GB2602352A - Apparatus for use in a liquid pool - Google Patents

Abstract

An apparatus for use in a liquid pool 20 comprising a movable support with a buoyancy body 120 (fig.1b) is configured to move between upper and lower positions. The apparatus comprises a plurality of tendons 200 (fig.1b) connecting the support to the bottom of the pool said tendons being in tension when the support is in the upper position. The buoyancy body is configured to be filled with and have air removed causing it to rise or lower respectively. The upper position may be above the liquid surface or between the surface and the bottom of the pool. The buoyancy body may comprise a means for controlling the rate of flow of air from said body, the means comprising a portal 130 (fig.1a) and a mechanism 132 (fig.7a) for closing the portal. Also disclosed is a system with a plurality of these apparatuses, wherein each support moves independently, and a method of covering a swimming pools rigid floor using the described apparatus.

Description

Apparatus for use in a Liquid Pool The invention relates to an apparatus for us in a liquid pool. In particular it relates to an apparatus comprising a movable support which can be raised or lowered and a method of operating the same.

Swimming pools pose safety hazard for people, especially children, drowning in the water when unattended. This problem may be solved by providing a rigid floor above the water. The surface area of the swimming pool may also be used as part of the surrounding terrain especially if the floor above the water is at the same level and it does not sink as people move on and off this area.

There are different methods of providing such floors, for example by varying the level of the floor using scissor mechanisms, pistons, lifts. The use of air to increase the buoyancy and lift the floor has been known. Holding the floor in place when load is imposed on it is achieved by providing for example supports, pillars.

US Patent 4283801 discloses a pool equipped with a combination surface deck and height-adjustable pool floor in which the height is altered by way of external low pressure hydraulic cylinders operated from the pool circulating system. US publication 2007/0220667 discloses a pool cover that doubles as a deck. It is necessary to provide a mechanical lift device.

WO 2011/077377 discloses a retrofit, submersible deck for a swimming pool including a buoyancy adjustable panel in operative connection with a ballast system and a leg support for changing the effective swimming pool depth and increasing deck area.

Invention WO 201 3/1 06891 Al discloses a swimming pool floor system for installation in a swimming pool that consists of a swimming pool floor that can move vertically in a swimming pool filled with water in order to achieve various vertical use positions in which the swimming pool floor floats in water or can be made to float, characterised as such that a continuous layer is formed over the surface of the swimming pool floor by at least a part of the chambers in which the layer is formed by at least two horizontal synthetic plates connected by ribs that define the chambers together with the plates. The system is fitted with supports for the swimming pool floor that can be folded in a storage position and a folded-out support position.

WO 2018/091854 Al discloses a system for raising /lowering a submersible structure within a volume of water, comprising at least one lifting pillar comprising a sealed and non-elastic envelope, and a hydraulic system comprising a pump connected to casing for filling casing with water from the volume of water, the lifting pillar being configurable between a retracted configuration in which the envelope is empty of water in order to allow the submersible structure to be in the low position; and a deployed configuration in which the casing is filled with water in order to support the submersible structure in the high position.

Prior art of rigid floors in swimming pool covers make use of supports, pillars, scissor mechanisms to prevent the floor from moving downwards when load is imposed on the floor.

A method used in offshore engineering in holding floating platforms at a constant vertical elevation is the use of Tension Leg Platforms (TLP). A tension-leg platform is a vertically moored floating structure normally used for the offshore production of oil or gas. The buoyancy on the submerged bodies is higher than the weight of the structure. The platform is moored by means of tethers or tendons grouped at each of the structure's corners.

US 3,780,685 (1973) for example discloses a tension leg offshore marine apparatus having buoyant bodies restrained by tendons. Tension leg principle is also used for example in supporting offshore wind turbines, as for example disclosed in US 9,902,468,01 B2 (2018). The tendons are held down by for example dead weights, anchors, piles.

Viewed from a first aspect, there is provided an apparatus for use in a liquid pool comprising a movable support which has a buoyancy body and is configured in use to move between a lower position and an upper position, and the apparatus further comprising a plurality of tendons which in use are configured to connect said support to the bottom of the pool, said buoyancy body being configured to be filled with air, so that when said support is at the lower position in the pool and air enters said body to increase its buoyancy said support rises from said lower position to said upper position to be restrained by said tendons, said tendons being configured to be in tension when said support is at said upper position, and said buoyancy body being configured to have air removed therefrom to cause said support to sink from the upper position to the lower position. The pool may be a swimming pool. 3 -

The buoyancy body may be configured to be filled with air so that its buoyancy is such that the tendons are in tension when a load of up to 2 kN/m^2 is applied on said support.

The buoyancy body may be configured to be filled with air so that its buoyancy is such that the tendons are in tension when a load up to 10kN/m^2 is applied on said support.

The buoyancy body may be configured to be filled with air so that its buoyancy is such that the tendons remain in tension when a load of 0.5 kN/m^2 is applied to the support.

The buoyancy body may be configured to be filled with air so that its buoyancy is such that the tendons remain in tension when a load of 0.5-10 kN/m^2 is applied to the support.

In practice, the load on the support may be uniformly distributed or applied at different areas or points on the support. When assessing a given apparatus in which the tendons are in tension at a specified load or range of loads as stated herein, unless otherwise specified the load or range of loads may be considered as uniformly distributed across the support.

The upper position may be above the liquid level. It may also be an intermediate position between the bottom of the pool and the liquid level.

The buoyancy body may comprise a means for controlling the rate of flow of air from said buoyancy body.

The means for controlling the flow of air may comprise a portal through which air may pass, and a closing mechanism configured to prevent the passage of air through said portal.

The buoyancy body may further comprise an air release mechanism including a hollow body configured to urge the closing mechanism downwards through the portal, wherein the hollow body comprises a plurality of apertures for allowing air to travel through said portal.

The closing mechanism may be a non-return flap valve and may be spring operated wherein the spring force is configured to urge the flap valve into a closed position wherein the portal is blocked.

In use the air escapes through said portal of said buoyancy body from the plurality of apertures in the hollow body thereby causing the buoyancy body to fill with liquid and the apparatus to sink, wherein the closing mechanism is configured to be urged upwards to automatically close said portal.. 4 -

The apparatus may comprise a dead weight configured to be located on the bottom of said liquid pool, wherein the plurality of tendons are connected to said dead weight.

Viewed from another aspect there is provided a plurality of apparatuses as set out in the first aspect, wherein each support moves independently thereby stepped bottom floors may rise and form a planar top surface.

Viewed from another aspect there is provided an apparatus for use in a pool floor which is sloping, comprising tendons of different lengths to configure the movable floor to be sloping when down and flat with grade when up.

Viewed from a further aspect, there is provided a method of covering a swimming pool with a rigid floor using the apparatus of the first aspect.

In aspects of the invention above, the support may include a support surface or deck.

In use in a liquid pool the apparatus comprising the surface may form the bottom of the pool when people swim in the pool and when moved at a high position it may form a support where people may stand, sit, play or use otherwise. The invention also relates to a method for moving and holding a support in a liquid pool.

The invention applies the principle of a tension leg structure for supporting imposed loads on the support with the principle of lifting and sinking bodies by changing the submerged weight of the body through the addition or subtraction of air from the body.

A body is provided under the floor surface which may be filled with air. The vertical movement up and down of the floor is controlled by the amount of air inside the body. When there is not enough air in the body the floor sinks and it forms the bottom of the pool. When air enters and gets trapped inside the body hydrostatic pressure urges the body upwards. The upward force, known as buoyancy, B, equals the weight of displaced liquid, as first discovered by Archimedes, and it is known as Archimedes principle. When buoyancy, B, exceeds the gravitational force (weight), W, (B>W) the body moves upwards. If the body is loose then the body will rise to such a level that the weight of the structure (floor, body, content of body), W, equals buoyancy, B, (B=VV). If however the body is connected to the bottom of the pool by tendons, then the elevation of the floor is determined by the length of the tendons and the tendons are tensed with a force, T, which is equal to the difference between the buoyancy, B, and the weight, W.

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T = B -W Eqn. 1 When the floor is up at the same elevation as the surrounding terrain, the floor may be used as a patio, deck, playground, or any other suitable use. The swimming pool floor cover is designed to withstand the imposed load, Q, for the intended use without moving downwards. The tension in the tendons when the floor is loaded, T', must therefore never be slack otherwise the floor will move downwards or start sinking.

B-W-Q >0 Eqn. 2 The lower end of the tendons may be affixed to the bottom of the pool, for example cast into the concrete base of the pool, welded or bolted to the steel bottom of the pool, attached to a deadweight resting on the pool or any other method.

If the tendons are attached to a deadweight on the pool bottom, then the submerged weight of the deadweight, W (the weight of the deadweight in air minus the buoyancy action on the deadweight) must be greater than the tension in the tendons, T, when the floor is unloaded.

W' > T Eqn. 3 From eqn. 2 Q < B -W Eqn. 4 From eqns 3 and 1 W' > B -W Eqn. 5 From eqns 4 and 5 W' > Q Eqn. 6 The raising and lowering of the pool floor is achieved by controlling the amount of air and liquid in the body. The body may for example be inflatable, rigid, or combination. When the body is filled with liquid then it has the maximum weight and when it is filled with air the minimum weight. The body has a portal through which air or liquid may pass through. If the portal is disposed at the highest elevation then all air escapes when the body is submerged in the liquid and the portal is open..

When the body is filled with liquid the body sinks. When air is pumped through the portal, then the submerged weight, W of the body (W-B) decreases and when buoyancy B exceeds gravity W, B>W (negative submerged weight, W'<0), the structure rises and reaches the level allowed by the tendons. Pumping of air stops when the tendons reach the required tension. At this configuration, the 6 -floor may withstand the imposed load Q without sinking. Lowering of the floor is achieved by opening the portal. The air trapped in the body, being in pressure higher than atmospheric starts moving outside the body and the submerged weight increases. The structure will sink when gravity exceeds buoyancy.

The floor may be separated in a number of individual modules which may be operated independently from each other. For example, one or more modules may be up and others may be down or other intermediate level thus enabling access to the pool under the body.

The apparatus of the present invention has the following advantages: * The floor of the pool may be at surrounding terrain level when the pool is not in use, * The floor may be adjusted at adult or children level or other level for swimming, play, exercise, therapy etc, * The modular characteristics may achieve different depths and different slopes at different areas, * The support surface, being modular, consists of relatively thin structural elements associated with low-cost construction, * The pool may have moving steps and inclined bottom, * The air under the moving floor contributes to achieving warm water in winter and cool water in summer, * When the floor is at the top, there is practically no evaporation and loss of water, * The support surface may be designed to withstand dancing floor load or any other load, * The apparatus may be installed in a new pool or in an existing pool as retrofit, * Changing the level of the support surface may be achieved without the use of mechanical equipment.

Certain embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings.

The apparatus referred to comprises a support in the form of a movable floor and a plurality of tendons.

Figures la and lb illustrate a liquid pool with an inflatable buoyancy body. 7 -

Figures 2a to 2f illustrate the various stages of movement of a rigid buoyancy body with an open bottom surface.

Figures 3a and 3b illustrate how steps in a swimming pool are raised to form a flat deck.

Figures 4a and 4b show a swimming pool with sloping bottom.

Figures 5a and 5b illustrate the support surface at various elevations. Figure 6a shows the forces applied on the support surface, the tendons and the dead weight when the deck is unloaded and figure 6b when the deck is loaded. Figure 7a to 7d illustrate the operation of the automatically closing air release mechanism.

Figures 8a to 8d show an example of how the support surface may be lowered from a high position to a low position.

Figures 9a to 9d illustrate a liquid pool with 20 modules, the modules having various elevations and slopes.

Figure la illustrates an exemplary embodiment with a support having a support surface 110 on the bottom of a swimming pool 10 and figure lb with surface 110 at the same elevation as the surrounding terrain 12. Surface 110 may for example have the same characteristics as the surrounding terrain 12.

The support has a buoyancy body 120 which may be filled with air. The buoyancy body 120 may be part of the same structure as the support surface 110 or a separate body affixed to the structure. In this embodiment, the support having the surface 110 and the buoyancy body 120 form the floor assembly 100. Body 120 in this embodiment is an inflatable one and it has a portal 130 through which air 30 may pass. In figure 1b body 120 is filled with air 30 through portal 130.

Assembly 100 is held at the required elevation, flat with surrounding terrain 12 by tendons 200. Tendons 200 may for example consist of wire ropes, chains or other non-elastic material. Tendons 200 are connected to the bottom to the base of the pool 10, for example to a concrete slab or steel plate. Assembly 100 may sink from raised position of figure lb to low position of figure la by opening portal 130 thus allowing air 30 to escape to the atmosphere.

Figures 2a to 2g illustrate an alternative exemplary embodiment with a rigid buoyancy body 120. Rigid body 120 may for example be a housing made of stainless steel with an open bottom. In this embodiment assembly 100 is raised by pumping air from portals 310 disposed at the bottom of the pool. Air 30, having less 8 -density than the liquid 20, rises and gets trapped inside body 120. Air is prevented from escaping through portal 130.

In figure 2a floor assembly 100 rests over deadweight 300.

In figure 2b air 30 is pumped from portals 310. Air rises and is trapped inside body 120. As the volume of air increases water 20 is displaced from under body 120 and the submerged weight of assembly 100 decreases.

When the buoyancy action, B, exceeds the weight of assembly 100, W, as in figure 2c then assembly 100 starts rising.

Floor assembly keeps rising as in figures 2d and 2e. At the equilibrium position reached in figure 2e the buoyancy action equals the gravity action, B=W.

In all the above figures there is adequate length of tendons 200 so that the tendons are slack.

If the length of tendons 200 is such as to prevent the floor assembly 100 from moving above level 12, as in figure 2f, then the tendons are in tension, T. T=B-W. In this embodiment, tendons 200 are attached to a deadweight 300 disposed on the bottom of pool 10. Dead weight 300 has a submerged weight greater than the maximum uplift force that may be applied on the tendons. Deadweight 300 may for example be concrete having such dimensions that housing 120 may sink and rest on top of deadweight 300, thereby deadweight 310 does not occupy any additional space from the space occupied by housing 120.

Portal 130 is closed when the floor is up. Portal is opened in order to release the air and sink the floor. Portal 130 is closed before air is pumped to raise the floor. Portal 130 may for example be a valve operated for example manually or mechanically or it may be operated by an air release mechanism which closes automatically when air escapes and the surface sinks.

The above embodiment may for example be a retrofit in an existing pool, or a new floor in a pool with membrane base.

The following figures illustrate alternative embodiments with rigid housings 120 and tendons 200 attached to deadweight 300.

Figures 3a and 3b illustrate an embodiment of a swimming pool with steps.

Each step has its own module and corresponding floor and body so that they sink to different elevations, and when up, they are at the same level. In order to prevent movement when people stand on the step module when up, the tension in the tendons of the step module must be larger than the imposed load. The depth of the 9 -bodies of the steps may therefore be deeper than the depth of the bodies for the modules of the deeper parts of the pool.

Figures 4a and 4b illustrate an embodiment of a swimming pool with a sloping bottom floor. In this embodiment assembly 100 is sloped when surface 110 forms the bottom of the pool. Wien air is inside body 120 then assembly 100 is horizontal at the required elevation. This configuration is achieved by providing tendons 200 with different lengths.

Figure 5a illustrates an embodiment in which one module is on the bottom of the pool and another module is at the surface of the water. Such an embodiment is for example used for maintenance or cleaning purposes whereby one needs to access for example the deadweight 300 or the air portals 310.

Figure 5b Illustrates an alternative embodiment with floor assemblies 100 at different elevations. For example, a part of the swimming pool may have depth for children use. Another part may have depth for therapy and other parts depths for other uses.

Figures 6a and 6b illustrate the forces applied on assembly 100, tendons 200 and deadweight 300 when assembly 100 is at the surface. In figure 6a assembly 100 is not loaded and in figure 6b an imposed load Q is applied on assembly 100.

When there is no imposed load, for the vertical force equilibrium of assembly 100: T=B-W100 and for the vertical force equilibrium of deadweight 310: T= W300 When load Q is imposed on assembly 100, for the vertical force equilibrium of assembly 100: T' = B-W100-0 > 0 These forces are referred in the equations described above.

For example, for imposed load of 2 kN/m2 (imposed mass of approximately 200 kg/m2), the required net buoyancy must be larger than 2 kN/m2 and the required submerged weight of the deadweight must be larger than 2 kN/m2. For a module for example with an area of 2m x 2m (4m2) and self-weight of 2kN, the required buoyancy is at least (4m2 x 2 kN/m2+ 2kN=) 10 kN. The depth of the housing must be larger than (10 kN/ (10 kN/m2 x 4m2)) 0.25m, say use 0.30m. The tendons must hold a total force of at least 10 kN. A deadweight, made of concrete, with -10 -dimensions that fit under the housing, 1.9m x 1.9m x 0.22m has submerged weight (1.9m x 1.9m x 0.22m x 14kN/m3=) 11kN, thereby the deadweight does not lift when the deck is unloaded, and the deck does not sink when loaded with 200 kg/m'. Figures 7a to 7d illustrate how for example portal 130 may be opened and closed for release and blockage of air. A buoyant body 132, for example a sphere, is blocking the escape of air when air is under body 120, as in figure 7a. Air portal cover 134 protects closing mechanism 132 from accidental urging downwards. The closing mechanism is a non-return flap valve, which is spring operated and the spring is biased to force the closing mechanism to block the portal to prevent flow of air.

Figure 7b illustrates the first stage for releasing air 30 to escape to the atmosphere. Air portal cover 134 is opened, exposing closing mechanism 132. Air release assembly 400 is brought above closing mechanism 132. Air release mechanism 400 may for example consist of a vertical hollow cylinder with holes around the shell.

When air release mechanism 400 is pressed down on the closing mechanism132 air escapes through the holes on the vertical hollow cylinder. As air 30 escapes buoyancy action on floor assembly 100 decreases and it will start sinking when gravity exceeds buoyancy, as illustrated in figure 7d. As assembly 100 sinks, release assembly 400 stops pushing closing mechanism 132. Closing mechanism closes air portal 130 automatically due to the forces in the spring urging it into the closed position to cover the portal, so that when air is pumped into assembly 100, it may rise.

Figures 8a to 8d illustrate an alternative embodiment for adjusting the length of the tendons 200 manually. In this embodiment floor assembly 100 has triangular recesses at the four corners as illustrated in figure 8a. Tendons 200 have buoyant bodies 220 attached to the top end of each tendon. Tendons have transverse elements 210 preventing the upward movement of floor assembly 100.

When air is released, assembly 100 sinks whereas tendons 200 remain vertical as illustrated in figure 8b. This is achieved by opening covers 150.

Transverse elements 210 are attached at the required location of tendons 200. When air is pumped and assembly 100 moves upwards floor 100 is restrained at the required level as illustrated in figure 8c.

At that position, as illustrated in figure 8d, buoyant bodies 220 are pressed downwards and covers 150 are closed, thereby moving floor 100 is adjusted to the required elevation.

Figures 9a to 9d illustrate an alternative embodiment of a liquid pool with a plurality of modules, in this case twenty modules (four series of 5 modules). In figure 9a all modules are down forming a swimming pool with maximum depth everywhere.

Figure 9b illustrates all modules flat with surrounding terrain, thereby the swimming pool is covered and the support surface may be used as the remaining area, providing a safe for children area.

Figure 9c illustrates the swimming pool with different depths in each row of modules. Such an arrangement may be useful in therapy uses with different groups using different parts of the pool. It may also be used for different children groups with appropriate safety measures.

Figure 9d illustrates how different lengths of tendons in each module may create different pool floor arrangements, as for example different elevations at different parts and sloping floors.

The drawings, details and descriptions of the embodiments are non-limiting ways in which the concepts of the invention may be applied. Their aim is to illustrate to skilled persons the use of the present invention in any appropriate system, method, apparatus, or construction.

Reference in this document to "an embodiment" means that a particular feature, structure, or characteristic is included in at least one embodiment and it does not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in one or more embodiments. Variations may be made within the scope of the invention and parts shown in the drawings or described may be implemented in a more separated or integrated manner or removed or rendered as inoperable. Numerous alternative and different embodiments may be made using concepts of this invention. Drawings, details, and descriptions are interpreted as illustrative and not as limiting the invention.

Claims (16)

1. -12 -CLAIMS 4 8
2. An apparatus for use in a liquid pool comprising a movable support which has a buoyancy body and is configured in use to move between a lower position and an upper position, and the apparatus further comprising a plurality of tendons which in use are configured to connect said support to the bottom of the pool, said buoyancy body being configured to be filled with air, so that when said support is at the lower position in the pool and air enters said body to increase its buoyancy said support rises from said lower position to said upper position to be restrained by said tendons, said tendons being configured to be in tension when said support is at said upper position, and said buoyancy body being configured to have air removed therefrom to cause said support to sink from the upper position to the lower position.
3. An apparatus as claimed in claim 1, wherein said body is configured to be filled with air so that its buoyancy is such that the tendons are in tension when a load of up to 2 kN/m^2 is applied on said support.
4. An apparatus as claimed in claim 1, wherein said body is configured to be filled with air so that its buoyancy is such that the tendons are in tension when a load up to 10kWW2 is applied on said support.
5. An apparatus as claimed in claim 1, wherein said body is configured to be filled with air so that its buoyancy is such that the tendons remain in tension when a load of 0.5 kN/rnA2 is applied to the support.
6. An apparatus as claimed in claim 4, wherein said body is configured to be filled with air so that its buoyancy is such that the tendons remain in tension when a load of 0.5-10 kN/m^2 is applied to the support.
7. An apparatus as claimed in any preceding claim, wherein the upper position is above the liquid level.
8. An apparatus as claimed in any of claims 1 to 5, wherein the upper position is an intermediate position between the bottom of the pool and the liquid level. An apparatus as claimed in any preceding claim, wherein the buoyancy body comprises a means for controlling the rate of flow of air from said buoyancy body.
9. An apparatus as claimed in claim 8, wherein the means for controlling the rate of flow of air comprises a portal through which air may pass, and a closing mechanism configured to prevent the passage of air through said portal.
10. -13 - 10. An apparatus as claimed in claim 9, further comprising an air release mechanism including a hollow body configured to urge the closing mechanism downwards, wherein the hollow body comprises a plurality of apertures for allowing air to travel through said portal.
11. 11. An apparatus as claimed in claim 10, wherein in use the air escapes through said portal of said buoyancy body from the plurality of apertures in the hollow body thereby causing the buoyancy body to fill with liquid and the apparatus to sink, wherein the closing mechanism is configured to be urged upwards to automatically close said portal.
12. 12. An apparatus as claimed in any preceding claim, comprising a dead weight configured to be located on the bottom of said liquid pool, wherein the plurality of tendons are connected to said dead weight.
13. 13. A plurality of apparatuses as claimed in any preceding claim, wherein each support moves independently thereby stepped bottom floors may rise and form a planar top surface.
14. 14. A plurality of apparatuses as claimed in any preceding claim, wherein the pool floor is sloping, and tendons of different lengths configure the movable floor to be sloping when down and flat with grade when up.
15. 15. A plurality of apparatuses as claimed in any preceding claim, wherein each support moves independently.
16. 16. A method of covering a swimming pool with a rigid floor using an apparatus as claimed in any preceding claim.