CH707299B1 - Hydroelectric unit used for generating electricity from the flow of a waterway comprises a water wheel with support and float for maintaining the water wheel immersed during operation - Google Patents

Abstract

Hydroelectric unit (1) comprises at least one water wheel (2), at least one electricity generator (16) driven by the water wheel and a water-wheel support (4) connectable to a fixed structure in a pivoting manner. The support is sized and configured to maintain the water wheel at least partially immersed in the waterway during operation. The unit comprises at least one float (9) connected to the support which is positioned below the water wheel. An adjustment mechanism (13) controls the vertical distance between the float and the water wheel. An independent claim is included for a hydroelectric power plant generating electricity from the flow of a waterway.

Description

Field of application

[0001] The invention relates to the field of machines for generating energy from hydroelectric sources, in particular a hydroelectric unit according to claim 1 and a plant according to claim 9.

Known art

[0002] Hydroelectric energy is a renewable source, without any emission into the atmosphere and very interesting from an environmental point of view. Several hydroelectric plant solutions are known which differ according to the height difference and the available water flow.

[0003] Installations designed for large gradients (hundreds of meters) are only possible in some geographical areas where a high-altitude basin can be available, for example in mountain locations. Currently, especially in Europe, this type of resource has been exploited almost to its maximum capacity and it is difficult to find sites to install new plants at convenient conditions. Sometimes the construction of a dam is necessary, which makes the investment convenient only for large plants and has a significant environmental and landscape impact.

[0004] Plants are also known that are designed to take advantage of large flows with relatively modest drops of just a few meters, which may be available by intercepting a watercourse. However, these plants have some disadvantages. They require impressive works to block the water course, which have a high cost and have an environmental impact on the river ecosystem, because they hinder their natural course. Because of the high costs, plants of this type are normally realized only for medium-large installed powers and on the major waterways.

[0005] For these reasons, with the techniques available today it is difficult to increase the share of energy from a hydroelectric resource. It is difficult to find a site suitable for the construction of a hydroelectric plant and capable of producing significant amounts of energy.

[0006] The applicant has realized that a large amount of energy would be available by exploiting the natural stream of rivers such as rivers and streams, but this energy is not exploited. On the contrary, it is daily dissipated because the current technique does not provide a simple and efficient solution to collect it and convert it into electricity.

[0007] In the GB 1 518 268 patent, a floating wheel made of plastic and internally hollow material was proposed, supported by a pivoting arm hinged to a structure that crosses a stream. This floating wheel, equipped with a suitable blading, should be able to convert the current of a stream of water into electricity. A floating wheel generator with similar characteristics is also disclosed in US 6 616 403.

[0008] However, these solutions have not found practical applications due to some disadvantages.

[0009] The floating wheel proposed in these previous patents, in fact, would be very sensitive to variations in water flow and currents because its position is determined by buoyancy and because the wheel itself must be very light and therefore with low inertia, which would make the operation inconsistent. Moreover, the major disadvantage is that in conditions of low water flow (ie "dry") the wheel would touch the river bed irreparably damaging. This last problem is particularly limiting for plants intended for rivers that are known to be subject to continuous changes in the water level and may remain dry in the event of drought. Said pivoting wheel systems, therefore, despite having been proposed in the patent literature, have never found a concrete application until now.

Summary of the invention

[0010] The object of the present invention is to improve the prior art discussed so far, eliminating the disadvantages. The main purpose of the invention is to make available a technique capable of conveniently exploiting the energy of the currents of the water courses, which is currently dispersed. In particular, an object of the invention is to provide a hydroelectric group with a pivoting wheel suspended on a waterway, able to adapt to changes in the level of the waterway, without risk of damage and with the possibility of producing energy even with a very low water level.

[0011] These objects are achieved with a hydroelectric unit according to the annexed claim 1 and the claims dependent on it. Said hydroelectric group allows the generation of energy from the current of a watercourse, and comprises at least one water wheel and at least one electric power generator driven by said water wheel. Said wheel has a pivotable support connectable to a fixed structure, such as for example a bridge, as will be better described below. Said support is sized and configured to keep said water wheel at least partially immersed in said water course during operation, said wheel being thus set in rotation by the effect of the water stream. The hydroelectric unit is also characterized in that it comprises at least one float also connected to said support of said water wheel, and in that said float is positioned below said water wheel, and said group comprises an adjustment mechanism of a vertical center-to-center distance between said float and said water wheel.

[0012] Said wheelbase is defined in a vertical plane, for example between the axis of rotation of the water wheel and a longitudinal or barycentric axis of the float. In some preferred embodiments, there is a plurality of floats and said floats are at the sides of said wheel.

[0013] A preferred embodiment of said pivoting support provides at least a first arm carrying said water wheel and a second arm carrying said at least one float, i.e. one or more floats. A plurality of floats can be arranged for example symmetrically on the sides of the wheel.

[0014] More preferably, said first arm and said second arm have a common hinge anchoring point with respect to said fixed structure, and the hydroelectric unit comprises a device for adjusting the mutual position between said first arm and said second arm, and of locking of said position in a desired configuration. For example, in a preferred embodiment, said adjustment device acts by varying the angle formed between said two arms, with vertex in said hinging anchorage point. In a preferred embodiment, the adjustment device comprises a centimeter screw.

[0015] Preferably the arms are U-shaped to support the weight of the wheel and the thrust of the water which acts both on the wheel and on the float (or on the floats, if more than one).

[0016] Also the number of water wheels of a single group can be greater than one, for example two or more wheels side by side.

[0017] The generation of electrical energy takes place with one or more motors driven by the water wheel, or by the hydraulic wheels, with a suitable transmission means such as a toothed belt which engages a pulley integral with the wheel. A preferred embodiment provides a double groove pulley and two belt transmission.

[0018] Said fixed structure can be for example an existing bridge. The use of an existing bridge greatly reduces the installation costs because the system components, for example the water wheel and the two-arm support, can be transported and mounted on site, and it is not necessary to erect a structure of dedicated support.

[0019] The object of the invention is also a hydroelectric installation or plant comprising one or more groups according to the invention. Preferably the system also includes a system of converging bulkheads immersed in the water course, immediately upstream of the group (or groups), to direct the water towards the wheel or wheels.

[0020] Advantageously, the plant also includes a barrier upstream of the plant for intercepting solid bodies, such as for example a network with meshes of suitable width.

[0021] A hydroelectric plant according to the invention can comprise a plurality of hydroelectric groups of the type described, possibly connected to the same fixed structure, for example a bridge. Groups can be arranged according to various configurations; a particularly preferred configuration is made with three groups, of which one group is located upstream, and is therefore the first to be crossed by the stream of water, and the remaining two groups are located downstream of the first, and on the sides thereof. Advantageously, in this configuration with three groups, as many and respective bulkhead systems and at least a water-splitting bulkhead that distributes the discharge water flow of the first group towards the inlet bulkhead systems of the two downstream groups.

[0022] The main advantage of the invention is that the position of the wheel, with respect to the surface of the water, is controlled by the float. Being positioned under the wheel, the float protects the wheel from impact against the river bed, so that the system works even with little water. For example, if the water level is very low the float rests on the bottom but the wheel can continue to turn even with the little water available.

[0023] The applicant has calculated that even with about 10 cm of water the plant according to the invention is able to function. The applicant has also calculated that water courses with a minimum slope (approx. 1%) can already set in motion a plant according to the invention and therefore can constitute a useful energy resource.

[0024] The fine adjustment, for example with a centimetric screw, makes it possible to adapt the system to the water course conditions and gives installation flexibility.

[0025] Another advantage is that a floating wheel, for example made of plastic or hollow material, as suggested in the known art, is no longer required. The wheel can be made with a traditional technique, for example in steel, and can have a greater mass which makes the rotation more stable.

[0026] It should also be noted that the installation costs are very low and that the environmental impact is almost nil. A hydroelectric plant according to the invention does not require any barrier works such as dams, etc. anchoring to an existing bridge. It should also be emphasized that the disturbing effect on the watercourse and its currents is minimized because the river is not barred; simply extract the energy of the current without changing its natural course and without introducing insurmountable barriers to the fish fauna that damage the ecosystem.

[0027] The invention therefore provides a source of energy that is respectful of the environment. It allows you to increase the share of non-polluting energy from renewable sources, using a resource that is widely available, such as river currents, but which has never been adequately exploited up to now.

[0028] Further advantages and features of the present invention will become apparent from the following description, given by way of non-limiting example, and with the aid of the drawings.

Brief description of the drawings

[0029] <tb> Fig. 1 <SEP> shows schematically the components of a hydroelectric group according to a preferred way of carrying out the invention. <tb> Fig. 2 <SEP> shows the hydroelectric group of Fig. 1, seen from above. <tb> Fig. 3 <SEP> shows a detail of a possible way of carrying out the anchoring of the group of fig. 1 - 2 to a structure such as a bridge. <tb> Fig. 4 <SEP> shows, from above, a plant comprising three hydroelectric groups, according to one of the ways of realizing the invention. <tb> Fig. 5 <SEP> illustrates an example of conveying water in a system of the type illustrated in Fig. 4.

Detailed description

[0030] Fig. 1 shows the main components of a group 1 for the generation of hydroelectric power from a watercourse.

[0031] Said group 1 comprises a water wheel 2 equipped with vanes 3 distributed along its circumference, connected to a fixed structure (not shown in Fig. 1) through a support 4 hinged to a supporting element 5.

[0032] The support 4 is pivoting in the plane of the wheel 2, as indicated by the arrows 6 of fig. 1 It comprises a first arm 7 which carries the wheel 2, and a second arm 8 which carries, at its distal end with respect to said carrier 5, a plurality of floats 9. Said floats 9 are positioned below said wheel 2, and determine the positioning of the wheel 2 itself with respect to the free surface of the water. The free coat is indicated with the reference 10.

[0033] The arms 7 and 8 are preferably configured U-shaped, as best seen in the view from above of Fig. 2, and are made for example from aluminum alloy or light alloy.

[0034] Still with reference to fig. 1, it can be seen that said first arm 7 is substantially rectilinear and that, at the distal end with respect to the supporting element 5, it supports the axis 11 of the wheel 2, for example on ball bearings. The second arm 8 also U-shaped has, in the side view of Fig. 1, a broken profile formed by two rectilinear segments, and ends with the end 12 to which the floats are fixed 9.

[0035] It is also noted from fig. 1 that the arms 7 and 8 have a common hinging anchorage point 30 with respect to the supporting element 5, and that a centimetric screw 13 is provided which allows to precisely adjust the reciprocal position between the arms 7 and 8. By acting on said screw 13 it is possible to modify the angle between the arms 7 and 8 (measured with a vertex at the hinge point 30) and, consequently, also the distance between said wheel 2 and the floats 9, in this case of fig. 1 represented by the vertical wheelbase D between the axis of rotation 11 of said wheel 2 and a longitudinal axis of the floats 9.

[0036] It can be understood, observing fig. 1, that the adjustment carried out with the centimetric screw 13 allows to determine the floating position of the wheel 2 with precision; in addition, during use, and due to the floats 9, the wheel 2 follows the water level 10 maintaining constant operation regardless of the increase or decrease in water level. In the case of low flow ("dry" conditions), the floats 9 can go in support protecting the wheel 2 which continues to function until a little water is available.

[0037] It should be noted in this regard that the vertical interaxis D is such that the distance between floats 9 and periphery of the wheel 2 is greater than the height of the blades 3, so that the rotation of the blades 3 is always possible.

[0038] The blades 3 can be made according to the known technique of the hydraulic wheels. For example in the figure blades are shown which have a concave belly 14 designed to maximize the thrust of the water, for example with a spoon like in the wheels of known type, and a convex back 15 to facilitate entry into the water during rotation. The direction of rotation in fig. 1 is clockwise as indicated by the arrow R.

[0039] The wheel 2 drives one or more electric generators 16 by means of a belt transmission 17 which engages a pulley 18 keyed onto the wheel 2 itself. The belt 17 is preferably a toothed belt gripping a suitable groove in the pulley 18.

[0040] In a preferred embodiment the pulley 18 has a double groove and the transmission comprises two belts 17. In this way it is possible to have electric generators that can be disconnected independently for example for maintenance.

[0041] The characteristics described up to now emerge even more clearly by observing fig. 2, in which the U-shape of the arms 7 and 8 can also be seen, and the symmetrical arrangement, on the sides of the wheel 2, of four floats 9. The flow of the water stream is indicated by the arrow F.

[0042] Fig. 3 shows an example of execution of the pivoting connection of the support 4 to the supporting element 5, by means of two half-flanges 19.

[0043] The supporting element 5 is preferably a part of an existing bridge that overlooks the waterway, so that the group 1 can be installed at a particularly low cost by using a fixed structure already available.

[0044] Fig. 4 shows an arrangement of three groups of the type described above, with anchorage to a bridge P which extends between the two banks S of the watercourse.

[0045] The configuration of fig. 4 provides a first group 1A positioned substantially at the center of the width of the water course and the subsequent two groups 1B, 1C positioned downstream, and at the sides, of the first group 1A.

[0046] The direction of the current is indicated by F. The effluent water from the first group 1A is divided between said two downstream groups. This optimizes the use of water energy. At this point, a person skilled in the art will be able to understand that other configurations, with a greater number of groups, are possible based on the characteristics of the waterway and of the installation site.

[0047] Fig. 5 is a diagram of water conveyance in a configuration with three groups like the one in fig. 4

[0048] A first system of converging bulkheads 20 conveys the water towards the front group 1A, where a part of the water energy is extracted from the respective water wheel. The discharge of the effluent group 1A from the section 21 is directed to the downstream groups by means of a watershed wall 22 and respective bulkheads 23, 24 dedicated to the groups 1B, 1C.

[0049] The bulkhead systems 20, 23, 24 are made with walls advantageously made of reinforced concrete, of suitable thickness and with transverse support bars 25.

[0050] A suitable sizing, by way of example, is the following. The wheel 2 has a diameter of about 3 m and the double-groove pulley 18 has a diameter of 1.7-2 m and the height of the blades 3 is about 40 cm.

[0051] The bulkhead system 20 (and likewise other systems of bulkheads possibly provided, such as for example the systems 23, 24) has reinforced concrete walls having a width equal to 20 cm and height preferably between 0.5 and 2 meters, more preferably between 1 meter and 1.5 meters. The minimum width of the section 21, at the end of the convergent zone, is preferably about 0.5 meters.

Claims (13)

1. Hydroelectric group (1) for power generation from a stream, comprising: at least one water wheel (2) and at least one electric power generator (16) driven by said water wheel; a support (4) of said water wheel, which can be pivotally connected to a fixed structure, said support being sized and configured to maintain said water wheel (2) at least partially immersed in said waterway during operation, said wheel (2) being thus set in rotation by the effect of the water stream, the group being characterized: in that it comprises at least one float (9) also connected to said support (4) of said water wheel (2), and in that said float (9) is positioned below said water wheel (2), and said group comprises an adjustment mechanism (13) of a vertical distance (D) between said float (9) and said water wheel (2). 2. Hydroelectric unit according to claim 1, characterized in that: said pivoting support (4) comprises at least a first arm (7) which carries said water wheel (2) and a second arm (8) which carries said at least one float ( 9). 3. Hydroelectric unit according to claim 2, characterized in that: said first arm (7) and said second arm (8) have a common hinging anchor point (30) with respect to said fixed structure, and the group (1) it includes a device for adjusting the mutual position between said first arm and said second arm, and locking in a desired configuration. 4. Hydroelectric unit according to claim 3, characterized in that said adjustment device acts by varying the angle formed between said first arm (7) and second arm (8) with a vertex in said hinging anchor point (30). 5. Hydroelectric unit according to claim 3 or 4, characterized in that said adjustment device comprises a centimetric screw (13). 6. Hydroelectric unit according to any of the claims from 2 to 5, characterized in that said first arm (7) and said second arm (8) are U-shaped. 7. Hydroelectric unit according to any one of the preceding claims, comprising a plurality of electric generators (16) and comprising a system for transmitting motion from said water wheel to said generators, said transmission system comprising a keyed pulley (18) with a double groove to said water wheel (2), and a double transmission belt (17). 8. Hydroelectric unit according to any one of the preceding claims, comprising a plurality of floats (9) arranged symmetrically with respect to said wheel (2). 9. Hydroelectric plant to generate energy from the current of a watercourse, including: - at least one hydroelectric unit (1) according to any one of the claims from 1 to 8; - a system of bulkheads immersed in the course of water immediately upstream of the said hydroelectric group, and converging towards the said group to direct the water towards it. 10. Hydroelectric plant according to claim 9, also comprising a network barrier that can be installed upstream of the plant to intercept solid bodies. 11. Hydroelectric plant according to claim 9 or 10, comprising a plurality of hydroelectric groups (1A, 1B, 1C). 12. Hydroelectric plant according to claim 11, characterized in that: said plant comprises a first hydroelectric group (1A) and two further hydroelectric groups (1B, 1C) located downstream of said first group and on the sides thereof; said system also comprises three respective convergent bulkhead systems (20, 23, 24) shaped to direct the water towards said groups, and at least a water-splitting partition which distributes the discharge water flow of said first group (1A) between said two groups (1B, 1C) downstream. 13. Hydroelectric plant according to any of the previous claims, in which one or more hydroelectric groups can be anchored to an existing bridge over the watercourse.