Patent Publication Number: US-2021178309-A1

Title: Variable efficiency filtration media

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/208,412, entitled “VARIABLE EFFICIENCY FILTRATION MEDIA,” filed on Aug. 21, 2015 and the contents of which herein incorporated by reference in the entirety and for all purposes. 
    
    
     TECHNICAL FIELD 
     The present application relates to filter media. 
     BACKGROUND 
     Internal combustion engines generally combust a mixture of fuel (e.g., gasoline, diesel, natural gas, etc.) and air. Lubrication oil is also supplied to the engine to lubricate the various moving components of the engine. Either prior to entering the engine or during engine operation, the intake air, fuel, lubrication oil, and other fluids are typically passed through filtration systems to remove contaminants (e.g., dust, water, oil, etc.) from the fluids. The filtration systems include filter elements having filter media. As the fluid passes through the filter media, the filter media removes at least a portion of the contaminants in the fluid. Each filter element has an associated filtration efficiency. The filtration efficiency is a numerical representation of the filter element&#39;s effectiveness in removing contaminants from the fluid. The filtration efficiency of a filter element can vary over time. The efficiency of the filter element can be impacted by the design of the filter element (e.g., panel, pleated, non-pleated, cylindrical, membrane, etc.), the design of the filtration system, the operating conditions of the filtration system, and the utilized filter media (e.g., paper, fiberglass, polyester, foam, nanofiber, etc.). 
     Certain filtration systems incorporate multiple filter elements having different types of filter media to balance filtration efficiency, filter cartridge longevity, and cost. Such filters are also typically a combination of different filter elements having different filtering characteristics or add an additional higher efficiency filter cartridge to an existing standard efficiency filter cartridge. For example, as shown in  FIG. 1 , a conventional filtration system  100  utilizes two separate filter cartridges  102  and  104  in a parallel flow filter design. Each of the two filter cartridges  102  and  104  utilizes a different filter media having different filtration efficiencies. The first filter cartridge  102  is a standard efficiency filter cartridge having a pleated filter media. The second filter cartridge  104  is an alternative efficiency (e.g., higher efficiency than the standard efficiency) filter cartridge having a different pleated filter media. Fluid to be filtered flows through either the first filter cartridge  102  or the second filter cartridge  104  due to the parallel design of the filtration system  100 . This arrangement requires four endcaps  106 , two center tubes  108 , two filter media packs, and two seals  110 . The number of required parts for a parallel flow multiple filtration system increases the cost of the filtration system and presents an increased amount of failure points (e.g., leak points in the filtration system). 
     Flow through the above described parallel flow dual element filter is split between the two filter cartridges  102  and  104  based on a number of factors. For example, the amount of fluid flowing through the first filter cartridge  102  versus the amount of fluid flowing through the second filter cartridge  104  may be affected by the openings between endplates, the flow orifice between the two filter cartridges  102  and  104 , the media permeability (i.e., the media&#39;s resistance to flow), and the like. Accordingly, managing and maintaining the flow split between the two filter cartridges  102  and  104  is difficult and requires manipulation of various parameters of the filtration system  100 . 
     SUMMARY 
     An example embodiment relates to a filter cartridge. The filter cartridge includes a first endplate, a second endplate, and a filter media positioned between the first endplate and the second endplate and spanning an axial length between the first endplate and the second endplate. The filter media has a variable filtering efficiency that varies across the axial length. The filter media includes a first filter media portion having a first filtering efficiency and a first filter media axial length spanning the axial length. The filter media also includes a second filter media portion having a second filtering efficiency. The second filter media portion is coupled to the first filter media portion and spans a second filter media axial length. The second filter media axial length is less than the first filter media axial length of the filter media, thereby creating a first zone of the filter media and a second zone of the filter media. The first zone includes only the first filter media portion, and the second zone including both the first filter media portion and the second filter media portion. 
     Another example embodiment relates to filter media. The filter media includes a first filter media portion having a first filtering efficiency. The first filter media portion spans a first filter media width (also referred to as a slit width in some specific implementations). The filter media further includes a second filter media portion having a second filtering efficiency. The second filter media portion is coupled to the first filter media portion and spans a second filter media width. The second filter media width extends in the same direction as the first filter media width. The second filter media width is less than the first filter media width, thereby creating a first zone of the filter media and a second zone of the filter media. The first zone including only the first filter media portion, and the second zone including both the first filter media portion and the second filter media portion. 
     A further example embodiment relates to filter media. The filter media includes a first filter media portion having a first filtering efficiency and a first filter media width. The filter media includes a second filter media portion having a second filtering efficiency and a second filter media width. The second filter media portion is coupled to the first filter media portion, thereby forming an overlap zone having both the first filter media and the second filter media. The first filter media and the second filter media combining to have a combined width that is smaller than a sum of the first filter media width and the second filter media width. 
     These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the several drawings described below. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows a partial cutaway view of a prior art filtration system. 
         FIGS. 2A through 2C  show top views of exemplary variable efficiency filter media. 
         FIG. 3A  shows a perspective view of the variable efficiency filter media of  FIG. 2A  pleated and formed into a cylindrical shape. 
         FIGS. 3B through 3D  show perspective views of filter elements including the filter media of  FIGS. 2A through 2C . 
         FIG. 4  shows a perspective view of a filter cartridge  400  is shown according to an exemplary embodiment. 
         FIG. 5  shows a system diagram of a variable efficiency filter media manufacturing system according to an exemplary embodiment. 
         FIG. 6  shows a system diagram of a variable efficiency filter media manufacturing system according to another exemplary embodiment. 
         FIG. 7  shows a system diagram of a co-pleating system that pleats the variable efficiency filter media formed by the system of  FIG. 5  or  FIG. 6 . 
         FIG. 8  shows a system diagram of a pleated variable efficiency filter media manufacturing system according to another exemplary embodiment. 
         FIG. 9  shows a single sheet of standard filter media being folded over itself to create a variable efficiency filter media. 
         FIG. 10  shows two sheets of standard filter media being overlapped to form a variable efficiency filter media. 
         FIG. 11  is a graph plotting improved efficiencies of the described variable efficiency filter media. 
         FIG. 12  is a graph showing changes of filtering efficiency over time for various filter media. 
         FIG. 13  is a graph showing pressure drop over time for various filter media. 
         FIG. 14  is a cross-sectional view of a filter cartridge having a variable efficiency filter media according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS 
     Referring to the figures generally, a variable efficiency filter media is described. The variable efficiency filter media is a composite media foamed of at least two different types of filter media, such as a standard efficiency media and a high efficiency media. In some arrangements, the standard efficiency media forms a structural backbone for holding the other, higher efficiency media. Accordingly, the variable efficiency filter media has at least two different efficiency levels. The different efficiency levels can be spread across different zones. The variable efficiency filter media permits the efficiency ratio of each zone to be adjusted within a single filter element thereby allowing the filter element to meet various filter performance requirements. The filter media types for both the standard media and the high efficiency media can be made from spun media, melt blown media, nanofiber media, micro-glass media, cellulose media, carded staple fiber media, and the like. The variable efficiency filter media may be produced by any of an air laid process, a wet laid process, a lamination process, a pleating process, an ultrasonic bonding process, or the like. 
     Referring to  FIGS. 2A through 2C , exemplary variable efficiency filter media are shown. As shown in  FIG. 2A , a top view of a sheet of variable efficiency filter media  200  is shown according to an exemplary embodiment. The variable efficiency filter media  200  includes a first filter media portion  202 . The first filter media portion  202  has a standard filtering efficiency. As used herein, the phrase “standard filtering efficiency” means a baseline filtering efficiency that has its overall filtering efficiency increased with additional filter media to achieve a variable filtering efficiency. The first filter media portion  202  may be spun media, melt blown media, nanofiber media, micro-glass media, cellulose media, carded staple fiber media, or the like. In some arrangements, the first filter media portion  202  forms a structural backbone for the variable efficiency filter media  200 . The first filter media portion  202  spans the entire filter media width (i.e., the axial length of the variable efficiency filter media  200  when arranged in a filter element) across the width of the variable efficiency filter media  200 . As described in further detail, subsequent filter media layers and/or sections may be attached to the first filter media portion  202  to form zones of higher filtering efficiency within the variable efficiency filter media  200 . 
     The variable efficiency filter media  200  includes a second filter media portion  204 . The second filter media portion  204  may be spun media, melt blown media, nanofiber media, micro-glass media, cellulose media, carded staple fiber media, or the like. The second filter media portion  204  has a different filtering efficiency than the first filter media portion  202 . In some arrangements, the second filter media portion  204  has a higher filtering efficiency than the first filter media portion  202  (e.g., by compressing/calendaring the second filter media portion  204  to zones within the first filter media portion  202  to increase the efficiency of the first media  202  during production). The second filter media portion  204  is connected to and coupled to the first filter media portion  202  via an air laid process, a wet laid process, a lamination process, a pleating process, an ultrasonic bonding process, or the like. As used herein, when two filter media portions or layers are coupled to each other, the second filter media layer, for example, may be combined with, integrated with, overlaid onto, sprayed over, formed onto, underlain onto, or otherwise connected to the first filter media. In addition or alternatively, when two filter media portions or layers are coupled to each other, the first filter media type may be manufactured in a first orientation (e.g., having fibers or pleats in a first direction, such as horizontal with respect to gravity) and positioned in a second orientation with respect to the second filter media (e.g., having fibers or pleats in a second direction, such as vertical with respect to gravity). The second filter media portion  204  may be sealed to the first filter media portion  202  at an edge of the second filter media portion  204 . The use of an ultrasonic bonding process additionally provides for a differential pressure across a gradient of the variable efficiency filter media. Additionally, to assist with manufacturing via the ultrasonic bonding, indicators can be incorporated onto the ultrasonic bonding anvil drum to give visual assistance for subsequent manufacturing process (e.g., making it easier for the manufacturing line technician to visually see top and bottom portions of the media roll or pleated media packs). 
     The second filter media portion  204  spans across a distance less than the filter media width (i.e., the axial length of the variable efficiency filter media  200 ) of the variable efficiency filter media  200 . Accordingly, the variable efficiency filter media  200  has two separate zones of filtering efficiency: a first zone having only the first filter media portion  202  and a second zone having both the first filter media portion  202  and the second filter media portion  204 . Each of the two zones has a different filtering efficiency. The overall efficiency of the variable efficiency filter media  200  can be tuned by adjusting the widths of each strip of filter media and by selecting appropriate filter media for each of the strips. However, as described in more detail with respect to  FIGS. 2B and 2C , multiple efficiency layers/areas/zones or a gradient structure working together to provide one optimized filtering efficiency are possible. 
     Referring to  FIG. 2B , a top view of a sheet of three-zone variable efficiency filter media  210  is shown according to an exemplary embodiment. Similar to the two-zone variable efficiency filter media  200 , the three-zone variable efficiency filter media  210  also includes a base of the first filter media portion  202  and a strip of the second filter media portion  204 . Additionally, the variable efficiency filter media  210  includes a strip of a third filter media portion  206 . The third filter media portion  206  has a different filtering efficiency than the first filter media portion  202  and the second filter media portion  204 . The third filter media portion  206  is coupled to the second filter media portion  204  (which is already coupled to the first filter media portion  202 ) via an air laid process, a wet laid process (e.g., by compressing/calendaring the third filter media portion  206  to zones within the second filter media portion  204  to increase the efficiency of the first and second media  202  and  204  during production), a lamination process, a pleating process, an ultrasonic bonding process, or the like. The third filter media portion  206  may be sealed to the second filter media portion  204  at an edge of the third filter media portion  206 . The third filter media portion  206  spans across a distance less than the filter media width across the width of the variable efficiency filter media  210 . The third filter media portion  206  spans a third filter media width that is less than the second filter media width, such that a portion of the first filter media  202  is exposed, a portion of the second filter media  204  is exposed, and the entirety of the third filter media  206  is exposed. The widths of the strips of the first, second, and third filter media portions  202 ,  204 , and  206  can be the same or different. In this embodiment, the variable efficiency filter media  210  has three separate zones of filtering efficiency: a first zone having only the first filter media portion  202 , a second zone having both the first filter media portion  202  and the second filter media portion  204 , and a third zone having the first filter media portion  202 , the second filter media portion  204 , and the third filter media portion  206 . Each of the three zones has a different filtering efficiency. The overall efficiency of the variable efficiency filter media  210  can be tuned by adjusting the widths of each strip of filter media and by selecting appropriate filter media for each of the strips. 
     In an alternative arrangement, the third filter media portion  206  is coupled to and directly connected to the first filter media portion  202  via an air laid process, a wet laid process (e.g., by compressing/calendaring the third filter media portion  206  to zones within the first filter media portion  202  to increase the efficiency of the first media  202  during production), a lamination process, a pleating process, an ultrasonic bonding process, or the like. The third filter media portion  206  spans across a distance less than the filter media width across the width of the variable efficiency filter media  210 . In this arrangement, the third filter media portion  206  may be sealed to the first filter media portion  202  at an edge of the third filter media portion  206 . The widths of the strips of the first, second, and third filter media portions  202 ,  204 , and  206  can be the same or different. In this embodiment, the variable efficiency filter media  210  has three separate zones of filtering efficiency: a first zone having only the first filter media portion  202 , a second zone having both the first filter media portion  202  and the second filter media portion  204 , and a third zone having both the first filter media portion  202  and the third filter media portion  206 . Each of the three zones has a different filtering efficiency. The overall efficiency of the variable efficiency filter media  210  can be tuned by adjusting the widths of each strip of filter media and by selecting appropriate filter media for each of the strips. 
     Referring to  FIG. 2C , a top view of a sheet of four-zone variable efficiency filter media  220  is shown according to an exemplary embodiment. Similar to the three-zone variable efficiency filter media  210 , the four-zone variable efficiency filter media  220  also includes a base of the first filter media portion  202 , a strip of the second filter media portion  204 , and a strip of the third filter media portion  206 . Additionally, the variable efficiency filter media  220  includes a strip of a fourth filter media portion  208 . The fourth filter media portion  208  has a different filtering efficiency than the first filter media portion  202 , the second filter media portion  204 , and the third filter media portion  206 . In a similar manner as described above with respect to filter media  210 , the fourth filter media portion  208  is coupled to the third filter media portion  206  (which is already coupled to the second filter media portion  204 ) via an air laid process, a wet laid process, a lamination process, a pleating process, an ultrasonic bonding process, or the like. The fourth filter media portion  208  may be sealed to the third filter media portion  206  at an edge of the fourth filter media portion  208 . The fourth filter media portion  208  spans across a distance less than the filter media width across the width of the variable efficiency filter media  220 . The fourth filter media portion  208  spans a fourth filter media width that is less than the third filter media width, such that a portion of the first filter media  202  is exposed, a portion of the second filter media  204  is exposed, a portion of the third filter media  206  is exposed, and the entirety of the fourth filter media  208  is exposed. The widths of the strips of the first, second, third, and fourth filter media portions  202 ,  204 ,  206 , and  208  can be the same or different. In this embodiment, the variable efficiency filter media  220  has four separate zones of filtering efficiency: a first zone having only the first filter media portion  202 , a second zone having both the first filter media portion  202  and the second filter media portion  204 , a third zone having the first filter media portion  202 , the second filter media portion  204 , and the third filter media portion  206 , and a fourth zone having the first, second, third, and fourth filter media portions  202 ,  204 ,  206 , and  208 . Each of the three zones has a different filtering efficiency. The overall efficiency of the variable efficiency filter media  220  can be tuned by adjusting the widths of each strip of filter media and by selecting appropriate filter media for each of the strips. 
     In an alternative arrangement, the fourth filter media portion  208  is coupled to the first filter media portion  202  via an air laid process, a wet laid process (e.g., by compressing/calendaring the fourth filter media portion  208  to zones within the first filter media portion  202  to increase the efficiency of the first media  202  during production), a lamination process, a pleating process, an ultrasonic bonding process, or the like. In such an arrangement, the fourth filter media portion  208  may be sealed to the first filter media  202  at an edge of the fourth filter media portion  208 . The fourth filter media portion  208  spans across a distance less than the filter media width across the width of the variable efficiency filter media  220 . The widths of the strips of the first, second, third, and fourth filter media portions  202 ,  204 ,  206 , and  208  can be the same or different. The variable efficiency filter media  220  of this embodiment has four separate zones of filtering efficiency: a first zone having only the first filter media portion  202 , a second zone having both the first filter media portion  202  and the second filter media portion  204 , a third zone having both the first filter media portion  202  and the third filter media portion  206 , and a fourth zone having both the first filter media portion  202  and the fourth filter media portion  208 . Each of the three zones has a different filtering efficiency. The overall efficiency of the variable efficiency filter media  220  can be tuned by adjusting the widths of each strip of filter media and by selecting appropriate filter media for each of the strips. 
     Any number of different filtering efficiency zones can be created over a base layer of the first filter media portion  202 . In some arrangements, a gradient of different filtering efficiency zones can be created over the base layer of the first filter media portion  202  by layering a high number of alternative filter media types onto the first filter media portion  202  to increase the filtering efficiency across the first filter media portion  202 . 
     The above described variable efficiency filter media  200 ,  210 , and  220  can be utilized in filter cartridges. For example, the variable efficiency filter media  200 ,  210 , and  220  can be pleated into a standard pleat pack that is used to produce a filter cartridge that does not require a parallel flow filter design to achieve the variable filtering efficiencies. Thus, the variable efficiency filter media  200 ,  210 , and  220  reduce filter cartridge design complexity and costs by eliminating the need for two cartridges of different filtering efficiencies and reducing the potential for fluid bypass and leaks. The filter cartridges can be of any shape, such as a cylindrical filter cartridge, a panel filter cartridge, or the like. Referring to  FIG. 3A , a perspective view of the variable efficiency filter media  200  pleated and formed into a cylindrical shape is shown. After pleating the variable efficiency filter media  200  and forming the cylindrical shape, the variable efficiency filter media  200  can be used in a filter cartridge.  FIG. 3B  shows a perspective view of an exemplary filter cartridge  300  that utilizes the pleated and cylindrically shaped variable efficiency filter media  200  shown in  FIG. 3A . The filter cartridge  300  includes a first endplate  302  and a second endplate  304 . The first endplate  302  is an open endplate, and the second endplate  304  is a closed endplate. The variable efficiency filter media  200  is positioned between the first endplate  302  and the second endplate  304 . Accordingly, the filter cartridge  300  has a varying filtering efficiency across an axial length of the filter cartridge  300 . 
     Similar filter cartridges can be constructed with variable efficiency filter media  210  and  220 . For example,  FIG. 3C  shows a perspective view of a filter cartridge  310  having the variable filtering efficiency media  210 . Filter cartridge  310  is similar in shape and construction to filter cartridge  300 . Further,  FIG. 3D  shows a perspective view of a filter cartridge  320  having the variable filtering efficiency media  220 . Filter cartridge  320  is similar in shape and construction to filter cartridges  300  and  310 . 
     Referring to  FIG. 4 , a perspective view of a filter cartridge  400  is shown according to an exemplary embodiment. The filter cartridge  400  is similar in shape and arrangement to the filter cartridge  300  of  FIG. 3B . The filter cartridge  400  includes a first endplate  402  and a second endplate  404 . The first endplate  402  is an open endplate, and the second endplate  404  is a closed endplate. A variable efficiency filter media  406  is positioned between the first endplate  402  and the second endplate  404 . The variable efficiency filter media  406  is comprised of a first filter media portion  408  and a second filter media portion  410 . The first filter media portion  408  has a first axial length D 1 . The first axial length D 1  spans the entire distance between the first endplate  402  and the second endplate  404 . The second filter media portion  410  is coupled to the first filter media portion  408  (e.g., via an air laid process, a wet laid process, a lamination process, a pleating process, an ultrasonic bonding process, etc.). The second filter media portion  410  may be sealed to the first filter media portion  408  at an edge of the second filter media portion  410 . Accordingly, in some arrangements, the first filter media portion  408  forms a structural support for the second filter media portion  410 . The second filter media portion has a second axial length D 2 . The second axial length D 2  extends from the second endplate  404  towards the first endplate  402 . However, the second axial length D 2  is shorter than the first axial length D 1  such that at least a portion of the first filter media portion  408  is not covered by the second filter media portion  410 . The zone of overlap between the first filter media portion  408  and the second filter media portion  410  creates a first zone of high efficiency media, while the zone where only the first filter media portion  408  exists creates a second zone of standard efficiency media. In some arrangements, D 1  is 221 mm and D 2  is 91 mm. In such arrangements, the effective area ratio of the variable efficiency filter media  406  is 59% standard efficiency and 41% high efficiency. 
     The above-described filter cartridges utilizing the variable efficiency filter medias provide for a cost-effective filter cartridge by eliminating the need for two cartridges in a parallel flow or shunt filter design (e.g., as described above with respect to  FIG. 1 ). The variable efficiency filter media has improved filter life, lower restriction, and increased capacity for contaminant while maintaining efficiency. 
     Referring to  FIG. 5 , a system diagram of a variable efficiency filter media manufacturing system  500  is shown according to an exemplary embodiment. The system  500  is a small air laid (i.e., melt blowing) machine used to create a variable efficiency filter media  502 . A first roll  504  of base material  506  (e.g., scrim) is fed into the system  500  (e.g., via an electric motor that rotates the first roll  504 ). At least one strip of high efficiency filter media  508  is laid on top of the base material  506 . The high efficiency filter media  508  may, for example, be similar to the second, third, or fourth filter media portions  204 ,  206 , or  208  that are described above with respect to  FIGS. 2A through 2C . The high efficiency filter media  508  may be unwound from supply rolls  509  at the desired positions along the base material  504 . The supply rolls  509  are adjustable to vary the characteristics of the variable efficiency filter media  502 . The layered base material  506  and high efficiency filter media  508  is then passed over a forming drum  510 . At the forming drum  510 , a spray of fiber standard filter media  512  is sprayed out of a melt blowing device  514  (e.g., a sprayer) and onto the base material  506  and the high efficiency filter media  508 . The spray of fiber standard filter media  512  solidifies in place, which secures the standard filter media  512  and the high efficiency filter media  508  to the base material  504 . The combined base material  504 , high efficiency filter media  508 , and standard filter media  512  form the variable efficiency filter media  502 . The formed variable efficiency filter media  502  is rolled onto a storage roll  516 , where the variable efficiency filter media  502  is stored for further processing (e.g., shaping the variable efficiency filter media  502  for use in a filter cartridge). In some arrangements, the base material  506  is separated from the combined standard efficiency filter media  512  and the high efficiency filter media  508  prior to storage on the storage roll  516 . In some arrangements, the system  500  can provide continuous or discontinuous (with respect to the axial length, width, or circumferential length of the variable efficiency filter media  502 ) regions of variable efficiency filter media  502  (e.g., by stopping or starting the placement of the high efficiency filter media  508 ). 
       FIG. 6  shows a system diagram of a variable efficiency filter media manufacturing system  600  according to an exemplary embodiment. System  600  is similar to system  500 . The primary difference between systems  500  and  600  is that system  600  layers the high efficiency filter media  508  onto the base material  506  in a different manner than system  500 . Specifically, system  600  sprays the high efficiency filter media  508  out of at least one melt blowing device  602  (e.g., a sprayer) onto the base material  506 . The melt blowing devices  602  are repositionable such that the high efficiency filter media  508  can be sprayed from the melt blowing devices  602  at the desired positions along the base material  504 . The melt blowing devices  602  can provide different thicknesses and widths of the high efficiency filter media  508  such that the zones and efficiencies of the high efficiency filter media  508  can also be varied. In some arrangements, the system  600  can provide continuous or discontinuous (with respect to the axial width, linear length, width, or circumferential length of the variable efficiency filter media  502 ) regions of variable efficiency filter media  502  (e.g., by stopping or starting the spraying of the high efficiency filter media  508 ). 
     Continuing on to  FIG. 7 , a system diagram of a co-pleating system  700  is shown according to an exemplary embodiment. The co-pleating system  700  first layers a wire screen  702  fed from a roll  704  against the variable efficiency filter media  502  fed from the storage roll  516  to form screened filter media  706 . After forming the screened filter media  706 , the screened filter media  706  is optionally cut to the appropriate width by a series of rolling cutters  708 . The sized screened filter media  706  is then pleated by a pleating machine  710  to form a pleated variable efficiency filter media  712  (e.g., as used in the cylindrical filter media  200  of  FIG. 3A ). 
     In the above-described methods of producing the variable efficiency filter media, certain production parameters can be adjusted to affect the filtering efficiency of the variable efficiency filter media. For example, during a polymeric air laid process of making a particular filter media, differing material viscosities can be used to obtain differing fiber diameters across the web of a dual supply of polymer. Additionally, different die geometry can be used with an air laid process (e.g., alternative hole diameters across the die and the web). Further, the die geometry can be altered to provide an air gap alteration of 1.6 mm→1.0 mm (e.g., in wave form or as a right angle/squared off manner. The die geometry can be further altered to add laval nozzles in areas across the air lips of the air laid process. Further, air flow can be increased or decreased (e.g., increasing or decreasing the air flow volume, accelerating or decelerating the air flow, etc.) during the air laid process. Still further, high compression and/or calendaring of areas or zones of the filter media in the cross direction can be done to alter the filtering efficiency of the variable efficiency filter media. 
     Referring to  FIG. 8 , a system diagram of a pleated variable efficiency filter media manufacturing system  800  is shown according to an exemplary embodiment. The system  800  receives wire screen  802  from a wire screen roll  804 . At least one strip of high efficiency filter media  806  is laid on top of the wire screen  802 . The high efficiency filter media  806  may, for example, be similar to the second, third, or fourth filter media portions  204 ,  206 , or  208  that are described above with respect to  FIGS. 2A through 2C . The high efficiency filter media  806  may be unwound from supply rolls  808  at the desired positions along the wire screen  802 . The supply rolls  808  are adjustable to vary the characteristics of the final pleated variable efficiency filter media  810 . A standard filter media  810  is then layered on top of the wire screen  802  and the high efficiency filter media  806 . The standard filter media  810  may be unwound from a standard filter media roll  812 . In some arrangements, the standard filter media is a non-woven filter media. When layered, the high efficiency filter media is positioned between the wire screen  802  and the standard filter media  810  thereby forming a screened filter media  814 . The screened filter media  814  has a variable filtering efficiency. After forming the screened filter media  814 , the screened filter media  814  is optionally cut to the appropriate width by a series of rolling cutters  816 . The sized screened filter media  814  is then pleated by a pleating machine  818  to form the pleated variable efficiency filter media  820  (e.g., as used in the cylindrical filter media  200  of  FIG. 3A ). 
     Variable efficiency filter media can also be produced from a single type of filter media (e.g., standard filter media) by folding the filter media over itself or by overlapping multiple layers of the filter media. For example, as shown in  FIG. 9 , a single sheet of standard filter media  902  can be folded over itself to create a first zone  904  of standard filtering efficiency and a second zone  906  of higher filtering efficiency. The first zone  904  has a first width  908 , and the second zone  906  has a second width  910 . The first width  908  and the second width  910  total the filter media width. The first width  908  and the second width  910  are adjusted by placement of the fold line  912  along the width  914  of the unfolded sheet of standard filter media  902 . The fold line  912  can be oriented in different manners such that the sheet of standard filter media  902  can be folded over on one end, two ends, or along the middle of the filter media width (i.e., as shown in  FIG. 9 ). In some arrangements, the folded over portion of the standard filter media  902  can be bonded to itself to maintain the fold. As another example, as shown in  FIG. 10 , two sheets of standard filter media  1002  and  1004  can be overlapped to form an overlap zone  1006  of higher filtering efficiency than the standard filter media  1002  and  1004 . In an alternative arrangement, two sheets of different filter media are overlapped to create three different zones of filtering efficiency. In some arrangements, the two sheets of standard filter media  1002  and  1004  are bonded at the overlap zone  1006 . The combined width  1008  is less than the combined individual widths  1010  and  1012  of the two sheets of standard filter media  1002  and  1004 . The individual widths  1010  and  1012  may be the same or different. In some arrangements, the individual widths  1010  and  1012  are 8.7 inches and the combined width  1008  is also 8.7 inches. 
     The above-described variable efficiency media provides an axial variation of filtering efficiency across the filter media width in a single media. The single media may incorporate multiple types of media into the single media to provide zones or areas of an increased overall efficiency performance. The increased efficiency depends on the effective area ratios of the filter media (e.g., the ratio of standard filter media to high efficiency filter media), the efficiency of the standard filter media, and the efficiencies of any added filter material. For example, Table 1 shows different efficiency ratios and demonstrates improvements in small particulate removal as the area of the higher efficiency media is increased. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Option #1 
                 Option #2 
                 Option #3 
                 Option #4 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Full flow 
                 flow rate (lpm) 
                 105 
                 63.1 
                 43.8 
                 22.2 
               
               
                 Bypass 
                 flow rate (lpm) 
                 0 
                 41.9 
                 61.2 
                 82.8 
               
               
                 Full flow 
                 % flow rate 
                 100 
                 60.1 
                 41.7 
                 21.1 
               
               
                 Bypass 
                 % flow rate 
                 0 
                 39.9 
                 58.3 
                 78.9 
               
            
           
           
               
               
               
               
               
            
               
                 Equilibrium Sump Part Counts &gt; 5 μm 
                 1064 
                 657 
                 558 
                 474 
               
               
                 Equilibrium SUMP ISO Code 
                 17 
                 17 
                 16 
                 16 
               
               
                 Sump count percent reduction 
                   
                 38.3 
                 47.6 
                 55.5 
               
               
                   
               
            
           
         
       
     
     The improved efficiency is also shown in graph  1100  of  FIG. 11 . Table 1 and graph  1100  demonstrate the efficiency improvements comparing 100% standard media to increasing percentages of high efficiency media. 
     Referring to  FIG. 12 , a graph  1200  showing changes of filtering efficiency over time for various filter media are shown. As shown in graph  1200 , the variable efficiency filter media arrangements offer improved filtering efficiency percentages over the standard filter media with minimal losses in filter media life. Referring to  FIG. 13 , a graph  1300  of pressure drop (in kPa) over time for various filter media are shown. As shown in graph  1300 , the variable efficiency filter media arrangements cause a slightly larger, but minimal, pressure drop over time than the standard filter media. 
     As described above, the variable efficiency media may be formed by ultrasonically bonding different layers of filter media to each other. In certain arrangements where a layer of media does not extend the full length of a filter cartridge (i.e., does not span the entire distance between two endcaps), the ultrasonic bonding of the adjacent layers of filter media can provide additional structural support to the filter cartridge. In some arrangements, the ultrasonic bonding may occur at an edge of the second filter media through a continuous weld. In such arrangements, the continuous weld may form a seal between the first filter media and the second filter media. One such arrangement is described below with respect to  FIG. 14 . 
       FIG. 14  shows a cross-sectional view of a filter cartridge  1400  having a variable efficiency filter media. The variable efficiency filter media includes first filter media  1402  having a first filtering efficiency. The first filter media  1402  extends the full distance between the a first endcap  1404  and a second endcap  1406 . The first and second endcaps  1404  and  1406  may be formed of a plastic material, epoxy, urethane, or the like. In some arrangements, the first filter media  1402  is sealed to the first and second endcaps  1404  and  1406  through a plastisol material, urethane, epoxy or the like. In some arrangements, the first filter media  1402  is thermally embedded or adhered to the first and second endcaps  1404  and  1406  before the first and second endcaps  1404  and  1406  are fully cured (e.g., when the first and second endcaps  1404  and  1406  are semi-molten). The variable efficiency filter media includes second filter media  1408  having a second filtering efficiency. In some arrangements, the second filtering efficiency is different than the first filtering efficiency. In other arrangements, the second filtering efficiency is the same as the first filtering efficiency. In some arrangements, the second filter media  1408  is placed downstream of the first filter media  1402  in a fluid flow direction through the variable efficiency filter media. 
     As shown in  FIG. 14 , the second filter media  1408  extends from the first endcap  1404  towards the second endcap  1406 . However, the second filter media  1408  does not extend the entire distance between the first endcap  1404  and the second endcap  1406 . Accordingly, the second filter media  1408  terminates before reaching the second endcap  1406 . The end of the second filter media  1408  opposite the first endcap  1404  is secured to the first filter media  1402  via an ultrasonic weld  1410 . Additionally, the inclusion of the ultrasonic weld  1410  provides additional structural integrity to the variable efficiency filter media thereby eliminating the need for a central support tube (or additional central support tube) in the filter cartridge  1400 . The ultrasonic bond formed by the ultrasonic weld  1410  allows for a differential pressure between the upstream and downstream side of the filter cartridge  1400 . The ultrasonic weld  1410  may be produced by passing the filter media  1400  through an ultrasonic welding machine that utilizes an ultrasonic anvil drum. In some arrangements, the ultrasonic anvil drum can incorporate a pattern or design into the layered variable efficiency filter media thereby making the variable efficiency filter media easier for technicians to visually distinguish the two sides from one another. 
     The above-described variable efficiency media combines multiple media performances, high and standard efficiency, into a single, variable efficiency filter media. The variable efficiency media may include multiple variations (e.g., arrangements of standard efficiency filter media and the high efficiency filter media) or gradient structure of increasingly higher efficiency media into one composite media. The variable efficiency filter media can be formed by methods of intentional altering media formulation or formation to alter media physical characteristics (e.g., pore size, fiber diameter, etc.) or by simple insertion of higher efficiency layers into the standard efficiency filter media, which alters the overall media performance in the cross direction and/or in the linear direction of the media web. This alternation achieves a targeted overall efficiency performance when the media is pleated into a filtration element. Benefits of the variable efficiency media over standard efficiency media may include improved filter life, lower overall filter restriction, and increased capacity for contaminant while maintaining efficiency. Further, the described variable efficiency media provide an improved way to manage the flow balance over existing parallel flow elements. The variable efficiency media further allows for simplified filter cartridge design where the ratio of high and standard efficiency media width can be easily changed. The easily changeable ratio allows for easy determination and predictability of the flow balance through each media in the variable efficiency media. This design flexibility allows for filter performance changes without altering or changing hardware. 
     The above-described variable efficiency media may be used in a variety of different types of filtration systems, such as fuel filtration systems, lubricant filtration systems, hydraulic fluid filtration systems, water filtration systems, and the like. For example, the lubrication filtration systems typically have to filter viscous liquids, which can present filtration issues. At low temperature, lube oil viscosity is high and the oil needs to have large pore sizes in the filter media to flow through. However, the large pore size of the media required will have low particle removal efficiency, which can result in excess engine component wear. Use of the above-described variable efficiency media permits viscous lubricant flow through the lubricant system. Additionally, as the lube heats up and becomes less viscous, the lube passes through the higher efficiency portions of the variable efficiency filter media, which improves the total system filtration efficiency. 
     In addition to the above described variable efficiency media that layers various efficiency media on top of one another, a similar effect may be achieved by intentionally altering a media formulation or formation to alter media physical characteristics (e.g., pore size, fiber diameter, etc.) across a length of the media. 
     It should be noted that any use of the term “exemplary” herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” “overlaid,” “underlaid,” “interlaid,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. Specifically, media described as overlaid can be underlain, for example. Alternatively, the orientation of media layers in manufacturing the composite can be reversed in order from the final element orientation. A combination of overlaid and underlain media—with three or more media—may also be implemented. 
     It is important to note that the construction and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Additionally, features from particular embodiments may be combined with features from other embodiments as would be understood by one of ordinary skill in the art. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.