Thermal expansion compensation device for oil and gas pipeline

Abstract

The invention belongs to the technical field of pipe fitting connection, and particularly relates to an oil and gas pipeline thermal expansion compensation device which comprises a telescopic pipe, a guide rod, an inner core pipe, a compensation component and a wedge angle ring sleeve. A double-layer isolation design is formed through the inner core pipe and the corrugated pipe; a four-stage sealing system is sequentially achieved through cooperation of a sealing rubber ring, a sealing rubber ring, a sealing washer and an annular wedge face clamping ring, air pressure balance is automatically adjusted through a polyelectrolyte solution annular rubber ring, a fluid path is optimized in combination with a wedge angle ring sleeve, and the corrosion resistance, the sealing performance and the compensation capacity are remarkably improved. The corrugated pipe effectively solves the problems that a traditional corrugated pipe is prone to corrosion and poor in pressure resistance, is particularly suitable for oil and gas conveying pipelines of high-pressure corrosive media, and has the advantages of being long in service life and low in maintenance cost.

Description

Technical Field

[0001] This invention belongs to the field of pipe connection technology, and particularly relates to a thermal expansion compensation device for oil and gas pipelines. Background Technology

[0002] In the process of oil and gas resource extraction, transportation, and processing, oil and gas pipelines serve as crucial transport carriers, and their safe and stable operation directly affects the continuity and economy of energy supply. However, when transporting media, oil and gas pipelines are inevitably affected by factors such as changes in medium temperature (e.g., heated transport of crude oil, throttling and cooling of natural gas), fluctuations in ambient temperature, and the pipeline's own operating conditions, which inevitably lead to thermal expansion and contraction, resulting in axial or lateral displacement.

[0003] If these displacements are not effectively compensated, the pipeline will be subjected to enormous thermal stress. Over the long term, this could lead to problems such as pipeline bending and deformation, joint sealing failure, and weld cracking, and even serious safety accidents such as oil and gas leaks and explosions. This would not only cause huge economic losses but also pose a serious threat to the ecological environment. Therefore, equipping oil and gas pipelines with reliable thermal expansion compensation devices to alleviate thermal stress and absorb displacement has become a crucial aspect of ensuring the safe operation of oil and gas pipeline systems.

[0004] Currently, commonly used thermal expansion compensation devices in oil and gas pipelines include natural compensation devices, bellows compensators, sleeve compensators, and spherical compensators. Bellows compensators are widely used in oil and gas pipelines due to their strong compensation capacity and compact structure. However, their core component, the bellows, is made of thin-walled metal. Under the high temperature and high pressure environment of oil and gas transportation, especially when the medium contains corrosive components such as hydrogen sulfide and carbon dioxide, it is prone to corrosion and fatigue damage. Furthermore, the bellows has weak impact resistance; when the medium flow velocity fluctuates significantly or contains particulate impurities, the inner wall is easily eroded and worn, leading to a shortened service life and increased maintenance and replacement frequency and costs. Simultaneously, its compensation capacity is relatively small and its pressure resistance is weak, making it prone to cracking at bending points during long-term expansion and contraction, leading to medium leakage, especially in high-pressure oil and gas pipelines where the leakage risk is even higher.

[0005] Therefore, developing a thermal expansion compensation device that is suitable for complex working conditions of oil and gas pipelines, has good compensation effect, reliable sealing, and long service life is of great significance for improving the safety, economy and reliability of oil and gas pipeline systems. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a thermal expansion compensation device for oil and gas pipelines, which solves the problems mentioned in the background section.

[0007] To achieve the above objectives, this application provides the following technical solution: a thermal expansion compensation device for oil and gas pipelines, comprising: a telescopic pipe, a guide rod, and an inner core tube. The telescopic pipe consists of a corrugated pipe and end tubes welded to both ends of the corrugated pipe. Both ends of the telescopic pipe are welded with flanges for connection to flanges on the pipeline. The outer wall of the middle section of the end tubes is uniformly provided with lugs having through holes in the middle. Both ends of the guide rod are threaded with limiting nuts to restrict excessive displacement of the corrugated pipe after passing through the through holes in the lugs. The inner core tube is disposed inside the telescopic pipe, and both ends are sealed with compensation components. The compensation components are threaded into the inner core of the end tubes. The inner core tube is connected by a threaded connection; the inner wall of the end of the tube away from the corrugated tube has an internally threaded countersunk hole and an external stepped hole; both ends of the inner core tube have annular grooves along their side walls, and annular rubber rings filled with polyelectrolyte solution are set inside the annular grooves; the inner core tube and the corrugated tube form a double-layer isolation design; the compensation component includes a T-shaped guide tube with threads set inside the internally threaded countersunk hole; a compression spring and an annular wedge-shaped retaining ring are fitted on the outer wall of the T-shaped guide tube; one end of the compression spring abuts against the outer wall of the stepped part of the T-shaped guide tube, and the other end abuts against the outer wall of the annular wedge-shaped retaining ring; the end of the T-shaped guide tube facing the inner core tube is slidably set inside the annular groove.

[0008] According to an advantageous embodiment, the end of the T-shaped guide tube facing the inner core tube is provided with multiple concentric annular protrusions, and the end of the T-shaped guide tube facing the inner core tube is provided with a sealing gasket that cooperates with the annular protrusions. The sealing gasket is slidably disposed inside the annular groove.

[0009] According to an advantageous embodiment, the T-shaped guide tube has several evenly arranged annular grooves on both its inner and outer walls at the annular sink position, and a sealing ring is provided inside the annular groove.

[0010] According to an advantageous embodiment, the outer wedge surface of the annular wedge retainer abuts against the gap between the inner core tube and the end tube, and the inner wedge surface of the annular wedge retainer abuts against the gap between the inner core tube and the T-shaped guide tube.

[0011] According to an advantageous embodiment, wedge-shaped rings are threaded onto both ends of the inner core tube, and the outer wall of the wedge-shaped rings is fitted with several sealing rings that fit and seal against the inner wall of the T-shaped guide tube.

[0012] According to an advantageous embodiment, the compensation component further includes a mating sleeve threaded onto the outer wall of the internally threaded countersunk hole. A T-shaped rubber ring is provided at one end of the mating sleeve facing the T-shaped guide cylinder. A convex ring seat is also provided on the outer wall of the mating sleeve. The convex ring seat is located inside the outer stepped hole. A rubber gasket is also provided on the outer wall of the mating sleeve at the position where the convex ring seat abuts against the inner wall of the outer stepped hole.

[0013] According to an advantageous embodiment, the inner wall of the inner core tube is coated with a corrosion-resistant and rust-proof coating.

[0014] According to an advantageous embodiment, the polyelectrolyte solution filled within the annular rubber ring has thermal shrinkage and cold expansion characteristics.

[0015] Compared with the prior art, the thermal expansion compensation device for oil and gas pipelines provided in this embodiment of the invention has the following beneficial effects: 1. The invention uses a double-layer isolation design, so that the medium only flows through the inner core tube, whose inner wall is coated with a corrosion-resistant coating, while the corrugated pipe is located on the outer layer and does not directly contact the medium, thus fundamentally avoiding corrosion and erosion; at the same time, the medium flow path is optimized by the wedge-shaped ring sleeve, reducing turbulence and impurity deposition, further reducing the risk of wear of the inner core tube, increasing service life and reducing maintenance costs.

[0016] 2. This invention achieves a four-level sealing system through a labyrinthine annular protrusion, an annular wedge-shaped retaining ring, a sealing rubber ring, and a T-shaped rubber ring. It also incorporates an annular rubber ring filled with a polyelectrolyte solution to automatically adjust the air pressure within the annular settling tank, preventing negative or overpressure during thermal expansion and contraction. This ensures effective sealing and smooth media flow. Furthermore, the sealing rubber ring within the annular arc groove scrapes away impurities as it moves with the T-shaped guide tube, achieving an anti-jamming design and significantly improving displacement compensation under complex operating conditions.

[0017] 3. The present invention greatly increases the sliding space by setting annular grooves on both sides, thereby greatly increasing the compensation for displacement of the pipeline caused by temperature. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0019] Figure 2 This is a front-view sectional view of the present invention.

[0020] Figure 3 For the present invention Figure 2 A magnified view of section A in the image.

[0021] Figure 4 For the present invention Figure 2 A magnified view of section B in the image.

[0022] Figure 5 This is a three-dimensional structural diagram of the annular wedge-shaped retaining ring of the present invention.

[0023] The attached figures are labeled as follows: 1. Telescopic tube; 11. Bellows; 12. End tube; 13. Ear seat; 2. Guide rod; 21. Limiting nut; 3. Inner core tube; 4. Compensating component; 121. Internal thread countersunk hole; 122. External stepped hole; 31. Annular groove; 32. Annular rubber ring; 41. T-shaped guide tube; 42. Compression spring; 43. Annular wedge face retaining ring; 411. Annular protrusion; 412. Sealing gasket; 413. Annular arc groove; 414. Sealing rubber ring; 5. Wedge angle ring sleeve; 51. Sealing rubber ring; 44. Butt sleeve; 45. T-shaped rubber ring; 46. Convex ring seat; 47. Rubber gasket. Detailed Implementation

[0024] The following is in conjunction with the appendix Figure 1 - Appendix Figure 5 This application will now be described in further detail.

[0025] Please refer to the following: Figure 1 , Figure 2 and Figure 3 A thermal expansion compensation device for oil and gas pipelines includes: a telescopic pipe 1, a guide rod 2, and an inner core tube 3. The telescopic pipe 1 is composed of a corrugated pipe 11 and end pipes 12 welded to both ends of the corrugated pipe 11. Both ends of the telescopic pipe 1 are welded with flanges for connection to flanges on the pipeline. The outer wall of the middle part of the end pipe 12 is uniformly provided with lugs 13 with through holes in the middle. Both ends of the guide rod 2 are threaded through the through holes on the lugs 13 and are threaded with limiting nuts 21 for limiting excessive displacement of the corrugated pipe 11. The inner core tube 3 is disposed inside the telescopic pipe 1, and both ends of it are sealed and connected with compensation components 4. The compensation components 4 are threadedly connected to the inside of the end pipe 12. It should be noted that, specifically, a corrosion-resistant and rust-proof coating can be plated on the inner wall of the inner core tube 3 according to the acid and alkali properties of the circulating medium.

[0026] During actual installation and use, the flanges at both ends of this oil and gas pipeline thermal expansion compensation device are connected to the flanges at both ends of the pipeline, respectively. Then, according to the temperature of the medium being transported inside the pipeline and the temperature of the surrounding environment, the position of the limit nut 21 on the outer wall of the guide rod 2 is adjusted according to the temperature range specified. This limits the expansion and contraction displacement of the expansion tube 1 and the compensation component 4 according to the temperature range. When the pipeline expands and deforms due to temperature, the relative deformation of the expansion tube 1 and the compensation component 4 is used to cope with the lateral displacement of the pipeline after expansion, thereby preventing pipeline damage and cracking.

[0027] Please refer to the following: Figure 2 and Figure 4The inner wall of the end of the end tube 12 away from the corrugated pipe 11 is provided with an internally threaded countersunk hole 121 and an external stepped hole 122; both ends of the inner core tube 3 are provided with annular grooves 31 along their side walls, and annular rubber rings 32 filled with polyelectrolyte solution are provided inside the annular grooves 31; when the temperature rises, the molecular chains of the polyelectrolyte solution inside contract (volume shrinkage) due to increased thermal motion, and when the temperature drops, the molecular chains expand (volume expansion), thus exhibiting thermal contraction and cold expansion; the annular rubber rings 32 filled with polyelectrolyte solution can keep the internal air pressure balance of the annular grooves 31 in a sealed state, and avoid the compensation component 4 from being unable to contract due to the increased air pressure inside the annular grooves 31 caused by the expansion and contraction of the pipe.

[0028] Please refer to the following: Figure 2 , Figure 3 and Figure 5 The compensation component 4 includes a T-shaped guide tube 41 threaded inside the internal thread countersunk hole 121; a compression spring 42 and an annular wedge retainer 43 are sleeved on the outer wall of the T-shaped guide tube 41; one end of the compression spring 42 abuts against the outer wall of the step of the T-shaped guide tube 41, and the other end abuts against the outer wall of the annular wedge retainer 43; it should be noted that the elastic coefficient of the compression spring 42 is matched and set according to the thermal expansion corresponding to the working temperature range of the pipeline; the end of the T-shaped guide tube 41 facing the inner core tube 3 is slidably disposed inside the annular groove 31; while the T-shaped guide tube 41 slides laterally inside the annular groove 31, it can also maintain a seal, and the sliding space of the two annular grooves 31 greatly improves the compensation for the displacement of the pipeline caused by temperature.

[0029] During use, whether the pipeline extends or contracts, it will cause the T-shaped guide cylinders 41 in the compensation components 4 on both sides to move relative to each other. During the movement of the T-shaped guide cylinders 41, the compression springs 42 in a compressed state will move adaptively. The compression springs 42 push the outer wedge surface of the annular wedge ring 43 to abut against the gap between the inner core tube 3 and the end tube 12, and the inner wedge surface to abut against the gap between the inner core tube 3 and the T-shaped guide cylinders 41; thus maintaining the internal sealing and preventing leakage of the circulating oil and gas medium.

[0030] By setting the compensation component 4, the impurities in the medium can be prevented from scouring the inner wall of the bellows 11 when it is transporting oil and gas. The inner core tube 3, in conjunction with the compensation component 4, can transport the medium through the straight inner core tube 3, thus extending the service life of the bellows 11 when transporting the medium. Furthermore, the inner core tube 3 and the compensation component 4 work together to achieve a double-layer air pressure seal for the bellows 11, improving the pressure-bearing capacity of the bellows 11. Because the bellows 11 and the inner core tube 3 are in a sealed state, the internal air pressure is stable as a whole, which can effectively reduce cracking at the bending point during the expansion and contraction of the bellows 11, while preventing medium leakage.

[0031] Please refer to the following: Figure 3 The T-shaped guide tube 41 is provided with multiple concentric annular protrusions 411 at one end facing the inner core tube 3, and a sealing gasket 412 that cooperates with the annular protrusions 411 is provided at the other end facing the inner core tube 3. The sealing gasket 412 is slidably disposed inside the annular groove 31. The combination of multiple concentric annular protrusions 411 and sealing gasket 412 can achieve multi-layer labyrinth-style dust prevention and sealing, effectively preventing leakage of oil and gas media and dust and other impurities from entering the interior of the annular groove 31 and causing the T-shaped guide tube 41 to jam when moving along the annular groove 31.

[0032] Please refer to the following: Figure 3 The T-shaped guide tube 41 has several evenly arranged annular arc grooves 413 on both its inner and outer walls at the position of the annular trough 31. A sealing ring 414 is provided inside the annular arc groove 413. The sealing ring 414 can seal the oil and gas medium transported in the pipeline to prevent leakage, while preventing impurities and particles from entering the interior of the annular trough 31 and causing the T-shaped guide tube 41 to get stuck when it moves along the annular trough 31.

[0033] Please refer to the following: Figure 3 The inner core tube 3 has wedge-shaped rings 5 ​​threaded at both ends, and the outer wall of the wedge-shaped rings 5 ​​is fitted with several sealing rings 51 that fit and seal against the inner wall of the T-shaped guide tube 41. The sealing rings 51, through a labyrinth-type dustproof seal, can prevent impurities in the transported oil and gas medium from entering the annular settling groove 31, and avoid jamming when the T-shaped guide tube 41 moves along the annular settling groove 31; at the same time, it can also prevent leakage. The wedge-shaped rings 5 ​​can also keep the process of the medium flowing from the pipeline into the inner core tube 3 smooth, and prevent impurities in the oil and gas medium from causing the medium to flow through the steps between the inner core tube 3 and the T-shaped guide tube 41, which would cause the medium to flow through the steps, resulting in excessive pressure and leakage; and it can also prevent impurities in the medium from accumulating at the steps.

[0034] Please refer to the following: Figure 2The compensation component 4 further includes a mating sleeve 44 threaded onto the outer wall of the internally threaded countersunk hole 121. A T-shaped rubber ring 45 is provided at one end of the mating sleeve 44 facing the T-shaped guide cylinder 41. A convex ring seat 46 is also provided on the outer wall of the mating sleeve 44, located inside the outer stepped hole 122. A rubber gasket 47 is also fitted on the outer wall of the mating sleeve 44 at the position where the convex ring seat 46 abuts against the inner wall of the outer stepped hole 122. During installation, the T-shaped rubber ring 45 is placed inside the internally threaded countersunk hole 121, and then the rubber gasket 47 is fitted on the outer wall of the mating sleeve 44. The mating sleeve 44 is then screwed on, and the T-shaped rubber ring 45 and the rubber gasket 47 are squeezed by the mating sleeve 44, thereby providing multi-stage sealing at the connection between the T-shaped guide cylinder 41 and the end pipe 12 to prevent leakage of the internally flowing oil and gas medium. At the same time, one end of the T-shaped rubber ring 45 fits more tightly against the side wall of the T-shaped guide cylinder 41, ensuring a sufficient sealing effect.

[0035] This invention utilizes a wedge-shaped ring sleeve 5 to reduce the scouring pressure of the medium at the stepped joint. It works in conjunction with a sealing ring 51, a sealing rubber ring 414, a sealing gasket 412, and an annular wedge-shaped retaining ring 43 to achieve a four-level seal, effectively preventing medium leakage into the gap between the bellows 11 and the inner core tube 3, thereby ensuring the expansion and contraction effect of the bellows 11 and improving its service life.

[0036] Specifically, after connecting this device to the pipeline, when oil and gas media flow inside, the pipeline will undergo lateral displacement due to the influence of temperature. At this time, the lateral displacement of the pipeline will push the T-shaped guide cylinder 41 to expand and contract inside the annular trough 31. Due to the multi-stage sealing, it can be ensured that no leakage will occur during its expansion and contraction. At the same time, the annular rubber ring 32 can keep the internal air pressure balance of the annular trough 31 in a sealed state, and prevent the compensation component 4 from failing to expand and contract due to the expansion and contraction of the T-shaped guide cylinder 41 inside the annular trough 31 causing an increase or decrease in the air pressure inside the annular trough 31.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the terms "first," "second," "number one," and "number two" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," "number one," or "number two" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A thermal expansion compensation device for oil and gas pipelines, characterized in that, include: The expansion joint consists of a corrugated pipe and end pipes welded to both ends of the corrugated pipe. Both ends of the expansion joint are welded with flanges for connection to flanges on the pipeline. The outer wall of the middle part of the end pipe is evenly provided with lugs with through holes in the middle. The guide rod has through holes on the lugs at both ends and is threaded with limit nuts to limit excessive displacement of the bellows; The inner core tube is located inside the telescopic tube, and both ends of it are sealed with compensation components, which are threadedly connected to the inside of the end tube. The inner wall of the end tube away from the bellows is provided with an internally threaded countersunk hole and an external stepped hole. Both ends of the inner core tube are provided with annular grooves along their sidewalls, and annular rubber rings filled with polyelectrolyte solution are provided inside the annular grooves; the inner core tube and the corrugated tube form a double-layer isolation design. The compensation component includes a T-shaped guide tube with threads set inside the internal thread countersunk hole; a compression spring and an annular wedge retainer are sleeved on the outer wall of the T-shaped guide tube; one end of the compression spring abuts against the outer wall of the stepped part of the T-shaped guide tube, and the other end abuts against the outer wall of the annular wedge retainer; the end of the T-shaped guide tube facing the inner core tube is slidably disposed inside the annular countersunk groove.

2. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, The T-shaped guide tube has multiple concentric annular protrusions at one end facing the inner core tube, and a sealing gasket that matches the annular protrusions is provided at the same end facing the inner core tube. The sealing gasket is slidably disposed inside the annular groove.

3. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, The T-shaped guide tube has several evenly arranged annular grooves on both its inner and outer walls at the annular sink position, and a sealing ring is installed inside the annular groove.

4. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, The outer wedge surface of the annular wedge retainer abuts against the gap between the inner core tube and the end tube, and the inner wedge surface of the annular wedge retainer abuts against the gap between the inner core tube and the T-shaped guide tube.

5. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, Both ends of the inner core tube are respectively threaded with wedge-shaped ring sleeves, and the outer wall of the wedge-shaped ring sleeves is fitted with several sealing rings that fit and seal against the inner wall of the T-shaped guide tube.

6. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, The compensation component further includes a mating sleeve with threads set on the outer wall of the internal thread countersunk hole. A T-shaped rubber ring is provided at one end of the mating sleeve facing the T-shaped guide cylinder. The outer wall of the mating sleeve is also provided with a convex ring seat, which is located inside the outer stepped hole. A rubber gasket is also provided on the outer wall of the mating sleeve at the position where the convex ring seat abuts against the inner wall of the outer stepped hole.

7. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, The inner wall of the inner core tube is coated with a corrosion-resistant and rust-proof coating.

8. The thermal expansion compensation device for oil and gas pipelines according to claim 1, characterized in that, The polyelectrolyte solution filled inside the annular rubber ring has thermal shrinkage and cold expansion characteristics.

Images