WO2022162517A1

WO2022162517A1 - Liquid filtration system

Info

Publication number: WO2022162517A1
Application number: PCT/IB2022/050586
Authority: WO
Inventors: Loren BELFORD
Original assignee: Netafim Ltd
Priority date: 2021-01-28
Filing date: 2022-01-24
Publication date: 2022-08-04

Abstract

A media filter having a central axis and comprising cylindrical inner and outer filtering members formed about the axis. The inner and outer filtering members define a peripheral spacing and the inner filtering member encloses a central spacing. The peripheral spacing is suitable for receiving media and the filter has a central piston member within the central spacing.

Description

LIQUID FILTRATION SYSTEM

TECHNICAL FIELD

[001] Embodiments of the invention relate to a liquid filtration system, in particular a media filtration system.

BACKGROUND

[002] Water filtration systems used in agricultural applications may include a metal or plastic tank with an inlet and an outlet and a bed of media (such as sand, peat, or the like) located in-between. Particles within the liquid may be physically removed by the media as the liquid flows therethrough.

[003] US4458059 for example describes a liquid filtration system that includes a tank, a liquid inlet tube and liquid outlet tube spaced apart. A porous filter is placed in the tank between the liquid inlet and liquid outlet that has a plurality of modules, each comprising a self-supporting body of granules cemented together and the upstream portion of the filter body contains a layer of fine aggregate while the downstream portion a layer of larger aggregate.

SUMMARY

[004] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

[005] In an embodiment there is provided a media filter having a central axis and comprising cylindrical inner and outer filtering members formed about the axis, the inner and outer filtering members defining therebetween a peripheral spacing and the inner filtering member enclosing a central spacing, the peripheral spacing being suitable for receiving media and the filter comprising a central piston member within the central spacing.

[006] The inner and outer filtering members may include apertures passing therethrough.

[007] The central piston member may be movable upwards and downwards with the central spacing during a backflushing operation of the filter.

[008] Possibly the filter includes a cylindrical piston at an upper axial side of the peripheral spacing. The cylindrical piston may be in various forms such as an inflatable member (or the like).

[009] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE FIGURES

[010] Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying figures, in which:

[Oi l] Fig. 1 schematically shows an embodiment of filtration setup that may be located at an upstream side of a water system, such as an irrigation water system;

[012] Figs. 2A and 2B schematically show various filter system embodiments that may be included in a filtration setup such as that seen in Fig. 1;

[013] Figs. 3A and 3B schematically show various stages of operation of the filter systems seen in Figs. 2A and 2B; and

[014] Fig. 4 schematically shows an enlargement of section IV marked in Fig. 2A. [015] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated within the figures to indicate like elements.

DETAILED DESCRIPTION

[016] Attention is first drawn to Fig. 1 schematically illustrating an embodiment of filtration setup 10 that may be located at an upstream side of a water system, such as an irrigation water system. The filtration setup is here optionally shown including three filtration systems 12 according to an embodiment of the present invention.

[017] The filtration setup has an incoming pipe 14, an outgoing pipe 16 and a flush pipe 18. Each filtration system 12 has an inlet 121 through which water to be filtered enters and an outlet 122 (see marked e.g., in Figs. 2) through which filtered water exits. A valve arrangement 20 (here in an optional form of a three-way valve) associated with each filtration system 12 - is connected to incoming pipe 14, to flush pipe 18 and to the inlet 121 of its associated filtration system.

[018] During a filtering operation, water entering the filtration setup via incoming pipe 14 can be controlled to branch off through each given valve arrangement towards the filtration system associated therewith. After being filtered, water can exit each filtration system through outgoing pipe 16 towards the water system being served.

[019] Backflushing a given filtration system may be accomplished by controlling the valve arrangement 20 associated with the given filtration system to open a pathway between the filtration system's inlet 121 and flush pipe 18. Water within outgoing pipe 16 that can be pressurized due to filtration operations of other filtration systems within the setup that feed filtered water into outgoing pipe 16, can then enter the given filtration system being backflushed via its outlet 122 and flow out of the given filtration system through its inlet 121 towards flush pipe 18. [020] An incoming command line 231 arriving at each valve arrangement can be arranged to control the operation of the valve arrangement. Further possible command lines 232, 233 may be used for controlling operations of various filtration system embodiments described herein. In a non-binding example, filtration systems of the various embodiments herein may be suited to filter water at flow rates of about 50 cubic meter per second (and the like); and perform backflushing operations at flow rates of about 30 to 50 cubic meter per second (and the like).

[021] Attention is drawn to Fig. 2A illustrating a possible embodiment of a filtration system 12. The view at the left-hand side of the figure shows the filtration system with filter media 30 and the view at the right-hand side of the figure shows the filtration system without the filter media. In a non-binding example, filer media possibly used in the various filtration system embodiments of the invention may include Silica Sand (and the like).

[022] Filtration system 12 has a central axis X and a cylindrical housing 32 that houses therein inner 34 and outer 36 cylindrical filtering members. The cylindrical housing 32 and the inner 34 and outer 36 filtering members are all formed about central axis X. Filtration system 12 can be seen including also a central piston member 38 in this example located at a lower end of a shaft 40 and a casing 42 that encloses a space within which shaft 40 can be located,

[023] The views provided in Fig. 2A show piston member 38 and its shaft 40 at a substantially upper most state where an upper end of the shaft is located at a substantially upper most side of the space defined by casing 42. Filtration system 12 can be arranged to include an incoming command port 44 at an upper side of casing 42, and a command line 232 (seen in Fig. 1) may be connected to command port 44.

[024] During a filtration operation, water entering the filtration system via inlet 121 flows and substantially fills a peripheral volume 31 formed in between housing 32 and outer filtering member 36. The water entering the filtration system also flows along substantial radial routes past apertures in outer filtering member 36 and through the filter media 30 to finally penetrate past apertures in the inner filtering member 34 as filtered water into a central outlet space 33 defined by the inner filtering member 34. From outlet space 33 the filtered water can flow out of the filtration system through its outlet 122 into outgoing pipe 16.

[025] Attention is drawn to the filtration system embodiment seen in Fig. 2B that substantially differs from the former embodiment in the inclusion of a peripheral piston member 46 that is located at an upper side of the spacing formed in-between the inner 34 and outer 36 cylindrical filtering members. As seen at the left-hand side of the figure, peripheral piston member 46 can be positioned to press against an upper side of the filter media 30 in order to keep it in place during a filtration operation of filtration system 12.

[026] Attention is drawn to Fig. 3A illustrating a backflushing operation of the filtration system embodiment seen in Fig. 2A. The left-hand side view in this figure represents a possible starting point of a backflushing operation, where the central piston member 38 is located at a substantial upper most position in the filtration system. Water entering the filtration system at its outlet 122 accordingly flows and substantially fills outlet space 33. Such water then flows along substantial radial paths through filter media 30 towards peripheral volume 31 and then out of the filtration system through its inlet 121.

[027] In certain cases, due to gravitational forces acting upon the filter media and/or due to larger compactness being present within particles at lower regions of the filter media - water paths passing through the filter media during backflushing may tend to form to a larger extent towards upper regions of the filter media 30. This may result in turbulence and hence cleaning actions between particles of the filter media being formed to larger extent towards upper regions of the filter media. Such water paths are represented by the generally radially outward arrows indicated in the left-hand view of Fig. 3A, which thicken towards upper regions of the filter media.

[028] In an aspect of the present invention, during backflushing the central piston member 38 may be activated to gradually move downwards within outlet space 33 and by that direct and force such water paths to flow through lower regions of the filter media. Such downward movement of the piston member 38 may be activated by hydraulic pressure being communicated via command line 232 towards command port 44.

[029] In certain embodiments, a valve arrangement being controlled to start backflushing via a command arriving via its incoming command line 231 - may be designed to simultaneously transfer hydraulic pressure for the piston movement via command line 232. After reaching a lower region of outlet space 33, the piston member 38 may be activated to retreat upwards, possibly by exposing command port 44 to atmospheric pressure at the ambient environment.

[030] Attention is drawn to Fig. 3B illustrating a backflushing operation of the filtration system embodiment seen in Fig. 2B. This backflushing operation is generally similar to that discussed with respect to the embodiment seen in Fig. 3A, however here generally differs by the provision of the peripheral piston member 46. During a filtration procedure, the piston member 46 as seen in the left-hand side of the figure - can abut and possibly slightly press against an upper side of the filter media in order to keep it in place. This may be the position of the peripheral piston member 46 also at the start of a backflushing operation.

[031] As the backflushing operation proceeds, the piston member 46 may be activated to retreat upwards as seen in the middle and right-hand side views of this figure. Such retreatment may be activated via command line 233. Piston member 46 may be embodied in various forms, such as an inflatable element (or the like). The retreated position of piston member 46 may assist in allowing particles within the filter media to decompress and allow water flows to pass therethrough during backflushing.

[032] Attention is drawn to Fig. 4 showing an enlargement of section IV marked in the right-hand side view of Fig. 2A. In certain embodiments, apertures may be absent or concealed in upper regions of the inner 34 and outer 36 cylindrical filtering members as indicated by the 'hatched' lines. This may be formed in order to avoid a so-called "short-circuit" of water flow that may be formed during filtering or backflushing that may bypass the region where filter media is present. [033] Such regions absent of apertures may be generally above an axial level of the central piston member 38. In certain embodiments, apertures may be absent to a lower axial level in the inner filtering member 34. This may be formed in order to ensure that water flow adjacent the inner filtering member 34, where flow rate is typically higher, does not "dig" into the filter media and by that bypass passing through the filter media.

[034] In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb.

[035] Further more, while the present application or technology has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and non- restrictive; the technology is thus not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed technology, from a study of the drawings, the technology, and the appended claims.

[036] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures can not be used to advantage.

[037] The present technology is also understood to encompass the exact terms, features, numerical values or ranges etc., if in here such terms, features, numerical values or ranges etc. are referred to in connection with terms such as “about, ca., substantially, generally, at least” etc. In other words, “about 3” shall also comprise “3” or “substantially perpendicular” shall also comprise “perpendicular”. Any reference signs in the claims should not be considered as limiting the scope. [038] Although the present embodiments have been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.

Claims

9 CLAIMS:

1. A media filter having a central axis and comprising cylindrical inner and outer filtering members formed about the axis, the inner and outer filtering members defining therebetween a peripheral spacing and the inner filtering member enclosing a central spacing, the peripheral spacing being suitable for receiving media and the filter comprising a central piston member within the central spacing.

2. The media filter of claim 1 and comprising a cylindrical piston at an upper axial side of the peripheral spacing.

3. The media filter of claim 1 or 2 and comprising a cylindrical housing formed about the outer filtering member.

4. The media filter of any one of the preceding claims, wherein filtering is of water flowing radially inwards past the outer and then inner filtering members towards the central spacing.

5. The media filter of any one of the preceding claims, wherein backflushing is of water flowing radially outwards past the inner and then outer filtering members.

6. The media filter of any one of the preceding claims, wherein the piston member being arranged to move within the central spacing.

7. A method of filtering comprising the steps of: providing a filter having a central axis and comprising cylindrical inner and outer filtering members formed about the axis, the inner and outer filtering members defining a peripheral spacing therebetween and the filter comprising a central spacing enclosed by the inner filtering member and a central piston member that is located within the central spacing, placing media within the peripheral spacing, and filtering water passing radially inwards past the outer and then inner filtering members towards the central spacing.

8. The method of claim 7, wherein backflushing the filter is by directing water to flow radially outwards past the inner and then outer filtering members.

9. The method of claim 8, wherein during backflushing the central piston is arranged to axially move through the central spacing.

10. The method of claim 9, wherein the central piston substantially blocks water from flowing axially upwards above it within the central spacing.

11. The method of any one of claims 7 to 10 and comprising a peripheral piston member located within the peripheral spacing.

12. The method of claim 11, wherein the peripheral piston member being arranged to substantially abut and/or press against the media during a filtering operation of the filter.

13. The method of claim 11 or 12, wherein the peripheral being arranged to retreat away from the media during a backflushing operation of the filter.

14. A filtering setup comprising an incoming pipe, an outgoing pipe, a flush pipe and a plurality of filters according to any one of claims 1 to 6, wherein a filtering operation of the filtering setup comprises directing water to flow from the incoming pipe through at least some of the filters towards the outgoing pipe.

15. The filtering setup of claim 14, wherein a backflushing operation of the filtering setup comprises directing water to flow from the outlet pipe through at least some of the filters towards the flush pipe while the other filters of the filtering setup perform a filtering operation.