Fluidic device for filtering a fluid and associated method

Abstract

Fluidic filtration device (1) adapted to filter a fluid of at least one particle (10), comprising at least one network (7) of microfluidic channels, said at least one network comprising:- a main inlet for fluid to be filtered (7.1);- a main outlet for particle concentrate (7.2);- a plurality of filtered fluid outlets (7.3);- a plurality of particle positioning channels (4);- a plurality of particle concentration channels (5);- a plurality of filtered fluid collection channels (6);- a hydrodynamic resistance balancing structure (11) configured such that the hydrodynamic resistance of each of the filtered fluid collection channels Ri is defined by a hydrodynamic resistance R1 of the balancing structure and a ratio a between the volume of filtered fluid and the volume of particle concentrate at the outlet of each particle concentration channel. Abstract figure: Figure 2

Description

Title of the invention: Fluidic device for filtering a fluid and associated method Technical field

[0001] The present invention relates to a fluidic device for filtering a fluid and an associated filtration method, for example used to filter water, solid pollutants such as plastic microparticles. Prior art

[0002] Plastic microparticles, called microplastics, are particles with a diameter of less than 5 mm. They can be divided into primary microplastics and secondary microplastics. Primary microplastics are manufactured to be microscopic in size, which refers to plastic particles directly added to products, including particles intended for the manufacture of plastic products, cosmetics and microbeads contained in household products. Secondary microplastics result from the fragmentation of large plastic waste by physical and / or chemical degradation.

[0003] The presence of microplastics in the environment has become a global environmental concern and a growing problem due to the exponential increase in plastic production. This has been growing worldwide since the development of the first synthetic polymers in the mid-20th century. The main consequence of the high production of plastics is the generation of large quantities of this waste that ends up in the environment, mainly in the marine environment. It is estimated that each year, between 4.8 and 12.7 million tons of plastic waste are introduced into the oceans, thus becoming a major environmental problem. Based on marine water samples collected, it is estimated that microplastics can represent up to 94% of plastic waste. Microplastics have been found in virtually all ecosystems, continental and oceanic waters, sediments, air and soils.Microplastics are also present in organisms, mainly aquatic organisms. Water pollution by microplastics is a major concern because of the potential harm they can cause to both humans and wildlife.

[0004] Currently, known methods for pre-treatment of microplastic samples include direct visual inspection, sieving, filtration and density flotation. There is currently no standardized method for separating microplastics from water with a high yield. Most These methods have some disadvantages such as the high cost of the equipment required, the long time required to carry out the separation of microplastics and the difficulty of scaling up the system on an industrial scale for the treatment of large volumes of water. Summary

[0005] The present disclosure improves the situation.

[0006] A fluidic filtration device is proposed, suitable for filtering a fluid of at least one particle, comprising at least one fluidic network of microfluidic channels, said at least one network comprising: - a main inlet for fluid to be filtered; - a main outlet for particle concentrate; - a plurality of filtered fluid outlets; - a plurality of particle positioning channels; - a plurality of particle concentration channels, each particle concentration channel extending in a direction of flow of the fluid to be filtered, each concentration channel comprising an inlet for fluid to be filtered, at least one outlet for filtered fluid and an outlet for particle concentrate, each particle positioning channel being in fluid communication with the inlet for fluid to be filtered of the particle concentration channel; - a plurality of filtered fluid collection channels, each filtered fluid collection channel extending from a particle concentration channel and being in fluid communication with the filtered fluid outlet of said particle concentration channel; - a hydrodynamic resistance balancing structure configured so that the hydrodynamic resistance of each of the filtered fluid collection channels R; is defined by a hydrodynamic resistance Ri carried by the balancing structure and a ratio a between the volume of filtered fluid and the volume of particle concentrate at the outlet of each of the particle concentration channels.

[0007] According to one embodiment, the balancing structure comprises the particle concentration channel having an outlet forming the main particle concentrate outlet of the network.

[0008] According to an advantageous embodiment, the balancing structure further comprises a plurality of balancing conduit segments of different dimensions so as to distribute the hydrodynamic resistance Ri over said particle concentration channel and all of the conduit segments.

[0009] Preferably, the balancing conduits are formed by one or more particle concentrate collection conduits and / or by at least one conduit arranged outside said at least one network.

[0010] According to another embodiment, at least one filtered fluid collection channel among the plurality of filtered fluid collection channels is extended by a plurality of hydrodynamic resistance distribution conduit segments of different dimensions so as to distribute its hydrodynamic resistance on the one hand over said at least one filtered fluid collection channel and on the other hand over said plurality of conduit segments.

[0011] Preferably, said conduits are formed by one or more filtered fluid collection conduits and / or by at least one conduit arranged outside said at least one network.

[0012] According to an exemplary embodiment, the hydrodynamic resistance Ri of the balancing structure is greater than the largest hydrodynamic resistance RCg among the RCg of the network by a factor of between 5 and 5,000,000, preferably between 500 and 100,000, the resistance RCG being the sum of the hydrodynamic resistances of the positioning channel and the adjacent particle concentration channel, the positioning channel being the channel preceding the concentration channel with respect to the direction of the fluid flow.

[0013] According to an exemplary embodiment, the filtered fluid collection channel has a width of between 0.1 pm and 1000 pm, a height of between 0.1 pm and 1000 pm and a length of between 10 pm and 100 mm.

[0014] According to one embodiment, said at least one network comprises: - a plurality of positioning channels; - a plurality of particle concentration channels each comprising an inlet for fluid to be filtered, two outlets for filtered fluid and an outlet for particle concentrate; - a plurality of filtered fluid collection channels extending on either side from the particle concentration channels and in fluid communication with the two filtered fluid outlets of the particle concentration channel.

[0015] According to another embodiment, said at least one network comprises: - a plurality of particle concentration channels extending in the direction of fluid flow and arranged parallel to each other, each of the particle concentration channels comprising an inlet, a particle concentrate outlet and a filtered fluid outlet; - a plurality of filtered fluid collection channels, each filtered fluid collection channel extending in the extension of a particle concentration channel and being in fluid communication with said particle concentration channel; - a plurality of positioning channels, each positioning channel fluidically connecting the particle concentrate outlet of a particle concentration channel with the particle concentrate inlet of the particle concentration channel. particle concentration following; - the length of each filtered fluid collection channel gradually decreasing in the direction from the main fluid inlet to the main particle concentrate outlet.

[0016] The features set out in the following paragraphs may, optionally, be implemented, independently of one another or in combination with one another:

[0017] The particle concentration channel comprises a plurality of surface modifiers of the inner wall of the particle concentration channel, said modifiers being configured to direct the flow of particles towards the particle concentrate outlet and the flow of the filtered fluid towards said at least one filtered fluid outlet of the particle concentration channel.

[0018] The positioning channel comprises a plurality of surface modifiers of the inner wall of the particle concentration channel, said modifiers being configured to direct the particle concentrate to a desired positioning relative to the inlet of fluid to be filtered of the particle concentration channel and / or align the particles according to the direction of flow of the fluid.

[0019] Surface modifiers include studs, chevrons and / or notches.

[0020] Said pads extend from a surface of the inner wall towards the opposite wall and / or to the surface of the opposite wall.

[0021] According to one embodiment, the device comprises a plurality of networks organized according to radial symmetry around a fluid distribution conduit to be filtered to form a microfluidic unit.

[0022] According to another embodiment, the device comprises a stack of layers, each layer comprising a plurality of microfluidic units, one end of the stack comprising a fluid distribution network and the other end of the stack comprising a filtered fluid collection network and a particle concentrate collection network, said conduit for distributing fluid to be filtered from each fluidic unit passing through the plurality of layers to supply the main inlet of fluid to be filtered from all the networks forming the microfluidic unit.

[0023] Preferably, said at least one network is sized so that at least 10% by mass of the particles having a volume between 4.1025 and 7.109 m3' present in the fluid to be filtered are collected at the main outlet of the particle concentrate (7.2) of the network.

[0024] According to another aspect, there is provided a filtration assembly adapted to filter a fluid of at least one particle, comprising a plurality of fluidic devices such as defined above, said networks being fluidically connected in series and / or in parallel.

[0025] According to one embodiment, the assembly comprises twenty fluidic devices, each of the devices forming a stack of a thousand layers having a diameter of 30 cm, each of the layers comprising sixty fluidic units, each of the units comprising sixteen networks organized according to a radial symmetry around a distribution conduit for fluid to be filtered capable of circulating with a flow rate of 100 mVs for a pressure of 10 bars.

[0026] According to another aspect, there is provided a filtration system comprising: - at least one filtration device as defined above; - a fluid temperature measuring system; - a fluid pH measuring system; - a geolocation system; - a leak or obstruction location system configured to generate an alarm signal in the event of a leak; - a pressure regulator; - a flow regulator; - an optical system configured to characterize the particles; - an ultrasonic radiation system to determine the nature of the polymer particles; - a servo system to stop the filtration device; - a pre-filtration system of the membrane filter or centrifugal filter type; - a particle treatment system using an enzymatic, chemical or physical method; - a wireless data transmission system.

[0027] According to yet another aspect, there is provided a filtration method adapted to filter a fluid of at least one particle by implementing the device as defined above, comprising: - passing the fluid through said at least one filtration network with a flow rate of the fluid to be filtered of between 0.01 m3 / s and 100 m3 / s; - ensure a pressure difference between the main inlet and the outlets of the device so as to drive said flow rate into said filtration device, the pressure difference being less than 10 bar; - said flow rate being such that the Péclet number of the particle in the flow of fluid traveling the length of said particle concentration channel in the direction of flow is between 1.102 and 1.1020.

[0028] According to one embodiment, the method further comprises a step in which a washing fluid is passed through the channels forming the microfluidic network. Brief description of the drawings

[0029] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig.l

[0030] [Fig.l] [Fig.l] schematically illustrates a filtration device according to an embodiment comprising a distribution network for fluid to be filtered, a fluid filtration network, a particle collection network and a filtered fluid collection network. Fig. 2

[0031] [Fig.2] [Fig.2] schematically illustrates a fluidic filtration network according to a embodiment. Fig. 3

[0032] [Fig.3] [Fig.3] schematically illustrates another representation of the network fluidic of [Fig.2] with the hydrodynamic resistances associated with each of the filtered fluid collection channels and the hydrodynamic resistance associated with the last particle concentrate collection channel at the network outlet. Fig. 4

[0033] [Fig.4] [Fig.4] schematically illustrates a microfluidic unit according to a mode embodiment comprising twelve fluidic networks of [Fig.2] arranged radially around a fluid distribution conduit to be filtered (a) and an enlarged top view of the central zone of the microfluidic unit (b). Fig. 5

[0034] [Fig.5] [Fig.5] schematically illustrates a filtration device according to another embodiment, comprising a stack of layers each comprising a plurality of fluidic units, a distribution network for fluid to be filtered positioned at one end of the stack, a filtered fluid collection network and a particle concentrate collection network being positioned at the opposite end of the stack. Fig. 6

[0035] [Fig.6] [Fig.6] schematically illustrates an enlarged view of the exit area of particle concentrate of the fluidic filtration network of [Fig.2] (a), a fluidic unit (b) and a stack of fluidic units fluidically connected to a particle concentrate collection network and a conduit external to the stack. Fig. 7A

[0036] [Fig.7A] [Fig.7A] shows a perspective and partially exploded view of a filtration device in which the stack of [Fig.5] is arranged in a housing according to one embodiment. Fig. 7B

[0037] [Fig.7B] [Fig.7B] shows a side view of [Fig.7A]. Fig. 8

[0038] [Fig.8] [Fig.8] schematically illustrates a filtration network according to another embodiment Fig. 9

[0039] [Fig.9] [Fig.9] shows a sectional view of a portion of the filtration network of the [Fig.2] with the presence of notches in the positioning channel, the presence of studs and notches in the particle concentration channel according to one embodiment. Fig. 10

[0040] [Fig. 10] [Fig. 10] schematically represents the different examples of embodiments of surface modifiers produced on the internal wall of the positioning channel and / or on the internal wall of the particle concentration channel. Fig. 11

[0041] [Fig. 11] [Fig. 11] schematically illustrates the general architecture of a filtration system. Fig. 12

[0042] [Fig. 12] [Fig. 12] schematically illustrates a network of fluidic filtration devices. Fig. 13

[0043] [Fig. 13] [Fig. 13] schematically illustrates a process for fluidic filtration of particles. Description of the embodiments

[0044] Definitions

[0045] For the purposes of the present disclosure, the term "particle" designates any rigid or soft solid element which may be a plastic, metallic, mineral particle or biological particle such as bacteria, human, animal, plant cell, plankton or virus. It may be in the form of a substantially spherical element, a fiber or a sheet. The element has a volume of less than 5 mm3.

[0046] The term "filter", in particular the term "filter a fluid of at least one particle", refers to the treatment making it possible to remove all or part of the particles present in the fluid to be filtered.

[0047] The term "length" of a channel refers to the size of a channel along the main direction of fluid flow.

[0048] The term “channel width” refers to the maximum size of a channel in a direction transverse to the main direction of flow of the fluid.

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] The term "channel height" refers to the minimum size of a channel in a direction transverse to the main direction of fluid flow. The term "particle concentrate" refers to a volume of liquid containing particles where the volume of the fluid has been divided by at least 1000 compared to the initial volume of the fluid. The term "filtered fluid" refers to a volume of liquid whose particle concentration is lower than the concentration of the concentrate. A filtered fluid may be entirely free of particles. A "two-dimensional network" refers to a network in which all of the elements can be distributed in a plane, but in a line. More particularly, a "two-dimensional network of channels" refers to a network of channels in which each channel is distributed in the same plane, regardless of the orientation of each channel. Preferably, the microfluidic channels of the network of the present disclosure form at least one two-dimensional network of channels. A three-dimensional network is a network in which all of its elements can be distributed in space, but not in a plane. More specifically, a three-dimensional network of channels is a network of channels in which each channel is distributed in space but not in a plane, regardless of the orientation of each channel. The term "hydrodynamic resistance" refers to the ratio between the upstream-downstream pressure difference in a channel or more generally a network of channels or a pipe, and between the volume flow rate of the fluid passing through the channel or more generally the network of channels or the pipe. The Péclet number Pe characterizes the ratio between the transport of a particle by convection and by diffusion, in a microfluidic channel. It is defined by the following relation (1): p„_Lc± Where Lc is the characteristic length of the microfluidic channel, and v is the advection velocity of the particle 10. When implementing the filtration device of the present disclosure, it is considered that the characteristic length is equal to the length of a microfluidic channel in the main direction of fluid flow. With reference to [Fig.l], the fluidic device 1 may comprise four fluidic networks 22, 7, 25, 26 fluidically connected together. The inlet 23 of the device 1 is connected to a fluid distribution network 22. The distribution fluidic network 22 is adapted to distribute the fluid to be filtered to the filtration fluidic network 7, to which it is fluidically connected. The filtration fluidic network 7 may be a two-dimensional network of microfluidic channels, as shown in [Fig. 2], [Fig. 8] or a three-dimensional network of microfluidic channels, as shown in [Fig. 5]. The fluid connection between the filtered fluid distribution network 22 and the filtration network 7 can be implemented, for example, by a plurality of conduits connected to a plurality of inlets of the filtration fluid network. The filtration fluid network 7 is connected upstream to the filtered fluid collection fluid network 26 and to the particle concentrate collection fluid network 25. The fluid connection between the fluid filtration network 7 and the filtered fluid collection network can be implemented, for example, by a plurality of filtered fluid outlets of the filtration network connected to a plurality of inlets of the filtered fluid collection network.The fluid connection between the fluid filtration network 7 and the particle concentrate collection network 25 can be implemented by a plurality of particle concentrate outlets connected to a plurality of inlets of the particle collection network. The filtered fluid collection network 26 is connected upstream to the filtered fluid outlet 28. The particle collection network 25 is connected upstream to the particle outlet 27.

[0059] With reference to [Fig. 2], an embodiment of the network 7 of microfluidic channels suitable for filtering a fluid of at least one particle is shown. [Fig. 2] schematically illustrates a top view of a set of microfluidic channels. The network comprises a main inlet for fluid to be filtered 7.1, a main outlet for particle concentrate 7.2 and a plurality of outlets for filtered fluid 7.3.

[0060] The microfluidic channel network 7 comprises three categories of channels according to their function in implementing fluid filtration. The network comprises a plurality of particle positioning channels 4, a plurality of particle concentration channels 5 and a plurality of filtered fluid collection channels 6. The particle concentration channels 5 and the filtered fluid collection channels 6 extend along a main direction of fluid flow. More specifically, the particle concentration channels 5 extend along the main direction of fluid flow and are arranged parallel to each other. Each filtered fluid collection channel 6 extends in the extension of a particle concentration channel and is in fluid communication with the particle concentration channel. The length of each filtered fluid collection channel gradually decreases in the direction of the main fluid inlet 7.1 to the main outlet 7.2 of particle concentrate. The example of the network shown in [Fig.2] here comprises nine positioning channels 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, nine particle concentration channels 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9 and eight filtered fluid collection channels 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8. The number of channels forming the microfluidic network is not limiting.

[0061] Each positioning channel comprises an inlet for fluid to be filtered 13E and an outlet for fluid to be filtered 13S. In [Fig. 2], the inlet 13E and the outlet 13S are shown only on the first positioning channel 4.1. For the purposes of the present disclosure, the term "first" designates the rank of the channel relative to the main inlet for the fluid to be filtered of the network. The inlet 13E of this first positioning channel is connected downstream to the outlet for fluid to be filtered of a distribution conduit for fluid to be filtered 2. The inlet 13E of this first positioning channel thus also forms the main inlet for fluid to be filtered 7.1 of the network.

[0062] Each concentration channel comprises a filter fluid inlet 14E and two outlets, a first filtered fluid outlet 14S.1 and a second particle concentrate outlet 14S.2. Each filtered fluid collection channel also comprises a filtered fluid inlet 9E and a filtered fluid outlet 9S. Each particle concentration channel is connected downstream with respect to the fluid flow direction to the filter fluid outlet of the positioning channel. In [Fig.2], the fluid inlet 14E of the particle concentration channel 5.1 is in fluid communication with the fluid outlet 13S of the positioning channel 4.1. The first filtered fluid outlet 14S.1 of the particle concentration channel 5.1 is in fluid communication with the filtered fluid inlet 9E of the filtered fluid collection channel 6.1. The second particle concentrate outlet 14S.2 of the particle concentration channel 5.1 is connected upstream to the inlet of the fluid to be filtered of the positioning channel referenced 4.2. In [Fig.2], the particles 10 are represented by white dots and flow from the main inlet 7.1 of the network to the main outlet of particle concentrate 7.2. Thus, the fluid to be filtered is filtered by flowing successively through the particle concentration channels which retain the particles. As a result, the particle concentration increases as the fluid flows through the particle concentration channels. In the example of [Fig.2], the outlet of the last particle concentration channel 5.9 forms the main outlet of particle concentrate 7.2 which is connected upstream to the inlet of a particle collecting conduit 3. The filtered fluid at the outlet of each filtered fluid collection channel 6 is collected by a filtered fluid collection channel 8. .

[0063] According to the present disclosure, it is desirable to be able to control the ratio between the volume of filtered fluid collected by the filtered fluid collection channel and the volume of particle concentrate at the outlet of each particle concentration channel, regardless of the geometry and characteristics of the positioning channels and particle concentration channels. Furthermore, it is essential that the microfluidic filtration network ensures that maximum particles flow to the particle concentration channel. According to the present disclosure, the control of the distribution of the volume of filtered fluid and the particle path can be achieved by balancing the hydrodynamic resistances carried by the structure of the network, and in particular carried by each of the channels forming the network.

[0064] With reference to [Fig.3] which illustrates a filtration network which comprises N channels for collecting filtered fluid, the hydrodynamic resistance ReqN of all the channels forming the network can be defined by the following relation (2):

[0065] R +a N ' 2 Ri

[0066] RCg is the sum of the hydrodynamic resistances of the positioning channel (Rc) and the particle concentration channel (RG), the positioning channel being the channel preceding the concentration channel with respect to the direction of fluid flow. Thus in [Fig.2] for example, RCG is the sum of the resistances of the positioning channel 4.1 and the concentration channel 5.1. RCG changes depending on the geometry and characteristics of the positioning channels and the concentration channels as well as the Reynolds number in the channels. The parameter a is the ratio between the volume of the particle concentrate Q at the outlet of the particle concentration channel and the volume of the filtered fluid at the outlet of the particle concentration channel Qout. Ri is the resistance carried by the last particle concentration channel carrying the main particle concentrate outlet. In [Fig.2], the last particle concentration channel which carries the resistance Ri is referenced 5.9. .

[0067] The inventors of the present invention have determined from relation (2) that when Ri is greater than the largest RCG resistance among the RCGs in the network by a certain factor, the distribution a does not change regardless of the RCG resistance, especially when Ri is greater than RCG by a factor between 5 and 5,000,000, preferably between 500 and 100,000. In the case where the network comprises different RCGs, they determined that Ri must be greater than the largest RCG resistance. In this way, the RCG resistance is made negligible compared to the resistance Ri in relation (2).

[0068] In order to be able to satisfy this condition, the filtration network of the present disclosure comprises a balancing structure 11 which extends from the particle concentration channel which carries the resistance Rb. In the exemplary embodiment shown in [Fig. 2], this balancing structure extends in the form of a channel from the main concentrate outlet of the particle concentration channel referenced 5.9. The balancing structure 11 is connected downstream to the particle concentrate outlet of the particle concentration channel 5.9 and upstream to the particle concentrate collection conduit 3. The resistance Ri is thus distributed on the one hand over the particle concentration channel 5.9 and over the channel forming the balancing structure 11. In the example of [Fig. 2], the outlet of the balancing structure 11 forms the main outlet of the particle concentrate 7.2. It is possible to adjust the dimension of this balancing structure in order to be able to define a resistance Ri large enough to make the resistance RCg- negligible

[0069] The hydrodynamic resistance of each of the filtered fluid collection channels is defined by the following relation (3):

[0070] „ 1 / p V nk,ni-^ \ ~ \ ^CG k =ia + ai /

[0071] Where R; is the hydrodynamic resistance of the filtered fluid collection channel, i being an integer between 2 and N. It follows from relation (2) that it is also possible to determine the resistance of each of the filtered fluid collection channels by defining a resistance Ri greater than Rœ so that the resistance R; is a function only of the distribution a and Ri. Thus, from these resistances R;, it is therefore possible to construct a stable microfluidic filtration network.

[0072] With reference to [Fig. 4], a radial architecture can be used to arrange a plurality of microfluidic networks around a conduit 2 for distributing fluid to be filtered. In the example of [Fig. 4], it is thus possible to arrange sixteen microfluidic networks 7 of [Fig. 2] around the primary channel 12. This architecture thus forms a microfluidic unit 30. The conduit 2 is fluidically connected to all of the inlets of the networks, thus making it possible to distribute fluid to be filtered to all of the sixteen networks as shown in the enlarged view of the central zone of the microfluidic unit. The filtered fluid collection outlets 9 of the sixteen networks can be fluidically connected together to at least one filtered fluid collection conduit 8. The particle concentrate outlets of the networks can be fluidically connected together to at least one particle concentrate collection conduit 3.This radial architecture makes it possible to maximize the surface density occupied by the filtration networks on a layer.

[0073] With reference to [Fig. 5], it is also possible to form a plurality of microfluidic units 30 in a single layer 31. In [Fig. 5], each layer 31 comprises, for example, six microfluidic units. The layers can also be stacked on top of each other. [Fig. 5] illustrates a stack 16 of twenty-two layers, each comprising six microfluidic units.

[0074] The distribution conduits 2 for the fluid to be filtered successively pass through the layers to distribute the fluid to be filtered to the different networks. The particle concentrate collection conduits 3 and the filtered fluid collection conduits 8 successively pass through the layers to collect the particle concentrate from each layer and the filtered fluid from each layer respectively.

[0075] The stack of layers 16 may comprise a network of distribution channels for fluid to be filtered 22, a network for collecting particle concentrate 25 and a network of filtered fluid collection 26. These networks may be in the form of layers of channels positioned at the ends of the stack. Thus, the first layer of the stack forms a network of fluid distribution channels and the last two layers of the stack respectively form a filtered fluid collection network and a particle collection network. The network of distribution channels for fluid to be filtered makes it possible to connect an inlet conduit for fluid to be filtered 23 to the distribution conduits 2 passing through the stack. The network of particle concentrate collection channels 25 makes it possible to connect a particle concentrate collection conduit 27 to the concentrate collection channels 3 successively passing through the stack. The network of filtered fluid collection channels 26 makes it possible to connect a filtered fluid collection conduit 28 to the filtered fluid collection channels 8 successively passing through the stack.

[0076] With reference to [Fig. 6] and as indicated above, the balancing structure 11 of the hydrodynamic resistances has the function of balancing the hydrodynamic resistances of all the microfluidic channels of the network 7. It is arranged in the extension of the last particle concentration channel with respect to the direction of the fluid flow. This last particle concentration channel thus also forms a particle concentrate collection channel whose outlet also forms the main outlet of the particle concentrate of the network 7.2. As illustrated by the example network of [Fig. 2] and the image (a) of [Fig. 6] which represents an enlarged view of this outlet zone of the particle concentrate of [Fig. 2], the balancing structure 11 extends from the last particle concentration channel referenced 5.9. In [Fig.6], part of this balancing structure is shown in the form of a channel.The hydrodynamic resistance Ri is thus distributed on the one hand over the channel 5.9 and on the other hand over the balancing structure 11. .

[0077] According to the present disclosure, it is possible to adjust the dimension of this balancing structure as a function of the hydrodynamic resistance Ri required to counterbalance the resistance RCg- According to an exemplary embodiment, the balancing structure comprises a plurality of balancing conduit segments of different dimensions so as to be able to distribute the hydrodynamic resistance Ri over all of the conduit segments.

[0078] According to an exemplary embodiment and as illustrated by image (b) of [Fig.6], a portion of the balancing conduits are advantageously formed by a particle concentrate collection conduit 3 connected downstream to the main particle concentrate outlet 7.2 of the network. Thus, the hydrodynamic resistance Ri is distributed over the particle concentrate collection channel 5.9 and the particle concentrate collection conduit 3.

[0079] According to another example and as illustrated by image (c) of [Fig.6], a part of the conduits of the balancing structure is also formed by the conduits of the particle concentrate collection network 25 which is located at the end of the stack 16. Thus, the hydrodynamic resistance Ri is distributed over the particle concentrate collection channel 5.9, the particle concentrate collection conduit 3 and the particle concentrate collection network 25.

[0080] According to yet another example, a part of the conduits of the balancing structure is formed by a conduit 29 arranged outside the network. The hydrodynamic resistance Ri is in this case distributed over the particle concentrate collection channel 5.9, the particle concentrate collection conduit 3, the particle concentrate collection network 25 and the conduit 29.

[0081] According to an exemplary embodiment, to overcome the technical constraints of microfabrication and in order to satisfy the hydrodynamic resistances R; calculated for the different filtered fluid collection channels, it is also possible to extend the filtered fluid collection channels of the conduit segments of different dimensions so as to be able to distribute the resistance over the corresponding fluid collection channel and one or more conduit segments. These conduit segments may be present and form part of the network 7. By way of example, a portion of these conduits are in particular formed by the filtered fluid collection conduit passing through the stack and / or by the filtered fluid collection conduit(s) of the network 26 located at the end of the stack 16. According to a variant, these segments may be formed by pipes arranged outside the network 7, as in the example illustrated in image (c) of [Fig.6].

[0082] Generally, the cross-sectional shape of a positioning channel, a particle concentration channel, and a filtered fluid collection channel may be circular, rectangular, or any other geometric shape.

[0083] The length of a filtered fluid collection channel may be between 0.01 mm and 100 mm, preferably between 0.1 mm and 50 mm and preferably between 1 mm and 20 mm. The width of a filtered fluid collection channel may be between 0.1 pm and 2000 pm, preferably between 5 pm and 1000 pm and preferably between 100 pm and 500 pm. The height of the filtered fluid collection channel may be between 0.1 pm and 2000 pm, preferably between 5 pm and 1000 pm and preferably between 100 pm and 500 pm. Generally, a microfluidic channel may have several heights.

[0084] The length of a particle concentration channel may be between 10 and 10,000 pm, preferably between 50 pm and 1,000 pm and preferably between 200 and 500 pm. The width of the particle concentration channel may be between 50 and 10,000 pm, preferably between 100 pm and 5,000 pm and preferably between 500 pm and 1,200 pm. The height of the particle concentration channel may be between 50 and 10,000 pm, preferably between 100 pm and 5,000 pm and preferably between 400 pm and 800 pm.

[0085] The length of a positioning channel may be between 10 and 10,000 pm, preferably between 50 pm and 1,000 pm and preferably between 200 pm and 500 pm. The width of the positioning channel may be between 50 pm and 10,000 pm, preferably between 100 pm and 5,000 pm and preferably between 500 pm and 1,200 pm. The height of the positioning channel may be between 50 and 10,000 pm, preferably between 100 pm and 5,000 pm and preferably between 400 pm and 800 pm.

[0086] Generally, microfluidic channels can be made of PDMS, PFPE, or any other known material suitable for microfabrication of microfluidic channels. Microfabrication techniques can be printing by UV lithography or 3D printing technologies to produce the patterns.

[0087] With reference to Figures 7A and 7B, the stack 16 of [Fig. 5] can be positioned inside a housing. The housing comprises a receptacle 32 in which the stack 16 is positioned and a cap 35 which is intended to close the receptacle 32. The cap comprises a connector 33 for distributing fluid to be filtered connected to the inlet conduit for fluid to be filtered of the stack. The receptacle 32 comprises an outlet connector 34 for filtered fluid connected to the filtered fluid collection conduit 28 of the stack 16. The receptacle 32 comprises a concentrate outlet connector 35 connected to the filtered fluid collection conduit 27 of the stack.

[0088] With reference to [Fig.8], another geometric shape of the microfluidic filtration network is illustrated. The microfluidic channel network 100 also comprises three categories of channels according to their function in implementing fluid filtration. The network 100 comprises a plurality of positioning channels 104.1, 104.2, 104.3, 104.4, 104.5, 104.6, 104.7, 104.8, 104.9, a plurality of particle concentration channels 105.1, 105.2, 105.3, 105.4, 105.5, 105.6, 105.7, 105.8, 105.9, 105.10 and a plurality of filtered fluid collection channels 106.1, 106.2, 106.3, 106.4, 106.5, 106.6, 106.7, 106.8, 106.9, 106.10. The network comprises a main fluid inlet 100.1, a main particle concentrate outlet 100.2, and a plurality of filtered fluid outlets 100.3, 100.4. The example of the network shown in [Fig.8] here includes nine positioning channels, ten particle concentration channels and twenty filtered fluid collection channels. The number of channels forming the microfluidic network is not limiting.

[0089] The concentration channels 105 extend along a main direction of fluid flow and are arranged one after the other. Each of the filtered fluid collection channels 106 extends from a particle concentration channel and is in fluid communication with the particle concentration channel.

[0090] Each positioning channel comprises a filter fluid inlet and a filter fluid outlet. In [Fig.8], the inlet 113E and the outlet 113S are shown only on the first positioning channel 104.1. The inlet 113E of this first positioning channel is connected downstream to the filter fluid outlet of a filter fluid distribution conduit 102. The inlet 113E of this first positioning channel thus forms the main filter fluid inlet 100.1 of the network. Each concentration channel comprises a filter fluid inlet 114E and three outlets, two filtered fluid outlets 114S.1, 114S.2, a third particle concentrate outlet 114S.3. Each filtered fluid collection channel also comprises a filter fluid inlet 109E and a filtered fluid outlet 109S.Each particle concentration channel is connected downstream with respect to the direction of fluid flow to the fluid outlet to be filtered of the positioning channel. In [Fig. 8], the fluid inlet 114E of the particle concentration channel 105.1 is in fluid communication with the fluid outlet 113S of the positioning channel 104.1. The first filtered fluid outlet 114S. 1 of the particle concentration channel 105.1 is in fluid communication with the filtered fluid inlet 109E of the filtered fluid collection channel 106.1. The second filtered fluid outlet 114S.2 of the particle concentration channel 105.1 is in fluid communication with the filtered fluid inlet 109E of another filtered fluid collection channel. The third particle concentrate outlet 114S.3 of the particle concentration channel is connected upstream to the filter fluid inlet of the next positioning channel referenced 104.2. In [Fig.8], the particles 10 are represented by white dots and flow from the main inlet 100.1 of the network to the main particle concentrate outlet 100.2. Thus, the fluid to be filtered is filtered by flowing successively through the positioning channels and the particle concentration channels which retain the particles. In the example of [Fig.8], the outlet of the last particle concentration channel 105.10 forms the main particle concentrate outlet 100.2 which is connected upstream to the inlet of a particle collecting conduit 103. The filtered fluid at the outlet of each filtered fluid collection channel 106 is collected by two filtered fluid collection channels 108.1, 108.2. .

[0091] In the example illustrated in [Fig.8], the network further comprises a hydrodynamic resistance stabilization structure 111 which extends from the last particle concentration channel 105.10. This structure 111 is configured so as to counterbalance the hydrodynamic resistances of the microfluidic channels of the network, in other words to make the resistance Rœ negligible compared to the resistance Rb. Thus the shape of the internal wall of the positioning channel and of the particle concentration channel does not cause the Reynolds number to vary.

[0092] With reference to [Fig.9], the internal walls of the positioning channels and the Concentration channels are structured and modified to increase filtration efficiency. These modifications were made possible by the presence of the stabilizing structure.

[0093] According to an exemplary embodiment, the inner wall of the particle concentration channel may comprise a plurality of modifiers which are configured to direct the flow of particles towards the particle concentrate outlet and the flow of filtered fluid towards the filtered fluid outlet.

[0094] According to another exemplary embodiment, the inner wall of the positioning channel comprises a plurality of modifiers which are configured to direct the particle concentrate to a desired positioning relative to the inlet of the particle concentration channel and / or align the particles according to the direction of flow of the fluid.

[0095] In [Fig.9], the positioning channel 4.2 comprises surface modifiers in the form for example of notches 40 and studs 42 which make it possible to direct the flow of particles towards the inlet of the particle concentration channel 5.2. The concentration channel 5.1 comprises for example studs 41 which are arranged so as to prevent the particles from heading towards the filtered fluid inlet of the filtered fluid collection channel 6.1.

[0096] The shapes of the surface modifiers are not limiting. They may include studs, chevrons and / or notches. According to an exemplary embodiment, the studs extend from a surface of the inner wall towards the opposite wall and / or to the surface of the opposite wall.

[0097] Preferably, the pads have a height of between 50 and 500 pm and are spaced apart by a distance of between 10 and 500 pm. According to an exemplary embodiment, the pads may have a height substantially equal to the height of the channel. According to another exemplary embodiment, the pads may be a partial height of the channel.

[0098] Preferably, the notches have a dimension of between 10 and 250 pm and are spaced apart by a distance of between 10 and 500 pm.

[0099] [Fig. 10] schematically illustrates the different possible examples of modi surface finishers, in the form of studs, notches or chevrons.

[0100] Preferably, the network is sized so that at least 10% by mass of the particles having a volume between 4.1025 and 7.109 m3' present in the fluid to be filtered are collected at the outlet of the particle concentrate.

[0101] [Fig. 11] schematically illustrates the general architecture of a system of filtration. The system 300 comprises a frame 69, which comprises at least one fluidic filtration device 1. The system may comprise, downstream of the filtration device 1, an ultrasonic radiation system for determining the nature of the polymer of the particles 49, 51 and an optical system 50 configured to characterize the particles present in the fluid at the outlet of the filtration device 1. Upstream of the filtration device 1, the filtration system comprises a temperature measurement system 47 which makes it possible to measure the temperature of the fluid, a geolocation system 48 which makes it possible to locate the filtration device when it is implemented in a natural environment, a fluid pH measurement system 56, a flow regulator 55 which makes it possible to control the flow rate of the fluid in the filtration system and a pressure regulator 57. The flow regulator 55 makes it possible to adjust the flow rate so as to cause a flow rate of fluid in the filtration system of between 0.1 L.min 1 and 18 L.min *.

[0102] The pressure regulator 57 can control a fluid flow rate by pressure difference inside the fluidic device. Upstream of the inlet of fluid to be filtered from the device, the system comprises a pre-filtration system of the membrane filter or centrifugal filter type 42 so as to leave only particles having a diameter suitable for being filtered in the filtration device.

[0103] The different arrows illustrate the direction of possible fluid flows in the system.

[0104] Advantageously, the system comprises a particle treatment system 43 located at the outlet of the filtration device in order to treat the particles with an enzymatic solution for example.

[0105] Advantageously, the system comprises a selection valve 53 at the inlet and a selection valve 54 at the outlet. The selection valve 53 makes it possible to control the inlet of fluid to be filtered 60, the inlet of acid / enzymatic solution 61 and the washing outlet 62. The selection valve 54 makes it possible to control the outlet of particles 63, the outlet of acid / enzymatic solution 64, the inlet of the washing fluid 65, the outlet of filtered fluid 66, the outlet of acid / enzymatic solution 67 and the inlet of the washing fluid 68. The two selection valves 53, 54 are adapted to redirect the different fluids upstream and downstream of the fluidic device 1 to allow recirculation of the fluid.

[0106] Advantageously, the system comprises a servo system 52 which makes it possible to stop the filtration if necessary.

[0107] The system comprises a control unit which is electrically connected to the flow regulator, the pressure regulator, the selection valves. The control unit may be, for example, a computer comprising a microprocessor, a memory and a display unit. Data communications between the control unit and the components of the filtration system may be implemented by a wireless data transmission system. The data allows closed-loop control of the recirculations of the fluids in the system.

[0108] With reference to [Fig. 12], a filtration assembly may comprise several devices positive fluidic devices 1. The different fluidic devices 1 can be arranged in parallel, as illustrated in [Fig. 12]. The assembly can treat a fluid at a higher flow rate than a system comprising a single fluidic device 1. In an embodiment not illustrated, different fluidic devices can be connected in series. An assembly can comprise for example between two and twenty fluidic devices, preferably between three and ten fluidic devices.

[0109] [Fig. 12] schematically illustrates a system comprising eight fluidic devices fluidically connected in parallel. A fluid to be filtered comprising particles is introduced at the inlet of the system 36. A network of fluidic connectors connects the inlet 36 to each of the inlets of the devices 1. The filtered fluid is collected at the outlet of the devices. A network of fluidic connectors makes it possible to connect each of the filtered fluid outlets of the devices to the outlet 37. The particle concentrate is collected at the outlet of the devices. A network of fluidic connectors makes it possible to connect each of the particle concentrate outlets of the devices to the outlet 38.

[0110] According to an exemplary embodiment, the filtration assembly may comprise twenty fluidic devices which are connected together in parallel or in series. Each device comprises one thousand fluidic layers which have a diameter of 30 cm which can operate with an inlet pressure of 1 bar and with a flow rate of 1 m3 / s. Each layer comprises sixty fluidic units. Each unit comprising sixteen networks. Such a fluidic assembly can treat a fluid with a flow rate of 100 m3 / s for a pressure of 10 bars.

[0111] With reference to [Fig. 13], the method 200 for filtering a fluid comprising particles may comprise several steps.

[0112] In a step 201, a fluid is passed through a network of microfluidic channels 7 at a flow rate of the fluid to be filtered. The speed of the fluid flow or its flow rate can be controlled by a pressure regulator. The value of the flow rate can be calculated as a function of the geometry of the different channels of the network and as a function of the applied pressure. Thus, a fluid flow is controlled whose flow rate of the fluid to be filtered is between ImVs to 100 m3 / s. The flow rate is chosen so that the Péclet number of the particle in the flow of the fluid traveling the length of said particle concentration channel in the direction of flow is between 27.102 and 25.1020. In step 201, a pressure difference of less than 10 bars between the main inlet and the outlets of the device is controlled so as to cause an appropriate flow rate in said filtration device.

[0113] During a step 202, the washing of the microfluidic channels is controlled as described above. This step can be followed by a step 201. Thus, it is possible to filter a high volume of fluid, by interrupting the flow of fluid by washing.

[0114] During a step 203, the fluid is recirculated. Step 203 can be carried out in parallel to step 201. Recirculation can be implemented by recirculating the fluid in the same direction as during the first circulation of the fluid, or in the opposite direction.

[0115] Filtration example

[0116] The concentration of microparticles in a volume of water in a fluidic concentration device has been implemented.

[0117] In order to circulate a volume of 10 L / min in a device comprising 480 fluidic filtration devices while limiting the pressure loss to 0.2 bar, the general hydraulic resistance of each device must not exceed 2.8el 1 Pa.s / m3.

[0118] A study of the a distribution that splits the incoming fluid volume into filtered fluid and fluid with microparticle, depending on the addition of surface modifier was established. The a distribution corresponds to the ratio between the volume of filtered fluid at the outlet of the particle concentration channel and the volume of particle concentrate at the outlet of the particle concentration channel. Devices with channels with geometries such as Ri / RCg < 100 and Ri / RCg > 100 were defined. In these channels, one or two surface modifiers, stud-shaped and notch-shaped, were then added. When Ri / RCg < 100, the variations of the a distribution at each branch fluctuate enormously, presenting a standard deviation of 236%, whereas when Ri / RCg > 100, this standard deviation is only 25%.

[0119] A circulation of fluid + microparticles, with a concentration of 100 microparticles per mL, was observed in a device comprising eight filtered fluid collection channels, nine positioning channels and nine concentration channels, the last of which is a concentrate collection channel referenced 5.9 in [Fig.2] comprising the main particle concentrate outlet, the imposed flow being 10.31 mL / min (speed 1.2m / s). In the concentration channels, three pillars of 50 microns in diameter, crossing the entire channel, were arranged with a distance of 50 microns between each. Spherical particles with dimensions greater than 150 microns were correctly conveyed to the microparticle collection channel at 100%, while particles with dimensions less than 150 microns were not correctly conveyed at 75%.It was observed that the positioning of small diameter particles at the inlet of the concentration channel played a crucial role for the proper functioning of the device. When a matrix of dots was added in the positioning channel, particles with diameters between 50 and 150 microns were correctly directed to the concentrate collection channel. When circulating particles of the same volume, but different shapes (spheres, fibers or sheets), it was observed that the surface modifier arrangements that allowed the delivery of spherical particles to the microparticle collection channel did not allow the delivery of microparticles of . same volume but different shape. Thus, it was observed that the routing was dependent on the Péclet number of the microparticle, this being linked to the volume of the particles.

[0120] [Tables 1] Shape Sphere A Sphere B Fiber A Dimensions Diameter (m) lOOxlO6 Diameter (m) 57.3 xlO 6 Diameter (m) 50xlO6 Length (m) lOOxlO6 Diffusion coefficient (m2 / s) 4.42 xlO 15 6.13x10 15 6.13x10 15 Péclet number 2.71 xlO10 1.41 xlO10 1.41 xlO10

[0121] The results show that the particles in the form of fibers have rotational movements that made it more difficult to transport them to the microparticle collection channel. These rotational movements are minimized by the presence of a network of pads arranged in the positioning channel. The pads were thus able to orient the fibers in alignment with the fluid flow.

Claims

Claims

1. Fluidic filtration device (1) adapted to filter a fluid of at least one particle (10), comprising at least one fluidic network (7) of microfluidic channels, said at least one network (7) comprising: - a main inlet for fluid to be filtered (7.1) connected to a fluidic distribution network for fluid to be filtered (22); - a main particle concentrate outlet (7.2) connected to a particle concentrate collection network (25); - a plurality of filtered fluid outlets (7.3) connected to a filtered fluid collection network (26); - a plurality of particle positioning channels (4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9), each particle positioning channel comprising an inlet for fluid to be filtered and an outlet for fluid to be filtered, the inlet of the first positioning channel among the plurality of positioning channels forming the main inlet for fluid to be filtered; - a plurality of particle concentration channels (5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9), each particle concentration channel extending along a direction of flow of the fluid to be filtered, each concentration channel comprising an inlet for fluid to be filtered (14E), at least one outlet for filtered fluid (14S.1) and a particle concentrate outlet (14S.2), the particle concentrate outlet of the last particle concentration channel among the plurality of particle concentration channels forming the main particle compact outlet and the particle concentrate outlet of the other particle concentration channels being in fluid communication with the inlet for fluid to be filtered of the positioning channel, the fluid outlet of each particle positioning channel being in fluid communication with the inlet for fluid to be filtered of the particle concentration channel; - a plurality of filtered fluid collection channels (6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8), each filtered fluid collection channel extending from a particle concentration channel and being in fluid communication with the filtered fluid outlet (14S.1) of said particle concentration channel; - each particle concentration channel comprising surface modifiers (42) arranged at its filtered fluid outlet so as to prevent particles from moving towards the collection channel of filtered fluid; - a hydrodynamic resistance balancing structure (11) configured so that the hydrodynamic resistance of each of the filtered fluid collection channels R; is a function only of the hydrodynamic resistance Ri and of the ratio a between the volume of filtered fluid and the volume of particle concentrate at the outlet of each of the particle concentration channels, said balancing structure (11) extending in the form of a channel from the main particle concentrate outlet (7.2, 100.2) of the particle concentration channel (5.9, 105.10).

2. Device according to claim 1, wherein the balancing structure (11) further comprises a plurality of balancing conduit segments of different dimensions so as to distribute the hydrodynamic resistance Ri over said particle concentration channel (5.9, 105.10) and all of the conduit segments.

3. Device according to claim 2, in which the balancing conduits are formed by one or more particle concentrate collection conduits (3, 103)

4. Device according to one of claims 1 to 3, wherein at least one filtered fluid collection channel among the plurality of filtered fluid collection channels (6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8) is extended by a plurality of hydrodynamic resistance distribution conduit segments of different dimensions so as to distribute its hydrodynamic resistance on the one hand over said at least one filtered fluid collection channel and on the other hand over said plurality of conduit segments.

5. Device according to claim 4, wherein said conduits are formed by one or more filtered fluid collection conduits (8) and / or by at least one conduit arranged outside said at least one network.

6. Device according to one of claims 1 to 5, in which the hydrodynamic resistance Ri of the balancing structure (11) is greater than the largest hydrodynamic resistance RCg among the RCg of the network by a factor of between 5 and 5,000,000, preferably between 500 and 100,000, the resistance RCG being the sum of the hydrodynamic resistances of the positioning channel and the adjacent particle concentration channel, the positioning channel being the channel preceding the concentration channel with respect to the direction of fluid flow.

7. Device according to one of claims 1 to 6, in which the channel of filtered fluid collection has a width between 0.1 pm and 1000 pm, a height between 0.1 pm and 1000 pm and a length between 10 pm and 100 mm.

8. Device according to one of claims 1 to 7, wherein said at least one network (100) comprises: - a plurality of positioning channels (104.1, 104.2, 104.3, 104.4, 104.5, 104.6, 104.7, 104.7, 104.8, 104.9); - a plurality of particle concentration channels (105.1, 105.2, 105.3, 105.4, 105.5, 105.6, 105.7, 105.7, 105.8, 105.9, 105.10) each comprising an inlet for fluid to be filtered (114E), two outlets for filtered fluid (114S.1, 114S.2) and an outlet for particle concentrate (114S.3); - a plurality of filtered fluid collection channels (106.1, 106.2, 106.3, 106.4, 106.5, 106.6, 106.7, 106.7, 106.8, 106.9, 106.10) extending on either side from the particle concentration channels and in fluid communication with the two filtered fluid outlets (114S.1, 114S.2) of the particle concentration channel.

9. Device according to one of claims 1 to 7, wherein said at least one network (7) comprises: - a plurality of particle concentration channels (5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9) extending in the direction of the fluid flow and arranged parallel to each other, each of the particle concentration channels comprising an inlet (14E), a particle concentrate outlet (14S.2) and a filtered fluid outlet (14S.1); - a plurality of filtered fluid collection channels (6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8), each filtered fluid collection channel extending in the extension of a particle concentration channel and being in fluid communication with said particle concentration channel; - a plurality of positioning channels (4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9), each positioning channel fluidically connecting the particle concentrate outlet of a particle concentration channel with the particle concentrate inlet of the next particle concentration channel; - the length of each filtered fluid collection channel gradually decreasing in the direction from the main fluid inlet (7.1) towards the main particle concentrate outlet (7.2).

10. Device according to one of claims 1 to 9, in which the channel of positioning comprises a plurality of surface modifiers (40, 41, 42), said modifiers being configured to direct the particle concentrate to a desired positioning relative to the fluid inlet to be filtered of the particle concentration channel and / or align the particles according to the direction of flow of the fluid.

11. A device according to claim 10, wherein the surface modifiers comprise studs (42), chevrons and / or notches (41).

12. A device according to claim 11 wherein said studs extend from a surface of the inner wall towards the opposite wall and / or to the surface of the opposite wall.

13. Device according to one of claims 1 to 12, comprising a plurality of networks (7, 100) organized according to a radial symmetry around a conduit (2) for distributing fluid to be filtered to form a microfluidic unit (30).

14. Device according to claim 13, comprising a stack of layers (16) each comprising a plurality of microfluidic units (30), one end of the stack comprising a fluid distribution network (22) and the other end of the stack comprising a filtered fluid collection network (26) and a particle concentrate collection network (25), said distribution conduit for fluid to be filtered (2) of each fluidic unit passing through the plurality of layers to supply the main inlet of fluid to be filtered of all the networks forming the microfluidic unit.

15. Device according to one of claims 1 to 14, in which said at least one network is sized so that at least 10% by mass of the particles having a volume between 4.1025 and 7.109 m3' present in the fluid to be filtered are collected at the outlet of the particle concentrate.

16. Filtration assembly adapted to filter a fluid of at least one particle, comprising a plurality of fluidic devices (1) according to one of claims 1 to 15, said networks being fluidically connected in series and / or in parallel.

17. An assembly according to claim 16, comprising twenty fluidic devices (1), each of the devices forming a stack of a thousand layers having a diameter of 30 cm, each of the layers comprising sixty fluidic units (30), each of the units (30) comprising sixteen networks organized according to a radial symmetry around of a conduit (2) for distributing fluid to be filtered capable of circulating with a flow rate of 100 mVs for a pressure of 10 bars.

18. Filtration system (300) comprising: - at least one filtration device (1) according to one of claims 1 to 15; - a fluid temperature measurement system (47); - a fluid pH measurement system (56); - a geolocation system (48); - a leak or obstruction location system configured to generate an alarm signal in the event of a leak; - a pressure regulator (57); - a flow regulator (55); - an optical system configured to characterize the particles (50); - an ultrasonic radiation system (49, 51) for determining the nature of the polymer of the particles; - a servo system (52) for stopping the filtration device; - a pre-filtration system of the membrane filter or centrifugal filter type (42); - a system for treating the particles by enzymatic, chemical or physical method (43); - a wireless data transmission system.

19. Filtration method adapted to filter a fluid of at least one particle by implementing the device according to one of claims 1 to 15, comprising: - passing the fluid through said at least one filtration network with a flow rate of the fluid to be filtered of between 0.01 m3 / s and 100 m3 / s; - ensuring a pressure difference between the main inlet and the outlets of the device so as to drive said flow rate in said filtration device, the pressure difference being less than 10 bar; - said flow rate being such that the Péclet number of the particle in the flow of the fluid traveling the length of said particle concentration channel in the direction of flow is between 1.102 and 1.1020.

20. Method according to claim 19, further comprising a washing step (202) in which a washing fluid is passed through the channels forming the microfluidic network after the filtration step (201). 27

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