Patent ID: 12221949

With reference to the aforementioned Figures, a Kaplan-type turbine according to the invention is indicated as a whole with the number10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This turbine10comprises a stator part11and a rotor part12.

The stator part11comprises:a conduit13, schematically shown with a dotted line inFIG.1, configured to convey a flow of water towards an impeller14having a rotation axis X1; said rotation axis X1can be substantially vertical, or have another inclination;a stator15of an electric generator.

The rotor part12comprises:an impeller14, having in turn:an ogive16with at least three blades, for example but not exclusively three blades17, each blade17being of the type with variable angular setup with respect to an inclination axis X2, where said inclination axis X2, clearly visible inFIG.3, is substantially orthogonal to said rotation axis X1;a rotation shaft18bearing the impeller14;adjustment means19for adjusting the setup of the blades17, defined within said ogive16and said rotation shaft18;a rotor20of the electric generator, fixed to the rotation shaft18at said stator15, as schematically shown inFIG.1.

The peculiarity of the Kaplan-type turbine10according to the invention lies in the fact that the adjustment means19for adjusting the setup of the blade17comprise for each blade17:a load-bearing disc21, from which a blade17develops, which load-bearing disc21is constrained to rotate on the ogive16around said inclination axis X2, as clearly visible inFIG.3;a lever23, fixed to said load-bearing disc21and developing inside the ogive16; in particular, the lever23develops radially with respect to the inclination axis X2;a manoeuvring rod24, pivoted at a first end24ato said lever23and at a second opposite end24bto a drive slider25.

The means19for adjusting the setup of said blades17also comprise, within said ogive16:a drive slider25, already mentioned above, to which the second ends24bof said manoeuvring rods24are pivoted;an axial translation system26for said drive slider25, where said axial translation system26is of the type with a nut27and worm screw28; the nut27is fixed to the drive slider25and the worm screw28is fixed coaxially to a drive shaft29positioned to operate inside said rotation shaft18.

The means19for adjusting the setup of said blades17also comprise a pneumatic rotation actuator30for the drive shaft29.

The pneumatic rotation actuator30comprises:a pneumatic motor31mounted on board the rotation shaft18and configured to rotate the drive shaft29with respect to said rotation shaft18;a pneumatic rotating joint32, comprising an external stator body33, clearly visible inFIG.9, fixed to a fixed support structure, and an internal rotating body34configured for the transmission of compressed air to and from said pneumatic motor31.

The rotation shaft18is internally hollow.

The drive shaft29is coaxial to the rotation shaft18.

The drive shaft29passes through the rotation shaft18coaxially thereto.

The worm screw28is, for example and not exclusively, a recirculating ball screw.

The ogive16comprises an internally hollow bulb-shaped body37, bearing a central collar38, coaxial to the rotation shaft18.

The ogive16comprises a bottom39, which is fixed to the bulb-shaped body37.

The ogive16is rigidly connected to the rotation shaft18through a hub40.

The drive shaft29is connected at a first end to the pneumatic motor31and at the opposite second end to the worm screw28.

The drive shaft29is connected to the worm screw28by means of a joint42.

The locking of the joint42to the worm screw28is preferably carried out with a ‘super-bolt’ type clamping and tensioning system.

At the joint42there is also a support with bearings43for the worm screw28.

The worm screw28passes through the central collar38.

The worm screw28passes through the central collar38without coming into contact with it.

The worm screw28is rotatably constrained to the bottom39by a friction-reducing component, for example a bushing45.

The central collar38defines with the bulb-shaped body37an interspace in which the levers23are housed with the respective manoeuvring rods24.

In the embodiment described herein, by way of non-limiting example of the invention, each lever23is supported by a pin22which is fixed to the disc21; still by way of example, each pin22forms a single body with the respective disc21.

The central collar38develops cantilevered inside the bulb-shaped body37.

Between the free end38aof the central collar38and the bottom39there is defined a movement space for the slider25and for the nut27fixed to it.

Each of the discs21rotates in a corresponding seat defined on the bulb-shaped body37by interposition of a bushing44or another similar and technically equivalent friction-reducing component.

As mentioned above, and as visible inFIG.3, each of the discs21comprises a radial pin22that develops from the disc21itself until it rests on a counter-shaped hole51defined on the central collar38.

The radial pin22supports the lever23.

The lever23comprises a fixing base23afor fixing to the disc21and a head23bfor hinging to the manoeuvring rod24.

The manoeuvring rod24comprises, for example, two symmetrical bars defining a fork hinged on one side to the lever23and on the opposite side to the slider25.

For example, the slider25consists of a disc-shaped body.

As visible inFIGS.6and7, the slider25comprises eyelets55configured to be hinged each to a corresponding end24bof a manoeuvring rod24.

The nut27is of the recirculating ball type.

The slider25is free to translate between an upper end-of-stroke setup, well exemplified inFIGS.3,4and7, and a lower end-of-stroke setup, exemplified inFIG.6.

An upper end-of-stroke element46, which defines the upper end-of-stroke setup, and a lower end-of-stroke element47, which defines the lower end-of-stroke setup are therefore defined within the ogive16.

Preferably, the upper end-of-stroke element46and the lower end-of-stroke element47are configured and positioned so as to meet the slider25.

In the present non-limiting embodiment of the invention, the upper end-of-stroke element46consists of an annular body fixed to the slider25and configured to meet the lower edge of the free end38aof the central collar38.

Likewise, by way of example, the lower end-of-stroke element47consists of a disc with one or more rest projections47aconfigured to meet the slider25and not the nut27.

The lower end-of-stroke element47is fixed to the lower end of the worm screw28.

In particular, and by way of example, the lower end-of-stroke element47is fixed to the worm screw28by means of a ‘super-bolt’ type clamping and tensioning system.

The pneumatic rotation actuator30also comprises a tubular support body60integral with and coaxial to the rotation shaft18.

The pneumatic motor31is fixed inside this tubular support body60.

As clearly visible inFIG.9, the internal rotating body34of the pneumatic rotating joint32is fixed to a cover61of the tubular support body60, so as to rotate coaxially to the rotation shaft18.

The internal rotating body34is fixed to the outside of the tubular support body60.

The cover61has two through channels62and63for compressed air, a first channel62and a second channel63.

These first62and second63channels are connected with respective inlet/outlet conduits62aand63adefined on the internal rotating body34of the pneumatic rotating joint32.

These first62and second63channels are connected with a corresponding inlet fitting64and a corresponding outlet fitting65of the pneumatic motor31.

The first62and second63channels operate alternately one as an outward channel and the other as a return channel, and vice versa.

The external stator body33of the pneumatic rotating joint32is supported by a fixed, i.e., stationary, structural element not illustrated for simplicity's sake.

The pneumatic rotating joint32is in turn connected to an air compressor, which is obviously to be intended of a known type.

This air compressor is configured, for example, to circulate through the pneumatic rotating joint32air at a pressure of 6 bar.

The Kaplan-type turbine10according to the invention also comprises detection means70for detecting the angular position of the blades17.

In the embodiment described herein of the invention, which is exemplary and non-limiting of the invention itself, the detection means70comprise:a movable body80;displacement means81configured to displace said movable body80in a manner proportional to the rotation angle of said blades17;a sensor82configured to detect the displacement of said movable body80.

For example, the movable body80comprises an annular body80aplaced to surround the tubular support body60.

The annular body80ais constrained to one or more rotatable threaded stems83whose rotation causes the same annular body80ato displace in a first direction or in a second opposite direction in the direction of the rotation axis X1.

Each of said rotatable threaded stems83is placed to rotate in a threaded bushing84fixed to the annular body80a.

Each of the threaded stems83is placed to rotate with its main axis being parallel to the rotation axis X1.

Each of the threaded stems83has a driven toothed wheel85.

Each driven toothed wheel85is meshed with a drive toothed wheel86integral with the drive shaft29, i.e., fixed to the drive shaft29.

The threaded stems83are supported by a support structure87fixed to the rotation shaft18.

In particular, in the present embodiment, the support structure87comprises a base disc88, fixed to the upper end of the rotation shaft18, and an annular cover89to which the threaded stems83are rotatably constrained.

Each of the threaded stems83is rotatably constrained to the annular cover89by a corresponding bushing90, clearly visible inFIG.8.

The tubular support body60is fixed to the annular cover89.

The pneumatic motor31is also fixed to the annular cover89.

The rotating shaft31aof the pneumatic motor31is fixed to the drive shaft29by means of a transmission sleeve91, as clearly visible inFIG.8.

The drive toothed wheel86is fixed, obviously coaxially, to the transmission sleeve91.

The sensor82is, for example, an infrared sensor.

This sensor82is fixed to a fixed structural part95of the turbine10or of the compartment containing the turbine10.

The sensor82faces the annular body80a.

In particular, the sensor82faces the annular body80ain a direction substantially parallel to the rotation axis X1.

The rotation of the drive shaft29with respect to the rotation shaft18causes the synchronous rotation of the threaded stems83; the rotation of the threaded stems83in turn causes the displacement in the direction of the rotation axis X1of the annular body80a, either towards the sensor82or away from the sensor82.

This displacement of the annular body80ais detected by the sensor82and, through an electronic control unit, is transformed into a value of the inclination of the blades17.

The position of the annular body80awith respect to the sensor82is therefore proportional to the inclination angle of the blades17with respect to a predetermined angular reference.

The operation of the adjustment means19for adjusting the angular setup of the blades17is therefore described below.

If it is wished to change the setup of the blades17, the external compressor is activated so that a pressurised air flow, for example at 6 bar, enters the pneumatic motor31through the pneumatic rotating joint32.

The pneumatic motor31has a stator portion fixed to the tubular support body60, in turn fixed to the rotation shaft18bearing the impeller14, and a rotating shaft31afixed to the drive shaft29.

The pneumatic motor31then induces the rotation of the drive shaft29in one rotation direction or in the opposite direction.

The rotation of the drive shaft29, depending on the rotation direction, causes the translation of the nut27and hence of the slider25fixed to it or the lowering, i.e., towards the bottom39of the ogive16, or the lifting, i.e., in the opposite direction.

The translation of the slider25in turn causes an action on the levers23of the blades17through the respective rods24.

For example, inFIG.6it is exemplified that lowering the slider25results in a traction on the lever23downwards through the rod24and a consequent rotation in a first rotation direction, for example counterclockwise, of the disc21to which the blade17is fixed.

InFIG.7it is exemplified that lifting the slider25results in a thrust on the lever23upwards through the rod24and a consequent rotation in a second rotation direction, for example clockwise, of the disc21to which the blade17is fixed.

The translation of the slider25takes place, as mentioned above, between two end-of-stroke setups, one upper and one lower, each of which defines an angular limit position of each blade17beyond which the blade17cannot rotate with respect to its inclination axis X2.

The rotation shaft18is supported by at least two bearings96aand96bat the ends thereof, which bearings are in turn constrained to corresponding fixed radial supports97and98.

Practically, it has been established that the invention achieves the intended task and objects.

In particular, with the invention a Kaplan-type turbine has been developed that allows to eliminate the risk of environmental contaminations due to oil leaks from the turbine itself, thanks to means for adjusting the angular setup of the blades that work without any use of oil or other liquid.

In addition, with the invention a Kaplan-type turbine has been developed with no less robustness and efficiency than similar Kaplan turbines of known type.

The invention thus conceived is susceptible to many modifications and variants, all falling within the same inventive concept; furthermore, all details can be replaced by other equivalent technical elements.

In practice, the components and materials used, as well as the dimensions and contingent shapes, as long as they are compatible with the specific use, can be any according to requirements and the state of the art.

Where the features and techniques mentioned in any claim are followed by reference marks, such reference marks are intended to be affixed solely for the purpose of increasing the intelligibility of the claims and, consequently, such reference marks have no limiting effect on the interpretation of each element identified by way of example by such reference marks.