FR3136993A1 - SEPARATION ELEMENT AND ASSEMBLY OF AT LEAST TWO SUCH ELEMENTS - Google Patents

Abstract

TITLE OF THE INVENTION: SEPARATION ELEMENT AND ASSEMBLY OF AT LEAST TWO SUCH ELEMENTS An element (52) for separating a fluid medium to be treated into a retentate and a filtrate, comprising: - a fluid inlet to be treated, - a retentate outlet, - a filtrate outlet, the separation element (52) further comprising: - a network of at least one channel (63) comprising a porous wall covered with a separating layer configured to treat the fluid medium, the network being connected to the filtrate outlet, - a peripheral wall (62) between the inlet of fluid to be treated and the retentate outlet, the peripheral wall delimiting a filtration cavity comprising the network, the filtration cavity being separated into at least two fluid medium circulation circuits by the network. The abstract figure: Figure 10.

Description

SEPARATION ELEMENT AND ASSEMBLY OF AT LEAST TWO SUCH ELEMENTS Technical field of the invention

The present invention relates to a separation element and an assembly of two such elements. It applies, in particular, to the field of liquid medium filtration membranes.

State of the art

Separation processes using membranes are used in many sectors, notably in the environment for the production of drinking water and the treatment of industrial effluents, in the chemical, petrochemical, pharmaceutical, agri-food industries and in the field of biotechnology.

A membrane constitutes a selective barrier and allows, under the action of a transfer force, the passage or stopping of certain components of the medium to be treated. The passage or stopping of the components results from their size in relation to the size of the pores of the membrane which then behaves like a filter. Depending on the size of the pores, these techniques are called microfiltration, ultrafiltration or nanofiltration.

There are membranes with different structures and textures. Membranes are, in general, made up of a porous support which ensures the mechanical resistance of the membrane and also gives the shape and therefore determines the filtering surface of the membrane. On this support, one or more layers a few microns thick ensuring separation and called separator layers, filtration layers, separation layers, or active layers, are deposited. During separation, the transfer of the filtered fluid takes place through the separator layer, then this fluid spreads in the porous texture of the support to move towards the exterior surface of the porous support. This part of the fluid to be treated having passed through the separation layer and the porous support is called permeate or filtrate and is recovered by a collection chamber surrounding the membrane. The other part is called retentate and is, most often, reinjected into the fluid to be treated upstream of the membrane, using a circulation loop.

Conventionally, the support is first manufactured according to the desired shape by extrusion, then sintered at a temperature and for a time sufficient to ensure the required solidity, while retaining in the ceramic obtained the desired open and interconnected porous texture. This process requires obtaining one or more rectilinear channels inside which the separating layer(s) are then deposited and sintered. The supports are traditionally tubular in shape and comprise one or more rectilinear channels arranged parallel to the central axis of the support.

The interior volume of the support being defined and limited by its exterior dimensions and the area of the filtering surface being proportional to the number of channels, it was found that the area of the filtering surfaces of the filtration membranes manufactured from supports having such geometries come up against a ceiling and therefore have limited performance in terms of flow.

The principle of any tangential separation using filtration elements lies in a selective transfer whose efficiency depends on the selectivity of the membrane (the active layer) and the permeability (flow) of the filtration element considered in its entirety (porous support and active layer).

The performance of a filtration element is, in addition to the efficiency of the selective transfer previously described, directly proportional to the area of the filtering surface involved. Furthermore, the performance of a filter also results from its propensity to be easily cleaned in order to maintain a high permeation flux over time.

The S/V ratio in which S is the area of the exchange surface of the membrane and V is the volume of the separation element makes it possible to characterize the compactness of a membrane.

Historically and chronologically, single-channel cylindrical tubular separation elements appeared on the market, then parallel multi-channel tubular separation elements.

The first parallel multichannel separation elements, one of the advantages of which, in addition to increasing the total area of the filtering surface, lies in obtaining channels of small hydraulic diameters without risk of fragility for the separation element , comprised exclusively channels of straight circular sections.

The next generation abandoned the circular channels in order to better occupy the internal volume of the tube, increase compactness and increase the possibilities of turbulence.

It is noted thanks to these two examples that, with equal hydraulic diameter and for separation elements identical in shape and external dimensions, the transition from channels with a circular section to channels with a non-circular section makes it possible to increase the value of compactness.

Channels with a non-circular section have the disadvantage of having different radii of curvature within the same channel. Thus, when the membrane is deposited inside its channels, differences in the thickness of this membrane appear: it is particularly thicker in the more concave curvatures. This difference in thickness generates a preferential permeation flow towards the thinnest zones, thus creating a filtration imbalance. These extra thicknesses also create differential shrinkage when the ceramic is fired, which can cause cracks or separation of the membrane from its support.

It is commonly accepted by those skilled in the art that the wall thicknesses between the channels are limited towards low thicknesses by the extrusion process itself due to physical parameters such as mainly the dimensions of the particles of materials distributed in the extruded dough and the level of plasticity of this dough with regard to the pressure necessary for the dough to pass through the die.

The dimensioning of the channels inside a separation element obtained by extrusion is therefore limited, in addition to considerations of mechanical resistance and filtrate flow in the very porosity of the porous support, by the friction forces which, between the paste ceramic and the die, generate a risk of tearing and/or cracking.

The membranes known to those skilled in the art all present cleaning difficulties. Indeed, cleaning a membrane is generally carried out by injecting a cleaning solution at high pressure through a filtrate outlet, this process is called “counter-current cleaning”. However, cleaning in the center of the membrane is less effective than at its periphery since the cleaning solution arrives in a longer time at the center of the membrane, through the pores of the membrane, with less pressure.

The main problem with membranes known to those skilled in the art concerns their cleaning. One of the techniques generally used to clean them is called backwashing. It is carried out by returning permeate to the membrane by counter-current in order to remove the impurities fixed on its wall. However, cleaning the channels in the center of the filter media is less effective than the channels at its periphery since the permeate must pass through more porous support before arriving on the membrane. This higher pressure loss therefore generates a lower unclogging pressure for the channels at the heart of the filter media, that is to say those furthest from the permeate outlet.

Presentation of the invention

The present invention aims to remedy all or part of these drawbacks. In particular, the present invention makes it possible to create a filtrate evacuation network through channels, the channels forming different circulation networks of the fluid medium to be treated.

To this end, according to a first aspect, the present invention aims at an element for separating a fluid medium to be treated into a retentate and a filtrate, comprising:
- a fluid inlet to be treated,
- a retentate outlet,
- a filtrate outlet,
the separation element comprising:
- a network of at least one channel comprising a porous wall covered with a separating layer configured to treat the fluid medium, the network being connected to the filtrate outlet,
- a peripheral wall between the fluid inlet to be treated and the retentate outlet, the peripheral wall delimiting a filtration cavity comprising the network, the filtration cavity being separated into at least two fluid medium circulation circuits by the network.

Thanks to these arrangements, the surface represented by the peripheral wall of each channel is taken into account for the compactness calculation.

The present invention makes it possible to create a filtrate recovery network whose channels are positioned in the filtration cavity to recover the filtrate at the heart of the filter element. Such a filtrate network also makes it easier to clean the membrane by backwashing.

In addition, the network of filtrate channels forms a three-dimensional structure which creates different circuits that the flows of liquid medium to be treated can follow.

In embodiments, the network includes at least two channels and at least one intersection of a channel with another channel.

Thanks to these arrangements, the filtrate is quickly conveyed to the outlet. Conversely, when cleaning, the cleaning solution reaches the core of the membrane more quickly. Finally, the exchange surface of the separation element is increased.

In embodiments, at least one channel is helical.

Thanks to these provisions, when firing the porous wall, generally ceramic, the shrinkage does not affect the shape of the channel. In addition, the porous wall of the channel generates a turbulent flow in the filtration cavity, therefore limiting its clogging and causing a better exchange between the fluid medium to be treated and the porous wall.

In embodiments, the channel array has a three-dimensional structure that is generally gyroidal in shape.

Thanks to these arrangements, the three-dimensional structure of generally gyroidal shape makes it possible to generate turbulent flows in the fluid medium to be treated. Thus, locally, the turbulence on the surface of the membrane is increased, which facilitates the self-cleaning of the channel network. In addition, the flow generated is oriented thanks to the helices of the gyroid structure, the pressure loss in the separation element is therefore limited.

Such a structure also allows, at the inlet for the fluid medium to be treated, to present a convex surface which facilitates the flow of the fluid and does not create any retention zone.

Given the shape of the structure, the thickness of the porous wall of the channels is constant, therefore the pore volume is constant. In addition, the channel surfaces have the same constant average curvature at all points. The combination of these two characteristics makes it possible to obtain a regular deposit thickness of the separator layer without creating any surplus in the concave zones. The constant thickness of the porous wall limits the hydraulic resistance to the fluid medium. The thickness of the porous wall to be crossed being similar at all points, the pressure loss generated when the fluid passes through the porous wall is similar at all points.

Furthermore, when the network is made of ceramic, the three-dimensional structure of generally gyroidal shape makes it possible to avoid cracks during the firing of the ceramic. In fact, the three-dimensional propellers react like a spring, absorbing shrinkage during firing in all three dimensions and removing stress concentrations on each axis.

Finally, such a network can be obtained by three-dimensional printing, which facilitates the manufacture of the separation element.

In embodiments, the porous support is ceramic.

These embodiments make it possible to obtain an inorganic porous support whose porosity can be adapted.

In embodiments, the network of channels opens through the peripheral wall, with the filtrate outlet around the peripheral wall.

Thanks to these arrangements, the filtrate is extracted around the membrane.

In embodiments, the separation element which is the subject of the present invention comprises a central pipe, into which the network of channels opens, the filtrate outlet being connected to the central pipe.

Thanks to these arrangements, it is possible to extract the filtrate coaxially with the flow of fluid medium to be treated.

In embodiments, each channel has a circular section.

Thanks to these arrangements, the routing of the filtrate to the filtrate outlet is facilitated and the pressure losses are reduced.

In embodiments, the peripheral wall has a shoulder at the fluid inlet to be filtered and a corresponding shape at the retentate outlet, the shoulder being configured to be assembled with the corresponding shape of another element.

Thanks to these arrangements, two elements are easily nested. The separation length can therefore be defined according to the operator's needs. In addition, if an element is damaged or defective, it is easy to replace it.

According to a second aspect, the present invention aims at an assembly of at least two elements which are the subject of the present invention, by interlocking the shoulder of one element around the corresponding shape of the other element.

The aims, advantages and particular characteristics of the assembly which is the subject of the present invention being similar to those of the element which is the subject of the present invention, they are not recalled here.

Brief description of the figures

Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the separation element and the assembly which are objects of the present invention, with regard to the appended drawings, in which:

represents, schematically and in section, a first particular embodiment of the separation element which is the subject of the present invention,

represents, schematically and in section, along an axis perpendicular to the section represented in , the first particular embodiment of the separation element which is the subject of the present invention,

represents, schematically and in perspective, three embodiments of three-dimensional surfaces of generally gyroidal shape obtained according to different parameters,

represents, schematically and in perspective, a first embodiment of an elementary block of a network of channels of gyroid structure,

represents, schematically and in perspective, a first embodiment of a network of channels of three-dimensional structure of generally gyroidal shape by reproduction of the elementary block represented in ,

represents, schematically, two three-dimensional surfaces of generally gyroidal shape and three sections of each of the surfaces according to corresponding positions and parallel axes,

represents, schematically and in perspective, a second embodiment of a network of channels of three-dimensional structure of generally gyroidal shape,

represents, schematically and in plan, a first embodiment of an assembly which is the subject of the present invention,

represents, schematically and in section, a third particular embodiment of the separation element which is the subject of the present invention and

represents, schematically and in perspective, a separation element which is the subject of the present invention.

The present description is given on a non-limiting basis, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

Remember that a network is a set made up of lines or elements that communicate or intersect. In other words, a network is an intertwining of objects, more or less regular.

Remember that a channel is a flow conduit with a hollow and elongated shape, allowing the passage of liquids or gases from one place to another. A channel network is therefore a set of channels that communicate or intersect.

Finally, we recall that a circulation circuit of a fluid medium is a path followed by a flow of said fluid medium. In other words, it is a path that a particle in the fluid medium can follow.

We recall that:
- structure represents a way in which the parts of a whole are arranged together, a three-dimensional structure of generally gyroidal shape is therefore a structure of three-dimensional elementary blocks of generally gyroidal shape,
- a surface is represented by two dimensions and a full volume is a volume composed of matter, conversely a volume is empty. For example, the space delimited by a channel is an empty volume and a wall is a full volume.

We call :
- “top” which is at the top of figures 1 to 10,
- “bottom” which is at the bottom of figures 1 to 10,
- “left” what is to the left of figures 1 to 10,
- “right” which is to the right of figures 1 to 10,
- “lateral” or “side”, which can be on the left or on the right.

We now note that figures 1, 2, 8 and 9 are not to scale. Figures 3 to 7 and 10 are to scale, but at different scales.

We observe, in Figures 1 and 2, which are not to scale, two schematic sections of a first embodiment of the element 100 which is the subject of the present invention.

The element 100 is inserted into a conduit 25 for conveying the fluid medium to be treated. Such conduits 25 are known to those skilled in the art. The conduit 25 has, on its periphery, a filtrate outlet 15. The flow of fluid medium to be treated is represented by an arrow 12, which enters the separation element 100 via an inlet 11 on the left in . The outlet 13 of retentate 14 is shown on the right in .

The separation element 100 has the shape of a truncated cylinder with a circular base of diameter less than the diameter of the conveying pipe 25. The free space between the conveying pipe 25 and the separation element 100 is configured to convey the filtrate 16 to the filtrate outlet 15. The filtrate can therefore circulate around a peripheral wall of the separation element 100 and reach the filtrate outlet 15. In other words, the network of channels opens through of the peripheral wall 20, the filtrate outlet 15 being around the peripheral wall 20.

The separation element comprises a network of a channel 17. The channel 17 comprises a porous wall 18 covered with a separator layer 19 configured to treat the fluid medium. The porous wall 18 of each channel 17 is preferably made of ceramic.

In embodiments, the channel array is made by three-dimensional printing. For example, the channel array can be made using a powder bed printer configured to bond the ceramic powder. According to another example, the preparation of a ceramic suspension is carried out by mixing a photosensitive resin, a dispersant and ceramic powder. Then, the whole is subjected to the action of light of a specific wavelength polymerizing the points of the layer to be hardened to form a skeleton on which the separating layer is deposited.

The separating layer 19 is perhaps made of any material known to those skilled in the art and selected according to the elements to be filtered. For example, the separating layer can be made of metal oxide such as alumina, zirconia, titanium, silicon carbide. The cut-off threshold of the separating layer is selected according to the application for which the membrane is intended. In microfiltration, the separating layer typically has pores with a diameter of between 0.1µm and 10µm. In ultrafiltration, the pore diameter is between 5nm and 100nm.

The channel 17 opens through the peripheral wall 20 and is connected to the filtrate outlet 15. The peripheral wall 20 can be composed of the same materials as the materials composing each channel 17. In this way, the peripheral wall 20 also makes it possible to treat the fluid medium to be treated. In other preferred embodiments, the peripheral wall 20 is made of impermeable material, such as resin or stainless metal.

The peripheral wall 20 delimits a filtration cavity 22, in other words, it is the space circumscribed by the peripheral wall 20. The channel 17 is contained in the filtration cavity 22. The channel 17 separates the cavity filtration 22 in at least two circulation circuits 23 and 24 of fluid medium. We observe these two circulation circuits, 23 and 24, in , one of the circuits passing to the left of channel 17, the other passing to the right of channel 17.

Figures 1 and 2 represent a simplified embodiment of the invention. More generally, when the network of channels includes more than one channel, the network of channels 17 forms a mesh of circulation circuits of the fluid medium. In other words, the interweaving of the channels attached to the peripheral wall necessarily forms several possibilities for the passage of the flow of fluid to be treated.

In other words, the network of channels also forms a circulation network for the fluid medium to be treated, between the channels.

In the embodiment shown in Figures 1 and 2, the network of channels 17 opens through the peripheral wall.

We observe, on the , another embodiment of a separation element 26 which is the subject of the present invention. The embodiment shown in is identical to the embodiment shown in , with the exception that the network of channels 27 is composed of helical channels forming intersections at each helix pitch. The filtrate can therefore circulate from one helix to the other. The axis of the helices of the channels is coaxial with the axis of the peripheral wall 20.

Schematically, three helices have been represented, however, it is obvious that the number of helices depends on the dimensions of the separation element, the dimensions of the channels and the porous wall as well as the chosen helix pitch. The lower the pitch, the larger the filtering surface and therefore, the greater the compactness of the membrane.

Preferably, the channels of the embodiments described above and below have an elliptical or circular section. For example, the channels can have an interior diameter of between 0.2mm and 5mm and an exterior diameter of between 0.5mm and 8mm. We call “interior” the surface of the channel configured to evacuate the filtrate and “exterior” the surface of the channel in contact with the fluid to be treated. In other words, for a channel section, the interior diameter is the smallest diameter between two points on the wall and the exterior diameter is the largest diameter between two points on the wall.

Preferably, the porous support described above and below has between 1 and 20 pores per cubic centimeter and a porosity of between 50% and 90%.

The different embodiments of networks represented in Figures 1 and 2, 3 to 6 and 8 have different geometries, but are composed and manufactured in the same way as described with regard to the .

We observe, in , an embodiment of a network of channels 30 having a three-dimensional structure of generally gyroidal shape.

The three-dimensional structure of generally gyroidal shape is a triply periodic surface geometry.

Periodic surfaces are “rigid” objects: a portion of the surface, however small, determines the entire surface (for example, the only periodic surface containing a planar part is the entire plane). Thus, we cannot deform a periodic surface at a given location without deforming it globally. A periodic surface is said to be triply periodic when it is made up of an elementary block which repeats in three spatial directions, that is to say three orthogonal directions.

A very close approximation to the representation of a three-dimensional surface of generally gyroidal shape can be given by the following function:

[Formula 1]

F(x, y, z) = t,

in which

[Formula 2]

“a” is the periodicity of the gyroid and “t” is a real number.

We observe in , three different representations of three-dimensional surfaces of generally gyroidal shape presenting different values for a and t:
- the three-dimensional surface of generally gyroidal shape 300 has a value for a of 2π and t equal to zero,
- the three-dimensional surface of generally gyroidal shape 301 has a value for a of 2π and t equal to 1.3,
- the three-dimensional surface of generally gyroidal shape 302 has a value for a of 2π and t equal to 1.05.

All three-dimensional periodic surfaces with a gyroidal pattern belong to the cubic space group I4132 and are defined by formula 1 above in which:

[Formula 3]

−1.5 < t < 1.5

It is in particular these surfaces which are represented by the three-dimensional surfaces of generally gyroidal shape, 301 and/or 302.

The cubic space group I4 ₁ 32 is known to those skilled in the art.

We can therefore define a three-dimensional elementary block of generally gyroidal shape, that is to say a full volume between two three-dimensional surfaces of generally gyroidal shape according to formula 4 below:

[Formula 4]

t<F(x, y, z)<t’

In which the absolute values of t and t' are strictly less than 1.41, and such that t and t' have the same sign and the absolute value of t is strictly less than the absolute value of t'. The figure represents the explanation of the choice of the absolute value limit value of t and t’.

The network 31 then obtained consists of continuous channels whose interior surface 301 is given by the function F(x, y, z) = t and the exterior surface 302 is given by the function F(x, y, z) = t '. In the network 31, the surface 301 defines channels and the surface 302 defines a surface in contact with the fluid to be treated.

An elementary block 30 of the network 31 is represented in . By repeating the elementary block 30 in the three spatial directions used to generate the elementary block, a network 31 of interconnected channels is obtained.

The elementary block 30 of network 31 represented in can be reproduced periodically over the volume of the filtration cavity. Furthermore, the fluid medium can follow as many filtration circuits as there are connections between the empty spaces left by the exterior gyroid shape 302.

Network 31 represented in , comprises eight elementary blocks 30 arranged in such a way that two elementary blocks 30 are aligned in each of the three spatial directions used to generate the elementary block.

The elementary block 30 constitutes a porous wall. In other words, the full volume between the three-dimensional structures of generally gyroidal shape, 301 and/or 302 of the elementary block 30, forms the porous wall.

There represents two embodiments of gyroid surfaces, 400 and/or 500. The gyroid surface 400 has a value for a of 2π and t equal to 1.30 and the gyroid surface 500 has a value for a of 2π and t equal to 1.4.

We observe, in , that the three-dimensional structure of generally gyroidal shape has a connectivity of three struts per node. The cross section of each spacer of the three-dimensional structure of generally gyroidal shape changes from an elliptical shape close to a node to a circular shape halfway, that is to say in section BB, between two nodes. The elliptical shapes are shown in sections AA and CC of the gyroids, 400 and/or 500. The main directions of the elliptical cross section switch discontinuously at the midpoint.

For absolute values of t greater than 1.41, most of the material is present at the node boundaries. The absolute value of t equal to 1.41 represents a limiting case, because the area of the circular section halfway, that is to say in section BB, is zero.

For this reason, the absolute value of t is strictly less than 1.41, otherwise the channels would not allow passage of the filtrate.

We observe, on the , a network 40 of three-dimensional structure of generally gyroidal shape 30 provided with a central pipe 41, into which at least one channel 42 opens at the level of an opening in said central pipe 41. Similar to the , the channel has a porous wall.

We observe three channels following helices, 43, 44 and/or 45 with perpendicular axes corresponding to the axes of the mark 46 represented in Figures 4 to 6. The mark 46 corresponds to the axes used to generate an elementary block 30. Preferably, the three channels following the helices 43, 44 and/or 45 have the same pitch and the same diameter.

For example, in the embodiment shown in , the central pipe 41 has an internal diameter of between 5mm and 50mm and the propellers have a radius of between 1mm and 10mm, their pitch is between 2mm and 20 mm.

The network 40 is configured to be surrounded by a waterproof peripheral wall, for example made of resin and the filtrate outlet is configured to be connected to the central pipe 41. Preferably, the central pipe 41 is in the form of a cylinder trunk with a circular base. The central pipe 41 is coaxial with the peripheral wall 20, and with the conveying conduit 25 in which the separation element provided with the network 40 is placed.

We observe, in , an assembly 50 of several separation elements 52 object of the present invention.

The assembly 50 is positioned in a conveying pipe 54 comprising, in the upper part, an inlet of fluid medium to be treated, in the lower part, a retentate outlet 56, on the periphery on the right, a filtrate outlet 57.

The separation elements 52 can present any network previously described, the network embodiment 30 represented in was represented in . The separation elements 52 comprise, in the upper part, a shoulder in the form of a cylinder trunk whose axis is coaxial with the axis of the conveying pipe 54 when the element is positioned in the pipe. Preferably, the shoulder has an external diameter, that is to say in contact with the conveying pipe 54 when the element 52 is positioned, corresponds to the diameter of the conveying conduit 54. The shoulder has a diameter interior, that is to say facing the filtration cavity, substantially equal to the diameter of the peripheral wall of element 52.

In embodiments, the shoulder 51 can be provided with a key and the corresponding shape at the bottom of the element 52 is provided with a corresponding shape 53. In this way, the networks, especially when they have a three-dimensional structure of generally gyroidal shape, are aligned. In other words, the helices in the axis of the conveying pipe 54 are aligned from one element 52 to the other.

Preferably, the shoulder is made of resin and the corresponding shape 53 of the other element as well. In this way, when assembling two elements, a polymerization step is implemented to fix the two elements together in a watertight manner. In other embodiments, sealing is ensured by the presence of an O-ring between the two elements 52.

In the embodiment shown in , the filtrate outlet is positioned on the delivery pipe, around the peripheral wall. Of course, if the network is equipped with a central pipe, the filtrate outlet is connected to the central pipe.

There represents another embodiment of a separation element 52. The separation element 52 comprises a network 31 of channels composed of elementary blocks 30. The separation element 52 comprises a peripheral wall 62. The channels of the network 31 open through the peripheral wall 62 and is connected to a filtrate outlet. The peripheral wall 62 can be composed of the same materials as the materials making up each channel. In this way, the peripheral wall 20 also makes it possible to treat the fluid medium to be treated. In other preferred embodiments, the peripheral wall 62 is made of impermeable material, such as resin or stainless metal.

Preferably, the peripheral wall 62 is in the form of a truncated cylinder with a circular base.

The filtration element comprises assembly surfaces 61 in continuity with the peripheral wall 62. The section of the separation element comprising the assembly walls 61 does not include a network 31 of channels. In other words, only the volume defined by the peripheral wall 62 includes the network 30 of channels. In variants, the entire space delimited by the assembly walls 61 and the peripheral wall 62 includes the network 31.

Preferably, the assembly walls 61 are in the form of a cylinder trunk with a circular base, with an axis coinciding with the axis of the cylinder trunk defining the peripheral wall 62 and having a through hole of circular section of the same diameter as the diameter defining the peripheral wall 62.

In embodiments, the separation element 52 comprises an assembly wall 61 on either side of the separation wall 62. These embodiments make it possible to center the network of channels 31. In variants (not shown), the separation element 52 only has one assembly wall 61.

In variants (not shown), a separation wall 61 has a shoulder and another separation wall 61 has a corresponding shape as described with reference to the .

When the user wishes to clean the separation element 52, water is injected through the filtrate outlet. Additionally, a pneumatic pump can be connected to the filtrate outlet to inject water in spurts through the membrane, using the filtrate outlet. In embodiments, it is also possible to perform cleaning by vibration in ultrasonic or infrasonic frequencies.

Claims (10)

Element (100, 26, 52) for separating a fluid medium to be treated (12) into a retentate (14) and a filtrate (16), comprising:
- an inlet (11, 55) for fluid to be treated,
- a retentate outlet (13, 56),
- a filtrate outlet (15, 57),
the separation element being characterized in that it comprises:
- a network (27, 31, 40) of at least one channel (17, 27, 301, 41) comprising a porous wall (18, 302, 42) covered with a separating layer (19) configured to treat the medium fluid, the network being connected to the filtrate outlet,
- a peripheral wall (20, 62) between the fluid inlet to be treated and the retentate outlet, the peripheral wall delimiting a filtration cavity (22) comprising the network, the filtration cavity being separated into at least two circuits ( 23, 24) of circulation of fluid medium through the network. Element (26, 52) according to claim 1, wherein the network (27, 31, 40) comprises at least two channels (27, 301, 42) and at least one intersection of a channel with another channel. Element (26, 52) according to claim 2, in which at least one channel (27, 301) is helical. Element (52) according to claim 3, in which the network (31, 40) of channels (301) has a three-dimensional structure of generally gyroidal shape. Element (100, 26, 52) according to one of claims 1 to 4, in which the porous support (18, 302) is made of ceramic. Element (100, 26, 52) according to one of claims 1 to 5, in which the network of channels opens through the peripheral wall (20, 62), the filtrate outlet (15, 57) being around the peripheral wall. Element according to one of claims 1 to 5, which comprises a central pipe (41), into which the network (40) of channels (42) opens, the filtrate outlet being connected to the central pipe. Element (100, 26, 52) according to one of claims 1 to 7, in which each channel (17, 301, 42) has an elliptical or circular section. Element (52) according to one of claims 1 to 8, in which the peripheral wall (20) comprises a shoulder (51, 61) at the inlet (55) of fluid to be filtered and a corresponding shape (53, 61) at the retentate outlet (56), the shoulder being configured to be assembled to the corresponding shape of another element. Assembly (50) of at least two elements (52) according to claim 9, by interlocking the shoulder (51, 61) of one element around the corresponding shape (53,61) of the other element.