METHOD FOR THE PRODUCTION OF A CONVEYING PIPE FOR THE TRANSPORT OF SOLIDS, AND CONVEYING PIPE FOR THE TRANSPORT OF SOLIDS

Abstract

A method for the production of a conveying pipe 18, and to a conveying pipe 18, having a circumferential annular bead 13 in the region of an end segment, for thermally decoupling a double-walled pipe body 1 during the creation of the thermal joining seam 17.

Claims

1. A method for the production of a conveying pipe for a thermal joining seam, having a double-walled pipe body with a hardened inner pipe, and with a pipe collar coupled to at least one end, comprising the following method steps: providing a double-walled pipe body having a hardened inner pipe and an outer pipe which encases the inner pipe; optionally heating the end of the outer pipe; exerting a compressive force on the end face of the outer pipe in such a manner that a longitudinal segment of the outer pipe expands radially outward to create an annular bead at a distance from the end face of the outer pipe, forming a separation gap between the cuter pipe and the inner pipe; placing a pipe collar thereon, and joining the pipe collar thermally to the outer pipe by an external, circumferential, thermal joining seam in the region of the annular bead.

2. The method according to claim 1, wherein the heating is carried out with an inductor, and/or that the end of the outer pipe is heated to 250 C. to 1500 C.

3. The method according to claim 2, wherein the heating is carried out at 750 C. to 1500 C.

4. The method according to claim 2, wherein the heating is carried out at 750 C. to 1000 C.

5. The method according to claim 1, wherein only the longitudinal segment is heated to form the annular bead.

6. The method according to claim 1, wherein an outer pipe is used which has a steel alloy with a carbon content of 0.05 to 0.35 wt %.

7. The method according to claim 1, wherein the thermal joining seam is positioned, with respect to an axial direction of the pipe body, in such a manner that the separation gap is formed between the inner pipe and the outer pipe inwardly in a radial direction.

8. The method according to claim 1, wherein, when the compressive force is applied, an outer contour tool is placed on the outer shell surface of the outer pipe.

9. The method according to claim 1, wherein, when the compressive force is applied, at least one first pipe collar part is placed on the outer shell surface of the outer pipe.

10. The method according to claim 1, wherein, when the compressive force is applied, the pipe collar is placed on the outer shell surface of the outer pipe.

11. The method according to claim 1, wherein the compressive force is applied by a tool and the tool is removed after the molding of the annular bead.

12. The method according to claim 1, wherein the outer tube is quenched after the formation of the annular bead.

13. The method according to claim 1, wherein the pipe collar is placed on the conveying pipe and the compressive force is applied on the outer pipe via the pipe collar.

14. The method according to claim 1, wherein the thermal joining seam contracts upon cooling such that the outer pipe comes to lie with its inner shell surface against the outer shell surface of the inner pipe in the region of the annular bead.

15. The method according to claim 1, wherein a circumferential predetermined deformation point is constructed in the outer pipe in the region in which the annular bead should be formed.

16. The method according to claim 15, wherein the circumferential predetermined deformation point is designed as a circumferential groove.

17. A conveying pipe for the transport of solids, having a double-walled pipe body with a pipe collar coupled on the end thereof, wherein the pipe collar is welded to an outer pipe of the pipe body around the circumference thereof by means of a thermal joining seam, wherein the outer pipe is radially expanded by an annular bead, forming a separation gap toward an inner pipe, below the thermal joining seam with respect to a radial direction.

18. The conveying pipe for the transport of solids wherein it is produced by a method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Additional advantages, features, properties, and aspects of the present invention are the subject matter of the following description. Preferred embodiment are illustrated in the schematic figures. These serve to facilitate understanding the invention. In the figures:

[0031] FIG. 1 shows a production process for a conveying pipe according to the invention,

[0032] FIG. 2 shows an enlarged view of a portion of FIG. 1,

[0033] FIG. 3 shows the conveying pipe produced according to the invention, upon the completion of the production process, and

[0034] FIG. 4 shows an enlarged view of a portion of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0035] In the figures, for reasons of simplicity, the same reference numbers are used for the same or similar components, even if there is no description provided for the same.

[0036] FIG. 1 shows a cutaway view during a process for the production of a conveying pipe 18 according to the invention. A double-walled pipe body 1 is designed for this purpose, having an inner pipe 2 which is particularly tempered, and an outer pipe 3 which surrounds the inner pipe 2. One end 4 of the pipe body 1 is heated by an inductor 5 in the form of an induction coil, and specifically the heating is carried out in a targeted manner in a longitudinal segment 6 defined in the axial direction A. The longitudinal segment 6 is arranged at a distance a from the end face 12, as shown in FIG. 2. In addition, an inner cooling tool 7 is included such that the inner pipe 2 is not heated during the heating of the longitudinal segment 6 and of the outer pipe 3. Subsequently, a double-walled pipe collar 8 is pushed over the end 4 in the axial direction A, wherein the pipe collar 8 has an outer collar 9 and an inner ring 10. The inner ring 10 itself has an extension 11 oriented in the enlarged view in FIG. 2 in the axial direction A, which runs around the circumference and which comes to lie with a positive fit against the end face 12, particularly of the outer pipe 3, when the pipe collar 8 is pushed further. The pipe collar 8 then lies at least partially on the outer shell surface 19 of the outer pipe 3 in such a manner that the outer pipe 3 doesn't expand in this area.

[0037] As the pipe collar 8 is further pressed in the axial direction A, a construction as in FIGS. 3 and 4 results. The previously heated longitudinal segment 6 expands on the outer circumference in the radial direction R and forms a circumferential annular bead 13. As such, the inner shell surface 14 of the outer pipe 3 is decoupled from the outer shell surface 15 of the inner pipe 2, forming a separation gap 16 in the region of the annular bead 13. A circumferential thermal joining seam 17, as well as the thermal influence zone thereof which acts on the outer pipe 3, are consequently thermally decoupled from the inner pipe 2 such that no heat is directed into the inner pipe 2 by the outer pipe 3.

[0038] The extension 11 of the inner ring 10 in this ease has shifted the end face 12 of the outer pipe 3 in the axial direction A relative to the inner pipe 2 such that the annular bead 13 is created.

[0039] The annular bead 13 therefore has a distance a from the free end 4 of the pipe body L As such, after the thermal joining seam 17 is formed, the conveying pipe 18 according to the invention, comprising the pipe body 1 and the pipe collar 8 is finished. As can be seen in FIG. 3, it is also possible that the inductor (5) is shifted in the axial direction (A).

[0040] The fact that the circumferential annular bead 13 can contract back in the radial direction R, such that the separation gap 16 is no longer present and the inner surface of the annular bead 13 lies with a positive fit against the outer shell surface 15 of the inner pipe 2, is not illustrated in greater detail.

List of Reference Numbers:

[0041] 1pipe body [0042] 2inner pipe [0043] 3outer pipe [0044] 4end of 1 [0045] 5inductor [0046] 6longitudinal segment [0047] 7inner cooling tool [0048] 8pipe collar [0049] 9outer collar of 8 [0050] 10inner ring of 8 [0051] 11extension of 10 [0052] 12end face [0053] 13annular bead [0054] 14inner shell surface of 3 [0055] 15outer shell surface of 2 [0056] 16separation gap [0057] 17thermal joining seam [0058] 18conveying pipe [0059] 19outer shell surface of 3 [0060] Aaxial direction [0061] adistance [0062] Rradial direction