steel pipe, with the reinforcing bracket evenly distributed along the circumference of the positioning sleeve B.

[0010] By adopting the above technical solution, the reinforcing support set between the positioning sleeve B and the outer protective steel pipe can significantly improve the overall structural strength of the pipeline. Its design of being evenly distributed around the circumference of the positioning sleeve B further ensures the stability and safety of the entire pipeline structure and effectively extends the service life of the prefabricated direct-buried insulated pipe.

[0011] Preferably, an airbag is provided in the outer protective layer formed between the positioning sleeve B and the outer protective steel pipe, and the airbag is evenly distributed along the inner sidewall of the outer protective steel pipe.

[0012] By adopting the above technical solution, by setting evenly distributed airbags in the outer protective layer between the positioning sleeve B and the outer protective steel pipe, the airbags can absorb the impact force through their own elastic deformation when the pipeline is subjected to external soil pressure or construction impact. The airbags and the reinforcing support work together to improve the pipeline's resistance to compression while preventing the outer protective steel pipe from denting or deforming due to excessive local stress, thus further enhancing the adaptability of the prefabricated direct-buried insulated pipe in complex underground environments.

[0013] Preferably, the outer protective steel pipe is coated with an anti-corrosion layer.

[0014] Using the above technical solution, the anti-corrosion layer is made of epoxy coal tar coating and fiberglass cloth, which has excellent chemical corrosion resistance, soil corrosion resistance and anti-aging properties. It can effectively block the erosion of steel pipes by groundwater, corrosive ions in the soil and microorganisms, significantly extend the service life of the outer protective steel pipe, and ensure the structural integrity and safety of the entire prefabricated direct-buried insulated pipe system in the long-term buried environment.

[0015] Preferably, the cross-section of the reinforcing bracket is an X-shaped structure.

[0016] By adopting the above technical solution, this X-shaped structure design can distribute external pressure to multiple directions. Compared with the traditional straight support, it has higher bending strength and load-bearing capacity, further enhancing the support stability of the pipeline.

[0017] Compared with the prior art, the beneficial effects of the present invention are: By setting a buffer rod and a buffer insulation cavity between the inner working steel pipe and the positioning sleeve A, when the inner working steel pipe expands or contracts due to temperature changes, the sliding rod can slide inside the sleeve rod, and the spring extends and retracts accordingly, converting the concentrated stress into elastic potential energy and gradually releasing it. This avoids rigid collisions between the inner working steel pipe and the positioning sleeve A. In conjunction with the inert gas filled in the buffer insulation cavity, the low thermal conductivity of the inert gas further enhances the overall insulation performance. At the same time, the compressibility of the gas further enhances the buffering effect, effectively offsetting the displacement and stress of the inner working steel pipe caused by temperature changes, and preventing the insulation layer from being directly subjected to pressure and damaged, thus affecting the overall insulation effect.

[0018] The reinforcing support installed between the positioning sleeve B and the outer protective steel pipe can significantly improve the overall structural strength of the pipeline. Its design, which is evenly distributed around the circumference of the positioning sleeve B, further ensures the stability and safety of the entire pipeline structure. In conjunction with the evenly distributed airbags in the outer protective layer between the positioning sleeve B and the outer protective steel pipe, the airbags can absorb the impact force through their own elastic deformation when the pipeline is subjected to external soil pressure or construction impact. This prevents the outer protective steel pipe from denting or deforming due to excessive local stress, further enhancing the adaptability of the prefabricated direct-buried insulated pipe in complex underground environments and effectively extending the service life of the prefabricated direct-buried insulated pipe. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional structural diagram of the present invention; Figure 3 This is a schematic diagram of the structure of the buffer rod of the present invention; In the diagram: 1. Inner working steel pipe; 2. Buffer insulation cavity; 3. Positioning sleeve A; 4. Buffer rod; 5. Protrusion A; 6. Positioning sleeve B; 7. Protrusion B; 8. Insulation layer; 9. Reinforcing bracket; 10. Outer protective layer; 11. Airbag; 12. Outer protective steel pipe; 13. Anti-corrosion layer; 14. Sliding rod; 15. Sleeve rod; 16. Spring. Detailed Implementation

[0020] Please see Figure 1-3The present invention provides an embodiment of a prefabricated direct-buried insulated pipe, comprising an inner working steel pipe, buffer rods, an insulation layer, a reinforcing bracket, and an outer protective steel pipe. A positioning sleeve A is fitted onto the outer side of the inner working steel pipe. Buffer rods are evenly distributed along the outer side of the inner working steel pipe between the inner working steel pipe and the positioning sleeve A, forming a buffer insulation cavity. The buffer insulation cavity is filled with inert gas. A positioning sleeve B is fitted onto the outer side of the positioning sleeve A. An insulation layer is provided between the positioning sleeve A and the positioning sleeve B. The outer surface of the positioning sleeve A has protrusions A, and the inner surface of the positioning sleeve B has protrusions B. By setting buffer rods and a buffer insulation cavity between the inner working steel pipe and the positioning sleeve A, the buffer rods, which are evenly distributed along the outer side of the inner working steel pipe, can effectively disperse the radial stress generated by the thermal expansion and contraction of the inner working steel pipe. In conjunction with the inert gas filled in the buffer insulation cavity, the low thermal conductivity of the inert gas further enhances the overall insulation performance. At the same time, the compressibility of the gas further enhances the buffering effect, effectively offsetting the displacement and stress of the inner working steel pipe caused by temperature changes, and preventing the insulation layer from being directly subjected to pressure and damaged, thus affecting the overall insulation effect. In addition, the protrusion A on the outer surface of the positioning sleeve A and the protrusion B on the inner surface of the positioning sleeve B increase the friction with the insulation layer, making it less likely for the insulation layer to slide relative to the insulation layer during pipeline operation, thus ensuring the stability of the insulation structure.

[0021] The buffer rod includes a sliding rod, a sleeve rod, and a spring. One end of the sliding rod is fixedly connected to the outer wall of the inner working steel pipe, and the other end is movably inserted into the sleeve rod. One end of the sleeve rod is fixedly connected to the inner wall of the positioning sleeve A. The spring is sleeved on the outside of the sliding rod and the sleeve rod, and its two ends are respectively connected to the outer side of the inner working steel pipe and the inner side of the positioning sleeve A. When the inner working steel pipe expands or contracts due to temperature changes, the sliding rod can slide inside the sleeve rod, and the spring extends and retracts accordingly, converting the concentrated stress into elastic potential energy and gradually releasing it, thereby avoiding rigid collisions between the inner working steel pipe and the positioning sleeve A. The inert gas filled in the buffer insulation cavity not only has a low thermal conductivity, reducing heat transfer through air convection, but its compressibility also works in conjunction with the elasticity of the buffer rod to enhance the buffer insulation effect, further ensuring the structural stability of the inner working steel pipe during temperature cycling.

[0022] The positioning sleeve B is fitted with an outer protective steel pipe, and a reinforcing bracket is provided between the positioning sleeve B and the outer protective steel pipe. The reinforcing bracket is evenly distributed along the circumference of the positioning sleeve B. The reinforcing bracket between the positioning sleeve B and the outer protective steel pipe can significantly improve the overall structural strength of the pipeline. Its even distribution along the circumference of the positioning sleeve B further ensures the stability and safety of the entire pipeline structure, effectively extending the service life of the prefabricated direct-buried insulated pipe.

[0023] An airbag is installed in the outer protective layer formed between the positioning sleeve B and the outer protective steel pipe. The airbags are evenly distributed along the inner wall of the outer protective steel pipe. By installing evenly distributed airbags in the outer protective layer between the positioning sleeve B and the outer protective steel pipe, the airbags can absorb the impact force through their elastic deformation when the pipeline is subjected to external soil pressure or construction impact. The airbags and the reinforcing support work together to improve the pipeline's resistance to compression while preventing the outer protective steel pipe from denting or deforming due to excessive local stress, further enhancing the adaptability of the prefabricated direct-buried insulated pipe in complex underground environments.

[0024] The outer protective steel pipe is coated with an anti-corrosion layer. This anti-corrosion layer is made of epoxy coal tar coating and fiberglass cloth, which has excellent chemical corrosion resistance, soil corrosion resistance and aging resistance. It can effectively block the erosion of the steel pipe by groundwater, corrosive ions in the soil and microorganisms, significantly extend the service life of the outer protective steel pipe, and ensure the structural integrity and safety of the entire prefabricated direct-buried insulated pipe system in long-term buried environments.

[0025] The reinforced support has an X-shaped cross-section. This X-shaped design can distribute external pressure in multiple directions, and compared with the traditional straight support, it has higher bending strength and load-bearing capacity, further improving the stability of the reinforced support for the pipeline.

Claims

1. A prefabricated direct-buried insulated pipe, comprising an inner working steel pipe (1), a buffer rod (4), an insulation layer (8), a reinforcing support (9), and an outer protective steel pipe (12), characterized in that: The inner working steel pipe (1) is fitted with a positioning sleeve A (3) on its outer side. Buffer rods (4) are evenly distributed along the outer side of the inner working steel pipe (1) between the inner working steel pipe (1) and the positioning sleeve A (3). A buffer heat insulation cavity (2) is formed between the inner working steel pipe (1) and the positioning sleeve A (3). The buffer heat insulation cavity (2) is filled with inert gas. A positioning sleeve B (6) is fitted on the outside of the positioning sleeve A (3). A heat insulation layer (8) is provided between the positioning sleeve A (3) and the positioning sleeve B (6). A protrusion A (5) is provided on the outer surface of the positioning sleeve A (3). A protrusion B (7) is provided on the inner surface of the positioning sleeve B (6).

2. The prefabricated direct-buried insulated pipe according to claim 1, characterized in that: The buffer rod (4) includes a slide rod (14), a sleeve rod (15) and a spring (16). One end of the slide rod (14) is fixedly connected to the outer wall of the inner working steel pipe (1), and the other end is movably inserted into the inside of the sleeve rod (15). One end of the sleeve rod (15) is fixedly connected to the inner wall of the positioning sleeve A (3). The spring (16) is sleeved on the outside of the slide rod (14) and the sleeve rod (15), and the two ends of the spring (16) are respectively connected to the outer side of the inner working steel pipe (1) and the inner side of the positioning sleeve A (3). A prefabricated direct-buried insulated pipe according to claim 1, characterized in that: The positioning sleeve B (6) is covered with an outer protective steel pipe (12), and a reinforcing bracket (9) is provided between the positioning sleeve B (6) and the outer protective steel pipe (12). The reinforcing bracket (9) is evenly distributed along the circumference of the positioning sleeve B (6). A prefabricated direct-buried insulated pipe according to claim 1, characterized in that: An airbag (11) is provided in the outer protective layer (10) formed between the positioning sleeve B (6) and the outer protective steel pipe (12), and the airbag (11) is evenly distributed along the inner side wall of the outer protective steel pipe (12). A prefabricated direct-buried insulated pipe according to claim 1, characterized in that: The outer protective steel pipe (12) is coated with an anti-corrosion layer (13). A prefabricated direct-buried insulated pipe according to claim 1, characterized in that: The cross-section of the reinforcing bracket (9) is an X-shaped structure.

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