A drag-reducing roller for cable laying

Abstract

The application relates to a cable laying drag-reducing roller, which comprises a steel ring and a rolling assembly; the steel ring is sleeved and fixed on the outer surface of a cable, and the inner diameter of the steel ring matches the outer diameter of the cable; the rolling assembly is uniformly installed on the outer surface of the steel ring in the circumferential direction and comprises a support frame and a drum-shaped ball, the support frame is fixed on the steel ring, the drum-shaped ball is installed on the support frame, and the curvature of the generatrix of the drum-shaped ball matches the curvature of the inner wall of a laying pipeline. The application has the advantages that two steel sheets connected through a hinge are buckled on the outer surface of the cable, installation is convenient, the drum-shaped ball is adopted in the rolling assembly, the curvature of the generatrix is the same as the curvature of the pipeline, the contact area of the rolling assembly and the pipeline is increased, the abrasion of the pipeline wall is reduced, and the service life of the drag-reducing roller is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of cable laying technology, and in particular to a drag-reducing roller for cable laying. Background Technology

[0002] Submarine cable landing projects for offshore wind farms are a crucial link in the grid connection and transmission of offshore wind power. With the rapid growth of global offshore wind power installed capacity, related technologies are developing rapidly. In submarine cable landing projects, it is common practice to protect the cable through pre-laid steel pipes (such as directional drilling casings, jacking pipes, or buried pipes), while drag reduction measures (technical means to reduce frictional resistance) are crucial in this process.

[0003] In traditional offshore cable laying, the frictional resistance between the cable and the inner wall of the duct is significant. This not only increases the load on the traction equipment but can also lead to problems such as wear on the cable's outer sheath and damage to the insulation layer. In severe cases, it can even affect the cable's service life and power transmission performance. Drag-reducing rollers, by incorporating a rolling wheel structure on the cable's outer surface or the duct's inner wall, convert the sliding friction between the cable and the duct into rolling friction, thereby significantly reducing the coefficient of friction and laying resistance.

[0004] In practical engineering, the structural form, material selection, and arrangement of drag-reducing rollers must be comprehensively designed based on parameters such as cable type and specifications, duct inner diameter, curvature of the laying path, and laying tension. For large-diameter submarine cables and long-distance, complex duct laying, it is usually necessary to design roller structures with high load-bearing capacity and wear resistance, and to rationally plan the spacing and arrangement of the rollers to ensure that the weight of the submarine cable is evenly distributed throughout the laying process, avoiding local stress concentration. At the same time, the ease of installation and maintenance of drag-reducing rollers is also an important factor to consider in engineering applications, facilitating rapid installation and replacement on-site and improving construction efficiency.

[0005] Chinese patent CN104167695A discloses a drag-reducing device for laying submarine cables. It involves fixing an upper and lower cover to the cable with bolts and installing drag-reducing mechanisms at regular intervals on the cable to reduce drag during submarine cable laying. However, this application uses bearings to achieve rolling friction, resulting in a small contact area between the bearings and the pipe, which easily wears down the pipe wall and the bearings themselves, leading to a short service life.

[0006] Therefore, there is an urgent need for drag-reducing devices that increase the contact area between the drag-reducing device and the inner wall of the pipe, reduce wear, and extend service life. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a drag-reducing roller for cable laying, which solves the problem that existing drag-reducing devices use bearings as drag-reducing rollers, resulting in small contact areas that are prone to wear and thus shorten the service life of the drag-reducing device.

[0008] The present invention adopts the following technical solution: a drag-reducing roller for cable laying, comprising a steel ring and a rolling assembly; A steel ring is fitted and fixed to the outer surface of the cable, wherein the inner diameter of the steel ring matches the outer diameter of the cable; Multiple rolling components are circumferentially and evenly mounted on the outer surface of the steel ring. Each rolling component includes a support frame and drum-shaped balls. The support frame is fixed on the steel ring. The drum-shaped balls in all rolling components are mounted on the support frame at equal distances relative to the outer surface of the steel ring. The curvature of the generatrix of the drum-shaped balls is equal to the curvature of the inner wall of the pipeline.

[0009] Furthermore, the number of rolling components is six, and adjacent rolling components are alternately installed on the steel ring in two different ways; in one way, the support frame is arranged axially along the steel ring, and the axis of the corresponding first drum-shaped ball is perpendicular to the axis of the cable; in the other way, the support frame is arranged radially along the steel ring, and the axis of the corresponding second drum-shaped ball is parallel to the axis of the cable. The steel ring is sleeved and fixed on the outer surface of the cable, and the inner diameter of the steel ring matches the outer diameter of the cable. Furthermore, the radius of the first drum-shaped ball is: ; in, Let L be the maximum radius of the first drum-shaped ball, and L be the total axial length of the first drum-shaped ball 201. A one-dimensional coordinate system is established along the axial direction of the ball, with the midpoint of the first drum-shaped ball's axis as the origin. Let x be the axial distance from any point on the first drum-shaped ball to the origin, with a value range of: .

[0010] Furthermore, the steel ring includes two steel plates, one end of which is fixedly connected by a hinge, and the other end is provided with a connecting boss. The two steel plates are detachably connected by a connecting bolt passing through the connecting boss. The height of the connecting boss is lower than that of the support frame.

[0011] Furthermore, a rubber washer is provided on the inner wall of the steel ring, and the height of the rubber washer is higher than that of the inner wall of the steel ring, so as to form a flexible contact with the cable.

[0012] Furthermore, the support frame and the steel ring are connected by springs.

[0013] Furthermore, the drum-shaped ball is mounted on the rotating shaft via a bearing, and a first flat washer is installed between the end face of the drum-shaped ball and the support frame.

[0014] Furthermore, the bearing is made of duplex steel and uses a fluororubber double-lip seal, which is filled with calcium sulfonate compound grease or lithium-based grease.

[0015] Furthermore, the steel ring, support frame, and drum-shaped ball bearings are made of duplex steel.

[0016] Furthermore, the surface of the drag-reducing roller is provided with a metal thermal spray coating and a sealing coating covering the metal thermal spray coating.

[0017] The beneficial effects of this invention are compared with those of the prior art: This invention uses two steel plates connected by hinges to fasten onto the outer surface of the cable, reducing the difficulty of installing the steel ring. The rolling assembly uses drum-shaped balls, and the curvature of the drum-shaped ball's generatrix is ​​the same as the curvature of the pipe, which increases the contact area between the rolling assembly and the pipe, reduces wear on the pipe wall, and effectively extends the service life of the drag-reducing rollers. A drag-reducing roller is installed at predetermined intervals on the cable to ensure uniform force distribution and stable laying within the pipe.

[0018] This invention enables the cable to move axially along the pipe using a first drum-shaped ball bearing and circumferentially along the pipe using a second drum-shaped ball bearing, facilitating cable position adjustment within the pipe. Furthermore, the maximum radius of the first and second drum-shaped balls is determined by the target rolling resistance value, ensuring smooth rolling and reducing installation difficulty.

[0019] The support frame and steel ring of this invention are connected by a spring. The spring can accommodate the processing errors of the drum-shaped roller and the pipe, ensuring the effectiveness of rolling transportation and avoiding the inability to achieve rolling due to the drum-shaped roller and the pipe not making contact due to processing errors. Attached Figure Description

[0020] Figure 1 This is a front view of the cable laying drag-reducing roller of the present invention; Figure 2 This is a right view of the cable laying drag-reducing roller of the present invention; Figure 3 This is a schematic diagram of the detachable connection structure of the present invention; Figure 4 This is a schematic diagram of the bearing structure of the present invention; Figure 5 This is a schematic diagram of the rolling component structure of the present invention; Figure 6 This is a front view of the cable laying drag-reducing roller of Embodiment 2 of the present invention; Figure 7 This is a right view of the cable laying drag-reducing roller in Embodiment 2 of the present invention.

[0021] In the diagram: 1. Hinge, 2. Drum-shaped ball bearing, 3. Shaft, 4. Connecting bolt, 5. Rubber washer, 6. Steel ring, 7. First flat washer, 8. Bearing, 9. Flat washer, 10. First spring washer, 11. Nut, 12. Second spring washer, 13. Support frame, 14. Second flat washer, 15. Second nut. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0023] Reference Figures 1 to 5 Embodiment 1 of the present invention provides a drag-reducing roller for cable laying. As a drag-reducing measure, its design and application directly affect the efficiency and safety of laying submarine cables in pipelines. Figures 1 to 2 As shown, the drag-reducing roller for cable laying includes a steel ring 6, a hinge 1, a connecting bolt 4, and a rolling assembly.

[0024] The steel ring 6 comprises two steel plates, connected at one end by a hinge 1, and at the other end by a connecting boss. The height of the connecting boss is lower than the height of the support frame 13. A connecting bolt 4 passes through the connecting boss, and a flat washer 9 is installed between the bolt head of the connecting bolt 4 and the surface of the boss. A second spring washer 10 is fitted onto the connecting bolt 4 and pressed against the other boss surface by a nut 11 screwed onto the bolt shank. The two connected steel plates form an annular steel ring 6, which is fitted onto the outer surface of the cable. The inner diameter of the steel ring 6 is equal to the outer diameter of the cable. A rubber washer 5 is provided inside the steel ring 6, sandwiched between the steel ring 6 and the cable. The materials for the hinge 1, steel plates, second flat washer 14, second spring washer 12, nut 11, and connecting bolt 4 can be duplex steel 2205.

[0025] There are six rolling components, evenly distributed around the outer surface of the steel ring 6. Each rolling component includes a support frame 13 and drum-shaped balls. The support frame 13 is fixed to the steel ring 6, and the drum-shaped balls are fixed to the support frame 13.

[0026] like Figure 4 and Figure 5As shown, a rotating shaft 3 is provided on the support frame 13. A second flat washer 14 is provided between the rotating shaft 3 and the support frame 13. A drum-shaped ball bearing passes through the rotating shaft 3. A bearing 8 is installed between the drum-shaped ball bearing and the rotating shaft 3. A first flat washer 7 is installed between the end face of the drum-shaped ball bearing and the support frame 13. A second nut 15 is screwed onto one end of the rotating shaft 3. A second spring washer 12 is installed between the second nut 15 and the support frame 13 bracket, and is tightened onto the support frame 13 by screwing the second nut 15 onto the bolt rod. The bearing 8 is a duplex steel 2205 ball bearing. The bearing 8 is lubricated with a lifetime-filled calcium sulfonate composite grease, and sealed with a 2RSFKM double-lip fluororubber seal. A first spring washer 10 is also provided between the drum-shaped ball bearing and the support frame 13. The first spring washer 10 is a metal washer, which creates a gap between the drum-shaped ball bearing and the support frame 13. When the entire device is working, fine sand will not accumulate between the support frame 13 and the ball bearing, improving the reliability of the device. The materials for the support frame 13, the drum-shaped ball bearing, the rotating shaft 3, the first flat washer 7, and the first spring washer 10 can be duplex steel 2205.

[0027] The surfaces of hinge 1, steel sheet, second flat washer 14, second spring washer 12, nut 11, connecting bolt 4, support frame 13, drum-shaped ball, shaft 3, first flat washer 7 and first spring washer 10 are coated with metal thermal spraying and sealing coating. The metal thermal spraying uses aluminum, then low viscosity epoxy is used for sealing coating, and finally intermediate paint and topcoat are applied.

[0028] The boundary curve of the outer contour of the drum-shaped ball on its cross-section through the axis is the generatrix. The curvature of the generatrix is ​​the same as the curvature of the pipe. The axis of the first drum-shaped ball 201 is perpendicular to the axis of the cable. This is used to increase the contact surface between the ball and the steel pipe during cable laying, while reducing the generation of acute angles.

[0029] The radius of the first drum-shaped ball 201 is: ; in, Let L be the maximum radius of the first drum-shaped ball 201, and L be the total axial length of the first drum-shaped ball 201. A one-dimensional coordinate system is established along the ball axis with the midpoint of the first drum-shaped ball 201 as the origin. Let x be the axial distance from any point on the first drum-shaped ball 201 to the origin, with a value ranging from [value missing]. .

[0030] The range of values ​​for x and In coordination, from arrive The radius of the first drum-shaped ball 201 is from The value of x decreases continuously to 0, completely describing the outer contour of the first drum-shaped ball 201. Therefore, the range of x is... arrive It can accurately calculate the maximum radius of the drum-shaped balls used, ensuring continuous and smooth rolling contact.

[0031] Take the axial micro-element segment The infinitesimal normal pressure borne by this segment Rolling resistance of micro-segments .

[0032] Axial rolling resistance value .

[0033] in, The coefficient of rolling friction is The pressure exerted on the first drum-shaped ball 201.

[0034] As can be seen from the above analysis, the resistance of the first drum-shaped ball 201 during rolling is determined by its maximum radius. To ensure the resistance reaches a preset value, the radius of the first drum-shaped ball 201 is designed as follows: The maximum radius of the first drum-shaped ball 201 is: ; in, Taking 0.01 as an example, Taking 500N as an example, This represents the target axial rolling resistance value.

[0035] The resistance value of axial rolling is determined only by the maximum radius of the first drum-shaped ball 201 and is independent of the axial distance from any point on the first drum-shaped ball 201 to the origin of the coordinate system. By inferring the maximum radius of the first drum-shaped ball 201 from the target resistance, the quantitative design of the drag-reducing roller can be realized, avoiding the defect that the size of the drum-shaped ball in the drag-reducing roller structure can only be selected based on experience.

[0036] The calculations for common pipelines were performed using the formulas described above, and the data shown in Table 1 were obtained.

[0037] Table 1. Maximum selectable radius for the first drum-shaped ball bearing in common pipelines.

[0038] Applying lithium-based grease can reduce the rolling friction coefficient, thereby reducing the resistance value.

[0039] Reference Figures 6-7 Embodiment 2 of the present invention provides a drag-reducing roller for cable laying, which is otherwise the same as that in Embodiment 1, except that the support frame 13 and the steel ring 6 are connected by a spring to accommodate processing errors and to be suitable for pipes of more sizes. The surface of the drum-shaped ball is covered with wear-resistant rubber to extend its service life.

[0040] like Figure 6 and Figure 7To enable the drag-reducing rollers to achieve both axial and circumferential rolling, the number of rolling components is six, including three first drum-shaped balls 201 arranged axially along the steel ring 6 with their axes perpendicular to the cable axis, and three second drum-shaped balls 202 arranged radially along the steel ring 6 with their axes parallel to the cable axis. The first drum-shaped balls 201 and the second drum-shaped balls 202 are arranged alternately at equal intervals along the circumference of the steel ring 6.

[0041] According to the calculation process in Example 1, the maximum radius of the first drum-shaped ball 201 is... .

[0042] The circumferential rotational resistance is less than the axial rolling resistance, and the maximum radius of the second drum-shaped ball 2 is: ; in, The target circumferential rolling resistance value.

[0043] The calculations for common pipelines were performed using the formulas described above, and the data shown in Table 2 were obtained.

[0044] Table 2. Maximum selectable radius for the second drum-shaped ball bearings in common pipelines.

[0045] Axial rolling and circumferential rotation can occur simultaneously, and the total resistance is the vector sum of the resistances under both conditions.

[0046] During construction, the size and quantity of the drag-reducing roller device are determined based on the cable model parameters. The drag-reducing roller device is installed on the cable at regular intervals, and the cable is then pulled and laid. The drag-reducing roller device assists in the cable laying.

[0047] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A drag-reducing roller for cable laying, comprising a steel ring (6) and a rolling assembly; characterized in that, Includes a steel ring (6), which is fitted and fixed on the outer surface of the cable, wherein the inner diameter of the steel ring (6) matches the outer diameter of the cable; Multiple rolling components are circumferentially and evenly installed on the outer surface of the steel ring. Each rolling component includes a support frame (13) and drum-shaped balls. The support frame (13) is fixed on the steel ring (6). The drum-shaped balls in all rolling components are installed on the support frame (13) at equal distances relative to the outer surface of the steel ring. The curvature of the drum-shaped ball generatrix is ​​equal to the curvature of the inner wall of the laying pipe.

2. The drag-reducing roller for cable laying according to claim 1, characterized in that, The number of rolling components is six, and adjacent rolling components are installed on the steel ring (6) in two different ways. In one way, the support frame (13) is arranged axially along the steel ring (6), and the axis of the corresponding first drum-shaped ball (201) is perpendicular to the axis of the cable. In the other way, the support frame (13) is arranged radially along the steel ring (6), and the axis of the corresponding second drum-shaped ball (202) is parallel to the axis of the cable.

3. The drag-reducing roller for cable laying according to claim 1, characterized in that, The radius of the first drum-shaped ball 201 is: ； in, Let L be the maximum radius of the first drum-shaped ball (201), and L be the total axial length of the first drum-shaped ball (201). A one-dimensional coordinate system is established along the ball's axial direction, with the midpoint of the first drum-shaped ball (201) as the origin. Let x be the axial distance from any point on the first drum-shaped ball (201) to the origin, with a range of values ​​as follows: 。 4. The drag-reducing roller for cable laying according to claim 1, characterized in that, The steel ring (6) includes two steel plates. One end is fixedly connected by a hinge (1), and the other end is provided with a connecting boss. The two steel plates are detachably connected by a connecting bolt (4) passing through the connecting boss. The height of the connecting boss is lower than that of the support frame (13).

5. The drag-reducing roller for cable laying according to claim 1, characterized in that, The inner wall of the steel ring (6) is provided with a rubber gasket (5), the height of which is higher than the inner wall of the steel ring (6), for forming a flexible contact with the cable.

6. The drag-reducing roller for cable laying according to claim 1, characterized in that, The support frame (13) and the steel ring (6) are connected by a spring.

7. The drag-reducing roller for cable laying according to claim 1, characterized in that, The drum-shaped ball (2) is mounted on the rotating shaft (3) via a bearing (8), and a first flat washer (7) is installed between the end face of the drum-shaped ball (2) and the support frame (13).

8. The drag-reducing roller for cable laying according to claim 7, characterized in that, The bearing is made of duplex steel and uses a fluororubber double-lip seal, which is filled with calcium sulfonate compound grease or lithium-based grease.

9. The drag-reducing roller for cable laying according to claim 1, characterized in that, The steel ring (6), support frame (13) and drum-shaped ball (2) are made of duplex steel.

10. The drag-reducing roller for cable laying according to claim 1, characterized in that, The surface of the drag-reducing roller is provided with a metal thermal spray coating and a sealing coating covering the metal thermal spray coating.

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