Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02B—HYDRAULIC ENGINEERING
  • E02B15/00—Cleaning or keeping clear the surface of open water; Apparatus therefor
  • E02B15/04—Devices for cleaning or keeping clear the surface of open water from oil or like floating materials by separating or removing these materials
  • E02B15/10—Devices for removing the material from the surface
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02B—HYDRAULIC ENGINEERING
  • E02B15/00—Cleaning or keeping clear the surface of open water; Apparatus therefor
  • E02B15/04—Devices for cleaning or keeping clear the surface of open water from oil or like floating materials by separating or removing these materials
  • E02B15/048—Oil collectors moved over the water skimming the water surface

Definitions

• Devices capable of being towed by ships have also been proposed. Such a device is, for example, described in patent EP 2812498.
• This device comprises a channel arranged on the surface of the body of water in the direction of movement of the ship.
• the channel has a width increasing from the entrance of the channel to the entrance of a filter, in an attempt to reduce the drag of the filter and therefore limit the excess energy consumption of the ship due to the presence of the device dragged on the surface of the body of water.
• This device has the disadvantage of only being usable at low speed, less than 2 m/s, in particular to retain its ability to guide the fluid entering the filter. It is unsuitable for equipping ships generally moving at more than 2 m/s.
• the channel arranged around the filter introduces a drag which may be greater than that of the filter.
• Embodiments relate to a filtering device comprising: a conduit provided to be immersed in a flow of fluid, and a filter disposed in the conduit to filter the fluid entering the conduit, the conduit comprising: an inlet opening receiving the flow of fluid, an upstream section extending from the inlet opening and housing the filter, an outlet opening, and a downstream section extending from the filter to the outlet opening, to channel the flow of fluid leaving the filter towards the outlet opening, the downstream section having a length greater than or equal to the length of the upstream section, the outlet opening having a surface area smaller than a surface of the inlet opening, the surfaces being considered in a plane perpendicular to a longitudinal axis of the duct.
• the upstream section has, in a plane passing through the longitudinal axis of the duct, an internal profile forming with the direction of the flow an angle of zero or between 0 and 16° towards the longitudinal axis of the duct.
• the duct has a bulge on its outer face around the inlet opening, the bulge having at the inlet opening a tangent forming an angle greater than 45° with respect to the longitudinal axis of the duct.
• the downstream section has, in a plane passing through the longitudinal axis of the conduit, a rectilinear or curved internal profile and forming with the direction of the flow an angle comprised between 0 and 20, and preferably comprised between 4 and 9 °.
• the device comprises a grid arranged in front of the filter and having a passage surface for the fluid flow greater than the passage surface of the filter, the grid being placed in the duct, or else in front of the opening of the duct to perform a filter and/or breakwater function, the grid being associated or not with a cleaning or suction device to evacuate the debris retained by the grid.
• the device comprises at least one filter having one of the following characteristics: the filter has a conical or pyramidal shape, the filter has a conical or pyramidal shape and a debris evacuation opening at the top of the conical or pyramidal shape, the filter is flat and arranged perpendicular to the longitudinal axis of the conduit, the filter is flat and inclined relative to the longitudinal axis of the conduit, the filter has a plurality of juxtaposed grooves with a cross-section in the shape of V, each face of the filter has a convex part and a concave part, the filter is formed of parallel rods, and the filter has profiled rods or meshes in order to reduce the drag of the filter.
• the filter is associated with a cleaning device or a suction device, to evacuate debris retained by the filter.
• the method comprises a step of collecting debris in a reservoir.
• the flow of water has a speed of between 1 and 15 m/s.
• Figure 1 shows in longitudinal section along a vertical plane, a filtering device according to one embodiment
• FIG. 2 is a perspective view of a filtering device, according to another embodiment
• Figure 4 is a longitudinal sectional view of a filter of the filtering device, according to one embodiment, and Figure 4A is a detailed sectional view of part of the filter shown in Figure 4,
• Figure 5 is a perspective view of the filtering device, according to another embodiment.
• Figure 6 is a longitudinal sectional view along a vertical plane of the filter device of Figure 5, according to one embodiment
• FIG. 7 is a view in longitudinal section along a vertical plane of the filtering device, according to another embodiment
• Figure 8 is a perspective view of the filtering device, according to another embodiment
• FIGS. 9A, 9B are views in longitudinal section along a vertical plane and along a horizontal plane of the filtering device of FIG. 8, according to one embodiment,
• FIG. 10 is a perspective view of a filter of the filtering device, according to another embodiment,
• FIGS. 11 A and 11 B are views from above and in longitudinal section, respectively in a horizontal plane and in a vertical plane, of a filtering device, according to another embodiment,
• FIG. 12 [Fig. 13]
• Figures 12 to 14 are views in longitudinal section along a vertical plane of filtering devices, according to various other embodiments,
• FIG. 15 [Fig. 16] Figures 15 and 16 are views in longitudinal section along a vertical plane of filtering devices, according to the prior art.
• FIG. 1 represents a filtering device 10 according to one embodiment.
• the device 10 comprises a filter 14 disposed in a tubular conduit 11 comprising an upstream section 11a channeling a flow of fluid to be filtered having entered through an inlet opening 12 of the conduit, and a downstream section 11b channeling a flow of filtered fluid towards a outlet opening 13 of the duct.
• the filter 14 is arranged in the conduit between the upstream and downstream sections, so as to receive the flow of fluid to be filtered.
• the filtering device 10 can be used by being immersed in a flow of fluid, for example pulled or pushed under the surface 1 of a body of water, or kept fixed under the surface of a watercourse. It can be observed that only the inlet opening 12 of the device can be submerged, the longitudinal axis X of the device 10 being maintained at an angle of less than 25° with respect to the surface 1 of the water.
• the upstream section 11a delimits an internal volume of cylindrical shape having a constant surface section between the inlet opening 12 and the inlet of the filter 14.
• the downstream section 11b delimits an internal volume of frustoconical shape with an internal section narrowing from the outlet of the filter 14 to the outlet opening 13.
• the internal volume of the downstream section may have other shapes such as that of a hyperboloid of revolution.
• the ratio between the length of the inner profile and the length of the outer profile of the upstream section 11a 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 11a. This results in a decrease in the pressure around the upstream section 11a, which creates a positive drag. A better hydrodynamic performance of the tubular conduit 11 is thus obtained, regardless of the speed of the fluid in and around the conduit.
• the upstream section 11 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 an angle comprised between 0° and 16°, and preferably between 4 and 9°. These features help reduce drag acting in the direction of flow 2.
• the downstream section 11b has, in a plane passing through the longitudinal axis X of the duct 11, a rectilinear or curved internal profile and forming with the direction of the flow an angle a of between 0 and 20°.
• the downstream section 11b comprises a section 11c having a circular internal section, the downstream end of which delimits the opening 13.
• the size of the internal section of the section 11c is such that the edge of the opening 13 is tapered.
• the transition zone between the frustoconical internal part and the cylindrical internal part 11c of the downstream section 11b may have a rounded external profile, in order to delay the possible detachment of the fluid from the external wall of the conduit 11 in this zone.
• the surface of the outlet opening 13 is defined so that the speed of the fluid leaving the conduit 11 is between 80 and 110%, and preferably equal to 100% of the speed of the fluid around the outlet opening 13. In this way, the shear appearing at the interface between the fluid leaving through the outlet opening 13 and the fluid outside the duct is reduced, which makes it possible to reduce the drag s exerting on the conduit 11 .
• the surface of the outlet opening 13 can be adjusted by acting on the length of the downstream section 11b and on the angle a. Furthermore, the flow velocity in the duct depends on the characteristics of the filter and in particular its drag coefficient. The lower this coefficient, the more the length of the downstream duct 11b can be reduced, which also reduces the drag of the downstream duct. Furthermore, the lower the drag coefficient of the filter, the higher the fluid velocity through the filter can be. Thus, the outlet opening 13 can be larger.
• Filter 14 includes pores or mesh through which fluid can flow.
• the “passage area” of the filter designates the sum of the surfaces of the pores or meshes of the filter.
• the outlet opening 13 has a lower surface than the passage surface of the filter 14, in order to reduce the difference between the speed of the fluid at the outlet 13 of the conduit 11 and the speed of the fluid around the conduit outlet.
• Outlet opening 13 may have a surface area of between 0.1 times and five times the fluid passage surface through filter 14, depending on the characteristics of the filter.
• the meshes of the filter can be delimited by a wire of circular section.
• the wire delimiting the meshes of the filter has a hydrodynamic profile (lower drag coefficient) oriented in the direction of the flow of fluid 2, as illustrated by FIG. 4A.
• the filtering device 10 comprises a grid 17 (or several) arranged in front of the filter 14 to prevent excessively large debris from entering the conduit 11 as far as the filter, and to channel them towards a tank 22 for storing these debris which can be fixed above the pipe 11.
• the grid 17 comprises parallel rods inclined at the top towards the rear of the pipe 11 as far as an inlet of the tank 22 so that the debris can be drawn towards the reservoir 22 under the effect of the flow of fluid 2.
• the conduit 11 has an upper opening 26 through which the rods of the grid 17 pass.
• the grid 17 may have a flow passage surface of fluid greater than the passage surface of the filter 14.
• the rods forming the grid 17 have a hydrodynamic profile in order to minimize their drag under the effect of the flow of fluid 2.
• a profiled element 27 provided to perform the function of breakwater and deflector to repel very large debris, is held in front of the inlet opening 12 by rods 23.
• the profiled element 27 can present a hydrodynamic profile in order to limit its drag
• the filter 14 has a conical shape whose axis substantially coincides with the axis X of the conduit 11.
• the filter 14 has an opening at the top of its conical shape, arranged in downstream in the conduit 11 and opening into a conduit 24. The shape of the filter 14 makes it possible to channel the debris collected towards the conduit 24 under the effect of the flow of fluid passing through the filter.
• the inlet opening 12 is centered on the longitudinal axis of the conduit 11.
• the conduit 11 has a symmetry of revolution around its longitudinal axis X (disregarding the opening 26).
• each angular sector (around the longitudinal axis X of the duct) of the duct 11 tends to exert a pushed out of the conduit in a direction perpendicular to the inner surface of the conduit.
• the thrusts exerted by the different sectors of the conduit are balanced.
• this balance disappears because the upper sector of the duct no longer exerts upward thrust.
• the lower sector of the duct tends to drag the duct 11 downwards, in a position of complete immersion.
• This effect can also be obtained using fins fixed to the external face of the duct, on the top, at the front or at the rear of the duct, or on each side of the duct 11 (fins 19 in the figure 2), so as to remain submerged, and oriented so as to exert an upward thrust less than or equal to the downward thrust exerted by the conduit when it is only partially immersed.
• FIG. 4 shows the filter 14 according to one embodiment.
• the filter 14, of conical shape is associated with a cleaning device 15 comprising a brush configured to brush the meshes of the filter 14, and to turn on itself and around the longitudinal axis of the filter 14, the debris being driven towards the top of the conical shape to be evacuated through conduit 24, under the effect of the fluid flow.
• the rotational drive of the brush can exploit the pushing force of the fluid flow passing through the filter.
• the cleaning device is fixed and the filter 14 rotates around its longitudinal axis. Evacuation of debris to conduit 24 can be effected or facilitated by the application of vibrations to the filter.
• FIG. 5 show a filter device 30 according to another embodiment.
• the filtering device 30 differs from that of FIG. 2 in that it comprises a duct 31 of rectangular section with inlet 32 and outlet 33 openings of rectangular shape.
• the filter 14 is replaced by a filter 34.
• the filter 34 can be associated with a cleaning device 35 in the form of a roller brush which moves between the lower and upper parts of the filter 34 to sweep debris onto the filter to a 21' tank.
• the filtering device 30 can also comprise a set of parallel rods 37, fixed in the duct 31 between the inlet opening 32 and the filter 34. The rods 37 make it possible to evacuate the large debris towards a tank 22 ′ arranged at the above conduit 31 .
• each of the rods 37 has an inclined part in front of the opening 32 of the duct 31, so that the upper part of the rod is further downstream with respect to the duct 31 than a lower part of the inclined part of the stem.
• the debris retained by the rods 37 can be pushed upwards into the reservoir 22' under the effect of the flow of fluid.
• the duct 31 has an upper opening 26' through which the rods 37 pass.
• the rods 37 may have a passage surface for the flow of fluid greater than the passage surface of the filter.
• the rods 37 can for example have a fluid flow passage surface greater than 70% of the surface of the cross section of the duct.
• the rods 37 are profiled in order to minimize their drag under the effect of the flow of fluid 2.
• the rods 37 are also associated with a cleaning device 36 moving along the rods to carry the debris towards the tank 22'.
• the duct 31 is associated with lateral fins 39 arranged to keep the duct 31 submerged just below the surface 1 of the fluid, as illustrated in FIG. 5. Fins can also be placed on top, in front, behind or below conduit 31.
• the filter 44 is flat and arranged in the duct 41 like the filter 34 in the duct 31, in an inclined position towards an opening provided in an upper part of the duct 41, or in a space provided between the faces external and internal of the conduit 31.
• the filter 44 can also have the form of the filter 14 coupled to a conduit for the evacuation of the debris towards a reservoir.
• the conduit 31' and in particular the upper external face of the conduit is shaped so as to house all the rods 37 and the reservoirs 21", 22".
• the upper outer face of the duct may for example have an extended bulge for this purpose.
• the opening 26 is not necessary and can be omitted.
• FIG. 8 shows a filter device 40 according to another embodiment.
• the filtering device 40 differs from that of FIG. 2 in that it comprises a duct 41 of rectangular section with inlet 42 and outlet 43 openings of rectangular shape.
• the filter 14 is replaced by a filter 44.
• the filter 44 can be associated with a cleaning device 45 in the form of a roller brush moving between the lower and upper parts of the filter 44.
• the filtering device 40 can also comprise a set of parallel rods 47, fixed to the outside of the duct 41 opposite the inlet opening 42.
• the rods 47 act as a breakwater and allow large debris to be evacuated. to a tank 48 arranged above the conduit 41.
• each of the rods 47 has a portion inclined in front of the opening 42 of the conduit 41, so that the upper part of the rod is further downstream with respect to the conduit 41 than a lower part of the inclined part of the rod.
• the lower part of the inclined part of the rods is connected to a lower part of the edge of the opening 42 by a part directed towards the downstream, slightly inclined with respect to the horizontal.
• the rods 47 have a hydrodynamic profile oriented in the direction of the flow 2 of fluid.
• the duct 41 is associated with lateral fins 49 arranged as illustrated in FIGS. 8, 9B, to keep the duct 41 submerged just below the surface 1 of the fluid.
• Figure 10 shows a filter 44' according to another embodiment.
• the filter 44' has a plurality of juxtaposed grooves with a V-shaped cross section.
• the filter 44' can be arranged in the conduit 41 so that its grooves are oriented in a vertical longitudinal plane of the conduit and inclined at the top the rear of the duct 44.
• the filter 44' can be associated with a cleaning brush arranged horizontally and having a shape matching the shape of the section of the filter in a horizontal plane. The cleaning of the 44' filter can be carried out by moving the brush between the lower and upper parts of the 44' filter.
• the filter has a pyramidal shape with a square or rectangular section, with a pointed or straight apex.
• the filter in order to be able to be adapted to the filtering device 40, can be pyramidal in shape with a rectangular section and apex in the form of a straight segment.
• the cleaning of the filter is carried out by a suction system coupled to a reservoir (for example 21, 21' or 48), and comprising a pump connected to a pipe whose end is moved along the filter surface.
• a suction system coupled to a reservoir (for example 21, 21' or 48), and comprising a pump connected to a pipe whose end is moved along the filter surface.
• the tank receiving the debris can also be connected by a pipe to a larger tank.
• FIGS. 8, 9A and 9B represent a filtering device according to another embodiment.
• the filtering device comprises the conduit 41 described with reference to FIGS. 8, 9A and 9B, and a set of parallel rods 47' held in front of the upstream opening of conduit 41 by two floats 9, conduit 41 being secured to floats 9, for example by cables 8.
• rods 47' make it possible to evacuate the large debris towards a tank 48' fixed above the floats 9.
• the rods 47' are inclined in front of the opening 42 of the conduit 41, so that the upper part of the rods either further downstream with respect to conduit 41 than a lower part of the rods.
• the debris retained by the rods 47' can be pushed upwards into the reservoir 48' under the effect of the flow 2 of fluid.
• the rods 47' are associated with a cleaning device moving along the rods to carry the debris towards the tank 48'.
• the filter can also be cleaned using a pressure pump emitting a jet of water opposite to the flow direction 2 of the fluid.
• the floats 9 are replaced by one or more fins connected to the grid formed by the rods 47' in order to provide lift and to maintain the grid at the desired height, with a submerged part and an emerged part. .
• FIG. 13 represents a filtering device 60 comprising a pipe 61 and a filter 64.
• the pipe 61 only comprises a downstream section 61b.
• the interior volume of the downstream section 61b has, in the horizontal longitudinal plane, a trapezoidal section symmetrical with respect to the longitudinal axis X, and widening upstream as far as the filter 64 from the angle a2 with respect to the longitudinal axis X.
• the outer shape of the longitudinal section of the downstream section 61b widens following a rounded contour, then becomes substantially rectilinear.
• the outlet opening 63 has a surface smaller than the surface of the inlet opening 62 corresponding to the size of the filter 64.
• the inlet opening 62 may have the bulge described
• FIG. 15 represents a filtering device 80 comprising a conduit 81 and a filter 84.
• the conduit 81 comprises only an upstream section 81a.
• the interior volume of the upstream section 81a has, in the horizontal longitudinal plane, a trapezoidal section symmetrical with respect to the longitudinal axis X, and widening downstream to the filter 84 of the angle a1.
• the longitudinal section of the upstream section 81 has a rounded shape, tapered at the inlet 82 and outlet 83 openings, and thicker between the openings 82, 83.
• the outlet opening 83 corresponding to the size of the filter 84 has a surface greater than the surface of the inlet opening 82.
• the drag of the filter device when it is dragged through the water, for example by a ship.
• the drag results from four additive components, namely the filter pressure drag and viscous drag, and the duct pressure drag and viscous drag.
• drag is related to the velocity of the fluid along the walls of the conduit and through the filter.
• Filter pressure drag is related to the shape of the filter, the aggregate filter mesh area and the cross-sectional area of the filter.
• the viscous drag of the filter is caused by the friction of the water on the walls formed by the meshes of the filter. It is therefore low because the friction surface is low.
• the viscous drag of the pipe depends on the friction surface of the fluid on the inner and outer walls of the pipe.
• the pressure drag depends on the shape and cross-sectional area of the duct.
• Various simulations were carried out to evaluate the performance of the various profiles presented with reference to figures 1 and 12 to 16, by fixing the speed of the fluid around the pipe at 11 m/s, i.e. 21.38 knots, and by fixing the cumulative surface meshes of the filter to 50% of the total surface of the filter, these surfaces being considered in a transverse plane.
• Table 1 below were obtained with a flat filter placed in the circular section duct, in an inclined position, the upstream face of the filter being oriented upwards.
• the results collated in Table 2 below were obtained with a flat filter placed perpendicular to the longitudinal axis X of the duct.
• the first column of tables 1 and 2 contains the references of the filtering devices as used in FIGS. 1 and 12 to 16.
• Columns 2 and 3 of tables 1 and 2 bring together the pressure and viscous drag values of the filter.
• Columns 4 and 5 of tables 1 and 2 bring together the pressure and viscous drag values of the duct.
• Column 6 contains the sum of the drag values indicated in the columns 2 to 5. It should be noted that the negative drag values correspond to a force contributing to the advancement of the device in the fluid, and are obtained thanks to the bulge formed by the outer surface of the upstream section of the duct.
• Column 7 gathers the fluid flow rate values at the conduit outlet.
• the last column indicates the values of the airflow to total drag ratio allowing the efficiency of the different profiles to be compared.
• the present invention is capable of various variant embodiments and various applications.
• the invention is not limited to a device towed or pushed by a ship.
• the device can be fixed relative to a structure channeling the flow of fluid, for example fixed to a fixed structure holding the device in a watercourse.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Mechanical Engineering (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Filtration Of Liquid (AREA)
• Branch Pipes, Bends, And The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2021
  • 2021-02-10 FR FR2101255A patent/FR3119627B1/fr active Active
• 2022
  • 2022-02-10 US US18/276,445 patent/US20240093452A1/en active Pending
  • 2022-02-10 CN CN202280014209.6A patent/CN116888326A/zh active Pending
  • 2022-02-10 WO PCT/FR2022/050244 patent/WO2022171962A1/fr active Application Filing
  • 2022-02-10 EP EP22708203.9A patent/EP4291723A1/de active Pending

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