Wind turbine generator grease extraction device and method of grease extraction

Abstract

The present invention provides an oil extraction device for extracting oil from an oil accumulation region (4) of a wind turbine generator (1). A suction conduit (11) having an inlet (12) is provided for positioning at the oil accumulation region (4). A collection chamber (10) is connected to the suction conduit (11) for collecting oil drawn in through the suction conduit (11). A vacuum pump (7) is used to generate a negative pressure in the suction conduit (11) to draw the oil into the collection chamber (10) through the inlet (12).

Description

[Technical Field]

[0001] This invention relates to a wind turbine generator grease extraction device and related methods. [Previous Technology]

[0002] In this application, the term "wind turbine generator" is used to refer to the generator itself and the associated drive train. Conversely, the term "wind turbine" is used to refer to the entire wind turbine assembly, including the tower, blades, nacelle, and generator. However, in this art, the terms "wind turbine generator" and "wind turbine" are sometimes used interchangeably depending on the context.

[0003] Wind turbines present a unique set of challenges in maintenance and repair. In particular, they are typically located offshore or in other remote locations, with the generators mounted in elevated positions within nacelles atop towers, making them difficult to access. Therefore, maintenance and repair operations are both expensive and dangerous, requiring specialized vehicles and equipment. Furthermore, wind turbine generators are particularly prone to failure. That said, other generator applications typically operate under relatively stable conditions and relatively controlled environmental conditions. This provides a degree of predictability in terms of operational durability, thus allowing maintenance intervals to be scheduled to identify defects before they lead to catastrophic failures. In contrast, wind turbine generators are subjected to enormous load variations with changes in wind speed and direction, as well as significant variations in thermal stress due to changes in weather conditions. These variations often accelerate certain failure modes in unpredictable ways, meaning that preventing problems through regular maintenance is extremely challenging. Therefore, not only is the maintenance of wind turbine generators more expensive and challenging, but predicting when maintenance is needed is also more difficult.

[0004] Specific problems arise related to the interacting surfaces within a wind turbine generator, such as bearing surfaces, gears, and other components of the transmission system. To provide lubrication and reduce wear, it is necessary to supply lubricating grease to these components. However, over time, the grease can become contaminated with contaminants and wear debris, thus requiring the removal of this "used" grease from the circulation.

[0005] In this regard, Figure 1 shows a schematic diagram of a conventional grease extraction device connected to the bearing component 1 of a wind turbine generator. In this arrangement, a grease collection reservoir 3 is connected to the lubricated mechanical component via a delivery pipe 2. The grease collection reservoir 3 is typically located at the base of the machine housing, and the delivery pipe 3 is connected to a raised area of ​​the mechanical component to allow grease to be fed downwards from this extraction location into the collection reservoir 3 by gravity. However, this arrangement is known to have disadvantages. Most notably, some used grease will not be collected at the inlet of the delivery pipe 3 at the extraction location, but will instead accumulate in an accumulation area 4 at the base of the machine. This can happen, for example, due to leaks between components or if the delivery pipe 2 or reservoir 3 overflows. As this collected grease accumulates over time, it eventually requires manual extraction by cleaning personnel. This becomes a very expensive and arduous task, as the mechanical components of the generator and transmission housing need to be offline and then opened to allow actual access to their interior. Furthermore, if this operation is not completed quickly enough, grease exposure and subsequent leaks can damage other components of the generator. For example, if grease leaks into the retainer, it can cause the retainer slot to become clogged, potentially leading to the failure of a major component. This will then require extensive and therefore expensive repairs.

[0006] The aforementioned drawbacks are not easily resolved. For example, conventional extraction devices cannot supply grease from the accumulation area 4 at the base of the mechanism because gravity requires the reservoir 3 to be below the inlet of the delivery pipe 2. Furthermore, the high viscosity of the grease and its slow, intermittent accumulation over a long period mean that conventional pump systems are also unsuitable. Some other proposed solutions include providing several smaller, independent reservoirs integrated into the generator itself for collecting grease at different locations. However, while these arrangements may allow for better grease capture, periodically emptying the smaller reservoirs would be time-consuming, and such solutions would require costly modifications to the generator itself.

[0007] Therefore, the present invention seeks to solve the above-mentioned problems. [Summary of the Invention]

[0008] According to a first aspect of the present invention, an oil extraction device is provided for extracting oil from an oil accumulation area of ​​a wind turbine generator, comprising: a suction conduit having an inlet for positioning at the oil accumulation area; a collection chamber connected to the suction conduit for collecting oil sucked in through the suction conduit; and a vacuum pump for generating a negative pressure in the suction conduit to draw oil into the collection chamber through the inlet.

[0009] In this manner, a vacuum pump can be used to draw air from the collection chamber to create a partial vacuum, which in turn creates negative pressure in the suction duct to draw in grease. That is, the pressure inside the suction duct is reduced relative to the surrounding atmospheric pressure. This creates a suction effect at the inlet, transporting the grease through the suction duct to the collection chamber to balance the decompression created by the vacuum pump. When high thrust is achieved, grease can be efficiently extracted from any extraction location without raising that location relative to the collection chamber. Furthermore, high thrust allows extraction over relatively long distances, allowing the collection chamber and vacuum pump to be located outside the wind turbine housing. This allows for the use of a larger collection chamber, thereby minimizing the frequency of venting that may be required. Additionally, the suction effect allows for the use of smaller diameter ducts. For example, in embodiments where a duct is used as the suction duct, a smaller diameter duct can be connected to the wind turbine housing compared to a conventional gravity-driven arrangement. This allows for easier implementation of the system without disrupting service mechanisms. Advantageously, this arrangement also allows for the use of an inexpensive air pump, rather than pumping the viscous grease itself directly. Therefore, implementation can thus be both cost-effective and flexible. In addition, directly pumping grease would require a pump with higher pressure, which in turn would increase the risk of related pump conduit rupture, posing a safety hazard and requiring continuous lubrication within the pump mechanism itself.

[0010] In an embodiment, the collection chamber includes a vacuum port and a suction port, wherein a vacuum pump is connected to the vacuum port to generate negative pressure in the collection chamber, and wherein a suction conduit is connected to the suction port. In this way, the collection chamber can be provided as a simple, sealed volume with independent ports for easy connection to the suction conduit and the vacuum pump.

[0011] In an embodiment, the vacuum port is located in the upper region of the collection chamber for drawing air from the collection chamber. In this way, air can be drawn out from the upper region inside the collection chamber, while the port inlet is separated from the collected grease at the bottom of the collection chamber, thereby reducing the risk of it being drawn into the vacuum pump.

[0012] In an embodiment, the suction port includes a delivery tube that extends into the collection chamber below the inlet of the vacuum port. In this way, grease can be delivered into the collection chamber while reducing the chance of grease being guided onto the chamber walls. Furthermore, this arrangement also serves as a stopping mechanism to prevent further grease extraction once the grease level reaches the bottom of the delivery tube, as the partial vacuum in the remaining part of the collection chamber is no longer sufficient to generate sufficient negative pressure within the suction tube.

[0013] In an embodiment, the device further includes a one-way valve connected between the collection chamber and the vacuum pump for maintaining the negative pressure generated by the vacuum pump in the collection chamber. Thus, the one-way valve prevents air from being drawn back into the collection chamber via the vacuum pump. Therefore, the negative pressure in the collection chamber is essentially balanced only by drawing fluid into the suction conduit. That is, the one-way valve maintains the negative pressure generated by the vacuum pump, thereby allowing grease to be drawn into the collection chamber even after the vacuum pump has been stopped. Therefore, continuous operation of the vacuum pump is not required to maintain grease extraction.

[0014] In an embodiment, the device further includes a release valve for releasing negative pressure in the collection chamber. This allows for rapid cessation of grease extraction by balancing the pressure in the collection chamber, and also allows the collection chamber to be emptied.

[0015] In an embodiment, the collection chamber can be configured to fit into an existing slot within a wind turbine generator. In an embodiment, the collection chamber includes a fixed cover. In an embodiment, a tri-clamp connector can be used to install the collection chamber. This arrangement facilitates easy disassembly. In an embodiment, a dedicated port can be provided for connecting a pressure gauge and a relief valve.

[0016] In an embodiment, the device further includes a controller for controlling a vacuum pump, wherein the controller is configured to periodically initiate an extraction operation, wherein the vacuum pump generates negative pressure to extract grease from areas of grease buildup. In this way, the vacuum pump can operate intermittently, for example at predetermined time intervals, to minimize wear on its components and increase its service life.

[0017] In an embodiment, the extraction operation includes cyclically starting the vacuum pump. In this way, the vacuum pump can be cyclically turned on and off to minimize wear on its components and increase its service life.

[0018] In an embodiment, each cycle includes starting the vacuum pump until a peak negative pressure is generated, and then stopping it for a downtime period. Therefore, this can explain the relatively slow fluid flow associated with highly viscous greases by generating a peak negative pressure during startup and allowing the pump to be stopped while the grease is slowly drawn into the collection chamber to balance the negative pressure.

[0019] In an embodiment, the downtime is configured such that the negative pressure in the suction catheter does not drop below the threshold pressure required for grease to be drawn through the inlet. In this way, the negative pressure can be maintained high enough to draw grease through the suction catheter throughout the extraction operation without requiring continuous operation of the vacuum pump. In an embodiment, the downtime can be a predetermined period of time selected based on system specifications, such as the viscosity of the grease, the length and diameter of the suction catheter, and the peak negative pressure generated in the collection chamber.

[0020] In this embodiment, the controller initiates the extraction operation on a cycle of 1-365 days. In this way, the frequency of the extraction operation can be set according to the needs of the application, thereby minimizing operation time while ensuring that a sufficient volume of grease is removed. For example, performing an extraction operation once every 7 days may be sufficient to avoid grease buildup while maximizing the pump's lifespan.

[0021] In an embodiment, each extraction operation comprises 3-10 cycles. In this way, the number of cycles can be set to ensure that a sufficient volume of grease is removed, depending on the frequency of the extraction operation.

[0022] In an embodiment, each cycle has a duration of 10-20 minutes. In this way, the suction effect can be maintained for an extended period. For example, in an embodiment, the controller can perform a 15-minute cycle, wherein the vacuum pump is activated for 3 minutes to reach peak negative pressure, followed by a 12-minute shutdown cycle.

[0023] In an embodiment, the grease accumulation area is the housing area below the bearing within the wind turbine generator, wherein the device further includes a mounting for installing an inlet in the housing area below the bearing. Thus, a wind turbine grease extraction device is provided, capable of extracting used grease from a wind turbine generator. Therefore, this allows for easy and efficient grease extraction, minimizing the need for maintenance operations to remove grease spills, thereby significantly saving costs in the wind turbine field.

[0024] In an embodiment, the suction catheter is a tube with an orifice diameter of 5 mm to 60 mm. A preferred orifice diameter is 15-40 mm, and an optimal orifice diameter is 30-35 mm. In this way, grease can be extracted from the machine using a compact and flexible catheter. Therefore, this allows the device to be implemented in a variety of applications.

[0025] According to the second embodiment, a method for extracting grease from a grease accumulation area of ​​a wind turbine generator is provided, comprising: positioning the inlet of a suction conduit at the grease accumulation area; using a vacuum pump to generate negative pressure in the suction conduit to draw in grease through the inlet; and collecting the grease drawn in through the suction conduit in a collection chamber connected to the suction conduit.

[0026] In an embodiment, the step of generating negative pressure in the inhalation duct includes using a controller to control the vacuum pump to periodically initiate an extraction operation, in which the vacuum pump generates negative pressure. [Simplified Explanation of the Diagram]

[0027] Illustrative embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0027] Figure 1 shows a schematic diagram of a conventional grease extraction device connected to a bearing component of a wind turbine generator;

[0027] FIG2 shows a schematic diagram of an oil extraction device according to an exemplary embodiment, the oil extraction device being connected to a bearing component of a wind turbine generator; and

[0027] Figure 3 shows a graph of negative pressure over time for the extraction operation performed by the illustrative embodiment.

Implementation Method

[0028] Figure 2 shows an grease extraction device 100 according to an illustrative embodiment. The grease extraction device is assembled into a bearing component 1 of a wind turbine generator. For simplicity, other components of the wind turbine and wind turbine generator are not shown.

[0029] The device 100 includes a suction pipe 13, the inlet end 14 of which is installed at the accumulation area 4 of the bearing component 1, and the other end is connected to the suction port 5 of the collection chamber 11. The suction port 5 is connected to an inlet delivery pipe 12, which extends downward to the top of the collection chamber 11 for delivering grease into the collection chamber 11. The collection chamber 11 is a sealed container with a fixed volume, such that the pressure inside the collection chamber 11 can vary relative to atmospheric pressure. The collection chamber 11 has a removable cover for emptying the container.

[0030] A vacuum pump 8 is further provided for drawing air from the collection chamber 11 through the vacuum tube 7. The vacuum pump 8 is a dry air pump that expels air, thereby drawing airflow through the vacuum tube 7. The vacuum tube 7 is connected to the collection chamber 11 at a vacuum port 10 at the top of the collection chamber 11. Therefore, the inlet of the vacuum port 10 is higher than the inlet of the delivery tube 12. The vacuum pump 8 is controlled by a controller 9, which includes a timer for periodically starting the vacuum pump to evacuate air from the collection chamber 11.

[0031] A one-way valve 6 is disposed in the vacuum tube 7 between the vacuum pump 8 and the collection chamber 11. The one-way valve 6 is oriented to allow air to be drawn out of the collection chamber 11 through the vacuum pump 8. At the same time, the one-way valve 6 prevents air from being drawn back into the collection chamber through the vacuum tube 7. It should be understood that although the one-way valve 6 is shown separately, it can be integrated into the vacuum port 10 or the vacuum pump 8.

[0032] In this embodiment, the release valve 15 is incorporated into the collection chamber 11 to release a portion of the vacuum by allowing air to flow into the collection chamber 11. This allows for rapid equalization of the partial vacuum within the collection chamber 11 if needed. The release valve 15 is further provided with a filter covering its inlet to prevent actual damage in the event of accessory blockage of the inlet.

[0033] In this embodiment, the suction pipe 12 is formed from a 5-meter-long pipe with a 22mm hole, extending through the machine housing surrounding the bearing 1. This allows the collection chamber 11, vacuum pump 8, and controller 9 to be located outside the wind turbine generator, thus providing simplified installation.

[0034] During the extraction operation, the controller 9 activates the vacuum pump 8, which draws air through the vacuum tube 7 and the one-way valve 6 to reduce the pressure inside the collection chamber 11. This establishes a negative pressure, where the pressure inside the collection chamber 11 is lower than atmospheric pressure. Therefore, this negative pressure draws fluid through the suction tube 13. Since the inlet 14 of the suction tube 13 is located in the accumulation area 4 of the machine collecting used grease, the grease is drawn into the collection chamber 11 through this inlet 14 and the suction tube 13. Thus, the used grease is extracted from the bearing 1.

[0035] In use, the oil extraction device 100 operates periodically to perform extraction operations at predetermined time intervals. In this embodiment, the controller 9 is configured to perform a weekly extraction operation, although other time periods may be used, depending on, for example, the oil collection rate at the accumulation region 4. In other embodiments, a sensor may be provided in the oil collection region 4 to trigger the controller 9 to start the extraction operation by activating the pump 8.

[0036] Figure 3 shows a graph of the negative pressure 16 changing over time during a single extraction operation. At the start of the extraction operation sequence, the controller 9 activates the vacuum pump 8 to generate a negative pressure in the collection chamber 11.

[0037] There is a minimum threshold pressure 18 at which the propulsive suction generated by the partial vacuum within the collection chamber 11 is sufficiently high to draw in grease through the suction tube 13. In the example shown in Figure 3, the threshold pressure 18 is approximately -0.6 bar or -60 kPa based on a 5-meter suction tube 12 with a 22 mm diameter orifice, and the grease is Monbilith SHC007 (RTM). However, it should be understood that the level of the minimum threshold pressure depends on several factors, including the viscosity of the extracted grease, the amount of contaminants, and the diameter and length of the suction tube 13.

[0038] As the negative pressure in the collection chamber 11 increases above the minimum threshold pressure 18, the grease is drawn into the collection chamber 11 through the suction tube 13. In this embodiment, the vacuum pump 8 is capable of generating a peak negative pressure 17 slightly below 1 bar, around -0.95 bar or -95 kPa, and depending on the pump 9 and the size of the collection chamber, it takes approximately 2 minutes for the collection chamber 11 to naturally reach this negative pressure.

[0039] Once the peak negative pressure 17 is reached, continued operation of the vacuum pump 8 will not further increase the negative pressure. After a fixed time period (two minutes in this case), the controller 9 deactivates the vacuum pump 8. However, since the one-way valve 6 prevents air from flowing in through the vacuum port 10, the negative pressure in the collection chamber 11 can only be essentially balanced by the grease flowing in through the suction pipe 13. Therefore, as shown in Figure 3, the negative pressure is maintained at a relatively high level by the one-way valve 6, and gradually decreases due to the relatively slow flow rate of the grease entering the collection chamber 11.

[0040] Controller 9 keeps the vacuum pump off for a predetermined duration, in this case 15 minutes. During this shutdown period, the negative pressure 16 slowly decreases until it reaches a lower negative pressure level 18. The duration of the shutdown period is selected to ensure that the lower negative pressure level 18 remains above the minimum threshold pressure 19, thereby maintaining the movement of grease into the collection chamber 11. This completes the first vacuum cycle 20.

[0041] After the first vacuum cycle 20, the process can be repeated in the second vacuum cycle 21, during which the vacuum pump 8 runs for a 1-minute start-up period, during which the peak negative pressure 17 is reached, followed by a 15-minute shutdown period. This operation can then be repeated as needed for further cycles.

[0042] In this example, a sequence of five vacuum cycles was used. That is, there is a 2-minute start-up period, followed by a 15-minute stop-down period, and then four cycles with 1-minute start-up periods followed by 15-minute stop-down periods. Thus, each extraction operation maintains the negative pressure above the minimum threshold pressure 19 for approximately 85 minutes, which was able to extract approximately 2000g of grease during the testing period of the illustrative example. However, the vacuum pump 8 itself only ran for a total of 6 minutes. Over a year, through weekly scheduled extraction operations, a total of 104 kg of grease could be removed, with a total vacuum pump running time of 312 minutes.

[0043] During maintenance operations, the collection chamber 11 can be periodically emptied of grease. For example, during an inspection visit, a technician can trigger a release to equalize the pressure in the collection chamber 11 and then gently pour out the contents to be removed from the wind turbine. Alternatively, a plastic bag can be used as a liner in the collection chamber 11, or the entire collection chamber 11 can be replaced with a new one.

[0044] Importantly, for the aforementioned device, because its operating time is shortened and the negative pressure required for effective operation is relatively low, a relatively inexpensive vacuum pump 8 can be used. Therefore, there is no need to use a more expensive vacuum pump capable of continuous operation. Furthermore, the relatively low vacuum is much safer than a pressurized system. Therefore, a safe, cost-effective, and flexible grease extraction device can be provided. This avoids the need to schedule time-consuming and expensive manual grease cleaning services. At the same time, it reduces the risk of damage from grease buildup.

[0045] Furthermore, the extraction device can be used in conjunction with existing oil extraction devices (such as gravity systems) or as a replacement for those traditional devices. Therefore, a simplified oil extraction solution can be provided.

[0046] It should be understood that the embodiments described above are for illustrative purposes only to show the application of the invention. In practice, the invention can be applied to many different configurations, and detailed embodiments will be readily apparent to those skilled in the art.

[0047] For example, although a simple timer controller has been described in the illustrative embodiments above, it should be understood that more advanced control and monitoring functions can be incorporated. For example, the controller can provide feedback to the SCADA system or otherwise provide remote alarms on the system status.

[0048] It should also be understood that the location of the accumulation area may vary depending on the machine, and in some cases, the machine may have multiple grease accumulation areas. In this case, more than one extraction device may be used, or multiple tubes 13 may be connected to the collection chamber 11. Here, the tubes 13 may be distributed throughout the collection chamber 11 to avoid the accumulation of thick grease or the separation of grease into soap and oil.

Claims

1. A grease extraction device for extracting leaked grease from a leaked grease accumulation area at the base of a wind turbine generator housing, comprising: The suction catheter has an inlet for positioning at the area where the leaked grease has accumulated. A collection chamber, connected to the suction conduit, for collecting leaked grease sucked in through the suction conduit; and a vacuum pump for generating negative pressure in the suction conduit to draw the leaked grease into the collection chamber through the inlet.

2. The oil extraction apparatus as described in claim 1, wherein, The collection chamber includes a vacuum port and a suction port, wherein the vacuum pump is connected to the vacuum port to generate negative pressure in the collection chamber, and wherein the suction conduit is connected to the suction port.

3. The oil extraction apparatus as described in claim 2, wherein, The vacuum port is located in the upper region of the collection chamber and is used to draw air from the collection chamber.

4. The oil extraction apparatus as described in claim 2 or 3, wherein, The suction port includes a delivery tube that extends into the collection chamber to a position below the inlet of the vacuum port.

5. The oil extraction apparatus as claimed in claim 1, further comprising a one-way valve connected between the collection chamber and the vacuum pump for maintaining the negative pressure generated in the collection chamber by the vacuum pump.

6. The oil extraction apparatus as claimed in claim 1, further comprising a controller for controlling the vacuum pump, wherein, The controller is configured to periodically initiate an extraction operation in which the vacuum pump generates negative pressure to extract the leaking grease from the area where the grease has accumulated.

7. The oil extraction apparatus as described in claim 6, wherein, The extraction operation involves cyclically starting the vacuum pump.

8. The oil extraction apparatus as described in claim 7, wherein, Each cycle involves starting the vacuum pump until a peak negative pressure is generated, and then stopping it for a period of downtime.

9. The oil extraction apparatus as described in claim 8, wherein, The shutdown period is configured to prevent the negative pressure in the inhalation catheter from dropping below the threshold pressure required to inhale leaked grease through the inlet.

10. The oil extraction apparatus as described in claim 6, wherein, The controller initiates the extraction operation every 1-365 days.

11. The oil extraction apparatus as described in claim 7, wherein, Each extraction operation consists of 3-10 cycles.

12. The oil extraction apparatus as described in claim 7, wherein, Each cycle lasts 10-20 minutes.

13. The oil extraction apparatus as described in any one of claims 1 to 12, wherein, The area where the leaked grease accumulates is the housing area below the bearing inside the wind turbine generator housing, wherein the grease extraction device further includes a mounting for installing the inlet in the housing area below the bearing.

14. A method for extracting leaked grease from a leaked grease accumulation area at the base of a wind turbine generator housing, comprising: Position the inlet of the suction tube at the area where the leaked grease has accumulated; A vacuum pump is used to create negative pressure in the suction duct to draw in leaked grease through the inlet; And to collect any leaked grease inhaled through the inhalation cannula in a collection chamber connected to the inhalation cannula.

15. The method as described in claim 14, wherein, The step of generating negative pressure in the suction duct includes using a controller to control the vacuum pump to periodically initiate an extraction operation, during which the vacuum pump generates the negative pressure.

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