Hydraulic device for a tilt system, tilt system and wind turbine

Abstract

The present invention relates to a hydraulic device 10 for a tilt system of a wind turbine, comprising an air separation device 18, wherein the air separation device 18 comprises a liquid separator 26 with an air collection section 28, at least one liquid inlet 30, and a liquid outlet section 32, wherein a liquid emulsion of air and hydraulic fluid can be introduced into the liquid separator 26 through the at least one liquid inlet 30. The liquid separator 26 is labyrinth-shaped, such that rotation of the air separation device 18 about a rotation axis causes the air in the liquid emulsion to move through the labyrinth-shaped liquid separator 26 toward the air collection section 28 and the hydraulic fluid in the liquid emulsion to move through the labyrinth-shaped liquid separator 26 toward the liquid outlet section 32.The invention further relates to a tilt system and a wind turbine.

Description

[0001] The present invention relates to a hydraulic device for a tilting system, a tilting system with such a hydraulic device and a wind turbine with such a tilting system.

[0002] Such tilt systems are known from the prior art and are also referred to as tilt control systems. These tilt systems are designed to adjust the aerodynamic tilt angle of one or more of the wind turbine's rotor blades, thereby setting the so-called tilt. For this purpose, the rotor blades are rotatably mounted on a hub of a wind turbine rotor via a tilt bearing and a tilt gear. The tilt system changes the tilt of the rotor blades depending on the current wind speed in order to operate the wind turbine with the best possible efficiency and thus with a largely constant rated power. The tilt angle of the rotor blades is adjusted for various purposes to achieve the desired lift of the blades, e.g., to bring the rotor to a standstill, to limit the energy supply from the wind to the blade, to perform maintenance work, and so on.In other words, the angle position is adjusted to the wind direction.

[0003] In addition, the tilt systems are designed to prevent damage to the wind turbine in strong winds by rotating the rotor blades out of the wind, i.e., into the so-called feather position. This interrupts the lift of the rotor blades and brings the rotor to a standstill, possibly with the assistance of a brake.

[0004] Known tilt systems comprise a hydraulic drive unit designed to adjust the tilt of one or all of the wind turbine's rotor blades. Therefore, a hydraulic actuator, e.g., a tilt cylinder, can be pressurized by a hydraulic pump to extend and retract to adjust the tilt. Typically, a hydraulic accumulator is provided to compensate for the volume difference between the piston and rod sides of the tilt cylinder. When the rod side of the piston is pressurized, the differential volume exiting the piston side is charged into the hydraulic accumulator. Accordingly, the hydraulic accumulator is relieved when the rod side of the tilt cylinder is pressurized.

[0005] Modern wind turbines are generally not directly driven, but have a gearbox between the hub and the generator located in the nacelle. Therefore, when hydraulic components such as the hydraulic pump and hydraulic accumulator are located in the nacelle, the lines must be routed through the gearbox, making maintenance and servicing of the lines very complicated. Since the hub rotates relative to the nacelle, rotary unions must also be installed to route the hydraulic fluid to the tilt cylinders. For safety reasons, the correct functioning of the wind turbine, and thus also of the rotary unions, must be tested before the wind turbine is first commissioned. Especially for offshore wind turbines, this means that the wind turbine must be pre-assembled for testing, or that the tests are carried out when the wind turbine is already at sea and fully assembled.In any case, this is cumbersome and causes high costs.

[0006] To reduce testing effort and minimize the number of transmission components and potential leak points, the hydraulic tilt system can be designed as a closed system located entirely within the hub. This eliminates the need for hydraulic rotary unions, and testing of the entire hydraulic tilt system can be performed before the wind turbine is installed. However, since the hydraulic pump rotates with the hub during operation of the wind turbine, it must be ensured that the tilt cylinder can be pressurized regardless of the orientation of the hydraulic pump.

[0007] It was therefore proposed to use a so-called bootstrap reservoir to ensure the supply of hydraulic fluid to the hydraulic pump in any orientation of the hub and thus of the hydraulic pump. Such bootstrap reservoirs typically comprise a reservoir piston that defines a variable-capacity fluid storage space and a pilot piston that acts on the reservoir piston. The pilot piston is pressurized by the pressure of the tilt system and, via the reservoir piston, creates a preload in the variable-capacity fluid storage space. A corresponding hydraulic tilt system is known, for example, from WO 2015 / 014367 A1.

[0008] However, during operation of the hydraulic tilt system, air or gas inevitably enters the hydraulic fluid, e.g., through the rod seals of the tilt cylinder, the piston seals of the bootstrap reservoir, the shaft seals of the hydraulic pump, or during maintenance or component replacement. Although bootstrap reservoirs are also known from other applications, such as aircraft hydraulics, venting is generally not a problem in these applications, as venting can be performed manually or through appropriate valves during normal maintenance while the aircraft is not in use.

[0009] However, manual venting of the hydraulic tilt system of an offshore wind turbine is usually not easily possible because the wind turbine is located far away and the time intervals between normal maintenance work are too long.

[0010] There is therefore a need to provide a hydraulic device for a tilt system that is installed entirely within the hub of a wind turbine and allows for facilitated venting.

[0011] The solution to the problem is achieved with a hydraulic device according to claim 1. Furthermore, the solution is also achieved with a tilt system according to claim 11 and a wind turbine according to claim 12. Preferred embodiments are described in the dependent claims.

[0012] According to the invention, a hydraulic device for a tilt system of a wind turbine is provided, comprising an air separation device. The air separation device comprises a fluid separator having an air collection section, at least one fluid inlet, and a fluid outlet section. A fluid emulsion of air and hydraulic fluid can be introduced into the fluid separator through the at least one fluid inlet. The fluid separator is labyrinth-shaped, such that rotation of the air separation device about a rotation axis causes the air in the fluid emulsion to move through the labyrinth-shaped fluid separator in a direction toward the air collection section. The rotation of the air separation device further causes the hydraulic fluid in the fluid emulsion to move through the labyrinth-shaped fluid separator in a direction toward the fluid outlet section.

[0013] During one rotation of the labyrinthine fluid separator, the shape of the labyrinth is such that a low-mass particle (i.e., air) starting from any position in the labyrinthine fluid separator will have changed its position in the labyrinthine fluid separator in a direction opposite to that of a high-mass particle (i.e., hydraulic fluid) starting from the same position. For each initial position of the particle, the direction of movement of the low-mass particle must be the same, namely, toward the air collection section. The axis of rotation need not pass through the air separation device. Rather, the axis of rotation may be the axis of rotation of the hub relative to the nacelle of the wind turbine.

[0014] Preferably, the hydraulic device comprises a reservoir with a variable-capacity liquid storage device. The labyrinth-shaped liquid separator may be wound around an axis. The axis may be a central axis. The air collection section may be the radially outermost section of the labyrinth-shaped liquid separator. The liquid outlet section may be arranged radially inward of the air collection section, and the at least one liquid inlet may be arranged between the liquid outlet section and the air collection section. The liquid outlet section is connected to the variable-capacity liquid storage device.

[0015] The labyrinth-shaped fluid separator is designed as a spiral fluid separator. The hydraulic fluid that is to enter the variable-capacity fluid reservoir must first pass through the spiral fluid separator. Since the air likely contained in the hydraulic fluid is lighter than the hydraulic fluid itself, it accumulates in the upper part due to gravity. Therefore, during the rotation of the hydraulic device, the air accumulates in the radially outermost air collection section, as this section rotates along with the hub during operation of the wind turbine. This allows the air to be separated from the hydraulic fluid.

[0016] Depending on the orientation of the labyrinth-shaped liquid separator (i.e., clockwise or counterclockwise) and the direction of rotation, the positions of the air collection section and the liquid outlet section can be changed. Therefore, the air collection section can also be the radially innermost section.

[0017] Preferably, the labyrinth-shaped liquid separator comprises a channel that is wound, preferably in a plane, around the central axis. The channel is thus wound in a plane around the central axis, which limits the required space due to its disc-shaped configuration.

[0018] Preferably, the fluid outlet section comprises at least one through-hole, which is preferably connected to the variable-capacity fluid reservoir. Preferably, a plurality of through-holes are provided so that the hydraulic fluid separated from the air can exit the air separation device.

[0019] Preferably, the hydraulic device further comprises an air outlet and an air release valve, wherein the air collection section is connected to the air outlet via the air release valve. By opening the air release valve, the air accumulated in the air collection section can exit the hydraulic device. When the air release valve is opened, the pressure of the hydraulic fluid forces the air through the air release valve.

[0020] Preferably, a first detection sensor arrangement is arranged in the air collection section, wherein the opening and closing of the air release valve is controlled via measurement signals from the first detection sensor arrangement. When sufficient air has accumulated in the air collection section, thereby displacing the hydraulic fluid, this is detected by the first detection sensor arrangement, and the air release valve is opened to release the air through the air outlet. The air release valve can remain open for a predetermined period of time or be closed again based on a measurement signal indicating the presence of hydraulic fluid in substantially the entire air collection section.

[0021] Preferably, the first detection sensor arrangement comprises an air detection sensor arranged at an end of the air collection section opposite the air outlet, and a liquid detection sensor arranged between the air detection sensor and the air outlet. Preferably, the liquid detection sensor is arranged in the immediate vicinity of the air outlet. Once sufficient air has accumulated in the air collection section, the air detection sensor detects the presence of air, and the air release valve is then opened. The pressure of the hydraulic fluid forces the air out of the air outlet, and the hydraulic fluid begins to fill the air collection section. When the air collection section is almost full of hydraulic fluid, this is detected by the liquid detection sensor, and the air release valve is then closed again.

[0022] It is also conceivable to provide an air collection section large enough to accommodate all the air accumulated between two maintenance sessions. In this case, the air release valve could be operated manually or the accumulated air could be released by connecting a minimal hose to a test point.

[0023] Preferably, the reservoir comprises a housing and a piston movably arranged within this housing, wherein the piston divides the housing into the variable-capacity liquid reservoir and an air space. The reservoir is preferably a bootstrap reservoir. Therefore, the piston can also be referred to as a reservoir piston.

[0024] Preferably, the air separation device is located in the housing. This allows for a compact design.

[0025] Preferably, the air collection section is connected to the air space. Since some hydraulic fluid may escape through the air outlet, the hydraulic fluid is not poured into the hub of the wind turbine but is directed into the air space for safety reasons. Hydraulic fluid may escape through the air outlet, e.g., due to a malfunction of the first detection sensor assembly or the air release valve.

[0026] Preferably, a second detection sensor arrangement is arranged in the air space. The second detection sensor arrangement is preferably designed to detect the presence of fluid in the air space. Therefore, if, for example, hydraulic fluid enters the air space due to a malfunction, this is detected by the second detection sensor arrangement, and appropriate measures can be taken.

[0027] Alternatively, the reservoir can also be designed as a low-pressure accumulator, with the hydraulic fluid being pressurized, for example, with nitrogen. Alternatively, the air separation device can be designed as a reservoir, with the hydraulic pump being directly connected to the fluid outlet section.

[0028] The invention further relates to a tilt system for a wind turbine, comprising at least one hydraulic actuator, a hydraulic pump, a hydraulic accumulator, and a hydraulic device as described above. The hydraulic device is connected to the hydraulic accumulator and the hydraulic pump, wherein the hydraulic pump is configured to drive the hydraulic actuator and charge the hydraulic accumulator.

[0029] The invention further relates to a wind turbine comprising a nacelle, a hub rotatably mounted on the nacelle, at least one rotor blade mounted on the hub, and at least one tilt system according to the invention. The at least one tilt system is arranged in the hub and is designed to adjust an angle of inclination between the at least one rotor blade and the hub. The wind turbine preferably comprises one tilt system according to the invention per rotor blade.

[0030] The invention is described below with reference to the figures. The figures schematically show Fig. 1 a side view of a wind turbine; Fig. 2 a hydraulic circuit diagram of a tilt system with a hydraulic device; Fig. 3 a perspective view of the hydraulic device; Fig. 4 a first side view of the hydraulic device of Fig. 3; Fig. 5 a first cross section along the Fig. 4 shown line AA; Fig. 6 a second side view of the hydraulic device of Fig. 3; Fig. 7 a second cross section along the Fig. 6 shown line AA; Fig. 8 a third cross-section along the Fig. 6 shown line BB; and Fig. 9 an overview of the states of the hydraulic device during the rotation of the wind turbine.

[0031] Fig. 1 shows a side view of a wind turbine 100 according to the invention. The wind turbine 100 comprises a tower 102 and a nacelle 104 attached to the tower 102. A hub 106 is rotatably mounted on the nacelle 104. The wind turbine 100 further comprises a plurality of rotor blades 108 attached to the hub 106. Within the hub 106, a hydraulic tilt system 110 (see Fig. 2). Each hydraulic tilt system 110 is designed to adjust the aerodynamic tilt angle of the associated rotor blade 108 of the wind turbine 100. The tilt system 110 changes the tilt angle of the rotor blade 108 depending on the current wind speed in order to operate the wind turbine 100 with the best possible efficiency and thus with a largely constant rated power. For this purpose, the rotor blades 108 are adjusted in their angular position relative to the hub 106 via the tilt system 110 so that the desired lift is generated. The tilt system 100 is further designed to prevent damage to the wind turbine 100 in strong winds by rotating the rotor blades 108 out of the wind, i.e., into the so-called feather position. This interrupts the lift of the rotor blade 108 and the rotor comes to a standstill.Of course, it is also possible that only one hydraulic tilt system 110 is provided, which adjusts the angles of all rotor blades 108.

[0032] In this exemplary embodiment, the tilt system 110 includes a hydraulic circuit 112 for extending and retracting a hydraulic actuator 114 in the form of a tilt cylinder. A hydraulic pump 116 is driven by an electric motor M to provide the pressurized hydraulic fluid. As shown in Fig. 2, a first valve 118 is provided upstream of the hydraulic pump 116 to connect the hydraulic pump 116 to either a piston side 120 or a rod side 122 of the tilt cylinder 114. The first valve 118 is designed as an electromagnetic proportional 4 / 3 spool valve. A check valve 124 is provided between the hydraulic pump 116 and the first valve 118 to prevent backflow to the hydraulic pump 116. The hydraulic circuit also includes a second electromagnetic valve 126 and a third electromagnetic valve 128 that bypasses the first valve 118. A hydraulic accumulator 130 is connected to the high-pressure side of the hydraulic pump 116. The hydraulic accumulator 130 is configured to compensate for the volume difference between the rod side 122 and the piston side 120 of the tilt cylinder 114.

[0033] In addition, a hydraulic device 10 is provided on the low-pressure side of the hydraulic pump 116. The hydraulic device 10 is also connected to the first valve 118 via a return line 132. As shown in Fig. 2, the third valve 128 is configured to bypass the first valve 118 and connect the rod side 122 directly to the return line 132.

[0034] The hydraulic device 10 comprises a reservoir 12 with a variable-capacity fluid reservoir 14 and an air space 16. In this exemplary embodiment, the reservoir is a bootstrap reservoir 12. The hydraulic device 10 further comprises an air separation device 18, which is designed to remove air from the hydraulic fluid. In the illustration shown, the air separation device 18 is arranged in the bootstrap reservoir 12. In particular, the bootstrap reservoir 12 comprises a housing 20, wherein the air separation device 18 is arranged in the housing 20 and is connected to the air space 16 via a pipe 22 and an air release valve 24. The bootstrap reservoir 12 and the air separation device 18 will now be described with reference to the Fig. 3 to 8 are explained in more detail.

[0035] A first piston 40 is movably arranged within the housing 20 of the bootstrap reservoir 12. The first piston 40 is connected to a second piston 42, which has a smaller diameter than the first piston 40. The first piston 40 separates the housing 20 into the variable-capacity fluid reservoir 14 and the air space 16. The first piston 40 is thus the accumulator piston of the bootstrap reservoir 12. The second piston 42 can be actuated via the hydraulic accumulator 30 (see Fig. 2) pressurized to move the first piston 40 to pressurize the hydraulic fluid contained in the variable-capacity fluid reservoir 14. Accordingly, the second piston 42 is the control piston of the bootstrap reservoir 12. The variable-capacity fluid reservoir 14 is connected to the hydraulic pump 116 on the low-pressure side via suction ports 46, so that the hydraulic pump 116 can be supplied with hydraulic fluid regardless of the orientation of the hub 106 and thus of the tilt system 110.

[0036] Hydraulic fluid flowing back from the tilt cylinder 114 via the first valve 118 and the return line 132 is returned to the bootstrap reservoir 12 and charged into the variable-capacity fluid accumulator 14. The entire hydraulic circuit 112 is controlled by a system controller (not shown) in a well-known manner using various input parameters, e.g., the pressure on the low-pressure side of the hydraulic pump 116, the pressure in the hydraulic accumulator 130, etc.

[0037] Although the Fig. Since the hydraulic circuit 112 shown in Figure 2 is designed as a closed hydraulic circuit during normal operation, air inevitably enters the hydraulic fluid, e.g., via the rod seals of the tilt cylinder, the piston seals of the bootstrap reservoir, the shaft seals of the pump, or during maintenance and replacement of components. To avoid negative effects on the performance of the hydraulic circuit 112, the air separation device 18 is provided.

[0038] The air separation device 18 is provided in the housing 20, and the hydraulic fluid flowing back via the return line 132 must first flow through the air separation device 18 before being charged into the variable-capacity fluid reservoir 14. The air separation device 18 consists of only one channel 34, which is wound around a central axis CA of the air separation device 18 or the bootstrap reservoir 12. As shown in the Fig. 7 and Fig. 8, the channel 34 winds in a plane around the central axis CA, thus forming a labyrinth-shaped liquid separator 26. As shown, the labyrinth-shaped liquid separator 26 is a coiled liquid separator. Of course, the labyrinth-shaped liquid separator 26 can also have a different shape, e.g., wound offset from the central axis CA or consisting of a tube with irregular turns. The only requirement is that the turns or loops all have the same winding direction, e.g., clockwise.

[0039] The radially outermost section of the labyrinth-shaped liquid separator 26 with respect to the central axis CA forms an air collection section 28. The radially innermost section of the labyrinth-shaped liquid separator 26 with respect to the central axis CA forms a liquid outlet section 32. A plurality of through holes 48 are provided at the liquid outlet section 32, which open into the variable-capacity liquid reservoir 14. A liquid inlet 30 connected to the return line 132 is provided between the air collection section 28 and the liquid outlet section 28. The air collection section 28 is connected to an air outlet 36 via the air discharge valve 24. The pipe 22 is connected to the air outlet 36 so that the air exiting the air separation device 18 is directed into the air space 16, as described in more detail below.In addition, a first detection sensor arrangement 38 is arranged in the air collection section 28 and a second detection sensor arrangement 44 is arranged in the air space 16.

[0040] The hydraulic fluid flowing back into the air separation device 18 via the fluid inlet 30 is an emulsion of hydraulic fluid and air, the latter of which is to be separated from the hydraulic fluid. Upon rotation of the bootstrap reservoir 12, and thus of the air separation device 18 together with the hub 106, about a rotational axis, the air is separated from the hydraulic fluid within the air separation device 18 due to gravity. As shown in Fig. As shown in Figure 9 (a), the hydraulic fluid enters the air separation device 18 via the fluid inlet 30, with the air being represented in this illustration by small circles or bubbles. The air separation device 18 is continuously rotated clockwise during operation of the wind turbine 100, so that the air tends to accumulate in the part of the spiral fluid separator 18 that points upwards, i.e., against the direction of gravity, see Fig.9(b) to 9(f), which illustrate the passage of air through the channel 34 of the labyrinth-shaped fluid separator 26 for several revolutions of the air separation device 18. In other words, since the air is lighter than the hydraulic fluid, the air collects in the portion of the spiral fluid separator 26 that faces upward against gravity. As the spiral fluid separator 26 continues to rotate, the air is guided along the channel 34 from the fluid inlet 30 to the air collection section 28.

[0041] Since the air collection section 28 is the radially outermost section of the convoluted fluid separator 26, the air tends to accumulate in the air collection section 28. Likewise, the hydraulic fluid then separated from the air tends to accumulate in the fluid outlet section 32 and is charged into the variable-capacity fluid reservoir via the plurality of through-holes 48.

[0042] The first detection sensor arrangement 38 is designed to detect the presence of air and liquid in the air collection section 28. In particular, the first detection sensor arrangement 38 can comprise a liquid detection sensor arranged in the immediate vicinity of the air outlet 36 and an air detection sensor arranged remotely from the liquid detection sensor in the air collection section 28, i.e., at the end of the air collection section 28. The air accumulating in the air collection section 28 displaces the hydraulic fluid in the air collection section 28 upon rotation of the air separation device 18. As soon as a certain amount of air has accumulated in the air collection section 28, the air detection sensor is no longer in contact with the hydraulic fluid, but with the air. The air detection sensor thus detects the presence of air, and the corresponding measurement signal is forwarded to the control system, which opens the air release valve 24.Due to the higher pressure of the hydraulic fluid in the air separation device 18, the air is then displaced from the air collection section 28 through the air outlet 36 and the hydraulic fluid fills the air collection section 28. As soon as the fluid detection sensor no longer comes into contact with air but with hydraulic fluid, a corresponding measurement signal is sent to the control system, which then closes the air discharge valve 24 and the accumulation of air in the air collection section 28 begins again.

[0043] Since hydraulic fluid may escape through the air outlet 36, the air outlet 36 is connected to the air space 16 via the pipe 22. As a result, the hydraulic fluid does not enter the hub 106, but rather the air space 16. In the event of a malfunction, e.g., of the air release valve 24, a larger quantity of hydraulic fluid is released into the air space 16. The presence of hydraulic fluid in the air space 16 is then detected by the second detection sensor arrangement 44 arranged in the air space 16, and a corresponding measurement signal is generated and reported to the control system. Appropriate countermeasures can then be taken, such as an emergency shutdown of the wind turbine 100.

[0044] The air space 16 may be connected to the environment via an air filter designed to withstand a certain amount of hydraulic fluid, since even during normal operation of the tilt system 110, small amounts of hydraulic fluid may enter the air space 16 via the pipe 22.

[0045] Since the air separation device 18 is provided on a cover of the housing 20 of the bootstrap reservoir 12, the air separation device 18 can also be retrofitted to existing bootstrap reservoirs 12. LIST OF REFERENCE SYMBOLS 10 Hydraulic device 12 reservoir / bootstrap reservoir 14 Capacity variable liquid storage 16 Airspace 18 Air separation device 20 housings 22 pipe 24 Air release valve 26 liquid separators 28 Air collection section 30 Liquid inlet 32 Liquid outlet section 34 channel 36 Air outlet 38 First detection sensor arrangement 40 First piston 42 Second piston 44 Second detection sensor arrangement 46 Suction connection 48 through hole 100 wind turbines 102 Tower 104 gondolas 106 Rotor / Hub 108 rotor blades 110 tilt system 112 Hydraulic circuit 114 Hydraulic actuator / tilt cylinder 116 Hydraulic pump 118 First valve 120 piston side 122 rod side 124 Check valve 126 Second valve 128 Third valve 130 hydraulic accumulators 132 Return line CA central axis M engine QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2015 / 014367 A1

[0007]

Claims

[1] A hydraulic device (10) for a tilt system (110) of a wind turbine (100), comprising an air separation device (18), wherein the air separation device (18) has a liquid separator (26) with an air collection section (28), at least one liquid inlet (30), and a liquid outlet section (32), wherein a liquid emulsion of air and hydraulic fluid can be introduced into the liquid separator (26) through the at least one liquid inlet (30), wherein the liquid separator (26) is labyrinth-shaped, such that rotation of the air separation device (18) about an axis of rotation causes the air in the liquid emulsion to move through the labyrinth-shaped liquid separator (26) in a direction toward the air collection section (28), and the hydraulic fluid in the liquid emulsion to move through the labyrinth-shaped liquid separator (26) in a direction toward the liquid outlet section (32). [2] Hydraulic device (10) according to claim 1, characterized by , that the hydraulic device (10) further comprises a reservoir (12) with a variable-capacity liquid storage (14), wherein the labyrinth-shaped liquid separator (26) is wound around an axis (CA), the air collection section (30) being the radially outermost section of the labyrinth-shaped liquid separator (26), wherein the liquid outlet section (32) is arranged radially inward of the air collection section (28), and wherein the at least one liquid inlet (30) is arranged between the liquid outlet section (32) and the air collection section (28), wherein the liquid outlet section (32) is connected to the variable-capacity liquid reservoir, and wherein the axis is preferably a central axis (CA). [3] Hydraulic device (10) according to claim 1 or 2, characterized bythat the labyrinth-shaped liquid separator (26) comprises a channel (34) which is wound around the central axis (CA) in preferably one plane. [4] Hydraulic device (10) according to one of the preceding claims, characterized by that the liquid outlet section (32) comprises at least one through-hole (48), wherein the at least one through-hole (48) is preferably connected to the variable-capacity liquid reservoir. [5] Hydraulic device (10) according to one of the preceding claims, characterized by that the hydraulic device (10) further comprises an air outlet (36) and an air discharge valve (24), wherein the air collection section (28) is connected to the air outlet (36) via the air discharge valve (24). [6] Hydraulic device (10) according to claim 5, characterized bythat a first detection sensor arrangement (38) is arranged in the air collection section (28), wherein the opening and closing of the air discharge valve (24) is controlled via measurement signals of the first detection sensor arrangement (38). [7] Hydraulic device (10) according to one of the preceding claims 2 to 6, characterized by that the reservoir (12) comprises a housing (20) and a piston (40) movably arranged in the housing (20), wherein the piston (40) separates the housing (20) into the capacity-variable liquid reservoir and an air space (16), wherein the reservoir (12) is preferably a bootstrap reservoir. [8] Hydraulic device (10) according to claim 7, characterized by that the air separation device (18) is arranged in the housing (20). [9] Hydraulic device (10) according to claim 7 or 8, characterized by that the air collection section (28) is connected to the air space (16). [10] Hydraulic device (10) according to claim 9, characterized by that a second detection sensor arrangement (44) is arranged in the air space (16). [11] Tilt system (110) for a wind turbine (100), comprising at least one hydraulic actuator (114), a hydraulic pump (116), a hydraulic accumulator (130) and a hydraulic device (10) according to one of the preceding claims, wherein the hydraulic device (10) is connected to the hydraulic accumulator (130) and the hydraulic pump (116), wherein the hydraulic pump (116) is designed to drive the hydraulic actuator (114) and to charge the hydraulic accumulator (130). [12] Wind turbine (100) comprising a nacelle (104), a hub (106) rotatably mounted on the nacelle (104), at least one rotor blade (108) mounted on the hub (106), and at least one inclination system (110) according to claim 11, wherein the at least one inclination system (110) is arranged in the hub (106), and wherein the at least one inclination system (110) is designed to adjust an inclination angle between the at least one rotor blade (108) and the hub (106).

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