Technical field

The invention relates to an adjustable pool floor with the function of a walkable thermally insulating surface cover.

State of the art

The market already offers solutions of a height-adjustable pool floor (hereinafter "adjustable floors" or "floors"), based on European Patent EP 2002072, which allow to raise and lower the pool floor by means of high- pressure hydraulic pistons, embedded in recesses formed in the bottom of the pool.

Applications were also filed and patents and utility models granted for various lifting mechanism alternatives, based on a buoyant force induced by injecting air into tanks or bags under the adjustable pool floor or using the principle of a chain drive, helices or a mechanical scissor lift.

Most of the solutions known at present require a special design of the pool body, which prevents their installation in existing pools and increases the costs of new-built pools so that they become unavailable for home use. Solutions using compressed air need compressors to operate, which entails additional costs and noise, and they cause variable water surface level and, most importantly, do not provide sufficient stability for uneven load, for example when more persons step on the edge of the adjustable floor in its surface position. None of the solutions known so far addresses the design of the thermal and evaporation insulation of the feed opening and the frost resistance of the peripheral joint.

Basic of the invention

The deficiencies mentioned above are, to a large extent, eliminated by a height-adjustable pool floor, adjustable to any depth from the pool bottom to the water surface, where it can serve as a walkable, thermally insulating and evaporation-proof cover of the pool surface, as specified in this invention. Its essence is that it is fitted with at least two evenly spaced lifting bags at the bottom, attached to the pool bottom and the height-adjustable pool floor and connected to a pump that fills them with pool water; the pool floor is provided with at least one feed opening.

Advantageously, seating spacer blocks are placed at the pool bottom and/or the underside of the pool floor to protect empty lifting bags against damage.

Advantageously, the height-adjustable pool floor consists of a moulding with embedded thermal insulator covered by a monolithic support plate on which a waterproof floor covering and/or coating is applied.

The height-adjustable pool floor can be also made up of at least two parallel plates, hermetically fixed to at least one layer of a supporting trellis structure of I-profiles that together create cavities filled with air and/or other thermal insulator in the space between; a floor covering or coating is placed on the upper plate.

The part of the side wall of the height-adjustable floor of the pool that remains submerged even in the upper position of the floor is advantageously bevelled to ensure a sliding movement of the created ice block in the direction of the space under the thermally insulated height- adjustable floor in case the peripheral joint between the walls of the pool body and the adjustable floor freezes.

Advantageously, a peripheral rim composed of replaceable elastic peripheral sealing installed in a U-profile groove is placed on the side wall of the height-adjustable floor above the pool water surface when the height-adjustable floor is in its upper limit position.

The lifting bags can be connected to a hydraulic distribution system, fitted with multiway control servo valves and/or governor throttle valves to balance the even filling of the lifting bags. The pump used for counter- current swimming can be also used to fill the lifting bags with pool water.

The lower part of the walls of the feed opening, which remains submerged even in the upper limit position of the height-adjustable floor, is advantageously bevelled for a sliding movement of the created ice block in the direction under the feed opening in case the feed opening freezes.

The cover of the feed opening of the height-adjustable floor can be made from a support tube with an integrated walkable grid, containing an assembly of rotating segment shutters in the inner bottom part to ensure thermal insulation and limit the evaporation of pool water when the height-adjustable floor is in its upper limit position.

The cover of the feed opening of the height-adjustable floor can be also fitted with segment shutters with eccentrically installed pins/shafts to ensure the correct direction of rotation of the segment shutters back into the horizontal position. To ensure the proper direction of rotation of the segment shutters back into their horizontal position, the cover of the feed opening of the height- adjustable floor can be composed of segment shutters with springs, anchored on one side in the shutter and on the other side in the peripheral tube so that the springs are in a rest position, i.e. with a zero torque when the shutter is in its horizontal position.

The present technical solution of an adjustable pool floor is characterized by the following parameters:

The lifting mechanism employs low-pressure bags made of a reasonably elastic waterproof material, such as rubberized fabric or nylon fabric coated with plasticized PVC etc., filled with pool water by means of a pump with a sufficient flow rate, such as the pool filtration pump or the counter-current swimming pump. Lifting bags are evenly distributed over the area of the pool; 3 bags are usually enough for a circular pool and 4 bags for a rectangular pool. The lifting bags can be of any shape, for example cylindrical; their base area is selected according to the user- desired load and speed of movement of the adjustable floor and based on the parameters of the selected pump. The lifting bags are securely fastened with their lower base to the bottom of the pool and with their upper base to the adjustable floor. In the lowermost position of the adjustable floor, the empty bags are compressed into the gap between the floor and the bottom of the pool, while the adjustable floor is seated on special-purpose spacer blocks designed to prevent mechanical damage to the bags in the space between. The fully filled bags raise the upper surface of the floor above the water surface, creating a thermally insulating, walkable cover of the pool. By filling the bags only partially it is possible to set the depth of the floor according to the current needs of the users. The adjustable floor has to be sufficiently strong to carry the load of the user-defined number of persons in its water-surface position and, at the same time, it has to be resistant to the effects of pool water, including chemicals added to it. These requirements are fulfilled for example by a massive reinforced concrete slab with embedded thermal insulation of extruded polystyrene or another insulating material with similar properties.

The floor can be also designed as a sandwich structure of the commonly used pool plastics, such as polypropylene, or composite materials, such as fibreglass; in that case, thermal insulation is provided by structural cavities in the grid space between the upper and the lower plates, filled with air or another thermally insulating material.

A waterproof surface layer with a no-slip design selected by the user, such as a suitable flooring, plaster or paint matching the poolside finish, can be then installed on this adjustable floor structure.

Along its perimeter, the adjustable floor is fringed with an elastic rim, preventing its horizontal motion and the related wear and tear of the pool body walls. This peripheral seal also serves as thermal insulation of the peripheral joint.

If, nevertheless, this least-insulated part freezes on outdoor pools during prolonged heavy frosts, the created ice is pushed to the space underneath the floor, thanks to the bevel of the submerged side section of the floor, where it would not damage the structure of the pool or its adjustable floors.

For maximum efficiency of the peripheral seal of the adjustable floor, all penetrations through the pool walls, i.e. skimmer, nozzles, drains, lighting fixtures, etc., are recessed so as not to protrude from the profile of the peripheral walls into the pool.

Position sensors, either magnetic, optical, electromechanical or other, are installed at least in the upper and lower sections of the pool and the adjustable floor to signal the limit positions of the floor, i.e. on the water surface and at the bottom, as well as any other positions in between.

The position of the feed opening in the adjustable floor is dimensioned to make sure that the flow capacity of the feed opening allows the adjustable floor to reach the selected speed of movement in water, taking into account the parameters of the lifting mechanism, i.e. the speed of filling and emptying the lifting bags, all of this with consideration of additional resistance posed by the cover installed in the feed opening.

Since this opening is also used as an access hole for installation and service work under the floor, its size always has to accommodate at least the passage of one person, along with tools and spare parts.

To ensure thermally insulating and anti-evaporation functions, the cover of the feed opening is designed to close by means of the segment shutters when the floor reaches its water surface position and, at the same time, to allow water passage if the floor is to move.

The wall of the feed opening is bevelled at the bottom for the same reasons as the peripheral wall of the adjustable floor.

The direction of floor movement is controlled by means of multiway servo valves and the even filling of the lifting bags is balanced by governor throttle valves. The user can use a keyboard panel and/or a wireless remote controller for control. Ideally, when the counter-current swimming pump is used for filling, the pump is integrated in the hydraulic distribution system and the control logic so that the user could use the pump's counter-current swimming function when the floor is positioned on the bottom o the pool.

Drawings explanation

Figure 1 shows an embodiment of the low-pressure hydraulic lifting mechanism. Figure 2 illustrates an embodiment of the side wall of the adjustable floor, including the elastic peripheral seal, and an embodiment of the massive structure of the adjustable floor. Figure 3 illustrates an embodiment of the sandwich structure of the adjustable floor. Figure 4 shows an embodiment of the feed opening with a cover, allowing a high bidirectional flow rate through the feed opening. Figure 5 shows an embodiment of a more efficient cover of the feed opening suitable for a low flow rate when the adjustable floor is being raised. Figure 6 illustrates an embodiment of the nozzle recess in the wall of the pool body.

Embodiments of the invention

The low-pressure hydraulic lifting mechanism shown in Figure 1 consists of lifting bags 1, each filled and emptied through the neck 2 and firmly attached to the bottom of the pool and to the adjustable floor 3. In the adjustable floor 3 there is at least one feed opening 4 that is also used as a service access into the area under the adjustable floor 3. At the bottom of the pool and/or on the underside of the adjustable floor 3 there are seating spacer blocks 5 that protect the empty, compressed lifting bags 1 against damage due to the weight of the adjustable floor 3 at the bottom of the pool. An embodiment of the side wall and the elastic peripheral seal 6 of the adjustable floor 3 is shown in Figure 2. For the purpose of replacement, the elastic peripheral seal 6 is installed in a U-profile groove 7. Part 8 of the side wall of the adjustable floor 3, which remains under water even in its upper limit position, is bevelled so that if the peripheral joint freezes, the created ice block slides in the direction of the space under the thermally insulated adjustable floor 3. Figure 2 also shows an embodiment of the massive structure of the adjustable floor 3. A suitable insulating material 9, for example extruded floor polystyrene, is placed in the mould 9, for example made of pool plastics, metals or composite materials; the support plate 11 of the adjustable floor 3, for example made of reinforced concrete, is then laid on it. The upper surface of the adjustable floor 3 is fitted with a suitable floor covering 12, preferably of the same type as is used in the immediate vicinity of the pool body, such as non-absorbent tiles with a non-slip surface.

The design of the sandwich structure of the adjustable floor 3 is shown in Figure 3. In this case the floor 3 consists of two or more plates 13, for example made from pool plastics, metals or composite materials, fixed to the supporting trellis structure of I-profiles 14. The air chambers generated in the interim spaces 15 have a thermally insulating function, which can be enhanced by inserting a special thermally insulating material. The lightweight sandwich structure is covered with a floor covering 12 with similar characteristics as those specified for the massive adjustable floor 3.

The design of the feed opening and its cover is shown in Figure 4. The bottom section 21 of the feed opening walls, which remains under the water surface even when the adjustable floor is in its upper limit position, is bevelled, similarly to the side wall of the adjustable wall 3; in case the feed opening freezes, this ensures a sliding movement of the ice block under the feed opening. A supporting tube 16, for example made of stainless steel or durable plastics, is inserted into the perimeter of the feed opening from the top; a walkable grid is attached to its upper section 17. An assembly of segment shutters 18 of a lightweight, waterproof, thermally insulating material, for example extruded polystyrene, is installed in the bottom section of the tube 18; when the adjustable floor 3 is in its upper limit position, these shutters are aligned horizontally on the surface and serve for thermal insulation purposes and to curb significantly water evaporation from the pool. When the floor 3 moves under the water surface, the shutters 18 turn automatically to allow water flow. To ensure the proper direction of movement of the shutters 18 back to their horizontal position on the surface, the pins or shafts 19 about which the shutters 18 rotate are positioned eccentrically so that centre of gravity of the shutters 18 in their vertical position ensures the desirable direction of rotation. There are backstops 18 in the tube 16 to prevent the shutters 20 from turning in the other direction. A proper distribution of the segment shutters 18 on the water surface can be also ensured by means of coil springs, anchored at one end to the segment shutter 18 and at the other end to the peripheral tube 16, so that the springs have a rest position, i.e. zero torque when the shutter 18 is in its horizontal position.

When the flow rate is too low, i.e. a larger size of the feed opening and/or a lower speed of movement of the floor 3 is selected, and the flowing water does not rotate the segment shutters 18 downward even if the floor 3 moves up, the assembly of segment shutters 18 of the feed opening cover as shown in Figure 5 can be advantageously chosen. The overlap of the segments on the shutter 18 in the upper limit position of the adjustable floor 3 increases the efficiency of their thermally insulating and anti-evaporation functions. The segments can be even placed under water in this case. The created air pocket provides additional thermal insulation and, in addition, this solution does not result in the need for installation of -loan automatic level sensor or frequent manual discharge of water from the pool since the thermally insulating and anti-evaporation functions of the segments are preserved regardless of any drop in the pool level.

An embodiment of the recessed wall nozzle is shown in Figure 6. The neck of the nozzle 22 that leads to the pool is recessed into a hole in the pool wall 23 so that it does not protrude beyond the internal profile of the pool wall. The body of the nozzle 22 is anchored in the material 24 attached (glued or welded) to the outer side of the pool wall.

Industrial Applicability

The invention makes adjustable pool floors available to a larger group of users, including users of family pools, both in terms of lower acquisition costs and their usability in harsher climatic conditions.