POWER GENERATION DEVICE FOR A SWIMMING POOL

Description

[0001] The present invention relates to a current generation device for a swimming pool.

[0002] Current generating devices for a swimming pool are known. Such devices comprise a cylindrical body along which the liquid flows, and a flow guide provided with at least one liquid inlet opening and at least one liquid outlet opening, the body being provided with a turbine and a propeller.

[0003] However, these devices can cause discomfort to swimmers due to turbulent flow and can send waves into their faces, as well as deflect them from their swimming axis as they swim.

[0004] Turbulent flow is characterized by the irregular movement of fluid particles. In addition, such devices are inefficient and therefore waste energy.

[0005] US4665572A describes an apparatus for mounting in a swimming pool to generate a laminar flow of water at a velocity sufficient for exercise and therapy. A housing is attached to the exterior of a swimming pool, with the water inlet and outlet disposed within the pool and supported by the outer housing. Water is forced through the inlet and upward by a rotating wheel to the outlet, which directs the flow of water substantially parallel to the surface of the pool. Diffusers are mounted within the water flow chamber.

[0006] The present invention aims in particular to remedy the drawbacks below by proposing a current generation device for a swimming pool providing a more pleasant counter-current swimming sensation, and being more energy efficient.

[0007] To this end, the invention relates to a current generation device for a swimming pool comprising a cylindrical body along which liquid can flow, and a hollow flow guide comprising a circumferential wall delimiting a liquid circulation channel, the flow guide being provided with at least one liquid inlet opening and at least one liquid outlet opening, the body being provided with a turbine arranged between the at least one liquid inlet opening and the at least one liquid outlet opening, in which the outlet opening is provided with a grid provided with a plurality of fins for directing the flow of liquid, the fins having a drop-shaped section with a leading edge oriented upstream and a trailing edge oriented downstream of the device, in which each fin has a Cx ratio of a maximum thickness over a length or chord of between 0.24 and 0.30, more particularly substantially equal to 0.27.

[0008] Thanks to the invention, the liquid expelled by the device follows a flow that tends to be laminar or sufficiently laminar to be pleasant for a swimmer, and the jolts are limited, so the swimmer is not bothered by waves arriving in the face. A laminar flow is characterized by regular trajectories of the particles of the fluid, unlike turbulent flow.

[0009] The liquid flow speed is also improved, and the power consumed is better utilized.

[0010] According to advantageous but not mandatory aspects of the invention, a current generation device for a swimming pool may comprise one or more of the following characteristics, taken in any technically possible combination in which: the device is symmetrical with respect to a longitudinal plane; the flow guide advantageously has a bent shape and passes from a cylindrical section in the vicinity of a propeller of the turbine to a rectangular section with rounded edges in the vicinity of the at least one outlet opening and in which the flow guide comprises a first liquid flow straightening blade extending in the longitudinal plane of symmetry; the fins comprise a plurality of aligned central fins and a plurality of end fins arranged on either side of the central fins, the end fins forming an angle of between 6° and 10° with the central fins, and being oriented towards the longitudinal plane of symmetry of the device; each central fin has a length or chord at least 1.5 times greater than a length or chord of each end fin;the device comprises a casing covering the body and the flow guide, in which a second liquid flow straightening blade is arranged on either side of the body and along the latter upstream of a propeller of the turbine and upstream of the flow guide; the casing is provided with a grid pierced with orifices allowing the liquid to be sucked into the casing and to flow from upstream to downstream along the body, the orifices of the grids being arranged only on either side of the longitudinal plane of symmetry; the device is suitable for being integrated into a swimming pool under construction; preferably the device comprises a horizontal platform connected to a vertical frame allowing the height of the device to be adjusted, the body being fixed to the horizontal platform; the device is suitable for being integrated into an existing swimming pool; preferably the device comprises a casing covering the body and the flow guide; ;

[0011] The invention and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a current generation device for a swimming pool, given by way of example and with reference to the appended drawings in which: [ Fig. 1 ] there Figure 1 is a front view of a current generation device for a swimming pool according to a first embodiment, the device comprising a flow guide provided with a grid; [ Fig.2 ] there Figure 2 is a longitudinal sectional view of the current generating device of the Figure 1 ; [ Fig. 3 ] there Figure 3 is a cross-sectional view of the grid of the device of the Figure 1 in perspective from above; [ Fig.4 ] there Figure 4 is a front view of a current generating device for a swimming pool according to a second embodiment; [ Fig.5 ] there Figure 5is a longitudinal sectional view of the current generating device of the Figure 2 ; [ Fig.6 ] there Figure 6 is a front view of a flux guide without a grid; and [ Fig.7 ] there Figure 7 represents several shapes of fins tested to make the grid of the Figure 3 .

[0012] On the Figure 1 a device 10 for generating current for a swimming pool according to a first embodiment is shown.

[0013] The device 10 comprises a cylindrical body 12 along which liquid can flow, and a hollow flow guide 14 comprising a circumferential wall 16 delimiting a liquid circulation channel 17.

[0014] The flow guide 14 is provided with at least one liquid inlet opening 18 and at least one liquid outlet opening 20.

[0015] The device 10 is preferably symmetrical with respect to a longitudinal plane P.

[0016] The liquid mainly consists of water and additives such as chlorine or salt.

[0017] The body 12 is for example made of metal or plastic.

[0018] Subsequently, it is determined that the liquid flows from upstream to downstream from the at least one liquid inlet opening 18 to the at least one liquid outlet opening 20.

[0019] The body 12 is arranged upstream of the flow guide 14.

[0020] The body 12 is provided with a turbine 22, visible on the Figure 2 .

[0021] The turbine 22 is configured to allow the circulation of liquid from upstream to downstream.

[0022] The device 10 has a propeller 24 placed downstream of the turbine 22. The propeller 24 makes it possible to transmit the power supplied by the turbine 22 to the liquid and thus to generate a current.

[0023] Propeller 24 is for example a three-bladed propeller.

[0024] Alternatively, the propeller has a different number of blades.

[0025] The flow guide 14 advantageously has a bent shape and passes from a cylindrical section in the vicinity of the helix 24 to a rectangular section with rounded edges in the vicinity of the at least one outlet opening 20.

[0026] Such a shape makes it possible to limit the size of the device 10 by placing it vertically in a swimming pool, and the outlet opening 20 opening horizontally so as to be perpendicular to the surface of the liquid contained in the swimming pool.

[0027] Advantageously, the liquid inlet opening 18 of the flow guide 14 has a cylindrical section contour, and having a diameter greater than a diameter of the body 12.

[0028] The body 12 and the flow guide 14 are for example assembled by means of a grid or sheet 25 screwed to the body 12 at one end and to the flow guide 14 at the other end.

[0029] Advantageously, the flow guide 14 comprises a single outlet opening 20.

[0030] The outlet opening 20 is provided with a grid 26 provided with a plurality of fins 28 for directing the flow of liquid.

[0031] The grid 26 preferably extends over the entire section of the outlet opening 20.

[0032] The fins 28 extend transversely to the flow guide 14 between two end faces 29.

[0033] Each end face 29 is in contact with the circumferential wall 16 of the flow guide 14.

[0034] As shown in the Figure 3 , the fins 28 have a drop-shaped section with a leading edge 30 oriented upstream and a trailing edge 32 oriented downstream.

[0035] Such a shape has the advantage of smoothing the flow of liquid from upstream to downstream and thus distributing the liquid according to a flow which tends to be laminar, as detailed in Example 1 below.

[0036] Furthermore, this makes it possible to increase the flow velocity at 1 meter from the outlet opening 20 of the device 10 to between 2 m / s and 3 m / s (meters per second).

[0037] Compared to a device without a grid, the flow rate at 1 meter from the outlet opening 20 of the device 10 is increased by approximately 20%. The liquid flow rate is between 180 m 3 < / h and 350 m 3 < / h in the presence of the grid 26.

[0038] Controlling water speed is important to improve swimmer comfort.

[0039] The Reynolds number characterizes the state of agitation within a liquid. The lower the Reynolds number, the more the flow tends to be laminar. Its expression is as follows: Re = V . Lc ν Where Re is the Reynolds number, V is the characteristic velocity of the fluid, L c is the characteristic length, determined by the geometry of the flow outlet device, v is the kinematic viscosity of the fluid. Here, the fluid used is water at 20°C, v=1x10 -6< m 2< .s -1< .

[0040] It is necessary that each fin 28 has a ratio Cx of a maximum thickness e over a length or chord ℓ of between 0.24 and 0.30, more particularly substantially equal to 0.27.

[0041] This ratio Cx is also called the drag coefficient.

[0042] The fins 28 having such characteristics are particularly hydrodynamic and the flow at the outlet of the flow guide 14 tends to be laminar.

[0043] The fins 28 comprise a plurality of aligned central fins 34 and a plurality of end fins 36 disposed on either side of the central fins 34.

[0044] Preferably, the central fins 34 have identical dimensions.

[0045] According to the example shown on the Figure 3 , the fins 28 comprise fifteen central fins 28 and eight end fins 36 distributed in groups of four on either side of the central fins 34.

[0046] Preferably, the fins 28 are regularly spaced from each other.

[0047] The spacing of the fins 28 determines the liquid passage section between the fins 28

[0048] The spacing between two consecutive fins 28 is chosen so as to be sufficient to limit the influence of these fins 28 on each other. Such a spacing is further evaluated so as to maintain a sufficient flow rate and acceleration of the fluid.

[0049] The end fins 36 form an angle α of between 6.0° and 10.0° with the central fins 34, and are oriented towards the longitudinal plane of symmetry P of the device 10.

[0050] Such an inclination makes it possible to better center the flow of the liquid which flows at the ends of the outlet opening 20.

[0051] Preferably, the end fins 36 form an angle α substantially equal to 8.0° with the central fins 34. Such an angle could be adapted in the case of a wider outlet opening 20 and / or an increased speed of the propeller 24.

[0052] Advantageously, the end fins 36 are shorter than the central fins 34 while satisfying the drag coefficient characteristics Cx of between 0.24 and 0.30, more particularly substantially equal to 0.27.

[0053] Thus, each central fin 34 advantageously has a length or chord ℓ at least 1.5 times greater than a length or chord ℓ of each end fin 36.

[0054] The fact that the end fins 36 are shorter also helps to better center the flow of liquid flowing out of the ends of the outlet opening 20, so that the flow of liquid through the center fins 34 and the end fins 36 is as parallel as possible.

[0055] The device 10 further comprises at least one blade 40, 42 for straightening the liquid flow.

[0056] The flow guide 14 comprises a first straightening blade 40.

[0057] The first blade 40 is preferably arranged downstream of the propeller 24, and upstream of the elbow formed by the flow guide 14.

[0058] Alternatively, the first blade 40 extends from the propeller 24 downstream of the propeller 24 to the grid 26.

[0059] The positioning of the first blade 40 relative to the propeller 24 is preferably as close as possible to the propeller 24 while maintaining a slight clearance so as to avoid friction of the propeller 24 which could occur during aging of the propeller 24.

[0060] The first blade 40 preferably extends in the longitudinal plane of symmetry P.

[0061] The first blade 40 is solid and is in contact on two sides with the circumferential wall 16 of the flow guide 14.

[0062] The first blade 40 improves the symmetry of the liquid flow as well as the liquid flow speed, which is more stable and avoids jolts.

[0063] The first blade 40 is a single blade. It is thus understood that the first straightening blade 40 does not have a plurality of blades, and in particular these are not arranged in a cross.

[0064] The flow guide 14 is advantageously produced by thermoforming, by assembling two symmetrical half-shells.

[0065] The device 10 optionally comprises a second straightening blade 42.

[0066] The second blade 42 is arranged on either side of the body 20 and along the latter upstream of the propeller 24 and the flow guide 14.

[0067] Preferably, the second blade 42 extends in the longitudinal plane of symmetry P, from the liquid inlet opening 18 to the propeller 24.

[0068] In the same way as for the first blade 40, the second blade 42 is preferably closest to the propeller 24 while maintaining a slight clearance so as to avoid friction of the propeller 24 which could occur during aging of the propeller 24.

[0069] The second blade 42 makes it possible to improve the liquid speed at the outlet of the flow guide 14. The flow speed is further stabilized, and the flow symmetry is improved.

[0070] The second blade 42 is particularly effective when the body 12 and the flow guide 14 are covered with a casing (not shown in the Figure 1 ).

[0071] The presence of a casing causes turbulence as the liquid flows along the body 12, and can generate pressure drops, cavitation and bubbles.

[0072] The second blade 42 makes it possible to remedy these drawbacks by smoothing the flow of liquid inside the casing and along it.

[0073] When a casing is present, a grid pierced with orifices is formed in the wall thereof in order to allow the entry of liquid inside it and which will then flow along the body 12.

[0074] The device 10 described in the first embodiment is suitable for being integrated into a swimming pool under construction. It is then necessary to provide a housing intended to receive the device 10.

[0075] For the installation of the device 10, the body 12 is fixed to a horizontal platform 50 connected to a vertical frame 52 allowing the height of the device 10 to be adjusted according to the user's preferences. The vertical frame 52 is advantageously provided with a chute allowing the protection of the electrical cables necessary for the operation of the turbine 22.

[0076] The body 12 is for example fixed to the horizontal platform 50 by means of nuts.

[0077] The body 12 and the flow guide 14 are for example fixed to the vertical frame 52 by means of nuts 56.

[0078] To use the device 10, the turbine 22 is put into operation. The liquid in the vicinity of the device is then sucked along the body 12, then enters the flow guide 14 from the inlet opening 18 to the outlet opening 20, and the flow is diverted between the fins 28 of the grid 26.

[0079] The flow of liquid at the outlet of the flow guide 14 is sufficiently laminar, symmetrical and provides pleasant swimming sensations.

[0080] Indeed, the more laminar the flow, the less visible the drag, and the less significant the edge effects. Thus, the more laminar the flow, the more pleasant swimming against the current is because the swimmer does not receive waves in his face and controls his position.

[0081] The presence of the grid described above makes it possible to increase the power felt without increasing the power absorbed.

[0082] THE Figures 4 And 5 represent a 10' current generation device for a swimming pool according to a second embodiment.

[0083] The device 10' described in the second embodiment is suitable for integration into an existing swimming pool.

[0084] Only the differences with the first embodiment will be detailed below.

[0085] The body 12 and the flow guide 14 are covered by a casing 60 making it possible in particular to dress the device 10 as well as to protect it, as it is not installed in a housing provided for this purpose in the swimming pool.

[0086] The second straightening blade 42 is present.

[0087] The liquid speed at 1 meter at the outlet of flow guide 14 is improved.

[0088] The flow velocity is stabilized.

[0089] The flow symmetry is improved.

[0090] In this embodiment, the casing 60 is provided with grids 62 pierced with orifices allowing the liquid to be sucked inside the casing 60 and to flow from upstream to downstream along the body 12.

[0091] The orifices of the grids 62 are arranged only on either side of the longitudinal plane of symmetry P.

[0092] Such an arrangement makes it possible to improve the efficiency of the second straightening blade 42.

[0093] For the installation of the device 10', the body 12 is fixed to a horizontal platform 50 connected to a vertical frame 52 allowing the height of the device 10 to be adjusted according to the user's preferences. The vertical frame 52 is advantageously provided with a chute allowing the protection of the electrical cables necessary for the operation of the turbine 22.

[0094] The vertical frame 52 is further provided with an L-shaped support 58 allowing the device 10' to be fixed to a pool edge.

[0095] The body 12 is for example fixed to the horizontal platform 50 by means of nuts.

[0096] The body 12 and the flow guide 14 are for example fixed to the vertical frame 52 by means of nuts 56.

[0097] Examples of tests carried out by the inventors to develop the device will be detailed below. Example 1 : tests with and without grid

[0098] The inventors carried out tests to determine the Reynolds number of the flow according to several configurations.

[0099] The Reynolds number is calculated as follows: Re = V . Lc ν Where Re is the Reynolds number, V is the characteristic velocity of the fluid, L c is the characteristic length, determined by the geometry of the flow outlet device, v is the kinematic viscosity of the fluid. Here, the fluid used is water at 20°C, v=1x10 -6< m 2< .s -1< .

[0100] The liquid considered is water at 20°C where v=1x10 6< m 2< .s -1< .

[0101] Kinematic viscosity and velocity are kept constant for each test.

[0102] Only the characteristic length varies in the following tests. Finless configuration :

[0103] The geometry considered initially is the flow guide without grid. In this configuration, the system returns to a flow in a rectangular pipe and the characteristic length of this flow is the hydraulic diameter Dh calculated as follows: D h = 4 A P

[0104] With A the area of ​​the outlet section (a rectangle in the case of the flow guide) and P the wetted perimeter, i.e. the entire perimeter in this case. D h = L C = 4 LB 2 L + B = 2 LB L + B

[0105] With L the length of the rectangle and B the width of the rectangle ( Figure 6 ). Configuration with fins:

[0106] The geometry considered is the flow guide with a grid provided with a plurality of fins extending transversely to the flow guide between two end faces. The fins have a drop-shaped section with a leading edge oriented upstream and a trailing edge oriented downstream of the device, in which each fin has a Cx ratio of a maximum thickness over a length or chord equal to 0.27.

[0107] The flow studied corresponds to that around the fins taken individually since the latter are sufficiently spaced so as not to influence one another. Here the characteristic length is therefore the chord ℓ of the fin (for bodies with less drag).

[0108] 2 types of fins are used in the grid, fins with chord ℓ = 20 mm and fins with chord ℓ = 32 mm. The thickness of the fins is determined using the drag coefficient, here equal to 0.27 as detailed in Example 2. The fins comprise fifteen central fins and eight end fins distributed by four on either side of the central fins.

[0109] The end fins form an angle of approximately 8.0° with the central fins, and are oriented towards the longitudinal plane of symmetry of the device.

[0110] The Reynolds number calculation for different speeds has been carried out and the results are grouped in the table below: [Table 1] Finless Flux Guide Flux Guide with Fins Reynolds difference without fin - 20 mm fin Ratio Without Fin / 20 mm Fin Reynolds difference without fin - 32 mm fin Ratio without Fin / 32 mm Fin Characteristic length [mm] Hydraulic Diameter Rope Fins 94,58130081 32 20 Flow velocity [m / s] Reynolds number 0,8 7,57E+04 2,56E+04 1,60E+04 59665,04 4,73 50065,04 2,96 1 9,46E+04 3,20E+04 2,00E+04 74581,30 62581,30 1,2 1,13E+05 3,84E+04 2,40E+04 89497,56 75097,56 1,5 1,42E+05 4,80E+04 3,00E+04 111871,95 93871,95 1,6 1,51E+05 5,12E+04 3,20E+04 119330,08 100130,08 1,8 1,70E+05 5,76E+04 3,60E+04 134246,34 112646,34 2 1,89E+05 6,40E+04 4,00E+04 149162,60 125162,60 2,2 2,08E+05 7,04E+04 4,40E+04 164078,86 137678,86 2,4 2,27E+05 7,68E+04 4,80E+04 178995,12 150195,12 2,6 2,46E+05 8,32E+04 5,20E+04 193911,38 162711,38 2,8 2,65E+05 8,96E+04 5,60E+04 208827,64 175227,64 3 2,84E+05 9,60E+04 6,00E+04 223743,90 187743,90 3,23 3,05E+05 1,03E+05 6,46E+04 240897,60 202137,60 3,4 3,22E+05 1,09E+05 6,80E+04 253576,42 212776,42 3,57 3,38E+05 1,14E+05 7,14E+04 266255,24 223415,24 3,8 3,59E+05 1,22E+05 7,60E+04 283408,94 237808,94 4 3,78E+05 1,28E+05 8,00E+04 298325,20 250325,20 4,2 3,97E+05 1,34E+05 8,40E+04 313241,46 262841,46 4,4 4,16E+05 1,41 E+05 8,80E+04 328157,72 275357,72 4,6 4,35E+05 1,47E+05 9,20E+04 343073,98 287873,98

[0111] The Reynolds number is almost 5 times lower for 20 mm fins and almost 3 times lower for 32 mm fins. The fin arrangement therefore promotes a less turbulent flow. Example 2: shape of the fins

[0112] The inventors tested the flow of water through the device using fins of several shapes, as shown in the Figure 7 .

[0113] The first fins (a) tested have a rectangular section, the large side of which is placed perpendicular to the direction of flow.

[0114] The results obtained with such a shape are poor, turbulence is created downstream of the fins and the flow is not oriented correctly.

[0115] The second fins (b) tested have a section in the shape of a solid half-oval, the rounded portion of the oval being oriented upstream and the flat portion being oriented downstream.

[0116] The results obtained are better than with a rectangular section, however the flattened shape downstream still generates turbulence.

[0117] The third fins (c) tested have a drop-shaped section, having a leading edge facing upstream and a trailing edge facing downstream.

[0118] The results obtained are much better than in the two previous tests. However, the results depend on a ratio between the thickness of the drop and the length or chord of the drop, this ratio being also called the drag coefficient (or Cx).

[0119] When the drag coefficient is less than 0.24, friction is too high and turbulence is created in one direction. When the drag coefficient is greater than 0.30, friction is also too high, and pressure drag is too high, therefore turbulence is created in a direction opposite to the first direction.

[0120] On the other hand, when the drag coefficient of each fin is between 0.24 and 0.30, more particularly substantially equal to 0.27, the fins are particularly hydrodynamic and the flow at the outlet of the flow guide tends to be laminar.

[0121] Thus, for a given length or chord, the thickness of the fin is determined by the product of the length of the fin and the desired drag coefficient.

Claims

1. A flow-generating device (10, 10') for a swimming pool, comprising a cylindrical body (12) along which liquid can flow, and a hollow flow guide (14) comprising a circumferential wall (16) delimiting a liquid circulation channel (17), the flow guide (14) being provided with at least one liquid inlet opening (18) and at least one liquid outlet opening (20), the body (12) being provided with a turbine (22) disposed between at least one liquid inlet opening (18) and at least one liquid outlet opening (20), wherein the outlet opening (20) is equipped with a grid (26) provided with a plurality of vanes (28) for directing the flow of liquid, characterised in that the vanes (28) have a drop-shaped cross-section with a leading edge (30) oriented upstream and a trailing edge (32) oriented downstream of the device (10, 10'), and in that each vane (28) has a Cx ratio of maximum thickness (e) to length or chord (ℓ) between 0.24 and 0.30, and more particularly substantially equal to 0.27.

2. The device (10, 10') according to claim 1, the device (10, 10') being symmetrical with respect to a longitudinal plane (P).

3. The device (10, 10') according to claim 2, in which the flow guide (14) advantageously has a bent shape and passes from a cylindrical section in the vicinity of a propeller (24) of the turbine (22) to a rectangular section with rounded edges in the vicinity of at least one outlet opening (20) and in which the flow guide (14) comprises a first blade (40) for straightening the liquid flow extending in the longitudinal plane of symmetry (P).

4. The device (10, 10') according to claim 2 or 3, in which the vanes (28) comprise a plurality of aligned central vanes (34) and a plurality of end vanes (36) arranged on either side of the central vanes (34), the end vanes (36) forming an angle of between 6° and 10° with the central vanes (34), and being oriented towards the longitudinal plane (P) of symmetry of the device (10, 10').

5. The device (10, 10') according to claim 4, wherein each central vane (34) has a length or chord (ℓ) at least 1.5 times greater than a length or chord (ℓ) of each end vane (36).

6. The device (10, 10') according to any one of claims 1 to 5, comprising a casing (60) covering the body (12) and the flow guide (14), in which a second blade (42) for straightening the liquid flow is arranged on either side of the body (20) and along the latter upstream of a propeller (24) of the turbine (22) and upstream of the flow guide (14).

7. The device (10') according to claim 6 when dependent on claim 2, in which the casing (60) is provided with a grid (62) pierced with orifices allowing the liquid to be sucked inside the casing (60) and to flow from upstream to downstream along the body (12), the orifices of the grids (60) being arranged solely on either side of the longitudinal plane (P) of symmetry.

8. The device (10, 10') according to any one of claims 1 to 7, wherein the device (10, 10') is adapted to be integrated into a swimming pool under construction, the device (10, 10') comprising a horizontal platform (50) connected to a vertical frame (52) allowing the height of the device (10, 10') to be adjusted, the body (12) being fixed to the horizontal platform (50).

9. The device (10, 10') according to any one of claims 1 to 8, wherein the device (10, 10') is adapted to be integrated into an existing swimming pool, the device (10, 10') comprising a casing (60) covering the body (12) and the flow guide (14).