| to possible su bmerged vegetations. In practice, the equipment ampl ifies a natural process, cooperating with the nature of the sea state. Another advantage of the method and of the equipment is given by the fact that the qualitative features of the catchment water are such as to considerably lower the costs for the pre-treatment of the caught waters and for the maintenance of the treatment system. A further advantage of the method and of the equipment in hand is constituted by its constructive and functional simplicity and as a consequence by the low costs for management and maintenance. In practice, the embodiment of the invention, the materials used, as well as the shape and dimensions, may vary depending on the requirements. Should the technical characteristics mentioned in each claim be followed by reference signs, such reference signs were included strictly with the aim of enhancing the understanding the claims and hence they shall not be deemed restrictive in any manner whatsoever on the scope of each element identified for exemplifying purposes by such reference signs. Claims 1 ) Method for catching seawater, characterized in that it comprises the steps of a. realizing an excavation along the swash zone line of a sandy shore (2), at a defined depth under the sea level (L); b. introducing, at the bottom of said excavation, a collection tank (1 0) of the drained waters presenting an opening in the upper part; c. closing said upper opening of said collection tank (1 0) through at least a filtering element (15), consisting of a fabric tubular member suitable to be filled with inert filtering material; d . steadily fastening said filtering member (1 5) to said collection tank (1 0) through support means (13,14); e. burying said collection tank (10) to drain inside it a flux of seawater conveyed on shore by the sea state, exploiting the gravity filtration motion through said sandy shore (2); f. evacuating the water collected in said tank (10). 2) Equipment for catching seawater, characterized in that it comprises a collection tank (10) of the drained waters presenting an opening in the upper part and suitable to be introduced at the bottom of an excavation realized along the swash zone line of a sandy shore (2), at a defined depth under the sea level (L); a filtering member (15) suitable to be arranged as closure of said upper opening of the collection tank (10) and consisting of a fabric tubular element suitable to be filled with inert filtering material; support means (13, 14) of said filtering member (15) suitable to steadily fasten the same filtering element (15) to said collection tank (10). 3) Equipment according to claim 2, characterized in that said collection tank (10) consists of a series of reinforced concrete pools (1 1 ), arranged in-line and modularly connected to each other. 4) Equipment according to claim 2, characterized in that said tubular member (1 5) is made of biaxial fabric consisting of fibrillated filaments in black polypropylene fibre. 5) Equipment according to claim 2, characterized in that said inert material consists of fine gravel with coarse sand, containing 98% quartz. 6) Equipment according to claim 2, characterized in that said support means (13, 14) comprise a draining cushion (14) formed by a draining core consisting of a three-dimensional woven roving with cusp-shaped structure consisting of monofilament yarns of polypropylene heat-welded in the contact points. 7) Equipment according to claim 6, characterized in that said draining woven roving is thermally coupled in the upper part to a layer of textile with the function of separation and filtration. 8) Equipment according to claim 3, characterized in that said support means (13, 14) comprise a series of steel transversal plates (13), fixed at the top part of said pools (1 1 ) regularly spaced from one another. |
METHOD AND PLANT FOR CATCHING SEAWATER
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Technical Field
The present invention regards a method and an equipment for the catchment of seawater along the swash zone strip of a sandy shore.
Background Art
It is known that draining tubes can be positioned buried, close to the strand of a coast line, in order to determine a reduction of the hydraulic pressure in the shore porous substrate and, as a consequence, to alter the normal reflux of the waves to favour the sedimentation of the solid particles suspended in the water. This enables to reset the coast line, where the currents otherwise tend to trigger the erosion of the beach.
Eu ropea n patent E P 0 1 08 269 il l ustrates a method for operating the sedimentation of a solid material in suspension in a natural water mass having a porous substrate. Such method provides for realizing an underground draining channel underneath the medium level of the water mass and for reducing the hydraulic pressure inside the porous substrate of the water mass along a zone adjacent to the draining channel, removing the water from the draining channel in a way as to take the sedimentation solid material to deposit in the aforesaid zone of the substrate. The draining channel is positioned in the substrate or in the land along a borderline between the water mass and the land, so as to lower the level of the ground water table in the zone adjacent to the land.
The described method reduces the reflux waves and favours the deposition of the suspended solid particles, with the effect of regenerating the coast tracts eroded and subjected to erosion.
Nevertheless the described method is not easy to actuate, because it requires the realization of a deep excavation close to the coast line, which can only be made with qu iet sea and during the summer, unless provid ing important protections from the waves.
Italian patent IT 1 354 750 discloses a process for the buried positioning of draining tubes which provides for stretching in the soil, at the determined depth, a disposable link tube carrying an internal traction cable. On the draining line there are made wells that are joined by the disposable tube and by the traction cable. The disposable tube is thus joined to an ogive device fixed to the traction cable and drawn from a starting well to an arrival well. During the advancement, the ogive device releases a sock of low friction material suitable to delimit a cavity within which the draining tube is made sliding, drawn by the traction cable, until anchoring its ends respectively to the starting well and to the arrival well. Also this solution has proved to be complex to actuate, even if it allows to perform works in any period of the year.
Disclosure of invention
The task of the present invention is that of solving the aforementioned problem, devising a method and an equipment that allow to operate in an optimal way the catchment of seawater along the swash zone strip of a sandy shore.
Within such a task, a further scope of the present invention is that of providing an equipment for the catchment of seawater that does not alter the naturalness level of the sea landscape and does not produce negative effects on the biological component of the littoral ecosystem.
Another object of the invention is that of provid ing an equipment for the catchment of seawater having a sim ple conception , a securely rel iable functioning and versatile use, as well as relatively economic cost.
The above mentioned scopes are attained, according to the present invention, by the method and by the equipment for the catchment of seawater according to claims 1 and 2.
The method for the catchment of seawater provides for realizing an excavation along the swash zone line of a sandy shore, at a definite depth under the sea level, and introducing at the bottom of the excavation a collection tank for the drained waters, having an opening in the upper part. The upper opening of the collection tank is closed through a filtering element consisting of a fabric tubular member suitable to be filled with an inert filtering material. The filtering element is fastened to the collection tank through support means. The collection tank is buried to drain inside it a flux of seawater conveyed on the shore by the sea, taking advantage of the gravity filtration motion through the sandy shore.
Accord ing to a preferred embod iment of the invention, the collection tan k consists of a series of reinforced concrete pools, arranged in line and modularly connected to one another.
Furthermore the filtering element is advantageously made of a biaxial fabric tubular element consisting of fibrillated filaments in black polypropylene fibre. Brief Description of the Drawings
Details of the invention shall be more apparent from the detailed description of a preferred embodiment of the equipment for the catchment of seawater according to the invention, illustrated for indicative purposes in the attached drawings, wherein:
figure 1 shows a scheme section view of a sandy shore tract wherein is arranged the equipment for the catchment of seawater;
figure 2 shows a perspective scheme view of the equipment for the catchment of seawater;
figure 3 shows a prospective view of a modular element of the equipment in hand.
Best Modes of Carrying Out the Invention
With particular reference to such figures, the equipment for the catchment of seawater is indicated in its entirety with 1 . The equipment 1 is designed to be arranged along the swash zone line of a sandy shore 2, at a defined depth under the sea level L.
The equipment 1 provides a collection tank 10 of the drained waters having an opening in the upper part. The tank 10 is preferably constituted by a series of reinforced concrete pools 1 1 , arranged in line and modularly connected to one another. The pools 1 1 have a substantially trapezoid profile transverse section, of suitable width with respect to the hydrostatic thrusts that may trigger structure floating, overturning or collapsing phenomena.
The pools 1 1 are suitable to be connected to one another through pipe elements 12 which cross the front walls 1 1 a of the pools 1 1 . Suitably, the pipe elements 12 are axially slidable with respect to the walls 1 1 a of the pools 1 1 , through suitable tight means, so as to facilitate the coupling in the seats prearranged on such walls 1 1 a. But obviously it is possible to provide for the junction to be made in a different manner, for example through flange members and the like.
The pools 1 1 constituting the draining tank 10 are designed to be introduced at the bottom of a trench 3 excavated in the sandy shore 2, preferably with terraces. In order to be able to perform the excavation and the installation of the draining tank 10, there is provided the installation, parallel to the swash zone line, of a system for pulling down the piezometric surface 20 of the type known as "well-point", consisting of a plurality of vertical tubes 21 stuck in the soil at regular distances and connected at the top by a collector tube 22.
At the top of the pools 1 1 there are fixed a series of transverse plates 13, preferably made of steel. The plates 13 are regularly spaced to one another, with suitable spacing to ensure the resistance against the external loads.
The plates 1 3 form a support plane for a draining cushion 14 so-called "geocomposite", arranged substantially horizontal in use. The draining cushion is made of a draining core consisting of a tridimensional woven roving with cusp- shaped structure consisting of monofilament yarns of polypropylene heat-welded in the contact points. The draining woven roving is thermally coupled in the upper part to a layer of textile material with a function of separation and filtration. The woven roving has the function of giving a major punch resistance to the textile layer.
The draining cushion 14 functions as a base for a tubular element 15 so-called "geotube", made of a biaxial fabric consisting of fibrillated filaments in black polypropylene fibre. The polypropylene tubular element 15 is suitable to be filled with an inert filtering material of alluvial origins. Such an inert material suitably consists of fine grovel with coarse sand , containing 98% of quartz, having substantially rounded grains so as not to damage the textile material with which it is in contact.
The draining cushion 14 and the tubular element 15 have lengths substantially equal to the length of the relative pool 1 1 .
For a major stability security, the polypropylene tubular element 15 is suitably anchored to the pool 1 1 of the draining tank 10, for example at end portions of the plates 13 protruding from the same pool 1 1 .
The method for the catchment of seawater turns out to be easy to understand from the preceding description.
In order to set up the equipment, one first provides to make an excavation along the swash zone line of the sandy shore 2, at a defined depth under the sea level L, and thus the pools 1 1 constituting the collection tank 10 of the drained waters are introduced at the bottom of such an excavation . The pools 1 1 are then modularly connected to one another through the pipe means 12.
The upper opening of the pools 1 1 is then closed through the draining cushion 14 and the fabric tubular element 15 filled with inert filtering material, suitably fastened to the same pools 1 1 .
Finally the collection tank 10 is buried so as not to result visible.
Such equipment thus enables to drain inside the collection tank 10 a flux of seawater conveyed on the shore by the sea, taking advantage of the gravity filtration motion through the sand of the sandy shore 2.
Furthermore, it is to note that the lowering of the ground water table produced by the catchment equipment allows the stabilization of the sand and a sensible reduction of the return flux, thus favouring the deposition of sediments on the swash zone. For the only catchment of seawater, the sedimentation processes induced by the draining are anyway considered secondary in the dimensioning of the equipment, privileging vice versa the capacity of absorbing suitable water volumes and ensuring the required ranges.
The water collected in the tank 10 is suitably evacuated, for example providing the same tank with a light slope, such as to convey the water to an evacuation area. In particular, it is possible to provide that the water collected by the pools 1 1 is conveyed, through suitable pipes, to an auxil iary tan k with a suitable capacity, provided with suitable pumping members. Upon reaching a prefixed filling level, the pumping members are actuated to perform the emptying of the auxiliary tank.
The described method and equipment attain the scope of optimally operating the catchment of seawater along the swash zone line of a sandy shore, taking advantage of the gravity filtration motion through the same sandy shore, intended as permeable porous means able to absorb the fluxes of water conveyed on shore by the sea state.
In facts the catchment method produces a lowering of the saturation line of the ground water table close to the shore line, amplifying the natural percolation of the seawater in the area interested by the sea state.
Therefore the catchment equipment can also be proposed as system for the stabilization and increasing of the sandy shore, as it favours the sedimentation processes of the suspended solid transported by the sea state and inhibits the transport of sediment towards the open sea in the step of ebb of the wave from the swash zone.
A feature of the method and of the equipment in hand consists of the fact that the naturalness level of the sea landscape is not troubled and no negative effect is produced on the biological component of the littoral ecosystem. Once installed, the equipment does not present any visible part.
The zone of sedimentologic modification or of coastal transport following the activation of the system is limited to a few meters distance from the swash zone line to the submerged beach, therefore there are not any influences with respect