AU2018376937B2

AU2018376937B2 - Immersed device for swimming pool filtration

Info

Publication number: AU2018376937B2
Application number: AU2018376937A
Authority: AU
Inventors: Serge Bonnefoy; Marc Dejey; Jean-Louis Desjoyaux
Original assignee: Piscines Desjoyaux SA
Current assignee: Piscines Desjoyaux SA
Priority date: 2017-11-30
Filing date: 2018-11-29
Publication date: 2022-12-01
Anticipated expiration: 2038-11-29
Also published as: RU2020120658A; CA3086663A1; AU2018376937A1; FR3074057A1; PL3717094T3; RU2020120658A3; EP3717094B1; RU2770111C2; PT3717094T; FR3074057B1; CN111542381B; MA51215A; EP3717094A1; CN111542381A; WO2019106307A1; ES2900537T3

Abstract

The invention concerns an immersed device (100) for filtering the water of a pool, comprising a filtration bowl (10), which has a first end (11) for receiving the water to be filtered from the pool and a second end intended to be connected to a first filtered-water outlet duct. The device also comprises: • a valve module (30), rigidly attached to the first end (11) of the filtration bowl (10), in order to block the return of water through the first end (11) during a backwashing of the filtration bowl (10); • a drainage duct (40), communicating with the filtration bottle (10), in order to evacuate the water from the filtration bowl (10) during the backwashing.

Description

W O 20 19/106307 A l1|||||||||||||||||||||11111|i|||||||I||| III|| | | | | i|l| | | | | | HiI| ID| | |Il| ZM, ZW), eurasien (AM, AZ, BY, KG, KZ, RU, TJ, TM), europden (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, KM, ML, MR, NE, SN, TD, TG).

Publi6e: - avec rapportde recherche internationale(Art. 21(3)) - avant expiration dudai prevu pour la modification des revendications, sera republiee si des modifications sont revues (regle 48.2(h))

IMMERSED DEVICE FOR SWIMMING POOL FILTRATION FIELD OF THE INVENTION

The present invention relates to the field of filtration systems for pools and swimming pools. Said invention relates in particular to an immersed filtration device compatible with backwashing.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

There are many types of non-immersed filtration devices for pools and swimming pools. By way of example, the filtration unit described in US20160002941 can be cited. Said filtration unit has a plurality of sand filter modules and a function for cleaning the filters by means of reversely flowing water. Systems for filtering swimming pool water that comprise an immersed filtration device appear more advantageous because said systems are more compact and limit the amount of water piping. An immersed device of this kind typically comprises a filter, for example made of fabric, immersed in the water of the pool, and a pump that causes the water to flow, by suction, into the filter, and discharges said water into the pool after filtration. When the filter is clogged, it is removed from the pool and cleaned, for example with a jet of water.

It would be desirable for there to be an immersed filtration device that does not require this removal and cleaning step. As mentioned previously, there are known means for cleaning non-immersed filtration devices (stainless-steel filter, sand filter), which involve causing water to flow reversely, so as to remove from the filter any particles that may have become stuck. However, these techniques are not directly applicable to immersed filtration devices because this would lead to the particles removed from the filter being thrown back into the pool water.

OBJECT OF THE INVENTION

The present invention aims to remedy some or all of the above mentioned drawbacks. The invention relates to an immersed device for filtering the water of a pool, said device being compatible with cleaning by means of reversely flowing water (backwashing). The invention also relates to a filtration system comprising said immersed device.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to an immersed device for filtering the water of a pool, comprising a filtration bowl, which has a first end for receiving water to be filtered from the pool and a second end for being connected to a first outlet duct for filtered water. The immersed filtration device comprises: Sa valve module that is rigidly attached to the first end of the filtration bowl in order to block the backflow of water through the first end during backwashing of the filtration bowl; Sa drainage duct that is in communication with the filtration bowl in order to drain away water from the filtration bowl during backwashing.

According to other advantageous, non-limiting features of the invention, in isolation or in any technically feasible combination: • the filtration bowl is cylindrical; • the valve module comprises a valve that is movable along a shaft parallel to the axis of the filtration bowl in order to open or close a valve opening, the diameter of said valve opening being between 50% and 90% of the diameter of the cross section of the filtration bowl; • the valve module has a valve opening that is offset from the first end towards the inside of the filtration bowl; • the drainage duct is located in an area between the first end and the valve opening;

• the drainage duct comprises a depriming valve; • the filtration bowl is a sand filter and comprises a sand column below the valve module and a bottom filter that is rigidly attached to the second end of said filtration bowl; • the filtration bowl comprises a mesh basket between the valve module and the sand column; • the filtration bowl comprises a sand column or a column of any other solid or fibrous substances capable of filtering; • the bottom filter is cylindrical and is composed of stainless-steel or plastic wires; • the wires have a thickness of 4 mm, are triangular in profile and are spaced less than 500 microns apart; • the immersed filtration device comprises a grate basket that is placed on the valve module in order to filter the water of coarse matter; • the immersed filtration device comprises a multi-hole valve that has a plurality of openings and is placed between the bottom filter and the first outlet duct, said valve being configured to be open when the filtration device is in a filtration mode and to be closed when the device is in a backwashing mode; • the immersed filtration device comprises a pressure relief valve that is placed in a bypass on the first outlet duct in order to bypass the filtration bowl; • the immersed filtration device comprises a rod system in order to manually actuate the pressure relief valve.

The present invention also relates to a filtration system for a pool, comprising: • an immersed filtration device as above, • a pumping device comprising a pump, the first outlet duct for filtered water, and a second duct for discharging the filtered water into the pool; the pumping device being able to cause water to flow selectively, according to a filtration flow, from the first duct to the second duct, or according to a reverse flow, from the second duct to the first duct, for backwashing the filtration bowl.

According to other advantageous, non-limiting features of the invention, in isolation or in any technically feasible combination: • the pumping device comprises a five-port valve that allows the selective flow of water according to a filtration flow or according to a reverse flow; • the pumping device comprises two three-port valves that allow the selective flow of water according to a filtration flow or according to a reverse flow; • the pump comprises a variable-speed drive; • the pump comprises a brushless motor; • the filtration system comprises two safety valves that are respectively positioned on two branches that communicate with the second discharge duct: • the first safety valve being configured to open when water is flowing according to a filtration flow, the second safety valve being closed, • the second safety valve being configured to open when water is flowing according to a reverse flow, the first safety valve being closed.

BRIEF DESCRIPTION OF DRAWINGS

Other features and advantages of the invention will be apparent from the following detailed description, with reference to the accompanying drawings, in which: - Fig. 1a and 1b show examples of immersed filtration devices according to the invention; - Fig. 2 shows a part of an immersed filtration device according to the invention; - Fig. 3 is a sectional view of a valve module for an immersed filtration device according to the invention; - Fig. 4a and 4b show elements of a filtration bowl for an immersed filtration device according to the invention; - Fig. 5(a) and (b) show elements of a drainage duct for an immersed filtration device according to the invention;

- Fig. 6 shows a filtration system according to a first embodiment of the invention; - Fig. 7 shows a filtration system according to a second embodiment of the invention; - Fig. 8a to 8d show a pressure relief valve for an immersed filtration device according to the invention; - Fig. 9a and 9b show a multi-hole valve for an immersed filtration device according to the invention; - Fig. 10 shows two automatic valves included in the filtration system according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the descriptive part, the same reference numerals in the drawings may be used for elements of the same kind. In addition, the drawings are schematic representations which, for the purpose of clarity, are not necessarily to scale.

The invention relates to a device 100 immersed in the water of a pool 200 (or swimming pool), which is used for filtering the water in said pool 200.

The filtration device 100 comprises a filtration bowl 10, preferably cylindrical (Fig. 1a and 1b).

In the context of the invention, the immersed filtration device 100 is configured to directly receive water to be filtered EAF from the pool 200 at a first end 11 of the filtration bowl 10; in practice, said first end 11 leads into a compartment 90 that is filled with water from the pool via a mouth 21, without any intermediate piping (Fig. 1b). The absence of piping between the inlet (first end 11) of the filtration device 100 and the pool water avoids pressure losses in the filtration system. At a second end 12 of the filtration bowl 10, the immersed device 100 is connected to an outlet duct 22 (referred to as the first outlet duct 22) for filtered water EF. It will later be seen how the first outlet duct 22 is in fluid communication with a second discharge duct 60 connected to a discharge nozzle 70 that is immersed in the water of the pool 200 and intended to discharge the filtered water EF into the pool 200.

The filtration bowl 10 has, inside the advantageously cylindrical walls thereof and between the first end 11 and second end 12 thereof, a filter 1, such as a sand filter; of course, the filter 1 may alternatively consist of a diatomaceous earth filter, a fiber filter, a plastic honeycomb pellet filter or any other type of filter.

According to a first embodiment, the filtration bowl 10 comprises a mesh basket 13 near the first end 11 of said filtration bowl, a sand column 1 (or a column of any other solid or fibrous substances capable of filtering) and a bottom filter 14 that is rigidly attached to the second end 12 of said filtration bowl. The mesh basket 13 and the bottom filter 14 allow the sand column to be held in the filtration bowl 10, preventing the grains of sand from being dragged away by the flow of water.

Advantageously, the mesh basket 13 (Fig. 4a) is cylindrical and acts as a mesh, preventing the sand from reaching an area above the mesh basket 13, towards the first end 11 of the filtration bowl 10. The size of the mesh of said basket 13 is, for example, 550 microns.

According to a second embodiment, the filtration bowl 10 comprises a sand column 1 (or a column of any other solid or fibrous substances capable of filtering) and a bottom filter 14 that is rigidly attached to the second end 12 of said filtration bowl, without a mesh basket 13 near the first end 11 of said filtration bowl. The mesh basket 13, which prevents the grains of sand from being dragged away by the flow of water during the backwashing of the filtration device 100, in the first above-mentioned embodiment, is not essential if the water pressure used during backwashing is adapted so as not to disperse and lift the sand column of the filtration bowl 10 (this point will be discussed later on).

Advantageously, for both of the above-mentioned embodiments, the bottom filter 14 is cylindrical and acts as a mesh, preventing the sand from reaching an area below the bottom filter 14, towards the second end 12 of the filtration bowl 10. Said bottom filter is composed of stainless-steel or plastic wires (Fig. 4b), as may also be the mesh basket 13. The wires have a thickness of 4 mm, a triangular profile and are spaced less than 500 microns apart. The opening 14a in the bottom filter 14 communicates with the first outlet duct 22 for filtered water EF; a flange 14b of the bottom filter 14, which is placed around the opening 14a, is sealingly attached to the second end 12 of the filtration bowl 10.

The immersed filtration device 100 also comprises a valve module 30 that is rigidly attached to the first end 11 of the filtration bowl 10. In the example shown in Fig. 1b, the valve module 30 is located above the mesh basket 13. The valve module 30 is configured to allow water to flow from the first end 11 of the filtration bowl 10 (inlet for water to be filtered EAF) to the second end 12 (outlet for filtered water EF) thereof, i.e. to flow according to a filtration flow. Moreover, the valve module 30 is configured to block the backflow of water through the first end 11 in two situations: • in the absence of a flow of water, • or when water is flowing from the second end 12 to the first end 11, i.e. according to a "reverse flow" (in the opposite direction to the filtration flow, in backwashing mode). The reverse flow of water allows the filtration bowl 10 to be cleaned by backwashing, by driving away particles clogging the bottom filter 14 and the sand towards the mesh basket 13 (when present) and/or towards the valve module 30. Since the mesh of the mesh basket 13 is wider than that of the bottom filter 14, said mesh allows said particles to pass through. However, the mesh basket 13 can block some particles or filaments and gradually become clogged. For this reason, a filtration bowl 10 without a mesh basket 13 may sometimes be advantageous (second above-mentioned embodiment).

Advantageously, the valve 32 is movable along a shaft 33 parallel to the axis of the filtration bowl 10 and opens or closes the valve opening 31 depending on the flow of water (Fig. 2 and 3). The diameter of the valve opening 31 may be between 50% and 90% of the diameter of the cross section of the filtration bowl 10. In the reverse flow configuration, the valve 32 of the valve module 30 closes the opening 31 due to the presence of a spring 34. In the example shown in Fig. 3, said spring is located on the shaft 33, rests against the underside of the valve 32, and allows the closed position of the valve 32 (opening 31 closed) to be maintained when water is not flowing according to the filtration flow (i.e. in non-flowing or reverse flow situations). Seals 35 are advantageously provided at the connection between the valve 32 and the shaft 33 and at the connection between the valve 32 and the circumference of the opening 31 in order to seal the valve module 30 in the closed position. When water is flowing according to the filtration flow (i.e. the water is sucked in by the first outlet duct 22), the negative pressure of the water on the valve 32 opens the opening 31 and thus allows water to be filtered EAF to flow from the first end 11 through the filtration bowl 10.

The filtration device 100 also comprises a drainage duct 40 that is in communication with the filtration bowl 10. The function thereof is to drain away, to the sewer, particle-laden water (backwashing water) that flows reversely through the mesh basket 13 (when present) and/or reaches the vicinity of the valve module 30. The drainage duct 40 is located close to the valve module 30, between said valve module and the mesh basket 13 (when present). As shown in Fig. 2, the valve opening 31 of the valve module 30 is advantageously offset from the first end 11 towards the inside of the filtration bowl 10 along the axis of rotation of said bowl 10. The drainage duct 40 is preferably in communication with the bowl 10 in an area between the first end 11 and the valve opening 31 (Fig. 2). When backwashing, since the valve opening 31 is closed (reverse flow of water), the backwashing water is drained away by the drainage duct 40.

The drainage duct 40 preferably comprises a depriming valve 41 (Fig. 5(a) and 5(b)). When backwashing the immersed device 100, the washing water pressure in the drainage duct 40 pushes the depriming valve 41 which, by means of the seal thereof, closes an opening 42; the washing water then continues to flow in the drainage duct 40 towards the sewer. When backwashing is stopped, the water pressure drops and the depriming valve 41 opens, allowing air to pass through and thus depriming the siphon (drainage duct 40); this prevents water from continuing to flow through the drainage duct 40 after the reverse flow has stopped.

In some pool configurations, the drainage duct 40 may be directly connected to an overflow duct, which has a first end held in a sleeve for regulating the water level in the pool and a second end connected to the sewer. A non-return valve is advantageously mounted on the overflow duct, between the first end thereof and the connection of the drainage duct 40, in order to allow water to flow from the pool to the sewer (in case of overflow) but to prevent backwashing water coming from the drainage duct 40 from going to the pool rather than to the sewer. In other pool configurations, the drainage duct 40 has a quick coupling 43 (Fig. 5b) at the tip thereof in order to allow a duct for draining away water to the sewers to be connected.

The immersed filtration device 100 may also comprise a grate basket 50 above the valve module 30 (Fig. 1a and 1b). A grate basket 50 of this kind prevents leaves or other relatively large objects from clogging the valve module 30.

Advantageously, the immersed filtration device 100 is held in a plastic compartment or shell 90 that is integrated into the pool 200 or into an element of the pool (e.g. a ladder) or placed on the edge of the pool 200 (Fig. 1b). Fig. 1b shows a truncated view of the shell 90, which is filled with water from the pool 200 over the entire height thereof.

In an advantageous variant, the immersed filtration device 100 has a pressure relief valve 23 that is positioned on a bypass 24 of the first outlet duct 22, for example, by means of a T-piece (Fig. 8a to 8d). Recall that the first outlet duct 22 and the bypass 24 thereof are immersed in the water of the pool 200 that fills the shell 90. The pressure relief valve 23 is therefore subject both to the water pressure of the pool 200 and to the water pressure in the first outlet duct 22. The function of said pressure relief valve is to open in order to bypass the filtration device 100, in filtration mode, when the negative pressure in the first outlet duct 22 reaches a certain threshold, said threshold being representative of at least partial clogging of the filtration device 200.

In practice, the pressure relief valve 23 may be in the form shown in Fig. 8a and 8b; the body of the pressure relief valve 23 is held in the closed position by a calibrated spring. When the negative pressure inside the first outlet duct 22 is able to counteract the action of the spring, the body of the pressure relief valve 23 moves towards the inside of the bypass 24, so as to allow water from the pool 200 to enter the first outlet duct 22. The filtration device 100 is thus bypassed. Clogging of said filtration device thus does not lead to damage, e.g. to the pump of the filtration system (which will be later described in more detail). In backwashing mode, the pressure of water flowing in the first duct 22 to the filtration column 10 assists, with the action of the spring, in keeping the body of the pressure relief valve 23 pressed (an O-ring ensuring sealing) and preventing communication with the water in the pool 200 outside the bypass 24.

In a variant, a rod system 25 is associated with the pressure relief valve 23 in order to allow manual operation of said relief valve 23 (Fig. 8c and 8d). For example, the rod system 25 may comprise a rod 25a connected to a cam 25b which, due to its shape and axis of rotation, presses on the body of the pressure relief valve 23 when the rod 25a is pulled, thus allowing water from the pool to pass into the first outlet duct 22 and bypassing the filtration device 100 (Fig. 8c). The open position is maintained owing to the shape of the cam 25b. To close the pressure relief valve 23, the rod 25a is pushed back to release the hard point of the cam 25b, thereby releasing the spring which thus automatically closes the pressure relief valve 23 (Fig. 8d). Said variant is particularly advantageous for obtaining the maximum water flow rate when using the counter-current swimming system in the pool 200.

In another advantageous variant, the immersed filtration device 100 has a multi-hole valve 15 at the second end 12 of the filtration bowl 10, between the bottom filter 14 and the first outlet duct 22 (Fig. 9a and 9b). In filtration mode, i.e. when water is flowing from the first end 11 of the filtration bowl 10 to the second end 12 thereof, the multi-hole valve 15 is configured to be in an open position and to allow filtered water to pass from the filtration bowl 10 into the first outlet duct 22 (Fig. 9a). In backwashing mode, i.e. when water is flowing from the second end 12 of filtration bowl 10 to the first end 11 thereof, the multi-hole valve 15 is configured to be in a closed position. Water coming from the first duct 22 and intended to pass through the filtration bowl 10 to clean said filtration bowl can then only pass through the openings provided in the body of the multi-hole valve 15. The openings are evenly distributed over the surface of the valve body. The multi-hole valve 15 allows better channeling and orientation of the flow of water coming from the first duct 22; this allows the sand column to be cleaned, without placing the sand in suspension. The design of the multi-hole valve 15 (diameter, number and positions of the openings), based on the ratio of the open surface area (openings) to the flow rate of incoming water, ensures the cleaning power, without causing disturbance. By way of example, the openings may have a diameter of around 2 mm and form an open surface area of between 3% and 20% of the surface area of the body of the valve 15. The use of a multi-hole valve 15 of this kind may be particularly advantageous for the second embodiment mentioned above, without a mesh basket 13, because the use of said valve limits the suspension of the sand and thus the risks of sand being dragged away via the drainage duct 40.

The invention also relates to a filtration system 150 for a pool 200, comprising an immersed filtration device 100 as described above and a pumping device 110. The pumping device 110 comprises a pump 111, the first outlet duct 22 for filtered water, and the second duct 60 for discharging filtered water into the pool 200. The pump 111 has an inlet 111a, where water is sucked in, and an outlet 111b, where water is discharged. The first outlet duct 22 for filtered water is connected to the second end of the filtration bowl 10. The second discharge duct 60 is connected to a discharge nozzle 70 immersed in the pool 200 (Fig. 6 and 7). It is noted that the filtration device 100 has been shown outside the pool 200 in Fig. 6 and 7 to facilitate visualization of the water circuits, even though said filtration device is immersed in the water in the pool 200, as described above. Advantageously, the pump 111 has a variable-speed drive. In addition to the advantage of saving energy during the start-up and shut-down phases of the pump 111, the variable-speed drive makes it possible to create optimized filtration and backwashing cycles, which allow the performance of the filtration device 100 to be increased in comparison with a constant-speed system.

Likewise advantageously, the motor of the pump 111 is brushless. The technology of this type of motor is designed to eliminate the contacts between the fixed parts (stator) and the moving parts (rotor), thus limiting friction and vibration and thereby reducing waste heat and wear of the mechanical components. In the context of the pumping device 110, the use of a brushless motor makes it possible to consume approximately 10% to 20% less energy than a conventional asynchronous motor, with an equivalent flow rate, while providing greater power than the asynchronous motor and having the advantage of having a constant operating torque from the start-up of the motor until the steady-state phase. The brushless motor may also reduce the overall size of the pump 111.

The pumping device 110 according to the invention is capable of causing water to flow selectively: • according to a filtration flow, from the first outlet duct 22 to the second discharge duct 60, • or according to a reverse flow, from the second discharge duct 60 to the first outlet duct 22, for backwashing the filtration bowl 10.

For this purpose, according to a first embodiment shown in Fig. 6, the pumping device 110 comprises a five-port valve 112. The connection configuration of the various ports 112a-112e to the other elements of the pumping device 110 allows the selective flow of water according to a filtration flow or according to a reverse flow. In practice, the five-port valve 112 is fluidically connected: • to the inlet 111a of the pump 111 via a first port 112a and a second port 112b; • to the outlet 111b of the pump 111 via a third port 112c; • to the outlet duct 22 for filtered water EF via a fourth port 112d; • and to the duct 60 for discharging filtered water EF into the pool, via a fifth port 112e.

In a first configuration, in which the first port 112a is in communication with the fourth port 112d, and the third port 112c is in communication with the fifth port 112e, the pump 111 causes water to be sucked at the second end 12 side of the filtration bowl, which allows water to flow according to the filtration flow. Due to the suction of the pump 111, water to be filtered EAF from the pool 200, which is received by the immersed filtration device 100 at the first end 11 of the filtration bowl 10, passes through the opening 31 of the valve module 30, crosses the filtration bowl 10 to be filtered (EF), exits through the outlet duct 22, and reaches the discharge duct 60 to finally be discharged into the pool 200 via the discharge nozzle 70 (flow shown by solid lines in Fig. 6).

In a second configuration, in which the second port 112b is in communication with the fifth port 112e, and the third port 112c is in communication with the fourth port 112d, the pump 111 causes water from the pool 200 to be sucked at the discharge nozzle 70, which allows water to flow according to the reverse flow for backwashing. Water sucked by pump 111 is then discharged into the outlet duct 22, then to the filtration bowl 10, in reverse flow, from the second end 12 to the first end 11 (flow shown by dashed lines in Fig. 6). The backwashing water thus becomes laden with particles clogging the elements of the filtration bowl 10 (bottom filter 14, sand column, possibly mesh basket 13) as said water reversely flows through the filtration bowl 10. Due to the presence of the valve module 30, the backwashing water cannot flow through the first end 11 and into the pool; said water is drained away via the drainage duct 40 located between the mesh basket 13 and the valve module 30.

In a second embodiment shown in Fig. 7, the pumping device 110 comprises two three-port valves 113, 114. The connection configuration of the ports 113a, 113b, 113c of the first valve 113 and the ports 114a, 114b, 114c of the second valve 114 to the other elements of the pumping device 110 allows the selective flow of water according to a filtration flow or according to a reverse flow. In practice, the first three-port valve 113 is fluidically connected: • to the inlet 111a of the pump 111 via the first port 113a thereof, • to the outlet duct 22 for filtered water EF, via the second port 113b thereof, • to the discharge duct 60 via the third port 113c thereof. The second three-port valve 114 is fluidically connected: • to the outlet 111b of the pump 111 via the first port 114a thereof, • to the outlet duct 22 for filtered water EF, via the second port 114b thereof, • to the discharge duct 60 via the third port 114c thereof.

In a first configuration of said second embodiment, in which the first port 113a and the second port 113b of the first valve 113 are in communication, and in which the first port 114a and the third port 114c are in communication, the pump 111 causes water to be sucked via the outlet duct 22 on the second end 12 side of the filtration bowl 10, which allows water to flow according to the filtration flow. Due to the suction of the pump 111, water to be filtered EAF from the pool 200, which is received by the immersed filtration device 100 at the first end 11 of the filtration bowl , passes through the opening 31 of the valve module 30, crosses the filtration bowl to be filtered (EF), exits via the outlet duct 22, and reaches the discharge duct 60 to be discharged into the pool 200 via the discharge nozzle 70 (flow shown in solid lines in Fig. 7).

In a second configuration, in which the first port 113a and the third port 113c of the first valve 113 are in communication, and in which the first port 114a and the second port 114b are in communication, the pump 111 causes water from the basin 200 to be sucked at the discharge nozzle 70, which allows water to flow according to the reverse flow for backwashing. Water sucked by the pump 111 is then discharged into the outlet duct 22, then into the filtration bowl 10, in reverse flow, from the second end 12 to the first end 11. The backwashing water thus becomes laden with particles clogging the elements of the filtration bowl 10 (bottom filter 14, sand column, possibly mesh basket 13) as said water reversely flows through the filtration bowl 10. Due to the presence of the valve module 30, the backwashing water cannot flow through the first end 11 and into the pool; said water is drained away via the drainage duct 40 located between the mesh basket 13 and the valve module 30.

In the two described embodiments, it is mentioned that water from the pool 200 is sucked at the discharge nozzle 70 in order to cause water to flow according to the reverse flow for backwashing. Advantageously, in order to meet the safety standards concerning the risk of suction at the discharge nozzle 70, which is directly accessible to the users in the pool 200, the filtration system 150 comprises two automatic safety valves 121, 122 that are positioned on two branches that communicate with the discharge duct 60, just before the discharge nozzle 70 (Fig.

). The two branches may be implemented, for example, as a T-piece mounted on the discharge duct 60. The first safety valve 121, on a first branch connected to the discharge nozzle 70, is configured to open when water is flowing according to the filtration flow, i.e. when filtered water EF is discharged via said nozzle 70. The first safety valve 121 is further configured to close when water is flowing according to the reverse flow for backwashing, i.e. when water from the pool is sucked. Water is thus prevented entirely from being sucked in directly via the nozzle 70. The second safety valve 122 is located on a second branch in communication with the inside of the shell or compartment 90 in which the filtration device 100 is held. Since said shell 90 is immersed, said shell contains water from the pool 200. The second safety valve 122 is configured to close when water is flowing according to the filtration flow, i.e. when filtered water EF arrives from the discharge duct 60. Moreover, the second safety valve 122 is configured to open when water is flowing according to the reverse flow for backwashing; water from the pool 200 is thus sucked inside the shell 90, which is a space that is not directly accessible to the users of the pool.

The filtration system 150 according to the invention, comprising the immersed filtration device 100 and the pumping device 110 according to either of the described embodiments, is an immersed filter system that is compatible with backwashing and thus limits steps for handling and manually washing the elements of the filter, as are usually carried out for immersed filters. The immersed filtration device 100 effectively prevents backflow of backwashing water into the pool 200, owing to the valve module 30, and allows this dirty water to be drained away via the drainage duct 40. The pumping device 110 offers an efficient and reliable solution for managing the water flow, according to a filtration flow and a reverse flow for backwashing.

The filtration system 150 may be used for any type of pool or swimming pool.

Of course, the invention is not limited to the described embodiments, and variants may be implemented without going beyond the scope of the invention as defined by the claims.

Claims

1. Submerged device (100) for filtering water from a pool (200), comprising a filtration bowl (10) having a first end (11) for collecting the water to be filtered (EAF) from the pool (200) and a second end (12) intended to be connected to a first outlet pipe (22) for the filtered water (EF), the device (100) being characterized in that it comprises: * a valve module (30), secured to the first end (11) of the filtration bowl (10), to block the backflow of water through the first end (11) during backwashing of the filtration bowl (10); * a drain pipe (40), in communication with the filtration bowl (10), to evacuate water from the filtration bowl (10) during backwashing; and in that: * the filtration bowl (10) is cylindrical in shape, * and the valve module (30) comprises a valve (32) that can be moved along a shaft (33) parallel to the axis of the filtration bowl (10), to release or close a valve opening (31), the diameter of said valve opening (31) being between 50% and 90% of the diameter of the cross-section of the filtration bowl (10).

2. Submerged filtration device (100) according to the preceding claim, wherein the drain pipe (40) comprises a deactivation valve (41).

3. Submerged filtration device (100) according to any one of the preceding claims, wherein the filtration bowl (10) is a sand filter (1) and comprises a column of sand under the valve module (31) and a floor filter (14) secured to its second end (12).

4. Submerged filtration device (100) according to the preceding claim, wherein the filtration bowl (10) comprises a mesh basket (13) between the valve module (31) and the sand column.

5. Submerged filtration device (100) according to any one of the two preceding claims, wherein the floor filter (14) has a cylindrical shape and is made of stainless steel or plastics wires.

6. Submerged filtration device (100) according to any one of the three preceding claims, comprising a multi-hole valve (15) having a plurality of apertures and arranged between the floor filter (14) and the first outlet pipe (22), said valve (15) being configured to be open when the filtration device (100) is in a filtration mode and to be closed when the device (100) is in a backwash mode.

7. Submerged filtration device (100) according to any one of the preceding claims, comprising a grate basket (50) arranged on the valve module (30), for coarse filtration of the water.

8. Submerged filtration device (100) according to any one of the preceding claims, comprising a relief valve (23) arranged in a bypass (24) at the first outlet pipe (22), for bypassing the filtration bowl (10).

9. Submerged filtration device (100) according to the preceding claim, comprising a linkage (25) for manually actuating the relief valve (23).

10. Filtration system (150) for a pool (200), comprising: Sa submerged filtration device (100) according to one of the preceding claims, Sa pumping device (110), comprising a pump (111), the first outlet pipe (22) for the filtered water (EF), and a second pipe (60) for discharging the filtered water (EF) into the pool (200); the pumping device (110) being able to circulate the water selectively, in a filtration flow, from the first (22) to the second (60) pipe, or in a counter-flow, from the second (60) to the first (22) pipe, for the backwashing of the filtration bowl (10).

11. Filtration system (150) for a pool (200) according to the preceding claim, wherein the pumping device (110) comprises a five-way valve (112), allowing the selective circulation of water in a filtration flow or in a counter-flow.

12. Filtration system (150) for a pool according to claim 11, wherein the pumping device (110) comprises two three-way valves (113, 114), allowing the selective circulation of water in a filtration flow or in a counter-flow.

13. Filtration system (150) for a pool according to any one of the three preceding claims, wherein the pump (111) comprises a variable speed drive.

14. Filtration system (150) for a pool according to any one of the four preceding claims, wherein the pump (111) comprises a brushless motor.

15. Filtration system (150) for a pool according to any one of the five preceding claims, comprising two safety valves (121, 122) respectively positioned on two branches of a tee arranged on the second discharge pipe (60): * the first safety valve (121) being configured to open when water is flowing in a filtration flow, the second safety valve (122) being closed, * the second safety valve (122) being configured to open when water is flowing in a counter-flow, the first safety valve (121) being closed.