Abstract:
Provided is a filtration cassette having a rigid body configured for externally supporting a filtration media disposed thereover and having at least one filtering surface configured with a flow path facilitating filtered fluid flow from a space extending between the filtration media and the filtering surface, and extending towards an outlet terminal. Also provided is a filtration segment including such a filtration cassette and where the filtration media is a filtration thread tensionally coiled over the filtration cassette at a multi-layered and tight configuration. Further provided are a plurality of such filtration segments which are configured into a disk-type assembly forming a filtration unit for a filtering system.

Description:
FIELD OF THE PRESENT DISCLOSED SUBJECT MATTER 
       [0001]    The present disclosed subject matter relates to filtration units and filtration systems making use of same. The present disclosure is further concerned with a filtration method using filtration units and filtration systems of the specified type, and methods for rinsing the filtration units. 
       BACKGROUND OF THE PRESENT DISCLOSED SUBJECT MATTER 
       [0002]    Disk filters, at times referred to also as plate filters, are well known and are in use for many years. 
         [0003]    A disk filter system typically comprises a plurality of parallely disposed discs, each composed of a plurality of filtering segments (sectorial segments, trapezoidal segments, or otherwise shaped), coupled together to form a disk-shaped filtration element. 
         [0004]    Examples of disk filters are disclosed in Canadian Patent publication CA 2510282A disclosing a filter sector for a disc filter, said sector having a root and a tip with a plurality of radial supports extending there between, each of said supports having a channel section with opposed walls diverging said tip to said root, said radial supports being interconnected by lateral members to define a pair of oppositely directed faces to support a filter membrane. 
         [0005]    A further disk system is disclosed in WO 2006/084858 directed to a static plate filter with a continuous flow for the filtering of liquids comprising a set of static filtrating plates with a filtering fabric, a central fissured tube with a cavity section for the evacuation of the filtered liquid, a waterproof aspiration chamber, a rotating cleaning device for the regeneration of the plates, with a header which rotates around the aspiration chamber with which it is in direct contact, on which are coupled fissured tubes for the cleaning and aspiration of the filtering fabric, where the fissured tubes of the rotating cleaning device stick to the filtering fabric and their position in such that it guarantees the cleaning of the adjacent faces of two near plates. 
         [0006]    A particular filtering media is disclosed in an article entitled [Real World Performance and Low Cost Operation Maximizes Benefits of Disc-Type Filtration], by Siemens Water Technologies, available at: 
         [0007]    http://www.water.siemens.com/SiteCollectionDocuments/Product_Lines/Davis_Products/Brochures/BC-FORTYX3-BR-0809.pdf (last accessed on Sep. 29, 2011). 
       SUMMARY OF THE PRESENT DISCLOSED SUBJECT MATTER 
       [0008]    Filters in accordance with the disclosed subject matter can be used for filtering different fluid media, including gaseous material and different liquids such as fresh water, irrigation water, contaminated water including sewage, emulsions, sea water, viscous liquids, with the range of fluid pressure and other parameters thereof being substantially unlimited. 
         [0009]    The term fluid is thus defined hereinafter as any flowable matter, i.e. gas or liquid, regardless its purpose, degree of contamination, particle size, viscosity, pressure or any other parameters. Hence, herein in the specification and claims the term fluid is used in its broadest sense. 
         [0010]    It is an object of the present disclosed subject matter to provide a filtering segment and a filtration cassette therefore, for use in conjunction with a disk-type filtration system. 
         [0011]    It is another object of the present disclosed subject matter to provide a disk-type filtration system configured with filtration segments according to the present disclosed subject matter. 
         [0012]    It is yet an object of the present disclosed subject matter to provide a rinsing system for a disk-type filtration system. 
         [0013]    A filtration segment according to the disclosed subject matter comprises a filtration cassette configured as a rigid body externally supporting a filtration media disposed thereover and having at least one filtering surface configured with a flow path facilitating filtered fluid flow from a space extending between the filtration media and the filtering surface, and extending towards an outlet terminal. 
         [0014]    The filtration media, according to a particular design is a thread tensionally coiled (wrapped) over the filtration cassette unit at a multi-layered and tight configuration. The thread is substantially continuous. The tension of the coiled (wrapped) thread can vary about the longitudinal axis of the filtration cassette and/or between wrapping layers. The filtration media can be composed of a thread, continuous or not, with an altering thickness. 
         [0015]    According to an embodiment of the disclosed subject matter, the thread filter media is wrapped about a longitudinal axis of the filtration cassette. 
         [0016]    The filtration cassette, according to one particular configuration, is a flat, trapezoidal structure, such that an array of like filtration cassettes can be assembled into a near-to-circular, disc-like filtering assembly. 
         [0017]    The filtering surface is configured with a plurality of ribs projecting from the surface for supporting the filtration media and facilitating fluid flow through the flow path, over the surface and between the plurality of ribs. The flow path extends over the filtering surface of the filtration cassette and then extends into a collecting duct within the rigid body (through the filtering surface) and further towards the outlet terminal. 
         [0018]    The filtration cassette is configured for assembly in a radial setup to a filtered fluid collecting duct. Coupling to the collecting duct is facilitated through a coupler of the outlet terminal (which according to a particular design extends along the longitudinal axis of the filtration cassette), configured for articulation to the collecting duct and being in flow communication therewith, wherein assembly of such filtration cassettes in a juxtaposing configuration gives rise to the disc-like filtering system. 
         [0019]    The coupler can be tubular member configured for press-fit into a corresponding receptacle at the fluid collecting duct, in fluid tight fashion. 
         [0020]    The filtering surface can be flat or can be configured with a concaved cross-section. A centerline of the concavity extending substantially parallel to the longitudinal axis of the filtration cassette. 
         [0021]    The filtration cassette can be made of a plastic molded material with both filtration surfaces being substantially same. 
         [0022]    The filtration cassette is configured at a distal end thereof with an arresting portion for securing at an assembled position to thereby prevent spontaneous detaching from a collecting duct of a filtration system. The arresting portion can be in the form of a band-receiving groove configured at a rear end of the filtration cassette. 
         [0023]    According to yet an aspect of the disclosed subject matter there is provided a disk-like filtering unit configured with an array of filtration segments of the aforementioned type, said filtration segments being coupled into a filtered fluid collecting duct of the filtering system for providing filtered fluid. Further there is provided a rinsing mechanism for rinsing the filtration cassettes. 
         [0024]    Filtration segments of a filtering unit are secured to thereby prevent their spontaneous detaching from the collecting duct. Securing can be configured by a band radially packing the filtration segments, or by a coupler arrangement between neighboring filtration segments. 
         [0025]    According to a particular design, the filtering system comprises a plurality of parallely extending fluid jet emitting arms, with at least one jet emitting nozzle juxtaposing and facing a filtration media of a filtration cassettes of the disk-like filtering units, and configured for selectively emitting a jet of rinsing fluid over the filtration media. 
         [0026]    A rinsing mechanism according to the disclosed subject matter, for a disk-type filtration system, comprises at least one fluid jet emitting arm juxtaposed and facing a filtration media of a filtration cassette, and configured for selectively emitting a jet of rinsing fluid over the filtration media. According to one example the at least one jet emitting arm is fitted with an array of jet nozzles disposed along its length and facing the filtration media, and whereby disc-like filtering units are rotationally displaceable about a central axis thereof, whereby a rinsing fluid jet is applied substantially over the entire surface of the filtration media as they rotate with respect to the jet emitting arms. 
         [0027]    According to another configuration, the rinsing mechanism comprises one or more jet emitting arms, each fitted with one or more jet nozzles near a distal end of the one or more arms and wherein the arms are configured for reciprocal pivotal displacement (in a turntable-arm resembling fashion) over the filtration media of the disc-like filtering units, and whereby the disc-like filtering units are rotationally displaceable about a central axis thereof, whereby a rinsing fluid let emitted from the jet nozzles substantially rinses an entire face of a filtration segment. According to a particular design, the jet emitting arms are pivotally disposed near a periphery of the filtration cassettes. 
         [0028]    Rotation of the disc-like array of disc-like filtering units and/or manipulating motion of the one or jet emitting rinsing arms of the rinsing mechanism is facilitated by any type of motion generating mechanism, such as an electric motor, a hydraulic motor, pneumatic actuators, etc., and combinations thereof 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    In order to understand the present disclosed subject matter and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: 
           [0030]      FIG. 1A  is a planar view of a filtration segment in accordance with the first aspect of the present disclosed subject matter; 
           [0031]      FIG. 1B  is a front perspective view of a filtration cassette unit used in the filtration segment of  FIG. 1A ; 
           [0032]      FIG. 1C  is a rear perspective view of  FIG. 1B ; 
           [0033]      FIG. 1D  is a top planar view of  FIG. 1B ; 
           [0034]      FIG. 2A  is a section along line I-I in  FIG. 1C ; 
           [0035]      FIG. 2B  is a section along line II-II in  FIG. 1C ; 
           [0036]      FIG. 2C  is a longitudinal section along line in  FIG. 1C ; 
           [0037]      FIG. 3A  is a longitudinal section along line V-V in  FIG. 1A ; 
           [0038]      FIG. 3B  is an enlargement of the portion marked B in  FIG. 3A ; 
           [0039]      FIG. 3C  is a sectioned view at enlarged scale, of a portion taken along line IV-IV in  FIG. 1A ; 
           [0040]      FIG. 4  is a perspective view of a disk-like filtering unit composed of a plurality of filtration segments seen in  FIG. 1A ; 
           [0041]      FIG. 5A  is a front perspective view of a filtering system in accordance with a configuration of the present disclosed subject matter; 
           [0042]      FIG. 5B  is a rear perspective view of  FIG. 5A ; 
           [0043]      FIG. 6A  illustrates the filtering tem of  FIGS. 5A and 5B  with several components removed for clarification; 
           [0044]      FIG. 6B  illustrates the filtering unit of  FIGS. 5A and 5B  with disk-like filtering units removed for clarification; 
           [0045]      FIG. 6C  is an exploded view of the filtering system of  FIGS. 5A and 5B ; 
           [0046]      FIG. 7  is a rinsing mechanism in accordance with an example of the present disclosed subject matter, suitable for use with a filtering system of the disclosed subject matter; 
           [0047]      FIGS. 8A to 8F  illustrate different views and close-ups of a filtration assembly accommodating a filtering system in accordance with an example of the disclosed subject matter, wherein: 
           [0048]      FIG. 8A  is a perspective, partially cutout view of the filtration assembly; 
           [0049]      FIG. 8B  is an enlargement of the portion marked B in  FIG. 8A ; 
           [0050]      FIG. 8C  is a schematic end view of the filtration assembly; 
           [0051]      FIG. 8D  an enlargement of the portion marked D in  FIG. 8C ; 
           [0052]      FIG. 8E  is a view of the filtration assembly illustrating fluid flow scheme; 
           [0053]      FIG. 8F  is an exploded view of the filtration unit and rinsing mechanism; 
           [0054]      FIG. 9  is a perspective view of a rinsing mechanism in accordance with a different example, for use in conjunction with a filtering system in accordance with the disclosed subject matter; 
           [0055]      FIG. 10A  is a perspective view of a rinsing mechanism in accordance with the example of  FIG. 9 , with its left support mechanism removed for clarification; 
           [0056]      FIG. 10B  is a bottom perspective view of  FIG. 10A ; 
           [0057]      FIG. 10C  is a section along line X-X in  FIG. 10A ; and 
           [0058]      FIG. 10D  is a perspective view of the rinsing mechanism of  FIG. 10A , sectioned along inclined line XI-XI in  FIG. 10A . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0059]    In  FIG. 1A  of the drawings there is illustrated a filtration segment generally designated  20 , in accordance with a first aspect of the present disclosed subject matter, useful as a filtering component in a filtering unit in accordance with further aspects of the present disclosed subject matter, and as will be discussed hereinafter in further detail. 
         [0060]    The filtration segment  20  comprises a filtration cassette  30  seen in further detail in  FIGS. 1B to 1D ,  2 A to  2 C and  3 A to  3 C. The filtration cassette  30  is a substantially flat, trapezoidal structure which in the present example is a plastic molded article and is thus durable and light weight. The filtration cassette  30  comprises a top filtering surface  32  and a bottom filtering surface  34  extending between a narrow, front base  36  and a wider, rear (distal) base  38 , and defining together a trapezoidal shape extending about a longitudinal axis X. The structure of the filtration cassette  30  is reinforced by laterally exuding end portions  37  (at the front end) and  39  (at the rear end), rendering the structure twist resistance and bending resistance, and further serving to pack the thread filtering media, as illustrated in  FIG. 1A . 
         [0061]    Each of the top filtering surface  32  and bottom filtering surface  34  is substantially flat and comprises a plurality of longitudinal ribs  42  obliquely oriented with respect to the longitudinal axis X and projecting from the respective filtering surface  32  and  34  and defining together a flow path (designated by arrowed lines  90 ) directing fluid flow towards apertures  48  formed near the front end  36  of the support unit  30 . The apertures  48  are through-going over the top and bottom filtering surfaces  32  and  34  and defining together a flow path extending between the ribs  42 , into the openings  48  and into a collecting duct  52  (best seen in  FIG. 2C ). The collecting duct  52  extends coaxial with the longitudinal axis X, from which the flow path extends into a coupler  58  coaxially projecting from the front base  36  and configured for coupling to a central collecting line (constituting part of the filtering assembly; in the form of a filtered fluid collecting duct, namely a cylindrical pipe  108  in  FIG. 6A ). Some of the longitudinal ribs  42  are interrupted along their length to facilitate fluid flow therebetween. Coupler  58  is typically configured with a groove receiving a sealing O-ring (not shown). 
         [0062]    It is further noted that the longitudinal left and right edges  62  of the filtration cassette unit  30  are rounded and further, that the front base  36  and the rear base  38  project beyond said side edges  62  and above the filtering surfaces  32  and  34  as well as above the respective longitudinal ribs  42 . This arrangement guaranties that a wrapped (coiled) pack of filtration thread  55  ( FIGS. 1A ,  3 A and  3 B) substantially does not project beyond a top-most surface  64 A of the rear base  38  or a top-most surface  64 B of the front base  36 , or beyond a bottom-most surface of the rear base  38  or of a bottom-most surface of the front base  36 , respectively, nor beyond a lateral male projection  68 A (at the rear base  38 ) or  68 B at the front base  36 , or of a lateral female projection  70 A at the rear base  38  or  70 B at the front base  36 , the purpose of said lateral projections to become apparent hereinafter. 
         [0063]    Thus, it is appreciated, and as can be seen in  FIGS. 1A and 3A  and  3 B, that the filtration media in the form of a pack of wrapped filtration thread  55 , does not exceed any of said boundaries whereby it is protected and thus prevented from damage. 
         [0064]    It is further noted that the lateral male projections  68 A and  68 B are configured for receiving and engagement by corresponding female lateral projections  70 A and  70 B respectively, as can be seen in the disk-like filtering unit generally designated  80  in  FIG. 4 , composed of a plurality of planar disposed like filtration cassettes  30 . The disk-like filtering unit  80  is maintained in its tight planar configuration of  FIG. 4  by means of an arresting portion in the form of a band  82  received within a band-receiving groove  84  formed at the rear base  38  of each filtration cassette  30  (said groove  84  may in fact extend between a pair projections  86  at the rear base) the band  82  may be an elastic band or a band of other nature secured in place by a latch  88 . 
         [0065]    As illustrated in the drawings, the flow path extends under the filtration media  9 i.e. the wrapped filtration thread  55 ) between the filtering surfaces  32  and  34  along the arrowed lines designated  90 . Thus, it is apparent that the flow path extends between the filtering surfaces  32  and  34  and the bottommost layer of the wrapped thread  55 , however between the ribs  44  which are configured so as to facilitate fluid flow and direct it towards the apertures  48  (and for that purposes some of the ribs  42  are interrupted at several locations indicated  43 ). 
         [0066]    Whilst in the illustrated example hereinabove the top filtering surface  32  and bottom filtering surface  34  are substantially parallel to one another, other forms are configurable. For example, one or both of the top filtering surface and bottom filtering surface can be concave or convex (not shown). Furthermore, the filtration cassette may have other than trapezoidal shape, e.g. rectangle and the like. 
         [0067]    With further attention being now made to  FIGS. 5 and 6  of the drawings there is illustrated a filtering system generally designated  100 , comprising an array of parallely disposed disk-like filtering units  80  (of the type disclosed hereinafter and discussed in connection with reference to  FIG. 4 ) and used within a filtration assembly, e.g. filtering assembly  204  in  FIG. 8 . 
         [0068]    Filtering system  100  comprises a pack of several disk-like filtering units  80 , wherein the disk-like filtering units  80  extend parallel to one another along a common central axis Y, and are secured over a central filtering fluid collecting duct (pipe)  108  which as can be seen in  FIG. 6A  is formed with a plurality of receptacle openings  112  into which the coupler  58  ( FIG. 1A ) of each of the filtering cassettes  30  fits, typically by press fit, in a fluid-sealed fashion (an O-ring is fitted over the coupler) and are further secured and prevented from disengaging or displacement by means of the band  82 , as discussed in connection with  FIG. 4 . Thus, each filtration cassette  30  is in flow communication with the inside space  116  of the filtered fluid collecting duct  108  through the respective coupler  58 , wherein filtered fluid flows into said space  116  and as will be discussed hereinafter in connection with  FIG. 8  is then collected and transferred for use. 
         [0069]    The filtering system  100  further comprises a pair of disc-like end plates  120  securely mounted over the central fluid collecting pipe  108  and are pressingly secured by a pair of locking fasteners  122  securely coupled over the collecting pipe  108 . 
         [0070]    The end plates  120  further support a rinsing mechanism generally designated  138  (removed from its seat  139  in  FIG. 6A ; said rinsing mechanism  138  being one of two examples as will be discussed hereinafter in further detail). It is also noted that the rinsing mechanism  138  is configured with a rinsing fluid inlet port  140 . 
         [0071]    The filtering system  100  can be a single item within a filtration assembly, or it can be part of an array of like filtering units wherein such filtering units coaxially coextend (along the Y axis) with fluid flow extending between the respective filtered fluid collecting ducts  108  and also between neighboring rinsing mechanisms  138  through pipe segments  140  extending into a respective coupling end  142  at an opposed end thereof ( FIG. 5A ). For coupling to neighboring coaxial filtering units, the fluid collecting ducts  108  may project beyond one or both of the end supports  120 , or an extension pipe segment  127  may be coupled thereto via fasteners  122  (see  FIG. 6C ). however, a plurality of filtration system can be configured also in parallel relation, with suitable collecting pipes extending therebetween (not shown). 
         [0072]    Owing to the nature of the filtering system  100 , namely its assembly of a plurality of adjoining disk-like filtering units  80 , there is the need to provide a cleaning mechanism competent for rinsing the filtering media, namely the coiled threads in between the disk constructions. For that purpose, a rinsing mechanism is provided, as illustrated in  FIGS. 5 and 6 . A first example of a rinsing mechanism will be discussed hereinafter with reference to  FIGS. 7 and 8  of the drawings and generally designated  200 . 
         [0073]    Rinsing mechanism  200  comprises a solid support block  202  secured to the housing  208  of the filtering system  204  (or to the end plates  120 ) and comprises a rinsing fluid inlet port  210  extending from the housing  208  and into a rinsing fluid distribution line  212 , from which radially extend a plurality of jet emitting arms  216  and  218  (their configuration best seen in  FIG. 7 ), arranged in two offset rows such that the arms  216  of one row alternate the arms  218  of the other row, wherein the arms are so mounted that their free ends extend towards the filtered fluid central collecting pipe  108  of the filtering system, at a substantial radial orientation. Each of the jet emitting arms  216  and  218  is configured with a plurality of jet emitting nozzles  220  facing the filtration cassettes  20  of the disk-like filtering assemblies  80  (i.e. configured for emitting rinsing fluid in the axial direction). The distribution of the jet emitting nozzles  220  is configured for covering substantially the entire surface of the filtering media. 
         [0074]    In the particular example the rinsing mechanism  200  is a static mechanism wherein the disk-like filtering units  80 , mounted over the central collecting pipe  108  are rotatable (arrow  235  in  FIG. 8C ) by motor  255 , whereby rotating the filtering unit  100  whilst applying a rinsing fluid through the jet emitting arms  216  and  218  results in rinsing/cleaning of the filtering cassettes  30 . 
         [0075]    Notable, rotation of the disc-like array of disc-like filtering units is facilitated by any type of motion generating mechanism, such as an electric motor, a hydraulic motor, pneumatic actuators, etc., and combinations thereof. 
         [0076]    In the illustration of  FIG. 7  the housing  202  comprises a single rinsing fluid distribution line  212  whilst in the illustrations of  FIGS. 8A to 8F  there are provided two fluid distribution lines  212 A and  212 B, each associated with a row of arms  216  and  218  respectively, however both are in fluid communication with the rinsing fluid&#39;s inlet port  210 . 
         [0077]    The rinsing mechanism  200  of  FIG. 7  is further configured with a controlled rinsing fluid distribution system  217  with a plurality of flow control gates  219 , each being in flow communication with the rinsing fluid distribution line  212  and with a respective rinsing arm  216  and  218 , whereby a hydraulic/pneumatic/electric or combined controller opens/closes the control gates  219  to facilitate rinsing fluid to the respective rinsing arm. 
         [0078]    With reference to  FIG. 8E  there is illustrated the filtration assembly  204  configured with a raw fluid inlet port  240  connectable to a supply of raw fluid (not shown) and extending into the inner filter space  242 . The plurality of disk-like filtering units  80  are fitted over the fluid collecting pipe  108  in a fluid tight manner, wherein said pipe  108  extends into a filtered fluid collecting chamber  244  configured with a filtered fluid outlet port  246  connected to a consumption pipe (not shown). The housing  208  of the filtration assembly  204  is further fitted with a rinsing fluid inlet port  210 , which as explained hereinabove, is in flow communication with the rinsing fluid distributor line  212 , which in turn is in flow communication with the plurality of jet emitting arms  216  and  218  alternatingly distributed between neighboring disk-like filtering assemblies  80 . The central space  242  of the filtering system  204  is further configured with a rinsing/flushing fluid outlet port  250 . 
         [0079]    The arrangement is such that during a filtering process the rinsing fluid inlet port  210  and the flushing outlet port  250  are shut whilst raw fluid enters the filtration assembly through inlet port  240 , flows through the plurality of filtration segment  20  of the disk-like filtering units  80 , into the space  116  of the collecting tube  108  and then into chamber  244  from which the filtered fluid flows out for consumption through outlet port  246 . 
         [0080]    When it is now required to rinse the filtration assembly  204 , the inlet port  240  and the filtered fluid outlet port  246  are shut whilst a rinsing fluid is pressurized through the rinsing fluid inlet port  210 , resulting in rinsing fluid jets emitting through the nozzles  220  (configured on arms  216  and  218 ) directed towards the coiled filtering threads and simultaneously, the electric motor  255  is operated, giving rise to rotation of the filtering unit (namely the collecting pipe  108  with the associated disk-like filtering assemblies  80 ). It is however appreciated that rather than electric motor  255  hydraulic or pneumonic rotating arrangements may be provided. 
         [0081]    The rinsing fluid together with any dirt and remainders are then drained from the filter space  242  through outlet port  250  either to the environment or to a sewage line or recycling facility. 
         [0082]    Turning now to the example illustrated in  FIGS. 9 and 10  there is illustrated a rinsing mechanism generally designated  300  according to a different example, comprising a rinsing mechanism housing  302  configured for securing to the end supports  120  ( FIGS. 5 and 6 ), said housing configured with a rinsing fluid main line  304  extending between two end plates  306  (only one of which seen in  FIG. 10 ) and further configured with a hydraulic motor generally designated  312  configured for imparting a rinsing fluid distribution pipe  320  with reciprocal pivotal motion in direction of arrowed line  322 . It is appreciated that the hydraulic motor  312  may be articulated to the rinsing fluid distribution pipe  320  through the end piece  306  or by a reciprocating link designated  325  ( FIG. 9 ). Furthermore, the rinsing fluid distribution pipe may be reciprocated by any of a hydraulic, pneumatic or electric motor, or a combination thereof. 
         [0083]    Integrally extending from the distribution pipe  320  there is a plurality of jet emitting arms  328  being in flow communication with the space  330  of the distribution pipe  320 . Each of said arms is configured with an internal lumen  332  terminating at a jet emitting nozzle  336 . The arrangement is such that the arms are pivotally disposed near a periphery of the filtration cassettes and are configured for reciprocal pivotal displacement (in a turntable-arm resembling fashion). The length of each of the arms  328  is substantially the length of a filtration segment  20  such that when the jet emitting arms  328  are reciprocally displaceable (about arrowed line  322 ) between an innermost position where they reach to the collection pipe  108 , and an outermost position at the distal end of the filtration segment  20 , they rinse substantially the entire surface of the disc-like filtering assemblies. 
         [0084]    In operation, a rinsing fluid is applied through the supply line  304  to thereby operate the reciprocating hydraulic motor  312  and rinsing fluid is then emitted into the pipe  330  and through lumens  332  and then out through the nozzles  336  upon imparting pivotal reciprocal displacement thereto. 
         [0085]    Simultaneously, an electric/hydraulic/pneumonic motor rotates the filtering unit  100 , resulting in a fluid jet emitted against the coiled filtering threads  55  of the filtration segment  20  similar to the general concept as discussed in connection with reference to  FIG. 8D . 
         [0086]    While there have been shown several examples of the disclosed subject matter, it is to be understood that many changes may be made therein without departing from the spirit of the present disclosed subject matter, mutatis mutandis.