WO2016193511A1

WO2016193511A1 - Granular matrix filter

Info

Publication number: WO2016193511A1
Application number: PCT/ES2016/070369
Authority: WO
Inventors: Josep Bové Masmiquel; Gerard Arbat Pujolràs; Jaume Puig I Bargués; Toni Pujol Sagaró; Miquel Duran Ros; Francisco Ramírez De Cartagena Bisbe; Joan Pujol Planella
Original assignee: Universitat De Girona
Priority date: 2015-05-29
Filing date: 2016-05-17
Publication date: 2016-12-08
Also published as: ES1139983Y; ES1139983U

Abstract

Disclosed is a granular matrix filter (1) for filtering a fluid, which comprises: an inner chamber (2) having a inlet (4) and a permeate outlet (6); a first drain (8) that covers the outlet (6); and a first granular filtering means (12) through which the fluid passes. The granular matrix filter further comprises a second granular filtering means (14) disposed in the chamber (2) between the first filtering means (12) and the first drain (8). The second filtering means (14) has greater permeability than the first filtering means (12). The filter (1) has a second drain (10), disposed so as to physically separate the first and second filtering means (12, 14), the second drain (10) comprising a plurality of holes for the passage of fluid that are smaller than the granulometry of the first filtering means (12). Lastly, the first drain (8) comprises a plurality of holes for the passage of fluid that are smaller than the granulometry of the second filtering means (14).

Description

GRANULAR MATRIX FILTER

DESCRIPTION

Field of the Invention

The invention relates to a granular matrix filter for filtering a fluid comprising an inner chamber with a fluid inlet to be filtered and a permeate outlet, a first drain covering the permeate outlet, and a first filter media , granular, arranged in said chamber to be traversed by said fluid when circulating between said inlet and outlet.

State of the art

Filtration is an indispensable operation in various applications in which it is of interest to eliminate suspended solids, such as water treatments for purification or purification or to prevent the clogging of emitters in drip irrigation facilities. . The filters with the best performance in removing solids in suspension are those of granular matrix.

A known filter 100 very common in the state of the art and represented in Figures 1 to 3 which is formed by an inner chamber 102 with an upper fluid inlet 104 that must be filtered and a lower permeate outlet 106, separated from each other. by a granular filter means 12 disposed in the chamber 102 which is flowed through the fluid as it circulates between the inlet and the outlet. The permeate outlet is carried out in a drain, called crepine 108. As can be seen in figures 1 to 3, the crepe 108 consists of a conical plastic dome with various longitudinal slots 1 10 opening smaller than the particle size of the filter medium 1 12 that allow the permeate to pass through. The conical dome is mounted on a collector that channels the water that enters the crepe towards a circular opening that configures the permeate outlet. The set is closed by a lid on the bottom.

As the filter retains solids in the granular medium, the pores through which water circulates are clogged. To allow the correct operation of the filter, periodically a backwash is carried out, consisting of circulating water in the opposite direction to the one described above, so as to drag the accumulated solids and restore the filter capacity of the filter. Despite the good performance offered by this type of filters in terms of elimination of suspended solids, they usually show a significant pressure drop, both in normal operation and in backwashing, that is, during the filter cleaning operation by circulating the fluid in opposite direction to the usual sense of the filtering operation. This is a relevant problem, since the water to be filtered is driven by a pump that must supply enough pressure to overcome the pressure drop that occurs in the filter. Thus, the energy consumption of the pump is directly affected by this pressure drop.

Summary of the invention

The invention aims to propose a granular matrix filter of the type indicated at the beginning, which without reducing its performance in terms of solids removal, has a lower pressure drop and, consequently, reduces the necessary pressure and electrical consumption of The filtering installation.

This purpose is achieved by a granular matrix filter of the type indicated at the beginning, characterized in that it also comprises a second, granular filter means, arranged in the chamber between the first filter medium and the first drain to be traversed by the fluid when circulating between the inlet and outlet, the second filter means having greater permeability than the first filter media, and a second drain, arranged to physically separate the first and second filter media, the second drain presenting a plurality of fluid passage holes of smaller dimensions to the granulometry of the first medium filter and because the first drain has a plurality of fluid passage holes of dimensions smaller than the granulometry of the second filter medium.

Thanks to the use of the second filter medium of greater granulometry, the first drain may have larger holes than the state of the art crepins. In turn, the second drain because it is not the last stage may have a larger passage surface. In addition, the second drain ensures that the first filter media will not descend and mix with the second filter media. These modifications result in a marked improvement in the pressure drop in the drainage zone with respect to the filter described in the prior art.

Furthermore, the invention encompasses a series of preferred features that are the subject of the dependent claims and whose usefulness will be highlighted later in the detailed description of an embodiment of the invention.

In a preferred embodiment, the first drain extends along the entire cross-section of the chamber and comprises a plurality of first windows of larger dimensions than the granulometry of the second filter medium, and which are covered with a first mesh having a plurality of fluid passage orifices of dimensions smaller than the granulometry of said second filter medium. Thanks to this, a robust drainage is obtained, but instead allows a significant increase in the cross section through which the fluid can be drained. This reduces the speed of passage through the drain, reducing the pressure drop, without worsening the filtration.

In another preferred embodiment, the second drain extends along the entire cross section of the chamber and comprises a plurality of second windows of larger dimensions than the granulometry of the first filter medium, and which are covered with a second mesh having the plurality of fluid passage holes of dimensions smaller than the granulometry of the first medium filter. This embodiment has associated the same advantages that appear in the first drain.

Preferably, said first drain and said second drain form an insertable drain device and adjusted to the contour of the walls of said chamber.

Especially preferably, said first and second meshes are stainless steel meshes.

Likewise, the invention also encompasses other detail features illustrated in the detailed description of an embodiment of the invention and in the accompanying figures. Brief description of the drawings

Other advantages and features of the invention can be seen from the following description, in which, without any limitation, preferred embodiments of the invention are mentioned, mentioning the accompanying drawings. The figures show:

Fig. 1, a front view, cut longitudinally along the plane l-l of Figure 2, of a granular matrix filter of the prior art.

Fig. 2, a top plan view of the state of the art filter of Figure 1. Fig. 3, a detail of the area A corresponding to the drainage of the state of the art filter of figure 1.

Fig. 4, a front view, longitudinally cut along the plane IV-IV of Figure 5, of a first embodiment of a granular matrix filter according to the invention.

Fig. 5, a top plan view of the filter of Figure 4.

Fig. 6, a detail of the zone B of figure 4. Fig. 7, a front view, longitudinally cut along the plane VII-VII of Figure 8, of a second embodiment of a granular matrix filter according to the invention.

Fig. 8, a top plan view of the filter of Figure 7.

Fig. 9, a detail of the area C of Figure 7.

Fig. 10A, a top perspective view of the filter drain of Figure 7.

Fig. 10B, a bottom perspective view of the filter drain of Figure 7.

Detailed description of embodiments of the invention

A first embodiment of the filter according to the invention is shown in Figures 4 to 6.

The granular matrix filter 1 comprises a tubular housing 24 of 200 mm diameter and 750 mm high that delimits an inner chamber 2. The housing 24 in this case has a cylindrical and vertical shape, but this should not be construed as limiting, since the cross section of the housing could vary in other shapes such as quadrangular, polygonal or others. On the upper part, the housing 24 incorporates a cylindrical conduit that forms a fluid inlet 4 that must be filtered, while a central opening is provided from the bottom of the chamber 2 that forms an outlet 6 of filtered or permeated fluid of 60 mm in diameter. Below the outlet 6 a manifold 26 is provided that empties into another tubular conduit. Although these are especially preferred arrangements for the inlet, the fluid outlet and the manifold 26, it is not ruled out that the position may be different and especially the inlet 4 and the conduit leaving the manifold 26.

As can be seen in Figures 4 and 6, the permeate outlet 6 is covered by a first drain 8 consisting of a parallelepipedic body having a plurality of first windows 16 that are coated with a stainless steel mesh 20 with a light inferior to the granulometry of the filter medium. However, this configuration could also replace a plurality of slots or holes. with lights lower than those of the filter medium. In addition, as seen in the figures, the windows are provided both on the upper horizontal face, and on the four lateral faces. The arrangement of windows on the side face makes it difficult for the first drain 8 to be easily clenched. In addition, it would also be conceivable that the filter 1 of this embodiment had several outlets 6, each of them being covered with a first drain 8.

Separated from this first drain 8 in the longitudinal direction of the housing 24, and above it, a second drain 10 is provided.

In the filter 1 according to the invention, on the second drain 10, a first granular first filter means 12 is arranged, arranged in the chamber 2 to be passed through the fluid when circulating from the inlet 4 in the direction of the outlet 6. Then, between the first and second drains 8, 10 the filter 1 comprises a second, granular second filter means 14. The second drain 10 is intended to physically separate the first and second filter means 12, 14.

Essentially in the invention, the second filter means 14 has a greater permeability than said first filter means 12, that is to say it has a more vast particle size and therefore opposes less resistance to the passage of the fluid.

For greater clarity of the figures, the first and second filter means 12, 14 have been represented only schematically by means of points of differentiated measurements and indicative of their differentiated particle sizes, but obviously chamber 2 contains an infinity of granules.

The substitution of the conical crepine of the state of the art, coated with a single filter medium, by a new parallelepiped crepine surrounded by a second filter medium 14 of granulometry greater than the first filter medium 12, the pressure drop can be significantly improved of filter 1 and in particular in the area of the crepe. In particular, the pressure drop can be measured by means of pressure gauges installed in the three ducts that protrude from the side wall of the housing 24. The person skilled in the art will understand that these three measurement ducts are not an essential part, nor necessary in the invention.

It has been observed that most of this pressure drop, approximately 60% takes place in the drain, the rest is distributed between the filter media column and the filter inlet and outlet pipes. In this way, the addition of a second filter means 14 combined with the physical separation of the first filter means 12 allows to reduce the speed of passage through the drain and reduce the areas of contraction of the flow.

The first filter medium 12 in this embodiment is siliceous sand with a particle size of 0.63 to 0.75 mm, since it has a good retention capacity of suspended solids. In turn, the second filter medium 14 used is ecofiltrant glass with a particle size of 0.85 to 1.50 mm. The following table 1 shows the physical characterization of the first and second means 12, 14.

Medium Parameter Units

First half 12 Second half 14

Siliceous sand Eco-filter glass

Granulometry 0.63-0.75 0.85-1, 50 mm

Bulk density 1 .478 1 .386 kg / m ³

Real density 2,573 2,420 kg / m ³

Porosity 42.2 42.7%

The following table shows the hydraulic characterization.

Medium Parameter Units

First half 12 Second half 14

Siliceous sand Eco-filter glass

Granulometry 0.63-0.75 0.85-1, 50 mm c ₂ 67,809 49,944 1 / m

1 / a 1 .426.866.416 794.666.385 1 / m ² Being C ₂ is the inertial factor (1 / m) and 1 / α is the viscous factor (1 / m ² ) characteristic of the filter medium.

The first and second drains 8, 10 are adapted to the corresponding granulometry of the first and second filter media 12, 14. Thus, the first drain 8 has a plurality of fluid passage holes of dimensions smaller than the particle size of the second filter media. 14 preventing the granules from escaping through the outlet 6. Also, the second drain 10 has a plurality of fluid passage holes smaller than the granulometry of the first filter medium 12. This again prevents the granules from crossing the second drain 10 and mix with the second filter medium 14. Thanks to avoiding this mixture, the permeate flow at outlet 6 is maximized.

As already indicated, the drains may simply be a mesh or a plurality of grooves sufficiently narrow to prevent the passage of the granules of filter media. However, particularly preferably, in order to obtain a robust configuration, the second drain 10 has a plurality of second windows 18 of larger dimensions than the granulometry of the first filter medium 12, and which are covered with a second mesh 22 which it has the plurality of fluid passage orifices of dimensions smaller than the granulometry of the first filter medium 12.

Finally, in case of sealing the first or second drains 8, 10, a backwash can be carried out, consisting of operating the filter in the opposite direction, so that the flow is directed from the outlet 6 to the inlet 4.

Below is another embodiment of the filter 1 according to the invention that share a large part of the characteristics described in the preceding paragraphs. Therefore, from now on only the differentiating elements will be described, while for the common elements reference is made to the description of the first embodiment. In this embodiment, the first drain 8 consists of a steel plate disc having a plurality of first windows 16 of larger dimensions than the granulometry of the second filter means 14. The first windows 16 are covered with a first mesh 20 which it has a plurality of fluid passage orifices of dimensions smaller than the granulometry of the second filter medium 14. It can also be seen that in this case, the disk extends along the entire cross section of said chamber 2, thanks to the which, the outlet 6 can have a much larger cross section. This again facilitates the flow and therefore further reduces the loss of charge at the outlet and therefore also reduces the energy consumption of the filter.

It is also worth mentioning that, in order to facilitate the maintenance of the filter according to the invention, the first drain 8 and the second drain 10 form an insertable drain device and adjusted to the walls of said chamber 2 as the one seen in Figures 10A and 10B.

The embodiments described so far represent non-limiting examples, so that the person skilled in the art will understand that beyond the examples shown, multiple combinations between the claimed characteristics are possible within the scope of the invention.

Claims

1 .- Filter (1) of granular matrix for filtering a fluid comprising

[a] an inner chamber (2) with an inlet (4) of said fluid to be filtered and a permeate outlet (6),

[b] a first drain (8) covering said permeate outlet (6), and

[c] a first granular filter means (12), arranged in said chamber (2) to be passed through said fluid when circulating between said inlet (4) and said outlet (6),

characterized in that it also includes

[d] a second, granular, second filter means (14) disposed in said chamber (2) between said first filter means (12) and said first drain (8) to be traversed by said fluid when circulating between said inlet (4) and said outlet (6), said second filter means (14) having greater permeability than said first filter means (12), and

[e] a second drain (10), arranged to physically separate said first and second filter means (12, 14), said second drain (10) having a plurality of fluid passage holes of dimensions smaller than the particle size of said first filter medium (12) and why

[f] said first drain (8) has a plurality of fluid passage holes smaller than the particle size of said second filter means (14).

2. Filter (1) according to claim 1, characterized in that said first drain (8) extends along the entire cross section of said chamber (2) and comprises a plurality of first windows (16) of larger dimensions that the granulometry of said second filter means (14), and that they are coated with a first mesh (20) having said plurality of fluid passage holes of dimensions smaller than the granulometry of said second filter means (14).

3. Filter (1) according to claim 1 or 2, characterized in that said second drain (10) extends along the entire cross section of said chamber (2) and comprises a plurality of second windows (18) of larger dimensions than the granulometry of said first filter means (12), and which are covered with a second mesh (22) having said plurality of fluid flow holes of dimensions smaller than the granulometry of said first filter medium (12).

4. Device according to any of claims 1 to 3, characterized in that said first drain (8) and said second drain (10) form an insertable drain device and adjusted to the contour of the walls of said chamber (2).