WO2025046183A1 - Filter unit with encased glass fragments and arrangement of such units in a pool water filtration system - Google Patents

Abstract

In a pool filtration system, one or more filter units (4, 104) allow water to be treated effectively in contact with angular glass fragments (M2, M3), while at the same time making water-permeable bags (5) that constitute the casing of the units easier to handle by gripping. The filtration chamber of the system can house the units, inside which the filtration members form a bulk mass through which the pool water can pass and which includes the glass fragments (M2, M3) of angular geometry, a maximum dimension of the glass fragments being less than or equal to 4 mm, preferably less than or equal to 2 mm. A filtering arrangement, for lining said chamber, includes a tiered arrangement of the flexible filter units (4, 104), possibly in the form of annular layers of units when a central pipe (T) discharging the clean water is provided.

Description

Filter unit with wrapped glass fragments and arrangement of such units in a pond water filtration system

Technical field

[0001]The invention relates to the field of water purification. The present disclosure relates more particularly to a filter unit and a filter arrangement usable in a pond filtration system, as well as a method of obtaining a filter unit.

Prior art

[0002] It is known to carry out filtration of water from a basin such as a swimming pool or water tank. For the purposes of the present disclosure, the term swimming pool is broad. It also includes any type of swimming pool or set of water basins, in particular this includes the case of an installation for a whirlpool or jacuzzi, spa or the like. Such a water tank may correspond for example to a fountain or an ornamental basin.

[0003] Basins such as swimming pools are generally designed with water circulation systems. For circulation, the water is sucked up by one or more pumping devices via a surface suction device known per se, namely a skimmer part, and fed to a more or less efficient filter, in particular which may include a sieve and/or a filter mass, this filter being installed near the pumping device(s). Such a filtration device is intended to filter large particles of dirt, such as leaves and insects, down to fine particles, such as pollen and scales, from the circulating water. After passing through the filter, the water is generally reintroduced into the swimming pool or equivalent basin via an inlet arranged below the surface of the pool water.

[0004] The filter generally has a box or housing delimiting a filtration chamber, into which a bulk material can be poured. Most often, the bulk material is sand that the user can obtain in packaged form. Over time, the particles present in suspension in the water, which are filtered by the filtration device, are deposited on the filtration surface in the chamber. In practice, filtration materials with sand lose their effectiveness, which requires the sand already used to be thrown away and:

- either buy new quantities of sand,

- either store a large stock of sand which represents a significant amount of space.

[0005] More generally, the filtration of large quantities of pond water which is not protected against external contamination/deposits of leaves or other, with a volume of water representing several thousand or tens of thousands of liters in most cases, frequently causes fouling or clogging of the filtration material (increase in the pressure inside the filter). In the case of sand or bulk materials, either large quantities of water must be consumed to counterbalance the clogging (backwashing), or the user must remove the filling material from the filtration chamber, in a tedious manner. Most often, it is generally not permitted to reuse this clogged bulk when it is extracted from the filtration chamber. Indeed, cleaning with water after extraction is not easy and the instructions for use clearly indicate the need to change the sand.

[0006] Cartridge filters are also known, the notorious disadvantage of which is that they require frequent purchase of new cartridges, at intervals generally specified by the manufacturer or even at a higher rate due to incidents. The maintenance cost ultimately proves to be more expensive. It should also be noted that such single-use cartridges have a negative ecological impact, which are thrown away and thus become non-recyclable waste.

[0007] There is thus a need to minimize the effort required for the maintenance of a filter for a water basin, while maintaining a high level of efficiency in the treatment of the water in this basin (high hygienic performance/prevention of the appearance of discoloration in the water). The filtration parts would benefit from being robust, compatible with a satisfactory level of filtration and simple to handle during maintenance.

Summary

[0008] In order to improve the situation (to facilitate maintenance related to the filter of a pond), a filter unit is proposed, capable of occupying a filtration chamber, for example by being combined/associated with other filter units to form a filtration layer. More particularly, the filter unit is capable of filling all or part of a filtration chamber of a water filtration system for a pond, the filter unit comprising:

- a bag (closed bag) which has a wall, permeable to water, making it possible to delimit an interior volume;

- filtration members forming a bulk mass capable of being passed through by the water of the basin; these filtration members which are maintained in the interior volume comprising or consisting of glass fragments, the glass fragments each having an angular geometry, a maximum dimension of the glass fragments being less than or equal to 4 mm, preferably less than or equal to 2 mm.

[0009] With such a filter unit, much easier manipulations are permitted for inserting and removing the bulk of glass fragments from the filtration chamber (the closed bag allows the filter unit to be mounted in the filtration chamber, and respectively to be removed, as a single unit). In addition, a distributed filtration effect is obtained both on the envelope constituting the bag and on the glass fragments whose irregular surface makes it possible to increase the surface/volume ratio of the filtration members. [0010] Thanks to the use of glass fragments, the ecological impact is greatly reduced. Such fragments, which can be derived from recycling, are compatible with reuse of the filter units via simplified extraction and low-water-consuming washing.

It is possible to minimise the consumption of silica sand, which is a resource in sharp decline, on the one hand, and to reduce the quantities of water required for cleaning bulk filtration components.

[0011] The filter unit is compatible with low-carbon production, for example by reusing glass (recycled glass, for example from sorting among fragments resulting from the implosion of a discarded container). An interesting quality of the glass fragments, regardless of whether they are recycled or not, is their self-sterile property, which limits fouling inside each filter unit. The oxides contained in the glass act directly on the catalytic properties of the filtration system. Unlike other filtering members, the bulk of angular glass fragments can achieve fine filtration while allowing short and water-saving backwashes.

[0012] The bag may consist of a rot-proof textile, optionally the thread elements of which consist of or are based on a resistant polymer (for example a semi-crystalline polymer, for example PET or rPET). The thread(s) of the bag are mechanically robust and made of a chemically resistant plastic material, not degrading over time under the action of chemical agents introduced into the water to treat it (such as chlorine, salt, possible flocculants, etc.). A net structure with meshes below approximately 0.4 mm may be preferred in order to prevent any risk of glass fragments escaping.

[0013] Advantageously, a sand filtration system may be compatible with such filter units, which in practice allows the filter loads packaged in different bags to be distributed. Several grades may be used in different filter loads distributed in bags. The bags are optionally of similar size and/or with a deformation capacity (to facilitate the filling of the filtration chamber), being filled below their maximum capacity.

[0014] The particle size of the glass fragments in the bag can be selected with sufficient fineness for filtration quality, knowing that an assembly of several filter units can allow the filling of the filtration chamber, if necessary with a variation in the particle sizes, typically by interposing a filter layer or prefilter between the access inlet to the filter chamber and the filter unit(s) of a layer of filtration presenting grade I or grade corresponding to the finest granulometry (which does not exceed 1 mm for example).

[0015] In embodiments, the interior volume of the bag is delimited between two opposite faces (possibly two faces distributed in two respective textile pieces initially separated and sewn or connected together to delimit the interior volume) of the bag. The bulk mass may extend from one to the other of two ends of the bag, between the two opposite faces.

More generally, the bag can have any type of suitable format, with or without the formation of gusset(s) or predetermined folds, provided that the filter unit can vary in its shape and conform to the space available in the filtration chamber.

[0016] In embodiments of the filter unit one or more of the following features may be used:

- the bag is a textile bag, having a closed configuration which is adapted to allow the filter unit to be mounted as a single unit in the filtration chamber, and respectively to be removed as a single unit.

- the bag is sized to be elongated, between its two opposite ends, so as to have a length greater than the maximum thickness of the filtration unit.

- the internal volume can form a first reception space for the glass fragments, optionally supplemented by an additional internal volume delimited in the same filter unit, for example by the bag or an extension of the bag.

- two bag portions of a filter unit, each forming a pocket (inner volume) for receiving bulk with glass fragments, may optionally be connected to each other by a junction or link, for example a junction remote from/located opposite an end of the initially open bag portion through which the filling with glass fragments was carried out; this arrangement may make it possible to minimise handling by reducing the total number of filter units that can fill a filtration chamber whilst maintaining a relatively flattened conformation of the respective bag portions (which facilitates stacking of the filter units).

- at least 95% of the mass of the glass fragments is distributed in glass fragments having a particle size, measured by dry sieving, which is greater than or equal to 0.4 mm.

- the glass fragments may have a characteristic size ranging between two limits located in the interval from 0.5 to 3 mm, for example to allow a filtration fineness of less than 30 microns (possibly of the order of 15 microns) when the filter units are superimposed to fill more than half of a filtration chamber of a housing. [0017] The filter unit, with small loose glass fragments wrapped in a receiving part of the bag, thus forms a flexible/relatively flexible partition preventing the mixing of glass fragments packaged in different units, while allowing filter units to be attached to each other within an arrangement of such units, in the water filtration system (filtration chamber) for a pond. The filtration chamber may be delimited by a box or housing having a sand filter type format.

[0018] When strainers or water re-suction parts are provided in a lower part (lower compartment or sub-volume of the filtration chamber), provision may be made to distribute a layer of a bulk of filtration members whose particle size (strictly greater than 1 mm for example) is greater than that of the fragments contained in filtration units located higher in the filtration chamber. The bulk thus deposited may form a homogeneous layer in which the strainers are embedded/coated, and on which filter units may rest, for example filter units filled with glass fragments of a size not greater than 1 mm.

[0019] According to one option, the capacity of the bag (corresponding to the internal volume) can be between 0.75 and 2.5 liters, possibly more. It is understood that the filter unit is easily handled, for example grippable with one hand (including in an area substantially in the middle of the bag, between its two ends).

[0020] Whatever the precise design (particular geometry, capacity) of the bag, the latter has a closed configuration (definitive or locked) making it possible to ensure that the filtration members are maintained in at least one interior volume. The bag may have a mesh of submillimeter size and smaller, for example at least two times smaller, than the characteristic size of the smallest angular glass fragments contained in this bag. It is understood that a barrier effect is obtained to retain the smallest glass fragments contained in the filter unit.

Typically, a filter unit may include fragments with a characteristic size/diameter (equivalent diameter) of the order of 1 mm (+/- 0.6 mm). Where appropriate, a filter unit primarily includes submillimeter-sized glass fragments with a lower limit that falls below 0.7 mm. This can allow very fine filtration, preferably without falling below 0.4 mm.

[0021] In exemplary embodiments of the filter unit, the glass fragments represent at least 60% by weight, for example less than 75% by weight, more preferably at least 90 or 95%, of the bulk mass present in the interior volume. Filtering members of a size similar to the fragments or slightly larger, flexible or not, hollow/porous or not, resistant to the filtration treatment over time, may optionally be provided in certain cases, for example to create a filtration effect. ventilation or partitioning between the glass fragments.

Additionally or in complement:

- the glass constituting the fragments, non-porous, can have a density at least equal to 1.1 or 1.2 g/ ^cm3 .

- the glass fragments have sharp edges and angles; an angular geometry means, in all that follows, that the glass fragments have, as visible under a microscope for example, sharp edges and angles, typically less than 140° (far from the flat angle), for example less than or equal to 120°. They thus have a non-round geometric shape.

[0022] The bag may be designed to be generally flexible. The mesh of the bag is regular in a receiving portion of the bag for receiving the glass fragments, in order to maintain a submillimeter mesh size in each contact zone between the bag and the glass fragments forming the filtration members.

[0023] In embodiments of the filter unit, the following may optionally be used:

- the bag has a sewn structure which has: first wire elements which extend generally in a first direction, and which are preferably spaced from each other in a second direction distinct from the first direction; and second wire elements which engage with a plurality of the first wire elements to form a mesh.

- the filter bag is made of polyester or similar plastic, for example used in plastic bottles or containers that are recycled.

- the bag is sewn with thread(s) based on a polymer material, in particular a polyester, preferably PET or rPET (recycled).

- the bag is made by sewing PET thread(s), for example in PET at least partly recycled.

- the filling of the interior volume by the filtration organs is partial to allow the filter unit to be deformable with an ability to bend, preferably so that the bag can be curved, possibly with a radius of curvature of less than 30 cm.

- a textile material of the bag which delimits the interior volume (V5) has a weaved warp mesh structure.

- the textile material constituting the bag can define both the interior surface of the bag and the exterior surface.

- a textile material of the bag which makes it possible to delimit the interior volume is designed using threads which have a density (linear mass) ranging for example from 40 Deniers to 65 Deniers. - more particularly, the density for such wire elements (linear mass) can be between 45 and 60 Deniers.

[0024] In options, it is provided that:

- the bag has two longitudinal strips forming the two opposite ends of the bag, at which threads from a first face of the bag and threads from a second face of the bag are connected.

- the two longitudinal strips, including the wire/thread elements, are part of a periphery of the bag which completes/surrounds a receiving portion where the filtration organs are received.

- the bag has two margin strips corresponding to longitudinal sewing areas (longitudinal seams) and two opposite ends where transverse seams are formed.

- the longitudinal seams or strips and the ends with transverse seams are part of a periphery of the bag which surrounds a receiving part (useful part for delimiting the interior volume) of the filtration organs.

- at least one of the two ends of the bag, a first wall of the bag is connected, for example welded, to a second wall of the bag.

- it is intended to close four sides, or three sides when a fold is made to obtain a first side of the bag (three or four joining sides, in the non-limiting option of a substantially rectangular periphery) between the two walls of the bag, so as to prevent any risk of loss of a filtration member.

- to form the bag, we start with a sewn piece (in the format of a rectangular sheet) which we fold to overlap the edges and obtain a side delimited by/where a folding line of the piece is located.

- considering the folding line as a bottom side (bottom when the temporary opening is still present, before filling), we understand that the bag has two longitudinal edges which are typically sewn.

- a transverse seam is made, opposite a bottom part or folding line, after filling with filter organs in order to close the bag.

[0025] In embodiments limiting the complexity of the filter unit, the bag consists of a part, preferably made of a single plastic material. Whether the bag is a sewn part or assembled by joining different sewn parts, it is possible to use at least one of the following features:

- the filter bag is reusable with its contents.

- the filter bag has a permeability with a mesh size greater than 100 or 200 microns, while preferably being submillimeter.

- the maximum size of the glass fragments present in each bag is less than or equal to 3 or 4 mm, for example less than or equal to 1.8 mm. - the external surface area of each bag is less than 0.2 ^m2 .

- the bag has two portions linked together by a seam or equivalent fastening, the surface of each portion having a dimension of the order of 20*45 cm.

[0026] In some embodiments, a welding step (for example hot and/or using ultrasound) is carried out after filling the interior volume (by inserting the filtration members). In all cases, the bag is provided with a bonded, sealed or welded strip in order to close a filling opening through which the filtration members have been introduced into the bag, these filtration members having been sorted beforehand by sieving (where appropriate after a step of obtaining the glass fragments, by implosion for example using a rotor system to create impacts).

In options, the maximum difference in size between the smallest glass fragments and the smallest glass fragments contained in the same filter unit can be less than 0.7 or 0.8 mm.

[0027] The bag may be lightweight, without a wrapping overlayer. Thus, meshes of the bag may be delimited, in each of the opposite faces of the bag, on the one hand between the first adjacent wire elements two by two and, on the other hand, between the second wire elements.

In embodiment options independent or complementary to the above, the first filamentary elements are larger (in section) than the secondary filaments.

[0028] After filling the bag with the glass fragments/filtering members, via a (temporarily) open side, the bag can be closed by making a weld parallel to the first direction (direction of the first wire elements), or by making a seam.

[0029] According to one aspect, there is provided a filter arrangement usable in a water filtration system for a pond, and capable of purifying liquid water from the pond, this arrangement comprising several filter units as defined above, the arrangement including a staggered arrangement of the filter units in a filtration chamber of the water filtration system, which makes it possible to distribute contact surfaces formed by the glass fragments in the different filter units (within the chamber), knowing that a particle size, determined by dry sieving, of the glass fragments present in at least part of the bags of the filter units corresponds to an interval bounded by:

- a first submillimeter dimension forming a lower limit of the interval,

- and a second dimension, forming an upper limit of the interval, which does not exceed 1 or 2 mm.

[0030] With this arrangement, it is possible to obtain a modular arrangement, the conformation of which can change depending on the number of filter units arranged against each other. the others, for example with interface zones between the units which are distributed in three dimensions. In options, a stack of annular layers can be obtained, with in each annular layer at least two or three filter units. For at least one layer provided in such a stack, the lower particle size limit can be of the order of 0.4 mm. Optionally for another layer of filter units, for example arranged closer to an inlet of the filtration chamber, another lower particle size limit can be provided for the glass fragments, for example of the order of 1 mm.

[0031] According to a particular feature, one or more of the filter units define an intermediate filtration layer in which the glass fragments, preferably provided with the finest grade in the arrangement, allow a greater filtration finesse, compared to/with:

- a pre-filter layer formed by at least one other filter unit located closer to an access inlet of the chamber for the introduction of the liquid water to be purified; and

- a bulk of glass fragments poured without wrapping into an outlet region, which is preferably at the bottom of the filtration chamber and/or in a region located lower than the intermediate layer in the chamber.

[0032] The filtering arrangement makes it possible to greatly facilitate the maintenance of the filtration system, with, in addition, compatibility with a type of stacking of units which can very significantly delay the clogging phenomenon, for example to the extent that the finest grade can be offset in the filtration chamber, after a prefilter or a prefilter layer (for example on the side of the most upstream zone in the filter chamber) composed of filter units of a less fine grade.

[0033] Several superimposed filter units can be assembled, while ensuring a high level of fine filtration, if necessary with a distribution taking into account the different grades provided in the filter units; a marker, a color and/or a distinction in the shape or geometry of the bags can make it possible to visualize the differences between the filter units, in order to be able to obtain a good compromise between filtration fineness, ease of maintenance and spacing of maintenance (much less clogging).

[0034] In options, a substantially staggered arrangement of the filter units may be set up in the filtration chamber, including for the pre-filter layer where appropriate. More generally, a suitable stacking of the filter units containing differentiated particle sizes of the glass fragments (typically from recycling) may be established without the risk of glass fragments mixing through the layers of filter units, taking into account the mesh of the nets or bags (which may also be made of recycled material) constituting the external envelope of these filter units.

During use/treatment, the filter bed is mobilized on a very specific surface significant and in depth, avoiding generating a significant pressure loss over the course of filtration cycles.

[0035] The filter arrangement may include layers of filter units, the lowest of which may be superimposed directly on a bulk of glass fragments having another grade (for example a third grade) less fine, this bulk enveloping and being in contact with strainers for similar evacuation means to redirect the purified water out of the filtration chamber. This may be practical to avoid a delicate positioning of a bag on the lowest part of the chamber, and taking into account the bulk/interference linked to the presence of these evacuation means which may be distributed above the bottom of the box delimiting the chamber.

[0036] With this type of filter arrangement, it is possible to retain the primary packaging surrounding the glass, without generating waste - unlike single-use flexible plastic films used to enclose bulk filtration materials such as sand.

[0037] The filter bag may be of the type without openings for access to the glass fragments. The filter bag may have an appearance revealing the contents based on glass fragments, due to the fineness of the wire elements of the bag. In options for producing the bag, the wire elements constituting the bag may be such as:

- the maximum diameter (in section) of a wire element constituting the mesh of the bag may for example be less than 0.5 or 0.6 mm, for example less than 0.3 mm (30/100).

- each wire element is free of metallic material.

- the bag is free of cotton and/or free of stretchable textile fiber(s).

[0038] According to another aspect, there is provided a method of obtaining a filter unit as defined above, from sorted glass components or containers which preferably result from recycling, the method comprising the steps consisting essentially of:

- fragmenting the glass of the components to obtain angular glass fragments, by using a rotor system and/or by means of generating implosion of the components;

- discriminate a part of the fragments, preferably by sieving, in order to select glass fragments corresponding to a predefined grade; and

- pouring the fragments resulting from the selection into the interior volume of a water-permeable bag, as filtration members, preferably through a single opening (opening, typically wide, formed opposite a bottom zone or line) of said bag, before a step of closing the bag to obtain the filter unit.

Brief description of the drawings [0039] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the attached drawings, in which:

Figure 1 illustrates an integration, in a treatment circuit of a basin, of a water purification device according to one embodiment, with a multi-layer arrangement using filtration units each having a water-permeable bag-shaped envelope.

Figure 2A is a detailed view of a bag constituting the envelope of a filtration unit, with fine mesh capable of retaining glass fragments of size 1 mm or less.

Figure 2B shows a non-limiting example of mesh, here of the woven mesh type, used in the receiving portion of the bag where glass fragments constituting all or part of the filtration members are enclosed.

Figure 2C illustrates manual cleaning of each filter unit, which avoids backwashing in a closed chamber, which is costly in terms of water consumption.

Figure 3A is a view of a filtration chamber boundary box/housing, illustrating internal components of such a box.

Figure 3B illustrates, with views similar to that of Figure 3A, a phase of completion of filling of the filtration chamber, here with filter units arranged in a spiral pattern around or on the periphery of a purified water discharge pipe.

Figure 3C shows, in a detailed top view within the filtration chamber during the installation of the filter units, an example of assembly in crowns or rings of filter units, which are furthermore superimposed in layers to form at least two successive layers in the direction of filtration of the water.

Figure 4 schematically shows a detail of a filter unit according to an embodiment of the invention, with a fraction of the filtering members, including or consisting of glass, visible by transparency. Figure 5 schematically illustrates an example of equipment for obtaining and sorting glass fragments, typically non-cutting, allowing filling of bags with a particular grade of glass fragments, before their closure, for production of filter units with a filling essentially or exclusively based on glass. Figure 6 is an enlarged view of contained glass fragments forming the filtering members of each unit, showing the generally angular character of each of the fragments, with areas of crests or edges.

Description of embodiments

[0040] Hereinafter is a detailed description of several embodiments of the invention with examples and reference to the drawings. In the various figures, identical references indicate identical or similar elements. [0041] With reference to FIG. 1, there is illustrated a water filtration system 1 in connection with a basin 2, here filled with liquid water at a level sufficient to allow a treatment loop to be produced. The filtration system 1 may be a filtration group or assembly comprising a pump P, a filter body/box 11 delimiting a filtration chamber.

10, suction and discharge pipes (return line 6) allowing the circulation of water through the filter media (media contained in the chamber 10), in order to retain suspended matter in the raw flow of water to be purified. At least one end E1 of the pipes connects the system 1 to the basin, in order to bring the raw water (to be purified) into the box

1 1 . The pump P may optionally be interposed between such an inlet E1 and an inlet E provided on the box 11 . The pump P may include a pre-filter or be associated with a pre-filter used to retain large particles which could damage the mechanism of the pump P.

[0042] The system 1 may be of the type having a selection valve VS, in order to be able to choose whether or not to activate a filtration mode with circulation of raw water from the inlet to an inlet E of the filtration chamber 10. The selection valve VS is arranged directly on a filter head forming a cover C of the box 11 or may be coupled to the box 11 in a different manner. More broadly, the filtration system 1 may have a filtering arrangement enclosed in a box 11 provided with an inlet for water to be purified from the basin 2 and an outlet 7 communicating with the basin via a return line 6.

[0043] As visible in FIGS. 1 and 3B, one or more filter units 4, 104 can fill the filtration chamber 10, which makes it possible to introduce a filtration medium including angular glass fragments. In particular, each filter unit 4, 104 includes a bag 5 whose wall or walls are permeable to water, which makes it possible to retain a load of filter members M2, M3 including or consisting of the glass fragments which are angular, for example with a particular size range for these fragments in order to play a role as a filter medium.

[0044] The glass fragments are enclosed in an interior volume V5 of the bag, which may be the only useful volume delimited by a receiving portion of the bag 5. In variants, several interior volumes V5 may be formed in the same wrapping article to constitute a filtering unit (provided that each interior volume is delimited by a water-permeable wall). In addition to an angular geometry, the glass fragments have for example a reduced maximum dimension/size, generally less than or equal to 4 mm, preferably less than or equal to 2 mm, which may be a characteristic particle size corresponding to dry sieving. [0045] With reference to FIG. 2C or 3B, it is understood that the bag 5 can constitute the envelope, therefore defining the external surfaces, of the filter unit 4 or 104, typically with a certain overall flexibility of the bag 5. For example, each filter unit 4, 104 can easily bend and/or flatten, without stretching (or at least locally significant/perceptible stretching) of the wire elements 5f, 5g constituting the bag 5, when the filling level is not close to the level of a maximum filling. More generally, the bag 5 can be made of textile material, sewn or woven, to allow great deformability at a mid-filling compared to a maximum level. In uses in a housing or box 11 delimiting a filtration chamber 10 several tens of centimeters high, for example of a height greater than or equal to 45 cm, this ability to bend and deform can facilitate stacking of filter units 4, 104 one above the other.

In certain options, a filter unit 4, 104, which may have a generally parallelepiped format, for example during transport phases upstream of its use, may be deformed and, if necessary, curved to obtain a radius of curvature of less than 30 cm. This may facilitate a spiral or spiral arrangement of filter units 4, 104, as schematically shown in the non-limiting case of FIGS. 3B and 3C.

Example of a bag design

[0046] With reference to FIGS. 2A, 2B and 2C, the bag 5 can be designed by forming a mesh M5 making it permeable to water while being able to retain glass fragments of angular geometry, for example by limiting the mesh size to the submillimeter range and preferably with the ability to retain glass fragments whose grade falls to approximately 0.4 mm (lower limit) of the grade of the glass fragments contained in the bag 5.

[0047] To enable a robust filter unit 4, 104 to be obtained, the bag 5 may be sewn with thread(s) based on a rot-proof polymer material, in particular a polyester, preferably PET, which may be recycled PET. Another equivalent polymer may be chosen, i.e. a similar polymer or any polymer constituting a hard, rigid, solid and very chemically stable material, under the usual conditions of filtration of water (most generally water whose temperature is between 10 and 37°C).

[0048] The bag 5 can be obtained by connecting two walls 51, 52, which are for example separately designed parts, or possibly two portions of the same part folded over on itself. More generally, each part making it possible to design the bag 5 is obtained by producing a mesh of wire elements 5f, 5g, so that the bag 5 has a net structure. In exemplary embodiments, each bag 5 can have two substantially parallel edges. The bags 5 have for example peripheral connections making it possible to define a filling opening 05. The peripheral connections can include :

- a bottom connection 5a, opposite the edge 5b capable of delimiting the filling opening 05,

- and two parallel junctions 5c, forming the two parallel edges of the bag which can define the largest dimension of the bag.

A substantially parallelepiped format of the bag 5 can be obtained after filling with filtering members.

[0049] The bag 5 may have a 2D structure (for example with at least four coplanar sides before filling), which remains relatively flat so that the maximum thickness Em of a filter unit 4, 104 may be limited to less than 1 10 mm, for example less than 80 mm. This facilitates a layered arrangement of the filter units, for example obtaining at least 4 or 5 superimposed layers for a box whose filtration chamber height does not exceed 600 or 650 mm. Each bag 5 may have an elongated structure, the thickness Em not exceeding any of the other dimensions of the filter unit 4, 104.

[0050] Before filling, the bag 5 may have a temporary opening 05, delimited by an annular edge in a conformation spaced from two opposite walls 51, 52 delimiting the interior volume V5 of the bag 5. The two walls 51, 52 are joined at the parallel junctions 5c and by the bottom connection 5a or fold (intermediate fold between the two walls 51, 52), before filling. After filling, a connection 5d is made to connect two portions of the edge 5b which are respectively distributed in the first wall 51 and in the second wall 52.

[0051] As can be seen in particular in FIGS. 2A and 2B, the mesh M5 makes the walls 51, 52 permeable while limiting the sizes of the multiple lateral openings 3 (openings in the walls 51, 52) of the bag: this size is reduced to an order of magnitude close to or equal to that of the diameter of the wire elements 5f, 5g constituting the bag 5.

The bulk of glass fragments can be washed effectively by a jet of water passing through these multiple openings 3.

[0052] As visible in FIGS. 2A, 2B and 4 in particular, the bag 5 may have a sewn structure with:

- on the one hand, first wire elements 5f extending in a first direction D1, while being kept distant from each other in a second direction D2 distinct from the first direction D1,

- and on the other hand second wire elements 5g which are engaged with a plurality of the first wire elements 5f to form the mesh/mesh M5.

More particularly, the bag 5 has a weaved mesh structure, robust to withstand repeated uses (filtrations, washing), and compatible with the retention of fragments of glass of a particle size grade not exceeding 1.6 or 2 mm for the upper limit, as measured by dry sieving.

[0053] The threads of the structure of the bag 5 may have a density (linear mass) of, for example, between 40 Deniers and 65 Deniers. The Denier corresponds to the weight in grams of 9000 meters of thread. Each thread of the bag 5 may, for example, have a density of between 45 and 60 Deniers, being designed in a resistant plastic.

[0054] With this type of density, each of the bags 5 of the filter units 4, 104 can have good mechanical strength during handling or during impact (throwing on the ground for example), given the weight contained. More broadly, the robustness of the bags 5 remains compatible with maneuverability and flexibility to fit the shapes of the box 11 (in particular the interior of the walls) and allow regular stacking of each layer of filter units within a filtration chamber 10.

[0055] The plastic threads may, if necessary, be colored to facilitate identification of the grade of the glass fragments which are contained in the interior volume(s) V5 of the bag 5. In the filtration chamber 10, each type of bag may then have a particular color (for example Blue and Green), depending on the particle size of the glass fragments: distinct respective grades are then associated with each category of bags 5.

When a complementary medium, for example also fragments of glass with angular geometry, or gravel, are to be poured beforehand into the filtration chamber 10 to line the bottom of the box 11, this bulk can be packaged in bags which are not to be kept during filtration, these separate bags therefore being to be untied/opened by the user.

[0056] Such bags (not illustrated) may also have a particular color to avoid any risk of confusion with the bags 5 of the filter units 4, 104. Whether this packaging option is chosen or not, the bulk of the filter members M1 may include or consist of particles whose particle size may be in the range 1.6 mm to 4 mm, with typically 100% of the filter members M1 being coarser than the filter members contained in the interior volume of the filter units 4.

Non-limiting example of obtaining filter units

[0057] In embodiments, the material constituting the bag 5 can be recycled (such as rPET in particular), as can its contents, for example when it is exclusively angular glass fragments, preferably obtained after recovery of glass components/containers 30 (see FIG. 5) from a collection. An implosion treatment is typically used or another similar method of these glass components/containers 30, which limits/prevents the appearance of sharp edges. [0058] In Figure 5, it can be seen that the production of the units 4, 104 can be freed from new glass manufacturing, which involves recovering sand from the natural environment, where it tends to become scarce. Here, each of the fragments can be obtained from glass components or containers 30 that have already been manufactured and used to the point of becoming scrap. These are simply sorted containers 30 (which result from recycling). These containers 30 are for example conveyed by a conveyor 41 to a fragmentation station having means 42 for generating implosion.

[0059] After recovering glass components or containers, whether exclusively by recycling or not, the method first comprises:

- a fragmentation step 43 for fragmenting or crushing the glass of the components/containers 30, by using a rotor system and/or by means 42 for generating implosion of the components 30. This makes it possible to obtain angular glass fragments, typically by avoiding direct crushing. In some embodiments, obtaining fragments with sharp edges is avoided. Optionally, a sufficient rotor rotation speed is used to optimize the implosion effect, for example a speed greater than 1200 revolutions per minute as a non-limiting example.

[0060] The method for grouping the suitable glass fragments may then include:

- a selection step to discriminate a portion of the fragments, preferably by sieving using a multi-sieve system 44, in order to select glass fragments corresponding to a predefined grade (for example fragments not exceeding 1.6 mm as the upper limit of the grade);

- a pouring/discharging, via the opening 05, of the fragments resulting from the selection in the interior volume V5 of a water-permeable bag 5 having a mesh M5 suitable for retaining fine fragments, including those of submillimeter size, which may form the filtration organs; and

- a step of closing the bag 5 to obtain the filter unit 4; 104 ready for use.

If necessary, marking or coloring of threads can be carried out before the discharge of the glass fragments.

[0061] In order to obtain two categories of filter units 4, 104 or more, the multi-sieve system 44 can be configured to present several divergent paths, guiding the fragments to a final bagging station whose location depends on the type of discrimination carried out upstream (therefore the desired grade, the granulometry selected for these fragments).

Example(s) of installation of filter units in a pond filter [0062] With reference to FIG. 1 and FIGS. 3A-3B, the filter units 4, 104 may have an ability to deform, like a malleable material, knowing that, for a large majority of the filtration members, which are essentially glass fragments, the characteristic particle size is less than 1, 6 or 2 mm. At least two categories of filter units 4, 104 may be used, including:

- a first category of filter units 4 representing the lowest grade or finest particle size, typically in the submillimeter range, which in practice makes it possible to achieve the finest level of filtration, for example a filtration threshold of less than 10 micrometers;

- a second category of filter units 104 representing a less fine grade with a comparatively higher particle size, but which can achieve a correct level of filtration, for example by making it possible to separate particles which may have passed through the M5 mesh of the bag 5, typically particles having a size of less than 100 micrometers (the grade of these fragments can for example separate particles of a size greater than or equal to 10, 15 or 20 micrometers depending on the case).

[0063] Typically by comparison with the naked eye, it can be seen that the filtration members M2 of the units 4 are smaller than the filtration members M3 of the units 104, with for example the majority or most of the filtration members M3 consisting of angular glass fragments exceeding one millimeter. In Figure 6, it can be seen that the glass fragments have a geometry very different from a round piece or a sphere: they have an angular geometry, favorable for increasing the available surface area in the context of purifying a water flow. The characteristic dimension D4 or particle size diameter (by dry sieving) of the fragments is chosen to be small, in particular typically less than or equal to 2 mm, to accumulate a large number (for example greater than 5000 fragments) in each unit 4, 104.

[0064] In options, for equal bag size 5 (same internal volume V5), the number of glass fragments in the units 4 can be at least 3 or 6 times greater than that of the units 104. More generally, it is understood that each bag 5 has its own particle size range and that, depending on the space available in the filtration chamber and/or depending on the geometry of the bag, a stack can be obtained by distributing the bags corresponding to a fine particle size in a layer which can serve as a support for a following layer consisting of bags corresponding to a less fine particle size.

[0065] In the illustrated case, a lower part of the filtration chamber 10, at the level of which a drain plug BV may possibly be located, is reserved for a different filling of the filter units 4, 104. In the lower space of this chamber 10, not intended to receive the filter units 4, 104, a bulk of first filtration members M1 (solid members for mechanical filtration) is arranged to form a coating around water re-suction parts (typically strainers 9, as visible in Figure 3A before any filling).

[0066] As a non-limiting example, the first filtration members M1 are glass fragments of a higher grade (less fine) than that of the glass fragments of the first category of filter units 4 and optionally higher than that of the glass fragments of the second category. It is understood that these first filtration members M1 can be poured into the filtration chamber 10 to form a low filtration layer in the box 11, which is the layer furthest from the inlet E of the filter. The inlet E can be located in a filter head or cover C making it possible to close the upper opening O of the box 11. The upper opening O can be axial, opposite a base S of the box, or be located at least partly on one side.

[0067] The opening O, with circular or annular delimitation, generally has a diameter greater than 90 or 100 mm, much wider than a bottle neck, in order to facilitate filling operations. Regardless of the precise shape and dimensions of the opening O, each filter unit 4, 104 may optionally have a short side (smaller than a long side of the corresponding bag 5) forming a width which may be less than or equal to the diameter of the opening O, which facilitates its passage into the chamber 10.

[0068] The filter units 4, 104 may be part of a kit comprising several bags filled with glass fragments, one type of which (if necessary provided with an opening system facilitating the obtaining of an opening on a predetermined side of the bag) may correspond to the bags to be opened to pour out the first filtration members M1, while the other types of bags may be the sewn bags 5, which are to be kept intact for maintaining the glass fragments in the respective interior volume V5 of different filter units 4, 104.

It is understood that the different parts of the kit can be put in place in the box 11 of the filtration system 10 when the box 11 is empty or at least sufficiently emptied and cleaned to allow new water treatment/purification cycles to be started by filtration through the filter units 4, 104.

[0069] With reference to FIG. 3A and 3B, an example of using filter units installed in a filtration chamber 10 is shown to enable a high-performance filter arrangement to be obtained. In this case, a prefilter layer 8p is illustrated as being obtained by installing units 104, the filtration members of which correspond to a less fine grade of filtration than that permitted by the filter units 4 placed further downstream in the direction of circulation of the fluid to be purified.

[0070] When a central pipe T is provided in the filtration chamber 10, for the circulation of clean water towards the discharge line/conduit 6 via an outlet 7 of the cover C, there is an open upper end of this pipe T which is accessible via the opening O as soon as the cover C is removed. A temporary plug BP (visible in figure 3A) can optionally be provided to close such an open end of the pipe T, before starting the filling of the chamber 10.

[0071] A filtering arrangement can selectively use the filtering units 4 of the first category, in an intermediate filtration layer 8f, for example placed on the filtration members M1 from the first bags of the kit (and poured in bulk on the bottom). The filtering units 4 are arranged by the user in a spiral pattern, so as to form an annular layer around the pipe T, or more generally in any suitable manner to form a homogeneous, stepped filtration layer based on a media consisting of angular glass fragments, a large part of which is submillimeter in size.

Here an inlet E is illustrated being located higher than any of the filter units 4, 104 but, alternatively, different arrangements may be adopted, for example if the direction of flow in the chamber 10 is not generally vertical and/or if the inlet is positioned differently.

[0072] The user can flatten the bags 5 of the filter units 4 and form two sub-layers or stages in the layer 8f which makes it possible to obtain the finest level of filtration. A comparable installation can be carried out by manipulating the bags 5 of the filter units 104, by promoting the overlap between bags 5, over their length as well as over their width. In each layer 8f, 8p of respective filter units 4, 104, it can be provided to form an inner ring A1 surrounded by an outer ring A2, each of these rings A1, A2 being composed of identical/same type filter units, as visible in the non-limiting case of FIG. 3C. In certain options, geometric/bag size variations can be adopted within the same category of filter units, for example with one or a few shorter bags to facilitate obtaining the ring conformation.

[0073] The layer of filter units 4 is an intermediate layer 8f between the base layer 8b formed or including the first filtration members M1 arranged in bulk, without a casing, and an upper layer 8p with a pre-filter effect making it possible to avoid a risk of early clogging in the layer 8f. More broadly, for a given direction of circulation (here generally vertical) of the water to be purified conveyed via the inlet E, the water can first pass through filter units 4 which have been deposited near the inlet E so that a first fraction of particles are separated, according to a first given filtration level, before passing through the filter units 104 filled with fragments of glass of another grade (finer), at the level of the layer 8f which defines the finest level of filtration, finer than the first level. [0074] With reference to FIG. 1 , the water may come from a basin such as a swimming pool or the like and the filter arrangement combining the filter units 4, 104 may be constituted in a filtration chamber 10 of a sand filter (initially intended for operation with sand as filter load). The use of filter units 4, 104 with glass fragments makes it possible to benefit from the self-sterilization properties of glass without risk of degradation of the filtration media and with ease of handling when the filtration system 1 is stopped.

In operation, the purified water having passed through the filtration arrangement composed of the filter units 4, 104 can pass through a low filtration layer composed of the filtration members M1 (as visible in figure 3B with the arrows F) and return to the basin 2 (see arrow F’ and return line 6).

[0075] It should be apparent to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed.

Thus, although the figures show an example of integration of filter units in a box without fixing the bags (which can be placed/superimposed), other integrations can be envisaged, for example with the use of guides and/or fixing parts to allow a predetermined or globally determined positioning in the filtration chamber.

[0076] In particular embodiments, one or more filter units may, if necessary, be integrated into a hollow external component which is in the form of a cartridge or packaging with inter-unit fixing means, for example with a fixing flange or clamp, or other interconnecting members. This may, if necessary, improve the adaptation to a particular receiving box, by further facilitating the efficient installation of the filter units.

In options, a foolproofing system or guiding means, provided or installed in the box 11, make it possible to position a first type of filtering units in a suitable sub-zone or compartment of the box, for example above a lower compartment filled with bulk glass fragments.

Claims

[Claim 1] Filter unit (4; 104) of a water filtration system (1) for a pond (2), capable of filling all or part of a filtration chamber (10), the filter unit (4; 104) comprising: - a bag (5) which has a wall, permeable to water, making it possible to delimit an interior volume (V5); - filtration members forming a bulk mass (M2; M3) capable of being crossed by the water of the basin (2); characterized in that the filtration members comprise glass fragments and are held in the interior volume (V5) by the bag (5) which is a closed bag defining a filter bag, the glass fragments each having a non-round and angular geometry, a maximum dimension of the glass fragments being less than or equal to 4 mm, preferably less than or equal to 2 mm. [Claim 2] A filter unit according to claim 1, wherein the bag (5) is a textile bag, the closed configuration of which is adapted to allow the filter unit (4; 104) to be mounted as a single unit in the filtration chamber (10), and respectively to be removed as a single unit; and wherein at least 95% of the mass of the glass fragments is distributed in glass fragments having a particle size, measured by dry sieving, which is greater than or equal to 0.4 mm. [Claim 3] A filter unit according to claim 1 or 2, wherein the glass fragments represent at least 60% by weight of the bulk mass, the glass fragments having sharp edges and angles of less than 140°, and wherein the mesh of the bag (5) is submillimetric for a barrier effect retaining the smallest glass fragments contained in the filter unit (4, 104). [Claim 4] Filter unit according to any one of the preceding claims, wherein the bag (5) is sewn with thread(s) based on a polymer material, in particular a polyester, preferably PET, and wherein the filling of the interior volume (V5) by the filtering members is partial to allow the filter unit (4; 104) to be deformable with an ability to bend, preferably so that the bag (5) can be curved with a radius of curvature of less than 30 cm. [Claim 5] A filter unit according to any preceding claim, wherein the bag (5) has a sewn structure which has: - first wire elements (5f) extending in a first direction (D1), and which are preferably spaced apart from each other in a second direction (D2) distinct from the first direction (D1), and - second wire elements (5g) which engage with a plurality of the first wire elements (5f) to form a mesh. [Claim 6] A filter unit according to any preceding claim, wherein a textile material of the bag (5) which delimits the interior volume (V5) has a warp-weave mesh structure. [Claim 7] Filter unit according to any of the preceding claims, in which a textile material of the bag (5) which delimits the interior volume (V5) is designed using threads which have a density ranging from 40 Deniers to 65 Deniers. [Claim 8] A filter arrangement for use in a pond water filtration system (2), and capable of purifying liquid pond water, the arrangement comprising a plurality of filter units (4, 104) as defined in any preceding claim, wherein the arrangement includes a staggered arrangement of the filter units (4, 104), in a filtration chamber (10) of the water filtration system, making it possible to distribute contact surfaces formed by the glass fragments in the various filter units (4, 104), knowing that a particle size, determined by dry sieving, of the glass fragments present in at least part of the bags (5) of the filter units (4, 104) corresponds to an interval bounded by: - a first submillimeter dimension forming a lower limit of the interval, - and a second dimension, forming an upper limit of the interval, which does not exceed 1 or 2 mm. [Claim 9] A filter arrangement according to claim 8, wherein one or more of the filter units (4) define an intermediate filtration layer (8f) in which the glass fragments, preferably provided with the finest grade in the arrangement, allow a greater filtration fineness, compared to/with: - a pre-filter layer formed by at least one other filter unit (104) located closer to an access inlet (O) of the chamber (10) for the introduction of the liquid water to be purified; and - a bulk of glass fragments poured without wrapping into an outlet region, which is preferably at the bottom of the filtration chamber and/or in a region located lower than the intermediate layer in the chamber. [Claim 10] A method of obtaining a filter unit as defined in any one of claims 1 to 7, from sorted glass components or containers (30) which preferably result from recycling, the method comprising the steps essentially consisting of: - fragmenting (43) the glass of the components to obtain angular glass fragments having a maximum dimension less than or equal to 4 mm„ by using a rotor system and/or by means (42) for generating implosion of the components (30); - discriminate a part of the fragments, preferably by sieving, in order to select glass fragments corresponding to a predefined grade; and - pouring the fragments resulting from the selection into the interior volume (V5) of a water-permeable bag (5), as filtration members, preferably through a single opening (05) of said bag, before a step of closing the bag to obtain the filter unit (4; 104).