* * *

The present invention relates to a tank configured to generate a flow of water inside it to perform physical activity in so-called "counter-current" conditions.

Nowadays, the use of tanks or pools for swimming or more generally training in so-called "counter-current" conditions, that is, wherein a user is hit by a moving fluid against which to oppose, for example by walking or swimming, is widespread.

The counter-current tanks allow physical activity to be carried out in a limited space compared to that necessary otherwise in a traditional type tank.

In general, a counter-current tank is configured to generate and maintain in circulation a flow of water along a ring path through the use of propulsion elements, such as a propeller immersed in water that can be rotated by a motor.

The tank has sections in succession to each other and in mutual fluid communication, configured to guide the flow of water along a propulsion section, wherein the propulsion members are present, up to a use section, accessible to a user, into which the water flow is introduced.

The propulsion section and the use section are mutually connected by means of elbow fittings, to form a closed loop or substantially ring path, by means of suitable connecting sections.

Documents US 2035835 and US 5005228 describe some examples of tanks for counter- current swimming.

The counter-current tanks of the known art suffer from some drawbacks with reference, in particular, to the presence of turbulence of the flow along the use section or, again, to the pressure drops along the loop path.

These turbulences do not allow the correct execution of physical activity, as the user not only finds himself having to counter the current that hits him but must necessarily continue to compensate his own arrangement to face the turbulence of the flow.

In addition, the head losses reduce the overall efficiency of the tank, understood as the ability to generate a ring flow and keep it constant during the use of the tank itself.

As is well known, in fact, a turbulent flow has a chaotic course, whirling without follow ordered trajectories as in the case of a laminar fluid.

Keeping the flow motion constant and uniform along the section of use is necessary to provide ideal conditions of use for a user. In practice, at the use section, the motion of the fluid must be maintained in a laminar regime or as close as possible to the laminar regime to generate a uniform current.

The difficulty of generating a laminar motion and keeping it constant along the section of use is more noticeable in the tanks that have small dimensions, since the perturbations due to the connection sections between the use section and the propulsion section occur with greater intensity.

The solutions of the prior art do not allow to guarantee a laminar motion of the flow along the section of use with reference in particular to small tanks, which can be installed in boats or for use in closed environments such as gyms or similar or, again, which can be installed in domestic environments.

The object of the present invention is to provide in a simple and efficient way a tank configured to force a water flow inside it along at least one loop path, to allow the execution of physical activity in counter-current conditions, that is to say in contrast to a current of water that at least partially hits a user inside the tank.

A further object of the present invention is to allow a safe use of the tub as well as to make it safe during the period of non-use.

Another purpose of the present invention is to provide a tank configured to perform counter-current physical activity of optimized dimensions, as part of a solution with reduced overall dimensions compared to those of the prior art solutions.

A further object of the present invention is to provide a tank that can be used for carrying out different activities in counter-current conditions and, for this purpose, configured to house any equipment necessary for performing specific counter-current activity.

A specific object of the present invention is a tank configured to perform physical activity in a counter-current regime comprising a swimming section, a propulsion section along which a fluid is forced, wherein the swimming section and the at least one propulsion section extend along a longitudinal direction, at least a first connecting section and at least a second connecting section for the connection, in fluid communication, of respective ends of the swimming section and of the propulsion section so as to define at least one ring path along which the fluid, a platform interposed between the at least one first connecting section and the at least one second connecting section, wherein the at least one first connecting section comprises a plurality of first curved channels, the at least one second connecting section comprises a plurality of second curved channels, wherein the platform can be movable between an intermediate lowered position, wherein is distal from an access opening to the swimming section and a raised position wherein it hermetically closes the opening preventing access to the swimming section, wherein the platform is optionally movable in a lowered position, in abutment or substantially in abutment against a bottom portion of the tank to act as a support surface.

According to another aspect of the invention, the at least one first connecting section can comprise a plurality of first curved channels with an increasing section starting from the at least one propulsion section towards the swimming section and wherein the at least one second section of connection can comprise a plurality of second curved channels with a decreasing section starting from the swimming section to the at least one propulsion section.

According to a further aspect of the present invention, the at least one first connecting section can comprise a plurality of first curved walls shaped like a "C" or "U" placed one inside the other, mutually decentralized and with the respective concavities facing towards the swimming section and the at least one propulsion section.

According to an additional aspect of the present invention, the at least one second connecting section can comprise a plurality of second curved walls shaped like a "C" or "U", arranged one inside the other, mutually decentralized and with their respective concavities facing the swimming section and the at least one propulsion section.

According to another aspect of the present invention, the tank can comprise at least a first deflector arranged at the at least one first connecting section and a second deflector located at the at least one second connecting section, wherein the first deflector and the second deflector are configured to reduce turbulence or detachment phenomenon of the flow at the end of the platform.

According to a further aspect of the present invention, the tank can comprise propulsion members configured to impart a momentum to a fluid included in the tank, wherein the propulsion members comprise at least one propeller operatively connected to a motor for its rotation drive, wherein the at least one propeller is arranged along the at least one second connecting section, below the platform.

According to an additional aspect of the present invention, the platform when placed in the intermediate lowered position can define a separation diaphragm between the swim section and the propulsion section, keeping separate a flow which is forced along the swimming section and a flow which is forced along the propulsion section in counter-current with respect to the flow along the swimming section.

According to another aspect of the present invention, the first deflector can be arranged along the at least one first connecting section, inside a cavity delimited by a first internal curved wall included in the at least one first connecting section, and the second deflector can be placed along the at least one second connecting section inside a cavity delimited by a second internal curved wall comprised in the at least one second connecting section.

According to a further aspect of the present invention, the first deflector can be connected to the first grid and the second deflector can be connected to the second grid.

According to an additional aspect of the present invention, the first deflector has a cross section with a decreasing path along the longitudinal direction with a direction starting from the at least one first connecting portion towards the swimming section.

According to another aspect of the present invention, the first deflector has a cross section configured as an ogive or drop element or a hydrodynamic element equipped with a rounded end placed inside the first internal curved wall, followed by it along the longitudinal direction with the direction of flow advancement, a descending portion that connects to the platform.

According to a further aspect of the present invention, the platform, the first deflector and the second deflector are mutually connected to define a single body comprised along the swimming section, movable between the lowered position and the raised position.

The advantages offered by the tank according to the invention are evident.

In particular, the tank according to the invention allows to generate a laminar flow inside it as part of a solution with optimized overall dimensions.

The tank according to the present invention also includes a section of use, i.e. the section along which a user can access, which has large dimensions compared to the overall dimensions of the tank itself.

Furthermore, the tank according to the present invention is configured to ensure high safety not only during its operation but also during inactivity periods.

The present invention will now be described, for illustrative but not limitative purposes, according to its preferred embodiments, with particular reference to the Figures of the attached drawings, wherein:

Figure 1 shows a schematic perspective view of a tank according to the invention in an operational configuration; Figure 2 shows a perspective view from above of a tank according to the invention;

Figure 3 shows a sectional side view of the tank according to the invention, in a further operational configuration;

Figure 4 shows a perspective view from above of the tank of Figure 3;

Figure 5 shows a top view of the tank of Figure 1;

Figure 6 shows a perspective view from above of a further embodiment of the tank according to the invention;

Figure 7 shows a top view of the tank of Figure 6;

Figure 8 shows a side sectional view of the tank of Figure 7;

Figures 9 and 10 shows further components of the tank according to the invention;

Figure 11 shows a further version of the tank according to the present invention;

Figure 12 shows some possible uses of the tank according to the present invention.

With reference to the attached Figures, it should be noted that the tank according to the invention is configured to generate and maintain a flow of water inside it, along at least a loop or substantially loop path.

With reference to Figures 1 to 5, an embodiment of the tank according to the invention is illustrated, indicated as a whole with the reference number 1.

The tank 1 comprises a use section or swimming section 2, inside which it is possible to carry out a physical activity in counter-current, a propulsion section 3, along which the fluid is forced, at least a first connecting section 4 and at least a second connecting section 5 for the connection, in fluid communication, of respective ends of the swimming section 2 and of the propulsion section 3 so as to define at least one loop path along which to push a fluid.

The tank 1, at a top portion, defines an opening 6 for accessing the use or swimming section 2 of the same tank 1 (see, for example, Figures 1 and 2).

In particular, the use or swimming section 2 and the propulsion section 3 are positioned one above the other or, in other words, the swimming section 2 starts from a top portion of the tank 1, while the propulsion 3 starts from a portion of the bottom of the tank 1.

In the following description reference will be made to a physical activity such as swimming, although it is understood that the tank 1 can also be used for the execution of a different physical activity, such as walking or pedaling or further counter-current exercises without any limitation (see Figure 12 illustrates equipment for carrying out activities such as hydrorunning, platform 32 or hydrobike, bicycle 33). The swimming section 2 and the propulsion section 3 extend along a longitudinal direction 7 of the tank 1 (see, for example, Figure 1).

Preferably, the swimming section 2 and the propulsion section 3 have a linear development.

The swimming section 2 is separated from the propulsion section 3 by a platform 8, which acts as a support base along the swimming section 2 itself.

The platform 8 is interposed between the at least one first connecting section 4 and the at least one second connecting section 5 (see for example Figure 1).

The platform 8, moreover, is configured to act as a mobile diaphragm to divide two counter-current flows present along respective sections of the tank 1, i.e. the flow of water along the swimming section 2 and that present along the propulsion section 3 The mobility of the platform 8 allows the tub 1 to assume different operating configurations, as better described below.

The at least one first connecting section 4 is configured to cause an inversion of the direction of advance of the fluid between the propulsion section 3 and the swimming section 2. In this regard, it should be noted that the at least one first connecting section 4 comprises a plurality of partitions or curved walls shaped like a "C" or "U" or similarly, arranged one inside the other, mutually spaced and decentralized and with their respective concavities facing the swimming section 2 and the propulsion 3.

With reference to what is illustrated in the attached Figures, the at least one first connecting section 4 includes four first curved walls 9, 10, 11 and 12 with increasing size starting from a first internal curved wall 9 towards a first external curved wall 12.

The first curved walls 9, 10, 11, 12 delimit inside at least a first connecting section 4 of the first curved channels for the passage, inside them, of respective water flows. Each first curved channel has a respective inlet section, interposed between the at least one first connecting section 4 and the propulsion section 3, and a respective outlet section, interposed between the at least one first connecting section 4 and the section swimming 2.

It should be noted that for each first curved channel, the inlet section has a smaller width than that of the respective outlet section. In practice, each first curved channel has an increasing variable section starting from the inlet section towards the respective outlet section (see Figures 1 and 3). In other words, each first curved channel has an increasing section along the direction of flow within at least one first connecting section 4, starting from the propulsion section 3 towards the swimming section 2.

The term amplitude refers to the area of the cross section with respect to the direction of advancement of the fluid within the first curved channels.

The at least one first connecting section 4 allows to divert and convey the flow coming from the propulsion section 3 towards the swimming section 2, in order to limit the turbulence present in the flow outcoming from the propulsion section 3.

The at least one second connecting section 5 has a similar conformation to that described in relation to the at least one first connecting section 4.

In particular, the at least one second connecting section 5 is configured to cause an inversion of the direction of advancement of the fluid between the swimming section 2 and the propulsion section 3 and comprises a plurality of curved walls or walls shaped like a "C" or "U" shaped one inside the other, mutually spaced, with the respective concavities facing towards the swimming section 2 and the propulsion section 3 and, therefore, opposed to the concavities delimited along the at least one first connecting section 4.

With reference to what is illustrated in the attached Figures, the at least one second connecting section 5 includes four second curved walls 13, 14, 15, 16 with an increasing size starting from a second internal curved wall 13 towards a second external curved wall 16.

The second curved walls 13, 14, 15, 16 delimit inside the at least one second connecting section 5 of the second curved channels for the passage of respective water flows, each of which has a respective inlet section, interposed between the swimming section 2 and the at least one second connecting section 5 and a respective outlet section, interposed between the at least one second connecting section 5 and the propulsion section 3.

It should be noted that for each second curved channel, the inlet section has a greater amplitude than that of the respective outlet section.

In practice, each second curved channel has a decreasing variable section starting from the inlet section towards the respective outlet section (see Figures 1 and 3) or, in other words, along the direction of the flow inside the tank 1, starting from the swimming section 2 towards the propulsion section 3.

In the attached Figures 1-5 the at least one first connecting section 4 and the at least one second connecting section 5 each comprise four baffles or curved walls, although it is understood that further versions are possible comprising a different number of curved walls according to specifications requirements, for example as a function of the dimensions of the at least one first connecting section 4 or of the at least one second connecting section 5 (or more generally of the tank 1).

The tank 1 comprises propulsion members configured to impart a momentum to a fluid comprised in the tank 1, pushing it along at least one closed path, preferably in a loop.

According to a preferred embodiment, the propulsion members comprise at least one propulsive propeller 17 operatively connected to a respective motor 18 for its rotation drive (see Figure 1 wherein two propellers are shown schematically represented as two cylindrical bodies or Figure 3 wherein a schematic sectional view of a propeller is shown).

Preferably, the tank 1 comprises two propellers 17 arranged along a direction transverse to the direction of advance of the flow. It is understood that the total number of propulsive propellers 17 can vary according to the dimensions of the tank 1.

The propulsion members are arranged at the propulsion section 3 or along it, according to specific use requirements.

Preferably, the propulsion members are positioned outside the plan area of the swimming section 2. In particular, the propulsion members are arranged outside the plan encumbrance of the platform 8, so as not to interfere with the movement of the itself.

The tank 1 comprises a first grid 19, interposed between the at least one first connecting section 4, the swimming section 2 and a second grid 20 interposed between the swimming section 2 and at least one second connecting section 5.

The first grate 19 and the second grate 20 are provided respectively to uniform the flow entering the swimming section 2 and that leaving it. Furthermore, the second grid 20 prevents a user from being sucked into the at least one second connecting section 5, in favour of safe operation of the tank 1.

The tank 1 comprises a first deflector 21 and at least a second deflector 22 arranged at respective end portions of the platform 8.

According to the embodiment illustrated in the attached Figures 1 to 5, the first deflector 21 is arranged along the at least one first connecting section 4, inside the cavity delimited by the first internal curved wall 7, while the second deflector 22 is arranged along the at least one second connecting section 5, inside the cavity delimited by the second internal curved wall 13.

More in detail, the first deflector 21 is connected to the first grid 19 and therefore kept in position inside the first internal curved wall 9.

Similarly, the second deflector 22 is connected to the second grid 20 and kept firmly in position within the second internal curved wall IB.

The first deflector 21 and the second deflector 22 are configured to uniform flow, reducing turbulence, at the internal portion respectively of the at least one first curved section 4 and of the at least one second curved section 5.

The first deflector 21 has a cross section with a decreasing path along the direction 7, with a direction starting from the at least one first connecting section 4 towards the swimming section 2, so as to reduce turbulence and pressure drops at one end of the platform 8 close to the at least one first connecting section 4.

According to a preferred embodiment, the first deflector 21 has a cross section configured as an ogive or drop element or, more generally, a hydrodynamic element provided with a rounded end, in particular the end which is arranged inside the first internal curved wall 9, followed by, along the flow forward direction, a descending, ramp portion, which is connected, at the opposite end, to the platform 8.

This conformation allows to avoid a detachment of the flow at the initial end of the platform 8, in order to reduce turbulence at the internal curved wall 9 or to avoid cavitation phenomena.

The second deflector 22 has a proximal end to the second rounded internal curved shaped wall 13, to favor the deviation of the flow along the at least one second connecting section 5.

According to an alternative embodiment illustrated by way of example in the attached Figure 11, the propulsion members comprise one or more centrifugal pumps, schematically indicated with 30, which suck water from the tank 1, taking it from the at least one second connecting section 5 and delivering it under pressure at the propulsion section 3, through suitably oriented nozzles, provided with Venturi tubes 31 to increase the flow rate.

The platform 8 is mobile between a lowered, intermediate lowered position, wherein it is distal from the opening 6 and arranged at a base portion of the tank 1 (see Figures 1 and 2) and a raised position, wherein it acts as a sealing the opening 6 (see Figures 3, 4 and 11. In particular, in the attached Figure 11, the platform 8 is shown in the raised position with solid lines and in the lowered position with dashed lines).

The platform 8 placed in the intermediate lowered position acts as a separation element, or rather acts as a separation diaphragm, between the swimming section 2 and the propulsion section 3, delimiting the swimming section 2 below and guaranteeing a support for a user inside the latter.

With the platform 8 arranged in the completely lowered or substantially completely lowered position, on the other hand, the tank 1 can be used to perform activities such as water aerobics, hydrospinning, hydrorunning or the like (see Figure 12).

The platform 8 arranged in the raised position provides a closing element for the tank 1, preventing access to the swimming section 2. In this regard, along the top portion of the tank 1, at the perimeter of the opening 6, are provided sealing elements which are configured to selectively abut against the edges of the platform 8 and thus guarantee the sealing of the closure which can be obtained by means of the platform 8 itself.

Selectively closing the access to the swimming section 2 of the tank 1 allows the safe use of the tank 1 itself, for example in boats, to prevent the use of the tank 1 or, more generally, to prevent access and prevent a user may accidentally fall into tank 1. Not only that, the platform 8, arranged in the raised position, can be walked on so that, when not in use, it does not limit the space available in the environment wherein the tank 1 is installed, for example a gym of a cruise ship.

Furthermore, with the platform 8 placed in the raised position to hermetically close the opening 6, the water from escaping from the tank 1 is prevented, for example following the movement of the boat wherein the tank 1 is installed. Furthermore, with the platform 8 in the raised position to hermetically close the opening 6, the accidental entry of water into the tank 1 itself is prevented, for example if the tank 1 is installed on a covered deck subject to flooding, to the advantage of safety of use of the tank 1 itself.

It should be noted that, with reference to the embodiment illustrated in the attached Figures 1-5, the first deflector 21 and the second deflector 22 can each comprise a respective shaped portion configured to meet, by means of shape coupling, with respective end portions of the platform 8 (see for example Figure 3).

By way of non-limiting example, the first deflector 21 can comprise an abutment portion which extends along the longitudinal development direction 7, inside the swimming section 2, and defines an abutment or a sealing lip which can be housed, by coupling shape, in a respective seat provided at one end of the platform 8. Similarly, the second deflector 22 can comprise a respective abutment portion which extends along the longitudinal development direction 7, inside the swimming section 2 and defines an abutment or a sealing lip which can be housed by means of a shape coupling in a respective seat made at one end of the platform 8 opposite to that which can be connected to the first deflector 21 (see Figure 3).

This shape connection between the first deflector 21 and the platform 8, as well as between the second deflector 22 and the platform 8, allows to obtain a sealed connection between the first deflector 21 itself, the second deflector 22 and the platform 8. As a fact, with the platform 8 in the lowered position, a tight barrier between the swimming section 2 and the propulsion section 3 is guaranteed, avoiding the generation of fluid leaks and, consequently, turbulence at the connection portions between both the first deflector 21, the second deflector 22 and the platform 8.

In the tank 1 according to the invention, the presence of a mobile platform 8, together with the presence of a first grid 19 and a second grid 20 provides an additional safety element in the use of the tub 1 itself.

The tank 1 comprises movement members configured to selectively move the platform 8 between the lowered and raised positions and intermediate positions.

In the attached Figures 1 to 5, the moving parts have been purposely omitted in order not to interfere with the intelligibility of the same, while they have been illustrated through discontinuous lines in the attached Figures 9 and 10.

The movement members comprise at least one motor unit 23 operatively connected to the platform 8 by means of motion transmission members and guide members configured to guide the platform 8 during its movement.

By way of non-limiting example, the motor unit 23 can be installed centrally along the platform 8, below it, and the motion transmission members can comprise a first transmission shaft 24 and a second transmission shaft 25 which are mirror-like to each other with respect to the motor unit 23 and connected to a power output of the latter by means of a transmission joint.

In turn, the first transmission shaft 24 is connected, by means of a gearing 26, to a first axle 27 located at one end of the platform 8, and the second transmission shaft 25 is connected, by means of a respective gearing 28, to a second axle 29 located at the opposite end of the platform 8 (see Figure 11).

The first axle 27 is configured to engage respective first racks (schematically illustrated in Figure 9 by means of dashed lines), meshing with them by means of pinions. The first racks act as guide members for moving the platform 8.

Similarly, the second axle 29 is configured to engage respective second racks (see Figure 9) at the opposite ends, distal from the gearing, engaging them by means of pinions. The second racks act as guide members for moving the platform 8 along the swimming section 2.

It should be noted that the movement members described above allow to obtain a smooth movement of the platform 8, preventing it from tilting, jamming, during the movement between the lowered and raised positions, and vice versa.

According to alternative embodiments, not shown in the attached figures, the moving members of the platform 8 can be configured in a different way and include, for example, motion transmission members provided with ropes and return pulleys operatively connected to a motor unit and to the platform 8, to obtain the movement of the latter along a guide between a lowered position and a raised position following the actuation of the motor unit itself.

As mentioned, the moving members, and in particular the motor unit 23, are arranged below the platform 8, so as not to clutter up the swimming section 2. Optionally, the moving members can be installed within the thickness of the platform 8, so as not to create an encumbrance below it, i.e. in the space present between the platform 8 and the bottom portion of the tank 1.

The attached Figures 6 to 8 illustrate a further embodiment of the tank according to the present invention, indicated as a whole with 100.

In the following, the same reference numbers increased by a further hundred units will be used to indicate the components corresponding to the previous embodiment.

The tank 100 differs from the previous embodiments in relation to the presence of two closed paths, preferably loop-shaped, side by side, along which respective water flows are forced.

In this regard, the tank 100 includes two propulsion sections 103, 103' which are arranged on opposite sides of the swimming section 102.

More in detail, the tank 100 comprises a first separating wall 140 which extends between the at least one first connecting section 104 and the at least one second connecting section 105 and is configured to separate the first propulsion section 103 from the section swimming pool 102 and a second separating wall 141 which extends between the at least one first connecting section 104 and the at least one second connecting section 105 and is configured to separate the second propulsion section 103 'from the swimming section 102.

In fact, the swimming section 102 is laterally delimited between the first grate 119, the second grate 120, the first separating wall 140 and the second separating wall 141 and below by the platform 108.

The swimming section 102, as well as the two propulsion sections 103, 103' extend for the entire height of the tank 100, intended as a dimension along the direction of movement of the platform 108.

The platform 108 is interposed between the at least one first connecting section 104 and the at least one second connecting section 105 (see for example Figure 6).

Similarly to what has been described in relation to the previous embodiment, the tank 100 comprises a first grid 119 configured to separate the at least one first connecting section 104 from the swimming section 102 and the at least one first connecting section 104 from the propulsion section 103.

The tank 100 also includes a second grid 120 to separate the at least one second connecting section 105 from the swimming section 102.

The tank 100 comprises members for moving the platform 108 between the lowered position, the intermediate lowered position and the raised position according to the methods described, by way of example, in relation to the previous embodiment to which reference is made.

The tank 100 comprises two first connecting sections 104 and two second connecting sections 105 for the mutual connection between a first propulsion section 103 and a portion of the swimming section 102 and between a second propulsion section 103' and a portion of the swimming section 102 (see Figure 7).

In particular, it should be noted that the tank 100, in plan, has a symmetrical conformation with respect to the longitudinal development direction 107.

In fact, in the tank 100 there are a first loop flow and a second ring flow which meet along the swimming section 102 with the same direction of advance (see Figure 7 wherein the trend of each of the two flows is highlighted by arrows).

According to a preferred embodiment, the first propulsion section 103 and the second propulsion section 103' each comprise a respective propeller 117 although it is understood that alternative embodiments comprising two or more propulsion propellers 117 along each propulsion section 103, 103' are possible.

The tank 100 comprises a platform 108 which, in turn, is provided with a first deflector 121 and a second deflector 122 mutually connected to the platform 108 itself, to form a single and movable body. In particular, the platform 108 is movable relative to the opening 106 between a lowered position, wherein it defines a bottom for the swimming section 102, an intermediate lowered position, wherein it is spaced from the bottom of the tub 100 and a raised position wherein it acts by closing for the opening 106 itself, preventing access to the swimming section 102 and providing a support surface that can be walked on when the tank 100 is not in use, in accordance with what is described in relation to the previous embodiment, to which reference is made.

It should be noted that also the two first connecting sections 104 and the two second connecting sections 105 are configured to eliminate or reduce as much as possible the effect of the turbulence caused by the propulsion members along the propulsion sections 103, 103', so to obtain a laminar or substantially laminar flow along the swimming section 102, similarly to the previous embodiment.

The person skilled in the art will easily understand how a tank 1, 100 according to the invention is able to achieve the intended purposes, generating and maintaining a laminar flow at a use or swimming section 2, 102.

Compared to the solutions of the known art which provide for a recirculation of the water inside the tank, to allow training in "counter-current" conditions, the tank 1, 100 according to the present invention allows to optimize the flow characteristics, obtaining a laminar regime along the swimming section 2, 102 as part of a solution with reduced dimensions and safe use.

In fact, the presence of a mobile platform 8, 108 allows you to occlude or open the opening 6, 106 of access to the swimming section 2, 102 respectively to prevent or allow access to the inside of the tank 1, 100 itself.

Furthermore, the possibility of moving the platform 8, 108 along the swimming section 2, 102 allows the tank 1, 100 to be used to perform swimming activities in counter-current or as well as further activities such as, for example, water aerobics, hydrobike or hydrorunning.

As mentioned, in fact, the platform 8, 108 can be lowered until it is brought in correspondence with the base or substantially in correspondence with the base of the tank 1, 100, thus acting itself as a support surface along which to arrange the tools necessary for carrying out the aforementioned physical activities.

According to a version of the present invention, preferably with the platform 8, 108 placed in this configuration, it is possible to activate the propulsion members in reverse, to generate propulsion with an opposite direction (counter-current) with respect to the orientation of any tools present inside the swimming section 2, 102, to allow the performance of physical activity in counter-current conditions or for specific needs of use.

In practice, the flow can be pushed starting from the propulsion section 3, 103, 103' towards the at least one second connecting section 5, 105, introduced into the swimming section 2, 102 and then introduced into the at least one first connecting section 4, 104 to then reach the at least one propulsion section 3, 103, 103' again.

The possible presence of a turbulent flow along the swimming section 2, 102, due to the positioning of the platform 8, 108 at the base of the tank 1, 100 is not an obstacle to the performance of a physical activity of the type indicated above.

Furthermore, it is highlighted how the platform 8, 108, in addition to acting as a closing element of the tank 1, 100 or as a support surface, when arranged in the lowered position, to mutually divide the swimming section 2, 102 and the propulsion section 3, 103, 103', acts as a dividing diaphragm between two branches of the flow inside the tank 1, 100.

In fact, the platform 8, 108 performs a triple function, albeit within the context of an overall simple and easy to use technical solution. In the foregoing, the preferred embodiments have been described and variants of the present invention have been suggested, but it is to be understood that those skilled in the art will be able to make modifications and changes without thereby departing from the relative scope of protection, as defined by the claims attached.