Abstract:
A spin-on filter that eliminates the use of a nut plate and reduces the number of separate components. Instead, the spin-on filter utilizes the end plate of the filter cartridge to perform a number of functions, including closing the open end of the filter shell, sealing between the dirty and clean fluid sides, sealing between the filter and the mounting head to prevent leakage outside the filter to environment, attaching the filter cartridge to the shell, and sealing the end of the filter media.

Description:
FIELD 
       [0001]    This disclosure relates generally to a spin-on filter for use in fluid, for example oil or fuel, filtration that is configured for attachment to a mounting head without the use of a nut plate commonly used on filters of this type. 
       BACKGROUND 
       [0002]    Typical spin-on fluid filters according to some prior art designs are mounted to the mounting head by the use of an internally-threaded metal nut plate. The nut plate is anchored to the filter shell and includes at least one flow inlet and a flow exit. A spin-on filter with a nut plate often includes a large number of components that are required to form the filter which increases the cost and assembly complexity of the filter. 
         [0003]    Some known spin-on fluid filters eliminate the nut plate. Examples include U.S. Pat. Nos. 7,434,697 and 7,614,504. 
         [0004]    Whether or not the spin-on filter includes a nut plate, sealing must be provided between the head and the filter to prevent leakage outside the filter to environment, and sealing must be provided between the flow inlet and the flow exit to prevent leakage of unfiltered fluid from the inlet to the filtered fluid outlet. These sealing functions are typically provided by separate parts of the filter, including the use of installed sealing gaskets. 
         [0005]    Improvements to spin-on filters are desirable. 
       SUMMARY 
       [0006]    A spin-on filter is described that eliminates the use of a nut plate and reduces the number of separate components. Instead, the spin-on filter utilizes the top end plate of the filter cartridge to perform a number of functions, including closing the open end of the filter shell, sealing between the dirty and clean fluid sides, sealing between the filter and the mounting head to prevent leakage outside the filter to environment, attaching the filter cartridge to the shell, and sealing the end of the filter media. 
         [0007]    The filter is less expensive to fabricate, including cost savings by eliminating many of the components found in traditional spin-on filters. The reduced number of components also helps to reduce the weight of the filter. In addition, by integrating the multiple functionalities in the top end plate, separate sealing gaskets are avoided while providing a unique interface design. Also, eliminating the nut plate allows more space availability at the top of filter which can be utilized for maximized slit width or compact filter design. 
         [0008]    In one embodiment, the spin-on filter includes a shell having a closed end and an open end. The shell includes threads adjacent the open end that are configured to connect the shell to a mounting head. A filter cartridge is disposed within the shell that includes filter media suitable for filtering a fluid, including but not limited to oil or fuel such as diesel fuel. An end plate is attached to the filter media and is positioned adjacent to and closes the open end of the shell. The end plate has a perimeter edge that is attached to an end of the side wall of the shell which fixes the cartridge to the shell, a central fluid passageway in fluid communication with an inner space of the filter media, and a plurality of fluid passageways positioned between the perimeter edge and the central fluid passageway that are in fluid communication with the interior space of the shell. The end plate can also include first and second seals that are integrally formed therewith. The first seal is located adjacent to and is circumferentially continuous around the central fluid passageway to enable sealing with the mounting head to seal dirty fluid entering the filter from filtered fluid exiting the filter. The second seal is located adjacent to the perimeter edge and is circumferentially continuous on the end plate to enable sealing with the mounting head to prevent fluid leakage between the filter and the mounting head. 
         [0009]    The various functions of the end plate of the filter cartridge discussed above can be used separately from one another or in any combination of the functions. For example, the end plate can close the open end of the filter shell and can be used to attach the filter cartridge to the shell, but sealing is provided by seals other than seals integrally formed on the end plate. In another example, the end plate can include integral seals for sealing between the dirty and clean fluid sides and sealing between the filter and the mounting head to prevent leakage outside the filter to environment, and the end plate can substantially close the end of the filter shell, but the cartridge can be fixed to the shell in a manner other than by using the end plate. Other combinations of functions are possible for the end plate. 
         [0010]    The end plate can be formed of any material that is suitable to permit the first and second seals to perform their intended sealing functions. For example, the end plate can be formed of plastisol, polyurethane, a plastic with polyurethane, or other plastic material. 
         [0011]    The perimeter edge of the second end plate can be attached to the shell in any manner that is suitable for fixing the cartridge to the shell. The attachment can be detachable to permit replacement of the filter cartridge, or permanent in which case the entire filter will be disposed of. Examples of attachments include, but are not limited to, a snap fit connection between the perimeter edge and the shell, spin welding the side wall of the shell to the perimeter edge, or molding the perimeter edge with the end of the side wall of the shell. 
         [0012]    The threads used to connect the filter to the mounting head can be exterior threads or interior threads. The threads can be integrally formed on the side wall or can be formed on an attachment cap that is disposed adjacent to the open end of the shell and that is rotatable relative to the shell. 
         [0013]    The improved spin-on filter described herein has two main subassemblies, namely the filter cartridge and the shell. In addition, the top end plate of the filter cartridge is configured to perform a number of functions, many of which were performed by separate components in prior spin-on filter designs. Therefore, the number of component parts of the filter is reduced compared to prior spin-on filter designs, which reduces cost. In addition, using the top end plate to close the open end of the shell permits an increase in filter media area that can be used. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  illustrates an embodiment of the improved filter described herein in position to be mounted to a mounting head. 
           [0015]      FIG. 2  is a cross-sectional view of the filter of  FIG. 1  mounted to the mounting head. 
           [0016]      FIG. 3  is close-up view of the portion contained in box  4  in  FIG. 2 . 
           [0017]      FIG. 4  is a partial sectional view of the filter of  FIG. 1 . 
           [0018]      FIG. 5  is a cross-sectional view of the filter of  FIG. 1  showing the increase in slit width and pleat depth. 
           [0019]      FIG. 6  is a close-up view of the portion contained in box  5  in  FIG. 5 . 
           [0020]      FIG. 7  is close-up view of the portion contained in box  6  in  FIG. 5 . 
           [0021]      FIG. 8  illustrates the underside of the filter head. 
           [0022]      FIG. 9  illustrates another embodiment of an improved filter described herein mounted to a mounting head. 
           [0023]      FIG. 9A  is a close-up view of the portion contained in box  9 A in  FIG. 9 . 
           [0024]      FIG. 9B  is a close-up view similar to  FIG. 9A , but taken through one of the inlet openings in the end plate. 
           [0025]      FIG. 10  illustrates another embodiment of an improved filter described herein mounted to a mounting head. 
           [0026]      FIG. 11  is a close-up view of the portion contained in box  8  in  FIG. 10 . 
           [0027]      FIG. 12  illustrates another embodiment of an improved filter described herein mounted to a mounting head. 
           [0028]      FIG. 13  is a close-up view of another embodiment of sealing between the head and the filter. 
           [0029]      FIG. 14  illustrates another embodiment of an improved filter described herein mounted to a mounting head. 
           [0030]      FIG. 15  illustrates a cap used to mount the filter of  FIG. 14  to the head. 
           [0031]      FIG. 16  illustrates another embodiment of an improved filter described herein mounted to a mounting head. 
           [0032]      FIG. 17  illustrates another embodiment of a cap used to mount the filter of  FIG. 16  to the head. 
           [0033]      FIG. 18  illustrates an improved filter described herein next to a prior art filter using a nut plate in  FIG. 19 . 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    With reference initially to  FIGS. 1-7 , a spin-on fluid filter  10  in accordance with one embodiment is illustrated. The filter  10  is configured for detachable connection to a filter mounting head  12 . As used herein, the term spin-on refers to the use of rotation to effect connection and disconnection of the filter  10  to and from the head  12 . However, it is believed that the concepts described herein can be applied to other forms of connection between the filter and the head that do not require rotation. 
         [0035]    The fluid filter  10  will be described herein as being configured for filtering oil or fuel such as diesel fuel. However, it is contemplated that the concepts described herein can be utilized on filters that filter others types of fluid, including liquids such as water, and air. In addition, the filter will be described as being configured for outside-in flow of the fluid where the fluid flows generally radially inward through the filter media to a central space and then out through a central outlet. However, the concepts described herein can also be employed on a filter that is configured for inside-out flow of fluid where the fluid flows generally radially outwardly through the media during filtration. 
         [0036]    The head  12  includes an inlet  14  for dirty fluid to be filtered by the filter  10 , and an outlet  16  for filtered fluid that has been filtered by the filter. The inlet  14  is in communication with an interior circumferential space  18 , and the outlet  16  is in communication with an outlet space  20 . As shown in  FIGS. 1 and 2 , the head  12  includes a circumferential skirt  22  with interior threads  24  formed on the interior thereof for use in connecting to the filter  10 . A circumferentially continuous sealing surface  26  is formed on the interior of the head adjacent the base end of the skirt  22 . In addition, as shown in  FIGS. 1 ,  2  and  8 , a sealing rib  28  projects downwardly from the interior of the head toward the filter  10  radially inwardly from the sealing surface  26 . The rib  28  has an angled sealing surface  30  that faces generally toward the central axis of the filter. The space  18  is defined between the sealing surface  26  and the rib  28 . 
         [0037]    The filter head  12  is preferably configured to avoid sealing if one attempts to install an incorrect filter. For example, as shown in  FIG. 8 , the rib  28  has a plurality of spaced slots  32  provided in it to avoid axial sealing if an incorrectly configured filter is used with the head  12 . In addition, the rib  28  is provided with a plurality of half circular tabs  34  to avoid any radial sealing if an incorrectly configured filter is used with the head  12 . 
         [0038]    Returning to  FIGS. 1-5 , the filter  10  has two main subassemblies, namely a shell  40  and a filter cartridge  42  that is disposed within the shell. The shell  40  can be formed of metal which allows the shell to be made thin. However, the shell can be formed of other materials, including plastic, if the shell is able to withstand the operating environment, including bearing loads and pressure, of the filter. 
         [0039]    The shell  40  has an end wall  44  defining a closed end of the shell, and a side wall  46  extending from the end wall. The side wall  46  has an end  48  opposite the end wall  44  that defines an open end of the shell. The end wall  44  and the sidewall  46  define an interior space  50  of the shell between the closed end and the open end which is sized to receive the filter cartridge  42  therein. As best seen in  FIGS. 1-5 , the end  48  of the side wall includes exterior threads  52  adjacent the open end that are configured to engage with the threads  24  on the head to connect the filter to the head. In one embodiment, the shell  40  can be an extruded shell with the threads  52  formed by a rolling, spinning or other forming operation as per DIN 7273 standard or with any specific thread profile. 
         [0040]    The filter cartridge  42  includes filter media  60  that is suitable for filtering the fluid with which the filter will be used. One example of a suitable filter media  60  is a pleated cellulose media. However, other types of filter media can be employed including, but not limited to, multiple media layers and non-pleated media. As described further below, the use of pleated media is advantageous since the use of an end plate that closes the open end of the shell permits an increase in the slit width and the pleat depth of the pleated media, which increases the media area. However, similar increases in media area would be achieved with non-pleated media. 
         [0041]    The media  60  is arranged in a generally cylindrical shape and defines an inner space  62 . A plastic or metal center tube  64  is disposed in the inner space  62  and supports an interior surface of the filter media  60 . The center tube  64  has a first end that is potted in the bottom end plate as described below, and a second end  66  that is surrounded by the upper end plate (described further below) and which helps defines a filtered fluid outlet of the filter. 
         [0042]    A first or bottom end plate  70  is attached to a first end of the filter media  60  adjacent to the closed end of the shell. Likewise, a second or upper end plate  72  is attached to a second end of the filter media and is positioned adjacent to and closes the open end of the shell. The end plates  70 ,  72  seal the ends of the media  60  to prevent fluid from flowing axially through the ends of the media, so all of the fluid flows generally radially through the media. 
         [0043]    In the illustrated embodiment, the ends of the media  60  are attached to the end plates  70 ,  72  using an over molding process where the end plates  70 ,  72  are molded around the ends of the media and the ends of the center tube. During molding, each end of the media  60  and center tube  64  assembly is placed in a mold cavity. Polyurethane, plastisol, plastic with polyurethane, or other plastic material potting compound is introduced into the cavity and when cured, the ends of the media and the center tube become intimately bonded with the cured material and forms the end plates  70 ,  72  that are integral structures with the media and the center tube. 
         [0044]    However, it is contemplated that the media, center tube and the end plates can be attached in other manners, including by embedding the ends of the media and the center tube into pre-formed endplates, by using an adhesive, or through other suitable attachment means. 
         [0045]    For ease of construction, the end plates  70 ,  72  are preferably formed of the same material. However, the end plates  70 ,  72  can be formed of different materials if it is necessary or considered beneficial in order to implement the intended sealing functions of the second end plate  72  as discussed further below. The material(s) used to form the end plates can be any material(s) that is suitable to perform the intended functions of the end plates  70 ,  72 . For example, the end plates can be formed of plastisol, polyurethane, a plastic with polyurethane, or other plastic material. 
         [0046]    As shown in  FIGS. 1-5 , the first end plate  70  is closed which means that there are no fluid passageways therethrough. However, in other embodiments, depending upon the intended function of the filter media, one or more openings could be provided at certain locations in the first end plate  70 , for example to allow separated water to flow to a sump area. Filters designed with a filter-in-filter construction or filters with hydrophobic media designs typically use this type of end plate with openings construction. A plurality of tabs  71  are formed on the bottom of the end plate  70  during the molding operation. The tabs  71  act as stoppers for the cartridge  42  when it is being inserted into the shell  40 . The tabs  71  allow the spring which is normally used in conventional spin on filters to be eliminated. In addition, the tabs  71  also help to locate the cartridge  42  in the shell  40 . 
         [0047]    With reference to  FIGS. 4 and 5 , the second end plate  72  includes a perimeter edge  74  that is attached to the end  48  of the side wall of the shell, a central filtered fluid outlet passageway  76  in fluid communication with the inner space  62 , and a plurality of dirty fluid inlet passageways  78  positioned between the perimeter edge  74  and the central fluid passageway  76  in fluid communication with the interior space  50 . 
         [0048]    As shown in  FIG. 5 , the second end plate  72  extends across the entire open end of the shell, closing the open end. As best seen in  FIGS. 4 and 5 , the perimeter edge  74  is attached to the end  48  by overmolding the second end plate  72  onto the end  48  which fixes the filter cartridge to the shell. Therefore, during the intended use of the filter when it is mounted on the head  12 , the only way for fluid to enter the filter  10  is through the passageways  78 , and the only way for fluid to exit the filter is through the passageway  76 . 
         [0049]    In addition to over molding the end plate  72  onto the end  48 , the end plate  72  is also molded over the second end  66  of the center tube  64  as discussed above. In addition, the first end plate  70  is also over molded the first end of the center tube  64 . 
         [0050]    With reference to  FIGS. 2-5 , the second end plate  72  includes a first seal  80  that is configured to seal with the sealing rib  28  to seal dirty fluid entering the filter from filtered fluid exiting the filter, and a second seal  82  that is configured to seal with the sealing surface  26  to prevent fluid leakage between the filter and the mounting head. The seals  80 ,  82  are integrally formed with, and formed from the same material used to form, the end plate  72 . 
         [0051]    The first seal  80  is located adjacent to, and is circumferentially continuous around and defines, the central fluid passageway  76 . The first seal  80  includes an angled surface  84  that engages with and seals against the angled surface  30  on the sealing rib as shown in  FIGS. 2 and 3 . The second end  66  of the center tube  64  provides support to the seal  80 . Therefore, angular sealing is achieved by compression of the seal  80  between two solid permanent parts of the center tube  64  and the angled surface of the sealing rib  28 . This forms the sealing for the clean and dirty side. This angularity in the sealing also provides alignment and it will also compensate for radial variation due to the threads  52  during assembly of the filter  10  with the head  12 . 
         [0052]    The second seal  82  is located adjacent to or at the perimeter edge  74  and is circumferentially continuous on the second end plate. The second seal  82  is configured to engage and seal against the sealing surface  26  as shown in  FIGS. 2 and 3 . 
         [0053]    Use of the filter  10  is as follows. The filter  10  is brought toward the head  12  as shown in  FIG. 1 , and then threaded onto the head using the threads  24 ,  52  as shown in  FIG. 2 . When completely threaded onto the head, the angled surface  84  of the seal  80  seals against the angled surface  30  of the sealing rib  28 , while the seal  82  seals against the sealing surface  26 . If an incorrectly designed filter is installed, the filter will not correctly seal against the angled surface  30 , and the slots  32  and/or tabs  34  on the rib  28  will permit fluid leakage. 
         [0054]    The flow of fluid in the filter is shown by the arrows in  FIG. 2 . Fluid to be filtered flows into the head via the inlet  14 , flows into the space  18 , and then flows through the passageways  78  in the end plate  72  into the filter as shown by the arrows. The fluid then flows generally radially inwardly through the filter media, through openings in the center tube and into the inner space  62 . The filtered fluid then flows upwardly through the outlet passageway  76 , into the space  20  and then exits via the outlet  16 . 
         [0055]      FIGS. 9 ,  9 A and  9 B illustrate another embodiment of a filter  100  which is similar in many respects to the filter  10 . Therefore, only the differences from the filter  10  will be described in detail, and features that are similar to features in the filter  10  will be designated with the same reference numerals. As shown in  FIG. 9 , the head  102  is configured similar to the head  12  with respect to the fluid inlet and the sealing surface  26 . 
         [0056]    The filter  100  primarily differs from the filter  10  with respect to the center tube and fluid outlet design. The second end plate  73  includes a first seal  90  that is configured for radial sealing with an outlet tube  91  of the head while the seal  82  seals against the sealing surface  26 . In addition, the filter  100  includes a center tube  108  where the first end is embedded in the first end plate  70  as in the filter  10 . However, the second end of the center tube  108  is simply potted into the second end plate  73  at a location between the seal  90  and the seal  82  as best seen in  FIGS. 9A and 9B . 
         [0057]    As shown in  FIGS. 9A and 9B , the perimeter edge  74  of the end plate  73  is attached to the end  48  of the shell by overmolding the second end plate  73  onto the end  48  which fixes the filter cartridge to the shell. 
         [0058]      FIGS. 10 and 11  illustrate an embodiment of a filter  120  that employs a differently configured second end plate  122 . The end plate  122  includes a first seal  124  that is configured for radial sealing with an outlet tube  126  of the head. The end plate  122  also includes a second seal  128  formed by an axially projecting rib with an inner surface  130 , and an angled outer surface  132 . The seal  128  fits into a channel formed in the head between an inner rib  134  and an outer rib  136 . The angled outer surface  132  engages and seals against an angled surface on the outer rib  136 , while the inner surface  130  seals against a surface of the inner rib  134 . 
         [0059]    In addition, the end plate  122  includes a perimeter edge  140  that is shaped as a circumferentially continuous rounded bead. The beaded edge  140  is configured to snap fit connect with a rounded end  142  of the shell. This snap fit connection would permit replacement of the filter cartridge at the end of its useful life. Instead of a snap fit connection, the end  142  and the perimeter edge  140  can be spin welded together. Spin welding of filter parts is known in the art. 
         [0060]      FIG. 12  illustrates an embodiment of a filter  150  that employs a differently configured second end plate  152 . In this embodiment, the end plate  152  includes a first seal  154  that is configured for radial sealing with an outlet tube  156  of the head. The end plate  152  also includes a second seal  158  that engages and seals against a sealing surface  160  that is similar to the sealing surface  26  in  FIG. 9A . In addition, the end plate  152  includes a perimeter edge  162  that includes a circumferentially continuous, radial groove  164  that is configured to snap fit connect with a rounded end  166  of the shell. This snap fit connection would permit replacement of the filter cartridge at the end of its useful life. Instead of a snap fit connection, the end  166  and the perimeter edge  162  can be spin welded together. 
         [0061]      FIG. 13  illustrates another embodiment of a second end plate  180  with a second seal  182  that has a rounded edge  184  that engages and seals with a rounded sealing surface on the head. A first seal  186  is configured for radial sealing with an outlet tube of the head. 
         [0062]      FIGS. 14 and 15  illustrate an embodiment of a filter  200  where the threads that connect the filter  200  to the head are formed on an attachment cap  202  disposed adjacent to the open end of the filter and that is rotatable relative to the shell. An upper end  204  of the shell is flared outwardly and defines a shelf  206 . The cap  202  includes a bottom end that engages the shelf  206 , and an upper end that is internally threaded  208  for engagement with exterior threads on the head. 
         [0063]    The filter  200  also includes a second end plate  210  with a first seal  212  that is configured similar to the first seal  154  in  FIG. 12 , and a second seal  214  at a perimeter edge  216 . The perimeter edge  216  defines a radial slot that receives the end of the shell, where the second seal  214  defines the upper side of the slot and which seals with a sealing surface on the head. This construction permits the end plate  210  to be snap fitted into the shell. Alternatively, the end of the shell and the end plate  210  can be spin welded together. Also, the attachment cap  202  is loosely fitted on the end of the filter  200 . This permits the filter to be removed from the attachment cap  202  to allow replacement of the filter  200 . 
         [0064]      FIGS. 16 and 17  illustrate another embodiment of a filter  231  which is similar in many respects to the filter  100  in  FIG. 9 . Therefore only differences from the filter  100  will be described in detail and features that are similar to features in the filter  100  will be designated with same reference numerals. As shown in  FIG. 16 , the head  230  is configured similar to the head  102  shown in  FIGS. 9 ,  9 A and  9 B, including fluid inlet and fluid outlet, and a similar sealing surface  26  and outlet tube  91 . 
         [0065]    The filter  231  primarily differs from the filter  100  with respect to the shell, which has no threads formed on it, and the connecting arrangement that connects the filter  231  to the filter head  230 . The filter  231  is connected to the head  230  in a similar manner to the filter  200  as shown in  FIG. 14 , where the threads that connect the filter  231  to the head  230  are formed on an attachment cap  236  disposed adjacent to the open end of the filter shell  232  and that is rotatable relative to the shell. The cap  236  includes a bottom end  238  that engages a shelf  233  formed on the shell  232  and an upper end that is internally threaded  237  for engagement with exterior threads  239  on the head  230 . 
         [0066]    The lower, non-illustrated portions of the filters in  FIGS. 10-14  and  16  can be similar to the lower filter portions illustrated in  FIGS. 1-2  and  9 , or they can have a different configuration than in  FIGS. 1-2  and  9 . 
         [0067]    With reference to  FIGS. 18 and 19 , a filter  250  constructed in accordance with the concepts described herein is illustrated next to a prior art filter  300  that uses a nut plate. As described above, the filter  250  has two main subassemblies, namely a shell and a filter cartridge, where the filter cartridge comprises filter media, a center tube, a molded bottom endplate and a molded top endplate that is fixed at its perimeter edge to the shell to close the open end of the shell and which defines first and second seals. Avoiding the nut plate allows more space availability at the top of the filter, which can be used to increase the slit width of the filter media (shown in  FIG. 5 ) resulting in increased filter media area, or used to reduce the axial length of the filter. In addition, since the molded top end plate extends to and closes the open end of the shell, the pleat depth of the filter media (shown in  FIG. 5 ) can be increased, resulting in increased filter media area. 
         [0068]    In contrast, the prior art filter  300  includes all of the components listed in  FIG. 19 . In addition, the presence of the nut plate results in an increase in the axial length of the filter  300  compared to the axial length of the filter  250 . 
         [0069]    The invention may be embodied in other forms without departing from the spirit or novel characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.