System for combating colonisation, by aquatic molluscs, of a facility submerged in water

Abstract

The invention relates to a system (100) for combating colonisation, by aquatic molluscs, of a facility submerged in water, the system comprising a cylindrical portion (150) having an opening (151, 102) which allows the ingress or egress of water, and comprising a first ultrasonic barrier including at least one first ultrasonic wave-emitting element (170) which is capable of covering a first segment of the cylindrical portion and of emitting ultrasonic waves in the aquatic medium such that the ultrasonic waves make it possible to create cavitation facing a region of the surface of the cylindrical portion. The invention also relates to a use in a suction strainer (103), which is intended to be submerged in water, for a water pumping system of a drinking water or industrial water facility or of a thermal network facility having a heat exchanger. The invention also relates to a use in a facility comprising a pumping system having a portion submerged in water.

Description

System for combating colonization by aquatic molluscs of an installation submerged in water Technical field

[0001] La présente invention concerne un système de lutte contre la Colonization of a submerged facility by aquatic mollusks. This system includes an ultrasonic barrier or multiple ultrasonic barriers preventing colonization of the facility, and possibly a geometric or physical barrier. These barriers block the expansion of colonization by blocking the paths allowing mollusks to spread to an area of ​​the facility that has not yet been colonized.

[0002] Ce système peut être monté, par exemple, sur une crépine d’aspiration for a drinking or industrial water installation or for a thermal network system using lake water as an energy source, including a water pumping system.

[0003] Descriptif et fonctionnement d’un système de pompage pour alimentera drinking water network: A pumping system is composed of a suction strainer, a suction pipe, a pumping element as well as a filtration and disinfection system in different stages. This assembly is then connected to the network to be supplied. When the system is in operation, water is sucked through the strainer and the suction pipe by starting the pumping system. The suction strainer is essentially formed by a coarse filter element mounted at the end of a pumping pipe. This prevents coarse foreign bodies from being sucked in and risking clogging or damaging the suction pipe or the pumping-filtration system. It is a generally spherical or cylindrical part, hollowed out and pierced with holes, used to stop foreign bodies at the opening of a suction pipe. The pipe carries water from the strainer to the pumping and filtration part of the installation.The pumping-filtration part carries out the movement of the water as well as a fine filtration in order to make the water clean and to be able to distribute it in a water network through the distributor. A system such as this one makes it possible to pump water from lakes, dams, reservoirs, seas, oceans, etc.… in order to make it usable for an urban water network, industrial, cooling, heating, swimming pool, irrigation etc… MROTE-4-PCT.

[0004] Descriptif et fonctionnement d’un système de pompage pour alimenter a thermal network system: The pumping part of this type of installation works in the same way and with the same elements submerged in the lake as that used to supply an urban water network. The filtration system is less complex than that used to produce drinking water but must be sufficiently efficient to protect the installation's heat exchanger. Once the water has passed through the heat exchanger, it is redirected to the lake.

[0005] Autre exemple d’installation immergée : échangeur thermiquedirectly submerged in a lake. This variant does not include a suction strainer circulating the pumped water in an exchanger after the pump. For this one, the exchanger is submerged in the water and directly carries out the heat exchange between the lake water and a heat transfer fluid. The element subject to the problem of colonization by aquatic molluscs is therefore the submerged exchanger.

[0006] Les systèmes de pompages d’eau installés dans certains lacs sont, depuisa few years, colonized by new species of aquatic mollusks. Indeed, these mollusks proliferate in the bottom of aquatic environments by clinging to any substrate that allows them to develop. Pumping installations are therefore also targeted and gradually find themselves covered with these individuals. This colonization results in progressively blocking the suction strainers as well as reducing the internal passage sections of the suction pipes. This therefore results in an increase in pressure losses in the hydraulic system leading to a reduction in water flow and an increase in energy consumption by the pumping installation. Among these aquatic mollusks, we note in particular bivalve aquatic mollusks such as the following two species: quagga mussels (Dreissena burgensis) and zebra mussels (Dreissena polymorpha). State of the art

[0007] Jusqu’à présent, les installations concernées par cette problématiqueare mechanically cleaned to remove molluscs that may have colonized the suction strainers and the inside of the suction pipes. To carry out the cleaning, the strainers are generally dismantled and then cleaned with high-pressure water jet systems. The pipes are cleaned with the same water jet system or with a cleaning system carried out using MROTE-4-PCT of a cannonball or shell scraping the internal surfaces of the pipes in order to detach the mollusks.

[0008] Ces étapes de nettoyage permettent de résoudre momentanément leproblem but will have to be repeated tirelessly when the mollusks have colonized the pumping installations again. In addition, it is necessary to shut down the installations in order to clean them. The costs incurred are also a major negative point of this solution. Indeed, the suction strainers are generally installed at several tens of meters deep and therefore require specialized divers and often significant technical resources to carry out dismantling and cleaning.

[0009] Une autre solution utilisée jusqu’à présent afin d’éviter la colonisationThe main method of controlling the spread of Quagga mussels in the water supply system is to chlorinate the water in the pipes and at the strainers. This method is the most effective and safest way to control the spread of Quagga mussels in the water supply system. In drinking water, the chlorine concentration is usually very low and is not a health concern. The risk is long-term, such as cancer due to prolonged exposure to chlorinated water. This is mainly due to trihalomethanes and other disinfection by-products. Trihalomethanes are carcinogenic and can also cause rectal cancer. Health Canada says this is not enough to justify discontinuation. In Europe, however, chlorination has been discontinued in many communities.

[0010] Le processus de colonisation des mollusques aquatiques est le suivant:- The veliger larvae (drifting planktonic stage) develop and look for a substrate to attach to. These larvae drift in the water flow and are therefore unable to swim to choose their development location. In a water suction system, they cannot attach to an element of the pumping system and develop there. The suction flow of 1 [m / s] is too fast for them to find a point of attachment.- Mussels from the pedivegilar stage produce a byssus (see Figure 1). The byssus allows the individual to attach to a support but does not prevent it from moving. The animal can, if necessary, quickly regenerate it by producing new filaments from the byssal gland. We sometimes wrongly speak of swimming when the adult animal is detached, and this may be linked to the relative buoyancy of certain individuals.In terms of swimming, the mussel can "crawl" on its foot and / or push off a substrate with its foot (or on the contrary anchor itself to it) in order to move. In the laboratory, 20 to 30 [cm] can be covered by crawling in about twenty hours (Peyer et al., 2011) but this depends a lot on the conditions. MROTE-4-PCT Greater distances have already been observed in zebras, whose movements have been studied much more extensively (Kobak, 2014). Photographic monitoring allowed D'Hont et al. (2021b) to assess in the laboratory that movements over 24 hours last a total of 65 min on average, with a speed of 28 cm / h and an average distance traveled of 29 cm. The maximum speeds of the quagga (90 cm / h) are much greater than the maximum values ​​in zebras (60 cm / h). In comparable controlled situations, a 10% greater number of quaggas in mobility is observed than in zebras (D'Hont et al., 2021b).

[0011] Le byssus n’exclut pas que l’individu puisse se détacher, sous l’influenceof different stimuli, to reattach elsewhere. Light, hypoxia and odors of injured conspecifics, for example, cause detachment under controlled conditions, while temperature, water movement, predator odors or the good health of conspecifics stimulate stronger adhesion (by increasing the number of byssus filaments). Detachment is 40% greater in an isolated individual than in an individual within a colony in the zebra. Figure 2 illustrates these behaviors, namely: - in the presence of healthy conspecifics, the mussels attach more strongly to the substrate and the mussels detach and move less often, - in the presence of unwell conspecifics, the mussels attach less strongly to the substrate and the mussels detach and move over shorter distances.

[0012] Sur la figure 3, on a représenté les différents stades de croissance d’unA bivalve aquatic mollusk such as a quagga mussel from the embryonic stage to the juvenile stage. The pediveliger growth stage is the growth stage during which individuals stop floating in the water and begin to precipitate in order to attach themselves to a substrate. From the next stage, called "postlarva", the behavior of a quagga mussel corresponds to that described above in relation to Figure 2.

[0013] Ces différents éléments nous permettent de comprendre que les Aquatic mollusks tend to attach themselves close to each other and can detach and move according to the evolution of their living environment.

[0014] Dans le cadre de la présente invention, il a pu être observé que laMussel colonization tended to progress head-on on a substrate (imagine it as lava advancing on a floor). This observation could be observed directly on the outer walls of a pipe and a suction strainer. Video images of the interior of a pipe also allowed us to observe the progress of colonization in this form. The mussels MROTE-4-PCT advance on the exterior (interior) surfaces, which leaves a visible furrow in the organic deposits previously present on the colonized surfaces.

[0015] Avec ces différentes constatations, il apparait plausible qu’en plaçant un element on an aquatic bottom colonized by molluscs, this will in turn be colonized by the movement of molluscs from the aquatic bottom to this element. The young individuals will also seek to establish themselves on this new substrate close to other older congeners having begun to establish themselves on it. Brief summary of the invention

[0016] Un but de la présente invention est de proposer un dispositif ou unsystem creating an environment inhospitable to colonization by aquatic molluscs.

[0017] Un autre but de l’invention est de proposer un dispositif ou un système protecting any submerged installation or submerged portion of an installation from colonization by aquatic molluscs.

[0018] Un autre but de l’invention est de proposer un dispositif ou un système adaptable to suction strainers, submerged exchangers or any other submerged part or installation allowing the entry or exit of water, in particular but not exclusively a part or installation stopping dirt and foreign bodies at the opening of a pipe, conduit or tank.

[0019] Selon l’invention, ces buts sont atteints notamment au moyen d’unsystem for combating colonization by aquatic molluscs of an installation submerged in water comprising a cylindrical portion with an opening allowing the entry or exit of water, comprising a first ultrasonic barrier comprising at least one first ultrasonic wave emitting element capable of covering a first section of said cylindrical portion, and of emitting ultrasonic waves into the aquatic environment, so that said ultrasonic waves allow the creation of cavitation opposite an area of ​​the surface of the cylindrical portion.

[0020] On comprend que l’environnement inhospitalier prévenant la Colonization by aquatic molluscs is created at least in part by ultrasound from the ultrasonic barrier and which propagate in the aquatic environment surrounding the portion of the installation to be protected from colonization. MROTE-4-PCT

[0021] Ainsi, si la zone de la surface de la portion cylindrique qui se voitcovered by a volume of water with cavitation corresponds to a path towards the opening, the progression of colonization by aquatic molluscs of the submerged installation is prevented at the location of this zone. Thanks to the transmission of ultrasonic waves in water, we understand that the area of ​​the surface of the cylindrical portion opposite which cavitation exists, is not limited to the section of the cylindrical portion covered by the ultrasonic barrier, but goes beyond. In this context, the delimitation of this zone covered by cavitation, and therefore protected from any presence and colonization of molluscs, depends on the orientation of emission of the waves and therefore on the element(s) emitting ultrasonic waves.

[0022] Dans le présent texte, on entend par « tronçon » de la portioncylindrical with opening any part of the cylindrical portion, regardless of the location, shape and extent of the part of the cylindrical portion to be considered. As will be seen from the following description and the exemplary embodiments presented, different arrangements are possible within the framework of the present invention, for which the ultrasonic barrier(s) cover(s) different parts of the cylindrical portion.

[0023] Aussi, lorsqu’il est indiqué qu’il s’agit d’un élément émetteur d’ondes ultrasonic wave emitter capable of covering a section of said cylindrical portion, the term "cover" designates a respective face-to-face position, in contact or not (at a distance), between said ultrasonic wave emitter and the section of said cylindrical portion. If the ultrasonic wave emitter element is not in contact with the cylindrical portion, the distance which separates them is preferably less than 30 cm, and preferably less than 10 cm.

[0024] Également, dans le cadre de la présente invention, la portion cylindriquewith opening on which the ultrasonic barrier(s) is(are) applied corresponds to different possibilities, whether for the shape of the section of the cylindrical portion, for the size of the cylindrical portion or even the location, size or number of openings allowing the entry or exit of water.

[0025] Selon le mode de réalisation, ledit premier élément émetteur d’ondes ultrasonic is capable of emitting ultrasonic waves in the opposite direction to MROTE-4-PCT said opening or in the direction of said opening, or both in the direction of said opening and in the direction opposite to said opening.

[0026] Cette zone de la surface de la portion cylindrique, en regard de laquelle cavitation exists, may be adjacent to said first section of the cylindrical portion.

[0027] La présente invention présente notamment l’avantage de ne pasgenerate vibrations of the structure of the installation to be protected from colonization, which does not damage said structure. Indeed, in the case of the present invention, only ultrasonic generating transducers are used which are independent of the structure of the installation to be protected and not such transducers directly fixed to the structure or associated with vibrating sonotrodes which would transmit the waves in the form of vibrations of the parts of the structure of the installation. These ultrasonic generating transducers emit waves at a frequency of, for example, between 20 and 70 KHz, preferably between 20 and 40 KHz. For example, they are low-frequency ultrasonic generating transducers of the piezoelectric type comprising superimposed layers of piezoelectric material (generally ceramic such as PZT) and metallic material forming an electrode.A vibration amplitude of a few micrometers is obtained on the active face of these ultrasonic generating transducers. In the present case, good results have been observed with cavitation in water for a vibration amplitude of the order of 3 to 5 micrometers from the active face of the ultrasonic generating transducers. Advantageously, the ultrasonic generating transducers are not in contact with the cylindrical portion. As will be seen, the ultrasonic generating transducers are at a distance from the cylindrical portion. For example, the ultrasonic generating transducers are fixed by their active face, which emits the ultrasound, on the emission wall of a sealed metal box. In this case, this emission wall of the metal box is not in contact with the cylindrical portion: it can be at a distance and / or oriented in a direction other than the direction directed towards the cylindrical portion.

[0028] La présente invention réalise ainsi un dispositif vibratoire anti-colonization by aquatic molluscs, such as quagga mussels, ultrasound formation of the aquatic environment and formation of cavitation in relation to the area to be protected from colonization. MROTE-4-PCT

[0029] D’autres dispositions possibles, seules ou en combinaison sont présentées in claims 2 and following.

[0030] Selon une disposition possible, ledit premier élément émetteur d’ondes ultrasonic emits ultrasonic waves through an emission face that is not in contact with the cylindrical portion. This emission face may be at a distance and / or oriented in a direction other than the direction directed towards the cylindrical portion.

[0031] Ainsi, selon une autre disposition, le système selon l’invention comprendfurthermore a second ultrasonic barrier comprising a second ultrasonic wave emitting element capable of covering a second section of said cylindrical portion and a third ultrasonic wave emitting element capable of covering a third section of said cylindrical portion, said second section and said third section being located on either side of said opening, said second and third ultrasonic wave emitting elements being capable of emitting ultrasonic waves into the aquatic environment in the direction of said opening, so that said ultrasonic waves allow the creation of cavitation in an area opposite said opening. Thus, this area opposite said opening is also protected from colonization by aquatic molluscs.

[0032] Selon une autre disposition, le système selon l’invention comprend enin addition to a third ultrasonic barrier comprising a set of at least two ultrasonic wave emitting elements, capable of being arranged on the end of the cylindrical portion, the ultrasonic wave emitters of this set being arranged one near or next to the other, and being capable of emitting ultrasonic waves into the aquatic environment in opposite directions relative to each other. For example, two ultrasonic wave emitting elements may be used forming a pair, the two ultrasonic wave emitting elements of which are elongated and arranged parallel to each other, in particular at a diameter if the cylindrical portion has a circular section. Three or more ultrasonic wave emitting elements may also be used, for example arranged in a star shape.It is understood that this third ultrasonic barrier creates another area not conducive to the installation or arrival of aquatic molluscs at the location of the end of the cylindrical portion. MROTE-4-PCT

[0033] Selon une disposition possible, chaque élément émetteur d’ondes ultrasonic is capable of emitting waves at a frequency between 20 and 70 KHz, preferably between 20 and 40 KHz.

[0034] Selon une autre disposition possible, chaque élément émetteur d’ondesultrasonic (the first and, where appropriate, the second and third) comprises a metal box capable of covering the section of said cylindrical portion, ultrasonic wave generating transducers fixed on one of the walls of the metal box in order to generate the ultrasonic waves from said wall forming an emission wall and a set of electric cables to power the ultrasonic wave generating transducers. We can take ultrasonic wave generating transducers which have a power greater than or equal to 0.5 W / cm2. This is the power in Watts per unit of surface (in cm 2 ) of the active face of the ultrasonic generator transducers. A power between 1.5 and 3 W / cm2 gives good cavitation results.

[0035] Dans ce cas, chaque caisson métallique peut être étanche.it is then possible to provide in the system according to the invention a pressurization circuit connected to each metal box by a pressurized air supply pipe and making it possible to generate in the box an air pressure of a value equal to the pressure value of the water at the immersion location of said system for combating colonization by aquatic molluscs. This pressurization circuit comprises for example an air supply pipe opening into each metal box or an air supply pipe opening into a box, associated with connecting pipes between the metal boxes. In all these cases, all the metal boxes can be under air pressure during the emission of ultrasonic waves by the ultrasonic wave emitting elements.Such an arrangement guarantees the good propagation of ultrasonic waves through the wall of the metal boxes and beyond, into the water located in the propagation space opposite the active face of the ultrasonic transducers.

[0036] Selon une autre disposition possible, le système selon l’invention further comprises a physical or geometric barrier comprising a radial wall in the form of a collar, located at a distance from the first ultrasonic barrier, on the side of the first ultrasonic barrier from which the ultrasonic waves are emitted. It will be seen in the detailed description that this material obstacle also blocks the advance of aquatic molluscs. MROTE-4-PCT

[0037] L’invention concerne également une crépine d’aspiration destinée à êtreimmersed in water, for a water pumping system of a drinking or industrial water installation or a thermal network installation with heat exchanger, said suction strainer comprising a frame with a first tubular end intended to be connected to the inlet of a suction pipe and a cylindrical portion with an opening, and a system for combating colonization by aquatic molluscs as described in the present text, this system covering said cylindrical portion, and being configured so that the ultrasonic waves cover said cylindrical portion, including the opening. Said opening can be entirely covered by a filter.

[0038] L’invention concerne également un échangeur thermique destiné à êtreimmersed in water, comprising at least one mouthpiece for sucking water towards an opening, said mouthpiece forming a cylindrical portion with an opening and being equipped with a system for combating colonization by aquatic molluscs as described in the present text. Said opening may be entirely covered by a filter. Said system is configured so that the ultrasonic waves cover said cylindrical portion, including the opening.

[0039] D’une manière générale, l’invention concerne une installationcomprising a pumping system with a part submerged in water comprising a cylindrical portion with an opening allowing the entry of water, said cylindrical portion being equipped and covered with a system for combating colonization by aquatic molluscs as described in the present text. Said opening can be entirely covered by a filter. Said system is configured so that the ultrasonic waves cover said cylindrical portion, including the opening. Brief description of the figures

[0040] Des exemples de mise en œuvre de l’invention sont indiqués dans ladescription illustrated by the appended figures in which:- Figure 1 illustrates the attachment of a mussel to a substrate;- Figure 2 illustrates the behavior of mussels during the mussel colonization process;- Figure 3 illustrates the different growth stages of a quagga mussel from the embryonic stage to the juvenile stage;- Figures 4 and 5 illustrate, in perspective side view, respectively assembled and exploded, an assembly comprising a strainer with a system according to the invention;- Figure 6 represents, in perspective, a partial view of an ultrasound emitting element that can be used in the context of the present invention,- Figure 7 illustrates a detail of Figure 4 after enlargement,- Figures 8 and 9 illustrate, on the assembly of Figures 4 and 5, the zone Z1 that can be colonized, the zone Z2 of possible end of colonization and the zone Z3 not colonized by aquatic molluscs,-Figures 10 to 12 represent examples of electrical assembly of a system according to the present invention, with air pressurization of the boxes in the case of Figures 11 and 12, -Figures 13A and 13B illustrate in perspective an ultrasonic emitting element in the shape of an arc of a circle, Figure 13B being a cutaway view with a part of the box open allowing to see the series of ultrasonic transducers and their active face in contact with the emission face of the wall of the metal box, -Figures 14A and 14B are views similar to those of Figures 13A and 13B, illustrating in perspective a variant of an ultrasonic emitting element in the shape of an arc of a circle comprising two series of superimposed ultrasonic transducers emitting in two opposite directions, -Figure 15 is a perspective view of an annular module comprising the different elements to be mounted on a cylindrical portion of an installation to be protected aquatic molluscs,- Figure 16 shows an exploded view of the module of Figure 15, - Figure 17 is a detail showing a possible fixing system for mounting the housing of an ultrasonic emitting element on a cylindrical portion formed of a filter element, - Figure 18 shows in perspective an embodiment of a system according to the invention in which two annular modules are mounted side by side on the external face of a filter element, emitting in two opposite directions and forming an ultrasonic barrier, - Figure 19 shows an enlarged and sectional view of a detail of Figure 18, - Figure 20 is a view similar to that of Figure 18, with the additional presence of a physical barrier, and Figure 21 is an enlarged portion of zone XXI of Figure 20 - Figures 22 and 23 are views similar to those of Figures 18 and 19 for another embodiment in which two annular modules are mounted on the external face of a filter element,at a distance from each other, with the MROTE-4-PCTultrasonic emitting elements forming an ultrasonic barrier and emitting in the same direction, -Figures 24 and 25 are views similar to those of Figures 18 and 19 for another embodiment in which firstly two annular modules are mounted side by side on the external face of a filter element, at the end of the filter element adjacent to a pumping or discharge pipe, with the emitting elements forming an ultrasonic barrier and emitting in two opposite directions, and secondly another annular module is mounted on the external face of this filter element, at the other end of the filter element, forming another ultrasonic barrier emitting in the direction of the external face of this filter element,-Figures 26 and 27 are views similar to those of Figures 18 and 19 for a variant in which the filter element does not have a circular but a hexagonal cross-section, each module comprising six boxes to form six ultrasonic emitting elements, each covering one of the faces, with one box (ultrasonic emitting element) per face of the filter element, -Figure 28 is a view similar to that of Figure 18 for a variant for which a connector forming a fixing guide is used between the pipe and the frame carrying the filter element, in order to facilitate the assembly and disassembly of the system according to the invention, -Figure 29 shows in perspective the state of the system of Figure 28 after its separation from the pipe,- Figures 30 and 31 are views similar to that of Figure 18 for a variant for which another fixing system is used allowing the mounting of one or more modules on a cylindrical portion formed of a filtering element, Figure 30 showing the situation after mounting and Figure 31 showing the situation after dismantling of two modules placed side by side, - Figure 32 represents in perspective another embodiment of the system according to the present invention in which the ultrasonic barrier is formed of an ultrasonic emitting element arranged opposite an opening formed at the free end of the cylindrical portion which comprises a filtering element, thus covering the end face of the end section or terminal section of the cylindrical portion, - Figure 33 illustrates in exploded view the system of Figure 32, showing that the ultrasonic transducers emit in the direction of the cylindrical portion,- Figure 34 represents in perspective another embodiment of the system according to the present invention in which the ultrasonic barrier is formed of an ultrasonic emitting element arranged opposite an angular sector of the cylindrical portion which comprises a filtering element, thus covering a section of the cylindrical portion and the filtering element, - Figure 35 illustrates in exploded view the system of Figure 34, showing that the ultrasonic transducers emit in the direction of the cylindrical portion, - Figure 36 represents in perspective another embodiment of the system according to the present invention in which the ultrasonic barrier is formed of an ultrasonic emitting element arranged opposite an opening formed at the free end of the cylindrical portion, only this free end comprising a filtering element, the cylindrical portion corresponding to the terminal portion of the pipe,and said ultrasonic emitting element thus covering the end face (axial face) of the terminal section of the cylindrical portion, - Figure 37 illustrates an exploded view of the system of Figure 36, showing that the ultrasonic transducers emit in the direction of the cylindrical portion, - Figure 38 represents in perspective another embodiment of the system according to the present invention in which the ultrasonic barrier is formed of an ultrasonic emitting element arranged around an opening formed at the free end of the cylindrical portion, only this free end comprising a filtering element, the cylindrical portion corresponding to the terminal portion of the pipe, and said ultrasonic emitting element thus covering the lateral face (radial face) of the terminal section of the cylindrical portion, and - Figure 39 is an enlarged and broken away view of Figure 38,showing that the ultrasonic transducers emit towards the cylindrical portion. Example(s) of embodiment of the invention,

[0041] Dans le cadre du développement de la présente invention, des tests experimental studies were carried out. They are presented below.

[0042] Afin d’évaluer l’effet des ultrasons sur la moule quagga (Dreissena burgensis), several tests were carried out. In aquariums (60l each) two populations of 120 strictly identical individuals (size) were placed. The physicochemical parameters (pH, conductivity, temperature), mixing and luminosity were strictly controlled in order to have a standardization between the two aquariums. In a control aquarium, no experiment was carried out, while in the second, the only difference was that the filtration system (in a closed system) passed through an ultrasonic tank generating cavitation in the water volume of the latter.

[0043] Résultats : La population de D. burgensis du bac témoin croissait designificantly and the larvae had normal growth. In the other only the starting population was present and many organic debris MROTE-4-PCT were beginning to cloud the water (also an increase in conductivity). Under the microscope, the presence of dead larvae could be seen, which confirmed the effectiveness of the system.

[0044] Une autre partie du test a été de soumettre des individus adultes (attached to a rock) in the ultrasound system, turned off and then on. When there was no ultrasound, the individuals behaved normally (filtered the water to feed, moved). When ultrasound was applied, the individuals closed in their shells, then detached and died (t+5min for lethality). This test proves the inhospitable (then lethal) environment that the application of ultrasound presents in the aquatic environment.

[0045] Il a aussi été constaté que seul l’effet de cavitation engendré par lesultrasound can generate this inhospitable environment. In water at atmospheric pressure, it is with an ultrasound system power equal to or greater than the threshold of 0.5 W / cm2 that such cavitation is obtained. This is the power in Watts per unit of surface area (in cm 2 ) of the active face of the ultrasonic generating transducers. Indeed, activating the ultrasonic system at a power lower than the threshold of 0.5 W / cm2 causes the vibration of the ultrasonic tank without generating cavitation, which does not disturb the adult individuals clinging to their rock or resting on the bottom of the tank. This observation allowed us to define the need to generate cavitation in order to obtain this inhospitable environment and not only to vibrate an element on which individuals would be clinging.

[0046] A la suite des résultats probants de ces tests, le principe de l’applicationultrasonic waves in the aquatic environment near the area of ​​the room to be protected from colonization has been implemented in practice as follows with ultrasonic emitting elements and not by vibrating the area of ​​the room to be protected.

[0047] Les ultrasons permettent donc de créer un environnement inhospitalier à mollusc colonization. In the case of a water pumping system, it can be colonized in two different ways. The first is by individuals that move up the outside of the water pipe until they reach the filtering part of the strainer, then enter it and continue colonization up the inside of the water pipe to the pumps. The second way is generated by young individuals that establish themselves near their older congeners. MROTE-4-PCT

[0048] La lutte contre la colonisation par les individus remontant l’extérieur deThe pipe can be blocked by elements emitting ultrasound from the strainer towards the pipe outside of it. These ultrasound emissions will have the effect of generating cavitation directly opposite the mollusc colonization front and will block their progress.

[0049] Concernant les plus jeunes individus cherchant un substrat pour s’ycling, we know that the speed of the water flow, when it is pumped, is too fast for them to cling to the coarse filter element of the strainer or the inner face of the pipe. However, if the pumping installation is stopped, the youngest individuals could manage to cling to the surface of the filter part of the strainer, develop there and migrate inside it towards the pipe. To overcome this situation, ultrasonic emitting elements can be placed so as to generate cavitation on the filter part of the strainer and kill the young individuals near it when the pumping installation is stopped.

[0050] On se reporte maintenant aux figures 4, 5 et 7 représentant un exemple assembly of a suction strainer equipped with an anti-colonization system according to the invention.

[0051] La crépine d’aspiration 103 d’eau comporte un châssis 101 relié à unesuction line 200, and a coarse filter element 102. In the illustrated assembly, the suction strainer 103 is supplemented by ultrasonic barriers 110 and 120 as well as a geometric barrier or physical barrier 140.

[0052] La crépine est montée en bout de la conduite d’aspiration 200, au niveau of opening 201a of this pipe 200.

[0053] Le châssis 101 constitue la pièce de liaison entre les éléments de la suction strainer 103 (frame 101 and filter element 102) and the water suction pipe 200.

[0054] L’élément filtrant grossier 102 est constitué d’une grille métallique perforated. It is mounted on the frame 101 and prevents coarse elements, such as plants or living organisms of a certain size, found in the water from being sucked up by the suction strainer 103.

[0055] Un ou plusieurs éléments émetteurs d’ultrasons 170 constituent la ultrasonic barrier 110, 120 or 130. For example, in Figure 5, the first ultrasonic barrier 110 has four ultrasonic emitting elements 170 MROTE-4-PCT each in the shape of a quarter circle and the four of them forming a ring surrounding the annular section of the cylindrical portion 150 near the filter element 102.

[0056] Ces éléments émetteurs d’ultrasons 170 forment des pavés immergés mounted one by one above the cylindrical portion 150 equipped with the water inlet or outlet opening 151.

[0057] Un élément émetteur d’ultrasons 170 est délimité par un caisson étanche 171 comprising an outlet passage for an electrical connection. In Figure 6, the connecting cable 163 is seen passing through said passage in the wall of the box 171 (with a sealing element 164 not visible), and which is connected to one of the ultrasonic transducers 172, then a cable forming a connecting portion 172a connects two neighboring ultrasonic transducers 172 together in order to power each ultrasonic transducer 172.

[0058] Le caisson 171 est en matériau métallique. L’intérieur du caisson 171 comprises ultrasonic transducers 172 fixed on an inner face of the sheet metal of the waterproof box as can be seen in the example of figure 6. These ultrasonic transducers 172 are connected to each other by an electrical connection (connection cable 163 and connection portion 172a) which transmits to them the electrical signal allowing them to be activated.

[0059] Les figures 10 à 12 présentent différentes possibilités de commande etarrangement for the operation of the ultrasonic transducers 172 and therefore of the ultrasonic emitting elements 170 forming the ultrasonic barrier(s) 110, 120 and 130 presented later. Possible arrangements of the ultrasound part of the colonization control system 100 according to the invention are therefore set out. It should be understood that the elements shown on the right in Figures 10 to 12 are those which will be immersed in water and the elements shown on the left in Figures 10 to 12 will not be immersed in water but will remain in the open air. In Figure 10, this is a situation without pressurizing the sealed box 171 of each ultrasonic emitting element 170 with air. This is possible in particular for an immersion depth of the ultrasonic emitting elements 170 less than or equal to 3 meters deep. A non-immersed electronic control device 160 is connected by a connecting cable 161 to a high frequency generator 162.The latter is connected by a high-frequency connection cable 163 to the ultrasonic transducers 172 placed in the waterproof box 171. To prevent the entry of water into the waterproof boxes 171 filled with air, a sealing element 164 housed in a passage in the wall of the MROTE-4-PCT. box 171. It can also be seen that the ultrasonic emitting element 170 is arranged opposite the suction strainer 103.

[0060] Sur la figure 11, on considère le cas d’une profondeur d’immersion desultrasonic emitting elements 170 greater than 3 meters deep. In this case, for the proper functioning of the ultrasonic part at a depth greater than 3m in addition to the elements previously described in relation to figure 10, a pressurization of the air-filled sealed boxes 171 is used. This makes it possible to generate cavitation without increasing the power of the ultrasonic transducers 172 of the ultrasonic emitting elements 170. For this purpose, a pneumatic supply 180, or pressurized air supply, is used. A pneumatic line 181 or pressurized air line connects the pneumatic supply 180 to each sealed box 171. As an alternative to the arrangement of Figure 11 in which the pneumatic line 181 is independent and separate from the high-frequency connection cable 163, the arrangement of Figure 12 provides that the pneumatic line 181 also acts as a protective sheath for the high-frequency connection cable 163.For this purpose, after leaving the high-frequency generator 162, the high-frequency connecting cable 163 enters an introduction piece 181a forming a part of the pneumatic conduit 181, with the interposition of a sealing element 181b between the high-frequency connecting cable 163 and the introduction piece 181a. This arrangement is simpler, with fewer components and more reliable in terms of the sealing of the boxes 171 which have only one entry point for the pneumatic conduit 181 which contains the high-frequency connecting cable 163.

[0061] Dans les cas requérant une mise sous pression des caissons 171,the pneumatic supply 180 sends into each caisson an air pressure of a value greater than or equal to the difference between the water pressure value at the immersion location of said caisson 171 and 0.3 bar. Thus, from a depth of 3 m, the pneumatic supply 180 provides pressurized air with a pressure value P greater than or equal to the difference between (1 bar + p / 10 bar) and 0.3 bar with p the immersion depth of the caissons 171. In other words, P ≥ [(1 + p / 10) – 0.3] with P in bar and p in meters. For example, at a depth of 6 m, the pressure P provided by the pneumatic supply 180 is equal to or greater than 1.3 bar, for example 1.4 bar or 1.5 bar, 1.8 or 1.9 bar.

[0062] Lorsque les éléments émetteurs d’ultrasons 170 sont immergés à uneimmersion depth greater than 3 meters, it is possible, as an alternative to overpressurizing the air-filled watertight boxes 171 to counterbalance the water pressure, to increase the power of the ultrasonic transducers 172 to a value ensuring the creation of cavitation at the target depth.

[0063] Lorsque les transducteurs ultrasoniques 172 sont activés, les ondesultrasonic waves are emitted from the sheet metal of the box 171, by its emission face 173, towards the outside of the box 171, and penetrate into the water in a certain direction by the external face of the sheet metal on which the ultrasonic transducers 172 are fixed. This direction of emission of the ultrasonic waves is defined according to the direction of mounting of the ultrasonic emitting element 170 on the ultrasonic barrier, namely in particular the orientation of the sheet metal of the waterproof box physically carrying the active face of the ultrasonic transducers 172. In Figure 6, this emission face 173 is the external face of the lower wall of the box 171, on which the active face of the ultrasonic transducers 172 is secured, and the ultrasonic waves are emitted towards the bottom of the box 171.

[0064] Il est important de relever que selon la présente invention, lesultrasonic transducers 172 of the ultrasonic barriers emit ultrasonic waves which propagate outside the box 171 and penetrate into the water, but which do not affect the cylindrical portion 150 which carries the box 171. Indeed, the ultrasonic transducers 172 are not in contact with the cylindrical portion 150. Therefore, no vibration phenomenon is generated in the structure of the installation to be protected from colonization and which carries the control system according to the present invention. The absence of vibration of the cylindrical portion 150, and therefore of the structure of the installation to be protected, not only avoids their damage, but also avoids an energy requirement necessary to reach the very significant cavitation power threshold which is thus very limited.

[0065] Dans cet exemple de réalisation des figures 4, 5 et 7, une premièreultrasonic barrier 110 is fixed on the frame 101 of the suction strainer 103, as close as possible to the coarse filter element 102, between the coarse filter element 102 and the end of the frame 101 facing the suction pipe 200. This first ultrasonic barrier 110 consists of ultrasonic emitting elements 170 mounted around the entire circumference of the suction strainer 103, so as to emit the ultrasound in the direction of and parallel to the suction pipe 200. This first ultrasonic barrier 110 forms a ring around the frame 101. In one embodiment, the ultrasound is not emitted parallel to the direction of the suction pipe 200, but with a slight incidence directed inMROTE-4-PCT direction of the suction line 200, in order to form a sheet of ultrasonic waves against the suction line 200. The first ultrasonic barrier 110 is activated by the operation of the ultrasonic emitting elements 170. The activation of the first ultrasonic barrier 110 makes it possible to repel the colonization of the suction strainer 103 by molluscs located in the water when the water is sucked through the suction line 200 (active strainer) and also when the water is not sucked through the suction line 200 (passive strainer). This activation can be carried out continuously or intermittently.

[0066] En plus de cette première barrière ultrasonique 110 montée sur lasuction strainer 103 towards the suction pipe 200, the suction strainer 103 comprises a second ultrasonic barrier composed of ultrasonic emitting elements 170 emitting towards the filter element 102 of the suction strainer 103. These ultrasonic emitting elements 170 have the role of repelling the colonization of the suction strainer by veliger larvae (drifting planktonic stage) found in the water when the latter is not sucked by the suction pipe 200 (passive strainer). For this purpose, this second ultrasonic barrier 120 is composed of ultrasonic emitting elements 170 mounted around the entire periphery of the suction strainer 103, on each side of the filter element 102 so as to emit the ultrasound in the direction of and parallel to the filter element 102. This second ultrasonic barrier 120 forms a double ring around the frame 101, on either side of the filter element 102.Here, each ring comprises four ultrasonic emitting elements 170. In one embodiment, the ultrasound is not emitted parallel to the direction of the frame 101 and the strainer, but with a slight incidence directed towards the filter element 102, in order to form two sheets of ultrasonic waves covering the filter element 102. This inclination of the direction of emission of the ultrasonic waves with respect to the longitudinal direction and towards the central axis of the strainer can also be applied to the first ultrasonic barrier 110. The second ultrasonic barrier 120 is activated by the operation of the ultrasonic emitters. This activation can be carried out continuously or intermittently.

[0067] En plus de cette première barrière ultrasonique 110 montée sur lasuction strainer 103 towards the suction line 200, the suction strainer 103 of the embodiment illustrated in Figures 4 and 5 comprises a third ultrasonic barrier 130 mounted on the end of the suction strainer 103, namely here on the end plate of the frame 101 of the suction strainer 103. This third ultrasonic barrier 130 is in this example composed of two additional ultrasonic emitting elements 170. These each comprise a series of transducers generating ultrasonic waves fixed on one of the walls of a metal box. These two additional ultrasonic emitting elements 170 forming the third ultrasonic barrier 130 are placed parallel to each other and form two lines of ultrasonic emitting elements placed back to back, in order to emit in two opposite directions on either side of a line dividing the end of the suction strainer 103 in two.Thus, by emitting the ultrasonic waves from this line in two opposite directions, the activation of this pair of ultrasonic emitting elements 170 generates a cavitation in a volume of water located close to and above the area corresponding to the majority of the surface of the end of the suction strainer 103. The function of this third ultrasonic barrier 130 is to protect the upper part (or more generally the terminal part) of the suction strainer 103 against the implantation and development of aquatic mollusk larvae thereon. Other geometric arrangements are possible for this third ultrasonic barrier 130, which may comprise more than two ultrasonic emitting elements 170.

[0068] A titre d’exemple, que ce soit pour la première barrière ultrasonique 110 or for the second ultrasonic barrier 120 or for the third ultrasonic barrier 130, ultrasonic emitting elements 170 may be used whose frequency is between 20 and 70 KHz, or between 20 and 40 KHz.

[0069] Ces émetteurs d’ondes ultrasonores 170 peuvent tous fonctionner en emitting waves simultaneously. These ultrasonic wave emitters 170 can operate continuously (continuous activation) or intermittently with time intervals of operation and emission of ultrasonic waves alternating with time intervals without operation and without emission of ultrasonic waves. When they operate intermittently, they can, for example, be operated for 30 seconds every 5 minutes. When they operate intermittently, all the ultrasonic wave emitters 170 can be operated simultaneously, or the ultrasonic wave emitters 170 can be operated with a time shift. It is also possible to operate some of the ultrasonic wave emitters 170 continuously and to operate the rest of the ultrasonic wave emitters 170 intermittently.MROTE-4-PCT

[0070] En supplément de l’une, l’autre ou plusieurs des barrières ultrasoniques,a physical barrier or geometric barrier 140 is located on the suction strainer 103 to block the colonization of the installation by aquatic molluscs advancing along the suction pipe 200. This physical barrier or geometric barrier 140 consists of a crown fixed or formed on the periphery of the frame 101 of the suction strainer 103. This physical barrier or geometric barrier 140 in the form of a collar or full flange constitutes a rampart arranged between the first ultrasonic barrier 110 and the suction pipe 200. For example, this physical barrier or geometric barrier 140 is arranged between 20 and 50 cm from the first ultrasonic barrier 110 in the direction of the suction pipe 200 (distance D in figure 7).This physical barrier or geometric barrier 140 acts as an obstacle so that the mussels cannot crawl across and therefore progress towards the filtering part of the suction strainer 103. This physical barrier or geometric barrier 140 has, for example, a height of between 5 and 10 cm. In the example illustrated in FIG. 7, this physical barrier or geometric barrier 140 comprises a first portion 140a formed by a solid annular wall extending substantially radially outwards from the wall of the frame 101, this first portion 140a being extended by a second portion 140b formed by a solid annular wall turned towards the suction pipe 200 and forming an acute angle with the first portion 140a.This second portion 140b constitutes a rim facing in the opposite direction to the opening of the strainer (namely here the filter 102), which adds an obstacle that is difficult to overcome by means of the sliding / creeping movement of the mollusk's foot. Preferably the free end of this second portion 140b is pointed. Thus, with this second portion 140b, the physical barrier or geometric barrier 140 has a hook shape in section with the pointed end.

[0071] Cet exemple de réalisation permet donc de former un assemblageemitting ultrasounds opposing the movement of the mussels on the pumping installation as well as creating an inhospitable environment for the development of aquatic molluscs. The geometric barrier 140 is a design element which prevents the mussels from moving up the suction pipe 200 to the filtering part of the suction strainer 103. In Figures 8 and 9, the mussels can move (arrows A) from the outer face of the suction pipe 200 throughout the zone Z1 and are then stopped by the geometric barrier 140. Between the geometric barrier 140 and the first ultrasonic barrier 110, specimens which would have managed to MROTE-4-PCT attach themselves from the surrounding liquid environment may persist: this is the zone Z2 of possible end of colonization or also called colonization blocking zone.The ultrasonic barrier is an element emitting ultrasonic waves in the direction opposite to the direction of progression of mussel colonization. In this way, any colonization is prevented beyond the first ultrasonic barrier 110 in the direction of the filter element 102, corresponding to the uncolonized zone Z3.

[0072] D’autres modes de réalisation (non illustrés) sont possibles dans le cadreof the present invention, and in particular:- an assembly with the first ultrasonic barrier 110 but without the second ultrasonic barrier 120, without the third ultrasonic barrier 130 and without the physical barrier or geometric barrier 140,- an assembly with the second ultrasonic barrier 120 but without the first ultrasonic barrier 110, without the third ultrasonic barrier 130 and without the physical barrier or geometric barrier 140,- an assembly with the first ultrasonic barrier 110 and the second ultrasonic barrier 120, but without the third ultrasonic barrier 130 and without the physical barrier or geometric barrier 140,- an assembly with the first ultrasonic barrier 110 and with the third ultrasonic barrier 130 but without the second ultrasonic barrier 120, and without the physical barrier or geometric barrier 140,- an assembly with the second ultrasonic barrier 120 and with the third ultrasonic barrier 130 but without the first ultrasonic barrier 110, and without the physical barrier or geometric barrier 140,- an assembly with the first ultrasonic barrier 110 and with the physical barrier or geometric barrier 140, but without the second ultrasonic barrier 120 and without the third ultrasonic barrier 130,- an assembly with the second ultrasonic barrier 120 and with the physical barrier or geometric barrier 140, but without the first ultrasonic barrier 110, and without the third ultrasonic barrier 130,- an assembly with the first ultrasonic barrier 110, the second ultrasonic barrier 120 and with the physical barrier or geometric barrier 140, but without the third ultrasonic barrier 130,- an assembly with the first ultrasonic barrier 110,with the third ultrasonic barrier 130 and with the physical barrier or geometric barrier 140 but without the second ultrasonic barrier 120, - an assembly with the second ultrasonic barrier 120, with the third ultrasonic barrier 130 and with the physical barrier or geometric barrier MROTE-4-PCT, 140, but without the first ultrasonic barrier 110, - an assembly with the third ultrasonic barrier 130 but without the first ultrasonic barrier 110, without the second ultrasonic barrier 120 and without the physical barrier or geometric barrier 140.

[0073] Un premier exemple d’élément émetteur d’ultrasons 170 est illustré surFigures 13A and 13B. This ultrasonic emitting element 170 is in the shape of an arc of a circle with a central angle of 90°. As seen in Figure 13A, the sealed box 171 contains a series of ultrasonic transducers 172 aligned along the metal box 171, with their active face through which the ultrasonic waves are emitted placed and fixed on the lower wall of the box, the external face of which forms the emission face 173 of the ultrasonic emitting element 170. Cables 172a connect the ultrasonic transducers 172 in series for the electrical connection between the ultrasonic transducers 172. The box 171 comprises in its end portions a connector 171a for the introduction of pressurized air and / or high-frequency connection wiring 163. The box 171 further comprises at each end a fixing lug 175d with holes.

[0074] Un deuxième exemple d’élément émetteur d’ultrasons 170 est illustré surFigures 14A and 14B. This ultrasonic emitting element 170 differs from that of figures 13A and 13B in that it comprises two series of ultrasonic transducers 172 aligned along and inside the metal box 171. The active face of the first series of ultrasonic transducers 172 is placed and fixed on the lower wall of the box 171, the external face of which forms a first emission face 173 of the ultrasonic emitting element 170. The active face of the second series of ultrasonic transducers 172 is placed and fixed on the upper wall of the box 171, the external face of which forms a second emission face 173 of the ultrasonic emitting element 170. Thus, this ultrasonic emitting element 170 emits ultrasonic waves from its two opposite emission faces 173, and in two opposite directions (upwards and downwards). the bottom in Figures 14A and 14B).

[0075] Sur la figure 15, est visible un module 190 assemblé apte à être montéon a cylindrical portion 150 such as the filter element 102 or the frame 101 of a suction strainer 103. This module 190 is annular and is visible exploded in figure 16, and after mounting on the filter element 102 (forming the cylindrical portion 150) in figure 17. This mounting of figure 17 can correspond to an implementation of one or the other of the two rings of the second ultrasonic barrier 120 visible in figures 4, 5 and 9. MROTE-4-PCT

[0076] D’une manière générale, un tel module 190 comporte toutes les piècesrequired for the operation of the system according to the invention. It comprises one or more ultrasound emitting element(s) 170, including the box 171 with connector(s) 171a and pipes 174, as well as a box fixing assembly 175, the high-frequency connecting cable 163 and, if required, the pneumatic pipe 181. Connection pipes 174 are used between the ultrasound emitting elements 170, for the electrical connection and, if required, the pressurization of the boxes 171. These connection pipes 174 make it possible to form a connection chain between all the ultrasound emitting elements 170 of the same ultrasonic barrier which are close to each other.The assembly 175 for fixing the boxes comprises the pierced fixing lugs 175d of the boxes 171, pierced fixing supports 175c mounted on the suction strainer 103 or generally on the cylindrical portion 150, pierced damping spacers 175b and fixing screws 175a. The fixing screws 175a make it possible to connect together a fixing lug 175d, a fixing support 175 and a damping spacer 175b as seen in FIG. 17. The damping spacers 175b are made of a damping material, for example rubber. They make it possible to prevent the transmission of vibrations to the suction strainer 103 or to the cylindrical portion 150, and to correct alignment errors when mounting the module 190.

[0077] Sur les figures 18 et 19, ce sont deux modules 190 annulaires analogues àthat of figures 15 to 17 which are used to form the ultrasonic barrier 110. These two modules 190 are mounted side by side on the external face of a filter element 102, approximately halfway up this filter element 102. The ultrasonic emitting elements 170 of each module 190 form a ring, the two rings of ultrasonic emitting elements 170 (of ultrasonic wave generating transducers 172) emit in two opposite directions and form an ultrasonic barrier to protect the filter element 102. Indeed, as can be seen in figure 19, the emission faces 173 of each of the two rings of ultrasonic emitting elements 170 being oriented opposite to the position of the other ring, the ultrasonic waves leave the ultrasonic barrier towards the top and bottom in Figure 19, thus covering both halves of the filter element102.In other words, one of the two rings of ultrasonic emitting elements 170 (of ultrasonic wave generating transducers 172) emits in the direction of the pipe 200 and the other emits in the opposite direction to the pipe 200. The presence of mussels is thus prevented near the opening 151 formed by the spaces of the filter element 102. MROTE-4-PCT.

[0078] La figure 20 est une variante du mode de réalisation des figures 18 et 19,with the additional presence of a geometric or physical barrier 140. This geometric barrier 140, visible enlarged in Figure 21, forms a skirt acting as a physical barrier to the progression of colonization. This geometric barrier 140 is placed at the connection point between the base 101a and the filter element 102 of the suction strainer 103. Except in Figures 4, 5 and 7 to 9, this geometric barrier 140 is not illustrated in the figures of the other variants or embodiments but it can be used in all cases. The system for combating colonization by aquatic molluscs of an installation submerged in water comprising a cylindrical portion can therefore comprise a geometric barrier 140, in the form of a skirt surrounding the cylindrical portion.

[0079] Les figures 22 et 23 illustrent une autre variante du mode de réalisationof Figures 18 and 19. In this case, the two modules 190 are mounted at a distance from each other on the external face of a filter element 102. One of the modules 190 is mounted at the end of the filter element 102 opposite the pipe 200, and the other module 190 is mounted approximately halfway up this filter element 102. The ultrasonic emitting elements 170 of each module 190 form a ring, the two rings of ultrasonic emitting elements 170 (of ultrasonic wave generating transducers 172) emit in the same direction, towards the pipe 200 and form an ultrasonic barrier 110 to protect the filter element 102. Each of the two rings of ultrasonic emitting elements 170 (of ultrasonic wave generating transducers ultrasonic waves 172) emitting towards the pipe 200, each covers the space surrounding one of the halves of the filter element 102 according to its height.

[0080] Sur les figures 24 et 25, on utilise une première barrière ultrasonique 110and a second ultrasonic barrier 120. For this purpose, three annular modules 190 similar to those of Figures 15 to 17 are used, one being used to form the first ultrasonic barrier 110 and two being used to form the second ultrasonic barrier 120. The ultrasonic emitting elements 170 of each module 190 form a ring. The first ultrasonic barrier 110 surrounds the end of the filter element 102 closest to the pipe 200, with the ring of ultrasonic emitting elements 170 (of ultrasonic wave generating transducers 172) emitting towards the pipe 200. This first ultrasonic barrier prevents the MROTE-4-PCT colonization of the base 101a of the frame carrying the filter element 102. The second ultrasonic barrier 120 comprises two modules 190 which are mounted at a distance from each other on the external face of the filter element 102. The first module 190 is mounted at the end of the filter element 102 opposite from the pipe 200 (at the top in Figures 24 and 25), and the second module 190 is mounted next to the module 190 forming the first ultrasonic barrier 110, between it and the first module 190. For the second ultrasonic barrier 120, the two rings of ultrasonic emitting elements 170 (of ultrasonic wave generating transducers 172) emit in opposite directions, one towards the other and towards the middle of the height of the element filtering element 102. This second ultrasonic barrier 120 prevents colonization on the filtering element 102.

[0081] Les figures 26 et 27 illustrent une autre variante du mode de réalisationof Figures 18 and 19 for a suction strainer 103 whose filter element 102 forming the cylindrical portion 150 to be protected is not of circular section. This section is hexagonal, so that the cylindrical portion 150 has six flat faces. Each module 190 comprises six boxes 171 to form six ultrasonic emitting elements 170, each covering one of the faces, with one box 171 (ultrasonic emitting element 170) per face of the filter element 102.

[0082] Les figures 28 et 29 illustrent une autre variante du mode de réalisationof figures 18 and 19 for a suction strainer 103 for which a connector 201 is used forming a fixing guide between the end of the pipe 200 and the frame 101 carrying the filtering element 102, in order to facilitate the assembly and disassembly of the system 100. The filtering element 102 and the base 101 thus form a removable whole with the two modules 190 forming the ultrasonic barrier 110. It is thus easy to carry out maintenance or repair of the ultrasonic emitting elements 170 without disassembling them from the filtering element 102. This variant also includes a lifting point 103a of the strainer 103, in the form of a pierced gripping tab located on the end wall of the cylindrical portion 150 (of the filtering element 102).

[0083] Les figures 30 et 31 illustrent une autre variante du mode de réalisationof figures 18 and 19 for an ultrasonic barrier 110 belonging to a module 190 equipped with a fixing system 175' different from the fixing system 175 previously exposed. This other fixing system 175' allows removable mounting of one or more modules 190 on a cylindrical portion 150 formed of a filter element MROTE-4-PCT 102. As can be seen better in the exploded view in Figure 31, this fixing system 175' is formed of a fixing frame in the form of an openwork cap, which can be directly fitted onto the filter element 102 of the strainer 103. It is on this fixing frame that the module(s) 190 forming the ultrasonic barrier(s) is / are mounted. This variant also includes a lifting point 190a of the fixing frame, in the form of a pierced gripping tab located for example on the end of the fixing system 175'.

[0084] Selon un autre mode de réalisation du système selon la présenteinvention, as visible in Figures 32 and 33, the ultrasonic barrier 110 is formed of a single ultrasonic emitting element 170 arranged opposite an opening 151 formed at the free end of the cylindrical portion 150 which comprises a filtering element 102, thus covering the end face of the end section or terminal section 150c of the cylindrical portion 150. In the configuration shown, this ultrasonic emitting element 170 closes the opening 151 or at least restricts its amplitude, by being placed against the free end of the cylindrical portion 150 or close to the free end of the cylindrical portion 150 (less than 3 cm, preferably between 0.5 and 1 cm, for example approximately 1 cm). This ultrasonic emitting element 170 comprises a plurality of ultrasonic wave generating transducers 172.The active face of these ultrasonic wave generating transducers 172, through which the ultrasonic waves are emitted, is placed and fixed on the lower wall of the box 171, the external face of which forms the emission face 173 of the ultrasonic emitting element 170. This emission face 173 is orthogonal to the main direction or axis of the cylindrical portion 150 and of the filtering element 102. Thus, said ultrasonic emitting element 170 emits waves in the direction of the opening 151 of the terminal section 150c of the cylindrical portion 150, of the entire cylindrical portion 150 and of the pipe 200. Advantageously, said ultrasonic emitting element 170 is configured so that the propagation distance of the waves is at least 50 cm. This is valid for all the embodiments presented and envisaged in the present text.The transducers 172 can be placed in a circular manner on the lower wall of the box 171, the external face of which forms the emission face 173. Alternatively, two or more, therefore several, ultrasound emitting elements 170 can be provided, placed side by side at the free end of the cylindrical portion 150. This terminal arrangement of the ultrasound emitting element 170 forming the ultrasound barrier 110 is also applicable in the case of an MROTE-4-PCT portion. cylindrical / of a filter element 102 with a closing wall or plug closing the opening 151. In this case, the spaces in the wall of the filter element 102 form an opening for the passage of liquid at the outlet or inlet.

[0085] Au lieu de la disposition terminale précitée, on peut prévoir unefrontal or axial arrangement as illustrated in Figures 34 and 35. This is another embodiment of the system according to the present invention, in which the ultrasonic barrier 110 is formed of a single ultrasound emitting element 170 arranged axially along the filter element 102, opposite a portion of the periphery of the filter element 102. This ultrasonic wave emitting element 170 is thus able to cover an angular sector of the cylindrical portion 150 which comprises a filter element 102, thus covering an axial section of the cylindrical portion 150 and of the filter element 102. Thus, the ultrasonic wave emitting element 170 is placed on the side of the filter element 102 of the suction strainer 103 and emits the ultrasound in a direction perpendicular to the axis of the cylindrical portion 150 and of the pumping line 200.The strainer has a cap or end wall which closes it on top, at the end opposite the suction pipe 200. The transducers can be placed in an alignment of several columns on the wall of the box 171 corresponding to the emission face 173 of the ultrasonic waves, so as to cover the entire length of the filter element 102. As shown, according to one possibility for the fixing assembly 175 allowing the mounting of the box 171 on the suction strainer 103, annular fixing supports 175c enclose the cylindrical portion 150 near each end of the filter element 102.

[0086] Les figures 36 et 37 illustre un mode de réalisation proche de celui desFigures 32 and 33. We find a similar system 100 with a single ultrasonic barrier 110 formed by an ultrasonic emitting element 170 arranged opposite an opening 151 formed at the free end of the cylindrical portion 150. In this case, only this free end of the cylindrical portion 150 comprises a filtering element 102 (in the figures, it is a circular plane filtering element). There is no cylindrical filtering element constituting a length of the cylindrical portion 150, as in the case of Figures 32 and 33. In the embodiment of Figures 36 and 37, the cylindrical portion 150 corresponds to the terminal portion of the pipe 200, and said ultrasonic emitting element thus covers the end face (axial face) of the terminal section of the cylindrical portion 150. MROTE-4-PCT In the embodiment of Figures 36 and 37, due to the presence of the filter element 102 covering the opening 151 at the free end of the cylindrical portion 150, the box 171 of the ultrasound emitting element 170 is not in contact with the filter element 102. In order to allow the water to pass through the opening 151 without pressure loss, the box 171 of the ultrasound emitting element 170 is spaced from this opening, for example by 1 to 25 cm, and preferably by at least 10 cm. This gap between the ultrasound emitting element 170 and the opening 151 does not impair the efficiency of the system because it is only the opening 151 located at the end of the cylindrical portion 150 which must be protected from colonization and the wave propagation distance, for example at least 50 cm, is sufficient for this purpose.As seen in Figure 37 and similarly to the embodiment of Figures 32 and 33, the ultrasonic transducers 172 emit from the emission face 173 towards the cylindrical portion 150.

[0087] Sur les figures 38 et 39, on retrouve un agencement de crépinesuction (or discharge) 103 which is similar to that of figures 36 and 37, namely with a filter element 102 covering only the free end of the cylindrical portion 150. In this embodiment, the system 100 comprises an ultrasonic barrier 110 which comprises a single annular module 190 mounted around the terminal section 150c of the cylindrical portion. The ultrasonic barrier 110 is formed of several (here four) ultrasonic emitting elements 170 in the shape of a quarter circle, forming a crown arranged around the opening 151 and therefore around the filter element 102. For example, the cylindrical portion 150 corresponds to the terminal portion of the conduit 200. Said ultrasonic emitting elements 170 form a ring thus covering the lateral face (radial face) of the terminal section 150c of the cylindrical portion 150.As best seen in the enlarged view of Figure 39, the ultrasonic transducers 172 emit from the emission face 173 of the ultrasonic emitting element 170 towards the cylindrical portion 150 in order to prevent colonization by mollusks of the cylindrical portion 150 or at least of the terminal section 150c of the cylindrical portion 150. In a variant of this embodiment, not illustrated, two annular modules 190 placed side by side around the terminal section 150c of the cylindrical portion 150 can be used. A first annular module 190, the one closest to the filter element 102, emits the ultrasonic waves outwards, either in a radial direction or in an axial direction in the direction opposite to the pipe 200. A second annular module 190, the one furthest from the filter element 102, MROTE-4-PCT. emits the ultrasonic waves in the axial direction towards the pipe 200, as in Figures 38 and 39.

[0088] D’une manière générale, la présente invention porte également sur unsystem 100 for combating the colonization of an installation submerged in water by aquatic molluscs, said system comprising ultrasonic wave emitting elements 170 generating cavitation at the location of a structural zone of the submerged installation to be protected against colonization by aquatic molluscs. The generated cavitation creates an environment inhospitable to aquatic molluscs, thus preventing them from colonizing the submerged installation.

[0089] Le système selon la présente invention comprend en outre l’une ouseveral of the following arrangements:- the system comprises at least one ultrasonic wave emitting element 170. This ultrasonic wave emitting element 170 being essentially composed of a metal box 171, an electrical connection as well as ultrasonic wave generating transducers 172 fixed on one of the walls of the metal box 171.- the ultrasonic wave generating transducers 172 operate at a frequency between 20 and 70 KHz, preferably between 20 and 40 KHz.- the ultrasonic wave generating transducers 172 operate continuously or intermittently.- the system comprises ultrasonic wave emitting elements 170 which are installed so as to generate cavitation on an area to be directly protected from colonization (barrier elements in figures 4, 5 and 7 to 9).- the system comprises ultrasonic wave emitting elements 170 which are installed so as to generate cavitation on an area representing a path for colonization by aquatic molluscs of the submerged installation (barrier elements in figures 4, 5 and 7 to 9).- the system 100 is mounted on a submerged water suction strainer 163.- the system 100 is mounted on a heat exchanger submerged in water.

[0090] Dans le présent texte, on peut remplacer l’expression « conduite suction » 103 by pumping pipe, or by a drain pipe allowing the discharge of liquid through the opening of said pipe.

[0091] Selon une autre solution indépendante, couverte par les différents examples, embodiments and variants described in the present text and / or illustrated in the figures, a system (100) is provided for combating colonization by aquatic molluscs of an installation submerged in water comprising MROTE-4-PCT a cylindrical portion (150) with an opening (151) allowing the entry or exit of water, comprising a first ultrasonic barrier (110) comprising at least one first ultrasonic wave emitting element (170) integral with said cylindrical portion (150), and capable of emitting ultrasonic waves into the aquatic environment, so that said ultrasonic waves allow the creation of cavitation opposite an area of ​​the surface of the cylindrical portion (150)

[0092] Selon une autre solution indépendante, couverte par les différentsexamples, embodiments and variants described in the present text and / or illustrated in the figures, an installation is provided comprising a part immersed in water comprising a cylindrical portion (150) with an opening allowing the entry or exit of water, said cylindrical portion (150) being equipped with at least one first ultrasonic barrier (110) comprising at least one first ultrasonic wave emitting element (170) capable of emitting ultrasonic waves into the aquatic environment via an emission face, so that said ultrasonic waves allow the creation of cavitation opposite an area of ​​the surface of the cylindrical portion (150).

[0093] Selon une disposition possible pour toutes les solutions présentées, ladite emitting face (173) of said ultrasonic wave emitting element (170) is not in contact with the cylindrical portion (150). This emitting face (173) may be at a distance and / or oriented in a direction other than the direction directed towards the cylindrical portion (150).

[0094] Références :- for figures 1 and 2: pages 26 and 27 of the Final Report; Bibliographic summary “Biology, ecology and potential impacts of Dreissena rostriformis bugensis, quagga mussel, invasive species in Lake Geneva”; Beisel Jean-Nicolas – August 2021 (International Commission for the Protection of the Waters of Lake Geneva) - for figure 3: https: / / coast.ifremer.fr / Projets / Projets-termines / DILEMES-dispersion-larvaire-de-la-moule; Laboratoire de Géomorphologie et EnvironnementLittoral – UMR 8586 CNRS / EPHE; Nicolas Toutpoint, and - for figure 6: Adaptation of https: / / coast.ifremer.fr / Projets / Projets- MROTE-4-PCT Reference signs used in the figures Anti-colonization system Châssis a EmbaseFilter element of the strainer (filtering area)Suction or discharge strainerFirst ultrasonic barrierSecond ultrasonic barrierThird ultrasonic barrierGeometric barrier or physical barriera First portion of the geometric barrierb Second portion of the geometric barrierCylindrical portiona Section forming a perimeter of the cylindrical portion, for example annular sectionb Axial section of the cylindrical portionc End section of the cylindrical portionOpening Free end of the cylindrical portionElectronic control deviceConnecting cableHigh frequency generatorHigh frequency connecting cableSealing elementUltrasonic emitting element (Immersed block) Caisson a Pressurized air inlet connections and / or high frequency connection wiring T ransducteurMROTE-4-PCT172a Electrical connection between transducers173 Ultrasonic wave emission face174 Connection pipe between the ultrasonic emitting elements.175 Box fixing assembly175' Box fixing assembly (Fixing frame)175a Fixing screw175b Damping spacer175c Fixing bracket175d Fixing bracket180 Pneumatic supply (pressurized air)181 Pneumatic line (Pressurized air supply line)181a Insertion piece for high-frequency cable into the line181b Sealing element between the cable and the introduction piece190 Module190a Lifting point of the module200 Suction, pumping or drain line200a Opening201 Fixing guide103a Lifting point of the suction or drain strainerA Direction of progression of the mollusksD Safety distance between the physical barrier 140 and the ultrasonic barrier 110Z1 Zone which can be colonizedZ2 Zone where colonization can end (colonization blocked)Z3 Uncolonized areaMROTE-4-PCT.

Claims

Claims1. System (100) for combating colonization by aquatic molluscs of an installation submerged in water comprising a cylindrical portion (150) with an opening (151) allowing the entry or exit of water, comprising a first ultrasonic barrier (110) comprising at least one first ultrasonic wave emitting element (170) capable of covering a first section of said cylindrical portion (150), and of emitting ultrasonic waves into the aquatic environment, so that said ultrasonic waves allow the creation of cavitation opposite an area of ​​the surface of the cylindrical portion (150).

2. System (100) according to claim 1, wherein said first ultrasonic wave emitting element (170) emits ultrasonic waves through an emission face (173) which is not in contact with the cylindrical portion (150).3.System (100) according to claim 1 or 2, wherein said first ultrasonic wave emitting element (170) is capable of emitting ultrasonic waves in the direction opposite to said opening (151).

4. System (100) according to claim 1 to 3, wherein said first ultrasonic wave emitting element (170) is capable of emitting ultrasonic waves in the direction of said opening (151).5.System (100) according to one of claims 1 to 4, further comprising a second ultrasonic barrier (120) comprising a second ultrasonic wave emitting element (170) capable of covering a second section of said cylindrical portion (150) and a third ultrasonic wave emitting element (170) capable of covering a third section of said cylindrical portion (150), said second section and said third section being located on either side of said opening (151), said second and third ultrasonic wave emitting elements being capable of emitting ultrasonic waves into the aquatic environment in the direction of said opening (151), so that said ultrasonic waves allow the creation of cavitation in an area opposite said opening (151). MROTE-4-PCT.

6. System (100) according to one of claims 1 to 5, further comprising a third ultrasonic barrier (130) comprising a set of at least two ultrasonic wave emitting elements (170), capable of being arranged on the end of the cylindrical portion (150), the ultrasonic wave emitters (170) of this set being arranged next to each other, and being capable of emitting ultrasonic waves into the aquatic environment in opposite directions to each other.

7. System (100) according to one of claims 1 to 6, wherein said first ultrasonic wave emitting element (170) is capable of covering said opening (151) formed at the free end of the cylindrical portion (150) which comprises a filter element (102). 8.System (100) according to one of claims 1 to 7, wherein said first ultrasonic wave emitting element (170) is capable of covering an angular sector of the cylindrical portion (150) which comprises a filter element (102), thus covering an axial section of the cylindrical portion (150) and of the filter element (102).

9. System (100) according to one of claims 1 to 8, wherein each ultrasonic wave emitting element (170) is capable of emitting waves at a frequency of between 20 and 70 KHz, preferably between 20 and 40 KHz.

10. System (100) according to one of claims 1 to 9, wherein all the ultrasonic wave emitting elements (170) operate by emitting waves simultaneously.

11. System (100) according to one of claims 1 to 10, in which the ultrasonic wave emitting elements (170) operate intermittently.12.System (100) according to one of claims 1 to 11, in which each ultrasonic wave emitting element (170) comprises a metal box (171) capable of covering the section of said cylindrical portion (150), ultrasonic wave generating transducers (172) fixed on one of the walls of the metal box (171) in order to generate the ultrasonic waves from said wall (173) forming an emission wall, and a set of electric cables (172a) for powering the ultrasonic wave generating transducers (172).MROTE-4-PCT.

13. System (100) according to the preceding claim, in which said ultrasonic wave generating transducers (172) have a power greater than or equal to 0.5 W / cm 2.14.System (100) according to claim 12 or claim 13, wherein each metal box (171) is sealed.

15. System (100) according to the preceding claim, further comprising a pressurization circuit (180, 181) connected to each metal box (171) by a pressurized air supply line (181) and making it possible to generate in the box (171) an air pressure of a value greater than or equal to the difference between the pressure value of the water at the immersion location of said control system (100) and 0.3 bar.

16. System (100) according to one of claims 1 to 15, further comprising a physical or geometric barrier (140) comprising a radial wall in the form of a collar, located at a distance from the first ultrasonic barrier (110), on the side of the first ultrasonic barrier (110) from which the ultrasonic waves are emitted. 17.Suction strainer (103) intended to be immersed in water, for a water pumping system of a drinking or industrial water installation or of a thermal network installation with heat exchanger, said suction strainer comprising a frame (101) with a first tubular end intended to be connected to the inlet of a suction pipe (200) and a cylindrical portion (150) with an opening (151), and a system (100) according to any one of claims 1 to 16 equipping said cylindrical portion (150).

18. Suction strainer according to claim 17, wherein said opening is entirely covered by a filter element (102) or the cylindrical portion (150) comprises a filter element (102) with spaces forming said opening (151). 19.Heat exchanger intended to be immersed in water, comprising at least one mouth for sucking water towards an opening, said mouth forming a cylindrical portion (150) with an opening and being equipped with a system (100) according to any one of claims 1 to 16.MROTE-4-PCT.

20. Heat exchanger according to claim 19, wherein said opening is entirely covered with a filter element (102).

21. Installation comprising a pumping system with a part immersed in water comprising a cylindrical portion (150) with an opening allowing the entry of water, said cylindrical portion (150) being equipped with a system (100) according to any one of claims 1 to 16.

22. Installation according to claim 21, wherein said opening is entirely covered with a filter element (102).MROTE-4-PCT

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