WO2023118428A1

WO2023118428A1 - Self-cleaning filtering device

Info

Publication number: WO2023118428A1
Application number: PCT/EP2022/087466
Authority: WO
Inventors: Pascal Crepet
Original assignee: Id Invention & Développement
Priority date: 2021-12-23
Filing date: 2022-12-22
Publication date: 2023-06-29
Also published as: FR3131221A1

Abstract

The invention relates to a filtering device comprising: a main duct (20) receiving a flow of fluid to be filtered, a first filter (12) in the form of a screen comprising a first set of parallel rods (12b) arranged across the main duct, and a second set of rods (12a) maintained parallel to one another and disposed across and against the rods of the first set, the rods of the second set of rods being movable with respect to the rods of the first set of rods, and a drive device (31-33) for moving the rods of the second set of rods between a debris collection chamber (25) and an opposite position, on either side of the main duct, such that debris retained by the rods of the first filter can be moved to the collection chamber.

Description

Title of the invention: SELF-CLEANING FILTERING DEVICE

The present invention relates to the collection of solid waste floating in bodies of water such as oceans, seas, or entrained in a flow of water, such as a stream, a river, a river, a channel , or a pipeline.

It is known to place a filter for this purpose across a flow of water, the filter having the form of a sieve or a grid formed of parallel bars spaced apart by a distance less than the size of the debris at collect. However, this solution leads to progressive, more or less rapid clogging of the filter depending on the density of the debris entrained in the water flow. It is therefore necessary to ensure continuous or periodic cleaning of the filter.

Patent FR 2 609 643 describes a filtering device formed of mobile filtering panels, articulated in pairs, like the links of a chain closed on itself and driven in rotation by a wheel. The filter panels are formed by parallel channels having a hydrodynamic profile. A fixed cleaning device projects water against the current, to expel the debris retained by the filter towards a drainage channel. By rotating, the filter panels pass successively in front of the cleaning device. As a result, the filter panels pass through the flow twice, which multiplies the drag due to the presence of the filter in the flow and therefore reduces the filtered flow rate of the flow. In addition, some debris may pass through the portion of the filter panels located upstream, relative to the flow, but be retained by a filter panel located downstream and wrap around a strand forming the mesh of the filter panel when the latter returns to the downstream position. It is then difficult to extract such debris from the filter panel.

EP 0 440 573 describes a filter in the form of a grid with vertical bars and a comb for cleaning the filter. The comb is vertically movable and rotating. The comb teeth are deployed between the bars on the way up to clean the filter, rotate at the end of their stroke to eject debris and are retracted on the way down to the base of the bars where they are deployed again for a new cleaning cycle . The use of such a cleaning device in the form of a comb implies that the filter has the form of a grid with parallel bars. However, such a filter is capable of passing debris having an elongated shape of width less than the spacing of the bars and of length greater than this spacing. Such a filter therefore has less filtering efficiency than a filter in the form of a sieve. It is therefore desirable to provide a screen filtering device associated with a filter cleaning device. It is also desirable to increase the flow rate of the filter without increasing the surface or the width of the meshes thereof.

Embodiments relate to a filtering device comprising: a main conduit receiving a flow of fluid to be filtered, and a first screen-shaped filter comprising a first set of parallel rods, arranged across the main conduit, and a second set of rods held parallel to each other and arranged across and against the rods of the first set to form the meshes of the sieve, the rods of the second set of rods being movable relative to the rods of the first set of rods, and a drive device for moving the rods of the second set of rods to at least one debris collection chamber, for moving debris retained by the first screen filter into the collection chamber.

By "main pipe receiving a flow of fluid to be filtered" is meant here and in the context of the invention, a physical pipe, such as a hollow profile, a channel, or a pipe, fixed or moving in a volume of fluid, or a natural passage delimited by all or part of the volume of fluid itself, such as a volume of water, in particular a sea, a watercourse, a river, a river, a lake.

A collection chamber according to the invention can be submerged or outside the volume of fluid of which a flow is to be treated. A collection chamber can for example be submerged in a position lateral to the main duct. A collection chamber can also be arranged in an area with ambient air or in a container outside the fluid volume.

According to one embodiment, the rods of the second set of rods are fixed together in an endless loop stretched between pulleys.

According to one embodiment, the collection chamber is located outside the main duct, a device for cleaning the rods of the second set of rods being arranged in the collection chamber.

According to one embodiment, the device comprises a plate provided with a comb and movable in the collection chamber between two opposite positions comprising an evacuation position towards a debris evacuation conduit and an opposite position, the plate being held in an extended position where the comb is introduced between the rods of the second set of rods when the tray is moved to the evacuation position, and in a retracted position when the tray is moved to the opposite position, the plate being configured to lead to the evacuation duct of the debris entrained by the rods of the second set of rods.

According to one embodiment, the plate comprises teeth arranged to slide in a groove formed in each of the rods of the second set of rods.

According to one embodiment, each of the rods of at least some of the rods of the second set of rods comprises hooks arranged along the rod on areas of contact with the rods of the first set of rods, to drive towards the chamber collection, debris wrapped around the rods of the first set of rods, the hooks engaging in a groove formed in the rods of the first set of rods.

According to one embodiment, the device comprises a second filter formed by a third set of parallel rods fixed across the main duct, and a downstream part relative to the fluid flow, of the rods of the second set, the rods of the second set being fixed together in an endless loop, the rods of the downstream part of the rods of the second set being in contact with the rods of the third set of rods, to move debris retained by the second filter towards a collection chamber.

According to one embodiment, each of the rods of at least part of the second set of rods comprises hooks arranged along the rod on areas of contact with the rods of the third set of rods, to lead towards the collection chamber , debris wrapped around the rods of the third set of rods.

According to one embodiment, the rods of the first set of rods are spaced apart from each other by a distance greater than or equal to a spacing distance of the rods of the second set of rods, and/or the rods of the third set of rods are spaced from each other by a distance less than the spacing distance of the rods of the second set of rods.

According to one embodiment, the rods of the first set of rods are fixed at one end on the collection chamber side via an L-shape extending downstream in the direction of the flow, in order to allow debris driven by the rods of the first set of rods to be driven towards the collection chamber without being sheared and without blocking the advancement of the rods of the second set of rods, or the rods of the first set of rods are fixed only at one end opposite the collection chamber.

According to one embodiment, the device comprises: a fourth set of parallel rods arranged upstream of the first set of rods, and/or a screen arranged downstream of the second set of rods, the mesh width of the sieve being less than a spacing distance of the rods of the second set of rods or the rods of the third set of rods.

According to one embodiment, the rods of at least one of the sets of rods have a tapered cross section.

According to one embodiment, the main conduit comprises: an inlet opening receiving the flow of fluid, an outlet opening, a downstream section channeling the flow of fluid towards the outlet opening, the outlet opening presenting a surface lower than a surface of the inlet opening, the surfaces being considered in a plane perpendicular to a longitudinal axis of the main duct, and an upstream section channeling the flow of fluid to be filtered having entered the main duct towards the first and second sets of rods, the main duct having one or more of the following characteristics: the upstream section has, in a plane passing through the longitudinal axis of the main duct, an internal profile forming with the direction of the flow or the longitudinal axis of the main duct an angle nil or between 0 and 16°, and/or the downstream section has, in a plane passing through the longitudinal axis of the main duct, a straight or curved internal profile and forming with the direction of the flow an angle between 0 and 20, and preferably between 4 and 9°, and/or the surface of the outlet opening is adjusted so that the speed of the fluid flow leaving the main conduit is between 80 and 110% of the speed of the fluid around the exit opening, and/or the surface of the exit opening is comprised between 0.1 and 5 times the total passage surface of the fluid through the first and second sets of rods, and/or the section upstream of the duct has a bulge on its outer face.

According to one embodiment, the main duct has a section of circular, elliptical, trapezoidal, triangular, polygonal, square or rectangular shape, or a shape composed of these shapes.

Embodiments may also relate to a filtering system comprising a plurality of filtering devices such as the one defined above, fixed side by side across a flow of fluid.

According to one embodiment, the filtering devices are arranged in a primary conduit comprising: an inlet opening receiving the flow of fluid, an outlet opening, a downstream section channeling the flow of fluid towards the outlet opening, the outlet opening having a surface smaller than a surface of the inlet opening, the surfaces being considered in a plane perpendicular to a longitudinal axis of the primary duct, the primary duct having one or more of the following characteristics: the upstream section has, in a plane passing through the longitudinal axis of the primary duct, an internal profile forming with the direction of the flow or the axis longitudinal of the primary conduit an angle of zero or between 0 and 16°, and/or the downstream section has, in a plane passing through the longitudinal axis of the primary conduit, a rectilinear or curved internal profile and forming with the direction of the flow an angle comprised between 0 and 20, and preferably between 4 and 9°, and/or the surface of the outlet opening is adjusted so that the speed of the fluid flow at the outlet of the primary conduit is between 80 and 110 % of the fluid velocity around the outlet opening, and/or the area of the outlet opening is between 0.1 and 5 times the total fluid passage area through the first and second sets of rods , and/or the upstream section of the primary duct has a bulge on its outer face.

Examples of embodiments of the invention will be described in the following, on a non-limiting basis in relation to the appended figures, among which:

[Fig.l] Figure 1 is a longitudinal sectional view of a filter device, according to one embodiment, Figures IA, IB are sectional views along perpendicular sectional planes of part of a filter of the filtering device, according to one embodiment,

[Fig.2] Figure 2 is a partial longitudinal sectional view along section plane AA shown in Figure 1, of the filter device according to one embodiment,

[Fig.3] Figure 3 is a top view of a plate for cleaning the debris present on the second filter, according to one embodiment,

[Fig.4] Figure 4 is a partial longitudinal sectional view of the filter device, along the section plane BB shown in Figure 1, according to one embodiment, Figures 4A, 4B are sectional views along perpendicular section planes of a part of a filter cleaning device of the filtering device, according to one embodiment,

[Fig.5] Figure 5 is a longitudinal sectional view of part of a filter of the filtering device, according to one embodiment,

[Fig.6] Figures 6, 6A, 6B are front views, and in profile section along two perpendicular directions of part of a second filter of the filtering device, according to one embodiment, [Fig.7] Figure 7 is a front view of part of a third filter of the filtering device, according to one embodiment,

[Fig.8] Figure 8 is a longitudinal sectional view of a filter device, according to another embodiment,

[Fig.9] Figures 9A, 9B are sectional detail views along perpendicular section planes of part of a filter of the filtering device of Figure 8, according to one embodiment,

[Fig.10] Figures 10A and 10B are sectional detail views along perpendicular section planes of part of a filter of the filtering device shown in Figure 8, according to one embodiment,

[Fig.11] Figure 11 is a detail view in section of part of a filter of the filtering device shown in Figure 8, according to another embodiment,

[Fig.12] Figures 12A, 12B are sectional detail views along perpendicular section planes of part of a filter of the filtering device of Figure 8, according to one embodiment,

[Fig.13] Figure 13 is a longitudinal sectional view of part of a filter of the filtering device of Figure 8, according to one embodiment,

[Fig.14] Figures 14, 14A, 14B are front views, and in section along two perpendicular directions of part of a second filter of the filtering device of Figure 8, according to one embodiment,

[Fig.15] Figures 15, 15A, 15B are front views, and in profile section along two perpendicular directions of part of a third filter of the filtering device of Figure 8, according to one embodiment ,

[Fig.16] Figure 16 is a front view of part of a fourth filter of the filter device of Figure 8, according to one embodiment,

[Fig.17] Figure 17 is a perspective view of a filtering device, according to one embodiment,

[Fig.18] Figure 18 is a longitudinal sectional view of the filter device of Figure 16, according to one embodiment, [Fig.19] figure 19 is a front view of a filtering system, according to one embodiment, [Fig.20] figure 20 is a side view of the filtering system of figure 18, according to a embodiment,

[Fig.21] Figure 21 is a side view of a filtering system, according to another embodiment,

[Fig.22] Figures 22 and 22A are front views and in longitudinal section of a filtering system, according to another embodiment,

[Fig.23] Figures 23 and 23 A are front views and in longitudinal section of a filtering system, according to another embodiment.

[Fig.24][Fig.25] Figures 24 and 25 are perspective and longitudinal section views of a filtering device, according to another embodiment,

[Fig.26] Figure 26 is a perspective view of a filter device, according to another embodiment.

Figures 1 and 2 show a filter device 1 according to one embodiment. The device 1 comprises a tubular duct 20 having an inlet opening 21 and an outlet opening 22, and three successive filters 11, 12, 13, the filter 11 being arranged upstream in front of the inlet opening 21, and the filters 12 and 13 being arranged in the tubular conduit 20 so as to receive the flow of fluid 2 to be filtered.

However, it should be noted that one and/or the other of filters 11 and 13 can be omitted.

The second filter 12 comprises fixed parallel rods 12b distributed over an entire internal width of the duct 20 and movable parallel rods 12a, arranged perpendicular to the fixed rods 12b and against the latter to form meshes of a sieve. The rods 12a are movable in the axial direction of the fixed rods 12b, in order to cause the debris 3 retained by the rods 12b towards a chamber 25 for the evacuation of debris 3.

The rods 12a are fixed to each other at their two ends by cables 34 driven in rotation around pulleys 31, 32, 33. In the example of FIGS. 1 and 2, the pulleys comprise on one side of the duct 20 two pulleys 32, 33 and on the other side of conduit 20, a larger pulley 31, one of the pulleys being driven in rotation by a motor. Of course, the pulley 31 can be replaced by two smaller pulleys to obtain a more compact device. The chamber 25 can house a plate 35 arranged to move back and forth in a direction parallel to the rods 12a, in order to cause the debris 3 retained and carried by the rods 12a towards an evacuation conduit 26 .

It should be noted that on their way back, the rods 12a present less drag than the filter 12 due to the absence of the rods 12b. Chamber 25 is outside of fluid flow 2.

The filtering device 1 can also comprise a device for cleaning the filter 11. The cleaning device can for example comprise a comb 15 moving along the rods 11 in a direction in the deployed position where the teeth of the comb are arranged between the rods , and in an opposite direction, in the retracted position where the teeth of the comb are arranged parallel to the rods 11. The comb 15 can also be moved in a back-and-forth movement while being held in the deployed position between the rods 11. The Debris entrained by comb 15 can be collected in one or two threads on either side of the duct or not be collected.

The filtering device 1 can also comprise a suction device 41 for debris 3′ retained by the filter 13, to clean the latter and evacuate the debris sucked up to an evacuation duct 27. A head of the suction device is mounted movable transversely along rods 42 (for example endless screws). The rods 42 are movable transversely in a direction perpendicular to the rods 42, in order to be able to move the suction head over the entire surface of the filter 13 receiving the flow 2. When stopped, the suction device 41 can be stored outside the conduit 20 so as not to impede the passage of the flow of fluid 2.

The filtering device 1 can also comprise a system of doors 21a, 21b, 21c, 21d to allow the rods 12a to pass through the walls of the duct 20 in the vicinity of the pulleys 31, 32, 33. Each of the doors 21a-21d can be open under the effect of the movement of a rod 12a and close under the effect of elastic return means.

Figures IA, IB represent part of the rods 12a, 12b of the filter 12, according to one embodiment. At least part of the rods 12a comprises, in the zones of contact with the fixed rods 12b, one or more hooks 12c which slide in a longitudinal groove 12d formed in the rods 12b when the rods 12a are driven in translation in a direction parallel to the rods 12b. The hook 12c makes it possible to push towards the plate 35 the debris retained by the rods 12b and in particular the elongated debris likely to wrap around the rods 12b. The rods 12a can include several hooks 12c distributed over their length. The hooks 12c can be distributed over the rods 12a so that each rod 12b is in contact with at least one hook 12c.

FIG. 3 represents the plate 35, according to an exemplary embodiment. The plate 35 is formed by a grid, a comb 39a, 39b being formed at one end of the plate 35. The plate 35 may have meshes of width adapted to entrain the debris retained by the filter 12. In the example of the figure 3, the comb comprises seven teeth 39a extending between eight adjacent rods 12a of the filter 12 and eight shorter teeth 39b, coming into contact with these eight rods 12a, to evacuate the debris retained by the latter and in particular shaped debris elongated wrapped around them. The plate can form a dihedron so that the teeth 39a, 39b of the comb form an angle of between 30 and 60° with respect to the plane of the plate 35 in the direction of the evacuation duct 26. In this way, the teeth 39b in contact with the rods 12a are inclined towards the latter in the direction of movement of the tray towards the exhaust duct 26. A portion at the end of each of the teeth 39a extending between the rods 12a can extend parallel to the tray 35 .

FIG. 4 represents the transverse chamber 25 extending from one side of the conduit 20 close to the two pulleys 32, 33, and opening into the evacuation conduit 26. FIG. 4 also represents the plate 35 in different positions in the chamber 25. The chamber 25 is open on the side of the rods 12a on the duct 20. The plate 35 is driven in translation from an extreme position 35a to an extreme position 35b (for example from bottom to top), between the two opposite sides of the chamber 25, while the rods 12a are held momentarily fixed, the plate 35 being held in a deployed position to entrain with the aid of the teeth 39a, 39b debris 3" (FIG. 4B) retained by the rods 12a towards the evacuation duct 26. Having arrived at the evacuation duct 26 (in position 35b), the debris retained by the plate 35 is evacuated towards the duct 26, for example by suction.Then, the plate 35 tilts into a retracted position 35c to position itself along a wall of the chamber, where the comb is completely free of the rods 12a, then is driven in translation in the other direction (position 35d). During the return translation of the plate 35 in the retracted position towards the extreme position 35a, the rods 12a are again driven in translation by the pulleys 31-33 until a new cleaning phase of a certain number of following rods 12a , corresponding to the number of comb teeth. Arrived at the lower stop (positions 35d, 35a), the plate 35 tilts in the other direction to return to the deployed position where the comb is placed between the rods 12a, the movement rods 12a then being stopped. When the plate 35 unfolds, from position 35d to position 35a, the teeth 39a scrape the bottom of the chamber 25, which makes it possible to collect debris which would have entered the chamber 25 under the plate 35. The teeth 39a allow also to recover debris which would have passed between the rods 12a in the chamber 25, because the rods 12b stop at the entrance to the chamber 25. The plate 35 can be maintained in position 35c in which it does not interfere not with the hydrodynamics of the system, and this all the more so since the chamber 25 is located outside the conduit 20 through which the fluid flow 2 passes.

Rods 12b may be straight and attached only at their ends opposite chamber 25. L-shaped in order to allow the debris entrained by the hooks 12c to be entrained towards the chamber 25 without being sheared and without blocking the advancement of the rods 12a.

The movement of the plate 35 can be controlled by means of one or more studs 37 moving in a slideway 36 extending along a wall of the chamber 25 in a longitudinal direction of the latter, and of a rod 38 secured to the plate 35 and sliding in side slides (not shown) of the chamber 25, the positions of the tenon 37 and of the rod 38 being controlled by a mechanism (not shown).

Figures 4A, 4B represent one of the rods 12a and a tooth 39b of the comb formed at one end of the plate 35. During their transit through the chamber 25, each of the rods 12a comes into contact with a respective tooth 39b of the plate 35, the teeth 39b being inclined towards their end in the direction of the evacuation duct 26. When the plate 35 is driven towards the evacuation duct 26, the debris 3" liable to be wound around the rods 12a can thus be entrained by teeth 39b.

Figures 5, 6 and 7 show in more detail a part of each of the three successive filters 11, 12, 13. Figure 5 shows two rods of the first filter 11, according to one embodiment. Each of the filter rods 11 may be spaced from adjacent filter rods by a distance LU. Each of the filter rods 11 may have a hydrodynamic profile, with a rounded leading edge and a tapered trailing edge, to reduce the drag of the first filter.

FIGS. 6, 6A, 6B show movable 12a and fixed 12b rods of the second filter 12, according to one embodiment. The movable rods 12a are spaced apart by a distance W12, and the fixed rods 12b are spaced apart by a distance L12. The stitches of filter 12 thus have dimensions L12 x W12. In the example of Figures 6, 6A, 6B, the movable rods 12a have a circular profile and the fixed rods 12b a hydrodynamic profile, with a rounded leading edge and a tapered trailing edge, to reduce the drag of the second filter .

FIG. 7 represents the filter 13, according to one embodiment. In the example of figure 7, the filter 13 is in the form of a sieve with square meshes of width L13. The meshes of the filter 13 can be formed by rods of round or profiled section. Of course, any other mesh shape for the filter 13 may be suitable, such as a honeycomb shape.

According to one embodiment, the rods 12a are arranged vertically in the water flow 2 and are moved in a horizontal direction, while the rods 12b are arranged horizontally. In this way, the rods 12a horizontally lead the debris retained by the filter 12 towards the chamber 25. The rods 11 can be arranged indifferently in any direction.

The rod cleaning device 12a comprising the plate 35 movable in a back and forth motion can of course be omitted or replaced by any other suitable device, such as a debris suction device. The cleaning of the rods 12a can also be carried out manually during maintenance operations of the filtering device 1.

According to one embodiment, the ratio between the spacings between the rods or the width of the meshes of each pair of consecutive filters (11, 12), (12, 13) can be between 2.5 and 3.5. In an exemplary embodiment, the spacing between the rods 11 is between 2.5 and 5 cm, the spacing between the rods 12a and between the rods 12b is between 1 and 2 cm, and the width of the filter mesh 13 is between 0.3 and 0.6 cm.

FIG. 8 represents a filtering device 10 according to another embodiment. The filtering device 10 differs from the filtering device 1 in that it comprises a fourth filter 14, formed by the rods 12a which pass back into the flow 2 downstream of the filter 12 and fixed rods 14a arranged across the flow 2 perpendicularly to the rods 12a and against and downstream of the latter. The rods 12a and 14a thus form a screen filter 14. Thus, the filtering device 10 takes advantage of the endless return of the rods 12a to form a fourth filter capable of carrying the debris retained towards a chamber 125 parallel to the chamber 25 and arranged on the other side of the conduit 20, and therefore outside the conduit through which the fluid flow 2 passes. In addition, the filter 13 is replaced by a filter 113 arranged downstream of the rods 14a. Rods 12a can also be replaced by rods 112a with profiled section, in oblong shape, the sets of rods 12b, 112a then forming a filter 112.

The cleaning of the rods 112a after their passage over the rods 14a can be ensured by a second plate 135 movable in the chamber 125 to evacuate the debris retained by the filter 14. The plate 135 can have substantially the same shape as the plate 35 and be controlled so as to follow the same movements as the plate 35. The plate 135 in the form of a grid can have meshes of a width adapted to entrain the debris retained by the filter 14. The plate 135 can be replaced by another cleaning device, for example a suction device moving back and forth along the rods 112a.

Figure 8 also shows motors 43 provided to move the suction device 41 over the surface of the filter 113.

The filtering device 10 can also comprise a system of doors 121a, 121b, 121c, 12 Id to allow the rods 112a to pass through the walls of the conduit 20 in the vicinity of the pulleys 31, 32, 33. Each of the doors 121a-121d can be open under the effect of the movement of a rod 112a and close under the effect of elastic return means. Pulley 31 can also be replaced by two pulleys, such as pulleys 32, 33 to limit the size of filtering device 10.

In the event that the rods 14a are insufficiently rigid to remain pressed against the rods 112a upstream, to resist the pressure of the flow 2, stiffeners may be provided placed downstream of the rods 14a and fixed to them at different points. distributed along their length. According to another embodiment, the rods 14a are placed upstream of the rods 112a.

Figures 9A, 9B show rods 112a, 12b of filter 112 in more detail, according to one embodiment. Some or all of the rods 112a include, in areas of contact with the fixed rods 12b, a hook 112c which slides in the longitudinal groove 12d formed in the rods 12b. The hook 112c makes it possible to push towards the plate 35 the debris of elongated shape likely to wrap around the rods 12b.

Figures 10A, 10B show rods 112a, 14a of filter 14, according to one embodiment. The rods 112a comprise, in zones of contact with the fixed rods 14a, a hook 112e to push towards the plate 135 the debris 3a of elongated shape likely to wrap around the rods 14a. The hook 112e can be replaced by a simple point or a shape that matches the upstream part of the rod 14a. FIG. 11 represents part of the rods 112a, 14a of the filter 14, according to one embodiment. In FIG. 11, the hook 112e is replaced by a T-shaped hook 112g, the horizontal part of the T-shaped hook being engaged in a groove 14c of complementary shape formed in the rod 14a. The hooks 112g present on the rods 112a thus make it possible both to entrain the debris wound on the rods 14a and to hold the latter against the rods 112a.

Figures 12A, 12B show in detail the end of a tooth 39b of the plate 135, and a stem portion 112a, according to one embodiment. When the plate 135 moves towards a debris evacuation duct similar to the duct 26, the end of the tooth 39b can slide in a groove 112f formed in the rod 112a, in order to be able to drive towards the debris evacuation duct 3b which could have wrapped around the rods 112a.

Figures 13, 14, 15 and 16 show in more detail a part of each of the four successive filters 11, 112, 14, 113. Figure 13 shows two rods of the first filter 11 of the filtering device 8, according to one embodiment . The filter rods 11 can be spaced apart by a distance L21. Each of the filter rods 11 may have a hydrodynamic profile, with a rounded leading edge and a tapered trailing edge, to reduce the drag of the first filter.

Figures 14, 14A, 14B show movable 112a and fixed 12b rods of the second filter 12, according to one embodiment. The movable rods 112a are spaced apart by a distance W22, and the fixed rods 12b are spaced apart by a distance L22. The meshes of the filter 12 thus have dimensions L22×W22. In the example of Figures 14, 14A, 14B, the movable rods 112a have a tapered profile symmetrical with respect to a median transverse plane, the rods 112a being placed in the stream 2 in two opposite directions. The fixed rods 12b may have a hydrodynamic profile, with a rounded leading edge and a tapered trailing edge, to reduce the drag of the second filter.

Figures 15, 15A, 15B show movable 112a and fixed 14a rods of the third filter 14, according to one embodiment. The fixed rods 14a are spaced apart by a distance L23. The meshes of the filter 14 thus have dimensions L23×W22. The fixed rods 14a can have a circular or hydrodynamic profile.

Figure 16 shows filter 113, according to one embodiment. In the example of Figure 16, the filter 113 is in the form of a square-mesh sieve of width L24. Meshes of the filter 113 can be formed by rods of round or profiled section. Of course, any other mesh shape for the filter 13 may be suitable, such as a honeycomb shape.

According to one embodiment, the ratio between the spacing between the rods or the width of the meshes of each pair of consecutive filters (11, 112), (112, 14), (14, 113) can be between 2.5 and 3.5. According to an exemplary embodiment, the spacing L21 between the rods 11 is between 5 and 8 cm, the spacing W22 between the rods 112a is between 1 and 1.5 cm, the spacing L22 between the rods 12b is between between 2.5 and 3 cm, the spacing L23 between the rods 14a is between 0.7 and 1.3 cm, and the width L24 of the meshes of the filter 113 is between 0.3 and 0.6 cm. The screen filter 14 is therefore of narrower mesh than the filter 112. The additional drag induced by the filter 14 is therefore useful.

Figures 17, 18 represent a filtering device 100, according to one embodiment. The filtering device 100 comprises a tubular duct 120 having an inlet opening 121, an upstream section 120a channeling a flow of fluid to be filtered having penetrated through the inlet opening 121 towards the filters 12, 13 (or 112, 14 , 113), and a downstream section 120b channeling a flow of filtered fluid towards an outlet opening 122 of the conduit. The duct 120 can be arranged to house the filtering device 1 or 10, with the filter 11, formed of parallel rods fixed along two opposite edges of the inlet opening 121. In the example of FIGS. 17 and 18 , the parallel rods forming the filter 11 are curved. The filter 12 (or 112 possibly with the filter 14) can be arranged in an upstream section 120a of the pipe, and the filter 13 (or 113) can be arranged between the upstream section 120a and the downstream section 120b.

The filtering device 100 can be used while being immersed in a flow of fluid 2, for example pulled or pushed under the surface of a body of water, or kept fixed under the surface of a watercourse. It can be observed that only the inlet opening 121 of the device can be submerged, the longitudinal axis X of the device 100 being maintained at an angle of less than 25° with respect to the surface 1 of the water.

According to an embodiment illustrated by FIG. 18, the upstream section 120a delimits an internal volume of tubular shape having a cross section, for example of rectangular shape and of constant surface between the inlet opening 120 and the inlet of the filter 13 or 113. Thus the total surface of each of the filters 12, 13 (or 112, 113 and possibly 14) can be identical to the surface of the inlet opening 121. The downstream section 120b delimits an internal volume of frustoconical shape with an internal section, for example of rectangular shape, narrowing from the outlet of the filter 13 or 113 at the outlet opening 122. The internal volume of the downstream section can have other shapes such as that of a hyperboloid of revolution.

The outer surface of the duct 120 may have, around the inlet opening 121, a curved profile widening from the inlet opening 121. At the junction of the upstream 120a and downstream 120b sections, the profiles of the latter have the same tangent outside the duct. It can be observed that such a profile generates a drag opposite to the direction of flow 2, i.e. favoring the movement of the device in the flow. In the example of FIG. 18, this curved profile widens to about half the length of the upstream section 120a, then narrows to the outlet opening 122. According to one embodiment, the ratio between the length of the inner profile and the length of the outer profile of the upstream section 120a is between 0.7 and 1.0. The bulge thus produced increases the length of the path traveled by the fluid and therefore increases the speed of the latter around the upstream section 120a. This results in a decrease in the pressure around the upstream section 120a, which creates a positive drag. A better hydrodynamic performance of the tubular conduit 120 is thus obtained, regardless of the speed of the fluid in and around the conduit.

According to one embodiment, the upstream section 120a has, in a plane passing through the longitudinal axis X of the duct, a curved or rectilinear internal profile, and forming with the direction of the flow 2 an angle comprised between 0° and 10°, and preferably between 0 and 4°. These features help reduce drag acting in the direction of flow 2.

According to one embodiment, the downstream section 120b has, in a plane passing through the longitudinal axis X of the duct 120, a rectilinear or curved internal profile and forming with the direction of the flow an angle a comprised between 0 and 20°, and preferably between 4 and 9°.

According to one embodiment, the downstream section 120b comprises a section 120c whose downstream end delimits the outlet opening 122. The size of the internal section of the section 120c is such that the edge of the opening 122 is tapered, in order to to avoid the possible detachment of the fluid from the external wall of the conduit 120 in this zone.

According to one embodiment, the surface of the outlet opening 122 is defined so that the speed of the fluid leaving the conduit 120 is between 80 and 110%, and preferably equal to 100% of the speed of the fluid around the outlet opening 122. In this way, the shear appearing at the interface between the fluid exiting through the outlet opening 122 and the fluid outside the conduit is reduced, which makes it possible to reduce the drag s exercising on the conduit 120. The surface of the outlet opening 122 can be adjusted by acting on the length of the downstream section 120b and on the angle a. Furthermore, the speed of the flow in the duct depends on the characteristics of the filters 11, 12, 13 (or 11, 112, 14 and 113), and in particular on the drag coefficients of these filters. The lower these coefficients, the more the length of the downstream pipe 120b can be reduced, which also reduces the overall drag of the pipe 120. Furthermore, the lower the drag coefficients of the filters, the more the speed of the fluid in the pipe can be high. Thus, the exit opening 121 can be widened.

According to one embodiment, the cleaning devices are stored when stationary in the thickness of the wall 120, so as not to obstruct the passage of the flow of fluid 2.

Figures 19, 20 show a filtering system 200 installed in a watercourse. The filtering system comprises a set of several filtering devices 1 or 10 arranged side by side in a checkerboard pattern attached to posts 218 anchored in the bed of the stream. All of the filtering devices can be fixed to the posts 218 in a sliding manner in order to be able to remain at the same distance from the surface of the watercourse thanks to floats 219. A maintenance walkway 216 secured to the set of devices filter 10, and equipped with a guardrail 217, can be provided to access the filter devices 10 from above. be removed from the water for maintenance purposes. Figures 19, 20 show a filter device in the service position 10' above the surface of the watercourse. An electromechanical device can move each of the filtering devices 10 between their functional position in the watercourse and their maintenance position 10'.

The filtering system 200 can also comprise a first filter, for example formed by the set of parallel rods 11 arranged upstream of the set of filter devices 10, the set of parallel rods 11 being associated with the cleaning device 15.

It can be observed that the filtering devices 10 can be arranged in the same plane and be raised above the surface of the watercourse for maintenance, by a translational movement in the direction of the flow 2, then by a movement translation upwards between slides.

Figure 21 shows a filtering system 201 which differs from system 200, in that it is entirely floating and anchored to a fixed point 230 upstream of system 201. Figures 22, 22A, 23, 23A show filtering systems 101, 102, 103, 104, according to other embodiments. In the filtering systems 101-104, several filtering devices 1 or 10 are arranged side by side in a duct such as the duct 120 (FIGS. 17, 18) having an inlet opening 121 with the dimensions of the inlet openings of the filtering devices 1, 10 arranged side by side. The 101-104 filter systems can be attached to the bottom of a stream over 50 feet.

In the example of Figures 22, 22A, three filter devices 1, 10 are arranged horizontally in the system 101. In the example of Figures 23, 23A, two or three filter devices 1, 10 are arranged vertically in the systems filters 102, 103, 104.

It will clearly appear to those skilled in the art that the present invention is capable of various variant embodiments and various applications. In particular, the invention is not limited to a filtering device comprising the first filter 11 and the last filter 13, 113, only the second filter 12a, 12b being sufficient to retain debris entrained by the flow of fluid 2.

It should also be noted that the second set of rods 12a, 112a can be moved in various other ways and does not necessarily form an endless loop. Thus, FIGS. 24 and 25 represent a filtering device 50 according to another embodiment. The filtering device 50 comprises a duct 60, and a filter 52 arranged across the duct 60. The filter 52 is formed by a set of fixed parallel rods 52b, and a set of movable rods 52a, perpendicular to the rods 52b, fixed between them at their ends and held against the rods 12b, for example upstream of the latter. The rods 52a are movable in translation in the direction of the rods 52b, back and forth, between two chambers 75, 75' on either side of the duct 60, where they can be cleaned, for example by plates 85 , 85 'which can have the same structure as the plate 35 and act in the same way as the latter to clean the rods 52a. The chambers 75, 75' can have the width and height of the duct 60 at the level of the filter 52 (figure 24), or else be of smaller width, for example by winding the rods 52a around drums 72, 72' (figure 25). Thus, the rods 52a have a length that can correspond to the height of the duct 60, and all of the rods 52a have a width that can correspond to twice the width of the duct 60. The rods 52b can have an L-shape at their ends. , the rods 52b being fixed together at the end of the L-shapes, in order to allow the debris entrained by the rods 52a to be driven towards the collection chamber 75, 75' without being sheared and without blocking the advancement of the rods 52a towards the collection chambers 75, 75'. Rods 52a may be identical to rods 12a or 112a.

In addition, each of the two sets of rods forming a filter can be movable in the direction of the rods of the other set of rods. Thus, FIG. 26 represents a filtering device 50′ comprising a filter 52′, according to another embodiment. The filter 52' differs from the filter 52 in that the set of rods 52b is also movable in translation in the direction of the rods 52a, back and forth, between two chambers 76, 76' on either side of the duct 60, where they can be cleaned, for example by trays in the form of trays 85, 85'. The chambers 76, 76' can also have the width and height of the duct 60 at the level of the filter 52, or else be of smaller width, for example by winding the rods 52b around drums, the axis of the rods being parallel to that of the drums. Thus, the rods 52b have a length that can correspond to the width of the duct 60, and the set of rods 52b has a height that can correspond to twice the height of the duct 60.

The filter 13, 113 can also be movable back and forth so that it can be cleaned on each side of the duct, for example by suction devices 41' (FIG. 25) arranged on each side of the duct. The filter 13, 113 can thus have twice the width of the duct and be flexible so that it can be rolled up on drums 72'. The filter 113 can include an element such as a slider 113a, for example arranged in the middle position of the filter, to lead the debris towards the suction devices 41'.

In the filter 12, 112, the edge of the movable rods 12a, 112a on the side of the fixed rods 12b is not necessarily straight, but may include notches in which the rods 12b slide. This arrangement can also be implemented in the filter 14 or 52.

Furthermore, in the filter 12, 112, 52, the rods 12b, 52b can be provided sufficiently rigid to be able to be fixed only at one of their ends.

Furthermore, the internal section of the duct 20, 120 can be of any shape, for example circular, elliptical, square, rectangular, trapezoidal, triangular, polygonal or a shape combining these shapes.

It is also not necessary for the rods 12a, 12b forming the filter 12 (or 112, 14, 52) to be perpendicular, the meshes of the filter 12 (or 14, 112, 52) possibly being in the form of a parallelogram.

Claims

1. Filtering device comprising: a main conduit (20, 60) receiving a flow of fluid to be filtered, and a first filter (12, 112, 52) in the form of a sieve comprising a first set of rods (12b, 52b) parallel , arranged across the main duct, and a second set of rods (12a, 112a, 52a) held parallel to each other and arranged across and against the rods of the first set to form the screen meshes, the rods of the second set of rods being movable relative to the rods of the first set of rods, and a drive device (31-33, 72, 72') for moving the rods of the second set of rods at least to a collection chamber (25, 125 , 75) of debris to move debris retained by the first screen-shaped filter to the collection chamber.

2. Device according to claim 1, in which the rods (12a, 112a) of the second set of rods are fixed together in an endless loop stretched between pulleys (31-33).

3. Device according to claim 1 or 2, wherein the collection chamber (25, 125, 75) is located outside the main conduit (20, 60), a cleaning device (35, 135) of the rods of the second set of rods 12a, 112a, 52a) being arranged in the collection chamber.

4. Device according to one of claims 1 to 3, comprising a plate (35, 135, 85, 85 ') provided with a comb (39a, 39b) and movable in the collection chamber between two opposite positions comprising a position discharge pipe (35b) to a debris discharge duct (26) and an opposite position (35a), the tray being held in a deployed position where the comb is inserted between the rods (12a, 112a, 52a) of the second set of rods when the plate is moved towards the evacuation position, and in a retracted position when the plate is moved towards the opposite position, the plate being configured to lead towards the evacuation duct of the debris entrained by the rods of the second set of rods.

5. Device according to claim 4, wherein the plate (35, 135, 85, 85 ') comprises teeth (39b) arranged to slide in a groove (112f) formed in each of the rods (112a) of the second set of rods.

6. Device according to one of claims 1 to 5, wherein each of the rods of at least some of the rods (12a, 112a) of the second set of rods comprises hooks (12c, 112c) arranged along the rod on areas of contact with the rods (12b) of the first set of rods, to drive towards the collection chamber (25), debris wrapped around the rods of the first set of rods, the hooks engaging in a groove (12d , 112d) formed in the rods of the first set of rods.

7. Device according to one of claims 1 to 6, comprising a second filter formed by a third set of parallel rods (14a) fixed across the main conduit (20), and a part downstream with respect to the flow of fluid, rods (112a) of the second set, the rods of the second set being fixed together in an endless loop, the rods (112a) of the downstream part of the rods of the second set being in contact with the rods of the third set of rods, for moving debris retained by the second filter to a collection chamber (125).

8. Device according to claim 7, in which each of the rods (112a) of at least part of the second set of rods comprises hooks (112e, 112g) arranged along the rod on areas of contact with the rods ( 14a) of the third set of rods, to lead to the collection chamber (25, 125), debris wrapped around the rods of the third set of rods.

9. Device according to one of Claims 7 or 8, in which: the rods (12b) of the first set of rods are spaced apart from each other by a distance (L12, L22) greater than or equal to a spacing distance (W12, W22) of the rods (12a, 112a) of the second set of rods, and/or the rods (14a) of the third set of rods are spaced apart from each other by a distance (L23) less than the distance of spacing (W22) of the rods (112a) of the second set of rods.

10. Device according to one of claims 1 to 9, in which: the rods (12b, 52b) of the first set of rods are fixed at one end on the collection chamber side (25) via an L-shape extending downstream in the direction of flow, to allow debris entrained by the stems (12a) of the first set of stems to be drawn into the collection chamber without being sheared and without blocking the advancement of the stems of the second set of rods, or the rods (12b, 52b) of the first set of rods are attached only at one end opposite the collection chamber (25).

11. Device according to one of claims 7 to 10, comprising: a fourth set of parallel rods (11) arranged upstream of the first set of rods (12b), and/or a sieve (13, 113) arranged downstream of the second set of rods (12a, 112a), the mesh width ( L14, L24) of the sieve being less than a spacing distance (W12, L12, W22, L22, L23) of the rods of the second set of rods or of the rods (14a) of the third set of rods.

12. Device according to one of claims 1 to 11, wherein the rods (11, 12a, 12b, 112a, 14a) of at least one of the sets of rods have a tapered cross section.

13. Device according to one of claims 1 to 12, wherein the main conduit (120) comprises: an inlet opening (121) receiving the flow of fluid, an outlet opening (122), a downstream section (120b ) channeling the flow of fluid towards the outlet opening, the outlet opening having a surface smaller than a surface of the inlet opening, the surfaces being considered in a plane perpendicular to a longitudinal axis (X) of the duct main, and an upstream section (120a) channeling the flow of fluid to be filtered having entered the main duct towards the first and second sets of rods (12a, 112a, 12b), and in which: the upstream section (120a) present in a plane passing through the longitudinal axis (X) of the main duct an internal profile forming with the direction of the flow or the longitudinal axis of the main duct an angle of zero or between 0 and 16°, and/or the downstream section (120b ) has, in a plane passing through the longitudinal axis (X) of the main conduit, a straight or curved internal profile and forming with the direction of the flow an angle between 0 and 20, and preferably between 4 and 9°, and/ or the surface of the outlet opening (122) is adjusted so that the speed of the fluid flow leaving the main conduit is between 80 and 110% of the speed of the fluid around the outlet opening, and/or the surface area of the exit opening (122) is between 0.1 and 5 times the total surface area for fluid to pass through the first and second sets of rods (12b, 12a, 112a), and/or the upstream section of the duct (20, 120) has a bulge on its outer face.

14. Device according to one of claims 1 to 13, wherein the main duct (20, 120, 60) has a section of circular, elliptical, trapezoidal, triangular, polygonal, square or rectangular shape, or a shape composed of these forms.

15. Filtering system comprising a plurality of filtering devices (1, 10) according to one of claims 1 to 14, fixed side by side across a flow of fluid.

16. Filtering system according to claim 15, in which the filtering devices (1, 10) are arranged in a primary duct (120) comprising: an inlet opening (121) receiving the flow of fluid, an outlet opening (122), a downstream section (120b) channeling the flow of fluid towards the outlet opening, the outlet opening having a surface smaller than a surface of the inlet opening, the surfaces being considered in a perpendicular plane to a longitudinal axis (X) of the primary duct, and in which: the upstream section (120a) has, in a plane passing through the longitudinal axis (X) of the primary duct, an internal profile forming with the direction of the flow or the axis longitudinal axis of the primary duct at an angle of zero or between 0 and 16°, and/or the downstream section (120b) has, in a plane passing through the longitudinal axis (X) of the primary duct, a rectilinear or curved internal profile and forming with the direction of the flow an angle between 0 and 20, and preferably between 4 and 9°, and/or the surface of the outlet opening (122) is adjusted so that the speed of the fluid flow at the outlet of the primary duct is between 80 and 110% of the fluid velocity around the outlet opening, and/or the area of the outlet opening (122) is between 0.1 and 5 times the total area of passage of the fluid through the first and second sets of rods (12b, 12a, 112a), and/or the upstream section of the primary duct has a bulge on its outer face.