OPTIONAL BUBBLE BREAKER

[0001] This application claims priority to provisional U.S. Patent application 61/242,622, titled FILTER WITH OVAL OR FLAT-SIDES DESIGN, CCM/CLEANLINES MEDIA GRADE, AND BUBBLE BREAKER, filed September 15, 2009, the entire disclosure of which is incorporated herein.

[0002] This application also claims priority to provisional U.S. Patent application 61/242,615, titled SPACE REDUCING FILTER WITH OVAL OR ROUND INNER DIAMETER, COALESCER, CCM/CLEANLINESS MEDIA GRADE, AND BUBBLE BREAKER, also filed September 15, 2009, the entire disclosure of which is also incorporated herein.

BACKGROUND OF THE INVENTION

[0003] Field of the Invention

[0004] The present invention concerns a filter, for fuel or other fluids, such as oils or other liquids, or even gases, that is preferably oval or flat-sided in cross- sectional configuration. A design according to this invention permits different functions to be included in an oval, flat-sided, or even round filter design, although an oval design is preferable to a flat design, as it more readily avoids collapse and makes it possible to integrate additional parts for cleanliness, water drainage for the clean side, and so on. [0005] Description of Related Art

[0006] A brief discussion of certain filter systems for automotive or other applications utilizing multiple full flow and bypass filter arrangements is set forth in commonly assigned, co-pending U.S. Patent application serial no. 12/467,423, filed May 18, 2009, titled Full Flow Liquid Filter with Integral Bypass Filtration. That discussion is partially reiterated here.

[0007] Filter systems for automotive or other applications commonly utilize one of two full flow filter and bypass filter configurations. One such configuration is an arrangement having two separate filtering systems, with a full flow system, which may include more than one filter, depending on flow requirements, and a bypass filter system, which processes only a small percentage of the full fluid volume. In such a configuration, an in-line, series approach is often utilized, with a full flow filter provided downstream of a bypass filter. These systems typically introduce additional costs and components for the automotive assembler and service industry to handle and manage. Vehicle weight is increased as well. U.S. Patent application publication 2008/0078716 to Farmer discloses one such in-line, series approach to filtering.

[0008] Evolutions of this configuration include systems having filters with full flow and bypass media stacked upon each other in the same filter housing. Examples of filters having stacked media include apparatuses disclosed by U.S. Patent application publication 2005/0252838 to Fisher and U.S. Patents 5,447,627 to Loafman et al., 6,319,402 to Schwandt et al., and 6,350,379 to Roll et al.

[0009] Further developments have provided increased filtering capacity in the same or smaller footprint, while also offering high efficiency bypass filtration to "polish" the fluid system and provide integral soot filtration, by fitting bypass filters concentrically within full flow filters. U.S. Patents 6,666,968 to Smith et al., 6,787,033 to Beard et al., 7,014,761 to Merritt et al., and 7,090,773 to Meddock et al. provide examples of such developments.

SUMMARY OF THE INVENTION

[0010] A fluid filter according to one aspect of the invention is designed to be receivable in a filter container that is closable by a cover. The filter itself includes both an annular main filter element through which fluid to be filtered can pass radially to undergo primary filtration and a supplemental filter element to which fluid discharged from the main filter element passes to provide supplemental filtration additional to the primary filtration. The main filter element, the supplemental filter element, or both may be oblong or circular in cross section. At least one of a pair of end caps disposed on opposed ends of the main filter element carries the supplemental filter element as well as one end of the main filter element. That end cap may or may not be permanently secured to the one filter element end. [0011] The fluid filter may additionally include a coalescer, which may surround the main filter element exterior, can be used to pre-process fluid to be filtered before that fluid undergoes the primary filtration. A frame, which may be securable to and detachable from the filter container cover, can be provided to mount both the supplemental filter element and the coalescer.

[0012] The supplemental filter can be configure to protrude from one of the end caps on which it is carried into a cavity defined at a downstream side of the main filter element. Optionally, the filter may include an arrangement by which bubbles in the fluid to be filtered are broken up and dissolved. Such a bubble breaker arrangement may be mounted in an appropriate location on one of the end caps.

[0013] According to another aspect of the invention, a fuel filter, such as a filter for filtering gasoline or diesel fuel to be supplied to an internal combustion engine, includes an annular main filter element through which fluid to be filtered can pass radially, and a supplemental fluid processing element disposed within the main filter element to which fluid discharged from the main filter element passes. The filter also has end caps, between which opposite ends of both the main filter element and the supplemental fluid processing element are disposed, and to which the opposite ends of both the main filter element and the supplemental fluid processing element are secured. Fluid is discharged from a central volume of the filter through one of the end caps. [0014] The supplemental fluid processing element may be a supplemental cleanliness medium element or a coalescer to increase water droplet size. In either case, in the particular configurations disclosed, the supplemental fluid processing element includes a frame and multiple individual elements, for filtering or coalescing operations, retained by the frame. To avoid water contamination of fluid discharged from the filter, a hydrophobic medium may be disposed within the supplemental fluid processing element. Such a hydrophobic medium may surround the central volume circumferentially or bound the central volume at one of its ends.

[0015] The fluid filter can further include an additional fluid processing element that may also surround the main filter to pre-process fluid supplied to the main filter. In one preferred arrangement, this additional fluid processing element is formed by another frame and multiple individual coalescer elements retained by the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic perspective view of a typical annular, preferably oval or flat (flattened) filter element.

[0017] Figure 2 is a schematic perspective view of an annular, preferably flattened filter element according to one embodiment of the invention. [0018] Figure 3 is a schematic perspective view of an annular filter element according to another embodiment of the invention.

[0019] Figure 4 is a schematic perspective view of an annular filter element according to yet another embodiment of the invention.

[0020] Figure 5A is a schematic sectional view of a filtering system in which a filter element is glued or otherwise affixed to a filter element container cover.

[0021] Figure 5B is a schematic sectional view similar to Figure 5A but of a configuration in which the filter element is not affixed to the filter element container cover so that the filter itself is serviceable.

[0022] Figure 6A is a view showing one configuration of the union between the top of the filter element and the cover according to Figure 5A.

[0023] Figure 6B is a view showing the configuration of the cover according to Figure 5B.

[0024] Figure 7 is an exploded view showing the snap union between the top of a combined coalescer and component cleanliness management (CCM), or cleanliness, medium structure, and a housing cover. [0025] Figure 8 is a sectional view of a combined coalescer and CCM medium structure showing a sealing lip.

[0026] Figure 9 is a sectional view similar to that provided by Figure 8 but in which the combined coalescer and CCM medium structure is provided with a bubble breaker.

[0027] Figure 10 is a external perspective view from above another arrangement that operates similarly to that shown in Figure 9.

[0028] Figure 11 is an external perspective view from below the arrangement shown in Figure 10.

[0029] Figure 12 is a cut-away sectional view of the arrangement shown in Figure 10 as seen along line 12-12.

[0030] Figure 13 is an enlarged view of part of the arrangement shown in Figure 12.

[0031] Figure 14 is a perspective view of the inner jacket and media arrangement of Figure 12.

[0032] Figure 15 is a view illustrating a snap union I-jacket with a bottom end cap. [0033] Figure 16 is a perspective view from above the bubble breaker of Figure 10.

[0034] Figure 17 is an enlarged, part sectional view along line 17-17 of Figure 16.

[0035] Figure 18 is a schematic sectional view of another oval or flattened annular main filter element with an associated supplemental cleanliness medium filter element.

[0036] Figure 19 is a schematic sectional view of a configuration similar to that of Figure 18, but showing a coalescer that surrounds the main filter element, a sealing lip, and a bubble breaker.

[0037] Figure 20 is a sectional view of a compact three-stage design according to the invention.

[0038] Figure 21 is a sectional view of another compact three-stage design.

[0039] Figure 22 is a sectional view of a compact five-stage design including a bubble breaker. [0040] Figure 23 is a sectional view of a main filter element with a coalescer and an internal bubble breaker associated therewith.

DETAILED DESCRIPTION OF THE INVENTION

[0041] Figure 1 is a schematic perspective view of an oval or flat annular filter element without any "component cleanliness management (CCM)," or supplemental cleanliness medium filter element associated therewith. Fuel or other fluid traverses the filter element shown in Figure 1 radially, and, as such, is filtered by the annular main filter element 20, the material 26 of which may be pleated in typical fashion. In its simplest configuration, the material is glued or bonded in some other way to oval, open-centered or ring-like end caps 22 and 24, which are disposed at axially opposed open ends of the main filter element 20. An uppermost open end 28 of the element 20 is visible in Figure 1. The annular main filter element 20 provides fine particle filtration to fluid passing radially through the material 26 in a conventional manner.

[0042] Figure 2 is a schematic perspective view of an oval or flattened filter F according to a first embodiment of the invention having an annular main filter element 30. As with the conventional element illustrated in Figure 1, fuel or other fluid traverses the filter element 30 radially, passing through the material 36, which, again, may be pleated. Oval, open-centered or ring-like end caps 32 and 34 are disposed at axially opposed ends of the main filter element 30. [0043] The main filter element 30 includes a pair of open axial ends similar to those present in the conventional configuration shown in Figure 1. The uppermost open end 38 of the filter element 30 is visible in Figure 2. Also visible in Figure 2 is the flat outer surface of a supplemental or secondary cleanliness medium filter element 39, which is disposed at least partly within the open end 38 of the main filter element 30. Such supplemental cleanliness medium filter elements will hereafter be referred to simply as "supplemental filter elements." The main filter element 30, which is the same as the element 20 shown in Figure 1, will not completely filter all particles out of the fluid being filtered. The supplemental filter element 39 has a finer pore size than that of the main filter element 30, or is otherwise configured to provide filtering beyond that provided by the main filter element 30, and operates to supply additional filtration of fluid that has already passed through the main filter element. By way of example only, and depending on customer requirements, the main filter element 30 may operate at 86% efficiency, while the supplemental filter element 39 operates at 95% efficiency. The arrangement illustrated in Figure 2, and the arrangements shown in Figures 3-9 as well, may be referred to as "sky" designs, since supplemental cleanliness mediums are disposed at "upper" ends of the combined main filter/cleanliness medium filters and main filter/cleanliness medium filter/coalescer arrangements shown.

[0044] Figure 3 is a schematic perspective view of another oval or flattened filter F having an annular main filter element 40. Fuel or another fluid travels relative to the filter element 40 along a path indicated by the various arrows. As in the embodiment shown in Figure 2, this fluid traverses the filter element 40 radially, passing in the direction of an arrow 41 through the material 46, which, again, may be pleated. Oval, open-centered or ring-like end caps 42 and 44 are disposed at axially opposed ends of the main filter element 40.

[0045] The main filter F, or, more precisely, the main filter element 40, includes a pair of open axial ends; an uppermost open end 48 of the filter element 40 is indicated in Figure 3. Also visible in Figure 3 is the flat outer surface of a supplemental filter element 49, which is disposed at least partly within the open end 48 of the main filter element 40. As in the embodiment shown in Figure 2, the supplemental filter element 49 has a finer pore size than that of the main filter element 40, or is otherwise configured to provide filtering beyond that provided by the main filter element 40, and operates to provide additional filtration of fluid that has already passed through the main filter element 40.

[0046] In this configuration, water-contaminated or dirty fuel received from a fuel tank (not shown) passes in the direction of an arrow 45 through a coalescer 43. This pre-filtered fuel then passes, as schematically indicated by the arrows 47 and 41, through the main filter material 46. The coalescer 43 is formed by an oval or oblong ring extending laterally with respect to a longitudinal axis of the main filter element 40. The coalescer 43 serves in a known manner to pre-filter or pre-process fuel arriving from the fuel tank by increasing water droplet size, facilitating water repellency of hydrophobic media included in the main filter. Typical coalescers are cellulose based or synthetic. [0047] Water-contaminated or dirty fuel supplied in the direction of the arrow 45 from the fuel tank is processed sequentially as it travels in the directions indicated by the arrows, passing through the coalescer 43, the main filter element 40, and then the supplemental filter element 49 of the overall arrangement. As Figure 3 shows, clean, fully processed, filtered fuel exits the overall filter F in the direction of an arrow 50, and can then be supplied to an engine (not shown).

[0048] Figure 4 is a schematic perspective view of another oval or flattened filter F with an oval or flattened annular main filter element 60. The flat surface of a supplemental filter element 69 is visible at one end of the filter F, and a coalescer 63, formed by a jacket extending parallel to a longitudinal axis of the main filter element 60, is mounted on the circumferential exterior of the main filter element 60. A cage or frame 65 may be used to retain the coalescer 63 on the circumferential exterior of the main filter element. The coalescer 63 may be either a single solid element, with the cage or frame 65 disposed around it, or composed of multiple individual coalescer elements received within openings defined by the cage or frame 65. Again, fuel from a fuel tank, which may initially be water-contaminated or dirty, travels in directions indicated by arrows 66, 67, and 61, sequentially passing through the coalescer 63, the main filter element 60, and the supplemental filter element 69 of the overall arrangement. Clean, fully processed, filtered fuel exits the overall filter F in the direction of an arrow 70, and can then be supplied to the engine. [0049] Figure 5A is a schematic sectional view of part of a filtering system in which a filter according to the invention, such as the filter F shown in Figure 2, Figure 3, or Figure 4, is glued or otherwise affixed to the underside of a filter element container cover 80. The cover 80 is securable to and removable from a container body 82, and thus serves to close off the container body 82, in which a filtering process such as that described above in connection with Figures 2-4 occurs. Snaps, threads or other such features may be used to interconnect the cover 80 and the container body 82. Supply lines 90, by which water- contaminated, dirty fuel or other fluid may be supplied for filtering, are shown in schematic fashion as opening to the interior of the overall container formed by the cover 80 and the container body 82. Also illustrated schematically in Figure 5A is a discharge line orifice or connection 92. It will be understood that fuel or another fluid to be filtered enters the container body 82, for example through one or more supply lines 90, passes radially through the main filter element 30, 40, or 60, passes through the supplemental filter element 39, 49, or 69, and is discharged from the container 82 through the discharge line orifice or connection 92.

[0050] The filter F may be affixed in any appropriate manner to the cover 80; depending on the material used for the cover 80, the filter F may be secured to the cover 80 by use of a chemical bonding solution, such as LOCTITE, by polyvinyl chloride (PVC) or polyurethane bonding techniques, by infrared or ultrasonic welding, or by way of appropriate extrusion techniques. When the filter F of the system shown in Figure 5A becomes dirty, the cover 80 and filter F are both removed together and replaced.

[0051] Figure 5B is a schematic sectional view similar to Figure 5A but of a configuration in which the filter F is not affixed to the filter element container cover 84. When the filter F of the system shown in Figure 5B becomes dirty, only the filter F needs to be replaced. The filter element container cover 84 is reusable.

[0052] A more detailed view of one configuration of a union between the top of a filter F and a cover 80 in an arrangement such as that shown in Figure 5A is provided by Figure 6A. For the purposes of illustration and this discussion only, it will be presumed that the filter F shown in Figures 5A and 6A has the configuration of the filter F shown in Figure 2, and thus includes a main filter element 30 and a supplemental filter element 39 disposed at least partly within an open end of the main filter element 30. The supplemental filter element 39 includes an oval, central area surrounded by an upstanding, recurved, oval mounting flange 90 by which the supplemental filter element 39 is securable within the main filter element open end. The cover 80 shown in Figure 6A has a closed center 98 instead of the discharge line orifice or connection 92 of Figure 5A; the closed center 98 may be removed or punctured or otherwise penetrated to form an orifice for connection to the discharge line. An external thread or flange 96 may be disposed on the circumferential exterior of the cover 80 to cooperate with an internal thread or recess at the open end of the container body 82 in order to retain the cover in place. Other connections between the cover 80 and the open end of the container body 82 are useable.

[0053] Figure 6B provides an illustration of a cover 84 in an arrangement in which a main filter element and a frame to which the filter element is secured are detachable. Again, an external thread or flange 96 may be disposed on the circumferential exterior of the cover 84 to cooperate with an internal thread or recess at the open end of the container body in order to retain the cover 84 in place. Again, other connections between the cover 84 and the container body are useable. The arrangement shown in Figure 6b is also shown in the exploded view provided by Figure 7, which schematically illustrates a plurality of individual supplemental filter elements 109 and a plurality of individual coalescer elements 103 mounted within a frame 110. The frame 110 shown has a circumferential lip 112, which is receivable within a groove or recess 116 defined on the inner circumference of a container cover 114 that is similar to the cover 84 shown in Figure 6b. By snapping the lip 112 into the recess 116, the frame 110, including elements mounted therein that combine to provide functions of both a supplemental filter and a coalescer, is securable to and interlocks with the cover 114. The frame 110, with elements 103 and 109 secured therein, can then be placed over the exterior of the main filter element (not shown in Figure 7).

[0054] A frame 120, which is essentially the same as the frame 110 of Figure 7, is schematically shown in Figure 8 as attached, by an annular layer 122 of glue, for example, to an end of a conventional main filter element, such as the conventional main filter element 20 shown in Figure 1 and described above. By attaching the frame 120, including individual supplemental filter elements 129 and individual coalescer elements 123, to the filter element 20, it is possible to produce an overall filter element having combined main filtering, auxiliary filtering, and coalescing properties. Figure 8 also illustrates an annular lip extending around a bottom end of the combined coalescer and cleanliness medium structure to provide a seal between the overall jacket 127 and the housing. More specifically, the frame 120 illustrated in Figure 8 has a circumferential lip 128 of plastic surrounding its open end opposite the end receiving the supplemental filter elements 129. The lip 128 is provided to produce a seal between the external housing (not shown in Figure 8), within which the jacket 127 formed by the combination of the frame 120 and the elements 123 and 129 is received, and that frame 120. The lip 128 thus facilitates fluid flow along an appropriate path.

[0055] The jacket 137 illustrated in Figure 9 is essentially the same as the jacket 127 shown in Figure 8, except that it has a schematically shown bubble breaker 140 formed or mounted on its end. The bubble breaker 140 is optional, includes an open medium, and may be integrated with the filter to dissolve or reduce sizes of air pockets or bubbles in fluid passing through the filter. Once the bubble breaker 140 has eliminated unwanted air from the fuel or other fluid, "de-bubbled" fuel or fluid is discharged back into the fluid flow. [0056] The arrangement illustrated in Figures 10-17 is similar to that shown in Figure 9, but differs in terms of placement of the supplemental filter element added to provide the additional filtering discussed above. Figure 10 is a external perspective view from above a filter F, and shows a jacket 147, including an outer frame 150 supporting a coalescer element 152. A plurality of individual coalescer elements could alternatively be used. The frame 150 shown has a circumferential lip 154 at its lower end. This lip 154 functions in the same way as the lip 128 illustrated in Figure 8 to facilitate fluid flow along an appropriate path by cooperation with an external housing (not shown). It will be understood that the extension angle of the lip 154 can be modified to adjust the degree of sealing with the interior of the external housing; as this extension angle is decreased, pressure of the lip against the housing interior decreases, and sealing decreases accordingly.

[0057] Also evident in Figure 10 are an upper end cap 156 and a bubble breaker 158 surrounding a discharge line orifice or connection 160, which is essentially the same as the discharge line orifice or connection 92 represented in Figure 5A. The corresponding view from below the filter F provided by Figure 11 shows the lowermost part of a main filter element 170, the central opening of which is closed of by a lower end cap 172. The lip 154, forming the terminus of the jacket 147, is displaced a distance 174 above the bottom of the main filter element 170. As with other main filter elements described above, the main filter element 170 may be formed of material that is pleated in typical fashion. [0058] The jacket 147, the frame 150, the coalescer element 152, the circumferential lip 154, the upper end cap 156, the bubble breaker 158, the discharge line orifice or connection 160, the main filter element 170, and the lower end cap 172 are all evident in the cut-away sectional view provided by Figure 12. Also evident in Figure 12 is an inner frame 176 used to support a supplemental filter element 178. As with the arrangements described previously, this supplemental filter element 178 serves to provide filtering beyond that provided by the main filter element 170 by way of additional filtration of fluid that has already passed through the main filter element 170. In the arrangement of Figure 12, however, the additional or supplemental filter element 178 is retained against or adjacent to the radial interior of the main filter element 170 by the inner frame 176. This is also apparent from the somewhat enlarged view provided by Figure 13.

[0059] The perspective view provided by Figure 14 shows the supplemental filter element 178 and the inner frame 176 as separated from the remainder of the arrangement illustrated in Figure 10. It will be understood that the inner frame 176 is united with the lower end cap 172 in an appropriate way such as by snap connections. One such snap connection is shown in Figure 15. Figure 15 also shows a portion of the circumferential lip 154 at the lower end of the frame 150. It will be understood from considering Figures 12 and 16 together that the supplemental filter element 178 protrudes from the lower end cap on which it is carried into the central cavity defined by the annular main filter element 170 at its downstream side. [0060] Figure 16 provides a perspective view from above the bubble breaker 158, while Figure 17 is an enlarged, part sectional view of the structure shown in Figure 16. One conceivable way to secure the bubble breaker 158 in place is to first appropriately position the bubble breaker 158 on the upper end cap 156, for example by way of a protrusion 180 on the cap 156 that cooperates with a slot 182 in the bubble breaker 158 as shown in Figure 16. The bubble breaker 158 can then be pressed into connection with the upper end cap and retained in place over the discharge line connection 160 by cooperating snap elements 184 (visible in Figure 17) on the bubble breaker and the end cap.

[0061] Air pockets or bubbles entrained in fluid supplied to the interior of a container body, such as the container body 82 shown in Figure 5A, tend to rise within the container body interior. Fluid pressure causes the bubbles to proceed into bubble inlets 186. As the fluid in which the bubbles are entrained passes into the bubble inlets 186, through filter media 188, through passages 189, and back upstream of the main filter element 170, the bubbles are broken up so that they will not adversely affect an engine or other item to which the fluid passing through the filter is supplied. An o-ring seal 190 facilitating fluid tight connection between the discharge line orifice or connection 160 and a discharge line (not shown) is retained in position by an appropriate groove 192 formed in the upper end cap 156. An appropriate flange 194 on the bubble breaker 158 can also extend over the seal 190 to assist in proper retention of the seal. [0062] In Figures 18-23 and in the following discussion, the same reference numbers or characters are used in to identify elements shown in different drawing figures when those elements have the same or essentially the same structure and operation.

[0063] A schematic sectional view of an overall filter F, including a preferably oval or flattened annular main filter element 10 with an associated "component cleanliness management (CCM)" element and appropriate end caps, is provided by Figure 18. The "CCM" element, which forms a supplemental fluid processing element, will be referred to subsequently as a supplemental cleanliness medium filter element, and is generally indicated in Figure 18 by reference number 12. When the filter F is used in a fuel filtering application for a diesel fuel or gasoline powered internal combustion engine, for example, water-contaminated or dirty fuel received from a fuel tank (not shown) passes in a substantially radial direction 18 through the main filter element 10 under pressure, and is filtered initially by the annular main filter element 10. The main filter element 10 may be formed of cellulose and glass fibers, or cellulose, glass fibers, and hydrophobic meltblown material. The main filter element 10 may additionally include an appropriate scrim.

[0064] In its simplest configuration, the material constituting the main filter element 10 is glued or bonded in some other way to a first end cap 14, which may be solid, and a second, open-centered end cap 16. The end caps 14 and 16 are disposed at axially opposed ends of the main filter element 10. The annular main filter element 10 provides fine particle filtration to fluid as it passes through the filter element 10 in the direction 18.

[0065] Although a one-piece filter medium wrapped around a support frame or some other type of supplemental cleanliness medium filter configuration is usable, the supplemental cleanliness medium filter element 12 shown in Figure 18 is defined by a frame or jacket 13 and multiple individual supplemental filter elements 20 received and retained in the frame or jacket 13. The frame or jacket 13 will be referred to subsequently as a "frame" or a "first frame." Each arrangement or design illustrated in Figures 18-23 is a "compact" arrangement or design, since the frame 13 and the filter elements 20, or a similar frame and fluid processing elements of at least one other type, are disposed centrally within and coaxial with the main filter element 10.

[0066] As illustrated in Figure 18, one axial end 30 of the frame 13 is bonded or otherwise secured, together with an end of the main filter element 10, to the first end cap 14, while another axial end 32 of the frame 13 is bonded or otherwise secured, together with another end of the main filter 10, to the second end cap 16 opposite the first end cap.

[0067] Figure 18 shows the second end cap 16 as glued or otherwise directly affixed to the underside of a partially illustrated filter container cover 17, which is securable to and removable from a filter container body (not shown) in which a filtering process occurs. Snaps, threads, or other such features may be used to interconnect the cover 17 and the container body. When the overall filter F shown in Figure 18 becomes dirty or saturated, the cover 17 and the filter F are removed together and replaced.

[0068] The main filter element 10 will not completely trap all particles in the fluid being filtered, and the elements 20 of the supplemental cleanliness medium filter element 12 have finer pores than those of the main filter element 10 to provide additional filtering. The supplemental cleanliness medium filter element 12, of course, could be configured in some other way to provide filtering beyond that provided by the main filter element.

[0069] The supplemental cleanliness medium filter element 12 accordingly operates to provide additional filtration of fluid that has already passed through the main filter element 10. By way of example only, and depending on customer requirements, the main filter element, again, may operate at 86% efficiency, while the supplemental cleanliness medium filter element operates at 95% efficiency. After water-contaminated or dirty fluid passes through the main filter element 10, partially filtered fluid then passes through the supplemental cleanliness medium filter element 12, and then fully filtered fluid is received by a central filter cavity or volume 24. The fully filtered fluid then passes out of the overall filter F in a substantially axial direction 34.

[0070] Figure 19 illustrates an overall filter F with a supplemental cleanliness medium filter element 12, defined by a first frame 13 and individual supplemental filter elements 20, that is essentially the same as the supplemental fluid processing element shown in Figure 18. Again, one axial end 30 of the frame 13 is bonded or otherwise secured, together with an end of the main filter element 10, to a first end cap 14, while another axial end 32 of the frame 13 is bonded or otherwise secured, together with another end of the annular main filter element 10, to a second end cap 16 opposite the first end cap. In contrast to Figure 18, Figure 19 schematically illustrates the overall filter F as having a second frame 46 within which a plurality of individual coalescer elements 40 are mounted. Such coalescer elements serve in a known manner to pre-filter or pre- process fuel arriving from a fuel tank by increasing water droplet size, facilitating water repellency of hydrophobic media included in the main filter element 10. Typical coalescers are cellulose based or synthetic.

[0071] The second frame 46 shown has a circumferential lip 44, which may be receivable within a groove or recess defined on the interior of a fluid filter container cover (not shown in Figure 19). By snapping the lip 44 into the groove or recess defined in the container cover, the second frame 46, including the individual coalescer elements 40 mounted therein, is securable to and interlocks with the container cover. The second end cap 16 is schematically shown in Figure 19 as attached, by an annular layer of glue, for example, to an underside of an axial end wall 48 of the second frame 46. By attaching the first frame 13, with the individual supplemental cleanliness filter elements 20, and the second frame 46, including the individual coalescer elements 40, to the main filter element 10 by way of the second end cap 16 and the end wall 48, it is possible to produce an overall filter arrangement having combined main filtering, auxiliary filtering, and coalescing properties.

[0072] Figure 19 also illustrates an annular lip extending around a bottom end of the second frame 46 to provide a seal between the second frame 46 and an external outer housing (not shown) within which the arrangement shown is received during use. More specifically, the second frame 46 illustrated in Figure 19 has a circumferential lip 50 of plastic surrounding its open end opposite the annular axial end wall 48. The lip 50 is provided to produce a seal between the fluid filter container, within which the second frame 46 is received, and that second frame 46. The lip 50 thus facilitates fluid flow along an appropriate path.

[0073] Also illustrated in Figure 19 is an optional further frame 52, within which another set of individual coalescer elements 40 are mounted. The further frame 52, which may be used in place of or in combination with the second frame 46, illustrates an alternative manner for securing coalescer elements in place within the arrangement. As Figure 19 shows, an axial end 56 of the further frame 52 is bonded or otherwise secured, together with an end of the main filter 10 and the axial end 32 of the frame 13, to the second end cap 16.

[0074] The end wall 48 of the second frame 46 is also shown in Figure 19 as having a schematically represented bubble breaker 60 formed or mounted on its end. The bubble breaker 60 is optional, includes an open medium, and may be integrated with the filter to dissolve or reduce sizes of air pockets or bubbles in fluid passing through the filter. Air pockets or bubbles entrained in fluid supplied to the interior of the fluid filter container (not shown) tend to rise within the container interior, and fluid pressure causes the bubbles to proceed into bubble inlets. As fluid in which the bubbles are entrained passes into the bubble inlets and through filter media, the bubbles are broken up so that they will not adversely affect an engine or other item to which the fluid passing through the filter is supplied. Once the bubble breaker 60 has eliminated unwanted air from the fuel or other fluid, "de-bubbled" fuel or fluid is discharged back into the fluid flow appropriately, for example upstream of the main filter element.

[0075] It will be understood from the description supplied that, in the arrangement shown in Figure 19, by way of the bubble breaker 60, air pockets or bubbles in water-contaminated or dirty fluid are eliminated as that dirty or water-contaminated fluid is supplied under pressure from outside the second frame 46. Pre-processed fluid is produced as the water-contaminated or dirty fluid passes initially through the coalescer elements 40, and that pre-processed fluid then passes through the main filter element 10 in the direction 18. The resulting, partially filtered fluid then passes through the supplemental cleanliness medium filter element 12, and then fully filtered fluid is received by a central filter cavity or volume 24. The fully filtered fluid then passes out of the overall arrangement in the direction 34. [0076] Figure 20 is a sectional view of a compact three-stage design in which a first stage, formed as an oval or flat main filter element, provides particle filtration, a second stage, mounted at a radially inner surface of the first stage, operates as a coalescer and provides hydrophilic water separation and structural support, and a third stage, formed by meltblown material with a base layer, a hydrophobic medium, a combination of hydrophilic and hydrophobic media, or a combined hydrophilic - hydrophobic layer, is at least partly hydrophobic to provide water separation.

[0077] Figure 20, more specifically, shows a main filter element 10 to provide fine particle filtration, and a supplemental fluid processing element 62, defined by a coalescer. The coalescer has a frame 63 and multiple individual coalescer elements 40, essentially identical to the elements 40 shown in Figure 2. Figure 20 also has other characteristics in common with the arrangements shown in Figures 18-19, and an unnecessarily repetitive description of these characteristics is not provided. It is conceivable, of course, to utilize a combination of a main filter element 10 and a supplemental cleanliness medium filter 12 instead of just the main filter element 10 in the arrangement shown in Figure 20. The supplemental fluid processing element 62 shown in Figure 20 operates both to support the main filter element 10 and to filter or process filtered fluid exiting the main filter element 10 by increasing water droplet size, facilitating water repellency of the hydrophobic third stage. The hydrophobic third stage as illustrated is formed by an oval or flattened annulus 64 of water repellant material, such as meltblown material with a base layer, a hydrophobic medium, a combination of hydrophilic and hydrophobic media, or a combined hydrophilic— hydrophobic layer. Water droplets 66 are prevented by the layer 64 from passing, with the remainder of the fluid, from an outer filter interior cavity 68 to the inner central filter cavity or volume 24 and out of the arrangement in the direction 34. The separated water droplets 66 collect, by moving in a direction 72 within the outer filter cavity 68, in the outer filter cavity 68. Collected water droplets 66 can be drained from the outer filter cavity 68 appropriately, removed upon filter replacement, or returned to the fuel or other fluid being filtered without adverse consequences.

[0078] In operation, when the filter F shown in Figure 20 is used in a fuel filtering application for an internal combustion engine, for example, water- contaminated or dirty fuel received from a fuel tank (not shown) passes in a substantially radial direction 18 through the main filter element 10 under pressure, and is thus filtered initially by the annular main filter element 10. The filtered fuel then passes through the coalescer elements 40, and water droplets 66, entrained in the fluid, are prevented by the annulus 64 from passing, with the remainder of the fluid, from the outer filter cavity 68 to the inner filter cavity 24. As a result, only de-watered fluid is permitted to pass out of the arrangement in the direction 34.

[0079] Figure 21 is a sectional view of a compact three-stage design similar to that shown in Figure 20, but in which the hydrophobic third stage is provided in a space with reduced volume. This design may further include a bubble breaker, in which case it would be a four-stage design. Again, the arrangement shown in Figure 21 has many characteristics in common with the arrangements shown in Figures 18-20, and an unnecessarily repetitive description of these characteristics is not provided. Figure 21, for example, shows the illustrated arrangement as including a main filter element 10, end caps 14 and 16, with the end cap 16 affixed to the underside of a filter container cover 17, a frame 63, a plurality of individual coalescer elements 40, and a central filter cavity or volume 24. Here, however, the hydrophobic third stage is formed by a water separating element 64 with a reduced axial length, received in and mounted to a circumferentially inner surface of the frame 63, such that an end 70 of the element 64 defines a boundary of the central filter cavity or volume 24.

[0080] In operation, when the filter F shown in Figure 21 is used in a fuel filtering application for an internal combustion engine, for example, water- contaminated or dirty fuel received from a fuel tank (not shown) passes in the substantially radial direction 18 through the main filter element 10 under pressure, and is thus filtered initially by the annular main filter element 10. The filtered fuel then passes through the coalescer elements 40, and water droplets 66, entrained in the fluid, are prevented by the element end 70 from passing, with the remainder of the fluid, out of the central filter cavity or volume 24. Consequently, only filtered and partially, but adequately, de-watered fluid is permitted to pass out of the arrangement in the direction 34. Separated water droplets 66, repelled by the hydrophobic element 64, can collect in the cavity or volume 24 as they move away from the hydrophobic element 64 in a direction 76. [0081] Figure 22 is a sectional view of a compact four-stage design that is similar to the three-stage design shown in Figure 21, but in which both the hydrophobic third stage, formed by water separating element 64 with a reduced axial length, and a supplemental cleanliness medium filter element 12 are provided in series with the main filter element 10 and a frame 63 receiving individual coalescer elements 40. This design may further include a bubble breaker 60, in which case it would be a five-stage design. In operation, when the filter F shown in Figure 22 is used in a fuel filtering application for an internal combustion engine, for example, again, water-contaminated or dirty fuel received from a fuel tank (not shown) passes in a substantially radial direction 18 through the main filter element 10 under pressure, and is thus filtered initially by the annular main filter element 10. The filtered fuel then passes through the coalescer elements 40, and water droplets 66, entrained in the fluid, are prevented by the element 64 from passing, with the remainder of the fluid, out of the central filter cavity or volume 24. An end 70 of the element 64, again, forms a boundary of the cavity or volume 24. The water droplets collect in the central filter cavity or volume as they move in a direction 76 away from the hydrophobic third stage element 64. The supplemental cleanliness medium filter 12 is interposed between the hydrophobic element 64 and the filter outlet. Thus, only de-watered, twice-filtered fluid is permitted to pass out of the arrangement in the direction 34. [0082] Figure 23 is a sectional view of a main filter element 10 with a coalescer formed by individual coalescer elements 40 associated therewith. Fuel or other fluid is filtered as it traverses the filtration media of the main filter element 10 shown in Figure 23 radially in the direction 18, and then passes through the coalescer, which, again, receives water-contaminated fuel, and serves to increase water droplet size. Flow through the arrangement shown in Figure 23 proceeds in the directions indicated and exits the arrangement in the direction 34. The arrangement illustrated in Figure 23 has a bubble breaker 60 that is fully integrated centrally within the filter element for air bypass around the filter media. An arrangement such as that shown in Figure 23 operates to avoid passage of large, potentially damaging particles through the air bleed, permitting at most a constant air bleed with small bubbles. Periodic service (replacement) of the arrangement will involve replacement of the air bleed and avoids dirt build-up over the lifetime of the arrangement shown.

[0083] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.