SEALING SYSTEM FOR UNDERWATER TURBINE

Abstract

A sealing system (100) for sealing a rotatable component of an underwater turbine, in particular a shaft (2) of an underwater turbine, especially an underwater turbine of a tidal energy plant, against water, in particular seawater, is disclosed, wherein the sealing system (100) has several sealing carriers (20) arranged adjacent to one another, wherein each sealing carrier (20) carries a sealing element (30) with an annular sealing body (32) and at least one sealing lip (34) extending from the sealing body (32), wherein the sealing body (32) is attached to the sealing carrier (20) and the sealing lip (34) extends in the direction of the rotatable component and has a running surface (36) with which the sealing lip (34) contacts a counter-running surface (42) formed directly or indirectly on the rotatable component, wherein a free space is provided between the sealing carrier (20) and the rotatable component.forming a chamber (22) in which a lubricant is contained.

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, especially in marine applications such as tidal energy plants, are typically sealed from the surrounding water, especially seawater, using sealing systems. In particular, the bearing assemblies that movably 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 debris, particles, water, and marine species such as plankton and algae from penetrating the bearing assemblies and damaging their components. Particles can also penetrate the seals themselves, reducing seal life.

[0003] Typically, several adjacent seals are provided to create a redundant sealing system, whereby the lips of the adjacent seals can also be oriented in different directions.

[0004] However, the pressures prevailing in the water exert high forces on seals and the sliding surfaces in contact with them, causing mutual wear on these components within a short period of time, thus impairing their sealing effectiveness. Replacement can be complex and costly, and may not be possible at all times.

[0005] In particular, the seals may not be replaceable underwater. Therefore, such maintenance operations can be expensive and require frequent and extended shutdown of the underwater turbine.

[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.

[0007] This object is achieved by a sealing system according to patent claim 1.

[0008] The following proposes a sealing system for an underwater application, in particular a marine application. The sealing system is designed in particular for sealing a rotatable component, such as a shaft of an underwater turbine, in particular an underwater turbine of a tidal turbine, wherein the sealing system has a plurality of annular seal carriers arranged adjacent to one another. Each seal carrier carries at least one sealing element with an annular sealing body and at least one sealing lip extending from the sealing body, wherein the sealing body is fastened to the seal carrier and the sealing lip extends in the direction of the shaft to be sealed. The sealing element itself is preferably a seawater seal, i.e. a sealing element that is suitable for sealing against seawater.Furthermore, the sealing lip has a running surface with which the sealing lip engages a counter-running surface formed directly or indirectly on the rotating component. The counter-running surface can be formed directly by the rotating component itself, for example, the shaft, or indirectly by a stop element, such as a stop sleeve, that is non-rotatably attached to the rotating component.

[0009] In order to minimize wear on the sealing system and also wear on the mating surface, a free space is provided between the seal carrier and the rotating component, forming a chamber in which a lubricant is accommodated. For this purpose, the seal carrier can, for example, have a recess open towards the shaft, which forms the chamber. The lubricant accommodated in the chamber ensures that the friction between the sealing lip and the mating surface is reduced, which in turn reduces wear. In addition, the lubricant serves as corrosion protection for the internal seal carrier rings. The lubricant is preferably a lubricating grease. According to a further preferred exemplary embodiment, at least the sealing lip, preferably the entire sealing element, is made of a material that has 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 for a friction-reducing material to be applied to the sealing lip, particularly to the running surface, for example, by means of a suitable coating. This makes it possible to provide a friction-reduced sealing system that provides a friction-reduced seal even without the presence of lubricant, for example, after the lubricant has been used up or aged.

[0010] In a further preferred embodiment, a recess is formed on the seal carrier which is open in the direction of the rotatable component and forms the chamber. The recess forming the chamber is dimensioned and arranged such that a free space remains between a side of the sealing lip facing away from the running surface and the seal carrier, which free space forms the chamber to which lubricant can be applied. It is particularly preferred that the recess is designed as a sealing lip receiving recess which surrounds and receives a sealing lip, the free space between the sealing lip and the recess forming the chamber. This configuration enables the lubricant to reinforce the sealing effect of the sealing lip because it increases the contact pressure of the sealing lip on the counter-running surface.Likewise, this design ensures that the water pressure is balanced by the lubricant pressure on the first sealing lip that seals against water, which in turn reduces wear.

[0011] To further reduce wear in this design, it can also be provided that lubricant is also applied on the same side of the running surface of the sealing lip, so that the sealing lip is not subjected to additional pressure with respect to the lubricant. In this preferred embodiment, the introduced lubricant provides an additional barrier against the ingress of seawater, since the water must also displace the lubricant to penetrate into and through the sealing system.

[0012] 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. Furthermore, the bore can be used to remove any water that has penetrated the sealing system. Furthermore, the bore can be used to test the sealing ability 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 to test for leaks using negative or positive pressure, for example.

[0013] It is also advantageous if a sensor is arranged in the through-hole or in the chamber, which detects the entry of water into the chamber or into the hole and can preferably transmit this to a monitoring system.

[0014] It is further preferred if the seal carrier has two radial through-bores that are fluidically connected to the chamber, wherein the two radial bores are arranged offset from one another, preferably by 180°. Since the sealing system is usually designed to seal completely, 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 also the through-bores are filled with lubricant. The preferred 180° arrangement also ensures that the lubricant can spread evenly and bubble-free in the chamber and in the bores.

[0015] According to a further preferred embodiment, the radial bore has a first radially outer thread and a second radially inner thread, wherein the first thread has a larger diameter than the second thread. Such a configuration allows a redundant closure option for the bore, thus ensuring that no water can penetrate through the bore into the sealing system. It is particularly preferred that the second thread is designed to accommodate a, preferably conical, grub screw, which is sealingly received in the thread, while the first thread is closed with a sealingly screwable plug.

[0016] According to a further preferred embodiment, each seal carrier further comprises at least one seal body receiving recess designed to receive the seal body of the sealing element in a rotationally fixed manner. This recess is preferably open toward an end face of the annular seal carrier and has an axial depth that is less than the overall height of the seal body. When an elastomeric seal body is provided, the elastomeric deformation during installation of the sealing system can press the contact surfaces of the seal body sealingly against the contact surfaces in the recess of the seal carrier and on an adjacent element. This additionally allows a static seal to be achieved between the seal carriers.

[0017] Alternatively or additionally, the seal carrier may further comprise at least one annular groove on at least one end face, which is designed to receive a static seal, in particular an O-ring seal.

[0018] Preferably, the sealing body receiving recess and the sealing lip receiving recess are arranged axially spaced from one another at two axial ends of the seal carrier. This enables a preferred embodiment in which the sealing lip receiving recess is designed to receive the sealing lip of a sealing element carried by an adjacently arranged seal carrier.

[0019] It is further preferred if the recess is designed in such a way that a supporting effect for the sealing lip and a radial support for the sealing body are provided. The supporting effect for the sealing lip ensures that the sealing lip cannot "fold over" due to the pressure acting on it. The support for the sealing body enables radial support or retention of the sealing body directed toward the rotating component. For this purpose, corresponding support elements can be formed on the seal carrier.

[0020] According to a further preferred embodiment, at least one seal carrier has, preferably radially inwardly, an annular axially projecting projection designed to engage with a complementary annular axial notch of an adjacently arranged seal carrier. This allows self-centering of the individual seal carriers. Furthermore, the engagement of the projection in the notch represents a further obstacle to water penetration.

[0021] 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.

[0022] According to a further preferred embodiment, the at least one seal carrier has a plurality of circumferentially distributed, preferably threaded, mounting holes on its radially outer edge region, which are designed to accommodate a fastener for securing the seal carrier and / or a forcing screw for disassembling the seal carrier. Due to the high screwing pressure required to ensure that the seal carrier and its mounting counterpart adhere to each other as tightly as possible, as well as due to contamination and possible corrosion, the two parts can "stick" together after prolonged use. They often cannot be separated from each other without damage, for example, to service a sealed bearing or to replace the entire sealing system.The possibility of screwing a forcing screw into the seal carrier allows the seal carrier to be pressed off the counterpart and thus easily removed.

[0023] If multiple seal carriers are provided, each of which has a plurality of circumferentially distributed mounting holes on its radially outer edge region, it is further preferred that the seal carriers have different outer diameters, wherein the outer diameters are dimensioned such that the mounting holes arranged in the radially outer edge region 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 allows the sealing system to be serviced even underwater.

[0024] Furthermore, an embodiment is advantageous in which the sealing system has a seal carrier designed as a fastening seal carrier, wherein the fastening seal carrier is designed to be fastened to a stationary component of the tidal turbine, 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 fastening 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 past the sealing system into the underwater turbine.

[0025] Preferably, a second annular groove is also provided radially within the first groove, which is also designed to accommodate a static seal, in particular an O-ring seal. This creates redundancy at this sealing location, reliably preventing water from penetrating the underwater turbine.

[0026] According to a further preferred embodiment, a bore is provided in the fastening seal carrier, which bore 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, such that the second bore part opens into the end face radially inside the first, and preferably radially outside the second annular groove. This bore, like the bores mentioned above that fluidically connect the chamber, can be used to test the sealing ability of the static seal. For this purpose, a test fluid can also be introduced into this bore, which is, for example, pressurized with a predetermined pressure up to which the static seal is intended to at least seal.

[0027] According to a further preferred embodiment, the fastening seal carrier has a plurality of circumferentially distributed, preferably threaded, fastening bores on its radially outer edge region, which are designed to accommodate a fastener for fastening the fastening seal carrier to the stationary component and / or a forcing screw for disassembling the fastening seal carrier from the stationary component. Due to the high screwing pressure required to ensure that the fastening seal carrier and the stationary component fit together as tightly as possible, as well as due to contamination and possible corrosion, the two parts can "stick" together after prolonged use. They often cannot be separated from each other without damage, for example, to service a sealed bearing or to replace the entire sealing system.The possibility of screwing a forcing screw into the fastening seal carrier allows the seal carrier to be pressed off the stationary component and thus be easily dismantled.

[0028] Furthermore, it is preferred that the fastening 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 fastening bores 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 the stationary component as a complete unit and removed again without having to disassemble the sealing system into its individual parts. This also allows the sealing system to be tested for its sealing capability before installation.

[0029] On the side facing away from the fastening seal carrier and thus on the side facing away from the stationary component, i.e., toward the surrounding water, the sealing system preferably further comprises a seal carrier designed as a cover seal carrier, wherein the cover seal carrier is designed to cover the sealing system from the external environment. Instead of a seawater seal, this cover seal carrier may comprise only a particle seal, which is designed to prevent external elements, such as dust, abrasion, particles, and marine species, such as plankton and algae, from penetrating the sealing system.

[0030] Analogous to the fastening seal carrier, the cover seal carrier can preferably also have a plurality of circumferentially distributed, preferably threaded, fastening bores on its radially outer edge region, which are designed to receive a fastening means for fastening the fastening seal carrier to an adjacent or another seal carrier and / or a forcing screw for dismantling the cover seal carrier from the adjacent seal carrier.

[0031] 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 does not restrict accessibility to the other seal carriers when installed.

[0032] According to a further preferred embodiment, at least one first seal carrier and a second additional seal carrier are provided between the fastening seal carrier and the cover seal carrier, wherein the first seal carrier is arranged adjacent to the fastening seal carrier and the second seal carrier is arranged adjacent to the cover seal carrier. This creates sufficient redundancy so that even if one sealing element fails, additional sealing elements are present to prevent water from penetrating the underwater turbine. The number of additional seal carriers can depend on the area of ​​application. For example, the number of sealing lips depends on the expected water pressure and / or service life.

[0033] Analogous to the fastening seal carrier and the cover seal carrier, it is advantageously also provided that the first seal carrier, preferably on its radially outer edge region, has a plurality of circumferentially distributed, preferably threaded, fastening bores which are designed to receive a fastening means for fastening the first seal carrier to the fastening seal carrier and / or a forcing screw for dismantling the first seal carrier from the fastening seal carrier and / or the second seal carrier, preferably on its radially outer edge region, has a plurality of circumferentially distributed, preferably threaded, fastening bores which are designed to receive a fastening means for fastening the second seal carrier to the first seal carrier and / or a forcing screw for dismantling the second seal carrier from the first seal carrier.

[0034] Alternatively, the second seal carrier may not have its own screw connection, but rather the fastening openings are designed to accommodate the fastening means of the cover seal carrier, so that the second seal carrier and the cover seal carrier are screwed together to the fastening seal carrier. The option of screwing in a forcing screw can also be provided separately for the second seal carrier in this embodiment.

[0035] As mentioned above, this allows the sealing system to be attached to the stationary component as a unit, but also allows 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.

[0036] According to a further preferred embodiment, at least the first seal carrier has an outer diameter that is larger than the outer diameter of the second seal carrier, wherein the outer diameters are preferably dimensioned such that the fastening bores arranged in the radially outer edge region are freely accessible when the sealing system is installed. This also allows the accessibility and replaceability of individual components of the sealing system to be achieved without having to remove the entire sealing system from the stationary component. This allows the sealing system to be serviced even underwater.

[0037] If the second seal carrier and the cover seal carrier are designed to be mounted together, it is advantageous that their outer diameters are the same.

[0038] As mentioned above, the sealing lips of the sealing system engage a counter-running surface. This counter-running surface can be formed by the rotating component itself. However, since the engagement of the sealing lips can cause wear, particularly the formation of grooves on the counter-running surface, it is preferable, especially when sealing shafts, to use a thrust sleeve that is non-rotatably attached to the rotating element, particularly the shaft.

[0039] In this case, an advantageous design is one in which the thrust sleeve is pressed onto the shaft. The advantage of the press fit is that the thrust sleeve can be designed to be significantly more space-saving, as a flange for securing the sleeve is eliminated. Furthermore, it can result in lower costs, as a material- and labor-intensive design with a flange and screws is eliminated.

[0040] In order to also seal the underwater turbine against water ingress along the thrust sleeve, the thrust sleeve can preferably have at least one annular groove on its inner surface, which is designed to accommodate a static seal, in particular an O-ring seal. Preferably, a second annular groove is provided here as well, which is axially offset in the direction of the stationary component compared to the first groove and is also designed to accommodate a static seal, in particular an O-ring seal. This allows redundancy to be created at this point to be sealed, which reliably prevents water from penetrating the underwater turbine.

[0041] The thrust sleeve can be designed to be axially movable, so that the sealing lips engage at an axially offset location 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.

[0042] In order to facilitate the axial displaceability of the pressed-on thrust sleeve, a bore is also provided in the thrust sleeve, 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 to the inner circumferential surface, so that the second bore part, in the installed state, opens into the inner circumferential surface between the stationary component and the annular groove, preferably between the first and second annular groove. The opening is preferably arranged centrally in the thrust sleeve. A lubricant, in particular an oil, can be introduced into this bore for the axial displaceability, which lubricant deposits on the contact surface between the thrust sleeve and the rotatable component and facilitates the axial displaceability.

[0043] At the same time, this bore can also be used to test the sealing capability of the static seal. For this purpose, as described above, a test fluid can be introduced, which is, for example, subjected to a predetermined pressure, up to which the static seal must be sealed.

[0044] According to a further preferred embodiment, the thrust sleeve has at least one second bore, which 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 to the outer circumferential surface. This second bore is fluidly connected to one of the lubricant-receiving chambers of the sealing system. Through this through-bore, lubricant can also be introduced into the chamber via the thrust sleeve. In addition, the bore can be used to remove any water that has penetrated from the sealing system. Furthermore, the bore in the thrust sleeve can also be used to test the sealing ability of the sealing lip after installation of the sealing system in the underwater turbine. For this purpose, for example, a vacuum can be applied to the through-bore or a test fluid can be introduced.

[0045] It is also advantageous if a sensor is arranged in the through-hole or in the chamber, which detects the entry of water into the chamber or into the hole and can preferably transmit this to a monitoring system.

[0046] Analogous to the seal carrier, it is also preferred for the thrust sleeve if the thrust sleeve has two second through-bores that are fluidically connected to the chamber, wherein the two second bores are arranged offset from one another, preferably by 180°. Since the sealing system is usually designed to seal completely, 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 bubble-free in the chamber and in the bores.

[0047] Furthermore, an embodiment is advantageous in which all chambers of the sealing system are connected via bores in the thrust sleeve for introducing a lubricant or a test fluid or for applying a vacuum, in which case no bores are provided in the seal carriers. In this embodiment, too, an inlet and an outlet can be provided—i.e., a further central axial bore with corresponding branches, preferably offset by 180°.

[0048] According to a further preferred embodiment, the at least one bore in the thrust sleeve has a first axially outer thread and a second axially inner thread, wherein the first thread has a larger diameter than the second thread. Such a configuration allows a redundant closure option for the bore, so that it can be ensured that no water can penetrate through the bore into the sealing system. It is particularly preferred that the second thread is designed to accommodate a preferably conical grub screw, which can be screwed sealingly into the internal second thread, while the first thread is closed with a sealing screw-in plug.

[0049] According to a further preferred embodiment, a sacrificial anode is further attached to the sealing system, in particular to the cover seal carrier, which protects the sealing system from corrosion.

[0050] It is particularly preferred if the sacrificial anode is attached to the optionally attached thrust sleeve and / or to the cover seal carrier. The sacrificial anode can also be attached to the thrust sleeve via a spacer element, wherein the spacer element reduces the distance to another component arranged on the shaft, such as a rotor or rotor blade, and thus ensures that the axial displacement of the thrust sleeve is axially limited. With the pressed-on thrust sleeve, it can be ensured that the thrust sleeve does not shift on the shaft due to aging, such as material- and age-related expansion.

[0051] The sealing system can be used at various locations on the underwater turbine. It is particularly suitable 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.

[0052] The bearing units that support the rotating components, especially the shaft, and which can be sealed using the sealing system, can be roller bearings or plain bearings. They can also form a slewing ring for the rotation of the rotor blade or nacelle.

[0053] According to a preferred embodiment, the sealing system is used on the pivot system for the rotor blades attached to a rotor hub. It is particularly advantageous if the bearing arrangement is not designed as a pivot bearing with a massive and large-dimensioned outer bearing ring, but rather as a bearing arrangement with two spaced-apart bearing units. The rotor hub serves as the bearing housing, and the sealing system is attached directly to the rotor hub and not, as in the prior art, to the outer bearing ring of the pivot bearing. Although the rotor hub itself is not a stationary component, the rotor hub is stationary with respect to the rotation of the rotor blade. The shaft bearing can be designed, for example, as a combination of a loose and a fixed bearing, or a combination of two adjusted tapered roller bearings.

[0054] A further 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.

[0055] Yet another aspect of the invention relates to an underwater turbine having a sealing system as described above.

[0056] Further advantages and advantageous embodiments are set forth in the description, the drawings, and the claims. In particular, the combinations of features set forth in the description and the drawings are purely exemplary, so the features may also be present individually or in other combinations.

[0057] The invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the appended claims.

[0058] 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 from Fig. 1 ; Fig. 3: a third sectional view through the preferred embodiment of the sealing system from Fig. 1 ; and Fig. 4: a fourth sectional view through the preferred embodiment of the sealing system from Fig. 1 .

[0059] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0060] The Figures 1 to 4 show various sectional views through different sectional planes of a preferred embodiment of a sealing system 100 for sealing a rotatable component of an underwater turbine. In the illustrated figures, the sealing system 100 is designed for sealing a bearing of a rotatable rotor blade. However, the sealing system 100 can be used for any seal, such as a rotor shaft main bearing or a bearing for a rotating nacelle.

[0061] In the exemplary embodiment illustrated 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 non-rotatably mounted. The rotor blade shaft 2, in turn, is rotatably mounted in a rotor hub 6, with bearing assemblies 8 being provided for the support. Rolling bearings or plain bearings can be used as bearing units. The bearing units 8, schematically illustrated here as rolling bearings, are to be viewed purely schematically as placeholders for any desired bearing type.

[0062] The sealing system 100, in turn, comprises a plurality of annular seal carriers 20-1, 20-2, 20-3, 20-4. Each seal carrier 20 is designed to support at least one dynamic sealing element 30, wherein the sealing elements 30 are arranged in associated seal body receiving recesses 21 formed on the respective seal carriers 20.

[0063] As can be seen from the detailed view of Fig. 1a, the dynamic sealing elements 30 each have 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 inward towards the shaft 2. Furthermore, the sealing elements 30 have a running surface 36 with which the sealing elements run against a counter-running surface 42. In this illustrated embodiment, the counter-running surface 42 is formed by a run-up sleeve 40, but it could also be the case that the sealing lips 34 rest directly on the shaft 2.

[0064] Furthermore, Fig. 1a shows that the seal carrier 20 has a first support element 37 and a second support element 38, which are designed to support and carry the sealing lip and the sealing body 32, respectively. The support element 37 is designed to support the sealing lip 34 and, even under high water pressure on the sealing lip, to ensure that the sealing lip 34 does not "fold over," i.e., bend toward the side to be sealed. The support element 38 serves to support the sealing body 32 radially inward and thus, together with the adjacent seal carrier, to create a narrow receiving space for the sealing body 32, so that the sealing body 32 is accommodated in the sealing system in a rotationally fixed and statically sealing manner.

[0065] In order to form a sealing system that is as compact as possible, sealing lip receiving recesses 22 are further formed on the seal carriers, which can receive a sealing lip of a sealing element carried by the seal carrier itself (see seal carriers 20-3 and 20-4) or a sealing lip of a sealing element carried by an adjacent seal carrier (see seal carriers 20-1 and 20-2).

[0066] As can also be seen from the exemplary embodiment, various dynamic sealing elements 30 are provided in the sealing system, which fulfill different sealing tasks. Thus, the sealing element 30-1 is designed as a particle seal, which in the sealing system 100 ensures that contaminants are prevented from entering the sealing system 100. The seals 30-2 to 30-4, on the other hand, are designed as so-called seawater seals and have sealing lip geometries and materials that ensure that water is prevented from entering the rotor hub 6. For this purpose, the sealing lips 34 of the seawater seals are directed in particular in the direction of the rotor blade 4.

[0067] 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 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 toward the bearing unit 8. The seal body receiving recess 21 can be designed as a groove 21-1, as shown in the seal carrier 20-1, but it can also be designed as a recess open toward the end face, as shown in the seal carriers 20-2 to 20-4.

[0068] In the illustrated embodiment, the seal carrier 20-1 is designed as a cover seal carrier, while the seal carrier 20-4 is designed as a fastening seal carrier, which in the illustrated embodiment is attached directly to the rotor hub 6. Depending on the design of the bearing unit 8, the fastening seal carrier can also be attached directly to a bearing ring.

[0069] As mentioned above, the seal carriers 20 have recesses 22 designed to accommodate 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 accommodated in the recess 22-1, and the sealing lip 34-3 of the sealing element 30-3 carried by the third seal carrier 20-3 is accommodated in the recess 22-2.

[0070] The recesses 22-3 and 22-4, respectively, are designed to accommodate sealing lips of a sealing element carried by the same seal carrier. Thus, the seal 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 seal carrier 20-4.

[0071] In the Figures 1-3 In the embodiment shown, it can also be seen that fastening holes 23 are provided on the seal carriers 20 in a radially outer edge region. The fastening holes are designed in such a way that they are designed either for receiving a fastening means, in particular a screw 50 (see Fig. 1 and Fig. 3 ) or a so-called forcing screw 52 (see Fig. 2). For this purpose, a thread 24 can be provided in the opening, but it is also possible for the opening to be a smooth bore. Preferably, no thread is provided in the fastening bores 23 intended to receive a screw 50, but only in the fastening bores 23 intended to receive the forcing screw 52.

[0072] In the shown sectional view of the Figure 2 Only the cover seal carrier 20-1 and the fastening seal carrier are equipped with a forcing screw 52. However, this can also be provided on the seal carriers 20-2 and 20-3 arranged between them.

[0073] The forcing screws 52 serve to disassemble 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 disassembly of the seal carrier rings for maintenance purposes is often not possible. However, with the help of the forcing screws 52, the seal carrier 20 can be detached from the respective fastening partner without causing damage. The forcing screw 52 is screwed into the thread 24, whereby the forcing screw 52 itself has a longer axial length than the seal carrier 20 itself, so that the forcing screw 52 abuts against the respective other fastening partner and, if further tightened, pushes the seal carrier 20 away from the respective fastening partner.

[0074] Furthermore, the figures show that the seal carrier 20-2 is screwed to the adjacent seal carrier 20-3 by means of the cover seal carrier 20-1. Of course, it would also be possible to screw the seal carrier 20-2 on independently. Furthermore, the exemplary embodiment shows that the mounting holes are provided in a radially outer edge region of the seal carrier 20.

[0075] It should also be noted that the seal carrier 20-2 and the seal carrier 20-3 can not only be screwed to the adjacent seal carrier 20-3 and 20-4, respectively, but can also be attached to another element via one or more seal carriers. However, the embodiment shown here has the advantage that the sealing system 100 can be screwed directly to the rotor hub 6 as a prefabricated unit.

[0076] Furthermore, the figures show that the fastening seal carrier 20-4 has the largest outer diameter, while the adjacent seal carriers 20-3, 20-2, and 20-1 have a smaller outer diameter. This allows the fastening bores 23, which are arranged in the radially outer region of the respective seal carriers 20, to be freely accessible even when installed. Similar to the fastening seal carrier 20-4, the adjacent seal carrier 20-3 also has an outer diameter slightly larger than the adjacent seal carrier 20-2.

[0077] In the illustrated embodiment, the seal carrier 20-2 and the cover seal carrier 20-1 have the same outer diameter and are jointly attached to the first seal carrier 20-3. Of course, it would also be possible to provide a gradation between the second seal carrier 20-2 and the cover seal carrier 20-1 and to also attach the seal carrier 20-2 separately to the seal carrier 20-3.

[0078] Furthermore, the Figures 1-3that static seals 54, 55 in the form of, for example, O-rings are arranged for sealing between the rotationally connected elements, namely between the fastening seal carrier 20-4 and the rotor hub 6, or between the thrust sleeve 40 and the shaft 2. For this purpose, the fastening seal carrier 20-4 has annular grooves 25 into which O-rings 54 can be inserted. Likewise, 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 seal carriers.

[0079] In order to further protect the sealing system 100 from corrosion, a sacrificial anode 56 is provided, which is arranged adjacent to the sealing system 100 and the thrust sleeve 40. Furthermore, Figure 1 that the sacrificial anode 56 is surrounded by a spacer element 58 (see Fig. 3) that is dimensioned to minimize the distance between the spacer element 58 and the rotor blade 4. This ensures that the thrust sleeve 40 has only limited axial play, which in turn prevents unwanted axial displacement and thus a deterioration of the sealing properties. This ensures the preferred redundancy, particularly with the thrust sleeve that is press-fitted.

[0080] In order to keep wear on the sealing lips 34 and the starting sleeve 40 as low as possible, a starting condition that is as friction-free as possible must be created between the sealing lip 34 and the counter-running surface 42. For this purpose, the sealing lips 34 or, in general, the sealing element 30 can be made of a material that contains an embedded solid lubricant or can be made of a solid lubricant material. It is also possible for the sealing lips 34 to be provided with a solid lubricant coating. To support this lubricity and / or to achieve greater freedom in the choice of material for the sealing lips 34, but at the same time to create a contact situation that is as friction-free as possible, it is proposed to additionally introduce lubricant into the sealing system. For this purpose, in the illustrated embodiment, lubricant is introduced into a chamber in the seal carrier 20. The chamber can be designed as an independent recess.

[0081] In the Fig. 1-3 In the illustrated embodiment, a recess, namely the sealing lip receiving recess 22, is already present on the seal carrier 20. In the illustrated embodiment, this serves as a chamber and can be used to fill with lubricant to reduce the friction of the sealing lips 34 on the counter-running surface 42.

[0082] In order to introduce lubricant into the chamber 22-2 and 22-3, therefore, the seal carriers 20-2 and 20-3 are still provided with lubricant, as shown 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 with an external environment. In order to supply the chamber 22-4 with lubricant, in the embodiment shown, as shown in Figure 3 shown, an angled through hole 46 is provided in the thrust sleeve 40, which serves to introduce lubricant into the chamber 24-4.

[0083] The lubricant can serve, on the one hand, to compensate for the water pressure acting on the sealing lips 34 and, at the same time, to ensure sufficient lubrication between the counter-running surface 42 and the sealing lip 34. On the other hand, the lubricant can completely fill the sealing system 100 so that all cavities are filled with lubricant. This ensures that the lubricant applies the same pressure to the sealing lips 34 on both sides and, at the same time, prevents water from penetrating the sealing system 100, since all cavities are filled with lubricant. In order to penetrate such a sealing system 100, the water would have to overcome the sealing lips 34 and also displace the lubricant from the sealing system 100.

[0084] It is particularly preferred that not only a single through-bore 26 or 46 is provided in the respective seal carrier 20 or the thrust sleeve 40, but two through-bores are provided in each case, which are arranged offset by 180° on the seal carrier 20 or the thrust sleeve 40, so that lubricant can be distributed bubble-free and evenly in the sealing system 100.

[0085] In order to seal the through holes 26, 46 fluid-tight against the water environment after the introduction of the lubricant, the through holes 26, 46 have, as shown in Figure 4As shown, the sealing system 27-1, 47-1 also has a first thread 27-1, 47-1 and a second thread 27-2, 47-2, which have different sizes. Thus, the first thread 27-1, 47-1 is smaller in diameter than the second thread 27-2, 47-2. A preferably conical grub screw 60 can be sealingly screwed into the first thread 27-1, 47-1, which is arranged radially further inward, while a screw-in sealing plug 62 is sealingly screwed into the outer thread 27-2, 47-2. This also creates redundancy, which ensures that water cannot penetrate the sealing system 100 even under the most adverse conditions.

[0086] The through-holes 26, 46 can also be used to test the sealing system 100 for leaks. For this purpose, a vacuum can be applied to each of the through-holes 26, 46 to check whether the sealing lips 34 are sealing. This allows for checking whether the sealing system 100 has been installed correctly, even after the installation of the sealing system 100 and before the underwater turbine is launched. Instead of a vacuum, a test fluid can of course also be used, which is introduced into the sealing system 100 at a specific pressure.

[0087] 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 2As shown, the fastening seal ring 20-4 and the thrust sleeve 40 have bores 28 and 48, respectively, which are angled and, in the case of the fastening seal carrier 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, however, the through-bore 48 opens into an inner circumferential surface 49. A test fluid can also be introduced via the through-bores 28 and 48, or a vacuum can be applied, in order to check the tightness of the static seals 54, 55.

[0088] Furthermore, a lubricant can be introduced into the through-bore 48 formed in the thrust sleeve 40, which is distributed over 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 it is to be displaced in its axial position to prevent groove formation due to the contact pressure between the sealing lips 34 and the counter-running surface 42.

[0089] Furthermore, the Fig. 1-3 that an annular, axially projecting projection 64 is provided on each adjacent seal carrier 20, which is received in a complementary annular notch 66. These serve to self-center the seal carrier 20.

[0090] Overall, by providing lubricant in the sealing system 100, wear in the sealing system can be significantly reduced and, at the same time, improved sealing against seawater can be achieved. List of reference symbols

[0091] 2Rotor blade shaft 4Rotor blades 6Rotor hub 8Bearing units 20Seal carrier 21Seal body recesses 22Seal lip recess; 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 Thrust sleeve 42 Counter running surface 44 Grooves 46 Through hole in thrust sleeve 47 Thread in through hole 48 Through hole 49 Inner surface 50 Fastener 52 Forcing screw 54 Static seal 55 Static seal 56 Sacrificial anode 58 Spacer element 60 Grub screw 62 Plug 64 Annular projection 66 Annular notch 100 Sealing system

Claims

1. A sealing 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 energy plant, against water, in particular seawater, wherein the sealing system (100) comprises a plurality of seal carriers (20) arranged adjacent to one another, each seal carrier (20) carrying a sealing element (30) with an annular sealing body (32) and at least one sealing lip (34) extending from the sealing body (32), the sealing body (32) being fastened to the seal carrier (20) and the sealing lip (34) extending in the direction of the rotatable component and having a running surface (36) with which the sealing lip (34) abuts against a counter-running surface (42) formed directly or indirectly on the rotatable component, characterized in thata free space is provided between the seal carrier (20) and the rotatable component, which forms a chamber (22) in which a lubricant is accommodated.

2. Sealing 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. Sealing system (100) according to one of the preceding claims, wherein the radial bore (26) has a first radially outer thread (27-1) and a second radially inner thread (27-2), the first thread (27-1) having a larger diameter than the second thread (27-2).

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

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

6. Sealing system (100) according to 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), preferably provided with a thread (24), which are designed to receive a fastening means (50) for fastening the seal carrier (20) and / or a forcing screw (52) for dismantling the seal carrier (20).

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

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

9. Sealing system (100) according to one of the preceding claims, wherein the sealing system (100) comprises 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 system, in particular to a bearing ring of a bearing unit (8) supporting the shaft (2) to be sealed or to a housing accommodating the bearing unit (8), wherein the fastening seal carrier (20) further comprises, on an end face (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 preferably a bore (28) is further provided in the fastening seal carrier (20), which bore 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 (29) facing the stationary component, so that the second bore part opens radially inside the annular groove (25) into the end face (29).

10. Sealing system (100) according to one of the preceding claims, wherein the sealing system (100) further comprises a seal carrier (20) designed as a cover seal carrier (20), wherein the cover seal carrier (20) is designed to cover the sealing system (100) from an external environment, wherein preferably the cover seal carrier (20) has a seal body receiving groove (21-1) in which a particle seal (30-1) is arranged.

11. Sealing system (100) according to claim 9 and 10, wherein at least a 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 adjacent to the fastening seal carrier (20) and the second seal carrier (20) is arranged adjacent to the cover seal carrier (20).

12. Sealing system (100) according to claim 11, wherein the fastening seal carrier (20) has an outer diameter that is larger than the outer diameters of the other seal carriers (20), and wherein the first seal carrier (20) has an outer diameter that is larger than the outer diameter of the second seal carrier (20), and wherein the cover seal carrier (20) has an outer diameter that is smaller than the outer diameters of the first and / or the second seal carrier (20).

13. Sealing system (100) according to one of the preceding claims, wherein the sealing system (100) further comprises a thrust sleeve (40) which forms a counter-running surface (42) for the plurality of sealing lips (34), wherein the thrust sleeve (40) preferably has on its inner circumferential surface (49) at least one annular groove (44) which is designed to receive a static seal (55), in particular an O-ring seal.

14. Sealing system (100) according to claim 13, wherein a bore (46) is further provided in the thrust 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 to that of the inner circumferential surface (49), so that the second bore part opens into the inner circumferential surface (49) behind the annular groove (44) in the axial sealing direction, wherein preferably the bore (46) has a first axially outer thread (47-1) and a second axially inner thread (47-2), wherein the first thread (47-1) has a larger diameter than the second thread (47-2).

15. Sealing system (100) according to claim 13 or 14, wherein the thrust sleeve (40) is pressed onto the rotatable component (2).