Double-layer spiral corrugated steel pipe and manufacturing method thereof

Abstract

The invention relates to a double-layer spiral corrugated steel pipe and a manufacturing method thereof. Wherein the double-layer spiral corrugated steel pipe is formed by rolling a composite corrugated steel strip and comprises an inner pipe and an outer pipe, and the inner pipe is a straight pipe; the composite corrugated steel belt comprises a corrugated layer and an inner wall layer, the corrugated layer is connected with the inner wall layer in a welded mode, the corrugated layer is used for forming the outer pipe wall of the spiral corrugated steel pipe, and the inner wall layer is used for forming the inner pipe wall of the spiral corrugated steel pipe. According to the double-layer spiral corrugated steel pipe and the manufacturing method thereof, the internal flow resistance of the spiral corrugated steel pipe can be reduced, the adaptability is high, the production complexity can be reduced, and the production efficiency can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of fluid pipelines, and in particular to a double-layer spiral corrugated steel pipe and a manufacturing method thereof. Background Art

[0002] The water pipes in the water supply and drainage system are key components to ensure the transportation and discharge of water resources. They can be divided into water supply pipes and drainage pipes according to their different uses. There are many types, such as concrete water pipes, cast iron water pipes and PVC water pipes. Pipes are often buried in the soil and need to have sufficient rigidity to ensure that they can withstand the pressure of the surrounding soil, traffic loads, changes in the surrounding environment and other factors to avoid deformation or rupture of the pipes. Ring stiffness is one of the main indicators to characterize the stiffness of the pipeline. The wall of the spiral corrugated steel pipe has a spiral corrugated structure. The corrugated structure can disperse pressure and load when subjected to force. Therefore, the spiral corrugated steel pipe has a higher ring stiffness and can meet the stiffness requirements of underground water pipes.

[0003] In the prior art, spiral corrugated steel pipes usually have corrugated structures on both the inner and outer walls, which have large water flow resistance and are not suitable for water supply. Therefore, steel pipes with flat inner wall pipes and corrugated outer pipes are more suitable for water supply pipelines, but such steel pipes usually need to be equipped with reinforcing ribs and other structures to improve their structural strength, and the production and processing process is complicated and inefficient. Summary of the invention

[0004] Based on this, it is necessary to provide a double-layer spiral corrugated steel pipe and a manufacturing method thereof that can improve the processing efficiency while ensuring the structural strength of the steel pipe in order to address the above problems.

[0005] In a first aspect, a double-layer spiral corrugated steel pipe is provided, which is formed by rolling a composite corrugated steel strip, and includes an inner tube and an outer tube, wherein the inner tube is a spirally welded straight tube; the composite corrugated steel strip includes a corrugated layer and an inner wall layer, wherein the corrugated layer and the inner wall layer are welded and connected, the corrugated layer is used to form the outer tube wall of the spiral corrugated steel pipe, and the inner wall layer is used to form the inner tube wall of the spiral corrugated steel pipe.

[0006] In one embodiment, the corrugated layer includes a first steel strip, which is a corrugated steel strip. The first steel strip is welded to form a first spiral weld after spiral rolling. The inner wall layer includes a second steel strip, which is a flat steel strip. The second steel strip is welded to form a second spiral weld after spiral rolling. The positions of the first spiral weld and the second spiral weld do not overlap. During welding, the position of the first weld is closer to the extension direction of the tube body than the position of the second weld.

[0007] In one embodiment, vertical edges are provided at both ends of the first steel strip in the width direction, and the vertical edges are used to be welded to form a first spiral weld, and the vertical edges at both ends of the first steel strip have the same bending direction.

[0008] In one embodiment, the free end of the vertical edge faces the outside of the spiral corrugated steel tube.

[0009] In one embodiment, shear nails are arranged above and / or below the second steel belt.

[0010] In one of the embodiments, steel bars are provided between the corrugated layer and the inner wall layer.

[0011] In one embodiment, the first steel strip and the second steel strip have the same width, and the first steel strip and the second steel strip are staggered in the width direction.

[0012] In one embodiment, the lateral end of the second steel strip is welded to the crest or trough of the first steel strip.

[0013] In one embodiment, the wave crests or wave troughs of the first steel strip have straight sections.

[0014] In one embodiment, the gap between the outer wall of the inner tube and the inner wall of the outer tube is filled with concrete.

[0015] In a second aspect, a method for processing a spiral corrugated steel pipe is provided, wherein the method is used to process the spiral corrugated steel pipe as described in the first aspect or any embodiment of the first aspect, comprising the following steps:

[0016] Prepare a corrugated steel strip and a flat steel strip, bend the corrugated steel strip, and form vertical edges at both ends of the corrugated steel strip in the width direction;

[0017] Laminating the corrugated steel strip and the flat steel strip so that one side edge of the flat steel strip along the width direction overlaps with the crest or trough of the corrugated steel strip, and welding the contact points of the corrugated steel strip and the flat steel strip to obtain a composite corrugated steel strip;

[0018] The composite corrugated steel strip is spirally rolled, the spiral butt weld of the flat steel strip is welded inside the pipe body, and the spiral butt weld of the corrugated steel strip is welded outside the pipe body to obtain a double-layer spiral corrugated steel pipe.

[0019] The above-mentioned double-layer spiral corrugated steel pipe and its manufacturing method, the outer layer of the corrugated steel pipe has good bearing capacity and ring stiffness, can effectively resist external pressure and ground load, the strengthening effect of the corrugated structure can improve the overall pressure resistance of the pipeline, and is suitable for environments that need to withstand large external pressure or loads. The inner pipe adopts a straight pipe, and the inner wall layer is reinforced by the inner wall layer of the corrugated steel belt. While ensuring the stability of the pipeline structure, it can also better resist the water pressure changes of the internal flow and reduce the flow resistance. It is suitable for water supply. The double-layer spiral corrugated steel pipe and its manufacturing method provided by the present invention can reduce the internal flow resistance of the spiral corrugated steel pipe, has strong adaptability, and can reduce production complexity and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of the structure of a double-layer spiral corrugated steel pipe provided in one embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a first steel belt of a double-layer spiral corrugated steel pipe provided in one embodiment of the present application;

[0023] Figure 3 A schematic diagram of the connection relationship between the first steel belt and the second steel belt of the double-layer spiral corrugated steel pipe provided in one embodiment of the present application;

[0024] Figure 4 A schematic diagram of a steel pipe winding step in a method for manufacturing a double-layer spiral corrugated steel pipe provided in an embodiment of the present application;

[0025] Figure 5 A schematic diagram of the structure of a winding device used in a method for manufacturing a double-layer spiral corrugated steel pipe provided in an embodiment of the present application;

[0026] Figure 6 A schematic diagram of the pipe wall structure of a double-layer spiral corrugated steel pipe after winding is completed provided in one embodiment of the present application.

[0027] In order to make the above and other objects, features, advantages and embodiments of the present invention more clearly understood, the attached symbols are explained as follows:

[0028] 10. Pipe body; 100. Composite corrugated steel strip; 200. Inner wall layer; 210. Second steel strip; 220. First spiral weld; 300. Corrugated layer; 310. First steel strip; 311. Vertical edge; 320. Second spiral weld; 400. Gap; 500. End sealing ring plate; 610. First roll; 620. Second roll; 630. Third roll. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0030] In the description of the present invention, it should be understood that 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" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that when 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 a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0035] Figure 1 A schematic diagram of the structure of a double-layer spiral corrugated steel pipe provided in one embodiment of the present application; Figure 2 A schematic structural diagram of a first steel belt 310 of a double-layer spiral corrugated steel pipe provided in an embodiment of the present application; Figure 3 A schematic diagram of the connection relationship between the first steel belt 310 and the second steel belt 210 of the double-layer spiral corrugated steel pipe provided in an embodiment of the present application; see Figures 1 to 3 A double-layer spiral corrugated steel pipe provided by an embodiment of the present invention is formed by rolling a composite corrugated steel strip 100, including an inner tube and an outer tube, and the inner tube is a spirally welded straight tube; the composite corrugated steel strip 100 includes a corrugated layer 300 and an inner wall layer 200, wherein the corrugated layer 300 and the inner wall layer 200 are welded and connected, the corrugated layer 300 is used to form the outer tube wall of the spiral corrugated steel pipe, and the inner wall layer 200 is used to form the inner tube wall of the spiral corrugated steel pipe.

[0036] Among them, the inner pipe refers to the inner layer of the steel pipe, which is used for the transportation of fluids, and the outer pipe refers to the structure arranged on the outer layer of the inner pipe, which is used to improve the overall structural performance of the steel pipe. The composite corrugated steel strip 100 refers to a steel strip with a corrugated structure formed by combining two or more different steel strips together through a specific process. The steel strip materials used in the corrugated layer 300 and the inner wall layer 200 can be the same or different. The steel strip can be a galvanized steel strip, a stainless steel strip, a carbon steel strip, a galvanized steel strip or a coated steel strip, etc. The corrugated layer 300 is mainly used to form the external corrugated structure of the pipeline, enhance the ring stiffness and external force resistance of the pipeline, and can use a high-strength steel strip such as a galvanized steel strip, a stainless steel strip or a carbon steel strip. The inner wall layer 200 is used to form the inner wall of the pipeline, directly contacting the fluid, and can use a steel strip with good corrosion resistance such as a galvanized steel strip, a coated steel strip, a PVC coated steel strip or a PE coated steel strip. The outer tube of the double-layer spiral corrugated steel pipe has a corrugated structure, which can disperse pressure and load, making it more difficult for the pipe to deform under external pressure, improving the overall ring stiffness of the pipeline, and enabling it to adapt to environments with high external pressure or variable loads. The inner tube is a straight tube, which can reduce the flow resistance of the fluid in the pipeline, so that the steel pipe can be used as a water supply pipeline with high water pressure and fast flow rate. The spiral winding and rolling molding is adopted, so that the pipe can disperse the load in multiple directions, further improving its ring stiffness. The use of composite corrugated steel strip 100 to roll into a steel pipe can effectively simplify the production process and improve production efficiency. The welding connection of the corrugated layer 300 and the inner wall layer 200 can firmly combine the inner and outer layers, ensure the overall firmness and sealing of the pipeline, avoid problems such as unstable connection in the traditional two-layer structure, and extend the service life of the pipeline.

[0037] The above-mentioned double-layer spiral corrugated steel pipe and its manufacturing method, the outer corrugated steel pipe has good bearing capacity and ring stiffness, can effectively resist external pressure and ground load, the reinforcement effect of the corrugated structure can improve the overall pressure resistance of the pipeline, and is suitable for environments that need to withstand large external pressure or loads. The inner pipe adopts a straight pipe, and the inner wall layer 200 is reinforced by the inner wall layer 200 of the corrugated steel belt. While ensuring the stability of the pipeline structure, it can also better resist the water pressure changes of the internal flow and reduce the flow resistance. It is suitable for water supply. The double-layer spiral corrugated steel pipe and its manufacturing method provided by the present invention can reduce the internal flow resistance of the spiral corrugated steel pipe, has strong adaptability, and can reduce production complexity and improve production efficiency.

[0038] In an exemplary embodiment, the corrugated layer 300 includes a first steel strip 310, which is a corrugated steel strip. The first steel strip 310 is welded to form a first spiral weld 220 after spiral rolling. The inner wall layer 200 includes a second steel strip 210, which is a flat steel strip. The second steel strip 210 is welded to form a second spiral weld 320 after spiral rolling. The positions of the first spiral weld 220 and the second spiral weld 320 do not overlap. During welding, the position of the first weld is closer to the extension direction of the tube body than the position of the second weld. Among them, the first steel strip 310 can be rolled from a flat steel strip, and the first steel strip 310 and the second steel strip 210 can be welded and connected to obtain the composite corrugated steel strip 100. After the composite corrugated steel strip 100 is rolled into a circle, the spiral welds of the first steel strip 310 and the second steel strip 210 are respectively welded to form a first spiral weld 220 and a second spiral weld 320. The positions of the first spiral weld 220 and the second spiral weld 320 do not overlap, which means that the first steel strip 310 and the second steel strip 210 are staggered by a certain size in the width direction. After the winding is completed, the spiral welds of the two are also staggered. Since the weld is the weakest part of the pipeline and is prone to become a stress concentration point, by staggering the welds of the inner and outer layers, stress concentration on a certain weld can be effectively avoided, thereby reducing the possibility of stress concentration at the weld. Staggered welds allow the inner and outer layers of the pipeline to support each other to form a more balanced load-bearing structure. Compared with the structure with aligned welds, staggered welds can improve the bonding strength of the inner and outer layers of the pipeline, more effectively disperse external stresses such as tension and pressure, and also help to balance the internal stress generated during welding, reduce deformation and distortion of the pipeline, and improve the tensile strength and durability of the pipeline.

[0039] In an exemplary embodiment, the first steel strip 310 is provided with vertical edges 311 at both ends in the width direction, and the vertical edges 311 are used to be welded to form the first spiral weld 220. The vertical edges 311 at both ends of the first steel strip 310 extend in the same direction. The vertical edges 311 can be formed by bending the two ends in the width direction of the first steel strip 310. The vertical edges 311 are provided at the threaded connection of the corrugated steel strip to increase the contact area and make the welding connection more reliable. When the steel strip is wound into a steel pipe, the two vertical edges 311 abut against each other, which can improve the structural stability and reduce the occurrence of deformation. The vertical edge 311 structure can also play a role in improving the structural strength after filling with concrete.

[0040] In an exemplary embodiment, the free end of the vertical edge 311 faces the outside of the spiral corrugated steel pipe. When the free end is located outside the spiral corrugated steel pipe, it is easier to weld, and the contact part between the first steel strip 310 and the inner straight pipe can be the crest or trough of the corrugation, so that the contact part between the inner and outer layers of the pipe wall remains consistent.

[0041] In an exemplary embodiment, when the length of the vertical edge 311 is equal to the wave height, the end of the vertical edge 311 is welded to the second steel strip 210. Wave height refers to the vertical distance between the crest and the trough in the wave structure. When the length of the vertical edge 311 is less than or equal to the wave height, the structure of the first steel plate and the second steel plate can be made tighter, the structural strength can be improved and the processing is easy. When the length of the vertical edge 311 is equal to the wave height, the vertical edge 311 can abut against the flat steel strip to provide additional support for the corrugated steel strip. The end of the vertical edge 311 is welded to the second steel strip 210 to fix the edge of the corrugated steel strip and reduce deformation during the winding process.

[0042] In an exemplary embodiment, the first steel strip 310 and the second steel strip 210 have the same width, and the first steel strip 310 and the second steel strip 210 are staggered in the width direction. The first steel strip 310 and the second steel strip 210 are staggered in the width direction, so that the spiral welds can be staggered, so as to avoid the overlap of the welds of the two layers of steel strips and affect the structural strength at the welds, and reduce the influence of the other weld when one weld fails, thereby improving the reliability of the structure.

[0043] In an exemplary embodiment, the end of the second steel strip 210 is welded to the crest or trough of the first steel strip 310. Connecting the end of the second steel strip 210 to the crest or trough of the first steel strip 310 can ensure that one end of the second steel strip 210 is not suspended, thereby improving the stability of the structure.

[0044] In an exemplary embodiment, the crest or trough of the first steel strip 310 has a straight section. The crest and trough may be arc-shaped or have a straight section, and the straight section has a larger contact area with the second steel strip 210, which can improve stability and facilitate welding.

[0045] In an exemplary embodiment, the gap between the outer wall of the inner tube and the inner wall of the outer tube is filled with concrete.

[0046] In an exemplary embodiment, shear spikes are provided above and / or below the second steel strip.

[0047] In an exemplary embodiment, steel bars are provided between the corrugated layer and the inner wall layer.

[0048] like Figure 1 As shown, the gap between the two forms a spiral cavity. Filling the cavity with concrete can effectively disperse the external pressure and reduce pipe deformation. Filling concrete between the inner and outer layers of the pipe can improve the overall stiffness and seismic resistance of the pipe.

[0049] In an exemplary embodiment, a method for processing a spiral corrugated steel pipe is provided. The method is used to process the spiral corrugated steel pipe as in the first aspect or any embodiment of the first aspect, and comprises the following steps:

[0050] Prepare a corrugated steel strip and a flat steel strip, bend the corrugated steel strip, and form vertical edges 311 at both ends of the corrugated steel strip in the width direction;

[0051] Laminating the corrugated steel strip and the flat steel strip so that one side edge of the flat steel strip along the width direction overlaps with the crest or trough of the corrugated steel strip, and welding the contact points of the corrugated steel strip and the flat steel strip to obtain a composite corrugated steel strip 100;

[0052] The composite corrugated steel strip 100 is spirally rolled, a spiral butt weld of a flat steel strip is welded inside the pipe body 10, and a spiral butt weld of a corrugated steel strip is welded outside the pipe body 10 to obtain a double-layer spiral corrugated steel pipe.

[0053] In an exemplary embodiment, the method for processing a spiral corrugated steel pipe comprises the following steps:

[0054] The first steel strip 310 is unwound by the unwinding machine, and the first steel strip 310 is rolled into a corrugated steel strip, and vertical edges 311 are processed on both sides of the corrugated steel strip. The direction of the vertical edges 311 can be upward or downward. However, the directions of the vertical edges 311 on both sides are consistent for easy welding. The height of the vertical edges 311 is not higher than the wave height of the corrugation.

[0055] Then, the second steel strip 210 is unwound by the unwinding machine, and the width of the second steel strip 210 is equal to that of the first steel strip 310 .

[0056] The second steel strip 210 is pressed against the bottom of the corrugated steel strip and staggered in the width direction. After staggering, one side edge of the second steel strip 210 is placed on the top of one of the corrugations on the corrugated steel strip. Then, the contact line (point) between the corrugated steel strip and the second steel strip 210 is welded to weld the two layers of steel plates together. The weld is on one side of the corrugated steel strip.

[0057] After the above process is completed, the corrugated steel strip and the second steel strip 210 form a composite steel strip, and then the composite steel strip is flipped 180 degrees so that the corrugated steel strip faces downward, and then the flipped composite steel strip is delivered to the spiral rolling forming machine by the delivery mechanism for spiral rolling.

[0058] In the above process, a spiral butt weld of the first steel strip 310 is welded inside the tube body 10 .

[0059] A spiral butt weld is formed between the corrugated steel strips on the outside of the pipe body 10. In the above process, the width of the corrugation with the vertical edge 311 is half of the width of the middle standard corrugation. After the butt welding of the two corrugations with the vertical edge 311 is completed, an integral standard corrugation is formed.

[0060] In an exemplary embodiment, the height of the standing edge 311 of the corrugation with the standing edge 311 is consistent with the standard corrugation height. At this time, the top of the standing edge 311 is welded to the first steel strip 310 .

[0061] In an exemplary embodiment, the wave top welded to the first steel strip 310 may not be an arc, but may have a short flat section.

[0062] In an exemplary embodiment, shear nails are arranged on and / or below the first steel strip 310. Shear nails are fasteners used only for connecting steel structures and concrete structures, and can be cylindrical or conical, and have grooves or welding surfaces. Shear nails can be connected to the first steel strip 310 by welding or mechanical connection, which can improve the shear connection strength of the structure.

[0063] In an exemplary embodiment, the spiral welds between the corrugated steel strips move forward in the direction of forming the pipe body 10 and are staggered with the spiral butt welds of the first steel strip 310 .

[0064] In an exemplary embodiment, the butt weld of the first steel strip 310 is at the top of the corrugation and is welded to the corrugation as a whole.

[0065] In an exemplary embodiment, after the pipe body 10 is formed and cut into a pipe body 10 of a required length, concrete is filled into the interlayer between the two closed layers, and end sealing ring plates are provided at both ends of the pipe body 10.

[0066] The above double-layer spiral corrugated steel pipe and its manufacturing method have the following beneficial effects: the quality of the weld between the corrugated steel pipe and the straight steel pipe is easy to control. After the second steel strip 210 and the corrugated steel strip form a composite steel strip, the forming angle of the steel strip and the tube body 10 can be made consistent, and the equipment is easy to implement. The setting of the vertical edge 311 can make it difficult for the edge of the composite steel strip to produce a ruffle (wavy edge) after rolling, while ensuring the quality of the tube body 10, and reducing the welding deformation when the two vertical edges 311 are butt-welded. The spiral butt welds of the corrugated steel pipe and the straight steel pipe are staggered to avoid stress concentration in the weld of the tube body 10. The staggered weld setting, especially the staggered direction of the corrugated plate is moved forward to the forming direction of the tube body 10, can simultaneously and smoothly realize the overlap and butt joint of the two layers closed under the No. 2 roller. The butt welds between the first steel strips 310 are set at the top of the corrugation, and the wave top at this time is the plane reference for the butt joint between the first steel strips 310. At the same time, it also acts as a welding pad, which ensures the flatness of the first steel strip 310 and strengthens the strength of the butt weld. After the two layers of pipe wall are filled with concrete, a steel and concrete composite structure pipe wall can be formed, and the ability of the pipe body 10 to withstand internal and external pressures is enhanced. After the first steel strip 310 is welded to the corrugated steel strip as a whole, when it is rolled, the first steel strip 310 has a limiting effect on the deformation of the corrugated steel strip.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0068] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A double-layer spiral corrugated steel pipe, characterized in that: The double-layer spiral corrugated steel pipe is formed by rolling a composite corrugated steel strip, and includes an inner tube and an outer tube, wherein the inner tube is a spirally welded straight tube; the composite corrugated steel strip includes a corrugated layer and an inner wall layer, wherein the corrugated layer and the inner wall layer are welded and connected, the corrugated layer is used to form the outer tube wall of the spiral corrugated steel pipe, and the inner wall layer is used to form the inner tube wall of the spiral corrugated steel pipe.

2. The spiral corrugated steel pipe according to claim 1, characterized in that: The corrugated layer includes a first steel strip, which is a corrugated steel strip. The first steel strip is welded to form a first spiral weld after spiral rolling. The inner wall layer includes a second steel strip, which is a flat steel strip. The second steel strip is welded to form a second spiral weld after spiral rolling. The positions of the first spiral weld and the second spiral weld do not overlap. During welding, the position of the first weld is closer to the extension direction of the tube body than the position of the second weld.

3. The spiral corrugated steel pipe according to claim 2, characterized in that: The first steel strip is provided with vertical edges at both ends along the width direction, and the vertical edges are used to be welded to form a first spiral weld. The vertical edges at both ends of the first steel strip have the same bending direction.

4. The spiral corrugated steel pipe according to claim 3, characterized in that: The free end of the vertical edge faces the outer side of the spiral corrugated steel pipe.

5. The spiral corrugated steel pipe according to claim 4, characterized in that: Shear nails are arranged above and / or below the second steel belt.

6. The spiral corrugated steel pipe according to claim 1, characterized in that: Steel bars are arranged between the corrugated layer and the inner wall layer.

7. The spiral corrugated steel pipe according to claim 2, characterized in that: The first steel strip and the second steel strip have the same width, and the first steel strip and the second steel strip are staggered in the width direction.

8. The spiral corrugated steel pipe according to claim 2, characterized in that: The lateral ends of the second steel strip are welded to the wave crests or wave troughs of the first steel strip.

9. The spiral corrugated steel pipe according to claim 2, characterized in that: The wave crests or wave troughs of the first steel strip have straight sections.

10. The spiral corrugated steel pipe according to claim 1, characterized in that: The gap between the outer wall of the inner tube and the inner wall of the outer tube is filled with concrete.

11. A method for processing a spiral corrugated steel pipe, characterized in that: The method is used to process the spiral corrugated steel pipe according to any one of claims 1 to 10, comprising the following steps: Prepare a corrugated steel strip and a flat steel strip, bend the corrugated steel strip, and form vertical edges at both ends of the corrugated steel strip in the width direction; Laminating the corrugated steel strip and the flat steel strip so that one side edge of the flat steel strip along the width direction overlaps with the crest or trough of the corrugated steel strip, and welding the contact points of the corrugated steel strip and the flat steel strip to obtain a composite corrugated steel strip; The composite corrugated steel strip is spirally rolled, the spiral butt weld of the flat steel strip is welded inside the pipe body, and the spiral butt weld of the corrugated steel strip is welded outside the pipe body to obtain a double-layer spiral corrugated steel pipe.

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