Method and device for producing T-branch for pipe

Abstract

The invention relates to a method and an apparatus for making a T-branch for a pipe by connecting a shaped end of a branch pipe to an edge of a hole in a main pipe using internal welding. The hole in the main pipe (T) and the arc corresponding to the main pipe at the end of the branch pipe (P) are mechanically cut by removing one solid portion from the hole and removing two (22) solid portions from the end of the branch pipe in a dry mechanical process, where the cleanliness of the joining area remains weldable. The shaped ends of the branch pipes (P) are placed around the holes in the main pipe (T), and the seams between the pipes are welded by internal welding without the use of welding additives. The branch hole suitable for this is made by punching perpendicularly with respect to the central axis of the main pipe such that the punched part (1) pushes the part separated from the main pipe into the punched hole (10) of the inner support part (9).

Description

Technical Field

[0001] The invention relates to a method and a device for producing a T-shaped branch for a pipe by connecting the shaped end of the branch pipe to the edge of a hole in the main pipe by means of internal welding.

[0002] The invention also relates to a device which can be used to make a hole in a main pipe as required by the method. The object of the invention is to retain a suitable amount of material around the hole in the main pipe for welding the parts together from the inside without introducing additional material from the outside. Background Art

[0003] For example, using the method and apparatus known from patent publication US 10537948, the end of the branch pipe is cut into an arc suitable for the main pipe.

[0004] When making a T-shaped branch of a tube, there are many ways to make the hole in the tube to make the branch joint. For relatively small tubes, the most common method is drilling. Drilling produces debris and effective drilling requires the use of cutting fluids. The debris and fluids are disadvantages in production and the environment because for butt welding, the debris must be removed and the parts must be cleaned, usually by washing with warm water. In addition, forming a hole in a tube by drilling is a relatively slow production method.

[0005] The simplest way to make a hole suitable for making a T-shaped branch is a punching method, in which the hole is punched with a circular punch perpendicular to the longitudinal axis of the tube. This works when the branch pipe is smaller than the main pipe by a certain amount. The present invention relates to such a case. In patent application FI 20217012, a perforation method and device for making an elliptical hole in the wall of a tube with a circular cross section are disclosed. The hole is used to make a T-branch collar by bending and stretching the edges of the hole into a collar. Summary of the invention

[0006] The object of the present invention is to provide a method and a device by means of which the mechanical working steps of the components of the T-shaped branch can be carried out as a "dry process" without cutting oils and washing liquids, making it possible to form a hole in the main pipe by using a punching method and a device suitable for this punching method, and the shaped end of the branch pipe, which is smaller than the main pipe, can be directly connected to the edge of the hole by means of internal welding.

[0007] In the method according to the invention, the hole in the main pipe (T) and the arc corresponding to the main pipe at the end of the branch pipe (P) are mechanically cut by removing one solid part from the hole and two solid parts from the end of the branch pipe in a dry mechanical process, wherein the cleanliness of the joining area is maintained to be weldable, the main pipe is supported from the outside by holding jaws, the main pipe is supported from the inside around the hole to be cut by an expandable internal support, the hole for the branch pipe is cut using a punch, the punch is moved vertically against the central axis of the main pipe and guided by a guide hole in a second holding jaw, the formed end of the branch pipe (P) is placed around the hole in the main pipe (T), and the seam between the pipes is welded by internal welding without using welding additives.

[0008] Examples of methods and devices for performing internal welding are disclosed in publications US 6433307 (B1), EP 1633520 (B1), and WO 2019166689. Based on these, a person skilled in the art can use the present invention in terms of features related to internal welding.

[0009] In the device according to the invention, a specially constructed internal support is used to prevent the shape of the main tube from changing when the punching member penetrates the wall of the main tube into the punched hole of the internal support. The device is characterized by what is presented in claim 4.

[0010] When the branch pipe is a certain amount smaller than the main pipe, the edge shape of the hole in the main pipe can be matched to the shape of the inner surface of the end of the branch pipe, so that the overlapping material thickness of the joint is suitable for welding the parts together from the inside without introducing any additives from the outside.

[0011] Preferred embodiments of the invention are disclosed in the dependent claims and in the device claim. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the following, the invention will be explained with the aid of exemplary embodiments with reference to the accompanying drawings, in which:

[0013] Figure 1 The essential components of a device for carrying out the method according to the invention are shown from below.

[0014] Figure 2 Shows from Figure 1 A cross section taken along line AA with the frame 2, linear guide 15 and sliding bracket 16 added.

[0015] Figure 3 Shown according to Figure 1 End view of the device.

[0016] Figure 4 A tubular T-shaped branch produced by the method and device according to the invention is shown. DETAILED DESCRIPTION

[0017] The branch hole 20 ( Figure 4 ) is punched into the main pipe T, the cross section of the punch 1 is circular. The cutting blade 3 of the punch 1 has a steel edge, the two lowest points of which are at a distance from each other corresponding to the longitudinal direction of the pipe to be punched ( Figure 2 ). In this case, the cutting force is not directed as an impact but as a cut, and the separated parts are shaped and separated in a controlled manner.

[0018] During the punching process, the tube is supported from the outside by means of holding jaws 4, 5. The holding jaws 4, 5 comprise a holding groove 6, 8 for receiving the tube to be punched. The curvature of the holding groove corresponds to the curvature of the outer surface of the main tube T. In the main tube supporting position, the holding jaws 4, 5 remain slightly spaced apart from each other. The second holding jaw 5 can be moved forwards and backwards so that the tube can be placed between the holding jaws 4, 5 in the clamping grip of the groove 6, 8.

[0019] The first part 4 of the holding jaws has a stamping guide hole 7 for receiving the stamping 1. The guide hole 7 has a center axis in the moving direction of the stamping 1, which is perpendicular to the center axis of the cylinder formed by the surfaces of the support grooves 6, 8 in the tube support position. In this case, when the tube T is located between the holding jaws 4, 5 and supported by the support grooves 6, 8 in the tube support position, the center axis of the stamping 1 is oriented perpendicular to the center axis of the tube T.

[0020] The punching device also includes an internal support 9 for supporting the main pipe T from the inside during the punching process. When the punch penetrates the wall, in the case of cutting, the internal support is required to prevent the main pipe T to be cut from deforming. The internal support has a punch hole 10, which accommodates the punch 1 and expands downward to allow the separated parts to fall out of the internal support when the internal support 9 is pulled out of the pipe. The internal support 9 must support the pipe close to the outer edge of the punch 1, that is, around the punch hole 10 in close proximity. The cross-section of the internal support is circular and is sized to fit loosely in the pipe T. The internal support 9 includes a longitudinally movable wedge 11, which is arranged to press the upper surface 9 of the internal support against the inner surface of the pipe T. The punch 1 is arranged to be inserted into the punch hole 10 when the internal support 9 is in place inside the pipe in the supporting position. Due to the circular shape of the inner support (9), its upper surface abuts against the inner surface of the main pipe around the punched hole (10).

[0021] The inner support 9 is arranged to be moved into and out of the support position by an actuator F, which is arranged to first move the inner support 9 together with the wedge 11 to the support position via the slide 13, the wedge arm 11a and the spring 14. The force required for this movement is less than the force required to change the shape of the spring 14 (compress the compression spring) against the spring force, which in this case acts as a fixing pin for the fastener 12 that pushes the inner support 9 forward. The wedge arm 11a is attached to the slide 13, which is moved back and forth by the actuator F. The actuator F is typically a piston-cylinder device. In the case shown, two compression springs 14 are attached between the fastener 12 and the slide 13. The slide 13 is located on top of a sliding carriage 16 that moves on a linear guide 15. The linear guide 15 is supported on the frame 2, which is connected to fixed constraints 19, between which the inner support 9 can pass. The constraints 19 act as movement limiters for the inner support 9. When the fastener 12 collides with the constraint 19 of the frame, the actuator F moves only the wedge 11 via the slide 13 and the wedge arm 11a against the force of the spring 14, whereby the inner support 9 is wedged into the supporting position. In this case, the inner support 9 is held in the supporting position by the fastener 12 tilted against the constraint 19. On the sides of the slide 13 and the fastener 12, there is a sliding guide (not shown in the figure) attached to the frame 2, which supports the structure formed by the fastener 12 and the slide 13.

[0022] The wedge 11 has a first wedge surface 11w, which is arranged to be in a position where the actuator F moves the wedge 11 relative to the inner support 9. Figure 2The wedge 11 continues to move until the internal support 9 is against the inner surface of the tube with sufficient force. When the internal support 9 is stationary in the tube in the supporting position, the punch 1 moves into the punch hole 10 in the internal support 9. After punching, the actuator F pulls the slide 13 and the wedge 11 in opposite directions, whereby the force of the spring 14 holds the internal support in place until the wedge surface 11w moves sufficiently to release the internal support 9 from the supporting pressure. The second wedge surface 11b of the wedge 11 and the pin 18 of the internal support are arranged to lift the wedge 11 out of contact with the inner surface of the tube when the slide 13 continues to transfer from left to right. The wedge 11 has a groove 17 into which the pin 18 of the internal support extends. With the help of the groove 17 and the pin 18, the wedge 11 pulls the internal support 9 backward away from the supporting position. During the wedging phase, the groove 17 does not restrict the movement between the inner support 9 and the wedge 11 by means of the wedge surface 11w, which continues until the inner support abuts against the inner surface of the tube with sufficient force. In this way, the free end of the wedge 11 extends into the enlarged lower part of the punch hole 10.

[0023] In order to make the branch hole reach the tube, the punching piece 1 is guided by the guide hole 7 to extend perpendicularly to the central axis of the tube.

[0024] Figure 4 The design of the end of the branch pipe P is illustrated so that it is suitable for connection by internal welding to the hole 20 formed as described above. The cutting depth and curvature of the part 22 to be removed from the end of the branch pipe P are adjusted so that the end of the branch pipe P is located on the outer surface of the main pipe T, next to the edge of the hole 20. In this case, a suitable amount of material to be melted during welding is obtained at the joint.

[0025] By using the above device, a hole can be cut in the main pipe by the following method steps:

[0026] - Bringing the main tube in its axial direction between the retaining jaws 4 , 5 to the punching position (T) of the main tube;

[0027] - bringing the retaining jaws 4 , 5 into contact with the main tube to hold it in the punching position;

[0028] - moving the internal support 9 and the wedge 11 belonging to the internal support into the main pipe;

[0029] - stopping the transfer movement of the internal support 9 at the point where the circular punched hole 10 in the internal support is located in the trajectory of the punch 1 at the hole to be formed in the main pipe;

[0030] - continuing the movement of the wedge 11 relative to the internal support 9 so as to press it against the inner wall of the main tube (T) around the punched hole 10;

[0031] - the punch 1 is guided by the guide hole 7 towards the central axis of the main tube, whereby the cutting blade 3 of the punch pierces the wall of the main tube T and removes a solid part from the hole 20 produced in the wall into the punch hole 10;

[0032] - moving the wedge 11 in a direction opposite to the previous direction of movement, so as to release the internal support 9 from the pressure on the inner surface of the main pipe;

[0033] - Move the inner support 9 and the wedge 11 away from the interior of the main pipe;

[0034] - Open the holding jaws 4 , 5 and release the punched main tube from the holding jaws 4 , 5 .

[0035] The punched tube must be removed from the holding jaws 4, 5 with a special extractor 23 attached to the holding jaws. The hook-like extractor 23 pulls the tube out of the support grooves 6, 8 when the holding jaws 4, 5 are moved away from each other.

[0036] Thus, the punch 1 is used to remove a solid portion from the wall of the main pipe T. Two bends are also removed from the end of the branch pipe P, the curvature of the cut surface of the branch pipe P corresponding to the curvature of the outer surface of the main pipe. Finally, the shaped end of the branch pipe P is placed around the hole 20 of the main pipe, and the seam 21 between the pipes is welded without welding additives using internal welding, fusing the material of the overlapping joint edges together. Figure 4 2 and 3. Shown in the figure are an electrode arm 24 and an electrode 25, the tip of the electrode arm 24 being guided along a path following the joint 21 by rotating the electrode arm and simultaneously moving it back and forth. A power supply 26 is used to generate a voltage between the electrode 25 and the tube. The voltage is adjusted so that the arc between the electrode 25 and the joint melts the material of the joint 21 into one wall that fuses with the wall of the tube T, P.

Claims

1. A method of making a T-shaped branch for a pipe by connecting the shaped end of the branch pipe to the edge of a hole in the main pipe by internal welding, in which method the hole in the main pipe (T) and the arc corresponding to the main pipe at the end of the branch pipe (P) are mechanically cut by removing one solid part from the hole and two (22) solid parts from the end of the branch pipe in a dry mechanical process, wherein The cleanliness of the joining area is maintained to be weldable, the main pipe is supported from the outside by means of retaining jaws (4, 5), the main pipe is supported from the inside around the hole to be cut by means of expandable internal supports (9, 10, 11), the hole (20) for the branch pipe is cut by means of a punch (1), the punch (1) moves perpendicularly to the central axis of the main pipe, the punch (1) is guided by a guide hole (7) in a second retaining jaw (4), the formed end of the branch pipe (P) is placed around the hole in the main pipe (T), and the joint (21) between the pipes is welded by internal welding without using welding additives.

2. The method according to claim 1, wherein: The hole in the main pipe is cut by the following method steps: - Bringing the main tube in the axial direction of the main tube between the holding jaws (4, 5) to a punching position of the main tube (T); - bringing the retaining jaws (4, 5) into contact with the main tube in order to retain the main tube in the punching position; - moving the internal support (9) and the wedge (11) belonging to it into the main pipe; - stopping the transfer movement of the internal support (9) in a position where the circular punched hole (10) in the internal support is located on the trajectory of the punch (1) at the hole to be formed in the main pipe; - continuing the movement of the wedge (11) relative to the internal support (9) so as to press the internal support against the inner wall of the main tube (T) around the punched hole (10); - guiding the punch (1) to move towards the central axis of the main pipe, guided by the guide hole (7), whereby the cutting blade (3) of the punch pierces the wall of the main pipe and removes a solid part from the hole (20) produced in the wall into the punch hole (10); - moving the wedge (11) in a direction opposite to the previous direction of movement in order to release the pressure of the internal support (9) against the inner surface of the main pipe; - moving the inner support (9) and the wedge (11) away from the interior of the main pipe; - Opening the holding jaws (4, 5) and releasing the punched main tube from the holding jaws (4, 5).

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

4. A device for forming a branch hole in a tube by the method according to claim 2, wherein: The device comprises a punching part (1), a cutting blade (3), a plurality of retaining jaws (4, 5) and an internal support member (9), wherein the punching part (1) has a circular cross section, the cutting blade (3) is at the end of the punching part, the plurality of retaining jaws (4, 5) are used to support the tube from the outside during the punching process, the retaining jaws (4, 5) comprise a plurality of support grooves (6, 8) and a punching guide hole (7) in the first part (4) of the retaining jaws, the plurality of support grooves (6, 8) are used to receive the tube to be punched, the punching guide hole (7) receives the punching part (1), the guide hole (7) has a central axis in the moving direction of the punching part (1), the central axis is perpendicular to the support member (9) provided by the support member (9). The surface of the groove (6, 8) forms a tube support position of the central axis of the cylinder, the internal support (9) supports the tube from the inside during punching, the internal support includes a circular punching hole (10), characterized in that the internal support (9) includes a wedge (11) that can move in the longitudinal direction, the wedge (11) is arranged to press the internal support (9) against the inner surface of the tube, and the punching member (1) is arranged to be inserted into the punching hole (10) when the internal support (9) is in place inside the tube in the supporting position, and the internal support (9) is designed so that the upper surface of the internal support (9) abuts against the inner surface of the main tube surrounding the punching hole (10).

5. The device according to claim 4, characterized in that The cutting blade (3) of the punch (1) has a steel edge, the two lowest points of which are at a distance from each other corresponding to the longitudinal direction of the tube.

6. The device according to claim 4, characterized in that The internal support (9) is arranged to be moved into and out of the supporting position by an actuator (F), and the actuator (F) is arranged to first move the internal support (9) together with the wedge (11) of the internal support (9) to the supporting position via the wedge arm (11a) and the spring (14) and then move only the wedge (11) via the wedge arm (11a) against the force of the spring (14), whereby the internal support (9) is wedged into the supporting position.

7. The device according to claim 4 or 6, characterized in that The wedge (11) has a first wedge surface (11w) arranged to press the inner support against the inner surface of the tube and a further wedge surface (11b) arranged to lift the wedge (11) from the inner surface of the tube.

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