METHOD FOR FORMING A TUBULAR BODY, UNDULATING TUBULAR BODY AND USE OF SAME

Abstract

A method for forming a tubular body, comprising the following steps: making available a tubular body having a first and a second tube end, filling the tubular body with a liquid, closing the tubular body, and forming the tubular body.

Claims

1. A method for forming a tubular body, the method comprising: filling a tubular body with a liquid, the tubular body having a first end, a second tube end, and a cross-sectional shape; closing the tubular body, and forming the tubular body, wherein forming the tubular body includes changing the cross-sectional shape of at least a portion of the tubular body.

2. The method according to claim 1, comprising pressurizing the liquid in the tubular body before forming the tubular body.

3. The method according to claim 2, wherein the liquid is subjected to a pressure of 20 bar or more.

4. The method according to claim 1, wherein forming comprises introducing one or more bending radii into the tubular body.

5. The method according to claim 4, wherein the one or more bending radii is less than three times a diameter of the tubular body.

6. (canceled)

7. The method according to claim 1, wherein changing the cross-sectional shape includes placing the tubular body in a die and forming the tubular body to match the die by applying force to the tubular body.

8. The method according to claim 1 further comprises: bending the tubular body into a meandering shape, wherein the meandering shape has one or more substantially uncurved tube segments, each of the one or more substantially uncurved tube segments adjoin one or more of the bending radii.

9. The method according to claim 1, comprising: discharging the liquid from the tubular body when the pressure exceeds a predetermined value during forming.

10. The method according to claim 1, comprising monitoring the liquid pressure during forming.

11. The method according to claim 1, wherein the tubular body is a steel material.

12. A meandering tubular body produced by a method according to claim 1, the meandering tubular body comprising: a plurality of bending radii with a bending radius of less than three times the tube diameter, and a plurality of substantially uncurved segments that adjoin the bending radii, wherein at least one of the uncurved segments has a substantially polygonal cross section.

13. The meandering tubular body according to claim 12 in a generator, wherein the generator is configured to produce an electric current in a multi-pole synchronous generator of a wind power plant, wherein: the generator has a plurality of grooves, in which a winding is arranged, the tubular body has a plurality of substantially uncurved tube segments having a substantially polygonal cross section, wherein the substantially uncurved segments of the tubular body are arranged in the grooves, the tubular body including a cooling liquid flowing through said segments.

14. The meandering tubular body according to claim 12, wherein a stator of the generator has the plurality of grooves and the winding is a stator winding.

15. The method according to claim 1, wherein changing the cross-sectional shape of at least the portion of the tubular body includes changing the cross-sectional shape of at least the portion of the tubular body to a substantially polygonal cross-sectional shape.

16. The method according to claim 15, wherein the polygonal cross-sectional shape is a substantially rectangular cross-sectional shape.

17. The method according to claim 7, wherein applying force to the tubular body includes using a punch or a roll.

18. The method according to claim 9 wherein discharging the liquid from the tubular body comprises using a pressure relief valve, if the pressure exceeds a predetermined value during forming.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0028] The invention is described in greater detail below by means of preferred illustrative embodiments with reference to the attached figures, of which:

[0029] FIG. 1 shows a first method state during the production of a meandering tubular body,

[0030] FIG. 2 shows a second method state of the method according to FIG. 1, and

[0031] FIG. 3 shows a third method state of the method according to FIGS. 1 and 2.

DETAILED DESCRIPTION

[0032] In its undeformed state, the tubular body 1 shown in FIGS. 1-3 has a substantially cylindrical cross section and is uncurved, as can be seen in FIG. 1. To prepare the forming step, the tubular body 1 is closed pressure tightly in a first end segment 2 by means of a closure 3, e.g., a blind plug. A second closure 5 is fitted in an opposite, second end segment 4. The second closure 5 is designed as a check valve with an excess pressure limiter, for example.

[0033] The tubular body 1 is filled with liquid, preferably via the second closure 5, and pressurized, e.g., with a pressure in a range of from 50 to 200 bar. The tubular body is then closed pressure tightly by means of the optionally provided check valve, wherein the optionally provided pressure limiter is designed to discharge liquid from the interior of the tubular body 1 if a predetermined pressure within the tubular body 1 is exceeded.

[0034] It is then possible to carry out the forming step with the filled and closed and preferably pressurized tubular body 1. In the illustrative embodiment shown, the tubular body 1 is first of all placed in a tube bending device 100, as shown in FIG. 1. The tube bending device 100 holds a first leg of the tubular body 1 against a stop 101. A lever 103 brings about the bending of the tubular body 1 around a retention pin 105 in the direction of the arrow A. Owing to the filling of the tubular body 1 with the liquid, tube bending takes place without the tube cross section collapsing, and a state as shown in FIG. 2 is achieved when the bending process is carried out several times.

[0035] The tubular body shown in FIG. 2, which is bent in a meandering shape and represents an intermediate product of the method of the illustrative embodiment shown, has a plurality of substantially uncurved segments 7, which are each arranged adjoining the bending radii 9 without kinks.

[0036] Starting from the state shown in FIG. 2, the tube cross sections of the substantially uncurved segments 7 are then preferably changed. This is accomplished as shown in FIG. 3 by placing the substantially uncurved segments 7 successively in a die 203 of a punching device 200. The die 203 consists of two parallel bars, for example, which between them define a gap of rectangular cross section, e.g., in the form of a square with the slot width C and preferably the same slot depth.

[0037] By moving a punch 201 repeatedly up and down in the direction of the arrows B, the tubular body 1 is subjected to an external force in the die 203, said force leading to deformation in such a way that the tube cross section is shaped to match the cross section of the slot.

[0038] A pressure-measuring transducer 11, which is designed to monitor the internal pressure of the liquid, is preferably arranged on the second closure 5. If a predetermined pressure value is exceeded, there is the possibility either of discharging liquid manually or of automatic opening of a pressure relief valve if said pressure is exceeded in order to take account of the reduction in volume in the interior of the tubular body 1 due to the change in shape brought about by the punching device 200.

[0039] As can be seen from the above illustrative embodiment, the method can be used for both the combined bending and the changing of the shape of the tube cross section. However, the advantages of stabilizing the volume of the tubular body 1 by means of, preferably pressurized, liquid also come into play in both individual processing steps, i.e., when only bending of the tube cross section is taking place or only a change in the shape of the tube cross section is taking place. It has been found that the use of water allows adequate stabilization, and the environmental compatibility of water is regarded as advantageous for the use thereof.

[0040] As an alternative, the use of oil or the like is likewise envisaged.