The subject of the invention is the way of making the swimming pool basins or other tanks.

Swimming pool basins made by means of various technologies are known. Currently, the following solutions are applied:

- Basins made of reinforced concrete with ceramic covering,

- Basins made of reinforced concrete painted from the inside,

- Basins made of reinforced concrete covered with PVC liner,

- Composite basins made of polyester lamination,

- Basins made of polypropylene,

- Panel basins made of stainless steel, screwed and covered with PVC liner or coated with ceramic facing,

- Basins with an uniform construction made of stainless steel, welded, without additional coatings,

- Panel basins made of galvanized steel screwed and covered with PVC liner,

- Panel basins made of various plastics, covered with PVC liner,

- Basins made of treated wood, covered with PVC liner.

Within the scope of tanks for other purposes generally are applied the following solutions:

- Tanks made of reinforced concrete,

- Tanks made of various plastics,

- Tanks made of non-ferrous metals,

- Tanks made of structural and alloy steel.

The most similar solution is swimming pool basins or tanks made completely, together with a stiffener, of stainless steel. Planking appears only from the inner side of a tank and is made of stainless steel. Tightness is gained thanks to welding of prefabricated elements at the installation site. The ribbing is directly connected with planking by means of a welding technique or indirectly with a combination based on welding the ribbing elements to previously fastened for planking, with a technique of pressure welding of pins. Outer planking is not applied. With the aim of gaining thermal insulation pasting with insulation materials is applied. Whereas with the aim of gaining rust proofing, a foil coating (e.g. Myrtha system) or oil film is applied. Moreover, with the aim of limitation of the rust effect of the outer surrounding special technical requirements regarding the environment are defined, in which a basin or a tank should be found. In case of swimming pool basins with upper overflow to a perimeter gutter, additionally muffling of noises is applied, with is obtained with a help of elements dispersing a stream of water in the area of outflow from a gutter.

Principally the technology of making swimming pool basins completely from stainless steel stands out of from the others with a high resistance to the influence of mechanical, biological or atmospheric factors on the inner side during operation according with its purpose. Furthermore, it is characterized by lightness of construction, complete tightness, high resistance to tectonic movements, easiness of location of potential leakage of welds and their repair. Nevertheless stainless steel, from which the construction of swimming pool basins is made, is characterized by high heat transfer coefficient. What is more, one cannot guarantee the resistance to corrosion influence of the outside environment.

Basins made of reinforced concrete are characterized by a slightly lower cost of workmanship, better thermal and acoustic insulating and are more resistant to degradation from the outside. Inner facing, i.e. ceramics, paint cover or liner are characterized by significantly lower resistance than stainless steel, particularly to mechanical, atmospheric and biological factors.

Plastic or wooden basins covered with PVC liner from the inside are characterized by a good thermal and acoustic insulating, quite good resistance to external factors, whereas because of the application of PVC liner covering with the aim of gaining tightness, they are sensitive to the influence of mechanical, atmospheric and biological factors from the inside.

Panel basins can be made both of stainless or galvanized steel, are screwed and covered with PVC liner from the inside, are relatively easy in installation and light. Nevertheless, they have a high heat transfer coefficient, whereas the result of applying PVC liner as the inside covering are as sensitive to mechanical, atmospheric and biological factors as in the other cases of its application.

All currently applied technologies do not provide at the same time:

1 . Total tightness,

2. High hygienic appropriateness thanks to the application of aseptic material for making the inside planking,

3. High resistance to mechanical, atmospheric and biological factors from the inside,

4. High thermal and acoustic insulating,

5. High resistance to the influence of surrounding factors on the outer surface of a swimming pool basin or a tank.

The essence of solution is based on a proper defining of the functions for stainless steel and plastic as the materials used for construction of swimming pool basins and other tanks and working out an optimal way of combining these materials.

Basically, the tanks are the subject of two kinds of influences, i.e. the influence on the inner and outer surface. From the inside the surface of a tank is influenced by occurring liquid there and living organisms, whereas from the outside the surrounding in which a tank is located. Inner influence can be to a large extent controlled, but the outer control is considerably limited.

The technical problem, particularly in case of swimming pools, is keeping the highest resistance to both kinds of factors at the same time. The practice shows that stainless steel, thanks to the possibility of controlling the physical and chemical parameters of the liquid inside the tank is almost perfectly resistant to inner factors, additionally has aseptic properties, preventing the growth of bacteria and microorganisms on the surface. Whereas, the outcome of changeability of the outer surrounding's parameters and a lack of control over them, particularly in high probability of appearing chlorine, what takes place in pool branch, stainless steel is exposed to uncontrolled degradation being the result of chlorine and other chemical substances commonly occurring in the surrounding . A much higher resistance to the impact of chlorine and other chemicals commonly exist in the environment have a plastics. The swimming pool basin, according to the invention, is characterized by the fact that the wall of the basin is composed of two types of material, i.e. stainless steel as the inner sheathing and substructure mounting elements and plastic performing the functions of the ribbings and the outer shell of the swimming pool's wall.

It is therefore preferable when the connection of structure elements made of plastic with stainless steel sheathing and the support profile of the wall is made by a screw connection with threaded studs previously fixed to the stainless steel sheathing and the supporting profile by means of butt welding technique. It is therefore preferable when the carrier units and plastic ribbing are made of flat elements shaped in such a way as to allow configuration, performing a structure that locks itself under load made using the tongue-and-groove technique, permanently joint by means of structural adhesive or welding the plastics.

It is therefore preferable when the outer sheathing made of plastic is based on the plastic ribs of the swimming pool basin's walls.

It is therefore preferable when individual, prefabricated walls of which the swimming pool basin's corps is made are then suspended in at least four points, i.e. two at the ends of supporting profiles (14) via threaded studs (12) to the fixing profiles (1 1 ), whereas the profiles (1 1 ) are connected to the base by welding to the mounting plates (15) anchored in the foundation. And the supporting profiles (14) are based on adjusting nuts (13).

As per the invention, stainless steel that has been applied in the swimming pool basin has then the function of the inner surface of basins and tanks. It is the material directed to contact with water or other liquids contained in the swimming pool basins or tanks. In this way the advantage of stainless steel as aseptic material is completely fulfilled. On the other hand, the plastic is applied as material fulfilling other functions of the tank's construction, i.e. construction function (stiffing) and insulation (stiffing + outer sheathing). Whereas, the insulating function refers to three areas:

® Thermal insulating, particularly favorable because of high thermal resistance of hermetic air gap between the inner (stainless steel) and outer (plastic) sheathing. The application of stiffing from plastic minimizes the effect of thermal bridges.

« Chemical insulating obtained thanks to application of outer sheathing from plastic, which is an effective barrier protecting stainless metal sheet of inner sheathing against aggressive influence of the outside surrounding.

® Acoustic insulation resulting from high abilities of muffling vibrations, which are the characteristics of plastics from which is made load bearing structure of the basin.

There is also fastening of walls to foundation and the screw adjustment system made with stainless steel. Although these elements are found on the outer side of a basin, they are also protected from the corrosion influence of the surrounding, with regard to the fact, that they are purposed for concreting.

Such solution ensures obtaining a range of benefits appearing at the same time in application of possibly the simplest means, i.e. construction elements made only of two kinds of materials, connected by simple techniques, where the most expensive of these is a SAW technique, limited in this solution to essential minimum.

A tank built this way and particularly swimming pool basin is characterized at the same time by the following advantages:

- It is aseptic, resistant to growth of microorganisms inside.

- It is characterized by smooth and an esthetic inner surface, what has a particular meaning in case of swimming pool basins as the significant elements of architecture.

- It is completely tight, thanks to connections of inner sheathing elements of each wall with a welding method (SAW).

- It is structurally self-bearing.

- It has effective thermal insulation. - It is resistant to the influence of most of the aggressive factors of the surroundings, to which the stainless steel itself can be sensitive, what generates the following additional benefits:

• It is practically non-service, i.e. it does not require a regular technical inspections, additional anticorrosion protection, special care or other special maintenance,

• In case of swimming pool basins externally exposed to aggressive atmosphere in technical room does not require application of special, additional technical means limiting corrosion influence of the surroundings.

• In case if swimming pool basins deepened in the ground there is eliminated a serious risk of appearing corrosion from the side of the ground being the result of the influence of aggressive substances for stainless steel, which can penetrate directly into the basin's neighborhood.

- It is quiet what has a particular meaning in case of swimming pool basins with upper overflow to circular gutter.

- It is a light construction, what enables to put the basins or other tanks made with this method on higher levels, without the necessity of applying special solutions. Undoubtedly, significant chief assets with such application are also the highest insulation properties within the thermal and acoustic scope.

Thanks to the use of the best qualities of stainless steel and plastic at the same time guarantees the highest durability and resistance to environmental impacts which translates to obtain the lowest operating costs compared to swimming pool basins made in another way.

The example of the invention's realization have been presented on the drawings, where:

Fig. 1 , Fig. 2, Fig.3, Fig. 4 and Fig. 5 present the elements of the swimming pool basin assembly. The wall of the basin is a type of stressed skin construction from stainless steel and plastic. The solution takes into account making straight and curved walls. The system consists of inner sheathing 2 made with stainless steel, bearing elements 1, 14 and stiffing 5 as well as the elements of outer sheathing 3. The construction is fully self-bearing. Water pressure is transferred by the carrier units 1 to the base of the wall fixed in the concrete base 10. The whole construction, together with stainless steel sheathing 2 makes a ribbed surface structure. The stainless steel sheathing elements are connected with supporting plastic construction via stainless steel threaded pins 9, welded to surface of stainless steel sheathing 2 with a capacitor or arc butt fusion jointing. Pins are threaded, what enables to join the stainless steel sheathing with plastic construction elements using screw connection (Fig.1 pos. 6, Fig.2 pos. 8, 9). Additionally, the steel-plastic connection can be strengthened with a specialist adhesive for connecting stainless steel with plastic.

Carrier units and stiffing are made of flat elements cut out from plastic plates and then they are permanently connected with a tongue and groove method and structural adhesive.

With the aim of obtaining a closing from the outside for the ribbing, the carrier profiles and stiffing are shaped in such a way to attach the outer plastic sheathing elements 3 in an easy way. These can be attached to the construction with rivets or alternatively with screws. The connecting of outer sheathing 3 with carrier units 1 are additionally tightened using adhesives, tightening mass or plastic welding technique. Its aim is to ensure hermetic seal of air gap 4 between steel and plastic sheathing.

Swimming pool basin as a whole is assembled at the installation site through precise adjustment of prefabricated walls and then connecting them from the inside using a SAW technique to join stainless steel sheathing 2. The filling of the outer sheathing in connecting places of the walls is performed through fastening plastic supplementary elements in an analogical way to the prefabrication process. This way the uniform, continuous outer sheathing of a basin is obtained.

Thanks to the appropriate configuration, there is a possibility to place in the space between the inner and outer shell of any instrumentation such as ladders in a niche, attractions, hydraulic components and underwater lighting. Carrier units 1_transfer the load on the supporting profiles of stainless steel(14). On the one wall are foreseen two supporting profiles 14. They are suspended by means of hangers composed of a short u-profiles of stainless steel 1_1 and a welded in, threaded rod Υλ. These hangers after proper wall adjustment in the surface of the basin's corps are welded to a fastening plates 5 previously anchored in the concrete base 10 by anchors 16. Regulation nuts 13 after the right matching of a wall are blocked by welding them together with a threaded rod of the hanger 1 The application of a combination of regulation nut and the threaded rod 13, 12 enables a safe and precise regulation of the wall's position in two remaining surfaces i.e. vertically and horizontally. This solution lets to gain in a safe way a very precise adjustment of the walls in the horizontal and vertical surface, what has a particular meaning in case of swimming pool basins with upper overflow, where keeping of the overflow rim on a constant level along the whole perimeter is crucial.

In order to stiffen of the fixing between the walls and concrete base the concreting 17 of this zone is applied.

The example given above does not present all possibilities of this invention.