VALVE WITH A PIEZOELECTRIC ACTUATOR

Description

Technical field.

[0001] The present invention relates to a valve comprising a piezoelectric actuator and a method for accelerating the opening / closing of such a valve. The invention further relates to an electricity generation system comprising such a valve.

[0002] The invention relates to the technical field of valves using a piezoelectric actuator to control their opening / closing and more specifically, but not exclusively, to the field of ultra-fast valves (opening / closing time equal to or less than 1.5 ms). State of the art.

[0003] In the following, the invention is illustrated mainly in connection with a hydraulic fluid, but of course the invention is not limited to this application and can be used with a gaseous fluid.

[0004] Hydraulics is used in many fields thanks to its very high power density (power per unit volume). For example, it is frequently used in devices such as lifting equipment, wind turbines, and in precision fields like aeronautics, drones, and spacecraft.

[0005] Valves are typically used to control the flow of fluid between multiple actuators integrated into these devices at rated power levels. Ultra-fast valves are particularly advantageous for controlling the flow of fluid between these high-frequency actuators, depending on the required power output. Indeed, the shorter the valve's response time, the greater the overall system accuracy and the greater the number of actuators that can be used, thus improving energy efficiency.

[0006] Prior art describes a large number of valves which are essentially divided into two main families: hydraulically operated valves and electrically operated valves.

[0007] Hydraulically actuated valves open and close in response to a pressure command (in a secondary circuit). These valves have a minimum response time of 1.5 ms to 2 ms for the best models, but are bulky due to their multiple stages and require a constant high-pressure fluid supply.

[0008] Electrically operated valves open and close in response to an electrical command. These valves have a minimum response time of 3 ms to 4 ms for the best models. This type of valve allows for more direct control, particularly by using electrical signals to control electromagnetic actuators (solenoid type). However, their response time is quite long, mainly due to the inertia of the coils used. Furthermore, the force density provided by these electromagnetic actuators is generally low (depending on the size of the coils).

[0009] Integrating a piezoelectric actuator into an electrically actuated valve increases its performance, not only in terms of response time but also in terms of force density. However, the displacement of a piezoelectric actuator is generally small (a few tens of microns), so the fluid flow rate that can pass through the valve is low.

[0010] To remedy this, so-called "Hörbiger plate" valves were developed, notably by the University of Bath (hereafter referred to as the "Bath valve") and described in the following publications: David T. Branson et al. "Dynamic simulation model of hydraulic valve utilizing the Hörbiger plate principal and piezoactuation to achieve high bandwidth and flow performance". Proceedings of the IMECE2008-67401, 2008 AMCE. David. T. Branson et al. "Piezoelectrically actuated hydraulic valve design for high bandwidth and flow performance". Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 2011, pp. 225-345.

[0011] The Bath valve comprises a fixed plate P and a movable flap C opposite said plate. The principle is based on fluid passage channels in the form of annular grooves Rp, Rc formed in the plate and the flap. As illustrated in the figure 1aWhen the valve C is separated from the plate P, the fluid F passes through the channels Rp, Rc, whose annular groove configuration significantly increases the overall flow area compared to traditional valve configurations. This makes it possible to obtain high flow rates even with a small displacement xs of the valve C (a few tens of microns). The fluid flow rates that can pass through the valve are approximately 65 L / min at 20 bar (2 MPa) with opening / closing times of less than 1.5 ms. In the closed position ( figure 1b ), the valve C is in contact with the plate P so that the channels Rp, Rc are no longer in fluidic communication.

[0012] With reference to figures 2a And 2b The Bath valve comprises a pressurized fluid inlet E and a fluid outlet S. In the open position ( figure 2b), the valve C is spaced from the fixed plate P so that the fluid flows from the inlet E to the outlet S, passing through the channels Rc, Rp. A piezoelectric actuator A is disposed in a first chamber Vh and acts on an active face of the valve C so as to move it between the closed position ( figure 2a ) and the opening position ( figure 2b The inlet E (high pressure) is located upstream of the plate P and is fluidically connected to the channels Rp of the plate P. The outlet S (low pressure) is fluidly connected to the channels Rc of the valve C so that in use, in the open position, the fluid F flows from the channels Rp of the plate P to the channels Rc of the valve C.

[0013] The Bath valve is interesting, but it has some limitations. First, the maximum actual (not simulated) operating pressure is in the range of 10 to 20 bar, and serious leakage problems occur above these pressures. The Bath valve's range of applications is therefore limited. Second, while the opening / closing times are short (1 to 1.5 ms), they are still comparable to the highest-performing hydraulically actuated valves on the market. For these reasons, there is little practical advantage to using a Bath valve in an industrial setting.

[0014] Other piezoelectric actuator valves are also known from patent documents US2013 / 0048898 and US2017 / 0211716. In patent US2013 / 0048898, a leaf spring engages the valve to move it to the open or closed position, depending on the embodiment. Due to this design, when the valve is subjected to high fluid pressures, its opening / closing times are relatively slow, primarily due to the pressure force exerted on the active face of the valve. The same is true for the valve described in patent US2017 / 0211716, as the pressure force exerted on the active face of the valve slows its movement to the open or closed position.

[0015] The invention aims to overcome all or part of the aforementioned drawbacks. In particular, the present invention intends to provide a valve whose design is based on the principle of the Bath valve (a Hörbiger plate valve with a piezoelectric actuator) which, under real operating conditions (and not just simulated conditions), is capable of operating at pressures significantly higher than 20 bar, potentially reaching several hundred bar. Another objective of the invention is to provide a valve with reduced opening / closing times compared to prior art valves, especially when said valve is subjected to high fluid pressures (≥ 100 bar). Presentation of the invention.

[0016] The solution proposed by the invention is a valve comprising a pressurized fluid inlet and a fluid outlet, which valve includes: a fixed plate in which first fluid passage channels are arranged, a valve in which second fluid passage channels are arranged, said valve being mounted movable between: - an open position in which the first channels and the second channels are in a configuration allowing the passage of fluid between the inlet and the outlet;- and a closed position in which the first and second channels are in a configuration blocking the passage of fluid between the inlet and outlet, which inlet is arranged so that in use, the pressurized fluid exerts a pressure force on an active face of said valve, forcing said valve towards the closed position; a piezoelectric actuator acting on the valve to move it between the closed position and the open position, which actuator consists of a piezoelectric pillar formed by a stacked structure of piezoelectric elements, which pillar extends when the actuator is energized and retracts when said actuator is not energized.

[0017] The operation of the valve of the invention is reversed compared to the Bath valve. The pressurized fluid now acts on the movable flap in the closing direction, whereas in the Bath valve, the fluid pressure acts on the movable flap in the opening direction. In other words, in the invention, the high-pressure position is located upstream of the movable flap and acts mechanically in the direction of the piezoelectric actuator during the closing phase, thus contributing to improved valve sealing. Therefore, the higher the fluid pressure, the better the seal, so the valve can now operate at pressures exceeding 100 bar and up to several hundred bar.

[0018] According to one embodiment, the actuator is further axially prestressed by means of one or more prestressing rods forming spring elements whose restoring force acts in the direction of the retraction of the piezoelectric pillar.

[0019] These prestressing rods increase the retraction speed of the piezoelectric pillar tenfold. The plaintiff observed that the opening and closing times were on the order of 0.5 ms, which is significantly faster than prior art valves.

[0020] Furthermore, due to its relatively simple design and actual performance, the valve that is the subject of the invention is industrially exploitable, with reduced manufacturing costs.

[0021] Other advantageous features of the valve that is the subject of the invention are listed below. Each of these features may be considered alone or in combination with the features defined above. Each of these features contributes, where applicable, to solving specific technical problems defined further in the description and in which the notable features defined above do not necessarily participate. These latter features may, where applicable, be the subject of one or more divisional patent applications.

[0022] According to an embodiment allowing the best results in terms of opening / closing speed, the prestressing force applied by the prestressing rod(s) on the piezoelectric pillar is between 5% and 20% of the mechanical force delivered by said piezoelectric pillar alone (i.e. without prestressing) and / or the prestressing rod(s) have a stiffness between 10% and 20% of the stiffness of the piezoelectric pillar alone.

[0023] In one embodiment, in the open position, the valve is spaced from the plate such that the first and second channels are in fluidic communication. And in the closed position, the valve is in contact with the plate so that the first and second channels are not in fluidic communication.

[0024] According to one embodiment: - the valve is mounted movable in a chamber between the open position and the closed position; - the second channels are in fluidic communication with the chamber; - the inlet is disposed upstream of the valve, at the level of the chamber; - the outlet is disposed downstream of the plate, in fluidic communication with the first channels so that in use and in the open position, the fluid flows from the second channels to said first channels.

[0025] According to one embodiment, the piezoelectric actuator is configured so that the valve is naturally in the open position when said actuator is not energized, the prestressing rod(s) being configured so that the restoring force exerted by said rod(s) acts against the pressure force which is exerted, in use, on the active face of said valve when said valve moves from the closed position to the open position.

[0026] In one embodiment, the piezoelectric actuator is configured so that the valve is naturally in the closed position when said actuator is not energized, the preload rod(s) being configured so that the restoring force exerted by said rod(s) combines with the pressure force exerted, in operation, on the active face of said valve when said valve moves from the open position to the closed position.

[0027] According to one embodiment, the valve is arranged between the actuator and the plate.

[0028] According to one embodiment, the plate is arranged between the actuator and the valve.

[0029] According to one embodiment: - the piezoelectric elements of the actuator are mounted on a pre-stressed rod installed along a translation axis; - the rod is engaged with the valve so that a translation of said rod induced by the piezoelectric actuator causes the translation of said valve between the open and closed positions.

[0030] According to one embodiment, the plate has a central orifice in which the rod is housed, said orifice acting as a guide for said rod.

[0031] According to one embodiment: - the piezoelectric actuator has, at one of its ends, a connecting piece on which the valve is fixed; - the valve has, at one face, a protruding element adapted to be fixed on the connecting piece.

[0032] According to one embodiment: - the flap has, on another face, another projecting element extending towards the plate; - the plate has a central orifice in which said other projecting element is housed, said orifice acting as a guide for said other projecting element.

[0033] Another aspect of the invention relates to an electricity generation system comprising: a circuit in which a pressurized fluid circulates, at least one fluidic cavity arranged on at least a portion of the circuit, which cavity houses a piezoelectric generator connected to an electronic charge extraction circuit capable of recovering the electrical energy from said piezoelectric generator, and in which: The fluidic cavity is installed between two valves conforming to one of the preceding characteristics, respectively an inlet valve and an exhaust valve. In a first operating sequence, the inlet valve is actuated so that its flap is in the open position and the exhaust valve is actuated so that its flap is in the closed position, so that the pressurized fluid enters and at least partially fills the fluidic cavity in such a way as to generate a mechanical pressure on the piezoelectric generator, which pressure causes a deformation of said generator generating electrical energy recovered by the electronic charge extraction circuit. In a second operating sequence, the inlet valve is actuated so that its flap is in the closed position and the exhaust valve is actuated so that its flap is in the open position.so that the pressurized fluid escapes from the fluidic cavity and the piezoelectric generator is no longer constrained.

[0034] According to one embodiment, the opening / closing frequency of the intake and exhaust valves is controlled so that it corresponds to the resonance frequency of the piezoelectric generator.

[0035] In one embodiment, the intake valve is such that the valve is arranged between the actuator and the plate. And the exhaust valve is such that the plate is arranged between the actuator and the valve.

[0036] Yet another aspect of the invention relates to a method for accelerating the opening / closing of a valve, which valve comprises a pressurized fluid inlet and a fluid outlet, and includes: a fixed plate in which first fluid passage channels are provided, a valve in which second fluid passage channels are provided, said valve being mounted movable between: - an open position in which the first and second channels are in a configuration allowing the passage of fluid between the inlet and outlet; - a closed position in which the first and second channels are in a configuration blocking the passage of fluid between the inlet and outlet, a piezoelectric actuator acting on the valve to move it between the closed position and the open position, which actuator consists of a piezoelectric pillar formed by a stacked structure of piezoelectric elements, which pillar extends when the actuator is energized and retracts when said actuator is not energized.

[0037] This process is remarkable in that it includes the steps of: arrange the inlet so that in use, the pressurized fluid exerts a force on an active face of the valve, forcing said valve towards the closed position; and axially pre-stress the actuator by means of one or more pre-stressing rods forming spring elements whose restoring force acts in the direction of the retraction of the piezoelectric pillar. Brief description of the figures.

[0038] Other advantages and features of the invention will become clearer upon reading the description of a preferred embodiment which follows, with reference to the attached drawings, which are provided as illustrative and non-limiting examples and on which: [ Fig. 1a The aforementioned illustration demonstrates the operating principle of a Hörbiger plate valve, with the valve in the open position. Fig. 1bThe aforementioned illustration demonstrates the operating principle of a Hörbiger plate valve, with the valve in the closed position. Fig. 2a The aforementioned is a schematic cross-sectional view of a Bath valve of the anterior artery, with the flap in the closed position. Fig. 2b The aforementioned is a schematic cross-sectional view of a Bath valve of the anterior artery, with the flap in the open position. Fig. 3 [ ] is a schematic representation showing the arrangement of a valve according to the invention in an installation. Fig. 4a [ ] is a schematic cross-sectional view of a valve according to a first embodiment of the invention, the valve being in the open position. ] Fig. 4b ] is a schematic cross-sectional view of the valve of the figure 4a , the valve being in the closed position. Fig. 5a [ ] is a schematic cross-sectional view of a valve according to a second embodiment of the invention, the valve being in the open position. ] Fig. 5b] is a schematic cross-sectional view of the valve of the figure 5a , the valve being in the closed position. Fig. 6a [ ] is a schematic cross-sectional view of a valve according to a third embodiment of the invention, the valve being in the open position. ] Fig. 6b ] is a schematic cross-sectional view of the valve of the figure 6a , the valve being in the closed position. Fig. 7a [ ] is a schematic cross-sectional view of a valve according to a fourth embodiment of the invention, the valve being in the open position. ] Fig. 7b ] is a schematic cross-sectional view of the valve of the figure 7a , the valve being in the closed position. Fig. 8 ] is a cross-sectional view along AA of the plate illustrated on the figure 4a . [ Fig. 9 ] is a cross-sectional view along BB of the valve illustrated on the figure 4a . [ Fig. 10 [ ] is a schematic representation showing the arrangement of a piezoelectric generator in a system according to the invention. Fig. 11 ] is a schematic representation showing the arrangement of several piezoelectric generators in a system according to the invention. Description of the implementation methods.

[0039] As used here, and unless otherwise indicated, the use of the ordinal adjectives "first," "second," etc., to describe an object simply indicates that different occurrences of similar objects are being mentioned and does not imply that the objects thus described must be in any given sequence, whether in time, space, ranking, etc. The adverbs "upstream" and "downstream" are used in relation to the flow of fluid in the valve and / or the hydraulic circuit in which the valve is installed.

[0040] With reference to the figure 3The valve V of the invention is primarily intended to be integrated into a conduit 10 to allow or prevent the flow of fluid in said conduit. In one embodiment, the conduit 10 is equipped with a pump 11 for pressurizing the fluid. The conduit 10 is also connected to a fluid reservoir 12. Various actuators and / or devices 13a, 13b, 13c (cylinder, pump, motor, brake, etc.) can be connected to different portions of the conduit: between the pump 11 and the valve V and / or between the valve V and the reservoir 12 and / or between the reservoir 12 and the pump 11. The valve V can also be used in an electricity generation system as explained later in the description.

[0041] The invention is illustrated primarily in relation to a hydraulic fluid, but of course the invention is not limited to this application and can be used with other fluids, including gaseous fluids. The hydraulic fluid can be used as a means of power transmission in a hydraulic system. For example, it could be an incompressible mineral oil capable of rapidly transmitting energy from a pump to the actuators and / or devices 13a, 13b, 13c.

[0042] Valve V is a Bath valve, i.e., a Hörbiger plate valve operated by a piezoelectric actuator. It comprises a pressurized fluid inlet E and a fluid outlet S. In one embodiment, the outlet S is a low-pressure outlet, for example, connected to a reservoir 12 pressurized to atmospheric pressure (1 bar). In another embodiment, the outlet S is an outlet where the fluid is always pressurized. Valve V has a fixed plate P and a movable flap C opposite said plate.

[0043] For ease of assembly and design, plate P has a generally cylindrical shape with a circular cross-section. On the figures 4a And 4b It has a shoulder Pe ensuring its positioning in the valve body Vc. The valve body Vc is rigid, for example made of steel, preferably obtained by casting and machining.

[0044] The plate P has two opposing faces, Pf1 and Pf2. The first face, Pf1, is opposite the valve, C. The plate P is rigid. In a preferred embodiment, it is made of steel, preferably machined. Its diameter is, for example, between 10 mm and 50 mm, and its height (or thickness) between 2 mm and 10 mm. The plate P is held in position within the valve body, Vc, for example, by a press fit or by welding.

[0045] Initial fluid passage channels Rp are incorporated into plate P. Depending on the embodiment of the figure 8 These Rp channels take the form of concentric annular grooves, the number of which can vary from 1 to 10 depending on the diameter of the plate P. For example, the Rp grooves have a width between 0.5 mm and 10 mm and a depth between 0.5 mm and 10 mm. Depending on the embodiment of the figures 4a , 4b And8 The grooves Rp open onto the first face Pf1, but are not through-grooves, meaning they do not extend through the entire thickness of the plate P. In other words, they have a bottom wall Rpf. Holes Rpp are drilled into this bottom wall Rpf and open onto the second face Pf2. The channels Rp are thus formed by the annular grooves and the holes Rpp. The diameter of the holes Rpp corresponds to the width of the grooves Rp. Their number can vary from 4 to 20 per groove. This design offers several advantages: it results in a particularly rigid plate P, which prevents or limits deformation and therefore the risk of leakage. Furthermore, it allows for negligible pressure losses during fluid flow.

[0046] In another embodiment, the Rp channels take the form of concentric annular groove segments, the number of which can vary from 1 to 10 depending on the diameter of the plate P. For example, the groove segments Rp have a width between 0.5 mm and 10 mm and a depth corresponding to the thickness of the plate P. In one embodiment, the groove segments Rp are through-holes, meaning they extend through the entire thickness of the plate P and open at the first face Pf1 and the second face Pf2. This design results in a rigid plate P that prevents or limits deformation. Furthermore, negligible pressure losses are observed during fluid flow. This design is similar to that of the first Rp channels described earlier, particularly with reference to the figure 9 .

[0047] For ease of assembly and design, the valve C also has a generally cylindrical shape with a circular cross-section, and more generally the same shape, or substantially the same shape, as the plate P. The valve C is rigid, for example made of steel, preferably obtained by casting and machining. It is mounted to move between an open position ( figures 4a , 5a , 6a , 7a ) and a closing position ( figures 4b , 5b , 6b , 7b ).

[0048] With reference to figures 4a And 4bThe valve C has two opposing faces, Cf1 and Cf2. The second face, Cf2, of the valve C is opposite the first face, Pf1, of the plate P. In a preferred embodiment, the valve C is made of steel, preferably machined. Its diameter corresponds to that of the plate P and is, for example, between 10 mm and 50 mm, with a height (or thickness) between 2 mm and 10 mm.

[0049] Second fluid passage channels Rc are provided in plate P. Depending on the embodiment of the figure 9 These channels Rc are in the form of concentric annular groove segments, the number of which can vary from 1 to 10 depending on the diameter of the valve C. For example, the groove segments Rc have a width between 0.5 mm and 10 mm and a depth between 0.5 mm and 10 mm. Depending on the embodiment of the figures 4a , 4b , 5a , 5b , 6a ,6b , 7a , 7b And 9 The groove segments Rc are through-grooves, meaning they are made through the entire thickness of the valve C and open at the first face Cf1 and the second face Cf2. This design not only makes it possible to obtain a particularly rigid valve C which prevents or limits deformations, but also to generate negligible pressure losses during the passage of the fluid.

[0050] The first Rp channels and the second Rc channels are in a cooperative configuration. Referring to the figures 4a , 4b , 8 And 9 , plate P and valve C have, respectively at the level of the first Pf1 and the second face Cf2, hollow parts (corresponding to the channels Rp, Rc) and solid parts bordering said hollow parts (corresponding to the hatched areas).

[0051] When the valve C and the plate P are opposite each other, the first channels Rp of said plate are arranged opposite the solid parts of said valve. And the second channels Rc of valve C are arranged opposite the solid parts of plate P. In the closed position ( figures 4b , 5b , 6b , 7b When the valve C is in contact with the plate P, the first channels Rp are blocked by the solid parts of the valve, and the second channels Rc are blocked by the solid parts of the plate. Thus, in the closed position, the first channels Rp and the second channels Rc are not in fluidic communication. To effectively block the channels Rp and Rc, the complementary solid parts are wider than the channels themselves, for example, 0.2 mm to 2 mm wider.

[0052] Conversely, in the open position ( figures 4a , 5a , 6a , 7aWhen the valve C is separated from the plate P, the first channels Rp are no longer obstructed by the solid parts of said valve, and the second channels Rc are no longer obstructed by the solid parts of said plate. The first channels Rp and the second channels Rc are then in fluidic communication.

[0053] The valve C is moved between the closed and open positions by a piezoelectric actuator A adapted to generate mechanical energy when electrically polarized. The actuator A consists of a stacked structure of piezoelectric elements (also referred to hereafter as the "piezoelectric pillar") or a piezoelectric membrane. The piezoelectric elements are advantageously in the form of piezoceramic or piezocomposite washers or discs with diameters ranging, for example, from 5 mm to 50 mm. The number of washers or discs can vary from 3 to 400 depending on the pillar length (which can range from 5 mm to 200 mm) and / or the mechanical force to be generated. As an example, hard PZT (Lead Zirconate Titanium) ceramic washers are used.In the case of a piezoelectric membrane, it is advantageously a component of the polyvinylidine difluoride (PVDF) family, more particularly a PVDF derivative such as a PVDF / PDMS (PDMS: polydimethylsiloxane).

[0054] When actuator A is energized, its piezoelectric elements become polarized and deform elastically to generate a mechanical stress. In one embodiment, the elastic deformation consists of an elongation of the piezoelectric element along the longitudinal axis XX of actuator A, which is also the translational axis of valve C. In other words, actuator A elongates when energized. And when de-energized, actuator A retracts and returns to its original position.

[0055] The activation of actuator A is managed by a control unit (CU), which can be, for example, a processor, microprocessor, or CPU (Central Processing Unit) integrated into an electronic terminal (computer, PLC, etc.). For example, the control signal generated by the CU and applied to actuator A can have a voltage between 0 V and 1000 V, with a current of 2 A to 10 A. The activation frequency of actuator A (the opening / closing frequency of valve V) can reach 2000 Hz. The CU can adapt the control signal, in terms of voltage and / or current, to optimize performance in terms of speed (opening / closing time) and / or precision of valve C movement, and / or noise emitted, etc. For example, a sinusoidal control signal reduces the noise generated by the movement of valve C compared to a square wave control signal.

[0056] Actuator A is sized to move valve C a distance xs. In other words, in the open position, the distance between the first face Pf1 of plate P and the second face Cf2 of the valve is xs. This distance is advantageously between 20 µm and 150 µm. The fluid flow rate through valve V can be easily controlled by adjusting the voltage applied to actuator A, which adjusts the actuator's deformation and thus this distance xs. For example, for a displacement distance xs of approximately 80 µm, a flow rate of 10 L / min is obtained for a fluid at 5 bar, a flow rate of 15 L / min for a fluid at 10 bar, and a flow rate of 80 L / min for a fluid at 300 bar. First embodiment: figures 4a and 4b.

[0057] On the figures 4a And 4bThe valve C is located at the level of the first chamber Vh. In other words, the first chamber Vh is located on either side of the actuator A and the valve C. In yet another way, the valve C is located between the actuator A and the plate P.

[0058] The piezoelectric elements are mounted on a rod At installed along the axis XX. The piezoelectric elements can be drilled along the axis XX, allowing the rod At to be inserted. The extension or retraction of the actuator A induces a translation of the rod At along the axis XX.

[0059] In one embodiment, when actuator A is energized, it extends, causing valve C to move to the closed position. When it is de-energized, actuator A retracts and returns to its original position, with valve C then moving to the open position. In this configuration, valve V is therefore naturally open: valve C is in the open position when actuator A is de-energized. However, a reverse configuration can be considered, in which valve V is naturally closed, with valve C in the closed position when actuator A is de-energized (and extends and returns to its original position).

[0060] According to a preferred embodiment, actuator A is sized to deliver a mechanical force between 1000 N (Newtons) and 10000 N.

[0061] In one embodiment, the rod At is engaged with the valve C such that the translation of said rod causes the translation of said valve between the open and closed positions. The valve C can be secured to the rod At by press fitting, welding, screwing, or any other method suitable to those skilled in the art.

[0062] The rod At extends towards the plate P. The latter has a central orifice which acts as a guide for the rod At. This design allows the precise guidance of the translation of the valve C between the open and closed positions and ensures optimal cooperation between said valve and the plate in the closed position.

[0063] The second channels Rc are arranged in the valve C so that they open into the first chamber Vh at the level of the first face Cf1 and / or are in fluidic communication with said chamber. The first face Cf1 is hereafter referred to as the "active face" of the valve C. This active face Cf1 also has hollow sections (corresponding to the channels Rc) and solid sections bordering said hollow sections, in an arrangement that may be similar to that of the figure 9The inlet E of valve V is located upstream of the flapper C, at the level of the first chamber Vh, and the outlet S is located downstream of the plate P, at the level of a second flow chamber Ve, in fluidic communication with the first channels Rp. In this configuration, in the open position, the fluid flow through valve V is as follows: i) the fluid enters the first chamber Vh through the inlet E, ii) the fluid flows through flapper C via the second channels Rc, from the first face Cf1 to the second face Cf2, iii) the fluid flows in the gap Ze separating flapper C from plate P, iv) the fluid flows through plate P via the first channels Rp, from the first face Pf1 to the second face Pf2, v) the fluid exits valve V through the second chamber Ve and the outlet S.

[0064] When the pressurized fluid enters the first chamber Vh, it exerts a force on the active face Cf1 of the valve C, and more specifically on its solid parts. This force is directed towards the plate P, forcing the valve C towards the closed position. In the closed position, this pressure force combines with that exerted by the actuator A to press the valve against the plate P with maximum force. This significantly improves the sealing of the valve V in the closed position. Second embodiment: figures 5a and 5b.

[0065] The positioning of plate P and valve C corresponds to that of the first embodiment: plate P is located at the level of the second chamber Ve and valve C at the level of the first chamber Vh (valve C is positioned on either side of actuator A and plate P). The operation of valve V is similar to that described with reference to the first embodiment.

[0066] This second embodiment differs from the first embodiment by the cooperation of the valve C with the actuator A. The latter no longer has a central rod. It has, at one of its ends, a connecting piece Al onto which the valve C is fixed. According to one embodiment, the valve C has, at its active face Cf1, a projecting element Ct, for example in the form of a rod or tenon, adapted to be fixed onto the connecting piece Al, for example by screwing.

[0067] The valve C has, on its other face Cf2, another projecting element Cg, for example in the form of a rod or tenon, which extends towards the plate P. The latter has a central orifice that acts as a guide and in which the projecting element Cg is housed. It is therefore the interaction of this other projecting element Cg with the guide orifice of the plate P that allows the precise translation of the valve C between the open and closed positions and ensures optimal cooperation between the valve and the plate in the closed position. Third embodiment: figures 6a and 6b.

[0068] As in the first embodiment, the rod At is engaged with the valve C so that the translation of said rod causes the translation of said valve.

[0069] However, the positioning of plate P and valve C is reversed compared to the first two embodiments: valve C is located in the second chamber Ve and plate P in the first chamber Vh. The first chamber Vh is therefore now positioned on either side of actuator A and fixed plate P. In other words, plate P is now located between actuator A and valve C.

[0070] In one embodiment, when actuator A is energized, it extends, causing valve C to move to the open position. When it is de-energized, actuator A retracts and returns to its original position, with valve C moving to the closed position. In this configuration, valve V is therefore naturally closed: valve C is in the closed position when actuator A is de-energized. However, a reverse configuration is also possible, in which valve V is naturally open, with valve C in the open position when actuator A is de-energized (and retracts and returns to its original position).

[0071] The second channels Rc of the valve C open into the second chamber Ve at the level of the active face Cf1 and / or are in fluidic communication with said chamber. The inlet E is located at the level of the second chamber Ve and the outlet S is located at the level of the first chamber Vh, in fluidic communication with the first channels Rp. In this configuration, in the open position, the fluid flow through the valve V is as follows: i) the fluid enters the second chamber Ve through the inlet E, ii) the fluid flows through the valve C via the second channels Rc, from the first face Cf1 to the second face Cf2, iii) the fluid flows in the spacing zone Ze separating the valve C from the plate P, iv) the fluid flows through the plate P via the first channels Rp, from the first face Pf1 to the second face Pf2, v) the fluid exits the valve V through the first chamber Vh and the outlet S.

[0072] When the pressurized fluid enters the second chamber Ve, it exerts a force on the active face Cf1 of the valve C. This force is directed towards the plate P, forcing the valve C towards the closed position. In the closed position, this pressure force helps to press the valve against the plate P with maximum stress. This significantly improves the sealing of the valve V in the closed position. Fourth embodiment: figures 7a and 7b.

[0073] The operation of the valve V and the positioning of the plate P and the valve C correspond to those of the third embodiment: the plate P is located at the level of the first chamber Vh and the valve C at the level of the second chamber Ve (the plate P is located on either side of the actuator A and the valve C).

[0074] The interaction of the valve C with the actuator A and the plate C is essentially the same as that described in the second embodiment. The actuator A has, at one end, a connecting piece Al onto which the valve C is fixed. In one embodiment, the valve C has, on its face Cf2, a projecting element Ct, for example in the form of a rod or tenon, adapted to be fixed to the connecting piece Al, for example by screwing. This projecting element Ct passes through a central opening in the plate P, which acts as a guide.

[0075] This fourth embodiment therefore combines the advantages of the second and third embodiments.

[0076] Regardless of the embodiment, it is observed that the greater the fluid pressure, the greater the pressure stress exerted on the valve C in the closed position, thus contributing to improving the sealing of the valve V. Compared to the aforementioned Bath valve, the valve V of the invention is therefore not limited in pressure.

[0077] Furthermore, in a Bath valve, the opening / closing times are limited by the maximum operating pressure. Since the V valve of the invention is not subject to this limit, the opening / closing times can be further reduced to the order of 0.5 ms, or even less. In particular, when the valve C moves from the open position to the closed position, the pressure force exerted by the fluid on said valve tends to accelerate its movement. Thus, the higher the pressure, the shorter the closing times of valve V. The applicant has experimentally observed that for a displacement distance xs of approximately 80 µm and for a fluid at 5 bar, the opening / closing times were less than 0.5 ms (on the order of 0.3 ms). A reduction in this opening / closing time of 10% is observed at 100 bar and of 20% at 300 bar. Prestressing rod(s)

[0078] Regardless of the embodiment, actuator A is advantageously prestressed to improve the mechanical strength of the piezoelectric pillar. An axial prestress is applied to the piezoelectric pillar by compressing it.

[0079] In the first embodiment ( figure 4a , 4b ) and the third embodiment ( figures 6a , 6b ), one or more Atv screw elements are engaged with the At rod in order to apply this pre-stress to the piezoelectric pillar.

[0080] In the second embodiment ( figures 5a , 5b ) and the fourth embodiment ( figures 7a , 7bThe prestressing is generated by Tp rods placed around the periphery of the column, for example, three Tp rods placed at 120° intervals, secured with fasteners and ensuring the connection between the AI ​​component and the end of said column. It will be understood that the Tp rod(s) can be used in the first and third embodiments (in addition to or instead of the Atv fasteners) and that the Atv fastener(s) can be used in the second and fourth embodiments (in addition to or instead of the Tp rods).

[0081] As an example, the At, Tp rods are made of STUBS ®< steel, their diameter being between 1 mm and 5 mm and their length between 80 mm and 200 mm.

[0082] The prestressing rod(s) At, Tp serve a dual purpose. Firstly, they subject the piezoelectric pillar to permanent axial compression stresses, ensuring continuous contact between the stacked piezoelectric elements. Secondly, the prestressing rods At, Tp act as springs, their restoring force pulling the piezoelectric pillar back, thereby significantly increasing its retraction rate.

[0083] In the first and second embodiments, when actuator A is energized, it extends, causing valve C to move to the closed position. The extension of actuator A also causes the prestressing rods At and Tp to extend, placing them under tensile stress and tension. When actuator A is de-energized, it retracts and returns to its original position. The prestressing rods At and Tp also return to their original positions and act as a return spring on the piezoelectric pillar, accelerating the movement of valve C to the open position.Due to the configuration of the prestressing rods At, Tp, the restoring force they exert (corresponding to the tensile stress to which they are subjected) allows the valve C to open more quickly, this force helping to counteract the pressure exerted on the active face Cf1 of said valve when it moves from the closed position to the open position.

[0084] In the third and fourth embodiments, the restoring force exerted by the prestressing rods At, Tp acts in the direction of the movement of the valve C towards the closed position, thereby accelerating this movement. The restoring force exerted by the prestressing rods At, Tp thus allows the valve C to close more quickly, this force combining with the pressure exerted on the active face Cf1 of said valve during the closing phase.

[0085] The At, Tp prestressing rods thus allow for a further reduction in valve opening / closing times, particularly when fluid pressure is high. The applicant was able to observe experimentally that, compared to a non-prestressed piezoelectric pillar (for example, with the same pillar, but where the piezoelectric elements are bonded together), the At, Tp prestressing rods reduced the opening time (for the first and second embodiments) and closing time (for the third and fourth embodiments) by 20% at 100 bar and by 30% at 300 bar.

[0086] The best results in terms of opening / closing speed are obtained when the total stiffness of the At, Tp prestressing rods is between 10% and 20% of the stiffness of the piezoelectric pillar alone. In other words, the original (unprestressed) piezoelectric pillar is 5 to 10 times stiffer than the At, Tp prestressing rods. For example, the piezoelectric pillar alone has a stiffness of 96 MN / m (meganewons per meter), and the set of At, Tp rods has a stiffness of 16.5 MN / m (or 5.5 MN / m per rod, if three prestressing rods are used).

[0087] The best results in terms of opening / closing speed are also obtained when the prestressing force applied to the piezoelectric pillar is between 5% and 20% of the mechanical force delivered by the piezoelectric pillar alone. In other words, the force delivered by the original (unprestressed) piezoelectric pillar is 5 to 20 times greater than the prestressing force applied by the At, Tp prestressing rods. For example, if the piezoelectric pillar delivers a mechanical force of 10 kN (kilonewtons), the prestressing force applied by all the At, Tp rods is between 0.5 kN and 2 kN (i.e., between 0.15 and 0.7 kN per rod, if three prestressing rods are used). Use of the valve that is the subject of the invention

[0088] The V valve can be used as a simple valve, in conventional applications, notably to block or allow fluid to pass through in order to supply or not supply one or more actuators or hydraulic components.

[0089] Another aspect of the invention relates to the use of valve V in a method and system for generating electricity using a piezoelectric generator to produce electrical energy. The term "piezoelectric generator" refers to any piezoelectric material or element, or combination thereof, capable of becoming electrically polarized under mechanical stress and, conversely, of deforming when an electric field is applied. In this case, the piezoelectric material is primarily used to produce electrical energy when subjected to mechanical stress.

[0090] There Figure 10This illustrates an embodiment incorporating elements of an electricity generation system according to the invention, namely a circuit 10, or more precisely a portion of the circuit, through which a pressurized fluid (for example, between 5 bar and 300 bar) flows, and on or at the level of which is provided a fluidic cavity 3 housing a piezoelectric stack or pillar 4 forming the piezoelectric generator. This pillar 4 is connected to an electronic charge extraction circuit 5. The cavity 3 is installed between two valves according to the invention, respectively an inlet valve V1 and an exhaust valve V2, which valves are mounted in series.

[0091] Conduit 10 may, for example, consist of a branch made on a pressurized fluid pipeline of a wind turbine, tidal turbine, wave energy, etc. type installation.

[0092] In the first sequence, the intake valve V1 is actuated so that its flap is in the open position and the exhaust valve V2 is actuated so that its flap is in the closed position. The pressurized fluid circulating in the circuit 10 enters and at least partially fills the fluidic cavity 3, thereby generating mechanical pressure on the piezoelectric pillar 4. This pressure causes the pillar 4 to deform, generating electrical charges, also referred to as electrical energy, which are recovered by the electronic charge extraction circuit 5.

[0093] Following this initial operating sequence, a second operating sequence involves the closure of the inlet valve V1 and the opening of the exhaust valve V2. The fluid escapes from the fluidic cavity 3, so that the pillar 4 is no longer constrained and returns to its initial resting state (without pressure exerted by the fluid). The reverse deformation, causing the piezoelectric generator 4 to return to its initial state, allows the generation of electrical charges again, which can be recovered by the electronic charge recovery circuit 5. Thus, the system recovers electrical energy both during the entry of the pressurized fluid into the fluidic cavity 3 and during the evacuation of said fluid from the cavity.

[0094] Thus, when comparing the first and second sequences, the intake valves V1 and exhaust valves V2 exhibit opposite or inversely related open / closed positions. In other words, when one—for example, the intake valve V1—is open, the other valve V2 is closed, and the two sequences are advantageously closely linked to each other within the framework of the present invention. The invention is characterized, in such a specific system, by the alternation of the aforementioned first and second sequences. Furthermore, the frequency of occurrence of the first and / or second sequences is modifiable or adaptable according to various parameters, including, in particular, the resonance frequency of the piezoelectric generator 4, which resonance frequency is itself modifiable by changing the stiffness of said piezoelectric generator.

[0095] According to an embodiment that simplifies the design, valves V1 and V2 are identical. For example, they are designed according to the first embodiment ( figures 4a And 4b ) or according to the second method ( figures 5a , 5b ) or according to the third mode ( figures 6a , 6b ) or according to the fourth mode ( figures 7a , 7b ).

[0096] In one variant, valves V1 and V2 are separate. In particular, they are designed according to two distinct embodiments. Advantageously, the intake valve V1 is designed according to the first embodiment ( figures 4a And 4b ) or according to the second method ( figures 5a , 5b ), and the V2 exhaust valve according to the third mode ( figures 6a , 6b ) or according to the fourth mode ( figures 7a , 7bThe fluid passing through valves V1 and V2 exhibits a certain degree of compressibility, even if slight in the case of a liquid. Therefore, a relative change in its volume can be observed as it flows under pressure between the two valves V1 and V2 and enters the fluidic cavity 3. This volume change induces a loss of power. It is therefore preferable for this volume change to be as small as possible to minimize the power loss. However, the volume of the first chamber Vh can differ from that of the second chamber Ve. In practice, the volume of the first chamber Vh is greater than that of the second chamber Ve. During the first operating sequence mentioned above (intake valve V1 open and exhaust valve V2 closed), it is advantageous for the fluid to enter the chamber of the exhaust valve V2 with the smaller volume, that is, the second chamber Ve.This is why the V2 exhaust valve is advantageously according to the third mode (. figures 6a , 6b ) or according to the fourth mode ( figures 7a , 7b ).

[0097] It should be noted that the fluidic cavity 3 has a variable volume due to the contraction of the piezoelectric generator 4 when the fluid enters said cavity and the expansion of said generator when said fluid exits said cavity. The variation in the volume of the fluidic cavity 3 can be adjusted, in particular by adjusting the stiffness of the piezoelectric generator 4. This variation in the volume of the fluidic cavity 3 has a direct effect on the flow rate of the liquid circulating in the conduit 10 and therefore on the torque of the pump 11.

[0098] In one embodiment, the piezoelectric pillar 4 consists of a stack of piezoelectric ceramics alternating with electrodes made of a conductive material, such as copper or bronze. For example, PZT hard ceramic discs are used. The electrodes are connected in parallel or in series. The number of ceramics and electrodes varies from 2 to 50, or even 150. These ceramics and electrodes have the same shape and preferably a circular cross-section. They are axially drilled. For example, their external diameter is between 0.5 cm and 20 cm, and their thickness is between 1 mm and 100 mm. The diameter of the axial drilling is, for example, between 0.5 cm and 10 cm. The axial drilling ensures axial alignment of the ceramics and electrodes. When the ceramics and electrodes are stacked, the axial holes define a central bore coaxial with the axis of pillar 4.This central bore allows the passage of a rod that ensures centering, alignment, and helps to hold the ceramics and electrodes in place. Fastening devices are located at the ends of the rod. These fasteners may be rigid pieces attached to the ends of the rod to clamp the stack of ceramics and electrodes. For example, the piece may be a nut screwed onto the threaded end of the rod. Alternatively, the piece may be a nut, or a threaded part, fixed to a frame, into which the other threaded end of the rod is screwed. For safety reasons, the stack of ceramics and electrodes is advantageously electrically insulated. To achieve this, the rod may be placed in a sleeve or sheath made of an electrically insulating material such as plastic.It is also possible to house the stack in a sleeve or in an outer sheath also made of an electrically insulating material.

[0099] The electronic charge extraction circuit 5 recovers electrical energy—the released electrons—from the piezoelectric generator 4. In one embodiment, it comprises: a high-voltage controlled switch, advantageously a thyristor; a voltage rectifier bridge; an inductor whose connection to the piezoelectric generator 4 forms a resonant LC circuit, the capacitive element being the pillar itself, a filter capacitor, or a filter capacitor connected in parallel; and a storage system for storing this electrical energy before it is processed for use on a grid. This storage system consists, for example, of a battery or a bank of supercapacitors.

[0100] When the piezoelectric generator 4 is subjected to alternating excitation (according to the sequences described previously), and during the increasing stress phase, the switch is held open. The piezoelectric generator 4 is in an open circuit, and electrical charges accumulate across the pillar, which acts as a capacitor. When the mechanical stress applied to the piezoelectric generator 4 is at its maximum, the switch is briefly closed for a duration corresponding to half a period of the LC circuit's resonance. Thus, all the electrical charges accumulated across the piezoelectric generator 4 are extracted from the pillar by the circuit 5. During the decreasing stress phase, the piezoelectric generator 4 recharges.When the stress is minimal, the switch is briefly closed again for a duration corresponding to half a period of the LC circuit's resonance, in order to extract the electrical charges. Then the cycle resumes with the alternation of the first and second sequences.

[0101] The configuration of the electronic charge extraction circuit 5 is adapted to maximize the electrical energy produced by the piezoelectric generator 4. This configuration makes it possible to double the electrical energy generated by the piezoelectric generator 4 by recovering it a first time when the generator is put under stress by the pressurized fluid (first sequence described above), and a second time when it is released (second sequence described above).

[0102] In one embodiment, the opening / closing frequency of valves V1 and V2, i.e., the frequency of the first or second sequence, is controlled by their respective control units UC1 and UC2, so that this opening / closing frequency, or of the first or second sequence, corresponds to the resonant frequency of the piezoelectric generator 4 in order to recover a maximum of electrical energy. Such optimal operation, in which the recovery of charge or electrical energy is maximized, is obviously possible with all embodiments. In another embodiment, a single control unit UC1 or UC2 is used to control the opening / closing frequency of valves V1 and V2.

[0103] The resonant frequency of the piezoelectric generator 4 is between 10 Hz and 1000 Hz. The use of the ultra-fast valves V1, V2 according to the invention makes it easy to ensure excitation frequencies above 100 Hz and up to 1000 Hz.

[0104] There figure 11 This illustrates an alternative embodiment where several fluidic cavities 3a, 3b are installed in the conduit 10, between valves V1 and V2. This embodiment allows for the recovery of more electrical energy. Each fluidic cavity 3 houses a piezoelectric generator 4a, 4b. These generators 4a, 4b are here connected to a common charge extraction electronic circuit 5, but it is possible to connect each generator to its own charge extraction electronic circuit.

[0105] The electricity generation system just described is particularly simple, reliable, and robust in design and can be easily integrated into any type of installation with a pressurized fluid circuit, given its ease of implementation. Furthermore, this system is relatively inexpensive, both in terms of assembly / installation and / or manufacturing, and in terms of the individual components that make up such a system.

[0106] The arrangement of the various elements and / or means and / or steps of the invention, in the embodiments described above, should not be understood as requiring such an arrangement in all implementations. In any event, it will be understood that various modifications may be made to these elements and / or means and / or steps without departing from the spirit and scope of the invention. In particular: The plate P and / or the valve C may have a cross-section other than circular, for example, a square, rectangular, polygonal, oval, etc. The first channels Rp may be in the form of segments of annular grooves, or solely in the form of through holes, or in other forms such as non-annular and / or non-concentric grooves or segments of grooves. The annular grooves Rp may be through grooves, i.e., formed through the entire thickness of the plate P and opening at each of the faces Pf1 and Pf2. The second channels Rc may be in the same form as the first channels Rp (grooves + holes), or solely in the form of through holes, or in other forms such as non-annular and / or non-concentric grooves or segments of grooves.The piezoelectric generator 4 can be in the form of a piezoelectric membrane, for example made of a material from the PVDF family, more particularly a PVDF derivative such as PVDF / PDMS.

[0107] Furthermore, one or more features described only in one embodiment can be combined with one or more other features described only in another embodiment. Similarly, one or more features described only in one embodiment can be generalized to other embodiments, even if that feature or those features are described only in combination with other features.

[0108] The use of the verb "comporter", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

Claims

1. Valve comprising a pressurised fluid inlet (E) and a fluid outlet (S), said valve (V) comprising: - a fixed plate (P) wherein first fluid flow channels (Rp) are formed, - a shutter (C) wherein second fluid flow channels (Rc) are formed, said shutter being movably mounted between: ∘ an open position wherein the first channels (Rp) and the second channels (Rc) are in a configuration allowing the flow of the fluid between the inlet (E) and the outlet (S), ∘ a closed position wherein the first channels (Rp) and the second channels (Rc) are in a configuration blocking the flow of the fluid between the inlet (E) and the outlet (S), - a piezoelectric actuator (A) acting on the shutter (C) to move it between the closed position and the open position, which actuator consists of a piezoelectric pillar formed by a stacking structure of piezoelectric elements, which pillar extends when the actuator is powered and retracts when said actuator is not powered, the inlet (E) being arranged such that, in use, the pressurised fluid exerts a pressure force on an active face (Cf1) of said shutter forcing said shutter towards the closed position, characterised in that the actuator (A) is axially prestressed by means of one or more prestressing rods (At, Tp) forming spring elements in which the restoring force acts in the direction of retraction of the piezoelectric pillar.

2. Valve according to claim 1, wherein the prestress force applied by the prestressing rod(s) (At, Tp) on the piezoelectric pillar is between 5% and 20% of the mechanical force delivered by said piezoelectric pillar alone.

3. Valve according to any one of claims 1 or 2, wherein the prestressing rod(s) (At, Tp) have a rigidity between 10% and 20% of the rigidity of the piezoelectric pillar alone.

4. Valve according to any one of the preceding claims, wherein: - in the open position, the shutter (C) is spaced apart from the plate (P) in such a way that the first channels (Rp) and the second channels (Rc) are in fluidic communication, - in the closed position, the shutter (C) is in contact with the plate (P) in such a way that the first channels (Rp) and the second channels (Rc) are not in fluid communication.

5. Valve according to any one of the preceding claims, wherein: - the shutter (C) is movably mounted in a chamber (Vh, Ve) between the open position and the closed position, - the second channels (Rc) are in fluidic communication with the chamber (Vh, ve), - the inlet (E) is disposed upstream of the shutter (C), in the vicinity of the chamber (Vh, Ve), - the outlet (S) is disposed downstream of the plate (P), in fluidic communication with the first channels (Rp), in such a way that, in use and in the open position, the fluid flows from the second channels (Rc) to said first channels.

6. Valve according to any one of claims 1 to 5, wherein the piezoelectric actuator (A) is configured in such a way that the shutter (C) is naturally in the open position when said actuator is not powered, the prestressing rod(s) (At, Tp) being configured in such a way that the restoring force exerted by said rod(s) acts against the pressure force exerted, in use, on the active face (Cf1) of said shutter when said shutter switches from the closed position to the open position.

7. Valve according to claim 6, wherein the shutter (C) is disposed between the actuator (A) and the plate (P).

8. Valve according to any one of claims 1 to 5, wherein the piezoelectric actuator (A) is configured in such a way that the shutter (C) is naturally in the closed position when said actuator is not powered, the prestressing rod(s) (At, Tp) being configured in such a way that the restoring force exerted by said rod(s) is combined with the pressure force exerted, in use, on the active face (Cf1) of said shutter when said shutter switches from the open position to the closed position.

9. Valve according to claim 8, wherein the plate (P) is disposed between the actuator (A) and the shutter (C).

10. Valve according to any one of claims 1 to 9, wherein: - the piezoelectric elements are mounted on a prestressing rod (At) installed along a translational axis (X-X), - the rod (At) is engaged with the shutter (C) in such a way that the translation of said rod induced by the piezoelectric actuator (A) entails the translation of said shutter between the open and closed positions.

11. Valve according to claim 10, wherein the plate (P) has a central orifice wherein the rod (At) is housed, said orifice acting as a guide for said rod.

12. Valve according to any one of claims 1 to 9, wherein: - the piezoelectric actuator (A) has, in the vicinity of one of its ends, a connecting part (Al) to which the shutter (C) is attached, - the shutter (C) comprises, in the vicinity of one face, a projecting element (Ct) adapted to be attached to the connecting part (Al).

13. Valve according to claim 12 taken in conjunction with claim 9, wherein: - the shutter (C) comprises, in the vicinity of another face, another projecting element (Cg) extending towards the plate (P), - the plate (P) has a central orifice wherein said other projecting element (Cg) is housed, said orifice acting as a guide for said other projecting element (Cg).

14. Electricity-generating system comprising: - a circuit (10) wherein a pressurised fluid circulates, - at least one fluidic cavity (3) formed on at least one portion of the circuit (10), said cavity housing a piezoelectric generator (4) connected to an electronic load extraction circuit (5) capable of recovering the electrical energy from said piezoelectric generator (4), and wherein: - the fluidic cavity (3) is installed between two valves according to any one of claims 1 to 13, respectively an inflow valve (V1) and a relief valve (V2), - in a first operating sequence, the inflow valve (V1) is controlled so that its shutter is in the open position, and the relief valve (V2) is controlled so that its shutter is in the closed position, in such a way that the pressurised fluid enters and fills at least partially the fluidic cavity (3) so as to induce a mechanical pressure on the piezoelectric generator (4), said pressure producing a deformation of said generator generating an electrical energy recovered by the electronic load extraction circuit (5), - in a second operating sequence, the inflow valve (V1) is controlled so that its shutter is in the closed position, and the relief valve (V2) is controlled so that its shutter is in the open position, in such a way that the pressurised fluid is discharged from the fluidic cavity (3) and the piezoelectric generator (4) is no longer stressed.

15. System according to claim 14, wherein the open / closed frequency of the inflow (V1) and relief (V2) valves is controlled in such a way that it corresponds to the resonance frequency of the piezoelectric generator (4).

16. System according to any one of claims 14 or 15, wherein the inflow valve (V1) is according to claim 7 and the relief valve (V2) is according to claim 9.

17. Process for accelerating the opening / closing of a valve, said valve comprising a pressurised fluid inlet (E) and a fluid outlet (S), and comprising: - a fixed plate (P) wherein first fluid flow channels (Rp) are formed, - a shutter (C) wherein second fluid flow channels (Rc) are formed, said shutter being movably mounted between: ∘ an open position wherein the first channels (Rp) and the second channels (Rc) are in a configuration allowing the flow of the fluid between the inlet (E) and the outlet (S), ∘ a closed position wherein the first channels (Rp) and the second channels (Rc) are in a configuration blocking the flow of the fluid between the inlet (E) and the outlet (S), - a piezoelectric actuator (A) acting on the shutter (C) to move it between the closed position and the open position, which actuator consists of a piezoelectric pillar formed by a stacking structure of piezoelectric elements, which pillar extends when said actuator is powered and retracts when said actuator is not powered, said process comprising the steps of : - arranging the inlet (E) in such a way that, in use, the pressurised fluid exerts a pressure force on an active face (Cf1) of the shutter (C) stressing said shutter to the closed position, - axially prestressing the actuator (A) by means of one or more prestressing rods (At, Tp) forming spring elements in which the restoring force acts in the direction of retraction of the piezoelectric pillar.