Bearing lubrication of a shaft turbine by means of natural pressure difference

Abstract

The invention relates to a turbine generator device (2) comprising an annular housing (6) with a bearing device (12), an annular generator (15), and a turbine impeller (10) coupled for conjoint rotation to a turbine shaft (14). The bearing device (12) comprises a first axial plain bearing (26), a second axial plain bearing (27) and a first radial plain bearing (28a), wherein a turbine shaft (14) oriented along the axis of rotation (11) of the turbine is mounted by means of the plain bearings (26, 27, 28). A filtering and conveying device (30) for the cooling and lubricating liquid to be fed to the plain bearings (26, 27, 28) is formed at a first axial end face (29) of the bearing device (12). The cooling and lubricating liquid can flow sequentially through a first bearing gap space (31) of the first axial plain bearing (26), thereafter through a second bearing gap space (32) of the second axial plain bearing (27) and thereafter through a third bearing gap space (33) of the first radial plain bearing (28a), wherein the cooling and lubricating liquid is able to flow into a collecting chamber (35) located or mounted downstream of the plain bearings (26, 27, 28) along the flow path (34) of the cooling and lubricating liquid.

Description

[0001] The invention relates to a turbine-generator device for generating electricity by converting the energy of a flow between an upstream and a downstream watercourse. The turbine-generator device comprises a bearing assembly with plain bearings and a filter and conveying device for the cooling and lubricating fluid supplied to the plain bearings. Related inventions are known from the prior art.

[0002] EP2250367B1, for example, discloses a tubular turbine generator unit comprising a turbine runner, a drive shaft rigidly connected to the turbine runner, an electric generator with a generator rotor and a generator stator, wherein the generator rotor is driven at least indirectly by the drive shaft, a tubular turbine casing enclosing the electric generator, a bearing arrangement located within the tubular turbine casing and serving to support the drive shaft, and a floodable space within the tubular turbine casing which is flooded with water during operation of the tubular turbine generator unit, wherein the generator gap between the generator rotor and the generator stator and the bearing gap of the bearing arrangement are part of the floodable space.

[0003] Furthermore, DE102009021289A1 shows a bearing arrangement comprising a bearing through which a medium, in particular water, flows, a shaft which is received in the bearing, a filter device which is connected upstream of the bearing on the inflow side and which removes the particles from the medium, wherein the filter device comprises a protective cap and a fine filter, wherein the protective cap is connected upstream of the fine filter on the inflow side, and a conveying device for the medium which is arranged between the protective cap and the fine filter.

[0004] The designs of bearing arrangements known from the prior art describe only partially satisfactory solutions, particularly for use in turbine-generator units with a ring generator in a shaft power plant.

[0005] The object of the present invention was to overcome the disadvantages of the prior art and to provide a turbine-generator device with a bearing device by means of which bearing device, on the one hand, ensures a particularly uniform flow through the sliding bearings and, on the other hand, reduces the design effort and the necessary auxiliary components and means of the turbine-generator device.

[0006] This task is solved by a device according to the claims.

[0007] The turbine-generator device according to the invention for generating electricity by converting the energy of a flow between an upstream water level and a downstream water level in a shaft power plant with an intake basin comprises an annular casing with an inlet area and an outlet area, a ring generator, and a turbine runner with a turbine axis of rotation. The annular casing includes, in the inlet area, a pear-shaped bearing device aligned along the turbine axis of rotation, wherein the bearing device is fixedly held in position on the annular casing by means of at least one connecting element.The bearing arrangement comprises a first hydrodynamic axial plain bearing, a second hydrodynamic axial plain bearing spaced apart from the first axial plain bearing in the direction of the turbine's axis of rotation, and a first hydrodynamic radial plain bearing. A turbine shaft aligned along the turbine's axis of rotation is supported by the plain bearings, and the turbine impeller is rotationally fixed to the turbine shaft in the outlet region. At a first axial end face of the bearing arrangement, or in the inlet region, the bearing arrangement includes a filter and conveying device for the cooling and lubricating fluid supplied to the plain bearings.

[0008] A first bearing gap of the first axial plain bearing, followed by a second bearing gap of the second axial plain bearing and followed by a third bearing gap of the first radial plain bearing are sequentially, serially or in series through which the cooling and lubricating fluid can flow, wherein the cooling and lubricating fluid can flow into a collection chamber that follows or is downstream of the plain bearings along the flow path of the cooling and lubricating fluid.

[0009] The turbine shaft has at least a section of at least one flow channel oriented substantially parallel to the turbine's axis of rotation. In the outlet region of the turbine-generator unit, or in the region where the turbine shaft is coupled to the turbine runner, this flow channel can be fluidically coupled to the operating medium flowing through the turbine-generator unit. This allows the cooling and lubricating fluid, viewed in the direction of flow through the turbine-generator unit, to be discharged downstream of the turbine runner into the power plant's outlet. For this purpose, the turbine shaft has a connecting channel that can be fluidically coupled to the flow channel and the collection chamber, enabling the cooling and lubricating fluid to flow through the bearing assembly.

[0010] This allows the bearing assembly, or rather all the plain bearings of the bearing assembly, to be permeated by cooling and lubricating fluid. The cooling and lubricating fluid is guided through the bearing gaps of the plain bearings by the naturally occurring pressure difference between the inlet and outlet areas, which is also caused by the design of the shaft power plant and the turbine-generator unit. An advantage of this is that, by utilizing the natural pressure difference between the inlet and outlet areas, or between before and after the turbine-generator unit, a simple design of the bearing assembly is possible, thus avoiding the need for additional auxiliary equipment to supply the cooling and lubricating fluid.The simplified design, in addition to the obvious economic advantages in the manufacture and operation of the turbine-generator unit, also improves the service life and stability of the turbine-generator unit.

[0011] Furthermore, it can be advantageous for the flow channel to be designed along the turbine axis of rotation and rotationally symmetrical to the turbine axis. It can also be advantageous to provide several connecting channels distributed around the circumference of the turbine shaft. This allows the turbine shaft to be designed, at least in sections, as a hollow shaft in order to discharge the cooling and lubricating fluid centrally from the collection chamber. This ensures a pressure distribution of the cooling and lubricating fluid that is as homogeneous as possible in the circumferential direction within the bearing gaps, leading to improved service life and wear resistance of the plain bearings.

[0012] Furthermore, the flow channel may include a throttle element and / or a diffuser element in the outlet area. If the turbine-generator unit is used in essentially identical construction for different head heights or flow rates at, for example, different locations, a back pressure in the flow channel can be set by means of the throttle element and / or the diffuser element, so that the pressure difference of the cooling and lubricating fluid between the filter and conveying device and the flow channel can be adjusted to achieve effective cooling and sufficient lubrication of the sliding bearings.

[0013] Furthermore, it may be provided that several connecting channels are arranged circumferentially and each can be fluidically coupled to the flow channel. This allows the pressure distribution in the bearing gap to be homogenized, as the circumferentially distributed connecting channels promote a uniform outflow of the coolant and lubricant from the collection chamber into the flow channel.

[0014] Another advantageous design allows for the formation of several circumferentially distributed flow channels and several circumferentially distributed connecting channels, each fluidically coupled to a flow channel. In other words, a design is conceivable in which not a single central flow channel is provided, but rather several flow channels, each with a connecting channel to the collection chamber. This eliminates the need to construct the turbine shaft section by section as a hollow shaft with a central flow channel; instead, the individual circumferentially distributed flow channels can be formed as individual bores.This allows for a positive influence on the strength of the turbine shaft and, if necessary, the realization of a turbine shaft with a smaller maximum outer diameter than with a hollow shaft design. At the same time, the circumferentially distributed flow channels and their associated connecting channels promote a uniform outflow of the cooling and lubricating medium from the collection chamber.

[0015] According to a further development, the bearing arrangement can include a second hydrodynamic radial bearing axially spaced from the first radial bearing in the flow direction. This second radial bearing includes a fourth bearing gap, and the cooling and lubricating fluid can flow into a collection chamber located downstream of the bearings along the flow path of the cooling and lubricating fluid. By providing a second radial bearing axially spaced from the first radial bearing, the deflection of the turbine shaft can be reduced, resulting in a more homogeneous flow of cooling and lubricating fluid through the bearing gaps of all bearings. This, in turn, increases both the service life and the maintenance intervals of the turbine-generator unit.

[0016] Furthermore, it can be advantageous to have a second cooling and lubricating fluid inlet in the area where the turbine shaft is coupled to the turbine impeller, wherein the fourth bearing gap can be fluidically coupled to the second cooling and lubricating fluid inlet and the collection chamber, so that the fourth bearing gap can be supplied with cooling and lubricating fluid via the second cooling and lubricating fluid inlet, drawn from the operating medium flowing through the turbine-generator unit during operation. It is advantageous that, particularly in the case of an insufficient natural pressure differential between the inlet and outlet areas, as well as in the case of excessive throttling of the first, second, and third bearing gaps, the second radial plain bearing can be supplied with cooling and lubricating fluid via the second cooling and lubricating fluid inlet independently of the other plain bearings.This allows the sliding bearings of the bearing device to be operated advantageously and gently, especially when using the turbine-generator unit at low head heights.

[0017] Furthermore, it can be provided that the fourth bearing gap of the second radial plain bearing, following the third bearing gap, is sequentially or serially permeable to the cooling and lubricating fluid, which is extracted from the operating medium of the turbine-generator unit by means of the filter and conveying device. The advantage here is that the entire quantity of cooling and lubricating fluid is supplied by the filter and conveying device, thus allowing any potential contamination of the cooling and lubricating fluid to be addressed centrally at a single component or in a specific area of ​​the turbine-generator unit. With careful design of the filter and conveying device, this can significantly improve the service life and maintenance intervals of the turbine-generator unit, as well as the service life of the plain bearings.

[0018] Furthermore, the filter and conveying device may include a cover plate non-rotatably coupled to the turbine shaft, wherein a first cooling and lubricating fluid inlet is formed between the cover plate and the bearing assembly, and wherein the cover plate and / or the bearing assembly, in the area of ​​the cover plate, has at least one groove, a channel, a scraper, a rubber lip, or a similar guide element in the first cooling and lubricating fluid inlet, extending from a first radial distance towards a second radial distance that is larger relative to the first radial distance. It may therefore be advantageous if, for example, a recess is provided in the area of ​​the first cooling and lubricating fluid inlet on the cover plate or on the bearing assembly in the area of ​​the cover plate, which recess extends radially from the inside out relative to the turbine's axis of rotation.If the cover disc is rotatably coupled to the turbine shaft, a centrifugal force directed radially outwards relative to the turbine axis of rotation is created in the recess or, for example, when using a scraper. This removes sediments or other impurities from the operating medium or the cooling and lubricating fluid from the first cooling and lubricating fluid inlet.

[0019] In one particular design, the bearing gaps can be equipped with flushing grooves, where the initial gap width of the first cooling and lubricating fluid inlet is smaller than the depth of the flushing grooves. This effectively prevents clogging of the bearing gaps, leading to an improved service life for the plain bearings and thus for the entire turbine-generator unit. This measure is also economically advantageous compared to potentially complex filtration of the cooling and lubricating fluid.

[0020] According to a particularly advantageous embodiment, the filter and conveying device can include a conveying element that is rotaryally coupled to the turbine shaft, allowing the cooling and lubricating fluid to be supplied to the plain bearings to be conveyed to the first bearing gap. It is also conceivable that the conveying element is hydraulically coupled to the turbine shaft. The inclusion of a conveying element is advantageous because the pressure level of the cooling and lubricating fluid supplied to the plain bearings can be easily increased. Simultaneously, the rotary or hydraulic coupling of the conveying element to the turbine shaft eliminates the need for additional auxiliary equipment to provide the required conveying capacity, thus improving the efficiency of the turbine-generator unit.

[0021] In particular, it can be advantageous if the turbine-generator device comprises a flow guide device with guide elements, wherein the flow guide device is arranged in the flow direction between the at least one connecting element and the ring generator, wherein the guide elements are each mounted on the bearing device by means of a sliding bearing, and wherein the flow guide device is provided by means of a first adjusting device for actively controlling the flow to the turbine impeller.

[0022] This allows for simpler turbine blade and turbine impeller geometries in the hydraulic design, as the flow guide device, in conjunction with the turbine impeller, enables a hydraulically advantageous design of the hydraulic components. Consequently, the turbine-generator unit can be designed more compactly with regard to its axial extent, which in turn offers various advantages in terms of loads, deflections, and the required strength of the individual turbine-generator components. Regarding the bearing arrangement, turbine shaft deflections can be reduced, leading to an increased service life of the plain bearings and the associated advantages already described.

[0023] Furthermore, it can be provided that the entire turbine-generator unit is accommodated in the intake basin of the shaft power plant. It is advantageous that the entire turbine-generator unit is surrounded by the operating medium, thus ensuring a sufficient supply of cooling and lubricating fluid to the cooling and lubricating fluid inlets at all times during operation.

[0024] Furthermore, at least three connecting elements may be provided, whereby the bearing assembly is fixedly held in position on the ring housing by means of these at least three connecting elements. This allows for a particularly stable positioning of the bearing assembly relative to the ring housing, thereby improving the absorption and damping of vibrations induced by the turbine impeller or other hydraulic components. With regard to the bearing assembly, this measure in turn improves the service life of the turbine-generator unit.

[0025] Another advantageous configuration involves designing the ring generator of the turbine-generator unit as a synchronous generator, using permanent magnet poles and / or a brushless exciter in the ring generator rotor for excitation. This results in a more compact design of the turbine-generator unit and a reduced weight for the ring generator rotor, which, combined with lower turbine shaft deflection, protects the plain bearings.

[0026] According to further training, it is possible to design the ring generator with electronically controlled speed. Due to the adjustable speed of the turbine-generator unit, the resulting simplified hydraulic design allows for a more compact turbine-generator unit, which also reduces weight and, with less turbine shaft deflection, protects the plain bearings.

[0027] Furthermore, it can be advantageous for the turbine impeller to have rotatably mounted turbine blades, with the turbine blades being mounted on the ring generator rotor on one side and on the bearing assembly on the other, and the turbine blades being rotatable by means of a second adjustment device. This improves the controllability of the turbine-generator unit over a wider operating range, which in turn can lead to a simplified hydraulic design of the turbine-generator unit and thus provides or expands upon the advantages already mentioned.

[0028] Furthermore, the ring housing may be provided with a support device in the inlet area, whereby the turbine-generator unit can be supported against the bottom of the inlet basin by means of this support device. This increases the stability of the turbine-generator unit, which can have a particularly beneficial effect on the service life of the plain bearings.

[0029] To better understand the invention, it is explained in more detail with reference to the following figures.

[0030] They each show, in a highly simplified, schematic representation: Fig. 1 a shaft power plant with a first embodiment of a turbine-generator unit; Fig. 2 sectional view of the turbine-generator unit with a possible embodiment of the bearing device.

[0031] It should be noted at the outset that in the differently described embodiments, identical parts are provided with the same reference numerals or component designations, and the disclosures contained in the entire description can be applied analogously to identical parts with the same reference numerals or component designations. Furthermore, the positional designations chosen in the description, such as top, bottom, side, etc., refer to the figure directly described and illustrated, and these positional designations must be applied analogously to the new position if the position changes.

[0032] Fig. 1Figure 1 shows a shaft power plant 1 with a first embodiment of a turbine-generator unit 2, which may be independent. The turbine-generator unit 2 can be designed to generate electricity by converting the energy of a flow between an upstream water level 3 and a downstream water level 4. The turbine-generator unit 2 can be arranged in an intake basin 5 of the shaft power plant 1. The turbine-generator unit 2 can comprise an annular casing 6 with an inlet area 7 and an outlet area 8, wherein the flow between the upstream water level 3 or from the intake basin 5 of the shaft power plant 1 to the downstream water level 4 is conveyed through the annular casing 6 in the direction of flow 9 and thus through the turbine-generator unit 2.

[0033] Furthermore, the turbine-generator unit 2 can comprise a turbine impeller 10 with a turbine axis of rotation 11. The annular housing 6 can also have a teardrop-shaped or pear-shaped bearing device 12 in the inlet area 7, aligned along the turbine axis of rotation 11, wherein the bearing device 12 is fixedly connected or held to the annular housing 6 by means of at least one connecting element 13, or preferably four connecting elements 13. The turbine impeller 10 can be non-rotatably coupled to a turbine shaft 14 aligned along the turbine axis of rotation 11, wherein the turbine shaft 14 can be supported by means of the bearing device 12.

[0034] Furthermore, the turbine-generator unit 2 can comprise a ring generator 15 with a ring generator stator 16 and a ring generator rotor 17. The ring generator stator 16 can be rotationally fixed to the ring housing 6 in the run-out region 8, and the ring generator rotor 17 can be rotationally fixed to the turbine impeller 10 at an outer diameter, or to individual blades of the turbine impeller 10 at an outer diameter of the turbine impeller 10 that is radially distanced from the turbine axis of rotation 11, so that during operation of the turbine-generator unit 2, the ring generator rotor 17 rotates about the turbine axis of rotation 11 relative to the ring generator stator 16 when the turbine impeller 10 rotates.

[0035] With regard to the turbine impeller 10, it is conceivable that it may have rotatably mounted turbine blades, wherein the turbine blades may be rotatably mounted on the ring generator rotor 17 and on a hub coupled to the turbine shaft 14.

[0036] Furthermore, the ring generator 15 can be configured as a synchronous generator, wherein the ring generator rotor 17 can comprise permanent magnet poles and / or a brushless exciter for excitation. Additionally, the ring generator 15 can be configured to have its speed controlled by means of an electronic control device.

[0037] Furthermore, the turbine-generator unit 2 can comprise a support element 18 with a connection surface 19. The support element 18 can be arranged downstream of the ring generator stator 16 or the ring generator 15 in the flow direction 9 and be rotationally fixed to the ring generator stator 16. Thus, the turbine-generator unit 2 can be mounted on the support element 18. The turbine-generator unit 2 can be movable at least between a maintenance position and an operating position, wherein, when positioned in the maintenance position, the turbine-generator unit 2 is preferably positioned above the underwater level 4, and when positioned in the operating position, the turbine-generator unit 2 is positioned such that the outflow between the upstream and downstream water levels through the turbine-generator unit 2 can be fluidically coupled to the downstream water level via a suction pipe 20 or a flow channel.When the turbine-generator unit 2 is positioned in the operating position, the support element 18 can be designed such that the connection surface 19 comes into contact with, for example, a counter-connection surface 21 situated on the structure of the shaft power plant 1 or with a wall section of the inlet basin 5 facing the underwater area, or is pressed against it.

[0038] Furthermore, the turbine-generator unit 2 may include a flow guide device 22 with individual guide elements 23 or guide vanes. The flow guide device 22 may be arranged downstream of the at least one connecting element 13(s) in the flow direction 9. The guide elements 23 may extend from the surface of the bearing device 12 to an inner surface of the annular housing 6, and may be cantilevered on the bearing device 12 or mounted on the annular housing 6. The flow guide device 22 may include an adjustment device, such as a regulating ring, by means of which the guide elements 23 can be adjusted to ensure or enable active control of the flow to the turbine impeller 10.

[0039] It may also be provided that the turbine-generator unit 2 or the ring housing 6 in the inlet area 7 includes a support device 24, wherein the turbine-generator unit 2 can be supported on the bottom 25 of the inlet basin 5 by means of the support device 24.

[0040] Fig. 2 Figure 1 shows a sectional view of the turbine-generator unit 2 with a possible embodiment of the bearing device 12, where the same reference numerals or component designations are used for identical parts as in the preceding figure. Fig. 1 to be used. To avoid unnecessary repetition, reference is made to the detailed description in the preceding section. Fig. 1 pointed out or referenced.

[0041] As in Fig. 2The bearing arrangement 12 of the turbine-generator unit 2 can, as shown, comprise a first hydrodynamic axial sliding bearing 26, a second hydrodynamic axial sliding bearing 27, and a first hydrodynamic radial sliding bearing 28a. The second axial sliding bearing 27 can be spaced apart from the first axial sliding bearing 26 in the direction of the turbine's axis of rotation 11. The turbine shaft 14 is supported by means of the sliding bearings 26, 27, and 28. The turbine impeller 10 can be non-rotatably coupled to the turbine shaft 14.

[0042] Furthermore, the bearing assembly 12 of the turbine-generator unit 2 can comprise a filter and conveying device 30 at a first axial end face 29 in the inlet area 7. The filter and conveying device 30 can be configured to extract cooling and lubricating fluid from the operating medium flowing through the turbine-generator unit 2 in order to supply this cooling and lubricating fluid to the sliding bearings 26, 27, 28. For this purpose, the filter and conveying device 30 can comprise a cover plate 38 rotationally fixed to the turbine shaft 14, wherein a first cooling and lubricating fluid inlet 39 is formed between the cover plate 38 and the bearing assembly 12, by means of which cooling and lubricating fluid can be extracted from the operating medium flowing through the turbine-generator unit 2 during operation.It may be provided that the cover plate comprises at least one groove, notch, recess, rubber lip, scraper or similar guide element extending radially from the inside to the outside with respect to the turbine axis of rotation 11, wherein this guide element is formed in the first cooling and lubricating fluid inlet 39, or is formed in such a way that the flow pattern in the first cooling and lubricating fluid inlet 39 can be influenced by it.

[0043] As from Fig. 2As can be seen, the plain bearings 26, 27, 28 can be arranged such that, starting from the filter and conveying device 30, first a first bearing gap 31 of the first axial plain bearing 26, followed by a second bearing gap 32 of the second axial plain bearing 27 and followed by a third bearing gap 33 of the first radial plain bearing 28a, is sequentially or serially supplied with cooling and lubricating fluid.It may be provided that the bearing gap spaces 31, 32, 33 each comprise at least one groove, notch, recess, rubber lip, scraper or similar flushing element, wherein the respective flushing element limits or expands the cross-section of the respective bearing gap space 31, 32 or 33 at the point of formation of the flushing element such that a first gap width of the first cooling and lubricating fluid inlet 39 is smaller than a cross-sectional dimension in the radial direction of the respective bearing gap space 31, 32 or 33 at the point of formation of the flushing element.

[0044] The filter and conveying device 30 can also include a conveying element 40 which is rotary-energetically and / or hydraulically coupled to the turbine shaft 14 in order to increase the pressure level of the cooling and lubricating fluid received from the first cooling and lubricating fluid inlet 39 and / or to supply the cooling and lubricating fluid to the sliding bearings 26, 27, 28 or initially to the first bearing gap 31 and subsequently to the other bearing gaps.

[0045] Furthermore, the bearing arrangement 12 of the turbine-generator unit 2 can include a collection chamber 35 for the cooling and lubricating fluid. The collection chamber 35 can be located downstream or downstream of the plain bearings 26, 27, 28 with respect to the flow path 34 of the cooling and lubricating fluid. At least one flow channel 36 can be formed in the turbine shaft 14, wherein the at least one flow channel 36 extends substantially in the direction of the turbine's axis of rotation 11. Furthermore, the flow channel 36 can be formed at least partially in the turbine shaft 14, wherein the flow channel 36 has an opening 41 at least in the outlet region 8 of the turbine-generator unit 2, so that the flow channel 36 can be fluidically coupled to the outlet region 8. Furthermore, a connecting channel 37 can be formed in the turbine shaft 14, whereby the collecting chamber 35 and the flow channel 36 can be fluidically coupled by means of the connecting channel 37.

[0046] One embodiment of the turbine-generator device 2 is conceivable in which the turbine shaft 14 comprises several flow channels 36, which are formed in the turbine shaft 14 essentially parallel to the turbine axis of rotation 11, and a connecting channel 37 for each flow channel 36, wherein the flow channels 36 and the respective associated connecting channels 37 are distributed circumferentially in the turbine shaft 14. Likewise, another embodiment of the turbine-generator device 2 is conceivable in which the turbine shaft 14 comprises a flow channel 36, which is arranged centrally in the turbine shaft 14, such that the turbine shaft 14 is formed at least partially as a hollow shaft. This possible further embodiment is described in Fig. 2As shown. In any case, the described configurations of the turbine-generator unit 2 and the possible configurations of the bearing device 12 ensure that a natural pressure difference between the inlet area 7 and the outlet area 8 can be used as the main driving force for flushing the sliding bearings 26, 27, 28 with cooling and lubricating fluid taken from the operating medium of the turbine-generator unit 2.

[0047] In the area of ​​opening 41, the flow channel 36 can also include a throttle element 42 and / or a diffuser element 43 to influence the natural pressure difference between inlet area 7 and outlet area 8 for flushing the sliding bearings 26, 27, 28. This can be advantageous, for example, if an identical turbine-generator unit 2 is used for different head chambers and flow rates, in order to fine-tune the usable pressure difference for flushing the sliding bearings 26, 27, 28 according to the different conditions or installation requirements by means of the throttle element 42 and / or the diffuser element 43.

[0048] As in Fig. 2The bearing device 12 can, as shown, comprise a second hydrodynamic radial plain bearing 28b with a fourth bearing gap 45. The collecting chamber 35 can, as already described, be arranged such that the plain bearings 26, 27, 28, including the second radial plain bearing 28b, can be sequentially or serially supplied with cooling and lubricating fluid, and the cooling and lubricating fluid can be received in the collecting chamber 35 in order to be discharged via the connecting channel 37 and the flow channel 36 into the outlet area 8.

[0049] As in Fig. 2However, an embodiment is also possible in which a second cooling and lubricating fluid inlet 44 is provided, wherein cooling and lubricating fluid can again be drawn from the operating medium flowing through the turbine-generator unit 2 during operation by means of the second cooling and lubricating fluid inlet 44. Thus, the fourth bearing gap chamber 45 can be supplied with cooling and lubricating fluid by means of the second cooling and lubricating fluid inlet 44, wherein the cooling and lubricating fluid, as before and as in Fig. 2 shown in which the cooling and lubricating fluid can flow into the collection chamber 35 following or downstream of the sliding bearings 26, 27, 28 along the flow path 34, in order to be able to be discharged into the outlet area 8 via the connecting channel 37 and the flow channel 36.

[0050] The exemplary embodiments show possible embodiment variants, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiment variants, but rather various combinations of the individual embodiment variants are also possible and this possibility of variation lies within the skill of the person skilled in this technical field due to the teaching on technical action by the present invention.

[0051] The scope of protection is defined by the claims. However, the description and drawings must be consulted for the interpretation of the claims. Individual features or combinations of features from the different embodiments shown and described can, in themselves, represent independent inventive solutions. The problem underlying these independent inventive solutions can be found in the description.

[0052] All references to value ranges in this description are to be understood as encompassing any and all sub-ranges thereof, e.g., the reference 1 to 10 is to be understood as including all sub-ranges, starting from the lower limit 1 and the upper limit 10, i.e., all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g., 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0053] Finally, for the sake of clarity, it should be noted that, for a better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced in size. Reference numeral list

[0054] 1 Shaft power plant 30 Filter and conveying device 2 Turbine generator unit 31 first storage gap 3 Upstream water level 32 second storage gap 4 Underwater level 33 third storage gap 5 Inlet basin 34 Flow path of the cooling and lubricating fluid 6 Ring case 7 Entrance area 35 Collection room 8 Run-off area 36 Flow channel 9 Flow direction 37 Connection channel 10 Turbine wheel 38 Cover plate 11 Turbine axis of rotation 39 first cooling and lubricating fluid inlet 12 Storage device 13 Connecting element 40 Funding body 14 Turbine shaft 41 opening 15 Ring generator 42 Throttle element 16 Ring generator stator 43 Diffuser element 17 Ring generator rotor 44 second cooling and lubricating fluid inlet 18 Supporting element 19 Connection surface 45 fourth storage gap 20 Intake manifold 21 Counter-connection surface 22 Flow guide device 23 Guide elements 24 Support device 25 Floor 26 first axial plain bearing 27 second axial sliding bearing 28 radial plain bearings 29 forehead

Claims

1. A turbine-generator unit (2) for generating electricity by energy conversion of an outflow between a headwater with a headwater level (3) and a tailwater with a tailwater level (4) in a pit-type hydropower plant (1) with an intake basin (5), the turbine-generator unit (2) comprising a rim-shaped housing (6) with an inlet region (7) and an outlet region (8), a rim-type generator (15), and a turbine impeller (10) with a turbine axis of rotation (11), - wherein the rim-shaped housing (6) in the inlet region (7) comprises a pear-shaped bearing device (12) aligned along the turbine axis of rotation (11), -- wherein the bearing device (12) is held in a fixed position on the rim-shaped housing (6) by means of at least one connecting element (13), -- wherein the bearing device (12) comprises a first hydrodynamic axial sliding bearing (26), a second hydrodynamic axial sliding bearing (27) spaced from the first axial sliding bearing (26) in the direction of the turbine axis of rotation (11) and a first hydrodynamic radial sliding bearing (28a), wherein a turbine shaft (14) aligned along the turbine axis of rotation (11) is mounted by means of the sliding bearings (26, 27, 28), wherein the turbine impeller (10) is coupled to the turbine shaft (14) in the outlet region (8) in a rotationally fixed manner, and -- wherein a filtering and conveying device (30) for the cooling and lubricating fluid to be supplied to the sliding bearings (26, 27, 28) is formed in the inlet region (7) at a first axial end face (29) of the bearing device (12), - wherein a first bearing gap space (31) of the first axial sliding bearing (26), subsequently a second bearing gap space (32) of the second axial sliding bearing (27) and subsequently a third bearing gap space (33) of the first radial sliding bearing (28a) can be flown through sequentially by the cooling and lubricating liquid, -- wherein the cooling and lubricating fluid can flow into a collecting chamber (35) following and / or being located downstream of the sliding bearings (26, 27, 28) along the flow path (34) of the cooling and lubricating fluid, characterized in that - the turbine shaft (14) in some sections has a flow channel (36) aligned essentially parallel to the turbine axis of rotation (11), -- wherein the flow channel (36) is fluidically couplable to the operating medium flowing through the turbine-generator unit (2) in the outlet region (8) of the turbine-generator unit (2) and / or in the region of the coupling of the turbine shaft (14) to the turbine impeller (10), and -- the turbine shaft (14) has a connecting channel (37) which can be fluidically coupled to the flow channel (36) and the collecting chamber (35), so that the cooling and lubricating fluid can flow through the bearing device (12).

2. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the flow channel (36) is formed along the turbine axis of rotation (11) and being rotationally symmetrical to the turbine axis of rotation (11).

3. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the flow channel (36) comprises a throttle element (42) and / or a diffuser element (43) in the outlet region (8).

4. The turbine-generator unit (2) according to one of the preceding claims, characterized in that multiple connecting channels (37) are formed, which are arranged distributed in the circumferential direction and can each be fluidically coupled to the flow channel (36).

5. The turbine-generator unit (2) according to claim 1, characterized in that multiple flow channels (36), which are arranged distributed in the circumferential direction, are formed and multiple connecting channels (37), which are arranged distributed in the circumferential direction and are each fluidically couplable to a flow channel (36), are formed.

6. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the bearing device (12) comprises a second hydrodynamic radial sliding bearing (28b) axially spaced from the first radial sliding bearing (28a) in the flow direction (9), wherein the second radial sliding bearing (28b) comprises a fourth bearing gap space (45), wherein the cooling and lubricating fluid can flow into a collecting chamber (35) following and / or being located downstream of the sliding bearings (26, 27, 28) along the flow path (34) of the cooling and lubricating fluid.

7. The turbine-generator unit (2) according to claim 6, characterized in that a second cooling and lubricating fluid inlet (44) is formed in the region of the coupling of the turbine shaft (14) to the turbine impeller (10), wherein the fourth bearing gap space (45) is fluidically couplable to the second cooling and lubricating fluid inlet (44) and the collecting chamber (35), so that by means of the second cooling and lubricating fluid inlet (44) the fourth bearing gap space (45) can be flown through with cooling and lubricating fluid taken from the operating medium flowing through the turbine-generator device (2) during operation.

8. The turbine-generator unit (2) according to claim 6, characterized in that the fourth bearing gap space (45) of the second radial sliding bearing (28b) can be flown through sequentially and / or in series following the third bearing gap space (33) by the cooling and lubricating fluid, which can be taken from the operating medium of the turbine-generator unit (2) by means of the filtering and conveying device (30).

9. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the filtering and conveying device (30) comprises a cover plate (38) coupled in a rotationally fixed manner to the turbine shaft (14), wherein a first cooling and lubricating fluid inlet (39) is formed between the cover plate (38) and the bearing device (12), and wherein the cover disk (38) and / or the bearing device (12), in the region of the cover disk (38), starting from a first radial distance in the direction of a second radial distance which is greater relative to the first radial distance, has at least one groove, a gouge, a wiper, a rubber lip or a similar guide member in the first cooling and lubricating fluid inlet (39).

10. The turbine-generator unit (2) according to claim 9, characterized in that the bearing gap spaces (31, 32, 33) have flushing grooves, wherein a first gap width of the first cooling and lubricating fluid inlet (39) is smaller than a depth of the flushing grooves.

11. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the filtering and conveying device (30) comprises a conveying member (40) which is rotationally-energetically coupled to the turbine shaft (14), wherein the cooling and lubricating fluid to be supplied to the sliding bearings (26, 27, 28) is conveyable to the first bearing gap space (31).

12. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the turbine-generator unit (2) comprises a flow guide device (22) with guiding elements (23), wherein the flow guide device (22) is arranged in the flow direction (9) between the at least one connecting element (13) and the rim-type generator (15), wherein the guiding elements are each mounted on the bearing device (12) by means of a sliding bearing, wherein the flow guide device (22) is provided for actively controlling the flow towards the turbine impeller (10) by means of a first adjusting device.

13. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the turbine-generator unit (2) is receivable in its entirety in the intake basin (5) of the pit-type hydropower plant (1).

14. The turbine-generator unit (2) according to one of the preceding claims, characterized in that at least three connecting elements (13) are formed, wherein the bearing device (12) is held in a fixed position on the rim-shaped housing (6) by means of the at least three connecting elements (13).

15. The turbine-generator unit (2) according to one of the preceding claims, characterized in that the rim-type generator (15) of the turbine-generator unit (2) is configured as a synchronous generator, wherein permanent-magnet poles and / or a brushless excitation machine is / are provided as excitation in the rim generator rotor (17).

16. The turbine-generator unit (2) according to claim 14, characterized in that the rim-type generator (15) is configured to be speed-controllable by means of an electronic control device.

17. The turbine-generator unit (1) according to one of the preceding claims, characterized in that the turbine impeller (10) has rotatably mounted turbine blades, wherein the turbine blades are mounted on the rim generator rotor (17) on the one hand and are mounted on the bearing device (12) on the other hand, wherein the turbine blades are rotatable in the bearing device (12) by means of a second adjusting device.

18. The turbine-generator unit (1) according to one of the preceding claims, characterized in that the rim-shaped housing (6) has a supporting device (24) in the inlet region (7), wherein the turbine-generator unit (1) can be supported on a bottom (25) of the intake basin (5) by means of the supporting device (24).

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