Abstract:
A sock style filter is disclosed that incorporates the embossing of filtration media to create rigid raised geometry embodiments that prevent collapse between the upper and lower filtration media sides of the filter to maintain and ensure a flow passage of fluid inside the filter for flow to the pump or downstream system. The embossed rigid embodiments keep the filtration media from collapsing under suction and eliminates the use of secondary inserted structures; such as a plastic comb or folded net, or injection mold plastic ribs or bones onto or around the filtration media.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/001,922 filed on May 22, 2014, entitled “FORMING FILTRATION MEDIA FOR MAINTAINING FLOW PASSAGE THROUGH A SOCK STYLE FILTER,” the entire contents of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to a filter, such as a filter used inside a liquid tank, and more particularly relates to embossing the flexible filtration media of the filter to create rigid formations that prevent the filter arrangement from collapsing under suction, thereby effectively ensuring a flow passage of liquid leading to the fuel pump or downstream system. 
       BACKGROUND 
       [0003]    A conventional sock style in-tank fuel filter is comprised of filtration media and a connector that attaches the filter to a fuel pump, tube or pipe for suctioning fluid through the filter. The filtration media is typically comprised of flexible, non-rigid, draping cloth. The filtration media is formed into a sock structure and used for filtering or removing contamination from a fuel or other liquid. The liquid that flows through a sock style filter is most often directionally flowing from the outside of the filter to the inside. Attached to a portion of the filtration media is a metal or plastic connector that is used to attach the filter to a fuel pump, tube or pipe or other suction flow apparatus. The outside to inside flow direction through the filtration media to this connector creates suction inside the filter, which in turn causes the filtration media on the two sides of the filter to move towards and/or against each other, whereby one side of filtration media will compress against the filtration media on the opposite side of the filter. If allowed to press against each other, this suction force can close off the liquid flow through the filter. 
         [0004]    Conventional designs use a secondary inserted structure; such as a plastic comb, supportive netting, or injection mold plastic ribs or bones, onto or around the filtration media; to keep the two sides of the filter from compressing together and reducing or blocking the fluid flow. The inserted or injection molded component creates a rigid geometric shape structure of the filter. The drawbacks to this supportive structure is the heightened potential for the presence of dust, dirt, or foreign particles created during the insertion process, or deterioration of the inserted component, and the added cost associated with the insertion process in materials, tooling and labor. 
         [0005]    Another aspect of the conventional design is the function of the inserted component as the structure that keeps the filter body rigid and positioned in a flat orientation. A rigid filter structure is also needed to maintain the positioning of the filter inside a fuel tank in the area where the fuel is present. For example, a non-flexible draping cloth without a rigid body structure may fold or bend upwards and become positioned in the air space above the fuel fluid level. Exposure to air may allow air to be drawn into the filter and pass to the system causing flow cavitation and reduced fluid volume. 
       SUMMARY 
       [0006]    In one embodiment of the present disclosure a sock style filter includes filtration media that maintains its position and keeps from collapsing under suction without the additional insertion of a plastic comb, netting, ribs or bones. The filtration media is embossed to create a rigid raised geometry on a surface of the filtration media that is oriented to keep the two sides of the filter separated, thereby effectively ensuring a flow passage of liquid leading to the fuel pump or downstream system. The filter thus generally comprises the filtration media without internal combs or ribs, and a plastic connector attached to the filtration media for connection to a pump. 
         [0007]    Embossing, as used herein, is a process to mold a raised geometric design into a layer of material. The embossing of the filtration media can be performed inside the injection mold during molding of the plastic connector attached to the filter. The embossing can also be performed outside the injection mold with a die or other means of compression or permanent deformation. The embodiments of the present disclosure according to the foregoing provide a filter that is simpler to manufacture and has few internal components that can wear or deteriorate over time causing contamination inside the filter. This eliminates potential sources of creating internal contamination that may move with the fluid flow downstream and damage the system the filter is intended to protect from such damage. Eliminating the need to insert a plastic comb or netting inside the filter or injection mold a set(s) of ribs or bones onto or around the filtration media also reduces the complexity and cost of the injection mold and process tooling. 
         [0008]    One implementation of the filter creates long embossed areas or strips on one or both sides of the filtration media that function as rigid formation to maintain an open pocket inside the filter. In another implementation, the invention creates multiple patches or localized areas of emboss on one or both sides of the filtration media that function as rigid formations to maintain a rigid body structure and an open pocket inside the filter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a diagrammatic, side elevation view of a motor vehicle fuel tank having a pump module that can incorporate the filtration media described herein. 
           [0010]      FIG. 2  is an enlarged, fragmentary sectional view of an implementation of filtration media used for embossing in accordance with the disclosure. 
           [0011]      FIG. 3  is a sectional view of a tool for embossing filtration media. 
           [0012]      FIG. 4  is a top side detailed pictorial view of an embodiment of a filter with top and bottom areas of dotted embossing formations in the filtration media in accordance with the disclosure. 
           [0013]      FIG. 5  is a bottom side detailed pictorial view of  FIG. 3  in accordance with the disclosure. 
           [0014]      FIG. 6  is a top side cut away view of the filter in  FIG. 3  and  FIG. 4  in accordance with the disclosure. 
           [0015]      FIG. 7  is a top side detailed pictorial view of an alternate embodiment of a filter with top and bottom areas of long embossing formations in the filtration media in accordance with the disclosure. 
           [0016]      FIG. 8  is a bottom side detailed pictorial view of  FIG. 6  in accordance with the disclosure. 
           [0017]      FIG. 9  is a top side cut away view of the filter in  FIG. 6  and  FIG. 7  in accordance with the disclosure. 
           [0018]      FIG. 10  is a top side detailed pictorial view of a preferred embodiment of a filter with areas of oblong embossing formations only on one side of the filtration media in accordance with the disclosure. 
           [0019]      FIG. 11  is a bottom side detailed pictorial view of  FIG. 9  and the preferred embodiment of a filter with areas of oblong embossing formations in the filtration media in accordance with the disclosure. 
           [0020]      FIG. 12  is a top side cut away of the filter in  FIGS. 9 and 10  in accordance with the disclosure. 
           [0021]      FIG. 13  is a top side detailed pictorial view of an alternate embodiment of a filter with areas of long curving embossing formations on side and long straight embossing formations on the opposite side of the filtration media in accordance with the disclosure. 
           [0022]      FIG. 14  is a bottom side detailed pictorial view of  FIG. 12  in accordance with the disclosure. 
           [0023]      FIG. 15  is a top side cut away view of the filter in  FIGS. 12 and 13  in accordance with the disclosure. 
           [0024]      FIG. 16  is a schematic cross-sectional view of an alternate embodiment of a filter. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    The present disclosure includes many embodiments of filtration media that are embossed, as described further herein, and preferably utilized in filters defining an enclosed interior space such as sock style filters used for a number of fluids including, but not limited to, fuel such as unleaded fuel or diesel fuel, hydraulic fluid, lubrication oil, urea, and other fluids (both liquid and gaseous). For convenience, the filter structure will be described herein as being for use in fuel filtration. To help describe the concepts of the filtration media,  FIG. 1  illustrates an in-tank housed fuel module of a motor vehicle in which the filtration media described herein can be used. The filtration media can be incorporated into the suction filter  10  located at the bottom of the fuel module. The construction and operation of in-tank housed fuel modules is well known in the art. Other uses of the disclosed filtration media are possible and include various fuel filters disposed both inside and outside a fuel tank and other fluid filters as parts of machines having a suction system such as a pump or vacuum. 
         [0026]    Referring to  FIG. 2 , one implementation of a filtration media  20  that can be embossed in accordance with the teachings of the present disclosure is illustrated. The filtration media  20  may include multiple layers of filter media suitable for filtering fuel such as a gradient depth filter media  22  comprising a plurality of non-woven layers  22   a ,  22   b,    22   c,  preferably of melt blown filaments. Examples of gradient density melt blown filtration media layers are known in the art, suitable examples of which are disclosed in the following references: U.S. Patent Application Publication No. 2006/0266701, U.S. Pat. No. 6,613,227, and U.S. Pat. No. 7,927,400, each of which are incorporated herein by reference in their entirety. 
         [0027]    The filtration media  20  may also include two carrier layers  24  and  26  of non-woven filtration media, e.g. spun bond layers, which can include static dissipative elements. The filtration media  20  may also include an exterior shell layer  28  opposite the interior space  30  within the filter (also referred to herein as the pocket), and one or more channel depth layers  32 ,  34  positioned adjacent the depth filter media  22 . A preferred channel depth filtration media is disclosed in U.S. Publication No. 2014/0202951, the content of which is hereby incorporated by reference in its entirety. 
         [0028]    It has been discovered that, through proper construction of the exterior shell layer  28  and/or the channel depth layers  32 ,  34 , i.e. as an embossing layer, the filtration media  20  may be subject to an embossing procedure to provide embossed areas  50  having sufficient size and strength to maintain the interior space  30  between upper and lower portions of the filtration media  22  and prevent collapse and blockage. In one form, the exterior shell layer  28  is constructed of a mesh of plastic or polymer material, and in the case of fuel filters a suitable fuel tolerant and impervious plastic, e.g. nylon, polyester, acetal or Teflon™. The plastic mesh may be an extruded mesh or woven mesh. The exterior layer  28  is formed to have a thickness greater than 500 micron, or greater than 900 micron, or greater than 1200 micron, or greater than 1400 micron. The thickness preferably does not exceed 5000 micron. 
         [0029]    The optional channel depth layers  32 ,  34  may also be constructed from a plastic mesh to provide addition support for embossing. The mesh may be extruded or woven, and formed to have a nominal thickness greater than 250 micron, or greater than 500 micron, or greater than 600 micron, or greater than 900 micron. The thickness preferably does not exceed 2500 micron. Alternatively, the exterior shell layer  28  may be eliminated or formed of alternate materials, while at least one of the channel depth layers  32 ,  34  (or the combined thickness thereof) is formed with a nominal thickness greater than 500 micron, or greater than 900 micron, or greater than 1200 micron, or greater than 1400 micron. That is, one embossing layer of the filtration media  20  has a thickness, or a combination of multiple embossing layers have a combined thickness, that is greater than 500 micron, or greater than 900 micron, or greater than 1200 micron, or greater than 1400 micron, or greater than 1650 micron. The embossing layer(s) may be the exterior layer  28 , placed within the melt blown layers  22   a,    22   b,    22   c  (such as one or more channel depth layers  32 ,  34 ), or may be placed immediately adjacent one of the carrier layers  24 ,  26  (including to form a new interior layer directly exposed to the interior space  30 ), or a combination thereof. 
         [0030]    With reference to  FIG. 3 , embossing of the filtration media  20  is used to provide deep embossed areas  50  that are 2 to 15 mm in height that project or indent into the interior space  30  of the filter. The media  20  has at least one embossing layer of extruded plastic mesh that when compressed will take a permanent emboss and create rigid structures to keep upper and lower portions of the filter separated without a secondary support structure. This structure can be embossed on the top, bottom or both sides of the filtration medias  20 . A deep emboss of 2 to 15 mm is used to maintain a flow path for fluid inside the filter. 
         [0031]    In one form, an upper die  40  and a lower die  42  are used to clamp the filtration media  20  along the periphery  52  of the embossed area  50 , e.g. prior to being formed as a sock or other structure defining the interior space  30 . The lower die  42  includes a pocket  44  in the desired cross-sectional shape of the embossed area  50 , which also corresponds to the exterior shape of a pin or other tool  46 . The tool  46  preferably has a flat crown, i.e. a flat surface at its distal head, with rounded edges so as not to completely crush the layers of filtration media to keep porosity open for fluid flow therethrough. This cross-sectional shape is preferably tapered, e.g. a pyramidal or frusto-conical shape having rounded edges. The tool  46  may optionally be heated to enhance pliability of the plastic embossing layer and assist with the embossing process. The embossed area  50  is stretched by the tool  46  into the desired shape defined by the tool  46  and lower die  42 . The periphery  52 , and to some extent the embossed area  50 , may be compressed or crushed by the dies  40 ,  42 , such that these portions of the media  20  have an overall thickness less than the thickness of the remainder of the media  20 , and are sufficiently rigid to maintain the embossed shape under typical suction forces. Factors that may need to be controlled during the embossing process include, but are not limited to, tool/pin design, pressure, speed, heat and die depth. 
         [0032]    In other forms, the embossing of the filtration media  20  can be accomplished through the application of variations in combinations of heat, vacuum and pressure to create the rigid structure that is moved out of plane from the remaining portion of the filtration media  20 . Embossing is defined herein as a process to mold or carve in relief; stud; to shape, support, or provide with a rib or ribs/or to make the ridges or raised markings. The embossed areas thus provide a permanent, rigid, discontinuity in the surface or planarity of the filtration media, and preferably include corresponding discontinuities in all of the layers of the media  20  from the exterior surface to the interior surface. 
         [0033]    Those skilled in the art may alternately identify the method used for embossing as a thermoforming process. Thermoforming is a process term that relates to the process to create projections on the surface of materials with heat, vacuum or pressure. Thermoforming is a manufacturing process where a plastic sheet or flat form is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or “film” when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that it can be stretched or embossed in a mold and cooled to a finished shape. Preferably, the embossing or thermoforming process is accomplish using molding tools that can also mold the pump attachment to the filtration media, and is thus performed immediately before, immediately after, or at the same time as molding the pump attachment. Alternatively, the filtration media can be embossed utilizing a specialized tool and then stored for later use (e.g. by rolling the media into a roll), such as later injection molding of the pump attachment using other tools. 
         [0034]    In the embodiments of the present disclosure, the embossed filtration media  20  is then formed into a filter, such as filter  60  shown in  FIGS. 4-6 , having at least a first portion  62  and a second portion  64  (also referred to herein as top/upper and bottom/lower walls or portions based on their typical installation orientation), having an enclosed shape such as a sock style filter, where the media  20  is rolled or folded and the free edges are sealed together using known processes, to form an enclosed interior space. The embossed areas  50  create separation and structure to keep the top and bottom walls  62 ,  64  of filtration media separated while fluid flows through the in-tank filter  60 . The embossing layers of the media  20  has the structural integrity and strength to be compressed with a deep emboss pattern of 2-15 mm, or 4-10 mm, or about 6 mm, that allows for maintaining a pocket (interior space  30 ) inside the filter for allowing fluid flow. That is, and as best seen in  FIG. 6 , the upper wall  62  and lower wall  64  each generally extend in an upper and lower plane, and the frusto-conical embossed areas  50  project inwardly from the respective plane towards the interior space  30  (and the opposing wall) a depth D (depth also referred to herein as height). At the respective planes of media  20 , the embossed areas  50  have a width W 1  that is greater than a width W 2  at the peak of the embossed area  50 . In this way, the filter does not need to include any internal supportive structure, combs or ribs in the interior space  30 . 
         [0035]    The embossed areas  50  can have various depths, widths and lengths based on the overall thickness of the media  20 , which typically is 0.5-3.5 mm, and usually 1.5-2.5 mm. The emboss depth D is variable but recommended to be distanced from the surface or plane of the filtration media of at least 2 mm and up to 15 mm. This is only a common range of usage and the depth could be more than 15 mm without any measureable affect or benefit on fluid flow, media separation or filter rigidity. The ratio of the embossing depth to media thickness is preferably 100% to 2000%, and more preferably greater than 300%. The area of each upper and lower wall  62 ,  64  is preferably comprised of 5%-50% embossed areas  50 , and more preferably 10%-20% although any percentage of the area may be embossed while still maintaining the interior space  30  and fluid flow. As will be illustrated in selected embodiments, the embossed areas  50  may be different on the top and bottom portions  62 ,  64  of the filter  60 , e.g. either in size (width or depth), shape or relative position to a vertical axis, to allow for the fuel flow through the pocket  30  via the combination of embossed areas  50  on the upper and lower walls  62 ,  64 . 
         [0036]    The embossing method of the present disclosure includes the creation of protrusions or bumps having various sizes and shapes, i.e. varying in width and lengths, circular, square, rectangular or oblong shaped dots or pins, each forming an embossed area  50  that is compressed (e.g. reduced thickness of the media  20 ) and stretched, whereby the filtration media  20  creates permanent deformations. These deformed areas would rest against the filtration media  20  on the opposite side of the filter, e.g. project inside of a sock filter and maintain an open pocket  30  inside the filter for fluid flow and provide rigidity to the filter to provide a filter structure and overall geometric shape. 
         [0037]    Referring again to  FIGS. 4-6 , the embossed areas  50  illustrated are formed as dots or points on both the top and bottom walls  62 ,  64  of the filter  60  and provide separation between the top and bottom of the filter  60  to keep the interior space  30  open. Stated another way, the embossed areas  50  are each a discontinuity having a frusto-conical shape. This embossing ensures the media  20  does not collapse against the top and bottom portions or sides and reduce or block off the flow of fluid through the filter  60 .  FIG. 5  shows the bottom side of the same filter  60  with the images of the staggering of the dots with respect to the top and bottom sides of the filter. That is, the embossed dots  50  on the upper portion  62  are not radially aligned relative to a vertical axis (e.g. an axis passing through the inlet fitting) with the embossed dots  50  of the lower portion  64 . The embossed dots  50  on each side  62 ,  64  are preferably spaced apart in an array or grid.  FIG. 6  is a cut away of the same filter in  FIG. 4  and  FIG. 5  and shows how the embossed dots  50  provide a separation space  66  between the top and bottom walls  62 ,  64  of the filter  60 . 
         [0038]    Referring to  FIG. 7 , an implementation of a filter  70  is shown having long strips of embossed areas  50   t  running the length of the upper wall  72  of the filter  70 . That is, the embossed areas  50   t  have a channel shape and extend laterally relative to a vertical axis (or longitudinally relative to the filter  70 ).  FIG. 8  shows the bottom wall  74  of the filter  70  with embossed strips  50   b  running in the opposite direction (i.e. at an angle relative to the direction of the upper embossed strips  50   t,  e.g. 90 degrees) to provide rigid formations that press against each other.  FIG. 9  is a cut away of the filter  70  of  FIG. 7  and  FIG. 8 , and shows how the embossed areas  50   t,    50   b  provide a separation space  76  between the top and bottom portions  72 ,  74  of the filter. 
         [0039]    Referring to  FIG. 10 , an implementation of a filter  80  is shown having shorter strips of embossed areas  50   b  on a lower wall  84  of the filter. Stated another way, the embossed areas  50   b  each are essentially a rectangular dot.  FIG. 11  shows the top wall  82  of the filter  80 , which does not have any embossed areas.  FIG. 12  is a cut away of the filter  80  of  FIG. 10  and  FIG. 11 , and shows how the embossed areas  50   b  provide a separation space  86  between the top and bottom portions  82 ,  84  of the filter  80 . 
         [0040]    Referring to  FIG. 13 , an implementation of a filter  90  is shown having curving strips of embossed areas  50   t  on an upper wall  92  of the filter. The curvature generally follows a sinusoidal pattern, although other curvatures can be used.  FIG. 14  shows the bottom wall  94  of the filter  90  with the long, straight embossed areas  50   b  to provide rigid formations that set against to upper embossed areas  50   t.    FIG. 15  is a cut away of the filter  90  of  FIG. 13  and  FIG. 14  and shows how the embossed areas  50   t,    50   b  provide a separation space  96  between the top and bottom portions  92 ,  94  of the filter  90 . That is, where the upper embossed areas  50   t  align with the lower embossed areas  50   b,  the embossed areas can press against each other to further maintain the interior space  96 . 
         [0041]    Referring to  FIG. 16 , an implementation of a filter  100  is shown having embossed areas  50   t  in the upper wall  102  of the filter  100  that have a depth greater than the height of the interior space  106 . That is, the embossed areas  50   t  have a depth such that they push into the lower wall  104  and deform corresponding portions of the lower wall  104  downwardly from a plane of the lower wall  104  to form protrusions  108 . In this way, the protrusions  108  can act as feet to keep the remainder if the lower wall  104  off the bottom of the tank (such as in a fuel tank), thereby allowing fluid flow through all surfaces of the filter  100 . 
         [0042]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
         [0043]    The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.