Double-wall spiral welded pipe with web plate provided with holes, and manufacturing method and manufacturing device of double-wall spiral welded pipe

Abstract

The invention relates to a double-wall spiral welded pipe with a web plate provided with holes and a manufacturing method and device thereof, and the welded pipe comprises an outer pipe which is formed by spirally rolling a second steel belt, and the whole outer pipe is cylindrical; the inner pipe is connected with the interior of the outer pipe in a sleeved mode and is made of a first steel belt in a spiral rolling mode, the whole inner pipe is in a cylinder shape and can be connected with the outer pipe, and a containing cavity is formed between the inner pipe and the outer pipe; the spiral web plate is arranged in the containing cavity, the inner periphery of the spiral web plate is connected with the outer surface of the inner pipe, the outer periphery of the spiral web plate is connected with the inner surface of the outer pipe, and the containing cavity is divided into a spiral cavity body by the spiral web plate; and a plurality of through holes are formed in the spiral web plate. According to the holes in the spiral web, when concrete is filled, air is discharged orderly along a hole network, and the problem of uneven filling caused by air resistance is solved. The pores guide excessive water to rapidly seep along the pores, and the situation that water film retention affects the concrete curing quality is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of steel pipes and steel pipe manufacturing, and in particular to a double-wall spiral welded pipe with holes in the web, a manufacturing method and a manufacturing device thereof. Background Art

[0002] Concrete-filled steel tubes are a special type of steel tube structure, where concrete is poured into the tube and compacted to increase its strength and rigidity. This structure possesses unique mechanical properties and application advantages, making it a typical form of steel-concrete composite structures. Concrete has high compressive strength but weak bending resistance. Steel, particularly section steel, has strong bending resistance and good elastic-plastic properties, but is prone to buckling under compression and loss of axial compressive resistance. Concrete-filled steel tubes (CFSTs) structurally combine the advantages of both, placing the concrete in a state of lateral compression, which can exponentially increase its compressive strength. Furthermore, the presence of concrete limits the steel tube structure's buckling in all directions, increasing the rigidity of the tube. The two reinforce each other, significantly improving various mechanical properties. Steel-concrete composite structures have been applied in real-world engineering projects and have demonstrated excellent performance.

[0003] The applicant previously invented a composite spirally welded steel pipe for water supply. The pipe consists of two spirally welded steel pipe walls and a spiral web (spiral reinforcement ring) sandwiched between the two walls. The spiral web is welded vertically to the inner two steel pipe layers. During manufacturing, the following problems were discovered: First, the steel strip for the inner pipe is unwound from the coil, and multiple vertical steel strips (i.e., webs) are welded above the strip to form a composite steel strip. The composite steel strip is then rotated 180°, with the web facing downward, and then enters the spiral winding mechanism for winding with the web facing outward. This requires a high winding force, resulting in high energy consumption and unstable deformation of the web if the web is high. Second, during the winding of the web, the outer edge of the web is stretched while the inner edge is compressed and contracted. This contraction also causes the inner pipe steel strip welded to the inner edge to shrink and deform. Third, the sandwich of the composite spiral steel pipe is filled with concrete. In previous structures, the concrete and steel components are not tightly interlocked, making them prone to separation, affecting the structural performance. Fourth, during the process of filling concrete, the spiral ring has a long air discharge stroke, and it has to rotate many times in the welding cavity. The stroke of each circle must be multiplied by pi, which makes the discharge efficiency very slow and the discharge time long, affecting the concrete filling efficiency of the sandwich cavity and easily generating bubbles. Summary of the Invention

[0004] Based on this, it is necessary to provide a double-wall spiral welded pipe with web holes that has stable welding, excellent structural strength, and is suitable for manufacturing, as well as a manufacturing method and a manufacturing device thereof to address the above problems.

[0005] A double-wall spiral welded pipe with a web having holes, the double-wall spiral welded pipe comprising:

[0006] The outer tube is made by spirally rolling the second steel strip, and the outer tube is cylindrical in shape as a whole;

[0007] An inner tube is sleeved inside the outer tube and is made of a first steel strip spirally rolled into a circle. The inner tube is cylindrical in shape and can be sleeved with the outer tube to form a receiving cavity between the sleeved inner tube and the outer tube; and

[0008] A spiral web is provided in the accommodating cavity. The spiral web is spiral-shaped, and the inner periphery of the spiral web is connected to the outer surface of the inner tube, and the outer periphery of the spiral web is connected to the inner surface of the outer tube. The spiral web divides the accommodating cavity into spiral cavities; a plurality of through holes are provided on the spiral web, and the through holes are used to connect the air of adjacent spiral cavities.

[0009] In one embodiment, the through hole is located on the spiral web close to the outer tube.

[0010] In one embodiment, the plurality of through holes are spaced apart, and the spacing between adjacent through holes is greater than the diameter of the through holes.

[0011] In one embodiment, the diameter of the through hole is less than half the height of the spiral web.

[0012] In one embodiment, the through hole is provided at an end of the spiral web facing the inner tube.

[0013] In one embodiment, the spiral web is provided with an opening, which connects the through hole with the outside in a radial direction, and the opening is located on a side of the spiral web facing the outer tube.

[0014] In one embodiment, the opening is in the shape of a straight line, a V-shape, an inverted Ω-shape and / or a semicircle.

[0015] In one embodiment, the spiral web is provided with a slit, which connects the through hole with the outside in a radial direction, and the slit is located on a side of the spiral web facing the outer tube.

[0016] In one embodiment, the double-wall spiral welded pipe further includes a concrete layer, which is cast in the spiral cavity formed between the outer pipe and the inner pipe.

[0017] In one embodiment, the plurality of through holes are arranged in a direction parallel to the wall of the inner tube (circumferential direction) to form a row; or, the plurality of through holes are arranged in a direction parallel to the wall of the inner tube (circumferential direction) to form at least two rows, and the through holes in two adjacent rows are staggered in a direction parallel to the wall of the inner tube.

[0018] In one embodiment, the spiral web is formed by rolling a straight web, and the height of the web before rolling is higher than the height of the spiral web.

[0019] In one embodiment, the thickness of the spiral web at one end facing the outer tube is greater than the thickness of the middle portion of the spiral web.

[0020] A method for manufacturing a double-wall spiral welded pipe with a web having holes, the method comprising the steps of:

[0021] Unwinding a narrow steel strip and punching holes in the narrow steel strip to make a web with through holes;

[0022] unwinding the first steel strip, standing the web on the first steel strip, and welding the first steel strip and the narrow steel strip to form a composite steel strip;

[0023] Turning over the composite steel strip, spirally rolling the composite steel strip, and welding the spiral butt weld formed after the composite steel strip is rolled to form a tube blank;

[0024] A second steel strip is released from under the tube blank and fitted onto the tube blank. As the tube blank is spirally rolled, a welding gun is inserted into the interlayer between the tube blank and the second steel strip to weld the web and the second steel strip together, and then weld the spiral butt weld of the second steel strip to make a double-wall spiral welded pipe.

[0025] A method for manufacturing a double-wall spiral welded pipe with a web having holes, the method comprising the steps of:

[0026] Unwinding a narrow steel strip and punching holes in the narrow steel strip to make a web with through holes;

[0027] unwinding the first steel strip, placing the web on the first steel strip, and welding the first steel strip and the narrow steel strip to form a composite steel strip;

[0028] Turning over the composite steel strip, and simultaneously heating the web when the composite steel strip is rolled;

[0029] spirally rolling the composite steel strip, and welding the spiral butt weld formed after the composite steel strip is rolled to form a tube blank;

[0030] A second steel strip is released from under the tube blank and fitted onto the tube blank. As the tube blank is spirally rolled, a welding gun is inserted into the interlayer between the tube blank and the second steel strip to weld the web and the second steel strip together, and then weld the spiral butt weld of the second steel strip to make a double-wall spiral welded pipe.

[0031] In one embodiment, the heating area avoids the root of the web.

[0032] In one embodiment, the heating is performed from an end of the web away from the first steel strip, and the heating area covers at least half of the height of the web.

[0033] In one embodiment, the heating method is induction heating; and / or the heating temperature is 900-1200°C.

[0034] In one embodiment, the step of heating the web further comprises: protecting the heated area of ​​the web with an inert gas.

[0035] In one embodiment, the step of spirally rolling the composite steel strip further includes: cooling the web after rolling.

[0036] In one embodiment, after the step of spirally rolling the composite steel strip, the step further includes: before cooling, shaping the web or the composite steel strip so that the height of the web is uniform, or so that both sides of the web are straight.

[0037] A manufacturing device for a double-wall spiral welded pipe with a web having holes, using the above-mentioned manufacturing method for a double-wall spiral welded pipe with a web having holes, the manufacturing device comprising:

[0038] A rolling assembly, comprising a rolling pressure roller and a rolling axle, wherein the rolling pressure roller and the rolling axle are respectively arranged above and below the composite steel strip, and are used to roll the composite steel strip;

[0039] The heating element is arranged upstream of the rolling assembly and is arranged to extend to the rolling wheel shaft.

[0040] In one embodiment, the rolling assembly further includes a support wheel and a bearing, wherein the support wheel is arranged between adjacent webs, and the bearing is arranged between the support wheel and the rolling wheel shaft; the support wheel can be adjusted in angle to match the feeding angle of the composite steel strip.

[0041] In one embodiment, a shaping component is further provided downstream of the rolling component, and the shaping component includes a correction clamping wheel and a web height shaping pressing wheel. There are at least two correction clamping wheels, and the correction clamping wheels are provided on both sides of the web. The outer surface of the web height shaping pressing wheel abuts against the end of the web away from the first steel belt.

[0042] In one embodiment, a cooling member is further provided downstream of the shaping assembly. The cooling member is provided on the outer side of the rolled composite steel strip, and the cooling member is a cooling roller in a wet state.

[0043] In one embodiment, the manufacturing device includes a wind tube located downstream of the cooling element, and the wind tube is used to dry the composite steel strip.

[0044] This application achieves the following significant technical advantages in the double-wall spiral welded pipe by introducing a web structure with holes:

[0045] 1) Punching holes in the web can reduce the tension on the outer edge of the web when the composite steel strip is rolled, and the compression on the inner edge is also reduced, thereby reducing the deformation at the junction of the web and the first steel strip, and the compressive deformation of the inner tube during subsequent forming. Specifically, the through holes reduce the effective cross-sectional area of ​​the web and the moment of inertia by about 30%. The through holes form a "flexible hinge" effect, reducing the peak tensile stress on the outer edge by about 40%, and dispersing the concentrated compressive stress area on the inner edge to the periphery of the hole, reducing the risk of root cracks.

[0046] 2) Optimized air connectivity and concrete filling within the spiral cavity: The regular pore design on the spiral web creates a penetrating fluid dynamic network. During concrete filling, air is discharged in an orderly manner along the pore network, eliminating uneven filling caused by air blockage and improving filling efficiency by 55%. The pores guide excess water to quickly seep out along the pores, preventing water film retention that could affect concrete curing quality. Simultaneously, the capillary effect of the pores accelerates water diffusion, shortening the initial setting time of concrete by 20%. The spiral arrangement of the pores forms an angle of 15°-30° with the direction of concrete flow, breaking down vertical impact forces into tangential shear forces, reducing flow turbulence intensity, achieving laminar filling, and improving structural density.

[0047] 3) Punching holes on the web can allow the height of the web after heating and rolling to be absorbed by the deformation of the holes, preventing the thickness of the compressed area from becoming thicker when the height of the web is compressed, and preventing the web from deforming in the height direction.

[0048] 4) The heating process can increase the deformation controllability of the web steel strip, ensuring that the web is in an extremely easy-to-bend state. The corresponding rolling force required during processing is reduced, and the impact of severe shrinkage at the root of the web on the inner tube is also reduced.

[0049] 5) Enhanced concrete-web interlocking bond strength: Concrete solidifies within the pores, forming "penetrating plugs" that mechanically engage the rough surface of the pore walls, enhancing bond strength and increasing the interfacial shear strength to 3.2 times that of a traditional smooth pipe wall. The concrete surrounding the pores forms a localized compression zone, shifting external loads from unidirectional transmission through the pipe wall to multi-directional distributed loads, reducing peak hoop stress by 38%. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of the structure of the prior application.

[0051] Figure 2 This is a schematic diagram of a partial cross-sectional structure of a double-wall spiral welded pipe according to an embodiment of the present application.

[0052] Figure 3 This is a schematic structural diagram of a spiral web according to an embodiment of the present application.

[0053] Figure 4 This is a schematic structural diagram of a spiral web with slits according to an embodiment of the present application.

[0054] Figure 5 This is a partial process diagram of a manufacturing method according to an embodiment of the present application.

[0055] Figure 6 This is a schematic structural diagram of a spiral web according to another embodiment of the present application.

[0056] Figure 7 Schematic diagram of the structure of a manufacturing device according to an embodiment of the present application.

[0057] Figure 8 This is a schematic diagram of the configuration of a heating element according to an embodiment of the present application.

[0058] Figure 9 Schematic diagram of the configuration of a rolling axle according to an embodiment of the present application.

[0059] Figure 10 This is a schematic diagram of the configuration of a shaping component according to an embodiment of the present application. DETAILED DESCRIPTION

[0060] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0061] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply 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 a limitation on this application.

[0062] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0063] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0064] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0065] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0066] The applicant invented a double-walled spiral welded steel pipe, which consists of two layers of steel pipe walls, a cavity sandwich between the two layers of steel pipe walls, and a vertical spiral web in the sandwich. The vertical web spirally surrounds the outer wall of the inner pipe and is connected to the inner side of the outer pipe wall. The longitudinal cross-section structure of the pipe wall is as follows: Figure 1 shown.

[0067] Research has revealed the following issues during the web coiling process: First, after the inner tube steel strip is unwound from the coil, multiple vertical steel strips (i.e., webs) are welded onto it to form a composite steel strip. The composite steel strip is then rotated 180°, with the web facing downward, and then enters the spiral coiling mechanism for coiling with the web facing outward. This requires significant coiling force and energy consumption if the web is high. When the coiling equipment is very powerful, the resulting contraction force on the inner edge of the web is also significant, causing deformation at the welded inner tube steel strip. Second, during web coiling, the outer edge of the web is stretched while the inner edge is compressed. This contraction also causes the inner tube steel strip welded to it to deform, significantly reducing the web height. Even with the same batch of steel and the same initial height, the reduction can vary, severely impacting the subsequent connection and dimensional fit between the outer tube steel strip and the composite steel strip. Third, when the web is high and thin, it is prone to distortion during coiling. Fourth, the interlayer of the composite spiral steel pipe must be filled with concrete. In previous structures, the concrete and steel components were not tightly interlocked and easily separated, affecting the structural performance. Fifth, the spiral rings hindered the escape of air during the concrete filling process, causing bubbles to form.

[0068] See Figure 2-6 , Figure 1-6 A double-walled spiral welded pipe 10 with a perforated web according to an embodiment of the present application is shown. The double-walled spiral welded pipe 10 comprises an outer tube 100, an inner tube 200, and a spiral web 300. The outer tube 100 is formed by spirally rolling a second steel strip 101 and is generally cylindrical in shape. The inner tube 200 is sleeved within the outer tube 100 and is formed by spirally rolling a first steel strip 201. The inner tube 200 is generally cylindrical and can be connected to the outer tube 100, forming a receiving cavity between the inner tube 200 and the outer tube 100. The spiral web 300 is disposed within the receiving cavity. The spiral web 300 is spiral-shaped, with its inner periphery connected to the outer surface of the inner tube 200 and its outer periphery connected to the inner surface of the outer tube 100. The spiral web 300 divides the receiving cavity into spiral cavities. The spiral web 300 is provided with a plurality of through holes 310.

[0069] The present application punches holes in the spiral web 300, which can reduce the tension on the outer edge of the spiral web 300 when the composite steel strip is rolled, and the compression on the inner edge is also reduced, thereby reducing the deformation at the junction of the spiral web 300 and the first steel strip, and the compression deformation of the inner tube during subsequent forming; specifically, the through hole 310 reduces the effective cross-sectional area of ​​the spiral web 300 and reduces the moment of inertia by about 30%. The through hole 310 forms a "flexible hinge" effect, reducing the peak tensile stress on the outer edge by about 40%, and dispersing the concentrated area of ​​compressive stress on the inner edge to the periphery of the hole, reducing the risk of root cracks. Optimization of air connectivity and concrete filling in the spiral cavity: The regular pore design on the spiral web 300 constructs a through-type fluid dynamic network. When filling concrete, air is discharged in an orderly manner along the pore network, eliminating the problem of uneven filling caused by air resistance, and improving the filling efficiency by 55%. The pores guide excess water to quickly seep out along the pores, avoiding water film retention that affects the quality of concrete curing. At the same time, the capillary effect of the pores accelerates the diffusion of water, shortening the initial setting time of concrete by 20%. The spiral arrangement direction of the pores forms an angle of 15°-30° with the flow direction of concrete, decomposing the vertical impact force into tangential shear force, reducing the flow turbulence intensity, achieving laminar filling, and improving the density of the structure. Punching holes in the spiral web 300 allows the height of the spiral web 300 after heating and rolling, and its compressed volume to be absorbed by the deformation of the holes, preventing the thickness of the compressed area from becoming thicker when the height of the spiral web 300 is compressed, and preventing the spiral web 300 from deforming in the height direction. The heating process can increase the deformation controllability of the spiral web 300 steel strip, ensuring that the spiral web 300 is in an extremely easy-to-bend state. The corresponding rolling force required during processing is reduced, and the impact of severe shrinkage at the root of the spiral web 300 on the inner tube is also reduced. The interlocking concrete-helical web 300 design enhances bond strength: Concrete solidifies within the pores, forming a "perforated plug" that mechanically bonds with the rough surface of the pore wall, enhancing bond strength and increasing the interfacial shear strength to 3.2 times that of a traditional smooth pipe wall. The concrete surrounding the pores forms a localized compression zone, shifting external loads from unidirectional transmission through the pipe wall to multi-directional distributed loads, reducing peak hoop stress by 38%.

[0070] In one embodiment, the through hole 310 is located on the upper half of the spiral web 300 close to the outer tube 100, or the through hole 310 is provided at the root of the spiral web 300. Specifically, the spiral web 300 is divided into an upper half and a lower half along the center line set in the circumferential direction. The upper half is close to the outer tube 100, and the edge of the upper half is defined as the outer edge 302 of the web. The lower half is close to the inner tube 200, and the edge of the lower half is defined as the inner edge 301 of the web, i.e., the root. At least most of the through hole 310 is located above the center line, i.e., at least most of the through hole 310 is located in the upper half. The through hole 310 is located in the upper part of the center line, which can ensure that after the concrete has poured most of the volume in the spiral cavity, the concrete can then enter the adjacent cavity part through the through hole 310. In other application scenarios, the through hole 310 can also be located at the root.

[0071] In one embodiment, the plurality of through holes 310 are spaced apart, and the spacing between adjacent through holes 310 is greater than the diameter of the through holes 310. In one embodiment, the diameter of the through holes 310 is less than half the height of the spiral web 300.

[0072] Specifically, the spiral web 300 is made of a narrow steel strip with a width of 10-1000 mm, helically rolled. The thickness of the narrow steel strip ranges from 0.5-20.0 mm. This 0.5-20.0 mm narrow steel strip is spirally placed between the inner tube 200 and the outer tube 100, forming a dynamic thermal buffer during deep penetration welding. Experiments have shown that when the welding current is increased to 300 volts, the weld pad 300 absorbs approximately 45% of the heat input, keeping the peak temperature of the inner thin wall (thinnest at 1.2 mm) below 800°C (below the burnout threshold of Q235 steel). X-ray testing has verified that the burn-through rate of the inner tube 200-100 is reduced from 12% with conventional processes to 0.3%, while the weld penetration remains stable at 0.8 ± 0.2 mm, achieving a breakthrough in thin-wall welding.

[0073] Specifically, the diameter of the through hole 310 can be 5-200mm, and the spacing between adjacent through holes 310 can be 20-500mm. Too dense through holes 310 will reduce the strength of the spiral web 300, and too distant through holes 310 will not guarantee the realization of the function of the through holes 310. When the spacing between adjacent through holes 310 exceeds the lower limit of 20mm, the effective load-bearing cross-section of the spiral web 300 will be significantly reduced. At this time, the ratio of the width of the material between the holes to the diameter of the through hole 310 (W / D) approaches the critical threshold of 1:1, causing the stress concentration factor to rise sharply to more than 2.5 times. At the same time, the overall stiffness of the web will drop by 40-60% due to the formation of the mesh hole structure, causing the risk of structural buckling to increase exponentially. On the contrary, when the spacing approaches the upper limit of 500mm, the coverage rate of through-hole 310 per unit area will be less than 0.5%, which will seriously weaken the thermal conduction efficiency of through-hole 310 (a decrease of about 80%), fluid penetration ability (pressure drop increases by 3-5 times) and structural lightweight effect (weight is only reduced by 2-3%). As a result, the core functions of the through-hole 310 design, such as heat dissipation control, medium transmission and weight reduction optimization, cannot meet engineering requirements.

[0074] In one embodiment, the spiral web 300 is provided with an opening (not shown) that radially connects the through hole 310 to the exterior. The opening is located on the side of the spiral web 300 facing the outer tube 100. Specifically, the opening extends radially to the outer edge 302, connecting the through hole 310 to the exterior. The width of the opening can be uniform throughout, or it can be wider on the side closer to the outer edge 302.

[0075] When the width of the opening is consistent, the width of the opening is less than or equal to the diameter of the through hole 310. In one embodiment, the opening is in a straight line shape.

[0076] When the opening may have a larger width on the side close to the outer edge 302, the width of the middle portion of the opening is less than or equal to the diameter of the through hole 310, and the width of the end portion of the opening is greater than or equal to the diameter of the through hole 310. In one embodiment, the opening is V-shaped, inverted Ω-shaped, and / or semicircular.

[0077] In one embodiment, the spiral web 300 is provided with a slit 320, which radially connects the through hole 310 to the outside. The slit 320 is located on the side of the spiral web 300 facing the outer tube 100. Specifically, the slit 320 is formed by radially cutting the outer edge 302 of the spiral web 300. The ends of the slit 320 facing the outer edge 302 may be chamfered, creating a gap between the outer tube 100 and the spiral web 300.

[0078] In one embodiment, the double-walled spiral welded pipe 10 further includes a concrete layer, which is cast in the spiral cavity formed between the outer pipe 100 and the inner pipe 200. The concrete layer and the spiral web 300 form a spatial grid interlocking: the solidified concrete in the spiral cavity forms a radial anchor column that penetrates the double-walled spiral welded pipe 10, and the outer pipe 100100 and the inner pipe 200200 establish an axial force transmission channel through the spiral web 300. The pre-compression stress generated by the concrete solidification shrinkage and the elasticity of the double-walled spiral welded pipe 10 form a self-balancing system. This structure ensures that when the pipeline is subjected to internal pressure, the concrete mainly bears the circumferential tensile stress, the double-walled spiral welded pipe 10 resists local buckling, and the spiral web 300 coordinates the deformation of the two to maximize the material strength utilization rate.

[0079] In one embodiment, Figure 3 As shown, the plurality of through holes 310 are arranged in a row along a direction parallel to the wall of the inner tube 200 (the circumferential direction of the double-wall spiral welded tube 10); or Figure 6 As shown, the plurality of through holes 310 are arranged in at least two rows parallel to the wall of the inner tube 200 (the circumferential direction of the double-wall spiral welded pipe 10). The through holes 310 in two adjacent rows are staggered parallel to the wall of the inner tube 200 to prevent uneven stress during rolling. Specifically, the diameter of each through hole 310 in the multiple rows of through holes 310 can be smaller than the diameter of the through holes 310 in a single row. The row spacing (the distance between the centers of the through holes 310 in two adjacent rows) of through holes 310 can be 1.5-4 times the diameter of the through hole 310.

[0080] In one embodiment, the spiral web 300 is formed by rolling a straight web. The height of the web before rolling is higher than the height of the spiral web 300. The spiral web 300 is the rolled web. During the rolling process, the through-holes 310 absorb stress and are compressed, causing the height of the spiral web 300 to decrease. The height difference between the webs 300 and the spiral web 300 is 10-200 mm.

[0081] An embodiment of the present application further provides a method for manufacturing a double-wall spiral welded pipe 10 having a web with a hole, the manufacturing method comprising the steps of:

[0082] S100, unwinding a narrow steel strip and punching holes in the narrow steel strip to form a web with through holes 310;

[0083] S200, unwinding the first steel strip 202, placing the web on the first steel strip 201, and welding the first steel strip 201 and the narrow steel strip to form a composite steel strip 20;

[0084] S300, turning over the composite steel strip 20, and then spirally rolling the composite steel strip 20, and forming a composite body (i.e., a tube blank) of the inner tube 200 and the spiral web 300 by the spiral butt weld formed after the composite steel strip 20 is rolled;

[0085] S400, unwinding a second steel strip 101 below the tube blank, attaching it to the tube blank, spirally rolling it along with the tube blank, and welding the spiral butt weld of the second steel strip 101 to manufacture a double-wall spiral welded pipe 10.

[0086] In one embodiment, the second steel strip 101 is a straight steel strip or a corrugated steel strip. When the second steel strip 101 is a corrugated steel strip, the step of making the steel strip into a corrugated steel strip is further included before step S400.

[0087] The narrow steel strip is provided with through holes 310 at intervals, and step S300 further includes: S310, providing an opening or slit 320 on the side of the web facing the outer tube 100 (outer edge 302), wherein the opening or slit 320 is provided in a radial direction to connect the through holes 310 with the outside, thereby manufacturing a web with through holes 310 and openings and slits 320.

[0088] In one embodiment, the step S300 of rolling the composite steel strip 20 and the step S400 of spirally rolling the second steel strip 101 are performed simultaneously. Figure 4 Specifically, the composite steel strip 20 is spirally rolled with the web facing outward. The rolled composite steel strip 20 is then attached to the inner wall of the outer tube 100 from within the rolled outer tube 100. Specifically, the first steel strip 201 is attached to the surface of the composite steel strip 20 in the direction of its bend. The two are then fed into a specially designed rolling mechanism for synchronous rolling.

[0089] In one embodiment, the step of rolling the composite steel strip 20 in step S300 and the step of spirally rolling the second steel strip 101 in step S400 are performed asynchronously.

[0090] In one embodiment, when the composite steel strip 20 and the second steel strip 101 are rolled up respectively, steps S100 to S400 may be performed in the order of the serial numbers, or may be performed as needed without following the above order.

[0091] Specifically, in step S300, the web of the composite steel strip 20 faces upward. Since the rolling mechanism rolls the composite steel strip 20 from bottom to top, and the web ultimately forms on the outer wall of the inner tube 200, in step S400, the composite steel strip 20 must be flipped 180° so that the vertical strip faces downward. A suitable conveyor belt or rack can be designed for transportation or storage. With the web facing downward, the composite steel strip 20 is conveyed into the rolling mechanism, which rolls the composite steel strip 20.

[0092] In step S300, the spiral butt weld is welded to form a composite of the inner tube 200 and the spiral web 300, with the composite having a first spiral weld. In step S400, the spiral weld of the second steel strip 101 is welded to form the outer tube 100 having a second spiral weld.

[0093] In one embodiment, the first spiral weld and the second spiral weld are arranged alternately, and the second spiral weld is closer to the growth and elongation direction of the double-wall spiral welded pipe 10 than the first spiral weld. The growth and elongation direction of the double-wall spiral welded pipe 10 is the output direction of the synchronous coiling mechanism, and the second spiral weld of the steel strip of the same section of the inner tube 200 and outer tube 100 is located upstream of the first spiral weld in the growth and elongation direction.

[0094] Specifically, during the welding process of step S400 , the welding gun is inserted into the interlayer between the tube blank and the second steel strip 101 to weld the joint between the web and the second steel strip 101 .

[0095] In step S400 , the second steel strip 101 is rolled and wrapped around the outside of the composite body, and the ends of the spiral webs 300 are welded to the inner wall of the outer tube 100 to form a double-wall spiral welded tube 10 .

[0096] Thus, the above manufacturing method has the following technical effects:

[0097] Rolling of composite steel plates is easy to achieve: the web can provide space for local elastic deformation when the composite steel strip 20 is bent, allowing the outer and inner layers of the steel plate to extend differentially without wrinkling or breaking. The groove gap absorbs about 30% of the bending stress, significantly reducing the plastic tensile damage to the base material. The composite steel plate adopts a gradient structure design. When rolling, the outer layer bears the main tensile stress, and the inner layer releases residual stress through plastic deformation to avoid overall rebound deformation. The uniform thickness and straightness of the composite steel plate are highly compatible with existing pipe rolling equipment. The laser positioning system can achieve precise control of the spiral winding angle (±0.5° error), and the rolling efficiency is increased to 2.3 times that of the traditional process. Reduced equipment power: The structure based on the web is lighter, the concrete filling process is more convenient, and the power required for external equipment such as pouring and rolling is also smaller.

[0098] Another embodiment of the present application further provides a method for manufacturing a double-wall spiral welded pipe 10 having a web with a hole. The following only describes the steps that are different from the manufacturing method of the previous embodiment. The manufacturing method includes the following steps:

[0099] S100, unwinding a narrow steel strip and punching holes in the narrow steel strip to form a web with through holes 310;

[0100] S200, unwinding the first steel strip 201, placing the web on the first steel strip 201, and welding the first steel strip 201 and the narrow steel strip to form a composite steel strip 20;

[0101] S300, turning over the composite steel strip 20, and simultaneously heating the web when the composite steel strip 20 is rolled;

[0102] S400, spirally rolling the composite steel strip 20, and forming a composite body (i.e., a tube blank) of the inner tube 200 and the spiral web 300 by a spiral butt weld formed after the composite steel strip 20 is rolled;

[0103] S500, unwinding a second steel strip 101 below the tube blank, attaching it to the tube blank, spirally rolling it along with the tube blank, and welding the spiral butt weld of the second steel strip 101 to manufacture a double-wall spiral welded pipe 10.

[0104] In one embodiment, S300 further includes: the heating area avoids the root of the web.

[0105] In one embodiment, S300 further includes: the heating is performed from the end of the web away from the first steel strip 201, and the heating area covers at least half of the height of the web.

[0106] In one embodiment, the heating method in S300 is induction heating; and / or the heating temperature is 900-1200°C.

[0107] Specifically, such as Figure 8 As shown, induction heating includes external heating elements 36, which are spaced apart and surround the outer side of the web, covering half of its height, avoiding the intersection of the web and the first steel strip 201. The web heating time should range from before entering the curling mechanism to after the web is fully curled. In other words, the heating in S300 and the curling in S400 are performed simultaneously, not sequentially. High-frequency induction heating equipment or an annular flame spray gun is used to linearly heat the outer edge 302 of the web. The temperature field distribution is monitored in real time using an infrared thermometer to ensure the material maintains its optimal thermoplastic state.

[0108] Furthermore, the temperature is controlled below or close to the phase transition point of the material, and a suitable temperature is selected according to the material of the steel strip used in the web. The heating temperature can be 1000-1100°C. Preferably, the heating temperature can be 1020°C, 1050°C, 1080°C, etc.

[0109] In one embodiment, before spirally rolling the composite steel strip 20 in S400, the step further includes: shielding the heated area of ​​the web with an inert gas. Carbon dioxide, 99.99% high-purity argon, or nitrogen is simultaneously introduced into the heated area as a shielding medium. A laminar protective air curtain of 0.5-1.2 m³ / min is formed through a surrounding air curtain nozzle to control the oxygen content below 50 ppm, effectively suppressing the formation of oxides such as Fe₃O₄ and preventing material strength loss due to intergranular oxidation.

[0110] In one embodiment, after spirally coiling the composite steel strip 20 in step S400, the following step further comprises: cooling the web after coiling. The cooling area corresponds to the heating area. Because the composite steel strip 20 is a long structure, cooling and heating can be performed simultaneously at different locations on the composite steel strip 20. Cooling is performed by a cooling element 34, which is located downstream of the heating element 36 along the coiling direction of the composite steel strip 20. This real-time cooling prevents heat transfer to the inner tube (first steel strip 201), which could cause deformation after softening.

[0111] In one embodiment, after the step of spirally rolling the composite steel strip 20 in S400, the process further includes: shaping the web or composite steel strip 20 before cooling, so that the web has a uniform height, or so that both sides of the web are straight (i.e., both sides are perpendicular to the first steel strip 201). Specifically, the shaping step includes shaping both sides and ends of the web in the composite steel strip 20, and also shaping the inner side surface of the first steel strip 201 in the composite steel strip 20.

[0112] Thus, the above manufacturing method has the following technical effects:

[0113] Rolling of composite steel plates is easy to achieve: the web can provide space for local elastic deformation when the composite steel strip 20 is bent, allowing the outer and inner layers of the steel plate to extend differentially without wrinkling or breaking. The groove gap absorbs about 30% of the bending stress, significantly reducing the plastic tensile damage to the base material. The composite steel plate adopts a gradient structure design. When rolling, the outer layer bears the main tensile stress, and the inner layer releases residual stress through plastic deformation to avoid overall rebound deformation. The uniform thickness and straightness of the composite steel plate are highly compatible with existing pipe rolling equipment. The laser positioning system can achieve precise control of the spiral winding angle (±0.5° error), and the rolling efficiency is increased to 2.3 times that of the traditional process. Reduced equipment power: The structure based on the web is lighter, the concrete filling process is more convenient, and the power required for external equipment such as pouring and rolling is also smaller. In addition, the web shaping device can make the height of the web consistent after rolling, and the end surface of the top of the web is flat, which can be used for subsequent size coordination with the outer tube steel strip; web shaping can ensure the appearance and dimensional quality of the web in the height direction, ensure the verticality of the web and the inner tube surface, and ensure the uniformity of the size of the web spacing of each circle, which is conducive to the subsequent dimensional coordination with the outer tube steel strip in the axial direction; gas protection can prevent and reduce oxidation of the steel plate surface in high heat; cooling can reduce the temperature of the steel plate to prevent oxidation or deformation.

[0114] like Figure 7-10 As shown, the present application also provides a manufacturing device 30 for a double-wall spiral welded pipe with a hole in the web, which adopts the manufacturing method of the double-wall spiral welded pipe with a hole in the web as described above, and the manufacturing device 30 includes: a rolling component, including a rolling pressure roller 31 and a rolling wheel shaft 32, the rolling pressure roller 31 and the rolling wheel shaft 32 are respectively arranged above and below the composite steel strip 20, for rolling the composite steel strip 20; and a plurality of heating elements 36 are arranged at intervals, arranged upstream of the rolling component, and arranged to extend to the rolling wheel shaft 32, covering at least part of the web of the composite steel strip 20, for example, half of the height of the web.

[0115] Specifically, heating elements 36 are spaced apart and surround the outer side of the web, covering half the web's height. Heating elements 36 are comprised of induction heating coils and wires connecting the induction heating coils. At least two heating elements 36 are provided, and the two heating elements 36 can be spaced apart in the direction of coiling of the composite steel strip 20 to provide continuous heating as coiling proceeds.

[0116] In one embodiment, the rolling assembly further includes a support roller 322 and a bearing 321. The support roller 322 is disposed between adjacent webs, and the bearing 321 is disposed between the support roller 322 and the rolling wheel shaft 32. Specifically, since the outer side of the composite steel strip 20 corresponds to one side of the web, at least two support rollers 322 are provided. Adjacent support rollers 322 are disposed between adjacent webs, such that the circumferential surface of the support roller 322 abuts between the first steel strip and the bearing 321, and the axial ends of the support roller 322 abut against two adjacent webs. The angle of the support roller 322 is adjustable to match the feed angle of the composite steel strip 20 and to adapt to the angle of the gradually rolled spiral web 300. The diameter of the support roller 322 is greater than or equal to the height of the web, allowing the bearing 321 to span at least two webs.

[0117] In one embodiment, Figure 10 As shown, a shaping assembly 33 is provided downstream of the curling assembly. This shaping assembly 33 includes a correction clamping wheel 331 and a web height-setting pressing wheel 332. At least two correction clamping wheels 331 are provided, one on each side of the web. The outer surfaces of the web height-setting pressing wheels 332 abut the end of the web facing away from the first steel strip. The web height-setting pressing wheels 332 are fixed at a fixed height, pressing the heated and curled web to a uniform height after passing through the web height-setting pressing wheels 332. The spacing between the two correction clamping wheels 331 is fixed to prevent and correct web bending or skewing.

[0118] In one embodiment, a cooling element 34 is further provided downstream of the shaping assembly 33. The cooling element 34 is located outside the rolled composite steel strip 20 and is a wet cooling roller. Specifically, the cooling roller is a roller structure having a flexible, water-absorbing material on its surface. Preferably, the cooling roller is a rag roller that can remain wet and roll along the inner wall.

[0119] In one embodiment, the manufacturing device 30 includes a blower (not shown) located downstream of the cooling element 34. When the cooling element is wet, the blower is used to dry the composite steel strip 20. It is understood that when the cooling element is air-cooled, the blower can be the cooling element itself.

[0120] In one embodiment, the manufacturing device 30 further includes a feed roller 35, which is located at the same level as the winding wheel shaft 32. The rolling pressure roller 31 is located horizontally at the midpoint between the feed roller 35 and the winding wheel shaft 32. Similar to the winding wheel shaft 32, the feed roller 35 is also provided with a support roller 322 and a bearing 321.

[0121] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0122] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A double-wall spiral welded pipe with a web having holes, characterized in that: The double-wall spiral welded pipe comprises: The outer tube is made by spirally rolling the second steel strip, and the outer tube is cylindrical in shape as a whole; An inner tube is sleeved inside the outer tube and is made of a first steel strip spirally rolled into a circle. The inner tube is cylindrical in shape and can be sleeved with the outer tube to form a receiving cavity between the sleeved inner tube and the outer tube; and A spiral web is provided in the accommodating cavity. The spiral web is spiral-shaped, and the inner periphery of the spiral web is connected to the outer surface of the inner tube, and the outer periphery of the spiral web is connected to the inner surface of the outer tube. The spiral web divides the accommodating cavity into spiral cavities; a plurality of through holes are provided on the spiral web, and the through holes are used to connect the air of adjacent spiral cavities.

2. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The through hole is located on the spiral web close to the outer tube; And / or, the plurality of through holes are arranged at intervals, and the spacing between adjacent through holes is greater than the diameter of the through holes; And / or, the diameter of the through hole is less than half the height of the spiral web.

3. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The through hole is arranged on one side of the root of the spiral web.

4. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The spiral web is provided with an opening, the opening is directed in a radial direction to connect the through hole with the outside, and the opening is located on a side of the spiral web facing the outer tube; And / or, the opening is in a straight line shape, a V shape, an inverted Ω shape and / or a semicircular shape; And / or, the spiral web is provided with a slit, the slit connects the through hole with the outside in a radial direction, and the slit is located on a side of the spiral web facing the outer tube.

5. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The double-wall spiral welded pipe further comprises a concrete layer, which is poured into the spiral cavity formed between the outer pipe and the inner pipe.

6. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The plurality of through holes are arranged in a row along a circumferential direction parallel to the inner tube wall; or, the plurality of through holes are arranged in at least two rows along a circumferential direction parallel to the inner tube wall, and the through holes in two adjacent rows are staggered in a direction parallel to the inner tube wall.

7. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The spiral web is formed by rolling a straight web, and the height of the web before rolling is higher than the height of the spiral web.

8. The double-wall spiral welded pipe with web holes according to claim 1, characterized in that: The thickness of the spiral web at one end facing the outer tube is greater than the thickness of the middle portion of the spiral web.

9. A method for manufacturing a double-wall spiral welded pipe with a web having holes, characterized in that: The manufacturing method comprises the steps of: Unwinding a narrow steel strip and punching holes in the narrow steel strip to make a web with through holes; unwinding the first steel strip, placing the web on the first steel strip, and welding the first steel strip and the narrow steel strip to form a composite steel strip; Turning over the composite steel strip, spirally rolling the composite steel strip, and welding the spiral butt weld formed after the composite steel strip is rolled to form a tube blank; A second steel strip is released from under the tube blank and fitted onto the tube blank. As the tube blank is spirally rolled, a welding gun is inserted into the interlayer between the tube blank and the second steel strip to weld the web and the second steel strip together, and then weld the spiral butt weld of the second steel strip to make a double-wall spiral welded pipe.

10. A method for manufacturing a double-wall spiral welded pipe with web holes, characterized in that: The manufacturing method comprises the steps of: Unwinding a narrow steel strip and punching holes in the narrow steel strip to make a web with through holes; unwinding the first steel strip, placing the web on the first steel strip, and welding the first steel strip and the narrow steel strip to form a composite steel strip; Turning over the composite steel strip, and simultaneously heating the web when the composite steel strip is rolled; spirally rolling the composite steel strip, and welding the spiral butt weld formed after the composite steel strip is rolled to form a tube blank; A second steel strip is released from under the tube blank and fitted onto the tube blank. As the tube blank is spirally rolled, a welding gun is inserted into the interlayer between the tube blank and the second steel strip to weld the web and the second steel strip together, and then weld the spiral butt weld of the second steel strip to make a double-wall spiral welded pipe.

11. The method for manufacturing a double-wall spiral welded pipe with web holes according to claim 10, characterized in that: The heating area avoids the root of the web.

12. The method for manufacturing a double-wall spiral welded pipe with web holes according to claim 10, characterized in that: The heating method is induction heating; and / or the heating temperature is 900-1200°C.

13. The method for manufacturing a double-wall spiral welded pipe with web holes according to claim 10, characterized in that: The step of heating the web further includes: protecting the heated area of ​​the web with an inert gas.

14. The method for manufacturing a double-wall spiral welded pipe with web holes according to claim 10, characterized in that: After the step of spirally rolling the composite steel strip, the method further includes: cooling the web after rolling.

15. The method for manufacturing a double-wall spiral welded pipe with web holes according to claim 14, characterized in that: After the step of spirally rolling the composite steel strip, the method further includes: before cooling, shaping the web or the composite steel strip so that the height of the web is uniform or both sides of the web are straight.

16. A manufacturing device for a double-wall spiral welded pipe with holes in the web, characterized in that: The method for manufacturing a double-wall spiral welded pipe with web holes according to any one of claims 9 to 15 is adopted, wherein the manufacturing device comprises: A rolling assembly, comprising a rolling pressure roller and a rolling axle, wherein the rolling pressure roller and the rolling axle are respectively arranged above and below the composite steel strip, and are used to roll the composite steel strip; The heating element is arranged upstream of the rolling assembly and is arranged to extend to the rolling wheel shaft.

17. The manufacturing device of the double-wall spiral welded pipe with web holes according to claim 16, characterized in that: The rolling assembly further includes a supporting wheel and a bearing. The supporting wheel is arranged between adjacent webs, and the bearing is arranged between the supporting wheel and the rolling wheel shaft. The supporting wheel can be adjusted in angle to match the feeding angle of the composite steel strip.

18. The manufacturing device for a double-wall spiral welded pipe with web holes according to claim 16, characterized in that: A shaping assembly is also provided downstream of the rolling assembly, and the shaping assembly includes a correction clamping wheel and a shaping pressure wheel. There are at least two correction clamping wheels, and the correction clamping wheels are provided on both sides of the web. The outer surface of the height shaping pressure wheel of the web abuts against the end of the web away from the first steel belt.

19. The manufacturing device for a double-wall spiral welded pipe with web holes according to claim 18, characterized in that: A cooling member is further provided downstream of the shaping assembly. The cooling member is provided on the outer side of the rolled composite steel strip and is a cooling roller in a wet state.

20. The manufacturing device for a double-wall spiral welded pipe with web holes according to claim 18, characterized in that: The manufacturing device comprises a wind tube located downstream of the cooling member, and the wind tube is used for drying the composite steel strip.

Images