Flow system for generating a counterflow

Abstract

A flow system is disclosed including a swimming pool and at least one flow device for generating a counterflow in the pool. The flow device includes at least one flow drive driven by at least one motor, and at least one drive channel in which a pressure difference between a drive channel inlet and a drive channel outlet can be generated by the flow drive. The drive channel inlet and drive channel outlet are arranged below a water line of the pool and the drive channel outlet is oriented to output the counterflow along a counterflow direction. The flow device, or a combination of at least two flow devices, includes at least one bypass channel having a bypass channel inlet and a bypass channel outlet. The bypass channel is at least partially spaced apart from a drive channel outer edge and is oriented substantially along the counterflow direction.

Description

TECHNICAL FIELD

[0001] The invention relates to a flow system comprising a water basin and at least one flow device for generating a counterflow for a subject in the water basin, wherein the flow device includes at least one flow drive which is driven by at least one motor of the flow device, and at least one drive channel in which a pressure difference between at least one drive channel inlet and at least one drive channel outlet can be generated by the flow drive, wherein the drive channel inlet and drive channel outlet are arranged below a waterline of the water basin, and wherein the drive channel outlet is arranged to output the counterflow along a counterflow direction.BACKGROUND

[0002] The purpose of a flow system or a counterflow system is to enable a subject, typically a person performing swimming movements, to be held in place in a water basin or swimming pool by providing a counterflow. By applying a defined volume flow at a defined flow velocity in the water, the subject may be kept in a fixed, constant, or consistent position relative to the water basin without reaching the edge of the water basin.

[0003] Prior art counterflow systems generally comprise a single flow outlet or drive channel outlet from which a counterflow is discharged in the direction of the swimmer. In some counterflow systems, a deflector element is also used to obtain a directed counter-current. A substantial disadvantage of known counterflow systems is that, despite the use of deflector elements or an adapted outlet shape, the actual movement cross-section or movement space of a swimming user is not supplied with a sufficiently homogeneous flow. Well-known counterflow systems also take up a lot of space when used in a water basin, or produce a weak counterflow.

[0004] A desirable homogeneous or homogenised counterflow is generally understood as a flow in the area of the subject that has little turbulence, swirling, and disturbance, and no asymmetrical flow profiles. Pulsations may also disturb movement in the water.

[0005] This desirable homogenised counterflow is, typically, not achieved in known counterflow systems. This circumstance can be explained by the fact that, when generating a counterflow or flow using a propeller as is predominantly the case, a swirl and a non-uniform velocity profile are inherently imparted to the counterflow. Similarly, deflecting a flow by means of an elbow may also impose swirling or inhomogeneous flow structures on the counterflow, which on the one hand are associated with higher dissipation and thus losses of kinetic energy of the counterflow, and on the other hand may disturb or prevent the steady movement of a subject.

[0006] Some of the counterflow systems in the prior art recognize these problems, but supply the movement space or reference space of a subject with a very inhomogeneous counterflow. Further, deflector elements or elbows cause large losses of kinetic energy of the flow and pressure losses due to narrowing or widening of the flow cross-section, or due to the flow through flow straightener openings and the associated increased friction or flow deflection. This requires more powerful flow drives, which typically take up a larger installation space.

[0007] Another problem with known counterflow systems is product safety. One of the most common causes of death among young children is drowning in water basins, including incidents caused by counterflow systems that have structurally caused hazards. For this reason, strict guidelines generally apply in public water basins in relation to counterflow systems.

[0008] Hazards, and thus product safety deficiencies, arise primarily from high negative pressures or suction pressures at the drive channel inlet of counterflow systems. Suction, especially of children and frail persons, increases the risk of drowning.

[0009] Another factor affecting product safety is that many well-known systems use a propeller as a flow drive to provide the counterflow. Long hair poses a particular risk, as many counterflow systems have to be configured very small due to space limitations in a water basin, which increases the likelihood of hair being drawn into the propeller. Here, the greatest hazard once again is possible drowning caused by hair getting caught or trapped in the propeller. Another potential hazard is becoming trapped under or behind a counterflow system.

[0010] A counterflow system according to the prior art is disclosed in EP3653275A1. The counterflow system is configured with a propeller coupled to a motor, to which a channel is connected, via which the water is fed into a water basin. The outlet nozzle may be configured such that the cross-section of the opening is oval-shaped.

[0011] A further example of a known counterflow system comprising a flow straightener or outlet diffuser is disclosed in U.S. Pat. No. 4,665,572A. This flow straightener is designed to provide a layered counterflow, wherein lamella-type structures or deflection elements are formed in the outlet of the flow in order to divide and straighten the counterflow.

[0012] DE2401040A1 discloses a counterflow system for swimming pools, wherein the water outlet nozzle has an adapted cross-section which is intended to provide a swimmer with a more favourable cross-sectional shape of the water flow with the same intensity, and is intended to require little effort. However, the problems and disadvantages described above are not sufficiently recognized in this counterflow system either.SUMMARY

[0013] In light of the prior art, the object of the invention may be seen as providing a solution to the above disadvantages of known counterflow systems. Primarily, a more compact solution than in the prior art is to be shown for providing a homogenised counterflow for a subject in a water basin, wherein the drive power required for this is not increased.

[0014] According to the invention, the present object is solved by a flow device of the flow system, or a combination of at least two flow devices, comprising at least one bypass channel having at least a bypass channel inlet and a bypass channel outlet, wherein the at least one bypass channel, is at least partially spaced apart from a drive channel edge, and wherein the bypass channel outlet is oriented substantially along the counterflow direction.

[0015] The at least one bypass channel offers two substantial advantages that contribute to solving the object.

[0016] Firstly, additional water is entrained through the bypass channel by the flow generated in the drive channel, such that the resulting counterflow provides an increased volume flow compared to a flow device without a bypass channel according to the invention, with the same drive power. This enables the motor and / or the flow drive of the flow device according to the invention to be made more compact, such that a smaller and more economical flow device may be provided overall. A more compact flow device is also easier to transport and set up, and also takes up less space in a water basin, providing more movement space for a subject.

[0017] Secondly, the at least one bypass channel provides a further inflow for entrained water, which supplies the counterflow or free jet or free jets from the drive channel with additional water. This results in a cross-section around the subject being broadly subjected to a counterflow over a large area. If no bypass channel were provided, in the event of a single free jet exiting from the drive channel, the circumference at which the free jet can entrain surrounding water would be limited to the outer circumference of the free jet. In the case of multiple free jets exiting the outlet cross-section of the drive channel, these free jets would merge into a single free jet due to the insufficient amount of water between the free jets. In both cases, this means that the cross-section in which the counterflow has an approximately homogeneous velocity distribution does not comprise the entire movement space of the subject. In the case of a swimming person, this results in an unnatural swimming sensation, as the cross-section of the counterflow around the swimming person does not have a sufficiently homogeneous velocity distribution.

[0018] A free jet is to be understood as a flow that is discharged into the free environment without wall restrictions via the outlet opening of the drive channel. The counterflow flowing out has a higher momentum than the water in the water basin and therefore also different velocities. A shear layer is created between them, through which surrounding water is drawn in and entrained. The bypass channels are gaps in the outlet opening, such that the circumference over which a shear layer may form is increased, while at the same time allowing sufficient water to flow in via the bypass channels such that it can be entrained. This has a beneficial effect on the volume flow of the counterflow and the homogeneity of its velocity distribution.

[0019] Further secondary advantages which may be provided by the at least one bypass channel when suitably dimensioned are indicated below.

[0020] The advantage may be achieved that the volume flow of water flowing through the bypass channel flows into the core area of the counterflow from the drive channel outlet, which results in an equalization or homogenization of the counterflow, since the flow in the core area is not uninfluenced by the external fluid and therefore moves forward unimpeded. The core area of the flow is to be understood as an area at the exit of the drive channel where, due to wall friction effects and the formation of boundary layers on the walls, there will always be a flow with areas that flow more slowly than others. The core area is the area that is not influenced by wall boundary layers, etc. The cross-section of the core area of a free jet decreases with increasing distance from the outlet opening as a result of the widening shear layer at the edge of the free jet. Since the at least one bypass channel is spaced apart from the drive channel outer edge, and water is drawn from it, the cross-section of the unimpeded core area is already reduced at the outlet opening. This results in homogenization, wherein at the same time the flow drive has to impart less energy to the flow in order to provide a counterflow of sufficient velocity and sufficient cross-section.

[0021] A further effect which may reduce the motor drive power required is that the return flow, which inevitably forms in the water basin due to the deflection of the counterflow at the water basin rear wall, is partially absorbed by the at least one bypass channel inlet in order to then be added back to the counterflow with its remaining undissipated and deflected flow velocity such that it can be directed once again back to the swimmer. In known counterflow systems, however, the counterflow and, subsequently, the deflected return flow are diffused uncontrollably at the water basin front wall, where the flow device is typically positioned, or deflected in such a way that they cannot be mixed into the flow of the drive channel by means of bypass channels in a directed manner.

[0022] Preferably, the bypass channel inlet is arranged behind the bypass channel outlet pointing against the counterflow direction, and the bypass channel inlet and bypass channel outlet are formed in a substantially straight line relative to their centres. This has the advantage that a return flow which is deflected by the water basin front wall may be absorbed particularly efficiently by the at least one bypass channel inlet. The straightness of the bypass channel leads to a particularly directed and conditioned counterflow, wherein, due to the absence of curvatures and other deformations or deflections, flow through the bypass channels and also filling of the core area of the flow can be particularly loss-free.

[0023] The centres may be understood as the centres equidistant from the edges of the respective bypass channel inlet and bypass channel outlet. The term ‘straight’ refers to the geometric shape of the connecting line or centre line of the respective centres.

[0024] In one embodiment, the flow drive and the motor may be located outside a frontal plane projection of the bypass channel outlet, wherein the bypass channel inlet is arranged spaced apart from the water basin. This has the advantage that the bypass channels are free of deflections, which means that water can be entrained from the water basin front wall with particularly little loss.

[0025] Preferably, the drive channel outer edge has the cross-sectional shape of an envelope of frontal planar projections of the subject below the waterline. As a result, a counterflow adapted to the subject may be provided, since only the relevant cross-section around the subject is subjected to a counterflow. Adapted counterflow means, for example, that the torso of a swimmer, which offers the greatest resistance to the counterflow in the prone swimming position, is particularly subjected to the flow. Firstly, if the counterflow only flows against this area, less motor power or drive power is required, as less water has to be accelerated around the swimmer. Secondly, this provides more space for the return flow, which inevitably has an inverse flow velocity compared to the counterflow, wherein the flow past each other is always associated with losses.

[0026] However, adapted counterflow should primarily be understood as the largest possible cross-section of the counterflow around the subject, such that a natural swimming movement or large-area flow around the subject is provided.

[0027] In one embodiment of the invention, the drive channel outlet may comprise a perforated plate with at least two holes through which the counterflow exits, wherein the holes may be dimensioned and arranged such that a counterflow that is as homogeneous as possible or a flow velocity that is the same from each hole can be provided. As a result, the advantage is obtained that an even more homogeneous counterflow can be provided for a swimmer or a subject being subjected to flow. It should be noted that the holes may also discharge the counterflow at an angle.

[0028] In a further embodiment, the drive channel has an elbow, wherein the elbow continuously transitions the cross-section of the drive channel inlet to the cross-section of the drive channel outlet. The elbow provides the advantage that the internal flow of the flow device is deflected and thereby undergoes a certain degree of preconditioning, such that a more homogeneous counterflow may be provided for the subject being subjected to flow. For this purpose, the interior of the elbow may be equipped with deflection plates, baffles, guide vanes, perforated plates or other elements for flow guidance and flow equalization.

[0029] Further, the elbow may have multiple flow channels, wherein the flow channels are individually connected to the holes of the perforated plate. As a result, the internal flow of the flow device is directed to each hole in order to obtain a particularly defined flow velocity from each hole. The flow channels are not limited to round cross-sections, but may also be oval or rectangular cross-sections, for example. Some of the holes may be designed as bypass channels.

[0030] If, in addition, a length and a diameter gradient and a flow channel curvature of the flow channels are dependent on their relative position to the flow drive and drive channel outlet, and designed such that a respective equal flow velocity exits from the holes and / or a counterflow for an adapted swimming sensation is obtained, the further advantage is obtained that it may be defined particularly precisely how the counterflow impinges on a subject. It is crucial for an adapted swimming sensation to manipulate the exit velocities in a targeted manner. This may mean that the exit velocity must be higher in the edge zone of the flow.

[0031] In one embodiment, a housing may spatially enclose the flow drive and the drive channel inlet at a distance, wherein the housing is adjustable in length to reach a bottom of the water basin. On the one hand, this has the advantage that elements of the flow system which pose a potential hazard can be shielded from a user or swimmer. On the other hand, the length adjustability prevents a swimmer or swimming subject from remaining under the flow device.

[0032] In a further embodiment, the housing may have a boundary surface with perforations, wherein the perforations are dimensioned such that an individual perforation has an opening surface of less than 1 cm2, preferably less than 0.5 cm2. The perforations may also have an opening diameter of less than 8 mm or greater than 25 mm. When arranged over a large area and in full numbers, these perforations prevent the formation of local flow peaks at which high suction pressures may occur, which could consequently lead to the suction of a swimmer or subject. Keeping the perforations small therefore increases product safety.

[0033] Advantageous and non-limiting embodiments of the invention are explained in more detail below with reference to the figures.DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a perspective view of a flow device of a flow system.

[0035] FIG. 2 is a front view of the flow device in FIG. 1.

[0036] FIG. 3 shows a detailed section of the perforated plate of the flow device shown in FIG. 1 and FIG. 2.

[0037] FIG. 4 shows a specific embodiment of an elbow.

[0038] FIG. 5 shows a flow system with a flow device in a water basin.

[0039] FIG. 6 shows a front view of a swimmer in a freestyle swimming movement, a contour of an outer edge of a drive channel, and a contour of the cross-section of the counterflow through which the water flows.

[0040] FIG. 7 shows a front view of a person in a walking or running movement, a contour of an outer edge of a drive channel, and a contour of the cross-section of the counterflow through which the water flows.

[0041] FIG. 8 shows a front view of a horse in a walking or running movement, a contour of a drive channel outer edge, and a contour of the cross-section of the counterflow through which the water flows.

[0042] FIG. 9 shows a front view of a dog in a swimming movement, a contour of a drive channel outer edge, and a contour of the cross-section of the counterflow through which the water flows.

[0043] FIG. 10 shows an embodiment of the flow device having a housing.

[0044] FIG. 11 shows an embodiment of a flow system in which the flow device terminates flatly with a water basin front wall.

[0045] FIG. 12 shows an embodiment of a flow system in which a drive channel 8 extends into a water basin.

[0046] FIG. 13 shows an embodiment of a flow system in which a drive channel extends outside the water basin, wherein a drive channel inlet draws water in the area of a side wall of the water basin.

[0047] FIG. 14 shows a specific embodiment of a flow device, wherein ten bypass channels are arranged in a funnel-shaped drive channel outlet.

[0048] FIG. 15 shows a specific embodiment of a flow device, wherein eight drive channel outlets are intersected by a grid-shaped bypass channel.

[0049] FIG. 16 shows an embodiment not according to the invention of a flow device, wherein the drive channel is formed to be X-shaped.

[0050] FIG. 17 shows a specific embodiment of a flow device, in which a flow device with two drive channels is illustrated.

[0051] FIG. 18 shows a sectional view of the flow device of FIG. 10 in a water basin.

[0052] FIG. 19 shows the flow device of FIG. 1 and a complete flow in a water basin from the drive channels and bypass channels.

[0053] FIG. 20 shows the flow system of FIG. 19 in a top view.DETAILED DESCRIPTION

[0054] FIG. 1 shows a flow device 3, comprising a flow drive 6 which is driven by at least one motor 7 of the flow device 3, and a drive channel 8 in which a pressure difference between at least one drive channel inlet 9 and at least one drive channel outlet 10 can be generated by the flow drive 6, wherein the drive channel inlet 9 and drive channel outlet 10 are arranged below a waterline 11 of the water basin 2, and wherein the drive channel outlet 10 is arranged to output the counterflow 4 along a counterflow direction 12. The flow device 3 has three bypass channels 13, wherein each bypass channel comprises a bypass channel inlet 14 and a bypass channel outlet 15, wherein each bypass channel 13 is spaced apart from a drive channel outer edge 16. The bypass channel outlets 15 are oriented along the counterflow direction 12. In the embodiment shown in FIG. 1, the bypass channels 13 penetrate the drive channel 8. It should be noted that the bypass channels 13 may also be openly connected to the drive channel outer edge 16. The flow device described in FIG. 1 is illustrated in FIG. 19 in the context of a flow system with a water basin and subject 5. FIG. 20 shows the flow system of FIG. 19 in a top view. The suction directions 24 of the bypass channels 13 and the suction directions 25 of the drive channel 8 are illustrated, wherein the flow direction 27 of the drive channel 8 and the flow direction 26 of the bypass channels 13 are also illustrated.

[0055] The flow drive 6 may also be understood as multiple propellers, pump wheels, impellers, or other working machines, both flow machines and positive displacement machines. The flow drive 6 may be driven by a single motor 7 or by multiple motors which are interconnected by a gear mechanism or another machine element. It should be noted that the flow drive 6 and the motor 7 do not necessarily have to be arranged within the water basin 2. Thus, the one or multiple motors 7 may also be accommodated outside the water basin 2. Similarly, the flow drive 6 may also be located outside the water basin 2, since only the drive channel inlet 9, drive channel outlet 10 and the at least one bypass channel 13 have to be located below the waterline 11 in order to be able to draw water from the water basin 2 and expel it again.

[0056] The motor 7 of the flow device 3 may also be a combustion engine, turbine engine, or even an electric motor. A 24-volt DC electric motor connected to a standard 230-volt power supply is preferably used. The counterflow that can be generated by such an electric motor may reach 1.45 meters per second, for example.

[0057] In the embodiment illustrated in FIG. 1, the flow drive 6 is a propeller arranged inside the drive channel 8. The flow drive 6 is rotated by a motor 7 in order to achieve the pressure difference necessary to impose a flow velocity to the water in the water basin 2. The motor 7 is connected to the flow drive 6 by a drive shaft. The motor 7 is cooled by the water flowing past its outer wall to enable continuous operation. The flow drive 6 is spaced so far apart from the drive channel inlet 9 and drive channel outlet 10 that even long hair of a swimmer 5 cannot become entangled, thus ensuring maximum product safety. Long hair may be understood to be hair with a length of 40, 50, or 60 cm or even longer.

[0058] As illustrated in FIG. 10, the drive channel 8, its drive channel inlet 9, and the flow drive 6 may be spatially enclosed by a housing 20. The drive channel inlet 9 is arranged spaced apart from the bottom of the housing, such that water may flow into the drive channel inlet 9 unhindered. The housing 20 is adjustable in length such that it may contact the bottom of the water basin 2 in the operating position to prevent a swimmer 5 from remaining and getting stuck under the flow device 3. Preferably, the adjustable length of the housing 20 can be adapted to a water basin depth of 1.2 to 1.6 meters, but lengths of 2 or 3 meters are also possible. The flow device 3 described in FIG. 10 is illustrated in FIG. 18 in the context of a flow system 1 with a water basin 2 and subject 5.

[0059] The housing 20 of the flow device 3 in FIG. 10 is configured with perforations over a large area of its boundary surface, with the exception of reinforcing ribs, which provide the housing 20 with high resistance to external impacts. These perforations serve primarily as a sieve or filter to capture debris from the water in order to keep the flow drive 6 and the motor 7, as well as the drive channels 8 and bypass channels 13, clear. Secondly, the fine-mesh perforations provide protection for the swimmer or swimming subject 5 such that no part of their body may come into contact with the flow drive 6. Preferably, the minimum distance that can be reached by a body part of the swimmer or swimming subject 5 on a minimal path to the flow drive 6 is at least 40 centimetres long. The perforations are configured such that even a child cannot stick their fingers through the perforations. The perforations preferably have a diameter of no more than 3 or 8 millimetres, and the flow velocity at the housing 20 is preferably less than 0.3 or less than 0.5 metres per second. The size of the perforations and their number and distribution may also be determined in accordance with the Public pool regulations. According to this law, the force exerted on standard hairs when pulled must not exceed 25 newtons.

[0060] The perforations may be hole-shaped or grid-like. The size, position and distribution of the individual perforations may depend on the flow drive 6 and its surrounding flow profile in order to compensate for local flow peaks and to achieve homogeneous suction across the entire perforated boundary surface. For example, smaller holes may be provided towards the drive channel inlet 9, which become larger with increasing distance from the drive channel inlet 9. The boundary surface of the housing 20 may also be configured with folds, which increase its surface area and thus reduce flow losses.

[0061] It should be noted that the part of the housing 20 contacting the ground may be designed with weight elements, such as sand or lead balls, which can be placed in a deformable membrane. As a result, unevenness or gaps at the bottom of a water basin 2 can be compensated for and, additionally, the flow device 3 can be prevented from floating up. Further, the flow device 3 has increased stability in the operating position due to the removable weight. Likewise, installation in a water basin 2 is facilitated, since the weight elements may only be added when the flow device 3 is placed in the water basin 2.

[0062] The flow drive 6 and the motor 7 of the flow device 3 of FIG. 1 are arranged along a vertical axis in order to take up as little surface area as possible in the water basin 2. In order to discharge the counterflow 4 in the desired counterflow direction 12, an elbow 19 is provided in the drive channel 8, wherein the elbow 19 continuously transitions the cross-section of the drive channel inlet 9 to the cross-section of the drive channel outlet 10. The elbow 19 may be equipped with guide plates, bends, deflection plates, internal flow straighteners, W-shaped collectors or Y-shaped collectors to specifically deflect the internal flow of the flow device 3. FIG. 14 shows a flow device 3 without an elbow.

[0063] The bypass channel inlets 14 facing against the counterflow direction 12 are arranged behind the corresponding bypass channel outlet 15, and the corresponding bypass channel inlet 14 and bypass channel outlet 15 are formed substantially in a straight line relative to their centres 17. FIG. 2, which shows the flow device 3 of FIG. 1 in a front view, clearly illustrates this feature. The three bypass channels 13 are free of curvatures in the front view, and the bypass channel inlets 14 and bypass channel outlets 15 are arranged one behind the other. It should also be understood that the bypass channels 13 may also be arranged at an angle to the counterflow direction 12. The bypass channel inlets 14 may be designed with rounded surfaces or chamfers for low-loss inflow.

[0064] It should be noted that the surfaces of the bypass channel inlets 14 and the bypass channel outlets 15 may have different shapes and sizes.

[0065] For example, the bypass channel outlet 14 may be smaller than the bypass channel inlet 15 in order to produce a nozzle effect in which the flow velocity through the bypass channel 13 increases towards the smaller surface area.

[0066] Further, the flow drive 6 and the motor 7 are located outside a frontal plane projection of the bypass channel outlet 15. In other words, there are no bulky elements in the path of the flow through the bypass channel 13 which could negatively influence the flow by necessary deflections or redirections or narrowings. It should be noted that the motor 7 could, for example, be located above the bypass channels 13 or outside the water basin 2, and only a thin drive shaft could lead through the frontal plane projection to the flow drive 6. It is not necessarily required that a flow drive 6 and a motor 7 are located outside a frontal plane projection of the bypass channel outlets 15. An example of this is the flow device 3 shown in FIG. 14.

[0067] Frontal plane projection can be understood as that in a front view of the flow device 3, as shown in FIG. 2, no other elements are intersected in the projection of the bypass channel outlets 15.

[0068] A further feature which the flow device 3 may have is a perforated plate 18 provided in the drive channel outlet 10. Wherein the perforated plate 18 is formed with at least two holes through which the counterflow 4 exits, wherein the holes are dimensioned and arranged such that a counterflow 4 which is as homogeneous as possible is provided. FIG. 3 shows a detailed section of the perforated plate 18 of the flow device 3 shown in FIGS. 1 and 2. It can be seen that holes near the bypass channels 13 are formed with a smaller diameter in order to accelerate the exit velocity from these by means of the nozzle effect, so that, with appropriate dimensioning of the remaining elements of the flow device 3, a particularly large amount of water is drawn along from the bypass channels 13. It should be noted that the perforated plate 18 may be designed in a grid-like or net-like manner. The holes in the perforated plate 18 may also be covered with a net or grid. It should further be noted that the holes may also be formed in a conical shape.

[0069] It can also be seen in FIG. 3 that the holes connected by rounded surfaces may protrude from a plane. Individual holes may protrude from this plane to different extents in order to facilitate the drawing along of water from the bypass channels 13.

[0070] The rounded surfaces are preferably formed not only on the outer side of the holes, but also on the inner side. This has the advantage that fewer losses occur when the flow is deflected into the holes. It should also be noted that the holes may also terminate smoothly with the perforated plate 18 or the mentioned plane. The perforated plate 18 may also be curved out of the plane in order to further homogenize the counterflow 4.

[0071] The holes of the perforated plate 18 may also discharge their respective flow at an angle in order to provide an adapted cross-sectional shape of the counterflow 4. Distribution devices, for example in the form of ball valve-like inserts, may also be provided in the holes in order to change the said angle or to reduce or close individual holes. The projecting holes may therefore also be designed as nozzles or diffusers in order to further homogenize the counterflow 4 and / or to adjust the cross-section of the counterflow 4.

[0072] It should also be noted that the perforated plate 18 itself may already have a curvature or may be deformed at an angle. Thus, in one embodiment of the perforated plate, a surface of the perforated plate in which the holes are arranged may be curved in order to direct the water flow or counterflow in a targeted manner. This allows a larger cross-section to be achieved in the relevant flow area or in the cross-section of the counterflow 23 of the applying subject 5. The drive channel outlet may also be configured from multiple curved surfaces that are inclined outward, wherein the bypass channels 13 are substantially aligned along the flow direction.

[0073] It should be noted that the holes in the perforated plate 18 may also be designed with closure elements, wherein the closure elements can change the diameters of the holes or close them reversibly to adapt the cross-section of the counterflow 4 to differently sized swimmers and also distances of the swimmer 5 from the flow device 3.

[0074] FIG. 4 illustrates a specific embodiment of an elbow 19 of a flow device 3 in sectional view. Multiple flow channels 21 are provided, wherein the flow channels 21 are each individually connected to the holes of the perforated plate 18. Particularly preferred are a length and a diameter gradient and a flow channel curvature of the flow channels 21, depending on their relative position to the flow drive 6 and drive channel outlet 10, such that an equal flow velocity exits from the holes. A particular advantage of this embodiment is that the flow channels 21 provide a longer distance for dissipating the swirling flow imposed by the elbow 19 or by the flow drive 6. Further, by dividing the flow among multiple flow channels 21, the imposed swirl is partitioned at an early stage and weakened by the flow channel wall and internal fluid friction. The flow channels 21 are guided in such a way that they do not collide with bypass channels 13.

[0075] Now referring to FIG. 5, which illustrates an entire flow system 1, the flow device 3 of FIGS. 1 and 2 being arranged in a water basin 2. It should be noted that the cross-section 23 of the counterflow 4 in the area of the subject 5, which in the case of FIG. 5 is a swimmer 5, swimming at a distance from the flow device 3, widens from the drive channel outlet 10 towards the swimmer 5. The drive channel outlet 10 therefore does not have to be the same size as the swimmer 5, although it is preferable that the drive channel outlet 10 has the cross-sectional shape of a transversely flat projection of a swimmer 5 below the waterline 11 in a prone swimming position with the arms crossed in front of the body. By the time the counterflow 4 reaches the swimmer 5, it has widened to such an extent that all common swimming movements, such as breaststroke, butterfly stroke and crawl stroke, can be reliably and specifically subjected to flow, without being subjected to flow more than necessary. The crawl stroke with the outlet shape described above is illustrated in FIG. 6.

[0076] It should also be mentioned that the cross-sectional shape of the drive channel outlet 10 or the drive channel outer edge 16 of the drive channel may also be formed as a round hole, oval or slot. Similarly, the size, number, orientation and cross-sectional shape of the bypass channels 13, in relation to the geometric design of the at least one drive channel outlet 10, can also be used to determine how far the counterflow 4 widens up until it reaches the swimmer 5 and which cross-section of the counterflow 4 actually reaches the swimmer 5. In this way, by drawing along water through the bypass channels 13, it is possible to obtain a non-circular cross-section of the counterflow 4 even from a circular cross-section of the drive channel outlet, given a suitable distribution. It should be noted that the edge condition of the water surface or waterline 11 also impacts the shape of the cross-section of the counterflow 23.

[0077] FIG. 6 shows the drive channel outer edge 16 as a dashed line and the cross-section of the counterflow 23 as a solid line. The same applies to FIGS. 7-9, wherein the respective drive channel outer edge 16 and thus the cross-section of the counterflow 23 is adapted to the subject 5 in each case. Specifically, the respective subject 5 is a walking human 5 in FIG. 7, a swimming or walking horse 5 in FIG. 8, and a swimming dog 5 in FIG. 9.

[0078] FIG. 11 shows an embodiment of a flow system 1 in which the flow device 3 terminates flatly or flush with a water basin front wall. It may also be appreciated that the water basin 2 has a water-bearing niche or recess in which the flow device 3 is located.

[0079] FIG. 12 shows a further embodiment of a flow system 1 in which a drive channel 8 extends into a water basin 2. It should be noted that the drive channel 8 may also be arranged at any position in the water basin 2.

[0080] FIG. 13 shows yet another embodiment of a flow system 1 in which a drive channel 8 runs outside the water basin 2, wherein a drive channel inlet 9 draws water in the area of a side wall of the water basin 2.

[0081] FIG. 14 illustrates another embodiment of a flow device 3, wherein ten bypass channels 13 are arranged in a funnel-shaped drive channel outlet 10. It should be noted that, in a frontal plane projection, the flow drive and motor 9 are arranged one behind the other.

[0082] FIG. 15 illustrates another embodiment of a flow device 3, wherein eight drive channel outlets 10 are intersected by a grid-shaped bypass channel 13. It should be noted, that the bypass channel 13 is connected to an imaginary drive channel outer edge 16 (illustrated as a dashed line), wherein the bypass channel 13 is still at least partially spaced apart from the imaginary drive channel outer edge 16.

[0083] FIG. 16 illustrates an embodiment not according to the invention of a flow device 3, wherein the drive channel outlet 10 is formed to be X-shaped, and of four groove-type bypass channels 13, which are at least partially spaced apart from an imaginary drive channel outer edge 16 of the drive channel (shown as a dashed line).

[0084] FIG. 17 illustrates another embodiment of a flow device 3, wherein the flow device 3 is illustrated with two drive channels 8. The two drive channels 8 are centrally intersected by a bypass channel 13. It should be noted that, in order to obtain the embodiment shown in FIG. 17, two separate flow devices 3 may also be combined in a combination Z. For example, any number of flow devices 3 of FIG. 16 may also be arranged next to each other to obtain a flow system 1 which can discharge a counterflow 4 from an entire wall of a water basin 2.

[0085] It should also be noted that the flow drive may also be designed with multiple counter-rotating propellers or as a propeller with a guide vane in order to reduce the swirl imposed on the counterflow.

[0086] Similarly, the at least one bypass channel may be covered with rounding radii in order to achieve a more favourable inflow or outflow of water from it. The drive channel inlet and / or the drive channel outlet may also be provided with rounding radii.

[0087] Another way to get a swirl-free flow is to use two opposite drive channels that meet in a Y or T shape, each with its own flow drive. The swirl is produced in opposite directions and with the same magnitude by each flow drive to discharge a swirl-free flow overall.

[0088] It is also conceivable to provide adjustable deflector elements or closing elements on the drive channel and / or bypass channel. This would allow two separate counterflows for two swimmers or swimming subjects to be provided efficiently in the same water basin at the same time. Thus, by means of the adjustable closure elements, a strong and a weak counterflow could be provided for the respective swimmers or swimming subjects. It would also be conceivable to direct the counterflow to the edge region of the water basin in order to obtain an annular flow without changing the installation angle of the flow device.

[0089] It should also be mentioned that the flow system may firstly be provided as a built-in system, wherein the flow device is integrally installed in the water basin. Secondly, the flow system may also be provided such that the flow device is removable from the water basin, wherein it may be designed to be suspended on the edge of the water basin.

[0090] Finally, it should be noted that in one embodiment, the drive channel outer edge may have the cross-sectional shape of the combinatorial envelope of transversely flat projections of a swimmer in a breaststroke, butterfly stroke and crawl stroke below the waterline. As a result, a particularly efficient counterflow is provided from the drive channel outlet, since only the most relevant cross-section around a swimmer is subjected to a counterflow.

Claims

1. A flow system comprising:a water basin;at least one flow device for generating a counterflow for a subject in the water basin, the flow device comprising at least one flow drive which is driven by at least one motor of the flow device, and at least one drive channel in which a pressure difference between at least one drive channel inlet and at least one drive channel outlet can be generated by the flow drive, wherein the drive channel inlet and drive channel outlet are arranged below a waterline of the water basin, and wherein the drive channel outlet is configured to output the counterflow along a counterflow direction,wherein the flow device, or a combination of at least two flow devices, further comprises at least one bypass channel having at least one bypass channel inlet and one bypass channel outlet, the at least one bypass channel being at least partially spaced apart from a drive channel outer edge and the bypass channel outlet being oriented substantially along the counterflow direction, andwherein the drive channel of the flow device or the combination of at least two flow devices is intersected by the at least one bypass channel.

2. The flow system according to claim 1, wherein the bypass channel inlet faces against the counterflow direction, and is arranged behind the bypass channel outlet and the bypass channel inlet and bypass channel outlet are formed substantially in a straight line relative to centers of the bypass channel inlet and bypass channel outlet.

3. The flow system according to claim 1, wherein the flow drive and the motor are located outside a frontal plane projection of the bypass channel outlet, and the bypass channel inlet is spaced apart from the water basin.

4. The flow system according to claim 1, wherein the drive channel outlet outer edge has a cross-sectional shape of an envelope of frontal plane projections of the subject below the waterline.

5. The flow system according to claim 1, wherein the drive channel outlet has a perforated plate with at least two holes through which the counterflow exits, wherein the holes are dimensioned and arranged such that a counterflow that is as homogeneous as possible, or an equal flow velocity, is provided from the each of the holes.

6. The flow system according to claim 1, wherein the drive channel has an elbow, wherein the elbow continuously transitions the cross-section of the drive channel inlet to the cross-section of the drive channel outlet.

7. The flow system according to claim 1, wherein a housing encloses the flow drive and the drive channel inlet, wherein the housing is adjustable in length in order to reach a bottom of the water basin.

8. The flow system according to claim 7, wherein the housing has a boundary surface with perforations.

9. The flow system according to claim 6, wherein the elbow has multiple flow channels.

10. The flow system according to claim 9, wherein a length and a diameter gradient and a flow channel curvature of the flow channels are dependent on their relative position to the flow drive and drive channel outlet such that a respective equal flow velocity exits from the holes and / or a counterflow is achieved for an adapted swimming sensation.

11. The flow system of claim 8 wherein the perforations are dimensioned such that an individual perforation has an opening surface of less than 1 cm2.

12. The flow system of claim 11 wherein the individual perforation has an opening surface of less than 0.5 cm 2.

13. The flow system of claim 11 wherein the individual perforation has an opening diameter of less than 8 mm.

14. The flow system of claim 11 wherein the individual perforation has an opening diameter of greater than 25 mm.

15. The flow system of claim 9 wherein the drive channel outlet has a perforated plate and the flow channels are individually connected to the holes of the perforated plate.

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