A combined pig for a pipe wall opening section and a pigging method thereof

Abstract

The application provides a combined pig for a pipe wall opening section and a pigging method thereof, which comprises a head unit, a tail unit and at least one intermediate unit; the head unit and the tail unit are provided with a guide contour in sealing cooperation with the inner wall of the pipeline, are made of an elastomer material, and are internally provided with a positioning device; the intermediate unit is provided with an axial limiting structure, and is internally provided with a flexible connecting piece. By arranging the combined structure of the head unit, the intermediate unit and the tail unit in series connection, and by arranging the total length of the pig to be greater than the effective axial length of the pipe wall opening section, at least one end can be maintained in the sealed pipe section during the whole process of passing through the opening section, the pressure release window period is eliminated, the driving pressure difference before and after the pig is stably maintained, the pigging operation failure problem of the pipe wall opening section is greatly improved, the continuous pigging operation is ensured, and the pipeline shutdown and operation and maintenance risks are reduced.

Description

Technical Field

[0001] This invention relates to the field of pipeline cleaning technology, specifically to a combined pipeline cleaning tool and its cleaning method for pipe wall opening sections. Background Technology

[0002] In various industrial pipeline systems, there are widely existing pipe wall openings with fluid communication openings, such as tubular filters, drainage pipes, spray pipes, and perforated pipes for silencers. During operation, these pipe wall openings are prone to accumulating substances, leading to a reduction in the flow cross-section and a decrease in functional efficiency. Regular online cleaning with a pipeline pig is required. Existing pipeline pigs mainly include two types: integral and segmented. Integral pigs have a simple structure but cannot pass through bends with small bending radii. Segmented pigs consist of multiple units connected in series, and the units can be relatively deflected, which can adapt to a certain degree of pipe bending.

[0003] Existing segmented pipeline pig optimization designs mostly focus on the ability to pass through bends, generally failing to consider the matching relationship between the length of the pig and the axial length of the pipe wall opening section. There has long been a corresponding technical bias in this field, generally believing that the total length of the pig should be controlled within the range of 1.3 to 2.0 times the inner diameter of the pipe. The reason is that an excessive length will not only increase the difficulty of installing the pig into the upstream straight pipe section, but also significantly increase the travel resistance of the pig at bends.

[0004] However, in practical applications, for pipe wall openings with sealed cavities on the outside, pigs designed according to the above-mentioned technical bias are prone to jamming and failure: when the pig fully enters the pipe wall opening section, its head and tail simultaneously detach from the sealed pipe sections at both ends of the opening section, and the driving fluid can flow directly into the outer sealed cavity through the pipe wall opening, causing the driving pressure difference before and after the pig to disappear instantly, the pig loses its forward momentum and stops, directly causing the pigging operation to be interrupted, which greatly increases the pipeline operation and maintenance costs and the risk of pipeline shutdown. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a combined pig for pipe wall perforation sections and a corresponding pigging method to solve the problems mentioned in the background section. The invention features a novel structure, employing a combined structure with a head unit, a middle unit, and a tail unit connected in series. Furthermore, the total length of the pig is greater than the effective axial length of the pipe wall perforation section. When traversing the perforation section, at least one end can remain within a sealed section, eliminating the pressure release window, stabilizing the driving pressure differential, improving pigging jamming issues, ensuring continuous operation, and reducing pipeline outage and maintenance risks.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a combined pipe cleaning device and a pipe cleaning method for pipe wall perforation sections, comprising:

[0007] One head unit;

[0008] A tail unit;

[0009] and at least one intermediate unit;

[0010] Both the head unit and the tail unit have a guide profile that seals against the inner wall of the pipe, are made of elastomeric material, and have a positioning device inside.

[0011] The intermediate unit has an axial limiting structure and a flexible connector inside, which allows relative deflection between adjacent units; and the intermediate unit does not have a positioning device inside.

[0012] The head unit, the tail unit, and the middle unit are connected in series in sequence by rigid connectors, and a sealing element is provided between adjacent units;

[0013] The total length of the combined pig is greater than the effective axial length of the pipe wall opening section to which it is applied.

[0014] Furthermore, the flexible connector is a hinge structure, a universal joint structure, or an elastomer connection structure.

[0015] Furthermore, the positioning device is a magnetic element, radio frequency tag, or radioactive tracer that can be used by an external detector to detect the location.

[0016] Furthermore, the sealing element is a replaceable annular sealing ring that is independently installed at the connection between adjacent units, and the outer diameter of the sealing element is larger than the outer diameter of the head unit, the tail unit, and the intermediate unit.

[0017] Furthermore, there are multiple intermediate units, which are connected in series in sequence by rigid connectors. Each intermediate unit has a flexible connector inside, and a sealing element is provided at the connection between two adjacent intermediate units.

[0018] Furthermore, the rigid connector is a threaded connector, a snap-fit ​​connector, or a welded fixing sleeve.

[0019] Furthermore, the outer surfaces of the head unit, the tail unit, and the intermediate unit form a sealed contact with the inner wall of the pipe, and the sealing element forms an interference contact with the inner wall of the pipe.

[0020] Furthermore, the intermediate unit includes a rigid frame and an elastomeric layer covering the outside of the rigid frame.

[0021] Furthermore, the periphery of the pipe wall opening section has a sealed cavity, which is used to collect substances seeping from the pipe wall opening and to provide back pressure during the cleaning process.

[0022] A method for cleaning pipes using a combined pipe cleaning tool with an opening in the pipe wall, characterized by comprising the following steps:

[0023] S1: Assembly and Deployment: The head unit, at least one intermediate unit, and the tail unit are sequentially coaxially spliced ​​and fixed with rigid connectors, so that the total length of the combined pig is greater than the effective axial length of the pipe wall opening section to which it is applied. After assembly, the pig is sent from the pipeline deployment end into the smooth sealing section upstream of the pipe wall opening section, and the tail unit is located in the upstream sealing section.

[0024] S2: Drive movement: Drive fluid is introduced into the pipeline, and the entire pig moves forward along the pipeline axis through the pressure of the tail unit. The sealing guide contour of the head unit guides the direction of movement, and the sealing elements at each connection form an interference contact with the inner wall of the pipeline to prevent the drive fluid from leaking ahead.

[0025] S3: Flexible deflection in bends: When the pig travels to the bend, the flexible connectors inside each intermediate unit deflect in sequence, allowing the pig to pass through the bend in a flexible manner, while each sealing element maintains interference contact with the inner wall of the pipe.

[0026] S4: Opening Section Pressure Relief Crossing: When the pig travels to the pipe wall opening section with a sealed cavity on the periphery, since the total length of the pig is greater than the effective axial length of the pipe wall opening section, the head unit and the tail unit do not simultaneously detach from the smooth sealing sections at both ends of the pipe wall opening section during the entire crossing process, eliminating the pressure relief window period of the driving fluid. At the same time, the sealed cavity maintains a stable back pressure, so that a continuous pressure difference is formed between the driving pressure and the back pressure, pushing the pig to completely cross the pipe wall opening section;

[0027] S5: Scraping and cleaning: The pig moves forward under continuous thrust, and the sealing elements at each connection successively scrape off the material accumulated at the pipe opening and the inner surface of the pipe, and push the scraped material to the downstream drain or collection device.

[0028] S6: Position tracking and retrieval: The external position detector tracks the position of the pig in real time by receiving signals from the positioning devices inside the head and tail units. The intermediate unit has no positioning device to eliminate signal interference. When the external detector confirms that the tail unit has passed the outlet of the pipe wall opening section, it stops supplying the driving fluid or introduces the reverse driving fluid to make the pig return to the initial position and be taken out of the pipeline.

[0029] The beneficial effects of this invention are:

[0030] 1. This invention, by setting up a combined structure of head unit, middle unit and tail unit connected in series, and with the total length of the pig being greater than the effective axial length of the pipe wall opening section, can maintain at least one end in the sealed pipe section throughout the entire process of crossing the opening section, eliminate the pressure release window period, stably maintain the driving pressure difference before and after the pig, greatly improve the problem of jamming failure in the pipe wall opening section pigging operation, ensure the continuous operation of pigging operation, and reduce the risk of pipeline shutdown and maintenance.

[0031] 2. By setting up a flexible connector and axial limiting structure built into the intermediate unit, the present invention allows adjacent units to deflect relative to each other, improves the adaptability of the pig to curved pipe sections, ensures the smooth passage of small-radius bends, and strengthens the axial positioning effect of adjacent units, reducing the risk of loosening during travel.

[0032] 3. By setting independent replaceable sealing elements at the connection between adjacent units, and forming a multi-seal structure with the outer wall of each unit, the sealing performance of the driving fluid can be improved, the premature leakage of fluid can be reduced, and the cleaning effect of pipe wall deposits can be enhanced. After wear, the sealing elements can be replaced individually, effectively reducing the later maintenance cost of the equipment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall cross-sectional structure of a combined pipe cleaning device for pipe wall perforation sections according to the present invention.

[0034] Figure 2 This is a partial cross-sectional structural diagram of a combined pipe cleaning device for pipe wall perforation sections according to the present invention.

[0035] Figure 3 This invention relates to a combined pipe cleaning device for pipe wall perforation sections. Figure 3 A magnified schematic diagram of the central part of the structure;

[0036] Figure 4 This is a schematic diagram of the cross-sectional structure of a combined pipe cleaning device for pipe wall opening sections according to the present invention.

[0037] Figure 5 This is a schematic flowchart of a combined pipe cleaning method for pipe wall perforation sections according to the present invention.

[0038] In the figure: 100, head unit; 200, tail unit; 300, intermediate unit; 310, axial limiting structure; 320, flexible connector; 330, rigid frame; 340, elastomer layer; 400, rigid connector; 500, sealing element; 600, sealing cavity; 700, positioning device. Detailed Implementation

[0039] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0040] Please refer to Figures 1 to 4 This invention provides a technical solution: a combined pipe cleaning tool and a pipe cleaning method for pipe wall perforation sections, comprising:

[0041] A head unit 100 has a guide profile that seals against the inner wall of the pipeline. It is made of an elastomeric material and is used to guide the direction of travel of the pig and reduce travel resistance. An internal positioning device 700 is provided for external detectors to track the head position in real time.

[0042] A tail unit 200 has a guide profile that seals against the inner wall of the pipeline. It is made of an elastomeric material and is used to withstand the pressure of the driving fluid to propel the pig forward. An internal positioning device 700 is installed so that an external detector can track the tail position in real time. By setting positioning devices at both ends, accurate position monitoring can be achieved while avoiding interference between multiple signal sources.

[0043] And at least one intermediate unit 300, having an axial limiting structure 310 for axial positioning with adjacent units to prevent loosening of the connection, and having a flexible connector 320 inside to allow relative deflection of adjacent units to enable small bending radius pipes to pass through, and the intermediate unit 300 does not have a positioning device inside to avoid signal interference and ensure positioning accuracy.

[0044] The head unit 100, tail unit 200 and middle unit 300 are connected in series in sequence by rigid connector 400. A sealing element 500 is provided between adjacent units. The sealing element 500 is in interference contact with the inner wall of the pipe to form a multi-seal to prevent the driving fluid from leaking ahead, and at the same time scrapes off the material accumulated in the pipe opening and the inner wall of the pipe.

[0045] The total length of the combined pig is greater than the effective axial length of the pipe wall opening section to which it is applied, ensuring that the head unit 100 and the tail unit 200 do not simultaneously detach from the smooth sealing sections at both ends during the entire process of traversing the opening section, eliminating the pressure release window period, maintaining the driving pressure differential, and solving the problem of pig jamming.

[0046] In this embodiment, the flexible connector 320 is a hinge structure, a universal joint structure, or an elastomer connection structure, which can be flexibly selected according to the bending route of the pipeline.

[0047] The positioning device 700 is a magnetic element, radio frequency tag, or radioactive tracer that can be used by external detectors to detect the position, adapting to the position tracking needs under different working conditions.

[0048] The sealing element 500 is a replaceable annular sealing ring that is independently installed at the connection between adjacent units. It can be replaced individually after wear, reducing maintenance costs. The outer diameter of the sealing element 500 is larger than the outer diameter of the head unit 100, the tail unit 200 and the middle unit 300, ensuring that it preferentially makes interference contact with the pipe wall to form a reliable seal. Each unit body maintains a small gap with the pipe wall to reduce travel resistance.

[0049] There are multiple intermediate units 300 connected in series via rigid connectors 400. Each intermediate unit 300 has a flexible connector 320 inside, and a sealing element 500 is provided at the connection between two adjacent intermediate units 300. The total length of the pig can be flexibly configured by adjusting the number and axial length of the intermediate units 300 to adapt to different opening sections.

[0050] The rigid connector 400 is a threaded connector, a snap-fit ​​connector, or a welded fixing sleeve.

[0051] The outer surfaces of the head unit 100, tail unit 200, and intermediate unit 300 form a sealed contact with the inner wall of the pipe, and the sealing element 500 forms an interference contact with the inner wall of the pipe. The sealing of the outer surface of the unit and the interference contact of the sealing element constitute multiple seals to ensure sealing reliability.

[0052] The intermediate unit 300 includes a rigid frame 330 and an elastomer layer 340 covering the rigid frame 330. The rigid frame 330 provides structural strength, and the elastomer layer 340 forms an elastic seal with the pipe wall and absorbs local stress during pipe bending.

[0053] The periphery of the pipe wall opening section has a sealed cavity 600 for collecting substances seeping from the pipe wall opening and providing back pressure during the pigging process. When one end of the pig is connected to the opening section, a stable back pressure is formed in the sealed cavity 600, creating a continuous pressure difference with the driving pressure to propel the pig forward, while providing a controllable release space for the leaking fluid and avoiding sudden pressure changes.

[0054] When using the device, after this combined pig is inserted into the pipeline to be cleaned, the driving fluid acts on the end face of the tail unit 200 to provide forward propulsion. Through the rigid connector 400, it drives the head unit 100 and the intermediate unit 300 connected in series to move along the pipeline axis. The elastic guide contour of the head unit 100 guides the direction of travel and reduces the travel resistance. The sealing element 500 at the connection of each adjacent unit makes interference contact with the inner wall of the pipeline. During the travel, it simultaneously scrapes away the accumulated deposits on the inner wall of the pipeline and the opening of the pipe wall. At the same time, it forms a multi-seal structure with the outer wall of each unit to prevent the driving fluid from leaking ahead and to stably maintain the driving pressure difference before and after the pig.

[0055] When the pig passes through a curved pipe section, the flexible connectors 320 built into each intermediate unit 300 allow the adjacent units to deflect relative to each other. The elastic layer 340 covering the rigid skeleton 330 of the intermediate unit 300 deforms to adapt to the curvature of the pipe. The axial limiting structure 310 ensures the reliability of the unit connection and ensures that the pig can pass through the small bending radius bend smoothly.

[0056] When the pig passes through the pipe wall opening section with the outer sealed cavity 600, since the total length of the pig is greater than the effective axial length of the opening section, at least one of the head unit 100 and the tail unit 200 is always in the smooth sealed pipe section at both ends of the opening section throughout the entire journey. This completely eliminates the pressure release window period and prevents the driving fluid from rushing into the sealed cavity 600 in large quantities through the opening. The stable back pressure formed by the sealed cavity 600 continuously maintains the driving pressure difference, solving the problem of pig stalling and jamming from the root. The positioning device 700 built into the head unit 100 and the tail unit 200 can be tracked in real time by an external detector. The design of the intermediate unit 300 without a positioning source avoids signal interference and ensures positioning accuracy.

[0057] Please refer to Figure 5 A method for cleaning pipes using a combined pipe cleaning tool with an opening in the pipe wall, comprising the following steps:

[0058] S1: Assembly and Deployment: The head unit 100, at least one intermediate unit 300 and the tail unit 200 are sequentially coaxially spliced ​​and fixed by rigid connectors 400, so that the total length of the combined pig is greater than the effective axial length of the pipe wall opening section to which it is applied. After assembly, the pig is sent from the pipeline deployment end into the smooth sealing section upstream of the pipe wall opening section, and the tail unit 200 is located in the upstream sealing section.

[0059] S2: Driving movement: Driving fluid is introduced into the pipeline, and the tail unit 200 is pressurized to drive the entire pig to move forward along the pipeline axis. The sealing guide contour of the head unit 100 guides the direction of movement. The sealing element 500 at each connection forms an interference contact with the inner wall of the pipeline to prevent premature leakage of the driving fluid.

[0060] S3: Flexible deflection of the bend: When the pig travels to the bend, the flexible connectors 320 inside each intermediate unit 300 deflect in turn, so that the pig passes through the bend in a flexible posture, while each sealing element 500 maintains interference contact with the inner wall of the pipe.

[0061] S4: Opening Section Pressure Relief Crossing: When the pig travels to the pipe wall opening section with a sealing cavity 600 on the periphery, since the total length of the pig is greater than the effective axial length of the pipe wall opening section, the head unit 100 and the tail unit 200 do not simultaneously detach from the smooth sealing sections at both ends of the pipe wall opening section during the entire crossing process, eliminating the pressure relief window period of the driving fluid. At the same time, the sealing cavity 600 maintains a stable back pressure, so that a continuous pressure difference is formed between the driving pressure and the back pressure, pushing the pig to completely cross the pipe wall opening section;

[0062] S5: Scraping and cleaning: The pig moves forward under continuous thrust, and the sealing elements 500 at each connection point scrape off the material accumulated at the pipe wall opening and the inner surface of the pipe in sequence, and push the scraped material to the downstream drain or collection device.

[0063] S6: Position tracking and retrieval: The external position detector tracks the position of the pig in real time by receiving signals from the internal positioning device 700 of the head unit 100 and the tail unit 200. The intermediate unit 300 has no positioning device to eliminate signal interference. When the external detector confirms that the tail unit 200 has passed the outlet of the pipe wall opening section, it stops supplying the driving fluid or introduces the reverse driving fluid to make the pig return to the initial position and be taken out of the pipeline.

[0064] The foregoing has shown and described the basic principles and main features of the present invention and its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0065] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A combined pipe cleaning device for pipe wall perforation sections, characterized in that, include: One head unit (100); A tail unit (200); and at least one intermediate unit (300); Both the head unit (100) and the tail unit (200) have a guide profile that seals against the inner wall of the pipe, are made of elastomeric material, and have a positioning device (700) inside. The intermediate unit (300) has an axial limiting structure (310) and a flexible connector (320) inside it. The flexible connector (320) allows relative deflection between adjacent units; and no positioning device is provided inside the intermediate unit (300). The head unit (100), the tail unit (200) and the middle unit (300) are connected in series in sequence by a rigid connector (400), and a sealing element (500) is provided between adjacent units. The total length of the combined pig is greater than the effective axial length of the pipe wall opening section to which it is applied.

2. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The flexible connector (320) is a hinge structure, a universal joint structure, or an elastomer connection structure.

3. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The positioning device (700) is a magnetic element, radio frequency tag, or radioactive tracer that can be used by an external detector to detect the location.

4. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The sealing element (500) is a replaceable annular sealing ring that is independently installed at the connection of adjacent units, and the outer diameter of the sealing element (500) is larger than the outer diameter of the head unit (100), the tail unit (200) and the middle unit (300).

5. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The number of intermediate units (300) is multiple, and the multiple intermediate units (300) are connected in series in sequence by rigid connectors (400). Each intermediate unit (300) is provided with a flexible connector (320) inside, and a sealing element (500) is provided at the connection between two adjacent intermediate units (300).

6. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The rigid connector (400) is a threaded connector, a snap connector, or a welded fixing sleeve.

7. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The outer surfaces of the head unit (100), the tail unit (200), and the intermediate unit (300) form a sealed contact with the inner wall of the pipe, and the sealing element (500) forms an interference contact with the inner wall of the pipe.

8. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The intermediate unit (300) includes a rigid frame (330) and an elastomeric layer (340) covering the outside of the rigid frame (330).

9. A combined pipe cleaning device for pipe wall perforation sections according to claim 1, characterized in that: The periphery of the pipe wall opening section has a sealing cavity (600) for collecting substances seeping from the pipe wall opening and providing back pressure during the cleaning process.

10. A method for cleaning a combined pipe cleaning device for a pipe wall perforation section according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Assembly and deployment: The head unit (100), at least one intermediate unit (300) and the tail unit (200) are sequentially coaxially spliced ​​and fixed by rigid connectors (400) so that the total length of the combined pig is greater than the effective axial length of the pipe wall opening section to which it is applied. After assembly, the pig is sent from the pipeline deployment end into the smooth sealing section upstream of the pipe wall opening section, and the tail unit (200) is located in the upstream sealing section. S2: Driving movement: Driving fluid is introduced into the pipeline, and the tail unit (200) is pressure-driven to drive the entire pig forward along the pipeline axis. The sealing guide contour of the head unit (100) guides the direction of movement, and the sealing elements (500) at each connection form an interference contact with the inner wall of the pipeline to prevent the driving fluid from leaking ahead. S3: Flexible deflection of the bend: When the pig travels to the bend, the flexible connectors (320) inside each intermediate unit (300) deflect in turn, so that the pig passes through the bend in a flexible posture, while each sealing element (500) maintains interference contact with the inner wall of the pipe. S4: Opening section anti-pressure relief crossing: When the pig travels to the pipe wall opening section with a sealed cavity (600) on the periphery, since the total length of the pig is greater than the effective axial length of the pipe wall opening section, the head unit (100) and the tail unit (200) do not simultaneously detach from the smooth sealing sections at both ends of the pipe wall opening section during the entire crossing process, eliminating the pressure relief window period of the driving fluid. At the same time, the sealed cavity (600) maintains a stable back pressure, so that a continuous pressure difference is formed between the driving pressure and the back pressure, pushing the pig to completely cross the pipe wall opening section; S5: Scraping and cleaning: The pig moves forward under continuous thrust, and the sealing elements (500) at each connection successively scrape off the material accumulated at the pipe wall opening and the inner surface of the pipe, and push the scraped material to the downstream drain or collection device. S6: Position tracking and retrieval: The external position detector tracks the position of the pig in real time by receiving signals from the internal positioning device (700) of the head unit (100) and the tail unit (200). The intermediate unit (300) has no positioning device to eliminate signal interference. When the external detector confirms that the tail unit (200) has passed through the pipe wall opening section outlet, it stops supplying the driving fluid or introduces the reverse driving fluid, so that the pig returns to the initial position and is taken out of the pipeline.

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