WO2015049639A2

WO2015049639A2 - Floor for a gravity filter with a filter medium for the treatment of water, and casing for such a floor

Info

Publication number: WO2015049639A2
Application number: PCT/IB2014/064981
Authority: WO
Inventors: Nicolas PETROFF; Pascal TROLES; David RATTE
Original assignee: Degremont
Priority date: 2013-10-02
Filing date: 2014-10-01
Publication date: 2015-04-09
Also published as: WO2015049639A3; FR3011189A1; FR3011189B1

Abstract

The invention relates to a floor for a gravity filter with a filter medium for the treatment of water, comprising casings (3) arranged on an invert (4) and supporting at least one layer (N) of granular filter medium, each casing comprising an upper wall provided with openings (6) for the passage of filtered water, or washing water and/or air. Each casing (3) has an inner section free of any walls, and is completely closed at one end while its opposite end is partially closed and comprises a water inflow/outflow opening in the lower part, and an air inflow opening in the upper part, and the openings (6) of the upper wall of the casing are provided with nozzles (11) for ensuring a relatively uniform distribution of the flows of fluid.

Description

P T / IB2014 / 064981

1

FLOOR FOR FILTER GRAVITAI RE A MEDIA FILTER FOR WATER TREATMENT, AND BOX FOR SUCH FLOOR.

The invention relates to a floor for gravity filter with filter media, for the treatment of water, a floor of the type of those comprising caissons arranged on a floor and supporting at least one layer of granular filter media, each box comprising a upper wall provided with orifices for the passage of filtered water, or water and / or washing air.

Coffered floors can be used in place of relatively long concrete floors.

EP 0 562 182 proposes a drain, or box, prefabricated to produce such floors. The drains are connected end to end with establishment of a seal seal between two drains that follow. The drains are anchored to the base of the filter, after casting a mortar of first phase, to form continuous ramps. The internal structure of a drain has a plurality of internal walls to define chambers for the flow of water and washing air. The arrangement of the internal walls is intended to homogenize the pressures and, as far as possible, to ensure a uniform distribution of the fluid flow rates through the orifices of the upper wall of the box. This complex internal structure of drains results in high manufacturing costs. In addition, the installation requiring the sealed assembly of several drains end to end is relatively long and expensive. In addition, it is desirable that the uniformity of the distribution of the flow of washing fluid through the openings of the upper wall of the boxes is improved.

The object of the invention is, above all, to provide a floor of the kind defined above which is of a more economical and rapid embodiment, while ensuring a good distribution of the flow of the washing fluids through the orifices of the upper wall. caissons.

According to the invention, a filtering medium gravity filtering floor for water treatment, of the kind defined above, is characterized in that each box has an inner section free of any wall, is completely closed at one end while its end opposite is partially closed and has a water inlet / outlet at the bottom, and an air inlet at the top, and in that the orifices of the upper wall of the box are equipped with clean bushings to ensure a relatively uniform distribution of fluid flows.

The boxes are in one piece. Modular box assemblies are avoided. In the case of a rectangular floor, the caissons extend along an entire dimension of the floor, the length of the boxes being equal to said dimension of the floor, or along half of said dimension, each box having a length equal to said half-size, and two boxes being arranged head to tail , with their adjacent open ends.

Preferably, the boxes are arranged with their length oriented parallel to the width of the floor.

The inner section of a box being free, this box can be made by extrusion, quickly and economically.

Advantageously, the cross section of the boxes is rectangular. Preferably, the boxes are directly placed on a bed of mortar of first phase parallel to each other, being separated by a reduced space, preferably between 50mm and 00mm. A second phase mortar is poured into the space between the caissons.

For each box, the water inlet / outlet orifice, located in the lower part of an end wall, has a passage section which may be between 120 and 160 cm ² , preferably about 140 cm ² , while the air inlet port, located in the same end wall at the top, has a section of about 13 cm ² .

Connecting pieces between the water inlet and outlet ports of the caissons can be sealed in a water inlet and wash air channel provided on one side of the filter.

The invention also relates to a gravity filter floor box of the kind defined above, this box comprising an upper wall provided with orifices for the passage of filtered water or washing, and / or washing air, and characterized in that it has an inner section free of any wall, is completely closed at one end, while the opposite end is partially closed and has a water inlet / outlet at the bottom, and an air inlet at the top, and in that the orifices of the upper wall of the box are equipped with nozzles, capable of ensuring a relatively uniform distribution of fluid flow rates.

Advantageously, the box is made of composite material, in particular with isophthalic resin, in accordance with the requirements of the standards relating to materials put in contact with water intended for human consumption.

The upper surface of the box has a uniform distribution of orifices receiving the bushings. These bushings allow the passage of water filtered during the filtration step, and the passage of water and / or washing air during the washing step of the filter media. The distribution of the openings of the upper wall, and therefore of the nozzles, is optimized so as to ensure an ideal and uniform distribution of water and air during the countercurrent washing step.

The lateral surfaces of the box are advantageously equipped with at least one fin, which reinforces the seal in the mortar. The fins fitted to the lateral surfaces are preferably arranged at different heights to facilitate attachment in a second phase mortar. The lower surface of the box can also be equipped with at least one fin to reinforce the seal in a first phase mortar.

The dimensions of the boxes are adjustable to fit any filter surface. The length can be between 1 meter and 5 meters, the width between 300 and 400 mm, and the height between 200 and 400 mm.

The box is advantageously obtained by extrusion of a blank cut to the desired length, which generally corresponds to a dimension, width or length, or to half of said dimension, of a rectangular filter floor. The two open ends of the box blank are then closed by a bonded or welded end transverse wall, and one of the end walls is pierced for the realization of the water inlet / outlet port. , and the one for the entry of the washing air.

The invention also relates to a method of constructing a gravity filter floor, of the kind defined above, in which the boxes are directly placed on the base of the filter without anchoring, being separated by a reduced space, preferably included between 50mm and 100mm, after pouring of a first phase mortar bed and, after the caissons have been laid, a casting of a second phase mortar is made between the caissons.

After pouring the second phase mortar, the layer or layers of filter media are spread on the caissons equipped with the bushings.

The invention consists, apart from the arrangements set forth above, in a certain shadow of other arrangements which will be more explicitly discussed hereinafter with reference to an embodiment described with reference to the appended drawings, but which is in no way limiting. On these drawings:

Fig. 1 is a partial schematic view from above of a filter floor according to the invention. Fig. 2 is a schematic section along line 11-11 of FIG. 1 of the filter.

Fig. 3 is a perspective view, on a larger scale, of a box according to the invention.

Fig. 4 is a view, on a larger scale, of the end of the box provided with orifices, and

Fig. 5 is a view, on a larger scale, of a bush which equips each orifice of the upper wall of the box.

Referring to Fig. 1 and 2, there can be seen a floor 1 of filter gravity open filter 2 formed, in particular, by a granular material including sand, for the treatment of water. The filter comprises at least one N layer of filter media. Generally several layers of different grain sizes are superimposed and supported by the floor 1.

This floor is made with boxes 3. Each box has an upper wall 5 provided with orifices 6 for the passage of filtered water from top to bottom, or for the passage of water and / or washing air, bottom up.

According to the invention, each box 3 has an inner section free of any wall, as can be seen in FIG. 2. The box 3 is made in one piece and extends parallel to one of the dimensions of the floor, generally rectangular. The length of a box is preferably equal to said dimension, width or length of the floor. Alternatively, if the dimension is high, especially greater than 5m, the length of a box is equal to half of said dimension, and two boxes are arranged head to tail along said dimension, with adjacent open ends.

Advantageously, the box 3 extends parallel to the width of the floor, the length of a box 3 up to 5 m.

Each box 3 can be made by extrusion, composite material, especially isophthalic resin, in accordance with the requirements of French and international standards relating to materials brought into contact with water intended for human consumption.

The caissons 3 are directly placed on the base 4 of the filter, without anchoring, and after casting a mortar bed 7 (FIG 2) of first phase, being separated by a reduced space J, preferably between 50mm and 100mm, especially 70mm. Once the caissons 3 are laid, as illustrated in FIG. 2, mortar 8 is poured, during a second phase, between each coffer ramp.

The cross section of a box, as shown in Figures 2-4, has a rectangular shape whose large dimension is arranged horizontally. For manufacturing, a box blank is made by extrusion and is in the form of a rectangular section prism, whose walls are solid. The box blank 3 is cut to the desired length, the two longitudinal ends of the blank being open. One end of the blank is closed by a transverse wall 3a (FIG 3), welded or sealed to the corresponding end of the casing 3. The other longitudinal end of the casing is sealed in the same manner by a transverse wall 3b.

An opening 9, in particular of rectangular shape and whose surface may be of the order of 120 to 160 cm ² is cut in the end wall 3a in the lower part of said extremity. This opening 9 is intended for the passage of water. An opening 10, of smaller section, in particular of the order of 10 to 15 cm ² , and generally of circular shape, is provided in the upper part of the end wall 3a having the opening 9. air passage when washing the filter.

The openings 9 and 10 are provided for receiving connecting pieces (not shown) which are sealed in a channel (not shown) of water and washing air. The dimensions of these connecting pieces vary according to the thickness of the wall separating the filter from the channel for air and for water.

After extrusion of the blank, the orifices 6 are made in the upper wall of this blank as shown in FIG. 3. The drilling holes 6 is formed in a uniform distribution of orifices, each orifice having a diameter to receive a nozzle 1 1 which allows the passage of water during the filtration step, from top to bottom, and the passage of water and air during the washing step of the filter media, from bottom to top.

Each nozzle 1 1 comprises a head 12a provided with vertical slots sufficiently thin to oppose the passage of the filter material, and a cylindrical shank 12b constituted by a tube open at its lower part and immersed in the water sheet E (FIG. 2) located in the lower part of the box. The shank 12b has vertical slots 12c crossing the upper level 13 of the water layer E. The upper part of the slots 12c is in the air layer A above the layer of water E. Washing air can therefore go through this upper part of the slots 12c to flow vertically upwards, mixing with water also injected from bottom to top. The nozzles 11 are sealingly attached to the upper wall 5 of the box and ensure a uniform distribution of air and wash water in the N layer of filter material. The two vertical side surfaces of each box 3 are advantageously equipped with at least one horizontal fin 14. This fin can be obtained in one piece with the blank of the box during the extrusion of this blank. The fins 14 make it possible to reinforce the sealing of the caissons 3 in the mortar 7 of the first phase, and in the mortar 8 of the second phase, and to secure all the caissons to form a single floor. The fins fitted to the lateral surfaces are preferably arranged at different heights to facilitate attachment in the second phase mortar.

The lower surface of the box may also be equipped with at least one fin 14, vertical, to reinforce the seal in the first phase mortar.

The dimensions of the caissons 3 are adjustable, so as to adapt to any filter surface:

the length L can be between 1 and 5 meters

the width W (FIG 3) can be between 300 and 400 mm

the height H can be between 200 and 400 mm.

The box 3 being in one piece and completely closed at one end, no waterproof connection is to be made unlike in the case where several drains are assembled end to end.

The floors made with boxes 3 according to the invention have many advantages.

Quick and easy installation of floors:

The civil works are greatly reduced and very simple to carry out:

- all production operations of prefabricated elements, such as slabs, beams, and reinforcement operations are avoided;

the pouring of a mortar 8 of the second phase between the caissons 3 is facilitated by a sufficient distance J between caissons;

- The laying operations of the caissons 3 are also simplified:

• these caissons being directly placed on a bed of mortar, all work anchoring boxes to the floor is avoided;

• the shape of rectangular parallelepiped boxes makes it easier to adjust and adjust the boxes to obtain the desired horizontality of the floor;

• Flatness tolerances are more easily accessible than in the case of concrete floors;

• because of the low weight per linear meter of the casing 3, these the latter can be handled manually, without the need for motorized lifting means, such as cranes;

- the control steps are reduced: it is only a question of verifying the horizontality of all the caissons, and to carry out leak tests once these caissons are assembled, in particular in the zone of connection between the caissons and a water and air inlet channel;

- finally, the implementation of the floors does not depend on the know-how or the control, by the civil engineering companies, of prefabrication techniques, and can thus be realized in many countries, without necessity of a technological level Student.

Greater reliability of the floors:

the waterproofing of the floors, with the caissons according to the invention, can be obtained more easily, and at a lower cost, than in the case of concrete floors; the sealing is indeed provided by the boxes themselves, without involving expensive joints;

- Tightness of the floors is simpler than that to be realized with manufactured drains which require to assemble several drains and to realize a seal between the assembled drains;

the material used for the manufacture of the boxes has mechanical strength properties: constant flexibility, absence of permanent deformation, dimensional stability, and chemical resistance properties, in particular resistance to corrosion, which makes it possible to obtain durability higher than for concrete floors;

- Due to the simplicity of the materials used and the structure of the boxes, they are prepared on demand, preferably by extrusion, being adapted to the dimensions of the floor to be built; according to the invention, there are no longer carrier beams in the slab, or joints or prefabricated elements. Risks of unpredictable floor construction are reduced, which limits the factors that can lead to claims.

Reduction of manufacturing and assembly costs:

Due to :

the use of a low-cost composite material;

- a box section: tube with rectangular section devoid of internal walls, much simpler than that of manufactured drains with interior walls;

- a production of standardized boxes, and a large daily volume; - an easy adaptation of the production machines, allowing to obtain a great modularity of the boxes, with variability of the length of the boxes according to the dimensions, in particular the exact width of the filters to be realized

- The low height of the boxes, which reduces the total height of the filter, while maintaining the same height of filter media. This reduction notably makes it possible to significantly reduce the civil engineering costs of filter construction.

All these characteristics make it possible to obtain lower production costs than other known floors, whether made of concrete or using manufactured plastic drains.

Reduction of manufacturing and installation times:

- the simplicity of the profile, as well as the standardization of the production operations, allow to obtain manufacturing times lower than those required for plastic drains with interior walls;

- all complex civil engineering operations are avoided: no reinforcement, no anchoring, and the deadlines for laying the caissons are also significantly lower than those encountered for the construction of concrete floors. Comparative analysis

A comparative study was carried out on the costs and construction times for a gravity open filter floor in a facility with the following characteristics:

- treatment capacity of 430.10 ⁶ liters / day;

- total filter area of 2160 m ² ;

filtration station composed of 12 double-cell filters with a surface area of 180 m ² , length = 18 m and width = 2 x 5 m.

The total cost of a station made with the caissons according to the invention was estimated to be about 20% lower than that obtained with the known techniques of reinforced concrete or manufactured drains, with a construction time of the same order as that obtained with manufactured drains and significantly lower than that of concrete floors.

Industrial applications

The invention can be applied to the construction and rehabilitation of open gravity or closed pressure filters with filter media: sand, anthracite, granular activated carbon, or other media including mixtures of these materials, for production drinking water, seawater filtration, or wastewater treatment.

Claims

9 CLAIMS

1. Floor for gravity filter with filtering media, for the treatment of water, comprising caissons arranged on a base and supporting at least one layer of granular filter media, each box comprising an upper wall provided with orifices for the passage of water. filtered water, or water and / or washing air, characterized in that each box (3) has an inner section free of any wall, is completely closed at one end (3b) while its opposite end (3a) ) is partially closed and has a water inlet / outlet port (9) at the bottom, and an air inlet (10) at the top, and that the orifices (6) of the upper wall of the box are equipped with nozzles (11) capable of ensuring a relatively uniform distribution of fluid flows.

2. Floor according to claim 1, characterized in that the boxes (3) are in one piece.

3. Rectangular floor according to claim 1 or 2, characterized in that the boxes (3) extend along an entire dimension of the floor, the length of the boxes being equal to said dimension of the floor, or along half of said dimension, each box having a length equal to said half-size, and two boxes being arranged head-to-tail, with their adjacent open ends.

4. Floor according to claim 3, characterized in that the boxes (3) are arranged with their length oriented parallel to the width of the floor.

5. Floor according to any one of the preceding claims, characterized in that the boxes are directly placed on a bed (7) of first phase mortar parallel to each other, being separated by a reduced space (J), preferably between 50mm and 00mm, a mortar (8) of second phase being poured into the space between the boxes.

6. Casing for gravity filter floor according to any one of the preceding claims, comprising an upper wall provided with orifices for the passage of filtered water or washing, and / or washing air, characterized in that it has an inner section free of any wall, is completely closed at one end (3b), while the opposite end (3a) is partially closed and has a water inlet / outlet port (9) at the bottom, and an air inlet (10) at the top, and in that the orifices (6) of the top wall of the box are equipped with nozzles (1 1), able to ensure a relatively uniform distribution of fluid flows.

7. Casing according to claim 6, characterized in that it is made of composite material, in particular with isophthalic resin, in accordance with the requirements of the standards relating to the materials in contact with water intended for human consumption.

8. Box according to claim 6 or 7, characterized in that the side surfaces of the box (3) are equipped with at least one fin (14), which reinforces the seal in the mortar.

9. Housing according to claim 8, characterized in that the fins (14) fitted to the side surfaces are arranged at different heights.

10. Box according to claim 8 or 9, characterized in that the lower surface of the box (3) is equipped with at least one fin (14), which reinforces the seal in the mortar.

1 1. Casing according to any one of claims 6 to 10, characterized in that it is obtained by extrusion of a cut blank to the desired length, the two open ends of the box blank being then closed by a transverse wall of end is glued or welded, and one of the end walls is pierced for the production of the water inlet / outlet (9), and the one (10) for the inlet of the air washing.

12. A method of constructing a gravity filter floor, according to any one of claims 1 to 5, characterized in that the boxes (3) are directly placed on the base (4) of the filter without anchoring, being separate by a reduced space, preferably between 50mm and 100mm, after casting a mortar bed (7) of the first phase and, after the casings have been laid, a casting of a mortar (8) of the second phase is realized between the caissons.