Polar region double-layer heat insulation living water conveying pipeline and assembling process thereof

Abstract

The invention belongs to the technical field of conveying pipelines, and particularly relates to a polar region double-layer heat insulation living water conveying pipeline and an assembling technology thereof.The polar region double-layer heat insulation living water conveying pipeline comprises a plurality of sections, a stainless steel sleeve and a double-end internal thread connector, each section comprises an inner pipe section and an outer pipe section, the inner pipe section is arranged in the outer pipe section, and the stainless steel sleeve is arranged in the outer pipe section; the inner pipe section comprises a main acting section and external thread connectors located on the two sides of the main acting section respectively, the two external thread connectors extend out of the two ends of the outer pipe section respectively, and the external thread connectors, close to each other, of the two splicing sections are connected together through the same double-end internal thread connector to form a transition splicing section; the stainless steel sleeve can be sleeved and fixed outside the transition splicing section; by adopting the process to splice the conveying pipeline, the process is simple and rapid, the time for workers to stay in extremely severe weather during assembly is shortened, the energy consumed by splicing is very small, and the polar region environment is basically not polluted.

Description

Technical Field

[0001] The invention relates to the technical field of transportation pipelines, and in particular to a polar double-layer insulated domestic water transportation pipeline and an assembly process thereof. Background Art

[0002] Surveys and observational monitoring of marine ecology, sea ice, glaciers, sea level, atmosphere, geophysics, high-altitude atmospheric physics, terrestrial ecology, land and marine geology, and birds in the Antarctic region will provide basic support for assessing the Antarctic ecological environment and climate change; and will be of extraordinary value for understanding the global system and the impact of climate change.

[0003] my country is one of the few countries in the world that can independently carry out scientific research in the polar regions, establish scientific research stations, and conduct continuous scientific observations. In order to ensure that scientific researchers can study seawater in the scientific research stations around the clock without having to go to the coast to collect water, a seawater sampling and transportation pipeline system for automatically transporting seawater has become indispensable.

[0004] However, due to the harsh polar environment, poor construction conditions, and various international treaties with high requirements for Antarctic environmental protection, it is also required that the connection of pipelines should be as simple, fast, reliable, clean and environmentally friendly as possible. The conventional connection methods are welding and bonding. Due to the high temperature requirements during welding, welding cannot be performed at low temperatures, and there is a shortage of polar welding equipment and energy. In addition, welding will produce welding exhaust gas and dust, and the method of bonding pipelines will cause the glue to evaporate into the atmosphere, which is not conducive to environmental protection. In addition, the Antarctic environment is relatively cold, and seawater samples are more likely to leak heat when they are taken from the sea and transported in pipelines, especially at the joints of the pipelines. In extreme weather, the seawater is easily frozen, affecting transportation and research. Summary of the invention

[0005] Therefore, the problem of the existing technology is that the existing medium transport pipelines are prone to heat leakage at the splicing points and have poor insulation effect, which is not conducive to transporting seawater samples that need to be studied in the polar regions. Moreover, the existing pipelines are not only time-consuming and labor-intensive to splice, but also require a lot of energy and cause great pollution to the environment.

[0006] In order to solve the above technical problems, the present invention provides a polar double-layer insulated domestic water delivery pipeline, comprising a plurality of segments, a stainless steel casing, a polyurethane foam, a polyurethane tube shell and a double-headed internal thread joint, each of the segments comprising an inner tube segment and an outer tube segment, the inner tube segment and the outer tube segment are concentrically arranged, the inner tube segment is arranged in the outer tube segment, the inner tube segment comprises a main action segment and external thread joints respectively located on both sides of the main action segment, and the length of the main action segment is consistent with the length of the outer tube segment, the two external thread joints respectively extend out of the two ends of the outer tube segment, the adjacent spliced ​​segments are called the first segment and the second segment, the first segment comprises a first external thread joint and a first outer tube segment, the second segment comprises a second external thread joint and a second outer tube segment, the first external thread joint and the second external thread joint close to each other are connected together by the same double-headed internal thread joint to form a transition splicing segment; The ends of the first outer tube section and the second outer tube section adjacent to each other are respectively called the first end and the second end, and the two ends of the stainless steel sleeve are respectively sleeved and fixed outside the first end and the second end; The polyurethane shell is sleeved and fixed on the outside of the inner tube section, and the outer tube section is sleeved and fixed on the outside of the polyurethane shell; An annular cavity is provided between the stainless steel sleeve and the transition joint section, and the annular cavity is filled with polyurethane foam.

[0007] Preferably, it also includes an inner tube electric heating tape and an outer tube electric heating tape, wherein the inner tube electric heating tape is laid between the inner tube section and the polyurethane tube shell, and the outer tube electric heating tape is laid between the polyurethane tube shell and the outer tube section.

[0008] Preferably, the inner wall surface of the polyurethane tube shell is provided with an inner groove capable of accommodating the inner tube electric heating belt, and the outer wall surface of the polyurethane tube shell is provided with an outer groove capable of accommodating the outer tube electric heating belt.

[0009] Preferably, the inner tube electric heating tape is provided with three, one of which is connected to the power supply, and the inner groove is also provided with three, each of which accommodates one of the inner tube electric heating tape; the outer tube electric heating tape is provided with three, one of which is connected to the power supply, and the outer groove is also provided with three, each of which accommodates one of the outer tube electric heating tape.

[0010] Preferably, the inner tube electric heating cables on two adjacent segments are electrically connected together through a first junction box, and the outer tube electric heating cables on two adjacent segments are electrically connected together through a second junction box.

[0011] The present invention also provides an assembly process for a polar double-layer insulated domestic water delivery pipeline, comprising the following steps: S1. Assemble two external threaded joints on both sides of the main action section on a special assembly platform, and weld them using an automatic argon arc welding machine according to the corresponding welding process regulations; S2. Inner pipe section sealing and pressure test: Use a double-ended internal thread joint and a nut plug to connect the inner pipe section to be tested, and connect the pressure gauge, stop valve, hose and pressure test pump in sequence; The conditions and process of pressure testing of inner pipe section: a. The inner pipe section is welded according to the design requirements, and the welds are qualified after on-site inspection; b. The test medium that meets the requirements has been prepared; the hydraulic medium is clean fresh water, and the chloride ion content in the water does not exceed 30ppm; c. The pressure gauge used in the test has been calibrated and qualified (the calibration date is valid during the test period), the accuracy of the pressure gauge is not less than Class 1.5, the full scale value of the gauge is 1.5 to 2 times the maximum measured pressure, and there are no less than two pressure gauges; d. Use compressed air to remove dust and debris in the pipe before testing; use a cloth to clean it if necessary; e. When the ambient temperature of the test site is below 5°C, anti-freezing measures must be taken; f. If there is no abnormality in the water injection inspection, the pressure can be increased. The pressure increase process should be slow and steady. First, the pressure is increased to 0.5MPa, and a comprehensive inspection of the pipeline system is carried out. If there is a problem, the pressure should be released and repaired. It is strictly forbidden to repair under pressure. If there is no abnormality, continue to increase the pressure, first increase it to 25%, 50%, and 75% of the test pressure in sequence, and maintain the pressure for 10 minutes in each step, and finally increase it to the test pressure; g. After the pressure test is qualified, the test medium should be discharged at a suitable location outdoors and pay attention to safety; h. After the pressure test is completed, all temporary devices should be removed in time, the records should be checked, and the "Water Pressure Test Record" should be filled in; S3. Lay the inner pipe electric heating cable outside the inner pipe section according to the drawing requirements, and then lay the polyurethane shell on the outside. The inner pipe electric heating cable needs to extend part of the end of the polyurethane shell so as to be spliced ​​with the inner pipe electric heating cable of other sections on site; S4. Open an outer groove on the outer wall of the polyurethane shell, and then lay the outer tube electric heating cable on the outer wall of the polyurethane shell. The outer tube electric heating cable needs to extend a portion of the end of the polyurethane shell so as to be spliced ​​with the outer tube electric heating cable of other sections on site; S5. Use special pipe threading equipment to put the outer pipe section on the outside of the polyurethane pipe shell and the outer pipe electric heating cable. Be careful not to damage the polyurethane pipe shell and the outer pipe electric heating cable when threading the pipe; S6. Pre-install the stainless steel casing on the segment; S7. Use the same double-ended internal thread joint to thread the first external thread joint and the second external thread joint on the two inner pipe sections to be spliced ​​together, thereby splicing the two inner pipe sections together; S8. Use a first junction box to electrically connect the inner tube electric heating tapes of two adjacent segments extending from the ends of their respective polyurethane shells; use a second junction box to electrically connect the outer tube electric heating tapes of two adjacent segments extending from the ends of their respective polyurethane shells; S9. Polar on-site splicing: Fill the polyurethane foam into the stainless steel casing installed on the segment, move the stainless steel casing together with the polyurethane foam to the transition splicing section, and then apply epoxy glue in the gap between the stainless steel casing and the outer pipe section, so that the two ends of the stainless steel casing are respectively bonded to the outside of the two ends of the outer pipe section, thereby sealing the transition splicing section.

[0012] The technical solution of the present invention has the following beneficial effects: The present invention provides a polar double-layer insulated domestic water delivery pipeline, comprising a plurality of segments, a stainless steel casing, polyurethane foam and a polyurethane pipe shell, each segment comprising an inner pipe segment and an outer pipe segment, the inner pipe segment being arranged inside the outer pipe segment, each inner pipe segment comprising two external threaded joints and a main action segment, the two external threaded joints being respectively located at both sides of the main action segment, and the two segments spliced ​​together are called a first segment and a second segment; The external threaded joint of the inner pipe section of the first section and the external threaded joint of the inner pipe section of the second section are connected to each other, and the two ends of the stainless steel sleeve are respectively sleeved and fixed on the ends of the outer pipe section of the first section and the outer pipe section of the second section that are close to each other, so as to play the role of splicing the two outer pipe sections. In this way, the two sections are spliced ​​together, making the splicing simple and fast, and greatly reducing the time that the installation workers are in a harsh low-temperature environment; The present invention does not require welding or bonding during splicing, thus preventing welding and bonding from causing pollution to the Antarctic environment. The stainless steel casing not only serves to connect the two outer pipe sections, but also acts as a seal to prevent air from entering the joints. The heat is conducted out with the help of air, and the heat is prevented from escaping from the gaps, thus playing a role of heat preservation. There is an annular cavity between the stainless steel casing and the joint, and the annular cavity is filled with polyurethane foam. The polyurethane foam has an extremely low thermal conductivity and good thermal insulation. It can prevent the heat on the joint from being transferred out through the air in the annular cavity, thereby further improving the thermal insulation effect of the joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Explanation of the reference numerals: 1. segment; 11. inner pipe segment; 111. external threaded joint; 112. main working section; 12. outer pipe segment; 2. stainless steel casing; 3. polyurethane foam; 4. polyurethane tube shell; 41. inner groove; 42. outer groove; 5. double-headed inner thread joint; 7. first segment; 71. first external threaded joint; 72. first outer pipe segment; 72a. first end; 8. second segment; 81. second external threaded joint; 82. second outer pipe segment; 82a. second end; 9. annular cavity; 10. inner pipe electric heating tape; 20. outer pipe electric heating tape; 30. first junction box; 40. second junction box.

[0015] Figure 1 A longitudinal cross-sectional view of a single segment of the present invention; Figure 2 It is a longitudinal cross-sectional view of two segments spliced ​​together according to the present invention; Figure 3 is a transverse cross-sectional view of a single segment of the present invention; Figure 4 is a transverse cross-sectional view of the polyurethane tube shell of the present invention; Figure 5 A longitudinal cross-sectional view of two segments of the present invention spliced ​​together (without polyurethane foam filling); Figure 6 It is a schematic diagram of welding two external threaded joints to the inner pipe section of the present invention; Figure 7 It is a schematic diagram of the invention in which multiple inner pipe sections are spliced ​​with double-ended inner thread joints and the ends are sealed with nut plugging tools; Figure 8 It is a schematic diagram of the connection of a pressure gauge, a stop valve, a hose and a pressure pump after a plurality of inner pipe sections of the present invention are spliced ​​and the ends are blocked with a nut plug tool; Fig. 9 It is a schematic diagram of the present invention after laying the inner tube electric heating cable and the polyurethane tube shell; Fig.10 It is a schematic diagram of the present invention after laying the outer pipe electric heating cable; Fig.11 It is a schematic diagram of the present invention after the outer pipe section is installed. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] like Figure 1-Figure 2 As shown, the present invention provides a polar double-layer insulated domestic water delivery pipeline, comprising a plurality of segments 1, a stainless steel casing 2, a polyurethane foam 3 and a polyurethane tube shell 4 and a double-headed internal thread joint 5, each segment 1 comprises an inner pipe segment 11 and an outer pipe segment 12, the inner pipe segment 11 and the outer pipe segment 12 are concentrically arranged, the inner pipe segment 11 is arranged inside the outer pipe segment 12, The inner pipe section 11 includes a main action section 112 and external threaded joints 111 respectively located on both sides of the main action section 112, and the length of the main action section 112 is consistent with the length of the outer pipe section 12, and the two external threaded joints 111 extend out of the two ends of the outer pipe section 12 respectively. The adjacent spliced ​​segments 1 are called the first segment 7 and the second segment 8, the first segment 7 includes a first external threaded joint 71 and a first outer pipe section 72, and the second segment 8 includes a second external threaded joint 81 and a second outer pipe section 82. The first external threaded joint 71 and the second external threaded joint 81 close to each other are connected together by the same double-headed internal thread joint 5 to form a transition splicing section; The ends of the first outer tube section 72 and the second outer tube section 82 adjacent to each other are respectively called the first end 72a and the second end 82a, and the two ends of the stainless steel sleeve 2 are respectively sleeved and fixed outside the first end 72a and the second end 82a; the stainless steel sleeve 2 plays the role of sealing the transition splicing section. First, it can prevent the splicing position from entering the air and allowing the internal heat to be conducted out through the air. Second, it can connect the first outer tube section 72 and the second outer tube section 82.

[0021] like Figure 2 and Fig. 9 As shown, a polyurethane tube shell 4 is fixedly sleeved on the outside of the inner tube section 11, and the outer tube section 12 is sleeved and fixed on the outside of the polyurethane tube shell 4; the main function of the polyurethane tube shell 4 is to play a role in heat insulation to prevent excessive heat loss of the medium in the inner tube section 11.

[0022] like Figure 2 and Figure 5 As shown, there is an annular cavity 9 between the stainless steel sleeve 2 and the transition splicing section, and the annular cavity 9 is filled with polyurethane foam 3. The polyurethane foam 3 has an extremely low thermal conductivity and good thermal insulation, which can prevent the heat on the transition splicing section from being transferred out through the air in the annular cavity 9.

[0023] like Figure 1-Figure 2 As shown, the present invention also includes an inner tube electric heating belt 10 and an outer tube electric heating belt 20. The inner tube electric heating belt 10 is laid between the inner tube section 11 and the polyurethane tube shell 4, and the outer tube electric heating belt 20 is laid between the polyurethane tube shell 4 and the outer tube section 12. The inner tube electric heating belt 10 is turned on when the medium is transported, and the inner tube electric heating belt 10 heats and keeps the medium in the inner tube section 11 warm to prevent the medium from cooling too much during transportation. The outer tube electric heating belt 20 is always turned on to heat the outer tube section 12 to prevent the outer tube section 12 from freezing and making it easy for the medium heat to be conducted out.

[0024] like Figure 3 and Figure 4 As shown, in order to make the inner and outer walls of the polyurethane tube shell 4 have a larger contact area with the inner tube section 11 and the outer tube section 12 respectively, to make the installation more stable, and to prevent the inner tube electric heating belt 10 and the outer tube electric heating belt 20 from being squeezed and damaged, the inner wall surface of the polyurethane tube shell 4 is provided with an inner groove 41 that can accommodate the inner tube electric heating belt 10, and the outer wall surface of the polyurethane tube shell 4 is provided with an outer groove 42 that can accommodate the outer tube electric heating belt 20.

[0025] There are three inner tube electric heating tapes 10, one of which is connected to the power supply, and the other two are spare. If the inner tube electric heating tape 10 in use is damaged, you can choose to connect another inner tube electric heating tape 10 to the power supply, so there are also three inner grooves 41, each inner groove 41 accommodates an inner tube electric heating tape 10; there are three outer tube electric heating tapes 20, one of which is connected to the power supply, and the other two are spare. If the outer tube electric heating tape 20 in use is damaged, you can choose to connect another outer tube electric heating tape 20 to the power supply, so there are also three outer grooves 42, each outer groove 42 accommodates an outer tube electric heating tape 20.

[0026] like Figure 2 As shown, the inner tube electric heating cables 10 on two adjacent segments 1 are electrically connected together through a first junction box 30 , and the outer tube electric heating cables 20 on two adjacent segments 1 are electrically connected together through a second junction box 40 .

[0027] The present invention provides an assembly process for a polar double-layer insulated domestic water delivery pipeline, comprising the following steps: like Figure 6 As shown, S1. The two external threaded joints 111 are assembled on both sides of the main action section 112 on a dedicated assembly platform, and are welded using an automatic argon arc welding machine according to the corresponding welding procedure; like Figure 7 and Figure 8 As shown, S2. Tightness and pressure test of the inner pipe section 11: Use the double-headed internal thread connector 5 and the nut plug fixture to connect the inner pipe section 11 to be tested, and connect the pressure gauge, stop valve, hose and pressure test pump in sequence; The conditions and process for pressure testing of inner pipe section 11: a. The inner pipe section 11 is welded according to the design requirements, and the weld passes the on-site inspection; b. The test medium that meets the requirements has been prepared; the hydraulic medium is clean fresh water, and the chloride ion content in the water does not exceed 30ppm; c. The pressure gauge used in the test has been calibrated and qualified (the calibration date is valid during the test period), the accuracy of the pressure gauge is not less than Class 1.5, the full scale value of the gauge is 1.5 to 2 times the maximum measured pressure, and there are no less than two pressure gauges; d. Use compressed air to remove dust and debris in the pipe before testing; use a cloth to clean it if necessary; e. When the ambient temperature of the test site is below 5°C, anti-freezing measures must be taken; f. If there is no abnormality in the water injection inspection, the pressure can be increased. The pressure increase process should be slow and steady. First, the pressure is increased to 0.5MPa, and a comprehensive inspection of the pipeline system is carried out. If there is a problem, the pressure should be released and repaired. It is strictly forbidden to repair under pressure. If there is no abnormality, continue to increase the pressure, first increase it to 25%, 50%, and 75% of the test pressure in sequence, and maintain the pressure for 10 minutes in each step, and finally increase it to the test pressure; g. After the pressure test is qualified, the test medium should be discharged at a suitable location outdoors and pay attention to safety; h. After the pressure test is completed, all temporary devices should be removed in time, the records should be checked, and the "Water Pressure Test Record" should be filled in; like Fig. 9 As shown, S3. According to the requirements of the drawing, the inner pipe electric heating cable 10 is laid outside the inner pipe section 11, and then the polyurethane shell 4 is laid on the outside. The inner pipe electric heating cable 10 needs to extend out of a part of the end of the polyurethane shell 4 so as to be spliced ​​with the inner pipe electric heating cable 10 of other segments 1 on site; like Fig.10 As shown, S4. An outer groove 42 is formed on the outer wall of the polyurethane shell 4, and then the outer tube electric heating belt 20 is laid on the outer wall of the polyurethane shell 4. The outer tube electric heating belt 20 needs to extend out of a part of the end of the polyurethane shell 4 so as to be spliced ​​with the outer tube electric heating belt 20 of other segments 1 on site; like Fig.11 As shown, S5. Use a special pipe-threading device to set the outer pipe section 12 on the outside of the polyurethane shell 4 and the outer pipe electric heating belt 20. Note that the polyurethane shell 4 and the outer pipe electric heating belt 20 must not be damaged during the pipe threading; S6. Pre-install the stainless steel casing 2 on the segment 1; S7. The first external threaded joint 71 and the second external threaded joint 81 on the two inner pipe sections 11 to be spliced ​​are threadedly connected together using the same double-ended internal threaded joint 5, thereby splicing the two inner pipe sections 11 together; S8. The inner tube electric heating tape 10 of two adjacent segments 1 extending out of their respective polyurethane shells 4 ends is electrically connected together by using a first junction box 30; the outer tube electric heating tape 20 of two adjacent segments 1 extending out of their respective polyurethane shells 4 ends is electrically connected by using a second junction box 40; S9. Polar on-site splicing: Fill the polyurethane foam 3 into the stainless steel casing 2 mounted on the segment 1, move the stainless steel casing 2 together with the polyurethane foam 3 to the transition splicing section, and then apply epoxy glue to the gap between the stainless steel casing 2 and the outer pipe section 12, so that the two ends of the stainless steel casing 2 are respectively bonded to the outside of the two ends of the outer pipe section 12, thereby sealing the transition splicing section.

[0028] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A polar double-layer insulated domestic water delivery pipeline, comprising a plurality of segments (1), each of the segments (1) comprising an inner pipe segment (11) and an outer pipe segment (12), the inner pipe segment (11) and the outer pipe segment (12) being arranged concentrically, the inner pipe segment (11) being arranged inside the outer pipe segment (12), characterized in that: It also includes a stainless steel casing (2), polyurethane foam (3), a polyurethane tube shell (4), and a double-headed internal thread connector (5). The inner tube section (11) comprises a main action section (112) and external threaded joints (111) respectively located on both sides of the main action section (112), and the length of the main action section (112) is consistent with the length of the outer tube section (12), and the two external threaded joints (111) respectively extend out of the two ends of the outer tube section (12), and the adjacent spliced ​​sections (1) are referred to as the first section (7) and the second section (8), the first section (7) comprises a first external threaded joint (71) and a first outer tube section (72), and the second section (8) comprises a second external threaded joint (81) and a second outer tube section (82), and the first external threaded joint (71) and the second external threaded joint (81) which are close to each other are connected together by the same double-headed internal thread joint (5) to form a transition splicing section; The ends of the first outer tube section (72) and the second outer tube section (82) adjacent to each other are respectively referred to as the first end (72a) and the second end (82a), and the two ends of the stainless steel sleeve (2) are respectively sleeved and fixed outside the first end (72a) and the second end (82a); The polyurethane tube shell (4) is sleeved and fixed on the outside of the inner tube section (11), and the outer tube section (12) is sleeved and fixed on the outside of the polyurethane tube shell (4); An annular cavity (9) is provided between the stainless steel sleeve (2) and the transition joint section, and the annular cavity (9) is filled with polyurethane foam (3).

2. The polar double-layer insulated domestic water delivery pipeline according to claim 1, characterized in that: It also comprises an inner tube electric heating tape (10) and an outer tube electric heating tape (20), wherein the inner tube electric heating tape (10) is laid between the inner tube section (11) and the polyurethane tube shell (4), and the outer tube electric heating tape (20) is laid between the polyurethane tube shell (4) and the outer tube section (12).

3. The polar double-layer insulated domestic water delivery pipeline according to claim 2, characterized in that: The inner wall surface of the polyurethane tube shell (4) is provided with an inner groove (41) capable of accommodating the inner tube electric heating belt (10), and the outer wall surface of the polyurethane tube shell (4) is provided with an outer groove (42) capable of accommodating the outer tube electric heating belt (20).

4. The polar double-layer insulated domestic water delivery pipeline according to claim 3 is characterized in that: The inner tube electric heating tape (10) is provided with three, one of which is connected to a power source, and the inner grooves (41) are also provided with three, each of which accommodates one inner tube electric heating tape (10); the outer tube electric heating tape (20) is provided with three, one of which is connected to a power source, and the outer grooves (42) are also provided with three, each of which accommodates one outer tube electric heating tape (20).

5. The polar double-layer insulated domestic water delivery pipeline according to claim 2, characterized in that: The inner tube electric heating cables (10) on two adjacent segments (1) are electrically connected together via a first junction box (30), and the outer tube electric heating cables (20) on two adjacent segments (1) are electrically connected together via a second junction box (40).

6. The assembly process of a polar double-layer insulated domestic water delivery pipeline according to any one of claims 1 to 5, characterized in that: The steps include: S1. Assemble two external threaded joints (111) on both sides of the main action section (112) on a dedicated assembly platform, and weld them using an automatic argon arc welding machine according to the corresponding welding process regulations; S2. Tightness and pressure test of the inner pipe section (11): Use the double-ended internal thread connector (5) and the nut plug fixture to connect the inner pipe section (11) to be tested, and connect the pressure gauge, stop valve, hose and pressure test pump in sequence; The conditions and procedures for the pressure test of the inner pipe section (11) are as follows: a. The inner pipe section (11) is welded according to the design requirements and the welds are qualified after on-site inspection; b. The test medium that meets the requirements has been prepared; the hydraulic medium is clean fresh water, and the chloride ion content in the water does not exceed 30ppm; c. The pressure gauge used in the test has been calibrated and qualified, the accuracy of the pressure gauge is not less than Class 1.5, the full scale value of the gauge is 1.5 to 2 times the maximum measured pressure, and there are no less than two pressure gauges; d. Use compressed air to remove dust and debris in the pipe before testing; use a cloth to clean it if necessary; e. When the ambient temperature of the test site is below 5°C, anti-freezing measures must be taken; f. If there is no abnormality in the water injection inspection, the pressure can be increased. The pressure increase process should be slow and steady. First, the pressure is increased to 0.5MPa, and a comprehensive inspection of the pipeline system is carried out. If there is a problem, the pressure should be released and repaired. It is strictly forbidden to repair under pressure. If there is no abnormality, continue to increase the pressure, first increase it to 25%, 50%, and 75% of the test pressure in sequence, and maintain the pressure for 10 minutes in each step, and finally increase it to the test pressure; g. After the pressure test is qualified, the test medium should be discharged at a suitable location outdoors and pay attention to safety; h. After the pressure test is completed, all temporary devices should be removed in time, the records should be checked, and the "Water Pressure Test Record" should be filled in; S3. Lay the inner pipe electric heating cable (10) outside the inner pipe section (11) according to the drawing requirements, and then lay the polyurethane shell (4) on the outside. The inner pipe electric heating cable (10) needs to extend out of a portion of the end of the polyurethane shell (4) so ​​as to be spliced ​​with the inner pipe electric heating cable (10) of other sections (1) on site; S4. An outer groove (42) is formed on the outer wall of the polyurethane shell (4), and then an outer tube electric heating cable (20) is laid on the outer wall of the polyurethane shell (4). The outer tube electric heating cable (20) needs to extend out of a portion of the end of the polyurethane shell (4) so ​​as to be spliced ​​with the outer tube electric heating cable (20) of other segments (1) on site; S5. Use a special pipe threading device to insert the outer pipe section (12) onto the outside of the polyurethane pipe shell (4) and the outer pipe electric heating cable (20). Be careful not to damage the polyurethane pipe shell (4) and the outer pipe electric heating cable (20) during the pipe threading. S6. Pre-install the stainless steel casing (2) on the segment (1); S7. Using the same double-ended internal thread connector (5), the first external thread connector (71) and the second external thread connector (81) on the two inner pipe sections (11) to be spliced ​​are threadedly connected together, thereby splicing the two inner pipe sections (11); S8. Using a first junction box (30), the inner tube electric heating cables (10) of two adjacent segments (1) extending out of the ends of their respective polyurethane tube shells (4) are electrically connected together; using a second junction box (40), the outer tube electric heating cables (20) of two adjacent segments (1) extending out of the ends of their respective polyurethane tube shells (4) are electrically connected; S9. Polar on-site splicing: Fill the polyurethane foam (3) into the stainless steel sleeve (2) mounted on the segment (1), move the stainless steel sleeve (2) together with the polyurethane foam (3) to the transition splicing section, and then apply epoxy glue to the gap between the stainless steel sleeve (2) and the outer pipe section (12), so that the two ends of the stainless steel sleeve (2) are respectively bonded to the outside of the two ends of the outer pipe section (12), thereby sealing the transition splicing section.

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