Abstract:
An end cap of a filter element has canted fins in an annular space between a filter element and filter housing for imparting a rotary motion to a fluid prior to the fluid passing through the filter element. The end cap includes a plurality of axially extending legs upstream of the fins, which legs engage a nutplate. Spaces between the legs provide an inlet allowing dirty fluid to flow to the outside surfaces of the filter element. The fins remove large particles from the fluid by centrifugal force so that large particles do not add to the contaminant load in the filter elements.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to a spacer element and a filter assembly utilizing the spacer element. More particularly, the present invention is directed to a spacer element and a filter assembly utilizing the spacer element wherein the spacer element is used in filter assemblies in which liquid to be filtered is given a cyclonic path around at least one annular filter element before passing through the filter media of the filter element in order to remove contaminants. 
     BACKGROUND OF THE INVENTION 
     Filter cartridges used for filtering fluids such as lubricating oil can be arranged with a full flow filter element and a bypass filter element, the bypass filter element being stacked on the full flow filter element with the fluid flowing radially through the filter elements into hollow cores thereof and then axially out of the cartridges. 
     This arrangement is widely employed to filter lubricating oil used in internal combustion engines. Engine wear, specifically piston ring wear, is directly related to the amount of actual filtration of lubricating oil by both full flow and bypass filters which is mixed after filtration. It has been found that by combining filtration provided by a full flow filter element with that of a bypass filter element substantially reduces engine wear as compared to using only full flow filtration. Moreover, by using a combination of full flow and bypass flow lubricating oil, service intervals can be increased so that maintenance expense is reduced. Maintenance expense is a major consideration in the total expense of operating a vehicle. This is, of course, is a major concern for fleets of vehicles, such as the fleets operated by trucking companies. In addition, by keeping lubricating oil clean, it can remain in engines longer and does not have to be recycled at shorter intervals. Consequently, environmental concerns due to vast amounts of used lubricating oil are reduced because less used oil must be recycled. It is therefore beneficial to enhance the performance of lubricating oil cartridges which utilize both full flow filter elements and bypass filter elements. 
     Arrangements have evolved wherein filter mounting bases, which are integral with engine mounting blocks, now have increased diameters with dirty inlet oil flowing though a plurality of radially positioned, spaced ports and with filtered clean oil flowing axially through a neutral outlet port. Increased diameter filter mounting bases require threaded nutplates of increased diameter which has resulted in modified filter configurations. In addition, it has been found that imparting a cyclonic rotation to dirty inlet oil increases the capacity and efficiency of the annular filter media used in the spin-on filters. 
     In that spin-on filter elements are designed to be replaced at specified intervals, it is worthwhile to design these filters to reduce the expense of their manufacturer while maintaining their reliability. Expense and reliability are of considerable importance with filters that may be used with diesel engines because it is necessary to change these filters at shorter intervals than filters used for gasoline engines. 
     SUMMARY OF THE INVENTION 
     In view of the aforementioned considerations, the present invention is directed to a filter assembly for filtering a fluid, wherein the filter assembly comprises a cylindrical housing having an annular wall defining a cylindrical space, a closed end and an open end. An end plate assembly partially closes the open end and provides a port for receiving a portion of a filter mounting base. At least the first annular filter element is disposed in the housing and supported in the end plate assembly. A spacer element is disposed between the end plate assembly and the filter element wherein the spacer element comprises a disk having a central opening therethrough for receiving the standpipe of the filter mounting base and an axially extending peripheral flange having an array of projecting radial fins which are axially canted thereon for imparting a cyclonic motion to the fluid being filtered. A plurality of axially extending legs engage the end plate arrangement in order to keep the filter element in spaced relation thereto, whereby the fluid flows between the legs, over the fins, through the filter element and out of the standpipe received in the opening through the disk. 
     In a preferred embodiment of the invention, the spacer element is unitary with an end cap used to close one end of an filter media used in the filter element. In this preferred embodiment, the aforedescribed spacer element becomes part of the filter element since it comprises one of the end caps of the filter element. 
     The present invention is also directed to end cap for used with an annular filter media to form a filter element for mounting in a cylindrical housing to provide a filter element for filtering a fluid, wherein the housing is closed by an end plate assembly. The end cap comprises a disk having a central opening therethrough for receiving a standpipe, the disk closing an end of the filter media. An axially extending peripheral flange is on the disk, the axially extending peripheral flange having an array of radially projecting fins which are axially canted thereon for imparting a spiral motion to the fluid being filtered. The axially extending peripheral flange cooperates with the disk to provide a pocket for receiving the end of the annular filter media. A plurality of axially extending legs engage the end plate assembly in order to keep the filter element in spaced relation thereto, whereby the fluid flows between the legs, over the fins, through the filter media and out of the standpipe received in the opening through the disk. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
         FIG. 1  is a side view, partially in elevation, of a filter configured in accordance with the principals of the present invention; 
         FIG. 2  is an enlarged elevation of a portion of  FIG. 1 ; 
         FIG. 3  is a view similar to  FIG. 2 , but not including a filter mounting base and standpipe; 
         FIG. 4  is a side perspective view with portions of the filter housing deleted showing a spacer configured in accordance with the principals of the present invention supporting the filter element on a nutplate, in accordance with the principles of the present invention; 
         FIG. 5  is a perspective view of a spacer configured in accordance with the principles of the present invention; 
         FIG. 6  is a side view partially in elevation of the spacer of  FIG. 5 ; 
         FIG. 7  is an end view of the spacer of  FIG. 5  taken along lines  7 — 7  of  FIG. 5 ; 
         FIG. 8  is an enlarged view of a portion of the spacer of  FIGS. 5-7 ; 
         FIG. 9  is a top perspective view of an end plate assembly according to the present invention, and 
         FIG. 10  is a bottom perspective view of the end plate of FIG.  9 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-3 , there is shown a filter cartridge  10 , configured in accordance with the principles of the present invention, wherein the filter cartridge  10  includes a canister housing  12  having a first end  14  and a second end  16  which is domed. The first end  14  includes an end plate assembly  18  which includes an endplate  20  welded to a nutplate  22  and is coaxial with an axis  24  of the filter canister. The end plate assembly  18  is retained at the first end  14  of the housing  12  and within the canister by a peripheral portion  25  of the end plate  20  which is enfolded with an end portion  26  of the housing  20 . Preferably, the filter cartridge  10  is mounted with the axis  24  extending at least generally vertically and the first end  14  of the housing being the top end and second end  16  of the housing being the bottom end. 
     The canister  12  is configured in accordance with a preferred embodiment of the invention as a filter canister for filtering lubricating oil used in internal combustion engines. The nutplate  22  has internal threads  30  which are threaded onto threads  31  of a threaded stud  32  of a filter mounting base  33  projecting from an engine (not shown), through which dirty unfiltered oil enters the filter cartridge  10  through a plurality of radially spaced openings  34  in the filter mounting base  33  and clean filtered oil returns to the engine through a central standpipe  35 . The plurality of radially spaced inlet openings  34  are isolated from the standpipe  35  and allow lubricating oil to flow into an annular space  36  which is defined by a filter element spacer  37 , according to the presnt invention, that abuts the nutplate  22  and surrounds the threaded stud  32  which has the thread  31  on the outer surface thereof. 
     Urged against the spacer  37  is a first filter element  40  which is a full flow filter element. The first filter element  40  has a diameter less than the diameter of the housing  12  so that an annular inlet channel  42  is created between the filter element  40  and the inner surface of the wall of the canister housing  12 . The first filter element  40  is comprised of an annular small particle filter media  44  having a first hollow core  46  therein and having first and second ends. The first end is closed by the spacer  37  which is also a first end cap  48  and the second end is closed by a second end cap  50 . The spacer  37  is bonded by a layer  49  of plastisol or other adhesive to become the first end cap  48  integral with the filter media  44  to thus form the filter element  40  which includes the second end cap  50  and a perforated center tube  51 . The first end cap  48  (comprised of the spacer  37 ) is urged against the nutplate  22 , while the second end cap  50  is annular defining a hole  52  therethrough, which hole receives a first flow-altering element  56  disposed internally with respect to the filter elements  40  and  70 . The first flow deflecting element  56  has a first end  58  that projects into the first hollow core  46  and a second end  60  which projects below the first filter element  40  to impart a non-axial component to clean fluid flowing out of the second filter element  70 . The flow deflecting element  56  has a radially projecting flange  62  which abuts the flange  50  so as to be sandwiched between the first filter element  40  and a second filter element  70 . 
     The second filter element  70  which is stacked with the first filter element  40  and has a portion of the annular inlet channel  42  therearound. The second filter element  70  has an annular sludge removing filter media  72  which defines therein a second hollow core  74 , which second hollow core  74  communicates with the first hollow core  46  through the flow-altering element  56 . The second filter element  70  has a first end closed by a first annular end cap  76  which has an opening  78  therethrough which receives the second end  60  of the flow-altering element  56  and abuts the bottom surface of the radial flange  62  so as to clamp the flow-altering element in place with the second end  60  of the flow-altering element received within the hollow core  74  of the first annular filter media  72 . At the second end of the sludge removing filter media  72  is a second end cap  80  which is configured as a closed disk without a center opening. The second end cap  80  is engaged by a coil spring  82  which abuts the closed second end  16  of the canister  12  to urge the second filter element  70  against the radial flange  62  of the flow-deflecting element  56  that in turn abuts the first filter element  40  and holds the first filter element against the nutplate  22 . 
     Dirty lubricating oil  85  flowing in the annular inlet channel  42  and which does not flow radially through the first filter media  44 , flows radially through the second filter media  72  and then through the first flow-deflecting element  56 . 
     Further details of the flow-altering element  56  are set forth in U.S. patent application Ser. No. 09/398,459 filed on Sep. 17, 1999 now U.S. Pat. No. 6,423,225 and incorporated herein in its entirety by reference. 
     The aforedescribed arrangement is especially useful with lubricating oil filters wherein the first filter element  40  is a full flow filter element and the second filter element  72  is a bypass filter element. It has been found desirable to mix the lubricating oil which has been filtered by the bypass filter element  72  with the filter oil filtered by the full flow filter element  40  before returning the oil to the engine in the flow stream  100  passing through the central standpipe  35 . This arrangement is especially useful when the second filter element  72  which forms the bypass element is arranged for recycling sludge generated by the internal combustion engine while the full flow filter element  40  traps only particles or dirt. Consequently, as the oil stream undergoes many passes through the filter cartridge  10 , the first filter element  40  traps primarily dirt or particulate matter in the filter media  44 , while the second filter element  70  traps primarily sludge in the second filter media  72 . Thus, the first filter media  44  has an increased dirt-holding capacity because it does not also trap sludge, thereby rendering the entire filtering system provided within the cartridge  10  with an increased capacity and efficiency that improves lubricating oil filtration and substantially increases intervals between oil filter changes. 
     Referring now to  FIG. 4 , it is seen that the spacer  37  is preferably a unitary structure providing the end cap  48  for the filter element  40 . Preferably the spacer  37  which form end cap  48  is molded of a resinous material but it can also be made of metal. The spacer  37  has an external array  110  of fins  112  that provide a second deflector positioned in the annular inlet channel  42  just down stream of inlet openings  114  through the spacer  37  forming the first end cap  48 . As is seen in  FIG. 1 , the array  110  of fins  112  imparts a rotational motion to the fluid prior to the fluid entering the first filter element  40  so that the fluid spirals in the direction of arrows  120  around the first filter element  40  causing relatively large particles to migrate centrifugally toward the inner surface  124  of the cylindrical wall  126  comprising the housing  12 , instead of passing through the small particle filter media  44  of the first filter element  40 . Accordingly, it is mostly smaller particles of dirt or contaminant that pass through the first filter element  40 . 
     The fluid continues to spiral as it moves in the annular inlet space  42  toward the second filter element  70 , keeping a substantial quantity of large particles away from the second filter element so that the second filter element mainly traps sludge in the sludge removing filter media  72 . A substantial portion of the large particles remain suspended in the oil near the surface  124  of the canister wall  126  and never pass into the second filter element  70 . 
     The large particles which have avoided filter elements  40  and  70  pass through a gap  130  between the end cap  80  of the second filter element  70  and the surface  124  of wall  126 . The particles then become trapped in a chamber  134  defined by the domed second end  16  of the housing  12 . The gap  130  is maintained by the spring  82  which urges the second filter element  70  against flange  62  of the flow deflecting element  56 , which in turn abuts the first filter element  40  to urge the first filter element against the nutplate  22 . Since the chamber  134  is beneath the second filter element  70 , the heavy particles settle out and accumulate against the inner surface of the domed end  16 . 
     As is seen in  FIG. 4 , the array  110  fins  112  is preferably unitary with an axially projecting peripheral flange  140 , the fins being disposed at an angle of approximately 45° with respect to the axis  24  of the filter canister  10 . 
     Referring now mainly to  FIGS. 4-8 , it is seen that the first end plate  48  which provides the spacer  37  provides a pocket  145  for receiving the end portion of the filtermedia  44  (FIGS.  1 - 4 ). The pocket  145  is formed by the axially projecting peripheral flange  140  and an annular disk  146  unitary with the flange. The disk  146  has a central opening  148  therethrough for receiving the standpipe  35  of  FIGS. 1 and 2 . Around the central opening  148 , there is an inner seal  149  which has an axially extending radially facing sealing surface  150  for sealing between the standpipe  32  and filter element  40  so as to isolate the hollow core  46  of the filter element from the annular inlet space  36  (FIGS.  1  and  2 ). 
     The inlets  114  for dirty oil are spaces between legs  152  projecting axially form the axially projecting flange  140 . Each leg  152  has an inwardly facing notch  154  for receiving the edge portion  156  of a lip  158  extending axially from the nutplate  22  (see FIG.  4 ). 
     As is best seen in  FIGS. 9 and 10 , the end plate assembly  18  has two components, the end plate  20  and the nutplate  22  which are spot welded to one another to form an integral unit. The end plate  20  has a groove  162  therein for receiving a gasket  164  which seals with a land  166  on the filter mounting base  33  (see  FIG. 1 ) and is bendable so that the peripheral portion  25  thereof is bent into a J-shape enfolded with the end portion  26  of the housing  12  to permanently join the housing and the end plate  20  together. The nutplate  22  has a radially extending portion  170  which is welded to the end plate  20  to provide the end plate assembly  18  as well as the lip  158  formed by an axially extending portion having the internal threads  30  thereon for threading onto the externally threaded stud  32  of the filter mounting base  33  (see FIGS.  1  and  2 ). The axially extending lip  158  is directly engaged by the notches  154  in the legs  152  extending from the first end cap  48  which forms the spacer  37 . 
     From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.