Abstract:
A filter element has first and second subelements providing increased media providing improved performance and packaging options. The first and second subelements provide first and second flow paths in parallel with each other along designated flow path portions.

Description:
BACKGROUND AND SUMMARY 
   The invention relates to filters, and more particularly high capacity filters. 
   Extended service intervals and lower filter restriction are two key performance parameters of a filtration system, including air filtration. The market also demands improved packaging options. Increased filter performance can provide similar performance in a smaller package size, or improved performance in similar sizes. It is further desirable to provide an improved performance filter element while allowing the use of a standard filter housing. This allows an end-user to select between a standard filter element version or a higher performance version, and use either version in a standard filter housing provided by the OEM (original equipment manufacturer). 
   The present invention arose during continuing development efforts directed toward improved filter performance as noted above. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a filter housing which may house a filter element in accordance with the present invention. 
       FIG. 2  is a sectional view taken along line  2 - 2  of  FIG. 1 . 
       FIG. 3  is a perspective view of a portion of  FIG. 1  with the housing cut away. 
       FIG. 4  is a sectional view taken along line  4 - 4  of  FIG. 3 . 
       FIG. 5  is like  FIG. 3  and shows another embodiment. 
       FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 5 . 
       FIG. 7  is like  FIG. 4  and shows another embodiment. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a filter  20  for filtering a fluid as shown at incoming arrow  22 , e.g. air or other fluids. In the case of air, the filter is an air cleaner including a cylindrical housing  24  extending axially along an axis  26  and having a tangential inlet  28  and having an outlet  30 ,  FIG. 2  for discharging clean filtered air as shown at arrow  32 , and for example as shown in U.S. Pat. No. 6,958,083, incorporated herein by reference. An annular filter element  34  in the housing receives dirty air from inlet  28  and delivers clean filtered air to outlet  30 . Air entering housing  24  through tangential inlet  28  as shown at arrow  22  flows along an interior surface  36  of housing  24  in a helical spiral pattern and then flows through filter element  34  including first and second subelements  38  and  40 , to be described, into hollow interior  42  and then flows axially leftwardly in  FIG. 2  through outlet  30  as shown at arrow  32 . Housing  24  is typically a two-piece plastic assembly provided by an upper housing section  44  and a lower housing section  46 , as in the noted incorporated &#39;083 patent, and joined by a twist and lock structure  48 , for example as shown in U.S. Pat. No. 6,402,798, incorporated herein by reference. Lower section  46  may have a dust ejection purge valve  50  for periodically discharging collected particulate due to the precleaning provided by the centrifugal separation afforded by the noted helical pattern, as is known, for example in the noted incorporated &#39;083 patent. A pressure tap  52  may be provided at outlet  30  for monitoring the pressure thereat, for in turn monitoring pressure drop across the filter, as is known. 
   Filter element  34 ,  FIG. 2 , extends axially along axis  26  between distally opposite first and second axial ends  54  and  56 . The filter element includes a first subelement  38  having a first flow path  58  therethrough from a first upstream face  60  to a first downstream face  62 , and a second subelement  40  having a second flow path  64  therethrough from a second upstream face  66  to a second downstream face  68 . Each subelement is preferably an annular member, and subelement  38  may taper slightly radially inwardly as it extends axially rightwardly in  FIG. 2 , and subelement  40  may be a frusto-conical member tapering radially inwardly as it extends axially leftwardly in  FIG. 2 . Flow paths  58  and  64  are in parallel with each other from inlet  28  to outlet  30 . Second flow path  64  has an upstream portion  70 ,  FIGS. 2-4 , flowing axially rightwardly at  72  along the noted first upstream face  60  then radially inwardly at  74  along the noted first axial end  54  of the filter element then axially leftwardly at  76  along the noted second upstream face  66 . The flow at  72  is between the filter element and an annular flange  78  extending axially leftwardly from the axial end  80  of housing section or cover  46 . The flow at  74  is between the axial end  54  of the filter element at endcap  82  and axial end  80  of housing cover section  46 , with guide structure provided along path  74 , to be described. The flow at  76  is into hollow interior  84  of subelement  40 . 
   First and second downstream faces  62  and  68  face each other. First and second upstream faces  60  and  66  face away from each other. First flow path  58  through first subelement  38  is along a first direction, namely radially inwardly. Second flow path  64  through second subelement  40  is along a second direction, namely radially outwardly. The noted second direction is opposite to the noted first direction. First and second downstream faces  62  and  68  face each other across a common gap  88  preferably along a rectilinear line therebetween. First and second flow paths  58  and  64  merge with each other in gap  88 . Upstream portion  70  of second flow path  64  defines a U-shape around common gap  88 . The U-shape has first and second legs  72  and  76  and a bight  74  therebetween. First leg  72  is radially spaced from common gap  88  by first subelement  38  therebetween. Bight  74  is axially spaced from common gap  88  by axial end  54  of the filter element therebetween. Second leg  76  is radially spaced from common gap  88  by second subelement  40  therebetween. 
   In the construction of  FIGS. 2-4 , endcap assembly  82  at first axial end  54  has radial guide channels therealong providing radial flow passages at  74  from first upstream face  60  to second upstream face  66 . First and second subelements  38  and  40  are attached to each other with a common endcap  82 , e.g. urethane or the like, providing the noted endcap assembly. The endcap assembly includes a plurality of axially extending standoffs  92  providing a respective plurality of radial flow passages  90  therebetween. The endcap assembly may also include a plurality of radially extending standoffs  94  providing a respective plurality of axial flow passages  96  therebetween from first upstream face  60  to the plurality of radial guide channels  90 . The endcap assembly may further include a plurality of grooves  98  along axial flow passages  96  for additional axial flow. 
     FIGS. 5-6  show another embodiment and use like reference numerals from above where appropriate to facilitate understanding. The noted endcap assembly includes a perforated cage  100  extending from the noted first axial end  54 . The perforated cage includes a sidewall  102  extending axially and radially along a taper from first axial end  54 . The flow path at  74  passes through the perforations or openings or louvers or slots  104  of the cage as shown at  106 . 
   In one embodiment, each of subelements  38  and  40  includes pleated filter media having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips, for example as shown by the following incorporated U.S. Pat. Nos.: 6,261,334; 6,383,244; 6,391,076; 6,416,561; 6,511,599; 6,641,637. In one embodiment, common endcap  82  spans radially across the entire axial end of each subelement and covers the inner and outer pleat tips of each,  FIGS. 4 ,  6 . In another embodiment,  FIG. 7 , which uses like reference numerals from above to facilitate understanding, common endcap  82   a  covers the inner pleat tips  110  of first subelement  38  and the outer pleat tips  112  of second subelement  40 , but not the outer pleat tips  114  of first subelement  38  nor the inner pleat tips  116  of second subelement  40 . Common endcap  82   a  has an outer perimeter  118  less than the outer perimeter of outer pleat tips  114  of first subelement  38 . Common endcap  82   a  has an inner perimeter  120  greater than the inner perimeter of inner pleat tips  116  of second subelement  40 . This embodiment enables use of alternate pleat sealing as in the above noted incorporated patents, including U.S. Pat. No. 6,391,076, allowing the ends of the filter to have open pleat tips, including the end of the outer subelement  38 , to reduce restriction to flow around the axial end of the filter element at  74 , which in turn reduces overall restriction and increases the utilization of subelement  40 . The other axial end of second subelement  40  at  112  is closed by endcap  82   a  which may likewise only extend partially along the axial ends of the pleats to again take advantage of the noted alternate pleat sealing technology of the noted incorporated patents, though endcap  82   a  may extend radially across the entire span between the inner and outer pleat tips of subelement  40 . 
   In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different configurations, systems, and method steps described herein may be used alone or in combination with other configurations, systems and method steps. It is to be expected that various equivalents, alternatives and modifications are possible within the scope of the appended claims.