Method and apparatus for creating a T-shaped branch of a pipe

Abstract

The present invention relates to a method and an apparatus for manufacturing a T-shaped branch for a pipe by joining the end of a branch pipe to the edge of a hole in a main pipe by internal welding. The hole in the main pipe (T) and the arc corresponding to the end of the branch pipe (P) in the main pipe are mechanically cut by dry machining by removing one solid part from the hole and two solid parts (22) from the end of the branch pipe, where the cleanliness of the joint remains weldable. The end of the branch pipe (P) is arranged around the hole in the main pipe (T), and the joint between the pipes is welded by internal welding without using a welding additive. A branch hole suitable for this is made by punching at right angles to the central axis of the main pipe such that the part separated from the main pipe by the punch (1) is pushed into the punch hole (10) of the inner support (9).

Description

Technical Field

[0001] The present invention relates to a method and apparatus for making a T-branch of a pipe by internally welding the end of a formed branch pipe to the edge of a hole in a main pipe.

[0002] The invention also relates to an apparatus that can be used for drilling a hole in the main pipe required for the method. The goal of this invention is to ensure that an appropriate amount of material remains inside around the hole in the main pipe for welding parts from the inside without introducing additional material from the outside.

Background Art

[0003] The end of the branch pipe is cut into an arc suitable for the main pipe using, for example, the methods and apparatus known from Patent Publication US10537948.

[0004] When making a T-branch of a pipe, there are several methods for making a hole in the pipe to create the branch pipe. In the case of relatively small pipes, the most common method is drilling. Drilling generates chips and requires the use of cutting oil for efficient machining. The chips and cutting oil need to be removed when performing buttwelding, and the parts usually need to be cleaned by warm water washing, which is disadvantageous in terms of productivity and the environment. Also, drilling holes in pipes is a relatively slow production method.

[0005] The easiest way to make a hole suitable for manufacturing a T-branch is the punching method of driving a round punch perpendicular to the longitudinal axis of the pipe. This is effective when the branch pipe is somewhat smaller than the main pipe. The present invention targets such cases. Patent Application FI20217012 discloses a punching method and apparatus for making an oval hole in the wall of a pipe with a circular cross-section. This hole can be used to make a T-branch collar by bending the edge of the hole and extending it into the collar.

Summary of the Invention

[0006] The object of this invention is to provide a method and an apparatus capable of implementing the machining process of a T-shaped branch component as a "dry process" without using cutting oil and without performing cleaning. For this purpose, a punching method and apparatus suitable for drilling holes in the main pipe are used, so that the formed end of the branch pipe smaller than the main pipe can be directly connected by internal welding at the edge of the hole.

[0007] In the method according to the invention, the hole in the main pipe (T) and the arc corresponding to the end of the branch pipe (P) at the main pipe are machined mechanically by dry machining in which the cleanliness of the joint is maintained in a weldable state, removing one solid part from the hole and two solid parts from the end of the branch pipe, the main pipe is supported from the outside by retaining jaws, the main pipe is supported from the inside by an expandable inner support around the hole to be machined, the hole for the branch pipe is machined by a punch guided by the guide hole of the second retaining jaw and moving perpendicular to the central axis of the main pipe, the formed end of the branch pipe (P) is arranged around the hole of the main pipe (T), and the joint between the pipes is welded by internal welding without a welding additive.

[0008] Examples of methods and apparatuses for performing internal welding are disclosed in publications US6433307 (B1), EP1633520 (B1), and WO2019166689. Regarding the features related to internal welding, based on these publications, those skilled in the art can utilize the present invention.

[0009] In the apparatus according to the invention, an inner support with a special structure is used so that the shape of the main pipe does not change when the punch penetrates the wall of the main pipe and enters the punch hole of the inner support. The characteristics of this apparatus are shown in claim 4.

[0010] When the branch pipe is smaller than the main pipe by a certain amount, by matching the shape of the edge of the hole in the main pipe with the shape of the inner circumferential surface of the end of the branch pipe, the material thickness of the joint overlap can be made suitable for welding the parts from the inside without bringing in an additive from the outside.

[0011] Preferred embodiments of the present invention are disclosed in the dependent claims of the method and apparatus.

Brief Description of the Drawings

[0012] Hereinafter, the present invention will be described using exemplary embodiments with reference to the accompanying drawings.

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0014] The branch hole 20 (FIG. 4) is punched into the main pipe T with a punch 1 having a circular cross-section. The cutting edge 3 of the punch 1 has a steel edge, and the distance between the two lowest points thereof corresponds to the longitudinal length of the pipe to be punched (FIG. 2). In this case, the cutting force acts not as an impact but rather as an incision, and the separated part is formed and separated in a controlled state.

[0015] During punching, the pipe is supported from the outside by holding jaws 4 and 5. The holding jaws 4 and 5 are provided with support troughs 6 and 8 for receiving the pipe to be punched. The curvature of the support trough corresponds to the curvature of the outer surface of the main pipe T. At the main pipe support position, the holding jaws 4 and 5 are slightly separated from each other. The second holding jaw 5 is movable back and forth, whereby the pipe can be placed between the holding jaws 4 and 5 within the clamp grips of the troughs 6 and 8.

[0016] The first part 4 of the holding jaw for Joe is provided with a punch guide hole 7 for receiving the punch 1. The guide hole 7 has a central axis in the moving direction of the punch 1, which is perpendicular to the central axis of the cylinder formed by the surfaces of the support troughs 6, 8 at the pipe support position. In this case, when the pipe T is between the holding jaws 4, 5 and is supported at the pipe support position by the support troughs 6, 8, the central axis of the punch 1 is directed perpendicular to the central axis of the pipe T.

[0017] Also, the punching device includes an inner support 9 for supporting the main pipe T from the inside during punching. The inner support is necessary to prevent deformation of the main pipe T to be cut in the cutting situation where the punch penetrates the wall. The inner support has a punching hole 10 that houses the punch 1 and spreads downward so that the cut-off piece falls from the inner support when the inner support 9 is pulled out of the pipe. The inner support 9 must support the pipe near the outer peripheral edge of the punch 1, that is, immediately near the punch hole 10. The inner support has a circular cross-section and is dimensioned to fit loosely inside the pipe T. The inner support 9 includes a longitudinally movable wedge 11, which is configured to press the upper surface 9 of the inner support against the inner peripheral surface of the pipe T. The punch 1 is configured to be inserted into the punch hole 10 when the inner support 9 is disposed inside the pipe at the support position. Due to the round shape of the inner support (9), its upper surface abuts against the inner surface of the main pipe around the punch hole (10).

[0018] The inner support 9 is configured to be moved in and out of the support position by one actuator F. This actuator F is first configured to move the inner support 9 with the wedge 11 to the support position via the slider 13, the wedge arm 11a, and the spring 14. The force required for this movement is smaller than the force required to change the shape of the spring 14 against the spring force (compress the compression spring). In this case, the spring 14 functions as a fixed pin that pushes the fastener 12 of the inner support 9 forward. The wedge arm 11a is attached to the slider 13, and the slider 13 is moved back and forth by the actuator F. The actuator F is usually a piston cylinder device. In the illustrated example, two compression springs 14 are attached between the fastener 12 and the slider 13. The slider 13 is on a slide carriage 16 that moves on the linear guide 15. The linear guide 15 is supported by the frame 2 connected to the fixed restraint 19, and the inner support 9 can pass between the fixed restraints. The restraint 19 functions as an operation limiter for the inner support 9. When the fastener 12 collides with the restraint 19 of the frame, the actuator F moves only the wedge 11 via the slider 13 and the wedge arm 11a against the force of the spring 14, thereby wedge-fixing the inner support 9 in the support position. In this case, the inner support 9 is held in the support position by the fastener 12 leaning against the restraint 19. On the sides of the slider 13 and the fastener 12, there is a slide guide (not shown) attached to the frame 2 to support the structure formed by the fastener 12 and the slider 13.

[0019] The wedge 11 has a first wedge surface 11w and is arranged such that when the actuator F moves the wedge 11 relative to the inner support 9 from right to left in FIG. 2, the inner support 9 is pressed against the inner peripheral surface of the pipe. The movement of the wedge 11 continues until the inner support 9 contacts the inner peripheral surface of the pipe with sufficient force. When the inner support 9 is stationary inside the pipe at the support position, the punch 1 moves into the punch hole 10 of the inner support 9. After punching, the actuator F pulls the slider 13 and the wedge 11 in the opposite direction, so that the force of the spring 14 holds the inner support at a predetermined position until the wedge surface 11w has moved sufficiently and the inner support 9 is released from the support pressure. The second wedge surface 11b of the wedge 11 and the pin 18 of the inner support are arranged such that when the movement of the slider 13 continues from left to right, the wedge 11 is disengaged from contact with the inner peripheral surface of the pipe. A groove 17 is formed in the wedge 11, and the pin 18 of the inner support fits into this groove. The groove 17 and the pin 18 pull the inner support 9 backward from the support position. During the wedge driving stage, with the help of the wedge surface 11w, the groove 17 does not restrict the movement between the inner support 9 and the wedge 11, and the movement continues until the inner support hits the inner peripheral surface of the pipe with sufficient force. In this way, the free end of the wedge 11 extends below the expanding punch hole 10.

[0020] To drill a branch hole in the pipe, the punch 1 is guided by the guide hole 7 and operates at a right angle to the central axis of the pipe.

[0021] FIG. 4 shows the design of the end of the branch pipe P suitable for connecting to the hole 20 formed as described above by internal welding. The cutting depth and curvature of the portion 22 removed from the tip of the branch pipe P are adjusted such that the tip of the branch pipe P contacts the outer surface of the main pipe T just near the edge of the hole 20. In this case, an appropriate amount of material to be melted during welding is obtained at the joint.

[0022] By using the above-described apparatus, a hole can be drilled in the main pipe by the following method steps. - Move the main pipe (T) axially between the holding jaws 4 and 5 to the punching position of the main pipe. - Bring the holding jaws 4 and 5 into contact with the main pipe to hold the main pipe at the punching position. - Move the inner support 9 and the wedge 11 belonging to the inner support into the main pipe. - The moving operation of the inner support 9 stops at a position where the round punch hole 10 of the inner support hits within the orbit of the punch 1 of the hole formed in the main pipe. - The movement of the wedge 11 relative to the inner support 9 is continued to press the inner support against the inner wall of the main pipe (T) around the punch hole 10. - The punch 1 is guided by the guide hole 7 and moves towards the central axis of the main pipe, whereby the cutting edge 3 of the punch penetrates the wall of the main pipe T, and one solid part is removed from the hole 20 formed in the wall into the punch hole 10. - The wedge 11 is moved in the direction opposite to the previous moving direction to release the pressure on the inner peripheral surface of the main pipe from the inner support 9. - The inner support 9 and the wedge 11 are moved in the direction away from the inside of the main pipe. - The holding jaws 4 and 5 are opened, and the punched main pipe is released from the holding jaws 4 and 5.

[0023] The punched pipe must be removed from the holding jaws 4 and 5 using a special extractor 23 attached to the holding jaws. When the holding jaws 4 and 5 are moved in the direction of pulling away from each other, the hook-shaped extractor 23 pulls the pipe out of the support troughs 6 and 8.

[0024] Thus, the punch 1 is used to remove one solid part from the wall of the main pipe T. Two curved parts are also removed from the ends of the branch pipe P, and the curvature of its cutting surface corresponds to the curvature of the outer surface of the main pipe. Finally, the end of the formed branch pipe P is placed around the hole 20 of the main pipe, and the joint 21 between the pipes is welded by internal welding without using a welding additive, melting the material of the overlapping joint part to join them. Shown in Fig. 4 are the electrode arm 24 and the electrode 25, the tips of which are guided along a path along the joint 21 by moving back and forth simultaneously while rotating the electrode arm. A power source 26 is used to generate a voltage between the electrode 25 and the pipe. The voltage is adjusted so that the arc between the electrode 25 and the joint melts the material of the joint 21 to form one wall that fuses the walls of the pipes T and P.

Claims

1. A method of manufacturing a T-branch of a pipe by joining a formed end of a branch pipe to the edge of a hole in a main pipe by internal welding, wherein in the method, the arc corresponding to the hole in the main pipe (T) and the end of the branch pipe (P) is mechanically cut by dry machining by removing one solid part from the hole and two (22) solid parts from the end of the branch pipe, the cleanliness of the joint is maintained in a weldable state, and the main pipe is supported from the outside by holding jaws (4, 5), the main pipe is supported from the inside by an expandable inner support (9, 10, 11) around the hole to be cut, the hole (20) for the branch pipe is guided to the guide hole (7) of the second holding jaw (4) and cut by a punch (1) moving perpendicular to the central axis of the main pipe, the end of the formed branch pipe (P) is arranged around the hole in the main pipe (T), and the seam (21) between the pipes is welded by internal welding without a welding additive, method.

2. The method step of cutting a hole in the main pipe includes - moving the main pipe axially between the holding jaws (4, 5) to the punching position of the main pipe (T), - bringing the holding jaws (4, 5) into contact with the main pipe to hold the main pipe in the punching position, - moving the inner support (9) and the wedge (11) belonging to the inner support into the main pipe, - stopping the movement of the inner support (9) at a position where the round punch hole (10) of the inner support hits within the orbit of the punch (1) of the hole to be formed in the main pipe, - continuing the movement of the wedge (11) relative to the inner support (9) to press the inner support against the inner wall of the main pipe (T) around the punch hole (10), - the punch (1) is guided by the guide hole (7) and moves towards the central axis of the main pipe, whereby the cutting edge (3) of the punch penetrates the wall of the main pipe and one solid part is removed from the hole (20) formed in the wall into the punch hole (10), - the wedge (11) is moved in a direction opposite to the previous moving direction to release the pressure on the inner support (9) against the inner circumferential surface of the main pipe, - the inner support (9) and the wedge (11) are moved in a direction away from the inside of the main pipe, - the holding jaws (4, 5) are opened and the punched main pipe is released from the holding jaws (4, 5), including, the method according to claim 1.

3. The inner support (9) is pressed against the inner peripheral surface of the tube by a wedge (11), and the wedge moves back and forth relative to the inner support (9) by the same actuator (F) that moves the inner support (9) in and out of the support position. The inner support (9) first moves to the support position together with its wedge (11) via a wedge arm (11a) and a spring (14), and then moves to the support position by moving only the wedge (11) via the wedge arm (11a) against the force of the spring (14). The method according to claim 2.

4. An apparatus for making a branch hole in a tube by the method according to claim 2, wherein the apparatus comprises a punch (1) having a circular cross-section, a cutting edge (3) at the end of the punch, holding jaws (4, 5) for supporting the tube from the outside during punching, and includes the holding jaws comprising support troughs (6, 8) for receiving the tube to be punched, a punch guide hole (7) for receiving the punch (1) in a first part (4) of the holding jaws, the guide hole (7) having a central axis in the moving direction of the punch (1), which is perpendicular to the central axis of the cylinder formed by the surfaces of the support troughs 6, 8 in the tube support position, the apparatus further comprises an inner support (9) for supporting the tube from the inside during punching, the inner support including a round punch hole (10), the inner support (9) being movable in the longitudinal direction and including a wedge (11) configured to press the inner support (9) against the inner peripheral surface of the tube, the punch (1) being configured to be inserted into the punch hole (10) when the inner support (9) is placed in the support position inside the tube, the inner support (9) being designed such that its upper surface abuts against the inner peripheral surface of the main tube around the punch hole (10). Apparatus.

5. The cutting edge (3) of the punch (1) has a steel edge, the distance between the two lowest points thereof corresponding to the longitudinal length of the tube to be punched, The apparatus according to claim 4.

6. The inner support (9) is configured to be moved in and out of the support position by one actuator F. This actuator F first moves the inner support (9) with a wedge (11) to the support position via a wedge arm (11a) and a spring (14), and then is configured to move only the wedge (11) via the wedge arm (11a) against the force of the spring (14), so that the inner support (9) is wedged and fixed in the support position. The apparatus according to claim 4.

7. The wedge (11) has a first wedge surface (11w) configured to press the inner support (9) against the inner peripheral surface of the tube, and the other wedge surface (11b) configured to move the wedge (11) away from contact with the inner peripheral surface of the tube. The apparatus according to claim 4 or 6.

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