Abstract:
A multi-chamber magnetic filter is disclosed. The filter incorporates tubes that extend through a plurality of chambers that can contain a fluid to be filtered. Magnet assemblies are shuttled through the tubes and can be positioned within a chamber for use in removing ferromagnetic particles from a fluid flowing therethrough. Accumulated ferromagnetic materials can be readily purged from a chamber that does not have magnet assemblies located therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/455,831, filed on Mar. 19, 2003. The disclosure of the above application is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to magnetic filters, and more specifically to multi-chamber magnetic filters for cutting oil that incorporate a backwash feature.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention is directed to a multi-chamber magnetic filter. In one preferred form, the present invention provides a multi-chamber magnetic filter including a first chamber, a second chamber, a filter tube interposed at least partially through the first and second chambers and a magnetic assembly interposed within the filter tube and adapted for movement therein so as to be positioned within the first and second chambers.  
           [0004]    In another aspect, the present invention provides a method whereby a multi-chamber magnetic filter is adapted for filtering a working fluid within a first chamber. In yet another aspect of the present invention, provides a method whereby a multi-chamber magnetic filter is adapted for backwashing a filtered media from a first chamber.  
           [0005]    In a further aspect the present invention provides a method whereby a multi-chamber magnetic filter is adapted for simultaneously filtering a working fluid within a first chamber and backwashing a filter media from a second chamber. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0007]    [0007]FIG. 1 is a partial cut away side view of the magnetic filter of the present invention;  
         [0008]    [0008]FIG. 2 is a top view of the magnetic filter of FIG. 1;  
         [0009]    [0009]FIG. 3 is an exploded side view of the magnetic filter of FIG. 1;  
         [0010]    [0010]FIG. 4 is a side view of a magnetic assembly particularly suited for the magnetic filter of FIG. 1; and  
         [0011]    [0011]FIG. 5 is a piping schematic for the magnetic filter of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0013]    Referring to FIGS. 1 and 2, the magnetic filter  10  of the present invention is shown in a preferred embodiment to include a body formed of a top housing  12 , a bottom housing  14 , end caps  16 , filter tube assembly  18 , and magnet assemblies  20 . Top housing  12  and bottom housing  14  are geometrically similar and include a generally cylindrical shell  30 , mating flanges  32 , inlet  34 , outlet  36 , and backwash port  38  which form oil holding chambers  13  and  15 .  
         [0014]    As best seen in FIG. 3, filter tube assembly  18  includes an array of magnet holding members in the form of hollow filter tubes  40  having an external surface  42  and an internal surface  44 , and opposing ends  46 . The external surface  42  defines a portion of the oil holding chambers. As explained below, the hollow filter tubes are preferably made of non-ferrous materials which allow the passage of magnetic flux into the oil to be cleaned. Filter tubes  40  are interconnected adjacent opposing ends  46  by tube sheets  48 . Filter tubes  40  are also interconnected by a central tube plate  50 . Tube sheets  48  and tube plate  50  are generally circular sheets that are provided with apertures  52  to accommodate filter tubes  40 . Preferably, filter tubes  40  are circumferentially welded along external surface  42  to tube sheets  48  and tube plate  50 .  
         [0015]    Referring now to FIGS. 1 and 4, magnet assemblies  20  include a magnet portion  56  and end portions  58 . Preferably, end portions  58  have a thrust seal  60  coupled thereon. Thrust seal  60  is adapted to sealingly contact internal surface  44  of filter tubes  40 . Internal diameter D of filter tube  40  is adapted to accommodate the diameter of magnet portion  56 . In this manner, thrust seals  60  are adapted to provide some resistance to relative movement between magnet assemblies  20  and filter tubes  40  while allowing magnet assemblies  20  to shuttle within filter tubes  40 . While magnet assembly  20  can be manually shuttled within filter tube  40  using an actuation assembly, magnet assemblies  20  are preferably shuttled within filter tubes  40  with the use of a differential pneumatic pressure across thrust seal  60  as discussed below.  
         [0016]    As best seen in FIGS. 1 and 2, tube plate  50  is interposed between housings  12  and  14  as filter tubes  40  are positioned within housings  12  and  14 . Mating flanges  32  are bolted to tube plate  50  with gaskets  66  positioned therebetween although other coupling means may be employed. End caps  16  are coupled to mating flanges  32 . Preferably, end caps  16  are provided with an access port  70 . When assembled, top housing  12 , end cap  16 , and filter tube assembly  18  define a sealed top chamber  72 ; bottom housing  14 , end cap  16 , and filter tube assembly  18  define a sealed bottom chamber  74 ; and filter tube assembly  18  and end caps  16  define a magnet shuttle area  76  that includes the inside volume of filter tubes  40 .  
         [0017]    In operation, magnet assemblies  20  are preferably shuttled within filter tubes  40 . This can be accomplished using mechanical mechanisms such as screw or cable driven actuators or the application of a pressurized source of air to access port  70  of one end cap  16  while allowing an escape of fluid through access port  70  of the opposite end cap  16 . The length L of magnet assemblies  20  is preferably provided such that magnet assemblies  20  can be positioned within one housing  12 ,  14  while not exerting an appreciable magnetic force within the other housing  12 ,  14 . In this regard, when the magnet assembly  20  is positioned in one housing, magnetic flux from the assembly passes through the hollow filter tube  40  and into the oil being cleaned. It would be appreciated that while FIG. 4 illustrates a single magnet assembly  20  in a filter tube  40 , multiple magnet assemblies  20  can be employed within a single filter tube  40  to accomplish a similar result. It would also be appreciated that while FIG. 4 illustrates two thrust seals  60  coupled to magnet assembly  20 , magnet assembly  20  can be provided with any number of thrust seals  60 .  
         [0018]    Referring now to FIG. 5, magnetic filter  10  is illustrated with a preferred piping arrangement defining a system  78  which includes a plurality of control valves. A valve V 1 A interconnects system inlet  80  in fluid communication with inlet  34  of top chamber  72 . A valve V 2 A interconnects outlet  36  of top chamber  72  with a system outlet  82 . A valve V 3 A interconnects backwash port  38  of top chamber  72  with a system waste port outlet  84 . Valve V 4 A interconnects outlet  36  of top chamber  72  in fluid communication with a backwash connection  86 . Valve V 5 A interconnects inlet  34  of top chamber  72  in fluid communication with backwash connection  86 .  
         [0019]    Similarly, valve V 1 B interconnects system inlet  80  in fluid communication with inlet  34  of bottom chamber  74 . Valve V 2 B interconnects outlet  36  of bottom chamber  74  in fluid communication with system outlet  82 . Valve V 3 B interconnects backwash port  38  of bottom chamber  74  in fluid communication with system waste outlet  84 . Valve V 4 B interconnects outlet  36  of bottom chamber  74  in fluid communication with backwash connection  86  and valve V 5 B interconnects inlet  34  of bottom chamber  74  in fluid communication with backwash connection  86 .  
         [0020]    For filter mode operational setup of top chamber  72 , magnet assemblies  20  are positioned within top chamber  72 ; valves V 1 B, V 2 B, V 3 A, V 4 A, and V 5 A are closed; and valves V 1 A, and V 2 A are open. A working fluid containing ferromagnetic particles is introduced into system inlet  80  with sufficient pressure to maintain fluid flow to system outlet  82 . In this manner, the magnetic attractive force of magnet assemblies  20  cause at least a portion of the ferromagnetic particles to accumulate on external surface  42  of filter tubes  40  within top chamber  72 . Thus provided, the working fluid flow is both transverse and aligned with the direction of filter tubes  40 . Preferably, the working fluid is a cutting oil/cooling fluid emulsion although it would be envisioned that other fluids could be magnetically filtered with some degree of success. It would be appreciated that providing the inlet  34  at a lower elevation than outlet  36  would further promote the separation of heaver ferromagnetic particles from a cutting oil/cleaning fluid emulsion.  
         [0021]    When top chamber  72  is in an operating or standby filter mode, bottom chamber  74  can be backwashed to remove the ferromagnetic particles that have accumulated therein from a previous filter mode operation. For backwash mode setup of bottom chamber  74 , magnet assemblies  20  remain within top chamber  72  and valves V 1 B, V 2 B, V 3 A, V 4 A, V 5 A, V 1 A, and V 2 A remain in the valve positions indicated above. Valve V 3 B is open and a backwash fluid is introduced into bottom chamber  74  and allowed to drain through backwash port  38 . In this manner, the backwash fluid transports the accumulated ferromagnetic particles from bottom chamber  74  to system waste outlet  84  or a recycle location. It would be envisioned that the backwash fluid can enter bottom chamber  74  through valve V 3 B, V 4 B, V 5 B, or some combination thereof. It would also be envisioned that the working fluid pressure at system inlet  80  may be sufficient to allow the working fluid to enter through valve V 1 B and serve as the backwash fluid.  
         [0022]    Thus provided, magnetic filter  10  can filter ferromagnetic particles from a working fluid within a top chamber  72  when magnet assemblies  20  are positioned within top chamber  72  while bottom chamber  74  is backwashed. The flow of the working fluid can be re-routed to flow through bottom chamber  74  as magnet assemblies  20  are positioned within bottom chamber  74  to provide a continuous filtering capability with a sealed magnetic filter  10  without the need to shut down system  78  filtering operations to backwash the filtering chamber. It would be appreciated that the magnetic filters disclosed herein could be modified to include three or more chambers with a plurality of magnet assemblies to allow for filtering and/or backwashing simultaneously in more than one chamber. Further it is envisioned that the magnet assembly can take the form of a plurality of discreet magnetic members such as spherical balls.  
         [0023]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. For example, while the system shows the shuttling of magnetic materials is used to remove or reduce the magnetic flux in the oil, it is equally envisioned that materials can be interposed between the magnets and the oil within the hollow tubes to disrupt the magnetic flux. It is envisioned ferrous materials or a family of alloys known as mu metals can be used. Additionally, while metal magnetic bars are shown, it is envisioned that magnets can take any shape or can be electromagnets. Such variations are not to be regarded as a departure from the spirit and scope of the invention.