Method for connecting a tapping saddle and tapping saddle

Abstract

Method for connecting a tapping fitting to a pipeline (4), wherein the tapping fitting has a slidably mounted punch sleeve (6) having a projection (26) on its inner surface and a slidably mounted mandrel (10), wherein the mandrel and the punch sleeve are slidably independent of each other, wherein the method comprises the following steps: a. Positioning the tapping saddle on the pipeline (4), b. Moving the mandrel (10) towards the pipe (4) until the mandrel (10) penetrates the pipe (4), c. Moving the punch sleeve (6) towards the pipe (4) until the punch sleeve (6) pierces the pipe (4) so ​​that a plug (24) is punched out of the pipe (4), with the mandrel (10) already passing through the plug (24), d. Moving the mandrel (10) away from the pipe (4) so ​​that the plug (24) is moved with the mandrel (10), e. Moving the mandrel (10) and the plug (24) towards the pipe (4) so ​​that the plug (24) rests against the projection (26) and the mandrel (10) is pushed through the plug (24) and f. Moving the mandrel (10) and the plug (24) away from the pipe (4).

Description

[0001] The invention relates to a method for connecting a tapping saddle to a pipeline. The invention also relates to a tapping saddle usable for such a method.

[0002] Tapping saddles are a well-established technology used when a branch needs to be added to an existing pipeline, for example, to create a new connection. The pipeline typically carries a fluid, such as water or gas. Tapping saddles are used to access the pipeline so that a new branch or connection can be created without shutting down the pipeline. This ensures that the supply to downstream consumers is not interrupted, and the branch or connection can be installed quickly, easily, and cost-effectively.

[0003] This requires tapping into the pipeline, which is typically a plastic pipeline. DE 10 2005 008 398 A1 describes such a tapping saddle, which includes a drill bit. To begin tapping the pipeline, the tapping saddle is first firmly positioned on the pipeline, for example, using a pipe clamp. The drill bit is then placed on the outside of the pipeline and rotated. It has a hollow cutting head that moves along a circular path through the pipe wall until it penetrates the pipe. "Puncture" the pipeline in this context means that the pipe wall is breached, creating a connection between the inside of the pipeline and the outside.A disadvantage of using such a drill bit is that drilling can produce chips which are carried along with the fluid flowing in the pipeline and could thus be directed to a consumer of the fluid, where they can lead to blockages or contamination or even damage to equipment.

[0004] To solve this problem, DE 10 2006 029 297 A1 proposes equipping a drill bit with a chamber that is moved out of the drilled pipe, thus removing the plug drilled out of the pipe wall and any resulting chips from the fluid flowing in the pipe. However, a disadvantage is that even in this design, the drill bit remains in the drilled pipe, increasing the flow resistance to the connecting pipe. Furthermore, after drilling, the connection between the drive element of the drill bit and the cutting element remaining in the borehole must be disconnected. Otherwise, the cutting element would be unscrewed along with the drive element when it is withdrawn from the fluid flow. This is technically disadvantageous, or at the very least, time-consuming.

[0005] From DE 196 29 459 A1, a tapping saddle is known that does not have a drill bit but rather a punched sleeve that is forced through the pipe wall by applying high pressure. This significantly reduces the risk of chip formation. The resulting plug is flushed out through the outlet port, which every tapping saddle has and which is connected to a pipeline leading to the new customer. A disadvantage is that the saddle must be flushed before connecting a branch line. In practice, however, the branch line is often laid first, and only then is the connection to the pipeline drilled, making flushing difficult. Furthermore, this design requires a minimum line pressure in the tapped pipeline to overcome the friction between the punched sleeve and the plug.

[0006] From WO 2017 / 141016 A2 and US 5 964 240 A, tapping fittings are known in which a mandrel is provided that pierces the plug when the punch sleeve cuts the plug out of the pipe.

[0007] The invention is therefore based on the objective of proposing a method for connecting a tapping fitting to a pipeline and a tapping fitting suitable for this purpose, with which the disadvantages of the prior art are avoided, or at least mitigated.

[0008] The invention solves the stated problem by a method for connecting a tapping fitting to a pipeline, wherein the tapping fitting has a slidably mounted punch sleeve having a projection on its inner surface and a slidably mounted mandrel, wherein the mandrel and the punch sleeve are slidably independent of each other, wherein the method comprises the following steps: a. Positioning the tapping saddle on the pipeline, b. Moving the mandrel towards the pipeline until the mandrel pierces the pipeline, c. Moving the punch sleeve towards the pipeline until the punch sleeve pierces the pipeline, so that a plug is punched out of the pipeline, with the mandrel already passing through the plug, d. Moving the mandrel away from the pipe so that the plug is moved with the mandrel, e. Moving the mandrel and plug towards the pipeline so that the plug rests against the projection and the mandrel is pushed through the plug and f. Moving the mandrel and plug away from the pipe.

[0009] After the tapping saddle has been positioned on the pipeline and preferably permanently secured, the mandrel is first moved towards the pipeline until it pierces it. This occurs when the tip of the mandrel is inside the pipeline. In other words, the mandrel penetrates the pipe wall. Only then is the punch sleeve also moved towards the pipeline until it pierces it. The punch sleeve is hollow and has a punching edge with which it pierces the pipeline. In doing so, a section is punched out of the pipe wall. This section is referred to as the plug. The mandrel passes through this plug. Consequently, the mandrel has pierced the pipe wall at a point corresponding to the plug. In a preferred embodiment, the mandrel runs inside the punch sleeve and can be moved relative to it.

[0010] It is not necessary for the punch sleeve to remain stationary until the mandrel has pierced the pipe. The only important thing is that the punch sleeve only punches the plug out of the pipe wall once the mandrel has already pierced the pipe wall and thus the pipe itself. If the plug were no longer connected to the pipe wall because it had already been separated by the punch sleeve, it could no longer be pierced by the mandrel due to insufficient counterforce, and would instead be pushed into the pipe. Because the mandrel first pierces the pipe and thus the future plug before the punch sleeve punches the plug out of the pipe wall, it is ensured that the plug is not carried away by the fluid flowing through the pipe. Rather, it remains securely attached to the mandrel.

[0011] Preferably, when the mandrel is subsequently moved away from the pipeline, it is moved until the plug no longer makes contact with the punch sleeve. During this movement, the punch sleeve preferably remains in the pipeline, and the mandrel is also moved relative to the punch sleeve. Preferably, the mandrel is moved away from the pipeline, and thus also from the punch sleeve, until it is located outside the punch sleeve. This allows fluid from the drilled pipeline to flow through the punch sleeve into a branch line, which is, for example, connected to an outlet of the tapping saddle.

[0012] According to the invention, the die sleeve has a projection on its inner surface, which is preferably a circumferential projection. The method preferably comprises the following additional steps: g. Moving the mandrel and plug towards the pipeline so that the plug rests against the projection and the mandrel is pushed through the plug, h. Moving the mandrel and the plug away from the pipeline.

[0013] In process step d., the mandrel, with the plug through which it extends, is moved away from the pipeline. This preferably occurs until the plug passes the projection on the inner surface of the punch sleeve. The projection is designed such that the inner diameter of the punch sleeve on the side of the projection facing the punching edge and thus the pipeline is smaller than the inner diameter of the punch sleeve on the side of the projection facing away from the punching edge and thus the pipeline. During the punching process, stresses arise in the material, leading to expansion of the plug as soon as the plug is no longer chambered along the cut edge. If, in process step d., the mandrel and the plug are moved until the plug passes this projection, the plug material is relieved of stress and expands along its circumference, so that when the mandrel is moved in process step e., the plug rests against the projection.If the overall expansion is insufficient, this function is achieved by friction of the plug against the inner wall of the cutting sleeve. Preferably, the plug cannot be moved past the projection towards the punching edge of the die. However, since the mandrel is moved beyond this point, it passes through the plug. Subsequently, the mandrel with the plug is moved away from the pipeline again. This moves the plug further out of the flow path of the fluid, so that the flow resistance caused by the plug is reduced, preferably completely eliminated.

[0014] The invention further solves the stated problem by means of a tapping fitting for a method described herein, wherein the tapping fitting comprises a slidably mounted punch sleeve, which is hollow and has a punching edge for piercing a pipeline, and a slidably mounted mandrel, wherein the mandrel and the punch sleeve are slidably independent of each other, wherein the punch sleeve has a projection on its inner surface, which is designed such that a plug punched out of the pipeline by the punch sleeve cannot be displaced past the projection towards the punching edge of the punch sleeve. The mandrel and / or the punch sleeve can be manually displaceable. For this purpose, preferably an actuating element is provided for each, onto which a force can be manually applied. Alternatively or additionally, at least one drive is provided by which the punch sleeve and / or the mandrel can be moved.Particularly preferred are two drives, one of which is configured to move the punch sleeve and the other of which is configured to move the mandrel.

[0015] Preferably, the punch sleeve and the mandrel are mounted so that they can slide parallel to each other. This means that the punch sleeve and the mandrel can slide in the same direction, i.e., the directions of movement are parallel. Since the process requires moving the punch sleeve and the mandrel towards and away from the pipeline, both the punch sleeve and the mandrel are movable back and forth along their respective directions of movement.

[0016] Preferably, the mandrel has a shaft and a head with a point, the head having a diameter that increases from the point and is larger at its greatest extent than the diameter of the shaft. The shaft can also be called a bolt, rod, or bar and preferably has a constant diameter along its length. It is particularly preferably circular in cross-section. The head of the mandrel is positioned on the shaft such that the point of the head faces away from the shaft and forms the point where the mandrel makes initial contact with the pipeline. The point is designed to penetrate the pipeline wall particularly well. Since the pipeline is preferably made of a plastic, the penetration of the mandrel's point causes elastic deformation.This does not mean that only elastic deformation occurs; plastic deformation is also possible. Due to the elastic component of the deformation, the opening in the pipe wall, created by the head of the mandrel, closes tightly around the mandrel's shaft as soon as the mandrel's tip has completely penetrated the pipe wall. This ensures that the pipe plug, which forms after the mandrel has passed through the pipe and through which the mandrel passes, cannot be separated from the mandrel when the mandrel is moved away from the pipe. Rather, the plug and mandrel are moved away from the pipe together.

[0017] In a preferred embodiment, the shaft of the mandrel has a step, wherein the diameter of the shaft on the side of the step facing the tip of the mandrel is larger than on the side of the shaft facing away from the tip.

[0018] Preferably, the punch sleeve has a rotationally symmetrical cross-section, with the mandrel extending along the axis of rotation.

[0019] According to the invention, the punch sleeve has a projection on its inner surface, which is preferably a circumferential projection. The projection is preferably designed such that the inner diameter of the punch sleeve on the side facing the punching edge is smaller than on the side facing away from the punching edge. The punching edge of the punch sleeve is the front end of the punch sleeve, which is the first part to come into contact with the pipeline when the punch sleeve is moved towards the pipeline.

[0020] In process step e., the mandrel with the attached plug is moved back towards the pipeline, with the plug, at a certain point, resting against the projection on the inner surface of the punch sleeve. The mandrel is then moved further towards the pipeline, so that it moves relative to the plug, which is prevented from also moving towards the pipeline by the projection. The mandrel continues to move through the plug. In other words, the plug is moved further away from the tip of the mandrel along the mandrel. This preferably continues until the step along the mandrel's shaft has also moved through the plug. Since, as already explained, the plug is also elastically deformed, the opening in the plug, through which the mandrel extends, closes tightly around the mandrel's shaft.This means that the diameter of the opening in the plug also decreases as soon as the step of the mandrel's shaft has moved through the plug. This makes it difficult or even impossible for the plug to move back over the step towards the tip of the mandrel. This is advantageous because, in process step f, the mandrel is moved away from the pipeline again, and this movement is also transferred to the plug. The plug is then moved further away from the flow path of the fluid flowing through the pipeline and also through the tapping saddle, so that the flow resistance caused by the plug is reduced or completely eliminated.

[0021] With the aid of the accompanying drawings, an embodiment of the present invention will be explained in more detail below. The drawings show... Fig. 1 to 5 - a tapping fitting according to the present invention in various stages of the process and Fig. 6 - the illustration of a die-cutting sleeve.

[0022] Fig. Figure 1 shows a tapping saddle according to an embodiment of the present invention. It is mounted by a clamp 2 on a pipeline 4, which is to be tapped. The tapping saddle has a punched sleeve 6 which is longitudinally displaceable, in Fig. The clamp 2 is arranged from top to bottom and vice versa. Between the upper part of the clamp 2 and the pipe 4 are sealing rings 8, which seal the gap so that the fluid closing in the pipe 4 cannot escape. The tapping saddle also has a mandrel 10, which is also longitudinally displaceable, i.e., arranged from top to bottom. The mandrel 10 has a tip 12 and a shaft 14, which has a step 16. It can be seen that the diameter of the shaft 14 changes at the step 16. On the side of the step 16 facing the tip 12, the diameter is larger than on the side of the step 16 facing away from the tip 12. Actuators 18 are located in the upper part of the tapping saddle, with which the mandrel 10 and the punch sleeve 6 can be moved. The tapping fitting also has an outlet nozzle 20, through which the fluid can flow out of the tapping fitting after the pipe 4 has been tapped. Fig. Figure 1 shows the situation after the tapping fitting is attached to the pipe 4 by the clamp 2.

[0023] In Fig. In step 2, both the mandrel 10 and the punch sleeve 6 were moved downwards, i.e., towards the pipe 4. First, the mandrel 10 is moved until its tip 12 has penetrated the wall of the pipe 4. Then, the punch sleeve 6 is moved, its punching edge 22 engaging in Fig. 1 and Fig. 2, also at its lower edge, punches a plug 24 out of the wall of the pipe 4, through which the mandrel 10 extends. It is important that the entire tip 12 of the mandrel 10 is located inside the pipe 4, so that the widest part of the tip is also inside the pipe 4. This acts like a barb on the plug 24.

[0024] In Fig. Figure 3 shows the situation after the next process step. The mandrel 10 has been moved away from the pipeline with the plug 24, i.e., upwards in the figures. This allows a flow path from the pipeline 4 through the punch sleeve 6 and the outlet nozzle 20, so that fluid can exit the pipeline 4 and enter the branch line, which is attached to the outlet nozzle 20 but not shown. However, it can be seen in Fig. 3, that the plug 24 severely restricts the free cross-section of the flow path and thus leads to a large flow resistance. It can be seen in Fig. 3. Furthermore, it is particularly advantageous that the die sleeve 6 has a projection 26, which is formed as a circumferential projection in the figures. The inner diameter of the die sleeve 6 changes at the projection 26. In the first region of the die sleeve 6, which faces the die edge 22, the die sleeve 6 has a smaller inner diameter than in the second region of the die sleeve 6, which faces away from the die edge 22.

[0025] In Fig. Figure 4 shows the situation after process step e. The mandrel 10, along with the plug 24, has been moved back towards the pipe 4. In doing so, the plug 24 has come into contact with the projection 26. The restoring forces of the pipe 4 wall material cause the plug 24 to expand, preventing it from penetrating the first section of the punch sleeve 6. However, as the mandrel 10 continues to move towards the pipe 4, it advances until the step 16 of the mandrel 10 has also penetrated the plug 24.

[0026] The mandrel 10 is then moved away from the pipe 4, which also moves the plug 24. It rests against the step 16 of the mandrel 10 and is thus moved significantly further away from the pipe 4, i.e., upwards in the figures, as is the case after process step d. Fig. 3 can be seen. The plug 24 now has a significantly smaller influence on the medium flowing from the pipeline 4 through the punch sleeve 6 and the outlet nozzle 20, so that a significantly lower flow resistance is achieved.

[0027] Fig. Figure 6 shows a schematic representation of a punch sleeve 6. The projection 26, where the inner diameter of the punch sleeve 6 changes, is visible on its inner wall. At the lower end of the punch sleeve 6 is the punching edge 22, which is circular in the illustrated embodiment. Projections 28 are shown on the outside of the punch sleeve 6. These projections allow the punch sleeve 6 to penetrate the pipe 4 when it is moved towards the pipe 4, but prevent it from being pulled out of the pipe 4. Reference symbol list: 2 bells 4 Pipeline 6 Punch sleeve 8 sealing ring 10 Dorn 12 top 14 shaft Level 16 18 Drive 20 outlet nozzles 22 Die-cut edge 24 plugs 26 lead 28 lead

Claims

[1] Method for connecting a tapping fitting to a pipeline (4), wherein the tapping fitting has a slidably mounted punch sleeve (6) having a projection (26) on its inner surface and a slidably mounted mandrel (10), wherein the mandrel and the punch sleeve are slidably independent of each other, wherein the method comprises the following steps: a. Positioning the tapping saddle on the pipeline (4), b. Moving the mandrel (10) towards the pipe (4) until the mandrel (10) penetrates the pipe (4), c. Moving the punch sleeve (6) towards the pipe (4) until the punch sleeve (6) pierces the pipe (4) so ​​that a plug (24) is punched out of the pipe (4), with the mandrel (10) already passing through the plug (24), d. Moving the mandrel (10) away from the pipe (4) so ​​that the plug (24) is moved with the mandrel (10), e. Moving the mandrel (10) and the plug (24) towards the pipe (4) so ​​that the plug (24) rests against the projection (26) and the mandrel (10) is pushed through the plug (24) and f. Moving the mandrel (10) and the plug (24) away from the pipe (4). [2] Method according to claim 1, characterized by , that in step d. the mandrel (10) is moved so far away from the pipe (4) that the plug (24) no longer has contact with the punch sleeve (6). [3] Method according to claim 1 or 2, characterized by , that the advantage (26) is a circumferential advantage (26). [4] Tapping fitting for a method according to claim 1, 2 or 3, wherein the tapping fitting has a slidably mounted punch sleeve (6) which is hollow and has a punch edge (22) for piercing a pipeline (4), and a slidably mounted mandrel (10), wherein the mandrel (10) and the punch sleeve (6) are slidably independent of each other, wherein the punch sleeve (6) has a projection (26) on its inner surface which is designed such that a plug (24) punched out of the pipeline (4) by the punch sleeve (6) cannot be displaced past the projection in the direction of the punch edge (22) of the punch sleeve (6). [5] Tapping fitting according to claim 4, characterized by , that the punch sleeve (6) and the mandrel (10) are mounted so as to be slidable parallel to each other. [6] Tapping fitting according to claim 4 or 5, characterized by , that the mandrel (10) and the punch sleeve (6) are displaceable along the longitudinal direction of the punch sleeve (6). [7] Tapping fitting according to any one of claims 4 to 6, characterized by , that the mandrel (10) has a shaft (14) and a head with a tip (12), the head having a diameter increasing from the tip (12) which at its greatest extent is larger than the diameter of the shaft (14). [8] Tapping fitting according to claim 7, characterized by , that the shaft (14) of the mandrel (10) has a step (16), wherein the diameter of the shaft (14) on the side of the step (16) facing the tip (12) of the mandrel (10) is larger than on the side of the step (16) facing away from the tip (12). [9] Tapping fitting according to any one of claims 4 to 8, characterized by , that the punch sleeve (6) has a rotationally symmetrical cross-section and the mandrel (10) extends along the axis of rotation. [10] Tapping fitting according to any one of claims 4 to 9, characterized by, that the projection (26) is a circumferential projection (26) which is preferably designed such that an inner diameter of the punch sleeve (6) on the side of the projection (26) facing the punching edge (22) is smaller than on the side of the projection (26) facing away from the punching edge (22).

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