EP4259355A1

EP4259355A1 - Arrangement, method and straightening unit for roll bending of the end region with the two ends of sharply bent tubes using a three-roll bending machine

Info

Publication number: EP4259355A1
Application number: EP21839043.3A
Authority: EP
Inventors: Dieter Kapp
Original assignee: Theodor Graebener GmbH and Co KG
Current assignee: Theodor Graebener GmbH and Co KG
Priority date: 2020-12-14
Filing date: 2021-12-09
Publication date: 2023-10-18
Also published as: DE102020133419B4; DE102020133419A1; WO2022128734A1

Abstract

The invention relates to an arrangement, a method and a straightening unit (18) for roll bending of the connecting region with the ends (28a, 28b) of sharply bent tubes together using a three-roll bending machine (10). An arrangement according to the invention for roll bending of the connecting region with the ends (28a, 28b) of sharply bent tubes (30) using a three-roll bending machine (10) comprises: a) a three-roll bending machine (10) with a height-adjustable upper roll (16), a straightening element (32) and two lower rolls (12, 14), b) a straightening unit (18) with a height-adjustable ram (24) which is arranged so as to extend through a clearance between the lower rolls (12, 14), and c) a measuring device (46) for determining the radius of a tube (30), arranged in the three-roll bending machine (10), at least in a tube section which extends between bearing points (A1, A2) of the tube on the two lower rolls (12, 14).

Description

Arrangement, method and straightening unit for bending the end area with the two ends of pointed-bent tubes with a 3-roller bending machine

description

The invention relates to an arrangement, a method and a straightening unit for round-bending the end area with the two ends of pipes bent to a point with a 3-roll bending machine, in particular using the top roll of a 3-roll bending machine. In this context, pointed-bent tubes are understood to mean tubes that are made from a bent sheet of metal that is rounded over a large part of the circumference with an approximately constant radius, but which is bent on both sides of the joint at which the open ends of the sheet are connected to one another (e.g welded), has a connection area that is still unbent or has only a small, insufficient curvature, which encompasses the two ends.

In particular, the invention relates to 3-roll bending machines which are suitable for bending pipes with a large diameter and with which, according to the prior art, only pointed-bent pipes can be produced. In particular, reference is made in this context to 3-roll bending machines, which are used, for example, for the production of offshore pipes, in boiler construction and in general apparatus construction. According to the state of the art, such pipes are often further processed as pointed-bent pipes and installed and used at their places of use. Alternatively, it is known from practice to produce such tubes completely round with a 4-roller bending machine. However, the 4-roller bending machines are significantly more expensive to purchase (investment costs). Such pipes usually have diameters between 4 m and 12 m, ie radii that vary between 2 m and 6 m. The usual wall thicknesses of such pipes are between 100 mm and 200 mm. The lengths of such pipes are usually a maximum of 5 m, in particular between 1 m and 4.5 m. Steel is used in particular as the material, which is not only available relatively inexpensively, but is also easy to process further, in particular by welding, for example around which To connect longitudinal joint extending longitudinally of the pipe after the bending process and/or to connect several pipes to one long pipe. In practice, however, any other or more special materials are also used, in particular composite materials and stainless steel.

The object of the invention is to increase the usability of a 3-roller bending machine by providing an arrangement, a method and a straightening unit that enable the production of a high-quality tube geometry using the top roller of a 3-roller bending machine . In particular, with the invention, it should be possible to round bend the pointed ends of a tube that was produced with a 3-roll bending machine and whose joint between the ends has already been connected, in particular by welding.

The object is achieved according to the invention with the features of the independent claims. Further advantages and practical embodiments of the invention are described in connection with the dependent claims.

An arrangement according to the invention for round bending the connection area with the ends of pointed-bent tubes with a 3-roll bending machine a) a 3-roller bending machine with a height-adjustable upper roller, a straightening element and two lower rollers, b) a straightening unit with (at least) one height-adjustable punch, which is arranged to project through a free space between the lower rollers, and c) a measuring device for determining the radius of a tube arranged in the 3-roller bending machine, at least in a tube section which extends between the support points of the tube on the two lower rolls.

Such an arrangement makes it possible to position a pointed-bent tube on the bottom rolls in such a way that the abutting side is oriented downwards and is located between the bottom rolls. Preferably, the distance between the lower rollers is adjustable and is set relative to one another in such a way that the pointed-bent section is completely visible and accessible from the underside. In this case, the pointed-bent end can be bent round within the 3-roll bending machine through the interaction of the upper roll with the at least one straightening element, the straightening unit and the measuring device. This can be done manually, semi-automatically or fully automatically by bringing about a bend by moving the top roller relative to one another with the straightening element onto the ram of the straightening unit and measuring the resulting curvature with the aid of the measuring device. The approaching one another can be achieved by moving the top roller with the straightening element in the direction of the ram (in particular downwards), by moving the ram of the straightening unit in the direction of the top roller with the straightening element, or by a combination of these two movements. In this respect it is both possible to use the top roller with the straightening element as an abutment and to use the stamp as an abutment. In a practical embodiment, it can be provided that the ram—with or without an associated lifting unit—is arranged such that it can be folded, moved or otherwise temporarily removed, in particular around the area between the two lower rollers and/or a crossbeam to which the ram is attached to be able to use it temporarily for other purposes.

The two bottom rolls of a 3-roll bending machine are usually mounted in separate bearing stands, which support shafts or axles of the bottom rolls. The straightening unit is preferably designed in such a way that it can be positioned between the corresponding bearing stands.

In a practical embodiment of an arrangement according to the invention, the measuring device is an optical measuring device and/or the measuring device is arranged to interact with the straightening unit and/or the top roller.

A laser measuring device is particularly suitable as an optical measuring device, preferably a laser measuring device with which a large number of measuring beams can be emitted simultaneously or sequentially at a very short cycle rate in order to determine the curvature and in particular the radius of a surface from the measured distances. It is additionally pointed out that other measuring devices can also be used or can be used as an alternative, in particular wave-based measuring devices, such as ultrasonic measuring devices.

A cooperating arrangement of measuring device and straightening unit means in particular that the measuring device and the straightening unit and/or the measuring device and the top roller are coupled to one another - for example by means of a controller - in such a way that, based on measured values from the measuring device, control commands are sent to the straightening unit and/or can be sent to the top roller, for example to move or control the punch and/or the top roller in a targeted manner in such a way that a radius within a target tolerance is achieved.

In a further practical embodiment of an arrangement according to the invention, the straightening unit has a traversing unit that can be moved in at least one horizontal direction. For example, a possibility of movement in an axial direction of the rollers can be provided, i.e. parallel to the axes of rotation of the lower rollers and the upper roller. Such mobility is particularly advantageous when the stamp of a straightening unit is to be used several times at different positions for processing a pipe, without the pipe to be processed and the 3-roller bending machine having to be moved. A corresponding displacement unit can be implemented in particular by means of a carrier designed as a carriage, which is arranged on a suitable frame so that it can be displaced. Such a carriage can be designed to slide or have roller bearings. Due to the lower friction, roller bearings are preferred, in particular by means of rollers.

Alternatively or in addition to a traversing unit, several height-adjustable stamps and several measuring devices can also be provided. As a result, a traversing unit can be dispensed with entirely if a sufficient number of height-adjustable stamps with measuring devices assigned to the stamps are provided over the length of a pipe to be processed. In this case, a punch can be provided, for example at a distance of 500 mm from each other, in order to roundly bend a tube with pointed ends and with a length of several meters over the entire length in the area of the pointed ends.

Reference is also made to the possibility of providing only one punch of sufficient length to allow the tube to be bent to be bent over a sufficiently long length so that, at the end of the machining, it is rounded over its entire length. The invention also relates to a method for round bending the connection area with the ends of pointed-bent pipes, in which a pipe with the pointed-bent ends oriented downwards is arranged between the upper roller and the two lower rollers of a 3-roll bending machine, with between the upper roller and the pipe at least one straightening element is positioned and wherein a) using a straightening unit with at least one height-adjustable stamp, which is arranged to project through a free space between the bottom rollers, the distance between the straightening element and the stamp is reduced in order to bend the ends - by applying force - and b) the radius of the ends produced by bending is determined using a measuring device.

Reference is hereby once again made to the advantages already described above in connection with the arrangement and optional further technical features of the arrangement, which can also be implemented in connection with the implementation of the method.

In a further practical embodiment of the method according to the invention, steps a) and b) are repeated one after the other until the radius determined by means of the measuring device is within a desired value range. For example, a target value range for the radius between 4.01 m and 3.99 m can be specified in order to then repeat steps a) and b) until a radius in the target value range is reached for the first time . If during an application of the method it is found that the target value range is first exceeded and then fallen below, the target value range has been missed. It is then advisable to adapt the procedure for processing other identical tubes by increasing the force in smaller ones discrete steps and/or the setpoint range is selected to be larger.

In a further practical embodiment of the method according to the invention, the straightening unit is designed to be movable in the longitudinal direction of the tube to be bent, and the method is repeated several times in order to bend the ends in the area of different length sections. This embodiment has already been described above in connection with a traversing unit, which is realized in particular by means of a traversing carriage. It is particularly suitable in connection with a - compared to the 3-roller bending machine - compact straightening unit with a traversing unit and at least one stamp, which has a significantly shorter length than the upper roller and the two lower rollers.

It is further preferred if, in a method according to the invention, the radius is also determined with the measuring device while the ends of a tube are being bent. It is necessary to select a suitable measuring device and to align it and position it relative to the other elements of an arrangement according to the invention in such a way that the measuring device can determine and process a sufficient number of measured values even during bending so that the radius can be determined. In this case, by simultaneously measuring and readjusting the punch or the top roller with the straightening element, the sharp-bent ends of a pipe can be bent quickly and precisely, in particular by continuously increasing the bending force until the measured radius is within a target value range.

Protection is also claimed for a straightening unit for rounding the connection area with the ends of pointed-bent pipes together with a 3-roller bending machine, in particular with the top roller of such a 3-roller bending machine, the straightening unit having a height-adjustable stamp and at least one measuring device for determining the Has radius of the tube in an effective range of the stamp. This means that the measuring device must be designed and arranged in such a way that it is directed towards a surface of a pointed end to be machined, which changes its curvature under the influence of an effective surface of the punch. This can be done in particular by arranging the active surface and the stamp in the same orientation on the straightening unit in such a way that the stamp and the measuring device can be used at the same time. As already mentioned, a laser measuring device is particularly suitable as a measuring device, which can emit measuring beams, in particular a fan-shaped bundle of rays, and determine the distance and a resulting geometry, in particular radii.

In a practical embodiment of a straightening unit according to the invention, the measuring device has a laser measuring device and/or the stamp is functionally coupled to a traversing unit, by means of which the stamp—in addition to a vertical direction—is also slidably mounted perpendicular to the vertical direction. Reference is hereby once again made to the associated advantages, in particular in connection with a carrier designed as a carriage, which have already been mentioned above.

Further practical embodiments and advantages of the invention are described below in connection with the drawings. Show it:

Fig. 1 shows an arrangement with a 3-roller bending machine and a straightening unit before the forming of the connection area with the two ends of a pointed-shaped pipe and

FIG. 2 shows the arrangement from FIG. 1 during or at the end of a reshaping of the connection area with the two ends of the pipe. Figures 1 and 2 show an arrangement according to the invention with a 3-roller bending machine 10, of which a first bottom roll 12, a second bottom roll 14 and the lower part of a top roll 16 are shown. As can be seen from FIG. 1, the two lower rollers 12, 14 are arranged symmetrically in relation to the upper roller 16. In this respect, the upper roller is arranged centrally above the two lower rollers 12, 14, and the lower rollers both have the same diameter. In the embodiment shown, the diameter of the lower rollers is between 500 and 1,500 mm, in particular 1060 mm. The diameter of the top roller 16 is larger and is between 900 mm and 2,000 mm, in particular around 1,320 mm.

It is made clear that a symmetrical arrangement is not required for the implementation of the invention.

The arrangement also includes a straightening unit 18 which is arranged between the two bottom rollers 12, 14 viewed in the horizontal direction. The straightening unit 18 essentially comprises a frame 20 and a lifting unit 22 with a stamp 24 which is designed to be movable in the direction of the double arrow 26 (here: in the vertical direction).

FIG. 1 shows the punch 24 in a lower position before a bending process, ie the contact surface 36 of the punch 24 is not in contact with the outside A of a tube 30 that is still to be bent, of which only the lower section is shown. As can be seen from FIG. 1, the tube 30 is still unbent over a certain length, starting from the two ends 28a, 28b. Nevertheless, the ends 28a, 28b are connected to one another in the area of the inside I by welding. This results in a gap in the area of the outside A of the ends 28a, 28b. The aim of the bending process is to bend the unbent end sections, which extend in an area between the two support points A1, A2 of the tube 30 on the lower rollers 12, 14 to the ends 28a, 28b, to bend in such a way that the radius is approximately the same as that of the remaining outer surface A of the tube 30.

The stamp 24 is shown in FIGS. 1 and 2 as a rectangle only as an example. The stamp 24 has a contact surface 36 which at least partially makes contact with the outside of the tube 30 during the bending process. In contrast to what is shown in the figures, the contact surface 36 can also have any other desired shape, in particular a curved shape.

A straightening element 32 is arranged between the top roller 16 and the inside I of the tube 30 . The aligning element 32 has an approximately rectangular cross-sectional shape and a groove-like recess 34 oriented inwards in cross-section. This results in two contact areas K1, K2 between the straightening element 32 and the inside I of the pipe 30.

The frame of the straightening unit 20 is formed by a carrier 38 with a rectangular cross section, on which a cross member 40 is mounted. The carrier 38 is fastened in two bearing stands, not shown in the figures, which form the basis for the bearing of all the rolls 12, 14, 16. The cross member 40 is U-shaped and is mounted on rollers 42 perpendicular to the plane of the drawing so that it can be moved relative to the carrier 38 in the manner of a carriage. A drive unit 44 is arranged on the crossbeam 40, which provides both a drive for moving the crossbeam 40 relative to the beam 38 and a drive for moving the ram 24 in the direction of the double arrow 26. The combination of the crossbeam 40 and the drive unit 44 can be regarded as a traversing unit insofar as it enables the stamp 24 to be moved perpendicularly to the plane of the drawing.

A measuring device 46 in the form of a laser measuring device, which is shown only schematically as a rectangle, is arranged on stamp 24 . With the measuring device 46, distances and the resulting curvature or the respective radius of the outside A of the pipe 30 can be detected within a fan-shaped measuring area 48, represented by a dashed trapezoid. The measuring device 46 is arranged in such a way that the curvature of the outside can also be recorded while the stamp 24 is acting on the pipe 30 .

Figure 2 shows the stamp 24 in an upper position with contact to the outside A of the two ends 28a, 28b of the already bent tube 30. As can be seen, the bending process is already complete because on the outside A of the tube 30 there is a contour with a constant radius is formed, which also extends over the connection area between the support points A1, A2. As a result, the connection area of the pointed-bent tube according to FIG. Both the straightening element 32 with the top roller 16 and the stamp 24 of the straightening unit 18 can serve as counter bearings when the bending forces are applied.

The measuring device is preferably used—at least then—when a bending force is no longer acting on a pipe 30 that is located in the 3-roller bending machine 10 and is subjected to a bending force. In practice, therefore, in most cases an iterative procedure is necessary in order to achieve a target value range for a radius in the area of the outside A of a tube 30, in which bending processes and measurements alternate. If a target value range is reached, the bending process can be completed and the punch 24 of the straightening unit 18 can be lowered. If the pipe 30 is to be processed at several points by the straightening unit 18, the ram 24 is moved by the traversing unit to the next point of use after the target value range has been reached, and the process is then repeated there in the same way. The features of the invention disclosed in the present description, in the drawings and in the claims can be essential both individually and in any combination for the realization of the invention in its various embodiments. The invention is not limited to the embodiments described. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

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Reference List

10 3-roller bending machine

12 bottom roller (first)

14 bottom roller (second)

16 top roller

18 straightening unit

20 frame

22 lifting unit

24 stamps

26 double arrow

28a, 28b end

30 pipe

32 directional element

34 recess

36 contact surface

38 carriers

40 crossbars

42 roll

44 drive unit

46 measuring device

48 measuring range

A outside

A1, A2 support point

I inside

K1, K2 contact area

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Claims

patent claims

1. Arrangement for round bending the connection area with the ends (28a, 28b) of pointed-bent pipes with a 3-roller bending machine (10), comprising a) a 3-roller bending machine (10) with a height-adjustable upper roller (16), a straightening element (32) and two lower rollers (12, 14), b) a straightening unit (18) with a height-adjustable ram (24) which is arranged to project through a free space between the lower rollers (12, 14) and c) a measuring device (46) for Determination of the radius of a tube (30) arranged in the 3-roll bending machine (10), at least in a tube section which extends between support points (A1, A2) of the tube on the two bottom rolls (12, 14).

2. Arrangement according to the preceding claim, characterized in that the measuring device (46) is an optical measuring device (46).

3. Arrangement according to one of the preceding claims, characterized in that the measuring device (46) is arranged to interact with the straightening unit (18) and/or the top roller (16).

4. Arrangement according to one of the preceding claims, characterized in that the straightening unit (18) in at least one high has rizontal direction movable traversing unit. . Arrangement according to one of the preceding claims, characterized in that several height-adjustable stamps (24) and several measuring devices (46) are provided. . Method for round bending the connection area with the ends of pointed-bent tubes (30), in which a pointed-bent tube (30) with the connecting area and the ends (28a, 28b) oriented downwards between the upper roller (16) and the lower rollers (12, 14) of a 3-roller bending machine, with at least one straightening element (32) being positioned between the top roller (16) and the tube (30), characterized in that a) using a straightening unit (18) with a height-adjustable stamp (24 ), which is arranged to penetrate a clearance between the lower rollers (12, 14), the distance between the straightening element (18) and the punch (24) is reduced in order to bend the ends and b) the radius produced by the bending in the Connection area with the ends (28a, 28b) is determined by means of a measuring device (46).

7. The method according to the preceding claim, characterized in that steps a) and b) are repeated one after the other until the radius determined by means of the measuring device (46) lies within a desired value range. - 16 - Method according to one of the two preceding claims, characterized in that the straightening unit (18) is designed to be movable in the longitudinal direction of the pipe (30) to be bent and the method is repeated several times in order to separate the connection area with the ends (28a, 28b) to bend in the area of different length sections. Method according to one of the three preceding claims, characterized in that the radius is determined with the measuring device (46) during the bending of the connection area with the ends (28a, 28b). Straightening unit for rounding the connection area with the ends (28a, 28b) of pointed-bent pipes (30) together with the top roller (16) of a 3-roller bending machine (10), the straightening unit (18) having a height-adjustable stamp (24) and at least one Measuring device (46) for determining the radius of the tube (30) in an effective range of the stamp (24). Straightening unit according to the preceding claim, characterized in that the measuring device (46) has a laser measuring device. Straightening unit according to one of the two preceding claims, characterized in that the ram (24) is functionally coupled to a traversing unit, by means of which the ram (24) is mounted so as to be displaceable perpendicularly to the vertical direction.

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