DE102019211936A1 - Screw seam tube and method for producing a screw seam tube - Google Patents

Abstract

The invention relates to a screw seam tube (2) comprising at least one cylindrical tube section, which consists of an integrally formed, helically curved metal strip (n + x) welded to a continuous screw seam line (3), which has a wall thickness that varies over its length. The invention also relates to a method for producing a cylindrical screw seam tube (2), in which at least one metal band (n + x) is deformed helically to form a slotted tube by means of at least one bending device and the metal band (n + x) at the band edges brought together at the screw seam line is welded and a metal band with a wall thickness that varies over its length is used as the metal band (n + x).

Description

The invention relates to a screw seam tube made of a helically bent sheet metal, which is welded to a screw seam line.

The invention further relates to a method for producing a screw seam tube and the use of a screw seam tube for producing a tower structure.

In certain structures, such as the tower structures of wind power generators, it is common to design their diameters in accordance with the bending moment curve of an expected load. Tower structures of wind power generators usually consist of several segments, which are composed of several pipe sections. The pipe sections are usually screwed together on flange connections.

The individual segments or pipe sections are manufactured in one plant and assembled on site to form a tower structure. The wall thickness of the individual pipe sections is designed according to the expected loads. This means that, for example, the segments or pipe sections in the area of the tower base have a correspondingly large diameter and a large wall thickness, while the segments or pipe sections to be arranged further above have a smaller diameter and also a smaller wall thickness. The size of the segments to be used is often limited by the required transportation to the construction site. It is also often desirable to optimize the wall thickness and geometry of individual segments with regard to the expected bending stress.

It is known in the prior art to assemble structures for accommodating wind power generators from conical, spirally welded segments. From the US 8,720,153 B2 For example, a method for producing a tapered conical structure from spirally welded metal sheets is known, the basic shape of the cone being obtained by first graphically cutting open the shape of the cone and unwinding it into the plane. The edge lines of one or more strips are then drawn on the trapezoid thus obtained. Correspondingly cut sheets are then wound into a conical structure with a helical seam line and welded together along the resulting seam line. This process is complex and complicated.

From the US 2018/0193893 A1 a method for producing a cylindrical screw seam tube with a wall thickness varying over its length is known. In this method, a plurality of sheets of different wall thicknesses are welded to form a strip or a band, which is bent in a helical manner into a slot tube by means of a bending device and which is welded along a continuous screw seam line. The process requires the provision of a large number of sheets with different wall thicknesses. In addition, a screw seam tube produced in this way comprises a plurality of transverse weld seams which form lines of weakness or notch lines of the tube. Due to the fact that as a rule a different wall thickness is used for each cycle, there are also material leaps that must be taken into account when calculating the resulting structure.

The invention is therefore based on the object of avoiding the disadvantages mentioned above, in particular of providing a screw seam tube which can be produced in a relatively simple manner with a wall thickness distribution adapted to the expected load.

The invention is also based on the object of providing a method for producing such a screw seam tube. Finally, the invention is based on the object of making it possible to manufacture a structure using screw seam tubes which is structurally adapted in a simple manner to the bending line to be expected.

The object is achieved with the features of independent claims 1, 7 and 12. Advantageous refinements of the invention result from the subclaims.

According to the invention, a screw seam tube is provided, which comprises at least one cylindrical tube section, which consists of a one-piece, helically curved metal band which is welded to a screw seam line and has a wall thickness which varies over its length.

In this way, cross welds in particular are largely avoided. So-called coil strips obtained by hot rolling in a rolling mill can preferably be used as metal strips. Such metal strips can be provided relatively easily with a diameter varying over their length or with a wall thickness varying over their length.

The screw seam tube according to the invention is preferably composed of a multiplicity of cylindrical tube sections which are in each case joined together at the ends. The individual pipe sections can be welded together, for example.

The wall thickness of the metal strip of at least one pipe section can vary continuously or discontinuously over its length.

The wall thickness of the metal strip can, for example, be relatively large at a first end and relatively small at a second end. The wall thickness of the metal strip can decrease continuously over a first section of the metal strip from a first end of the metal strip to, for example, approximately the middle of the metal strip. In this case, for example, the wall thickness can remain constant from approximately the center of the metal strip to a second end of the metal strip. The ratio of the length of the relevant sections of the metal strip to one another is not critical to the invention. In the aforementioned example, the first section of the metal strip extends from a first end of the metal strip to approximately the middle. However, this section can, for example, only extend over a third or a quarter or over a three-fourths or over any other fraction of the length of the metal strip.

Alternatively, it can be provided that the metal strip has at least two sections with different constant wall thicknesses.

In principle, it can be advantageous if the wall thickness of the metal strip varies at least one pipe section over its entire length or over any partial length.

In an advantageous and expedient variant of the screw seam tube according to the invention, it is provided that a first metal band of a first pipe section is connected by means of a cross weld seam to a second metal band of a second pipe section and that the first metal band and the second metal band in the area of their connection by means of the cross weld seam have the same wall thickness.

The outer diameter or the inner diameter of at least one cylindrical tube section is expediently constant.

According to the invention, a method for producing a cylindrical screw seam tube, in particular for producing a screw seam tube with one of the features described above, is provided, in which at least one metal strip is helically deformed into a slotted tube by means of at least one bending device and the metal strip is welded to the band edges brought together at the screw seam line , a metal strip with a wall thickness varying over the length of the metal strip being used as the metal strip.

Bending devices or deformation units for producing a slotted tube according to the invention are basically known in the prior art, for example from US 2018/0193893 A1 .

The metal strip can be welded in one or more stages. In an advantageous variant of the method according to the invention, it is provided that the band edges are welded in several steps, in a first step the band edges are initially only tacked and in a second step finish welding is carried out by laying a continuous spiral weld seam.

A metal strip which is obtained by rolling, preferably by hot rolling, is expediently used as the metal strip. The wall thickness of the metal strip can vary over the entire length or over a partial length.

In a preferred variant of the method according to the invention it is provided that in each case a metal strip with a wall thickness varying over its length and a further metal strip with a wall thickness varying over its length or a metal strip with a wall thickness varying over its length and a metal strip with a End wall of constant wall thickness are welded to one another at the ends, the metal strips each forming tube sections which have a nominally the same wall thickness at the ends to be welded.

Using coil strips with a discontinuous wall thickness, screw seam tubes can be produced in a particularly simple manner according to the previously described method, which are particularly suitable for the production of material-optimized cylindrical tubes / towers. For example, the screw seam tubes according to the invention can be used to manufacture tower structures for wind power generators.

• 1 zwei gewalzte Metallbänder mit jeweils einer über deren Länge variierenden Wandstärke zeigt,
• 2 einen ersten Abschnitt eines Schraubennahtrohrs gemäß der Erfindung zeigt,
• 3 einen zweiten Abschnitt eines Schraubennahtrohrs gemäß der Erfindung zeigt und
• 4 einen Längsschnitt durch einen Abschnitt eines Schraubennahtrohrs gemäß der Erfindung zeigt.

The invention is explained below with reference to the accompanying drawings, in which:

• 1 shows two rolled metal strips, each with a wall thickness varying along their length,
• 2nd shows a first section of a screw seam tube according to the invention,
• 3rd shows a second section of a screw seam tube according to the invention and
• 4th a longitudinal section through a portion of a screw seam tube according to the invention.

Reference is first made to 1 . The 1 shows a first type of metal band 1a and a second type of metal band 1b each obtained by hot rolling.

The first type of metal tape 1a has a first end with a wall thickness t1 and a second end with a wall thickness t2. The wall thickness or thickness of the first metal strip 1a decreases continuously from the first end from the wall thickness t1 to the wall thickness t2 at the second end.

The second type of metal tape 1b has a first end with a wall thickness t1 and a second end with a wall thickness t2. The wall thickness or thickness of the second type of metal strip 1b decreases discontinuously from the first end from the wall thickness t1 to the wall thickness t2 at the second end. In the 1 First partial length of the second type of metal strip shown on the left 1b has a continuously relatively larger wall thickness t1 up to approximately the center thereof, while the second partial length from approximately the center to the second end has a relatively small wall thickness t2.

According to the process for producing the example in the 2nd to 4th shown screw seam tube 2nd become metal bands of the type 1a and or 1b according to 1 deformed helically into a slotted tube by means of a bending device. The type of metal strip in question 1a , 1b is along the at a screw line 3rd merged band edges 4th welded.

This in 2nd screw seam tube shown 2nd comprises a first metal strip in the section shown n , a second metal band n + 1 and a third metal band n + 2 , each end forming a cross weld 5 are put together. Each of the metal bands n , n + 1 , n + 2 forms a tube section of the screw seam tube 2nd .

Each of the metal bands n , n + 1 , n + 2 can be of the first type 1a or as a metal band of the second type 1b be trained. The second metal band n + 1 has at its left end the same wall thickness t1 as the first metal band n at its right end. The second metal band n + 1 has at its right end the same wall thickness t2 as the third metal band n + 2 .

3rd shows a further section of the screw seam tube 2nd that is at the right end of the in 2nd screw tube shown 2nd and the third metal band n + 2 and a fourth metal band n + 3 and a fifth metal band n + 4 includes. The third metal band n + 2 has a constant wall thickness t2. The fourth metal band n + 3 has wall thickness t2 at its left end and wall thickness t1 at its right end. This is followed by the fifth metal band n + 4 which has the wall thickness t1 at its left end. Different from the section of the seam tube 2nd according to 2nd is the alignment of the fourth metal band n + 3 opposite to the orientation of the second metal band n + 1 .

4th shows a longitudinal section through a screw seam tube 2nd , in which the wall thickness of the metal strip n + x continuously changed. In this case, the wall thickness decreases continuously from left to right.

Reference list

1 a

first type metal band

1b

second type of metal band

t1

first wall thickness

t2

second wall thickness

2nd

Screw seam tube

3rd

Screw line

4th

Band edge

5

Cross weld

n

first metal band

n + 1

second metal band

n + 2

third metal band

n + 3

fourth metal band

n + 4

fifth metal band

n + x

any metal band

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 8720153 B2 [0005]
• US 2018/0193893 A1 [0006, 0020]

Claims (12)

Screw seam tube (2) comprising at least one cylindrical tube section, which consists of an integrally formed, helically bent and welded to a continuous screw seam line (3) metal strip (n + x), which has a wall thickness varying over its length. Screw seam tube after Claim 1 , characterized in that the wall thickness of the metal strip (n + x) of at least one tube section varies continuously over its length. Seam tube according to one of the Claims 1 or 2nd , characterized in that the wall thickness of the metal strip (n + x) of at least one tube section varies discontinuously over its length. Seam tube according to one of the Claims 1 to 3rd , characterized in that the wall thickness of the metal strip (n + x) of at least one tube section varies over its entire length or over a partial length. Seam tube according to one of the Claims 1 to 4th , characterized in that a first metal band (s) of a first pipe section is connected by means of a cross weld (5) to a second metal band (n + 1) of a second pipe section and that the first metal band (s) and the second metal band (n + 1 ) have the same wall thickness in the area of their connection to the cross weld seam (5). Seam tube according to one of the Claims 1 to 5 , characterized in that the inner diameter or the outer diameter of at least one cylindrical tube section is constant. Method for producing a cylindrical seam tube (2), in particular for producing a seam tube (2) with one of the features of one of the Claims 1 to 6 , in which at least one metal strip (n + x) is deformed helically into a slotted tube by means of at least one bending device and the metal strip (n + x) is welded to the strip edges (4) brought together at the screw seam line (3), the metal strip (n + x) a metal band with a wall thickness varying along its length is used. Procedure according to Claim 7 , characterized in that the band edges (4) are welded in several steps, the band edges (4) being connected with a tack weld in a first step and a final weld being carried out in a second step. Procedure according to one of the Claims 7 or 8th , characterized in that a metal strip is used as the metal strip (n + x), which was obtained by rolling, preferably by hot rolling. Procedure according to one of the Claims 7 to 9 , characterized in that the wall thickness of the metal strip (n + x) varies over the entire length or over a partial length. Procedure according to one of the Claims 7 to 10th , characterized in that in each case a metal band (n + x) with a wall thickness varying over its length and a further metal band (n + x) with a wall thickness varying over its length or a metal band (n + x) with a length over its length varying wall thickness and a metal strip (n + x) with a wall thickness which is constant over its length are welded to one another at the ends, the metal strips (n + x) each forming pipe sections which have a nominally the same wall thickness at the ends to be welded. Use of a screw seam tube (2) according to one of the Claims 1 to 6 for the manufacture of a tower structure to accommodate a wind power generator.

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