Vertical axis hydro turbine with vertically pivoting blades

Abstract

Vertical axis hydro turbine with vertically pivoting blades Hydro turbine, intended to be immersed in an aquatic environment animated by a current, comprising a rotor with a vertical axis of rotation, the rotor comprising: - a central hub oriented vertically, - a frame rotating with the hub, - a plurality of blades articulated on the frame, each pivotally mounted on the frame around a respective vertical geometric axis of rotation with limited angular movement relative to the frame, between a working position where the angle is zero and a position of maximum movement where the angle is less than or equal to 225°. Figure for the abstract: Fig. 1

Description

Title of the invention: Vertical axis hydro turbine with vertically pivoting blades Technical field

[0001] The present invention relates to the field of hydro turbines and more precisely to the field of vertical axis hydro turbines equipped with vertically pivoting blades. Prior art

[0002] River and marine currents, waves and tides constitute one of the most widespread sources of renewable energy in the world. Having a limited visual impact, tidal turbines also have the advantage, due to the fact that the density of water is 850 times greater than that of air, of being much smaller than wind turbines for equivalent power. Furthermore, due to the incompressible nature of liquids like water, unlike gases like air, tidal turbines have the specific feature of being operational at very low rotation speeds compared to wind turbines. Faced with ecological awareness, their deployment has thus experienced a real boom over the last ten years.

[0003] The majority of hydro turbines are in the form of horizontal axis turbines using the propeller principle, i.e. blades, inclined or curved surfaces, arranged regularly around a horizontal hub. Vertical axis hydro turbines are also known from the prior art, notably inspired by Darrieus or Savonius type wind turbines.

[0004] Panemones or rotating sail wind turbines, known since the early Middle Ages, have also influenced the development of another type of vertical axis hydro turbines, characterized by the dynamic optimization of the blade setting according to their position. In this type of hydro turbine, the blades behave like the sail of a sailboat that would make a circle in the water with a determined wind. They can pivot to adjust in real time to all the speeds that the sailboat would follow heading to the different capes, the blades being oriented according to the wind experienced as would be the sail of the boat. By this rotation of the blades, the hydro turbine can thus maximize the energy received from the current, the drag of the blades in the direction of the current being considerably reduced.

[0005] Nevertheless, hydro turbines inspired by panemones are faced with several problems. First of all, it is necessary to ensure that the blades pushed and set in motion by the fluid receive a significantly greater thrust than those returning from the other side and which undergo a thrust contrary to the movement. It is this differential thrust on each side of the vertical axis which generates the movement. In the original panemones, deflectors protect the blades that are facing the wind and direct the wind to the driving thrust side. This system is effective but only works for a fixed direction of the driving fluid. In the case of Darrieus or Savonius type wind turbines, it is the shape of the blade that provides a wind resistance differential depending on the side facing the wind. However, since this differential is small, the efficiency is low.

[0006] For hydro turbines inspired by panemones, it is thus necessary to have complex mechanisms to allow the rotor of the hydro turbine to move, but also to prevent all the blades from feathering during its operation, in particular during a change in the direction of the current, i.e. the plane of each blade from merging with the direction of the current, which would cause the device to become immobilized.

[0007] GB2435905 discloses a vertical axis rotary wing hydro turbine in which Two discs are connected by vertical uprights around which pivoting blades are articulated. In the center of this structure, other blades are arranged to prevent the hydro turbine from stalling in the event of a change in the direction of the current.

[0008] In application GB2452484 a Savonius type turbine is arranged below the structure of a hydro turbine consisting of two discs connected by uprights around which pivoting blades are articulated. The presence of a Savonius type turbine makes it possible both to initiate the rotation of the rotor of the hydro turbine and also to prevent it from stalling.

[0009] Applications GB2435905 and GB2452484 also disclose internal stops which allow the transfer of the support forces exerted by the currents on the blades onto the rotating frame, thus causing it to rotate. These stops also play a second role by preventing the blades from rotating completely in one direction around their respective axes. They thus prevent all the blades from feathering in the direction of the current.

[0010] However, the presence of internal blades or another type of turbine in the center of the hydro turbine to initiate movement and prevent the device from becoming immobilized in the event of a change in the direction of the current implies a reduction in the dimensions of the external blades and therefore a reduction in the efficiency of the hydro turbine.

[0011] Furthermore, the Savonius turbine alone has poor efficiency. By placing a Savonius type turbine under the structure supporting the pivoting blades, as in application GB2452484, the overall operation of the hydro turbine is affected and its efficiency is significantly reduced.

[0012] Finally, if the internal stops, in addition to a transfer of forces, prevent the blades from feathering for a specific direction of current, they cannot, however, prevent this phenomenon in the event of a change in direction of the current.

[0013] There is thus a need for a simple structure of a hydro turbine with a vertical axis and vertically pivoting blades, with a higher efficiency, than the simple mechanism, which would not encounter difficulties in initiating rotation of the rotor and would not be subject to immobilization phenomena, in particular in the event of a change in the direction of the current. Summary of the invention

[0014] The invention aims to meet this need and has as its subject, according to one of its aspects, a hydro turbine intended to be immersed in an aquatic environment animated by at least one current, comprising a rotor with a vertical axis of rotation, the rotor comprising: - a vertically oriented central hub, - a rotating chassis with the hub, - a plurality of blades articulated on the frame, each pivotally mounted on the frame around a respective vertical geometric axis of rotation with limited angular movement relative to the frame, between a working position where the angle is zero and a position of maximum movement where the angle is less than or equal to 225°.

[0015] By "working position", it is meant that the blade extends substantially in the plane formed by its geometric axis of rotation and the axis of rotation of the rotor, its free end being close to the hub, so that when the blade is in opposition to the current, the current exerts a thrust on the blade generating a torque which drives the rotor in rotation.

[0016] By “maximum travel position” is meant a position of the blade such that its angular travel relative to the working position is maximum.

[0017] Advantageously, during a change in the direction of the current, the blades of the hydro turbine according to the invention pivot, with some of the blades feathering while the rest of the blades are locked in their maximum travel position. Limiting the angular travel of the blades to an angle less than or equal to 225° thus makes it possible to avoid a configuration where all of the blades would feather following a change in the direction of the current, thereby leading to immobilization of the hydro turbine. This also makes it possible to generate strong thrust and a significant torque which is added to the rotation of the assembly, guaranteeing the initiation or maintenance of the rotation of the assembly regardless of changes in the orientation of the currents.

[0018] During operation of the hydro turbine, the current exerts a thrust on the blade(s) in the working position as well as on those in the maximum travel position, which generates a torque which sets the entire rotor in rotation, which itself drives an electricity generator.

[0019] In the hydro turbine according to the invention, there is therefore no need for an additional structure, internal such as a second set of blades, or located under the blades such as a Savonius turbine, to initiate the movement and prevent immobilization in the event of a change in the direction of the current. This contributes to improving the efficiency compared to the structures known from the prior art, by optimizing the size of the blades and avoiding parasitic flows of low efficiency. This absence of an additional mechanism or structure leaves complete freedom in the dimensioning of the blades, both in their dimensions themselves and in their height-width ratio, thus allowing all formats and applications depending on the topography of the installation areas.Indeed, very wide blades with low heights can be efficient in weak currents and low water depths while blades with great heights and low widths will be suitable for fast currents. All combinations of sizes and ratios are possible. Depending on the formats and height / width ratios, these tidal turbines according to the invention will be suitable for use in underwater farms in open plains as well as in corridors or channels crossed by currents. In addition, the manufacture and maintenance of the tidal turbine are simplified by limiting the number of parts. Since the transfer of kinetic energy from the fluid to the tidal turbine is carried out by a direct frontal thrust with almost no counter-thrust, nor by pressure differentials linked to the flows on the surface of the blades, the condition of the surfaces has little impact on the efficiency.Indeed, any object immersed for a long period in water undergoes concretion phenomena, which generates friction or turbulence on laminar flows reducing productivity in other processes. By limiting the number of parts and preventing a secondary flow with another turbine, the hydro turbine according to the invention thus limits disturbances and maintains higher efficiency over time. Rotor

[0020] The axis of rotation of the rotor is oriented vertically along a Z axis.

[0021] The hub may have the same geometric axis of rotation as the rotor.

[0022] The rotor hub may take the form of a vertical mast, on which is mounted the chassis.

[0023] The hub can support an electricity generator. This generator can be arranged at the foot of the hub.

[0024] Alternatively, the generator can be integrated into the hub, in particular over its entire height. The absence of elements, in particular axles, passing through the hub makes it possible to integrate an electricity generating mechanism over its entire height.

[0025] The generator may have an external rotor.

[0026] When the hydro turbine is operating, the rotor rotates and drives the generator to produce electricity.

[0027] A submerged cable for transporting electrical energy can be connected to the generator. This cable can be laid on the ground or buried.

[0028] The rotor can be characterized by its diameter D. D is twice the maximum distance that can exist during operation of the rotor between the axis of rotation of the rotor and the free end of a blade.

[0029] D may in particular be between 0.2 and 10 m, better between 1 and 5 m, so that the nominal power of the hydro turbine in kilowatts (kW), which depends directly on the diameter of the rotor, is between 50 kW and 3000 kW, better is greater than 1000 kW.

[0030] The diameter d of the hub depends on the overall diameter D of the rotor and the current generating equipment. It can in particular be between 0.2 and 4 m. The hub can have a variable diameter over its entire height. Stator

[0031] The stator of the hydro turbine can be fixed to a base, which can be buried or kept fixed, for example by being secured to a wider or multi-branch fixed support.

[0032] The hydro turbine may comprise a gantry, arranged so as to encompass the chassis by connecting the upper end of the hub to a base of the hydro turbine.

[0033] The gantry may comprise a set of arms, in particular in the shape of a cross, extending from the upper end of the hub to the base of the hydro turbine.

[0034] The gantry may hold the hub at its upper end by means of ball bearings or roller bearings.

[0035] The presence of a gantry, by holding the hub, contributes to protecting the integrity of the hydro turbine device. Chassis

[0036] The frame may extend radially around the hub.

[0037] The radius R of the chassis can be between 0.25 m and 30 m, better between 2 and 10 m.

[0038] The blades can rotate freely around their joints.

[0039] The rotation of the blades can be guided by bearings, in particular ball bearings.

[0040] The axes of rotation of the blades may be equidistant from the axis of rotation of the hub, in particular angularly equidistant.

[0041] The number of blades is preferably equal to four.

[0042] Preferably, the chassis comprises an upper part and a lower part connected by the hub.

[0043] Vertical uprights may extend along the axes of rotation of the blades between the upper and lower parts of the frame. Alternatively, the upper and lower parts have bearings on which pivots for articulating the blades engage.

[0044] The chassis may have two sets of arms, in particular in the form of a cross, extending from the hub.

[0045] The rotor may have only one stage of blades. Alternatively, the rotor has several stages of blades. The axes of rotation of the blades of the different stages may be angularly offset from one stage to another, to reduce the number of blades in feathering at the same time.

[0046] The chassis may comprise at least one reinforcing structure, arranged to connect together several arms extending from the hub.

[0047] Preferably, there are two reinforcing structures, one for each of the sets of cross-shaped arms extending from the hub.

[0048] The structure(s) may comprise one or more parts.

[0049] The reinforcement structure(s) may take various forms, in particular that of a square.

[0050] The chassis may be made at least partially of plastic or composite material. It can also be made at least partially of metal, in particular stainless steel or aluminum. Alternatively, it is made of another material, suitable for its proper functioning.

[0051] The chassis may have a transverse plane of symmetry, it may also have at least one longitudinal plane of symmetry. The chassis may also have axial symmetry.

[0052] The various elements of the chassis can be solid or hollow, so as to modify the density of the assembly and approach neutral buoyancy in order to reduce friction and wear of the bearings and rotation devices. Stops

[0053] The angular movement of each blade relative to the frame can be limited by different methods, in particular by the presence of at least two stops. These stops can be located on the frame, but also on the blades.

[0054] The frame may comprise at least two stops to limit the angular movement of each blade relative to the frame. The angular movement of each blade relative to the frame may be limited by at least one internal stop and by at least one peripheral stop. The angular travel of each blade may be limited to an angle less than or equal to 225°, better still less than or equal to 200°, for example 180°.

[0055] By "peripheral stop" is meant a stop located on the frame near the periphery of the rotor, as opposed to an "internal" stop, closer to the central hub of the rotor. When the blades are in the working position, they come to bear against the internal stop(s), which restrict their rotational movement relative to the frame and allow the transmission of the driving force generated by the blades to the frame, itself fixed to the rotor.

[0056] When the blades are in the maximum travel position, they come to bear against the peripheral stops, which prevent them from opening further.

[0057] The internal stop(s) may be arranged at a distance di from the geometric axis of rotation of the central hub.

[0058] The peripheral stop(s) may be arranged at a distance d2 from the geometric axis of rotation of the central hub, with d2 greater than dh

[0059] The stops can act by constituting an obstacle to the movement of the blades.

[0060] Preferably, the frame comprises at least one internal stop and at least one peripheral stop for each blade.

[0061] The frame may comprise one or more internal stops dedicated to each blade. The internal stops may be arranged on the upper part of the frame and / or on the lower part of the frame. Preferably, each blade is dedicated to two internal stops, one located on the upper part of the frame and another located on the lower part of the frame, in particular arranged symmetrically along a transverse plane of the frame. This positioning makes it possible to distribute the support forces well over the entire frame.

[0062] Similarly, there may be one or more peripheral stops dedicated to each blade. The peripheral stops may be arranged on the upper part of the frame and / or on the lower part of the frame. Preferably, each blade has two peripheral stops dedicated to it, one located on the upper part of the frame and another located on the lower part of the frame, in particular arranged symmetrically along a transverse plane of the frame. This positioning makes it possible to distribute the support forces well over the entire frame.

[0063] The internal stops may all have the same shape, in particular rectangular, and the same dimensions.

[0064] The peripheral stops may all have the same shape, in particular rectangular, and the same dimensions.

[0065] The inner and outer stops may have the same shape and dimensions. Alternatively, they have different shapes and / or dimensions.

[0066] The stops may incorporate a damping element, for example a pad made of elastomeric material, or an end-of-travel spring. These damping elements contribute to absorbing shocks and reducing noise when the blade rests on the stop(s).

[0067] The dimensions of the peripheral stop(s) are chosen to withstand the thrusts and stresses during use, taking into account the material used.

[0068] The position and dimensions of said stops, in particular their thickness eb, can vary to constrain the angular movement to a precise angle 0, less than or equal to 225°.

[0069] The angle S is chosen to maximize efficiency. This parameter depends on the viscosity of the liquid and the average speed of the current driving the blades.

[0070] In another embodiment, the angular movement of each blade relative to the frame is limited by at least two stops and at least one stop is integrated into a joint or a face of the blade.

[0071] The stop(s) may in particular be formed by a protrusion, in particular a lug, or a shoulder present on the blades.

[0072] These stops can rest on the frame when the blades are in the maximum travel or working position. Blades

[0073] The blades may have a substantially rectangular contour when viewed from the front. Alternatively, the blades may have another contour; the blades may be substantially flat or non-flat, in particular left-handed. The blades may have worked profiles, in particular a shape having a curvature like an airplane wing, in particular with rounded corners, chamfers or bevels optimizing hydrodynamics and discouraging the formation of concretion or plant or animal colonies.

[0074] The section of each blade may have, in cross-section at least from a certain distance from its axis of rotation, a thickness which decreases as it moves away from the axis of rotation.

[0075] Each blade may have a profile, in particular near its free end, tending to promote the creation of a torque causing the blade to pivot out of the working position while the chassis rotates.

[0076] The profile may have the shape of a bevel present on the upstream face of the blade, preferably extending over one fifth of the length of the blade.

[0077] The term “upstream face” of a blade refers to the face that the current first encounters when it is in the working position.

[0078] The presence of a bevel can reduce drag when the blade comes off a stop. It can facilitate the initiation of rotation of the blades.

[0079] Each blade may have an overhang arranged to come into contact with at least one respective peripheral stop when the blade is in a position of maximum travel.

[0080] The positioning of the peripheral stop(s), in particular the distance d2, is chosen as a function of the width 15 of the overhang.

[0081] The support of the overhang on the stop allows the blade to be locked in its maximum travel position.

[0082] The overhang may have a shoulder which rests on the peripheral stop(s) when the blade is in a position of maximum travel.

[0083] The dimensions of the shoulder can vary to influence the angular deflection of the blades. The combination of the dimensioning of the shoulder and the peripheral stop allows the maximum angular deflection of the blades to be varied.

[0084] This shoulder can be made over the entire height of the blade or only over a portion of it.

[0085] Each blade may have for each respective peripheral stop a corresponding recess in which the stop engages when the blade is in the working position, so that the blade can be substantially aligned between its geometric axis of rotation and the axis of rotation (Z) of the rotor.

[0086] These recesses allow the blade to come to rest fully on the inner stop(s) without striking, resting on or getting stuck on the outer stop.

[0087] The recesses may have a shape that substantially matches the shape of the stop. Alternatively, they have a different shape, wider than the stops.

[0088] The blades can be solid, hollow or honeycombed. This makes it possible to modify their density and approach neutral buoyancy in order to reduce friction and wear on bearings and rotation devices. Electricity production process

[0089] The invention also relates to a method for producing electricity using a hydro turbine according to the invention, in which the rotor drives an electricity generator in rotation. Brief description of the drawings

[0090] The invention may be better understood by reading the following description, non-limiting examples of implementation of the invention, and by examining the attached drawing, in which:

[0091] [Fig.l] [Fig.l] is a schematic and partial perspective view of the hydro turbine,

[0092] [Fig.2] [Fig.2] is a schematic top view of the hydro turbine of [Fig.l],

[0093] [Fig.3] [Fig.3] is a set of schematic top views of the hydro turbine of [Fig.l] illustrating its operation,

[0094] [Fig.4] [Fig.4] is a pair of schematic top views of the hydro turbine of [Fig.l] illustrating its operation when the direction of the current reverses,

[0095] [Fig.5] [Fig.5] is a schematic detailed view of [Fig.4] b),

[0096] [Fig.6] [Fig.6] is a set of schematic top views of the hydro turbine of [Fig.l],

[0097] [Fig.7] [Fig.7] is a schematic side view of the hydro turbine of [Fig.l] in operating condition,

[0098] [Fig.8] [Fig.8] is a schematic profile view of the hydro turbine comprising a gantry and a reinforcement structure. Detailed description

[0099] [Fig.l] illustrates a hydro turbine 1 according to the invention.

[0100] The hydro turbine 1 comprises a rotor 2 with a vertical axis Z, this rotor 2 comprising a hub 3 oriented vertically along the axis Z and a frame 4 mounted on the hub. The hydro turbine 1 is fixed to a base 5, intended to be buried or kept fixed.

[0101] The hub 3 may have an electricity generator 6 at its base.

[0102] The chassis 4 has two sets of arms 7 and 8 in the form of a cross mounted on the central hub 3.

[0103] The geometric axis U of rotation of each blade is vertical.

[0104] The blades 10 rotate freely around their respective axis of rotation U, articulation pivots 9 of the blades engaging in the bearings carried by the arms 7 and 8 of the frame 4.

[0105] The arm assemblies 7 and 8 extend radially around the central hub. The radius of the frame is represented by R and the diameter of the rotor by D.

[0106] The angular movement of each blade 10 is limited to an angle less than 225° by two internal stops 11 and by two respective peripheral stops 12. The pair of internal stops 11 is arranged symmetrically along a transverse plane, one of the stops being located on the upper part 7 of the frame 4 and the other on the lower part 8 of the frame. The pair of peripheral stops 12 is arranged similarly.

[0107] The internal stops 11 are located at a distance did from the axis of rotation Z of the hub 3, and the peripheral stops 12 at a distance d2 greater than di

[0108] The blades 10 have, for example, in cross-section a thickness ei which decreases from a certain distance away from their geometric axis of rotation U. Near the free end of the blades, the upstream face 14 of the blades ends in a bevel 13, extending for example about one-fifth of the blade length.

[0109] The blades 10 have overhangs 15, of width 15, protruding radially from the frame 4 when the blade is in the working position. The overhang 15 comes to bear against the stops 12 when the blade is in its maximum travel position.

[0110] Each blade 10 has recesses 16 substantially matching the shape of the stops 12, and in which said stops engage when the blade is in the working position.

[0111] The operation of the hydro turbine will now be described with reference to Figures 2 to 7.

[0112] In [Fig.3] we observe two blades 17 and 18 feathered under the effect of the current whose direction is represented by Fi. F2 indicates the direction of rotation of the assembly of blades 10 and of the frame 4. The blades 19 and 20 are in the working position, aligned under the arm assembly 7. The current exerts a thrust on the blades 19 and 20, generating a torque which sets the rotor 2 in rotation, which drives the electricity generator 6. We say that the blades 19 and 20 are thus “in thrust”.

[0113] In [Fig.2] a), the blades 21 and 22 are in the feather position and the blades 23 and 24 are in the working and thrust position.

[0114] In [Fig.2] b), the blade 21 is in the feather position, the blade 22 is in the working position and is pressed against the internal stops 11, the blade 23 is in the working position and in thrust and the blade 24 is in the working position but is not in thrust, it is in a neutral position.

[0115] In [Fig.2] c), the blade 21 is in the feather position, the blades 22 and 23 are in the working and thrust position and the blade 24 comes away from its internal stops 11 and begins to pivot.

[0116] In [Fig.2] d), the blade 21 is in the feather position, the blades 22 and 23 are in the working and thrust position and the blade 24 pivots to feather.

[0117] [Fig.4] explains the operation of the hydro turbine 1 when the direction of the current reverses, a phenomenon symbolized by R2.

[0118] In [Fig.4] a), the direction of the current is represented by Fp. The blades 21 and 24 are in the feather position and the blades 22 and 23 are in the working and thrust position.

[0119] In [Fig.4] b), the direction of the current has reversed and is indicated by F2. The blades 21 and 24 are locked in their position of maximum travel, the current exerts a thrust on the blades, which generates a torque which sets the entire rotor in rotation until all the blades are properly oriented. The blades 22 and 23 are feathered.

[0120] [Fig.5] more precisely reproduces [Fig.4] b). It shows the blades 21 and 24 in their position of maximum travel, their respective overhang 15 coming to bear against the peripheral stops 12. The overhang 15 has a shoulder 25 which matches the shape of said stops 12.

[0121] Figure 6 compares two situations where the thickness eb of the peripheral stops 12 is different. In Figure 6 a), the thickness of said stops is small and the maximum angular deflection of the blade 24 is slightly greater than 180°. In Figure 6 b, the thickness of the stops 12 is greater and the maximum angular deflection is slightly less than 180°.

[0122] [Fig.7] represents the hydro turbine 1 immersed in an aquatic environment, its base 5 being buried in the ground S. A submerged cable 34 for transporting electrical energy is laid on the ground and connected to the generator 6.

[0123] In [Fig.8], the frame 4 of the hydro turbine 1 comprises two reinforcement structures 35 respectively connecting together the arms of each of the assemblies 7 and 8. The hydro turbine 1 comprises a protective gantry 36 encompassing the entire frame 4 and in particular the reinforcement structures 35 of the frame. The gantry connects by a set of cross-shaped arms the upper end of the hub 3 to the base 5 of the hydro turbine.

[0124] The invention is not limited to the illustrated example.

[0125] The number, dimensions and positioning of the stops in the different embodiments may vary to achieve a determined maximum angular movement.

[0126] The frame may also have a different structure. It may comprise two discs connected by vertical uprights arranged on the circumference of the discs and around which blades are articulated. It may have any shape that promotes rigidity, weight and hydrodynamics.

[0127] The blades may have a non-rectangular shape, may be flat or have worked profiles, in particular a shape presenting a curvature like an airplane wing, in particular with rounded corners.

Claims

Claims

1. A hydro turbine (1), intended to be immersed in an aquatic environment animated by at least one current, comprising a rotor (2) with a vertical axis of rotation (Z), the rotor (2) comprising: - a central hub (3) oriented vertically, - a frame (4) rotating with the hub (3), - a plurality of blades (10) articulated on the frame, each pivotally mounted on the frame around a respective vertical geometric axis of rotation (U) with limited angular movement relative to the frame, between a working position where the angle is zero and a position of maximum movement where the angle is less than or equal to 225°, the frame comprising at least two stops (11, 12) to limit the angular movement of each blade (10) relative to the frame, the angular movement of each blade (10) relative to the frame being limited by at least one internal stop (11) and by at least one peripheral stop (12),the hydro turbine being characterized in that each blade (10) has for each respective peripheral stop (12) a corresponding recess (16) in which the stop engages when the blade is in the working position, so that the blade (10) can be substantially aligned between its geometric axis of rotation (U) and the axis of rotation (Z) of the rotor.,

2. Hydro turbine (1) according to the preceding claim, the blades (10) rotating freely around their articulations.

3. Hydro turbine (1) according to one of the preceding claims, each blade (10) having an overhang (15) arranged to come into contact with at least one respective peripheral stop (12) when the blade (10) is in a position of maximum travel.

4. Hydro turbine (1) according to the preceding claim, the overhang (15) having a shoulder (25) bearing on the peripheral stop(s) when the blade (10) is in a position of maximum travel.

5. Hydro turbine (1) according to any one of the preceding claims, the section of each blade (10) having in cross section at least from a certain distance from its axis of rotation (U), a thickness (ej) which decreases as it moves away from the axis of rotation (U).

6. A hydro turbine (1) according to any one of the preceding claims, each blade (10) having a profile, in particular near its free end, tending to promote the creation of a torque causing the blade to pivot out of the working position while the chassis rotates.

7. Hydro turbine (1) according to the preceding claim, the profile having the shape of a bevel (13) present on the upstream face (14) of the blade, preferably extending over a fifth of the length of the blade.

8. Hydro turbine (1) according to any one of the preceding claims, the chassis (4) having two sets of arms, in particular in the form of a cross (7, 8) extending from the hub (3).

9. Hydro turbine (1) according to the preceding claim, the frame (4) comprising at least one reinforcing structure (35), arranged to connect together several arms (7, 8) extending from the hub (3).

10. A hydro turbine (1) according to any one of the preceding claims, comprising a gantry (36), arranged so as to encompass the chassis (4) by connecting the upper end of the hub (3) to a base (5) of the hydro turbine.

11. A method of producing electricity by a hydro turbine (1) according to any one of the preceding claims, in which the rotor rotates an electricity generator (6).

12. Hydro turbine (1) according to any one of claims 1 to 10, the rotor having several stages of blades, the axes of rotation of the blades of the different stages being preferably angularly offset from one stage to another.

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