Bending machine

Abstract

A bending machine (50) for manufacturing a reinforced tube or tube section (10) comprising a metal tube or tube section having a bottom of thickness t and diameter D, and at least one first metal reinforcing element on an inner surface along a circumference of the metal tube or tube section (10), 5 wherein the bending machine (50) comprises an inner roller (51) and two outer rollers (52), wherein the outer surface of the inner roller (51) comprises at least one groove (55) for accommodating the at least one first metal reinforcing element (2).

Description

Technical Field

[0001] The present invention relates to a bending machine. Background Art

[0002] The offshore floating wind industry is growing. As sizes increase, new wind turbine designs are being developed. Therefore, new buoyancy tanks that are lightweight and strong must be provided in an efficient manner in order to produce floating structures with sufficient buoyancy at the lowest possible cost.

[0003] The present invention relates to a method for manufacturing cylinders, and more particularly to a method for manufacturing reinforced cylinders, tubes, and tube sections that can be used as buoyancy members for offshore floating wind turbine structures or other large-diameter thin-shell structures. So far, one solution has been to reduce the wall thickness to reduce the steel weight and thus the cost of floating offshore structures.

[0004] Conventional techniques for manufacturing ring-reinforced structures include bending a metal sheet to form a structure such as a tube and then welding ring elements onto the inside of the tube. For structures with a relatively large diameter-to-wall-thickness ratio (such as tubes), this method is associated with problems related to buckling due to the self-weight of the sheet during metal sheet bending. This is also the case if spiral welding of tubes using conventional techniques is used as the manufacturing method. Welding in the ring reinforcement elements after sheet bending is also expensive because it involves additional operations, including additional handling during the manufacture of the reinforced shell. One solution to this is to design flat buoyancy members instead of cylinders. A flat structure can be easily reinforced with T-beams by welding the T-beams to the shell plate when the shell plate is in a flat position on the floor. This is a well-known manufacturing method in the shipbuilding industry. Therefore, the production cost per kilogram of steel for flat reinforced plates is lower than that of circular reinforced plates. However, flat buoyancy members will have higher hydrodynamic excitation forces, so a floating foundation carrying the same wind turbine will require more steel.

[0005] Therefore, new production methods have been developed in order to mitigate the problems of existing methods for manufacturing reinforced thin-walled shells. Summary of the Invention

[0006] The present invention is defined by the appended claims and is set forth below:

[0007] In a first aspect, the present application describes a method for manufacturing a reinforced tube section, which comprises the following steps:

[0008] a) providing a first metal sheet having a thickness t,

[0009] b) providing at least one first metal reinforcement element and placing the at least one first metal reinforcement element on the first metal sheet;

[0010] c) Bend the first metal plate together with the at least one first metal reinforcing element to form a tube section, and

[0011] d) Weld the at least one first metal reinforcing element to the first metal plate,

[0012] where steps c) and d) can be carried out in any order.

[0013] In one embodiment of the method, the tube section has a bending diameter D, and the ratio D / t can be at least 100, at least 150, at least 200, at least 250, at least 300 or at least 500.

[0014] Those skilled in the art will understand that the bending diameter is the diameter of the circle along which the metal plate is bent.

[0015] In one embodiment, the ratio D / t can be between 100 and 1500; preferably between 200 and 800.

[0016] In one embodiment, the order of steps in the method is a), then b), then d), then c). In other words, first weld the at least one first metal reinforcing element to the first metal plate to form a reinforced metal plate, and then bend the reinforced metal plate to form a reinforced tube section.

[0017] In one embodiment, the order of steps in the method is a), then b), then c), then d). In other words, first bend the first metal plate together with the at least one first metal reinforcing element to form a tube section, and then weld the at least one first metal reinforcing element to the tube section to form a reinforced tube section.

[0018] In one embodiment, the welding step d) is carried out after step c) and within 360° of the bend line (i.e., the line on the metal plate along which the metal plate is bent); and this angle is defined between the radius of the circle along which the metal plate is bent starting from the bend line and a second radius of the circle along which the metal plate is bent starting from the welding point.

[0019] In one embodiment, the welding step d) is carried out after step c) and within 270°, 180°, 135°, 90°, 60°, 45° or 30° of the bend line.

[0020] In one embodiment, the thickness t can be 50 mm or less, 40 mm or less, 30 mm or less, 25 mm or less, 20 mm or less, 15 mm or less, or 10 mm or less.

[0021] In one embodiment, the thickness t can be between 10 mm and 500 mm, preferably between 15 mm and 200 mm.

[0022] In one embodiment, the diameter D can be between 5 m and 50 m; preferably between 8 m and 30 m.

[0023] In one embodiment, the width of the metal plate is 10 times, 20 times, 50 times, 100 times, 500 times, 1000 times the width of the first metal reinforcing element.

[0024] In one embodiment, at least one first metal reinforcing element is placed on the first metal plate in the bending direction. For example, if at least one first metal reinforcing element is a beam, it is placed perpendicular to the axis of rotation on the metal plate, and the metal plate and at least one first metal reinforcing element are bent around the axis of rotation.

[0025] In one embodiment, the welding step b) can include welding at least two, at least three, at least four, at least five or at least ten first metal reinforcing elements to the first metal plate.

[0026] In one embodiment, the welding step b) can include welding at least two first metal reinforcing elements to the first metal plate, and the at least two first metal reinforcing elements are parallel to each other.

[0027] In one embodiment, at least two first metal reinforcing elements are parallel, and the distance between the at least two first metal reinforcing elements is between 1 / 50 and 1 / 4 of the tube diameter D, preferably between 1 / 30 and 1 / 6 of the tube diameter D.

[0028] In one embodiment, the method can further include the following steps:

[0029] e) Welding at least one second metal reinforcing element to the first metal plate at an angle to the at least one first metal reinforcing element.

[0030] In one embodiment, at least one second metal reinforcing element is perpendicular to at least one first metal reinforcing element.

[0031] In one embodiment, the welding step d) can include welding at least two, at least three, at least four, at least five or at least ten second metal reinforcing elements to the first metal plate.

[0032] In one embodiment, the tube section is a full tube, a half tube or a quarter tube.

[0033] In one embodiment, the tube section is a cylinder or a conical cylinder having a substantially circular or oval base.

[0034] In one embodiment, the tube section is a spiral or conical spiral with a distinctly circular or oval bottom.

[0035] In one embodiment, the method may further comprise the steps of:

[0036] f) bending at least one end portion of the first metal plate to substantially the same curvature as the remainder of the tube section between steps a) and b), and

[0037] cutting at least one end portion of the at least one first reinforcing element such that the end portion of the at least one first reinforcing element has substantially the same curvature as the end portion of the first metal plate.

[0038] In one embodiment, the method may further comprise the steps of:

[0039] g) bending two end portions of the first metal plate to substantially the same curvature as the remainder of the tube section between steps a) and b), and

[0040] cutting two end portions of the at least one first reinforcing element such that the end portions of the at least one first reinforcing element have substantially the same curvature as the end portions of the first metal plate.

[0041] Here, those skilled in the art will understand that the end portions of the metal plate or the at least one first reinforcing element are the portions of the metal plate or the at least one first reinforcing element near the edges of the plate, which edges will contact each other when forming a cylinder.

[0042] In one embodiment, the first metal plate may have a yield strength of at least 200 MPa, at least 250 MPa, at least 300 MPa or at least 400 MPa.

[0043] In one embodiment, the first metal plate may be made of steel, steel alloy, aluminum or aluminum alloy.

[0044] In one embodiment, the at least one first reinforcing element may be a T-beam or a U-beam.

[0045] In one embodiment, the at least one first reinforcing element may be made of steel, steel alloy, aluminum or aluminum alloy.

[0046] In one embodiment, the at least one second reinforcing element may be made of steel, steel alloy, aluminum or aluminum alloy.

[0047] In one embodiment, the at least one first reinforcing element and the first metal plate are made of the same material.

[0048] In one embodiment, at least one second reinforcing element and the first metal plate are made of the same material.

[0049] In one embodiment, the ratio of the structural capacity of the reinforcing tube section to the structural capacity of the first metal plate can be at least 5, preferably at least 10.

[0050] In one embodiment, at least one first reinforcing element can be oriented in one direction on the first metal plate such that when a cylinder is formed, at least one first reinforcing element forms a complete ring along the inner perimeter of the cylinder, or forms a substantially complete ring if a small gap is left for final welding at a later stage.

[0051] In one embodiment, at least one second reinforcing element is welded in a direction orthogonal to at least one first reinforcing element.

[0052] In one embodiment, the method further includes welding a second metal plate to at least one first metal reinforcing element, wherein the second metal plate is parallel to the first metal plate.

[0053] In one embodiment, the second metal plate can be made of steel, steel alloy, aluminum, or aluminum alloy.

[0054] In a second aspect, the present application describes a reinforced tube, comprising:

[0055] - a first metal tube having a thickness t and a bottom with a diameter D,

[0056] - at least one first metal reinforcing element welded to the inner surface of the reinforced tube.

[0057] In one embodiment, the D / t ratio of the reinforced tube exceeds 100.

[0058] In one embodiment of the second aspect, the ratio D / t can be between 100 and 1500, preferably between 200 and 800.

[0059] In a third aspect, the present invention relates to a bending machine for manufacturing a reinforced tube or tube section, the reinforced tube or tube section comprising a metal tube or tube section having a thickness t and a bottom with a diameter D, and at least one first metal reinforcing element welded along the circumference to the inner surface of the metal tube section,

[0060] wherein the bending machine includes an inner roll and two outer rolls, and the outer surface of the inner roll or the outer rolls includes at least one first groove for receiving at least one first metal reinforcing element.

[0061] In one embodiment of the third aspect, the ratio D / t is at least 100.

[0062] In an embodiment of the third aspect, the depth of the at least one groove is at least equal to the height of the at least one first metal reinforcing element.

[0063] In an embodiment of the third aspect, the depth of the at least one groove may be substantially equal to the height of the at least one first metal reinforcing element.

[0064] In an embodiment, the bending machine may further include means for welding at least one first metal reinforcing element to the metal tube section, such as a welding arm for automatic welding.

[0065] In an embodiment, the bending machine may further include at least two spacers. A spacer is an object that can be placed on each side of the at least one first reinforcing element and between the first metal plate and the inner roller.

[0066] In an embodiment, each spacer may include a vertically acting spacer roller. The vertically acting spacer roller transfers the pressure of the inner roller to the first metal plate.

[0067] In an embodiment, each spacer may include at least one laterally acting spacer roller. The laterally acting spacer roller is placed on each side of the at least one first reinforcing element, preferably in contact with the at least one first reinforcing element, and applies sufficient pressure on the at least one first reinforcing element to prevent the at least one first reinforcing element from buckling.

[0068] In an embodiment, each spacer may include two laterally acting spacer rollers.

[0069] In an embodiment, each spacer may be freestanding. That is, each spacer does not need to be attached to another structure.

[0070] In an embodiment, the bending machine may further include a support roller. A support roller is a roller that supports the formed reinforced tube to further help avoid buckling or bending of the helix, tube, or reinforced tube under its own weight.

[0071] In an embodiment, the height and position of the support roller may be adjustable. This advantageously allows changing the orientation of the longitudinal axis of the reinforced tube during the production of the reinforced tube / during the operation of the bending machine.

[0072] In an embodiment, a series of vertical rollers may be spaced along the bending axis on the roller arm member for manufacturing a helical tube in the bending machine. The bending machine may further include lateral rollers to support the metal reinforcing element during plastic bending of the first metal reinforcing element in the bending machine. The series of vertical rollers may be oriented at a feed angle such that the axis of rotation is substantially perpendicular to the first metal plate entering the bending machine for manufacturing the reinforced tube.

[0073] In one embodiment, a series of first metal reinforcing elements may be welded to a first metal plate at an angle orthogonal to the longitudinal axis of the produced spiral tube. The metal plate with the metal reinforcing elements may then be fed into a bending machine during the production of the reinforced spiral tube. The bending machine may include a spiral inner roll which may ensure the contact pressure on the first metal plate and on the first metal reinforcing elements, while preventing the first metal reinforcing elements from colliding with the rolls in the bending machine during the continuous manufacture of the spiral tube.

[0074] In one embodiment, during the operation of the bending machine, the orientation of the inner roll and the outer roll may be adjusted relative to the longitudinal axis of the reinforced tube. This advantageously allows changing the orientation of the longitudinal axis of the reinforced tube during production.

[0075] In one embodiment, the first groove of the inner roll of the bending machine may be a spiral groove.

[0076] In one embodiment, the inner roll may include a series of inner rolls and lateral rolls arranged on inner roll support arms, or the outer roll includes a series of outer rolls and lateral rolls arranged on outer roll support arms.

[0077] In a fourth aspect, the application of the present invention describes a method for manufacturing a reinforced pipe section for joining, which includes the following steps:

[0078] a) Providing a first metal plate having a thickness t;

[0079] b) Bending the first metal plate to form a first pipe section of up to 340°;

[0080] c) Providing a prefabricated reinforced pipe section, aligning the prefabricated reinforced pipe section and the first pipe section along their longitudinal axes, and welding the first pipe section to the prefabricated reinforced pipe section along their circumferences;

[0081] d) Providing at least one prefabricated first metal reinforcing element;

[0082] e) Positioning the at least one prefabricated first metal reinforcing element along the inner or outer perimeter of the first pipe section, and welding the at least one prefabricated first metal reinforcing element to the first pipe section, thereby forming a joined reinforced joined pipe section.

[0083] In one embodiment of the method according to the fourth aspect, the at least one prefabricated first metal reinforcing element forms a complete circle or substantially a complete circle.

[0084] Here, those skilled in the art will understand that "the first metal reinforcing element forms a complete circle or substantially a complete circle" means that the reinforcing element forms a circle or substantially a circle in cross-section.

[0085] In one embodiment of the method according to the fourth aspect, at least one prefabricated first metal reinforcing element is positioned along the inner periphery of the first tube section.

[0086] In one embodiment of the method according to the fourth aspect, at least one prefabricated first metal reinforcing element is positioned along the outer periphery of the first tube section.

[0087] In one embodiment of the method according to the fourth aspect, the prefabricated reinforced tube section is a tube (i.e., a 360° tube section), and the method may further include the following steps:

[0088] f) Further bending the first metal plate to form a first tube section that is substantially 360°.

[0089] Here, those skilled in the art will understand that the first tube section and the prefabricated reinforced tube section have substantially the same diameter and are aligned such that the longitudinal axes of the first tube section and the prefabricated reinforced tube section are aligned and placed adjacent to each other. The first tube section and the prefabricated reinforced tube section are welded along the contact point, in other words, welded along the circumference of the bottom of the tube section.

[0090] In one embodiment, the prefabricated reinforced tube section is obtained according to the first aspect of the present invention.

[0091] In one embodiment of the method according to the fourth aspect, the joined reinforced tube section and the first tube section have a bending diameter D, and the ratio D / t can be at least 100, at least 150, at least 200, at least 250, at least 300, or at least 500.

[0092] Those skilled in the art will understand that the bending diameter is the diameter of the circle along which the metal plate is bent.

[0093] In one embodiment, the ratio D / t can be between 100 and 1500; preferably between 200 and 800. Description of the Drawings

[0094] In the following description, the present invention will be further explained by means of exemplary embodiments shown in the drawings:

[0095] Figure 1a is a side view of a first embodiment of a series of first metal reinforcing elements welded to a first metal plate.

[0096] Figure 1b is a perspective view of a first embodiment of a series of first metal reinforcing elements welded to a first metal plate.

[0097] Figure 2a is a side view of a second embodiment of a series of first metal reinforcing elements welded to a first metal plate and welded to a second metal plate.

[0098] Figure 2b Is a perspective view of a second embodiment of a series of first metal reinforcing elements welded to a first metal plate and welded to a second metal plate.

[0099] Figure 3a Is a side view of the first metal plate and the first metal reinforcing element during bending and subsequent welding at an angle α.

[0100] Figure 3b Is a side view of the first metal plate and the first metal reinforcing element during bending and subsequent welding of the first metal reinforcing element at an angle β.

[0101] Figure 4a Is a perspective view of a series of first metal reinforcing elements welded to a first metal plate and bent into a helix and welded to a second metal plate.

[0102] Figure 4b Is a perspective view of an embodiment in which the first metal plate is bent into a helix and then the weld seam is welded.

[0103] Figure 5 Is a side view of an embodiment in which the reinforced metal plate is bent into a helix and then the weld seam is welded at an angle α.

[0104] Figure 6 Is a perspective view of a first embodiment of a bending machine

[0105] Figure 7 Is a perspective view of a second embodiment of a bending machine

[0106] Figure 8 Is a perspective view of a first embodiment of a series of first metal reinforcing elements welded to a first metal plate and spacers

[0107] Figure 9 Is a perspective view of a second embodiment of a series of first metal reinforcing elements welded to a first metal plate and spacers

[0108] Figure 10 Is a front view of a bending machine including spacers

[0109] Figure 11 Is a perspective view of a series of first metal reinforcing elements and a first metal plate passing through a bending machine including spacers

[0110] Figure 12 Is a detailed view of a series of first metal reinforcing elements and a first metal plate passing through a bending machine including spacers

[0111] Figure 13Detailed view of a series of first metal reinforcement elements and a first metal plate passing through a bending machine, the bending machine including a series of vertical and lateral rollers arranged on inner roller support arms.

[0112] Figure 14 Top view of an embodiment in which a series of first metal reinforcement elements are longitudinally welded to a first metal plate, the first metal plate being fed into the bending machine at a feed angle, each inner roller being arranged on an inner roller support arm, the axis of rotation of which is arranged at an angle δ (delta) relative to the longitudinal axis of the helix.

[0113] Figure 15 Top view of an embodiment in which a series of first metal reinforcement elements are welded to a first metal plate 1 at an angle orthogonal to the longitudinal axis of the helix, the metal plate being fed into a bending machine including a helical inner roller.

[0114] Figure 16 Perspective view of a series of first metal reinforcement elements welded to a first metal plate, bent into a helix and welded to a second metal plate.

[0115] Figure 17 Perspective view of a flat plate bent into a helix and welded to other elements to form a reinforced tube. Detailed description of the embodiments

[0116] In the design of offshore floating wind farms, reducing the weight of materials is necessary to ensure low costs for energy production. At the same time, the structure needs to maintain its strength in order to be able to withstand environmental mechanical stresses.

[0117] Therefore, new structures with an increasingly large ratio of tube diameter to wall thickness have been developed, especially buoyancy tanks. For example, it is not uncommon to use buoyancy tanks with a diameter greater than 11 m and a wall thickness of only about 20 mm.

[0118] For tubes with a relatively large ratio of tube diameter to wall thickness, traditional production methods are associated with problems related to buckling of the plate due to the gravitational force acting on the plate during bending. Additionally, welding rings after forming the complete tube is a complex, time-consuming and expensive operation.

[0119] Therefore, in order to mitigate the problems of the existing methods, new production methods have been developed.

[0120] Traditional techniques for manufacturing reinforced tube sections or tubes include first bending a metal plate, then forming a tube, and then welding metal reinforcement elements to the formed cylinder.

[0121] Here, the person skilled in the art will understand that the method can be used to form tubes, such as cylinders and conical cylinders. A conical cylinder is equivalent to a frustum. The method is also suitable for forming partial cylinders or partial conical cylinders.

[0122] Those skilled in the art will also understand that any type of welding can be used here, including tack welding before performing the final welding at a later stage.

[0123] An example of this method is shown, for example, in Figure 5 . Specifically, this method proposes bending at least one first reinforcing element 2 together with the metal plate 1 to form a tube section 10. Another example of this method is shown in Figure 4b . Details and alternatives are shown in other figures. Specifically, this method proposes bending the metal plate 1 along the bending line to form a helix, where the pitch of the helix is substantially equal to the width of the plate, and where two consecutive turns of the helix contact (or are placed in contact) at the seam 20; welding the helix 30 along the seam 20 to form a tube; and welding at least one first metal reinforcing element to the tube, thereby forming a reinforced tube 10.

[0124] Here, those skilled in the art will understand that the reinforcing element 2 can generally be any reinforcing element conventionally used in the oil and gas industry, especially beams such as T-beams and U-beams.

[0125] Due to this method, the metal plates 1 will be able to support their weight during the bending step, and the risk of buckling will be at least reduced or even eliminated.

[0126] In addition, this method allows the process for manufacturing the reinforced tube section 10 to be continuous. In particular, it allows the process for manufacturing a complete reinforced tube (i.e., a tube of any desired length) to be continuous.

[0127] Here, at least one reinforcing element 2 can be bent together with the first metal plate 1, or at least one reinforcing element 2 can be placed on the first metal plate 1 after bending the first metal plate 1.

[0128] At least one reinforcing element 2 can also be welded to the first metal plate before (when there is at least one reinforcing element 2) or after the bending step.

[0129] First Example:

[0130] In the first step, a series of parallel reinforcing elements 2 (here T-beams) are first welded to the flat plate 1, thereby forming a reinforced flat plate 3 as shown in Figure 1a and Figure 1b . Then, the reinforced flat plate 3 is passed through a bending machine 50 to form an annularly reinforced cylindrical tube section 10, and where the T-beams form a circular section.

[0131] In this example, the welding step is implemented before the bending step. In some examples, it may be advantageous to first perform the bending step and then the welding step.

[0132] Alternatively, the reinforced plate 3 is then passed through a bending machine 50 to form a helically reinforced tube or helix 30, and wherein the T-beam also forms a helix. As shown in FIGS. 4 and Figure 5 as shown, a welding arm 59 is used to weld the seam 20 of the helix 30 at an angle α of 10° for example with respect to the bending line (i.e., the line on the metal sheet along which the metal sheet is bent); wherein the angle α is defined as the angle between a first radius of the helix along which the metal sheet is bent starting from the starting point of the bend (or the bending line) and a second radius of the helix starting from the welding point. The formed helix is supported by one or more support rollers 70.

[0133] Second Example

[0134] In a first step, a series of reinforcing elements 2 (here shear webs) are welded to a first flat aluminum sheet 1 and then to a second aluminum sheet 5 such that a shear web is included between the first sheet 1 and the second sheet 5 and such that the first aluminum sheet 1 and the second aluminum sheet 5 are parallel. This results in a double flat deck (or double skin), as Figure 2a and Figure 2b shown. Then, the double flat deck is passed through a bending machine to form an annularly reinforced cylindrical tube section 10 or a helically reinforced tube or helix 30. The seam 20 of the helix 30 is welded at an angle α of 45° with respect to the bending line using a welding arm for example.

[0135] Third Example

[0136] In a first step, a series of parallel first reinforcing elements 2 (here T-beams) are welded to a flat sheet 1. A series of parallel second reinforcing elements 4 (here also T-beams) orthogonal to the series of first reinforcing elements 2 are also welded to the flat sheet 1, thereby forming a reinforced metal sheet 3, the second reinforcing elements 4 being perpendicular to the first reinforcing elements 2.

[0137] As shown in FIG. 4, the reinforced metal sheet 3 is then passed through a bending machine 50 to form an annularly reinforced cylindrical tube section 10. The reinforced tube section 10 is supported by support rollers 70.

[0138] Having a series of second reinforcing elements in an orthogonal direction also reinforces the reinforced tube in the orthogonal direction. This is not necessary but is beneficial for increasing the strength of the final reinforced tube for installation. This also applies to the tube section.

[0139] Fourth Example

[0140] In a fourth example, a series of first reinforcing elements 2 are placed on a metal sheet 1 (without welding). Then, the metal sheet 1 and the reinforcing elements 2 are passed through a bending machine 50, and they are welded shortly after the sheet 1 and the reinforcing elements 2 are bent as shown in FIG. 3. In other words, at least tack welding will advantageously occur at a location near the point where the sheet 1 and the reinforcing elements 2 are plastically bent, and the final welding can occur at a location near the point where the sheet 1 and the reinforcing elements 2 are plastically bent, or at a more remote location, for example, in cases where vibrations from the roll forming operation have a negative impact on the welding quality. In other words, the welding occurs at an angle α with respect to the bend line (i.e., the line on the metal sheet along which the metal sheet is bent); and the angle α is defined between a first radius of the circle along which the metal sheet is bent starting from the bend line and a second radius of the circle along which the metal sheet is bent starting from the welding point. Welding the reinforcing elements 2 to the sheet 1 after plastic bending reduces the combined bending stiffness of the metal sheet 1 and the reinforcing elements 2 during the bending operation, thereby reducing the required bending force and the risk of buckling of the reinforcing elements during the bending operation. This is also advantageous because it will reduce the built-in material strain in the metal sheet and the first reinforcing elements during and after the plastic bending operation.

[0141] Fifth Example

[0142] In a first step, a single reinforcing element 2 (here a T-beam) is first welded to a flat sheet 1, thereby forming a reinforced flat sheet 3. As Figure 5 shown, the reinforced flat sheet is then passed through a bending machine 50 to form a helically reinforced tube. The reinforced tube 10 is supported by a series of support rolls 70.

[0143] After forming a tube of suitable dimensions (here, for example, a tube with a diameter of 10 m, a thickness of 25 mm, and a length of 40 m), the ends are cut so that the tube has a cylindrical shape. Alternatively, the sheet 1 can be pre-cut before entering the bending machine so that the ends of the helically reinforced tube become a cylinder with ends orthogonal to the longitudinal axis of the tube.

[0144] Here, the distance between two first metal reinforcing elements 2 can generally be 500 - 2000 mm.

[0145] Sixth Example

[0146] In a sixth example, as Figure 12As shown, a series of lower abdominal plate members 64 are welded to the metal plate 1, and a series of first reinforcing elements 2 are placed on top of the abdominal plate members 64 (without welding). Then, as shown in FIG. 3, the metal plate together with the abdominal plate members 64 and the reinforcing elements 2 is passed through a bending machine, and is welded together at the intersection 63 shortly after the plate 1 is bent together with the lower abdominal plate members 64 and the reinforcing elements 2 (in other words, the welding occurs at a position not far after the point where the plate 1, the lower abdominal plate members 64, and the reinforcing elements 2 are plastically bent). In other words, after the plastic bending occurs, at the angle α of the bending line, welding the reinforcing element 2 (which has a reduced web height in this example) to the plate 1 including the lower part of the lower abdominal plate membrane 64 further reduces the combined bending stiffness of the metal plate 1 and the reinforcing element 2 during the bending operation, thereby reducing the total bending force required and the risk of buckling of the reinforcing element during the bending operation.

[0147] In this example, a part of the welding step is implemented before the bending step, and another part is implemented after the bending step, so as to reduce the stiffness of the web and the flange and the risk of buckling of the web and the flange during the bending operation, and reduce the post-bending plastic (and permanent) strain in the bent material. A high level of plastic strain may initiate microcracks in the material and thus reduce the fatigue strength of the bent material, so it should be expected to be reduced as much as possible during manufacturing.

[0148] Seventh Example

[0149] In the first step, the first flat metal plate 1 is passed through a bending machine to form a 340° circular tube section. The formed tube section is welded to a previously produced (or prefabricated) reinforced tube section. The first metal plate 1 is further bent by a total of substantially 360° using the bending machine, and the first metal plate is welded to the reinforced tube section. At least one metal reinforcing element 2 is independently manufactured to form a complete circle or substantially a complete circle, and is positioned inside the tube section. Then, at least one first metal reinforcing element 2 is welded to the tube section to form a joined reinforced tube section. Welding the reinforcing element 2 to the plate 1 after plastic bending reduces the combined bending stiffness of the metal plate 1 and the reinforcing element 2 during the bending operation, thereby reducing the bending force required and the risk of buckling of the reinforcing element during the bending operation.

[0150] Eighth Example

[0151] In the eighth example, a series of first reinforcing elements 2 are placed on the metal plate 1 (without welding). Then the metal plate 1 and the reinforcing elements 2 are passed through a bending machine 50 to form a spiral reinforced tube or helix 30. For example, a welding arm is used to weld or at least position-weld the seam 20 of the helix 30 at an angle α of 10° with respect to the bending line. As Figure 3aAs shown, shortly after the bending of the plate 1, a series of first reinforcing elements 2 are welded (in other words, the welding occurs not far after or at the point of plastic bending of the plate). In other words, it forms a second angle β with the bending line (i.e., the line on the metal plate along which the metal plate bends); and the angle β is defined between the radius of the circle along which the metal plate bends starting from the bending line and the second radius of the circle along which the metal plate bends starting from the welding point (of the metal reinforcement 2). Here ( Figure 3a ) the angle β is about 85° with respect to the bending line. For submerged arc welding, the optimal welding position is vertically downward, so the preferred angle α is close to 0 degrees or 360 degrees or 720 degrees, etc., for welding from the inside of the pipe, and close to 180 degrees, 540 degrees, etc., for welding from the outside of the pipe. In this example, the main welding of the seam 20 is carried out from the inside at about 10 degrees of α, and the back welding of the seam 20 (which is a smaller weld to avoid root defects in the finished weld) is carried out from the outside at 180 degrees of β.

[0152] In this example, the seam is welded first, and then the first reinforcing element 2 is welded, that is, α < β. α = β or α > β is also possible.

[0153] Ninth Example

[0154] In the first step, a single reinforcing element 2 (here a U-shaped beam) is first welded to the flat plate 1 to form a reinforced metal plate 3. Then the reinforced metal plate is passed through a bending machine 50 to form a spiral reinforced pipe. After forming a pipe of appropriate size (here for example a pipe with a diameter of 10 m, a thickness of 25 mm and a length of 40 m), the ends are cut so that the pipe has a cylindrical shape.

[0155] Here, the distance between two first metal reinforcing elements 2 can generally be 500 - 2000 mm.

[0156] Tenth Example

[0157] In the first step, the metal plate 1 is passed through a bending machine 50 to form a spiral pipe or helix 30. After the first turn, for example, the seam 20 of the helix 30 is welded at an angle α of 10° with respect to the bending line using a welding arm. At least one metal reinforcing element 2 is independently manufactured to form a complete circle or substantially a complete circle, and as Figure 4b shown, it is laterally positioned inside the welding machine 50 on the sides of the rollers 51, 52. Then, after the first metal plate 1 is bent at least 360 degrees using the bending machine, that is, starting from the second turn, at least one first metal reinforcing element 2 is welded onto the first helix 30 to form a reinforced pipe 10. In other words, the formed pipe segment is still at least partially in the bending machine 50. Thus, as Figure 4bAs shown, the bent metal plate 1 is structurally supported by adjacent portions of a finished helical pipe segment equipped with metal reinforcing elements during the bending operation to prevent collapse.

[0158] Eleventh Example

[0159] In a first step, as Figure 1a and Figure 1b shown, a series of parallel reinforcing elements 2 (here, T-beams) are first welded to the flat plate 1 to form a reinforced flat plate 3. Additionally, a series of parallel second reinforcing elements 4 (also T-beams here) can be welded perpendicular to the first reinforcing elements 2 to the flat plate 1 to form the reinforced flat plate 3. Then the reinforced flat plate 3 is passed through a bending machine 50 to form a reinforced cylindrical pipe section 10.

[0160] In an eleventh example, as Figure 16 shown, the reinforcing elements 2 form a circular cross-section on the outer surface area of the formed reinforced cylindrical pipe section 10.

[0161] The advantage of having the reinforcing elements 2 on the outer surface area of the formed reinforced cylindrical pipe section 10 is that a second metal plate can be bent independently and more easily welded to the reinforcing elements 2 to produce a double flatdeck (or double skin), which further strengthens the pipe section 10.

[0162] Twelfth Example

[0163] In a twelfth example, the reinforcing elements 2 are placed on the flat plate 1 without being welded initially. Then, the flat plate 1 and the reinforcing elements 2 are passed through a bending machine 50, and the bent reinforcing elements 2 can be welded later to the outer surface area of the bent metal plate 1.

[0164] Thirteenth Example

[0165] In a thirteenth example, a reinforced pipe section 10 is prepared as in the eleventh example or the twelfth example. After that, as Figure 15 shown, a second metal plate 5 is bent and then welded to the reinforcing elements 2 formed on the outer surface area of the reinforced cylindrical pipe section 10 to form a double layer (or double skin).

[0166] Fourteenth Example

[0167] In a first step, as Figure 1a and Figure 1bAs shown, first, a series of parallel reinforcing elements 2 (here, T-shaped beams) are welded to the flat plate 1 to form the reinforced flat plate 3. Additionally, a series of parallel second reinforcing elements 4 (also T-shaped beams here) can be welded perpendicular to the first reinforcing elements 2 to the flat plate 1 to form the reinforced flat plate 3. Then, the reinforced flat plate 3 is passed through a bending machine 50 to form a helically reinforced tube or helix 30. For example, a welding arm is used to weld the seam 20 of the helix 30 at the angle α of the bending line.

[0168] In the fourteenth example, the reinforcing elements 2 form a helix on the outer surface area of the formed helically reinforced tube or helix 30.

[0169] The advantage of having the reinforcing elements 2 on the outer surface area of the formed helically reinforced tube or helix 30 is that the second metal plate can be bent independently and is more easily welded to the reinforcing elements 2 to produce a double flat layer (or double shell layer), which further strengthens the helically reinforced tube or helix 30.

[0170] Fifteenth Example

[0171] Now referring to Figure 17 , in the fifteenth example, the flat plate 1 is passed through a bending machine 50 to form a helical tube or helix 30. Additionally, at least one reinforcing element 2 is independently manufactured or bent to form a complete circle, substantially complete circle, or helix, and is positioned on the outer surface area of the helical tube or helix 30. Then, after the flat plate 1 is bent at least 360 degrees using the bending machine 50, that is, starting from the second turn, at least one reinforcing element 2 is welded to the outer surface area of the first helix 30 to form the reinforced tube 10.

[0172] The advantage of having the reinforcing elements 2 on the outer surface area of the formed reinforced tube 10 is that the second metal plate 5 can be bent independently and is more easily welded to the reinforcing elements 2 to produce a double flat layer (or double shell layer), which further strengthens the reinforced tube 10.

[0173] Sixteenth Example

[0174] In the sixteenth example, a helically reinforced tube or helix 30 is prepared as in the fourteenth or fifteenth example. After that, the second metal plate 5 is bent and then welded to the reinforcing elements 2 formed on the outer surface area of the helically reinforced tube or helix 10 to form a double flat layer (or double shell layer).

[0175] Independently of the above examples, when at least two first metal reinforcing elements 2 are placed on the first metal plate 1, the at least two first metal reinforcing elements 2 are advantageously parallel, and the distance between the at least two first metal reinforcing elements 2 is between 1 / 50 and 1 / 2 of the bending diameter D of the tube section, preferably between 1 / 30 and 1 / 3 of the bending diameter D of the tube section.

[0176] In the same spirit, when at least one first metal reinforcing element 2 is helical, the pitch of the helix is between 1 / 50 and 1 / 2 of the bending diameter D of the tube section, preferably between 1 / 30 and 1 / 3 of the bending diameter D of the tube section.

[0177] These segments can then be assembled together and welded to form longer cylindrical or conical-cylindrical segments.

[0178] Those skilled in the art will understand that for the first and last parts of the reinforced tube 10, the metal plate can be cut before the bending operation so that the tube ends come out of the bending machine, without the need to cut the metal plate after the bending operation, in order to make the cylinder ends orthogonal to the longitudinal axis of the tube. This is particularly interesting when manufacturing the helically reinforced tube 10.

[0179] Bending machine

[0180] In Figure 6 and Figure 7 two examples of a bending machine 50 are shown. The bending machine 50 includes a pair of outer rollers 52 and an inner roller 51.

[0181] In the bending machine 50 of the present invention, the inner roller 51 is adapted to bend the reinforced bending plate 3 (i.e., the metal plate 1 welded to at least one first reinforcing element 2).

[0182] As Figure 6 (and Figure 7 ) shows, the inner roller 51 is not flat, but includes a cylinder (or conical cylinder) with at least one first groove 55 for receiving at least one first reinforcing element 2. The depth of the at least one first groove 55 is preferably equal to the height of the at least one first reinforcing element 2. In this way, the bending force applied by the inner roller 51 is distributed over the metal plate 1 and the at least one first reinforcing element 2, rather than only over the at least one first reinforcing element 2, thus reducing the risk of buckling of the at least one first reinforcing element 2.

[0183] The at least one first groove 55 is arranged on the circumference around the inner roller 51.

[0184] The inner roller 51 can be a solid piece, or alternatively it can be a cylinder covered by a series of disks.

[0185] It should be understood that when forming the reinforced tube section 10 with the reinforcing element 2 formed on its outer surface area, for example, in the above examples 11 to 16, at least one first groove 55 must be arranged on the outer roller 52 instead of the inner roller 51 to accommodate at least one first reinforcing element 2.

[0186] As Figure 7 shown, if the reinforcing plate 3 includes at least one first reinforcing element 2 and at least one second reinforcing element 4 perpendicular to at least one first reinforcing element 2, the inner cylinder 51 includes at least one first groove 55 for accommodating at least one first reinforcing element 2 and at least one second groove 56 for accommodating at least one second reinforcing element 4. The depth of at least one first groove 55 and the depth of at least one second groove 56 are preferably equal to the height of at least one first reinforcing element 2 and the height of at least one second reinforcing element 4 respectively. In this way, the bending force applied by the inner roller 51 is distributed on the metal plate 1, at least one first reinforcing element 2 and at least one second reinforcing element 4, rather than only on at least one first reinforcing element 2 and / or at least one second reinforcing element 4, thereby reducing the risk of buckling of at least one first reinforcing element 2 and / or at least one second reinforcing element 4.

[0187] At least one first groove 55 is arranged on the circumference around the inner cylinder (or tapered inner cylinder). At least one second groove 56 is arranged longitudinally along the outer surface of the inner roller 51.

[0188] The bending machine 50 can be advantageously mounted such that the central axis of the inner roller is orthogonal or parallel to the gravity axis.

[0189] It should be understood that when forming the reinforced tube section 10 with the reinforcing element 2 formed on its outer surface area, for example, in the above examples 11 to 16, at least one first groove 55 and at least one second groove 56 must be arranged on the outer roller 52 instead of the inner roller 51 to accommodate at least one first reinforcing element 2 and at least one second reinforcing element 4.

[0190] In the third example of the bending machine 50, as Figure 13 shown, the bending machine is arranged in the same manner as described in the example of the bending machine 50 above, but the inner roller 51 includes a series of inner rollers 61 and lateral rollers 62 arranged on the inner roller support arm 73. Each inner roller 61 is arranged at intervals along the bending line substantially parallel to the longitudinal axis of the helix 30 on the inner roller support arm 73. Each of the inner rollers 61 is also arranged on the inner roller support arm 73.

[0191] As Figure 13As shown, a lateral spacer including a lateral roller 62 is arranged on the inner roller 61 to support at least one first metal reinforcing element 2 during the plastic bending of the first metal reinforcing element 2. To ensure the stability of the roller, at least two lateral rollers 62 are arranged on each side of each inner roller 61.

[0192] It should be understood that when forming the reinforced tube section 10 with the reinforcing element 2 formed on its outer surface area, for example, in the above examples 11 to 16, it is the outer roller 52 that includes a series of outer rollers and lateral rollers arranged on the outer roller support arms.

[0193] When bending the metal sheet 1 and the reinforcing element 2, there is a risk that the reinforcing element may buckle. One way to reduce the buckling risk is to increase the width between the two outer rollers 52 in order to increase the effective bending arm, thereby reducing the force required for the rollers 51, 52 to plastically bend the sheet 1 and the reinforcing element 2.

[0194] In other words, in order to reduce the force applied to the sheet 1 welded with the reinforcing element 2, the space between the outer rollers 52 of the bending machine 50 can be increased.

[0195] Another alternative to reduce the buckling risk is to use at least two spacers 60. As Figure 8 and Figure 9 shown, the spacer is an object that can be placed on each side of at least one first reinforcing element 2 and between the first metal sheet 1 and the inner roller 51. Preferably, wherever the inner roller contacts the first metal sheet and at least one first reinforcing element, these at least two spacers 60 are along the bending line and even more preferably cover the width of the first metal sheet 1 on each side of the bending line.

[0196] Depending on the number of the first reinforcing elements 2 and their placement on the first metal sheet 1, there can be multiple spacers of different widths. In other words, the width of the spacer 60 is the distance between two reinforcing elements 2 or between the reinforcing element 2 and the side of the first metal sheet 1.

[0197] Preferably, it is intended that each of at least one first reinforcing element 2 is included between at least two spacers, so that the spacers will prevent buckling during the bending step c).

[0198] The at least two spacers 60 can be of any suitable shape complementary to the shape of at least one first reinforcing element 2, such that as Figure 8 and Figure 9 shown, the cross-section of the shape of the first reinforcing element 2 and the shape of the at least two spacers 60 can be substantially rectangular, having substantially the same width as the first metal sheet 1 and substantially the same height as at least one first reinforcing element 2.

[0199] In the case where at least one first reinforcing element 2 is a T-beam or a U-beam, at least two spacers 60 may be cuboids.

[0200] At least two spacers 60 may be freestanding. That is, they do not necessarily have to be attached to a support structure or the like.

[0201] Preferably, as Figure 10 and Figure 11 shown, at least two spacers 60 may include vertically acting spacer rollers 61 that transfer the pressure of the inner roller 51 to the first metal plate 1. In order to suppress the spacers 60 during the rolling / bending operation, spacer-suppressing supports 71 may be arranged in front of the inner roller 51 and the outer roller 52

[0202] Preferably, at least two spacers 60 may also include laterally acting spacer rollers 62 to prevent buckling of at least one first reinforcing element 2.

[0203] Each roller 61, 62 may be freely rolling or may have a motor driving them.

[0204] In the case where at least one first reinforcing element 2 is a T-beam, at least two spacers 60 should be designed to avoid buckling of all parts of the T-beam (i.e., both the shear-resistant web and the flange), as in the examples using (one or more) rollers ( Figure 9 、 Figure 10 or Figure 11 ) or cuboids ( Figure 8 ) as described above.

[0205] It should be understood that when forming the reinforcing tube section 10 that forms the reinforcing element 2 on its outer surface region, for example, in the above examples 11 to 16, at least two spacers 60 are preferably placed on each side of at least one first reinforcing element 2 and between the first metal plate 1 and the outer roller 52.

[0206] The bending machine 50 is not always able to apply a bending moment to the ends of the article to be bent, so it is not possible to permanently and plastically bend those ends. Due to this difficulty, the ends of the metal plate 1 are usually not bent when bending the plate 1 and the reinforcing element 2. Usually, the non-bent end portions of the plate 1 are cut off before being welded together to form a tube such as a cylinder.

[0207] To further improve the method, one or both end portions of the plate may be bent in a first step before placing the reinforcing element 2 on the metal plate 1. Additionally, at least one reinforcing element 2 may be shaped or cut at one or both end portions such that at least one reinforcing element 2 can be easily placed on the plate 1 (with one or both bent end portions).

[0208] Thus, the metal sheet 1 has end portions in the shape of skate tips which do not need to be plastically bent to become part of the final circular or substantially circular shape of the produced tube cross-section because they have substantially the same curvature.

Claims

1. A bending machine (50) for manufacturing a reinforced tube or tube section (10), said reinforced tube or tube section (10) comprising a metal tube or tube section having a bottom with a thickness t and a diameter D, and at least one first metal reinforcing element (2) located on the inner or outer surface along the circumference of said metal tube or tube section (10). Wherein said bending machine (50) comprises an inner roll (51) and two outer rolls (52), and wherein the outer surface of said inner roll (51) or said outer roll (52) comprises at least one first groove (55) for receiving at least one first metal reinforcing element (2).

2. The bending machine (50) according to claim 1, wherein the ratio D / t is at least 100.

3. The bending machine (50) according to claim 1 or 2, wherein the depth of said at least one first groove (55) is at least equal to the height of said at least one first metal reinforcing element (2).

4. The bending machine (50) according to any one of the preceding claims, wherein the depth of said at least one first groove (55) is substantially equal to the height of said at least one first metal reinforcing element (2).

5. The bending machine (50) according to any one of the preceding claims, further comprising means for welding said at least one first metal reinforcing element (2) to the metal tube section, such as welding arms.

6. The bending machine (50) according to any one of the preceding claims, further comprising at least two spacers (60).

7. The bending machine (50) according to any one of the preceding claims, wherein each spacer comprises a vertically acting spacer roll (61).

8. The bending machine (50) according to any one of the preceding claims, wherein each spacer comprises at least one laterally acting spacer roll (62).

9. The bending machine (50) according to any one of the preceding claims, further comprising support rolls (70).

10. The bending machine (50) according to any one of the preceding claims, wherein during operation of said bending machine (50), the orientation of said inner roll (61) and said outer roll (62) can be adjusted relative to the longitudinal axis of the reinforced tube (10).

11. The bending machine (50) according to any one of the preceding claims, wherein said first groove (55) is a helical groove.

12. The bending machine (50) according to any one of the preceding claims, wherein said inner roll (51) comprises a series of inner rolls (61) and lateral rolls (62) arranged on an inner roll support arm (73), or wherein said outer roll (52) comprises a series of outer rolls and lateral rolls arranged on an outer roll support arm.

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