Patent Application
20230258292
The present invention relates to devices for repairing pipelines, pipes, and ducts intended to transport fluids or gas under pressure and relates in particular to a sealing device for plugging a leak in the wall of a pipe or tank, comprising a drilling part and a tapping part, and sealing method.
Pipelines or pipes transporting gas or liquid under pressure over long distances are subject to damage such as internal and external corrosion, impact or sabotage. It often happens that the pipe is damaged to the point of causing a leak of its contents due to the formation of a crack or hole. Repair solutions have been developed to stop these local leaks, for example, by welding a steel plate at the location of the hole. However, this solution has the disadvantages of using heavy equipment and taking a long time to implement. On the other hand, its material and labor cost is high, and sometimes its implementation is impossible in certain closed places. Another solution is to apply a steel plate wrapped with composite over the hole. The implementation of this solution is delicate, and its reliability is uncertain because it depends on the ambient temperature and the materials, which makes it very difficult to achieve on a submerged pipe.
The solution consisting in sealing by applying a mastic can be used on pipes under low pressure and is temporary.
Finally, one solution is to install a threaded plug. However, this requires having a perfectly circular hole and tapping aligned with the axis of the hole. Tapping, usually carried out after the drilling step, needs to be perfectly aligned and centered on the drilling axis. In addition, the plug must then be gently introduced so as to avoid cross-threading resulting in a leak path along the threads. Such damage represents an additional difficulty in the case of a pressurized and submerged pipe.
A prior art pipe plug described in document EP0951626 comprises a self-tapping part which allows, during the installation of the plug in the conical hole in which it is inserted, to create a thread on the inner wall of the hole. At its end, the plug comprises sealing rings whose diameter is smaller than the decreasing initial diameter of the conical hole in which the plug is inserted. The sealing rings come into contact with the inner wall of the hole as the plug head approaches its position against the pipe. Such a plug requires a conical hole to be drilled in advance to the dimensions of the plug.
The document JPH09210285A describes a device for sealing a leakage hole comprising a self-tapping screw adapted to be screwed into the leakage hole when tapped with a hammer and provided with a cylindrical seal. This solution has the disadvantage of requiring extensive resources in the case of a pressurized and submerged pipe.
This is why the object of the invention is to overcome the aforementioned drawbacks by providing a sealing device comprising a plug, a tap and a drill.
Another object of the invention is to provide a method of sealing a leak in the wall of a pipe or tank performed in a single step.
The object of the invention is, therefore, a sealing device with a longitudinal axis (Z, Z′) for plugging a leak in the wall of a pipe or tank further comprising a drive means at one end, a plug and a tap, the device comprising at its other end a drilling head adapted to drill a cylindrical hole in the thickness of the wall of the pipe at the location of the leak, the tap creating threads on the inside of the smooth walls of the cylindrical hole. According to the main characteristics, the plug comprises a thread and a thread runout chamfer on which the thread ends, the end of the thread extending over a clearance groove and a smooth upper chamfer suitable for deforming the thread at the internal thread end, said hole being intended to be sealed by the plug.
Advantageously, the device according to the invention is installed in the wall of a pipe at the location of the opening causing a leak, in a single operation which includes drilling [a hole] in the thickness of the wall of the pipe, tapping and installing a threaded plug in the drill hole. On the other hand, the device comprises means for disassembling the drilling and tapping tool part from the plug and drive means part. This part becomes useless as soon as the plug part is installed and can even contribute to obstructing the passage of instruments inside the pipe. In order to check the proper functioning and condition of certain pipes, such as oil or gas pipes, the interior of the pipe is inspected by means of a tool called an instrumented scraper which moves inside the pipe. The possibility of disassembling the drilling and tapping tool part from the plug and drive means part is, therefore, particularly advantageous for this type of pipe.
According to a second object, the invention relates to a process for sealing a leak in the wall of a pipe or tank in a single step, comprising the following five sub-steps:
The purposes, objects and characteristics of the invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which:
With reference to the figures and in particular to
The self-drilling and self-tapping part 16 comprises a tap 26, or self-tapping thread, and a drilling head 28 in the form of a drill. The drilling head 28 comprises at least one flute 17 adapted to evacuate the chips during drilling. The flute 17 extends over the part of the tap 26. The drilling head has a sufficient diameter so that the cylindrical hole created replaces and eliminates the opening causing the leak. This diameter is generally between 7 mm and 15 mm. The length of the drilling head is greater than the thickness of the wall to be drilled in order to evacuate as many chips as possible.
The tap 26 has a root diameter equal to the diameter of the drill head 28. The height of the thread of the tap 26 is between 10 mm and 20 mm and is preferably equal to 15 mm. The thread pitch of the tap 26 is generally between 1 mm and 2 mm and preferably equal to 1.25 mm to induce little torque force during the tapping step. On the side opposite the drilling head 28, and according to one embodiment, the tap 26 ends in a thread runout chamfer 25 sloping at an angle of about 30 degrees with a plane perpendicular to the longitudinal axis (Z-Z′). The chamfer 25 creates an annular constriction 15 with a diameter at most equal to the diameter of the drilling head, therefore also at most equal to the root diameter of the tap 26.
The annular constriction 15 extends over the plug 14, which comprises a thread 24 whose nominal diameter is equal to the nominal diameter of the tap 26, whose thread height is equal to the height of the thread of the tap and whose thread pitch is equal to the thread pitch of the tap 26. The thread 14 begins with a chamfer 35 at the start of the thread sloping at an angle of about 30 degrees with a plane perpendicular to the longitudinal axis (Z-Z′). The two chamfers 25 and 35 form an angle of about 60 degrees between them, the annular constriction 15 being located at the junction of the two chamfers, therefore between the first and the second part.
Even when the thread 24 of the plug 14 and the tap 26 are separated by the annular constriction 15, the helical shape of their respective thread is continuous with one another. More precisely, the thread 24 is an extension of the tap 26 so that the set of the two forms a single helicoid interrupted by the annular constriction 15. The end of the thread which constitutes the thread 24 of the plug 14 extends over a clearance groove 13 which comprises a thread runout chamfer 23 on which, as its name suggests, the thread 24 ends, and an upper chamfer 21. The thread runout chamfer 23 makes an angle between 30 and 50 degrees with a plane perpendicular to the longitudinal axis (Z-Z′). The upper chamfer 21 also makes an angle between 30 and 50 degrees with a plane perpendicular to the longitudinal axis (Z-Z′). The thread runout chamfer 23 makes an angle between 60 and 100 degrees with the upper chamfer 21. The two chamfers 23 and 21 delimit the clearance groove 13 in which a sealing paste, a ring, a gasket or any other sealing means can be housed. On the other hand, the upper chamfer 21 is smooth so as to be able to crush and work-harden the thread at the internal thread end produced by the tap 26 so as to deform it. Thus, the crushed material of the thread at the internal thread end tends to move into the root of the thread and achieves a tight junction when the plug 14 is installed in the cylindrical hole created by the tap 26. The crushing and material displacement effect is also achieved in the direction of the walls of the cylindrical hole due to the angle of the chamfer. Consequently, the device comprises a chamfer deforming the thread at the internal thread end produced by the tap 26 when the device is installed. The drive means 12 serves to cooperate with a tool to rotate the device according to the invention around its longitudinal axis (Z-Z′). The drive means 12 may be a hexagonal cross-sectional shank or a hexagonal-shaped recess of the hexagon socket type. Any other type of drive means can be used without departing from the scope of the invention.
According to a second embodiment illustrated in
A variant of the first and second embodiments of the device according to the invention is illustrated in
According to
According to
The recess 152 also comprises on one of its faces a spherical hollow 154 corresponding to the diameter of the ball 155 and intended to partially house the ball in order to block the square part 153 in the recess 152 in a reversible manner. The ball 155 and the spherical hollow 154 form part of the means for assembling and disassembling the two parts of the sealing device. The device according to the invention can thus be manipulated without the two parts disassembling unintentionally. The first part 116 is disassembled from the second part 111 by a pulling force in the direction (Z-Z′) or by a pushing force in a direction perpendicular to the axis (Z-Z′) sufficient to allow the ball 155 to come out of its housing 154. This pushing force can be obtained by the passage of the instrumented scraper which, upon reaching the sealing device, exerts sufficient pressure on it to disassemble the drilling and tapping tool part 116.
On the other hand, the sealing device 100 comprises an internal thread 158 located in the first part 116 and a through internal thread 156 located in the second part 111. The two internal threads, being aligned and centered on the longitudinal axis (Z-Z′), have a diameter and threads of identical characteristics. The device also comprises a threaded rod 157 adapted to the internal threads 156 and 158 and screwed inside. The threaded rod passes through the drive means 12 and the plug 14 to the self-drilling and self-tapping part 16 which it holds tight against the plug 14.
The first part 116 is disassembled from the second part 111 by unscrewing the threaded rod 157 accessible in the middle of the drive means 12. By unscrewing the threaded rod 157, it gradually comes out of the internal thread 158. The second part 116 then falls by gravity or else, as for the embodiment described according to
The present invention also relates to a method for sealing a leak in a pipe or a tank in a single operation or step, the various sub-steps of which are illustrated in
The upper chamfer 21 being smooth, it crushes and works hardens the thread 51 at internal thread end so as to deform it. The crushed material of the thread tends to move into the root of the thread and achieves a tight junction when the plug 14 is installed in the hole 52. The crushing and material displacement effect is also achieved in the direction of the walls of the cylindrical hole thanks to the angle of the chamfer comprised between 30 and 50 degrees with respect to a plane perpendicular to the longitudinal axis (Z-Z′).
The method for sealing a leak 60 on a wall 50 of a pipe or tank produced in a single step comprises the following sub-steps:
Prior to these sub-steps, the release groove 13 can be filled with a sealing paste or else with a gasket or a sealing ring or with any other means. Once the sealing device 10 or 100 is installed, the sealing paste or any other means is trapped between the internal thread 54 and the release groove 13 of the sealing device 10 or 100.
Once the sealing device 10 or 100 is installed, the threads of the thread 24 of the plug 14 and those of the internal thread 54 are in close contact against each other and also provide a seal. However, the last sub-step is important to guarantee a perfect seal. When the end thread 51 of the internal thread 54 is crushed, it undergoes a plastic deformation which is the result of work hardening under the pressure exerted by the metal of the upper chamfer 21. The deformed metal which has become harder and inelastic makes it possible to make the plug 14 perfectly sealed. After this step, the upper chamfer 21 has fully penetrated the cylindrical hole 52.
The tap must have finished tapping the hole before the threads of the plug begins to engage the internal thread 54 of the hole 52 to avoid shifting of the threads which could interfere with the installation of the plug. Actually, when the tap has finished tapping, all the chips and wall residues removed and accumulated have been evacuated, which is essential to prevent the thread 24 of the plug from engaging in the internal thread 54 with shifting. Therefore the length of the tap 26 must be at least equal to the thickness of the wall 50. The length of the plug is also at least equal to the thickness of the wall. Preferably the plug and the tap have the same length. The length of the plug 14 is understood as being the length of the thread 24 to which is added the length of the cylindrical part 22 of the clearance groove 13, with the height of the chamfers 21 and 23 being included. The dimensions of the sealing device 10 or 100 are adapted for each wall thickness 50.
According to a second sealing method, the sealing device 10 according to the invention is associated and centered on a plate 40 which matches the curvature of the wall 50 of the pipe or tank as can be seen illustrated in
The plate 40 makes it possible to reinforce the wall 50 when the latter is altered around the opening 60 causing the leak. The diameter of the orifice 44, preferably provided in the center of the plate 40, is greater than the largest diameter of the sealing device so as to form a passage for the sealing device large enough so that the operator is not hampered by the plate during the installation of the sealing device in the orifice 44. The materials that make up the sealing device and the plate 40 can be steel, metal or plastic composite.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007060 | Jul 2020 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/068339 | 7/2/2021 | WO |
