Abstract:
A fluid filter assembly includes a housing having a closed end and an open end; a filter element operably oriented in the housing; a baffle plate mounted to operably cover the housing open end; the baffle plate including a first axial face and an outer circumferential wall circumbscribing the first axial face; the outer circumferential wall being groove-free; the first axial face defining at least a first sealing groove; and a sealing gasket oriented in the first sealing groove; the sealing gasket forming a seal between the housing and the baffle plate. Methods of constructing, installing, and servicing includes fluids filters of the type described.

Description:
This application is a divisional application of application Ser. No. 10/132,982, filed Apr. 26, 2002, now U.S. Pat. No. 6,823,996. Application Ser. No. 10/132,982 is incorporated by reference herein. 

   TECHNICAL FIELDS 
   This disclosure concerns generally a fluid filter. In particular, this disclosure relates to a filter incorporating an improved seal arrangement. 
   BACKGROUND 
   Filters have been employed in a variety of applications including hydraulic systems and engine lubrication systems. Such filter assemblies generally include a cylindrical filter element within a can or housing with a baffle or attachment plate at one end to connect the filter to a filter head, typically by a threaded joint. A central opening and several surrounding openings in the baffle direct flow through the filter and, in particular, the filter element. The flow can be in either an inside-out (forward flow) or an outside-in (reverse flow) pattern. A circular gasket serves as a seal between the baffle and the can or housing. 
   Various models and designs of filters have been known over the years. Each design improves on an aspect of these filters. Continued improvement in filters are desired. 
   SUMMARY OF THE DISCLOSURE 
   In one aspect, a fluid filter assembly is provided. The fluid filter assembly includes a housing having a closed end and an open end; a filter element operably oriented in the housing; a baffle plate mounted to operably cover the housing open end; the baffle plate including a first axial face defining at least a first sealing groove; and a sealing gasket oriented in the first sealing groove; the sealing gasket forming a seal between the housing and the baffle plate. 
   In other aspects, methods of constructing, installing, and servicing includes fluids filters of the type described. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of a filter assembly secured to a filter head, constructed according to principles of this disclosure; 
       FIG. 2  is a cross-sectional view of the filter assembly taken along the line  2 — 2  of  FIG. 1 , the filter assembly including a filter element oriented within a can or housing; 
       FIG. 3  is an enlarged view of a portion of the cross-sectional view depicted in  FIG. 2 ; 
       FIG. 4  is a perspective view of the baffle plate utilized in the filter assembly of  FIGS. 1-3 ; 
       FIG. 5  is a side elevational view of a system incorporating the filter assembly of  FIGS. 1-3 ; and 
       FIG. 6  is an enlarged cross-sectional view of a section of a prior art filter assembly. 
   

   DETAILED DESCRIPTION 
   A. Overall Assembly; Systems of Use 
   Referring first to  FIG. 1 , there is illustrated a fluid filter assembly  10 . Filter assembly  10  is particularly adapted for filtration of liquid, for example oil, as for example in a hydrostatic transmission or other hydraulic system. The filter assembly  10  includes a filter cartridge or element  12  ( FIG. 2 ) operably oriented in a can or housing  14 . The filter assembly  10  is operably mounted to a filter block or filter head  16 , typically by screwing the filter assembly  10  onto the filter head  16  by internal threads on the filter assembly  10 . 
   The filter assembly  10  is utilized in a filtering system  18 . The filtering system  18  includes a supply  20  for supplying dirty fluid to the filter assembly  10  through an inlet  22  of the filter head  16 . The fluid enters and is filtered or cleaned by the filter element  12 . The cleaned fluid exits the filter head  16  at an outlet  24  and is carried away by pipe  26 . 
   In reference now to  FIG. 5 , one application for the filter assembly  10  is to remove particulate matter from hydraulic fluid that is used in a vehicle  28 . In  FIG. 5 , the vehicle  28  depicted is a tractor  30 . An example of a tractor is an agricultural tractor that has a hydrostatic transmission and a hydraulic system, both of which require a filter. The hydraulic system can be used for a variety of purposes including raising and lowering farm implements such as plows. A hydraulic system can also be used to raise and lower earth moving equipment such as blades, buckets, backhoes, and scrapers. Other applications for the filter assembly  10  include other farm equipment, construction equipment, skidders, loaders, off-road vehicles, over-the-highway trucks, automobiles, industrial machines, and other devices that require the filtering of fluids. Additionally, the filter assembly  10  can be used to remove foreign matter from a variety of different fluids. Examples of liquid fluids include other hydraulic fluids, engine lubrication oil, diesel fuel, gasoline, engine coolant, automatic transmission fluid and others. 
   B. Some Problems With Existing Filter Assemblies, FIG.  6   
   Attention is next directed to  FIG. 6  which depicts a portion of a prior art filter assembly  200 . In the filter assembly  200 , there is a filter element  202  held within an outer can or housing  204 . The filter element  202  includes filter media  206  potted within an end cap  208 . The end cap  208  includes an opening  210 , which circumscribes a portion of a baffle plate  212 . The baffle plate  212  is secured across an open end of the housing  204 . The baffle plate  212  has an edge  214  that provides a mechanical interlock between the baffle plate  212  and the housing  204 . The edge  214  forms the outer circumferential surface and outer periphery of the baffle plate  212 . As such, the edge  214  is an outer annular surface. The edge  214  includes a groove  216  that holds a sealing gasket  218  therein to form a seal  220  between the baffle plate  212  and the housing  204 . The housing  204  includes a fold  222  that engages a top, exterior surface  224  of the baffle plate  212  to help securely lock the baffle plate  212  and the housing  204  together. 
   The prior art filter assembly  200  can introduce certain problems. For example, the baffle plate  212  is die cast. The casting is then threaded to form threads  226  on an inside diameter  228  of the baffle plate  212 . The outside diameter along edge  214  is machined to clean up the casting gates and overflows and the seal groove  216  is machined into the circumference. 
   Due to the depth of the groove  216  and the location of the groove  216  along the edge perimeter  214 , the baffle plate  212  should be vacuum impregnated with a material, such as Loctite, to seal any porosity in the casting that has been exposed by the machining operation. The sealing gasket  218 , usually a lathe-cut sealing gasket, is then placed into the groove  216 . This gasket  218  has double chamfers and lubrication so that the baffle plate  212  can be pressed into the open end of the housing  204 . Insufficient lubrication can cause the sealing gasket  218  to roll, or otherwise not be installed properly and result in a defective product. 
   After the sealing gasket  218  is installed and the element  202  is placed on the baffle plate  212 , the entire assembly (element  202  and baffle plate  212 ) is pressed into the housing  204  and the filter is seamed using a single fold seam method to form fold  222 . After painting (if desired), a molded O-ring face seal  230  is inserted into a face seal groove  232  on the top exterior surface  224  of the baffle plate  212 . 
   C. Improved Filter Assembly  10 , FIGS.  1 - 5   
   The filter assembly  10  of  FIGS. 1-5  was designed to address problems of the prior art filter assembly  200 . For example, it was recognized that if the sealing groove  216  were moved from the circumferential edge  214  to the top exterior surface  224  (the face) then the sealing gasket will be located in a groove that is cast into the face of the baffle plate instead of machined into the perimeter of it. As a result, machining time is reduced, the porosity that is exposed is negligible, and the requirement for impregnation of material (such as Loctite) is eliminated. In addition, in the filter assembly  10  of  FIGS. 1-5 , the sealing gasket does not need to have double chamfers, which results in cost savings. Further, when manufacturing new filter assembly  10 , the sealing gasket is compressed by the seaming operation and does not have to be pressed into the housing. In the prior art filter assembly  200 , pressing the baffle plate  212  with the sealing gasket  218  into the radial edge  214  requires a significant mount of force, and the sealing gasket  218  could roll, causing scrap and rework. Details of the improved filter assembly  10  are discussed below. 
   In reference now to  FIG. 2 , the filter assembly  10  includes the filter element  12  operably oriented within the housing  14 . The filter housing  14  has an interior volume  32  designed to accept the filter element  12  therein. The filter housing  14  generally has an open first end  34  and a closed second end  36 . Preferably, the housing  14  is of generally thin-walled construction having sufficient rigidity to withstand the pressure experienced during typical filtering operations. Housing  14  is typically metal, plastic, or other suitable metal; if housing  14  is metal, it is typically formed by stamping or drawing from the metal. 
   The filter element  12  is located inside the interior volume  32 . The filter element  12  includes a filtering material  38  for removing contaminants, such as particulate, from the fluid being filtered. Filtering material  38  extends from, and is potted within, a first end cap  40  and a second end cap  42 . Filtering material  38  defines an open interior volume  44 . Typically, the filtering material  38  is material such as cellulous, paper, non-woven material, synthetic material, and the like. The filter material  38  may be treated or coated to improve its filtering capabilities. 
   In the one shown, the filter material  38  includes filter media  46  that is generally a pleated, porous material, such as paper. A perforated tubular inner liner  48  can be included in the filter element  12 . The inner liner  48  is surrounded by an extension of the filter media  46  and typically extends between the first and second end caps  40 ,  42 . 
   The first end cap  40  is an open end cap and includes an opening  50  therein. The opening  50  receives, circumscribes, and surrounds a portion of a baffle plate  52 . The baffle plate  52  is secured across the open end  34  of the housing  14 . The second end cap  42  is a closed end cap that extends across and covers the end  21  of the filtering material  38  such that there cannot be access to the open interior volume  44  at end  54  of the filter element  12 . 
   The baffle plate  52  conveys filtered liquid from the filter assembly  10  and provides a barrier that prevents the bypass of unfiltered liquid around the filtering material  38 . The baffle plate  52  includes an outer, peripheral edge  56 , that forms an outer circumferential wall  58  of the baffle plate  52 . The wall  58  is also the outer radial surface of the baffle plate  52 . The baffle plate  52  also includes axially directed surfaces  60 ,  62 , which also correspond to a top end surface  64  and a bottom end surface  66 . The top end surface  64  corresponds to a top face  68 . The face  68  is generally in a plane that is orthogonal to the outer circumferential wall  58 . 
   The baffle plate  52  includes a hub  70 , in particular, a central axially extending hub that is interconnected by a plurality of radial webs or ribs  72  with a generally circular outer rim  74 . The hub  70  defines a central opening  76 , extending through the baffle plate  52  and terminating inside the filter element  12 , in particular, inside the inner liner  48 . Fluid passages  78  defined by the ribs  72  and the surrounding hub  70  allow liquid to flow therethrough and into the interior volume  32  of the filter housing  14 . 
   Threads  80  are provided on the internal surface of the hub  70  for connecting the filter assembly  10  to the filter head  16  (FIG.  1 ). The hub  70  preferably extends below the ribs  72  and into the upper end of the filter element  12 . 
   In the embodiment shown in  FIG. 2 , the filter element  12  is secured to the baffle plate  52  by direct connection or “potting” of the first end cap  40  to a neck  82  of the hub  70 . This method of assembling a filter assembly is described further in commonly assigned U.S. Pat. No. 6,345,721, incorporated by reference herein. 
   Note that the baffle plate  52  has a smooth, continuous, uninterrupted periphery  56  for its outer wall  58 . The outer wall  58  does not have any grooves (i.e., it is “groove-free”) or any other seats for holding sealing gaskets therein. Instead, the baffle plate  52  defines a groove  84  in the face  68 . As can be seen in  FIG. 4 , the groove  84  is a continuous circular groove recessed from the top end surface  64  to form a seat  86  for a sealing gasket  88  (FIGS.  2  and  3 ). In one embodiment, the sealing gasket  88  may be an O-ring gasket. Preferably, the sealing gasket  88  is a lathe-cut gasket  89 . The sealing gasket  88  is compressed between the baffle plate  52  and the housing  14  to form a seal  92  ( FIG. 3 ) therebetween. In  FIGS. 2 and 3 , it can be seen how the housing  14  is engaged against the baffle plate  52  continuously and uninterrupted along the edge  56  and outer wall  58  and then is bent orthogonally thereto to extend over at least a portion of the axial surface  60  of the baffle plate  52 . The bent portion  94  of the housing  14  forms seal  92  against the gasket  88 . The bent portion defines an end tip  108  (FIG.  3 ). The end tip  108  is spaced from a wall  110  that defines a second groove  96  (described below). Lining the groove and extending over it is a plurality of protrusions  87  (FIG.  4 ). Protrusions  87  help to hold the gasket  88  in place before the seaming operation (bending the housing  14  thereover). 
   By locating the sealing groove  84  in the face  68  of the baffle plate  52  instead of along the circumferential edge  56 , the gasket  88  is located in seat  86  that is cast into the face  68  of the baffle plate  52  instead of being machined into the perimeter of it (as shown in the prior art, FIG.  6 ). As a result, machining time is reduced, the porosity that is exposed is negligible, and the step of impregnating with Loctite material is eliminated. Further, the gasket  88  is compressed by the seaming operation of bending the housing  14  to form bent portion  94  against the axial surface  60  of the baffle plate  52 . This eliminates an extra step of compressing the sealing gasket  218  into the groove  216  (FIG.  6 ). 
   Before connection to the filter head  16 , there is another sealing gasket mounted within the baffle plate  52 . In particular, the baffle plate  52  includes second groove  96  to form a second seat  98  to receive a sealing gasket (not shown) therein. This sealing gasket forms a seal with the filter head  16 . 
   D. Methods 
   In operation, the filter assembly  10  works as follows: in a forward-flow operation, fluid to be cleaned enters the filter head through inlet  22 . From there, it flows through the openings  78  in the baffle plate  52  and into the open interior volume  32  of the filter housing  14 . From there, the fluid is forced to flow through the filter media  46  and into the open interior volume  44 . The fluid is prevented from bypassing flowing through the filter media  46  due to a seal  102  formed between the filter element  12  and the neck  82  of the baffle plate  52 . The seal  92  between the baffle plate  52  and the housing  14  prevents leakage to the outside. 
   From the open interior volume  44 , the cleaned fluid passes through the flow passage  81 , which is defined by the interior of the opening  76  of the baffle plate  52 . The cleaned fluid then exits the filter assembly  10  and flows through the filter head  16  and out through the outlet  24 . 
   After a period of operation, the filter media  46  will become occluded. The occluded filter media  46  will cause an increase in restriction. At such time, it will become appropriate to change and replace the filter assembly. In order to do this, the filter assembly  10  will be released from the filter head  16  by unscrewing the filter assembly  10  from the filter head  16 . This will release a seal formed between the filter head  16  and the second groove  96  of the baffle plate  52 . The old filter assembly  10  is discarded and replaced with a new filter assembly  10 . The new filter assembly  10  is screwed onto the filter head  16  and filtering can then be restarted. 
   To assemble the filter assembly  10 , the baffle plate  52  is provided. The filter element  12  is made by providing the extension of filter media  46 , inner liner  48 , and potting the two ends of the filter media  46  into the first and second end caps  40 ,  42 . Preferably, the first end cap  40  is positioned against an engagement surface  104  of the hub  70  prior to placing the filter media  46  into the end cap  40 . Adhesive potting material  106  is placed into the end cap  42 , and the filter media  46  is positioned into the end cap  42 . Next, adhesive potting material  106  is placed into the end cap  40 , and the filter media  46  is positioned in the end cap  40 . The potting adhesive  106  contacts and bonds to each of the end caps  40 ,  42 , the filter media  46 , and the engagement surface  104  of the hub  70 . Next, the filter housing  14  is placed over the element  12  having the baffle plate  52  secured thereto. The housing  14  is seamed or bent over the axial surface  60  to form bent portion  94  and to compress the gasket  88  between the bent portion  94  and the baffle plate  52  to form seal  92  therebetween.