Mechanical sealing structure suitable for gas-liquid mixed-phase medium

Abstract

The invention discloses a mechanical sealing structure suitable for a gas-liquid mixed-phase medium, which is arranged in a sealing cavity of a multiphase multiphase pump and comprises a driving shaft, a shaft sleeve sleeved on the driving shaft, a movable ring seat and a sealing movable ring, a plurality of mixing blades and a rotating sleeve are arranged on the outer wall of the movable ring seat in the circumferential direction, and the rotating sleeve is sleeved on the shaft sleeve. An inner mixed flow channel is formed between the inner wall of the rotating sleeve and the outer wall of the movable ring seat, and an outer mixed flow channel is formed between the outer wall of the rotating sleeve and the inner wall of the sealing cavity; and a plurality of turbulent flow holes for communicating the outer mixed flow channel with the inner mixed flow channel are formed in the wall of the rotating sleeve. After primary crushing of the mixing blades and multiple and high-strength mixing inside and outside the turbulent flow hole channels, gas-liquid two-phase media are greatly homogenized to form a bubble / liquid drop two-phase mixture which is dispersed more finely and distributed more uniformly, and the mixture is continuously conveyed to a sealing end face area formed by the movable ring and the static ring, so that the sealing effect of the gas-liquid two-phase media is improved. And a layer of continuous and stable fluid film with certain bearing capacity is formed between the sealing end surfaces.

Description

Technical Field

[0001] This invention relates to the field of mechanical seal technology, specifically to a mechanical seal structure for preventing leakage of gas-liquid mixed media (such as oil-gas-water mixtures) in gas-liquid two-phase conveying equipment such as multiphase mixed-phase pumps. Background Technology

[0002] As a core piece of equipment in oil and gas extraction and transportation, the sealing device of the gas-liquid mixed-transport multiphase pump plays a crucial role in ensuring the safe operation of the equipment. This device prevents gas-liquid leakage, maintains stable internal pump pressure, and blocks the intrusion of external impurities, ensuring efficient multiphase media transport while effectively suppressing gas-liquid cross-contamination, thus avoiding cavitation and wear problems and guaranteeing long-term safe operation of the equipment and the stability and reliability of the entire transportation system.

[0003] Mechanical seals are widely used in rotating equipment such as pumps and compressors, as well as in critical fields such as gas-liquid multiphase pumps, due to their stable operation, low leakage rate, and long service life. They form a sealing surface through the tight fit of the dynamic and static ring end faces, effectively preventing leakage of the medium (liquid or gas) and blocking the intrusion of external impurities, while extending equipment life by reducing frictional losses.

[0004] In equipment such as multiphase pumps, the transported gas-liquid mixed media (such as gaseous crude oil, oil-gas-water mixtures, etc.) have complex physical properties. When traditional mechanical seals are applied to such media, the core challenge is the difficulty in forming a stable and uniform lubricating film between the sealing surfaces. This is because the gas and liquid phases easily separate, leading to insufficient lubrication of the sealing surfaces (dry friction) or fluctuations in liquid film pressure (cavitation, flash evaporation). This results in increased wear on the sealing surfaces, increased leakage, and severe heat generation, ultimately leading to decreased sealing performance and shortened lifespan.

[0005] In summary, there is an urgent need for a mechanical seal structure that can effectively improve the uniformity and flow stability of gas-liquid mixed media in the sealing area, thereby ensuring the stability of the lubricating film on the sealing end face. Summary of the Invention

[0006] To address the technical shortcomings of existing technologies, such as unstable lubrication film on mechanical seal end face, poor sealing performance, and short lifespan caused by gas-liquid mixed media, this invention provides a mechanical seal structure that can actively mix and homogenize gas-liquid two-phase media, promoting the formation of a stable lubrication film.

[0007] The technical solution adopted in this invention is: A mechanical seal structure suitable for gas-liquid mixed media is installed in the sealing cavity (4) of a multiphase mixed-transfer pump, including a drive shaft (1), a bushing (2) fitted on the drive shaft (1), a rotating ring seat (24), and a sealing rotating ring (8). The bushing (2) is fitted on the drive shaft (1), the rotating ring seat (24) is fitted on the bushing (2), and the sealing rotating ring (8) is fitted on the rotating ring seat (24). The stationary ring (7) is disposed on the end face side of the sealing rotating ring (8) and fixedly connected to the sealing end cover (6). The sealing end cover (6) is fixed to the sealing cavity (4) by a first bolt (5). Its features are: The outer wall of the moving ring seat (24) is provided with a plurality of mixing blades (19) and a rotating sleeve (22). An inner mixing channel (18) is formed between the inner wall of the rotating sleeve (22) and the outer wall of the moving ring seat (24), and an outer mixing channel (21) is formed between the outer wall of the rotating sleeve (22) and the inner wall of the sealing cavity (4). A plurality of turbulence holes (20) are provided on the cylinder wall of the rotating sleeve (22) for connecting the outer mixing channel (21) and the inner mixing channel (18).

[0008] Furthermore, a flow guide ring (17) is installed at the medium inlet end of the internal mixing channel (18), and multiple flow guide channels (25) are arranged circumferentially on the surface of the flow guide ring (17).

[0009] Furthermore, the inlet section of the flow ring (17) is provided with 8 to 12 flow channels (25), the profile of the flow channels (25) is a spiral, and the spiral direction is consistent with the rotation direction of the drive shaft (1), so as to draw the gas-liquid mixed medium into the inner mixing channel (18).

[0010] Furthermore, the hybrid blade (19) is a rectangular or trapezoidal structure, welded to the outer periphery of the moving ring seat (24), and is used for powerful shearing and conveying of the medium when rotating with the main shaft.

[0011] Furthermore, the rotating sleeve (22) is welded to the outer periphery of the moving ring seat (24), and together with the mixing blade (19), they form an integral rotating assembly.

[0012] Furthermore, the rotating sleeve (22) is provided with a plurality of turbulence holes (20) in both the circumferential and axial directions. The plurality of turbulence holes (20) are arranged in an alternating manner. The diameter of the turbulence holes (20) is 4~5mm and the spacing between adjacent turbulence holes (20) is 7~8mm.

[0013] The technical concept of this invention is as follows: After initial crushing by the mixing blades and multiple, high-intensity mixing actions inside and outside the turbulence orifice channel, the gas-liquid two-phase medium is greatly homogenized, forming a more finely dispersed and uniformly distributed bubble / droplet two-phase mixture. This homogenized mixture is continuously transported to the sealing end face area formed by the moving and stationary rings. The uniform mixture can more effectively form a continuous, stable fluid film with a certain load-bearing capacity between the sealing end faces. This liquid film effectively isolates the direct contact between the moving and stationary rings, converting friction into viscous shear within the fluid film, greatly reducing frictional wear and heat generation. The stable fluid film pressure also reduces the risk of liquid film flash rupture (cavitation) caused by gas phase aggregation, improving the reliability, sealing performance, and service life of the seal under harsh gas-liquid mixed-phase conditions.

[0014] The innovation of this invention is that by rotating the moving ring seat, the mixing blades actively stir, shear and mix the gas-liquid mixed medium near the sealing cavity, forming a continuous, stable fluid film with a certain load-bearing capacity between the sealing end faces.

[0015] Compared with the prior art, the beneficial effects of the present invention are reflected in: 1. This invention utilizes a mixing blade, sleeve, and turbulence-inducing hole structure driven by a moving ring seat to actively and powerfully perform multi-stage mixing and homogenization of the gas-liquid mixed-phase medium within the sealing cavity. This forms a homogenized gas-liquid two-phase lubricating medium on the outer diameter side of the sealing end face, effectively solving the core problem of unstable end-face lubricating film caused by the heterogeneity of the gas-liquid two-phase sealing medium in traditional seals. 2. The present invention uses a stable lubricating film to reduce friction, wear and heat generation on the sealing end face, which can significantly improve the working stability, reliability, sealing performance and service life of mechanical seals under harsh gas-liquid mixed phase conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the moving ring seat and its internal structure in this invention.

[0018] Figure 3 This is the drainage ring in this invention.

[0019] Figure 4 This is a left view of the moving ring seat in this invention.

[0020] Figure 5 This is a top view of the moving ring seat in this invention.

[0021] Explanation of reference numerals in the attached figures: 1. Drive shaft; 2. Bushing; 3. Set screw; 4. Sealing cavity; 5. First bolt; 6. Sealing end cap; 7. Stationary ring; 8. Rotating ring; 9. Anti-rotation pin; 10. First O-ring; 11. First transmission pin; 12. Second transmission pin; 13. Second O-ring; 14. Spring; 15. Third O-ring; 16. Second bolt; 17. Drainage ring; 18. Inner mixing channel; 19. Mixing blade; 20. Turbulence hole; 21. Outer mixing channel; 22. Rotating sleeve; 23. Fourth O-ring; 24. Rotating ring seat; 25. Spiral inlet. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0025] refer to Figures 1 to 5 The present invention provides a mechanical seal structure suitable for gas-liquid mixed media, which is installed in the sealing cavity 4 of a multiphase mixed pump. It includes a drive shaft 1, a bushing 2 fitted on the drive shaft 1, a rotating ring seat 24, and a sealing rotating ring 8. The bushing 2 is fitted on the drive shaft 1, the rotating ring seat 24 is fitted on the bushing 2, and the sealing rotating ring 8 is fitted on the rotating ring seat 24. The stationary ring 7 is disposed on the end face side of the sealing rotating ring 8 and is fixedly connected to the sealing end cover 6. The sealing end cover 6 is fixed to the sealing cavity 4 by a first bolt 5. The outer wall of the rotating ring seat 24 is provided with a plurality of mixing blades 19 and a rotating sleeve 22. An inner mixing channel 18 is formed between the inner wall of the rotating sleeve 22 and the outer wall of the rotating ring seat 24. An outer mixing channel 21 is formed between the outer wall of the rotating sleeve 22 and the inner wall of the sealing cavity (4). A plurality of turbulence holes 20 are opened on the cylinder wall of the rotating sleeve 22 for connecting the outer mixing channel 21 and the inner mixing channel 18.

[0026] Specifically, the stationary ring 7 is located on the end face of the sealing rotating ring 8 and is fixed by an anti-rotation pin 9 on the sealing end cover 6 to prevent the stationary ring 7 from rotating. The sealing end cover 6 is fixed to the sealing cavity 4 of the pump by a first bolt 5.

[0027] Specifically, the bushing 2 is fitted onto the drive shaft 1 by a set screw 3, and the drive shaft drives the bushing 2 to rotate.

[0028] In one embodiment, a flow guide ring 17 is installed at the medium inlet end of the internal mixing channel 18, and a plurality of flow guide channels 25 are arranged circumferentially on the surface of the flow guide ring 17.

[0029] In one embodiment, the inlet section of the drainage ring 17 is provided with 8 to 12 flow channels 25, the profile of the flow channels 25 is a spiral, and the spiral direction is consistent with the rotation direction of the drive shaft 1, so as to draw the gas-liquid mixed medium into the inner mixing channel 18.

[0030] In one embodiment, the hybrid blade 19 is a rectangular or trapezoidal structure, welded to the outer periphery of the moving ring seat 24, for powerful shearing and conveying of the medium when rotating with the main shaft.

[0031] Specifically, when the moving ring seat 24 rotates, the mixing blades 19 on its outer wall also rotate at high speed. The mixing blades intensely stir, shear, and impact the gas-liquid mixed medium entering its working area, breaking up large bubble clusters and promoting preliminary mixing of the gas and liquid phases. The rotating sleeve 22 rotates together with the moving ring seat 24. Under the action of centrifugal force, the medium is thrown towards the outer wall of the rotating sleeve and enters the outer mixing channel 21.

[0032] In one embodiment, the rotating sleeve 22 is welded to the outer periphery of the moving ring seat 24, and together with the mixing blade 19, forms an integral rotating assembly.

[0033] In one embodiment, the rotating sleeve 22 has a plurality of turbulence holes 20 in both the circumferential and axial directions. The plurality of turbulence holes 20 are arranged in an alternating manner. The diameter of the turbulence holes 20 is 4-5 mm and the spacing between adjacent turbulence holes 20 is 7-8 mm.

[0034] In one embodiment, one end of the bushing is fixedly mounted on the drive shaft 1 by a set screw 3.

[0035] In one embodiment, the sealing ring 8 and the ring seat 24 are driven to rotate by a first transmission pin 11; the ring seat 24 and the bushing 2 are driven to rotate by a second transmission pin 12.

[0036] In one embodiment, the moving ring seat 24 is circumferentially arranged with multiple sets of springs 14, and the loading force of the springs 14 enables the end face of the sealing moving ring 8 to be tightly fitted with the end face of the stationary ring 7 to form the main sealing end face.

[0037] Specifically, a first O-ring 10, a second O-ring 13, a third O-ring 15, and a fourth O-ring 23 are respectively provided between the sealing end cover and the stationary ring, between the drive shaft and the rotating ring seat, between the rotating ring seat and the bushing, and between the rotating ring seat and the rotating ring to provide necessary auxiliary static seals.

[0038] The working principle of this invention is as follows: During flow, the medium in the inner mixing channel 18 is continuously injected laterally into the inner mixing channel 18 through the circumferential turbulence holes 20 under the action of pressure difference and rotational shear. The axial turbulence holes 20 allow some of the medium to flow under the axial pressure gradient, generating turbulence. These turbulence holes disrupt the stable flow of the fluid, generating strong turbulence, vortices, and secondary flows. The medium in the inner mixing channel 18 and the medium injected into the outer mixing channel 21 undergo violent collisions, shearing, and mixing with each other near the turbulence holes 20 and within the inner mixing channel 18.

[0039] After initial crushing by the mixing blades and multiple, high-intensity mixing processes inside and outside the turbulence orifice channels, the gas-liquid two-phase medium is greatly homogenized, forming a finer, more uniformly distributed bubble / droplet two-phase mixture. This homogenized mixture is continuously transported to the sealing end face area formed by the moving and stationary rings. The homogeneous mixture can more effectively form a continuous, stable, and load-bearing fluid film between the sealing end faces. This liquid film effectively isolates the direct contact between the moving and stationary rings, converting friction into viscous shear within the fluid film, greatly reducing frictional wear and heat generation. The stable fluid film pressure also reduces the risk of liquid film flash rupture (cavitation) caused by gas phase aggregation, improving the reliability, sealing performance, and service life of the seal under harsh gas-liquid mixed-phase conditions.

[0040] The core of this invention lies in driving the integrated mixing structure by rotating the moving ring seat to actively stir, shear and mix the gas-liquid mixed medium near the sealing cavity, so as to homogenize it and form a stable liquid film between the sealing end faces.

[0041] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A mechanical seal structure suitable for gas-liquid mixed phase medium, installed in a seal cavity (4) of a multiphase mixed transport pump, comprising a driving shaft (1), a shaft sleeve (2) sleeved on the driving shaft (1), a dynamic ring seat (24) and a sealing dynamic ring (8), the shaft sleeve (2) is sleeved on the driving shaft (1), the dynamic ring seat (24) is sleeved on the shaft sleeve (2), and the sealing dynamic ring (8) is sleeved on the dynamic ring seat (24); the static ring (7) is arranged on the end surface side of the sealing dynamic ring (8) and fixedly connected with a sealing end cover (6), and the sealing end cover (6) is fixed on the seal cavity (4) through a first bolt (5); characterized in that: A plurality of mixing blades (19) and a rotating sleeve (22) are arranged on the outer wall of the dynamic ring seat (24) in the circumferential direction, an inner mixing flow channel (18) is formed between the inner wall of the rotating sleeve (22) and the outer wall of the dynamic ring seat (24), and an outer mixing flow channel (21) is formed between the outer wall of the rotating sleeve (22) and the inner wall of the seal cavity (4); a plurality of turbulence holes (20) for connecting the outer mixing flow channel (21) and the inner mixing flow channel (18) are arranged on the cylinder wall of the rotating sleeve (22).

2. The gas-liquid-miscible medium mechanical seal structure according to claim 1, characterized by, A flow guide ring (17) is arranged at the medium inlet end of the inner mixing flow channel (18), and a plurality of guide flow channels (25) are arranged on the ring surface of the flow guide ring (17) in the circumferential direction.

3. The gas-liquid-miscible medium mechanical seal structure according to claim 2, characterized by, 8-12 guide flow channels (25) are arranged at the inlet section of the flow guide ring (17), the guide flow channels (25) are in the form of helical lines, the rotation direction of the helical lines is consistent with the rotation direction of the driving shaft (1), and the gas-liquid mixed phase medium is sucked into the inner mixing flow channel (18).

4. The gas-liquid-miscible medium mechanical seal structure according to claim 1, wherein The mixing blades (19) are in one of rectangular and trapezoidal structures, are welded on the outer periphery of the dynamic ring seat (24), and are used for strongly shearing and transporting the medium when the main shaft rotates.

5. The gas-liquid-miscible medium mechanical seal structure according to claim 4, characterized by, The rotating sleeve (22) is welded on the outer periphery of the dynamic ring seat (24) and constitutes a whole rotating assembly together with the mixing blades (19).

6. The gas-liquid-miscible medium mechanical seal structure according to claim 1, wherein A plurality of turbulence holes (20) are arranged on the rotating sleeve (22) in the circumferential and axial directions, the plurality of turbulence holes (20) are arranged in a staggered manner, the diameter of the turbulence hole (20) is 4-5 mm, and the spacing between adjacent turbulence holes (20) is 7-8 mm.

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