Patent Publication Number: US-2021189926-A1

Title: Anti-rotation features for crankcase ventilation filters

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Application No. 62/675,978, filed May 24, 2018 and the contents of which are incorporated herein by references in the entirety and for all purposes. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to filters for use with internal combustion engine systems. 
     BACKGROUND 
     During operation of an internal combustion engine, a fraction of combustion gases can flow out of the combustion cylinder and into the crankcase of the engine. These gases are often called “blowby” gases. The blowby gases include a mixture of aerosols, oils, and air. If vented directly to the ambient, the aerosols contained in the blowby gases can harm the environment. Accordingly, the blowby gases are often routed out of the crankcase via a crankcase ventilation system. The crankcase ventilation system may pass the blowby gases through a coalescer (i.e., a coalescing filter element) to remove a majority of the aerosols and oils contained in the blowby gases. The filtered blowby gases (“clean” gases) are then either vented to the ambient (in open crankcase ventilation systems) or routed back to the air intake for the internal combustion engine for further combustion (in closed crankcase ventilation systems). 
     Some crankcase ventilation systems utilize rotating crankcase ventilation filter elements, for example, rotating coalescer elements that increase the filter efficiency of crankcase ventilation systems by rotating the coalescer element during filtering. In rotating coalescer elements, the contaminants (e.g., oil droplets suspended and transported by blowby gases) are separated at least in part by centrifugal separation techniques. Additionally, the rotation of the coalescer element can create a pumping effect, which reduces the pressure drop through the crankcase ventilation system. 
     In some embodiments, the rotating crankcase ventilation filter element may include a corrugated and/or wound axial filter media layers, for example, a filter media layer wound into a roll. When used in rotating filters (e.g., as a filter media in a rotating coalescer filter element) the layers of filter media may become lose when the filter element is spinning, especially at elevated temperature which may cause a mass shift and therefore whirling. The mass shift may unbalance the filter element, which can damage bearings and reduce the life of crankcase ventilation filters. 
     SUMMARY 
     Embodiments described herein relate generally to systems and methods for securing a plurality of filter media layers of a filter media within a housing and in particular, to top and bottom end caps positioned on axial ends of the filter media, at least one of which includes indenting features configured to indent and interlock plurality of filter media layers at the indenting points. 
     In a set of embodiments, a rotating crankcase ventilation filter element comprises a filter media comprising a plurality of filter media layers. A first end cap is positioned on a filter media first end of the filter media. The first end cap comprises a first end cap main body, and a first plurality of indenting features positioned on the first end cap main body proximate the filter media first end. The first plurality of indenting features contact and indent corresponding segments of the filter media first end causing the plurality of filter media layers to interlock at the corresponding segments, the interlocking preventing movement of the plurality of filter media layers relative to each other. 
     In another set of embodiments, an end cap assembly for a filter element comprises a first end cap configured to be positioned on a filter media first end of a filter media that comprises a plurality of filter media layers. The first end cap comprises a first end cap main body, and a first plurality of indenting features positioned on the first end cap main body. The first plurality of indenting features are configured to contact and indent corresponding segments of the filter media first end so as to cause the plurality of filter media layers to interlock at the corresponding segments, the interlocking preventing movement of the plurality of filter media layers relative to each other. A second end cap is configured to be positioned on a filter media second end of the filter media opposite the filter media first end. 
     In another set of embodiments, a method comprises providing a wound filter media comprising a plurality of filter media layers. A filter media first end of the filter media is positioned on a first end cap. The first end cap comprises a first end cap main body, and a first plurality of indenting features are positioned on the first end cap main body. The first plurality of indenting features are configured to contact and indent corresponding segments of the filter media first end, causing the plurality of filter media layers to interlock at the corresponding segments. The interlocking prevents movement of the plurality of filter media layers relative to each other. A filter media second end of the filter media is positioned opposite the filter media first end on a second end cap. 
     It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several implementations in accordance with the disclosure and are therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings. 
         FIG. 1A  is a cross-sectional view of a crankcase ventilation system, according to an embodiment. 
         FIG. 1B  is a schematic illustration of a filter element, according to an embodiment. 
         FIG. 2  is a top perspective view of a first end cap and a second end cap of a filter element coupled together, according to another embodiment. 
         FIG. 3  is a side view of the filter element of  FIG. 2 . 
         FIG. 4  is a bottom view of a first end cap of the filter element of  FIG. 2 , according to an embodiment. 
         FIG. 5  is a side cross-section view of a portion of the first end cap of  FIG. 4 . 
         FIG. 6  is another side cross-section view of the first end cap of  FIG. 4 . 
         FIG. 7  is another side cross-section view of a portion of the first end cap of  FIG. 4  as indicated by the arrow A in  FIG. 5 . 
         FIG. 8  is a side cross-section of a portion of the first end cap of  FIG. 4  as indicated by the arrow B in  FIG. 7 . 
         FIG. 9  is a top perspective view of a second end cap of the filter element of  FIG. 2 , according to an embodiment. 
         FIG. 10  is a side view of the second end cap shown in  FIG. 9 . 
         FIG. 11  is a top view the second end cap of  FIG. 9 . 
         FIG. 12  is a side cross-section view of the second end cap of  FIG. 9  taken along the line A-A shown in  FIG. 11 . 
         FIG. 13  is a side cross-section view of a portion of the second end cap of  FIG. 9  shown in  FIG. 12  as indicated by the arrow B. 
         FIG. 14  is another side cross-section view of a portion of the second end cap of  FIG. 9  indicated by the arrow C in  FIG. 13 . 
         FIG. 15  is a top view of the filter element of  FIG. 2  with the first end cap removed to show indentations formed by indenting features of the first end cap on a plurality of filter media layers of a filter media disposed in the housing. 
         FIG. 16  is a schematic flow diagram of a method for securing a plurality of filter media layers of a filter media within a housing extending from the first end cap. 
     
    
    
     Reference is made to the accompanying drawings throughout the following detailed description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative implementations described in the detailed description, drawings, and claims are not meant to be limiting. Other implementations may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure. 
     DETAILED DESCRIPTION 
     Embodiments described herein relate generally to systems and methods for securing a plurality of filter media layers of a filter media within a housing and in particular, to top and bottom end caps positioned on axial ends of the filter media, at least one of which includes indenting features configured to indent and interlock plurality of filter media layers at the indenting points. 
     Embodiments of the rotating crankcase ventilation filter elements described herein may provide benefits including, for example: (1) providing indenting features in a first and/or second end cap of the filter element which interlock a plurality of filter media layers of a filter media of the filter element so as to prevent relative movement of the plurality of filter media layers due to rotation of the filter element; (2) preventing unwinding of the plurality of filter media layers which can reduce filtering efficiency of the filter media; (3) preventing mass shift and maintaining rotational balance of the filter media, therefore preventing damage to bearings of a motor or turbine configured to rotate the filter element; and (4) reducing maintenance costs and increasing life of the filter element as well as rotating components used to rotate the filter element. 
     Referring to  FIG. 1A , a cross-sectional view of a crankcase ventilation system  10  is shown according to an example embodiment. The crankcase ventilation system  10  is used to describe the basic operations of a system that includes a rotating crankcase ventilation filter element  16  (e.g., a rotating coalescer element) driven by a pressurized fluid or a motor. The crankcase ventilation system  10  generally processes blowby gases received from an internal combustion engine crankcase to remove aerosols, oils, and other particulate contained in the crankcase blowby gases. The crankcase ventilation system  10  generally includes a housing  12  having an inlet  14  that receives crankcase blowby gases to be filtered (e.g., from a crankcase of an internal combustion engine), a central compartment having a rotating crankcase ventilation filter element  16 , for example, a rotating coalescer element installed therein, and an outlet  18  that provides filtered blowby gases to the internal combustion engine (in a closed crankcase ventilation system) or to the ambient (in an open crankcase ventilation system). 
     During operation of the crankcase ventilation system  10 , blowby gases enter the housing  12  through the inlet  14 . The blowby gases are directed to the central compartment where the blowby gases flow through the filter element  16  in an inside-out manner. In an alternate arrangement, the crankcase ventilation system  10  can be configured to have an outside-in flow arrangement. The filter element  16  may be coupled to a central shaft  50  that transfers rotation to the filter element  16 . The central shaft  50  may be rotationally driven by a turbine  22  that is rotated by a jet of oil generated by an oil pump  24 . The turbine  22  may be an impulse turbine. As the filter element  16  rotates, the filter element  16  (e.g., a rotating coalescer element) separates oil, aerosols, and other contaminants contained in the blowby gases. The separated contaminants drain from the housing  12  through a drain  26  and return to the engine crankcase sump  28 . The filter element  16  may include a first endcap  20 , a second endcap  42 , and a filter media  40  (e.g., a separating device). In various embodiments, the filter media  40  may comprise a corrugated and wound filter media configured for axial flow such as the filter element  100 ,  200  or  300  described in further detail below. For example, the filter media  40  may include a plurality of filter media layers formed by winding or rolling a single layer of filter media into a cylindrical shape. 
       FIG. 1B  is a schematic illustration of a filter element  100  that may be used as the filter element in the crankcase ventilation system  10 , according to an embodiment. The filter element  100  may be used to filter a fluid e.g., a gas (e.g., air, fuel, air-fuel mixture, blowby gases) or any other fluids used in internal combustion engines. The filter element  100  comprises a housing  102  and a filter media  110  disposed within the housing. In particular embodiments, the filter element  100  comprises a rotating crankcase ventilation filter element. In such embodiments, the filter element  100  may be configured to filter crankcase blowby gases received from the internal combustion engine crankcase, for example, to remove aerosols, oils, and other particulate contained in the crankcase blowby gases. In various embodiments, the filter element  100  may be mounted or coupled to the central shaft  50 . The central shaft  50  may be operatively coupled to a motor (e.g., a DC motor) or turbine and configured to rotate the filter element  100 , for example, to facilitate centrifugal separation of aerosols, oils, water, etc. from the blowby gases. 
     The housing  102  defines an internal volume  103  within which the filter media  110  is disposed. The housing  102  may be formed from a strong and rigid material, for example plastics (e.g., polypropylene, high density polyethylene, polyvinyl chloride, etc.), metals (e.g., aluminum, stainless steel, etc.), polymers (e.g., reinforced rubber, silicone) or any other suitable material. In some embodiments, the housing  102  may include a cover  104 . The cover  104  may be removed to allow insertion or removal of the filter media  110  within the housing  102 . In particular embodiments, an end cap assembly comprising a first end cap  120  positioned at a first end of the filter media  110  may form base and sidewalls of the housing  102 , and the second end cap  130  positioned at a second end of the filter media  110  opposite the first end may form the cover  104 . 
     The filter media  110  is positioned along a longitudinal axis A L  of the filter element  100 . In some embodiments, the filter media  110  may comprise a corrugated and wound filter media configured for axial flow. For example, the filter media  110  may include a plurality of filter media layers formed by winding or rolling a single layer of filter media  110  into a cylindrical shape. In various embodiments, the filter media  110  may be configured for axial flow. For example, the corrugations of the plurality of filter media layers may define axial flow channels therebetween so as to allow axial flow of the gas through the axial flow channels. 
     As previously described, the filter element  100  may include a rotating crankcase ventilation filter element mounted on the central shaft  50  configured to rotate the filter element. The rotation may cause oil, particles or other contaminants included in the fluid (e.g., blowby gases) flowing through the channels formed between the plurality of layers of the filter media  110  to coalesce. The coalesced droplets are then removed from the filter element. Rotation of the filter element  100  may cause the filter media  110  to unwind. This may decrease filtering efficiency of the filter media  110  and may also cause a mass shift of the filter media  110  (e.g., causing a center of gravity or axis of the filter media  110  to shift). The mass unbalance may cause whirling of the central shaft  50  which may damage bearings on which the central shaft  50  is mounted and/or a turbine (e.g., the turbine  22 ) driving the central shaft  50 . 
     The filter element  100  includes the first end cap  120  positioned on a filter media first end  111  and the second end cap  130  positioned on a filter media second end  113  of the filter media  110 , at least one of which includes indenting features structured to indent and interlock the plurality of filter media layers of the filter media  110  at certain segments so as to prevent movement of the plurality of filter media layers relative to each other. 
     Expanding further, the first end cap  120  comprises a first end cap main body  122  formed from any suitable material, for example, plastics, polymers, metals, etc. The first end cap main body  122  may comprise a disc having a cross-section corresponding to or larger than an outer cross-section of the filter media  110 . A first plurality of indenting features  124  are positioned on the first end cap main body  122  proximate to the filter media first end  111 . For example, the first plurality of indenting features  124  may include ribs or pillars extending from the first end cap main body  122  towards the filter media  110 . An edge of each of the first plurality of indenting features  124  proximate to the filter media first end  111  may be flat, rounded or may have a knife edge defined on an axial edge thereof. 
     The first plurality of indenting features  124  are configured to contact and indent corresponding segments of the filter media  110  at the filter media first end  111 , causing the plurality of filter media layers to interlock at the corresponding segments of the filter media first end  111 . The interlocking prevents movement of the plurality of filter media layers relative to each other. For example, the first end cap  120  may be positioned on the filter media first end  111  with sufficient force so as to cause the first plurality of indenting features  124  to indent (e.g., crimp) the plurality of the filter media layers with each other at the indented segments. In this manner, the plurality of filter media layers become interlocked which prevents movement of the plurality of filter media layers relative to each other when the filter element  100  is rotated. 
     In particular embodiments, the first end cap  120  may comprise a plurality of flow vanes extending axially from the first end cap main body  122  towards the filter media  110 . The plurality of flow vanes may include one or more inlets configured to allow fluid to enter radially relative to the filter media  110  into radial flow channels defined between the plurality of flow vanes. Each of the plurality of flow vanes may be positioned perpendicular to the plurality of filter media layers of the filter media  110  such that the plurality of radial flow channels defined therebetween are in fluid communication with the flow paths defined between one or more of the plurality of filter media layers. 
     In such embodiments, the first plurality of indenting features  124  may comprise a knife edge defined on an axial edge of each of a set of the plurality of flow vanes. For example, a set of the plurality of flow vanes positioned at predetermined locations on the first end cap main body  122  may each have a knife edge defined at an axial edge thereof. In some embodiments, the first plurality of indenting features  124  may be positioned axisymmetrically on the first end cap main body  122  (i.e., positioned symmetrically around the longitudinal axis A L ). 
     For example, each of the set of the plurality of flow vanes may be positioned in a radial array such that an angle between adjacent flow vanes included in the set of the plurality of flow vanes may be in range of 10 degrees to 180 degrees. In some embodiments, the set of the plurality of flow vanes may be located at the four poles of first end cap main body  122  such that adjacent flow vanes of the set of the plurality of flow vanes have an angular pitch of 90 degrees. In other embodiments, the set of the plurality of flow vanes may include three vanes having an angular pitch of 120 degrees. 
     In some embodiments, the first end cap  120  may also comprise a first central pillar  126  extending axially from the first end cap main body  122  at least a portion of a length of a central channel  112  defined by the filter media  110 . The first central pillar  126  may include engaging features (e.g., a snap fit mechanism) configured to engage corresponding second engaging features defined on a corresponding second central pillar  136  of the second end cap  130 , as described in further detail herein. One or more first support pillars may be positioned around the first central pillar  126 , and may also extend from the first end cap main body  122  into the central channel  112 . The one or more first support pillars may also include engaging features (e.g., a snap fit mechanism) configured to engage corresponding engaging features defined on second support pillars of the second end cap  130 . First spacer ribs  128  may extend radially outwards from the first central pillar  126 . The first spacer ribs  128  may have a length corresponding to a cross-section of the central channel  112  (e.g., a radius thereof). For example, the filter media  110  may be wound around the first spacer ribs  128  such that the first spacer ribs  128  define the cross-section (e.g., diameter) of the central channel  112 . 
     The second end cap  130  comprises a second end cap main body  132 . A second plurality of indenting features  134  are positioned on the second end cap main body  132  proximate to the filter media second end  113  opposite the filter media first end  111 . The second plurality of indenting features  134  are configured to contact and indent corresponding segments of the filter media second end  113  causing the plurality of filter media layers to also interlock at the corresponding segments of the filter media  110  at the filter media second end  113 , as described with respect to the first end cap  120 . In various embodiments, the second end cap main body  132  may define a ring shaped structure defining an axial outlet configured to allow filtered fluid (e.g., filtered blowby gases) to exit the filter element  100 . 
     In some embodiments, the second end cap  130  may comprise a plurality of ribs extending axially from the second end cap main body  132  towards the filter media  110 . The second plurality of indenting features  134  may also comprise a knife edge defined on an axial edge of each of a set of the plurality of ribs. In some embodiments, the second plurality of indenting features  134  may be positioned axisymmetrically on the second end cap main body  132 , for example as described with respect to the first end cap  120 . The set of the plurality of ribs may be equal or different in number to the set of plurality of flow vanes, and may be axially aligned or offset from the set of the plurality of flow vanes of the first end cap  120 . 
     In some embodiments, each of the plurality of ribs may also include flow vanes defining outlet flow channel therebetween. Filtered fluid (e.g., filtered blowby gases) flowing axially through the flow paths between the plurality of filter media layers may flow into the outlet flow channels and may be redirected to flow in a radial direction towards the axial outlet defined in the second end cap main body  132  and out of the filter element  100 . 
     In some embodiments, the second end cap  130  may also include the second central pillar  136  and one or more second spacer ribs  138  extending from the second central pillar  136  towards a rim of the axial outlet. The second central pillar  136  is axially aligned with the first central pillar  126  and extends into the central channel  112  towards the first central pillar  126 . The second spacer ribs  138  may be coupled to the second end cap main body  132  such that the second central pillar  136  is suspended over the axial outlet, and a plurality of gaps between adjacent second spacer ribs  138  fluidly couple flow channels defined between the plurality of ribs  128  to the axial outlet. One or more second support pillars may also be positioned around the second central pillar  136  and may also include engaging features (e.g., a snap-fit or friction fit features) configured to engage corresponding engaging features provided on the first supporting pillars. 
       FIG. 2  is a top perspective view and  FIG. 3  is a side view of a filter element  200  that may be used as the filter element in the crankcase ventilation system  10  or any other crank case ventilation system, according to an embodiment. The filter element  200  may be used to filter a fluid e.g., blowby gases or any other fluid used in internal combustion engines. The filter element  200  comprises a housing  202  defining an internal volume within which a wound filter media  210  shown in  FIG. 15 , or any other filter media (e.g., the filter media  110 ) may be disposed. The filter element  200  comprises an end cap assembly including a first end cap  220  which forms the housing  202 , and a second end cap  230  coupled to the first end cap  220 . 
     Referring to  FIGS. 3-8  which show various views of the first end cap  220 , the first end cap  220  comprises a first end cap main body  222  formed from any suitable material, for example, plastics, polymers, metals, etc. The first end cap main body  222  comprises a circular disc having a cross-section corresponding to an outer cross-section of the filter media  210 . In other embodiments, the first end cap main body  222  may have any suitable shape or cross-section, for example, square, rectangular, elliptical, race track shape, asymmetrical or any other suitable shape (e.g., corresponding to an outer cross-section of the filter media which may be positioned in the housing  202 ). 
     The first end cap  220  comprises a plurality of flow vanes  223  extending axially from the first end cap main body  222  towards the internal volume defined by the housing  202  so as to define a plurality of radial flow channels  225 . The plurality of flow vanes  223  include inlets  221  configured to allow fluid to enter radially relative to the filter media  110  into the radial flow channels  225  defined between adjacent flow vanes  223 . Each of the plurality of flow vanes  223  may be positioned perpendicular to a plurality of filter media layers  214  of the filter media  210  such that the flow channels defined therebetween are in fluid communication with the flow paths defined between one or more of the plurality of filter media layers  214 . 
     The housing  202  may be positioned over the plurality of flow vanes  223  and coupled thereto such that a plurality of inlets  221  are formed between the first end cap main body  222  and a housing first end proximate to the first end cap main body  222 , with sidewalls thereof formed by adjacent flow vanes  223 . In some embodiments, the housing  202  may be monolithically formed with the first end cap main body  222  such that the first end cap  220  includes the housing  202 . 
     The first end cap  220  comprises a first plurality of indenting features  224  configured to contact and indent corresponding segments at a filter media first end of the filter media  210  so as to interlock the plurality of filter media layers  214  at the corresponding segments of the filter media  210 , the interlocking preventing movement of the plurality of filter media layers  214  relative to each other, as previously described herein. As shown in  FIGS. 4-8 , a set  223   a  of the plurality of flow vanes  223  positioned axisymmetrically on the first end cap main body  222  each have a knife edge defined at an axial edge thereof, the knife edge forming the corresponding indenting feature  224 . Specifically, the set  223   a  of the plurality of flow vanes  223  may be located at the four poles of the first end cap main body  222  such that adjacent flow vanes  223  of the set  223   a  of the plurality of flow vanes  223  have an angular pitch of 90 degrees. In other embodiments, fewer or more of the plurality of flow vanes  223  may define the indenting feature  224 , or the set  223   a  of the plurality of flow vanes  223  may be located at any other position or at any angular pitch. For example, each of the set  223   a  of the plurality of flow vanes  223  may be positioned in a radial array such that an angle between adjacent flow vanes  223  included in the set  223   a  may be in a range of 10 degrees to 180 degrees. In other embodiments, the set  223   a  of the plurality of flow vanes  223  may include three flow vanes having an angular pitch of 120 degrees. 
     The first end cap  220  may also comprise a first central pillar  226  extending axially from the first end cap main body  222  having a length which may be smaller than a height of the housing  202  so as to extend at least a portion of a length of a central channel  212  defined by a filter media  210  which may be positioned in the housing  202 . The first central pillar  226  may include engaging features (e.g., a snap fit mechanism) configured to engage corresponding second engaging features defined on a corresponding second central pillar  236  of the second end cap  230 , as described in further detail herein. For example, as best shown in  FIG. 5 , a protrusion  227  extends from an axial end of the first central pillar  226  distal from the first end cap main body  222 . The protrusion  227  may be configured to be inserted into a mating receptacle  237  defined in a second central pillar of the second end cap  230 , for example, to facilitate aligning of the first end cap  220  with the second end cap  230  and/or snap-fit or friction fit the first end cap  220  to the second end cap  230 . 
     A plurality of first support pillars  229  are positioned around the first central pillar  226 , and may also extend from the first end cap main body  222  into the central channel  212 . Each of plurality of first support pillars  229  may also include engaging features (e.g., a snap fit mechanism) configured to engage corresponding engaging features defined on second support pillars  239  of the second end cap  230 . For example, and as shown in  FIG. 4 , each of the plurality of first support pillars  229  may define apertures  229   a  configured to receive corresponding protrusions  239   a  defined on the second support pillars  239 . In this manner, the plurality of first support pillars  229  and the plurality of second support pillars  239  may interlock so as to prevent rotation of the first end cap  220  and the second end cap  230  relative to each other. 
     First spacer ribs  228  may extend radially outwards from the first central pillar  226 . The first spacer ribs  228  may have a length corresponding to a cross-section of the central channel  212  (e.g., a radius thereof). For example, an outer edge of each of the plurality of first spacer ribs  228  distal from the first central pillar  226  may correspond to an inner periphery of the filter media  210  positioned within the housing  202 . The plurality of filter media layers  214  may be wound around the first spacer ribs  228 , or wound outside of the housing  202  to formed the cylindrical filter media  210  and then positioned around the first spacer ribs  228  within the housing  202  such that the first spacer ribs  228  define a cross-section (e.g., diameter) of the central channel  212  of the filter media  210 . Thus, the plurality of first spacer ribs  228  may be configured to facilitate proper positioning of the filter media  210  within the housing  202 , for example, positioning of the filter media  210  concentrically around the first central pillar  226 . 
       FIGS. 9-14  show various views of the second end cap  230  of the filter element  200 . The second end cap  230  comprises a second end cap main body  232 . A second plurality of indenting features  234  are positioned on the second end cap main body  232  proximate to the filter media second end opposite the filter media first end. The second plurality of indenting features  234  are configured to contact and indent corresponding segments of a filter media second end of the filter media  210  causing the plurality of filter media layers  214  to also interlock at the corresponding segments of the filter media second end, as described with respect to the first end cap  220 . The second end cap main body  232  defines a ring shaped structure defining an axial outlet  241  configured to allow filtered fluid to exit the filter element via the second end cap  230 . 
     The second end cap  230  may comprise a plurality of ribs  233  extending axially from the second end cap main body  232  into the housing  202 . The second plurality of indenting features  234  may also comprise a knife edge defined on an axial edge of each of a set  233   a  of the plurality of ribs  233 . As shown, the second plurality of indenting features  234  are positioned axisymmetrically on the second end cap main body  234  having a pitch of 120 degrees therebetween. In other embodiments, the second plurality of indenting features  234  may be equal in number to the first plurality of indenting features  224  and may be axially aligned with or offset from the first plurality of indenting features  224 . 
     In some embodiments, each of plurality of ribs  233  may also include flow vanes defining outlet flow channel therebetween. Filtered fluid (e.g., blowby gases) flowing axially through the flow paths between the plurality of filter media layers  214  may flow into the outlet flow channels defined between the plurality of ribs  233  and may be redirected to flow in a radial direction towards the axial outlet  241  defined in the second end cap main body  232  and out of the housing  202 . 
     The second end cap  230  may also include the second central pillar  236  and one or more second spacer ribs  238  extending from the second central pillar  236  towards a rim of the axial outlet  241 . The second central pillar  236  is axially aligned with the first central pillar  226  and extends towards the first central pillar  226 . The receptacle  237  of the second central pillar  236  is configured to receive the protrusion  227  of the first central pillar  226 , as previously described herein. Mating the protrusion  227  with the receptacle  237  may facilitate alignment of the first end cap  220  with the second end cap  230 . In some embodiments, the protrusion  227  may be configured to snap-fit or friction fit into the receptacle  237 , for example, to removably couple the first end cap  220  to the second end cap  230 . 
     A plurality of second spacer ribs  238  extend radially from the second central pillar  236  towards an inner rim of the second end cap main body  232 . The second spacer ribs  238  may be coupled to the second end cap main body  232  such that the second central pillar  236  is suspended over the axial outlet  241 , and a plurality of gaps defined between adjacent second spacer ribs  238  fluidly couple flow channels defined between the plurality of ribs  234 , an outer perimeter of the second central pillar  236  and an inner perimeter of the second end cap main body  232  to the axial outlet  241 . A plurality of second support pillars  239  may also be positioned around second central pillar  236 . Each of the second support pillars  239  define a protrusion  239   a  extending from an axial end thereof. The protrusions  239   a  are configured to be inserted into the corresponding aperture  229   a  defined in the corresponding first support pillar  229 , as previously described herein. 
     The filter element  200  may be positioned within the housing  202  on the first plurality of indenting features  224  of the first end cap  220 . The second end cap  230  may then be coupled to the first end cap  220 . The height of each of the first plurality of indenting features  224  and the second plurality of indenting features  234  are structured such that when the first end cap  220  is coupled to the second end cap  230 , the plurality of indenting features  224  and  226  indent corresponding segments of the filter media  210  at a first and second end thereof, respectively so as to interlock the plurality of filter media layers  214 , as previously described herein. 
       FIG. 15  is top view of the filter element  200  with the filter media  210  positioned within the housing  202 . The filter media  210  comprises the plurality of filter media layers  214  wound in a roll so as to form the filter media  210 . The second end cap  230  is removed to show a plurality of indentations  216  formed on the filter media second end of the filter media  210  by the second plurality of indenting features  234  of the second end cap  230 . As previously described, the plurality of filter media layers  214  interlock at the indentations  216  and also on corresponding indentations formed on the filter media at the filter media first end (not shown) by the first plurality of indenting features  224 , which prevents movement of the plurality of filter media layers  214  relative to each other when the filter element  200  is rotated or spun. 
       FIG. 16  is a schematic flow diagram of a method  300  for preventing movement of a plurality of filter media layers (e.g., the plurality of filter media layers  214 ) of a filter media (e.g., the filter media  110 ,  210 ) relative to each other when a filter element (e.g., the filter element  100 ,  200 ) including the filter media is rotated, according to an embodiment. The method  300  comprises providing a filter media, at  302 . The filter media may include, for example, the filter media  110 ,  210  and may include a plurality of filter media layers (e.g., the plurality of filter media layers  214 ). In particular embodiments, the plurality of filter media layers may be wound in a roll so as to form a cylindrical filter media. 
     At  304 , a filter media first end of the filter media is positioned on a first end cap comprising a plurality of a first flow vanes, a set of the plurality of flow vanes including a knife edge configured to contact and indent corresponding segments of the filter media first end. For example, the filter media  110 ,  310  is positioned within the housing  102 ,  202  on the first end cap  120 ,  220  comprising the first plurality of indenting features  124 ,  224 , as previously described herein. 
     At  306 , a second end cap is coupled to the first end cap or a filer media second end opposite the filter media first end. The filter media  110 ,  210  may be pushed down on the first end cap  120 ,  220 , for example, by the second end cap to cause the first plurality of indenting features  124 ,  224  of the first end cap  120 ,  220  to indent the filter media  110 ,  210  at the filter media first end. In some embodiments, the second end cap (e.g., the second end cap  130 ,  230 ) may also comprise a second plurality of indenting features (e.g., the second plurality of indenting features  134 ,  234 ) which may contact and indent the plurality of filter media layers at the filter media second end. In particular embodiments, the second end cap may comprise a plurality of ribs, a set of the plurality of ribs including a knife edge forming the second plurality of indenting features configured to contact and indent corresponding segments of the filter media second end opposite the filter media first end. For example, the second end cap  130 ,  230  is coupled to the housing  102 ,  202  causing the second plurality of indenting features  134 ,  234  the filter media second end. The indents caused by the plurality of first and second indenting features  124 ,  224  and  134 ,  234  causes the plurality of filter media layers  214  to interlock at the indents so as to prevent relative movement of the plurality of filter media layers  214 , which may cause the filter media  110 ,  210  to unwind, relative to each other. 
     It should be noted that the term “example” as used 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,” 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. 
     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. 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 embodiments described herein. 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any embodiment or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular embodiments. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.