Wind turbine lubrication system

Abstract

A wind turbine lubrication system (10) is described. The system (10) comprises a lubricant reservoir (12), a pump (16) for circulating lubricant from the lubricant reservoir (12) to a driveline component (14) of the wind turbine and back to the lubricant reservoir (12). A filter assembly (18) is connected between the lubricant reservoir (12) and the driveline assembly (14). A bypass passage (30) provides a fluid connection between the filter assembly (18) and the lubricant reservoir (12) bypassing the driveline assembly (14). The fluid control device (20) is operable to select between a lubrication circuit and a cleaning circuit. The lubrication circuit includes a lubricant reservoir (12), a filter assembly (18), and a driveline assembly (14). The cleaning circuit does not include a driveline assembly (14) and includes a lubricant reservoir (12), a filter assembly (18), and a bypass passage (30). A method of maintaining a lubrication system (10) includes operating a fluid control device (20) to select a cleaning circuit. The lubricant is then circulated within the cleaning circuit during the cleaning cycle to remove contaminants from the lubricant.

Description

Technical Field

[0001] This invention relates to a lubrication system for a wind turbine and a method for maintaining the lubrication system. Background Technology

[0002] A wind turbine is a machine that converts wind energy into electricity. Like any mechanical system, a wind turbine requires proper lubrication to function optimally. Therefore, a wind turbine includes a lubrication system that distributes lubricating fluid to the drivetrain components, including gearboxes, bearings, shafts, and other rotating or moving parts of the drivetrain.

[0003] The lubrication system includes a pump that distributes lubricant from a reservoir to the drivetrain components via a series of pipes and hoses. Over time, the lubricant will become contaminated with foreign particles, including dust and debris. These particles must be removed from the lubricant, otherwise they may cause excessive wear on the drivetrain components, thus shortening their lifespan, or in extreme cases, potentially damaging the drivetrain components.

[0004] Therefore, lubrication systems include filter assemblies designed to remove contaminants from the lubricant. Filter assemblies typically include replaceable filter elements that capture contaminants and prevent them from circulating within the system and reaching drivetrain components.

[0005] Filter elements are typically replaced at regular maintenance intervals, such as every two years. Before a filter element can be replaced, the pump must be stopped and the filter assembly drained of lubricant. Once the filter assembly has been emptied, the existing filter element is replaced with a new one. The pump is then restarted to resume lubricant circulation through the system.

[0006] The condition of the lubricant can be monitored using sensors or by analyzing samples of the lubricant removed from the system. It has been found that a significant increase in the count of foreign particles in the circulating lubricant has been observed during the initial minutes following filter element replacement. This is believed to be caused by contaminants outside the filter element becoming loose as the filter element is removed. This problem can be exacerbated if the filter assembly is not completely emptied of lubricant before filter element replacement, as these loose contaminants then mix with the lubricant in the filter assembly and are subsequently distributed directly to the drivetrain components after filter maintenance is complete and the pump is restarted.

[0007] One object of the present invention is to provide an improved lubrication system and an improved method for maintaining the lubrication system, which reduces the level of contamination in the lubricant, thereby increasing the service life of the drivetrain components and / or extending maintenance intervals and / or improving the overall efficiency of the wind turbine drivetrain components. Summary of the Invention

[0008] According to a first aspect of the invention, a wind turbine lubrication system is provided, comprising: a lubricant reservoir; a pump for circulating lubricant from the lubricant reservoir to a drivetrain assembly of the wind turbine and back to the lubricant reservoir; a filter assembly connected between the lubricant reservoir and the drivetrain assembly, the filter assembly having an inlet side connected to the lubricant reservoir, an outlet side connected to the drivetrain assembly, and a filter element disposed between the inlet side and the outlet side; and a bypass passage connected between the outlet side of the filter assembly and the lubricant reservoir, wherein the bypass passage provides a fluid connection between the outlet side of the filter assembly and the lubricant reservoir bypassing the drivetrain assembly.

[0009] A bypass channel can be used during a cleaning cycle, in which lubricant (typically oil) circulates through the filter assembly, bypassing the drivetrain components. During routine maintenance of the lubrication system, a cleaning cycle can be run after replacing the filter elements. Therefore, any contaminants in the filter assembly resulting from filter element replacement can be captured by the new filter elements during the cleaning cycle and prevented from being distributed to the drivetrain components. The cleaning cycle can alternatively be run at any other time when lubricant cleaning might be desired. For example, in cases where component failure is unlikely to cause additional contamination in the lubricant, a cleaning cycle can be run to remove any contaminants from the lubricant. This avoids the need to replace the lubricant in cases of excessive contamination.

[0010] The filter assembly may include one or more inlets on the inlet side and one or more outlets on the outlet side. Preferably, the filter assembly includes a single outlet. However, the filter assembly may alternatively include multiple outlets, including a dedicated outlet connected to a bypass channel.

[0011] The first end of the bypass passage is connected to the outlet of the filter assembly. This can be a direct connection to the outlet. Alternatively, it can be an indirect connection. For example, the first end of the bypass passage can be connected anywhere along a conduit that connects the outlet side of the filter assembly to the drivetrain assembly. Preferably, the first end of the bypass passage is connected near the outlet of the filter assembly.

[0012] The second end of the bypass channel is connected to a lubricant reservoir. This can be a direct connection to the reservoir. Alternatively, it can be an indirect connection. For example, the second end of the bypass channel can be connected to a conduit leading to the reservoir. Preferably, the second end of the bypass channel is connected near the inlet of the reservoir.

[0013] The lubrication system preferably includes a fluid control device operable to select between a lubrication circuit and a cleaning circuit. The lubrication circuit is preferably a fluid circuit including a lubricant reservoir, a filter assembly, and a transmission system assembly. The cleaning circuit is preferably a fluid circuit excluding the transmission system assembly and including a lubricant reservoir, a filter assembly, and a bypass passage.

[0014] The lubrication system is preferably configured to circulate lubricant through the lubrication circuit during a lubrication cycle and to circulate lubricant through the cleaning circuit during a cleaning cycle.

[0015] The fluid control device is preferably operable between a first configuration and a second configuration. In the first configuration, the fluid control device allows lubricant to circulate within the lubrication circuit. In the second configuration, the fluid control device allows lubricant to circulate within the cleaning circuit and prevents lubricant from circulating within the lubrication circuit. Preferably, when in the first configuration, the fluid control device also prevents lubricant from circulating within the cleaning circuit. The first and second configurations may alternatively be referred to as a first position and a second position.

[0016] The fluid control device may include one or more valves. Preferably, the fluid control device includes a multi-way valve, more preferably a three-way valve. Preferably, the fluid control device includes a single valve operable between a first position and a second position to select a lubrication circuit or a cleaning circuit. In the first position, the conduit from the outlet side of the filter assembly to the drivetrain assembly can be opened, and the bypass passage can be blocked. In the second position, the conduit from the outlet side of the filter assembly to the drivetrain assembly can be blocked, and the bypass passage can be opened.

[0017] In other examples, the fluid control device may include multiple valves. For example, the fluid control device may include a first valve in a lubrication circuit and a second valve in a cleaning circuit. The first valve preferably controls fluid flow from the outlet side of the filter assembly to the drivetrain assembly. The second valve preferably controls fluid flow through a bypass passage. Lubricant can circulate in the lubrication circuit by opening the first valve, and lubricant can circulate in the cleaning circuit by opening the second valve. Preferably, the fluid control device is configured to close the first valve when the second valve is open to prevent lubricant circulation in the lubrication circuit when a cleaning cycle is selected. The fluid control device may also be configured to close the second valve when the first valve is open, such that the bypass passage is blocked during the lubrication cycle.

[0018] Fluid control devices preferably include ball valves or other suitable valves. Ball valves are preferred because there is essentially no pressure loss on the valve.

[0019] The fluid control device can be operated manually. For example, it can include a valve with a handle that can move between multiple positions. In the first position, a lubrication circuit can be selected. In the second position, a cleaning circuit can be selected.

[0020] The fluid control device may be electrically actuated. Preferably, the fluid control device is an electrically actuated valve, such as a motorized valve. The fluid control device (e.g., one or more valves) may alternatively or additionally be manually operated, for example, by a handle, thereby allowing manual operation when needed.

[0021] Fluid control devices can be remotely operated. For example, they can include remotely controlled electrically actuated valves, such as remotely operated motorized valves.

[0022] The use of remote control valves allows the lubrication system to switch remotely between lubrication and cleaning cycles. This allows the cleaning cycle to be selected without human presence. For example, in cases where a high level of contamination should be detected in the lubricant, the cleaning cycle can be remotely selected to clean the lubricant.

[0023] The filter assembly may include a remotely operable drain valve for discharging lubricant from the filter assembly. The drain valve is preferably connected to a lubricant reservoir, such that lubricant discharged from the filter assembly returns to the lubricant reservoir.

[0024] The use of remotely operable drain valves allows the filter assembly to drain lubricant without the need for a person to be present at the filter, which is typically located inside the nacelle of a wind turbine. For example, a maintenance engineer responsible for replacing filter elements can remotely operate the drain valve to begin draining lubricant as they arrive at the wind turbine or as a lift or ladder is raised to the nacelle. By the time the maintenance engineer arrives at the filter assembly, the lubricant can be substantially or completely drained, allowing for immediate filter element replacement. Typically, draining lubricant from the filter assembly can take fifteen minutes or more, so the ability to remotely open the drain valve can significantly reduce the time required to maintain the lubrication system.

[0025] The bypass passage can be configured to provide a path for air to enter the filter assembly when lubricant is discharged from the filter assembly.

[0026] This allows pressure to balance within the filter assembly during the discharge process, enabling efficient lubricant discharge. A bypass passage provides a convenient route for air to enter the filter assembly.

[0027] The fluid control unit can be remotely operated to select a cleaning circuit while remotely operating the drain valve to drain the filter assembly. Selecting the cleaning circuit allows air to enter the filter assembly during the draining process, enabling the pressure inside the filter assembly to be balanced to facilitate or accelerate lubricant drainage.

[0028] Therefore, maintenance engineers can remotely operate both the drain valve and the fluid control device to select the cleaning circuit before on-site maintenance of the filter assembly, so that the filter assembly is completely emptied and ready for immediate maintenance.

[0029] The pump can be configured to circulate lubricant through the lubrication circuit during a lubrication cycle. The pump is preferably also configured to circulate lubricant through the cleaning circuit during a cleaning cycle. Therefore, the lubrication system may include a single pump. In other examples, the lubrication system may include multiple pumps. For example, the lubrication circuit may include a first pump configured to circulate lubricant during a lubrication cycle, and the cleaning circuit may include a second pump configured to circulate lubricant during a cleaning cycle. The lubrication system may include one or more additional pumps for redundancy or to provide additional pumping capacity when needed.

[0030] According to a second aspect of the invention, a method for maintaining a wind turbine lubrication system of the type described above is provided. The method includes: operating a fluid control device to select a cleaning circuit and circulating lubricant through the cleaning circuit during a cleaning cycle.

[0031] The method preferably includes running a cleaning cycle for several minutes.

[0032] This method may include replacing the filter element with a replacement filter element before starting the cleaning cycle.

[0033] This method may include discharging lubricant from the filter assembly before replacing the filter elements.

[0034] The method may include remotely operating the drain valve of the filter assembly to begin discharging lubricant from the filter assembly.

[0035] This method may include remotely operating the discharge valve before a maintenance engineer reaches the location of the filter assembly (e.g., when the maintenance engineer initially arrives at the wind turbine or boards the wind turbine in the elevator). By the time the maintenance engineer arrives at the filter assembly, the lubricant will have already been discharged from the filter assembly, and the filter elements can be replaced immediately.

[0036] This method may include remotely operating a fluid control device to select a cleaning loop.

[0037] After the cleaning cycle is completed, the method may further include operating a fluid control device to select a lubrication circuit and continuously circulating the lubricant through the lubrication circuit during the lubrication cycle.

[0038] This method may include replacing the pump after a cleaning cycle. For example, in cases where the lubricant is heavily contaminated, such as if a component failure results in a large amount of debris in the lubricant, a cleaning cycle can be run to allow the lubricant to circulate around the drivetrain components through a bypass channel. The pump may optionally be replaced after this process. Replacing the pump is simpler and cheaper than replacing the lubricant in the system. Therefore, the lubricant can be cleaned during routine maintenance of the filter elements and in the event of component failure without requiring a complete lubricant replacement.

[0039] This method may include varying the pump speed during the cleaning cycle. The pump preferably operates at its maximum speed during the cleaning cycle. Operating the pump at high speed and / or at a variable speed generates turbulence during the cleaning cycle, which helps ensure that contaminants within the lubricant are flushed through the cleaning circuit and captured by the filter elements.

[0040] In summary, a wind turbine lubrication system has been described. The system includes a lubricant reservoir, a drivetrain assembly for circulating lubricant from the lubricant reservoir to the wind turbine, and a pump returning the lubricant to the lubricant reservoir. A filter assembly is connected between the lubricant reservoir and the drivetrain assembly. A bypass passage provides a fluid connection between the filter assembly and the lubricant reservoir, bypassing the drivetrain assembly. A fluid control device is operable to select between a lubrication circuit and a cleaning circuit. The lubrication circuit includes the lubricant reservoir, the filter assembly, and the drivetrain assembly. The cleaning circuit does not include the drivetrain assembly and includes the lubricant reservoir, the filter assembly, and the bypass passage. A method of maintaining the lubrication system includes operating the fluid control device to select the cleaning circuit. Lubricant is then circulated within the cleaning circuit during the cleaning cycle to remove contaminants from the lubricant.

[0041] The present invention also provides a wind turbine having the lubrication system described above.

[0042] The preferred and optional features described above regarding the invention as expressed in the system also apply to the invention as expressed in the method, and vice versa. These optional features are avoided entirely for the sake of brevity. Attached Figure Description

[0043] The invention will now be described by way of non-limiting example only with reference to the accompanying drawings, in which: Figure 1 A wind turbine incorporating a lubrication system according to an example of the invention is shown; and Figure 2 This is a simplified piping and instrumentation diagram of a lubrication system according to an embodiment of the present invention. Detailed Implementation

[0044] Figure 1A wind turbine 1 is shown, comprising a tower 2, a nacelle 3 supported at the top of the tower 2, and a rotor 4 mounted to the nacelle 3. The rotor 4 includes a plurality of rotor blades 5 extending radially outward from a central hub 6. The nacelle 3 houses a plurality of components including a generator, which is connected to the rotor 4 via one or more shafts supported by bearings. The wind turbine 1 in this example also includes a gearbox connecting the rotor 4 and the generator. The gearbox is typically connected to the rotor via a low-speed shaft and to the generator via a high-speed shaft. In some wind turbines (so-called "direct-drive" wind turbines), the gearbox is omitted.

[0045] The generator, gearbox (if present), shaft, bearings, etc. together constitute the transmission system of the wind turbine 1.

[0046] refer to Figure 2 The illustration shows a wind turbine lubrication system 10 according to an embodiment of the present invention. The lubrication system 10 is configured to distribute lubricant from a lubricant reservoir 12 to one or more drivetrain components 14 of the wind turbine 1, such as gearboxes, bearings, shafts or other moving parts of the wind turbine drivetrain.

[0047] In addition to the lubricant reservoir 12 Figure 2 The lubrication system 10 shown includes a pump 16, a filter assembly 18, and a fluid control device 20, which are connected by a pump 16, a filter assembly 18, and a fluid control device 20. Figure 2 The arrows in the diagram indicate pipe and / or hose interconnections, and also indicate the direction of lubricant flow within system 10.

[0048] The lubricant reservoir 12 contains a supply of lubricant (e.g., oil). The lubricant reservoir 12 may include a tank sized to hold a large quantity of lubricant. The lubricant reservoir 12 may contain 2,500 liters or more of lubricant.

[0049] Pump 16 is configured to circulate lubricant within lubrication system 10 from reservoir 12 to drivetrain assembly 14 and back to reservoir 12 in a continuous cycle. Pump 16 is preferably capable of pumping 800 liters or more of lubricant per minute around system 10. Thus, under normal use, a full tank of lubricant can circulate through drivetrain assembly 14 approximately every three minutes.

[0050] Although pump 16 is shown connected between reservoir 12 and filter assembly 18 in this example, in other examples, pump 16 may be located in different locations, such as downstream of filter assembly 18. In yet another example, system 10 may include multiple pumps located in different corresponding positions.

[0051] Importantly, any contaminants in the lubricant must be removed before it is supplied to the drivetrain assembly 14. Therefore, a filter assembly 18 is arranged between the lubricant reservoir 12 and the drivetrain assembly 14. The filter assembly 18 includes filter elements 22 that capture and remove contaminants from the lubricant.

[0052] The filter assembly 18 has an inlet side 24 and an outlet side 26. The inlet side 24 is connected to the lubricant reservoir 12, and the outlet side 26 is connected to the drivetrain assembly 14. A filter element 22 is arranged between the inlet side 24 and the outlet side 26. Lubricant from the reservoir 12 enters the filter assembly 18 through an inlet on the inlet side 24 and must pass through the filter element 22 before leaving the filter assembly 18 through an outlet on the outlet side 26. As the lubricant passes through the filter assembly 18, any contaminants in the lubricant are removed by the filter element 22.

[0053] A fluid control device 20 is disposed within a conduit 28 that connects the outlet side 26 of the filter assembly 18 to the transmission assembly 14. Alternatively, the fluid control device 20 may be directly attached to the outlet of the filter assembly 18. The fluid control device 20 is operable to control the flow of lubricant within the lubrication system 10, as will be discussed in more detail below.

[0054] The lubrication system 10 includes a bypass passage 30. The bypass passage 30 provides a fluid connection between the outlet side 26 of the filter assembly 18 and the lubricant reservoir 12, bypassing the drivetrain assembly 14. In this example, a first end 32 of the bypass passage 30 is connected to a fluid control device 20. A second end 34 of the bypass passage 30 is connected directly to the lubricant reservoir 12, either directly or via a conduit extending to the lubricant reservoir 12. Preferably, the bypass passage 30 provides a direct connection between the filter assembly 18 and the reservoir 12, i.e., a direct return path for lubricant to leave the filter assembly 18 and return to the reservoir 12.

[0055] The fluid control device 20 is operable to select between a lubrication circuit and a cleaning circuit. The lubrication circuit is a fluid circuit including a lubricant reservoir 12, a filter assembly 18, and a drivetrain assembly 14. The cleaning circuit is a fluid circuit including a lubricant reservoir 12, a filter assembly 18, and a bypass passage 30. The cleaning circuit does not include the drivetrain assembly 14; that is, it bypasses the drivetrain assembly 14.

[0056] In this example, the fluid control device 20 includes a three-way valve. Preferably, the fluid control device 20 is a three-way ball valve.

[0057] In the first position, valve 20 provides a fluid communication passage between filter assembly 18 and drivetrain assembly 14 while blocking bypass passage 30. Therefore, when pump 16 is operating with valve 20 in its first position, lubricant circulates in the lubrication circuit from reservoir 12 through filter assembly 18 to drivetrain assembly 14 and then back to reservoir 12.

[0058] In the second position, valve 20 opens the bypass passage 30 while simultaneously blocking the passage of lubricant from filter assembly 18 to drivetrain assembly 14. Therefore, when pump 16 operates with valve 20 in its second position, lubricant circulates from reservoir 12 through filter assembly 18 in the cleaning circuit and returns to reservoir 12 via bypass passage 30, thus bypassing drivetrain assembly 14.

[0059] It is necessary to replace the filter element 22 in the filter assembly 18 at regular intervals, such as every two years. Before replacing the filter element 22, the wind turbine is stopped and the pump 16 in the lubrication system 10 is turned off to prevent lubricant from circulating within the system 10. The lubricant in the filter assembly 18 is then completely drained by opening the drain valve 36 in the conduit 38 that connects the filter assembly 18 to the reservoir 12. Once all lubricant has been drained from the filter assembly 18, the filter element 22 can be removed and replaced with a new filter element. The pump 16 can be reactivated to restore lubricant circulation within the system 10.

[0060] The process of changing filter element 22 can lead to increased contamination in the lubricant. This may be due to contaminants being shed from the old filter element 22 when it is removed. In fact, it has been found that the contamination level in system 10 can increase significantly during the first few minutes after replacing filter element 22.

[0061] In conventional lubrication systems that do not include bypass channel 30, when pump 16 is reactivated after filter element replacement, these contaminants may be directly distributed to drivetrain components 14. This could damage sensitive components in the drivetrain or cause excessive wear, thereby shortening the service life of these components.

[0062] With this invention, these contaminants can be removed from the lubricant during a cleaning cycle initiated after the filter element 22 has been replaced. Therefore, before removing the filter element 22, the flow control device is positioned in a second position to open the bypass passage 30 and block the line connecting the filter assembly 18 to the drivetrain assembly 14. When the pump 16 is reactivated after replacing the filter element 22, the lubricant circulates in a cleaning loop that bypasses the drivetrain assembly 14. Specifically, the lubricant circulates from the reservoir 12, through the filter assembly 18 with its new filter element 22, and returns to the reservoir 12 via the bypass passage 30.

[0063] The cleaning cycle can run for several minutes, allowing virtually all the lubricant in system 10 to circulate multiple times through the new filter element 22. This process very effectively removes a significant amount (if not all) of the contaminants from the lubricant after the filter is replaced and before the lubricant is distributed to the drivetrain assembly 14.

[0064] At the end of the cleaning cycle, the fluid control device 20 moves to its first position, which blocks the bypass passage 30 and opens the line connecting the filter assembly 18 to the drivetrain assembly 14. The cleaned lubricant then circulates within the lubricant circuit and through the drivetrain assembly 14, and the wind turbine can be restarted.

[0065] Besides being used immediately after replacing filter elements, the cleaning cycle can also be advantageously used at any other time to clean the lubricant. For example, in cases of high contamination levels in the lubricant for any reason, the cleaning cycle can be activated to provide additional filtration of the lubricant. High levels of contamination can occur if components are excessively worn or completely failed.

[0066] In the very rare event of component failure, a large amount of metal particles or other debris can contaminate the lubricant. Typically, this necessitates shutting down the wind turbine and replacing the lubricant. Lubricant replacement is a daunting task, given the large amount of lubricant that must be drained, disposed of, and replaced from system 10. This process is further complicated because the lubrication system 10 is typically located within the wind turbine nacelle 3, which may be situated atop a very high tower 2, and in the case of offshore turbines, at sea.

[0067] This invention eliminates the need for lubricant replacement. Instead, existing lubricant can be cleaned by activating a cleaning cycle to remove all harmful contaminants. The drivetrain components 14 are protected during this process as they are bypassed. After lubricant cleaning, filter element 22 can be replaced. Furthermore, if damage occurs during the cleaning process, pump 16 may need to be replaced. However, replacing pump 16 is a relatively simple and inexpensive operation compared to replacing all lubricant. Therefore, any downtime of the wind turbine can be significantly reduced. Thus, the ability to clean lubricant in this manner offers significant benefits in terms of efficiency and cost savings.

[0068] In a particularly advantageous configuration, the flow control device can be remotely operated; for example, it can include a remotely controlled electrically actuated valve. This advantageously allows activation of the cleaning cycle even if a maintenance engineer is not required to be present at the wind turbine. For example, system 10 can include sensors for determining the level of contamination in the lubricant and can activate the cleaning cycle to provide additional filtration of the lubricant if the contamination level exceeds a certain level.

[0069] System 10 can be configured to generate turbulence within the filter assembly during cleaning cycles to help flush away contaminants. For example, pump 16 can be configured to operate at a higher speed than normal during cleaning cycles. Alternatively or additionally, pump 16 can be configured to operate at a variable speed during cleaning cycles. Both options increase lubricant turbulence and improve the efficiency of the filtration process.

[0070] In a particularly advantageous configuration, the drain valve 36 can be remotely operated, for example, it can be a remotely controlled electro-actuated valve. This allows the filter assembly 18 to drain lubricant without requiring on-site maintenance at the filter assembly 18. For example, it would allow a maintenance engineer to prepare the filter assembly 18 for filter replacement before reaching the wind turbine or while the maintenance engineer is climbing the turbine tower 2 via ladder or lift. Since draining lubricant is relatively time-consuming, the ability to drain lubricant before reaching the filter assembly 18 has significant benefits and reduces the time required for maintenance of the system 10.

[0071] The bypass duct 30 can be configured to allow air into the filter assembly 18 when the flow control is set to the second position (i.e., when the cleaning circuit is selected). When the filter assembly 18 discharges lubricant, air can then enter the filter assembly 18 via the bypass duct 30, allowing pressure to be equalized within the filter assembly 18 and allowing lubricant to escape through the discharge valve 36. The bypass duct 30 can be sized to accommodate a sufficient volume of air, or may include a vent to facilitate the process.

[0072] The combination of the remotely operable fluid control device 20 and the remotely operable drain valve 36 is particularly advantageous. This allows maintenance engineers to operate both valves remotely, enabling lubricant to be effectively discharged from the filter assembly 18, while air is allowed to enter the filter assembly 18 through the bypass passage 30.

[0073] As can be understood from the above description, the present invention presents many advantages over prior art lubrication systems. Specifically, through the bypass channel 30 and the cleaning cycle, foreign particles trapped in system 10 during filter removal are captured in a new filter, rather than being directly distributed to the gearbox or other drivetrain components 14. This avoids foreign particles downstream of the filter. This results in a contaminated lubricant, which will increase the life of the gearbox and other drivetrain components 14 and prevent excessive wear or failure of components. System 10 can also extend maintenance intervals and improve the efficiency of the wind turbine drivetrain components 14 because it allows for cleaning of the lubricant as needed to remove contaminants that might otherwise damage the drivetrain components 14.

[0074] Many modifications can be made to the above examples without departing from the scope of the invention as defined in the appended claims. Many such modifications and variations have been described in the "Summary of the Invention" section above.

Claims

1. A wind turbine lubrication system, comprising: Lubricant reservoir; A pump for circulating lubricant from the lubricant reservoir to the drivetrain components of the wind turbine and back to the lubricant reservoir; A filter assembly connecting the lubricant reservoir and the transmission assembly, the filter assembly having an inlet side connected to the lubricant reservoir, an outlet side connected to the transmission assembly, and a filter element disposed between the inlet side and the outlet side; as well as A bypass channel connects the outlet side of the filter assembly to the lubricant reservoir, wherein the bypass channel provides a fluid connection between the outlet side of the filter assembly and the lubricant reservoir, bypassing the drivetrain assembly.

2. The wind turbine lubrication system according to claim 1 further includes a fluid control device operable to select between a lubrication circuit and a cleaning circuit, wherein... The lubrication circuit is a fluid circuit that includes the lubricant reservoir, the filter assembly, and the drivetrain assembly, and the cleaning circuit is a fluid circuit that does not include the drivetrain assembly but includes the lubricant reservoir, the filter assembly, and the bypass passage.

3. The wind turbine lubrication system according to claim 1 or claim 2, wherein, The pump is configured to circulate lubricant through the lubrication circuit during a lubrication cycle and through the cleaning circuit during a cleaning cycle.

4. The wind turbine lubrication system according to any of the preceding claims, wherein, The fluid control device includes one or more valves, and preferably includes a multi-way valve such as a three-way valve.

5. The wind turbine lubrication system according to any of the preceding claims, wherein, The fluid control device is electrically actuated.

6. The wind turbine lubrication system according to any one of the preceding claims, wherein, The fluid control device can be operated remotely.

7. The wind turbine lubrication system according to any one of the preceding claims, wherein, The filter assembly also includes a remotely operable drain valve for discharging lubricant from the filter assembly.

8. The wind turbine lubrication system according to any of the preceding claims, wherein, The bypass channel is configured to provide a passage for air to enter the filter assembly when lubricant is discharged from the filter assembly.

9. A method for maintaining a wind turbine lubrication system according to claim 2, the method comprising operating the fluid control device to select the cleaning circuit and circulating lubricant through the cleaning circuit during a cleaning cycle.

10. The method of claim 9, further comprising replacing the filter element with a replacement filter element before starting the cleaning cycle.

11. The method of claim 10, further comprising discharging lubricant from the filter assembly before replacing the filter element.

12. The method of claim 11, further comprising remotely operating a drain valve of the filter assembly to begin discharging lubricant from the filter assembly.

13. The method according to any one of claims 9 to 12, further comprising remotely operating the fluid control device to select the cleaning circuit.

14. The method according to any one of claims 9 to 13, wherein, After the cleaning cycle is completed, the method further includes operating the fluid control device to select the lubrication circuit and continuously circulating the lubricant through the lubrication circuit during the lubrication cycle.

15. The method according to any one of claims 9 to 14, further comprising replacing the pump after the cleaning cycle.

16. The method according to any one of claims 9 to 14, further comprising changing the speed of the pump during the cleaning cycle.

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