SEALING SYSTEM FOR UNDERWATER TURBINE

Description

[0001] The present invention relates to a sealing system for sealing a shaft of an underwater turbine according to the preamble of claim 1.

[0002] Underwater turbines, particularly in marine applications such as tidal power plants, are typically sealed against the surrounding water, especially seawater, using sealing systems. In particular, the bearing assemblies that flexibly connect the individual parts of the underwater turbine must be reliably sealed against water ingress. At the same time, seals must prevent external elements such as dust, abrasion, particles, water, and marine species like plankton and algae from penetrating the bearing assemblies and damaging their components. Particles can also penetrate the seals themselves, reducing their service life.

[0003] Typically, several adjacent seals are provided to create a redundant sealing system, whereby the lips of the adjacent seals may also be oriented in different directions. Known sealing systems are disclosed in DE 102013 008 967 A1, DE 37 18411 A1, EP 3 591 245 A1 and DE 10 2011 016 185 A1.

[0004] However, the pressures prevailing in water exert high forces on seals and the sliding surfaces in contact with them, which can lead to mutual wear of these components within a short time and thus impair the sealing effect. Replacement can be complex or expensive, and may not always be possible.

[0005] In particular, the seals may not be replaceable underwater. Therefore, such maintenance procedures can be expensive and require the underwater turbine to be shut down frequently and for extended periods.

[0006] It is therefore an object of the present invention to provide a sealing system for an underwater turbine in which the wear of the seals is reduced and the maintenance process is simplified.

[0007] This problem is solved by a sealing system according to claim 1.

[0008] The following proposes a sealing system for an underwater application, particularly a marine application. This sealing system is specifically designed for sealing a rotatable component, such as a shaft or an underwater turbine, especially an underwater turbine of a tidal power plant. The sealing system comprises several annular sealing carriers arranged adjacent to one another. Each sealing carrier supports at least one sealing element with an annular sealing body and at least one sealing lip extending from the sealing body. The sealing body is attached to the sealing carrier, and the sealing lip extends towards the shaft to be sealed. The sealing element itself is preferably a seawater seal, i.e., a sealing element suitable for sealing against seawater.Furthermore, the sealing lip has a running surface with which it contacts a counter-running surface formed directly or indirectly on the rotatable component. This counter-running surface can be formed directly by the rotatable component itself, such as the shaft, or indirectly by a thrust element, such as a thrust sleeve, which is fixed to the rotatable component in a rotationally fixed manner.

[0009] To minimize wear on the sealing system and the mating surface, a space is provided between the seal carrier and the rotating component, forming a chamber that holds a lubricant. For this purpose, the seal carrier can, for example, have a recess open towards the shaft, forming the chamber. The lubricant in the chamber reduces friction between the sealing lip and the mating surface, which in turn reduces wear. Furthermore, the lubricant protects the internal seal carrier rings from corrosion. Preferably, the lubricant is a grease. According to another preferred embodiment, at least the sealing lip, and preferably the entire sealing element, is made of a material with friction-reducing properties.In particular, the sealing lip can be made of a material in which a solid lubricant is embedded or which forms a solid lubricant. It is also possible that a friction-reducing material is applied to the sealing lip, especially to the running surface, for example by means of a suitable coating. This allows for a low-friction sealing system that provides a low-friction seal even without the presence of lubricant, for example, after the lubricant has been used up or aged.

[0010] To further simplify maintenance, the sealing system also features a sealing carrier designed as a mounting seal carrier, wherein the mounting seal carrier is designed to be attached to a stationary component of the tidal system, in particular to a bearing ring of a bearing unit supporting the shaft to be sealed or to a housing accommodating the bearing unit. Furthermore, the mounting seal carrier has at least one annular groove on an end face facing the stationary component, which is designed to accommodate a static seal, in particular an O-ring seal.Furthermore, the fastening sealing carrier has a bore which has a first radially extending bore part and a second axially extending bore part, wherein the axially extending bore part extends from the first bore part to the end face facing the stationary component, so that the second bore part opens radially into the end face within the annular groove.

[0011] Alternatively or additionally, the sealing system has a starting sleeve that forms a counter-running surface for the multiple sealing lips, wherein the starting sleeve has at least one annular groove on its inner surface designed to receive a static seal, in particular an O-ring seal. Furthermore, a bore is provided in the starting sleeve, comprising a first axially extending bore section and a second radially extending bore section, wherein the radially extending bore section extends from the first bore section to the inner surface, so that the second bore section opens into the inner surface behind the annular groove in the axial sealing direction.

[0012] These bores in the mounting seal carrier or in the starting sleeve can be used, among other things, to test the sealing capacity of the static seals (O-rings). For this purpose, a test fluid can be introduced into the respective bore and subjected to a predetermined pressure, up to which the static seal is expected to provide a minimum seal.

[0013] In addition, a lubricant, in particular an oil, can be introduced into the bore formed in the starting sleeve to allow axial displacement of the starting sleeve. This lubricant adheres to the contact surface between the starting sleeve and the rotatable component and facilitates the axial displacement of the starting sleeve.

[0014] In a further preferred embodiment, a recess open towards the rotatable component is formed in the seal carrier, forming the chamber. This chamber-forming recess is dimensioned and arranged such that a free space remains between the side of the sealing lip facing away from the running surface and the seal carrier, forming the chamber that can be supplied with lubricant. It is particularly preferred that the recess is designed as a sealing lip receiving recess, surrounding and receiving a sealing lip, with the free space between the sealing lip and the recess forming the chamber. This design allows the lubricant to enhance the sealing effect of the sealing lip by increasing the contact pressure of the sealing lip on the counter-running surface.This design also ensures that the water pressure is balanced by the lubricant pressure at the first sealing lip that seals against water, which in turn reduces wear.

[0015] To further reduce wear in this design, lubricant can also be applied to the same side of the sealing lip's running surface, so that the sealing lip is not subjected to additional pressure with respect to the lubricant. In this preferred embodiment, the lubricant acts as an additional barrier against the ingress of seawater, since the water must displace the lubricant to penetrate into and through the sealing system.

[0016] According to a further preferred embodiment, the seal carrier has at least one, preferably radial, through-bore that is fluidically connected to the chamber. Lubricant can be introduced into the chamber through this through-bore. The bore can also be used to remove any water that has penetrated the sealing system. Furthermore, the bore can be used to test the sealing capacity of the sealing lip after the sealing system has been installed in the underwater turbine. For this purpose, a vacuum can be applied to the through-bore, or a test fluid can be introduced to test for leaks under, for example, negative or positive pressure.

[0017] It is also advantageous if a sensor is arranged in the through-bore or in the chamber that detects an ingress of water into the chamber or into the bore and can preferably transmit this information to a monitoring system.

[0018] It is further preferred that the sealing carrier has two radial through-bores that are fluidically connected to the chamber, the two radial bores being arranged offset from each other by 180°. Since the sealing system is usually designed to be completely airtight, air that must escape when the lubricant is introduced into the chamber cannot escape through the sealing system, or only with great difficulty. By providing a second bore, the air displaced by the lubricant can be expelled from the sealing system, so that the chamber and the through-bores are filled with lubricant. The preferred 180° arrangement also ensures that the lubricant can spread evenly and without bubbles in the chamber and in the bores.

[0019] According to a further preferred embodiment, the radial bore has a first radially outer thread and a second radially inner thread, the first thread having a larger diameter than the second thread. Such a design allows for a redundant closure option for the bore, ensuring that no water can penetrate the sealing system through the bore. It is particularly preferred that the second thread is designed to receive a setscrew, preferably tapered, which is held in the thread in a sealing manner, while the first thread is closed with a screw-in plug that provides a sealing seal.

[0020] According to a further preferred embodiment, each sealing carrier has at least one recess for receiving the sealing element, designed to accommodate the sealing element in a rotationally fixed manner. This recess is preferably open to an end face of the annular sealing carrier and has an axial depth that is less than the height of the sealing element. When an elastomeric sealing element is used, this design ensures that the elastomeric deformation during installation of the sealing system presses the contact surfaces of the sealing element against the contact surfaces in the recess of the sealing carrier and against an adjacent element, thus creating a sealing effect. This also provides a static seal between the sealing carriers.

[0021] Alternatively or additionally, the sealing carrier can have at least one annular groove on at least one end face, designed to accommodate a static seal, in particular an O-ring seal.

[0022] Preferably, the sealing element receiving recess and the sealing lip receiving recess are arranged axially spaced apart from each other at two axial ends of the sealing carrier. This enables a preferred embodiment in which the sealing lip receiving recess is designed to receive the sealing lip of a sealing element supported by an adjacent sealing carrier.

[0023] It is further preferred if the recess is designed in such a way as to provide support for the sealing lip and radial support for the sealing body. The support for the sealing lip ensures that the sealing lip cannot "fold over" due to the pressure acting upon it. The support for the sealing body enables radial support or retention of the sealing body in the direction of the rotating component. For this purpose, corresponding support elements can be formed on the sealing carrier.

[0024] According to a further preferred embodiment, at least one sealing carrier, preferably radially internal, has an annular, axially projecting extension designed to engage with a complementary annular axial indentation of an adjacent sealing carrier. This enables self-centering of the individual sealing carriers. Furthermore, the engagement of the extension in the indentation provides an additional barrier against water ingress.

[0025] It is particularly preferred if the annular projection defines an axial depth of a circumferential contact surface of the sealing body receiving recess for a radially outer circumferential surface of the annular sealing body.

[0026] According to a further preferred embodiment, the at least one sealing carrier has several circumferentially distributed, preferably threaded, mounting holes on its radially outer edge region, which are designed to accommodate a fastener for securing the sealing carrier and / or a removal screw for disassembling the sealing carrier. Because of the high tightening pressure required to ensure that the sealing carrier and its counterpart fit together as watertight as possible, and because of contamination and potential corrosion, the two parts can "bake" together after prolonged use, they often cannot be separated without damage, for example, to service a sealed bearing or to replace the entire sealing system.The possibility of screwing a pressure-relieving screw into the seal carrier allows the seal carrier to be pressed away from the counterpart and thus easily removed.

[0027] If several sealing carriers are provided, each with multiple circumferentially distributed mounting holes on its radially outer edges, it is further preferred that the sealing carriers have different outer diameters, the outer diameters being dimensioned such that the mounting holes located on the radially outer edges are freely accessible when the sealing system is installed. This allows for the accessibility and replaceability of individual components of the sealing system without having to remove the entire sealing system from the stationary component. This also allows the sealing system to be serviced underwater.

[0028] Furthermore, an exemplary embodiment is advantageous in which the sealing system comprises a sealing carrier designed as a mounting seal carrier, wherein the mounting seal carrier is designed to be attached to a stationary component of the tidal system, in particular to a bearing ring of a bearing unit supporting the shaft to be sealed or to a housing accommodating the bearing unit. It is further advantageous if the mounting seal carrier has at least one annular groove on an end face facing the stationary component, which is designed to accommodate a static seal, in particular an O-ring seal. This ensures that water cannot penetrate into the underwater turbine even past the sealing system.

[0029] Preferably, a second annular groove is also provided radially within the first groove, which is likewise designed to accommodate a static seal, in particular an O-ring seal. This creates redundancy at this sealing point as well, reliably preventing water from penetrating the underwater turbine.

[0030] According to a further preferred embodiment, the mounting seal carrier has a bore comprising a first radially extending bore section and a second axially extending bore section. The axially extending bore section extends from the first bore section to the end face facing the stationary component, so that the second bore section opens radially within the first, and preferably radially outside the second annular groove, into the end face. This bore, like the chamber-connecting bores mentioned above, can be used to test the sealing capability of the static seal. For this purpose, a test fluid can be introduced into this bore and pressurized, for example, to a predetermined pressure up to which the static seal is expected to provide a minimum seal.

[0031] According to a further preferred embodiment, the mounting seal carrier has several circumferentially distributed, preferably threaded, mounting holes on its radially outer edge region. These holes are designed to accommodate a fastener for attaching the mounting seal carrier to the stationary component and / or a release screw for removing the mounting seal carrier from the stationary component. Because of the high tightening pressure required to ensure a watertight seal between the mounting seal carrier and the stationary component, and due to contamination and potential corrosion, the two parts can "bake" together after prolonged use. Therefore, they often cannot be separated without damage, for example, to service a sealed bearing or to replace the entire sealing system.The possibility of screwing a pressure-off screw into the mounting seal carrier allows the seal carrier to be pressed away from the stationary component and thus be easily removed.

[0032] Furthermore, it is preferred that the mounting seal carrier has an outer diameter that is larger than the outer diameters of the other seal carriers, wherein the outer diameters are preferably dimensioned such that the mounting holes arranged in the radially outer edge region are freely accessible when the sealing system is installed. This allows the sealing system to be attached to and removed from the stationary component as a complete unit without having to disassemble the sealing system into its individual parts. This also makes it possible to test the sealing capacity of the sealing system before installation.

[0033] On the side facing away from the mounting seal carrier and thus on the side facing away from the stationary component, i.e., towards the surrounding water, the sealing system preferably further comprises a sealing carrier designed as a cover seal carrier, wherein the cover seal carrier is designed to cover the sealing system from the external environment. This cover seal carrier may, instead of a seawater seal, only have a particle seal designed to prevent external elements, such as dust, abrasion, particles, and marine species, such as plankton and algae, from penetrating the sealing system.

[0034] Analogous to the fastening sealing carrier, the cover sealing carrier may preferably also have several circumferentially distributed, preferably threaded, fastening bores on its radially outer edge area, which are designed to accommodate a fastening means for attaching the fastening sealing carrier to an adjacent or a further sealing carrier and / or a release screw for dismantling the cover sealing carrier from the adjacent sealing carrier.

[0035] Advantageously, the cover seal carrier has an outer diameter that is smaller than the outer diameter of at least one other seal carrier. This ensures that the cover seal carrier, when installed, does not restrict access to the other seal carriers.

[0036] According to a further preferred embodiment, at least one first sealing carrier and one second additional sealing carrier are provided between the mounting sealing carrier and the cover sealing carrier, wherein the first sealing carrier is adjacent to the mounting sealing carrier and the second sealing carrier is adjacent to the cover sealing carrier. This provides sufficient redundancy so that even if one sealing element fails, further sealing elements are present to prevent water from penetrating the underwater turbine. The number of additional sealing carriers can depend on the application. For example, the number of sealing lips depends on the expected water pressure and / or service life.

[0037] Analogous to the fastening seal carrier and the cover seal carrier, it is advantageously also provided that the first seal carrier has several circumferentially distributed, preferably threaded, fastening bores on its radially outer edge region, which are designed to accommodate a fastening means for attaching the first seal carrier to the fastening seal carrier and / or a release screw for removing the first seal carrier from the fastening seal carrier, and / or the second seal carrier has several circumferentially distributed, preferably threaded, fastening bores on its radially outer edge region, which are designed to accommodate a fastening means for attaching the second seal carrier to the first seal carrier and / or a release screw for removing the second seal carrier from the first seal carrier.

[0038] Alternatively, the second sealing carrier may not have its own screw connection, but rather the mounting openings may be designed to accommodate the fasteners of the cover sealing carrier, so that the second sealing carrier and the cover sealing carrier are screwed together to the mounting sealing carrier. The option of screwing in a pressure-reducing screw may also be provided separately for the second sealing carrier in this embodiment.

[0039] As mentioned above, this allows the sealing system to be attached to the stationary component as a single unit, and also enables individual components of the sealing system to be replaced without having to remove the entire sealing system from the stationary component. This also allows the sealing system to be serviced underwater.

[0040] According to a further preferred embodiment, at least the first sealing carrier has an outer diameter that is larger than the outer diameter of the second sealing carrier, wherein the outer diameters are preferably dimensioned such that the mounting holes arranged in the radially outer edge region are freely accessible when the sealing system is installed. This also allows for the accessibility and replaceability of individual components of the sealing system without having to remove the entire sealing system from the stationary component. This also allows the sealing system to be serviced underwater.

[0041] If the second sealing carrier and the cover sealing carrier are designed to be mounted together, it is advantageous if their outer diameters are the same.

[0042] As mentioned above, the sealing lips of the sealing system run against a counter-running surface. This counter-running surface can be formed by the rotating component itself; however, since the running of the sealing lips can cause wear, in particular the formation of grooves on the counter-running surface, it is preferable, especially when sealing shafts, to use a thrust sleeve that is fixed to the rotating element, in particular the shaft, in a rotationally fixed manner.

[0043] One particularly advantageous embodiment involves pressing the thrust sleeve onto the shaft. The advantage of this press fit is that the thrust sleeve can be designed to be significantly more compact, as a flange for securing the sleeve is no longer required. Furthermore, this results in lower costs, since a material- and labor-intensive design involving a flange and screws is eliminated.

[0044] To seal the underwater turbine against water ingress along the starting sleeve, the starting sleeve preferably has at least one annular groove on its inner surface, designed to accommodate a static seal, in particular an O-ring seal. Preferably, a second annular groove is also provided, offset axially towards the stationary component compared to the first groove, and likewise designed to accommodate a static seal, in particular an O-ring seal. This creates redundancy at this sealing point as well, reliably preventing water from entering the underwater turbine.

[0045] The thrust sleeve can be designed to be axially displaceable, so that the sealing lips engage at an axially offset point after maintenance. This eliminates the need to completely remove the thrust sleeve from the shaft or rotating component, which is a time-consuming and complicated maintenance procedure.

[0046] To facilitate axial displacement of the pressed-on thrust sleeve, a bore is provided in the thrust sleeve. This bore comprises a first axially extending section and a second radially extending section. The radially extending section extends from the first section to the inner surface of the sleeve, so that, in the installed state, the second section opens into the inner surface between the stationary component and the annular groove, preferably between the first and second annular grooves. The opening is preferably located centrally within the thrust sleeve. A lubricant, particularly oil, can be introduced into this bore to facilitate axial displacement. This lubricant adheres to the contact surface between the thrust sleeve and the rotating component, thus facilitating axial movement.

[0047] At the same time, this bore can also be used to test the sealing capacity of the static seal. For this purpose, as described above, a test fluid can be introduced, which is then subjected to a predetermined pressure up to which the static seal is expected to remain sealed.

[0048] According to a further preferred embodiment, the starting sleeve has at least one second bore comprising a first axially extending bore section and a second radially extending bore section, the radially extending bore section reaching from the first bore section to the outer surface of the sleeve. This second bore is fluidically connected to one of the lubricant-receiving chambers of the sealing system. Lubricant can also be introduced into the chamber via this through-bore through the starting sleeve. Furthermore, the bore can be used to remove any water that has penetrated the sealing system. Additionally, the bore in the starting sleeve can also be used to test the sealing capability of the sealing lip after the sealing system has been installed in the underwater turbine. For this purpose, a vacuum can be applied to the through-bore, for example, or a test fluid can be introduced.

[0049] It is also advantageous if a sensor is arranged in the through-bore or in the chamber that detects an ingress of water into the chamber or into the bore and can preferably transmit this information to a monitoring system.

[0050] Analogous to the sealing carrier, it is also preferred for the starting sleeve to have two secondary through-bores that are fluidically connected to the chamber, with the two secondary bores preferably offset from each other by 180°. Since the sealing system is usually designed to provide a complete seal, air that must escape when the lubricant is introduced into the chamber cannot escape through the sealing system, or only with great difficulty. By providing an offset bore, the air displaced by the lubricant can be expelled from the sealing system, so that the chamber and the through-bores are filled with lubricant. The preferred 180° arrangement also ensures that the lubricant can spread easily and without bubbles in the chamber and in the bores.

[0051] Furthermore, an exemplary embodiment is advantageous in which all chambers of the sealing system are connected via bores in the starting sleeve for the introduction of a lubricant or test fluid, or for the application of a vacuum, whereas no bores are provided in the sealing carriers. In this exemplary embodiment, an inlet and an outlet can also be provided – that is, another centrally located axial bore with corresponding branches, preferably offset by 180°.

[0052] According to a further preferred embodiment, the at least one bore in the guide sleeve has a first axially external thread and a second axially internal thread, wherein the first thread has a larger diameter than the second thread. Such a design allows for a redundant sealing option for the bore, thus ensuring that no water can penetrate the sealing system through the bore. It is particularly preferred that the second thread is designed to receive a, preferably tapered, setscrew that can be screwed into the inner second thread to create a seal, while the first thread is closed with a sealing screw-in plug.

[0053] According to a further preferred embodiment, a sacrificial anode is attached to the sealing system, in particular to the cover sealing carrier, which protects the sealing system from corrosion.

[0054] It is particularly preferred if the sacrificial anode is attached to the optionally fitted starting sleeve and / or to the cover seal carrier. The sacrificial anode can also be attached to the starting sleeve via a spacer element, whereby the spacer element reduces the distance to another component arranged on the shaft, such as a rotor or rotor blade, thus ensuring that the axial displacement of the starting sleeve is limited. With the press-fitted starting sleeve, this ensures that the starting sleeve does not shift on the shaft due to aging, such as material and age-related expansion.

[0055] The sealing system can be used at various points on the underwater turbine. It is particularly preferred for use on a pitch system for adjusting the rotor blade position, for a main shaft seal between the rotor shaft and the nacelle, and / or a yaw system for rotating the nacelle.

[0056] The bearing units that support the rotating component, especially the shaft, and which can be sealed using the sealing system, can be rolling bearings or plain bearings. They can also form a rotary joint for the rotation of the rotor blade or nacelle.

[0057] According to a preferred embodiment, the sealing system is installed on the pivoting system for the rotor blades mounted on a rotor hub. It is particularly advantageous if the bearing arrangement is not designed as a pivot bearing with a massive and large outer bearing ring, but rather as a bearing arrangement with two spaced-apart bearing units. In this configuration, the rotor hub serves as the bearing housing, and the sealing system is mounted directly on the rotor hub and not, as in the prior art, on the outer bearing ring of the pivot bearing. While the rotor hub itself is not a stationary component, it is stationary with respect to the rotation of the rotor blade. The shaft bearing arrangement can be designed, for example, as a combination of a floating and a fixed bearing, or as a combination of two tapered roller bearings.

[0058] Another aspect of the present invention relates to a bearing arrangement for an underwater turbine, in particular a tidal turbine, which has a sealing system as described above.

[0059] Another aspect of the invention relates to an underwater turbine with a sealing system described above.

[0060] Further advantages and advantageous embodiments are specified in the description, the drawings, and the claims. In particular, the combinations of features specified in the description and the drawings are purely exemplary, so that the features may also exist individually or in different combinations.

[0061] The invention will now be described in more detail with reference to exemplary embodiments illustrated in the drawings. These exemplary embodiments and the combinations shown in them are purely illustrative and do not define the scope of protection of the invention. The scope of protection is defined solely by the appended claims.

[0062] They show: Fig. 1: a first sectional view through a preferred embodiment of a sealing system; Fig. 2: a second sectional view through the preferred embodiment of the sealing system made of Fig. 1 Fig. 3: a third sectional view through the preferred embodiment of the sealing system made of Fig. 1 ; and Fig. 4: a fourth sectional view through the preferred embodiment of the sealing system made of Fig. 1 .

[0063] In the following, identical or functionally equivalent elements are marked with the same reference symbols.

[0064] The Figures 1 to 4 The figures show various sectional views through different planes of a preferred embodiment of a sealing system 100 for sealing a rotatable component of an underwater turbine. In the figures shown, the sealing system 100 is designed for sealing a bearing of a rotatable rotor blade. However, the sealing system 100 can be used for all types of seals, such as a main rotor shaft bearing or a bearing for rotating a nacelle.

[0065] In the embodiment shown in the figures, the sealing system 100, as mentioned above, is designed to support a rotor blade shaft 2, to which rotor blades 4 are fixedly attached. The rotor blade shaft 2, in turn, is rotatably mounted in a rotor hub 6, with bearing arrangements 8 provided for this purpose. Rolling bearings or plain bearings can be used as bearing units. The bearing units 8 shown schematically here as rolling bearings are merely placeholders for any bearing type.

[0066] The sealing system 100 in turn has several ring-shaped sealing carriers 20-1, 20-2, 20-3, 20-4. Each sealing carrier 20 is designed to carry at least one dynamic sealing element 30, wherein the sealing elements 30 are arranged in associated sealing body receiving recesses 21 formed on the respective sealing carriers 20.

[0067] The dynamic sealing elements 30 show, as shown in the detailed view of Fig. 1a Each sealing element 30 comprises a sealing body 32 and a sealing lip 34, wherein the sealing body 32 is annular and is received in the recess 21, while the sealing lips 34 extend radially inwards towards the shaft 2. Furthermore, the sealing elements 30 have a running surface 36 with which they contact a counter-running surface 42. In this illustrated embodiment, the counter-running surface 42 is formed by a thrust sleeve 40; however, it is also possible that the sealing lips 34 bear directly against the shaft 2.

[0068] Furthermore, it shows Fig. 1aThe sealing carrier 20 has a first support element 37 and a second support element 38, which are designed to support and carry the sealing lip or the sealing body 32. The support element 37 is designed to support the sealing lip 34 and, even under high water pressure, to prevent the sealing lip 34 from "folding over," i.e., bending towards the side to be sealed. The support element 38 serves to support the sealing body 32 radially on the inside and, together with the adjacent sealing carrier, to create a tight receiving space for the sealing body 32, so that the sealing body 32 is held in the sealing system in a rotationally fixed and statically sealing manner.

[0069] In order to form the most compact sealing system possible, sealing lip receiving recesses 22 are further formed on the sealing carriers, which can receive a sealing lip of a sealing element supported by the sealing carrier itself (see sealing carrier 20-3 and 20-4) or a sealing lip of a sealing element supported by an adjacent sealing carrier (see sealing carrier 20-1 and 20-2).

[0070] As can be seen further in the exemplary embodiment, the sealing system incorporates various dynamic sealing elements 30, each fulfilling different sealing tasks. Sealing element 30-1 is designed as a particle seal, preventing contaminants from entering the sealing system 100. Seals 30-2 to 30-4, on the other hand, are designed as so-called seawater seals and feature sealing lip geometries and materials that prevent water from entering the rotor hub 6. For this purpose, the sealing lips 34 of the seawater seals are directed, in particular, towards the rotor blade 4.

[0071] The sealing element 30-5, on the other hand, serves to retain lubricant used in the bearing unit 8 within the bearing unit 8 and to prevent it from escaping from the bearing unit into the sealing system 100. For this reason, the sealing lip 34-5 of the sealing element 30-5 is directed towards the bearing unit 8. The sealing body receiving recess 21 can be designed as a groove 21-1, as shown for the sealing carrier 20-1, but it can also be designed as a recess open towards the end face, as shown for the sealing carriers 20-2 to 20-4.

[0072] In the illustrated embodiment, the sealing carrier 20-1 is designed as a cover sealing carrier, while the sealing carrier 20-4 is designed as a mounting sealing carrier, which in the illustrated embodiment is attached directly to the rotor hub 6. Depending on the design of the bearing unit 8, the mounting sealing carrier can also be attached directly to a bearing ring.

[0073] As mentioned above, the sealing carriers 20 have recesses 22 designed to receive either their own or an adjacent sealing lip 34. In the illustrated embodiment, the sealing lip 34-2 of the second sealing element 30-2 is received in the recess 22-1, and the sealing lip 34-3 of the sealing element 30-3, which is supported by the third sealing carrier 20-3, is received in the recess 22-2.

[0074] The recesses 22-3 and 22-4, on the other hand, are designed to receive sealing lips of a sealing element supported by the same sealing carrier. Thus, the sealing carrier 20-3 supports both the sealing body 32-4 of the sealing element 30-4 and simultaneously has a recess 22-3 in which the sealing lip 34-4 of the same sealing element 30-4 is received. The same applies to the sealing carrier 20-4.

[0075] In the Figures 1-3 The illustrated embodiment further shows that fastening holes 23 are provided on the sealing carriers 20 in a radially outer edge region. The fastening holes are designed such that they are either for receiving a fastening element, in particular a screw 50, (see Fig. 1 and Fig. 3 ) or a so-called pressure-reducing screw 52 (see Fig. 2) are designed. A thread 24 can be provided in the opening for this purpose, but it is also possible for the opening to be a smooth bore. Preferably, no thread is provided in the mounting bores 23, which are intended for receiving a screw 50, but only in the mounting bores 23 that serve to receive the ejector screw 52.

[0076] In the sectional view shown, the Figure 2 Only the cover sealing carrier 20-1 and the fastening sealing carrier are equipped with a pressure-reducing screw 52. However, this can also be provided on the sealing carriers 20-2 and 20-3 arranged between them.

[0077] The release screws 52 serve to detach the respective seal carrier 20 from its fastening partner, in this case the rotor hub 6 or the seal carrier 20-3. Since the connection between the seal carriers 20 and their respective fastening partners becomes so tight after a certain period of time, damage-free removal of the seal carrier rings for maintenance purposes is often impossible. However, the release screws 52 allow the seal carrier 20 to be detached from its respective fastening partner without damage. The release screw 52 is screwed into the thread 24, with the release screw 52 itself having a longer axial length than the seal carrier 20 itself, so that the release screw 52 abuts the other fastening partner and, upon further tightening, pushes the seal carrier 20 away from the respective fastening partner.

[0078] Furthermore, the figures show that the sealing carrier 20-2 is screwed to the adjacent sealing carrier 20-3 with the aid of the cover sealing carrier 20-1. Of course, it would also be possible to screw the sealing carrier 20-2 on independently. The exemplary embodiment also shows that the mounting holes are provided in a radially outer edge region of the sealing carriers 20. It should also be noted that the sealing carrier 20-2 and the sealing carrier 20-3 can not only be screwed to the adjacent sealing carriers 20-3 and 20-4, respectively, but can also be attached to another element across one or more sealing carriers. However, the embodiment shown here has the advantage that the sealing system 100 can be screwed directly onto the rotor hub 6 as a prefabricated unit.

[0079] Furthermore, the figures show that the mounting seal carrier 20-4 has the largest outer diameter, while the adjacent seal carriers 20-3, 20-2, and 20-1 have smaller outer diameters. This allows the mounting holes 23, located in the radial outer region of the respective seal carriers 20, to remain freely accessible even when installed. Similarly, the outer diameter of the adjacent seal carrier 20-3 is moderately larger than that of the adjacent seal carrier 20-2.

[0080] In the illustrated embodiment, the sealing carrier 20-2 and the cover sealing carrier 20-1 have the same outer diameter and are attached together to the first sealing carrier 20-3. Of course, it would also be possible to provide a step between the second sealing carrier 20-2 and the cover sealing carrier 20-1, and also to attach the sealing carrier 20-2 separately to the sealing carrier 20-3.

[0081] Furthermore, the Figures 1-3, that static seals 54, 55 in the form of, for example, O-rings are arranged for sealing between the rotationally fixed elements, namely between the mounting seal carrier 20-4 and the rotor hub 6, and between the thrust sleeve 40 and the shaft 2. For this purpose, the mounting seal carrier 20-4 has annular grooves 25 into which O-rings 54 can be inserted. Similarly, the thrust sleeve 40 has grooves 44 into which the O-rings 55 can be inserted (see in particular ). Fig: 2 and 3 ). Such static seals can also be provided on the other sealing carriers.

[0082] To further protect the sealing system 100 from corrosion, a sacrificial anode 56 is also provided, which is arranged adjacent to the sealing system 100 and the starting sleeve 40. Furthermore, [the figure] shows Figure 1 , that the sacrificial anode 56 is separated from a spacer element 58 (see Fig. 3) is supported, which is dimensioned such that the distance between spacer element 58 and rotor blade 4 is minimized. This ensures that the starting sleeve 40 has only limited axial play, which in turn prevents unwanted axial displacements and thus a deterioration of the sealing properties. This provides the preferred redundancy, especially for the starting sleeve installed under a press fit.

[0083] To minimize wear on the sealing lips 34 and the starting sleeve 40, a friction-free starting condition between the sealing lip 34 and the counter-running surface 42 must be created. For this purpose, the sealing lips 34, or more generally the sealing element 30, can be made of a material containing an embedded solid lubricant or of a solid lubricant material. It is also possible for the sealing lips 34 to be provided with a solid lubricant coating. To enhance this lubrication and / or to allow greater freedom in the material selection of the sealing lips 34, while simultaneously creating a friction-free contact situation, it is proposed to introduce additional lubricant into the sealing system. In the illustrated embodiment, lubricant is introduced into a chamber in the seal carrier 20. This chamber can be designed as a separate recess.

[0084] In the Figs. 1-3 In the illustrated embodiment, a recess, namely the sealing lip receiving recess 22, is already present on the sealing carrier 20. In the illustrated embodiment, this serves as a chamber and can be used to be filled with lubricant in order to reduce the friction of the sealing lips 34 on the counter-running surface 42.

[0085] To introduce lubricant into chambers 22-2 and 22-3, seal carriers 20-2 and 20-3 are therefore still provided, as in the Figures 2 and 3 As shown, radially arranged through-bores 26-2 and 26-3 are provided, which fluidically connect the chambers 22-2 and 22-3 to an external environment. To supply the chamber 22-4 with lubricant, the illustrated embodiment further provides, as shown in Figure 3 shown, an angled through-bore 46 is provided in the starting sleeve 40, which serves to introduce lubricant into the chamber 24-4.

[0086] The lubricant can serve two purposes: firstly, to equalize the water pressure acting on the sealing lips 34 and simultaneously ensure sufficient lubrication between the counter-running surface 42 and the sealing lip 34; and secondly, to completely fill the sealing system 100, so that all cavities are filled with lubricant. This ensures that the lubricant exerts the same pressure on both sides of the sealing lips 34 and simultaneously prevents water from penetrating the sealing system 100, as all cavities are filled with lubricant. To penetrate such a sealing system 100, the water would not only have to overcome the sealing lips 34 but also displace the lubricant from the sealing system 100.

[0087] It is particularly preferred that the respective sealing carrier 20 or the starting sleeve 40 not only has a single through-hole 26 or 46, but two through-holes are provided, which are arranged offset by 180° on the sealing carrier 20 or the starting sleeve 40, so that lubricant can be distributed bubble-free and evenly in the sealing system 100.

[0088] In order to seal the through-holes 26, 46 fluid-tight against the water environment after the lubricant has been introduced, the through-holes 26, 46, as shown in Figure 4The figure shows a first thread 27-1, 47-1 and a second thread 27-2, 47-2, which have different sizes. The first thread 27-1, 47-1 has a smaller diameter than the second thread 27-2, 47-2. A setscrew 60, preferably tapered, can be screwed into the first thread 27-1, 47-1, which is located radially further inwards, creating a seal, while a screw-in sealing plug 62 is screwed into the outer thread 27-2, 47-2. This also creates redundancy, ensuring that even under the most adverse conditions, water cannot penetrate the sealing system 100.

[0089] The through-holes 26 and 46 can also be used to check the sealing system 100 for leaks. For this purpose, a vacuum can be applied to each of the through-holes 26 and 46 to verify that the sealing lips 34 are in proper contact. This allows for verification that the sealing system 100 has been correctly installed even after it has been installed and before the underwater turbine is launched. Alternatively, a test fluid can be used instead of a vacuum, which is introduced into the sealing system 100 at a specific pressure.

[0090] In addition to the leak test for the dynamic sealing elements 34, the static seal 54, 55 can also be subjected to a leak test. For this purpose, the sealing system 100, as shown in Figure 2The mounting sealing ring 20-4 and the thrust sleeve 40 each have bores 28 and 48, respectively, which are angled and, in the case of the mounting sealing ring 20-4, open at an end face 29 between the two static seals 54-1 and 54-2. In the case of the thrust sleeve 40, the through-bore 48 opens into an inner surface 49. A test fluid can also be introduced or a vacuum applied via the through-bores 28 and 48 to check the tightness of the static seals 54 and 55.

[0091] Furthermore, a lubricant can be introduced into the through-bore 48 formed in the thrust sleeve 40, which distributes itself on the contact surface between the thrust sleeve 40 and the shaft 2, thus allowing axial displacement of the thrust sleeve 40. This is particularly advantageous when the thrust sleeve 40 is to be removed from the shaft 2 or when its axial position is to be shifted to prevent groove formation due to the contact pressure between the sealing lips 34 and the counter-running surface 42.

[0092] Furthermore, the Figs. 1-3 that on adjacent sealing carriers 20, an annular, axially projecting cantilever 64 is provided, which is received in a complementary annular groove 66. These serve for the self-centering of the sealing carriers 20.

[0093] Overall, by providing lubricant in the sealing system 100, wear in the sealing system can be significantly reduced and at the same time an improved seal against seawater can be achieved. Reference symbol list

[0094] 2 Rotor blade shaft 4 Rotor blades 6 Rotor hub 8 Bearing units 20 Seal carrier 21 Seal body receptacles 22 Seal lip receptacle; Chamber 23 Mounting hole 24 Thread 25 Annular groove in seal carrier 26 Through hole 27 Thread in through hole 28 Through hole 29 End face 30 Sealing element 32 Sealing body 34 Sealing lip 36 Running surface 37, 38 Support element 40 Throttle sleeve 42 Counter-running surface 44 Grooves 46 Through hole in throttle sleeve 47 Thread in through hole 48 Through hole 49 Inner surface 50 Fastening element 52 Ejector screw 54 Static seal 55 Static seal 56 Sacrificial anode 58 Spacer element 60 Grub screw 62 Plug 64 Annular projection 66 Annular indentation 100 Sealing system

Claims

1. Seal system (100) for sealing a rotatable component of an underwater turbine, in particular a shaft (2) of an underwater turbine, in particular an underwater turbine of a tidal power plant, with respect to water, in particular seawater, wherein the seal system (100) has a plurality of seal carriers (20) which are arranged adjacently with respect to each other, wherein each seal carrier (20) carries a sealing element (30) with a ringshaped seal body (32) and at least one sealing lip (34) extending from the seal body (32), wherein the seal body (32) is fastened to the seal carrier (20) and the sealing lip (34) extends in the direction of the rotating component and has a running surface (36), by way of which the sealing lip (34) runs on a counter-running surface (42) formed directly or indirectly on the rotatable component, wherein a clearance is provided between the seal carrier (20) and the rotatable component, which clearance forms a chamber (22), in which a lubricant is received, characterized in that the seal system (100) has a seal carrier (20) designed as a fastening seal carrier (20), wherein the fastening seal carrier (20) is designed to be fastened to a stationary component of the tidal plant, in particular to a bearing ring of a bearing unit (8) mounting a shaft (2) to be sealed or to a housing receiving a bearing unit (8), wherein, furthermore, the fastening seal carrier (20) has, on an end side (29) facing the stationary component, at least one annular groove (25) which is designed to receive a static seal (54), in particular an O-ring seal, wherein, furthermore, a bore (28) which has a first radially extending bore part and a second axially extending bore part is provided in the fastening seal carrier (20), wherein the axially extending bore part extends from the first bore part as far as the end side (29) facing the stationary component, with the result that the second bore part opens radially within the annular groove (25) into the end side (29); and / or in that the seal system (100) has, furthermore, a run-on sleeve (40) which forms a counter-running surface (42) for the plurality of sealing lips (34), wherein the run-on sleeve (40) has at least one annular groove (44) on its inner shell surface (49), which annular groove is designed to accommodate a static seal (55), in particular an O-ring seal, wherein, furthermore, a bore (46) is provided in the run-on sleeve (40), which bore has a first axially extending bore part and a second radially extending bore part, wherein the radially extending bore part extends from the first bore part as far as the inner shell surface (49), with the result that the second bore part opens into the inner shell surface (49) behind the annular groove (44) in the axial seal direction.

2. Seal system (100) according to Claim 1, wherein the seal carrier (20) has at least one through bore (26, 28) which is fluidically connected to the chamber (22).

3. Seal system (100) according to either of the preceding claims, wherein the radial bore (26) has a first radial outer thread (27-1) and a second radial inner thread (27-2), wherein the first thread (27-1) has a greater diameter than the second thread (27-2).

4. Seal system (100) according to any one of the preceding claims, wherein a recess which is open in the direction of the rotatable component and is formed as a sealing-lip-receiving recess (22) for receiving a sealing lip (34) is formed on the seal carrier (20), and wherein the recess (22) is dimensioned in such a way that a clearance which forms the chamber remains between the side, facing away from the running surface (36), of the sealing lip (34), received in the sealing-lip-receiving recess (22), and the seal carrier (20).

5. Seal system (100) according to any one of the preceding claims, wherein at least one seal carrier (20) has, preferably radially on the inside, an annular axially protruding projection (64) which is designed to engage with a complementarily configured annular axial notch (66) of an adjacently arranged seal carrier (20).

6. Seal system (100) according to any one of the preceding claims, wherein the at least one seal carrier (20) has, on its radially outer edge region, a plurality of circumferentially distributed fastening bores (23) which are preferably provided with a thread (24) and are designed to receive a fastening means (50) for fastening the seal carrier (20) and / or a forcing screw (52) for removing the seal carrier (20).

7. Seal system (100) according to Claim 6, wherein a plurality of seal carriers (20) are provided, which have, at their radially outer edge regions, a plurality of circumferentially distributed fastening bores (23), wherein the seal carriers (20) have different outer diameters, and wherein the outer diameters are dimensioned in such a way that the fastening bores (23) arranged in the radially outer edge region are freely accessible in the installed state of the seal system (100).

8. Seal system (100) according to any one of the preceding claims, wherein, furthermore, the seal carrier (20) has, on at least one end side (29), at least one annular groove (25) which is designed to receive a static seal (54), in particular an O-ring seal.

9. Seal system (100) according to any one of the preceding claims, wherein, furthermore, the seal system (100) has a seal carrier (20) formed as a cover seal carrier (20), wherein the cover seal carrier (20) is designed to cover the seal system (100) relative to an external environment, wherein the cover seal carrier (20) preferably has a seal body receiving groove (21-1), in which a particle seal (30-1) is arranged.

10. Seal system (100) according to Claim 9, wherein at least one first seal carrier (20) and a second further seal carrier (20) are provided between the fastening seal carrier (20) and the cover seal carrier (20), wherein the first seal carrier (20) is arranged adjacently with respect to the fastening seal carrier (20) and the second seal carrier (20) is arranged adjacently with respect to the cover seal carrier (20).

11. Seal system (100) according to Claim 10, wherein the fastening seal carrier (20) has an outer diameter which is greater than the outer diameter of the other seal carriers (20), and wherein the first seal carrier (20) has an outer diameter which is greater than the outer diameter of the second seal carrier (20), and wherein the cover seal carrier (20) has an outer diameter which is smaller than the outer diameters of the first and / or second seal carrier (20).

12. Seal system (100) according to any one of the preceding claims, wherein the bore (46) in the run-on sleeve (40) has a first axially outer thread (47-1) and a second axially inner thread (47-2), wherein the first thread (47-1) has a greater diameter than the second thread (47-2).

13. Seal system (100) according to Claim 12, wherein the run-on sleeve (40) is pressed onto the rotatable component (2).