Spraying and winding process for directly-buried thermal insulation pipe

Abstract

The invention relates to a direct burial thermal insulation pipe spraying and winding process applied to the related technical field of thermal insulation pipes, through the arrangement of a shaping ring, in the spraying process along with a spray gun, the convex part of a sprayed polyurethane layer can be corrected and shaped, the local protruding part can be flattened, the concentricity can be improved, meanwhile, the concave part can be detected, and the spraying effect can be improved. In addition, by means of the arrangement of the material guiding pipes, when the polyurethane is subjected to shaping and depression detection and local depression is detected, the two material guiding pipes can be triggered to spray powder, so that the defect position is limited, follow-up fixed-point repair is facilitated, and the production efficiency is improved. And the quality of the directly-buried thermal insulation pipe finished product is further ensured.

Description

Technical Field

[0001] The present invention relates to a direct-buried thermal insulation pipe spraying and winding process, in particular to a direct-buried thermal insulation pipe spraying and winding process applied to the technical field related to thermal insulation pipes. Background Art

[0002] Polyurethane spray-wrapped insulated pipes are highly efficient and energy-saving, reduce heat loss, are environmentally friendly and non-toxic, and are corrosion-resistant and wear-resistant. They are widely used in construction, chemical, petroleum and other fields. They have broad prospects and help energy conservation, environmental protection and green development.

[0003] Chinese patent CN118849489A discloses a spray-wrapped direct-buried insulated pipe production process, which solves the problem of insufficient protection of the pipe mouth. However, when the polyurethane is sprayed, since foaming is required after spraying, the surface is often prone to unevenness, resulting in a low concentricity between the formed polyurethane insulation layer and the internal steel pipe. However, the above problem is difficult to detect in time, affecting the quality of the finished insulated pipe. Summary of the invention

[0004] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that after spraying polyurethane, the polyurethane foaming easily has a problem of low concentricity with the inner steel pipe, which affects the quality of the finished direct-buried thermal insulation pipe.

[0005] In order to solve the above problems, the present invention provides a spray winding process for a directly buried thermal insulation pipe, wherein the directly buried thermal insulation pipe comprises an inner steel pipe, a polyurethane thermal insulation layer and a polyethylene outer sheath from the inside to the outside, and comprises the following steps: S1. First, grind and clean the inner steel pipe to remove rust and oil stains on the surface, then pass the inner steel pipe through the shaping ring and place it on two sets of rotating rollers, so that the two ends of the inner steel pipe are respectively placed on the two sets of rotating rollers, and the inner steel pipe is driven to rotate continuously by the rotating rollers. An electric slide rail is set in the middle above the two sets of rotating rollers, and the shaping ring is connected to the electric slide rail; S2. Spraying polyurethane on the surface of the inner steel pipe by a spray gun, wherein the spray gun is fixedly connected to the shaping ring by a bracket, so that the shaping ring and the spray gun can move synchronously along the electric slide rail, and with the rotation of the inner steel pipe and the linear movement of the spray gun, the polyurethane is evenly sprayed on the surface of the inner steel pipe to form a polyurethane insulation layer. When the spray gun moves, the shaping ring moves on the surface of the polyurethane insulation layer, thereby shaping and adjusting the foaming polyurethane insulation layer and synchronously detecting local depressions; S3. When local depressions are detected in the polyurethane insulation layer, targeted treatment can be carried out to fill the depressions, and then winding treatment can be carried out. When no depressions are detected, winding treatment can be carried out directly after foaming. At this time, the strip polyethylene extruded by the extruder is evenly wound around the outside of the polyurethane insulation layer. After cooling, the polyethylene shrinks and tightly wraps around the outside of the polyurethane insulation layer to complete the spray winding of the direct-buried insulation pipe.

[0006] In the above-mentioned direct-buried thermal insulation pipe spray winding process, through the setting of the shaping ring, during the spraying process with the spray gun, the convex part of the sprayed polyurethane layer can be corrected and shaped to improve the concentricity, and the concave part can be detected at the same time, so as to detect abnormalities in time, facilitate timely and targeted maintenance, and improve the quality of the finished direct-buried thermal insulation pipe.

[0007] As a further improvement of the present application, during spraying and winding, both ends of the inner steel pipe are left open for a certain distance to facilitate welding of the inner steel pipes of the two direct-buried insulation pipes during subsequent use.

[0008] As a further improvement of the present application, an annular groove is excavated in the middle of the inner wall of the shaping ring, and an annular cavity coaxial with the annular groove is also excavated inside the shaping ring. A recess detection unit is jointly arranged in the annular groove and the annular cavity. The recess detection unit includes a plurality of lead-in units located in the annular groove, an isolation ring located in the annular cavity, an outer convex strip fixedly connected to the outside of the annular groove mouth, and a light sensor and a plurality of LED light sources located in the annular cavity. The plurality of lead-in units are distributed in an annular array, and the plurality of lead-in units are fixedly connected to the outer convex strip.

[0009] As a further improvement of the present application, the outer convex strip is an elastic sealing structure, and the outer convex strip protrudes toward the axis of the shaping ring.

[0010] As a further improvement of the present application, the lead-in unit includes a connecting column fixedly connected to the outer convex strip and a lead-in block fixedly connected to the end of the connecting column, the lead-in block is located in the annular groove, and the lead-in block is in contact with the left and right inner walls of the annular groove, the lead-in block does not contact the inner wall of the annular groove facing the annular cavity, and the lead-in block is a hard magnetic structure.

[0011] As a further improvement of the present application, a plurality of evenly distributed outer arc grooves are bored on the isolation ring, and the plurality of outer arc grooves respectively correspond to the plurality of lead-in units; a plurality of inner arc grooves are bored on the inner wall of the annular cavity toward the axis of the shaping ring, and the plurality of inner arc grooves respectively correspond to the plurality of inner arc grooves; a follower bag is fixedly connected to the inner wall of the outer arc groove away from the inner arc groove; the isolation ring and the follower bag are made of opaque elastic material, and an iron sheet is fixedly inlaid on the follower bag.

[0012] As a further improvement of the present application, the LED light source and the light sensor are respectively fixedly mounted on the left and right inner walls of the annular cavity, the radial span of the inner arc groove is consistent with the radial span of the follower capsule, the lateral span of the inner arc groove is greater than the lateral span of the outer arc groove, and the radius of the follower capsule is greater than the cross-sectional radius of the inner arc groove.

[0013] As another improvement of the present application, two U-shaped plates symmetrical about the isolation ring are fixedly connected inside the annular cavity, and the U-shaped plates are located directly above the axis of the shaping ring. Marking units are provided on both sides of the left and right sides of the isolation ring. The marking unit includes a material storage cavity formed between the U-shaped plate and the inner wall of the annular cavity away from the isolation ring, and a material guide tube fixedly embedded in the shaping ring. The material storage cavity is filled with polyurethane colored powder. Two powder pouring cavities corresponding to the two material guide tubes are also opened inside the shaping ring. The two ends of the material guide tube extend to the inner wall of the annular cavity and the inner wall of the shaping ring respectively.

[0014] As another improved supplement of the present application, the material guide pipe includes a feed section, a discharge section and a material suppression pipe transfer pipe fixedly connected therebetween, the material storage pipe is located in the powder pouring chamber, and the ends of the feed section and the discharge section both extend into the powder pouring chamber, the feed section is communicated with the annular chamber, an electric push rod is fixedly connected between the inner wall of the powder pouring chamber close to the axis of the shaping ring and the transfer pipe, the electric push rod is located at the side of the bottom center of the transfer pipe away from the discharge section, and the electric push rod is connected to the light sensor signal.

[0015] As another improved supplement of the present application, the transfer pipe includes a double-headed arc tube and two changing tubes fixedly connected between the two ends of the double-headed arc tube and the feed section and the discharge section respectively. The double-headed arc tube is a hard fixed structure, and the changing tube and the double-headed arc tube are both flexible structures. The feed section and the discharge section are staggered with each other, and there is a height difference between the two in the natural state.

[0016] In summary, in the above-mentioned direct-buried thermal insulation pipe spraying and winding process, through the setting of the shaping ring, during the spraying process with the spray gun, the convex part of the polyurethane layer after spraying can be corrected and shaped to improve the concentricity, and the concave part can be detected at the same time, so as to detect abnormalities in time, facilitate timely and targeted maintenance, and improve the quality of the finished direct-buried thermal insulation pipe. In addition, in conjunction with the setting of the guide pipe, when the polyurethane is shaped and the depression is detected, when a local depression is detected, the two guide pipes can be triggered to spray powder, thereby limiting the defect location, facilitating subsequent fixed-point repair, and further ensuring the quality of the finished direct-buried thermal insulation pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the process of spraying polyurethane according to the first embodiment of the present application; Figure 2 This is a transverse cross-sectional view of the shaping ring according to the first embodiment of the present application; Figure 3This is a radial cross-sectional view of the shaping ring according to the first embodiment of the present application; Figure 4 for Figure 3 The structural diagram at A in the middle; Figure 5 This is a transverse cross-sectional view of the shaping ring portion of the first embodiment of the present application; Figure 6 This is a schematic structural diagram of a depression detection unit according to a first embodiment of the present application; Figure 7 It is a partial cross-sectional view of the depression detection unit when there is no depression at the corresponding part when the shaping ring of the first embodiment of the present application shapes the polyurethane layer; Figure 8 This is a transverse cross-sectional view of the shaping ring portion of the second embodiment of the present application; Fig. 9 A partial schematic diagram of a marking unit according to a second embodiment of the present application; Fig.10 This is a partial schematic diagram of a material guide tube according to a second embodiment of the present application; Fig.11 This is a partial schematic diagram of the material guide tube when performing recessed marking according to the second embodiment of the present application.

[0018] Description of the numbers in the figure: 1 shaping ring, 101 annular groove, 102 annular cavity, 2 outer convex strip, 3 lead unit, 31 connecting column, 32 lead block, 4 isolating ring, 401 outer arc groove, 402 inner arc groove, 403 follower bag, 61 LED light source, 62 light sensor, 71 powder pouring cavity, 81 feeding section, 82 discharging section, 83 transfer pipe, 831 change-of-direction pipe, 832 double-head arc pipe, 84 electric push rod. DETAILED DESCRIPTION

[0019] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0020] The first implementation method: A spray winding process for a directly buried thermal insulation pipe, wherein the directly buried thermal insulation pipe comprises an inner steel pipe, a polyurethane thermal insulation layer and a polyethylene outer sheath from the inside to the outside, and comprises the following steps: S1. First, grind and clean the inner steel pipe to remove rust and oil stains on the surface, then pass the inner steel pipe through the shaping ring 1 and place it on two sets of rotating rollers, where the inner steel pipe is coaxial with the shaping ring 1, so that the two ends of the inner steel pipe are respectively placed on the two sets of rotating rollers, and the inner steel pipe is driven to rotate continuously by the rotating rollers. An electric slide rail is set in the middle above the two sets of rotating rollers, and the shaping ring 1 is connected to the electric slide rail; S2, such as Figure 1In the figure, a represents the inner steel pipe, b represents the spray gun, and c represents the polyurethane insulation layer that has been sprayed on the surface of the inner steel pipe. The inner steel pipe surface is sprayed with polyurethane by the spray gun, wherein the spray gun is fixedly connected to the shaping ring 1 through a bracket, so that the shaping ring 1 and the spray gun can move synchronously along the electric slide rail. With the rotation of the inner steel pipe and the linear movement of the spray gun, the polyurethane is evenly sprayed on the surface of the inner steel pipe to form a polyurethane insulation layer. When the spray gun moves, the shaping ring 1 moves on the surface of the polyurethane insulation layer, thereby shaping and adjusting the foaming polyurethane insulation layer and synchronously detecting local depressions; S3. When local depressions are detected in the polyurethane insulation layer, targeted treatment can be carried out to fill the depressions, and then winding treatment can be carried out. When no depressions are detected, winding treatment can be carried out directly after foaming. At this time, the strip polyethylene extruded by the extruder is evenly wound around the outside of the polyurethane insulation layer. After cooling, the polyethylene shrinks and tightly wraps around the outside of the polyurethane insulation layer to complete the spray winding of the direct-buried insulation pipe.

[0021] During spraying and winding, both ends of the inner steel pipe are left open for a certain distance to facilitate welding of the inner steel pipes of the two direct-buried insulation pipes in subsequent use.

[0022] It is worth noting that the inner diameter of the shaping ring 1 is consistent with the outer diameter of the target polyurethane insulation layer.

[0023] like Figure 2 The middle part of the inner wall of the shaping ring 1 is provided with an annular groove 101, and an annular cavity 102 coaxial with the annular groove 101 is also provided inside the shaping ring 1. A depression detection unit is provided in the annular groove 101 and the annular cavity 102. The depression detection unit includes a plurality of lead-in units 3 located in the annular groove 101, an isolation ring 4 located in the annular cavity 102, an outer convex strip 2 fixedly connected to the outside of the mouth of the annular groove 101, and a light sensor 62 and a plurality of LED light sources 61 located in the annular cavity 102. The LED light source 61 and the light sensor 62 are respectively fixedly mounted on the annular groove 101 and the annular cavity 102. On the left and right inner walls of the cavity 102, multiple lead units 3 are distributed in a circular array, and the multiple lead units 3 are fixedly connected to the outer convex strip 2. The outer convex strip 2 is an elastic sealing structure, and the outer convex strip 2 protrudes toward the axis of the shaping ring 1. When it moves with the nozzle, the volume of the foamed polyurethane increases and will conflict with the inner wall of the shaping ring 1. When there is a local depression, the corresponding part of the outer convex strip 2 cannot be deformed normally, resulting in a significant difference in the movement range of the lead unit 3 corresponding to the depression and the lead unit 3 in other parts, causing the light sensor 62 to have obvious data changes.

[0024] like Figure 3-5The lead unit 3 includes a connecting column 31 fixedly connected to the outer convex strip 2 and a lead block 32 fixedly connected to the end of the connecting column 31, the lead block 32 is located in the annular groove 101, and the lead block 32 contacts the left and right inner walls of the annular groove 101, and the lead block 32 does not contact the inner wall of the annular groove 101 facing the annular cavity 102, the lead block 32 is a hard magnetic structure, a plurality of uniformly distributed outer arc grooves 401 are cut on the isolation ring 4, and the plurality of outer arc grooves 401 correspond to the plurality of lead units 3 respectively, and the inner wall of the annular cavity 102 facing the axis of the shaping ring 1 is cut with a plurality of inner arc grooves 402, and the plurality of inner arc grooves 402 correspond to the plurality of inner arc grooves 402 respectively, and the inner wall of the outer arc groove 401 away from the inner arc groove 402 is fixedly connected with a follower capsule 403, the isolation ring 4 and the follower capsule 403 are made of opaque elastic material, and the follower capsule 403 is fixedly inlaid with an iron sheet, such as Figure 7 When the corresponding part is convex or the foaming degree is good, under the extrusion of the foamed polyurethane, the outer convex strip 2 is deformed, thereby pushing the lead unit 3 to move toward the isolation ring 4, and the device lead block 32 conflicts with the annular groove 101. At this time, the outer convex strip 2 is also attached to the inner wall of the shaping ring 1. At the same time, due to the magnetic attraction, the lead block 32 will absorb the follower bag 403 to make it close to the inner arc groove 402 and block the inner arc groove 402 and the outer arc groove 401, so that the space on both sides of the isolation ring 4 will be isolated. At this time, the data on the light sensor 62 will disappear, or the data will be very small, such as Figure 6 When there is a local depression, the outer convex strip 2 corresponding to the depression is difficult to deform, resulting in the inability of the guide block 32 to move normally toward the isolation ring 4. At this time, the corresponding outer arc groove 401 and the inner arc groove 402 cannot be completely blocked, so that the spaces on both sides of the isolation ring 4 are connected, and some light will enter the other side, so that there is still light data on the light sensor 62. Based on the data changes of the light sensor 62, the staff can effectively judge whether there is a local depression in the polyurethane insulation layer, which is convenient for subsequent targeted maintenance and improves the quality of the finished product.

[0025] The radial span of the inner arc groove 402 is consistent with the radial span of the follower bag 403, the lateral span of the inner arc groove 402 is greater than the lateral span of the outer arc groove 401, and the radius of the follower bag 403 is greater than the cross-sectional radius of the inner arc groove 402, which effectively ensures that after being subjected to the adsorption force, the follower bag 403 can fully contact the inner arc groove 402, thereby blocking the outer arc groove 401 and the inner arc groove 402.

[0026] In the above-mentioned direct-buried thermal insulation pipe spray winding process, through the setting of the shaping ring 1, during the spraying process with the spray gun, the convex part of the polyurethane layer after spraying can be corrected and shaped to improve the concentricity, and the concave part can be detected at the same time, so as to detect abnormalities in time, facilitate timely and targeted maintenance, and improve the quality of the finished direct-buried thermal insulation pipe.

[0027] The second implementation method: This embodiment adds a marking unit on the basis of the first embodiment, and the rest of the parts are consistent with the first embodiment.

[0028] Figure 8-9 As shown, two U-shaped plates symmetrical to the isolation ring 4 are fixedly connected inside the annular cavity 102, and the U-shaped plates are located just above the axis of the shaping ring 1. Marking units are provided on both sides of the isolation ring 4. The marking units include a material storage cavity formed between the U-shaped plate and the inner wall of the annular cavity 102 away from the isolation ring 4, and a material guide tube fixedly embedded in the shaping ring 1. The material storage cavity is filled with polyurethane colored powder. Two powder pouring cavities 71 corresponding to the two material guide tubes are also excavated inside the shaping ring 1. The two ends of the material guide tube extend to the inner wall of the annular cavity 102 and the shaping ring 1 respectively. The inner wall of the ring 1, the material guide pipe includes a feed section 81, a discharge section 82 and a material suppression pipe transfer pipe 83 fixedly connected therebetween, the material storage pipe is located in the powder pouring chamber 71, and the ends of the feed section 81 and the discharge section 82 extend into the powder pouring chamber 71, the feed section 81 is communicated with the annular chamber 102, an electric push rod 84 is fixedly connected between the inner wall of the powder pouring chamber 71 close to the axis of the shaping ring 1 and the transfer pipe 83, the electric push rod 84 is located at the bottom center of the transfer pipe 83 away from the discharge section 82, and the electric push rod 84 is connected to the light sensor 62 signal, such as Figure 10-11 When a depression is detected outside the polyurethane layer by the light sensor 62, the signal can be fed back to the electric push rod 84, causing it to start working and push the transfer tube 83, thereby increasing the height of its bottom and flipping toward the side of the discharge section 82. At this time, the polyurethane colored powder deposited in the transfer tube 83 in the guide tube will spill out and then fall on the polyurethane layer. The marking units on both sides will simultaneously form marks on the polyurethane layer. After the shaping ring 1 is away from the place, the staff can observe whether there is a mark to intuitively judge whether there is a defect, and can narrow the scope of the defect in the depression based on the two marks. After clearly seeing the mark, the area between the two marks can be observed circumferentially to determine the specific location of the depression, effectively improving the convenience of subsequent targeted maintenance.

[0029] The transfer tube 83 includes a double-headed arc tube 832 and two changing tubes 831 respectively fixedly connected between the two ends of the double-headed arc tube 832 and the feed section 81 and the discharge section 82. The double-headed arc tube 832 is a hard fixed structure, and the changing tube 831 and the double-headed arc tube 832 are both flexible structures. The feed section 81 and the discharge section 82 are staggered with each other, and there is a height difference between the two in the natural state, so that in the natural state, the powder in the electric push rod 84 is not easy to leak into the discharge section 82, thereby reducing the impact on the detection process.

[0030] In summary, in the above-mentioned direct-buried thermal insulation pipe spraying and winding process, through the setting of the shaping ring 1, during the spraying process with the spray gun, the convex part of the polyurethane layer after spraying can be corrected and shaped to improve the concentricity, and the concave part can be detected at the same time, so as to detect abnormalities in time, facilitate timely and targeted maintenance, and improve the quality of the finished direct-buried thermal insulation pipe. In addition, in conjunction with the setting of the guide pipe, when the polyurethane is shaped and the depression is detected, when a local depression is detected, the two guide pipes can be triggered to spray powder, thereby limiting the defect location, facilitating subsequent fixed-point repair, and further ensuring the quality of the finished direct-buried thermal insulation pipe.

[0031] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A spray winding process for a directly buried thermal insulation pipe, wherein the directly buried thermal insulation pipe comprises, from inside to outside, an inner steel pipe, a polyurethane thermal insulation layer and a polyethylene outer sheath, characterized in that: The following steps are involved: S1. First, the inner steel pipe is polished and cleaned to remove rust and oil stains on the surface, and then the inner steel pipe is passed through the shaping ring (1) and placed on two sets of rotating rollers, so that the two ends of the inner steel pipe are respectively placed on the two sets of rotating rollers, and the inner steel pipe is driven to rotate continuously by the rotating rollers. An electric slide rail is arranged in the middle above the two sets of rotating rollers, and the shaping ring (1) is connected to the electric slide rail; S2. Spraying polyurethane on the surface of the inner steel pipe with a spray gun, wherein the spray gun is fixedly connected to the shaping ring (1) through a bracket, so that the shaping ring (1) and the spray gun can move synchronously along the electric slide rail. With the rotation of the inner steel pipe and the linear movement of the spray gun, the polyurethane is evenly sprayed on the surface of the inner steel pipe to form a polyurethane insulation layer. When the spray gun moves, the shaping ring (1) moves on the surface of the polyurethane insulation layer, thereby shaping and adjusting the foaming polyurethane insulation layer and synchronously detecting local depressions; S3. When local depressions are detected in the polyurethane insulation layer, targeted treatment can be carried out to fill the depressions, and then winding treatment can be carried out. When no depressions are detected, winding treatment can be carried out directly after foaming. At this time, the strip polyethylene extruded by the extruder is evenly wound around the outside of the polyurethane insulation layer. After cooling, the polyethylene shrinks and tightly wraps around the outside of the polyurethane insulation layer to complete the spray winding of the direct-buried insulation pipe.

2. A spray winding process for direct buried thermal insulation pipe according to claim 1, characterized in that: During spraying and winding, both ends of the inner steel pipe are left open for a certain distance to facilitate welding of the inner steel pipes of the two direct-buried insulation pipes in subsequent use.

3. A spray winding process for direct buried thermal insulation pipe according to claim 1, characterized in that: An annular groove (101) is bored in the middle of the inner wall of the shaping ring (1), and an annular cavity (102) coaxial with the annular groove (101) is also bored inside the shaping ring (1). A depression detection unit is provided in both the annular groove (101) and the annular cavity (102). The depression detection unit comprises a plurality of lead-out units (3) located in the annular groove (101), an isolation ring (4) located in the annular cavity (102), an outer convex strip (2) fixedly connected to the outside of the mouth of the annular groove (101), and a light sensor (62) and a plurality of LED light sources (61) located in the annular cavity (102). The plurality of LED light sources (61) and the light sensor (62) are respectively fixedly mounted on the left and right inner walls of the annular cavity (102). The plurality of lead-out units (3) are distributed in an annular array, and the plurality of lead-out units (3) are all fixedly connected to the outer convex strip (2).

4. A spray winding process for direct buried thermal insulation pipe according to claim 3, characterized in that: The outer convex strip (2) is an elastic sealing structure, and the outer convex strip (2) protrudes towards the axis of the shaping ring (1).

5. A spray winding process for direct buried thermal insulation pipe according to claim 4, characterized in that: The lead piece unit (3) comprises a connecting column (31) fixedly connected to the outer convex strip (2) and a lead piece block (32) fixedly connected to the end of the connecting column (31); the lead piece block (32) is located in the annular groove (101), and the lead piece block (32) contacts the left and right inner walls of the annular groove (101); the lead piece block (32) does not contact the inner wall of the annular groove (101) facing the annular cavity (102); and the lead piece block (32) is a hard magnetic structure.

6. A spray winding process for direct buried thermal insulation pipe according to claim 5, characterized in that: The isolation ring (4) is provided with a plurality of evenly distributed outer arc grooves (401), and the plurality of outer arc grooves (401) respectively correspond to the plurality of lead-in units (3). The inner wall of the annular cavity (102) facing the axis of the shaping ring (1) is provided with a plurality of inner arc grooves (402), and the plurality of inner arc grooves (402) respectively correspond to the plurality of inner arc grooves (402). A follower bag (403) is fixedly connected to the inner wall of the outer arc groove (401) away from the inner arc groove (402). The isolation ring (4) and the follower bag (403) are made of opaque elastic material, and an iron sheet is fixedly embedded on the follower bag (403).

7. A spray winding process for direct buried thermal insulation pipe according to claim 6, characterized in that: The radial span of the inner arc-shaped groove (402) is consistent with the radial span of the follower bag (403), the lateral span of the inner arc-shaped groove (402) is greater than the lateral span of the outer arc-shaped groove (401), and the radius of the follower bag (403) is greater than the cross-sectional radius of the inner arc-shaped groove (402).

8. The spray winding process for direct buried thermal insulation pipe according to claim 6 is characterized by: Two U-shaped plates symmetrical to the isolation ring (4) are fixedly connected inside the annular cavity (102), and the U-shaped plates are located directly above the axis of the shaping ring (1). The left and right sides of the isolation ring (4) are provided with marking units, and the marking units include a material storage cavity formed between the U-shaped plates and the inner wall of the annular cavity (102) away from the isolation ring (4), and a material guide tube fixedly embedded in the shaping ring (1). The material storage cavity is filled with polyurethane colored powder. The shaping ring (1) is also provided with two powder pouring cavities (71) corresponding to the two material guide tubes, and the two ends of the material guide tube extend to the inner wall of the annular cavity (102) and the inner wall of the shaping ring (1), respectively.

9. A spray winding process for direct buried thermal insulation pipe according to claim 7, characterized in that: The material guide pipe comprises a feed section (81), a discharge section (82) and a material suppression pipe transfer pipe (83) fixedly connected therebetween. The material storage pipe is located in the powder pouring chamber (71), and the ends of the feed section (81) and the discharge section (82) both extend into the powder pouring chamber (71). The feed section (81) is communicated with the annular chamber (102). An electric push rod (84) is fixedly connected between the inner wall of the powder pouring chamber (71) close to the axis of the shaping ring (1) and the transfer pipe (83). The electric push rod (84) is located at the bottom center of the transfer pipe (83) on a side away from the discharge section (82). The electric push rod (84) is connected to the light sensor (62) for signal connection.

10. A spray winding process for directly buried thermal insulation pipe according to claim 9, characterized in that: The transfer pipe (83) comprises a double-ended arc pipe (832) and two direction-changing pipes (831) respectively fixedly connected between the two ends of the double-ended arc pipe (832) and the feed section (81) and the discharge section (82); the double-ended arc pipe (832) is a hard, fixed structure; the direction-changing pipes (831) and the double-ended arc pipe (832) are both flexible structures; the feed section (81) and the discharge section (82) are mutually offset, and in a natural state, there is a height difference between the two.

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