LU101278B1 - Rainwater cistern - Google Patents

Abstract

The cistern has an inner wall of porous concrete (8) to define a storage space (3.30) and a buffer space (9.90.91). The inner wall is made of a draining concrete with a maximum permeability to water of 0.05 liter / m2 / s to 5 liters / m2 / s inclusive, preferably from 0.1 liter / m2 / s to 3 liters / m2 / s inclusive, the water permeability being measured in the case of a storage space practically filled with water (3).

Description

BL-5093 Rainwater Cistern The invention relates to a water buffer system, in particular a rainwater buffer tank. More and more houses and other buildings are equipped with water tanks to store rainwater. If the water consumption is insufficient, the water tanks remain practically full of water and, in the event of heavy precipitation, they offer no solution against the excessive discharge of water into the rivers.

A system which assembles plastic modules using a porous textile material is known to remedy the problems of storm rains. The construction of such a system requires underground work to achieve sufficient soil stability. A top coat is also required to allow passage over. Water tanks which can also be used as drainage systems are for example described in document WO95 / 16833. The drainage system according to this document uses perforated walls and a porous textile material to define a storage volume, the water flowing through the walls and the porous textile material to allow the infiltration of the water. water in the basement.

Such a system requires earthworks to be sure that the walls with the porous textile material are surrounded by a layer of porous soil. Moreover, in the case of wet soils, such systems are totally ineffective. This is because groundwater will flow through the porous side walls into the cistern, thus limiting the space for storing rainwater.

BL-5093 The use of porous concrete layers is known for driveways, roads and parking lots. Porous concrete, which has a very high permeability, is intended to convey water to a lower layer of the soil. As soon as this layer of soil is wet, the effectiveness of porous concrete is reduced.

DE9412053U1 describes a water cistern which is provided with a filter element and a flow opening located at a level above the filter element. The filter element therefore does not act as a means to control the drainage of rainwater.

Document US2012 / 0111428 describes a water tank made of HDPE for collecting rainwater, the water tank being provided with a filter structure with a filter sheet to retain solid particles from it. a diameter of 20 µm. Such a filter does not work as a means to control the drainage of rainwater.

Document DE10231241 describes a porous concrete filter element. The water flows from the bottom up through the porous concrete. Also, as soon as there is too much rainwater, the solid particles settle on the horizontal filter element so that the rainwater discharge cannot be controlled.

DE4338085 describes a filtering installation with horizontal filtering elements for filtering rainwater. Such an installation does not function as a means of controlling the drainage of rainwater from the cistern.

All of these known systems do not offer an effective solution for controlling the evacuation of rainwater to streams or rivers during a period of rain and afterwards, for example in the case where the soil is already too wet.

BL-5093 The invention relates to a water buffer system for storing rainwater / water.

With the buffer system according to the invention, the arrangement of a layer of porous earth all around the water tank is no longer necessary.

The drainage of rainwater does not depend on the layer of soil in which the water tank is placed.

By effectively regulating the drainage of rainwater by means of one or more buffer systems according to the invention, it is possible to regulate the flow of water flowing to rivers, ditches, streams, flood zones, etc.

The water buffer systems according to the invention can also be used as a means to regulate the water level in canals, ditches, rivers, etc.

For example, the water buffer systems according to the invention can be used along dikes, dams, towpaths or inspection routes of canals, ditches, streams, rivers, etc. (and / or part of them) to regulate the water level, at least partially.

If necessary, the vertical porous concrete inner wall can be easily cleaned.

The buffer system according to the invention includes at least one buffer tank (T) for the collection and storage (at least temporarily) of rainwater / water and for controlled drainage of the water.

The water tank of the buffer system according to the invention comprises at least: - one or more external walls (1) which are made from non-porous concrete and define an internal volume (2), part of which acts as rainwater / water storage space (3) with storage space for rainwater / water; - an inlet opening (4) through which rainwater / water can flow into the storage space (3):

BL-5093 - a drainage opening (5) for draining rainwater / water out of the water tank (T); - a cover (6) with an inspection window (7); and - a control system (5,8) to control the discharge rate of rainwater / water out of the water tank (T).

According to the invention, the control system (5,8) consists of at least one or more vertical interior walls of porous concrete (8) which extend into the interior volume (2) of the water tank ( T) and which divides (s) this interior volume at least into a storage space (3) for rainwater / water and a buffer space (9) with a buffer volume to collect the water that s' flows through the interior wall or walls of porous concrete (8).

The buffer space (9) has the drainage opening (5) for draining rainwater / water, while the vertical interior wall (s) of porous concrete (8) are made of a hardened drainage concrete made by hardening a mixture comprising at least cement, aggregates with a particle size of 6 mm to 14 mm inclusive and water to obtain an open pore volume of 8 to 12% inclusive in the hardened porous drainage concrete, the hardened porous drainage concrete having a water permeability of 0.05 liter / m? / s to 5 liters / m? / s, preferably from 0.1 liter / m? / s to 3 liters / m? / S included and, more particularly, between 0.1 liter / m? / S and | liter / m? / s (as 0.1; 0.2; 0.4; 0.5; 0.7; 0.8 and 1 liter / m? / s), this water permeability being measured for a storage space almost completely filled with water (3) and a substantially empty buffer space (9).

The specifics and characteristics of advantageous variants of the buffer system according to the invention or of the water tank of the buffer system according to the invention are one or more of the following:

BL-5093 - the water tank (T) has a height of less than 3 m, preferably between 1 and 2.5 m;

5 - in its first variant execution (fig. 1), the total water evacuation capacity varies linearly with the depth of water present between 0% and 100%;

- in a second variant embodiment, the total water evacuation capacity measured for a water height equal to half of the storage space and, preferably, at a water height of 0.3 m is equal to 80% to 100% inclusive, preferably 90% to 100% inclusive of that measured in the case of a storage space almost completely filled with water (3) and a substantially empty buffer space (9); - the hardened porous drainage concrete has one or more zones having a higher permeability to water compared to the average permeability to water of the hardened porous drainage concrete, this or these zones (10) being situated at a height (h) from the bottom (3B) of the storage space (3) which is less than 50 cm, and preferably less than 30 cm.

In this way, it is easier to regulate the drainage of rainwater.

Under normal rainfall, the water flowing into the water tank is discharged with minimal delay to the stream.

In this case, the storage space is only partially used.

In the event of heavy rain showers, the storage space and buffer space are almost full.

The flow of water that is discharged to the stream is practically limited by the passage of the flow opening (5). The storage space acts as the primary means to regulate / regulate the flow of rainwater to the stream, ditch, canal, river, etc.

As soon as this storage space is full, the buffer space then acts as additional storage space and as a buffer for rainwater;

- the ratio of storage space (3) / buffer space (9) of

BL-5093 the water tank (T) is greater than or equal to 2, preferably greater than 5 and, in particular, is located between 5 and 20; - the vertical interior wall (s) made of porous concrete (8) of the water tank (T) define a porous surface which faces the storage space (3), the ratio between the storage volume (3) in m ? and the porous surface in m? being between 0.5 and 1.5; - the flow opening (5) for the evacuation of rainwater has a passage which makes it possible to limit the flow of water evacuation through this flow opening (5) between 1 and 20 liters / second , preferably at 5 liters / second maximum (this flow opening can optionally be provided with a valve or a valve mechanism to limit the water discharge rate, for example to |; 2; 3

; 4; 5; 10 liters / s); - The buffer system has a flow opening (5) for the evacuation of rainwater, the flow opening (5) having a passage system which makes it possible to limit the evacuation flow rate. water through this flow opening (5) between 1 and 20 liters / second, preferably at 5 liters / second maximum as long as the water level in the storage space (3) is below a level of maximum water.

The passage system has a porous concrete element with an interior compartment which is connected to the flow opening (5) via a pipe system.

The porous concrete element is composed, at least in part, of a cured porous drainage concrete made by curing a mixture comprising at least cement, aggregates with a particle size of 6 mm to 14 mm inclusive and water to obtain an open pore volume of 8 to 12% included in the cured porous drainage concrete. - The water tank has an interior wall in porous concrete that is almost vertical which divides the internal volume of the water tank into a storage space (3) and a buffer space (9), the buffer space ( 9)

of the water tank (T) being connected by a connection pipe to a buffer tank (BT), this connection pipe being maintained at a

BL-5093 upper level at the bottom of the buffer space (9) and at the bottom of the buffer tank (BT). The buffer tank has a flow opening (50) which is located above the bottom of the buffer tank (BT), the flow opening (50) having a flow system suitable for limit the water discharge rate through this flow opening (50) between 1 and 20 liters / second, preferably to 5 liters / second maximum or is connected to such a passage system, the passage system comprising a porous concrete element with an interior chamber which is connected via a pipe system with the flow opening (50), the porous concrete element being made, at least in part, from a cured porous drainage concrete which is made by curing a mixture comprising at least cement, aggregates with a particle size of 6 mm to 14 mm inclusive and water to obtain an open pore volume of 8 to 12% inclusive in the hardened porous drainage concrete.

The passage system is preferably located in the buffer tank (BT). - The porous concrete element is supported on the bottom of the buffer space (9) or of the buffer tank (BT), the porous concrete element containing one or more porous walls as well as a porous upper face, the system of pipes preferably being provided with an overflow system to evacuate water as soon as the water level in the buffer space or in the buffer tank exceeds a higher level. -The water tank or the water tank of the buffer system has at least two separate overflows (3A, 9A) namely a first overflow (3A) for the storage space (3) for the evacuation of rainwater as soon as the water level in the storage space (3) exceeds the level (H3A) of this first overflow (3A) and a second overflow (9A) for the buffer space (9) for evacuating rainwater as soon as the water level in the buffer space (9) exceeds the level (H9A) of this second overflow (9A);

- The first overflow (3A) is located, at least in part, at a level

BL-5093 (H3A) which is located below the lowest level (H9A) of the second overflow (9A). These two overflows can drain water through the same drainage pipe to a stream or river;

- The first overflow (3A) has a passage surface which is greater than the passage surface of the second overflow (9A); - The porous concrete vertical interior wall (s) (8) have an upper face (8B) which is located at a level (H8B) higher than the lower edge of the first overflow (3A) and at the lower edge of the second overflow ( 9A). This is to prevent water from flowing over the upper edge of the inner wall (8);

- At least one vertical interior wall of porous concrete (8) is mounted in a movable and / or removable manner relative to the water tank, a lower edge (8X) of the interior wall being able to rest on the bottom of the tank d 'water (T). This is advantageous for assembly and / or maintenance work;

- The water tank has a removable cover with inspection window;

- The water tank has at least two separate buffer spaces,

namely at least a first buffer space (90) which is located along the bottom of a storage space (3), this first buffer space (90) collecting water from the storage space (3) by by means of a porous concrete wall at least partly horizontal (80) and at least one second buffer space (9) which cooperates with an almost vertical porous concrete wall (8) to collect water from the space storage (3), and characterized in that the first buffer space (90) and the second buffer space (9) are connected by a pipe or channel (100) which is preferably located along the bottom of the the water tank;

- The first buffer space (90) and the second buffer space (9)

BL-5093 are connected by a pipe or channel (100) with an upper edge (100A) which has a slope with respect to a horizontal plane, so that this upper edge (100A) is raised in the direction of the second buffer space (9); - The water tank (T) has at least two separate storage spaces (3.30), these two separate storage spaces (3.30) being connected by means of an overflow pipe (31 ) which is intended to transfer water from a first storage space (3) to a second storage space (30) as soon as the first storage space (3) is practically full of water, the second storage space (30) being provided with an overflow (3A) which is located at a lower level than the overflow pipe (31); - The inlet opening (4) is fitted with a system by which, if the flow of rainwater flowing into the cistern through the inlet opening (4) is less than a determined flow , the system is suitable for evacuating directly at least part of the rainwater flow towards the buffer space of the water tank; - Combinations of two or more of these specificities and / or characteristics.

The invention also relates to the use of one or more buffer systems according to the invention for regulating the flow rates and / or water levels in streams and / or rivers and / or ditches and / or areas liable to flooding by the regulation. / the adjustment of the discharge rates for rainwater from roofs, walkways, roads and / or water from a canal, stream, ditch or river , rainwater and / or water flowing towards one or more storage spaces of one or more buffer systems according to the invention and this rainwater and / or water being caused to flow through the / the vertical porous concrete walls of the water tanks towards their buffer spaces before being evacuated to streams and / or rivers and / or ditches and / or flood zones.

BL-5093 Specific embodiments according to the invention will now be described as advantageous examples according to the invention.

This description refers to the accompanying drawings.

These drawings illustrate:

- Fig. 1, a top view of a first variant embodiment of a buffer system (water tank T) according to the invention, - Fig. 2, a view of the water tank of Figure 1 in cross section along the line II-IT,

- Fig. 3, a view from above of a second variant embodiment of a water tank according to the invention, - Fig. 4 to 6 inclusive, respective cross-sectional views of the water tank of Figure 3 along lines IV-IV, V-V and VI-VI, - Fig. 7, a view of a detail of the water tank in figure 3,

- Fig. 8A and Fig. 8B, views of a detail of an inlet opening for a water tank according to the invention, - Fig. 9, a view of two water tanks which are connected by means of pipes, - Fig. 10, a vertical sectional view of a third variant embodiment according to the invention, - Fig. 11, a cross-sectional view along the line XI-XI in figure 10, - Fig. 12, a top view of a fourth variant embodiment which is identical to the variant embodiment of Figure 3,

- Fig. 13, a cross-sectional view along the line XIII-XIII in figure 12, - Fig. 14, a view of part of an inspection track along a canal or ditch, with a series of water tanks according to the invention, - Fig. 15, a top view of a fourth variant embodiment,

- Fig. 16, a cross-sectional view along the line XVI-XVI in figure 15, - Fig. 17, a top view of a fifth embodiment of a buffer system according to the invention, - Fig. 18, a cross-sectional view along line XVIII-

XVIII in figure 17, - Fig. 19, a view from above of a sixth variant execution of a

BL-5093 buffer system according to the invention, - Fig. 20, a cross-sectional view along line XX-XX in Figure 19, and - Fig. 21, a cross-sectional view of a seventh variant embodiment. Figure 1 shows a water tank (T) for collecting and storing rainwater. This water tank comprises: - one or more exterior walls (1) which are made from non-porous concrete and define an interior volume (2), part of which acts as a storage space (3) of the rainwater / water with storage volume for rainwater / water; - an inlet opening (4) through which rainwater / water can flow into the storage space (3); - a drainage opening (5) for draining rainwater / water out of the water tank (T); - a cover (6) with an inspection window (7); and - a control system (5,8) to control the discharge rate of rainwater / water out of the water tank (T).

The control system (5,8) consists of at least one or more vertical interior walls of porous concrete (8) which. extend into the interior volume (2) of the water tank (T) and which divides (s) this interior volume at least into a storage space (3) for rainwater / water and a buffer space (9) with a buffer volume to collect the water which flows through the interior wall or walls of porous concrete (8).

The buffer space (9) is provided with the drainage opening (5) for the drainage of rainwater. This flow opening is located along the bottom of the tank (T).

BL-5093 The porous concrete inner wall (8) is made of special draining concrete to obtain suitable permeability to water. Drainage concrete has a minimum water permeability of 0.05 liter / m? / S and a maximum water permeability of 0.1 liter / m? / S to 5 liters / m? / S, preferably from 0.1 liter / m? / s to 1 liter / m? / s, for example 0.2 to 0.75 liter / m? / s inclusive. The minimum permeability to water is preferably 0.2 to 0.5 liter / m 2 / s.

This water permeability of this vertical porous interior wall is measured for a storage space (3) which is practically full of water, while the buffer space (9) is practically empty. For this measurement, for example, a pump is used to keep the buffer space practically empty.

The maximum permeability to water of the draining concrete can also be determined by making a porous concrete plate which serves as the bottom of a test tank. The test vessel (of a height equal to the height of the vessel) will then be filled with water and the water flow will be measured for the water flowing through the porous bottom.

Drainage concrete is preferably made by curing a mixture of cement, aggregate and water to preferably achieve a total open pore volume of 8-12% included in the cured concrete. For concrete, aggregates with a particle size of 6 mm to 14 mm inclusive are preferably used. Preferably, the aggregates of the drainage concrete contain 15% by weight of aggregates with a particle size greater than 8 mm, while the proportion by weight of water / cement is less than 0.5 and ideally situated between 0.35 and 0 , 42.

The uncured concrete mix (without water) contains less than 30% by weight of aggregate, better still between 25 and 27% by weight with a grain size of less than 4 mm. The concrete mix can also contain one or more additives.

BL-5093 The uncured concrete mix (without water) may contain up to 15% by weight of sand, with a particle size of less than 4 mm, for example 2 to 4 mm. The sand is preferably formed of round grains and comes for example from a river. Examples of sand contents are 2; 5; 8; 10; 12% by weight.

In order to even better control the water permeability of the concrete, one or more additives may be added to the hardened concrete mixture, such as an aqueous dispersion of polymer, in particular an aqueous dispersion of polymer / acrylate / methacrylate copolymer, for example a copolymer of an aqueous dispersion of acrylic acid ester / vinyl ester. For example, 10 to 30% by weight of a polymer dispersion can be added in concrete, this percentage by weight being measured relative to the weight of cement.

The water tank has a height (H) of less than 3 m, for example 2 to 2.5 m.

The height of the tank is preferably greater than 1 m.

In its first variant execution (Figure 1), the total water evacuation capacity varies linearly with the depth of water present between 0% and 100%.

In a second variant embodiment, the total water evacuation capacity measured for a water height corresponding to half of the storage space and, preferably, to a water height of 0.3 m , is equal to 80% to 100%, preferably 90% to 100% inclusive of that measured in the case of storage space almost completely filled with water (3).

This property provides better control of the water flowing through the porous wall.

BL-5093 In the variant execution of figure 3, the porous concrete contains several zones (10) with a higher permeability to water compared to the average permeability to water of the porous concrete. These zones (10) are located in the vicinity of the bottom, for example at a height (h) from the bottom (3B) of the storage space (3) which is less than 50 cm and, preferably, less than 30 cm .

These zones (10) can be manufactured using aggregates with a larger particle size. These zones can also form an intermediate layer in the porous wall, this intermediate layer being situated at a height between 20 and 50 centimeters relative to the bottom (3B).

The storage space (3) / buffer space (9) volume ratio is greater than or equal to 2, preferably greater than 5 and, in particular, between 5 and 20.

The porous concrete inner wall (8) defines a porous surface which faces the storage space (3), the storage volume (3) ratio in m * / porous surface in m? being between 0.5 and 1.5 (for example, between 0.7 and 1.25, preferably 0.8; 0.9; 1; 1.1 and 1.2). This ratio provides good control of the maximum flow rate of the water flowing through the porous wall and sufficient storage volume for rainwater.

The drain opening (5) for the evacuation of rainwater has a passage suitable for limiting the flow of water evacuation through this drain opening (5) between 1 and 20 liters / second , preferably at 5 liters / s maximum.

The water tank is fitted with at least two separate overflows (3A, 9A), namely a first overflow (3A) for the storage space (3) for the drainage of rainwater storage space as soon as the water level in the storage space (3) exceeds the level (H3A) of this first overflow (3A) and a second overflow (9A) for the space buffer (9) for draining water from

BL-5093 rain as soon as the water level in the buffer space (9) exceeds the level (H9A) of this second overflow (9A).

Through these overflows 3A, 9A, two water tanks T, T1 according to the invention can be connected by pipes 20,21. The tank T1 is for example located at a lower level compared to the tank T so that the water can flow freely from the tank T to the tank T1. The overflow opening 3A of tank T is connected to the inlet opening 4 of tank T1 via pipe 20. As soon as the storage space 3 of tank T is full, the water flows from this storage space 3 to the storage space 3a of the tank T1. (see figure 9) The overflow 9A of the buffer space 9 of the tank T is provided with an inlet 40 via the pipe 21. In the case where the buffer space 9 of the tank T is practically full, the water then flows from the buffer space of the tank T to the buffer space 9 of the tank T1. Through the pipes 22, the water is discharged from the buffer spaces 9 of the tanks T and T1 to the stream S.

The first overflow (3A) is located, at least in part, at a level (H3A) which is located above the lowest level (H9A) of the second overflow (9A).

The first overflow (3A) has a passage area which is greater than the passage area of the second overflow (9A).

With these overflows 3A, 9A, the water level in buffer space 9 is always lower than the water level in storage space 3, even in a stormy rain.

The porous concrete inner wall (8) has an upper face (8B) which is at a level (H8B) higher than the edge

BL-5093 lower of the first overflow (3A) and at the lower edge of the second overflow (9A). This is advantageous to prevent water from flowing over the inner wall of the storage space to the buffer space 9.

In the variant embodiment shown in Figure 1, the cover 6 is removably mounted on the tank 1. In this case, it is also advantageous to mount the porous concrete inner wall 8 removably in the tank. The lower edge 8X of the wall (8) rests on the bottom of the tank, possibly with a rubber spacer. The inspection window 7 provides a view of the water level in the two spaces (3, 9). Maintenance work can also be carried out through this manhole in the tank. In the variant embodiment of Figure 3, the water tank comprises three or more than three separate buffer spaces (9, 90, 91), namely (a) at least first and second buffer spaces (90, 91 ) which are located along the bottom of a storage space (3), the first and second buffer spaces (90) collecting water from the storage spaces (3, 30) via a concrete wall porous at least partly horizontal (80, 81) and (b) at least a third central buffer space (9) which works together with two almost vertical porous concrete walls (8,8 bis) to collect water from the storage spaces (3, 30). The position of the porous walls 80, 81 along the bottom of the tank can be maintained by fixing means (rods 111). The first and second buffer spaces are connected with the third buffer space (9) by pipes (100) which are located along the bottom of the water tank. The pipes 100 show a slope with respect to the horizontal plane so that the upper edge (100A) of these pipes rises in the direction

BL-5093 of the third buffer space (9). In this way, it is possible to prevent air or gas from remaining in the buffer spaces 90, 91, which can be detrimental to the passage of water.

The two separate storage spaces (3.30) are connected via an overflow pipe (31). This pipe 31 is intended to evacuate water from the first storage space (3) to the second storage space (30) as soon as the first storage space (3) is practically full of water, the second storage space (30) being provided with an overflow (3A) which is located under the overflow pipe (31). In a possible variant embodiment, the inlet opening (4) can be provided with a control system 400, so that the rainwater flow rate which flows into the tank T is less than a given flow, the control system 400 is adapted to directly evacuate at least part of the rainwater flow towards the buffer space 9. With such a control system 400, the rainwater can be partially evacuated. towards storage space 3, as well as partly towards the buffer space, for short-term precipitation without stormy character. Such a system is illustrated in Figures 8A and 8B. The rainwater W flows into a chamber 401 which is provided with an open inner vessel 402 in order to collect at least part of the rainwater. The bottom of this 402 vase has a 402A hole. In this vessel, a float 403 moves with a surface 403A which acts as a valve system. The inner vessel 402 is connected with an inlet opening 40 of the buffer space 9 via a pipe 41. For small water flows W, the water flows into the inner vessel 402. Since the flow is not sufficient, the float 403 remains in a lower position so that part of the rain flows directly to the buffer space 9, while another part.

BL-5093 part flows to storage space 3 through opening 402A (see Figure 8A).

In the event of a thunderstorm rain, the water level in the inner vessel rises so that the float 403 is in the closed position to (possibly partially) block the inlet of the pipe 41. In such a closed position, almost all the rain flows into the storage space of the T tank.

A third variant embodiment of a water tank according to the invention is illustrated in Figure 10.

Tank T contains a concrete tank (watertight) with a flow 5 along the bottom 1B. Along the bottom 1B, the tank is equipped with one or more support elements 1C for a plate 80 of porous concrete. The round plate 80 rests on the supporting elements 1C. Above the plate 80 is a cylindrical pipe 82 of porous concrete.

The plate 80 may optionally be provided with a hole 80G to connect the buffer zones 9, 90 to one another. If this plate 80 is not provided with the hole 80G, the buffer spaces are connected via the open pores of plate 80.

The cylindrical pipe 82 can preferably be placed in the tank via the inspection manhole 7. The correct placement of the pipe can be obtained by intermediate elements 110 which are located between the upper edge of the pipe 82 and the surface. lower cover.

Figs. 12 and 13 are views of an alternative embodiment equivalent to the alternative embodiment of Figures 3 to 6 inclusive, with some modifications.

The tank and / or the vertical porous walls 8, 8a are provided with support elements 1C for the porous plates 80, 81. The

BL-5093 position of the plates on the support elements 1C is maintained by the use of fixing means 111 which are housed for example in part in a wall of the tank.

FIG. 14 is a view of a ditch or channel 200 with a dam 201 and two inspection lanes 202, 203. Along the inspection lane 203 are arranged several water tanks according to the invention. The water tank 1 is connected with the channel 200 via the pipe 204. The storage spaces for the water tanks 1,1 bis, lter, etc. are connected so that the water in the storage space of the tank 1 can be evacuated to the storage space of the tank 1bis as soon as the water level in the storage space 3 of the tank 1 exceeds a specified level.

The outlets 5 of all tanks 1,1 bis, etc. are connected to a flow pipe 205 to drain water into the channel 200, after the dam 201.

The water tanks according to the invention can therefore be used to regulate the water level in the canal. As soon as the water level exceeds a maximum level, water tanks 1.1 bis, etc. can collect water from the canal before it is delayed into the canal, which offers a solution against storm rains (with heavy rainfall in a short period of time).

Since water tanks can be arranged under inspection lanes, the fitting out of these cisterns can be done at the same time as fitting out those inspection lanes.

Figures 15 to 21 inclusive are views of alternative embodiments of buffer systems according to the invention.

In the variant embodiment of figures 15 and 16, the buffer system contains a rectangular T tank with a vertical porous concrete inner wall (8) which distributes the internal volume of the tank into a storage space (3) and a space buffer (9).

BL-5093 The tank T also has an inlet opening (4) which is located at a level higher than the upper level of the interior wall (8), the water being able to flow directly into the buffer space (9 ) in the event of a thunderstorm. Storm rains can then be discharged through an overflow pipe (51) which is connected to the outlet (5).

The discharge opening (5) is connected with a porous concrete element (85) via a horizontal pipe (86) (which is at a distance from the bottom of the buffer space). The porous concrete element (85) defines an interior chamber (87) (for collecting water flowing through the porous walls of the element (85)) connected through a pipe system ( 86) with the discharge opening (5). The porous concrete element is made, at least in part, from a cured porous drainage concrete which is made by curing a mixture of cement, aggregates with a grain size of 6mm to 14mm inclusive and water for an open pore volume of 8 to 12% included in the cured porous drainage concrete.

The open interior chamber 87 is connected to the overflow pipe.

The variant embodiment of Figures 17 and 18 is similar to the variant embodiment of Figures 15 and 16. The buffer system of Figures 17 and 18 contains a water tank (T) whose buffer space is connected to a buffer tank (BT) via a connection pipe 55. The connection pipe 55 is located at a level above the bottom of the buffer space (9) of the T tank and the bottom of the buffer tank (BT).

The buffer tank has a flow opening (50) which is located above the bottom of the buffer tank, the flow opening (50) being connected with a passage system suitable to limit the flow. water discharge through this opening

BL-5093 flow rate (50) between 1 and 20 liters / second and preferably at 5 liters / second maximum. The passage system contains a porous concrete element (85) with an interior chamber (87) which is connected to the flow opening (50) via a pipe system (86). The porous concrete element is made, at least in part, of a cured porous draining concrete which is made by curing a mixture comprising at least cement, aggregates with a particle size of 6 mm to 14 mm inclusive and l water to obtain an open pore volume of 8 to 12% included in the cured porous drainage concrete.

The porous concrete element rests on the bottom of the buffer space (9bis) or of the buffer tank (BT), the porous concrete element (85) comprising one or more porous walls as well as a porous upper face and , preferably, the pipe system 86 being provided with an overflow system (pipe 51) for discharging water as soon as the water level in the buffer space (9) or in the buffer tank ( BT) exceeds a higher level (for example, a level near the upper edge of the inner wall (8)).

The buffer system of Figures 19 and 20 is equivalent to the buffer system of Figures 17 and 18 except that the line 51 is connected to the interior chamber (87) of the porous element (85).

Figure 21 shows a buffer system with several tanks T1, T2, etc. to collect rainwater that are connected to each other. The tanks are therefore connected to a buffer system according to the invention to control the water discharge (water tank (T) with porous vertical interior wall (8) and buffer tank (BT) with element (85)).

Claims (13)

BL-5093 CLAIMS 1. Buffer system for rainwater / water which includes at least one water cistern (T) for the collection and at least temporary storage of rainwater / water, and for controlled drainage of water. , the water tank (T) comprising at least: - one or more external walls (1) which are made from non-porous concrete and define an internal volume (2), part of which acts as a storage space (3) rainwater / water with storage volume for rainwater / water; - an inlet opening (4) through which rainwater / water can flow into the storage space (3); - a drainage opening (5) for draining rainwater / water out of the water tank (T); - a cover (6) with an inspection window (7); and - a control system (5, 8) for controlling the discharge rate of rainwater / water out of the water tank (T), characterized in that the control system (5 , 8) consists of at least one or more vertical interior walls of porous concrete (8) which extend into the interior volume (2) of the water tank (T) and which divide (s) this interior volume at least a storage space (3) for rainwater / water and a buffer space (9) with a buffer volume to collect the water flowing through where the porous concrete inner walls ( 8), characterized in that the buffer space (9) is provided with the outlet opening (5) for the drainage of rainwater / water, and characterized in that the one or more vertical porous concrete interior walls (8) are made of hardened drainage concrete made of BL-5093 hardening a mixture comprising at least cement, aggregates with a particle size of 6 mm to 14 mm inclusive and water to obtain an open pore volume of 8 to 12% included in the hardened porous drainage concrete , the cured porous drainage concrete exhibiting a water permeability of 0.05 liter / m? / s to 5 liters / m? / s, preferably 0.1 liter / m? / s to 3 liters / m? / s included and, more particularly, between 0.1 liter / m? / s and 1 liter / m? / s, this water permeability being measured for a storage space almost completely filled with water (3) and a substantially empty buffer space (9). 2. Buffer system according to claim 1, wherein the water tank (T) has a height (H) of less than 3 meters, characterized in that the total water discharge capacity measured for a height of water in half of the storage space (3) and, preferably, at a water height of 0.3 m in the storage space (3), is 80% to 100%, preferably 90% to 100% inclusive of that measured in the case of storage space (3) almost completely filled with water and a buffer space (9) substantially empty. 3. Buffer system according to one of claims 1 or 2, characterized in that the cured porous draining concrete has one or more zones having a higher permeability to water compared to the average water permeability of the draining concrete. porous hardened, this or these zones (10) located at a height (h) from the bottom (3B) of the storage space (3) which is less than 50 cm, and preferably less than 30 cm. 4. Buffer system according to one of the preceding claims, characterized in that the volume ratio of storage space (3) / buffer space (9) for the water tank (T) is greater than or equal to 2, preferably greater than 5 and, in particular, between 5 and 20. 5. Buffer system according to one of the preceding claims, characterized in that the inner wall or walls of porous concrete (8) of the water tank (T) define a porous surface which BL-5093 is oriented towards the storage space (3), the ratio of storage volume (3) in m ° / porous surface in m? being between 0.5 and 1.5. 6. Buffer system according to one of the preceding claims, characterized in that the buffer system has a flow opening (5) for draining rainwater, the flow opening (5) being provided. a passage system which makes it possible to limit the flow of water evacuation through this flow opening (5) between 1 and 20 liters / second, preferably to 5 liters / second maximum as long as the water level in the storage space (3) is below a maximum water level, in which the passage system has a porous concrete element with an interior compartment which is connected to the discharge opening (5) by the 'intermediary of a pipe system, and in which the porous concrete element is composed, at least in part, of a cured porous draining concrete made by curing a mixture comprising, in addition to cement, aggregates of a particle size of 6 mm to 14 mm inclusive and water to obtain an open pore volume of 8 to 12% inclusive in s cured porous drainage concrete. 7. Buffer system according to one of the preceding claims, characterized in that the water tank is provided with an interior wall of porous concrete almost vertical (8) which divides the interior volume of the water tank into a storage space (3) and a buffer space (9), in which the buffer space (9) of the water tank (T) is connected by a connecting pipe to a buffer tank (BT), this connection being maintained at a higher level than the bottom of the buffer space (9) and the bottom of the buffer tank (BT), and in which the buffer tank is provided with a flow opening (50) which is located at the above the bottom of the buffer tank (BT), the flow opening (50) being provided with a passage system which is suitable to limit the flow of water evacuation through this flow opening (50) between 1 and 20 liters / second, preferably at 5 liters / second maximum or is connected to such a passage system, the passage system comprising a porous concrete element with an interior chamber which is connected via BL-5093 of a pipe system with the drain opening (50), the porous concrete element being made, at least in part, from a cured porous drainage concrete which is made by curing a mixture comprising at least cement, aggregates with a particle size of 6 mm to 14 mm inclusive and water to obtain an open pore volume of 8 to 12% included in the hardened porous drainage concrete. 8. Buffer system according to one of claims 6 or 7 characterized in that the porous concrete element bears on the bottom of the buffer space (9) or of the buffer tank (BT), the concrete element porous containing one or more porous walls as well as a porous upper face, the piping system preferably being provided with an overflow system to evacuate the water as soon as the water level in the buffer space or in the the buffer tank exceeds a higher level. 9. Buffer system according to one of the preceding claims, characterized in that the water tank is provided with at least two separate overflows (3A, 9A) namely a first overflow (3A) for the storage space (3) for draining rainwater as soon as the water level in the storage space (3) exceeds the level (H3A) of this first overflow (3A) and a second overflow (9A) for the buffer space (9) for draining rainwater as soon as the water level in the buffer space (9) exceeds the level (H9A) of this second overflow full (9A). 10. Buffer system according to one of the preceding claims, characterized in that the water tank is provided with at least two separate buffer spaces, namely at least a first buffer space (90) which is located along the bottom. a storage space (3), this first buffer space (90) collecting water from the storage space (3) via a porous concrete wall at least partly horizontal (80) and at least one second buffer space (9) which cooperates with an almost vertical porous concrete wall (8) to collect water from the storage space (3), BL-5093 characterized in that the first buffer space (90) and the second buffer space (9) are connected by a pipe or channel (100) which is preferably located along the bottom of the tank of water. 11. Buffer system according to claim 10, characterized in that the water tank (T) has at least two separate storage spaces (3.30), these two separate storage spaces (3.30) being connected by the 'intermediate an overflow pipe (31) which is intended to transfer water from a first storage space (3) to a second storage space (30) as soon as the first storage space (3) is almost full of water, the second storage space (30) being provided with an overflow (3A) which is located at a lower level than the overflow pipe (31). 12. Buffer system according to one of the preceding claims, characterized in that the inlet opening (4) is provided with a system by which, if the flow of rainwater flowing into the tank through the inlet opening (4) is less than a determined flow rate, the system being adapted to directly evacuate at least part of the rainwater flow towards the buffer space (9) of the water tank. 13. Use of one or more buffer systems according to the invention for the regulation of the flow rates and / or water levels in streams and / or rivers and / or ditches and / or flood zones by the regulation / adjustment of the flow rates. drainage of rainwater from roofs, walkways, roads and / or water from a canal, stream, ditch or river, rainwater and / or the water flowing towards one or more storage spaces of one or more buffer systems according to the invention and this rainwater and / or water being caused to flow through the vertical porous concrete wall (s) from water tanks to their buffer spaces before being evacuated to streams and / or rivers and / or ditches and / or flood zones.