Screen filter back flushing

Abstract

A screen filter has an inlet, an outlet, a flush opening, a central hub and a drive screw coupled to the central hub. The filter includes a filtering mode and a backflushing mode, while in the filtering mode the filter receives liquid via its inlet and directs the incoming liquid to pass through the filter's screen and then flow out of the filter via its outlet. In the backflushing mode the filter receives liquid via its inlet and directs at least a portion of the incoming liquid to be flushed out of the filter via its flush opening. The filter also includes an internal seal that moves either with the hub or the drive screw, and the internal seal moves with the hub and drive screw in the backflushing mode of the filter and by that opens a passage for the at least portion of the incoming liquid to be flushed out of the filter.

Description

[0001] SCREEN FILTER BACK FLUSHING

[0002] TECHNICAL FIELD

[0003]

[0001] Embodiments of the invention relate to filter arrangements, in particular of a type comprising screen filter(s) and cleaning mechanism for such screen filter(s).

[0004] BACKGROUND

[0005]

[0002] Common screen filter formations include a filter body, a cylindrical screen element and inlet and outlet ports. Non-filtered water enters through the inlet port at an incoming pressure P. From there the incoming water flows into an inner side of the cylindrical screen element, passing through the screen mesh where most dirt within the water is blocked and kept on the inner side of the cylindrical screen element as so called "filtration cake". Cleaner water then flows onwards towards the outlet port at pressure P out.

[0006]

[0003] Filters that include suction based hydraulic self-cleaning mechanisms, typically include a cleaning mechanism that facilitates cleaning of the screen's inner face by utilizing pressure differences between pressure within the filter and atmospheric pressure or other low-pressure source. Such filters typically have a central cleaning mechanism that includes an inner tube, positioned at the center of cylindrical screen element, with suction nozzles. The nozzle spouts are positioned in proximity to the screen's inner face in order to assist in cleaning the "filtration cake" by suction.

[0004] Some screen filters include other means such as brushes (or the like) for cleaning the "filtration cake" in the inner side of the screen of the filter. By utilizing pressure differences between pressure within the filter and atmospheric pressure such filters can be activated to flush this dirt out of the filter.

[0007]

[0005] Such a backflushing action for flushing dirt out of a screen filter is typically accomplished by urging water from within the filter to be flushed via a flushing chamber to the ambient environment. The flushing chamber may be connected or disconnected to the ambient environment by opening or closing an internal or external flush valve of the filter.

[0008]

[0006] As long as the flush valve is closed, the cleaning process is inactive and thus no filter cleaning occurs. Once the flush valve opens, pressure difference between pressure within the filter and the ambient environment or other lower pressure source urges the cleaning action to start.

[0009] SUMMARY

[0010]

[0007] The present disclosure relates to a fluid filtration system equipped with a self-cleaning mechanism. The system includes an inlet port, an outlet port, a purge outlet, a central assembly, and a rotary actuator connected to the central assembly. The filtration system operates in two distinct modes:

[0011]

[0008] Filtration Mode - In this mode, the system receives a liquid through the entry port, directing it through a permeable barrier (such as a mesh or sieve), allowing filtered fluid to exit via the discharge port while preventing impurities from passing through.

[0012]

[0009] Backflushing Mode - In this cleaning mode, the system channels a portion of the incoming liquid towards the purge outlet, effectively expelling contaminants from the filter. This is achieved through the movement of an internal sealing component, which is linked or mechanically associated with either the central assembly or the rotary actuator. The movement of this seal element in the backflushing mode creates a passage, enabling the flushing process.

[0010] The system may also incorporate cleaning elements affixed to the central assembly for additional debris removal. These elements can be in the form of: Brush components for scrubbing contaminants off the filter screen, or Vacuum nozzles that generate suction to extract accumulated particles.

[0013] [Oi l] In filtration mode, the seal component is positioned within the fluid passageway, exerting radial pressure against its inner surfaces to block unwanted flow towards the purge outlet. Alternatively, it may apply axial pressure against a seating surface to achieve the same sealing effect. In certain configurations, the seal element is designed to rotate independently from the central assembly or the rotary actuator to enhance durability and functionality.

[0014]

[0012] A corresponding operational method is also disclosed, detailing the steps for utilizing the system in both filtering and cleaning states, ensuring efficient filtration performance with automated or semi-automated maintenance.

[0015] BRIEF DESCRIPTION OF THE FIGURES

[0016]

[0013] 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:

[0017]

[0014] Fig. 1 schematically shows a known typical screen filter during filtering and backflushing operations;

[0018]

[0015] Figs. 2 to 9 and 12A, 12B schematically show various embodiments of screen filters of the present invention during filtering and backflushing operations;

[0019]

[0016] Fig. 10 schematically shows a close view of a manual handle of a filter for actuating a cleaning cycle of the filter's screen; and

[0020]

[0017] Figs. HA to 11C schematically show stages of modifying a manually operated cleaning mechanism of a screen filter to an automated operation.

[0018] 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.

[0021] DETAILED DESCRIPTION

[0022]

[0019] Attention is drawn to Fig. 1 schematically showing a known typical screen filter 10 during filtering (see left hand-side of figure) and backflushing (see right hand- side of figure) operations.

[0023]

[0020] The filter has an inlet 12 through which incoming liquid (e.g. water) to be cleaned is received, an outlet 14 through which the relative cleaner liquid can exit after filtering out dirt / particles, and a flush opening 16 through which liquid during a back-flushing cleaning action of the filter can be flushed out of the filter, possibly to the ambient environment.

[0024]

[0021] As seen, the filter has a flush valve 18 for controlling opening and closing of the passage for liquid to be flushed out of the filter via the flush opening 16.

[0025]

[0022] The flush valve 18 may be manually or automatically operated to open and close the passage, and a backflushing operation typically includes applying a cleaning action (e.g. by suction nozzles, brushes, etc.) to the inner side of the screen of the filter, while simultaneously opening the passage via the flush valve 18 for liquid to be flushed out of the filter.

[0026]

[0023] Attention is drawn to Fig. 2 schematically showing an embodiment of a screen filter of the present invention during filtering and backflushing operations.

[0027]

[0024] It is noted that this disclosure discusses two types of "seals": a first type referred to as a "face seal" and a second type referred to as a "radial seal" . In the context of this disclosure, a "face seal" is a seal that is pressed against a mating surface to form a barrier, preventing liquid from flowing towards an opening in the surface. A "radial seal," when inserted into a liquid passage, presses against the passage walls at its periphery to block liquid flow through the passage.

[0028]

[0025] The filter as seen includes a seal 18 in this example of a "face seal" type, which is coupled to a central hub 20 of the filter that is used for supporting cleaning members for cleaning the inner side of the filter's screen.

[0029]

[0026] It is noted that in the figures of this disclosure, when the cleaning members are not shown, numeral 17 will be used to indicate the region along the hub where such cleaning members are intended to connect.

[0030]

[0027] The central hub 20 is typically activated to move along a central axis X of the filter about which the filter's screen is formed.

[0031]

[0028] Such movement is accompanied also by rotation of the hub about said axis X so that the cleaning members, such as brushes (or the like) - which are coupled to the hub can perform a cleaning action to the inner side of the filter's screen.

[0032]

[0029] A drive screw 21 that is coupled in this example to a lower end of the hub may assist in creating this combined movement of the hub during the cleaning cycle of the filter.

[0033]

[0030] In the left-hand side figure, the seal 18 can be seen sealing an axial side of the filter so that liquid cannot flow outwards towards a flush opening 16 of the filter to be released to the ambient environment. Such sealing is accomplished in this example by axially pressing the seal 18 against a mating inner face 23 at this axial end of the filter, which is formed around an exit passage 25 from the filter's interior that leads towards the flush opening 16. As a result, liquid flow towards exit passage 25 is prevented.

[0034]

[0031] In the right-hand side figure, the seal 18 can be seen lifted axially away from face engagement with the filter's mating inner face 23 to thus allow liquid to flow via the exit passage 25 towards the flush opening 16 of the filter to be released to the ambient environment.

[0035]

[0032] Movement of the seal 18 in this example was accordingly formed due to the axial movement of the hub during its cleaning cycle.

[0033] In the embodiment of Fig. 2, the sealing of the exit passage 25 occurs at the axial point of contact of the seal 18 with the filter's inner face 23 and the sealing is maintained as long as the seal remains pressed against the inner face 23.

[0036]

[0034] In filters where an electrical motor is used for activating movement of the hub, the motor may be used to keep the seal pressed against the inner face. In filters where movement of the hub may be manually operated, the same may apply.

[0037]

[0035] With attention drawn to Fig. 10 it is seen that in certain cases, a handle 40 facilitating manual operation of the cleaning cycle may be equipped with a locking mechanism 100 to lock it in place when the seal 18 reaches a position where it presses against inner face 23. In this example, the locking mechanism 100 includes a lever 101 that can be moved to mesh with teeth 102 that are formed about the handle's base.

[0038]

[0036] Attention is drawn to Fig. 3 schematically showing another embodiment of a screen filter of the present invention during filtering and backflushing operations.

[0039]

[0037] The screen filter in this figure is generally similar to the one in Fig. 2 and mainly differs from it in the maimer in which its seal 18 in this example of a "radial seal" type blocks the flow of liquid via exit passage 25.

[0040]

[0038] As seen in the left-hand side of this figure, the seal is arranged to abut against a peripheral inner face 27 of the exit passage 25. Designing the sealing in this location enables to ensure that sealing of the exit passage 25 can occur at various positions of the seal 18 along an axial section of the passage's periphery 27. Therefore, means that may assist in ensuring axial processing of the seal against a certain face in the filter (such as the one seen in Fig. 10) may not be necessary.

[0041]

[0039] Attention is drawn to Fig. 4 showing a filter generally similar to the one seen in Fig. 3 including a seal 18 a "radial seal" type, which reveals in this perspective cross section a drive screw bearing 26 that may be formed about the drive screw in order to maintain the drive screw and hub centralized as they axially move and rotate.

[0040] It is noted that throughout the figures of this disclosure, either handles (indicating manual operation of cleaning) or motors (indicating automated operation of cleaning) can be seen. These illustrations indicate that the various inventive aspects disclosed herein may be equally applicable to either manual or motorized activation of cleaning cycles.

[0042]

[0041] Since the drive screw bearing 26 in Fig. 4 is located within exit passage 27, in order avoid block liquid flow towards the flush opening 16 during a backflush action of the filter, the drive screw bearing 26 can be seen including openings 1 through which the liquid can be allowed to flow.

[0043]

[0042] It is noted that filters shown in Figs. 2 to 4 illustrate examples of filers where the cleaning members applied against the inner side of the filter's screen act to generally scrape dirt away from the screen. Therefore, the flow of liquid during a backflush action is performed around the hub.

[0044]

[0043] Attention is drawn to Fig. 5 illustrating an embodiment where the cleaning of the inner side of the filter's screen during backflushing is accomplished with the assistance of suction nozzles 28. Typically, in such filters the flow of liquid sucked in via the suction nozzles is towards the inner side of the hub that is hollow, and from there towards the axial end of the hub that is exposed to the substantial zero pressure that is present in the ambient environment.

[0045]

[0044] In Fig. 5 this liquid flow can be seen being indicated by the 'dotted' arrows present in the right-hand side of this figure. As seen, during backflushing the flushed liquid flows out of the hub via peripheral openings 29 that are formed at an outer axial side of the hub. It is noted that in this disclosure, axial inner and outer directions are respectively defined as towards or away from the filter's interior.

[0045] The seal 18 in this example of a "face seal" type, is located in this embodiment axially outward beyond the openings 29. Also it is seen that the seal 18 is arranged when the filter is not in a cleaning cycle to axially abut against a mating peripheral ledge 30 that is located axially inwards in relation to the flush opening 16, in this example within exit passage 25.

[0046] Attention is drawn to Fig. 6 showing an example of a filter with a seal 18 of a "face seal" type generally similar to the one seen in Fig. 2 - where sealing is accomplished by pressing the seal 18 against a mating inner face 23 that is formed around an exit passage 25 from the filter's interior, which leads towards the filter's flush opening 16.

[0046]

[0047] Once the seal 18 is lifted from inner face 23 (see right-hand side of figure) - the liquid indicated by the 'dotted' arrows flows around the seal towards the flush opening 16, which in this example opens axially outwards from the filter (and not laterally sideways as in the example of Fig. 2).

[0047]

[0048] Attention is drawn to Fig. 7 showing an example of a filter with a seal 18 of a "radial seal" type generally similar to the one seen in Fig. 3 - where sealing is accomplished by an outer periphery of seal 18 being arranged to seal against a peripheral inner face 27 of the exit passage 25.

[0048]

[0049] Once the seal 18 is moved axially inwards to a position that is inward to the exit passage 25, the liquid indicated by the 'dotted' arrows flows around the seal towards the flush opening 16, which in this example also opens axially outwards from the filter (and not laterally sideways as in the example of Fig. 3).

[0049]

[0050] Attention is drawn to Fig. 8 showing an example of a filter where cleaning of the inner side of the filter's screen during backflushing is accomplished with the assistance of suction nozzles. As a result (as also discussed with respect to Fig. 5) the liquid sucked in via the suction nozzles flows towards the inner side of the hub that is hollow, and from there towards the flush opening 16.

[0050]

[0051] The liquid flows as indicated by the 'dotted' arrows through passages formed within a base 77 that supports at its lower axial side a seal 18 of a "face seal" type, and when the seal 18 is lifted away from a mating peripheral ledge 300 - this liquid accordingly flows to the ambient environment. Here the ledge 300 is an inward facing surface and the seal 18 when sealing the exits towards the flush opening 16 presses outwards against the ledge. Moving the seal inwards lifts it from the ledge 300 to open a passage for flow towards the flush opening 16.

[0052] Attention is drawn to Figs. 12A and 12B showing yet another example of a filter where cleaning of the inner side of the filter's screen during backflushing is accomplished with the assistance of suction nozzles. As a result (as also discussed with respect to Figs. 5 and 8) the liquid sucked in via the suction nozzles flows towards the inner side of the hub that is hollow, and from there towards the flush opening 16 of the filter.

[0051]

[0053] In this example, a stub 958 fitted to an outer open axial end of the hub protrudes axially outward towards a flange 71 that carries a seal 18 of a "face seal" type on its inner side that faces inwards. As seen in Fig. 12B, when the hub moves outwards, its seal 18 lifts off from the flush opening 16 to allow liquid to be flushed and flow to the ambient environment. As seen in Fig. 12A, when the hub moves back inwards the seal 18 seals the flush opening 16 by pressing inwards against a peripheral rim 454 of the flush opening 16.

[0052]

[0054] In Fig. 9 the seal 18 of a "radial seal" type abuts with its outer periphery against an inner face of the passage below the aforementioned discussed ledge 300 that leads liquid during a backflushing operation of the filter towards the filter's flush opening 16. Urging the seal axially inwards to position it within a wider diameter section that is inwards to ledge 300 permits liquid to flow passed the seal 18 towards the filter's flush opening 16.

[0053]

[0055] Attention is drawn to Figs. 11A to 11C to describe an aspect of the present invention, which is related to modifying a manually operated screen filter to include a motor for activating in an automatic and controlled way back flushing of the filter.

[0054]

[0056] In Fig. 11 A, a handle that is used for manually operating the backflushing action of the filter is seen being removed, leaving an outer section 900 of the flier's drive screw 21, which is coupled to its hub - exposed to the exterior of the filter.

[0055]

[0057] As seen in the exploded view of Fig. 11B, a motor housing 901 is provided including a motor 902 at its outer axial side - and a link member 903 is provided for linking the drive screw's outer section 900 to the motor 902.

[0058] As seen in the assembled state of Fig. 11C, the link member 903 is fitted upon outer section 900 and a pin 904 is then placed through a bore formed at the tip of the outer section 900. The pin 904 is located at it's sides within opposing axially extending slits 9031 of the link member 903, while the link member is attached at its outer end to the motor 902.

[0056]

[0059] Powering the motor 902 to revolve will transfer the motor's rotating motion via the link member 903 to the drive screw's outer section 900. As a result, a cleaning action of the filter may be powered by the motor to scan and clean the filter's screen, while opening a passage for liquid to flow out of the filter via its flush opening 16 as the filter's seal 18 moves and allows liquid to be flushed out of the filter.

[0057]

[0060] In the present disclosure, seals of either the "face seal" or "radial seal" type may, in certain cases, be fixed in place within the various filter embodiments described herein. This fixation ensures that the seals move axially and rotationally together with the filter's supporting element, e.g. hub or an extension thereof such as the drive screw (or the like), as said supporting element axially moves and rotates. However, in some cases, relative rotational motion between the seal and the supporting element may be permitted. For instance, in the case of a seal of a "face seal" type, in order e.g. to minimize friction, the seal may be substantially free to rotate relative to the rotating supporting element as it biases the seal against its mating surface.

[0058]

[0061] 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.

[0059]

[0062] 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.

[0060]

[0063] 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.

[0061]

[0064] 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.

[0062]

[0065] 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

CLAIMS:

1. A screen filter comprising an inlet, an outlet, a flush opening, a central hub and a drive screw coupled to the central hub, the filter having a filtering mode and a backflushing mode, wherein in the filtering mode the filter being adapted to receive liquid via its inlet and direct the incoming liquid to pass through the filter's screen and then flow out of the filter via its outlet, while in the backflushing mode the filter being adapted to receive liquid via its inlet and direct at least a portion of the incoming liquid to be flushed out of the filter via its flush opening, wherein the filter comprises an internal seal being coupled or associated to move either with the hub or the drive screw, and said internal seal being adapted to move together with the hub and drive screw in the backflushing mode of the filter and by that open a passage for the at least portion of the incoming liquid to be flushed out of the filter.

2. The screen filter of claim 1 and comprising cleaning members fixed to the filter's central hub in order to clean the filter's screen.

3. The screen filter of claim 2, wherein the cleaning members are brushes.

4. The screen filter of claim 2, wherein the cleaning members are suction nozzles.

5. The screen filter of any one of the preceding claims, wherein in the filtering mode the seal is adapted to be located within a liquid passage of the filter and press at its periphery against the walls of the passage to prevent liquid from flowing towards the flush opening.

6. The screen filter of any one of claims 1 to 5, wherein in the filtering mode the seal is adapted to axially press against a mating surface of the filter in order to prevent liquid from flowing towards the flush opening.

7. The screen filter of claim 7, wherein the seal is free to rotate relative to the hub or the drive screw.

8. A method for operating a screen filter comprising the steps of: providing screen filter comprising an inlet, an outlet, a flush opening, a central hub and a drive screw coupled to the central hub, wherein in a filtering mode the filter being adapted to receive liquid via its inlet and direct the incoming liquid to pass through the filter's screen and then flow out of the filter via its outlet, while in the backflushing mode the filter being adapted to receive liquid via its inlet and direct at least a portion of the incoming liquid to be flushed out of the filter via its flush opening, wherein the filter comprises an internal seal being coupled or associated to move either with the hub or the drive screw, and said internal seal being adapted to move together with the hub and drive screw in the backflushing mode of the filter and by that open a passage for the at least portion of the incoming liquid to be flushed out of the filter.

9. The method of claim 8 and comprising cleaning members fixed to the filter's central hub in order to clean the filter's screen.

10. The method of claim 9, wherein the cleaning members are brushes.

11. The method of claim 9, wherein the cleaning members are suction nozzles.

12. The method of any one of claims 8 to 11, wherein in the filtering mode the seal is adapted to be located within a liquid passage of the filter and press at its periphery against the walls of the passage to prevent liquid from flowing towards the flush opening.

13. The method of any one of claims 8 to 11, wherein in the filtering mode the seal is adapted to axially press against a mating surface of the filter in order to prevent liquid from flowing towards the flush opening.

14. The method of claim 13, wherein the seal is free to rotate relative to the hub or the drive screw.

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