EP2177283B1 - Method and device for aligning tubes on an expander - Google Patents

Description

The invention relates to an apparatus and a method for straightening pipes with a radially expandable expansion tool supported by a pull rod with a spar and a straightening force element acting radially on the outside of the pipe in accordance with the upper grip of the Ansprunchs 1 and 7 (see eg JP-A-61099522 ).

In the manufacture of tubes from sheet metal, which are formed by the U-O-E process, the compression molding process, the 3-roll bending process or the like to form a round slotted tube and then welded, the tube material is subjected in continuous longitudinal seam welding a very high thermal load. A tube produced in this way, which has become crooked during the indentation and is subject to a considerable delay, in particular due to the welding process, is generally odd (banana shape), so that it must be directed to achieve the required straightness. As has been shown in large pipe production, the straightness problem is particularly evident in small diameter (below 30 inch) and thick walled (above 15 mm) pipes.

The tubes are therefore directed with expander heads or tools as described by DE-P S 2 264 207 known. The actual expander tool consists of a pyramidal polygon, on the lateral surface of individual segments are arranged. By moving the Vielkantes relative to the segments they are moved radially, so that thereby increases the diameter of the expander head and the tube expands. The tubes, which are up to 18 m long, are gradually widened and calibrated in this way.

When expanding the tube, however, it comes to asymmetry (tilting) on Expanderwerkzeug, which although a certain straightening effect occurs, especially as the material flows during expansion, but this is low and limited reproducible. Therefore, in practice, together with the expander tool, devices are used which have straightening saddles or rollers placed on the outside of the tube behind the expander head or tool, which act on the tube in the radial direction with a force and initiate a bending moment in the tube with which, in addition to the action of the Expanderwerkzeugs the oddness is to be eliminated. In this case, however, unavoidably occurs also a moment on the spar and the pull rod, via which the expander tool is connected to a slide inserted into the tube displacement device. This has a detrimental effect on the life of the components of the expander, which also adds that the thin spar especially for smaller diameters acts as a soft spring, which is reflected negatively in the directional result.

The invention is therefore based on the object to provide a method and an apparatus of the generic type without the disadvantages described, in particular for straightening pipes with thicker wall thicknesses and higher material strengths and thereby small diameter ranges.

This object is achieved by a device having the features of claim 1. A method for straightening pipes in a device according to the invention is defined in claim 7. By according to the invention, the widening and straightening are functionally separated, asymmetries on the expander tool and on its spar and on the pull rod occurring moments can be avoided. This does not adversely affect the life of the components. Furthermore straightening force and -weg can be initiated controlled, so that a pipe can be targeted and reproducible directed.

The device can be designed so that either only in one plane (because the tube is usually hollow above the weld) or also spatially directed.

Preferably, when three straightening means are connected together, the straightening forces can be generated by only one force applying means, i. with application of force to only one point of the tube, wherein the connection of the straightening means leads to the formation of the directional triangle.

An embodiment of the invention provides that the straightness of the tube is measured and the straightening process is corrected as a function of the measurement results. This can be done immediately manually or at least partially automated.

The straightening means are according to the invention designed as saddles or rollers to be applied to the tube, wherein the mean straightening means also holds the tube with the expander tool in position inside.

A preferred embodiment of the invention provides that for applying the straightening force, the rollers or saddles of only the two outer frameworks against the pipe are adjustable.

If the scaffolds are advantageously connected to each other, the forces can be short-circuited and are not conducted into the foundation or the expander frame.

Another embodiment of the invention provides that in a common support frame, a middle saddle or a middle roller and vertically spaced from each of these at the outer ends of the support frame, a saddle or a roller is arranged, wherein the saddles or rollers are preferably articulated mounted in the support frame. The thus clamped by the three directional force in a plane opposite at three points pipe is subject to the influence of the training triangle due to the common support frame.

This can advantageously already be achieved if only one of the three saddles or one of the rollers is provided with a force-applying means, e.g. a hydraulic cylinder is formed, preferably one of the outer saddles or one of the outer rollers.

Fig. 1

in einer schematischen Längsansicht ein in ein Rohr eingefahrenes Expanderwerkzeug mit von außen als Richtdreieck auf das Rohr aufgebrachten Richtkräften;

Fig. 2

in einer schematischen Längsansicht wie zuvor drei axial voneinander beabstandete Gerüste mit darin angeordneten Richtkraftmitteln; und

Fig. 3

eine schematische Längsansicht wie zuvor in Fig. 1 mit drei in einem gemeinsamen Tragrahmen angeordneten Richtkraftmitteln.

Further details and advantageous features will become apparent from the claims and the following description of illustrated in the drawings embodiments of the invention. Show it:

Fig. 1

in a schematic longitudinal view of a retracted into a tube expander tool with applied from the outside as a direction triangle on the pipe straightening forces;

Fig. 2

in a schematic longitudinal view as before, three axially spaced stands with straightening means arranged therein; and

Fig. 3

a schematic longitudinal view as previously in Fig. 1 with three arranged in a common support frame straightening means.

As in the Fig. 1 to 3 is shown for straightening a curved, not straight, thick-walled tube 1 a retracted by a displacement device, not shown Expanderwerkzeug 2 inside the tube 1. The expander tool 2 is supported by a tie rod 3, which is coaxial with a spar 4 is included. The expander tool 2 can be changed in diameter by mutually displaceable wedge surfaces and serves only to widen the tube 1 to make the material to flow, whereby the force for bending the tube is considerably smaller than non-flowing material.

Separated from this and without any influence or effect on the Expanderwerkzeug 2 including the tie rod 3 and spar 4, the tube 1 is applied to produce the straightness with externally introduced as a directional triangle or applied, indicated by arrows straightening forces F1, F2 and F3. The straightening forces F1 to F3 can be introduced into the tube 1 by straightening force means in the form of rollers 5 or 5a, 5b or saddles 6 or 6a, 6b.

In the execution after Fig. 2 are in three axially spaced-apart stands 7 and 7a, 7b arranged in pairs opposite rollers 5 and 5a, 5b. The middle frame 7 is arranged in the region of the expander tool 2 and holds it in position with the tube 1. On the other hand, the rollers 5a, 5b of the two outer frameworks 7a, 7b of a force application means 8, as indicated by the double arrows, against the tube 1 can be adjusted. The right outer frame 7a is behind and the front outer frame 7b is positioned in front of the expander tool 2. When the scaffolds 7, 7a, 7b are connected to each other (not shown in FIG Fig. 2 ), the introduced straightening forces F1 to F3 short and are not introduced into the foundation 9.

The execution after Fig. 3 has for the straightening means or saddles 6, 6a, 6b a common, here triangular support frame 10 in which the saddles 6, 6a, 6b are articulated. The straightening force to form the straightening triangle, consisting of the straightening forces F1, F2 and F3 (cf. Fig. 1 ), is generated only in one place, by a force applying means 11 assigned to the right outer saddle 6a.

In any case, only the straightening work to produce the straightness of the tube 1 is performed by the directional triangle of the straightening forces F1 to F3, while the expander tool 2 only widens only the tube 1 and even performs no straightening work.

LIST OF REFERENCE NUMBERS

1

pipe

2

Expander tool / expander

3

pull bar

4

Holm

5; 5a, 5b

Role / leveling force means

6; 6a, 6b

Saddle; Directional force means

7; 7a, 7b

framework

8th

Kraftbeaufschlagungsmittel (double arrow)

9

foundation

10

supporting frame

11

force loading

Claims (10)

1. A device for straightening pipes with a radially expandable expansion tool that penetrates into the pipe and is carried by a tie rod with column, as well as means for exerting a straightening force that radially act upon the pipe from outside,
   characterized in
   that three means for exerting a straightening force are assigned to the expansion tool (2) and axially spaced apart from one another, wherein the central means for exerting a straightening force (5; 6) is provided in the region of the expansion tool (2), and in that the means for exerting a straightening force are realized in the form of saddles (6; 6a, 6b) or rollers (5; 5a, 5b) being placed against the pipe (1), wherein the rollers (5; 5a, 5b) or saddles (6; 6a, 6b) are arranged in stands (7; 7a, 7b) such that they lie opposite of one another in a paired fashion.
2. The device according to claim 1,
   characterized in
   that the rollers (5a, 5b) or saddles (6a, 6b) of the two outer stands (7a, 7b) can be adjusted relative to the pipe (1).
3. The device according to one of claims 1 or 2,
   characterized in
   that the stands (7; 7a, 7b) are connected to one another.
4. The device according to claim 1,
   characterized in
   that a common supporting frame (10) accommodates a central saddle (6) or a central roller (5), as well as a saddle (6a, 6b) or roller (5a, 5b) that is vertically spaced apart therefrom and respectively arranged on the outer ends of the supporting frame (10).
5. The device according to claim 4,
   characterized in
   that the saddles (6; 6a, 6b) or rollers (5; 5a, 5b) are respectively mounted in the supporting frame (10) in an articulated fashion.
6. The device according to claim 4 or 5,
   characterized in
   that one of the saddles (6a or 6b) or one of the rollers (5a or 5b) is realized with a force application means (11).
7. A method for straightening pipes with a radially expandable expansion tool (2) that penetrates into the pipe (1) and is carried by a tie rod (3) with column (4), as well as means for exerting a straightening force that radially act upon the pipe (1) from outside, namely in a device according to one of claims 1 to 6,
   characterized in
   that the expansion tool (2) merely expands the pipe (1) in order to cause the material to flow and the externally introduced straightening forces (F1, F2, F3) are applied onto the pipe (1) in the form of a straightening triangle.
8. The method according to claim 7,
   characterized in
   that the straightening forces are introduced in one plane.
9. The method according to claim 7 or 8,
   characterized in
   that the straightening forces are generated by at least one force application means (11) if three interconnected means for exerting a straightening force are provided.
10. The method according to one of claims 7 to 9,
    characterized in
    that the straightness of the pipe (1) is measured and the straightening processes corrected in dependence on the measuring results.

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