Self-sealing bush

Abstract

The invention discloses a self-sealing lining, and relates to the technical field of oil pipes. The self-sealing lining comprises a central tube, a sealing sleeve and a sealing sleeve, the central tube is composed of a tubular body and a diameter expanding part, and the diameter expanding part is arranged in the middle of the tubular body and protrudes towards the outer side of the tubular body; the middle sleeve is arranged outside the expanding part in a sleeving mode and used for blocking heat conduction at the joint of the two oil pipes, the middle sleeve comprises a carrying frame, the carrying frame is provided with a plurality of sets of separated annular spaces, sealing layers are arranged in the peripheries of the annular spaces, heat insulation layers are arranged on the sealing layers, and the sealing layers are made of thermal expansion materials; the carrying frame is used for limiting axial expansion of the sealing layer and forming multi-ring sealing; according to the self-sealing lining, the carrying frame is arranged, the sealing layer is divided into multiple circles, the strength of the sealing layer is improved, meanwhile, axial limiting can be conducted on expansion of each circle of sealing layer, and the radial expansion amount of the sealing layer is further improved.

Description

Technical Field

[0001] This invention relates to the field of tubing technology, specifically to a self-sealing bushing. Background Technology

[0002] In existing technologies, high-temperature steam heating is commonly used for heavy oil extraction. However, heat loss occurs during steam transport in insulated oil pipes. Specifically, oil pipes using heating technology suffer significant heat loss due to poor insulation. Furthermore, offshore oil extraction is more challenging than onshore extraction. Therefore, improving the insulation capacity of insulated oil pipes is crucial, as it directly impacts their effective service life.

[0003] One of the main reasons for the shortened effective working time of insulated oil pipes is the significant heat loss at the pipe joints. Although vacuum insulated oil pipes are commonly used in existing technologies, vacuum insulation cannot be achieved at the joints of adjacent oil pipes. Furthermore, the existing insulation structures are inadequate and have high thermal conductivity, resulting in a short effective working time for the insulated oil pipes and increasing production costs.

[0004] To address this issue, a novel heat-insulating bushing was proposed in patent CN210343257U. This bushing solves the problem by setting up a heat-insulating sleeve and a sealing sleeve that expands upon heating (raw graphite, metal wire, asbestos). However, the strength of the expansion material is relatively low, making it prone to damage and breakage. Furthermore, the expansion material in the prior art is prone to axial expansion due to the lack of stratification. Excessive axial expansion can affect the sealing effect. In addition, it only seals the inner circumferential wall of the oil pipe, resulting in a small sealing area and fewer sealing procedures. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a self-sealing bushing, which solves the problems of low strength and easy crushing of the expansion material when using heat insulation sleeves and thermally expanding (raw graphite, metal wire, asbestos) sealing sleeves in existing technologies. Furthermore, the expansion material in existing technologies is prone to axial expansion due to its lack of stratification, and excessive axial expansion can affect the sealing effect. In addition, it only seals the inner circumferential wall of the oil pipe, resulting in a small sealing area and fewer sealing procedures.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a self-sealing bushing, comprising: The central tube is composed of a tubular body and an enlarged diameter portion located in the middle of the tubular body and protruding outward from the tubular body. An intermediate sleeve, which is fitted outside the enlarged diameter section, is used to block heat conduction at the junction of the two oil pipes. The intermediate sleeve includes a carrier frame having multiple sets of spaced annular spaces, a sealing layer around the annular spaces, and a heat insulation layer on the sealing layer. The sealing layer is made of a thermally expanding material. The carrier frame is used to limit the axial expansion of the sealing layer and to form multiple seals. Both the second oil pipe and the first oil pipe have a centripetal bent retaining ring at their joint ends. The sealing layer is close to the annular space, and the sealing layer in the middle is provided with a notch that matches the retaining ring. The carrier has a pressure-deformable structure on the side near the retaining ring. When the sealing layer expands, the pressure-deformable structure can press against the retaining ring to form a radial seal between oil pipe two and oil pipe one.

[0007] Furthermore, the sealing layer is a molded graphite packing or a molded composite ceramic fiber.

[0008] Furthermore, the carrier includes: A cylindrical frame, wherein the cylindrical frame has end frames at both ends; The ring frame has two sets, and the two sets of ring frames are located in the area near both ends of the cylinder frame. The two sets of ring frames divide the space on the cylinder frame into three parts. The heat insulation layer is located on the side close to the cylinder frame, and the sealing layer is located on the side away from the cylinder frame. The cylinder frame, ring frame and end frame are all rigid structures used to restrict the axial expansion of the sealing layer.

[0009] Furthermore, the notch is located on both sides of the outer periphery of the sealing layer between the two ring frames, and the retaining ring is located inside the notch; The compressible deformable structure includes: The ring frame has a conical surface on its periphery, and a wedge-shaped ring is provided on the periphery of the conical surface; the radial expansion of the sealing layer is used to seal the circumferential inner wall of oil pipe two and oil pipe one, and the expansion of the sealing layer is also used to compress the wedge-shaped ring, so that the wedge-shaped ring can simultaneously seal the circumferential and radial aspects of oil pipe two and oil pipe one.

[0010] Furthermore, a compensation ring is provided between the connection ends of oil pipe 2 and oil pipe 1.

[0011] Furthermore, the carrier includes: The corrugated frame has a heat insulation layer filling the cavity of the corrugated frame. The cavity divides the sealing layer into multiple parallel layers, allowing the sealing layer to expand in multiple turns along the oil pipe axis. The corrugated frame has end frames at both ends. The end frame is used to limit the axial expansion of the sealing layer.

[0012] Furthermore, the central wave is an elastic ring structure with a U-shaped cross-section. This elastic ring structure forms a deformable structure under pressure. The insulation layer inside the U-shaped cavity has a notch, and the retaining ring is located inside the notch.

[0013] Furthermore, it also includes end sleeves, which are fitted onto the tubular body and located at both ends of the expanded diameter portion. The two ends of the intermediate sleeve abut against the end faces of the end sleeves. The end sleeves include a metal skeleton and a thermal expansion sealing layer molded on and wrapping the metal skeleton.

[0014] Furthermore, the metal frame has a hollow area, and the metal frame is filled with a thermal expansion sealing layer.

[0015] Furthermore, the metal frame has a threaded ring at one end near the thermal expansion sealing layer, and the end face of the end frame is provided with a threaded groove that matches the threaded ring.

[0016] The present invention has the following beneficial effects: (1) The self-sealing bushing forms multiple rings of sealing layer by setting a carrier frame. While improving the strength of the sealing layer, it can also axially limit the expansion of each ring of sealing layer, further increasing its radial expansion. In addition, since the metal ring between the two rings of sealing layer will not expand radially after the sealing layer expands, there is no contact between the two adjacent rings of sealing layer, thus forming a multi-segment seal. Once the front sealing fails to absorb oil, the rear sealing can continue to seal.

[0017] (2) The self-sealing bushing is equipped with a pressure-deformable structure and a matching retaining ring is provided on the oil pipe. Therefore, after the sealing layer expands, the pressure-deformable structure can be changed. This change can seal the inner wall of the oil pipe on the one hand, and press on the retaining ring on the other hand, so that the oil pipe end has an additional seal and the sealing effect is enhanced.

[0018] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0019] Figure 1 This is an external view of the present invention; Figure 2 This is a schematic diagram of the structure of the central tube of the present invention; Figure 3 This is a schematic diagram of the internal structure of Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the carrier structure in Embodiment 1 of the present invention; Figure 5 This is an assembly drawing of the oil pipe and oil pipe sleeve in Embodiment 1 of the present invention; Figure 6 For the present invention Figure 5 A three-dimensional image; Figure 7 For the present invention Figure 6 Enlarged view of area A; Figure 8 For the present invention Figure 4 Exploded view; Figure 9 For the present invention Figure 4 Cross-sectional view; Figure 10 This is a schematic diagram of the end sleeve of the present invention; Figure 11 For the present invention Figure 10 Exploded view; Figure 12 This is a schematic diagram of the metal frame of the present invention using a rectangular hollow area; Figure 13 This is a schematic diagram of the internal structure of Embodiment 2 of the present invention; Figure 14 This is an assembly diagram of the oil pipe and oil pipe sleeve in Embodiment 2 of the present invention.

[0020] In the diagram, 100 is the central tube; 110 is the tubular body; 120 is the enlarged section; 200 is the end sleeve; 210 is the thermal expansion sealing layer; 220 is the metal skeleton; 221 is the threaded ring; 222 is the hollow area; 300 is the intermediate sleeve; 310 is the carrier; 311 is the cylinder frame; 312 is the ring frame; 313 is the wedge ring; 314 is the end frame; 315 is the corrugated frame; 320 is the heat insulation layer; 330 is the sealing layer; 340 is the notch; 400 is the second oil pipe; 500 is the casing coupling; 600 is the first oil pipe; 700 is the compensation ring; and 800 is the retaining ring. Detailed Implementation

[0021] 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.

[0022] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0023] The following is based on Figures 1-14 This invention describes a self-sealing bushing provided in an embodiment of the invention.

[0024] Example 1: Please refer to Figures 1-3 This invention provides a self-sealing bushing, comprising a central tube 100, an end sleeve 200, and an intermediate sleeve 300.

[0025] like Figure 2 The central tube 100 consists of a tubular body 110 and an enlarged diameter portion 120 located in the middle of the tubular body 110 and protruding outward from the tubular body 110. The cross-section of the enlarged diameter portion 120 along the axis of the tubular body 110 is trapezoidal.

[0026] There are two end sleeves 200, which are provided on the tubular body 110, located at both ends of the enlarged diameter section 120, and are symmetrically arranged on both sides of the enlarged diameter section 120. Preferably, there is a gap between the end sleeves 200 and the enlarged diameter section 120.

[0027] The intermediate sleeve 300 is fitted outside the enlarged diameter section 120. Preferably, the two are interference fit. The axial length of the inner wall of the intermediate sleeve 300 is greater than or equal to the axial length of the outer wall of the tubular body 110. The intermediate sleeve 300 is used to block heat conduction at the junction of the two oil pipes. The two ends of the intermediate sleeve 300 abut against the end face of the end sleeve 200 to avoid the formation of a sealing section.

[0028] Reference Figure 4 In this embodiment of the invention, the outer ring surface of the self-sealing bushing contacts the inner walls of oil pipe 600 and oil pipe 400. The self-sealing structure is formed by the pressure generated by the central tube 100, the male and female threaded ends of the two sets of oil pipes, and the inner wall of the sleeve coupling 500 on the self-sealing bushing. After self-sealing, the intermediate sleeve 300 located in the central area where the two sets of oil pipes meet can isolate internal and external heat to the maximum extent, and solve the sealing and heat insulation problems of the oil pipe coupling to the maximum extent. In addition, since the central tube 100 directly isolates a large amount of oil from direct contact with the end sleeve 200 and the intermediate sleeve 300 in this invention, the situation of slag falling off after a long time when using graphite sheet sealing in the prior art will not occur.

[0029] Preferably, the intermediate sleeve 300 includes a carrier 310, which has multiple sets of spaced annular spaces. A sealing layer 330 is provided around the annular spaces, and a heat insulation layer 320 is provided on the sealing layer 330. The sealing layer 330 is made of a thermally expanding material.

[0030] Therefore, the carrier 310 provided in this embodiment of the invention is used to limit the axial expansion of the sealing layer 330 and further increase its radial expansion. It can also be used to form a multi-ring seal. In addition, since the metal ring between the two sealing layers 330 will not expand radially after the sealing layer 330 expands, there is no contact between the two adjacent sealing layers 330, so a multi-segment seal can be formed. Once the front sealing fails to absorb oil, the rear sealing can continue to seal.

[0031] In addition, in order to increase the sealing area, the mating ends of oil pipe 2 400 and oil pipe 1 600 are both equipped with a centripetally bent retaining ring 800. The sealing layer 330 is close to the annular space, and the middle sealing layer 330 is provided with a notch 340 that is adapted to the retaining ring 800. The carrier 310 is provided with a pressure-deformable structure on the side near the retaining ring 800. When the sealing layer 330 expands, the pressure-deformable structure can be pressed against the retaining ring 800, forming a radial surface seal between oil pipe 2 400 and oil pipe 1 600.

[0032] In this embodiment, retaining rings 800 that match the pressure-deformable structure are provided on oil pipe 2 400 and oil pipe 1 600. Therefore, after the sealing layer 330 expands, the pressure-deformable structure can be changed. This change can seal the inner wall of the oil pipe on the one hand, and press on the retaining ring on the other hand, so that the oil pipe end has an additional seal and the sealing effect is enhanced.

[0033] Combination Figures 3-9 As shown, specifically, in this embodiment, the carrier 310 includes a cylindrical frame 311 and a ring frame 312. The cylindrical frame 311 has end frames 314 at both ends. There are two sets of ring frames 312, and the two sets of ring frames 312 are located in the area near both ends of the cylindrical frame 311. The two sets of ring frames 312 divide the space on the cylindrical frame 311 into three parts. The heat insulation layer 320 is located on the side close to the cylindrical frame 311, and the sealing layer 330 is located on the side away from the cylindrical frame 311. The cylindrical frame 311, the ring frame 312, and the end frames 314 are all rigid structures used to restrict the axial expansion of the sealing layer 330.

[0034] In addition, the notch 340 is located on both sides of the outer periphery of the sealing layer 330 between the two ring frames 312, and the retaining ring 800 is located inside the notch 340; the pressure-deformable structure includes: a conical surface is provided on the outer periphery of the ring frame 312, and a wedge-shaped ring 313 is provided on the outer periphery of the conical surface.

[0035] Therefore, the radial expansion of the sealing layer 330 is used to seal the circumferential inner walls of the second oil pipe 400 and the first oil pipe 600. The expansion of the sealing layer 330 is also used to compress the wedge ring 313, causing the wedge ring 313 to move under pressure. This movement provides synchronous circumferential and radial sealing for the second oil pipe 400 and the first oil pipe 600.

[0036] Preferably, in order to fill the gap between the second oil pipe 400 and the first oil pipe 600, a compensation ring 700 is provided between the mating ends of the second oil pipe 400 and the first oil pipe 600. The compensation ring 700 is preferably a high-temperature resistant metal ring.

[0037] In this embodiment, the carrier 310 is made of a heat-resistant metal, such as a titanium-based composite material with added ceramic particles.

[0038] For the insulation layer 320, it is preferably made of aerogel material.

[0039] For the sealing layer 330: the sealing layer 330 is made of a thermally expanding material. Optionally, the expanding material of the sealing layer 330 is a molded graphite packing or a molded composite ceramic fiber.

[0040] Taking molded graphite packing as an example, its manufacturing steps are as follows: Step 1: Mix the chopped graphite fibers with a binder (such as phenolic resin); Step 2: Place the carrier 310 carrying the heat insulation layer 320 into the mold, and feed the space between the carrier 310 and the mold with a mixture of chopped graphite fibers and binder (such as phenolic resin), and pre-form it under cold pressure of 20-50 MPa. Step 3: High-temperature carbonization (700-800℃) removes the binder and forms a porous structure.

[0041] Step four, secondary impregnation (such as with asphalt) to increase density.

[0042] The aforementioned end sleeve 200 includes a metal frame 220 and a thermal expansion sealing layer 210 molded on and wrapped around the metal frame 220. The metal frame 220 is made of the same material as the carrier 310 in this embodiment and is used to support the thermal expansion sealing layer 210 and improve the strength of the thermal expansion sealing layer 210.

[0043] Optionally, the thermal expansion sealing layer 210 is made of a thermal expansion material, such as molded graphite packing or nickel wire graphite fiber braid.

[0044] Combination Figures 10-12 As shown, further, in order to improve the connection performance of the thermal expansion sealing layer 210 inside and outside the metal frame 220 (i.e., the integrity and stability of the two thermal expansion sealing layers 210), the metal frame 220 has a hollow area 222, and the metal frame 220 is filled with the thermal expansion sealing layer 210, so that the inner and outer thermal expansion sealing layers 210 are essentially an integral structure.

[0045] The hollow area 222 is a circular through hole or a rectangular hole.

[0046] Preferably, the metal frame 220 has a threaded ring 221 at one end near the thermal expansion sealing layer 210, and the end face of the end frame 314 is provided with a threaded groove that matches the threaded ring 221, so as to facilitate the connection between the two.

[0047] Example 2: Please refer to Figures 13-14As shown, the difference between this embodiment and Embodiment 1 is that the carrier 310 includes a corrugated frame 315, and the heat insulation layer 320 is filled in the corrugated cavity of the corrugated frame 315. The corrugated cavity divides the sealing layer 330 into multiple parallel layers, which allows the sealing layer 330 to form multiple turns of expansion along the oil pipe axis. The corrugated frame 315 has end frames 314 at both ends. The end frames 314 are used to restrict the axial expansion of the sealing layer 330.

[0048] Therefore, in the embodiments of the present invention, the purpose of limiting axial expansion and multi-ring sealing can also be achieved.

[0049] Preferably, the middle wave is an elastic annular structure with a U-shaped cross-section. The elastic annular structure forms a deformable structure under pressure. The heat insulation layer 320 inside the U-shaped cavity has a notch 340, and the retaining ring 800 is located inside the notch 340. This allows the sealing layers 330 on both sides of the middle wave to expand and compress the U-shaped structure, causing the U-shaped structure to press on the retaining ring 800, achieving radial sealing, adding a sealing step, and expanding the sealing area.

[0050] For the carrier 310: its central wave is made of a deformable metal material, such as spring steel or stainless steel, while the rest is made of a heat-resistant metal ring, and the two can be connected by welding.

[0051] Since the carrier 310, except for the middle wave, will not deform and is blocked by the end sleeve 200, the sealing layer 330 can form multiple rings of expansion in the radial direction of the cavities of the wave crests and troughs. The formed multiple rings of expansion sites can form multiple rings of seals on both the inner and outer rings of the sealing layer 330.

[0052] Preferably, the insulation layer 320 is made of aerogel insulation material, which has strong high temperature resistance and high pressure resistance.

[0053] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0054] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A self-sealing bushing characterized by, include: The central tube (100) is composed of a tubular body (110) and an enlarged diameter portion (120) located in the middle of the tubular body (110) and protruding outward from the tubular body (110). Intermediate sleeve (300), which is fitted outside the enlarged diameter section (120) to block heat conduction at the junction of the two oil pipes; The intermediate sleeve (300) includes a carrier (310) having multiple sets of spaced annular spaces, a sealing layer (330) being provided around the annular spaces, and a heat insulation layer (320) being provided on the sealing layer (330). The sealing layer (330) is made of a thermally expanding material. The carrier (310) is used to limit the axial expansion of the sealing layer (330) and to form multiple seals. Both the second oil pipe (400) and the first oil pipe (600) have a centripetally bent retaining ring (800) at their connecting ends. The sealing layer (330) is close to the annular space, and the middle sealing layer (330) has a notch (340) that matches the retaining ring (800). The carrier (310) has a pressure-deformable structure on the side near the retaining ring (800). When the sealing layer (330) expands, the pressure-deformable structure can press against the retaining ring (800) to form a radial surface seal between the second oil pipe (400) and the first oil pipe (600).

2. A self sealing liner sleeve according to claim 1, wherein, The sealing layer (330) is a molded graphite packing or a molded composite ceramic fiber.

3. The self-sealing bushing according to claim 1, characterized in that, The carrier (310) includes: A tube frame (311) has end frames (314) at both ends. The ring frame (312) is provided in two sets, and the two sets of ring frames (312) are located in the area near both ends of the cylindrical frame (311). The two sets of ring frames (312) divide the space on the cylindrical frame (311) into three parts. The heat insulation layer (320) is located on the side close to the cylindrical frame (311), and the sealing layer (330) is located on the side away from the cylindrical frame (311). The cylindrical frame (311), the ring frame (312) and the end frame (314) are all rigid structures used to restrict the axial expansion of the sealing layer (330).

4. A self-sealing bushing according to claim 3, characterized in that, The notch (340) is located on both sides of the outer periphery of the sealing layer (330) between the two ring frames (312), and the retaining ring (800) is located inside the notch (340); The compressible deformable structure includes: The ring frame (312) has a conical surface on its periphery, and a wedge ring (313) is provided on the periphery of the conical surface; the sealing layer (330) expands radially to seal the circumferential inner wall of oil pipe two (400) and oil pipe one (600), and the expansion of the sealing layer (330) also squeezes the wedge ring (313) so that the wedge ring (313) synchronously seals the circumferential and radial aspects of oil pipe two (400) and oil pipe one (600).

5. A self-sealing bushing according to claim 4, characterized in that, A compensation ring (700) is also provided between the connecting ends of oil pipe 2 (400) and oil pipe 1 (600).

6. A self-sealing bushing according to claim 1, characterized in that: The carrier (310) includes: The wave frame (315) is filled with the heat insulation layer (320) in the wave cavity of the wave frame (315). The wave cavity divides the sealing layer (330) into multiple parallel layers, which will enable the sealing layer (330) to form multiple turns of expansion along the oil pipe axis; the two ends of the wave frame (315) have end frames (314). The end bracket (314) is used to limit the axial expansion of the sealing layer (330).

7. A self-sealing bushing according to claim 6, characterized in that: The middle wave is an elastic ring structure with a U-shaped cross section. The elastic ring structure forms a deformable structure under pressure. The heat insulation layer (320) inside the U-shaped cavity has a notch (340), and the retaining ring (800) is located inside the notch (340).

8. A self-sealing bushing according to any one of claims 2-6, characterized in that: It also includes an end sleeve (200), which is fitted onto the tubular body (110) and located at both ends of the enlarged diameter portion (120). The two ends of the intermediate sleeve (300) abut against the end face of the end sleeve (200). The end sleeve (200) includes a metal skeleton (220) and a thermal expansion sealing layer (210) molded on the metal skeleton (220) and wrapping the metal skeleton (220).

9. A self-sealing bushing according to claim 8, characterized in that: The metal frame (220) has a hollow area (222), and the metal frame (220) is filled with a thermal expansion sealing layer (210).

10. A self-sealing bushing according to claim 9, characterized in that: The metal frame (220) has a threaded ring (221) at one end near the thermal expansion sealing layer (210), and the end face of the end frame (314) is provided with a threaded groove that matches the threaded ring (221).

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