Easily manufactured, transportable and installable hydroelectric production unit
The Archimedes screw turbine's modular design with dowels and dynamic seals addresses manufacturing, transport, and installation challenges, enhancing efficiency and reducing leaks and vibrations in hydroelectric systems.
Patent Information
- Application Number
- FR2023010747
- Authority / Receiving Office
- FR · FR
- Patent Type
- Utility models
- Current Assignee / Owner
- Filing Date
- 2023-10-07
- Publication Date
- 2025-10-17
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing hydroelectric production systems are cumbersome to manufacture, transport, and install, and they lack efficient assembly methods that ensure precise alignment and sealing to minimize leaks and vibrations.
The Archimedes screw turbine is designed with modular components such as slats and blades that can be easily assembled using dowels, pins, or mortise-tenon joints, and incorporates dynamic seals to minimize leaks, while the assembly sequence ensures precise alignment and vibration dampening through a cradle and turbine frame.
Facilitates easy manufacturing, transport, and installation of hydroelectric units with improved sealing and reduced vibrations, ensuring efficient energy conversion and reduced acoustic nuisance.
Smart Images
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Abstract
Description
Title of the invention: Easily manufactured, transportable and installable hydroelectric production unit Details of the invention
[0001] The Archimedes screw turbine (not shown in [Fig.l]) consists of a. a barrel, a cylindrical part, which can be hollow to lighten the assembly. Advantageously, this barrel is made up of assembled wooden elements of great length in relation to their section, called "slats". The section may be trapezoidal, with two converging faces, and two others straight or curved, the angle of the converging faces being defined according to the number of elements constituting the barrel in order to produce a complete hollow cylinder. Assembly elements such as dowels or pins, positioned on the converging faces, may be used to assemble these elements together. In another embodiment, other assembly elements are used (lamello for example for wood), or complementary shapes used to assemble and position the parts (mortise-tenon joints). Grooves arranged on the external faces may allow metal strapping bands to be positioned along the barrel to keep it assembled. b. Threads of the Archimedes screw, surfaces extending axially along the generatrix of the screw shaft from one end to the other or over a portion thereof, delimited by two helical turns, one included in the outer surface of the shaft which will be called the inner diameter of the thread, the other in a cylinder called the outer diameter, with a diameter generally close to twice the inner diameter. The Archimedes screw comprises a whole number of threads (generally 3 or 4) distributed uniformly around its axis. In the invention which is the subject of the present invention application, the threads are made up of unitary elements called blades. The assembly of these unitary elements of thickness on the shaft makes it possible to reconstitute a complete thread. These independent elements can follow a perfect shape of a portion of the thread, or an approximation in order to facilitate their production.On the other hand, they have an interface at their base allowing them to be assembled with the barrel. Various means are used to assemble the threads on the barrel. In one embodiment, the blades are installed on the slats in grooves provided on the latter for this purpose, via assembly elements such as screws going from the inside to the outside of the barrel, before assembly of the latter. In . In other embodiments, mortise and tenon joints are made to hold the blades on the slats of the shaft. The interfaces between the blades are called converging faces. In one embodiment, they are parallel and in contact during operation. In other embodiments, elements are added to improve the mechanical strength of the assembly or the sealing between the blades. In other embodiments, a sealing element such as a gasket is added to prevent water leaks between the blades. The shape of the converging faces can also be adapted to add connecting or sealing elements between the blades. In particular, mention may be made of the machining of complementary shapes allowing the integration of trunnions or other assembly or sealing elements. Grooves may also be provided opposite each other to integrate assembly elements between the blades. In another embodiment, staples are added between the blades. In other embodiments, elements such as metal strips, arranged in a helical manner along the threads, make it possible to connect the different blades together. c. In another assembly method, slats, called plates, incorporating several blades are added over the slats of the barrel. The blades can be fixed to the plates by the means described previously. The plates can be fixed to the barrel by any means, such as for example by screws fixed from the outside to the inside of the cylinder. These intermediate elements make it easier to replace damaged blades, their fixing elements being accessible without completely dismantling the assembled barrel. d. Bearings, allowing the fixed part and the rotating part to be decoupled, in particular an upper bearing and a lower bearing, the turbine being installed at a declination angle, generally close to 30°. In one embodiment, the upper bearing is a standard commercial bearing, comprising a ball bearing, capable of accepting slight swiveling, and also comprising an axial stop such as a pressure screw, allowing the turbine to be stopped axially. In the same embodiment, the lower bearing does not have an axial stop, and may be made of plain bearings, in particular made of corrosion-resistant materials. The lower bearing may be protected by being integrated into a sleeve made of corrosion-resistant materials. Sealing elements such as brushes will limit pollution of the bearing by abrasive elements such as sediments.Dynamic sealing elements, via pressurized water, will potentially limit pollution by particles. In a mode of . embodiment, the height difference of the waterfall where the turbine is installed is used to create a static pressure, and a water intake is arranged to inject pressurized water into the lower bearing. This water can be filtered to ensure its cleanliness. In another embodiment, the pressure of the clean water protecting the bearing is obtained by a pump driven in rotation by the turbine. In one embodiment, the lower bearing constitutes the axial thrust and the upper bearing only absorbs radial forces. e. Interface elements between the turbine and the bearings, most often metal elements. In one embodiment, they are made up on each of the two faces of the barrel (front and rear) of an interface plate comprising a centering means on the barrel and assembly elements, axes held by the bearings, and intermediate parts providing the connection between axes and plates. One of the aforementioned elements generally makes it possible to fix a transmission element such as a toothed wheel, making it possible to transmit the mechanical power of the turbine to other mechanical transmission elements or to an electric generator, via elements such as chains, belts or sprockets. In certain embodiments, an internal tube extending along the axis of rotation of the turbine makes it possible to pre-align the metal axes of the bearings during assembly thereof (see paragraph concerning the assembly sequence).
[0002] In one embodiment, the machining of the wooden elements is carried out on elements saturated with humidity, the increase in the relative humidity of the wood no longer significantly modifying its geometric stability.
[0003] The trough (shown in yellow in [Fig.l] in an exemplary embodiment) is made up of: a. of independent slats, pieces of great length in relation to their section and of trapezoidal section. The slats are in contact on their lateral faces (the inclined faces of the trapezoid). These faces can be flat, slightly curved or curved, and possibly provided with sealing joints or interface elements (grooves-mortises, groove + "lamello"...). The large base of the trapezoid is flat, the small base is a portion of a circle, allowing a cylindrical interior surface to be formed after assembly of the slats. The inner diameter of this cylinder then corresponds to the outer diameter of the threads of the Archimedes screw turbine, as well as a functional clearance allowing the turbine to turn inside without untimely contacts, which could occur due to alignment defects, manufacturing defects, or deformations of the assembly. The slats are provided at the end with interface zones with parts called "formers". These interfaces allow to interface with a groove, and can be machined surfaces of cylindrical shape, pins (typically two per slat) or even lobes, two in number. The slats are also provided on the large base with grooves allowing the positioning of hoops whose function is to hold the assembly in position. In certain embodiments, the trough does not form a closed cylinder, it is perforated in particular to allow physical and visual access to the turbine. The operation of the Archimedes screw turbine allows for perforating on approximately 1 / 3 of the upper part of the trough. Hoops are used to replace the absence of slats in these areas and allow the compression of the trough by the hoops. These hoops can be of various types, either portions of slats provided with interface pieces between them and with the rest of the trough, or hoops that can be specially made for this function.A single piece may also be provided to connect the various hoops. In the case where hoops are used to open the slat, their minimum number corresponds to the number of hoops necessary to ensure the maintenance of the trough. The hoops have a groove allowing the passage of the hooping strip. Furthermore, in other embodiments, the openwork parts can be closed by removable or movable covers, making it possible to limit the acoustic nuisance of the turbine in operation, in particular by the addition of materials or devices promoting acoustic attenuation. b. Shapers (in purple (resp blue) for the upstream (resp downstream) shaper in [Fig.l], in an exemplary embodiment, mentioned previously, at each end of the trough. These parts have the function of mechanically interfacing the slats with the structure of the electrical production unit, of maintaining a perfectly cylindrical shape of the trough, and designed to facilitate its assembly. The shapers form a groove that can be obtained by assembling independent parts. In particular, the outer part of the groove can be obtained by assembling on a structure trapezoidal parts of depth close to the desired groove. The small base of these trapezoidal parts is a portion of a circle.The assembly of these parts forms a perfect inner circle on which is added a rolled metal sheet extending axially beyond the trapezoidal parts, thus forming a cylinder of diameter equal to the internal diameter of the trough, on which the slats of the trough are tightened when they are strapped. On the other hand, the outer part of the groove can be obtained by one or more other parts being fixed on the plate. The outer diameter. groove obtained using these parts is slightly larger than the outer diameter of the interfaces machined at the end of the trough slats. The main function of this outer portion of groove is to facilitate assembly of the trough, in particular to retain the slats in the lower part when construction begins. It is potentially removed after assembly.
[0004] It is envisaged to use a dynamic seal to limit or eliminate leaks occurring in the clearance between the trough and the turbine. In one embodiment, a ring provided with a section of material extending circumferentially at 360 degrees is fixed on the outside diameter of the turbine. The slats of the trough are provided with a 360° groove, complete or partial, which can be closed by an added part, in which the previously described ring of material rotates, constituting a "labyrinth" type obstacle to the flow of water between the turbine and the trough. In other embodiments, the groove and the ring of material can be reversed. In other embodiments, a seal having friction surfaces between rotating parts and fixed part can be used, with the disadvantage of introducing additional losses into the installation.
[0005] The structure is adapted according to the requirements of the site on which the turbine is installed. It is generally made up of: a. A cradle (in garnet on [Fig.2] in an example of realization) consisting of one or more vertical frames, connected together by crosspieces, arranged in such a way as to ensure optimal absorption of forces, and maintenance of the geometry of the structure. This assembly is connected to different anchor points, which can be located on civil engineering elements such as concrete blocks, walls, ceilings or even anchors positioned in rocks naturally present on the site. Flexible elements such as anti-vibration stops can be installed in order to dampen the vibrations of the structure induced by the turbine in particular. b. A turbine frame, installed at an angle of approximately 30° to the horizontal (in pink in [Fig.l] in an example of an embodiment), but which may vary depending on the installation, supporting the bearings, the turbine and the trough, and connected to the rest of the structure by vertical and axial stops (along the axis of the turbine), fixed to the rest of the structure via assembly elements (screws, flanges, etc.). The lower part of the turbine frame may be directly in interface with the ground or the civil engineering elements. The turbine frame supports the upper bearing and the lower bearing, as well as mechanical transmission elements and possibly the electrical generator. The lower bearing support may be removable. The turbine frame also supports the trough and its conformers. In certain modes embodiment, the turbine frame includes adjustment means for adjusting the alignment of the center of the upper former with respect to the axis of rotation of the turbine. In some embodiments, the lower bearing support is fixed to the lower former of the trough to ensure perfect concentricity of the trough with respect to the rotating part. The methods of assembling the upper and lower bearings include clearances allowing their alignment before fixing their position. In some designs, flexible elements such as anti-vibration stops are integrated in order to decouple the vibrations induced by the turbine from the rest of the structure.
[0006] Assembly sequence: a. civil engineering is carried out if necessary, with positioning of anchor points b. the cradle is manufactured and installed on the civil engineering c. the turbine frame is installed on the cradle d. the bearings are aligned using tools to ensure the coaxiality of the two metal turbine shafts, then they are fixed in position; the metal interface parts are fixed to the shafts held by the bearings? e. the turbine shaft is assembled directly onto the metal parts, which have interfaces provided for this purpose, ensuring the possibility of individually holding the shaft slats without them falling even before the strapping and retaining screws are installed, which allows a reduced number of people to carry out this operation. Assembly tools are possibly used for this purpose. f. the turbine blades are installed on the shaft g. The trough is assembled on the formers held by the turbine frame. To do this, the outer part of the formers is installed, allowing the lower slats to be held in the groove, with a certain amount of play. The slats are then inserted one by one into the groove thus formed. Once all the slats are in place, the strapping allows the slats to be tightened onto the inner part of the formers.
[0007] The easements of the hydroelectric production unit consist in particular of: a. a supply channel, which may be an excavated natural channel, a channel masonry or an open-air conduit of different technologies. In some embodiments, the final part of the supply channel consists of a wooden conduit, supported by structural frames connected to the ground via civil engineering works or installed on anchor points. In some embodiments, the channel consists of a central trapezoidal batten, two planks constituting the bottom of the channel, and two side boards, the assembly being held in compression by side screws. Sealing elements such as braided gaskets are held in compression by the pressure of the assembly screws. The inlet channel is provided with a protective grid and possibly equipped with a pilot-operated valve allowing the regulation of the water level in the turbine b. a tailrace, possibly partially made of a pipe which may be made of wood, and equipped with a controlled valve to regulate the water level at the turbine outlet. The interface between the trough and the tailrace is optimized in shape to ensure a harmonious flow at the turbine outlet and limit the acoustic level. The tailrace is possibly partially streamlined and equipped with elements promoting acoustic attenuation.
Claims
Claims
1. Hydroelectric production unit, consisting mainly of an Archimedes screw turbine, a trough and a structure, designed to be disassembled into manipulable sub-elements, allowing its assembly in a “kit” directly on its final operating site.
2. Hydroelectric production unit according to the preceding claim, characterized in that it comprises an Archimedes screw turbine with a barrel made up of assembled elements, and whose threads are also made up of sub-elements making it possible to form perfect or approximate turns, possibly assembled on the barrel via intermediate elements allowing easy replacement of the sub-elements.
3. Hydroelectric production unit according to one of the preceding claims, characterized in that it comprises a trough made up of assembled sub-elements, including slats and shapers, ensuring the structural strength of the trough assembly and high precision of the internal diameter thereof.
4. Hydroelectric production unit according to one of the preceding claims, characterized in that it comprises a sealing device between the turbine and the trough, of the labyrinth seal type making it possible to limit leaks between them.
5. Hydroelectric production unit according to claim 3, characterized in that it comprises a device for adjusting the alignment of the bearings and the position of the trough shapers, making it possible to limit coaxiality defects of the turbine and the trough.
6. Hydroelectric production unit according to one of the preceding claims, characterized in that it comprises acoustic attenuation devices arranged on the trough of the Archimedes screw turbine.
7. Hydroelectric production unit according to one of the preceding claims, characterized in that it comprises a lower bearing consisting of plain bearings and silt protection devices such as dynamic seals or a hydrostatic pressure sealing device.