Filter system, gearbox system for a wind turbine, wind turbine and method for changing an oil filter of a gearbox system

Abstract

Filter system, gearbox system for a wind turbine, wind turbine and method for changing an oil filter of a gearbox system. The present invention is directed to a filter system for a wind turbine, comprising at least one filter device having a filter compartment with a volume portion and a cover portion, both defining a filter volume to receive the oil filter. The filter compartment is equipped with an inlet port, an outlet port and a pressure port. The filter system further comprises a pressurization device having an interface port and means of supplying pressurized gas through the interface port, preferably into the filter compartment of the filter device. The pressurization device is configured to be connected to the pressure port, preferably by means of a compensating duct.Furthermore, a method is disclosed in which the pressurization device is connected to the filter compartment, the lubricant is discharged by applying pressurized gas to the filter volume, the cap portion is removed, and an oil filter is subsequently replaced.

Description

1 / 31 “FILTER SYSTEM, GEARBOX SYSTEM FOR A WIND TURBINE, WIND TURBINE AND METHOD FOR REPLACING A "Oil filter for a gearbox system" Field of invention

[001] The present invention relates generally to wind turbines and, more particularly, to a filter system for a wind turbine gearbox, specifically to a filter system for changing a gearbox oil filter. In addition, a method for changing an oil filter is described. Background of the Invention

[002] Wind energy is considered one of the cleanest and most environmentally friendly energy sources currently available, and wind turbines have been gaining increasing attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture the kinetic energy of the wind using known leaf principles and transmit the kinetic energy via rotational energy to rotate a shaft that couples the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy into electrical energy that can be fed into an electrical grid.

[003] Specifically, wind turbines comprise several mechanical components with moving parts supported by stationary structures. This causes friction phenomena between said parts, where lubrication systems are installed to prevent or reduce wear related to friction.

[004] A specific type of wind turbine, for example, the Danish model, includes a gearbox to change a slow rotational motion with high torque into a relatively slow rotation. Petition 870260025421, dated 03 / 18 / 2026, page 10 / 83 2 / 31 fast with reduced torque. For example, the said gearbox can be implemented as a planetary gearbox, optionally having an additional gear stage, in which a plurality of gearbox components are subject to liquid lubrication, for example, oil lubrication.

[005] For this purpose, pressurized lubricant is supplied to a variety of lubrication locations, preferably via a lubrication cycle that includes an oil filter.

[006] However, oil filters need to be replaced frequently, causing wind turbine downtime and other related disadvantages. Description of the Invention

[007] The realizations and advantages of the invention will be presented in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[008] In one embodiment, the present invention is directed to a filter system for a wind turbine. Specifically, the filter system is configured to allow the replacement of an oil filter in a wind turbine filter device. Possibly, the filter device is arranged in a lubrication loop to supply lubricant to a wind turbine gearbox system. The term “oil filter” reflects filter means for filtering particles from a lubricant and is not restricted to filtering oil exclusively.

[009] The filter system comprises at least one filter device having a filter compartment with a volume portion and a cover portion, both defining a filter volume to receive the oil filter. The filter compartment is equipped with an inlet port, an outlet port and a pressure port. In particular, the inlet port may be connected to a duct upstream of a lubrication loop of the system. Petition 870260025421, dated 03 / 18 / 2026, page 11 / 83 3 / 31 gearbox, the outlet port can be connected to a duct downstream of the lubrication cycle, where the pressure port is configured to allow compensation of excess or required fluid to or from the filter volume.

[010] For example, the pressure port can be connected via a compensation duct to a specific volume within the lubrication cycle, preferably to a gearbox volume to allow for pressure and / or volume compensation between the filter volume and the specific volume.

[011] For example, in the case of thermal expansion or shrinkage, a pressure gradient may be present between the filter volume and the gearbox volume. This pressure difference can be equalized between the two volumes by means of the pressure port and the compensation duct.

[012] Preferably, any component of the connection between the filter volume and the lubrication loop volume can be configured so that a gaseous fluid, such as air, can pass between the volumes, in contrast to where liquid lubricant, particularly due to its viscosity, can only traverse the compensation duct in a limited or totally prevented way. In other words, the compensation duct and / or pressure port comprise restrictive means configured to effectively prevent the passage of a liquid fluid, in particular where a gaseous fluid can effectively flow through the compensation duct and / or pressure port. In particular, the term “is effectively prevented from passing” reflects the fact that if a volumetric flow of a liquid fluid according to DIN 51517, at an absolute pressure gradient of 0.1 MPa (1 bar), a volumetric flow rate is less than 10 ml / s.For example, the compensation duct, the pressure port and / or another component of the connection between the filter volume and the gearbox volume may have an effective diameter of less than 5 mm. Petition 870260025421, dated 03 / 18 / 2026, page 12 / 83 4 / 31 preferably less than 3 mm, more preferably less than 2 mm.

[013] The filter system further comprises a pressurization device having an interface port and means of supplying pressurized gas through the interface port, preferably into the filter compartment of the filter device. The pressurization device is configured to be connected to the pressure port, preferably through the compensation duct. Thus, to connect the pressurization device with the filter volume, the compensation duct can be disconnected from the gearbox volume and connected to the interface port.

[014] According to an optional embodiment, the power source may be a pressurized gas source, for example, a compressor or, alternatively, a gas cartridge containing a pressurized gas such as carbon dioxide or nitrous oxide.

[015] According to a further and / or alternative embodiment, the pressurization device is firmly connected to the filter device or is even an integral component of the filter device. In this case, the filter device comprises the pressurization device in the form of an integral component, wherein the pressure port of the filter device and the interface part of the pressurization device are joined, thus allowing a connection between the pressurization device and the filter volume. According to this alternative, but not necessarily, an additional pressure port may be provided to allow a compensating connection between the filter volume and a lubrication cycle volume.

[016] According to one embodiment, the filter system is configured to provide lubrication to a wind turbine gearbox, wherein the filter volume is at least 5 l, in particular at least 10 l, preferably at least 15 l, and / or, wherein the gearbox is a wind turbine gearbox with a rated power of at least Petition 870260025421, dated 03 / 18 / 2026, page 13 / 83 5 / 31 minus 0.5 MW, in particular at least 1.5 MW, preferably at least 2 MW.

[017] The system according to an embodiment as described provides a notable benefit with respect to investment in maintenance, downtime and sustainability. For example, by connecting the pressurization device to the filter volume, the filter volume can be emptied of lubricant by pressing the lubricant present inside the filter volume out of the filter volume in the lubrication cycle. When the oil filter is replaced with a new oil filter, the lubricant from the lubrication cycle can re-enter the filter volume.

[018] The present invention provides the benefit that, firstly, it avoids emptying the filter volume when changing the oil filter by pouring lubricant from the filter volume into an external receptacle (e.g., bucket, container). This leads to handling and ergonomic benefits and therefore to a reduction in maintenance time, for example, by avoiding accidents during handling of the external lubricant container. Secondly, the lubricant present in the filter volume does not need to be disposed of. In particular, it is not necessary to transport the external receptacle full of lubricant from a wind turbine nacelle down the tower for safe disposal. Thirdly, no new lubricant needs to be recharged in the filter system lubrication cycle after performing an oil filter change.

[019] In the case where the filter device comprises more than one pressure port, for example, a first pressure port being connectable to the gearbox volume to allow pressure compensation between the filter volume and another volume of the lubrication cycle, and a second pressure port to allow connection of the filter volume to the pressurization device, the latter, second pressure port must be Petition 870260025421, dated 03 / 18 / 2026, page 14 / 83 6 / 31 understood as a functional pressure port to supply pressure to the filter volume. In this case, the first pressure port should be closed. Therefore, an embodiment of a filter system having a plurality of pressurization and / or compensation holes should still be considered as an embodiment having a single pressurization hole, where an additional pressurization or compensation hole is used to be connected to a volume of the lubrication cycle.

[020] According to one embodiment, the filter system comprises at least one downstream restriction device configured to allow lubricant to flow from the filter volume towards or into the downstream duct and to prevent lubricant from re-entering the filter volume from the downstream duct back into the filter volume through the outlet port. According to a specific embodiment, the downstream restriction device is a check valve, for example, located between the outlet port and the downstream duct.

[021] According to another embodiment, an upstream restriction device is provided, which is arranged and configured in such a way that, if necessary, no lubricant can substantially enter the filter volume and / or the filter device through the inlet port. For example, the upstream restriction device can be opened or closed, wherein the upstream restriction device must be closed when lubricant is forced out of the filter volume and / or when an oil filter change is actually in progress. According to a specific embodiment, the upstream restriction device can be functionally implemented by a specific upstream valve and / or by a lubrication cycle pump.

[022] According to an example embodiment, the volume portion of the filter compartment is formed by a comprehensive part Petition 870260025421, dated 03 / 18 / 2026, page 15 / 83 7 / 31 longitudinal and a lower part, wherein, preferably, the encompassing part has a cylindrical shape and wherein the lower part is connected to a lower side of the encompassing part. The exit port is arranged in the lower part, for example, centrally in the lower part, and / or wherein the entrance port is arranged in the encompassing part. For example, the volume portion may be formed as a cylinder closed on one side by the lower part, wherein the entrance port passes through the cylindrical side walls of the encompassing part.

[023] The lid portion can be fixed to an upper part of the volume portion while isolating the filter volume from the environment. For this purpose, mounting and sealing means can be provided between the lid portion and the volume portion, for example, in the form of a thread and / or sealing lips.

[024] The above embodiments come with the benefit that the filter compartment that forms the filter volume is configured to receive an oil filter when the filter compartment is opened by separating the lid portion from the volume portion, while the flow of lubricant through this oil filter is enabled by the inlet port and the outlet port.

[025] According to further development, the pressure port is arranged in the cap portion. This helps to smooth the process of pushing the lubricant from the filter volume to the outlet port.

[026] Alternatively, the pressure port is placed in the comprehensive part of the volume portion, preferably on the upper side.

[027] According to a more specific, non-limiting embodiment, the filter system comprises an oil filter that is disposed within the filter compartment. The cover portion is mounted on the volume portion. The oil filter itself has a similar cylindrical shape, including an upper surface and a lower surface. The sealing means Petition 870260025421, dated 03 / 18 / 2026, page 16 / 83 The upper 8 / 31 sealing elements are effectively arranged between the upper surface and an inner surface of the lid portion, and the lower sealing elements are arranged between the lower surface and an inner surface of the lower part.

[028] Specifically, the filter compartment, the oil filter, the lower sealing means and the upper sealing means and their respective surfaces are designed and configured in such a way that the filter volume is separated by the oil filter into an inlet volume and an outlet volume. The inlet volume is connected to the inlet port, where the outlet volume is connected to the outlet port. Consequently, the lubricant, upon entering the inlet port, reaches the inlet volume. Subsequently, the lubricant can pass through the oil filter from the inlet volume to the outlet volume, where diversion of the oil filter is not possible due to the sealing means effectively arranged on the related surfaces.

[029] In the course of further development, it is disclosed that the pressure port is preferably exclusively connected to the inlet volume. This ensures that the lubricant being forced out of the filter volume is forced to flow through the oil filter, so that unfiltered lubricant cannot re-enter the lubrication cycle.

[030] According to a general embodiment, the pressurization device is configured in such a way that the relative pressure of the supplied gas in relation to ambient pressure and / or in relation to a pressure existing in the filter volume does not exceed 0.4 MPa (4 bar), in particular does not exceed 0.25 MPa (2.5 bar), preferably does not exceed 0.2 MPa (2 bar). Specifically, the pressurization device may comprise pressure-reducing means, for example, a pressure-reducing valve, to reduce the pressure of a gas supplied by the feed means to the aforementioned values. Petition 870260025421, dated 03 / 18 / 2026, page 17 / 83 9 / 31

[031] According to a further or alternative embodiment, a gearbox system for a wind turbine is provided, the gearbox system including at least one gearbox with a gearbox volume and a lubrication cycle to provide a circulating flow of lubricant to the gearbox lubrication locations. The lubrication cycle may comprise a filter system according to one or a combination of previously disclosed embodiments of a filter system, a pump to transport and / or pressurize lubricant in the lubrication cycle and connecting duct means including the upstream duct, the downstream duct and possible additional connecting ducts.

[032] In general, the lubrication cycle according to the embodiment described, but not limited to it, may also comprise parts of the gearbox volume, specifically a gearbox oil sump. The oil reservoir is connected, for example, to a cooling device and / or a reservoir by means of connecting ducts. Further on, the lubricant may enter a pump that transports and / or pressurizes it towards the inlet port of the filter device. From there, the lubricant passes through the oil filter via the inlet port, outlet port, through the check valve to the downstream duct. The downstream duct is connected to specific gearbox lubricant guide channels, wherein said channels allow the pressurized lubricant to be supplied directly to lubrication points such as bearings or gear teeth.By lubricating these lubrication points, the lubricant is collected in the gearbox oil reservoir and repeats its cycle.

[033] According to one embodiment of the gearbox system, the compensation duct connects a pressure port of the filter compartment with the gearbox volume, in which the duct Petition 870260025421, dated 03 / 18 / 2026, page 18 / 83 The 10 / 31 compensation duct is detachably mounted to the pressure port and / or in the gearbox housing. Thus, if the pressurization device is to be connected to the filter device, preferably the compensation duct is disconnected from the gearbox housing and subsequently connected to the interface port of the pressurization device.

[034] Alternatively, the compensation duct can be disconnected from the pressure port, where the interface port is connected directly or via an additional connection duct to the pressure port.

[035] According to an embodiment of the present invention, a method for changing an oil filter of a gearbox system is described. The gearbox system may be implemented according to one or a plurality of the embodiments described above, in particular, the gearbox system comprises a filter system according to one or a plurality of the aforementioned embodiments of the filter system. The method includes the following steps, it being understood that the method may further include any of the additional steps and / or features described in this document:

[036] The pressurization device is connected to the pressure port. If the pressurization device is integrally formed by the filter device, the connection step of the pressurization device is materialized by the fact that the interface port of the pressurization device is constantly connected to the pressure port of the filter device and / or the interface port and the pressure port are functionally merged with each other.

[037] If applicable, before performing the step of connecting the pressurization device to the pressure port, the compensation duct may be disconnected from the pressure port and / or the gearbox volume in order to allow the pressurization device to be connected to the port. Petition 870260025421, dated 03 / 18 / 2026, page 19 / 83 11 / 31 pressure.

[038] After the pressurization device connection step, pressurized gas is applied to the filter volume, in particular to the inlet volume. The lubricant inside the filter volume is then discharged through the outlet port. In particular, the pressure can be adjusted so that the pressure in the inlet volume does not exceed the pressure in the outlet volume of the filter volume by 0.4 MPa (4 bar), in particular does not exceed 0.25 MPa (2.5 bar), preferably does not exceed 0.2 MPa (2 bar). By limiting the pressure, it is ensured that a bypass valve in the oil filter is not opened by the pressure gradient.

[039] Preferably, during the preparation stage, the lubrication cycle pump is securely switched off before the pressurized gas application stage in the filter volume is carried out and, in particular, after the wind turbine power generation operation has finished.

[040] The above-mentioned step of supplying pressurized gas results in the replacement of the lubricant within the filter volume by the pressurized gas from the pressurization device, wherein the lubricant is discharged into the downstream pipeline through the outlet port. The check valve prevents the lubricant from re-entering the outlet volume. Furthermore, the lubricant in the filter volume cannot be discharged through the inlet pipeline, since the upstream restriction device, for example, the oil pump, effectively blocks the passage.

[041] In particular, but not limited to, the supply of pressurized gas may be terminated, in particular when a lubricant level within the filter volume falls below a predefined limit.

[042] After emptying the lubricant filter volume during the application of pressurized gas, the cap portion can be removed from Petition 870260025421, dated 03 / 18 / 2026, page 20 / 83 12 / 31 portion of filter compartment volume.

[043] By applying an optional additional step, the pressure inside the filter volume can be equalized with an ambient pressure outside the filter volume, in particular before removing the lid portion. By this means, maintenance personnel are protected from being harmed, for example, by a lid portion “exploding”.

[044] The filter compartment is now open and the filter volume is accessible. Therefore, the oil filter can be changed by removing the current oil filter and inserting a new oil filter or a clean oil filter.

[045] In a final step, before reactivating the pump and subsequently resuming operation of the wind turbine, the cap portion must be reassembled onto the volume portion.

[046] By applying a method according to one of the previous embodiments or according to a combination thereof to a filter system and / or a gearbox system, the process of changing an oil filter is drastically improved. Consequently, by not applying the present invention, the lubricant inside the filter device is subject to being spilled into an external receptacle which subsequently had to be carried from the nacelle to the wind turbine ground. This caused a large delay in changing the oil filter, a high risk of danger to the maintenance team and a loss of lubricant. All these disadvantages are eliminated by the invention described. The filter device is cleaned of lubricant by discharging it using external pressure. When the oil filter change is completed, the lubricant re-enters the filter device from the remaining lubrication cycle, in particular when the pump is reactivated.

[047] In another embodiment, the present invention is directed to a wind turbine having a nacelle mounted on top of a tower, wherein a gearbox system according to one or a plurality of Petition 870260025421, dated 03 / 18 / 2026, p. 21 / 83 13 / 31 previous embodiments are mounted on a support structure or main nacelle frame to transform a low-speed rotational motion with high torque from a wind turbine rotor into a relatively high-speed rotation with relatively reduced torque. Applying said gearbox system to a wind turbine allows for the benefit of reducing wind turbine downtime and increasing energy production.

[048] These and other features, achievements and advantages of the present invention will be further supported and described with reference to the following description and appended claims. The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Brief Description of the Drawings

[049] A complete and enabling invention of the present invention, including the improved embodiment thereof, directed to a person skilled in the art, is presented in the descriptive report, which refers to the accompanying Figures, in which: Figure 1 illustrates a perspective view of one embodiment of a wind turbine according to the present invention; Figure 2 illustrates a simplified internal view of one embodiment of a wind turbine nacelle according to the present invention having an embodiment of a filter system; Figure 3 is a schematic representation of the filter system according to Figure 2; Figure 4 illustrates the steps of a method for changing an oil filter in the filter system according to Figure 2; Figure 5 illustrates other steps in the method for replacing a filter. Petition 870260025421, dated 03 / 18 / 2026, page 22 / 83 14 / 31 oil from the filter system according to Figure 2; Figure 6 illustrates other steps in the method for changing an oil filter in the filter system according to Figure 2; Figure 7 illustrates other steps in the method for changing an oil filter in the filter system according to Figure 2; and Figure 8 illustrates other steps in the method for changing an oil filter in the filter system according to Figure 2.

[050] Individual features represented in the Figures are shown relative to each other and are therefore not necessarily to scale. Similar or identical elements in the Figures, even if displayed in different embodiments, are represented with the same reference numbers. Description of Embodiments of the Invention

[051] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not as a limitation of the invention. Indeed, it will be evident to those skilled in the art that various modifications and embodiments can be made to the present invention without departing from the scope of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to produce yet another embodiment. Thus, the present invention is intended to cover such modifications and embodiments that are within the scope of the appended claims and their equivalents.

[052] Figure 1 is a perspective view of an example wind turbine (10). In the example embodiment, the wind turbine (10) is a horizontal axis wind turbine. Alternatively, the wind turbine (10) may be a vertical axis wind turbine. In the example embodiment, the Petition 870260025421, dated 03 / 18 / 2026, p. 23 / 83 15 / 31 wind turbine (10) includes a tower (12) extending from a support system (14), a nacelle (16) mounted on the tower (12) and a rotor (18) that is coupled to the nacelle (16). The rotor (18) includes a rotating hub (20) and at least one rotor blade (22) coupled to and extending out from the hub (20). In the example embodiment, the rotor (18) has three rotor blades (22). In an alternative embodiment, the rotor (18) includes more or less than three rotor blades (22). In the example embodiment, the tower (12) is made of tubular steel to define a cavity (not shown in Figure 1) between a support system (14) and the nacelle (16). In an alternative embodiment, the tower (12) is any suitable type of tower having any height.

[053] The rotor blades (22) are spaced around the hub (20) to facilitate rotation of the rotor (18) to allow kinetic energy to be transferred from the wind to usable mechanical energy and subsequently electrical energy. The rotor blades (22) are coupled to the hub (20) by coupling a portion of the blade root (24) to the hub (20) in a plurality of load transfer regions (26). The load transfer regions (26) may have a hub load transfer region and a blade load transfer region (both not shown in Figure 1). Loads induced to the rotor blades (22) are transferred to the hub (20) through the load transfer regions (26).

[054] In one embodiment, the rotor blades (22) have a length ranging from about 15 meters (m) to about 91 m. Alternatively, the rotor blades (22) may have any suitable length that allows the wind turbine (10) to operate as described in this document. For example, other non-limiting examples of blade lengths include 20 m or less, 37 m, 48.7 m, 50.2 m, 52.2 m, or a length that is greater than 91 m. As the wind strikes the rotor blades (22) from a wind direction (28), the rotor (18) is rotated about an axis of rotation (30). As the Petition 870260025421, dated 03 / 18 / 2026, p. 24 / 83 16 / 31 rotor blades (22) are rotated and subjected to centrifugal forces, the rotor blades (22) are also subjected to various forces and moments. As such, the rotor blades (22) can deflect and / or rotate from a neutral or non-deflected position to a deflected position.

[055] Furthermore, a pitch angle of the rotor blades (22), that is, an angle that determines a perspective of the rotor blades (22) in relation to the wind direction, can be altered by a pitch system (32) to control the load and energy generated by the wind turbine (10) by adjusting an angular position of at least one rotor blade (22) in relation to the wind vectors. The pitch axes (34) of the rotor blades (22) are shown. During the operation of the wind turbine (10), the pitch system (32) can change a pitch angle of the rotor blades (22) so that the rotor blades (22) are moved to a feathered position, so that the perspective of at least one rotor blade (22) in relation to the wind vectors provides a minimum surface area of ​​the rotor blade (22) to be oriented towards the wind vectors, which facilitates a reduction in rotational speed and / or facilitates a stop of the rotor (18).

[056] In the example embodiment, a blade pitch of each rotor blade (22) is individually controlled by a wind turbine controller (36) or by a pitch control system (80). Alternatively, the blade pitch for all rotor blades (22) can be controlled simultaneously by said control systems.

[057] Furthermore, in the example embodiment, as the wind direction (28) changes, a yaw direction of the nacelle (16) can be rotated around a yaw axis (38) to position the rotor blades (22) relative to the wind direction (28).

[058] In the example embodiment, the wind turbine controller (36) is shown as being centralized within the nacelle (16), however, the wind turbine controller (36) can be a distributed system in Petition 870260025421, dated 03 / 18 / 2026, page 25 / 83 17 / 31 the entire wind turbine (10), in the support system (14), within a wind farm, and / or in a remote control center. The wind turbine controller (36) includes a processor (40) configured to execute the methods and / or steps described herein. In addition, many of the other components described in this document include a processor. As used herein, the term “processor” is not limited to integrated circuits referred to in the art as a computer, but refers broadly to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application-specific integrated circuit and other programmable circuits, and these terms are used interchangeably herein. It should be understood that a processor and / or a control system may also include memory, input channels and / or output channels.

[059] Figure 2 is an enlarged cutaway view of a portion of the wind turbine (10). In the example embodiment, the wind turbine (10) includes the nacelle (16) and the rotor (18) which is rotatably coupled to the nacelle (16). More specifically, the hub (20) of the rotor (18) is rotatably coupled to an electric generator (42) positioned within the nacelle (16) by the main shaft (44), a gearbox (166), a high-speed shaft (48) and a coupling (50). In the example embodiment, the main shaft (44) is at least partially coaxial to a longitudinal axis (not shown) of the nacelle (16). A rotation of the main shaft (44) drives the gearbox (166) which subsequently drives the high-speed shaft (48) by translating the relatively slow rotational motion of the rotor (18) and the main shaft (44) into a relatively fast rotational motion of the high-speed shaft (48).The latter is connected to the generator (42) to generate electrical energy with the help of a coupling (50).

[060] The gearbox (166) is part of a gearbox system (160) comprising at least the gearbox Petition 870260025421, dated 03 / 18 / 2026, page 26 / 83 18 / 31 gears (166) and a lubrication cycle (170) as shown in Figure 3. The lubrication cycle (170) supplies lubricant (168) to lubrication locations, such as bearings and gear teeth, of the gearbox (166). Subsequently, the lubricant (168) is collected in the gearbox (166), in particular in an oil reservoir (186) of the gearbox (166), then pressurized by a pump (182), filtered by a filter device (102) and repeatedly supplied to the lubrication locations. In addition, the thermal energy generated by and / or present in the gearbox (166) can be transported by the lubrication cycle (170) to a cooling device (188) being disposed downstream of the gearbox (166).

[061] The gearbox system (160) and the generator (42) may be supported by a main support frame of the nacelle (16), optionally incorporated as a main frame (52). The gearbox (166) may include a gearbox housing (162) which is connected to the main frame (52) by one or more torque arms (103). In the example embodiment, the nacelle (16) also includes a main front support bearing (60) and a main rear support bearing (62). Furthermore, the generator (42) may be mounted on the main frame (52) by means of a decoupling support (54), in particular in order to prevent vibrations from the generator (42) from being introduced into the main frame (52) and thus causing a source of noise emission.

[062] Preferably, the main frame (52) is configured to support all the load caused by the weight of the rotor (18) and nacelle components (16) and by wind and rotational loads and, in addition, to introduce these loads into the tower (12) of the wind turbine (10). The rotor shaft (44), generator (42), gearbox (166), high-speed shaft (48), coupling (50) and any associated fastening, support and / or fixing device, including, but not limited to, frame (52) and front support bearing (60) and bearing of Petition 870260025421, dated 03 / 18 / 2026, page 27 / 83 19 / 31 rear support (62), are sometimes referred to as a drive train (64).

[063] The nacelle (16) may also include a yaw drive mechanism (56) which may be used to rotate the nacelle (16) and thus also the rotor (18) around the yaw axis (38) to control the perspective of the rotor blades (22) with respect to the wind direction (28).

[064] To position the nacelle appropriately in relation to the wind direction (28), the nacelle (16) may also include at least one weather mast (58) which may include a wind vane and anemometer (none shown in Figure 2). The mast (58) provides information to the wind turbine controller (36) which may include wind direction and / or wind speed.

[065] In the example embodiment, the pitch system (32) is at least partially arranged as a pitch assembly (66) in the hub (20). The pitch assembly (66) includes one or more pitch drive systems (68) and at least one sensor (70). Each pitch drive system (68) is coupled to a respective rotor blade (22) (shown in Figure 1) to modulate the pitch angle of a rotor blade (22) along the pitch axis (34). Only one of the three pitch drive systems (68) is shown in Figure 2.

[066] In the example embodiment, the stepper assembly (66) includes at least one stepper bearing (72) coupled to the hub (20) and to a respective rotor blade (22) (shown in Figure 1) to rotate the respective rotor blade (22) around the stepper axis (34). The stepper drive system (68) includes a stepper drive motor (74), a stepper drive gearbox (76) and a stepper drive pinion (78). The stepper drive motor (74) is coupled to the stepper drive gearbox (76) such that the stepper drive motor (74) transmits mechanical force to the stepper drive gearbox (76). The stepper drive gearbox Petition 870260025421, dated 03 / 18 / 2026, page 28 / 83 20 / 31 (76) is coupled to the step drive pinion (78) so that the step drive pinion (78) is rotated by the step drive gearbox (76). The step bearing (72) is coupled to the step drive pinion (78) so that the rotation of the step drive pinion (78) causes a rotation of the step bearing (72).

[067] The stepper drive system (68) is coupled to the wind turbine controller (36) to adjust the pitch angle of a rotor blade (22) after receiving one or more signals from the wind turbine controller (36). In the example embodiment, the stepper drive motor (74) is any suitable motor driven by electrical power and / or a hydraulic system that enables the stepper assembly (66) to operate as described in this document. Alternatively, the stepper assembly (66) may include any suitable structure, configuration, arrangement and / or components, such as, but not limited to, hydraulic cylinders, springs and / or servomechanisms. In certain embodiments, the stepper drive motor (74) is driven by energy extracted from a rotational inertia of the hub (20) and / or a stored energy source (not shown) that supplies energy to the wind turbine components (10).

[068] The step assembly (66) also includes one or more step control systems (80) to control the step drive system (68) according to control signals from the wind turbine controller (36), in the case of specific prioritized situations and / or during excessive rotor speed (18). In the example embodiment, the step assembly (66) includes at least one step control system (80) communicatively coupled to a respective step drive system (68) to control the step drive system (68) independently of the wind turbine controller (36). In the example embodiment, the step control system (80) is coupled to the step drive system (68) Petition 870260025421, dated 03 / 18 / 2026, page 29 / 83 21 / 31 and a sensor (70). During normal operation of the wind turbine (10), the wind turbine controller (36) controls the pitch drive system (68) to adjust a pitch angle of the rotor blades (22).

[069] In one embodiment, in particular when the rotor (18) operates at excessive rotor speed, the pitch control system (80) replaces the wind turbine controller (36), so that the wind turbine controller (36) no longer controls the pitch control system (80) and the pitch drive system (68). Thus, the pitch control system (80) is able to cause the pitch drive system (68) to move the rotor blade (22) to a feathered position to reduce the rotational speed of the rotor (18).

[070] According to one embodiment, a power generator (84), for example, comprising a battery and / or electrical capacitors, is disposed in or within the hub (20) and is coupled to the sensor (70), the step control system (80) and the step drive system (68) to provide a power source for these components. In the example embodiment, the power generator (84) provides a continuous power source to the step assembly (66) during the operation of the wind turbine (10). In an alternative embodiment, the power generator (84) provides power to the step assembly (66) only during a power loss event of the wind turbine (10). The power loss event may include loss or failure of the power grid, malfunction of an electrical system of the wind turbine (10) and / or failure of the wind turbine controller (36).During the power loss event, the power generator (84) operates to supply electrical power to the stepper assembly (66) so that the stepper assembly (66) can operate during the power loss event.

[071] In the example embodiment, the system of Petition 870260025421, dated 03 / 18 / 2026, page 30 / 83 22 / 31 step drive (68), the sensor (70), the step control system (80), cables and the power generator (84) are each positioned in a cavity (86) defined by an inner surface (88) of the hub (20). In an alternative embodiment, said components are positioned relative to an outer surface (90) of the hub (20) and can be coupled, directly or indirectly, to the outer surface (90).

[072] Figure 3 is a schematic representation of one embodiment of a filter system (100) for the gearbox system (160) of the wind turbine (10). Specifically, the lubrication cycle (170) is schematically represented, wherein the lubrication cycle (170) allows a cyclic flow of lubricant (168) from a reservoir (180) to a pump (182), which pressurizes and transports the lubricant (168) through an upstream duct (172) towards an inlet port (124) of a filter device (102) of a filter system (100). After being filtered by an oil filter (150) of the filter device (102), the lubricant (168) enters a downstream duct (174) passing through an outlet port (134) and a check valve (184). The downstream duct (174) connects the filter system (100) with the gearbox (166) having a gearbox volume (164) inside the gearbox compartment (162).In particular, the downstream duct (174) is connected to unshown guide channels in the gearbox compartment (162), which connect the downstream duct (174) to the lubrication points. After lubricating the lubrication points, the lubricant (168) is collected in the gearbox (166), for example, in the lower part of the gearbox volume (164), in particular in the oil reservoir (168). Further on, the lubricant flows through the cooling device (188) before re-entering the reservoir (180).

[073] The filter device (102) is configured to receive the Petition 870260025421, dated 03 / 18 / 2026, page 31 / 83 23 / 31 oil filter (150) in a filter volume (112) of the filter compartment (110), wherein the filter compartment (110) may be structured in a volume portion (120) and a cover portion (140). The cover portion (140) may be mounted over the volume portion (120) so that the filter volume (112) is hermetically sealed from the environment. However, the filter volume (112) is connected to the upstream duct (172) by means of the inlet port (124), to the downstream duct (174) by means of the outlet port (134) and, optionally, to the gearbox volume (164) by means of a pressure port (144).

[074] The volume portion (120) consists of at least one encompassing part (122), preferably having a cylindrical shape, and a lower part (132), wherein the lower part (132) is connected to a lower side (126) of the encompassing part (120).

[075] According to this specific example, however, but not limited to, the outlet port (134) is disposed in the lower part (132). Furthermore, the check valve (184) may be disposed directly in the outlet port (134) and / or in the lower part (132), and / or the check valve (184) may be integrated into the lower part (132).

[076] The lid portion (140) may comprise the pressure port (144) and may be mounted on an upper side (128) of the volume portion (120) in a sealing manner, for example, by screwing the lid portion (140) onto a thread (142) of the volume portion (120).

[077] The downstream duct (174) connects the gearbox (166) with the outlet port (134) and / or with the check valve (184), wherein the upstream duct (172) provides a direct connection from the pump (182) to the filter volume (112). According to this specific embodiment, the gearbox (166) comprises the oil sump (186), the cooling device (188) is disposed downstream of the gearbox (166) and the Petition 870260025421, dated 03 / 18 / 2026, page 32 / 83 24 / 31 upstream of the reservoir (180) and the pump (182) is placed downstream of the reservoir (180) and upstream of the filter device (102) and the gearbox (166).

[078] However, and according to one embodiment, the present invention explicitly includes lubrication cycles having a different configuration, for example, a lubrication cycle having a cooling device located downstream of the pump (182), or, wherein the gearbox would not comprise an oil reservoir (186), and / or, wherein the reservoir is not provided or is located in a different position within the lubrication cycle.

[079] During normal operation of the wind turbine (10), therefore, the wind turbine (10) is generating energy or at least its rotor (18) is rotating, the cover portion (140) is firmly mounted on the volume portion (120) and the oil filter (150) is disposed in the filter volume (112) of the filter compartment (110). With this, the oil filter (150) divides the filter volume (112) into an inlet volume (114) being connected to the inlet port (124) and an outlet volume (116) being connected to the outlet port (134). For this purpose, lower sealing means (152) and upper sealing means (154) are provided in order to create a sealed connection between a lower surface of the oil filter (150) and an inner lower surface of the lower part (132) and to create a sealed connection between an upper surface of the oil filter (150) and an inner cover surface of the cover portion (140).These sealing connections between the oil filter (150) and the bottom (132) and the cover portion (140) prevent the lubricant from diverting from the oil filter (150) directly from the inlet volume (114) to the outlet volume (116).

[080] In addition, during normal operation, the pressure port (144) is connected to the gearbox volume (164) using a compensation duct (178). Petition 870260025421, dated 03 / 18 / 2026, page 33 / 83 25 / 31

[081] According to one embodiment, the pressure port (144) is arranged in such a way in the cover portion (140) that the pressure port (144) is connected to the inlet volume (114). Therefore, air possibly being transported from the pump (182) to the inlet volume (114) can escape from the filter device (102) and divert the oil filter (150) directly to the gearbox volume (164). Preferably, the connection between the filter volume (112) and the gearbox volume (164), for example, the compensation duct (178), the pressure port (144) and / or a pressure port disposed in the gearbox volume (164) is implemented in such a way that the lubricant (168) is effectively prevented from passing through said connection, in particular from the filter volume (112) to the gearbox volume (164), where a gaseous fluid, for example, air, can pass.This ensures that the lubrication points are constantly supplied with lubricant (168) and that a gaseous fluid, such as air, does not reach said lubrication points, possibly resulting in ineffective lubrication and potential damage.

[082] In addition, the filter system (100) comprises a pressurization device (200) that can be connected to the filter volume (112) through the pressure port (144) and through an interface port (202) of the pressure boosting device (200). The pressurization device (200) comprises at least gas supply means, in this example, a gas cartridge (204) and may further comprise a pressure adjusting valve (206) and / or a pressure gauge (208).

[083] According to the embodiment of Figure 3 to Figure 8, the pressurization device (200) can be implemented as a separate device that can be connected to the filter device (102) if the oil filter (150) needs to be replaced.

[084] According to an additional embodiment and / or Petition 870260025421, dated 03 / 18 / 2026, page 34 / 83 26 / 31 alternative (not shown), a pressurization device can be firmly connected to the filter device or perhaps even be an integral component of the filter device.

[085] Figures 4 to 8 represent various steps of a method for changing the oil filter (150) of the filter system (100), wherein the invention is not limited to all of the steps presented, but also a selection of steps may sufficiently serve the purpose of the present invention.

[086] Figure 4 shows the filter system (100), in which, according to an optional step (300), the compensation duct (178) is disconnected from the gearbox (166).

[087] Before this, an optional step of shutting down the wind turbine operation and / or an optional step of safely deactivating the pump (182) may be conducted. In particular, the safe deactivation of the pump (182) results in the pump (182) not being able to be activated by means of another controller or control unit, such as the wind turbine controller (36).

[088] According to another step (302), the pressurization device (200) is connected to the pressure port (144), in particular using the compensation duct (178), for example, its end which was previously connected to the gearbox (166).

[089] According to the embodiment of a pressurization device integrated into the filter device, the step (302) of connecting a pressurization device with a pressure port is carried out permanently, specifically by the integrated design, even if there are valve means being provided between the pressurization device's supply means and the filter volume.

[090] After establishing a connection between the pressurization device (200) and the filter device (102), a step (304) of Petition 870260025421, dated 03 / 18 / 2026, page 35 / 83 27 / 31 application of pressurized gas into the filter volume (112), in particular into the inlet volume (114) to discharge (308) the lubricant (168), as shown in Figure 5. This can be performed by opening the pressure adjustment valve (206) of the pressurization device (200). In fact, the lubricant (168) being present in the inlet volume (114) and in the outlet volume (116) is forced to leave the filter volume (112) through the outlet port (134) and the check valve (184).

[091] While a pressure within the filter volume (112) caused by the pressurization device (200) is greater than a pressure in the downstream duct (174), the lubricant level is reduced (306). When a level of lubricant (168) in the filter volume (112) is below a predefined limit, the application of pressurized gas is terminated (310), for example, by closing the pressure adjustment valve (206). Preferably, the termination (310) is conducted when essentially all the lubricant (168) – for example, more than 90 percent of the filter volume (112) – has been discharged (308) as shown in Figure 6.

[092] As represented in Figure 7, the portion of the cover (140) is removed by a step (312), preferably, before which a pressure equalization step is conducted between the filter volume (112) and the ambient pressure, for example, by releasing excess pressure from the filter volume (112). This measure increases the safety of maintenance personnel.

[093] Now, the oil filter (150) must be replaced (314) by removing it (315) from the filter volume (112) and replacing it (316) with a new oil filter (158) or clean oil filter (150) (see Figures 7 and 8).

[094] Having the replaced oil filter (158) disposed in the filter volume (112), the cap portion (140) can be reassembled in the volume portion (120). Optionally, as soon as possible after having finished (310) the application of Petition 870260025421, dated 03 / 18 / 2026, page 36 / 83 28 / 31 gas, the pressurization device (200) - if suitable - can be disconnected (318) from the filter device (102). In particular, if the pressurization device (200) was connected to the pressurization port (144) using the compensation duct (178), said compensation duct (178) can be reconnected to the gearbox (166).

[095] Finally, the safe deactivation of the oil pump (182) can be deactivated and the operation of the wind turbine (10) can be resumed.

[096] This written description uses examples to disclose the invention, including the best manner, and also to enable any person skilled in the art to practice the invention, including the manufacture and use of any devices or systems and the execution of any methods incorporated. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art, for example, the embodiment is closing a pressurization device integrated into the filter device (102). Such other examples are intended to be within the scope of the claims if they include elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[097] The present invention is not limited to the embodiments and modifications described above and may be incorporated in various forms within its essence, for example, the technical features of the embodiments and modifications corresponding to the technical features according to the embodiments described in the summary description section of the invention may be substituted or combined as appropriate to solve some or all of the problems described above or to obtain some or all of the effects described above, for example, the pressure equalization step may be integrated into the gas application closure step (310) in the volume of Petition 870260025421, dated 03 / 18 / 2026, page 37 / 83 29 / 31 filter (112). According to another example, the present invention is not limited to a wind turbine comprising such a gearbox system, but also to apparatus and machines having a gearbox system, for example, a gearbox of an ocean-going vessel.

[098] Technical characteristics may also be omitted as appropriate, unless they are described as essential in this descriptive report. Table 1 - Reference numbers 10 wind turbine 12 tower 14 support system 16 nacelle 18 rotor 20 rotating hub 22 rotor blades 24 blade root portion 26 load transfer regions 28 wind direction 30 rotation axis 32 pitch system 34 pitch shafts 36 wind turbine controller 38 yaw axis 40 processor 42 electric generator 44 main shaft 46 torque arm 48 high-speed shaft 50 coupling 52 main frame 54 decoupling support means 56 yaw drive mechanism 58 weather mast 60 front support bearing 62 rear support bearing 64 drive train 66 pitch assembly 68 pitch drive system 70 sensor 72 pitch bearing Petition 870260025421, dated 03 / 18 / 2026, page 38 / 83 30 / 31 74 Stepper drive motor 76 Stepper drive gearbox 78 Stepper pinion 80 Stepper control system 84 Power generator 86 Cavity 88 Internal surface 100 Filter system 102 Filter device 104 Axial direction 106 Radial direction 110 Filter compartment 112 Filter volume 114 Inlet volume 116 Outlet volume 120 Volume portion 122 Comprehensive part 124 Inlet port 126 Bottom side 128 Top side 132 Bottom part 134 Outlet port 140 Cover portion 142 Thread 144 Pressure port 150 Oil filter 152 Bottom sealing media 154 Top sealing media 156 Filter media 158 New oil filter 160 Gearbox system 162 Gearbox compartment 164 Gearbox volume 166 Gearbox 168 lubricant 170 lubrication cycle 172 upstream pipe 174 downstream pipe 178 compensation pipe 180 reservoir 182 pump 184 check valve 186 oil sump 188cooling device 200 pressurization device Petition 870260025421, dated 03 / 18 / 2026, page 39 / 83 31 / 31 202 Interface port 204 Gas cylinder 206 Pressure adjustment valve 208 Pressure gauge 300 Disconnecting the compensation duct 302 Connecting the pressurization device 304 Pressurized gas application 306 Lubricant level is reduced 308 Lubricant discharge 310 Ending pressure application 312 Removing the cap portion 314 Replacing the oil filter 315 Removing the oil filter 316 Inserting the oil filter 318 Disconnecting the pressurization device 320 Reassembling the cap portion 322 Reconnecting the compensation duct Petition 870260025421, dated 03 / 18 / 2026, page 40 / 83

Claims

1 / 5 Claims 1. FILTER SYSTEM (100) for changing an oil filter (150) from a filter device (102) of a gearbox system (160), the filter system (100) characterized by comprising: - the filter device (102) having a filter compartment (110) including a volume portion (120) and a cover portion (140), both defining a filter volume (112) for receiving the oil filter (150), an inlet port (124) being connectable to an upstream duct (172) of a lubrication loop (170) of the gearbox system (160), an outlet port (134) being connectable to a downstream duct (174) of the lubrication loop (170), and a pressure port (144) for applying pressure to the filter volume (112), - a pressurization device (200) including an interface port (202) being connectable to the pressure port (144) and means of supply (204) to supply pressurized gas to the filter compartment (110).

2. FILTER SYSTEM (100), according to claim 1, characterized in that the pressure port (144) is connectable to a volume of the gearbox (164) of the gearbox (166), in particular by a compensation duct (178), or in that the pressurization device (200) is integrally formed by a component of the filter device (102), such that the pressure port (144) and the interface port (202) are functionally fused together.

3. FILTER SYSTEM (100), according to any one of claims 1 to 2, characterized by comprising a check valve (184) being connected to the outlet port (134) downstream of the filter volume (112) to prevent lubricant (168) from flowing from the downstream duct (174) to the filter volume (112).

4. FILTER SYSTEM (100), according to any of claims 1 to 3, characterized in that the gearbox (166) is a gearbox (166) of a wind turbine (10), and in that the filter volume (112) is at least 5 liters, in particular at least 10 liters, preferably at least 15 liters.

5. FILTER SYSTEM (100), according to any one of claims 1 to 4, characterized in that: - the volume portion (120) being formed by a longitudinal encompassing part, preferably cylindrical (122) and by a lower part (132) being connected to a lower side (126) of the encompassing part (122), - the outlet port (134) being disposed, preferably centrally, in the lower part (132), and the inlet port (124) being disposed in the encompassing part (122), - the cover portion (140) being mounted in a sealed manner on an upper side (128) of the encompassing part (122) located opposite the lower side (126), and / or - the pressure port (144) being disposed in the cover portion (140).

6. FILTER SYSTEM (100), according to any one of claims 1 to 5, characterized in that the cover portion (140) is mounted on the volume portion (120), and the filter system (100) comprises: - an oil filter, preferably cylindrical (150) being disposed within the filter compartment (110); - upper sealing means (154) being effectively disposed between an upper surface of the oil filter (150) and an inner cover surface of the cover portion (140); and - lower sealing means (152) being effectively disposed between a lower surface of the oil filter (150) and an inner lower surface of the lower part (132); - wherein the filter compartment (110), the oil filter (150), the Petition 870260025421, dated 03 / 18 / 2026, page.42 / 83 3 / 5 lower sealing means (154) and upper sealing means (154) are configured in such a way that the filter volume (112) is divided by the oil filter (150) into an inlet volume (114) and an outlet volume (116), and in which the lubricant (158) flows from the inlet port (124) through the inlet volume (114) and through the outlet volume (116) to the outlet port (134) is forced to flow radially through the oil filter (150), in particular in such a way that the lubricant (158) is prevented from bypassing the oil filter (150) along one of its surfaces.

7. FILTER SYSTEM (100), according to claim 6, characterized in that the pressure port (144) is, in particular exclusively, connected to the inlet volume (114), and / or in that the check valve (184) is connected to the outlet volume (116).

8. FILTER SYSTEM (100), according to any one of claims 1 to 7, characterized in that the pressurization device (200) comprises pressure reduction means configured in such a way and / or in that the feed means (204) are configured in such a way that a relative pressure of the supplied gas applicable in the filter volume (112), in particular in the inlet volume (114), does not exceed 0.4 MPa, in particular does not exceed 0.25 MPa, preferably does not exceed 0.2 MPa.

9. GEARBOX SYSTEM (160) FOR A WIND TURBINE (10), the gearbox system (160) characterized by comprising at least one gearbox (166) having a gearbox volume (164) and a lubrication cycle (170) for providing a circulating flow of lubricant (168) to lubrication locations of the gearbox (166), the lubrication cycle (170) comprising at least: - a filter system (100) as defined in any one of claims 1 to 8; Petition 870260025421, dated 03 / 18 / 2026, p.43 / 83 4 / 5 - a pump (182) for pressurizing the lubricant (166) at least partially within the lubrication cycle (170), - connecting duct means including the upstream duct (172) connected to the inlet port (130) and the downstream duct (174) connected to the outlet port (134), wherein the connecting duct means (176) are configured to allow circulating flow of lubricant (168) between the filter system (100), the gearbox volume (164) and the pump (182).

10. GEARBOX SYSTEM (160), according to claim 9, characterized by comprising a compensation duct (178) connecting the pressure port (144) to the gearbox volume (164), wherein the compensation duct (178) is detachably mounted to the pressure port (144) and / or to the gearbox volume (164).

11. WIND TURBINE (10), characterized by comprising a turbine rotor (18) including a hub (20) and at least one rotor blade (22) mounted on a rotating turbine shaft (44), wherein the rotor blade (22) is rotatably arranged around its longitudinal axis in the hub (20), an induction generator (42) having a stator, a rotor and a gearbox system (160), as defined in any one of claims 9 to 10, for coupling the generator (42) to the turbine shaft (44) for rotation therewith.

12. METHOD FOR CHANGING AN OIL FILTER (150) OF A GEARBOX SYSTEM (160), as defined in any one of claims 9 to 10, the method characterized by comprising the steps: connecting (302) the pressurization device (200) to the pressure port (144); applying (304) pressurized gas to the filter volume (112), in particular to the inlet volume (114), to discharge the lubricant (308) from the filter volume (112); removing (312) the cap portion (140); replace (314) the oil filter (150), in particular by removing (315) the oil filter (150) and inserting (316) a new oil filter (158) or the clean oil filter (150); and reassemble (320) the cover portion (140) to the volume portion (120).

13. METHOD, according to claim 12, characterized by comprising the step: - safely deactivating the pump (182), at least before the step of removing (312) the cap portion (140), in particular before the step of applying pressurized gas (304).

14. METHOD, according to any one of claims 12 to 13, characterized by comprising at least one of the steps: (310) when a level of lubricant (168) within the filter volume (112) is below a predefined limit, shutting off (310) the application of pressurized gas (304); and / or - conducting pressure equalization between the filter volume (112) and an environment, in particular before removing (312) the cap portion (140).

15. METHOD, according to any one of claims 12 to 14, characterized by comprising at least one of the following steps: - shutting down the power generation of the wind turbine (10) and, in particular, operating the wind turbine (10) in idle operation; - disconnecting (300) the compensation duct (178) from the pressure port (144) and / or the gearbox volume (164); - shutting down the pump (182), in particular after having reassembled (320) the cover portion (140) to the volume portion (120); and / or - reconnecting (322) the compensation duct (178) with the pressure port (144) and / or with the gearbox volume (164). Petition 870260025421, dated 18 / 03 / 2026, p. 45 / 83

Images