An oil and gas pipeline sealing head

Abstract

This invention discloses a sealing head for oil and gas pipeline operations, belonging to the technical field of oil and gas pipeline construction. The sealing head includes a main body, an end cap, an annular airbag, and an installation ring. The main body has a cylindrical structure with a positioning ring platform and a long step. An inflation tube is installed inside the main body. The end cap is installed in a threaded end hole via a threaded end. One or more annular airbags are fitted onto the long step. Compared with existing technologies, the sealing connection between the annular airbag and the internal installation ring uses a 180° rotating flange, which significantly improves its sealing performance. Compared with the traditional 90° folding edge scheme, the internal pressure of the airbag sealing can be increased by more than 60%. Furthermore, this sealing head adopts a multi-airbag coaxial series arrangement and is equipped with a safety valve, enabling it to adapt to medium and high pressures and complex environments. Even if a single airbag is damaged due to burrs or foreign objects scraping the inner wall, the other airbags can still seal independently, with a sealing pressure reaching 1.6 to 2.5 MPa.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas pipeline construction technology, and particularly relates to an oil and gas pipeline sealing head. Background Technology

[0002] In the construction of long-distance oil and gas pipelines and urban gas pipelines, pipeline beveling is either prefabricated by the manufacturer or fabricated on-site. Due to the large scale of pipeline projects and long construction periods, work is carried out on a phased basis according to construction milestones. After each day's construction, unwelded pipeline beveling (commonly known as "left ends") will remain. If not sealed, animals, dust, and sand can enter the pipeline at night, potentially damaging it or affecting subsequent pressure testing and cleaning processes. Finding suitable sealing devices due to varying pipeline diameters has long been a challenge for construction personnel in this field. Not only during the initial construction phase but also during later pipeline maintenance and inspection, technicians require sealing devices of appropriate size and high pressure resistance. For example, after completing a section of construction, it is necessary to seal and pressure test that section of the pipeline; another example is when oil and gas pipelines or valves are damaged after pressurization, sometimes temporary sealing is required under pressure for repair and replacement. How to reliably and promptly seal leaking pipelines under pressure to prevent the leakage of flammable and explosive liquids or gases has become a key technical challenge.

[0003] Currently, some technicians have proposed a technical solution using pipeline sealing airbags. Because the airbag's size is adjustable, it can meet the sealing needs of pipelines of different sizes, which is of positive significance. However, through further analysis and research, the following failure scenarios are prone to occur when existing sealing airbags operate under pressure:

[0004] 1) The external force on the airbag is greater than the frictional force, causing it to slip as a whole and resulting in airbag sealing failure. (Chen Jing, Yan Shuwang. Working mechanism and experimental verification of sealing airbags with different diameter matching degree [J]. Journal of Harbin Institute of Technology, 2018, 50(6): 131-132)

[0005] 2) The external pressure on the airbag is greater than the internal pressure, causing the airbag to become unstable and deformed, thus failing. (Zeng Qiang. Application of pipeline sealing airbags in pipeline maintenance [J]. Water Conservancy Construction and Management, 2015, 35(9): 76-77.)

[0006] In addition to the airbag failure issues mentioned above, existing airbag structures also have the following technical defects:

[0007] 1) The sealing airbags generally adopt a single airbag structure. The working conditions of the inner wall of the pipeline are complex. During the expansion and sealing process, the airbag is easily damaged if it encounters burrs or scratches on the inner wall, or if it is hit or scraped by foreign objects at the inner and outer pipe openings, it is easy to cause sealing failure.

[0008] 2) When the sealing airbag expands, its axis is easily deflected under pressure and external force, which can easily lead to asymmetry of the contact surface between the airbag and the inner wall of the pipe, uneven stress, and stress concentration points on the outer contour, resulting in a rapid decrease in the overall pressure bearing capacity.

[0009] Solving or improving the aforementioned problems faced by existing airbags is the key to further improving the quality of airbag sealing and expanding the application scope of airbags. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides an oil and gas pipeline sealing head. The sealing connection between the annular airbag and the internal mounting ring employs a 180° rotating flange, which significantly improves its sealing performance. Furthermore, this sealing head adopts a multi-airbag coaxial series arrangement and is equipped with a safety valve, making it adaptable to medium and high pressure and complex environments, and highly suitable for oil and gas pipeline sealing operations.

[0011] The present invention solves the above problems through the following technical means:

[0012] A sealing head for oil and gas pipeline operations, characterized in that it includes a main body, an end cap, an annular air bladder, and an installation ring, wherein: the main body is a cylindrical structure, one end of the main body is provided with a positioning ring platform, the main body forms a long step on the inner side of the positioning ring platform, the other end of the main body is provided with a threaded end hole, and an inflation pipe is provided inside the main body;

[0013] The inflation tube includes an axially arranged main inflation hole and radially arranged branch inflation holes. An inflation nozzle is located at the outer end of the main inflation hole, and a nozzle sealing ring is fitted onto the nozzle. The inner end of the main inflation hole is sealed, and the inner end of the branch inflation holes communicates with the main inflation hole. The end cap is installed in a threaded end hole via a threaded end. One or more annular airbags are mounted on a long step, with positioning rings and end caps limiting the two sides of the annular airbags. Spacer rings are provided between multiple annular airbags, and the inner opening of the annular airbags has a 180° angle. The annular airbag has a rotating flange and a raised sealing ring on its outer side for contacting and sealing the tube wall. The mounting ring is fitted onto a long step and located inside the annular airbag. The mounting ring is used to position and seal the annular airbag. The surface of the mounting ring has an air vent located on the inflation port. The inner wall of the mounting ring has a positioning boss in the middle. The steps on both sides of the positioning boss form a mounting cavity for mounting the annular airbag. The bottom of the mounting cavity has a limiting ring groove for mounting the rotating flange of the annular airbag.

[0014] Preferably, it also includes a safety valve, which is installed in the inflation port and includes a perforated waist-shaped nut, a vent groove, a moving shaft, a base, a sealing cone, a valve body sealing ring, a vent hole, a sealing spring, a fixed magnetic ring, and a moving magnetic ring, wherein:

[0015] The perforated waist-shaped nut is installed in the threaded cavity at the top of the inflation port, and the vent groove is formed between the waist of the perforated waist-shaped nut and the inner wall of the threaded cavity.

[0016] The movable shaft is movably installed in the central hole of the perforated waist-shaped nut;

[0017] The chassis is located at the bottom of the moving shaft, and the chassis and the inflation port are fitted with a clearance of 0.20mm to 1.50mm.

[0018] The sealing cone is located on the underside of the chassis. The size of the sealing cone is the same as the size of the bottom hole of the inflation port. A valve body sealing ring is fitted on the sealing cone.

[0019] The valve body sealing ring is tightly fitted to the chassis and has the same size. Multiple vent holes are symmetrically opened around the valve body sealing ring and the chassis.

[0020] The sealing spring is installed between the chassis and the perforated waist-shaped nut;

[0021] The fixed magnetic ring is mounted on the movable shaft and is fixedly connected to the perforated waist-shaped nut;

[0022] The moving magnetic ring is mounted on the moving shaft and is fixedly connected to the chassis;

[0023] The fixed magnetic ring and the moving magnetic ring have opposite poles that are opposite to each other and attract each other.

[0024] Preferably, it also includes positioning covers disposed at both ends of the main body, a retractable positioning rod, a drive disc for moving the positioning rod, and a drive rod for moving the drive disc, wherein:

[0025] The front positioning cover is fixed to the end face of the positioning ring platform, and the rear positioning cover is set on the top of the end cover and forms an integral structure with the end cover.

[0026] The positioning cover has a mounting hole in the center and three or four sliding grooves arranged radially symmetrically on the positioning cover. The bottom of the sliding groove on the front side of the positioning cover is provided with a connecting screw, which is used to connect the positioning cover and the main body. The front side of the positioning cover is provided with an air nozzle hole for installing an air nozzle.

[0027] The positioning rod includes a sliding plate and a transmission rod. The sliding plate is movably installed in the slide groove. The transmission rod is vertically set at the bottom of the sliding plate. A sliding sleeve is fitted on the transmission rod. A limit nut is installed on the top of the transmission rod. An elastic contact head is wrapped around the outside of the sliding plate.

[0028] The drive disk is provided with a limiting hole in the middle, and three or four drive arc grooves are symmetrically arranged on the drive disk. The drive arc grooves are fitted on the sliding sleeve and positioned by the limiting nut. The drive disk is also provided with an air nozzle arc groove for installing an air nozzle.

[0029] The drive rod passes sequentially through the limiting hole of the front drive disc, the mounting hole of the front positioning cover, the transmission hole of the main body, the center threaded hole of the end cover, the mounting hole of the rear positioning cover, and the limiting hole of the rear drive disc. The rotation of the drive rod can synchronously drive the rotation of the front drive disc and the rear drive disc, and drive the drive arc groove to rotate so as to drive the positioning rod to move back and forth synchronously along the slide groove.

[0030] Preferably, one or more balls are provided at the bottom of the groove near the outer end to reduce the moving friction of the drive positioning rod.

[0031] Preferably, the limiting hole of the drive disk is provided with a keyway, which engages with the spline on the drive rod for transmission.

[0032] Preferably, during the process of the drive disk rotating at a constant speed of 35° to 55°, the sliding sleeve also moves from the bottom end to the top end, and the envelope of the projection of the outer contour of the sliding sleeve on the drive disk forms the inner contour of the drive arc groove.

[0033] Preferably, the air nozzle arc groove is arranged concentrically with the drive disk.

[0034] Preferably, the end of the drive rod is provided with a drive head, both ends of the drive rod are provided with threaded sections, and a spring is provided between the drive head and the front drive disc.

[0035] Preferably, one or more transmission sealing rings are fitted onto the middle of the drive rod, and the transmission sealing rings are used to dynamically seal the gap between the drive rod and the transmission hole.

[0036] Preferably, the transmission sealing ring is an O-ring or a Y-ring.

[0037] The oil and gas pipeline sealing head of the present invention has the following beneficial effects:

[0038] (1) The sealing connection between the annular airbag and the internal mounting ring adopts a 180° rotating flange, which increases its contact surface and friction, and can significantly improve its sealing performance. Compared with the traditional 90° folding scheme, the internal pressure of the airbag can be increased by more than 60%, which solves the technical problem that the cross-section of the rubber airbag end face becomes narrow due to the increase of the internal pressure during the sealing process, which leads to the rubber airbag easily falling off or leaking and failing.

[0039] (2) The sealing head adopts a multi-airbag coaxial series arrangement and is equipped with a safety valve. It can adapt to medium and high pressure and complex environment. Even if a certain airbag is damaged due to inner wall burrs or foreign objects, the other airbags can still be sealed independently. The sealing pressure can reach 1.6 to 2.5 MPa.

[0040] (3) The sealing head is designed with a retractable stop device, including a positioning cover, a positioning rod, a drive disc and a drive rod. The rotation of the drive rod can drive the front and rear drive discs to rotate synchronously. The synchronous rotation of the drive discs uses the interaction between the drive arc groove and the positioning rod to drive the positioning rod to extend or retract synchronously. This structure can not only increase the friction of the airbag as a whole and effectively prevent its overall slippage, but also keep its axis stable and not deviated when the airbag is sealed and expanded, ensuring that the contact surface between the airbag and the inner wall of the pipe is symmetrical and the force is uniform, thus improving the overall pressure bearing capacity. Attached Figure Description

[0041] To more clearly illustrate the technical solution of the present invention, 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.

[0042] Figure 1 This is a schematic diagram of the dual-airbag structure of the present invention;

[0043] Figure 2 This is a schematic diagram of the inflation tube structure of the present invention;

[0044] Figure 3 This is a schematic diagram of the safety valve structure of the present invention;

[0045] Figure 4 This is a schematic diagram of the hole-shaped waist nut structure of the present invention;

[0046] Figure 5 This is a schematic diagram of the assembly of the moving shaft, chassis, and valve body sealing ring of the present invention;

[0047] Figure 6 This is a schematic diagram of the vent structure of the present invention;

[0048] Figure 7 This is a schematic diagram of the working process of the present invention;

[0049] Figure 8 This is a schematic diagram of the mounting ring structure of the present invention;

[0050] Figure 9 This is a schematic diagram of the three-airbag structure of the present invention;

[0051] Figure 10 This is a schematic diagram of the braking and positioning device of the present invention;

[0052] Figure 11 This is a schematic diagram of the drive rod structure of the present invention;

[0053] Figure 12This is a schematic diagram of the front drive disk structure of the present invention;

[0054] Figure 13 This is a schematic diagram of the rear drive disk structure of the present invention;

[0055] Figure 14 This is a schematic diagram of the positioning cover and positioning rod structure of the present invention;

[0056] Figure 15 This is a schematic diagram of the ball bearing structure of the present invention;

[0057] Figure 16 This is a schematic diagram of the groove structure of the present invention;

[0058] Figure 17 This is a schematic diagram of the installation of the transmission sealing ring of the present invention;

[0059] Figure 18 This is a schematic diagram of the O-ring installation of the present invention;

[0060] Figure 19 This is a schematic diagram of the installation of the Y-type sealing ring of the present invention.

[0061] Among them, 1-main body, 101-positioning ring platform, 102-long step, 103-threaded end hole, 104-inflation pipe, 105-transmission hole, 1041-inflation main hole, 1042-inflation branch hole, 1043-inflation nozzle, 1044-threaded cavity, 1045-bottom hole, 1046-nozzle sealing ring, 2-end cover, 201-threaded end, 202-center threaded hole, 3-annular airbag, 301-rotating flange, 302-protruding sealing ring, 4-mounting ring, 401-vent, 402-positioning boss, 403-mounting cavity, 404-limiting ring groove, 5-spacer ring, 6-safety valve, 601-perforated waist nut, 602-vent groove, 603-moving shaft, 604-chassis, 605-seal Cone head, 606-valve body sealing ring, 607-vent hole, 608-sealing spring, 609-fixed magnetic ring, 610-moving magnetic ring, 7-positioning cover, 701-mounting hole, 702-slide groove, 703-connecting screw, 704-air nozzle hole, 705-ball bearing, 8-positioning rod, 801-slide plate, 802-transmission rod, 803-slide sleeve, 804-limit nut, 805-elastic contact head, 9-drive disc, 901-limit hole, 902-drive arc groove, 903-air nozzle arc groove, 904-keyway, 10-drive rod, 1001-drive head, 1002-threaded section, 1003-spring, 11-transmission sealing ring, 1101-O-ring seal, 1102-Y-ring seal, 1103-wear-resistant ring. Detailed Implementation

[0062] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0063] The present invention will now be described in detail with reference to the accompanying drawings.

[0064] Example 1

[0065] like Figure 1 and Figure 2 As shown, an oil and gas pipeline sealing head includes a main body 1, an end cap 2, an annular airbag 3, and an installation ring 4. The main body 1 is a cylindrical structure. One end of the main body 1 is provided with a positioning ring platform 101. A long step 102 is formed on the inner side of the positioning ring platform 101. The long step 102 is used to fit the annular airbag 3. The other end of the main body 1 is provided with a threaded end hole 103. An inflation tube 104 is provided inside the main body 1. In this embodiment, two annular airbags 3 are arranged in series on the main body 1.

[0066] In the figure, the inflation tube 104 includes an axially arranged main inflation hole 1041 and two radially arranged secondary inflation holes 1042. An inflation nozzle 1043 is provided at the outer end of the main inflation hole 1041. An air nozzle sealing ring 1046 is fitted on the inflation nozzle 1043. The inner end of the main inflation hole 1041 is sealed. The inner end of the secondary inflation hole 1042 is connected to the main inflation hole 1041. The end cap 2 is installed in the threaded end hole 103 through the threaded end 201.

[0067] In the figure, two annular airbags 3 are fitted onto a long step 102. The two sides of the annular airbags 3 are limited by positioning rings 101 and end caps 2. Spacer rings 5 ​​are provided in front of multiple annular airbags 3. A 180° rotating flange 301 is provided at the inner opening of the annular airbag 3. The 180° rotating flange 301 includes an axial flange and a radial flange. A raised sealing ring 302 for contacting and sealing the tube wall is provided on the outer side of the annular airbag 3. The mounting ring 4 is fitted onto the long step 102 and is located inside the annular airbag 3. The mounting ring 4 is used to position and seal the annular airbag 3.

[0068] It should be noted that the surface of the mounting ring 4 is provided with a vent 401. The vent 401 is an arc-shaped opening with an angle range of 15° to 30°. The vent 401 is located on the inflation port 1042. A safety valve 6 or a one-way valve can be installed in the inflation port 1042. Alternatively, the valve body may not be installed in the inflation port 1042.

[0069] In the figure, a positioning boss 402 is provided in the middle of the inner wall of the mounting ring 4. The steps on both sides of the positioning boss 402 form a mounting cavity 403 for mounting the annular airbag 3. A limiting ring groove 404 is provided at the bottom of the mounting cavity 403. The limiting ring groove 404 is used to install the rotating flange of the annular airbag 3, such as... Figure 8 As shown.

[0070] In actual installation, firstly, the rotating flange 301 of the annular airbag 3 is fitted onto the mounting ring 4. Then, the annular airbag 3 and the mounting ring 4 are sequentially fitted onto the long step 102. Spacer rings 5 ​​are arranged at the intervals of the annular airbags 3. Next, the end cap 2 is tightened. At this time, both sides of the opening of each annular airbag 3 are compressed, and a seal is achieved under the action of the compression force. The sealing connection between the annular airbag and the internal mounting ring adopts a 180° rotating flange, which increases its contact surface and friction, and can significantly improve its sealing performance. Compared with the traditional 90° folding edge scheme, its airbag sealing internal pressure can be increased by more than 60%, which solves the technical problem that during the sealing process, the cross-section of the rubber airbag end face narrows due to the increase in internal pressure, causing the rubber airbag to easily fall off or leak and fail.

[0071] Example 2

[0072] like Figures 3 to 7As shown, the safety valve 6 includes a perforated waist-shaped nut 601, a vent groove 602, a movable shaft 603, a base 604, a sealing cone 605, a valve body sealing ring 606, a vent hole 607, a sealing spring 608, a fixed magnetic ring 609, and a moving magnetic ring 610. In the figure, the perforated waist-shaped nut 601 is installed in the threaded cavity 1044 at the top of the inflation port 1042. The waist of the perforated waist-shaped nut 601 forms a vent groove 602 between itself and the inner wall of the threaded cavity 1044. The top of the inflation port 1042 is tapped to form the threaded cavity 1044. The movable shaft 603 is movably installed in the central hole of the perforated waist-shaped nut 601. The outermost end of the movable shaft 603 does not extend beyond the end face of the perforated waist-shaped nut 601 to prevent the mounting ring 4 from being unable to be fitted. The base 604 is located at the bottom of the movable shaft 603, and a gap is formed between the base 604 and the inflation port 1042. The fit is such that the gap is 0.20mm to 1.50mm, ensuring that the chassis 604 can move up and down and preventing a large amount of liquid or gas from passing through the gap; the sealing cone 605 is set on the lower side of the chassis 604, and the size of the sealing cone 605 is the same as the size of the bottom hole 1045 of the inflation port 1042. The valve body sealing ring 606 is fitted on the sealing cone 605; the valve body sealing ring 606 fits tightly with the chassis 604 and is the same size. Multiple vent holes 607 are symmetrically opened around the periphery of the valve body sealing ring 606 and the chassis 604. In the figure, there are four vent holes 607. The sealing spring 608 is installed between the chassis 604 and the perforated waist nut 601; the fixed magnetic ring 609 is fitted on the moving shaft 603 and fixedly connected to the perforated waist nut 601; the moving magnetic ring 610 is fitted on the moving shaft 603 and fixedly connected to the chassis 604.

[0073] The working process is as follows: When no external force is applied, the fixed magnetic ring 609 and the moving magnetic ring 610 attract each other. The magnetic attraction force is greater than the elastic force of the sealing spring 608, and the sealing cone 605 moves away from the vent hole 1042. Figure 3 As shown. When the pressure inside the vent 401 suddenly increases, because the high-pressure liquid or gas cannot pass through the vent 607 in large quantities, a pressure side is formed. At this time, the side of the chassis 604 near the vent groove 602 experiences increased force. When the sum of the external pressure and the elastic force of the sealing spring 608 exceeds the magnetic attraction force, the fixed magnetic ring 609 and the moving magnetic ring 610 separate from each other, and the sealing cone 605 enters the bottom hole 1045 and cooperates with the valve body sealing ring 606 to complete the sealing of the vent hole 1042. Figure 9As shown. When it is necessary to restore the initial position, it is only necessary to increase the pressure of the main vent 1041. At this time, the force on the side of the chassis 604 near the bottom hole 1045 increases. When the sum of the internal pressure and the magnetic attraction force is greater than the elastic force of the sealing spring 608, the moving magnetic ring 610 moves upward until the fixed magnetic ring 609 and the moving magnetic ring 610 attract each other, and the sealing cone 605 moves away from the bottom hole 1045. In actual operation, when a certain annular airbag is damaged, high-pressure gas or liquid quickly enters the interior of the annular airbag. At this time, the internal safety valve is triggered, and the corresponding venting branch hole closes, achieving self-sealing. The dimensions of the sealing cone 605, venting groove 602, sealing spring 608, venting hole 607, etc., should be specifically designed based on the above working principle.

[0074] It should be noted that the threaded cavity 1044 and the vent hole 1045 are directly tapped and drilled on the main body 1, and are an integrated design. The safety valve 6 adopts an integrated structure with the main body 1, with a compact layout and good sealing performance. Even if a certain airbag is damaged due to burrs on the inner wall or scratches from foreign objects, the other airbags can still be sealed independently. For example, after the inner airbag is damaged, the outer airbag can still continue to be sealed due to the existence of the safety valve.

[0075] Example 3

[0076] like Figure 9 As shown, the oil and gas pipeline sealing head includes a main body 1, an end cap 2, three annular airbags 3, three mounting rings 4, two spacer rings 5, and three safety valves 6. In the figure, the sealing head adopts a three-airbag coaxial series arrangement and is equipped with safety valves, enabling it to adapt to medium and high pressure and complex environments. Its sealing pressure can reach 2.5 MPa. In practical applications, the size and number of annular airbags 3 can be flexibly adjusted.

[0077] Example 4

[0078] like Figures 10 to 16 As shown, it also includes positioning covers 7, telescopic positioning rods 8, drive discs 9 that drive the positioning rods 8, and drive rods 10 that drive the drive discs 9, all located at both ends of the main body 1. The front positioning cover 7 is fixed on the end face of the positioning ring platform 101, and the rear positioning cover 7 is located on the top of the end cover 2 and forms an integral structure with the end cover 2. The rear positioning cover 7 can be milled out on the top of the end cover 2 by a milling cutter. In the figure, the center of the positioning cover 7 is provided with a mounting hole 701, and three or four sliding grooves 702 are radially symmetrically arranged on the positioning cover 7. The bottom of the sliding groove 702 of the front positioning cover 7 is provided with a connecting screw 703, which is used to connect the positioning cover 7 and the main body 1. The front positioning cover 7 is provided with an air nozzle hole 704 for installing an air nozzle 1043.

[0079] Figure 11In this design, the positioning rod 8 includes a sliding plate 801 and a transmission rod 802. The sliding plate 801 is movably installed in the slide groove 702. The transmission rod 802 is vertically set at the bottom of the sliding plate 801. A sliding sleeve 803 is fitted on the transmission rod 802. A limit nut 804 is installed on the top of the transmission rod 802. An elastic contact head 805 is wrapped around the outside of the sliding plate 801. Specifically, the sliding plate 801 and the slide groove 702 form a slot and slider structure. After the sliding plate 801 is installed from the top, it can only move along the slide groove 702 and cannot detach from the slide groove 702. In actual operation, one or more balls 705 are provided at the bottom of the slide groove 702 near the outer end to reduce the moving friction of the driving positioning rod 8.

[0080] In the figure, a limiting hole 901 is provided in the middle of the drive disk 9. Three or four drive arc grooves 902 are symmetrically arranged on the drive disk 9. The drive arc grooves 902 are fitted onto the sliding sleeve 803 and are positioned by the limiting nut 804. The drive disk 9 is also provided with an air nozzle arc groove 903 for installing the air nozzle 1043. Specifically, during the process of the drive disk 9 rotating at a constant speed from 35° to 55°, the sliding sleeve 803 also moves from the bottom end to the top end. The envelope of the projection of the outer contour of the sliding sleeve 803 onto the drive disk 9 forms the inner contour of the drive arc groove 902. The air nozzle arc groove 903 is arranged concentrically with the drive disk 9, and the angle range of the air nozzle arc groove 903 is from 35° to 55°.

[0081] In actual operation, the drive rod 10 passes sequentially through the limiting hole 901 of the front drive disc 9, the mounting hole 701 of the front positioning cover 7, the transmission hole 105 of the main body 1, the center threaded hole 202 of the end cover 2, the mounting hole 701 of the rear positioning cover 7, and the limiting hole 901 of the rear drive disc 9. The rotation of the drive rod 10 can synchronously drive the rotation of the front drive disc 9 and the rear drive disc 9, and drive the drive arc groove 902 to rotate so as to drive the positioning rod 8 to move back and forth synchronously along the slide groove 702. In the figure, the dimensions of the positioning rod 8 and the drive disc 9 are consistent.

[0082] During the sealing operation, the sealing head is first placed into the pipe, and the drive rod is rotated. The drive rod can synchronously drive the front and rear drive discs to rotate. The synchronous rotation of the drive discs utilizes the interaction between the drive arc groove and the positioning rod to drive the positioning rod to extend synchronously until the end of the drive rod is in close contact with the pipe wall. At this time, the stop device can not only increase the overall friction of the airbag and effectively prevent its overall slippage, but also keep its axis stable and not deviated when the airbag is sealed and expanded, ensuring that the contact surface between the airbag and the inner wall of the pipe is symmetrical and the force is uniform, thereby improving the overall pressure bearing capacity.

[0083] It should be noted again that, in order to ensure that the drive disc 9 and the drive rod 10 rotate synchronously, a keyway 904 is provided on the limiting hole 901 of the drive disc 9. The keyway 904 engages with the spline on the drive rod 10 for transmission. A drive head 1001 can also be provided at the end of the drive rod 10. The drive head 1001 is hexagonal or octagonal. Both ends of the drive rod 10 are provided with threaded sections 1002. The front threaded section 1002 is threaded to the mounting hole 701, and the rear threaded section 1002 is threaded to the center threaded hole 202. A spring 1003 can also be provided between the drive head 1001 and the front drive disc 9. The spring 1003 can increase the preload of the positioning rod 8, prevent accidental rotation, ensure that the drive rod 10 extends reliably, and ensure the stability of the sealing head's axis.

[0084] Example 5

[0085] like Figure 18 and Figure 19 As shown, one or more transmission sealing rings 11 are fitted in the middle of the drive rod 10. The transmission sealing rings 11 are used to dynamically seal the gap between the drive rod 10 and the transmission hole 105. The transmission sealing rings 11 include O-rings 1101, Y-rings 1102, or high-pressure sealing rings 1104. This sealing solution can effectively prevent oil and gas leakage inside the pipeline at a low cost.

[0086] Specifically, a Y-shaped sealing ring 1102 and a wear-resistant ring 1103 are fitted in the middle of the drive rod 10. The Y-shaped sealing ring 1102 is divided into a first Y-shaped sealing ring and a second Y-shaped sealing ring. The first Y-shaped sealing ring and the second Y-shaped sealing ring are arranged opposite each other, with the opening of the first Y-shaped sealing ring facing outward and the opening of the second Y-shaped sealing ring facing inward. The wear-resistant ring 1103 is set in the middle of the first Y-shaped sealing ring and the second Y-shaped sealing ring. In the figure, a new sealing scheme is arranged between the drive rod and the main transmission hole of the sealing head. The sealing scheme uses wear-resistant rings and multiple sealing rings to improve its sealing performance and coaxiality. It can effectively prevent oil and gas leakage inside the pipeline with a low-cost solution. The wear-resistant ring is made of nylon material, which not only has high wear resistance but also has a certain lubrication effect.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pipe-line pig head, c h a r a c t e r i s e d in that The utility model relates to a kind of air cylinder, including main body (1), end cover (2), annular air bag (3) and mounting ring (4), wherein: The main body (1) is cylindrical structure, one end of main body (1) is provided with positioning ring table (101), long step (102) is formed in the inside of positioning ring table (101) of main body (1), the other end of main body (1) is provided with threaded end hole (103), the inside of main body (1) is provided with inflation pipe (104); The inflation pipe (104) includes axially arranged inflation main hole (1041) and radially arranged inflation branch hole (1042), the outer end of the inflation main hole (1041) is provided with an inflation nozzle (1043), the inflation nozzle (1043) is sleeved with an air nozzle sealing ring (1046), the inner end of the inflation main hole (1041) is sealed, and the inner end of the inflation branch hole (1042) is communicated with the inflation main hole (1041); The end cover (2) is installed in the threaded end hole (103) through a threaded end (201); A plurality of annular air bags (3) are sleeved on the long step (102), the two sides of the annular air bag (3) are limited by the positioning ring table (101) and the end cover (2), a plurality of annular air bags (3) are provided with a spacing ring (5) in front, the inside of the annular air bag (3) is provided with a 180° rotary flange (301) at the opening, and the outside of the annular air bag (3) is provided with a convex sealing ring (302) for contacting the pipe wall; The mounting ring (4) is sleeved on the long step (102) and located in the inside of the annular air bag (3), and the mounting ring (4) is used for positioning and sealing the annular air bag (3); The surface of the mounting ring (4) is provided with a vent (401), the vent (401) is located on the inflation branch hole (1042), the inner wall of the mounting ring (4) is provided with a positioning boss (402) in the middle, the steps on both sides of the positioning boss (402) form a mounting cavity (403) for mounting the annular air bag (3), and the bottom of the mounting cavity (403) is provided with a limiting ring groove (404) for mounting the rotary flange of the annular air bag (3); Further comprising a safety valve (6), the safety valve (6) is installed in the inflation branch hole (1042) and comprises a hole waist nut (601), a vent groove (602), a moving shaft (603), a bottom disc (604), a sealing cone head (605), a valve body sealing ring (606), a vent hole (607), a sealing compression spring (608), a fixed magnetic ring (609) and a moving magnetic ring (610), wherein: The hole waist nut (601) is installed in the threaded cavity (1044) at the top of the inflation branch hole (1042), and the waist part of the hole waist nut (601) and the inner wall of the threaded cavity (1044) form the vent groove (602); The moving shaft (603) is movably installed in the middle hole of the hole waist nut (601); The bottom disc (604) is arranged at the bottom of the moving shaft (603), and the gap between the bottom disc (604) and the inflation branch hole (1042) is 0.20mm to 1.50mm. The sealing cone head (605) is arranged on the lower side of the bottom disc (604), the size of the sealing cone head (605) is consistent with the size of the bottom hole (1045) of the inflation hole (1042), and the sealing cone head (605) is sleeved with a valve body sealing ring (606); The valve body sealing ring (606) is tightly attached to the bottom disc (604) and has a consistent size, and a plurality of air holes (607) are symmetrically arranged on the periphery of the valve body sealing ring (606) and the bottom disc (604); The sealing compression spring (608) is installed between the bottom disc (604) and the hole waist nut (601); The fixed magnetic ring (609) is sleeved on the moving shaft (603) and is fixedly connected with the hole waist nut (601); The moving magnetic ring (610) is sleeved on the moving shaft (603) and is fixedly connected with the bottom disc (604); The fixed magnetic ring (609) and the moving magnetic ring (610) have opposite poles and attract each other.

2. The pipe-line operation blind head according to claim 1, characterized in that Further comprising positioning covers (7) arranged at both ends of the main body (1), telescopic positioning rods (8), drive discs (9) driving the movement of the positioning rods (8), and drive rods (10) driving the movement of the drive discs (9), wherein: The front positioning cover (7) is fixed on the end face of the positioning ring table (101), and the rear positioning cover (7) is arranged on the top of the end cover (2) and forms an integral structure with the end cover (2); A mounting hole (701) is arranged at the center of the positioning cover (7), three or four sliding grooves (702) are symmetrically arranged on the positioning cover (7) in the radial direction, a connecting screw (703) is arranged at the bottom of the sliding groove (702) of the front positioning cover (7), the connecting screw (703) is used for connecting the positioning cover (7) and the main body (1), and an air nozzle hole (704) for mounting an inflation nozzle (1043) is arranged on the front positioning cover (7); The positioning rod (8) comprises a sliding plate (801) and a transmission rod (802), the sliding plate (801) is movably installed in the sliding groove (702), the transmission rod (802) is vertically arranged at the bottom of the sliding plate (801), a sliding sleeve (803) is sleeved on the transmission rod (802), a limiting nut (804) is arranged at the top of the transmission rod (802), and an elastic contact head (805) is wrapped on the outside of the sliding plate (801); A limiting hole (901) is arranged at the middle of the drive disc (9), three or four drive arc grooves (902) are symmetrically arranged on the drive disc (9), the drive arc groove (902) is sleeved on the sliding sleeve (803) and is positioned by the limiting nut (804), and an air nozzle arc groove (903) for mounting the inflation nozzle (1043) is further arranged on the drive disc (9); The driving rod (10) sequentially passes through the limiting hole (901) of the front driving disc (9), the mounting hole (701) of the front positioning cover (7), the transmission hole (105) of the main body (1), the central threaded hole (202) of the end cover (2), the mounting hole (701) of the rear positioning cover (7) and the limiting hole (901) of the rear driving disc (9), and the rotation of the driving rod (10) can synchronously drive the rotation of the front driving disc (9) and the rear driving disc (9) and drive the rotation of the driving arc groove (902) to drive the positioning rod (8) to move forward and backward along the sliding groove (702).

3. The pipe-line operation blind head according to claim 2, characterized in that One or more balls (705) are arranged at the position close to the outer end of the bottom of the sliding groove (702), so as to reduce the moving friction of the driving positioning rod (8).

4. The pipeline pigging plug of claim 2, wherein, The limiting hole (901) of the driving disc (9) is provided with a key groove (904), and the key groove (904) is matched with the spline on the driving rod (10) to drive.

5. The pipe-line operation blind head according to claim 2, characterized in that, During the uniform rotation of the driving disc (9) by 35° to 55°, the sliding sleeve (803) also moves from the bottom end to the top end, and the envelope line of the projection of the outer contour of the sliding sleeve (803) on the driving disc (9) forms the inner contour of the driving arc groove (902).

6. The pipe-line operation blind head according to claim 2, characterized in that The air nozzle arc groove (903) is arranged concentrically with the driving disc (9).

7. The pipe-line operation blind head according to claim 2, characterized in that The end of the driving rod (10) is provided with a driving head (1001), the two ends of the driving rod (10) are provided with threaded segments (1002), and the driving head (1001) and the front driving disc (9) are provided with a spring (1003).

8. The pipe-line operation blind head according to claim 2, characterized in that, The middle part of the driving rod (10) is sleeved with one or more transmission sealing rings (11), and the transmission sealing ring (11) is used for dynamically sealing the gap between the driving rod (10) and the transmission hole (105).

9. The pipe-line operation blind head according to claim 8, characterized in that The transmission sealing ring (11) is an O-shaped sealing ring (1101) or a Y-shaped sealing ring (1102).

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