Field of the Invention

The invention relates to a drainage element comprising a supporting member consisting of internal cells mutually abutting, and outer cells, of which the peripheral walls define the outer walls of the drainage element, which is intended for surface consolidation and water drainage from impermeable or hardly permeable surfaces.

Background of the Invention

Drainage systems are used for drainage of water from various surfaces, most commonly for drainage of water from the soil surface or reinforced surfaces intended to be used as foundations for various building. These surfaces are characterized by various water permeability. Water in the form of rain enters the drainage element through its upper surface and exits through permeable layers of woven or nonwoven material. Excess water in the cell is drained through the passage openings into adjacent cells. The passage opening may be constructed also for drainage of water the cells.

The European application EP2402507 discloses a system for surface drainage of rain water. The system consists of an upper layer, bottom layer, supporting layer and a base layer. The supporting layer is filled with gravel, wherein the rocks adjacent to the base layer have the largest diameter and those adjacent to the base layers have the smallest diameter. The gravel layer with the smallest rocks forms the dividing layer, which divides the supporting layer and the bottom layer. The supporting and the upper layer is provided with lattice reinforcement, wherein the chambers are created. The reinforcement is separated from the road by means of edge strips.

The German application DE3140701 discloses a lattice element with openings and a drainage system, which is intended for grass surfaces. The grid made of flexible and porous material similar to rubber, which serves as a drainage system. The drainage system consists of a set of partitions and chambers for water drainage. The porous material preferably comprises polyurethane-bound granules. The lattice element may be used, for example, in a soccer field goal, wherein the load creates by a foot of a player is substantially absorbed by the lattice and thus protects the plant's root system as well as the plant itself. The French application FR2691726 discloses a device with a drainage layer having smooth surfaces for tennis courts. The drainage layer serves as the base layer. Upon the drainage layer a levelling layer is provided, on which the thermoplastic hexagonal panels, connected mutually as a honeycomb, are arranged. The thermoplastic panels are filled with fine material, mainly red clay of 0 to 3 mm.

The European application EP2687630A1 discloses a drainage element, wherein the bottom part of the walls of each chamber of the drainage element is provided with at least one passage opening, wherein the opening may be positioned in the first half or the first quarter of the chamber wall height. The passage opening allows the movement of water form one chamber into the second. The passage element may be of different sizes or shapes, for example, a quadrangle, a circle, etc. By means of a suitable arrangement of shape and size, it is possible to control the water flow direction. A thin layer of woven or nonwoven material, which helps to drain flow of water downwards and out of the drainage element, may be attached to the bottom edges of the drainage element. The layer also performs a function of a barrier against penetration of plants as well as it maintains the used drainage material in the cell.

The drainage system with geostatic structure and method of production thereof is disclosed in the patent application no. US6505996. The invention is intended to be arranged under the road surface, buildings, retaining walls or parking. Geosynthetic structure formed by geocomposite is preferably provided with permeable geotextile. The drainage system structure allows flow of gases or liquids through the basic element of the structure and permeable foil. The drainage system consists of multiple layers, wherein some of the layers may be attached together by means of ultrasonic welding. The system further comprises another method of drainage of liquid from its structure, for example, by means of a set of perforated tubes draining water from their structure.

Embodiment of the drainage element usually consists of a system of mutually abutting cells divided by walls, which form the passage together with the upper and bottom opening. The cells are often filled with porous material, such as for example soil, gravel or aggregate having different grain size. In case the surface under the drainage element is impermeable or hardly permeable, it may cause uncontrolled overflow of water or washing the filling material out of the cells.

The aim of the invention is to improve water drainage from various surfaces using a drainage element consisting mainly of mutually adjacent cells, which are separated from each other with walls, wherein water permeable foil made of polymer material is ultrasonically welded to the element. Further, the invention aims at providing an inexpensive production method of the drainage element.

Summary of the Invention

The above mentioned drawbacks are eliminated by means of a drainage element, consisting of a supporting member, internal cells and external cells, characterized in that the bottom surface of the internal walls of the internal cells and external walls of the external cells is larger than the upper surface of the internal walls of the internal cells and external walls of the external cells, wherein the bottom surface of the internal cells and external cells of the element is provided with grooves.

The object of the invention is construction of a drainage element, which is filled with drainage material, for example, aggregate with the grain size of 0/36 mm, sand, etc. The drainage element is designed so as to maximize the firmness and at the same time reduce the amount of used drainage material. Reduction of drainage material occurs by mutual fixation of particular aggregate grains in the cells of the drainage element, wherein the walls of the drainage element prevent the movement of aggregate grains out of the inner space of the cell. A geotextile attached on the bottom side of the supporting member of the drainage element separates the aggregate and prevents its movement to bottom layers of the subsoil. Therefore, the bottom layer of the subsoil is not disturbed, which ensures long service life of such treated subsoil. Drainage of water from the cells of the drainage element is ensured by grooves formed on the bottom surfaces of the walls of particular cells. Such a structure of the supporting member of the drainage element provides improved water drainage from the surface of the subsoil, on which the drainage element is applied. A preferred embodiment is a supporting member with dimensions of 1176 mm x 764 mm x 32 m. It consists of interconnected internal and external cells having a hexagonal shape in the plan cross- section. The supporting member preferably consists of 530 interconnected cells, wherein the size of each cell is 42 mm, the width of the upper/bottom surface of the cell wall is 0,8 mm/1 ,4 mm. Water permeable foil is, for example, polypropylene non- woven geotextile with the basic weight of 45 g/m ² -68 g/m ² . This polymer material has high firmness, which results in reduced amount of aggregate in the supporting member. The function of the foil is to separate the used aggregate from the substrate layer and prevents it from mixing with the material of the substrate layer. Thanks to the fact that this non-woven geotextile is flexible, it adapts to the aggregate shape without being damaged.

The depth of the grooves formed on the bottom surfaces of the cell walls of the supporting member is from 0,2 mm to 5 mm, the width is from 0,1 mm to 0,4 mm and the weight of the drainage element without aggregate backfill is from 1 ,3 kg to 1 ,5 kg.

Load capacity of the drainage element, which consists of non-recyclable polypropylene, is 120 T/m ² without a backfill, and the load capacity while using recyclable polypropylene is 95 T/m ² , loading capacity of the drainage element with backfill, while using non-recyclable polypropylene, is up to 300 T/m ² , and load capacity of the drainage element while using recyclable polypropylene is up to 250 T/m ² , thermal restriction of the drainage element is from - 20 °C to +70 °C.

Another part of the scope of the invention is a method of production of the drainage element characterized in that the drainage element is positioned on the permeable foil with its bottom surface of the internal cells and the external cells, after which a firm connection between them is formed by means of downforce and ultrasonic vibrations in a direction perpendicular to the plane of the bottom surfaces which are being connected, wherein, at the same, grooves are formed on the bottom surface of the internal and the external cells.

Ultrasonic welding refers to a method of formation of a firm connection between materials, which utilizes oscillating ultrasonic energies in the connected regions. Materials are welded as soon as a suitable static force is present in the welded regions, which ensures acoustic coupling, while using ultrasonic vibrations in a direction perpendicular to the plane of the connected surfaces. In ultrasonic welding of plastic, the connection is formed by vertical action of the ultrasonic vibrations on the plane of the connection, while at the same time using the action of pressing force. By means of heat generated by friction in the contact regions, or absorption of the ultrasonic energy in the welding region of the materials, softening occurs first and the melting follows. The pressing force is still maintained after completion of the ultrasonic vibrations, so as the connection is transformed from the plastic into solid state. In this way, the grooves-channels formed on the bottom surfaces of the cells walls are preserved. The overall welding time is short, even considering both operations, and usually does not exceed 2 to 3 s.

The drainage element produced using the method according to the invention allows redistribution of water into surroundings, maximization of its firmness and reduction of the aggregate amount in the drainage element, which, thanks to its lightweight structure, also allows secure application, for example, even on the roofs of the houses or terraces. Provided that it is used by a professional, it provides stable and porous surface.

Brief Description of the Drawings

The invention will be further described by means of drawings, in which the fig. 1 illustrates axonometric view of the drainage element provided with permeable foil, Fig. 2 illustrates axonometric view on the drainage element from the bottom, fig. 3 illustrates a view on the B detail of the cells of the supporting member from the bottom, Fig. 4 illustrates a view on the C detail of the set of grooves formed on the bottom side of the cells, Fig. 5 illustrates a cross-section of the drainage element in the section A-A, fig. 6 illustrates a view on the B detail of the cell of the supporting member from the top, Fig. 7 illustrates the shape of the sonotrodes, fig. 8 illustrates the arrangement of the ironing table having a plurality of sonotrodes in ultrasonic welding of the permeable foil and the plastic moulding, and the fig. 9 illustrates the mutual arrangement of the particular parts of the drainage element, wherein the particular cells are filled with aggregate.

Description of the Invention

The invention relates to a drainage element, which will be further disclosed by means of a preferable embodiment, which it not limiting regarding the scope of the invention.

The exemplary embodiment of the drainage element 2 is illustrated in the fig. 1 and fig. 2. In this embodiment, the drainage element consists of the supporting member 1 firmly connected with the permeable foil 4. The supporting member ± consists of the internal cells 3, which are surrounded by the adjacent internal cells 3, and on the edge of the supporting member by the external cells 3^. The internal cells 3 as well as the external cells 3^ may be of hexagonal, pentagonal, rectangular, triangular shape or other similar shape, in the plane cross-sectional view. All the internal cells 3 as well as the external cells 3 ^' are mutually interconnected by means of their walls 5, see the fig. 3. In case that the internal cells 3 and the external cells 3 ^' have a hexagonal shape in their cross-section, they are arranged in a shape similar to a honeycomb. It is not a requirement for all the internal and external cells 3 and in the supporting member Λ to have the same shape and size, as the height and width of the internal and external walls 5 and ( as well as the shape of internal and external cells 3 and 3 ^' are determined by the specific requirements on the structure of the drainage element 2, wherein these requirements are determined by the place of application of the drainage element 2. The internal cell 3 consists of walls 5, which may be arranged in a hexagonal shape, and thus define its inner space as well as the inlet 9 (fig. 1 and fig. 5), through which the aggregate 12 is supplied to the cell 3 of the drainage element 2, as it is apparent from the fig. 9. Further, the openings 9 formed in the internal as well as external walls 3 and 3 ^' are used for entry and passage of water through the aggregate 12 and the permeable foil 4 to the subsoil 13. The walls 5 and ί of the internal as well as the external cells 3 and 3 ^' are characterized by different width on the bottom surface 6 and the upper surface 7, see the fig. 6. Difference of the width of the walls 5 of the internal and the external cells 3 and 3 ^' ensures high surface load of the supporting member. Regarding the fact that the drainage element 2 without the grooves 8 is not able to drain water from the particular internal and external cells 3 and 3 ^' effectively, the bottom surfaces 6 are therefore provided with the grooves 8, see the fig. 5. The grooves 8 serve to drain water from the particular cells out of the inner space of the supporting member 1. The supporting member 1 of the drainage element 2 is connected with the permeable foil 4, which helps to drain water downwards and sideways, wherein at the same time it serves as a barrier against penetration of plants. In this way, it is possible to prevent washing out of the filling material by water, which would flow through the upper opening 9. Method for the production of the drainage element 2 consists of the following steps. The drainage element 2 is positioned on the permeable foil 4 with its bottom surface 6 of the internal cells 3 and the external cells 3', wherein using pressing force and ultrasonic vibrations at the same time, in a direction perpendicular to the plane of the connected bottom surface 6, a firm connection between them is formed, wherein at the same time the grooves 8 are formed on the bottom surfaces 6 of the internal cells 3 and the external cells 3^.

Production of the drainage element 2 according to the claimed method is as follows. Using an ultrasonic device, the supporting member 1j in a form of a plastic moulding, and the permeable foil 4 in the form of permeable non-woven geotextile are connected together. Ultrasonic device consists of ultrasonic ironing table 10, which is provided with a plurality of sonotrodes H having shaped surface, as it is apparent for example in the fig. 7 and fig. 8. The ultrasonic welding is performed as follows. The supporting member 1, e.g. plastic moulding, is arranged on the ironing table so as the wider bottom surfaces 6 of the internal and external walls 5 and 5 ^' of the moulding are positioned at the top. The traction element of the chain has to fit into the internal and external cells 3 and 3 ^' in order to provide secure movement of the supporting member 1, in a form of a moulding, across the table. In the upper part of the ultrasonic table, the permeable foil 4, e.g. non-woven geotextile, has to be installed, so as to evenly unfold during the movement of the supporting member 1 across the table. The permeable foil 4 has to be stretched and threaded under the sonotrodes 11. in order to form a firm connection between the bottom surfaces 6 and the permeable foil 4 by means of pressing force of the sonotrodes 11.. At the same time, ultrasonic vibrations have to be used in a direction perpendicular to the plane of the connected bottom surfaces 6 of the internal and the external walls 5 and 5 ^' of the internal and the external cells 3 and 3 ^' . In this way, the grooves 8 are formed on the bottom surfaces 6, wherein its shape copies the shaped surface of the sonotrodes 11. The number of grooves depends on the shape of the sonotrodes H, i.e. in case the maximum width of the foot of the protrusions 14 is 11 ,2 mm, the number of grooves 8 is four, in the direction perpendicular to each bottom surface 6 of the internal and the external wall 5 and 5 ^' . In case the minimal width of the foot of the protrusion is 1 mm, the number of grooves 8 is forty-four, in a direction perpendicular to each bottom surface 6 of the internal and the external wall 5 and IT. At least four internal and the external walls 5 and 5 ^' of the internal and the external cell 3 and 3 ^' are provided with grooves 8 for water redistribution, wherein the grooves 8 are oriented transversely, under the 30° angle, relative to the internal and the external walls 5 and 5\

The invention is not limited to the embodiment described in the patent application, wherein the drainage element 2 may be produced in different variations within the scope of the respective claims. For example, the plan cross-section of the internal and the external cells 3 and 3 ^' is not limited in its shape illustrated in the drawings, and these cells 3 and 3 ^' in the supporting member Λ may be of rectangular, pentagonal, etc. shape in their plane cross-section. The grooves 8 may also be specifically adapted for each bottom surface 6 of the internal and the external cells 3 and y, for directing the water flow. Such shaping of the grooves 8 is dependent on the surface of the sonotrodes 11.

Industrial Applicability

The drainage element may be used for gravel, sand or soil. It is designed so as to maximize the firmness and at the same time reduce the amount of the used aggregate. The drainage element may be arranged on a road or a structure, such as roof of a building, terrace, etc., and it is used for drainage of, for example, rain water from the surface into surroundings.

List of Reference Signs

1 supporting member

2 drainage element

3 internal cell

3 ^' outer cell

4 permeable foil

5 internal cell wall

5 ^' external cell wall

6 bottom surface of the cell wall

7 upper surface of the cell wall

8 grooves

9 upper opening

10 ironing table

11 sonotrode

12 aggregate

13 subsoil

14 sonotrode protrusions