FORMING DEVICE AND METHOD FOR SUPPLYING AT LEAST ONE ROOT PROTECTION GAS

Abstract

The invention relates to a forming device (200) for supplying at least one root protection gas to the root side of at least one region (11) of at least one pipe (10) to be connected, comprising at least one root protection gas supply device (220) for supplying the root protection gas and comprising at least one root protection gas conducting device (210) for conducting or deflecting the supplied root protection gas in an axial direction along the inner wall of the pipe (10) along the root side of the region (11) to be connected, wherein the root protection gas conducting device (210) has a cylindrical shape and can be inserted into the pipe (10) in a centered manner, and the root protection gas supply device (220) is arranged within the root protection gas conducting device (210). The invention additionally relates to a method for forming or supplying at least one root protection gas to the root side of at least one region (11) of at least one pipe (10) to be connected. The supplied root protection gas is guided, conducted, or deflected in the direction along the inner face of the pipe (10) along the root side of the region to be connected, and the root protection gas is additionally guided in the radial direction such that when the pipe region is connected to a pipe bend (12), the root protection gas is guided along the curvature of the pipe bend (12) in the axial direction.

Claims

1. Forming device (200) for supplying at least one root protection gas to the root side of at least one region (11) to be connected of at least one pipe (10) and for supplying the root protection gas along a curvature of the pipe bend in the axial direction, comprising at least one root protection gas supply device (220) for supplying the root protection gas and comprising at least one root protection gas conducting device (210) for guiding or deflecting the supplied root protection gas in the axial direction along the inner wall of the pipe (10) along the root side of the region (11) to be connected, wherein the root protection gas conducting device (210) has a cylindrical shape and can be inserted into the pipe (10) in a centered manner, characterized in that the root protection gas supply device (220) is arranged within the root protection gas conducting device (210).

2. Forming device (200) according to claim 1, characterized in that an end face of the cylindrical root protection gas conducting device (210) is at least partially open so that the root protection gas can flow from the root protection gas supply device (220) in the root protection gas conducting device (210) through the end face over an edge of the cylindrical root protection gas conducting device (210) into an intermediate space between the lateral surface of the root protection gas conducting device (210) and the pipe (10) and thus is conducted at least in the region of the root side in the direction along the root side of the region (11) to be connected.

3. Forming device (200) according to claim 1, characterized in that the lateral surface of the cylindrical root protection gas conducting device (210) has at least one hole (211), wherein the root protection gas supply device (220) furthermore interacts with the root protection gas conducting device (210) in such a way that supplied root protection gas is conducted radially from inside to outside through the hole (211).

4. Forming device (200) according to claim 3, characterized in that the lateral surface has the hole (211) in the axial direction closer to one end of the lateral surface than to a center of the lateral surface.

5. Forming device (200) according to claim 1, characterized by at least one sealing element (230) which can be inserted into the pipe (10) for at least partially sealing the supplied root protection gas in an axial pipe direction.

6. Forming device (200) according to claim 1, characterized by at least one centering element (240), which can be inserted into the pipe (10) and in particular permits the passage of gas, for centering the root protection gas conducting device (210).

7. Forming device (200) according to claim 6, wherein the at least one centering element (240) is arranged in the axial direction only at one end with respect to the root protection gas conducting device (210).

8. Forming device (200) according to claim 6, characterized by at least one sealing element (230) which can be inserted into the pipe (10) for at least partially sealing the supplied root protection gas in an axial pipe direction, wherein the at least one centering element (240) and the at least one sealing element (230) are arranged in the axial direction only at one end with respect to the root protection gas conducting device (210).

9. Forming device (200) according to claim 1, wherein the root protection gas supply device (220) is a diffuser.

10. Method for forming or for supplying at least one root protection gas to the root side of at least one region (11) to be connected of at least one pipe (10), wherein the supplied root protection gas is guided, conducted, or deflected in the direction along an inner face of the pipe (10) along the root side of the region to be connected, characterized in that the root protection gas is additionally guided in the radial direction so that when the pipe region is connected to a pipe bend (12), the root protection gas is guided along a curvature of the pipe bend (12) in the axial direction.

11. Method according to claim 10, wherein argon, nitrogen and/or hydrogen are used as root protection gas.

12. Method according to claim 10, that uses a forming device (200) for supplying at least one root protection gas to the root side of at least one region (11) to be connected of at least one pipe (10) and for supplying the root protection gas along a curvature of the pipe bend in the axial direction, comprising at least one root protection gas supply device (220) for supplying the root protection gas and comprising at least one root protection gas conducting device (210) for guiding or deflecting the supplied root protection gas in the axial direction along the inner wall of the pipe (10) along the root side of the region (11) to be connected, wherein the root protection gas conducting device (210) has a cylindrical shape and can be inserted into the pipe (10) in a centered manner, characterized in that the root protection gas supply device (220) is arranged within the root protection gas conducting device (210).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a forming device from the prior art;

[0039] FIG. 2 shows an embodiment of a forming device according to the invention;

[0040] FIGS. 3A-3H show steps in a welding method for a pipe bend at two open pipe ends using an embodiment of a forming device according to the invention;

[0041] FIGS. 4A-4H show steps in a welding method for a pipe bend at an open and a closed pipe end using an embodiment of a forming device according to the invention.

[0042] FIG. 1 has already been explained in the introduction of the description.

[0043] FIG. 2 shows an embodiment of a forming device according to the invention denoted by 200. The forming device 200 is here arranged in a pipe 10 which is currently being welded to a pipe bend 12. The welding point is denoted by 11.

[0044] The forming device 200 for supplying at least one root protection gas to the root side of at least one region to be connected of a pipe 10 comprises a root protection gas supply device 220 for supplying the root protection gas, said supply device here taking the form of a diffuser, and a root protection gas conducting device 210 for guiding or deflecting the supplied root protection gas in the axial direction along the inner wall of the pipe 10 along the root side of the region to be connected, said conducting device functioning as a displacement body. The root protection gas conducting device 210 has a cylindrical shape and can be inserted in a centered manner into the pipe. The root protection gas supply device 220 is arranged within the root protection gas conducting device 210. Root gas is guided into the root protection gas supply device 220 via a root gas supply line 260 on the left-hand side of the figure.

[0045] An end face of the cylindrical root protection gas conducting device 220 is at least partially open so that the root protection gas can flow from the root protection gas supply device 220 in the root protection gas conducting device 210 through the end face over an edge of the cylindrical root protection gas conducting device 210 into an intermediate space between the lateral surface of the root protection gas conducting device 210 acting as displacement body and into the pipe and thus is conducted at least in the region of the root side in the direction along the root side of the region 11 to be connected. The other end face of the cylindrical root protection gas conducting device 210 is completely closed off so that a directed root gas flow is generated from the open end face.

[0046] The lateral surface of the cylindrical root protection gas conducting device 210 has at least one hole 211, wherein the root protection gas supply device 220 furthermore interacts with the root protection gas conducting device 210 in such a way that supplied root protection gas is conducted radially from inside to outside through the hole 211. Here, the root protection gas conducting device 210 is placed such that the flow through the at least one hole 211 is directed into a curvature of the pipe bend 12. This provides a protection gas flow which covers the curvature of the pipe bend 12 that is not encompassed by the gap flow and also prevents the formation of manganese lines here. As a result of the root protection gas guided from inside to outside in addition to in the axial direction, the root protection gas is guided along the curvature of the pipe bend 12 so that, even in the case of curved pipe bends 12, the principle is satisfied that a root protection gas flow be guided in the direction along the root side of the region to be connected, in particular in the direction toward the object and/or in a plane substantially parallel to the region to be connected of the object, for example, along the inner wall of the pipe to be connected.

[0047] The forming device 200 has a sealing element 230 which can be inserted into the pipe 10 for at least partially sealing the supplied root protection gas in an axial pipe direction. The sealing element 230 is here arranged on the side of the root protection gas conducting device 210 where the at least partially open end face is located. In this way, the root protection gas can flow from the root protection gas supply device 220 in the root protection gas conducting device 210 through the at least partially open end face into the intermediate space between the seal and the left end face so that here an overpressure arises, through which the root protection gas flows into the intermediate space between the lateral surface of the cylindrical displacement body 210, or the cylindrical root protection gas conducting device 210, and into the pipe 10.

[0048] The forming device 200 furthermore comprises a centering element 240 which can be inserted into the pipe 10 for centering the root protection gas conducting device. In addition, a gas connection 250 is arranged on the other end face in order to reconnect the gas supply line 260.

[0049] FIGS. 3A-3H show steps in a welding method for a pipe bend at two open pipe ends using an embodiment of a forming device 200 according to the invention.

[0050] FIG. 3A shows how the forming device 200 is inserted into an open pipe in such a way that the sealing element 230 and the centering element 240 remain in the pipe while the root protection gas conducting device 210 partially projects from the pipe. The forming device 200 has two gas connections 250, one on the end of the centering element 240, the other on the end of the root protection gas conducting device 210. The gas supply line 260 is connected to the gas connection 250 which is arranged at the centering element. Now, in FIG. 3B, a pipe bend is placed on the end of the pipe from which the root protection gas conducting device 210 projects. In FIG. 3C, a forming method according to the invention is carried out, wherein the pipe is welded to the pipe bend. In FIG. 3D, the forming device 200 is removed back through the pipe. In FIG. 3E, the forming device 200 is inserted into another open pipe, also in such a way that the sealing element 230 and the centering element 240 remain in the pipe while the root protection gas conducting device 210 partially projects from the pipe. In FIG. 3F, the other end of the pipe bend is placed on the end of the pipe from which the root protection gas conducting device 210 projects. In FIG. 3G, a forming method according to the invention is again carried out, wherein the pipe is welded to the pipe bend. In FIG. 3H, the forming device 200 is removed from the pipe.

[0051] FIGS. 4A-4H show steps in a welding method for a pipe bend to an open and a closed pipe end using an embodiment of a forming device 200 according to the invention.

[0052] In this case, the gas supply line 260 is initially arranged at the gas connection 250. In FIG. 4A, the forming device 200 is inserted into a pipe closed at one end in such a way that the sealing element 230 and the centering element 240 remain in the pipe while the root protection gas conducting device 210 partially projects from the open end of the pipe. The gas supply line 260 also projects with one of the gas connections 250 from the open end of the pipe. Now, in FIG. 4B, a pipe bend is placed on the end of the pipe from which the root protection gas conducting device 210 projects. In FIG. 4C, a forming method according to the invention is carried out, wherein the pipe is welded to the pipe bend. In FIG. 4D, the forming device 200 is removed through the pipe bend.

[0053] The gas supply line 260 is then attached to the other gas connection 250. The steps in FIGS. 4E-4H then correspond to the steps in FIGS. 3E-3H.

REFERENCE NUMBERS

[0054] 10 Pipe [0055] 11 Region to be connected, welding point [0056] 12 Pipe bend [0057] 100 Forming device (prior art) [0058] 110 Root protection gas conducting device, displacement body [0059] 120 Root protection gas supply device [0060] 130 Sealing element [0061] 140 Centering element [0062] 160 Gas supply line [0063] 200 Forming device [0064] 210 Root protection gas conducting device, displacement body [0065] 211 Hole [0066] 212 Flow deflection [0067] 220 Root protection gas supply device [0068] 230 Sealing element [0069] 240 Centering element [0070] 250 Gas connection [0071] 260 Gas supply line