Abstract:
A filtration apparatus for removing solids and particulates from a liquid stream flowing through a filter media. A magnet is located adjacent to the filter media and the liquid steam to attract metal particles in the liquid stream to the filter media. The magnet may be a rare birth magnet. A variable speed drive motor is coupled to a carrier supporting the filter media to advance the filter media through the liquid stream.

Description:
BACKGROUND 
       [0001]    The following description relates, in general, to flatbed type fluid filters. 
         [0002]    Filtration apparatus is used to remove solid contaminates from fluids used in manufacturing operations. In automobile assembly plants, the assembled sheet metal vehicle body is washed prior to painting operations. Other industrial operations involve machining of parts. The machined parts are washed to remove chips, cutting fluid residue, and other solids and particulate material. 
         [0003]    In order to conserve resources, the wash fluid is recycled. The fluid is passed through a filtration apparatus which removes solids and other particulate materials so that the cleaned fluid may be recycled for further use in the industrial operations. 
         [0004]    One type of filtration apparatus used in industrial operations is a flat-bed type filter in which a filter media in the form of a thin, porous strip is indexed through a chamber containing a reservoir of fluid from industrial operations. Gravity or pressure pulls the fluid through the filter media thereby removing solids and particulates from the fluid. The cleaned fluid is then recycled to the industrial operation. The solids and particulates collect on the filter media and are removed dirty as the filter media indexes out of the filtration apparatus. 
         [0005]    Due to the high volume of wash fluid that is passed through the filter media for cleaning, the filter media rapidly clogs with the solids and particulates removed from the industrial fluid. The filter media is frequently indexed to bring clean filter media into the chamber to continue to clean the wash fluid. The solids and particulates form a cake or residue in the filter media which retains the solids and particulates in the filter media as the filter media exits the chamber to a waste receptacle. 
         [0006]    Due to the porosity of the filter media, which may be as low as 10 microns, small particulates, particularly, metal particulates can pass through the filter media and then be recycled with the clean fluid back to the industrial operation. 
         [0007]    It would be desirable to improve a filtration process using a filter media to clean wash fluids by removing a greater portion of metallic particles from the wash fluids as the fluid passes through the filter media. 
       SUMMARY 
       [0008]    A filtration apparatus for removing solids and particulates from a fluid includes a filter media movable through a liquid stream, and a magnet positioned beneath the filter media at a location with respect to the liquid stream passing through the filter media to magnetically attract metal particles in the liquid stream to include the filter media. 
         [0009]    The filtration apparatus includes the housing having an inlet and an outlet. The filter media is movable through the housing. A fluid reservoir is formed in the housing and includes a fluid containment structure and a portion of the filter media. A portion of the filter media is positioned with respect to the fluid reservoir to filter solids and particulates from the liquid stream as the liquid stream flows from the fluid reservoir through the filter media. 
         [0010]    A fluid inlet is fluidically coupled to the housing to direct fluid to be cleaned into the housing. A fluid outlet is fluidically coupled to the housing to receive clean fluid after the fluid has passed through the filter media. 
         [0011]    A first rotatable roller shaft is disposed in the housing. An electric drive motor having a rotatable output is coupled to the first roller shaft for rotating the first roller shaft. The filter media is moved by the first roller shaft through the housing. 
         [0012]    The electric motor may be a variable speed motor for selectively varying the speed of movement of a filter media through the housing. 
         [0013]    A second rotatable roller shaft is spaced from the first roller shaft in the housing. The filter media is supported between the first and second roller shafts to define a filtering region on the filtering media between the first and second roller shafts in fluid flow communication with the fluid reservoir. 
         [0014]    A porous carrier belt is disposed in a closed loop around the first and second roller shafts. The carrier belt carries the filter media through the housing. 
         [0015]    A liquid level sensor is mounted in the housing and is responsive to the level of fluid in the reservoir in the housing. The sensor generates an output to activate the electric drive motor to incrementally advance at least a portion of the filter media into the liquid stream. 
         [0016]    The magnet may be a rare earth magnet. The magnet can be formed of stacked layers of magnetic material. 
         [0017]    A non-ferrous support is mounted in the housing adjacent to the filter media. The magnet mounted in the support. The support can be formed of stainless steel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0018]    The various features, advantages and other uses of a filtration apparatus with magnetic particulate attraction will become more apparent by referring to the following detailed description and drawing in which: 
           [0019]      FIG. 1  is a top perspective view of a gravity bed type filtration apparatus; 
           [0020]      FIG. 2  is a bottom perspective view of the filtration apparatus shown in  FIG. 1 ; 
           [0021]      FIG. 3  is an opposite side, bottom perspective view of the filtration apparatus shown in  FIGS. 1 and 2 ; 
           [0022]      FIG. 4  is a side-elevational view of the filtration apparatus and magnet shown in  FIG. 3 ; 
           [0023]      FIG. 5  is an enlarged, partial side-elevational pictorial representation showing the function of the magnet in the filtration apparatus depicted in in  FIG. 4 ; and 
           [0024]      FIG. 6  is a further enlarged, pictorial representation of the collection of small particulates by the magnet depicted in the  FIGS. 3-5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Referring now to the drawing, and particularly to  FIGS. 1-6 , there is depicted, by example, a flat-bed, gravity-type filtration apparatus  10  which may use an enhanced magnetic attraction particulate collection function described hereafter. The filtration apparatus  10  maybe, by example, a K-factor filter sold by the K-factor Filter Corporation, Ontario, Canada. 
         [0026]    The filtration apparatus  10  includes a housing  12  which defines an internal chamber. A fluid reservoir forming assembly is mounted in the housing  12  to form a fluid containment structure and includes a pair of large diameter circular discs  14  and  16  which are spaced apart and connected by the central shaft  18  for simultaneous rotation. The discs  14  and  16  have a solid construction with a peripherally mounted resilient seal  20  mounted about the entire periphery of each disc  14  and  16 . The seal  20  may be formed of any type of seal material rubber, such as polymeric, etc. 
         [0027]    A pair of roller shafts  22  and  24  are mounted at approximately diametrically opposed edges of the discs  14  and  16  and generally extend parallel to the shaft  18  connecting the discs  14  and  16 . The roller shafts  22  and  24  span the distance between the discs  14  and  16 . One of the roller shafts  22  and  24 , such as roller shaft  24  is coupled by a transmission or belt and sprocket to a rotative drive source, such as an electric drive motor  26 . 
         [0028]    A pair of idler shafts  28  and  30  are mounted in the lower portion of the housing  12 . The idler shafts  28  and  30  are freely rotatable as is the non-power driven roller shaft  22 . 
         [0029]    A filter media carrying assembly is provided for advancing the filter media through the housing  12  underneath a liquid stream of contaminated wash fluid. An endless carrier belt  40  is mounted in a closed loop about the roller shafts  22  and  24  and the idler shafts  28  and  30 . The carrier belt  40  is formed of a non-magnetic, non-ferrous material, such as stainless steel or plastic. The carrier belt  40  has an open mesh configuration to support the filter media  50  as well as to allow fluid passing through the filter media  40  to pass freely through the carrier belt  40 . The width of the carrier belt  40  is slightly greater than the distance between the outer surfaces of the discs  14  and  16 . 
         [0030]    The carrier belt  40  is movable through rotation of the powered roller shaft  24  by the drive motor  26 . The movement of the carrier belt  40  may be continuous or, as described in the following example, in an incremental, indexing manner. 
         [0031]    The filter media  50  is in the form of an elongated thin strip having a porosity, such as  10  microns, for example. The filter media  50  is unwound from a roll  52  rotatably mounted on one side of the housing  12 . The filter media  50  passes through an opening in a housing  12  over and between the roller shafts  22  and  24 . After passing over the roller shafts  24 , the filter media  50  passes through an exit opening in the housing  12  for collection in a waste receptacle  54 . The fiber media  50  is supported between the roller shafts  22  and  24  by the carrier belt  40 . 
         [0032]    Referring now to  FIG. 4 , the arrangement of the discs  14  and  16  and the roller shafts  22  and  24  forces the carrier belt  40  and the upper portion of the filter media  50  carried on the carrier belt  40  into an arcuate path between the roller shaft  22 , the disc  14  and  16  and the roller shaft  24 . The edge seal  20  on the discs  14  and  16  sealingly engages the edge portions of the filter media  50  to create a seal which forms a pool or reservoir  60  of fluid on top of the filter media  50  and between the lower portions of the disc  14  and  16 . 
         [0033]    Fluid to be cleaned is introduced into the housing  12  from an inlet conduit  62  via a fluid connection  64  to a header box  66  mounted in the housing  12 . The header box  66  has a generally horizontally extending, rectangular configuration which forces the fluid entering the housing  12  through the fluid connection  64  to be disbursed in a horizontal manner across the width of the spaced discs  14  and  16 . The fluid exits the header box  66  and flows in a turbulent manner into the bottom portion of the discs  14  and  16  where it is trapped in the reservoir  60  above the upper region  67  of the filter media  50 . Gravity pulls the fluid through the filter media  50 . As the fluid passes through the pores of filter media  50  in the upper region  67  of the path of the filter media  50 , the filter media  50  removes solids and particulates from the fluid thereby creating substantially clean fluid denoted by reference number  68  which exits the housing  12  through a coupling  70  and a discharge pipe or conduit  72  to a fluid recovery apparatus denoted generally by reference number  74 . 
         [0034]    During the continuous flow of the fluid through the housing  12  and the filter media  50 , the solids and particulates removed by the filter media  50  from the fluid collect on the upper surface of the filter media  50  and gradually close off the pores in the filter media  50 . This causes the fluid level within the reservoir  60  to rise as less fluid can pass through the remaining open pores in the upper region  67  of the filter media  50 . A float or liquid level sensor  70  is mounted in the housing  14  and is positioned to detect a predetermined height of fluid in the reservoir  60 . When this predetermined fluid height is detected by the liquid level sensor  70 , the liquid level sensor  70  sends a signal to the drive motor  26  which rotates the roller shaft  24  moving the carrier belt  40  and the filter media  50  in a counter-clockwise direction in the orientation shown in  FIGS. 1-3  and in a clockwise direction in the orientation shown in  FIG. 4 . 
         [0035]    The drive motor  26  moves the carrier belt  40  until the height of the fluid in the reservoir  60  falls below a predetermined level at which time the output signal from the level sensor  70  is removed causing power to be removed from the drive motor  50  thereby stopping rotation of the roller shaft  24  and resulting in halting of further advance of the carrier belt  40  and the filter media  50  through the housing  12 . 
         [0036]    By way of example, approximately  24  inches of filter media  50  is exposed in the upper filtering region  67  below the reservoir  60 . The drive motor  26  is activated until approximately six inches of clean, fresh filter media  50  is pulled from the roll  50  and moved into the housing  14  into a portion of the upper filtering region  66 . At the same time, the same length of filter media  50  moves outward from the upper filtering region  66  out of contact with the fluid in the reservoir  60 . Despite the upward incline in the movement of the filter media  50  from the upper clean filtering region  67  up, over and around the roller shaft  24 , the collected solids and particulates form a cake or coalesce into a scum which remains fixed on the filter media  50 . 
         [0037]    The advance of a new length of filter media  50  into the upper filter regions  67  immediately increases the number of open pores in the filer media  50  allowing additional quantities of fluid to pass from the reservoir  60  through the filter media  50 . This causes the height of the fluid level in the reservoir  60  to drop until the output signal from the liquid level sensor  70  ceases. 
         [0038]    It is possible due to the porosity of the filter media  50  for small metal particles resulting from various industrial machining or assembly operations to pass through the filter media  50 . To minimize the amount of metal particles which pass the upper filtering region  67  of the filter media  50 , a magnet assembly  80  is mounted in the housing  14  in a position to generate a magnetic field  86  over a portion of the reservoir  60  in the housing  12 . 
         [0039]    As shown in  FIGS. 4-6 , the magnet assembly  80  is mounted adjacent an edge portion of the reservoir  60  to enable the magnetic field  86  of the magnet assembly  80  to be substantially focused on the edge region of the fluid in the fluid reservoir  60  above the upper filtering region  67  where the metal particles  90  are moving within the turbulent motion of the fluid in the reservoir  60 . The magnetic field  86  attracts these metal particles  90  and draws them toward the filter media  50  at the edge portion of the upper cleaning region  67  and at the edge of the fluid reservoir  60 , where the metal particles  90  are collected by the filter media  50  and are retained by the cake or scrim of collected solid and particulate materials already formed on the filter media  50  in the upper filtering region  67 . 
         [0040]    The lines  88  in  FIG. 5  generally depict the direction that the magnetic field  86  generated by the magnetic assembly  80  draws the particles  90  toward the filter media  50 . 
         [0041]    The magnet assembly  80  includes a support  82  by way of example constructed as a U-shaped channel with one open side extending across the width of the reservoir  60  between the discs  14  and  16 . The support  82  is formed of a non-magnetic material, such as stainless steel, plastic, etc. 
         [0042]    The magnet  84  can be any type of permanent magnet capable of generating a magnetic field with sufficient strength to attract the small metal particles  90  in the fluid reservoir  60  toward the filter media  50 . By way of example only, high strength rare earth magnets of 13,000-14,000 gauss magnetic force are mounted in the support  82 . Although the magnet  84  may be formed as a single solid block or multiple end to end positioned blocks, it is also possible to form the rare earth magnet  84  of individual layers which are arranged in a stack within the support  82 . 
         [0043]    The selection of the magnetic field strength of the magnet  84  is made by taking into consideration along with the amount of indexing movement of the filer media  50  in each indexing cycle as well as the speed of movement of the filter media  50  to enable the additional metal particles  90  drawn by the magnet  84  and collected on the filter media  50  in a larger accumulation as shown by reference number  92  in  FIG. 6 , to be retained on the filter media  50  despite the upward inclined path of movement of the filter media  50  from the edge of the discs  14  and  16  to the roller shaft  24 . 
         [0044]    For this reason, the drive motor  26  can be a variable speed drive motor  26 . This enables the speed of the drive motor  26  and thereby the speed of advance of the filter media  50  to be adjusted with respect to the magnetic field strength of the magnet  84  to enable most of the additional metal particles  90  collected on the filter media  50  to be retained on the filter media  50  as the filter media  50  moves up the incline and around the roller shaft  24 ; as well as, at the same time, allowing release of the metal particles  90  on the filter media  50  from the magnetic field  86  generated by the magnet  84  as the filter media  50  indexes in the next cycle of the movement.