A pig for long-distance natural gas pipelines

Abstract

The application discloses a pig for long-distance natural gas pipeline, and relates to the technical field of pipeline maintenance, which comprises a high-density alloy steel support frame, and a cleaning mechanism, wherein a permanent magnet is directly embedded in the root of a steel wire brush to form an axial gradient magnetic field penetrating the whole brush bundle, so that the steel wire is magnetized. During work, the high weight ensures that the super-thick steel brush is attached to the pipe wall with constant pressure and wide surface, the gradient magnetic field directly reaches the magnetic flux to the brush tip, strongly adsorbs and peels off the hardened black powder, and at the same time, the magnetic well is formed in the inside of the brush bundle to lock the dust. The permanent magnet is directly embedded in the root of the steel wire brush, so that the air gap and the non-magnetic isolation layer between the steel wire brush and the magnetization unit are eliminated, the magnetic flux is losslessly penetrated to the brush tip along the axial direction of the steel wire, the whole steel wire forms a strong magnet, not only has a strong magnetic adsorption force on the fine black powder on the pipe wall, but also firmly locks the separated black powder in the gap between the brush bundles to prevent secondary dust raising and downstream pollution; and a powder collecting chamber is arranged to increase the black powder collecting capacity.

Description

Technical Field

[0001] This invention relates to the field of natural gas pipeline maintenance technology, and in particular to a pipeline pig for long-distance natural gas pipelines. Background Technology

[0002] As a vital artery for energy transportation, long-distance natural gas pipelines inevitably accumulate a black solid pollutant on their inner walls during years of operation. This pollutant, commonly known in the industry as "black powder," is a mixture of corrosion products, silt, and impurities. The main component of black powder is strongly magnetic iron oxide (Fe3O4), mixed with compounds such as ferrous sulfide and ferrous carbonate. Due to its extremely fine particles (reaching micrometer or even nanometer scale), loose texture, and tendency to clump, coupled with its strong magnetism and high adhesion, black powder poses a significant challenge to the safe and efficient operation of pipelines.

[0003] Specifically, the hazards of black powder are mainly manifested in the following aspects: First, black powder suspended in the airflow will be carried by the fluid at high speed to erode compressors, valves, and metering instruments, causing severe mechanical wear, sealing failure, and even blockage, leading to unplanned shutdowns; Second, black powder easily accumulates in low-lying areas, bends, and diameter changes in pipelines, forming dense "black powder blockages," significantly reducing the flow cross-sectional area, lowering gas transmission efficiency, and in extreme cases, even causing flow interruption; Third, the black powder layer adhering to the pipe wall can easily induce the oxygen concentration cell effect, exacerbating local pitting corrosion at the bottom of the pipeline and seriously threatening the integrity of the pipeline; In addition, the presence of black powder can also interfere with the detection accuracy of precision instruments such as ultrasonic flow meters, leading to trade disputes. Therefore, effectively removing black powder, which has strong magnetic properties, fine particles, and a tendency to caking, is a core pain point in the operation and maintenance of long-distance natural gas pipelines.

[0004] Currently, the industry typically uses magnetic steel brush pigs for pipeline cleaning. However, existing conventional pigs have significant limitations when faced with the aforementioned special black powder conditions: Firstly, conventional pigs are relatively lightweight and are easily affected by turbulence in large-diameter, high-flow-rate pipeline environments, resulting in axial rolling or radial swaying. This leads to uneven contact between the steel brush and the pipe wall, or even momentary detachment, making it impossible to continuously and effectively scrape off the highly adhesive black powder. Secondly, the magnetic circuit design of traditional pigs is unreasonable. The magnetic blocks are usually fixed to the frame and there is an air gap between them and the steel brush. According to Ohm's law for magnetic circuits, the magnetic field strength decreases exponentially with distance, resulting in strong magnetism at the base of the steel brush and weak magnetism at the tip, which cannot effectively adsorb the fine particles attached to the pipe wall.

[0005] In addition, existing steel brushes are usually thin and only have "line contact" or small-area contact with the pipe wall, resulting in limited scraping force. For the hardened black powder layer formed by long-term deposition, they lack sufficient inertial impact force and stable downward pressure, making it impossible to break and peel it off. Summary of the Invention

[0006] The purpose of this invention is to provide a pipeline cleaning tool for long-distance natural gas pipelines to solve the problems existing in the prior art and improve the removal efficiency of black powder in long-distance natural gas pipelines.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides a pipeline pig for long-distance natural gas pipelines, comprising: The support frame is cylindrical; At least one cleaning mechanism; each cleaning mechanism includes a first flange, a disc cup, a gasket, a first straight cup, a wire brush, a second straight cup, and a second flange, which are sequentially arranged along the axial direction of the support frame and respectively sleeved on the support frame. The second flange is integrally formed with the support frame. The cleaning mechanism also includes at least two bolts, each bolt passing sequentially through the first flange, the disc cup, the gasket, the first straight cup, the wire brush, the second straight cup, and the second flange. The head of the bolt and the nut on the bolt clamp the first flange, the disc cup, the gasket, the first straight cup, the wire brush, the second straight cup, and the second flange. The cleaning mechanism also includes a magnetization unit, which includes a plurality of permanent magnets at the roots of the wire brush.

[0008] Preferably, part of the cleaning mechanism further includes a guide plate sandwiched between the first flange and the disc cup, the guide plate being annular and sleeved on the support frame, and the bolt passing through the guide plate.

[0009] Preferably, a counterweight is fixed on the support frame.

[0010] Preferably, the density of the support frame is greater than or equal to 7.9 g / cm³. 3 .

[0011] Preferably, the thickness of each wire brush along the axial direction of the support frame is 150mm to 180mm.

[0012] Preferably, there are two cleaning mechanisms; and the two cleaning mechanisms are spaced apart along the axial direction of the support frame; a powder collection chamber is provided inside the support frame, and an air inlet communicating with the powder collection chamber is provided on the support frame; a plurality of magnetic adsorption plates are fixed inside the powder collection chamber.

[0013] Preferably, the wire brush is made of high-carbon alloy spring steel or magnetic alloy steel; the support frame is made of alloy steel or solid steel bar.

[0014] Preferably, the magnetization unit in the cleaning mechanism forms a gradient magnetic field that runs through the entire wire brush in the same cleaning mechanism.

[0015] Preferably, the permanent magnet is an N52 neodymium iron boron magnet.

[0016] Preferably, the axial direction of the bolt is parallel to the axial direction of the support frame.

[0017] The present invention achieves the following technical effects compared to the prior art: The pipeline cleaning device for long-distance natural gas pipelines of the present invention embeds the permanent magnet in the magnetization unit directly into the root of the wire brush, eliminating the air gap and non-magnetic isolation layer between the wire brush and the magnetization unit. This allows the magnetic flux to pass through the wire axial direction to the brush tip without loss, and the entire bundle of wires forms a strong magnet. This not only generates a strong magnetic attraction force on the fine black powder on the pipe wall, but also firmly locks the scraped free black powder in the gap between the brush bundles, preventing secondary dust and downstream pollution. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the pipeline pig for long-distance natural gas pipelines according to the present invention; Figure 2 This is a side view of the pipeline pig for long-distance natural gas pipelines according to the present invention; Figure 3 This is a schematic diagram of the structure of the first flange in this invention; Figure 4 This is a schematic diagram of the support frame in this invention; Figure 5 This is a schematic diagram of the guide plate structure in this invention; Figure 6 This is a schematic diagram of the structure of the dish-shaped bowl in this invention; Figure 7 This is a schematic diagram of the structure of the spacer in this invention; Figure 8 This is a schematic diagram of the structure of the first straight bowl in this invention; Figure 9 This is a schematic diagram of the steel wire brush in this invention; In the diagram: 1. First flange; 2. Guide plate; 3. Disc cup; 4. Spacer; 5. First straight cup; 6. Wire brush; 7. Bolt; 8. Support frame; 9. Permanent magnet; 10. Second straight cup; 11. Second flange; 12. Powder collection chamber; 13. Adsorption plate; 14. Air inlet. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a pipeline cleaning tool for long-distance natural gas pipelines to solve the problems existing in the prior art and improve the removal efficiency of black powder in long-distance natural gas pipelines.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 9 As shown, this embodiment provides a pipeline pigging tool for long-distance natural gas pipelines, comprising: Support frame 8, support frame 8 is cylindrical; At least one cleaning mechanism; each cleaning mechanism includes a first flange 1, a disc cup 3, a gasket 4, a first straight cup 5, a wire brush 6, a second straight cup 10, and a second flange 11, which are sequentially arranged along the axial direction of the support frame 8 and respectively fitted onto the support frame 8. The second flange 11 is integrally formed with the support frame 8. The cleaning mechanism also includes at least two bolts 7, each bolt 7 passing sequentially through the first flange 1, the disc cup 3, the gasket 4, the first straight cup 5, the wire brush 6, the second straight cup 10, and the second flange 11. The head of the bolt 7 and the nut on the bolt 7 clamp the first flange 1, the disc cup 3, the gasket 4, the first straight cup 5, the wire brush 6, the second straight cup 10, and the second flange 11. The cleaning mechanism also includes a magnetization unit, which includes permanent magnets 9 at the roots of several wire brushes 6.

[0024] In this embodiment, the first flange 1, the second flange 11, and the bolts 7 are used together to form an axial clamping assembly structure, which integrates the disc cup 3, the straight cup, the guide plate 2, and the wire brush 6 into an independent cleaning mechanism. This not only ensures that the sealing and cleaning components are subjected to uniform force and prevents local loosening, but also facilitates the replacement and maintenance of individual components. The cooperation between the guide plate 2 and the cup further enhances the pig's ability to pass through diameter changes or bends.

[0025] In this embodiment, there are two cleaning mechanisms; however, in actual production applications, the number of cleaning mechanisms can be adjusted adaptively according to actual needs.

[0026] In the optional embodiments of this example, a preferred embodiment includes a guide plate 2 sandwiched between the first flange 1 and the disc cup 3. The guide plate 2 is annular and sleeved on the support frame 8, and the bolt 7 passes through the guide plate 2.

[0027] In the optional solutions of this embodiment, a counterweight is preferably fixed on the support frame 8.

[0028] In the optional embodiments of this example, it is more preferred that the density of the support frame 8 is greater than or equal to 7.9 g / cm³. 3 By installing a high-density alloy steel support frame 8 and incorporating internal counterweights, the total weight of the pipeline pig is 2-3 times that of a conventional pipeline pig of the same specifications. In large-diameter, high-flow-velocity (≥10m / s) natural gas pipelines, the enormous rotational inertia and axial inertia effectively suppress radial sway and axial roll caused by turbulence. The pipeline pig can maintain stable operation coaxial with the pipeline like a "piston," fundamentally eliminating the possibility of steel brush suspension or excessive local wear caused by attitude instability, ensuring the continuity and uniformity of the cleaning process.

[0029] In the optional embodiments of this example, a preferred option is that the thickness of each wire brush 6 along the axial direction of the support frame 8 is 150mm to 180mm. Increasing the axial thickness of the wire brush 6 to 150mm to 180mm (approximately three times that of a regular wire brush) creates a "wide-area contact" rather than the traditional "line contact," significantly increasing the coverage of the pipe wall and the scraping torque. Combined with the stable downward pressure from the high counterweight, this structure can easily break up the hardened black powder layer formed by long-term deposition; simultaneously, the thickened brush bundle provides a large dust-holding cavity, significantly extending the mileage of a single operation and reducing the number of times the ball needs to be passed through.

[0030] In the optional scheme of this embodiment, it is more preferred that there are two cleaning mechanisms; and the two cleaning mechanisms are arranged at intervals along the axial direction of the support frame 8; a powder collection chamber 12 is provided inside the support frame, and an air inlet 14 communicating with the powder collection chamber 12 is provided on the support frame 8; a plurality of magnetic adsorption plates 13 are fixed inside the powder collection chamber 12; in practical applications, the number of adsorption plates 13 in the collection chamber and the aperture of the air inlet 14 can be adjusted adaptively according to actual needs. A powder collection chamber 12 is provided inside the support frame, and magnetic adsorption plates 13 are fixed inside the chamber; the adsorption plates 13 themselves are made of magnetic materials or contain magnetic materials. When the brush bundle reaches saturation or encounters extra-large black powder clumps, excess impurities can be introduced into the powder collection chamber 12 through the air inlet 14 and adsorbed by the magnetic adsorption plates 13, avoiding the decrease in cleaning efficiency caused by brush bundle overload, and realizing the integrated processing of "scraping, suction, and storage".

[0031] In the optional embodiments of this example, it is more preferred that the wire brush 6 is made of high-carbon alloy spring steel or magnetic alloy steel; and the support frame 8 is made of alloy steel or solid steel bar.

[0032] In the optional embodiments of this example, a preferred embodiment is that the magnetization unit in the cleaning mechanism forms a gradient magnetic field that runs through the entire wire brush 6 in the same cleaning mechanism. The magnetic flux is forcibly delivered to the brush tip through the root-drive magnetic circuit, causing the brush tip of the wire brush 6 to maintain strong adhesion, and forming a magnetic trapping potential well that increases towards the root inside the brush bundle. This simultaneously achieves: stronger removal of black powder from the tube wall → entry into the brush gap → being locked in and not escaping, ultimately achieving a more stable and thorough cleaning effect under high-speed airflow conditions.

[0033] In the optional schemes of this embodiment, it is more preferred that the permanent magnet 9 is an N52 neodymium iron boron magnet.

[0034] In the optional embodiments of this example, it is more preferred that the axial direction of the bolt 7 is parallel to the axial direction of the support frame 8.

[0035] The specific working principle of the pipeline pig for long-distance natural gas pipelines in this embodiment is as follows: (1) When the pig is placed in a high-flow-rate natural gas pipeline, the high counterweight mechanism plays a crucial role. Because the support frame 8 is made of high-density alloy steel or solid steel bars and has built-in counterweights, the overall density of the pig is greatly increased, and the total weight is 2 to 3 times that of conventional pigs of the same specifications. According to Newton's first law, the huge mass gives the pig extremely high rotational inertia. When encountering turbulence or centrifugal force at bends in the pipeline, this inertia can effectively resist external disturbance torque and suppress the axial roll and radial sway of the pig. At the same time, the guide plate 2 and the disc cup 3 in the cleaning mechanism further constrain the pig to make a "piston-like" linear motion along the pipeline axis. This absolutely stable operating posture is the physical premise of the entire cleaning operation, ensuring that all subsequent forces can act vertically and uniformly on the pipe wall.

[0036] (2) During the smooth movement of the pig, the magnetization unit begins to work. Unlike the attenuation magnetic circuit of the traditional external magnetic block, the permanent magnet 9 (preferably N52 neodymium iron boron) in this embodiment is directly embedded in the root base of the wire brush 6. At this time, the magnetization direction is arranged along the axial direction of the wire brush 6, and the magnetic flux is no longer dissipated through the air gap, but is directly injected into the wire brush 6 made of high carbon alloy spring steel. Since the steel wire itself is an excellent magnetic conductor, the magnetic field penetrates to the brush tip along the axial direction of the brush wire, forming a gradient magnetic field that penetrates the entire wire brush 6 in a single cleaning mechanism. The magnetic field is strongest at the root of the brush and maintains an effective field strength along the brush body to the brush tip; so that the magnetic flux can penetrate to the brush tip without loss along the axial direction of the steel wire, and the entire bundle of steel wire forms a strong magnet, which not only generates a strong magnetic attraction force on the fine black powder on the pipe wall, but also firmly locks the scraped free black powder in the gap of the wire brush 6, preventing secondary dust and downstream pollution.

[0037] (3) The reinforced ultra-thick steel wire brush 6 can adhere tightly to the pipe wall with constant radial pressure. The strong magnetic field magnetizes the magnetic black powder on the pipe wall and subject it to upward attraction, weakening the adhesion between the black powder layer and the pipe wall. Then, the high hardness and high rigidity of the ultra-thick brush bundle of the steel wire brush 6 scrapes the weakened caking black powder layer over a wide area. Due to the extreme thickness of the brush bundle, its contact with the pipe wall changes from the traditional "line contact" to "band contact", ensuring that at least one row of brush bristles is in an effective cutting position even when the ellipticity of the pipe changes.

[0038] (4) The black powder particles scraped off have strong magnetism. When they leave the tube wall and enter the gap between the brush bundles, the gradient magnetic field generates a key "magnetic trap effect" - that is, the magnetic field is stronger the closer to the brush root. This forces the black powder particles to be firmly adsorbed deep in the brush bundle, which greatly improves the carrying capacity of the steel brush for black powder and prevents free black powder from passing through the cleaning device. When the dust holding capacity in the brush bundle of the steel wire brush 6 tends to be saturated, the adsorption plate 13 in the dust collection chamber 12 further plays a role in magnetizing and locking the excess black powder clumps in the chamber.

[0039] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A pipeline pigging device for long-distance natural gas pipelines, characterized in that, include: The support frame is cylindrical; At least one cleaning mechanism; each cleaning mechanism includes a first flange, a disc cup, a gasket, a first straight cup, a wire brush, a second straight cup, and a second flange, which are sequentially arranged along the axial direction of the support frame and respectively sleeved on the support frame. The second flange is integrally formed with the support frame. The cleaning mechanism also includes at least two bolts, each bolt passing sequentially through the first flange, the disc cup, the gasket, the first straight cup, the wire brush, the second straight cup, and the second flange. The head of the bolt and the nut on the bolt clamp the first flange, the disc cup, the gasket, the first straight cup, the wire brush, the second straight cup, and the second flange. The cleaning mechanism also includes a magnetization unit, which includes a plurality of permanent magnets at the roots of the wire brush.

2. The pipeline pigging device for long-distance natural gas pipelines according to claim 1, characterized in that: The cleaning mechanism also includes a guide plate sandwiched between the first flange and the disc cup, the guide plate being annular and fitted onto the support frame, and the bolt passing through the guide plate.

3. The pipeline pig for long-distance natural gas pipelines according to claim 1, characterized in that: A counterweight is fixed on the support frame.

4. The pipeline pigging device for long-distance natural gas pipelines according to claim 1, characterized in that: The density of the support frame is greater than or equal to 7.9 g / cm³. 3 .

5. The pipeline pigging device for long-distance natural gas pipelines according to claim 1, characterized in that: The thickness of each wire brush along the axial direction of the support frame is 150mm to 180mm.

6. The pipeline pig for long-distance natural gas pipelines according to claim 1, characterized in that: The number of cleaning mechanisms is two; and the two cleaning mechanisms are spaced apart along the axial direction of the support frame; a powder collection chamber is provided inside the support frame, and an air inlet communicating with the powder collection chamber is provided on the support frame; a number of magnetic adsorption plates are fixed inside the powder collection chamber.

7. The pipeline pigging device for long-distance natural gas pipelines according to claim 1, characterized in that: The wire brush is made of high-carbon alloy spring steel or magnetic alloy steel; the support frame is made of alloy steel or solid steel bar.

8. The pipeline pig for long-distance natural gas pipelines according to claim 1, characterized in that: The magnetization unit in the cleaning mechanism forms a gradient magnetic field that runs through the entire wire brush in the same cleaning mechanism.

9. The pipeline pig for long-distance natural gas pipelines according to claim 1, characterized in that: The permanent magnet is an N52 neodymium iron boron magnet.

10. The pipeline pig for long-distance natural gas pipelines according to claim 1, characterized in that: The axial direction of the bolt is parallel to the axial direction of the support frame.

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