Abstract:
A fluid filter includes a bypass valve and a pleated media surrounded by a thermoplastic frame. A fluid filter, includes a housing having an inlet and an outlet, a media disposed within the housing, a bypass valve disposed within the housing adjacent the media wherein the bypass valve includes a valve frame, a valve lid that couples to the valve frame, a valve pan that couples to the frame, and a seal door disposed between the valve lid and the valve frame. A method of filtering fluid, includes providing a bypass valve wherein the bypass valve includes a bypass valve seal door, raising the bypass valve seal door along a guide disposed on the bypass valve, passing fluid through the raised bypass valve seal door, lowering the bypass valve seal door along the guide disposed on the bypass valve and ceasing passing fluid through the bypass valve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. Provisional Patent Application entitled, FILTRATION SYSTEM WITH BYPASS VALVE FLOW CONTROL APPARATUS AND METHOD, filed Feb. 2, 2005, having a Ser. No. 60/648,702, the disclosure of which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to sump filters for powered vehicles. More specifically, the present invention concerns a transmission fluid or engine fluid filter having bypass valve.  
       BACKGROUND OF THE INVENTION  
       [0003]     In a powered vehicle having a lubricated transmission, it is desirable to filter debris (e.g., solid particles, impurities, etc.) out of the fluid in the transmission sump prior to the fluid entering the transmission pump. Known prior art filters utilize a porous filter media fluidly interposed between the sump and the pump to filter the fluid. Unfortunately, these prior art filters may be problematic because in certain conditions (e.g., cold and start-up conditions), the fluid is not adequately sucked through the filter media (e.g., the fluid is too viscous) and thus fluid is not sufficiently provided to the pump.  
         [0004]     Some prior art filters utilize a bypass valve to bypass the filter media during these conditions when bypass is desired. These prior art filter bypass valves however, are problematic in that they are costly to construct, unreliable, and ineffective in providing sufficient fluid to the pump during bypass conditions. They are also limited in the size and geometry of the valve.  
         [0005]     In response to industry demand, transmission and engine manufacturers continue to optimize the size of their transmissions and engines. Accordingly, transmission and engine manufacturers have required smaller components from their suppliers. The imposition of smaller spatial constraints has introduced a number of challenges to suppliers of transmission and engine components, particularly in the area of filtration.  
         [0006]     In many cases, spatial constraints have reduced the available footprint for a powertrain filter. The reduced filter footprint has reduced the available filter media surface area inside the filter. In some cases, the reduced surface area provided by conventional filter media and filter designs has introduced a number of problems including maintaining a low pressure differential across the filter during cold start-up as well as during high temperature operating conditions. Maintaining a low pressure differential across the filter during cold start facilitates quick priming of the fluid pump and during hot operation, it prevents pump cavitation.  
         [0007]     One approach to providing a low pressure differential across a filter, given a limited packaging space, has been to use less efficient filtration media. Less efficient media is less restrictive, which permits fluids to pass through the media more freely, resulting in a lower pressure differential. One drawback to this approach, however, is that using filter media that is less efficient allows larger contaminants to pass through the filter. Allowing larger contaminants to pass through the filter media is not desirable because the presence of large contaminants in the system may lead to poor shift quality or premature failure of the transmission. Another drawback to this approach is that as the filter gets smaller, the available media area also decreases, causing the velocity through the media to increase, resulting in lower filtration efficiency.  
         [0008]     Accordingly, it is desirable to provide a method and apparatus that combine the ability for thorough fluid filtration and the ability for bypass flow through the use of a bypass valve, in a cost effective, compact manner.  
       SUMMARY OF THE INVENTION  
       [0009]     The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect an apparatus is provided that in some embodiments combines the ability for thorough fluid filtration and the ability for bypass flow through the use of a bypass valve, in a cost effective, compact manner. In particular, a single unitary frame surrounds both a media, as well as a bypass valve. The bypass valve includes guides that allow for the bypass valve seal door to open and close without becoming misaligned.  
         [0010]     In accordance with one embodiment of the present invention, a bypass valve includes a frame, a lid configured to couple to the frame, a pan configured to couple to the frame, and a seal door disposed between the lid and the frame, moveable between an open position and a closed position.  
         [0011]     In accordance with another embodiment of the present invention, a fluid filter includes a housing having an inlet and an outlet, a media disposed within the housing, a bypass valve disposed within the housing adjacent the media wherein the bypass valve includes a valve frame, a valve lid configured to couple to the valve frame, a valve pan configured to couple to the frame, and a seal door disposed between the valve lid and the valve frame, moveable between an open position and a closed position.  
         [0012]     In accordance with yet another embodiment of the present invention, a media pack includes a fibrous sheet, and a frame surrounding the fibrous sheet.  
         [0013]     In accordance with still another embodiment of the present invention, a method of filtering fluid includes providing a bypass valve wherein the bypass valve includes a bypass valve seal door, opening the bypass valve seal door along a guide disposed on the bypass valve to permit fluid through the raised bypass valve seal door, and closing the bypass valve seal door along the guide disposed on the bypass valve to prevent passing fluid through the bypass valve.  
         [0014]     In accordance with yet another embodiment of the present invention, a system of filtering fluid includes a filtering means, a filter supporting means surrounding the filtering means, a housing means surrounding the filtering means and the filter supporting means, and a bypass flow means includes a bypass flow supporting means, a first bypass housing means disposed adjacent the bypass flow supporting means, a second bypass housing means disposed adjacent the bypass flow supporting means, a sealing means disposed between the first and the second bypass housing means, moveable between an open position and a closed position, and a guiding means for guiding the sealing means.  
         [0015]     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.  
         [0016]     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.  
         [0017]     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a perspective view of the filter assembly according to an embodiment of the present invention.  
         [0019]      FIG. 2  is a longitudinal cross sectional view of the filter assembly according to a preferred embodiment of the invention.  
         [0020]      FIG. 3  is a transverse cross sectional view illustrating the filter assembly according to a preferred embodiment of the invention.  
         [0021]      FIG. 4  is a perspective view of a media pack according to a preferred embodiment of the present invention.  
         [0022]      FIG. 5  is a perspective view of a bypass valve.  
         [0023]      FIG. 6  is an exploded perspective view of the media pack and the bypass valve as shown in  FIGS. 1, 2  and  3 .  
         [0024]      FIG. 7  is an exploded side view of the media pack and the bypass valve as per another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides a filter assembly having a bypass valve and pleated media, enclosed in a filter housing. The bypass valve frame and pleated media frame may be formed of a unitary construction. The bypass valve includes guides that allow for the bypass valve seal door to open and close without becoming misaligned.  
         [0026]     An additional preferred embodiment of the present invention includes the ability to use the pleated media-bypass valve assembly in any type of fluid housing, including all plastic filters and composite filters that are formed with both a metal cover and a plastic cover. Thus, the presently claimed invention has broad application for fluid filtration and may be used in engines, transmission or other machinery.  
         [0027]     Yet another preferred embodiment of the present invention includes molding a plastic or thermoplastic resin over the pleated media to provide the external structure for the media. The pleated media may be made of any type of material capable of filtering fluids. Molding the plastic around the media allows for additional structure to be added to the media, such as the bypass valve. The filter assembly also includes supports or pinch points formed adjacent the media from the thermoplastic resin to provide for spacing between the media and the filter housing. Such spacing facilitates fluid flow. The supports may be formed on either side of the media, extending toward both the upper and lower covers of the filter housing.  
         [0028]     Forming the resin over the media also allows for a compact and cost effective way of creating additional beneficial structure and function to the filter assembly such as a bypass valve. Being able to form the media, the pinch point supports and the bypass valve in a more efficient manner reduces cycle time and allows for a much better filter at a lower cost.  
         [0029]      FIG. 1  is a perspective view of the filter assembly  10  according to an embodiment of the present invention. The filter assembly  10  has a cover  12  and a pan  14  sealed together at the edges  16  of cover  12  and pan  14 . The cover  12  and pan  14  may be sealed using a plurality of fasteners  18  or are sealed in a variety of other ways. The filter assembly  10  also has an outlet  20  extending longitudinally from the cover  12 .  
         [0030]      FIG. 2  is a longitudinal cross sectional view of the filter assembly  10  according to a preferred embodiment of the invention. A bypass valve assembly  22  is disposed at a distal end from the outlet  20 . Adjacent the bypass valve assembly  22 , proximal to the outlet  20 , is disposed a pleat pack or a media pack  24 . The media pack  24  includes a frame  26  and media  28 . The frame  26  may be formed of any suitable material, preferably a thermoplastic resin. The media  28  may be formed of any suitable material, preferably a fibrous material. The filter assembly  10  further includes spacers  30  formed on the pan  14  to provide a space between the pan  14  and the floor of fluid container in which the filter assembly  10  is placed. For example, the fluid container may be a transmission pan, an engine pan or any such machinery or fluid application requiring fluid filtration. Lastly, an inlet  32  is disposed at a distal end from the outlet  20 , formed on the pan  14 .  
         [0031]      FIG. 2  also illustrates the various pinch points  34  or supports  36  molded onto the frame  26  to provide integrity to the filter housing cover  12 . It can also be seen that the pinch points  34  create a space for the fluid flow. In addition, this figure also shows the bypass valve  22  with the placement guides  44  adjacent the shafts or cylinders, formed on the bypass valve cage.  
         [0032]      FIG. 3  is a transverse cross sectional view illustrating the filter assembly  10  according to a preferred embodiment of the invention. The media pack  24  is shown with the frame  26 , media  28  and a plurality of pinch points  34  on either side of the frame  26 .  FIG. 3  also illustrates the pleated nature of the media  28  and the molded structure that forms the pinch points  34 . It can be seen here as well, that the pinch points  34  serve to provide greater strength for the filter housing walls and create a space for the fluid flow. Throughout the media pack  24 , the resin is molded adjacent the media  28 .  
         [0033]      FIG. 4  shows the filter insert including the pleated media  28 , the pinch points  34 , the external structure of the molded resin adjacent the media  28  and the bypass valve  22 . It can be seen that the media  28  is arranged in a longitudinal fashion and that there are several areas across the media  28  where the frame  26  supports the media  28 . Although four such supports  36  are illustrated, any number of supports  36  may be implemented. Pinch points  34  may be arranged on the supports  36 .  
         [0034]     The pleated media  28  in a preferred embodiment, has pleats running longitudinally to the filter housing, allowing for fewer pleats but with longer lengths. This configuration increases the total surface area available for filtration. This pleat direction also allows the fluid to flow well. In addition, this longitudinal pleating allows for more efficiency in the packaging of the pleated media. This reduces cost in reducing the packaging material required and costs associated with shipping.  
         [0035]     Supports  36  serve several functions. They provide support to the housing in that the housing is kept rigid. The pinch points  34  also greatly increase strength in the housing. Further, they decrease detrimental deformation of the cover  12  or pan  14  under load, allowing larger filters with thinner housing walls which leads to overall cost reduction of the entire filter assembly. Moreover, these supports  36  and pinch points  34  allow for a space between the media  28  and the cover  12  or pan  14  through which the fluid may also flow freely. Furthermore, during bypass filtration, the fluid may flow freely through the space created by the supports, between the media and the housing cover especially because under cold-start conditions, the fluid is more viscous.  
         [0036]      FIG. 5  is a perspective view of the bypass valve  22  as shown in  FIG. 4 . The bypass valve  22  has a valve lid  38  and a valve pan  40 . Both the valve lid  38  and the valve pan  40  are similar in structure and may be mirror images of each other. They both have an open lattice structure like a cage, to permit fluid to easily pass through. The valve pan  40  may have a mesh screen (not shown) attached to it, to provide some filtration of the fluid being bypassed from the media  28 . This mesh screen would provide a coarse filtration of the fluid to prevent large particles from damaging the transmission, engine or other machinery, in which this filter assembly  10  may be placed.  
         [0037]     The bypass valve  22  also has a valve frame  42  formed on the frame  26 . The valve frame  42  also has an open lattice structure and supports a guide  44 . Here, two guides  44  are shown, however any number of guides may be implemented. The guides  44 , formed of unitary construction with the valve frame  42 , extend vertically upward. The guides  44  may be of any shape, for example, of a cylindrical nature, and may be hollow. Although shown here formed on the valve frame  42 , the guides  44  may be formed on the valve pan  40 . If the guides  44  are formed on the valve pan  40 , a valve frame  42  may not be used.  
         [0038]     The valve lid  38  and valve pan  40  are attached to the valve frame  42  by any means known in the art. They may be made of thermoplastic, metal, or any suitable material. They may also be of any desired configuration. Often bypass valves have been circular to prevent misalignment. Misalignment may occur when the valve door is repeatedly raised and lowered to permit bypass flow. When returning to close off the bypass flow, misalignment of a valve door may occur. Such misalignment is detrimental to fluid filtration as fluid may continue to proceed through the bypass valve even when the filter is operating in such a manner as to not require bypass flow. Such flow will contain unintended impurities because bypass flows are not as thoroughly filtered as fluid flow through media. Here, however, the shape may be of any desired configuration because guides  44  are used to prevent misalignment. The valve lid  38  and valve pan  40  are formed in a cage-like manner with an open lattice structure, allowing viscous fluid to flow more freely through the bypass valve  22 . The bypass valve  22  structure also includes several shafts or cylinders that serve to prevent misalignment.  
         [0039]     This ability to keep the valve appropriately aligned at all times allows for a variety of shapes and sizes and removes any restraints placed by capacity requirements for the fluid flow. This non-circular design of the bypass valve  22  allows for the ability to maximize the bypass fluid flow. It also allows for various configurations in designing such a filter assembly  10  to include both a pleated media  28  and a bypass valve  22 .  
         [0040]      FIG. 6  is an exploded perspective view of the entire assembly. The figure illustrates the filter lip seal  46  that couples with the filter outlet  20 . The filter outlet  20  is formed on the cover  12 . The media pack  24  includes the pleated media  28  and the pinch points  34  formed from the molded frame  26 . The bypass valve  22  contains a valve lid  38  that rests on the frame  26 .  
         [0041]     Below the valve lid  38  is disposed a seal door  48 . The seal door  48  contains recessions  50  that accommodate and receive the guides  44 . The recessions  50  are shaped to accept the guides  44  and rest atop the guides  44 . The seal door  48  is raised to permit fluid to pass through the bypass valve  22 . As the seal door  48  is raised, recessions  50  ride along the guides  44  and move upward. When bypass flow is no longer needed, the seal door  48  lowers back down to close off the bypass valve  22 . When the seal door  48  lowers back down toward the valve frame  42 , the recessions  50  maintain contact with the guides  44  and ride the guides  44  back down. This relationship between the guides  44  and the recessions  50  prevents misalignment of the seal door  48  as it is repeatedly raised and lowered.  
         [0042]     A valve pan  40  is disposed below the guides  44 . The valve pan  40  may have a mesh screen (not shown) attached for coarsely filtering the bypass flow. The assembly also contains a filter pan  14  with the fluid inlet  32 .  
         [0043]      FIG. 7  is an exploded side view of the media pack  24  and the bypass valve  22  as per another embodiment of the present invention. In this embodiment, the seal door has guides  52 , rather than recessions  50 . Correspondingly, valve frame  42  will have recessions (not shown) to accommodate and receive the guides  52 .  
         [0044]     Although an example of the filter assembly is shown using the media pack along with a bypass valve for a transmission filter, it will be appreciated that other types of pleated configurations along with bypass valves can be used and that various other configurations of pleated and non-pleated media may be used to create the molded filter assembly. It may also be possible to form a variety of filters with various configurations of the bypass valve. Also, although the device is useful in the automotive industry, it can be used in any type of system requiring fluid filtration, including engines and engine filters.  
         [0045]     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended disclosure to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.