Anti-corrosion environment-friendly foamed plastic heat preservation pipe

Abstract

The invention relates to the technical field of liquefied natural gas transportation, in particular to an anti-corrosion environment-friendly foamed plastic heat preservation pipe which comprises an inner pipe, polyurethane foam and a polyethylene outer pipe which are sequentially connected and further comprises a sleeve, a first annular plate, a protection assembly, an installation pipe and a rotational flow assembly. The protection assembly is arranged on the first annular plate, and after the two inner pipes are welded, the protection assembly isolates the liquefied natural gas from making contact with the welding position of the two inner pipes through the adjacent sleeves. Through the corrugated pipe, the first sleeve and the sealing ring, direct contact between the welding position and liquefied natural gas can be isolated, rotational flow can be formed in the liquefied natural gas conveying process under the action of the impeller and the spiral blade, impact of turbulent flow in a pipeline is reduced, and the conveying efficiency is improved. The situation that microcracks appear on the inner wall of the pipeline and the welding position is effectively avoided, and therefore the inner wall of the pipeline and the welding position can be prevented from being corroded.

Description

Technical Field

[0001] The invention relates to the technical field of liquefied natural gas transportation, in particular to an anti-corrosion and environment-friendly foam plastic insulation pipe. Background Art

[0002] Liquefied natural gas is a liquid that is compressed and cooled to its freezing point. Its main component is methane, which needs to be re-gasified when used. Natural gas resources in some northern regions are relatively scarce and cannot meet local usage needs. Therefore, it is necessary to transport liquefied natural gas through pipeline installation. Among them, polyurethane foam installation pipe is an effective anti-corrosion and environmentally friendly foam plastic installation pipe. When liquefied natural gas is transported in pipelines, there is a possibility of corrosive gases mixing in, which will cause corrosion to the inner wall of the pipeline during transportation. Especially when the transportation speed is not considered, the contact time between liquefied natural gas and the inner wall of the pipeline is longer, which will aggravate the degree of corrosion.

[0003] In view of the above problems, there are good solutions in the prior art. Through high-precision polishing of stainless steel pipes and the inner wall of stainless steel pipes, the inner wall of the polished stainless steel pipe is conducive to forming a dense and stable passivation film to prevent the surface of the pipe from contacting corrosive substances, thereby effectively preventing corrosion. However, the following problems still exist: Since the temperature of liquefied natural gas is usually stable at around minus 162 degrees Celsius, the pipeline is in an ultra-low temperature environment for a long time, and microcracks are generated along with the turbulence effect during the transportation of liquefied natural gas. When liquefied natural gas is transported over long distances, the welding positions of two adjacent pipelines will produce large residual stresses after welding. In an ultra-low temperature environment, the stress will be amplified, making it easier to generate microcracks at the weld. After the microcracks are generated, the passivation film on the inner wall of the pipeline will be destroyed, which will still cause corrosion of the inner wall of the pipeline.

[0004] Therefore, in order to solve the above problems, an anti-corrosion and environmentally friendly foam plastic insulation pipe is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide an anti-corrosion and environmentally friendly foam plastic insulation pipe, which solves the problem that microcracks are easily formed on the inner wall and welding position of the pipeline in an ultra-low temperature environment, thereby causing corrosion of the inner wall of the pipeline during the transportation of liquefied natural gas. The bellows, sleeve 1 and sealing ring can be arranged to isolate the direct contact between the welding position and the liquefied natural gas, and a swirl can be formed during the transportation of the liquefied natural gas under the action of the impeller and the spiral blade, reducing the impact of turbulence inside the pipeline, effectively avoiding the occurrence of microcracks on the inner wall and welding position of the pipeline, thereby avoiding corrosion of the inner wall and welding position of the pipeline.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A corrosion-resistant and environmentally friendly foam plastic insulation pipe comprises an inner pipe, a polyurethane foam and a polyethylene outer pipe connected in sequence, and also comprises a sleeve, an annular plate, a protective component, a mounting pipe and a swirl component. The sleeve and the annular plate are respectively passed through the left and right ends of the inner pipe, and the protective component is arranged on the annular plate. After the two inner pipes are welded, the protective component isolates the contact between the liquefied natural gas and the welding positions of the two inner pipes through the adjacent sleeves. The mounting pipe is arranged inside the annular plate. The swirl component is arranged inside the sleeve and the annular plate. When the liquefied natural gas flows through the welding positions of the two inner pipes, the swirl component gathers the liquefied natural gas through the mounting pipe and forms a swirl.

[0008] It can be seen that in an ultra-low temperature environment, microcracks are easily generated on the surface of the inner tube, especially at the welding position. Due to the residual stress generated during welding, the welding position is more likely to generate microcracks under ultra-low temperature conditions. After the microcracks are generated on the surface of the inner tube, the passivation film on the surface of the inner tube will be destroyed, and the contact area between the corrosive gas mixed in the liquefied natural gas and the inner wall of the inner tube will increase, thereby causing the inner wall of the inner tube to corrode under the action of the corrosive gas, thereby affecting the service life of the inner tube. Therefore, this solution is adopted. After the two inner tubes are welded, the contact between the welding position and the liquefied natural gas can be isolated, avoiding the situation where microcracks are generated at the welding position in an ultra-low temperature environment. At the same time, a vortex can be formed during the transportation of liquefied natural gas, reducing the generation of turbulence in the inner tube, thereby effectively avoiding the generation of microcracks inside the inner tube and at non-welding positions, and achieving effective corrosion protection for the surface of the inner tube and the welding position.

[0009] Preferably, the protective assembly includes a sleeve 1, a bellows, a sealing ring and an elastic telescopic rod. The sleeve 1 is arranged on the right side of the annular plate 1 and is arranged to pass through the inside. The bellows is arranged between the annular plate 1 and the sleeve 1 and is socketed with the mounting tube. The sealing ring is arranged on the right side of the sleeve 1. The elastic telescopic rod is arranged outside the bellows and a plurality of them are arranged in a circular array. The two ends of the elastic telescopic rod are respectively connected to the annular plate 1 and the sleeve 1. When the two inner tubes are welded, the right end of the fixed section of the elastic telescopic rod contacts the sleeve 1.

[0010] It can be seen that the welding position of the two inner tubes is more prone to microcracks in ultra-low temperature environments than other positions of the inner tubes due to the presence of residual stress. Therefore, by adopting this solution, after the two inner tubes are butt-jointed, the liquefied natural gas can be isolated from the welding position of the two inner tubes by using the bellows and the sleeve to avoid direct contact between the liquefied natural gas and the welding position of the two inner tubes, thereby avoiding the occurrence of microcracks in the welding position in an ultra-low temperature environment and achieving effective corrosion protection of the welding position.

[0011] Preferably, the swirl assembly includes a second sleeve, a fixed rod, an impeller, a rotating rod, a spiral blade, an insertion rod and a mounting assembly, the second sleeve is arranged inside the sleeve and connected to the inner wall of the sleeve through the fixed rod, the impeller is rotatably sleeved with the second sleeve and a slot is opened at the end, the rotating rod is arranged inside the mounting tube, the spiral blade is arranged on the rod wall of the rotating rod, the spiral direction of the spiral blade is counterclockwise along the conveying direction of the liquefied natural gas, the insertion rod is arranged at the end of the rotating rod and matches the slot, the mounting assembly is arranged on the rotating rod, and the rotating rod is connected to the mounting tube through the mounting assembly, and the mounting assembly fixes the radial position of the rotating rod and further guides the liquefied natural gas to form a swirl when the liquefied natural gas is conveyed.

[0012] It can be seen that even if the transportation speed of liquefied natural gas inside the inner tube is not considered, turbulence will be generated during the transportation process. In the ultra-low temperature environment, turbulence will accelerate the formation of microcracks on the inner wall of the inner tube, thereby causing corrosion inside the inner tube when transporting liquefied natural gas. Therefore, this solution is adopted. Under the dual action of the impeller and the spiral blades, when liquefied natural gas flows through the inside of the installation pipe, the kinetic energy of the liquefied natural gas and the northern earth's magnetic field can drive the impeller and the spiral blades to rotate, so that after the liquefied natural gas flows out from the inside of the installation pipe, a swirl effect can be formed, avoiding the formation of microcracks on the inner wall of the inner tube in the ultra-low temperature environment, thereby achieving effective corrosion protection of the inner wall of the inner tube and non-welding positions.

[0013] Preferably, the mounting assembly includes an annular plate 2 and a mounting plate, the annular plate 2 is provided with two and is symmetrically rotatably sleeved on both ends of the rotating rod, the mounting plate is provided with multiple and is arranged in a circular array between the annular plate 2 and the mounting tube, the mounting plate is arranged with a tendency to expand outward along the conveying direction of the liquefied natural gas, and a guide groove is provided on the side of the mounting plate opposite to the conveying direction of the liquefied natural gas.

[0014] By adopting the above scheme, the axial position of the rotating rod can be fixed while ensuring the coaxial arrangement of the rotating rod and the inner tube, and the flow direction of the liquefied natural gas flowing through can be further guided, so that the liquefied natural gas can enter the guide groove after flowing through the interior of the mounting plate. After entering the interior of the guide groove, the liquefied natural gas can be guided by the guide groove to expand in a swirling flow in a direction away from the axis of the inner tube, thereby reducing the interference of the mounting plate on the swirling flow effect during the flow of the liquefied natural gas, stabilizing the swirling flow effect and reducing the generation of turbulence, avoiding the occurrence of microcracks on the inner wall of the inner tube and at non-welding positions in an ultra-low temperature environment, and achieving effective corrosion protection of the inner wall of the inner tube.

[0015] Preferably, the side wall of the second sleeve is provided with an arc-shaped hole, a plurality of the arc-shaped hole arrays are provided, and the arc-shaped holes are arranged in a clockwise trend along the conveying direction of the liquefied natural gas.

[0016] By adopting the above scheme, after the liquefied natural gas enters the interior of the second sleeve, it can rotate and flow out in the axial direction of the second sleeve under the action of the arc hole, thereby forming a preliminary vortex, reducing the kinetic energy loss caused by obstruction during the transportation of the liquefied natural gas. In addition, in the northern region, the direction of the earth's magnetic field will cooperate with the rotation direction of the arc hole, promoting the clockwise rotation of the liquefied natural gas flowing out of the arc hole, thereby enhancing the vortex effect during the transportation of the liquefied natural gas.

[0017] Preferably, a driving groove is provided on the side of the spiral blade opposite to the liquefied natural gas conveying direction, and the diameter of the driving groove is arranged to increase from the surface of the spiral blade to the inside of the spiral blade.

[0018] By adopting the above scheme, the liquefied natural gas can flow stably inside the driving groove after entering the driving groove, so that the kinetic energy during the liquefied natural gas transportation process can further drive the spiral blade to rotate, thereby increasing the swirl effect during the flow of the liquefied natural gas and reducing the generation of turbulence, avoiding the irregular movement of the turbulent flow from hitting the inner wall of the inner tube and aggravating the generation of microcracks on the inner wall of the inner tube in an ultra-low temperature environment, thereby achieving effective corrosion protection of the inner wall of the inner tube and non-welding positions.

[0019] Preferably, the internal space of the sleeve is arranged in a truncated cone shape, and the diameter of the left end of the sleeve is smaller than the diameter of the right end.

[0020] By adopting the above scheme, the liquefied natural gas will gradually gather after entering the interior of the sleeve one, avoiding the right end of the sleeve one from blocking the transportation of the liquefied natural gas, and at the same time, the gathered liquefied natural gas can be concentrated to impact the impeller, so that a vortex can be formed through the action of the impeller in the process of flowing from the interior of the sleeve one to the interior of the next inner tube, effectively avoiding the formation of turbulence, that is, effectively avoiding the situation where microcracks are generated in the non-welded position inside the inner tube due to the influence of ultra-low temperature, thereby achieving further corrosion protection of the inner tube.

[0021] Preferably, the guide groove is arranged obliquely, the diameter of the guide groove decreases from the axial position of the inner tube to the edge, and the depth of the guide groove increases from the axial position of the inner tube to the edge.

[0022] By adopting the above scheme, the size of the slot and the depth change of the guide slot can be utilized to realize accelerated guidance of the liquefied natural gas that hits the mounting plate, thereby increasing the swirl speed of the liquefied natural gas when it flows out from the inside of the mounting pipe, further reducing the turbulent effect of the liquefied natural gas when it is transported inside the inner pipe, and thus effectively avoiding microcracks on the inner wall of the inner pipe caused by turbulence in an ultra-low temperature environment, further realizing the anti-corrosion effect on the inner wall of the inner pipe.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. By providing the bellows and the elastic telescopic rod, after the two inner tubes are welded, the bellows, the sleeve 1 and the sealing ring can be used to isolate the liquefied natural gas from the welding position under the close fit of the sealing ring and the sleeve, thereby preventing the residual stress generated during welding from causing micro cracks at the welding position under the influence of the ultra-low temperature environment, thereby achieving an anti-corrosion effect on the welding position. Moreover, after welding, the bellows cannot shrink due to the length limit of the fixed section of the elastic telescopic rod, thereby preventing the sleeve 1 arranged at the right end of the bellows from separating from the sleeve due to the pressure of the liquefied natural gas during transportation, that is, preventing the liquefied natural gas from leaking to the outside of the bellows during transportation, thereby further achieving effective anti-corrosion of the welding position.

[0025] 2. By setting the impeller, rotating rod, spiral blade, plug rod and slot, the two inner tubes can be pre-positioned by plugging the plug rod into the corresponding slot before welding, ensuring that the two inner tubes can be coaxially arranged before welding, and after welding, the impeller and the rotating rod can be synchronously rotated under the plugging action of the plug rod and the slot, so that the magnetic field of the northern earth can be coordinated during the flow of liquefied natural gas, the turbulence generated during the transportation of liquefied natural gas can be reduced, and the swirl effect can be increased, so that the liquefied natural gas flows in a rotating state around the axis of the inner tube, which is usually a more orderly flow form. Swirling flow may cause local high-pressure areas or areas with strong centrifugal force, but it is generally less destructive to the inner wall of the pipeline. The shear force of the swirl is usually more stable and does not change drastically like turbulence, so the direct damage to the inner wall is lighter, which can effectively avoid the situation where microcracks are generated on the inner wall of the inner tube and the non-welding position in an ultra-low temperature environment, and thus can achieve effective corrosion protection of the inner wall of the inner tube.

[0026] 3. By setting the installation pipe and the internal space setting of the casing, a double gathering effect can be achieved for the transported liquefied natural gas, so that the liquefied natural gas can effectively hit the impeller and the spiral blades during the transportation process, avoiding the diffusion of the liquefied natural gas before flowing out from the inside of the installation pipe, so that the liquefied natural gas can be stably transported in a swirl state, further enhancing the swirl effect during the transportation of the liquefied natural gas, that is, further avoiding the situation where microcracks are generated in the inner tube under ultra-low temperature environment, and effectively ensuring the anti-corrosion effect of the inner tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention;

[0028] Figure 2 This is a state diagram of two inner tubes after welding of the present invention;

[0029] Figure 3 It is a schematic diagram of a partial cross-sectional connection structure of the sleeve, the annular plate, the protection assembly and the mounting pipe of the present invention;

[0030] Figure 4 It is a schematic diagram of a partial cross-sectional connection structure of the sleeve, the mounting tube and the swirl assembly of the present invention;

[0031] Figure 5 For the present invention Figure 4 Enlarged view of the middle part A;

[0032] Figure 6 It is a schematic diagram of the connection structure of the sleeve and the mounting pipe, the swirl assembly and the mounting assembly of the present invention;

[0033] Figure 7 It is a schematic diagram of the connection structure of the swirl component and the mounting component of the present invention;

[0034] Figure 8 For the present invention Figure 7 Enlarged view of part B in the middle.

[0035] In the figure: 1, inner tube; 2, polyurethane foam; 3, polyethylene outer tube; 4, sleeve; 5, annular plate 1; 6, protective assembly; 61, sleeve 1; 62, bellows; 63, sealing ring; 64, elastic telescopic rod; 7, mounting tube; 8, swirl assembly; 81, sleeve 2; 811, arc hole; 82, fixing rod; 821, slot; 83, impeller; 84, rotating rod; 85, spiral blade; 851, driving groove; 86, plug rod; 87, mounting assembly; 871, annular plate 2; 872, mounting plate; 873, guide groove. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0037] See also Figures 1 to 8 The present invention provides an anti-corrosion and environmentally friendly foam plastic insulation pipe, and the technical solution is as follows:

[0038] For details, please refer to Figure 1 , Figure 2 and Figure 3, an anti-corrosion and environmentally friendly foam plastic insulation pipe, comprising an inner pipe 1, a polyurethane foam 2 and a polyethylene outer pipe 3 connected in sequence, the inner pipe 1 is made of stainless steel and the inner wall is polished so that the inner wall of the inner pipe 1 forms a dense and stable passivation film, and the polyurethane foam 2 is used to achieve insulation, so as to prevent the liquefied natural gas from being disturbed by the temperature difference between the inside and the outside during the transportation process, and also includes a sleeve 4, an annular plate 5, a protective component 6, a mounting pipe 7 and a swirl component 8, the sleeve 4 and the annular plate 5 are respectively arranged at the left and right ends of the inner pipe 1, and the sleeve 4 and the annular plate 5 can be fixed to the inside of the inner pipe 1 by welding after an annular groove is opened, the sleeve 4 and the annular plate 5 are respectively arranged at the left and right ends of the inner pipe 1, and the opposite sides of the sleeve 4 and the annular plate 5 can be fixed to the inside of the inner pipe 1 by welding after annular grooves are opened, the The protection component 6 is arranged on the annular plate 5, and the protection component 6 includes a sleeve 61, a bellows 62, a sealing ring 63 and an elastic telescopic rod 64. The sleeve 61 is arranged on the right side of the annular plate 5 and is arranged to pass through the inside. The bellows 62 is arranged between the annular plate 5 and the sleeve 61, and is sleeved with the mounting tube 7. The sealing ring 63 is arranged on the right side of the sleeve 61. The elastic telescopic rod 64 is arranged outside the bellows 62 and a plurality of them are arranged in a circular array. The two ends of the elastic telescopic rod 64 are respectively connected to the annular plate 5 and the sleeve 61. When the two inner tubes 1 are welded, the right end of the fixed section of the elastic telescopic rod 64 contacts the sleeve 61.

[0039] Under the above-mentioned setting conditions, after the two inner tubes 1 are welded, the elastic force of the elastic telescopic rod 64 will squeeze the sleeve 61, so that the sealing ring 63 installed on the side wall of the sleeve 61 is kept in close contact with the side wall of the sleeve 4, and the right end of the fixed section of the elastic telescopic rod 64 is always kept in close contact with the left side of the sleeve 61 after welding. Since the transformation of natural gas from gas to liquid requires high pressure conditions, the sealing effect between the sealing ring 63 and the sleeve 4 can be guaranteed during the transportation of liquefied natural gas, and there will be no gap between the sealing ring 63 and the sleeve 4 due to pressure, so that under the isolation of the bellows 62, the liquefied natural gas can be prevented from contacting the welding point, which not only avoids the occurrence of microcracks in the welding point due to the residual stress generated during welding in an ultra-low temperature environment, but also effectively avoids the occurrence of corrosion in the welding point.

[0040] As an embodiment of the present invention, refer to Figure 4 , Figure 5 and Figure 8The mounting tube 7 is arranged inside the annular plate 1 5, the swirl assembly 8 is arranged inside the sleeve 4 and the annular plate 1 5, the swirl assembly 8 includes a sleeve 2 81, a fixing rod 82, an impeller 83, a rotating rod 84, a spiral blade 85, an insert rod 86 and a mounting assembly 87, the sleeve 2 81 is arranged inside the sleeve 4, and is connected to the inner wall of the sleeve 4 through the fixing rod 82, the impeller 83 is rotatably sleeved with the sleeve 2 81 and a slot 821 is opened at the end, and the rotating rod 84 is arranged inside the mounting tube 7, The spiral blade 85 is arranged on the rod wall of the rotating rod 84, and the spiral direction of the spiral blade 85 is arranged counterclockwise along the conveying direction of the liquefied natural gas. The insertion rod 86 is arranged at the end of the rotating rod 84 and matches with the slot 821. The internal space of the sleeve 4 is arranged in a truncated cone shape, and the left end diameter of the sleeve 4 is smaller than the right end diameter. The side wall of the sleeve 81 is provided with an arc hole 811, and the arc hole 811 array is provided with a plurality of arc holes 811, and the arc holes 811 are arranged in a clockwise trend along the conveying direction of the liquefied natural gas.

[0041] Under the action of the installation pipe 7, the liquefied natural gas delivered to the welding position of the two inner pipes 1 can be gathered, so that the liquefied natural gas can drive the impeller 83 to rotate when it hits the impeller 83 during the flow process, and after entering the interior of the sleeve 81, it can flow out from the arc hole 811 opened on the side wall of the sleeve 81. In the process of outflow, in conjunction with the northern earth magnetic field (the direction of the magnetic field in the northern hemisphere is clockwise) and the rotation of the impeller 83, the turbulence generated by the flow of the liquefied natural gas is transformed into a vortex. By using the insertion rod 86 and the slot 821 opened at the end of the impeller 83, the two inner pipes 1 can be welded together. Before, the coaxial positioning of the two inner tubes 1 is achieved by plugging the insertion rod 86 and the corresponding slot 821, which effectively simplifies the positioning process of the two inner tubes 1 before welding, and the rotating rod 84 can be driven to drive the spiral blades 85 to rotate synchronously during the rotation of the impeller 83, and then the swirl effect is further enhanced under the action of the rotating rod 84 and the spiral blades 85, reducing the turbulence of the liquefied natural gas after it flows out from the inside of the installation pipe 7, thereby reducing the impact of the liquefied natural gas on the inner wall of the inner tube 1 during the transportation of the liquefied natural gas, avoiding the occurrence of microcracks at the non-welding position of the inner wall of the inner tube 1 in the ultra-low temperature environment, thereby achieving the anti-corrosion effect on the inner wall of the inner tube 1.

[0042] As an embodiment of the present invention, refer to Figure 6The mounting assembly 87 is arranged on the rotating rod 84, and the rotating rod 84 is connected to the mounting tube 7 through the mounting assembly 87. The mounting assembly 87 includes an annular plate 871 and a mounting plate 872. The annular plate 871 is provided with two and is symmetrically rotatably sleeved on both ends of the rotating rod 84. The mounting plate 872 is provided with multiple and a circular array is arranged between the annular plate 871 and the mounting tube 7. The mounting plate 872 is arranged with a tendency to expand outward along the conveying direction of liquefied natural gas. A guide groove 873 is provided on the side of the mounting plate 872 opposite to the conveying direction of liquefied natural gas. The guide groove 873 is inclined, and the diameter of the guide groove 873 decreases from the axial position of the inner tube 1 to the edge, and the depth of the guide groove 873 increases from the axial position of the inner tube 1 to the edge.

[0043] Under the above-mentioned setting conditions, the coaxial installation of the rotating rod 84 and the inner tube 1 can be achieved, and after installation, the turbulence effect on the liquefied natural gas can be effectively reduced. When the liquefied natural gas impacts the inside of the guide groove 873 opened on the surface of the mounting plate 872, it can flow to the edge of the inner tube 1 under the guidance of the guide groove 873, thereby reducing the influence of the turbulence generated during the transportation of the liquefied natural gas on the swirl effect, thereby achieving further protection of the inner wall of the inner tube 1, that is, further avoiding the situation where the inner wall of the inner tube 1 is subjected to irregular impact of turbulence in an ultra-low temperature environment. The inner wall of the inner tube 1 is prevented from generating microcracks, and the anti-corrosion effect on the inner wall of the inner tube 1 is further improved.

[0044] As an embodiment of the present invention, refer to Figure 6 and Figure 7 A driving groove 851 is formed on the side of the spiral blade 85 opposite to the liquefied natural gas conveying direction, and the diameter of the driving groove 851 is gradually increased from the surface of the spiral blade 85 to the inside of the spiral blade 85 .

[0045] Under the above-mentioned setting conditions, since the bottom width of the driving groove 851 is greater than the slot opening width, the flow direction of the liquefied natural gas can be restricted after entering the driving groove 851, reducing the flow from the bottom position of the driving groove 851 to the slot opening position, so that the liquefied natural gas is forced to be transported in a spiral manner, and the driving groove 851 is the same as the spiral manner of the spiral blade 85. The bottom of the driving groove 851 will be squeezed during the flow of the liquefied natural gas. The squeezing of the surface of the spiral blade 85 by the liquefied natural gas can accelerate the rotation of the spiral blade 85, thereby further increasing the swirl effect of the liquefied natural gas and further reducing the turbulence generated during the transportation of the liquefied natural gas, that is, avoiding the situation where the inner wall of the inner tube 1 is subjected to microcracks due to ultra-low temperature during the transportation of the liquefied natural gas, and further improving the anti-corrosion effect of the inner wall of the inner tube 1 and the non-welding position.

[0046] Working principle: In order to achieve corrosion protection of the welding position of the two inner tubes 1, refer to Figure 2 and Figure 3 After the two inner tubes 1 are welded, the sleeve 61, the bellows 62, the sealing ring 63 and the elastic telescopic rod 64 are arranged inside the two inner tubes 1 to isolate the welding position from the outside of the bellows 62, thereby isolating the contact between the liquefied natural gas and the welding position, avoiding the situation where micro cracks are generated at the welding position under ultra-low temperature environment, thereby achieving effective corrosion protection of the welding position; in order to achieve corrosion protection of the inner wall of the inner tube 1 and the non-welding position, refer to Figure 3 , Figure 4 and Figure 6 By using the impeller 83 and the spiral blades 85, a swirl can be formed during the liquefied natural gas transportation process to reduce the turbulence effect, thereby avoiding the irregular flow of the liquefied natural gas caused by the turbulence and the collision with the inner wall of the inner tube 1, thereby effectively avoiding the occurrence of micro cracks on the inner wall of the inner tube 1 in an ultra-low temperature environment, and further achieving effective corrosion protection of the inner wall of the inner tube 1 and non-welding positions.

[0047] Specific:

[0048] Reference Figure 2 , Figure 3 , Figure 4 and Figure 5 Before welding the two inner tubes 1, the insertion rod 86 is plugged into the corresponding slot 821 on the impeller 83, so as to realize the coaxial positioning of the two inner tubes 1, adjust the positions of the two inner tubes 1, and make the two inner tubes 1 close to each other. In the process of the two inner tubes 1 approaching each other, the sleeve 61 will contact the sleeve 4 and make the elastic telescopic rod 64 contract. After the elastic telescopic rod 64 contracts to the maximum extent, the movement of the sleeve 61 will be restricted. At this time, under the action of the sealing ring 63, the liquefied natural gas can be prevented from flowing to the outside of the bellows 62 during the transportation process, so as to realize the isolation of the liquefied natural gas and the welding position of the two inner tubes 1, and avoid the occurrence of micro cracks at the welding position in the ultra-low temperature environment, so as to realize the effective corrosion protection of the welding position.

[0049] Reference Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6, it can be seen that the radial cross-sections of the plug rod 86 and the slot 821 are both rectangular. After the plug rod 86 is connected to the slot 821, the impeller 83 and the rotating rod 84 can rotate synchronously. After the liquefied natural gas enters the interior of the casing 4 during transportation, it can form a gathering effect through the space inside the casing 4, and after gathering, it can impact the impeller 83 and the spiral blade 85, so that the impeller 83 and the spiral blade 85 are under the action of the impact force, and cooperate with the effect of the northern earth magnetic field, so that the impeller 83 and the spiral blade 85 rotate clockwise along the transportation direction of the liquefied natural gas, so that the liquefied natural gas can form a swirl during transportation and reduce the turbulence effect, that is, reduce the irregular collision effect of the liquefied natural gas with the inner wall of the inner tube 1 due to the large turbulence after flowing out from the inside of the installation tube 7, effectively avoid the situation where the inner wall of the inner tube 1 is micro-cracked in an ultra-low temperature environment, and achieve effective corrosion protection of the inner wall of the inner tube 1 and the non-welding position;

[0050] Reference Figure 2 , Figure 6 , Figure 7 and Figure 8 In the process of entering the arc hole 811 and the driving groove 851 and flowing out from the arc hole 811 and the driving groove 851, the liquefied natural gas can move in the direction deviating from the axis of the installation pipe 7, so that in the process of liquefied natural gas transportation, the swirl effect inside the inner tube 1 can be further increased, that is, the impact on the inner tube 1 due to the irregular flow of turbulence is reduced, and the microcracks on the inner wall of the inner tube 1 in an ultra-low temperature environment are further avoided, that is, the effective corrosion protection of the inner wall of the inner tube 1 and the non-welding position is further achieved.

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An anti-corrosion and environmentally friendly foam plastic insulation pipe, comprising an inner pipe (1), polyurethane foam (2) and a polyethylene outer pipe (3) connected in sequence, characterized in that: The invention also comprises a sleeve (4), an annular plate (5), a protection component (6), a mounting pipe (7) and a swirl component (8); the sleeve (4) and the annular plate (5) are respectively arranged at the left and right ends of the inner tube (1); the protection component (6) is arranged on the annular plate (5); after the two inner tubes (1) are welded, the protection component (6) isolates the liquefied natural gas from contacting the welding position of the two inner tubes (1) through the adjacent sleeve (4); the mounting pipe (7) is arranged inside the annular plate (5); the swirl component (8) is arranged inside the sleeve (4) and the annular plate (5); when the liquefied natural gas flows through the welding position of the two inner tubes (1), the swirl component (8) gathers the liquefied natural gas through the mounting pipe (7) and forms a swirl.

2. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 1, characterized in that: The protective component (6) comprises a sleeve (61), a bellows (62), a sealing ring (63) and an elastic telescopic rod (64); the sleeve (61) is arranged on the right side of the annular plate (5) and is arranged to pass through the inside; the bellows (62) is arranged between the annular plate (5) and the sleeve (61) and is sleeved with the mounting tube (7); the sealing ring (63) is arranged on the right side of the sleeve (61); the elastic telescopic rod (64) is arranged outside the bellows (62) and a plurality of the elastic telescopic rods (64) are arranged in a circular array; the two ends of the elastic telescopic rod (64) are respectively connected to the annular plate (5) and the sleeve (61); when the two inner tubes (1) are welded, the right end of the fixed section of the elastic telescopic rod (64) contacts the sleeve (61).

3. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 1, characterized in that: The swirl assembly (8) comprises a second sleeve (81), a fixing rod (82), an impeller (83), a rotating rod (84), a spiral blade (85), an insert rod (86) and a mounting assembly (87); the second sleeve (81) is arranged inside the sleeve (4) and connected to the inner wall of the sleeve (4) through the fixing rod (82); the impeller (83) is rotatably sleeved with the second sleeve (81) and a slot (821) is provided at the end thereof; the rotating rod (84) is arranged inside the mounting tube (7); the spiral blade (85) is arranged The spiral blade (85) is arranged on the rod wall of the rotating rod (84), and the spiral direction of the spiral blade (85) is arranged counterclockwise along the conveying direction of the liquefied natural gas. The plug rod (86) is arranged at the end of the rotating rod (84) and matches with the slot (821). The mounting assembly (87) is arranged on the rotating rod (84), and the rotating rod (84) is connected to the mounting pipe (7) through the mounting assembly (87). When the liquefied natural gas is conveyed, the mounting assembly (87) fixes the radial position of the rotating rod (84) and further guides the liquefied natural gas to form a swirl.

4. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 3, characterized in that: The mounting assembly (87) comprises an annular plate 2 (871) and a mounting plate (872). The annular plate 2 (871) is provided with two and is symmetrically rotatably sleeved on the two ends of the rotating rod (84). The mounting plate (872) is provided with a plurality of and is arranged in a circular array between the annular plate 2 (871) and the mounting pipe (7). The mounting plate (872) is arranged with a tendency to expand outward along the conveying direction of liquefied natural gas. A guide groove (873) is provided on the side of the mounting plate (872) opposite to the conveying direction of liquefied natural gas.

5. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 3, characterized in that: The side wall of the second sleeve (81) is provided with an arc-shaped hole (811), and a plurality of the arc-shaped holes (811) are provided in an array. The arc-shaped holes (811) are arranged in a clockwise direction along the conveying direction of the liquefied natural gas.

6. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 3, characterized in that: A driving groove (851) is provided on the side of the spiral blade (85) opposite to the liquefied natural gas conveying direction, and the diameter of the driving groove (851) is gradually increased from the surface of the spiral blade (85) to the inside of the spiral blade (85).

7. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 2, characterized in that: The internal space of the sleeve (4) is arranged in a truncated cone shape, and the diameter of the left end of the sleeve (4) is smaller than the diameter of the right end.

8. The anti-corrosion and environmentally friendly foam plastic insulation pipe according to claim 4, characterized in that: The guide groove (873) is arranged obliquely, the diameter of the guide groove (873) decreases from the axial position of the inner tube (1) to the edge, and the depth of the guide groove (873) increases from the axial position of the inner tube (1) to the edge.

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