A rotary joint device for ultra-low temperature unloading transmission system

Abstract

The present invention relates to a rotary joint device of an ultra-low temperature unloading transmission system, comprising an annular cavity wall and a regulating component, wherein a low temperature fluid channel is formed in the annular cavity wall, the regulating component comprises a flow guide and a flow regulating mechanism, the flow guide comprises a direct flow section, a first flow expansion section and a second flow expansion section, the first flow expansion section and the second flow expansion section are both truncated cone structures, and the diameter of the bottom surface of the second flow expansion section is greater than the diameter of the bottom surface of the first flow expansion section, the flow regulating mechanism comprises an outer bracket, an inner bracket, a positioning nut and a bolt, the outer bracket is fixedly connected to the annular cavity wall, the inner bracket is fixedly connected to the flow guide, the bolt is fixedly connected to the inner bracket and is slidably connected to the outer bracket, and a positioning nut and a bolt are arranged on the upper and lower parts of the outer bracket for rotational connection. The present invention can ensure the internal flow stability of the rotary joint device through the regulating component, and avoid the backflow phenomenon at the same time, and avoid the malfunction of the rotary joint due to the freezing of the flow-through parts due to the temperature difference between the inside and the outside through the arrangement of the vacuum insulation layer and the inert gas purge.

Description

Technical Field

[0001] The invention relates to the technical field of low-temperature medium transportation, and in particular to a rotary joint device of an ultra-low-temperature unloading transmission system. Background Art

[0002] LNG Floating Production Storage and Offloading Unit (FLNG) is a floating production unit used for offshore natural gas field development. It is positioned at sea through a mooring system and has the functions of mining, processing, liquefying, storing and loading and unloading natural gas. It is used in conjunction with liquefied natural gas (LNG) ships to achieve offshore natural gas field mining and natural gas transportation. The use of FLNG for offshore gas field development has ended the single mode of offshore gas fields being able to only be transported to shore by pipeline, saving transportation costs and not occupying land space. In addition, FLNG can also be used for a second time after the gas field is mined and placed in other natural gas fields, with high economic performance.

[0003] LNG unloading arm is a rigid articulated pipeline system installed on the dock or FLNG for LNG unloading. The main structure includes process pipelines such as swivel joints, outer arms, inner arms, base risers, and swivel joints connecting the inner arms and base risers, as well as their supporting structures and accessories. The large LNG unloading arm stands at the front end of the LNG receiving station dock area. As the key core equipment connecting the LNG ship with the onshore pipeline and storage facilities, it is the "throat" of the entire receiving station. When the LNG transport ship arrives at the dedicated dock of the receiving station, the LNG is sent into the storage tank of the receiving station through the liquid unloading arm and unloading pipeline using the cryogenic pump on the ship. At the same time, the boil-off gas (BOG) in the storage tank is returned to the LNG transport ship through the return gas pipeline and the gaseous return gas arm. During the operation of the LNG unloading arm, the end of the unloading arm is guided to interconnect with the receiving end of the LNG ship through the traction line to ensure accurate docking under relative motion, and the hydraulic system of the unloading arm is controlled so that it can withstand the speed and acceleration caused by the movement of the hull.

[0004] Existing mooring technology and traditional rigid unloading arms are difficult to effectively solve the problem of differentiated movement between the FLNG floating platform and the carrier of the transport ship. Therefore, a specially designed cryogenic external unloading system is needed to meet the stringent requirements of low temperature and swaying conditions. The cryogenic hose delivery system has obvious comprehensive advantages in weight, flexibility, corrosion resistance, and thermal insulation. When FLNG is transported externally, an effective way is to use tandem mooring, that is, to connect to the LNG transport ship through a mooring cable and use a cryogenic hose to unload LNG. The cryogenic hose is required to withstand ultra-low temperatures and overcome the influence of relative movement between the FLNG and the LNG transport ship.

[0005] In addition, the liquid hydrogen shipping test has been successfully implemented, providing a more economical and safe way for the liquid hydrogen industry chain, which has positive significance for the promotion and use of hydrogen energy on a global scale and has strong development potential in the future. Liquid hydrogen has the characteristics of ultra-low temperature, volatility, flammability and explosion. The loading and unloading and transportation of liquid hydrogen from ship to shore is difficult, with high safety requirements and many technical barriers. The liquid hydrogen ship-to-shore loading and unloading system has harsh operating conditions, demanding motion accuracy, and complex coordination of electromechanical systems. It must have functions such as rapid docking, emergency detachment, and automatic shutdown, and must also withstand the long-term ultra-low temperature test of -253°C and automatically adapt to the influence of tidal drop.

[0006] In summary, the key technologies of ultra-low temperature fluid transportation systems such as LNG rigid unloading arms, LNG cryogenic hose transmission systems, and liquid hydrogen ship-to-shore loading and unloading systems all involve many links such as cryogenic material selection, molding and manufacturing, sealing, and test verification. Material selection and structural design are difficult, processing and manufacturing and performance testing are difficult, ultra-low temperature sealing, connection and leakage monitoring are difficult, and the entire cryogenic transportation system has a complex structure and high safety requirements. Among them, the rotary joint is a key component, and its performance directly affects the safe and stable operation of the ultra-low temperature fluid transportation system. As a key structural component for the flow of cryogenic media and providing steering, the rotary joint is required to prevent leakage of cryogenic media, withstand high-intensity loads and pressures, and have low friction losses during rotation under ultra-low temperature dynamic conditions.

[0007] At present, during the operation of the rotary joint device used in the prior art, the vibration generated when the low-temperature fluid flows through the rotary joint is large, resulting in large fatigue stress in the cryogenic transportation system, affecting the service life and stable operation. At the same time, during the operation of the cryogenic transportation system, it was found that when LNG or liquid hydrogen flows through the rotary joint, as well as during the transportation of natural gas or hydrogen in the gas phase, the flow state parameters cannot be optimized and matched due to the unstable flow of the low-temperature fluid inside the existing rotary joint. At the same time, there is also an unfavorable phenomenon of "backflow" during the flow process, which affects the stable operation of the cryogenic transportation system. The industry urgently needs to solve this key technical problem. In addition, during the operation of the rotary joint device in the prior art, there are no corresponding insulation and cold protection measures. Due to the large temperature difference between the internal and external flow components in the ultra-low temperature working environment, the phenomenon of external condensation and freezing of the rotary joint is prominent, and external icing often occurs, resulting in mechanical failure of the rotary joint components, seriously affecting the safe and stable operation of the cryogenic transportation system. Summary of the invention

[0008] The object of the present invention is to provide a rotary joint device for an ultra-low temperature unloading transmission system to solve the above-mentioned shortcomings of the rotary joint device in the prior art.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides a rotary joint device for an ultra-low temperature unloading transmission system, comprising an annular cavity wall and a regulating component, wherein a low temperature fluid channel flowing from top to bottom is formed in the annular cavity wall, and the regulating component is arranged in the low temperature fluid channel, comprising a flow guide and a flow regulating mechanism;

[0011] The flow guide comprises a direct flow section, a first flow expansion section and a second flow expansion section which are integrally formed from top to bottom, the direct flow section is a cylindrical structure, the first flow expansion section and the second flow expansion section are both truncated cone structures, and the diameter of the bottom surface of the second flow expansion section is greater than the diameter of the bottom surface of the first flow expansion section, wherein the direct flow section and the annular cavity wall are arranged with a central axis, and a flow passage is formed between the outer wall of the flow guide and the inner wall of the annular cavity wall;

[0012] The flow control mechanism includes an outer bracket, an inner bracket, a positioning nut and a bolt. The outer bracket is horizontally arranged in the low-temperature fluid channel and fixedly connected to the inner wall of the annular cavity wall. The inner bracket is horizontally arranged in the flow guide and fixedly connected to the flow guide. The bolt is vertically fixed to the inner bracket and connected to the outer bracket by moving up and down. The positioning nut is threadedly connected to the bolt, and one positioning nut is respectively arranged above and below the outer bracket.

[0013] Furthermore, the interior of the flow guide is a hollow structure, a pressure balance hole is provided on the top surface of the direct flow section, and the bottom surface of the second flow expansion section is open.

[0014] Furthermore, the internal angle range of the first expansion section is 65°-75°, and the internal angle range of the second expansion section is 85°-95°.

[0015] Furthermore, the inner wall of the annular cavity wall located at the first expansion section and the second expansion section bulges inward to form an annular inner convex portion, the upper surface of the inner convex portion is a curved surface structure and constitutes an upper arc segment, an annular flow guide area is formed between the upper arc segment and the outer walls of the first expansion section and the second expansion section, the lower surface of the inner convex portion is a curved surface structure and constitutes a lower arc segment, and an annular flow channel area is formed between the lower arc segment and the outer wall of the second expansion section.

[0016] Furthermore, the annular cavity wall includes an upper cavity wall and a lower cavity wall, the inner wall of the bottom end of the upper cavity wall bulges inwardly and constitutes an upper arc segment of the inner convex portion, the inner wall of the top end of the lower cavity wall bulges inwardly and constitutes a lower arc segment of the inner convex portion, a sealing assembly is provided between the upper arc segment and the lower arc segment, the sealing assembly includes a sealing ring and a compression spring, an annular sealing groove is provided on the bottom end surface of the upper arc segment, an annular receiving groove is provided on the inner bottom surface of the sealing groove, the sealing ring is fitted in the sealing groove, and a plurality of compression springs are arranged in the receiving groove along the circumferential direction, wherein at least one group of the sealing assembly is arranged from the inside to the outside of the annular cavity wall, and the inner diameters of the plurality of sealing rings increase successively from the inside to the outside of the annular cavity wall.

[0017] Furthermore, an annular bearing is sleeved on the outer side of the annular cavity wall, an upper flange is fixedly connected above the annular bearing, the top of the upper flange is interconnected with the upper cavity wall, a lower flange is fixedly connected below the annular bearing, the bottom end of the lower flange is interconnected with the lower cavity wall, and the inner wall of the upper flange, the inner wall of the lower flange and the inner wall of the annular bearing together form a vacuum insulation layer with the outer cavity wall of the annular cavity wall, a vertically arranged vibration-damping spring is provided in the vacuum insulation layer, one side of the vibration-damping spring is fixedly connected to the outer cavity wall of the annular cavity wall, and the other side of the vibration-damping spring is fixedly connected to the inner wall of the annular bearing.

[0018] Further, the annular bearing includes a bearing inner ring, a bearing outer ring and a ball bearing, the bearing outer ring is fixedly connected to the lower flange, the bearing inner ring is fixedly connected to the upper flange, the bearing inner ring is arranged on the inner side of the bearing outer ring, and the outer wall of the bearing inner ring is arranged tightly against the inner wall of the bearing outer ring, a first semicircular annular groove is opened on the outer wall of the bearing inner ring, and a second semicircular annular groove corresponding to the first semicircular annular groove is opened on the inner wall of the bearing outer ring, the first semicircular annular groove and the second semicircular annular groove together constitute a clamping groove, the ball bearing is assembled in the clamping groove, and a gasket is provided between two adjacent balls in the ball bearing.

[0019] Furthermore, the outer ring of the bearing is fixedly connected to the lower flange by bolts, an outer ring sealing ring is embedded between the contact interface between the lower flange and the outer ring of the bearing, and a lower sealing ring is embedded between the contact interface between the lower flange and the inner ring of the bearing, the inner ring of the bearing is fixedly connected to the upper flange by bolts, an inner ring sealing ring is embedded between the contact interface between the upper flange and the inner ring of the bearing, and an upper sealing ring is embedded between the contact interface between the upper flange and the outer ring of the bearing.

[0020] Furthermore, an annular inner ring inert gas purge pipeline is provided in the inner ring of the bearing, an upper ferrule joint is fixedly connected to the upper flange, and the upper ferrule joint connects the inner ring inert gas purge pipeline with the external inert dry gas pipeline; an annular outer ring inert gas purge pipeline is provided in the outer ring of the bearing, a lower ferrule joint is fixedly connected to the lower flange, and the lower ferrule joint connects the outer ring inert gas purge pipeline with the external inert dry gas pipeline.

[0021] Furthermore, the outer bracket includes a center column and a plurality of connecting rods, the center column is vertically arranged, and a through hole for the bolt to vertically pass through is opened in the middle of the center column, one end of the connecting rod is fixed to the outer wall of the center column, and the other end of the connecting rod is horizontally fixed to the inner wall of the annular cavity wall, and the plurality of connecting rods are distributed along the circumferential direction of the center column, wherein the structure of the inner bracket is the same as that of the outer bracket.

[0022] The present invention adopts the above technical solution, which has the following beneficial effects:

[0023] 1. By setting a regulating component in the annular cavity wall, the internal flow of the rotary joint device can be guaranteed to be stable, the fluid state parameters can be adjusted, and the adverse effects of the "backflow" phenomenon can be avoided, thus overcoming the defects of the prior art;

[0024] 2. By setting up a vacuum insulation layer between the annular cavity wall and the annular bearing, the temperature difference between the inside and outside of the flow-through parts is effectively reduced to prevent icing and mechanical failure of the rotary joint parts. The problem of the ultra-low temperature liquid phase inside the rotary joint being vaporized into a gas phase, causing a sharp increase in the operating pressure inside the rotary joint, is solved, thereby ensuring the safe and stable operation of the low-temperature transportation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

[0026] Figure 1 is a schematic diagram of the overall structure of a rotary joint device provided by an embodiment of the present invention;

[0027] Figure 2 is a structural schematic diagram of a regulating component of a rotary joint device provided by an embodiment of the present invention;

[0028] Figure 3 It is a schematic diagram of the assembly structure of an outer bracket and an inner bracket of a rotary joint device provided by an embodiment of the present invention;

[0029] Figure 4 is a structural schematic diagram of a sealing assembly of a rotary joint device provided by an embodiment of the present invention;

[0030] Figure 5 is a structural schematic diagram of a vibration-damping spring of a rotary joint device provided by an embodiment of the present invention;

[0031] Figure 6 It is a structural schematic diagram of an annular bearing of a rotary joint device provided in an embodiment of the present invention.

[0032] The symbols in the accompanying drawings are as follows:

[0033] 1. Annular cavity wall; 11. Low-temperature fluid channel; 12. Inner convex part; 121. Upper arc section; 1211. Sealing groove; 1212. Storage groove; 122. Lower arc section; 13. Upper cavity wall; 14. Lower cavity wall; 2. Control assembly; 21. Flow guide; 211. Direct flow section; 2111. Pressure balance hole; 212. First expansion section; 213. Second expansion section; 22. Flow control mechanism; 221. External bracket; 2211. Center column; 2212. Connecting rod; 222. Internal bracket; 223. Positioning nut; 224. Bolt; 3 , sealing assembly; 31, sealing ring; 32, compression spring; 4, annular bearing; 41, upper flange; 411, inner ring sealing ring; 412, upper sealing ring; 42, lower flange; 421, outer ring sealing ring; 422, lower sealing ring; 43, bearing inner ring; 431, inner ring inert gas purge pipeline; 44, bearing outer ring; 441, outer ring inert gas purge pipeline; 45, ball bearing; 46, clamping groove; 47, gasket; 5, vacuum insulation layer; 51, vibration damping spring; 6, upper ferrule joint; 7, lower ferrule joint. DETAILED DESCRIPTION

[0034] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0035] Since the existing rotary joint device has unstable low-temperature fluid flow during operation, the present invention provides a rotary joint device for an ultra-low temperature unloading transmission system, including an annular cavity wall and a regulating component, a low-temperature fluid channel is formed in the annular cavity wall, the regulating component includes a flow guide and a flow regulating mechanism, the flow guide includes a direct current section, a first expansion section and a second expansion section which are integrally formed from top to bottom, so that the low-temperature fluid can flow from the middle area of ​​the annular cavity wall to the edge area along the outer wall of the flow guide while entering the rotary joint and flowing downward, and the truncated cone structure of the second expansion section can effectively prevent backflow, and the flow regulating mechanism includes an outer bracket, an inner bracket, a positioning nut and a bolt, so that the flow regulating mechanism can control the flow guide to move up and down, so as to control the size of the flow channel between the flow guide and the annular cavity wall, thereby achieving the effect of flexible flow regulation and ensuring stable flow inside the rotary joint device.

[0036] The scheme of the present invention is described in detail below through examples.

[0037] Example

[0038] like Figure 1 and Figure 2 As shown, the present invention provides a rotary joint device for an ultra-low temperature unloading transmission system, including an annular cavity wall 1 and a regulating component 2. A low-temperature fluid channel 11 flowing from top to bottom is formed in the annular cavity wall 1. The regulating component 2 is arranged in the low-temperature fluid channel 11, including a flow guide 21 and a flow regulating mechanism 22. The flow guide 21 includes a direct flow section 211, a first flow expansion section 212 and a second flow expansion section 213 which are integrally formed from top to bottom. The direct flow section 211 is a cylindrical structure, and the first flow expansion section 212 and the second flow expansion section 213 are both truncated cone structures, and the diameter of the bottom surface of the second flow expansion section 213 is greater than the diameter of the bottom surface of the first flow expansion section 212. Among them, the direct flow section 211 is arranged with the annular cavity wall 1 on the same central axis, and an annular flow passage is formed between the outer wall of the flow guide 21 and the inner wall of the annular cavity wall 1.

[0039] Among them, according to the law of fluid flow phenomenon inside the traditional rotary joint, it can be known that when LNG or liquid hydrogen flows inside the rotary joint, the flow velocity along the axial direction close to the middle area is high and unstable, and the flow velocity along the edge area is relatively low but the flow is uneven. Therefore, it is necessary to set the flow guide and flow parameter control in the corresponding area according to the law of the flow. Through the setting of the above structure, when the low-temperature fluid enters the annular cavity wall 1 along the low-temperature fluid channel 11, the low-temperature fluid enters the interior of the rotary joint and flows downward. At the same time, it can flow from the middle area of ​​the annular cavity wall 1 to the edge area along the outer wall of the guide 21, so that the low-temperature fluid in the rotary joint has a high flow rate and stable and uniform flow. In addition, when the "backflow" phenomenon occurs in the flow process inside the rotary joint, that is, the counterflow of the low-temperature fluid occurs along the opposite flow direction, the truncated cone structure based on the bottom diameter of the second expansion section 213 of the guide 21 is larger than the top diameter can significantly suppress the backflow. In terms of the working principle, this conical anti-backflow structure can reduce the flow resistance of the inner wall boundary layer when the low-temperature medium flows from top to bottom along the low-temperature fluid channel 11, which is beneficial to the flow. At the same time, when reverse flow, i.e., backflow, occurs in the corresponding area inside the rotary joint, the above structure can cause the reverse flow process to form a vortex effect, thereby greatly increasing the reverse flow resistance, that is, achieving the effect of reducing backflow.

[0040] Furthermore, the interior of the flow guide 21 is a hollow structure, a pressure balance hole 2111 is provided on the top surface of the direct flow section 211, and the bottom surface of the second expansion section 213 is open. With the arrangement of this structure, when the cryogenic fluid enters the annular cavity wall 1 along the cryogenic fluid channel 11, it flows downstream along the outer walls of the direct flow section 211, the first expansion section 212, and the second expansion section 213 in sequence, and a part of the cryogenic fluid also flows in from the position of the pressure balance hole 2111, thereby preventing the occurrence of internal "entrainment".

[0041] A flow guide and flow control device is arranged at the position of the rotary joint, and the device is composed of a direct flow section, a first flow expansion section, a second flow expansion section, an inner bracket, an outer bracket, a positioning nut and a bolt, etc. A pressure balance hole is arranged at the top of the device. When the cryogenic fluid enters the interior of the rotary joint along the flow direction shown in the figure, it flows downstream along the direct flow section, the first flow expansion section, and the second flow expansion section in sequence. A part of the cryogenic fluid will also flow in from the position of the pressure balance hole. The purpose of setting the pressure balance hole is to prevent the occurrence of an internal "entrainment" scene. According to the fluid mechanics calculation and the corresponding test results, the internal angle of the first flow expansion section 212 is taken as α, and the range of α is 65°-75°, and the internal angle of the second flow expansion section 213 is taken as β, and the range of β is 85°-95°.

[0042] As mentioned above, combined Figure 1-Figure 3 As shown, the flow control mechanism 22 includes an outer bracket 221, an inner bracket 222, a positioning nut 223 and a bolt 224. The outer bracket 221 is horizontally arranged in the low-temperature fluid channel 11, and the outer bracket 221 is fixedly connected to the inner wall of the annular cavity wall 1. The inner bracket 222 is horizontally arranged in the flow guide 21, and the inner bracket 222 is fixedly connected to the flow guide 21. The bolt 224 is vertically fixed to the inner bracket 222, and the bolt 224 is connected to the outer bracket 221 by moving up and down. The positioning nut 223 is threadedly connected to the bolt 224, and a positioning nut 223 is respectively arranged above and below the outer bracket 221. Among them, the positioning nut 223 is pressed against the horizontal surface of the outer bracket 221 after being tightened. By using positioning nuts 223 provided on the upper and lower parts of the outer bracket 221, which are fixed up and down by the two positioning nuts 223, it is only necessary to adjust the positions of the two positioning nuts 223 on the bolts 224, that is, to adjust the up and down movement of the guide member 21 in the axial position, thereby realizing the change of the cross-sectional area of ​​the flow channel, and further achieving the effect of flexible flow control.

[0043] Furthermore, the outer support 221 includes a central column 2211 and a plurality of connecting rods 2212. The central column 2211 is vertically arranged, and a through hole for the bolt 224 to vertically pass through is provided in the middle of the central column 2211. One end of the connecting rod 2212 is fixedly connected to the outer wall of the central column 2211, and the other end of the connecting rod 2212 is horizontally fixedly connected to the inner wall of the annular cavity wall 1, and the plurality of connecting rods 2212 are distributed along the circumferential direction of the central column 2211. Among them, the structural principle of the inner support 222 is the same as that of the outer support 221, and the size of the inner support 222 is smaller than that of the outer support 221.

[0044] Furthermore, the inner wall of the annular cavity wall 1 located at the first expansion section 212 and the second expansion section 213 bulges inward and forms an annular inner convex portion 12. The upper surface of the inner convex portion 12 is a curved surface structure and constitutes an upper arc segment 121, and an annular flow guide area is formed between the upper arc segment 121 and the outer walls of the first expansion section 212 and the second expansion section 213. The lower surface of the inner convex portion 12 is a curved surface structure and constitutes a lower arc segment 122, and an annular flow channel area is formed between the lower arc segment 122 and the outer wall of the second expansion section 213. Based on the setting of this structure, by adjusting the flow guide 21 to rise and fall in the axial position, the change of the cross-sectional area of ​​the flow channel area is realized, thereby achieving the effect of flexible flow control.

[0045] Furthermore, combined with Figure 4 As shown, the annular cavity wall 1 includes an upper cavity wall 13 and a lower cavity wall 14. The inner wall at the bottom end of the upper cavity wall 13 bulges inward and constitutes the upper arc segment 121 of the inner convex portion 12, and the inner wall at the top end of the lower cavity wall 14 bulges inward and constitutes the lower arc segment 122 of the inner convex portion 12. A sealing assembly 3 is provided between the upper arc segment 121 and the lower arc segment 122, and the sealing assembly 3 includes a sealing ring 31 and a compression spring 32. An annular sealing groove 1211 is provided on the bottom end surface of the upper arc segment 121, and an annular receiving groove 1212 is provided on the inner bottom surface of the sealing groove 1211. The sealing ring 31 is assembled in the sealing groove 1211, and a plurality of compression springs 32 are arranged in the receiving groove 1212 along the circumferential direction. Among them, at least one group of sealing assemblies 3 is arranged from the inside to the outside of the annular cavity wall 1, and the inner diameters of the plurality of sealing rings 31 increase in sequence from the inside to the outside of the annular cavity wall 1. Through the arrangement of this structure, after the upper cavity wall 13 and the lower cavity wall 14 are butted, the sealing ring 31 on the upper cavity wall 13 is tightly pressed against the top surface of the lower cavity wall 14 through the compression spring 32 at the top, thereby achieving fixation and sealing. Among them, the material of the sealing ring 31 is preferably one of polytetrafluoroethylene, polyimide, and polyperfluoroethylene propylene, which can meet the sealing requirements of ultra-low temperature working conditions, and the sealing ring 31 can realize relative rotation between the upper cavity wall 13 and the lower cavity wall 14 while still ensuring the sealing effect.

[0046] Furthermore, an annular bearing 4 is sleeved on the outer side of the annular cavity wall 1, an upper flange 41 is fixedly connected above the annular bearing 4, and the top end of the upper flange 41 is interconnected with the upper cavity wall 13. A lower flange 42 is fixedly connected below the annular bearing 4, and the bottom end of the lower flange 42 is interconnected with the lower cavity wall 14, and the inner wall of the upper flange 41, the inner wall of the lower flange 42 and the inner wall of the annular bearing 4 together form a vacuum insulation layer 5 with the outer cavity wall of the annular cavity wall 1. Through the arrangement of this structure, the upper flange 41 and the upstream cryogenic fluid pipeline are interconnected, and the lower flange 42 and the downstream cryogenic fluid pipeline are interconnected, so that the cryogenic medium such as LNG or liquid hydrogen from the upstream enters the interior of the rotary joint device along the cryogenic fluid channel 11 and enters the downstream pipeline. At the same time, vacuum insulation is used to achieve cold insulation of ultra-low temperature liquid phase medium. Vacuum is the most effective way of cold insulation and is particularly suitable for the technical working conditions involved in the present invention, such as LNG temperature of -163°C and liquid hydrogen temperature of -253°C. This can prevent the ultra-low temperature inside the rotary joint from being transmitted to the outside, reduce the gasification of cryogenic liquid, and effectively prevent safety problems caused by internal overpressure.

[0047] Among them, combined Figure 1 and Figure 5 As shown, a vertically arranged damping spring 51 is provided in the vacuum insulation layer 5, one side of the damping spring 51 is fixedly connected to the outer cavity wall of the annular cavity wall 1, and the other side of the damping spring 51 is fixedly connected to the inner wall of the annular bearing 4. Through the arrangement of this structure, on the one hand, when the flow vibration inside the rotary joint is large, the damping spring 51 can buffer or offset the vibration phenomenon; on the other hand, the damping spring 51 also constitutes a support member of the vacuum insulation layer 5, thereby improving the stability of the system structure.

[0048] Furthermore, combined with Figure 1 and Figure 6As shown, the annular bearing 4 includes a bearing inner ring 43, a bearing outer ring 44 and a ball bearing 45. The bearing outer ring 44 is fixedly connected to the lower flange 42, and the bearing inner ring 43 is fixedly connected to the upper flange 41. The bearing inner ring 43 is arranged inside the bearing outer ring 44, and the outer wall of the bearing inner ring 43 is arranged close to the inner wall of the bearing outer ring 44. A first semicircular annular groove is provided on the outer wall of the bearing inner ring 43, and a second semicircular annular groove corresponding to the first semicircular annular groove is provided on the inner wall of the bearing outer ring 44. The first semicircular annular groove and the second semicircular annular groove together constitute a clamping groove 46, and the ball bearing 45 is assembled in the clamping groove 46. Through the setting of this structure, through the setting of this structure, using the structure of the annular bearing 4, the bearing inner ring 43 and the bearing outer ring 44 can achieve relative rotation, and then the upper flange 41 and the lower flange 42 can achieve relative rotation, so as to realize the flexible adjustment of the direction of the pipeline where the upper flange 41 and the lower flange 42 are located. Among them, the ball bearing 45 is subjected to a large local alternating load during operation, and a great contact stress is generated between the rolling element and the bearing inner ring 43 and the bearing outer ring 44. Therefore, the bearing steel is required to have high hardness, wear resistance, sufficient fatigue strength, certain toughness, corrosion resistance, good dimensional stability, etc. The material of the ball bearing 45 is preferably the following three types: GCr15 (i.e. 52100) high carbon chromium bearing steel, which has high density, uniform carbonization, and fatigue resistance. Heavy metal elements such as manganese or molybdenum can usually be added to improve hardenability and rigidity; SUS440C (i.e. 9Cr18) stainless steel has high precision and is therefore widely used in applications in humid and corrosive environments; ceramic bearings can be used in extremely harsh environments and special working conditions, because they have the characteristics of a wide operating temperature range, good wear resistance, corrosion resistance, insulation, oil-free self-lubrication, high speed, etc. Ceramic bearings are usually composed of three materials: zirconium oxide (ZrO2), silicon nitride (Si3N4), and silicon carbide (Sic). The gasket material is preferably one of polytetrafluoroethylene, polyimide, and polyperfluoroethylene propylene, which has the advantages of good wear resistance, light weight, high toughness, etc.

[0049] Among them, a gasket 47 is provided between two adjacent balls in the ball bearing 45. Through the combination of the ball bearing 45 and the gasket 47, the balls in the ball bearing 45 and the plurality of gaskets 47 are arranged at intervals. Compared with the conventional method of using all ball bearings, on the one hand, the overall weight can be reduced, and on the other hand, during use, the friction stress between adjacent balls can be reduced by isolating the gasket 47, and the noise can be effectively reduced.

[0050] Furthermore, the outer ring 44 of the bearing is fixedly connected to the lower flange 42 by bolts, an outer ring seal 421 is embedded between the contact interface between the lower flange 42 and the outer ring 44 of the bearing, and a lower seal 422 is embedded between the contact interface between the lower flange 42 and the inner ring 43 of the bearing. The inner ring 43 of the bearing is fixedly connected to the upper flange 41 by bolts, an inner ring seal 411 is embedded between the contact interface between the upper flange 41 and the inner ring 43 of the bearing, and an upper seal 412 is embedded between the contact interface between the upper flange 41 and the outer ring 44 of the bearing. The sealing structure is provided to isolate the intrusion of external water vapor.

[0051] Furthermore, an annular inner ring inert gas purge pipeline 431 is provided in the inner ring 43 of the bearing, an upper ferrule joint 6 is fixedly connected to the upper flange 41, and the upper ferrule joint 6 connects the inner ring inert gas purge pipeline 431 with the external inert dry gas pipeline. An annular outer ring inert gas purge pipeline 441 is provided in the outer ring 44 of the bearing, a lower ferrule joint 7 is fixedly connected to the lower flange 42, and the lower ferrule joint 7 connects the outer ring inert gas purge pipeline 441 with the external inert dry gas pipeline. Through the setting of this structure, the upper ferrule joint 6 and the lower ferrule joint 7 are respectively connected to the inert dry gas pipeline, and circulating nitrogen is continuously introduced during the use of the rotary joint device, thereby realizing dry protection of the annular bearing 4, isolating the intrusion of external water vapor, and preventing condensation and icing inside the rotary joint device. Inert gas delivery channels are formed in both the upper ferrule joint 6 and the lower ferrule joint 7, and dry nitrogen is usually used as the inert gas.

[0052] The rotary joint device of the present invention has the following beneficial effects:

[0053] 1. Inert gas is used to purge and isolate the intrusion of external water vapor, effectively reducing the temperature difference between the inside and outside of the flow-through parts to prevent icing and mechanical failure of the rotary joint parts. The inner wall of the upper flange 41, the inner wall of the lower flange 42 and the inner wall of the annular bearing 4 together form a vacuum insulation layer 5 with the outer cavity wall of the annular cavity wall 1 to solve the problem that the ultra-low temperature liquid phase inside the rotary joint is vaporized into a gas phase, causing the operating pressure inside the rotary joint to increase sharply, thereby ensuring the safe and stable operation of the low-temperature transportation system.

[0054] 2. The vibration-damping spring 51 in the vacuum insulation layer 5 can reduce the vibration phenomenon in the fluid transportation process and increase the stability of the system structure. By setting the regulating component 2 in the annular cavity wall 1, the internal flow of the rotary joint device can be guaranteed to be stable, and the fluid state parameters can be adjusted. At the same time, the adverse effects of the "backflow" phenomenon are avoided, thereby overcoming the defects of the prior art.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rotary joint device for an ultra-low temperature unloading transmission system, characterized in that: The ultra-low temperature unloading transmission system rotary joint device includes an annular cavity wall and a regulating component, wherein a low temperature fluid channel flowing from top to bottom is formed in the annular cavity wall, and the regulating component is arranged in the low temperature fluid channel, including a flow guide and a flow regulating mechanism; The flow guide comprises a direct flow section, a first flow expansion section and a second flow expansion section which are integrally formed from top to bottom, the direct flow section is a cylindrical structure, the first flow expansion section and the second flow expansion section are both truncated cone structures, and the diameter of the bottom surface of the second flow expansion section is greater than the diameter of the bottom surface of the first flow expansion section, wherein the direct flow section and the annular cavity wall are arranged with a central axis, and a flow passage is formed between the outer wall of the flow guide and the inner wall of the annular cavity wall; The flow control mechanism includes an outer bracket, an inner bracket, a positioning nut and a bolt, wherein the outer bracket is horizontally arranged in the low-temperature fluid channel and fixedly connected to the inner wall of the annular cavity wall, the inner bracket is horizontally arranged in the flow guide and fixedly connected to the flow guide, the bolt is vertically fixed to the inner bracket and connected to the outer bracket by moving up and down, the positioning nut is threadedly connected to the bolt, and one positioning nut is respectively arranged above and below the outer bracket; The inner wall of the annular cavity wall located at the first diffuser section and the second diffuser section bulges inward to form an annular inner convex portion, the upper side surface of the inner convex portion is a curved surface structure and constitutes an upper arc segment, and an annular flow guide area is formed between the upper arc segment and the outer walls of the first diffuser section and the second diffuser section, and the lower side surface of the inner convex portion is a curved surface structure and constitutes a lower arc segment, and an annular flow channel area is formed between the lower arc segment and the outer wall of the second diffuser section; The annular cavity wall comprises an upper cavity wall and a lower cavity wall, the inner wall of the bottom end of the upper cavity wall protrudes inwardly and constitutes an upper arc segment of the inner convex portion, the inner wall of the top end of the lower cavity wall protrudes inwardly and constitutes a lower arc segment of the inner convex portion, a sealing assembly is provided between the upper arc segment and the lower arc segment, the sealing assembly comprises a sealing ring and a compression spring, an annular sealing groove is provided on the bottom end surface of the upper arc segment, an annular receiving groove is provided on the inner bottom surface of the sealing groove, the sealing ring is fitted in the sealing groove, and a plurality of compression springs are provided in the receiving groove along the circumferential direction, wherein at least one group of the sealing assembly is arranged from the inside to the outside of the annular cavity wall, and the inner diameters of the plurality of sealing rings increase successively from the inside to the outside of the annular cavity wall.

2. The ultra-low temperature unloading transmission system rotary joint device according to claim 1 is characterized in that: The interior of the flow guide is a hollow structure, a pressure balance hole is opened on the top surface of the direct flow section, and the bottom surface of the second flow expansion section is open.

3. The ultra-low temperature unloading transmission system rotary joint device according to claim 1, characterized in that: The internal angle range of the first expansion section is 65°-75°, and the internal angle range of the second expansion section is 85°-95°.

4. The ultra-low temperature unloading transmission system rotary joint device according to claim 1, characterized in that: An annular bearing is sleeved on the outer side of the annular cavity wall, an upper flange is fixedly connected above the annular bearing, the top of the upper flange is interconnected with the upper cavity wall, a lower flange is fixedly connected below the annular bearing, the bottom end of the lower flange is interconnected with the lower cavity wall, and the inner wall of the upper flange, the inner wall of the lower flange and the inner wall of the annular bearing together form a vacuum insulation layer with the outer cavity wall of the annular cavity wall, a vertically arranged damping spring is provided in the vacuum insulation layer, one side of the damping spring is fixedly connected to the outer cavity wall of the annular cavity wall, and the other side of the damping spring is fixedly connected to the inner wall of the annular bearing.

5. The ultra-low temperature unloading transmission system rotary joint device according to claim 4, characterized in that: The annular bearing includes a bearing inner ring, a bearing outer ring and a ball bearing, the bearing outer ring is fixedly connected to the lower flange, the bearing inner ring is fixedly connected to the upper flange, the bearing inner ring is arranged on the inner side of the bearing outer ring, and the outer wall of the bearing inner ring is arranged tightly against the inner wall of the bearing outer ring, a first semicircular annular groove is opened on the outer wall of the bearing inner ring, and a second semicircular annular groove corresponding to the first semicircular annular groove is opened on the inner wall of the bearing outer ring, the first semicircular annular groove and the second semicircular annular groove together constitute a clamping groove, the ball bearing is assembled in the clamping groove, and a gasket is provided between two adjacent balls in the ball bearing.

6. The ultra-low temperature unloading transmission system rotary joint device according to claim 5, characterized in that: The outer ring of the bearing is fixedly connected to the lower flange by bolts, an outer ring sealing ring is embedded between the contact interface between the lower flange and the outer ring of the bearing, and a lower sealing ring is embedded between the contact interface between the lower flange and the inner ring of the bearing. The inner ring of the bearing is fixedly connected to the upper flange by bolts, an inner ring sealing ring is embedded between the contact interface between the upper flange and the inner ring of the bearing, and an upper sealing ring is embedded between the contact interface between the upper flange and the outer ring of the bearing.

7. The ultra-low temperature unloading transmission system rotary joint device according to claim 6, characterized in that: An annular inner ring inert gas purge pipeline is provided in the inner ring of the bearing, an upper ferrule joint is fixedly connected to the upper flange, and the upper ferrule joint connects the inner ring inert gas purge pipeline with an external inert dry gas pipeline; an annular outer ring inert gas purge pipeline is provided in the outer ring of the bearing, a lower ferrule joint is fixedly connected to the lower flange, and the lower ferrule joint connects the outer ring inert gas purge pipeline with an external inert dry gas pipeline.

8. The ultra-low temperature unloading transmission system rotary joint device according to claim 1, characterized in that: The outer bracket includes a center column and a plurality of connecting rods. The center column is vertically arranged, and a through hole for the bolt to vertically pass through is opened in the middle of the center column. One end of the connecting rod is fixed to the outer wall of the center column, and the other end of the connecting rod is horizontally fixed to the inner wall of the annular cavity wall. The plurality of connecting rods are distributed along the circumferential direction of the center column, wherein the structure of the inner bracket is the same as that of the outer bracket.

Images