Maintenance-free sealing system and electrical transmission device

Abstract

The application discloses a kind of maintenance-free sealing systems and electric transmission equipment, it is related to electric transmission equipment technical field, maintenance-free sealing system includes main shaft sleeve, body and two sealing assemblies, two sealing assemblies are all including one dynamic seal ring and one static seal ring, main shaft sleeve is used to set fixed on main shaft, body is used to fixedly arranged on turret casing, dynamic seal ring is along the axial direction of main shaft sleeve with interval set on main shaft sleeve and can rotate with main shaft, one static seal ring corresponds one dynamic seal ring, static seal ring is arranged on body and has the freedom of movement along the axial direction, static seal ring is in the end surface of dynamic seal ring and is formed sealing pair under the action of preset elastic force;Two sealing assemblies, main shaft sleeve and body are structured with a sealing cavity;Sealing cavity is used for presetting isolation liquid, dynamic seal ring and static seal ring are made of ceramic or hard alloy material.The application can make single point mooring system electric transmission channel long-term, reliable, stable operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric transmission equipment, in particular to a maintenance-free sealing system and electric transmission equipment. BACKGROUND

[0002] The single point mooring system is the core equipment in the fields of offshore floating production storage and offloading, offshore wind power operation and maintenance, etc. The turret part needs to realize the rotary connection between the hull and the underwater pipe cable. High-voltage electric energy is transmitted through the slip ring device installed in the turret, which is the key to ensure the operation of the upper facilities. Since such equipment is usually located at sea level, the inside of the electric transmission channel is filled with insulating medium to ensure safety, so the sealing performance of the rotary connection is extremely demanding: it must be able to effectively seal the internal insulating medium for a long time and resist the erosion of external harsh marine environments such as high salt mist, ultraviolet light, and large temperature difference.

[0003] At present, the existing technology applied to such rotary sealing generally adopts a rotary sealing ring scheme. The most common one is a sealing element based on elastic materials (such as rubber), such as a skeleton oil seal, an O-shaped sealing ring, or a packing seal using graphite and other materials. To further improve reliability, multiple sealing structures have also appeared, such as the combination of high-performance polymers and metal sealing elements (such as 316 stainless steel shells) to form multiple sealing barriers.

[0004] However, these existing technical solutions have obvious limitations. First, in terms of sealing pressure, conventional sealing structures are usually only suitable for low-pressure working conditions (generally below 0.2 MPa), and it is difficult to meet the higher medium pressure sealing requirements required by higher power electric transmission. Second, in terms of durability, conventional sealing materials are prone to aging, wear and failure under long-term salt mist corrosion, ultraviolet aging, high and low temperature alternation, and uncertain direction swing working conditions of the turret, and cannot achieve the same design full life cycle (such as 25 years) as the main body of the equipment.

[0005] Therefore, there is an urgent need in the art for an integrated sealing solution that can adapt to high pressure and harsh environments and achieve ultra-long life maintenance-free operation to overcome the above-mentioned deficiencies of the prior art and ensure the long-term, reliable and stable operation of the electric transmission channel of the single point mooring system. SUMMARY

[0006] The purpose of the present application is to provide a maintenance-free sealing system and electric transmission equipment to solve the above-mentioned problems existing in the prior art and ensure the long-term, reliable and stable operation of the electric transmission channel of the single point mooring system.

[0007] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0008] The application provides a maintenance-free sealing system, which comprises a main shaft sleeve, a body and two sealing assemblies, each of the two sealing assemblies comprises a dynamic sealing ring and a static sealing ring, the main shaft sleeve is arranged on the main shaft, the body is arranged on the turret shell, the dynamic sealing ring is arranged on the main shaft sleeve along the axial direction of the main shaft sleeve and can rotate with the main shaft, one static sealing ring corresponds to one dynamic sealing ring, the static sealing ring is arranged on the body and has the freedom of moving along the axial direction, and the static sealing ring is in contact with the end surface of the dynamic sealing ring to form a sealing pair under the action of a preset elastic force; a sealing cavity is formed between the two sealing assemblies, the main shaft sleeve and the body; the sealing cavity is used for preloading the isolation liquid, and the dynamic sealing ring and the static sealing ring are made of ceramic or hard alloy material.

[0009] Preferably, the application further comprises a bearing, which is used for providing rotary support for the main shaft; the bearing is arranged in the sealing cavity or outside the sealing cavity; when the bearing is arranged in the sealing cavity, the bearing is located between the two sealing assemblies.

[0010] Preferably, the application further comprises a sliding sleeve, the bearing is arranged in the sealing cavity, the sliding sleeve is arranged on the outer surface of the main shaft sleeve and can slide along the axial direction of the main shaft sleeve, the sliding sleeve is in transmission connection with the main shaft sleeve through a key, the sliding sleeve and the inner ring of the bearing are fixedly connected through interference fit, the body and the outer ring of the bearing are fixedly connected through interference fit, the interference fit between the sliding sleeve and the inner ring of the bearing forms a rotary assembly, the rotary assembly can slide along the axial direction of the main shaft sleeve to compensate for the thermal expansion and contraction amount caused by temperature change between the main shaft sleeve and the rotary assembly, and the dynamic sealing ring in at least one sealing assembly and the rotary assembly are provided with a force transmission structure and are installed in a manner allowing the dynamic sealing ring to be axially displaced to adapt to deformation when the dynamic sealing ring is subjected to the axial thrust generated by the thermal expansion of the rotary assembly.

[0011] Preferably, the application further comprises a constant-pressure dynamic suppression system, which is used for providing and maintaining the isolation liquid in the sealing cavity at a pressure higher than that of the sealed medium.

[0012] Preferably, the bearing is arranged in the sealing cavity, the two sealing assemblies are arranged one above the other, and an isolation ring is arranged between the upper sealing assembly and the bearing.

[0013] Preferably, the isolation liquid is lubricating oil.

[0014] Preferably, the preset elastic force is from a spring arranged in the body, and under normal circumstances, the spring is in a compressed state and one end of the spring abuts against the side of the static sealing ring away from the dynamic sealing ring.

[0015] Preferably, one end of the main shaft sleeve close to the medium is integrally provided with an annular clamping groove facing the static sealing ring, one of the dynamic sealing rings is arranged in the annular clamping groove, and a sealing ring is arranged between the wall surface of the annular clamping groove and the wall surface of the dynamic sealing ring; one end of the main shaft sleeve close to the external atmosphere is provided with a driving ring, the main shaft sleeve and the driving ring are connected with the main shaft through bolts; one end of the driving ring abuts against the end of the sliding shaft sleeve; a limiting portion is arranged on the driving ring, and the other dynamic sealing ring is sleeved on the driving ring and is limited by the limiting portion from moving axially away from the static sealing ring.

[0016] Preferably, the constant pressure dynamic inhibition system comprises a liquid storage tank, a pressure compensator, a liquid supplement pump, an isolation liquid tank, monitoring instruments and a control system; the liquid outlet of the liquid storage tank is connected to the isolation liquid inlet of the sealed cavity through a liquid supply pipeline; the pressure compensator is connected to the liquid storage tank or the liquid supply pipeline, used for pre-charging pressure and maintaining the stability of the basic pressure of the system; the inlet of the liquid supplement pump is communicated with the isolation liquid tank, and the outlet is communicated with the liquid storage tank; the monitoring instruments comprise a pressure transmitter, a temperature sensor and a liquid level sensor, the pressure transmitter is arranged on the liquid supply pipeline and / or the liquid storage tank, used for detecting the pressure of the isolation liquid in real time; the temperature detection end of the temperature sensor is communicated with the isolation liquid outlet of the sealed cavity, used for detecting the temperature of the isolation liquid in the sealed cavity in real time; the liquid level sensor is arranged in the isolation liquid tank, used for monitoring the liquid level of the isolation liquid in real time; the control system is signal connected with the pressure transmitter, the temperature sensor, the liquid level sensor and the liquid supplement pump; the control system is configured to receive the signals of the monitoring instruments and control the operation of the liquid supplement pump according to the signals; when the pressure value detected by the pressure transmitter is lower than a first pressure setting value, the liquid supplement pump is controlled to start and pump the isolation liquid from the isolation liquid tank to the liquid storage tank; when the pressure value reaches a second pressure setting value higher than the first pressure setting value, the liquid supplement pump is controlled to stop; when the liquid level detected by the liquid level sensor is lower than or higher than a set range, the control system sends an alarm signal.

[0017] The application further provides an electric transmission device for a single-point mooring system, comprising a turret shell, a main shaft and the maintenance-free sealing system as described above, the turret shell is filled with a sealed medium, the sealed medium is an insulating medium, an installation opening penetrating along the thickness direction of the turret shell is formed on the turret shell, and the main shaft penetrates the installation opening; the maintenance-free sealing system is sleeved on the main shaft at the installation opening and used for sealing the installation opening.

[0018] The application has the following technical effects relative to the prior art:

[0019] First, since the dynamic sealing ring and the static sealing ring are made of ceramic or hard alloy material, these materials have extremely high hardness, compressive strength and deformation resistance, and can withstand higher medium pressure without irreversible deformation or damage. In addition, the static sealing ring has axial movement freedom and is tightly attached to the end face of the dynamic ring under the action of the pre-tightening force, ensuring that the sealing pair can still maintain good followability and contact when the pressure fluctuates, avoiding the opening and leakage of the sealing interface due to pressure rise. Therefore, the application can be stably applied to higher pressure insulation medium environment (for example, ≥0.8MPa), and the limitation of traditional sealing on the improvement of electric transmission power is solved, providing higher power electric power transmission guarantee for a single power generation equipment.

[0020] Second, ceramic and hard alloy have natural inertia to salt spray corrosion and ultraviolet radiation, and their performance will not decay due to these environmental factors, solving the fundamental defects of elastic materials such as aging, embrittlement and cracking. In addition, ceramic and hard alloy have small thermal expansion coefficient and good dimensional stability under high and low temperature alternating conditions, avoiding thermal deformation or thermal cracking of the sealing surface due to large temperature difference, and ensuring the reliability of the sealing performance.

[0021] Third, the bearing and the two sets of sealing assembly are integrated in one body, ensuring high coaxiality and installation accuracy, and fundamentally reducing the eccentric wear and abnormal wear caused by centering error. Therefore, the sealing assembly system described in the application has a super-long service life in harsh marine environments and can realize "maintenance-free" operation with the same life cycle as the main equipment, completely avoiding the huge operating cost and yield loss caused by frequent shutdown and replacement of the seal. In addition, the integrated design ensures the concentricity of the bearing and the seal. Even if there is a swing, the entire rotating assembly is moving as a whole, and the internal relative displacement is very small, protecting the precise sealing interface. Therefore, the system described in the embodiment can better adapt to the uncertain direction swing in the operation of the rotating tower, and has higher operation stability and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 The structure schematic diagram of the maintenance-free sealing system provided by one embodiment of the application is shown in the figure.

[0024] Figure 2 The structure schematic diagram of the maintenance-free sealing system provided by another embodiment of the application is shown in the figure.

[0025] Figure 3 Structure diagram of the maintenance-free sealing system of the present application; Figure 1 and Figure 2 Structure diagram of the maintenance-free sealing system of the present application;

[0026] Figure 4 Structure diagram of the maintenance-free sealing system of the present application;

[0027] Figure 5 Structure diagram of the maintenance-free sealing system of the present application; Figure 3 Enlarged view of A in

[0028] Figure 6 Enlarged view of B in Figure 3

[0029] Structure diagram of the sealing assembly of the driving ring and the atmosphere side of the present application; Figure 7 Figure 2 Structure diagram of the sealing assembly of the driving ring and the atmosphere side of the present application;

[0030] Figure 8 Figure 7 Sectional view of

[0031] Figure 9 Structure diagram of the sealing assembly of the main shaft sleeve and the medium side of the present application; Figure 2

[0032] Structure diagram of the sealing assembly of the main shaft sleeve and the medium side of the present application; Figure 10 Figure 9 Structure diagram of the sealing assembly of the driving ring, the main shaft sleeve and the medium side of the present application;

[0033] Figure 11 Sectional view of the overall structure of the sealing assembly of the main shaft sleeve, the driving ring and the medium side, and the dynamic sealing ring of the atmosphere side of the present application;

[0034] Figure 12 Figure 1 Sectional view of the overall structure of the sealing assembly of the main shaft sleeve, the driving ring and the medium side, and the dynamic sealing ring of the atmosphere side of the present application;

[0035] In the figure: 1 - body; 11 - medium side body; 12 - atmosphere side body; 2 - bearing; 3 - sealing assembly; 31 - static sealing ring; 32 - dynamic sealing ring; 33 - spring; 4 - main shaft sleeve; 41 - key; 42 - annular clamping groove; 5 - sliding shaft sleeve; 6 - isolation ring; 7 - driving ring; 71 - fixing bolt; 81 - isolation liquid outlet; 82 - isolation liquid inlet; 100 - main shaft; 200 - turret housing; 91 - liquid storage tank; 92 - pressure compensator; 93 - isolation liquid tank; 94 - liquid supplement pump. DETAILED DESCRIPTION

[0036] ​​​​With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0038] The embodiments of the present application will be described below with reference to the drawings. Figures 1 to 12

[0039] The present application provides a maintenance-free sealing system, comprising a main shaft sleeve 4, a body 1 and two sealing assemblies 3, each of the two sealing assemblies 3 comprises a dynamic sealing ring 32 and a static sealing ring 31, the main shaft sleeve 4 is arranged on the main shaft 100, the body 1 is arranged on the turret housing 200, the dynamic sealing ring 32 is arranged on the main shaft sleeve 4 along the axial direction of the main shaft sleeve 4 and can rotate with the main shaft 100, one static sealing ring 31 corresponds to one dynamic sealing ring 32, the static sealing ring 31 is arranged on the body 1 and has the freedom of moving along the axial direction, and the static sealing ring 31 is in contact with the end surface of the dynamic sealing ring 32 to form a sealing pair under the action of a preset elastic force; a sealing cavity is formed between the two sealing assemblies 3, the main shaft sleeve 4 and the body 1; the sealing cavity is used for preloading an isolation liquid, and the dynamic sealing ring 32 and the static sealing ring 31 are made of ceramic or hard alloy material, and a sealing ring is arranged between the main shaft sleeve 4 and the main shaft 100.

[0040] In the embodiment, the dynamic sealing ring 32 and the static sealing ring 31 are made of ceramic or hard alloy material, which has very high hardness, compressive strength and deformation resistance, and can withstand higher medium pressure without irreversible deformation or damage. In addition, the static sealing ring 31 has the freedom of moving along the axial direction and is in close contact with the end surface of the dynamic ring under the action of the pre-tightening force, which ensures that the sealing pair can still maintain good followability and contact when the pressure fluctuates, and avoids the opening and leakage of the sealing interface due to the increase of the pressure. Therefore, the present application can be stably applied to a higher pressure insulation medium environment (for example, ≥0.8 MPa), which eliminates the limitation of the traditional sealing on the improvement of the electric transmission power, provides higher power electric power transmission guarantee for a single power generation device, and in addition, ceramic and hard alloy have natural inertia to salt spray corrosion and ultraviolet radiation, and their performance will not decay due to these environmental factors, which solves the fundamental defects of the easy aging, embrittlement and cracking of the elastic material. The thermal expansion coefficient of ceramic and hard alloy is small, and the dimensional stability is good under high and low temperature alternating conditions, which avoids the thermal deformation or thermal cracking of the sealing surface due to the large temperature difference, and ensures the reliability of the sealing performance.​

[0041] In some embodiments, the application further comprises a bearing 2 for providing rotational support for the main shaft 100; the bearing 2 is disposed inside or outside the sealed cavity; when the bearing 2 is disposed inside the sealed cavity, the bearing 2 is located between the two sealing assemblies 3.

[0042] The embodiment includes two specific embodiments, the first is to dispose the bearing 2 outside the two sealing assemblies 3 forming an integral structure, and the second is to dispose the bearing 2 between the two sealing assemblies 3.

[0043] For the second scheme, the embodiment integrates the bearing 2 and the two sets of sealing assemblies 3 in one body 1, ensuring extremely high coaxiality and installation accuracy, and fundamentally reducing the eccentric error caused by eccentric wear and abnormal wear. Therefore, the sealing system described in the application has an ultra-long service life in harsh marine environments, can realize the "maintenance-free" operation with the same service life as the main equipment, and completely avoids the huge operating costs and yield losses caused by frequent shutdown and replacement of the sealing belt. In addition, the integrated design ensures the concentricity of the bearing 2 and the seal. Even if there is a swing, the entire rotating assembly is moving as a whole, and the internal relative displacement is extremely small, protecting the precise sealing interface. Therefore, the system described in the embodiment can better adapt to the uncertain direction swing in the operation of the rotating tower, and has higher operation stability and reliability.

[0044] In some embodiments, the isolation liquid is lubricating oil.

[0045] In this embodiment, the lubricating oil flows in the gap between the sealed cavity and the bearing 2, not only playing the role of isolating the medium, but also lubricating the bearing 2, simplifying the system structure (without the need for an independent bearing lubrication system), and improving the overall reliability.

[0046] In some embodiments, the application further comprises a sliding shaft sleeve 5, the bearing 2 is disposed inside the sealed cavity, the sliding shaft sleeve 5 is sleeved on the outside of the main shaft sleeve 4 in the axial direction and is in transmission connection with the main shaft sleeve 4 through the key 41; the sliding shaft sleeve 5 and the inner ring of the bearing 2 are in interference fit to realize fixed connection, and the body 1 and the outer ring of the bearing 2 are in interference fit to realize fixed connection; the interference fit between the sliding shaft sleeve 5 and the inner ring of the bearing 2 forms a rotating assembly, the rotating assembly can slide in the axial direction on the main shaft sleeve 4 to compensate for the thermal expansion and contraction amount between the main shaft sleeve 4 and the rotating assembly due to temperature changes, and the dynamic sealing ring 32 in at least one sealing assembly 3 and the rotating assembly are configured with a force transmission structure and its installation mode allows it to have axial displacement to adapt to deformation when subjected to the axial thrust generated by the thermal expansion of the rotating assembly.

[0047] In this embodiment, the rotating assembly composed of the sliding shaft sleeve 5 and the bearing inner ring can axially slide on the main shaft sleeve 4, directly compensating for the macroscopic size change (usually 0.2-0.8 mm) between the main shaft 100, the main shaft sleeve 4 and the rotating assembly due to the difference in the material thermal expansion coefficient, effectively avoiding the risk of structural jamming or the disappearance of the bearing clearance 2. In addition, through the force transmission structure (the driving ring 7 in the following embodiment), the axial stress received by the rotating assembly is transmitted to the dynamic sealing ring 32 and allows it to elastically displace by microns. This ensures that the end face pressure of the sealing pair is always maintained within the optimal range under extreme temperature shocks, avoiding abnormal wear caused by excessive pressure on the sealing surface or leakage caused by separation.

[0048] In some embodiments, a constant-pressure dynamic suppression system is further included for providing and maintaining the isolation liquid in the sealing cavity at a pressure higher than that of the sealed medium.

[0049] In this embodiment, the constant-pressure dynamic suppression system continuously injects the isolation liquid (such as lubricating oil) with a pressure higher than that of the sealed medium into the sealing cavity, forming a stable "pressure wall" on the inside of the dynamic and static ring sealing pair. This makes the sealed medium (insulating medium) always subjected to a net pressure difference pointing to the inside of the device under any working condition, fundamentally eliminating the possibility of medium leakage to the outside, achieving active suppression rather than passive plugging. In addition, the sealing pair will produce normal wear during long-term operation, causing the pre-tightening force to slightly decrease. The constant-pressure dynamic suppression system can monitor and maintain the pressure in the sealing cavity in real time, which is equivalent to continuously and automatically compensating for the sealing force attenuation that may be caused by wear, so that the sealing performance remains stable throughout the life cycle, which is the key to achieving "maintenance-free".

[0050] In some alternative embodiments, the oil can also be manually supplemented, that is, by detecting the pressure of the fluid in the sealing cavity in real time, when it is less than the set threshold, manually supplementing the oil.

[0051] In some embodiments, the bearing 2 is arranged in the sealing cavity, and the two sealing assemblies 3 are arranged one above the other, and the isolation ring 6 is arranged between the upper sealing assembly 3 and the bearing 2.

[0052] In the embodiment of the application, the isolation ring 6 constitutes a physical barrier between the upper sealing assembly 3 and the bearing 2. It can effectively intercept and collect the extremely small amount of metal or ceramic abrasion generated from the normal wear of the dynamic and static ring friction pair of the upper sealing assembly 3, preventing these hard and sharp particles from entering the bearing 2 cavity downward, thereby greatly prolonging the service life of the bearing 2 and ensuring the running accuracy and reliability.

[0053] In addition, the abrasion debris will gradually deposit in the cavity formed by the isolation ring 6. By checking or analyzing the content and morphology of the abrasion debris in the cavity during the maintenance period, the health status and wear rate of the sealing pair can be indirectly evaluated to achieve condition monitoring.

[0054] In some embodiments, the pre-tension comes from a spring 33 built in the body 1. In normal state, the spring 33 is in compression and one end abuts against the side of the static seal ring 31 away from the dynamic seal ring 32.

[0055] In some embodiments, the spring 33 is provided in plurality and is positioned on the body 1.

[0056] In some embodiments, the main shaft sleeve 4 is integrally formed with an annular clamping groove 42 towards the static seal ring 31 at the end close to the medium, one of the dynamic seal rings 32 is arranged in the annular clamping groove 42, and a sealing ring is arranged between the wall surface of the annular clamping groove 42 and the wall surface of the dynamic seal ring 32; the main shaft sleeve 4 is sleeved with the driving ring 7 at the end close to the external atmosphere, and the main shaft sleeve 4 and the driving ring 7 are connected with the main shaft 100 through bolts; one end of the driving ring 7 abuts against the end of the sliding sleeve 5; the driving ring 7 is formed with a limiting portion, and the other dynamic seal ring 32 is sleeved on the driving ring 7 and is limited by the limiting portion from moving axially away from the static seal ring 31.

[0057] In this embodiment, the complex positioning and fixing functions of the dynamic seal ring 32 close to the medium are integrated on one machined part. The dynamic seal ring 32 only needs to be simply embedded in the annular clamping groove 42 to complete accurate positioning, greatly simplifying the assembly process and reducing the dependence on the skills of the operator. At the same time, the integrated design avoids the problem of poor sealing that may be caused by the use of multiple scattered fasteners (such as screws), and in addition, this embodiment can position one side of the system, and the other end of the driving ring 7 abuts against the end of the sliding sleeve 5. When the sliding sleeve 5 generates an axial thrust due to thermal expansion, the thrust directly acts on the driving ring 7 through the abutting surface. Since the driving ring 7 is fixed with the main shaft 100 through bolts, the connection pair allows micron-level elastic deformation or micro-slippage under a huge thrust, and the bearing 2 also drives the body 1 and the static seal ring 31 to axially slide, so that the dynamic seal ring 32 and the static seal ring 31 synchronously slide, avoiding the abnormal pressure between the two caused by the slippage of only one component in the sealing pair.

[0058] In some examples, when the dynamic sealing ring 32 on the atmospheric side is located above the static sealing ring 31, the limiting part is a fixing bolt 71 for fixing the driving ring 7. Specifically, the driving ring 7 is fixed on the main shaft sleeve 4 and the main shaft 100 through a plurality of fixing bolts 71 arranged in sequence along the axial direction, and part of the fixing bolts 71 protrude from the outer wall surface of the driving ring 7. The upper edge of the dynamic sealing ring 32 is provided with a groove, and the fixing bolt 71 is located in the groove, thereby achieving the purpose of limiting the upward movement of the dynamic sealing ring 32.

[0059] In some examples, when the dynamic sealing ring 32 on the atmospheric side is located below the static sealing ring 31, a groove for accommodating the dynamic sealing ring 32 is formed on the driving ring 7, and the bottom surface of the groove is the limiting part.

[0060] In some examples, when the dynamic sealing ring 32 on the medium side is located above the static sealing ring 31, it is necessary to limit the downward movement of the dynamic sealing ring 32 on the medium side. In this example, a circular groove coaxially arranged with the main shaft sleeve 4 is formed on the outer wall of the main shaft sleeve 4 below the dynamic sealing ring 32, and an arc-shaped limiting plate is clamped in the circular groove. The upper surface of the arc-shaped limiting plate abuts against the lower surface of the dynamic sealing ring 32, thereby achieving the purpose of limiting the downward and upward movement of the dynamic sealing ring 32.

[0061] In some examples, the static sealing ring 31 is fixed in the circumferential position relative to the body 1 and can slide axially relative to the body 1 by cooperating with a pin shaft arranged on the body 1. The dynamic sealing ring 32 is fixed in the circumferential position relative to the driving ring 7 or the main shaft sleeve 4 and can slide axially relative to the driving ring 7 or the main shaft sleeve 4 by cooperating with a pin shaft arranged on the driving ring 7 or the main shaft sleeve 4.

[0062] In some embodiments, the constant pressure dynamic suppression system comprises a liquid storage tank 91, a pressure compensator 92, a liquid supplement pump 94, a barrier liquid tank 93, monitoring instruments and a control system; the liquid outlet of the liquid storage tank 91 is connected to the barrier liquid inlet 82 of the sealed cavity through a liquid supply pipeline; the pressure compensator 92 is connected to the liquid storage tank 91 or the liquid supply pipeline, used for pre-charging pressure and maintaining the stability of the basic pressure of the system; the inlet of the liquid supplement pump 94 is communicated with the barrier liquid tank 93, and the outlet is communicated with the liquid storage tank 91; the monitoring instruments include a pressure transmitter, a temperature sensor and a liquid level sensor; the pressure transmitter is arranged on the liquid supply pipeline and / or the liquid storage tank 91, used for real-time detection of the pressure of the barrier liquid; the temperature detection end of the temperature sensor is communicated with the barrier liquid outlet 81 of the sealed cavity, used for real-time detection of the temperature of the barrier liquid in the sealed cavity; the liquid level sensor is arranged in the barrier liquid tank 93, used for real-time monitoring of the liquid level of the barrier liquid; the control system is signal connected with the pressure transmitter, the temperature sensor, the liquid level sensor and the liquid supplement pump 94; the control system is configured to receive the signals of the monitoring instruments and control the operation of the liquid supplement pump 94 according to the signals; when the pressure value detected by the pressure transmitter is lower than a first pressure set value, the control system controls the liquid supplement pump 94 to start and pump the barrier liquid from the barrier liquid tank 93 to the liquid storage tank 91; when the pressure value reaches a second pressure set value higher than the first pressure set value, the control system controls the liquid supplement pump 94 to stop; when the liquid level detected by the liquid level sensor is lower than or higher than the set range, the control system sends an alarm signal.

[0063] In this embodiment, the closed-loop control circuit composed of real-time monitoring by the pressure transmitter, intelligent decision-making by the control system and accurate execution by the liquid supplement pump 94 can maintain the pressure of the barrier liquid in the sealed cavity at a level higher than the pressure of the sealed medium by a stable margin (such as 0.15 MPa) regardless of changes in working conditions and normal wear and tear. This actively establishes and maintains an insurmountable pressure barrier, fundamentally eliminating the leakage of the sealed medium. In addition, this embodiment designs a two-stage pressure maintenance mechanism. Daily pressure fluctuations are instantaneously and non-consumptively absorbed and compensated by the pressure compensator 92 (such as an accumulator); only when the leakage is large enough to cause the pressure to continuously drop to the first set value, the liquid supplement pump 94 is started to consume energy to supplement the pressure. This design greatly reduces the start-stop frequency of the liquid supplement pump 94, saves energy and prolongs the service life of the pump.

[0064] In some embodiments, the body 1 comprises a medium side body 11 and an atmosphere side body 12, both of which are stacked and fixed on the turret housing 200 by the same set of bolts, and a sealing ring is arranged between the medium side body 11 and the abutting surface of the turret housing 200, and between the medium side body 11 and the abutting surface of the atmosphere side body 12.

[0065] The application further provides an electric transmission device for a single-point mooring system, comprising a turret casing 200, a main shaft 100, and the maintenance-free sealing system as described above, the turret casing 200 is filled with a sealed medium, the sealed medium is an insulating medium, the turret casing 200 is provided with a mounting opening penetrating along the thickness direction thereof, and the main shaft 100 penetrates the mounting opening; the maintenance-free sealing system is arranged on the main shaft 100 at the mounting opening and used for sealing the mounting opening.

[0066] Specifically, as shown in Figure 4 The electric transmission in the turret casing 200 is focused on the sealing structure between the main shaft 100 and the turret casing 200, therefore, the structure of the electric transmission in the turret is not embodied in the figure; in the embodiment, the upper part and the lower part of the turret casing 200 need to be sealed, the structures of the two sealing parts are basically the same, the main difference is that the upper and lower structures are reversed, which is because the positions of the medium side and the atmosphere side are reversed, in order to adapt to the positions of the medium side and the atmosphere side, therefore, the structure of the sealing part is also reversed accordingly, in addition, in order to adapt to the reversed structure, some detailed structures are also changed, which can be seen from the structures shown in Figure 5 and Figure 6 .

[0067] The embodiment has all the advantages of the above-mentioned embodiments, which will not be described here.

[0068] The principle and implementation manner of the application are described by using specific examples in the application, the above-mentioned embodiment is only used for helping to understand the method and the core idea of the application; meanwhile, for the general technical personnel in the field, according to the idea of the application, the specific implementation manner and the application range will be changed. In conclusion, the content of the specification should not be understood as the limitation of the application.

Claims

1. A maintenance-free sealing system, characterized by: The utility model provides a sealing assembly of spindle, including main shaft sleeve, body and two sealing assembly, two sealing assembly all include a dynamic seal ring and a static seal ring, the main shaft sleeve is used for the sleeve fixed on the main shaft, the body is used for fixedly arranged on the turret casing, the dynamic seal ring is along the axial direction of main shaft sleeve and can rotate with the main shaft and is sleeved on the main shaft sleeve, one static seal ring corresponds one dynamic seal ring, the static seal ring is arranged on the body and has the freedom of moving along the axial direction, the static seal ring is under the action of preloaded spring and is attached to the end surface of dynamic seal ring and forms the sealing pair, two sealing assembly, main shaft sleeve and body between the structure has a sealing cavity, the sealing cavity is used for preloading isolation liquid, the dynamic seal ring and static seal ring are made of ceramic or hard alloy material, still include bearing and sliding shaft sleeve, the bearing is used for providing the rotation support for main shaft, the bearing is arranged in the sealing cavity, the bearing is located between two sealing assembly, the sliding shaft sleeve can be axially slidably sleeved on the outside of main shaft sleeve, the sliding shaft sleeve is transmission connection with the main shaft sleeve through the key, the sliding shaft sleeve and the inner ring of bearing are fixedly connected by interference fit, the body and the outer ring of bearing are fixedly connected by interference fit, the inner ring of sliding shaft sleeve and bearing is fixedly connected by interference fit, the inner ring of sliding shaft sleeve and bearing forms a rotation assembly, the rotation assembly can slide on the main shaft sleeve along the axial direction, so as to compensate the thermal expansion and contraction amount between the main shaft sleeve and the rotation assembly due to temperature change, the dynamic seal ring in at least one sealing assembly and the rotation assembly between the structure has the force transmission structure and its installation mode allows it to displace axially when subjected to the axial thrust generated by the thermal expansion of the rotation assembly to adapt to the deformation.

2. The maintenance-free sealing system of claim 1, wherein: It also includes a constant pressure dynamic suppression system for providing and maintaining the sealing cavity with isolation liquid higher than the sealed medium pressure.

3. The maintenance-free sealing system of claim 1, wherein: The bearing is arranged in the sealing cavity, and the two sealing assemblies are arranged one above the other, and an isolation ring is arranged between the upper sealing assembly and the bearing.

4. The maintenance-free sealing system of claim 1, wherein: The isolation liquid is lubricating oil.

5. The maintenance-free sealing system of claim 1, wherein: The preloaded spring is built-in in the body, and in normal state, the spring is in compression state and one end abuts against the side of the static seal ring away from the dynamic seal ring.

6. The maintenance-free sealing system of claim 4, wherein: The main shaft sleeve is integrally formed with an annular clamping groove towards the static seal ring at one end close to the medium, one of the dynamic seal rings is arranged in the annular clamping groove, and a sealing ring is arranged between the wall surface of the annular clamping groove and the wall surface of the dynamic seal ring; a driving ring is sleeved on the end of the main shaft sleeve close to the external atmosphere, and the main shaft sleeve and the driving ring are connected with the main shaft through bolts; one end of the driving ring abuts against the end of the sliding shaft sleeve; a limiting portion is formed on the driving ring, and the other dynamic seal ring is sleeved on the driving ring and is limited by the limiting portion from moving axially away from the static seal ring.

7. The maintenance-free sealing system of claim 2, wherein: The constant pressure dynamic inhibition system comprises a liquid storage tank, a pressure compensator, a liquid supplement pump, an isolation liquid tank, monitoring instruments and a control system; a liquid outlet of the liquid storage tank is connected to an isolation liquid inlet of the sealed cavity through a liquid supply pipeline; the pressure compensator is connected to the liquid storage tank or the liquid supply pipeline, used for pre-charging pressure and maintaining the stability of the basic pressure of the system; an inlet of the liquid supplement pump is communicated to the isolation liquid tank, and an outlet thereof is communicated to the liquid storage tank; the monitoring instruments comprise a pressure transmitter, a temperature sensor and a liquid level sensor; the pressure transmitter is arranged on the liquid supply pipeline and / or the liquid storage tank, used for detecting the pressure of the isolation liquid in real time; a temperature detection end of the temperature sensor is communicated to an isolation liquid outlet of the sealed cavity, used for detecting the temperature of the isolation liquid in the sealed cavity in real time; the liquid level sensor is arranged in the isolation liquid tank, used for monitoring the liquid level of the isolation liquid in real time; the control system is signal connected to the pressure transmitter, the temperature sensor, the liquid level sensor and the liquid supplement pump; the control system is configured to receive signals of the monitoring instruments and control the operation of the liquid supplement pump according to the signals; when the pressure value detected by the pressure transmitter is lower than a first pressure setting value, the liquid supplement pump is controlled to be started to pump the isolation liquid from the isolation liquid tank to the liquid storage tank; when the pressure value reaches a second pressure setting value higher than the first pressure setting value, the liquid supplement pump is controlled to be stopped; when the liquid level detected by the liquid level sensor is lower than or higher than a set range, the control system sends an alarm signal.

8. An electrical transmission arrangement for a single point mooring system, characterized in that, The constant pressure dynamic inhibition system comprises a liquid storage tank, a pressure compensator, a liquid supplement pump, an isolation liquid tank, monitoring instruments and a control system; a liquid outlet of the liquid storage tank is connected to an isolation liquid inlet of the sealed cavity through a liquid supply pipeline; the pressure compensator is connected to the liquid storage tank or the liquid supply pipeline, used for pre-charging pressure and maintaining the stability of the basic pressure of the system; an inlet of the liquid supplement pump is communicated to the isolation liquid tank, and an outlet thereof is communicated to the liquid storage tank; the monitoring instruments comprise a pressure transmitter, a temperature sensor and a liquid level sensor; the pressure transmitter is arranged on the liquid supply pipeline and / or the liquid storage tank, used for detecting the pressure of the isolation liquid in real time; a temperature detection end of the temperature sensor is communicated to an isolation liquid outlet of the sealed cavity, used for detecting the temperature of the isolation liquid in the sealed cavity in real time; the liquid level sensor is arranged in the isolation liquid tank, used for monitoring the liquid level of the isolation liquid in real time; the control system is signal connected to the pressure transmitter, the temperature sensor, the liquid level sensor and the liquid supplement pump; the control system is configured to receive signals of the monitoring instruments and control the operation of the liquid supplement pump according to the signals; when the pressure value detected by the pressure transmitter is lower than a first pressure setting value, the liquid supplement pump is controlled to be started to pump the isolation liquid from the isolation liquid tank to the liquid storage tank; when the pressure value reaches a second pressure setting value higher than the first pressure setting value, the liquid supplement pump is controlled to be stopped; when the liquid level detected by the liquid level sensor is lower than or higher than a set range, the control system sends an alarm signal.

Images