EP0154030B1 - Apparatus for enlarging tube ends - Google Patents

Abstract

A flaring device for pipe ends including an insert member centrally insertable into a pipe end, the insert member having mounted thereon synchronously operable pressure plungers arranged at the outer circumference thereof and bringable into engagement with the inner circumference of the pipe end to be flared, includes a calibrating ring for determining a maximum outer circumference defined by the pressure plungers mounted on the insert member, the calibrating ring being in operative engagement with the insert member.

Description

The invention relates to an expanding device for pipe ends with a central insert body.

From DE-A-29 44 435 an expanding device for pipe ends is known which has a central insert body and pressure pistons which are arranged on the outer circumference and can be brought into engagement with the inner circumference of the pipe to be expanded and can be synchronously adjusted. These pressure stamps are designed as strips which are pressed outwards by an elastic cylindrical bellows. The pressure rams mounted in the insert body are assigned a calibration ring that determines their maximum outer circumference on the outside of the pipe to be expanded.

With such an arrangement of the calibration ring on the outer circumference of the pipe to be expanded, the pipe end can be brought to a predetermined outer diameter, whereby a round outer surface can be achieved. However, the inner surface of the pipe end machined with the known expanding device is out of round. The consequence of this is that the inner edges of two pipe ends to be connected to one another are offset at the joints. When welding thick-walled and highly stressed pipes of larger diameter (larger than 200 mm), such as those used in power plant construction and sometimes also in the chemical industry, it is absolutely essential that the inside diameters of the pipe ends to be welded to one another exactly match. This affects both the overall diameter and any out-of-roundness of the two pipe ends. Bumps in the interior of the pipe caused by misalignment not only lead to a swirling of the medium flowing in it, but also to the accumulation of impurities and to premature corrosion in these areas. Butt joints also impede inspection and maintenance with devices that can be moved inside the pipes. It is much more important, however, that the edge offset in the ultrasound inspection produces error indications that cannot be distinguished from any real error points that may be present. Because the ultrasonic inspection of the weld seam zones is mandatory for highly stressed pipes, the welding of pipe ends with non-flush edges is not permitted for this reason alone. In addition, however, the strength of a weld seam is negatively influenced by the edge offset, because there is a risk, particularly when machine welding, that the root seam is not welded through.

A widening device is also known in which the pipe end can be widened by means of a conical pressure stamp which can be displaced axially relative to the pipe (GB-A-2 066 122). The pressure stamp has three widening jaws, each covering one third of the inner circumference of the tube to be widened. This device can also be used to widen thick-walled pipe ends. However, the device is designed as a stationary machine and is not suitable for on-site installation due to its high weight and its considerable dimensions. In addition, it is a peculiarity of this device that it requires considerable experience of the operating personnel in order to expand a pipe to a certain predetermined inside diameter. Not only the inevitable spring back of the pipe wall as such must be taken into account here, but this spring back also depends on the type of material of the pipe wall and on the wall thickness. This means that it has to be widened in several layers and repeatedly measured in between. The measurement of non-round tubes is quite difficult and only possible with the inner circumference tape measure.

The invention is based on the object of developing a widening device for pipe ends which produces defined inner diameters during widening and largely avoids out-of-roundness of the inner surface. In addition, the expansion device should also be easy to use. In particular, it should be possible to expand it quickly and reliably to a specific, predeterminable inner circumference. In addition, the expansion device should be manageable on site.

The object is achieved according to the invention by the features specified in the characterizing part of claim 1. Advantageous further developments are described in the subclaims.

The advantages that can be achieved with the invention can be seen primarily in the fact that it can be widened to a round inner tube surface with a predetermined inner diameter. This means that the supplier of the pipes has to make less demands on the required tolerances and can therefore obtain the pipes cheaper.

The area of application of the expansion device can be significantly expanded if the calibration ring is designed to accommodate insert rings of different inner diameters. In this case, different pipe sizes or expansion sizes can be covered with one and the same calibration ring and a set of insert rings.

In the case of non-round pipe ends and pipes with an uneven wall thickness, a central expansion can be achieved if the calibration ring is centered on the insert body and this insert body can in turn be fastened centered on a previously known pipe centering device inserted in the pipe.

It is also possible to enlarge the area of use of a tube expander designed for larger tube diameters in that the calibration ring is stored inside the insert body and the pressure stamps can be brought into engagement with the calibration ring via extensions. This creates the prerequisite for this. carry out different expansions with one and the same calibration ring. This is particularly the case if, by adjusting the calibration ring relative to the insert body, areas of the calibration ring with different radial distances from the axis of symmetry can be brought into engagement with the extensions of the pressure stamps. Alternatively, the stroke of each plunger can be continuously limited by means of a wedge-shaped stop bolt, which can be adjusted transversely to its guide and axially to the insert body by means of a longitudinal slot in the plunger.

A particularly clean expansion form is obtained if the pressure stamps in the insert body are arranged inclined up to 10 degrees or up to the limit of the static friction angle with respect to a plane oriented perpendicular to the pipe axis. In this way, step impressions of the pressure stamp on the inner tube wall are avoided.

• Fig. 1 eine schaubildliche Ansicht einer in ein Rohrende eingesetzten, erfindungsgemäßen Aufweitvorrichtung,
• Fig. 2 die teilweise aufgebrochene Stirnseite der Aufweitvorrichtung der Figur 1,
• Fig. 3 einen Schnitt längs der Linie 111-111 der in einem Rohrende zur Anlage gebrachten Aufweitvorrichtung der Figur 2 und durch einen an der Aufweitvorrichtung angelegten Kalibrierring,
• Fig. 4 eine Aufsicht auf die durch den Paßkörper verschlossene Seite der Rohraufweitvorrichtung der Figur 1,
• Fig. 5 eine andere längs der Symmetrielinie und durch einen Druckstempel geschnittene erfindungsgemäße Aufweitvorrichtung,
• Fig. 6 einen Schnitt durch die Anlagefläche für die Druckstempel eines gegenüber dem Ausführungsbeispiel der Figur 5 abgewandelten Kalibrierringes,
• Fig. 7 einen Querschnitt durch einen Teil einer anderen erfindungsgemäßen Aufweitvorrichtung mit einem im Innern des Einsatzkörpers angeordneten Kalibrierring,
• Fig. 8 einen Längsschnitt durch einen Druckstempel einer Aufweitvorrichtung mit eingelassenen elastischen Abstandshaltern für die Schweißlippe,
• Fig. 9 eine Ansicht des um 90° geschwenkten Druckstempels der Figur 8, und
• Fig. 10 einen Schnitt durch einen anderen Abstandshalter für die Schweißlippe.

Further details of the invention are explained on the basis of the exemplary embodiments shown in the figures. Show it:

• 1 is a perspective view of an expanding device according to the invention inserted into a pipe end,
• 2 shows the partially broken end face of the expanding device of FIG. 1,
• 3 shows a section along the line 111-111 of the expanding device of FIG. 2 brought into abutment in a pipe end and through a calibration ring placed on the expanding device,
• 4 is a plan view of the side of the tube expanding device of FIG. 1 closed by the fitting body,
• 5 shows another expansion device according to the invention, cut along the line of symmetry and cut by a pressure stamp,
• 6 shows a section through the contact surface for the pressure stamp of a calibration ring modified compared to the exemplary embodiment in FIG. 5,
• 7 shows a cross section through part of another expansion device according to the invention with a calibration ring arranged inside the insert body,
• 8 shows a longitudinal section through a pressure stamp of an expanding device with embedded elastic spacers for the welding lip,
• 9 is a view of the pressure stamp of FIG. 8 pivoted through 90 °, and
• Fig. 10 shows a section through another spacer for the welding lip.

In the diagrammatic representation of FIG. 1 and FIG. 2, the individual pressure stamps 2 to 14 of the expanding device 15, which bear against the inside wall of the pipe end 1 to be expanded, can be clearly seen. The central bore 16 of the insert body 17 of the expansion device 15 carrying the pressure rams can also be clearly seen here. On the front of the insert body, the adjusting screws 18 to 41 protrude for the stroke limitation of the individual pressure stamps. The insert body 17, as can also be seen in FIG. 2, is provided on one side with an approximately 42 mm wide gap 42. This gap is shown filled in in Figure 1 and in Figure 2 by a fitting body 43. This fitting body carries a projecting connecting lug 44, with which it can be connected during axial insertion into the gap 42 via a hydraulic connector 45 to the central hydraulic line 46 running in the insert body 17 for the remaining pressure stamps. This central hydraulic line can be connected to a hydraulic supply line 48 via a further hydraulic connector 47. A further supply hose 49 for a pipe centering device (not shown) located deeper in the pipe is shown through the central bore 16 in the illustration in FIG. 1.

The internal structure of the insert body 17 is best illustrated in FIGS. 2 and 3. In the broken-open section of FIG. 2, the pressure rams 2 to 14 arranged radially on the circumference of the insert body 17 can be seen, and the bores 50 to 54 of the insert body, which are stepped in the exemplary embodiment, in the manner of a piston are radially displaceable. These plungers, which are adapted to the diameter of the bores 50 to 54, have annular grooves 55 to 66, in each of which an O-ring 67 to 78 is inserted for sealing. FIG. 2 also clearly shows that the pressure punches 2 to 14 have a longitudinal slot 79 to 84 in their smaller diameter, through which a stop pin 85 to 90 is passed. The stroke of the pressure ram is limited in both directions by this stop bolt. As can be seen in FIG. 3, the stop bolts have a lower wedge-shaped edge 91 which has the same inclination to the axis of symmetry of the pressure stamp as the end of the longitudinal slot 84 in the pressure stamp 11 facing them. The stop bolt 90 can be adjusted by means of an adjusting screw 26 depending on the position Screw in different lengths into the longitudinal slot 84 of the pressure stamp 11. In addition, the hydraulic connector 47 for the central hydraulic line 46 is shown in section in FIG.

In FIG. 3 it can also be seen that the pressure stamps 11 are not exactly radially inclined, but rather out of the section plane of FIG. 2 perpendicular to the axis of symmetry 92 of the insert body by approximately 5 degrees to the tube. Because the surfaces of the pressure stamps 2 to 14 facing the inner wall of the pipe end 1 to be expanded, as shown in FIG. 2, have a cylindrical curvature which has approximately the same radius as the inner radius of the pipe to be expanded, the consequence of this is that their pipe-facing, the Inner edges facing the inner tube wall when expanding the pipe end, do not press into the pipe inner wall. The expansion contour achieved thus remains funnel-shaped. The stop pins 85 to 90 not only limit the maximum stroke of the pressure rams, but also prevent them from rotating about their longitudinal axis. As a result, the cylindrical curvature of the outer surface of the pressure stamp remains aligned with the curvature of the inner tube wall.

The calibration ring 93, which is pushed over the expansion device 15 in the sectional view in FIG. 3, extends with its stop surface 94 over the pressure rams 2 to 14, which project over the pipe end 1 during operation. The calibration ring 93 limits the maximum stroke of the pressure stamps 2 to 14, provided that this limit was not previously made by the stop bolts 85 to 90. For this purpose, the radius of the cylindrical curvature of the parts of the pressure stamps 2 to 14 which can be brought into engagement with the calibration ring 93 is pivoted back by that 5 degrees relative to the axis of symmetry of the pressure stamps, which pivoted them out of the plane oriented perpendicular to the axis of symmetry 92 of the insert body 17.

FIG. 4 shows a top view of that side of the expanding device 15 on which its gap 42 is closed by the fitting body 43 used. The fitting body 43 inserted in the gap in the axial direction, the. Cross section can be seen in Figure 2, is prevented on both sides by a guide edge 95, 96, which fits into a corresponding guide groove 97, 98 of the insert body 17, to migrate radially. The connecting lug 44 aligned parallel to the axis of symmetry 92 of the insert body 17 carries, as shown in FIG. 4, the hydraulic connector 45. This hydraulic connector fits a corresponding connector counterpart of the insert body 17, which is connected to the central hydraulic line 46 (FIG. 3) inside the insert body connected.

If it turns out when welding thick-walled pipes that the pipe ends to be welded to one another have different diameters, or that the two pipe ends are out of round in different ways, the smaller pipe end or both pipe ends can be expanded to a predetermined size with the expansion device 15. For this purpose, the expanding device only needs to be inserted into the pipe end to be expanded. If a pipe centering device had already been inserted in this pipe end, it can remain in the pipe and only the fitting body 43 is pulled out of the gap 42 of the insert body 17 and this is then pushed with the gap 42 over the supply hose 49 for the pipe centering device located in the pipe. Then the fitting body 43 can be inserted parallel to the axis of symmetry 92 of the insert body 17 until the connector of the central hydraulic line of the insert body snaps into the hydraulic connector on the connecting lug 44 of the fitting body 43. Now the pressure stamp 8 of the fitting body, like the other pressure stamps, is connected to the central hydraulic line 46 of the insert body.

With the insert body 17 inserted in the pipe end, the pressure rams 2 to 14 are pressed against the inner wall of the pipe end 1 to be expanded by increasing the hydraulic pressure by means of a hand pump (not shown). It should be ensured that the pressure rams protrude approximately half from the pipe end in the axial direction. The calibration ring 93 is placed over these above pressure stamps. This limits the stroke of the pressure ram when the pipe end is widened and ensures that the edge of the pipe end is widened to a circular radius. The expansion process has become problem-free for the operating personnel, because when the hydraulic system is manually inflated, a clear resistance can be felt as soon as the pressure stamp not only comes into contact with the pipe wall but also with the calibration ring 93. Due to the large number of pressure stamps used - twenty-three in the exemplary embodiment - and the rigidity of the much thicker calibration ring 93, a completely round expansion of the pipe end 1 is ensured.

However, the pressure stamps can also be individually limited in their stroke by moving the stop bolts 85 to 90 parallel to the axis of symmetry 92 of the insert body 17. In this case too, the hydraulic pressure or the pump resistance increases as soon as the inner wall of the longitudinal slots 79 to 84 come to rest against the stop bolts 85 to 90. This is a clear sign that the expansion process has ended. When using a calibration ring 93, as shown in FIG. 3, the exact placement of the individual pressure stamps 2 to 14 on the inner tube wall or on the calibration ring can be aligned by means of small, if necessary embedded in the end wall of the calibration ring 93, aligned approximately parallel to its axis of symmetry Observation holes 99 (FIG. 3) can also be checked visually.

FIG. 5 shows a particularly expedient shape for a pressure stamp 100, which makes it easier to observe the system on the calibration ring 101. The outer circumference of the pressure stamp is L-shaped, with a seat surface 102 for the installation of the pipe end 103 and an end surface 104 for contact with the calibration ring 101. The difference in height between the seat surface 102 and the end surface 104 is equal to or greater than the largest tube wall thickness to be expanded with this pressure stamp. While the seat surface of the pressure ram 100 is intended to rest on the pipe end 103 to be widened, the end face 104 is intended to rest against the calibration ring 101 or to rest against an insert ring 105 to be inserted in the calibration ring. Seat surface 102 and end face 104 of the pressure stamp 100 are curved cylindrically in accordance with the radius of the inner tube wall or the insert ring. The calibration ring 101 itself carries one inner circumferential shoulder 106 which fits into a corresponding extension ring 107 of the insert body 108. In the outer circumferential shoulder 109 of the calibration ring 101, insert rings 105 of the same diameter but of different thickness can be inserted.

When using a pressure stamp 100 designed in this way, when the pipe end 103 is expanded, the contact of the individual pressure stamps of the expansion device on the insert ring 105 or on the circumferential outer shoulder 109 of the calibration ring 101 can also be visually observed. If all the pressure stamps rest on the insert ring 105 or on the outer circumferential shoulder 109 of the calibration ring 101, then the pipe end 103 is widened to the desired diameter, provided that the springback effect has been taken into account in the diameter of the calibration ring. Another measurement is then unnecessary. By guiding the calibration ring 101 with its inner circumferential shoulder 106 on the attachment ring 107 of the insert body 108, a central expansion to the insert body is forced. This is particularly advantageous if this insert body is in turn centrally coupled to a guide 143 (FIG. 3) of a pipe centering device (not shown) located further inside the pipe. This pipe centering device must then - after. Removal of the expanding device - remain in the two pipe ends and keep them centered until the weld is sufficiently firm. In this case, even in the case of non-round pipes and pipes with an uneven wall thickness, an expansion that is central to the pipe is forced. The use of different insert rings 105 makes it possible to use one and the same calibration ring 101 by varying the insert rings 105 to widen the tube end 103 to different extents or to widen the tube ends of different widths to a certain extent. Through the additional use of several sets of pressure stamps 100 of different lengths, the area of use of the expansion device can be considerably expanded with one and the same insert body 108 and one and the same calibration ring 101 as well as a set of insert rings 105 with different inner diameters. This can also be achieved in that the pressure stamps 122 - as shown in FIG. 8 - are formed in two parts and the part 144 of the pressure stamp that can be brought into contact with the pipe is replaced by one with a different height.

FIG. 6 shows a section through the circumferential outer shoulder 110 of another calibration ring 111, in which the stop dimension can be determined by individually adjustable stop screws 113, which are to be secured with lock nuts 112, instead of by using insert rings of corresponding inner diameter. This calibration ring 111 can also be used for special tasks in which different widening over the circumference is desired. In addition, the same expansion tasks that can also be carried out with the calibration ring 101 and with an insert ring 105 in accordance with the exemplary embodiment in FIG. 5 can thus be carried out. The conversion of this quay ring 111 to a new expansion diameter is, however, because of the necessary measurement of the width between the individual stop screws 113, much more complex than with a calibration ring according to FIG. 5, where only the insert ring 105 has to be replaced.

FIG. 7 shows a section of another insert body 114, as is indicated for expanding devices for particularly large pipe diameters. In this case, the calibration ring 115 is located inside the insert body. It has sawtooth-shaped inclined surface parts 116 to 118 on its inner circumference. These parts can be brought into engagement with correspondingly inclined surface elements 119 of inward projections 120 of the individual pressure stamps 121. Here the maximum stroke of the pressure stamp 121 and the maximum expansion size of the tube 122 determined thereby are determined according to the rotational position of the calibration ring 115 in the insert body 114. With this device, the stroke of the pressure stamp can be changed particularly quickly. With this insert body 114 there is also the possibility of retracting the pressure stamps 121 into their starting position after the expansion process has ended by rotating the calibration ring 115. The initial setting of this calibration ring can be carried out precisely, quickly and easily if the pressure stamp 121 is pressed against a calibration ring 101 (FIG. 5) with an appropriately selected insert ring 105 and then the inner calibration ring 115 until it rests on the inclined surface elements 119 of the extensions 120 turns and locked in this position.

FIGS. 8 and 9 show a pressure stamp 122 with an L-shaped cross section, similar to the pressure stamp shown in FIG. 5. Here, however, a plastic plug 127 is inserted in order to protect the welding lips 123 of the pipe end 124 in the angular corner between the seat surface 125 and the flank leading to the end surface 126. This construction is particularly advantageous when the expansion device for central expansion to the pipe, as indicated in FIG. 3, is coupled to a pipe centering device (not shown) clamped in the pipe and consequently can no longer deflect axially to the pipe. In this case, the inclined position of the plunger axles 122 relative to the vertical on the axis of symmetry 129 of the insert body 130 causes compression forces on the end edges of the tube end 124 when the tube end is expanded, which can lead to damage to the welding lip 123. The forces exerted axially on the pipe edge here can be absorbed by this flexible plastic plug 127. As FIG. 9 shows, it is particularly advantageous for each printing stamp 122 two plastic plugs 127, 131 to be arranged side by side. This prevents the pressure stamp 122 from rotating about its longitudinal axis 128 and thus ensures that the pressure stamp cannot press in the welding lip 123 with its side edges.

FIG. 10 shows a variant of the pressure stamp construction of FIGS. 8 and 9. Here the pressure stamp 132 is drilled out in the area of its angle between the seat surface 133 and the flank leading to the end surface 134 and is inserted into this bore 135 by a compression spring 136 in the direction of the seat surface to pressed round material 137 used. This round material has a wider collar 138, which limits the protrusion of the round material on the side of the seat surface 132 to a few millimeters. A bushing 139 is welded to the side of the bore 135 facing away from the seat surface. It is provided with a screw cap 140 on which the compression spring 136 is supported. The round material 137 can be pressed back against the force of the compression spring 136 when the axial compression forces increase at the end edge of the pipe end and thus protect the welding lip 142 from damage in a similar manner to the plastic plugs 127, 131 of the exemplary embodiment in FIGS. 8 and 9.

Claims (28)

1. Expanding device for pipe ends with a central insertable body (17, 108, 114, 130) with synchronously movable force members (2 to 14, 100, 121, 122, 132), which are arranged on the outer circumference and may be brought into contact with the inner circumference of the pipe to be expanded, wherein a calibrating ring (93, 101, 111. 115) is associated with the force members (2 to 14, 100, 121, 122, 132) housed in the insertable body (17, 108, 114, 130) and determines their maximum outer circumference, characterised in that the force members (2 to 14, 100, 121, 122. 132) can be brought into place with their outer circumference immediately on the calibrating ring (93, 101, 111, 115) and on the inside wall of the pipe (1, 103, 122, 124, 141).

2. Expanding device according to claim 1. characterised in that the calibrating ring (93. 101. 111) is an annulus with a rotating outer shoulder (94, 109, 110) projecting towards the expanding device (15).

3. Expanding device according to claim 1. characterised in that the calibrating ring (101) is constructed to receive spacers (105) of various internal diameters.

4. Expanding device according to claim 3. characterised in that the calibrating ring (101, 111) can be centrally fixed to the insertable body (108, 130).

5. Expanding device according to claim 1, characterised in that the calibrating ring (111) is equipped on its outer circumference with individually adjustable stops (113) which can be brought into contact in each case with a force member located opposite (100, 122, 132).

6. Expanding device according to claim 5, characterised in that adjusting screws, which can be fixed by counter nuts (112), are used as stops (113).

7. Expanding device according to claim 1, characterised in that the calibrating ring (115) is housed inside the insertable body (114) and that the force members (121) can be brought into contact with the calibrating ring (115) by means of. extensions (120).

8. Expanding device according to claim 7, characterised in that by displacing the calibrating ring (115) relative to the insertable body (114). regions (116, 117, 118) of the calibrating ring (115) at various radial distances from the symmetry axis (92) can be brought into contact with the extensions (120).

9. Expanding device according to claim 8, characterised in that the extensions (120) have shoulders (119), which may be brought into contact with the inner side of the calibrating ring (115).

10. Expanding device according to claim 9, characterised in that the inner surfaces (116, 117, 118) of the calibrating ring (115), which can be brought into contact with the shoulders (119) of the extensions (120), are bevelled and serrated.

11. Expanding device according to claim 9, characterised in that the inner surfaces (116, 117, 118) of the calibrating ring (115), which can be brought into contact with the shoulders (119) of the extensions (120), change their internal diameter conically in an axial direction, and that the calibrating ring (115) can be moved axially in relation to the insertable body (114).

12. Expanding device according to claim 1, characterised in that the calibrating ring (93) has bore holes (99) through which the arrangement of the force members (2 to 14) on the pipe (1) or on the calibrating ring (93) can be observed.

13. Expanding device according to claim 1, characterised in that the force members (2 to 14, 100. 121, 122, 132) are part of a piston which can be moved in a hydraulic or pneumatic cylinder (50 to 54).

14. Expanding device according to claim 13, characterised in that the hydraulic or pneumatic cylinders (50 to 54) are arranged radially in the insertable body (17, 108, 114, 130).

.15. Expanding device according to claim 1, characterised in that the force members can be acted upon bilaterally in a respective pressure cylinder.

16. Expanding device according to claim 1, characterised in that the hub of each force member (2 to 14) can be continually delimited by means of a key (85 to 91), which can be moved axially to the insertable body (17) through a slit (79 to 84) in the force member at right angles to the latter's direction.

17. Expanding device according to claim 1, characterised in that at least one further set of force members with a different height is associated with an insertable body for extending the operative range.

18. Expanding device according to claim 17, characterised in that the force members (122) are constructed in two parts and that the part (144) of the force member which can be brought into place on the pipe can be replaced by one with a different height or contour.

19. Expanding device according to claim 1, characterised in that the force members (2 to 14, 100, 121, 122, 132) are arranged in the insertable body (17, 108, 114, 130) and inclined by up to 10 degrees towards the pipe relative to a plane directed vertically to the pipe axis (92).

20. Expanding device according to claim 1, characterised in that the outer surfaces of the force members (100, 121, 122, 132) are constructed in an L-shape. whereby the inner shoulders (102, 125, 133) can be brought into place on the pipe wall and the upper faces can be brought into place on the calibrating ring (101).

21. Expanding device according to claim 1, characterised in that the insertable body (17, 108, 114, 130) has a slit (42), which is at least ten millimeters wide and can be sealed by a removable adjusting body (43).

22. Expanding device according to claim 21, characterised in that the adjusting body (43) is secured in the slit (42) so that it is form-closed against radial displacement.

23. Expanding device according to claim 22, characterised in that the adjusting body (43) has at least one individual force member (8) which can be connected to the supply lead (46) of the remaining force members.

24. Expanding device according to claim 1, characterised in that the insertable body can be assembled from several segments, which can be oppositely secured against radial displacement.

25. Expanding device according to claim 24, characterised in that the segments of the insertable body can be secured against mutual axial displacement.

26. Expanding device according to claim 1, characterised in that the calibrating ring is constructed in multiple parts for threading via a supply line (49) and the parts can be form- closedly connected together in the direction of pull.

27. Expanding device according to claim 1, characterised in that the insertable body (17, 108, 114, 130) is provided with means for central fixing on to a pipe centering device inserted into the pipe to be expanded.

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