DEVICE FOR GENERATING ELECTRIC CURRENT IN A FLUID CIRCUIT

Description

[0001] The invention lies in the field of generating electric current by means of a fluid (preferably liquid) flowing within a pipe or conduit.

[0002] This generation of electrical current, and more specifically pico-generation of electrical current, is carried out using a transverse-axis hydraulic machine to produce energy to power sensors (or other systems) in areas without connection to the electrical grid. The application of this invention is particularly envisaged for powering sensors monitoring drinking water supply networks. Exposé de l'art antérieur :

[0003] Electricity generation using hydraulic turbomachinery is an old technology dating back over a hundred years. Among all the types of turbines used to date, there are two main categories: impulse turbines and reaction turbines.

[0004] Impulse turbines operate primarily by deflecting a jet of liquid onto a specially designed runner. The most common types of impulse turbines are Pelton and Banki turbines. These machines all share the use of an atmospheric pressure chamber (therefore in contact with the ambient air) to achieve the interaction between the liquid jet and the runner.

[0005] Reaction turbines operate primarily by using the lift generated on their blades to create driving torque. Consequently, these machines are fully immersed in the fluid from which they extract energy.

[0006] The most commonly used turbines are axial turbines (propeller or Kaplan type) and centripetal turbines (Francis type). If the aim is to generate energy by inserting a hydraulic turbomachine into a drinking water distribution network, care must be taken to ensure that it only marginally alters the hydraulic and mechanical characteristics of the network. Therefore, using impulse turbines for such applications is practically inconceivable. Indeed, in this case, maintaining the hydraulic continuity of the supporting piping would be impossible. In particular, a contact zone with air would be necessary for the turbine to operate. This could only be achieved by diverting a small portion of the flow to expand it within the turbine. This diverted flow would be lost to the pipeline because it would be depressurized to atmospheric pressure after passing through the turbine.Therefore, only reaction turbines are suitable for such an application.

[0007] Thus, within the family of different turbines usable for the intended application, two main solutions coexist. On the one hand, there are machines installed upstream of a pipe bend, allowing a shaft to extend from the pipe. This shaft drives the electric generator, which, thanks to this configuration, can be located outside the pipe and thus exposed to the air. On the other hand, there are also machines where the electric generator is integrated within the pipe in a sealed casing (a technology known as bulb turbines). Both approaches are commonly used in hydroelectric power plants worldwide. They each have their advantages and disadvantages, and their use depends on both the turbine technology employed and the specific configuration of the installation.

[0008] However, when considering their use in a pico-generation system installed on a hydraulic circuit (for example, a drinking water network), all of these systems share major drawbacks, which are outlined below. First, there is a sealing issue. Therefore, regardless of the chosen configuration (upstream of the bend with the generator exposed to air or "bulb" mounting with the generator enclosed in a sealed housing), it is essential to ensure a perfect seal on the drive shaft located between the turbine and the electric generator, whether it is submerged in the flow or located outside the pipe.

[0009] Document CN-A-111396231 proposes a device comprising a turbine mounted in a conduit. This turbine has a rotating shaft connected to a generator also mounted in the conduit. The conduit therefore has an orifice into which a ring carrying the generator is inserted to allow the direct transmission of the turbine's rotation to the generator. Such an assembly presents a risk to the sealing of the generator's connection to the conduit.

[0010] In documents US-A-2010 / 0253031, CN-A-105443298, and CN-A-111005833, the described devices have a rotation axis that passes through the conduit wall on both sides and are thus connected to an external generator. Here again, sealing may become a problem over time.

[0011] US-B-10233898 describes a power-generating device interposed in a toilet drainpipe. This device comprises a section of pipe in which a turbine is mounted. The turbine's axis of rotation carries a support for magnets that generate a magnetic flux. This magnetic flux cooperates with the magnetic means of a stator or stator circuit to produce an electric current. The section of pipe is shaped to present a housing in which the turbine, the magnetic flux-generating means, and the stator are mounted. Such a device has the disadvantage of being intended for use in a toilet tank water supply pipe, through which a small volume of water flows, and is therefore unsuitable for use in a potable water supply system. Furthermore, in the event of a failure, the entire device must be removed, causing a water supply interruption, which is unacceptable.

[0012] Furthermore, when used on a support pipe in a water distribution network, it is impossible, without resorting to a bypass system, to discharge high flow rates without generating significant head losses. This aspect makes the use of such turbines (whether axial or centripetal) in hydraulic network pipeline applications (such as drinking water networks) problematic.

[0013] Furthermore, these devices generate geometric complexity and require high standards of mechanical construction quality. Indeed, if axial or centripetal hydraulic turbines are used, achieving good efficiency requires blades with relatively complex geometric characteristics, which are therefore difficult to manufacture economically.

[0014] We are familiar with the geometries of machines described in documents FR-A-3010150, US-A-2012007364, US-A-2010148515, and WO-A-2005080790, which are axial in type and therefore employ fairly complex blade shapes. Furthermore, the machine described in patent application WO-A-2005080790, in particular, has static but adjustable blade grids upstream of the turbine. While this increases its efficiency, it also complicates its construction and thus increases its cost. This adjustment function is performed using variable-incidence blades in the turbine presented in patent US-A-2010148515. This solution results in a highly complex turbine, which is a drawback when the goal is a robust, reliable machine with low construction costs.

[0015] Another problem is the space occupied by the turbine and its supports within the receiving piping. All the machines described in the aforementioned documents share the characteristic of being axial. Therefore, for them to function correctly, their axis of rotation must be strictly parallel to the axis of the fluid flow. Consequently, precisely positioning this axis of rotation requires inserting a whole set of support and guide components into the fluid conduit.

[0016] This whole assembly will, in addition to complicating and increasing the cost of the machine, generate large parasitic pressure losses at the very heart of the pipe which are detrimental to obtaining usable power levels for very low values ​​of the fluid velocity (on the order of 0.5 m / s start-up velocity) while maintaining the lowest possible pressure loss level during these low-speed production sequences and this in order not to unbalance the hydraulic network (for example drinking water) from which energy is drawn.

[0017] Furthermore, the peripheral positioning of the stator or electrical generation stator circuit creates another problem stemming from the fact that all the machines described in the aforementioned documents are axial, and the electrical generation stator circuit is located all around the periphery of the turbine and therefore the piping itself. Consequently, the devices described in these documents do not use a conventional electrical generator on these very low-power turbines designed to be integrated into pipelines. This choice greatly simplifies the problem because, a priori, there is no issue of transmission shaft sealing to manage. However, the drawback of this choice is that, on these axial machines, it will be necessary to install an electrical generation system on the periphery of the blades and therefore also on the piping.In particular, on the machines described in patents FR3010150A1, US2012007364A1 and WO2005080790A1, it is proposed to install permanent magnets around the periphery of the blades. These magnets create a fluctuating magnetic field through the pipe walls, thereby inducing a current in the stator circuit installed around the entire circumference of the pipe, to which it is thus connected.

[0018] Such a choice presents numerous difficult technical problems. Indeed, placing magnets on the periphery of the turbine blades will generate significant centrifugal forces (due to their relatively large mass) and, moreover, requires very rigorous dynamic balancing of the turbine because of the substantial mass at the blade tips. Furthermore, this strategy necessitates surrounding the entire pipe with inductor coils or magnetic circuits to create, on the pipe's periphery, a synchronous machine with a high pole count, specific to the piping and the turbine being used. It is therefore not possible to use a standard, commercially available, mass-produced synchronous machine to drastically reduce this cost.

[0019] Furthermore, in this configuration where current is generated at the turbine's periphery, the air gap between the blade tips and the piping must be as small and uniform as possible. This precaution is essential to minimize magnetic flux losses between the turbine and the stator circuit located on the outer periphery of the pipe. Indeed, such losses could lead to a significant drop in the generator's mechanical-to-electrical conversion efficiency. This requirement therefore imposes very strict manufacturing constraints regarding the tolerances associated with achieving a perfectly constant dimension for the air gap and, above all, maintaining this dimension regardless of the machine's operating conditions. This constraint significantly increases the machine's manufacturing complexity and, consequently, its cost.

[0020] It is likely that the fluid passing through the turbine may contain foreign matter, and the risk of this matter contaminating the air gap is significant. This situation could lead to malfunctions, highlighting the design's lack of robustness with respect to the quality of the turbine fluid. In particular, there could be a risk of damage to the magnets, which are especially vulnerable due to their placement on the periphery of the turbine blades.

[0021] Thus, in documents FR-A-3010150 and WO-A-2005080790, to protect these magnets, it was proposed to install them in annular cavities around the periphery of the wheel, in order to protect it from any foreign matter present in the fluid. However, with this approach, the magnets move at a very high relative speed compared to the fluid trapped in this protective cavity. Therefore, due to the small size of the cavity, a turbulent Couette flow will occur, generating significant hydrodynamic losses through friction at the magnets and thus reducing the overall efficiency of the machine. Furthermore, due to the recirculation phenomenon, the fluid in contact with the magnets is almost entirely enclosed within this protective cavity.Thus, the level of convection is very low inside the cavity, and consequently, very little mass and energy are exchanged with the external fluid circulating in the pipe. This situation, which accumulates hydrodynamic losses due to turbulent Couette flow as well as electromagnetic losses in the air gap in an area where the fluid can exchange very little mass and energy with the outside, will lead to heating of the air gap, which will simultaneously affect the magnets and especially the stator circuit located all around the periphery of the pipe.

[0022] Thus, with this axial machine design, it proves very difficult to properly cool the module that converts mechanical energy into electrical energy. This results in an operating limit that is quickly reached if the temperature rises too high, particularly around the magnets.

[0023] In view of the aforementioned drawbacks concerning the state of the art and the technology currently used, the present invention proposes to remedy said drawbacks by proposing an energy generation device whose simple architecture and implementation allow it to be robust and economically attractive.

[0024] To this end, the present invention aims to provide a device for generating electric current in a fluid flow circuit according to claim 1.

[0025] Advantageously, only the rotor is installed within the conduit segment, simplifying the device's construction. Even more advantageously, the longitudinal ends of the turbine's rotational axis are mounted between and against the opposite walls of the conduit, such that the technical solution proposed by the present invention requires no sealing system. Indeed, the proposed turbine fits naturally into a conduit segment whose ends are configured to form a standard section of piping of any cross-section within a flow circuit.

[0026] The crossflow or transverse flow turbine is a turbine equipped with a vertical axis of rotation around which blades are driven in rotation, the flow of the flow arriving perpendicularly to this axis.

[0027] The turbine thus features ball bearings at the longitudinal ends of its axis of rotation. These bearings are mounted in housings formed on the duct segment to hold the cross-flow turbine within the duct segment and allow the turbine to rotate. These ball bearings are preferably made of ceramic and therefore require neither sealing nor lubrication.

[0028] Preferably, the turbine consists of two hubs, preferably in the shape of a disc, either flat or domed, between which extend blades, preferably two, which can be driven into rotation by the effect of the flow of a fluid in the conduit.

[0029] Each hub has a bearing at its center and carries magnetic flux generation means such as permanent magnets. Preferably, one or both hubs are equipped with permanent magnets around their entire circumference. Thus, the mechanical power generated by the rotation of the blades around the turbine's axis of rotation by the flow in the duct is transferred to the outside of the duct by means of a magnetic field created by the permanent magnets on the rotating hub. Therefore, there is no need for a mechanical transmission system to the outside of the piping, and consequently, no sealing device is required. This feature allows for a device that is simple, robust, and economical.

[0030] According to one embodiment of the turbine, its axis of rotation consists of a shaft extending between the hubs.

[0031] In another embodiment, the turbine's rotation axis consists solely of the two bearings. Advantageously, this dematerializes the rotation axis between the two hubs, resulting in virtually no pressure loss, even at very high flow velocities.

[0032] Preferably, the two blades extend between the hubs symmetrically with respect to the axis of rotation of the turbine and the central part of said blades is driveable in rotation by sweeping a surface inscribed in a cylinder of revolution around the axis of rotation.

[0033] Advantageously, the driving torque of this turbine is transmitted to the outside of the piping via the action of a magnetic field through the wall of the pipe segment. Since the turbine rests on two ball bearings, these are immersed in the fluid, and the device therefore requires neither sealing nor lubrication. This assembly is thus easily compatible with hygiene standards related to the use of drinking water turbines. Indeed, numerous standards exist for equipment immersed in drinking water (food-grade standards), for example, standard XP P41-280 of circular DGS / SD7A No. 571 of November 25, 2002.The main technical constraints involved in complying with these standards consist in fact of avoiding all sealing and / or lubrication systems so as not to risk external contamination of the water at the machine level and then of using materials authorized for food contact such as for example ceramics, food grade stainless steels, etc... The device according to the invention therefore makes it possible to advantageously meet these requirements.

[0034] The device according to the invention can be integrated into a fluid flow circuit, particularly for liquids, comprising conduits whose cross-section may be circular, but also square, rectangular, or any polygonal shape. Furthermore, the device according to the invention can be very small in size. It can thus be installed on drinking water pipes with diameters between 100 and 200 mm.

[0035] The device according to the invention therefore makes it possible to recover the torque of the turbine, outside the conduit, by means of one or more stator circuits installed at the level of the magnetic hub(s) located opposite each other inside the same conduit.

[0036] According to a first embodiment, the stator or stator circuit also constitutes the electrical generator.

[0037] According to a second embodiment, the stator circuit includes one or more magnetic coupling elements, which can be driven in rotation and allow the direct mechanical drive of one or more conventional electric generators.

[0038] According to a third embodiment, the stator circuit includes one or more magnetic coupler-multiplier sets enabling the mechanical drive of one or more mass-produced electric generators.

[0039] Advantageously, the power transfer surface area outside the duct or pipe corresponds to only a small angular sector of the duct and therefore does not require the use of the entire peripheral surface of said duct for the full transmission of the turbine's torque in magnetic form. This simplifies the architecture of the device and reduces its footprint on the piping. The technology proposed here is simple, robust, and therefore durable.

[0040] Indeed, in the case of axial turbines, it is necessary to install an electrical generation unit around the periphery of the blades. Consequently, the induced stator circuit occupies the entire circumference of the support shaft. This leads to rigidity in the machine's architecture because this stator circuit must be custom-designed and is therefore difficult to standardize, making it challenging to achieve substantial cost reductions.

[0041] In the device according to the present invention, a stator circuit mounted on a lateral flange of the conduit is used. This allows the use of magnetic circuits with very simple geometries that can be easily standardized. Furthermore, by using a magnetic coupling element or even a magnetic coupling-multiplier element, standard, low-cost, high-performance electric generators can be used, all without significant losses in power transmission.

[0042] The device according to the invention further features an architecture in which there is no risk of contamination of the electromagnetic air gap by a foreign body present in the fluid because, here, the magnetic flux is transmitted through the duct wall in a very limited area that is protected from the main flow. Advantageously, there is no longer any risk of overheating of the stator circuit since it is located outside the duct and can thus be easily equipped with a finned heat sink, which will be more than sufficient to dissipate the few watts of heat loss that occur when using the device according to the invention to power sensors along a drinking water supply circuit.

[0043] Advantageously, in the event of high flow rates occurring in the flow circuit containing a device according to the invention, the latter includes means for immobilizing the turbine with its blades oriented in the direction of the flow. In this position, the preferably two-bladed turbine with a transverse axis of rotation, which is "dematerialized" between the two hubs according to one of the embodiments, offers very low drag and induces virtually no pressure loss, even at very high flow velocities. Therefore, a bypass system can be dispensed with by using a device according to the invention. The device and its control system are thus greatly simplified, resulting in a reduction in cost and an increase in reliability.

[0044] In particular, we avoid that, in emergency situations which may occur and generate high flow rates in the flow circuit, for example in the event of a pipe rupture on the hydraulic network downstream of the turbine or when using a fire hydrant, very high flow velocities do not endanger the mechanical integrity of the turbine.

[0045] Furthermore, this avoids the need for a bypass system, which would be necessary when using an axial flow turbine. Indeed, in the case of an axial flow turbine, once it stops, the head loss is far too great to properly perform this discharge function. Moreover, since it is difficult to ensure that these turbines can withstand such speeds without oversizing them, there would be a risk of rendering them virtually inoperative (or having very low efficiency) when operating at very low flow speeds (on the order of 0.5 m / s), which is typical of everyday use.

[0046] According to another advantage of a device according to the invention, the transverse-axis turbine used in the present invention allows the use of symmetrical and identical hydraulic profiles along the entire length of a blade. Furthermore, blades with a constant chord along their entire length and free from twist can be used. Consequently, manufacturing can be greatly simplified compared to axial turbine blades, for example, which require a complex, three-dimensional blade geometry, especially since the hydrodynamic profile often changes between the root and the tip of the blade. In particular, blade profiles can be produced by pultrusion of composite materials and then bent to obtain a circular shape. Alternatively, a die can be used to extrude a profile base from food-grade stainless steel and then bent to the desired circular shape.All these processes are economical and allow for small or large quantity production at low costs.

[0047] Furthermore, horizontal-axis turbines require bearing and support systems in the middle of the pipe to ensure proper guidance of the turbine wheel. In contrast, the transverse-axis turbine used in the present invention does not require a support structure in the center of the piping, thus drastically simplifying the device. Indeed, unlike axial turbines, no fixed structure partially obstructs the fluid flow within the pipe. This results in a much lower parasitic head loss and therefore less disruption to the grid from which energy is drawn.

[0048] Advantageously, the device according to the invention can be used for pico-generation of electrical energy to power electrical devices such as monitoring sensors on fluid flow circuits, such as drinking water networks. Indeed, it is possible that in the very near future, legislation will require all drinking water networks to be equipped with a very dense network of monitoring sensors to determine loss rates and also monitor certain chemical parameters of the water, such as, in particular, the presence of toxic substances in the water, which may occur either accidentally or as a result of malicious acts. The device according to the invention therefore offers a simple and efficient solution for powering these sensors.

[0049] Furthermore, it is observed that in most places where these sensors are installed or can be installed, it is not always simple and economical to connect to the electrical network in order to power these sensors.

[0050] The solution currently used by operators is therefore to use batteries with a lifespan of between one and three years. For example, there is a sensor known commercially as the VEOLIA KAPTA 3000-AC4, which is battery-powered. This battery-powered solution remains the most widely used because the number of sensors on the networks is still relatively small, and operators are not yet required to finance the recycling of used batteries.

[0051] However, as previously mentioned, with the introduction of new European regulations concerning the monitoring of drinking water networks, thousands of sensors will need to be installed to meet the required network density. Consequently, battery-powered solutions will become prohibitively expensive, both in terms of purchase and recycling costs, and also in terms of additional maintenance costs if frequent battery replacements are required for the thousands of sensors operating across the networks.

[0052] The installation of electrical energy generation devices according to the invention in drinking water distribution networks makes it possible to supply the sensors with energy in a reliable, robust and economical manner.

[0053] The present invention also relates to a fluid flow circuit comprising at least one electrical device such as a sensor, characterized in that said circuit comprises an electrical energy generation device according to the invention integrated into the circuit, intended to supply the sensor with electrical energy.

[0054] The present invention also relates to a cross-flow turbine according to claim 17.

[0055] The invention will now be described in more detail with reference to the figures which represent: [ Fig. 1 ] an exploded perspective view from above of a first embodiment of a device according to the invention; [ Fig. 2 a forward perspective view of the implementation method of the figure 1 ; Fig. 3 a side perspective view of the device figure 1 ; Fig. 4 a longitudinal cross-sectional view along the cutting plane AA of the figure 2 ; Fig. 5 an exploded perspective view from above of a variant of the device figure 1 ; Fig. 6 a forward perspective view of the implementation method of the figure 5 ; Fig. 7 a side perspective view of the device figure 5 ; Fig. 8 ] an exploded perspective view from above of a second embodiment of the invention; [ Fig. 9 an exploded perspective view from above of a variant of the device figure 8 ; Fig. 10 ] an exploded perspective view from above of a third embodiment of the invention; and [ Fig. 11 an exploded perspective view from above of a variant of the device figure 10 [ Fig. 12 ] an exploded perspective view of another embodiment of a device according to the invention; [ Fig. 13 a side perspective view of the device figure 12 ; And [ Fig. 14 a cross-sectional view along the section line AA of the figure 13 .

[0056] The electric current generation device according to the invention comprises a conduit segment 1 in which a rotor 2 is mounted. A stator 3 is installed on the outer periphery of the conduit 1 to cooperate with the rotor 2.

[0057] The rotor 2 consists of a cross-flow turbine installed in the conduit segment 1 such that the axis of rotation A of the turbine 2 extends transversely in the conduit segment 1. This turbine 2, of circular section, has two blades 22 and is transversely axis-bound.

[0058] This turbine 2 consists of two hubs 21 between which extend blades 22, preferably two. These blades 22 are mounted symmetrically with respect to the axis of rotation A of the turbine 2 and are free to rotate about the axis A under the effect of a fluid flow F flowing in the conduit 1.

[0059] When in motion, the blades 22 sweep a surface inscribed in a cylinder of revolution around the axis A.

[0060] Each blade 22 extends between the hubs 21 along a curve that substantially follows the circular cross-section of the duct, but any type of blade from cross-flow turbines can be used provided that the central part of the blade sweeps a cylinder of revolution. The blades can also be U-shaped, or any suitable shape. Preferably, the blade tips are fixed to the hubs. Preferably, the turbine blades 22 are produced by pultrusion of composite materials and then bent to obtain a circular cross-section. In particular, they can be produced from extruded, food-grade stainless steel and then bent to obtain a circular cross-section.

[0061] Each means 21, 21' is presented in the form of a convex disc in the shape of a cup or dome as represented in the figure 1 or plan as shown in the figure 12 driven in rotation by the blades 22. One of its hubs 21 contains permanent magnets 23 which are positioned to face the wall of the duct segment 1. The varying magnetic flux is transmitted through the wall of the duct 1 and induces, within windings of the stator circuit 3 positioned outside the duct 1 opposite this end of the turbine 2, an electric current which is then exploited.

[0062] The second 21' hub in this example is devoid of permanent magnets.

[0063] To the figure 5 is represented a variant of this first embodiment in which, for applications where a higher torque to be transmitted is required, a second hub 21 carrying magnets 23 and arranged opposite the first on the conduit 1 is used. Thanks to this device, the transmissible torque can be doubled.

[0064] The two-bladed transverse axis turbine 2 is therefore intended to be an integral part of a conduit of any cross-section (circular as shown in the figures but also, square, rectangular or any polygonal shape) in which a fluid, in particular a liquid, flows.

[0065] This turbine 2 is held in the conduit by two bearings 24 formed in the center of the domed disc-shaped hubs 21. These two bearings 24 hold the turbine against the opposite walls of the conduit segment 1, these bearings preferably being housed in recesses provided for this purpose in the wall of the conduit segment 1 so that the axis of rotation A of the turbine is orthogonal to the axis of the fluid flow F. Thus, this retention of the turbine 2 in the conduit segment 1 requires neither sealing nor lubrication. The power of the turbine 2 is transmitted to the outside of the conduit via a magnetic device using one or more hubs fitted with permanent magnets around their entire circumference. As can be seen in the figures 12 And 14 , the conduit segment 1 may include housings 13 in which the bearings 24 are mounted. The hubs 21 are mounted to be rotateable around the bearings 24.

[0066] The transfer surface of this power towards the outside of the conduit segment 1 corresponds only to a small angular sector of said conduit segment and does not require the use of the entire peripheral surface of said conduit segment for the full transmission of the turbine torque in magnetic form.

[0067] To figures 8 And 9 A device according to the invention is shown, comprising a turbine 2 of the same type as those in the preceding figures, in which a magnet-carrying element 4 is placed outside the conduit to transmit the mechanical torque of the turbine. This magnet-carrying element 4 can thus be connected to a standard electric generator 5 (for example, a radial flux permanent magnet synchronous generator) produced in large quantities.

[0068] Thus, under the effect of the flow of fluid F, the blades 22 are driven in rotation, which in turn drives the hub 21 carrying magnets 23 in rotation. The magnet-carrying element 41, positioned opposite, is also driven in rotation. This magnet-carrying element 41 is connected by a shaft 6 to a generator 5. The entire assembly of the magnet-carrying element 41 and shaft 6 is enclosed in a housing 7.

[0069] To the figure 9 is shown a variant with a second generator, for applications requiring high torques.

[0070] This design offers both a very low cost price and very good efficiency. It can also be noted that this design can be combined with a square or rectangular cross-section conduit to limit the air gap between the two magnetic supports, inner (hub) and outer (magnet carrier), thus ensuring good transmission.

[0071] To figures 10 And 11 are shown an embodiment of the device of the invention in which an external magnetic coupling element 42 is used in combination as a stator circuit with a magnetic multiplier 8 in order to increase the rotational speed of the output shaft so as to be able to use a high-speed permanent magnet synchronous generator 9.

[0072] This design achieves excellent conversion efficiencies (mechanical to electrical) while using high-performance, very inexpensive generators. Furthermore, the magnetic multiplier introduces virtually no losses and can be very economical to produce if a sufficient number are manufactured. It should also be noted that this design can be combined with a square or rectangular cross-section conduit to minimize the air gap between the two inner and outer magnetic barrels, thus ensuring efficient torque transmission to the outside.

[0073] In the examples shown above, the axis of rotation A of the turbine 2 consists solely of the bearings 24 around which the hubs 21 carrying the blades 22 are driven in rotation.

[0074] To figures 12 à 14 is shown an example of an embodiment of the device according to the invention in which a shaft 25 extends centrally between the two hubs 21 thus constituting the axis of rotation A extending transversely in the conduit segment 1.

[0075] As can be seen in figures 12 And 14 , the conduit segment 1 is shaped to present in its opposite walls, two orifices 11 in which are housed the ends of the turbine 2, held in place by two hoods 12.

[0076] The hubs 21 are made of two flat discs, at least one of which has magnets 23 on its periphery. Each hub 21 has a bearing 24 at its center and a shaft 25 extending between the two hubs 21 and forming the axis of rotation A of the turbine. A cover 12 is fitted onto each hub 21 and has a housing 13 in which a bearing 24 and one end of the turbine's shaft 25 are positioned. The bearing 24 is fixed in the housing 13 of the duct segment 1, and the shaft 25 is rotatable and fixed to the hubs 21. This results in a device that is simple to implement and whose simple structure also gives it great robustness. The blades 22 extend diametrically opposite each other on either side of the axis of rotation A between the hubs 21, with their ends connected to the hubs 21.

Claims

1. Device for generating electrical current in a fluid flow circuit, comprising: a duct segment (1), intended to be interposed in the fluid flow circuit, a rotor (2) mounted in the duct segment (1) and capable of being moved by the passage of a fluid in said device, and a stator or stator circuit (3) arranged to cooperate with the rotor (2) and produce the electrical current, the rotor (2) consisting of a transverse-flow turbine (2) whose axis of rotation (A) extends across the duct segment (1), the turbine (2) including, at the longitudinal ends of its axis of rotation (A), means (24) the holding against opposite walls of the duct segment (1), the stator or stator circuit (3) being positioned outside the duct segment (1) at an end of the turbine (2) which can be driven in rotation during the movement of the turbine (2), and comprises means for generating a magnetic flux (23) to cooperate with said stator or stator circuit (3) to produce the electrical current, characterised in that the turbine (2) has bearings (24) on ball bearings at the longitudinal ends of its axis of rotation, the turbine (2) consisting of two hubs (21, 21') between which blades (22) extend, preferably two, rotatably driveable under the effect of the flow of a fluid in the duct, each hub (21, 21') having a bearing (24) and at least one of the hubs (21) carrying the means for generating a magnetic flux (23).

2. Device according to claim 1, characterised in that said bearings (24) are mounted in housings (14) provided on the duct segment (1) to keep the turbine (2) transverse in the duct segment (1) and allow the rotation of the turbine (2).

3. Device according to claim 2, characterised in that the ball bearings are made of ceramic.

4. Device according to one of claims 1 to 3, characterised in that the means for generating a magnetic flux are permanent magnets (23).

5. Device according to one of claims 1 to 4, characterised in that each blade (22) extends between the hubs (21), the central part of a blade (22) sweeping a cylinder of revolution about the axis of rotation (A).

6. Device according to claim 5, characterised in that the blades (22) of the turbine are produced by pultrusion of composite materials and then curved.

7. Device according to claim 5, characterised in that the blades (22) of the turbine are produced from food-grade stainless steel extruded in a die and then curved.

8. Device according to one of claims 1 to 7, characterised in that a hub (21, 21') consists of a flat disc.

9. Device according to one of claims 1 to 7, characterised in that a hub (21,') consists of a disc curved in the form of a dome.

10. Device according to one of claims 1 to 9, characterised in that the axis of rotation (A) of the turbine consists of a shaft (25) extending between the hubs (21, 21').

11. Device according to one of claims 1 to 9, characterised in that the axis of rotation (A) of the turbine consists only of the two bearings (24).

12. Device according to one of claims 1 to 7, characterised in that the stator or stator circuit also constitutes the electrical generator.

13. Device according to one of claims 1 to 7, characterised in that the stator or stator circuit comprises one or more magnetic coupler elements, rotatably driveable and enabling direct mechanical driving of one or more electrical generators.

14. Device according to one of claims 1 to 7, characterised in that the stator or stator circuit comprises one or more magnetic coupler-multiplier assemblies enabling the mechanical driving of one or more electrical generators.

15. Device according to one of claims 1 to 11, characterised in that the ends of the duct segment (1) are provided with means for fastening in the flow circuit.

16. Fluid-flow circuit including at least one electrical apparatus such as a sensor, characterised in that said circuit includes an electrical energy generation device according to one of claims 1 to 11, integrated in the circuit, and intended to supply the electrical apparatus with electrical energy.

17. Transverse-flow turbine, including two blades (22) extending between two hubs (21, 21') aligned on the axis of rotation A, the central portion of said blades (22) being rotatably drivable while sweeping a surface inscribed in a cylinder of revolution about the axis of rotation A, intended for use in a device according to one of claims 1 to 15, characterised in that each hub (21) is in the form of a flat or curved disc driven in rotation by the blades (22), at least one of its hubs (21) including means for generating a magnetic flux, holding means aligned with the axis of rotation A being carried by each hub (21, 21').