BE1026383B1 - Rainwater tank - Google Patents

Abstract

The tank is provided with a porous concrete inner wall (8) to define a storage space (3.30) and a buffer space (9.90.91). The inner wall is made of a water-draining concrete with a maximum water permeability of 0.05 liter / m² / s to 5 liter / m² / s, preferably from 0.1 liter / m² / s to 3 liter / m² / s, where the water permeability has been measured at an almost water-filled storage space (3).

Description

Rainwater tank

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. In case of insufficient water use, the water tanks remain almost full of water, and in case of heavy rain, they do not offer a solution against excessive water discharge to watercourses.

To solve problems with storm water, there is a system that combines plastic modules using a porous textile material. Building such a system requires underground works to obtain sufficient ground stability. A top layer would also be useful to be able to ride it.

Water tanks that can also be used as draining systems are described, for example, in WO95 / 16833. In the drainage system according to this document, perforated walls and porous textile material are used to define a storage volume, whereby water flows through the walls and the porous textile material to allow water to infiltrate the substrate.

Such a system requires earthworks to ensure that there is a porous primer around the walls with the porous textile material. In addition, in case of wet soils

BE2019 / 0054 such systems are totally inefficient. Indeed, groundwater will flow through the porous sidewalls in the tank, limiting space for rainwater collection.

The use of porous concrete layers is known for driveways, roads and parking. The porous concrete has a very high permeability and is intended to carry water to an underlying soil layer. Once that primer is wet, the efficiency of the porous concrete will decrease.

DE9412053U1 describes a water tank that is equipped with a filter element and with a discharge opening that is at a level above the filter element. The filter element therefore does not function as a means to control the drainage of rainwater.

US2012 / 0111428 describes a HDPE-manufactured water tank for collecting rainwater, in which the water tank is provided with a filter structure with a filter foil, to collect solid particles with a size from 20 µm. Such a filter does not work as a means to control the drainage of rainwater.

DEI0231241 describes a filter element made of porous concrete. The water flows from bottom to top through the porous concrete. In addition, as soon as there is too much rainwater, solid particles deposit on the horizontal filter element, so rainwater drainage cannot be controlled.

DE4338085 describes a filter installation with horizontal filter elements to filter the rainwater. Such an installation also does not work as a means to control the drainage of rainwater from the tank.

All these known systems do not offer efficient solutions for draining rainwater to streams or rivers

BE2019 / 0054 during a rainy period and after a rainy period, for example if the soil is already too wet.

The invention relates to a water buffer system for storing rainwater / water. With the buffer system according to the invention, the application of a porous primer around the water tank is no longer necessary. The drainage of rainwater does not depend on the base layer in which the water tank is placed. By effectively controlling the rainwater discharge by means of one or more buffer systems according to the invention, it is possible to control the water flow that flows to the rivers, canals, streams, flood areas, etc. Water buffer systems according to the invention can also be used as a means to control the water level in canals, canals, rivers, etc.

For example, water buffer systems according to the invention can be used along (and / or as part of) groynes, dams, towpaths and inspection paths of canals, canals, streams, rivers, etc. to at least partially control water levels.

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

The buffer system according to the invention contains at least one water tank (T) for collecting and (at least temporarily) storing rainwater / water, and for controlled water drainage. The water tank of the buffer system according to the invention comprises at least:

- one or more outer walls (1) which is / are made of non-porous concrete and which defines an inner volume (2), part of which serves as a rainwater / water storage space (3) with a rainwater / water storage volume;

- an inlet opening (4) along which rainwater / water can flow into the storage space (3);

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- an outlet opening (5) for draining rainwater / water from the water tank (T);

- a lid (6) with a manhole (7); and

- a control system (5.8) to check the rainwater / water discharge flow rate from the water tank (T).

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

The buffer space (9) is provided with the outlet opening (5) for draining rainwater / water, while the porous concrete vertical inner wall (s) (8) is / are made of a hardened water-draining concrete which is manufactured by hardening a mixture of at least cement, aggregates with particle size from 6mm to 14mm and water to obtain an open pore volume of 8 to 12% in the hardened porous water-draining concrete, whereby the hardened porous water-draining concrete has a water permeability of 0.05 liters / m ² / s to 5 liters / m ² / s, preferably from 0.1 liters / m ² / s to 3 liters / m ² / s, and most preferably between 0.1 liters / m ² / s s to 1 liter / m ² / s (such as 0.1; 0.2; 0.4; 0.5; 0.7; 0.8 and 1 liter / m ² / s), where that water permeability is measured with an almost water-filled storage space (3) and an empty buffer space (9).

Details and features of advantageous embodiments 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:

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

- in its first embodiment (fig 1), the total water discharge capacity varies linearly with the available water height between 0% and 100%,

- in a second embodiment, the total water discharge capacity is measured at a water height of half of the storage space, and preferably at a water height of 0.3 m, equal to 80% to 100%, preferably 90% to 100% of measured at an almost water-filled storage space (3) and an almost empty buffer space (9);

- the hardened porous water-draining concrete has one or more zones with increased water permeability compared to the average water permeability of the hardened porous water-draining concrete, said zone or zones (10) lying / lying 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 better to regulate the drainage of rainwater.

At normal rain intensities, the water that flows into the water tank is drained to the stream with a slight delay. In that case, the storage space is only partially used. In heavy rain showers, the storage space and the buffer space are almost full. The water flow that is discharged to the stream is almost limited by the passage of the outlet opening (5). The storage space acts as the first means to regulate / regulate the flow of rainwater to the stream, canal, canal, river, etc. As soon as that storage space is full, the buffer space acts as an additional storage space and buffer for rainwater;

- the volume ratio storage space (3) / buffer space (9) of the water tank (T) is greater than or equal to 2, preferably greater than 5, and most preferably between 5 and 20;

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- the porous concrete vertical inner wall (s) (8) of the water tank (T) defines / define a porous surface facing the storage area (3), the ratio storage volume (3) in m ³ / porous area in m ² is between 0.5 and 1.5;

- the outlet opening (5) for draining rainwater has a passage that is suitable for limiting the water discharge flow through that outlet opening (5) between 1 and 201 liters / s and preferably to a maximum of 51 liters / s (which outlet can optionally provide with a valve or valve mechanism to limit the water discharge flow, for example to 1; 2; 3; 4; 5; 10 liters / s);

- The buffer system has an outlet opening (5) for draining rainwater, where as long as the water level in the storage space (3) is lower than a maximum water level, the outlet opening (5) is provided with a passage system that is suitable for draining the water limit outlet opening (5) between 1 and 201 liters / s and preferably to a maximum of 51 liters / s. The passage system comprises a porous concrete element with an inner chamber which is connected to the outlet opening (5) via a pipe system. The porous concrete element is at least partly made of a hardened porous water-draining concrete, which is manufactured by hardening a mixture of at least cement, aggregates with particle size from 6mm to 14mm, and water to an open pore volume of 8 to 12% obtained in the hardened porous water-draining concrete;

- The water tank has a virtually vertical porous concrete inner wall that divides the inner 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 via a connecting pipe to a buffer tank (BT), said connecting pipe being at a level above the bottom of the buffer space (9) and above the bottom of the buffer tank (BT). The buffer tank is one

BE2019 / 0054 spout opening (50) located above the bottom of the buffer tank (BT), the spout opening (50) being provided or connected to a passage system suitable for limiting the water discharge flow through that spout opening (50) between the 1 and 201 liters / s, and preferably up to a maximum of 51 liters / s, the passage system comprising a porous concrete element with an inner chamber connected via a pipe system to the outlet opening (50), and wherein the porous concrete element is at least partially manufactured from a hardened porous water-draining concrete that is manufactured by hardening a mixture of at least cement, aggregates with particle sizes from 6mm to 14mm, and water to obtain an open pore volume of 8 to 12% in the hardened porous water-draining concrete . The passage system is preferably located in the buffer tank (BT);

- The porous concrete element takes support 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 top, and wherein, preferably, the pipe system is equipped with an overflow system to drain water as soon as the water level in the buffer space or in the buffer tank exceeds an upper level;

- the water tank or the water tank of the buffer system is equipped 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) level (H3A) of that 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) of the level (H9A) of that second overflow ( 9A) exceeds;

- the first overflow (3A) is at least partly at a level (H3A) which is below the lowest level (H9A) of the second overflow (9A). Those two overflows can drain water to the same drain pipe to a stream or river;

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- the first overflow (3A) has a passage area which is larger than the passage area of the second overflow (9A);

- the porous concrete vertical inner wall (s) (8) has / have a top side (8B) that is at a level (H8B) that is higher than the bottom edge of the first landing (3A) and the bottom edge of the second landing (9A) ). This is to prevent water from flowing above the top of the inner wall;

- at least one porous concrete vertical inner wall (8) is movable and / or removably mounted relative to the water tank, whereby a bottom edge (8X) of the inner wall can rest on the bottom of the water tank (T). This is advantageous for the installation and / or maintenance work;

- the water tank has a removable lid with manhole;

- 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 of a storage space (3), the first buffer space (90) collecting water from the storage space (3) via a partially horizontal porous concrete wall (80), and at least a second buffer space (9) cooperating with a substantially vertical porous concrete wall (8) to collect water from the storage space (3), and characterized in that the first buffer space ( 90) and the second buffer space (9) are connected by a tube or channel (100), which is preferably located along the bottom of the water tank;

- said first buffer space (90) and second buffer space (9) are connected by means of a tube or channel (100) with a top edge (100A) which has an inclination with respect to a horizontal plane, whereby said top edge (100A) the direction to the second buffer space (9) increases;

- the water tank (T) has at least two separate storage spaces (3.30),

BE2019 / 0054 in which the two separate storage spaces (3,30) are connected via an overflow pipe (31) which is intended to pass water from a first storage space (3) to a second storage space (30), as soon as the first storage space (3 is virtually water-filled, the second storage space (30) being provided with an overflow (3A) located at a level below the overflow pipe (31);

- the inlet opening (4) is equipped with a system, so that if the rainwater flow rate that flows into the tank through the inlet opening (4) is less than a certain flow rate, the system is suitable to directly drain at least part of the rainwater flow rate feeding to the buffer space;

- combinations of two or more of these details and features.

The invention also relates to the use of one or more buffer systems according to the invention for regulating water flows and / or water levels in streams and / or rivers and / or canals and / or flood areas by regulating / regulating discharge flows of rainwater originating from roofs, driveways and roadways and / or water from a canal, stream, canal or river, in which rainwater and / or water flows to storage spaces of one or more buffer systems according to the invention, and wherein this rainwater and / or water flows through porous vertical concrete walls from the water tank (s) flows into its buffer spaces before being discharged to streams and / or rivers and / or canals and / or flood areas.

Specific embodiments of the invention will now be described as advantageous examples of the invention. In that description reference is made to the attached drawings.

In those drawings, show:

fig. 1 shows a top view of a first embodiment of a buffer system (water tank T) according to the invention,

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fig. 2 shows a view of the water tank of fig. 1 in section along the line II-II,

fig. 3 shows a top view of a second embodiment of a water tank according to the invention,

- Figures 4 to 6 are cross-sectional views of the water tank of Figure 3 taken along lines IV-IV, V-V and VI-VI respectively,

- Fig. 7 shows a detail view of the water tank of Fig. 3,

fig. 8A and fig. 8B are views of a detail of an inlet opening for a water tank according to the invention,

- Fig. 9 shows a view of two water tanks connected together by pipes,

fig. 10 is a vertical sectional view of a third embodiment according to the invention,

fig. 11 is a sectional view along the line XI-XI in fig. 10,

fig. 12 shows a top view of a fourth embodiment which is the same as the embodiment of fig. 3,

- fig. 13 is a sectional view along the line XIII-XIII in fig. 12, - fig. 14 is a view of a part of an inspection path along a canal or canal, with a series of water tanks according to the invention, - fig. 15, a top view of a fourth embodiment, fig. 16 is a sectional view along line XVI-XVI in fig. 15, fig. 17 is a top view of a fifth embodiment of a buffer system according to the invention,

fig. 18 is a sectional view along line XVIII-XVIII in fig. 17, fig. 19 is a top view of a sixth embodiment of a buffer system according to the invention,

FIG. 20 is a sectional view taken along line XX-XX in FIG. 19, and FIG. 21 is a sectional view of a seventh embodiment.

Fig 1 shows a water tank (T) for collecting and storing rainwater. That water tank includes:

- one or more outer walls (1) which are / are made of non-porous concrete and which define a tub with an inner volume (2), part of which serves as storage space (3) with a storage volume for rainwater;

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- an inlet opening (4) along which rainwater can flow into the storage space (3);

- an outlet opening (5) for draining rainwater from the water tank (T);

- a lid (6) with a manhole (7); and

- a control system (5.8) to check the drainage flow of rainwater from the water tank (T).

The control system (5.8) consists of one or more porous concrete vertical inner walls (8) extending in the inner volume (2) of the water tank (T), in order to split this inner volume at least in a rainwater storage space (3) , and a buffer space (9) with a buffer volume to collect water flowing through the porous concrete vertical interior wall (s) (8).

The buffer space (9) is provided with the outlet opening (5) for draining rainwater. This outlet opening is located along the bottom of the tub (T).

The porous concrete inner wall (8) is made with special draining concrete to obtain an adapted water permeability. The draining concrete has a minimum water permeability of 0.05 liter / m ² / s and a maximum water permeability of 0.1 liter / m ² / s to 5 liters / m ² / s, preferably of 0.1 liter / m ² / s to 1 liter / m ² / s, such as 0.2 to 0.75 liters / m ² / s. The minimum water permeability is preferably from 0.2 to 0.5 liter / m ² / s.

The water permeability of that vertical porous inner wall has been measured at a storage space (3) that is virtually water-filled, while the buffer space is virtually empty. For that measurement

BE2019 / 0054, for example, a pump is used to keep the buffer space almost empty.

One can also determine the maximum water permeability of the draining concrete by drawing up a porous concrete slab that serves as the bottom of a test vessel. The test vessel (with a height equal to the height of the tank) will be filled with water afterwards, and the water flow rate will be measured for the water that flows through the porous soil.

The draining concrete is preferably manufactured by allowing a mixture of at least cement, aggregates and water to harden, in order to obtain a total open pore volume of 8 to 12% in the hardened concrete. Aggregates with a particle size of 6mm to 14mm are preferably used for the concrete. Preferably, the draining concrete granulates contain 15% by weight granulates with a particle size greater than 8mm, while the water / cement weight ratio is less than 0.5, ideally between 0.35 and 0.42.

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

The uncured concrete mixture (without water) can contain up to 15% by weight of sand, with a size smaller than 4mm, for example with a size of 2 - 4mm. The sand is preferably round-grained and, for example, sand comes from a river. Examples of sand contents are 2; 5; 8; 10; 12% by weight.

To better control the water permeability of the concrete, one or more additives can be added to the uncured concrete mixture, such as aqueous polymer dispersion, in particular acrylate / methacrylate polymer / copolymer aqueous dispersion, such as copolymer of acrylic acid ester-vinyl ester aqueous

BE2019 / 0054 dispersion. For example, 10 to 30% by weight of polymer dispersion can be added to the concrete, the weight percentage being measured relative to the cement weight.

The water tank has a height (H) of less than 3m, such as from 2 to 2.5m.

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

In its first embodiment (fig 1), the total water discharge capacity varies linearly with the water height present between 0% and 100%.

In a second embodiment, the total water discharge capacity is measured at a water height of half of the storage space, and preferably at a water height of 0.3 m, equal to 80% to 100%, preferably 90% to 100% of this measured at a storage area almost completely filled with water (3).

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

In the embodiment of Fig. 3, the porous concrete has multiple zones (10) with increased water permeability relative to the average water permeability of the porous concrete. Those zones (10) are in the vicinity of the bottom, for example at a height (h) of the bottom (3B) of the storage space (3) which is less than 50 cm, and preferably less than 30 cm.

Those zones (10) can be produced using elevated size aggregates. These zones can also form an intermediate layer in the porous wall, the intermediate layer being at a height between 20 and 50 cm relative to the bottom (3B).

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

The porous concrete inner wall (8) defines a porous surface facing the storage area (3), where the storage volume (3) ratio in m ³ / porous surface area in m ^{2 is} between 0.5 and 1.5 (such as between 0, 7 and 1.25, preferably 0.8; 0.9; 1; 1.1 and 1.2). This ratio provides a good control of the maximum flow rate of water flowing through the porous wall, and a sufficient storage volume for rainwater.

The rainwater drainage outlet (5) has a passage suitable for limiting the water discharge flow through said drainage outlet (5) between 1 and 201 liters / s and preferably to a maximum of 51 liters / s.

The water tank is equipped with at least two separate overflows (3A, 9A), namely a first overflow (3A) for the storage space (3) for draining rainwater from the storage space, as soon as the water level in the storage space (3) reaches the level (H3A ) of that first overflow (3A), and a second overflow (9A) for the buffer space (9) for draining rainwater from the buffer space, as soon as the water level in the buffer space (9) exceeds the level (H9A) of that second overflow (9A).

Via these overflows 3A, 9A, two water tanks T, T1 according to the invention can be bound together by pipes 20, 21. For example, the tank T1 is located at a lower level relative to the tank T, allowing water to flow freely from tank T to tank Tl. The overflow opening 3A of the tank T is connected to the inlet opening 4 of the tank T1 via the pipe 20. As soon as the storage space 3 of the tank T is full, water flows from that storage space 3 to the storage space 3bis of the tank T1. (see fig 9)

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The overflow 9A of the buffer space 9 of the tank T is with an inlet 40 via the pipe 21. In case the buffer space 9 of the tank T is almost full, water flows from the buffer space of the tank T to the buffer space 9 of the tank Tl. Water is drained from the buffer spaces 9 of tanks T and T1 to the stream S via pipes 22.

The first overflow (3A) is at least partly at a level (H3A) above the lowest level (H9A) of the second overflow (9A).

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

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

The porous concrete inner wall (8) has a top (8B) that is at a level (H8B) higher than the bottom edge of the first landing (3A) and the bottom edge of the second landing (9A). This is advantageous to prevent water from flowing above the inner wall of the storage space to the buffer space 9.

In the shown embodiment of fig. 1, the lid 6 is removably mounted on the tub 1. In that case, it is also advantageous to mount the porous concrete inner wall 8 removably in the tub. The bottom edge of the wall 8 rests on the bottom of the tub, possibly with a rubber intermediate piece.

Via the manhole 7, one can have a view of the water level in both rooms (3.9). Maintenance work can also be carried out via that manhole in the cockpit.

In the embodiment of Fig. 3, the water tank comprises three or more than three separate buffer spaces (9,90,91), namely (a) at least one first and second buffer spaces (90, 91) running along the

BE2019 / 0054 bottom of a storage space (3), said first and second buffer spaces (90) collecting water from the storage spaces (3,30) via an at least partly horizontal porous concrete wall (80,81), and (b) at least a third central buffer space (9) which interacts with two substantially 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 tub can be maintained via fasteners (rods 111).

The first and second buffer spaces are connected to the third buffer space (9) by pipes (100) located along the bottom of the water tank. Those tubes 100 show an inclination with respect to a horizontal plane, so that the top edge (100A) of those tubes rises in the direction of the third buffer space (9). In this way, air or gas can be prevented from remaining in the buffer spaces 90, 91, which can be detrimental to the passage of water.

The two separate storage rooms (3.30) are connected via an overflow pipe (31). Said pipe 31 is intended to drain water from the first storage space (3) to the second storage space (30), as soon as the first storage space (3) is virtually water-filled, the second storage space (30) being provided with an overflow (3A ) located at a level below the overflow pipe (31).

In a possible embodiment, the inlet opening (4) can be provided with a control system 100, so that if the rainwater flow rate flowing into the tank T is less than a certain flow rate, the system 100 is suitable to directly drain at least part of the rainwater flow rate to be fed to the buffer space 9. With such a system, for a short and non-stormy rainy period, the rainwater can be partly discharged to the storage space 3, and partly to the buffer space.

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Such a system is shown in Figures 8A and 8B. The rainwater W flows into a chamber 101 which is provided with an open inner vessel 102 to collect at least part of the rainwater. The bottom of this vessel is provided with a hole 102A. Within this vessel, a float 103 moves with a surface 103A acting as a valve system. The inner vessel 102 communicates 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 102. Since the flow is not sufficient, the float 103 remains in a lower position, whereby part of the rain flows directly to the buffer space 9, while another part flows to the storage space 3 via the opening 102A. (see Fig 8A).

In case of storm rain, the water level in the inner vessel rises, leaving the float 103 in closed position to seal the inlet of the pipe 41. In such a closed position, almost all rain flows into the storage space of the tank T.

A third embodiment of a water tank according to the invention is shown in Fig. 10.

The tank T contains a concrete tank (watertight) with a spout 5 along the bottom 1B. Along the bottom IB, the tank is provided with one or more support elements 1C for a slab 80 of porous concrete. The round plate 80 is supported or the support elements 1C. Above plate 80 there is cylindrical pipe 82 made of porous concrete.

The plate 80 can optionally be provided with a hole 80G to connect the buffer zones 9,90 together. If that plate 80 is not provided with the hole 80G, the buffer spaces are connected through the open pores of the plate 80.

The cylindrical pipe 82 can preferably be placed in the tank via the manhole 7. The correct placement of the pipe

BE2019 / 0054 can be obtained via intermediate elements 110 which are located between the top edge of the pipe 82 and the bottom surface of the lid.

Figures 12 and 13 are views of an embodiment similar to the embodiment of Figures 3 to 6 unless a few modifications.

The tub and / or the vertical porous walls 8,8bis are provided with support elements 1C for porous plates 80, 81. The position of the plates on the support elements 1C is maintained by using fasteners 111, which for example are partly in a wall of the tub are fitted.

Fig. 14 is a view of a moat or channel 200, with a dam 201 and two inspection paths 202,203. Several water tanks have been installed along the inspection path 203 according to the invention. The water tank 1 is connected to the channel 200 via the pipe 204. The storage spaces of the water tanks 1, Ibis, Iter, etc. are connected, so that water can be drained from the storage space of tank 1 to the storage space of tank Ibis, as soon as the water level in storage space 3 of tank 1 exceeds a certain level.

The outlets 5 of all tanks 1, Ibis, etc. are in communication with an outlet pipe 205 to drain water back into the channel, after dam 201.

The water tanks according to the invention can thus be used to control the water level in the channel. As soon as the water level exceeds a maximum level, the water tanks 1, Ibis, etc. can collect water from the channel, and be drained back into the channel with a delay, providing a solution against storm water (with heavy rain in a short time).

Since the water tanks may be located under inspection paths, the construction of those tanks can be carried out with the construction of those inspection paths.

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

In the embodiment of Fig. 15 and Fig. 16, the buffer system includes a rectangular tank T with a vertical porous concrete inner wall (8), which divides the inner volume of the tank into a storage space (3) and a buffer space (9).

The tank T is also provided with an inlet opening (4) at a level higher than the upper level of the inner wall (8), whereby in case of storm water, water can flow directly into the buffer space (9). Storm water can then be discharged via an overflow pipe (51) which is connected to the outlet opening (5).

The outlet opening (5) is connected to a porous concrete element (85) via a horizontal pipe (86) (which is spaced from the bottom of the buffer space). The porous concrete element (85) defines an inner chamber (87) (to collect water which is connected to the outlet opening (5) via a pipe system (86) through the porous walls of the element (85). The porous concrete element is at least partly made of a hardened porous water-draining concrete, which is manufactured by hardening a mixture of at least cement, aggregates with particle size from 6mm to 14mm, and water to an open pore volume of 8 to 12% obtained in the hardened porous water-draining concrete.

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

The embodiment of Figures 17 and 18 is similar to the embodiment of Figures 15 and 16. The buffer system of Figures 17 and 18 includes a water tank (T), the buffer space of which is connected to a buffer tank (BT) by a connecting pipe 55. The connecting pipe 55 is at a level above the bottom of the

BE2019 / 0054 buffer space (9) of the tank T and of the bottom of the buffer tank (BT).

The buffer tank is provided with an outlet opening (50) located above the bottom of the buffer tank, the outlet opening (50) being connected to a passage system which is suitable for limiting the water discharge flow through that outlet opening (50) between 1 and the 201 liters / s and preferably up to a maximum of 51 liters / s. The passage system includes a porous concrete element (85) with an inner chamber (87) connected to the outlet opening (50) via a tubing system (86). The porous concrete element is at least partly made of a hardened porous water-draining concrete, which is manufactured by hardening a mixture of at least cement, aggregates with particle size from 6mm to 14mm, and water to an open pore volume of 8 to 12% obtained in the hardened porous water-draining 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) containing one or more porous walls, as well as a porous top, and wherein, preferably, the pipe system 86 is provided with an overflow system (pipe 51) to drain water as soon as the water level in the buffer space (9) or in the buffer tank (BT) exceeds an upper level (for example the level of the inner wall (8)).

The buffer system of Figures 19 and 20 is similar to the buffer system of Figures 17 and 18, except that the pipe 51 is connected to the inner chamber (87) of the porous element (85).

Fig. 21 shows a multi-tank buffer system T1, T2, etc. to collect rainwater, which are connected together. These tanks are therefore connected to a buffer system according to the invention to control the water discharge (water tank (T) with porous vertical inner wall (8) and buffer tank (BT) with element (85)).

Claims (13)

CONCLUSIONS Rainwater / water buffer system containing at least one water tank (T) for collecting rainwater / water, the water tank (T) comprising at least: - one or more outer walls (1) which is / are made of non-porous concrete and which defines an inner volume (2), part of which serves as storage space (3) with a storage volume for rainwater / water; - an inlet opening (4) along which rainwater / water can flow into the storage space (3); - an outlet opening (5) for draining rainwater / water from the water tank (T); - a lid (6) with a manhole (7); and - a control system (5.8) to control the drainage flow of rainwater from the water tank (T), characterized in that the control system (5.8) consists of at least one or more porous concrete vertical inner walls (8) extending in the inner volume (2) of the water tank (T), and which divides this inner volume at least into a storage space (3) for rainwater / water, and a buffer space (9) with a buffer volume to collect water flowing through the porous concrete vertical inner wall (s) (8) flows, characterized in that the buffer space (9) is provided with the outlet opening (5) for draining rainwater / water, and characterized in that the porous concrete vertical inner wall (s) (8) is manufactured is / are of a hardened porous water-draining concrete which is manufactured by hardening a mixture of BE2019 / 0054 at least cement, aggregates with particle size from 6mm to 14mm, and water to obtain an open pore volume of 8 to 12% in the hardened porous water-draining concrete, where the hardened porous water-draining concrete has a water permeability of 0.05 liter / m ² / s to 5 liter / m ² / s, preferably from 0.1 liter / m ² / s to 3 liter / m ² / s, preferably between 0.1 and 1 liter / m ² / s, in which the water permeability was measured at an almost completely water-filled storage space (3) and an empty buffer space (9). Buffer system according to claim 1, wherein the water tank (T) has a height (H) of less than 3m, characterized in that the total water discharge capacity measured at water height of half of the storage space (3), and preferably also at a water height of 0.3m in the storage space (3), equal to 80% to 100%, preferably 90% to 100% of this measured at an almost completely water-filled storage space (3). Buffer system according to claim 1 or 2, characterized in that the hardened porous water-draining concrete has one or more zones with increased water permeability compared to the average water permeability of the hardened porous water-draining concrete, said zone or zones (10) lying / lying at a height (h) from the bottom (3B) of the storage space (3) that is less than 50 cm, preferably less than 30 cm. Buffer system according to any one of the preceding claims, characterized in that the volume ratio storage space (3) / buffer space (9) for the water tank (T) is greater than or equal to 2, preferably greater than 5, and most preferably between 5 and 20 . Buffer system according to any one of the preceding claims, characterized in that the porous concrete inner wall (s) (8) of the water tank (T) defines / defines a porous surface facing the storage space (3), the ratio of storage volume ( 3) in m ³ / porous surface in m ^{2 is} between 0.5 and 1.5. BE2019 / 0054 Buffer system according to any one of the preceding claims, characterized in that the buffer system has an outlet opening (5) for draining rainwater, wherein the outlet opening (5) is provided as long as the water level in the storage space (3) is lower than a maximum water level. with a passage system suitable for limiting the water discharge through that outlet opening (5) between 1 and 201 liters / s and preferably to a maximum of 51 liters / s, the passage system comprising a porous concrete element with an inner chamber which pipe system is connected to the outlet opening (5), and wherein the porous concrete element is at least partly made of a hardened porous water-draining concrete which is manufactured by hardening a mixture of at least cement, aggregates with particle size of 6mm to 14mm, and water to obtain an open pore volume of 8 to 12% in the hardened porous water-draining concrete. Buffer system according to any one of the preceding claims, characterized in that the water tank is provided with an almost vertical porous concrete inner wall (8) which divides the inner volume of the water tank into a storage space (3) and into a buffer space (9), wherein the buffer space (9) of the water tank (T) is connected via a connecting pipe to a buffer tank (BT), said connecting pipe located at a level located above the bottom of the buffer space (9) and above the bottom of the buffer tank, and the buffer tank being provided with an outlet opening (50) located above the bottom of the buffer tank, the outlet opening (50) being provided or connected to a passage system suitable for limiting the water discharge flow through said outlet opening (50) 1 and 201iter / s and preferably up to a maximum of 51iter / s, the passage system comprising a porous concrete element with an inner chamber connected to the outlet opening (50) via a pipe system, and wherein the porous concrete element is at least partially made of a hardened porous water-draining concrete which is made by hardening a mixture of cement, aggregates with particle sizes from 6mm to 14mm, and water to form a BE2019 / 0054 24 open pore volume of 8 to 12% to be obtained in the hardened porous water-draining concrete. Buffer system according to claim 6 or 7, characterized in that the porous concrete element rests on the bottom of the buffer space (9) or of the buffer tank (BT), wherein the porous concrete element contains one or more porous walls, as well as a porous top, and wherein, preferably, the pipe system is provided with an overflow system for draining water as soon as the water level in the buffer space or in the buffer tank exceeds an upper level. Buffer system according to any one of the preceding claims, characterized in that the water tank or the water tank with buffer tank is provided with two separate overflows (3A, 9A), namely a first overflow for the storage space of the water tank for draining rainwater as soon as the water level in the storage space (3) exceeds the level (H3A) of that first overflow (3A), and a second overflow (9A) for the buffer space (9) or for the buffer tank (BT) for draining rainwater as soon as the water level in the buffer space (9) or in the buffer tank (BT) exceeds the level (H9A) of that second overflow (9A). Buffer system according to any 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) located along the bottom of a storage space (3), said first buffer space (90 ) collects water from the storage space (3) via an at least partially horizontal porous concrete wall (80), and at least a second buffer space (9) which interacts with a substantially vertical porous concrete wall (8) to collect water from the storage space (3) and characterized in that the first buffer space (90) and the second buffer space (9) are connected by a tube or channel (100), which is preferably located along the bottom of the water tank. BE2019 / 0054 Buffer system according to claim 10, characterized in that the water tank (T) has at least two separate storage spaces (3,30), said two separate storage spaces (3,30) being connected via an overflow pipe (31) intended for water by passing 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 level located under the overflow pipe (31). Buffer system according to any one of the preceding claims, characterized in that the inlet opening (4) is provided with a system, so that if the rainwater flow rate flowing into the tank through the inlet opening (4) is less than a certain flow rate, the system is appropriate is to drain at least part of the rainwater flow directly to the buffer space (9) of the water tank. Use of one or more buffer systems according to any one of the preceding claims for regulating water flows and / or water level in streams and / or rivers and / or canals and / or flood areas by regulating discharge flows of rainwater from roofs, driveways and road conditions. and / or water originating from a channel, stream, moat or river, wherein rainwater and / or water flows to storage spaces of one or more buffer systems according to any one of the preceding claims, and wherein this rainwater and / or water flows through porous concrete vertical walls of the water tank flows through to its buffer spaces, before being discharged to streams and / or rivers and / or canals and / or flood areas.