Abstract: An underhood air cleaner (10) includes a plastic housing (12) having an inlet (14) for receiving dirty air, a filter element (18) for filtering the air, and an outlet (42) for discharging clean filtered air. A plastic outlet duct (40) is butt welded (50) to the housing outlet (42) in axially non-overlapping relation, to eliminate axial overlap previously required for a hose clamp, to reduce the amount of underhood space required by an engine air cleaner in the axial direction.

Abstract: An open flow fluid filter has a pleated main filter element having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips. The loop has a hollow interior extending along an axis. Fluid to be filtered flows through the main filter element from an upstream dirty side to a downstream clean side, and flows axially in the hollow interior. The main filter element has an axial flow passage extending along the axis and circumscribing the hollow interior and has a flow perimeter greater than the inner perimeter. A safety filter element downstream of the main filter element filters both the axial flow in the hollow interior and additional flow between the flow perimeter and the inner perimeter. A filter with additional flow is also provided.

Abstract: A filter (10), including an inside-out reverse flow air filter, has an annular filter element (20) with an upper end cap (24) provided by a resiliently compressible trifunctional member having: (a) a wall (50) deflecting debris radially outwardly within the housing away from the central opening (26) of the hollow filter interior (22); (b) an air entrance guide throat (52) directing air to the central opening (26) with reduced restriction; and (c) a sealing surface (54) sealed to the housing and blocking air flow from the inlet (28) to the outlet (34) otherwise bypassing the filter element. In further embodiments, simplified and cost reduced sealing is provided by a configured end cap.

Abstract: An inside-out reverse flow air filter element (20) has a resiliendtly compressible molded lower end cap (48) having molded drainage surfaces including a molded raised central dome (72) shedding moisture radially outwardly and downwardly, a plurality of molded drainage holes (70, 74, 76, 78) spaced radially outwardly of and below the top of the central dome, and a plurality of radial segments (98, 100, 102, 104, 110, 112, 114, 116), an annular trough (80) and tapered slope surfaces (82, 84) providing desired drainage. A mold (130) has a plurality of upstanding segments (136, 138, 140, 142) having posts (144) and ramps (146) forming the drainage structure, and locator faces (152) engaging, guiding and locating the annular filter media (34) in the mold.

Abstract: An inside-out reverse flow air filter element (20) has a resiliently compressible molded lower end cap (48) having molded drainage surfaces including a molded raised central dome (72) shedding moisture radially outwardly and downwardly, a plurality of molded drainage holes (70, 74, 76, 78) spaced radially outwardly of and below the top of the central dome, and a plurality of radial segments (98, 100, 102, 104, 110, 112, 114, 116), an annular trough (80) and tapered slope surfaces (82, 84) providing desired drainage. A mold (130) has a plurality of upstanding segments (136, 138, 140, 142) having posts (144) and ramps (146) forming the drainage structure, and locator faces (152) engaging, guiding and locating the annular filter media (34) in the mold.

Abstract: An open flow fluid filter has a pleated main filter element having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips. The loop has a hollow interior extending along an axis. Fluid to be filtered flows through the main filter element from an upstream dirty side to a downstream clean side, and flows axially in the hollow interior. The main filter element has an axial flow passage extending along the axis and circumscribing the hollow interior and has a flow perimeter greater than the inner perimeter. A safety filter element downstream of the main filter element filters both the axial flow in the hollow interior and additional flow between the flow perimeter and the inner perimeter. A filter with additional flow is also provided.

Abstract: An air filter housing (12) includes twist and lock structure (46) having a first position (FIGS. 5, 6) permitting axial movement (120) of a cover (44) and base (38) relative to each other, and being rotatable in a first direction (48) from the first position (FIG. 6) to the second position (FIG. 7), and in the second position (FIG. 7) preventing axial movement of the base (38) and cover (44) relative to each other, and being rotatable in a second opposite direction (78) from the second position (FIG. 7) to the first position (FIG. 6). Anti-rotation lock structure (80) provides a rotational retention force holding the twist and lock structure (46) in the second position (FIG. 7).

Abstract: An underhood air cleaner (20) for a vehicle (22) has an inlet shroud seal (72) self-mounted to the filter housing (60) at the filter inlet (68) and engaging the hood (28) at the exit opening (36) of the hood air channel (30). The self-mounting is accomplished without extra parts or fasteners such as bolts and clamps. Both axial (198) and radial (200) retention is provided for the shroud seal (72) on the filter housing (60), as well as reduced inflow restriction.

Abstract: An open flow fluid filter has a pleated main filter element having a plurality of pleats in a closed loop having an outer perimeter defined by a plurality of outer pleat tips, and an inner perimeter defined by a plurality of inner pleat tips. The loop has a hollow interior extending along an axis. Fluid to be filtered flows through the main filter element from an upstream dirty side to a downstream clean side, and flows axially in the hollow interior. The main filter element has an axial flow passage extending along the axis and circumscribing the hollow interior and has a flow perimeter greater than the inner perimeter. A safety filter element downstream of the main filter element filters both the axial flow in the hollow interior and additional flow between the flow perimeter and the inner perimeter. A filter with additional flow is also provided.

Abstract: A filter element (202, 250) includes pleated filter media (26) having a plurality of pleats (28) in a closed annular loop having an outer perimeter (30) defined by a plurality of outer pleat tips (32), an inner perimeter (34) defined by a plurality of inner pleat tips (36), the loop having a hollow interior (38) extending along an axis (40), wherein fluid to be filtered flows laterally through the filter media and flows axially in the hollow interior (38). The filter element has an axial flow passage (56a) along the axis (40) and circumscribing the hollow interior (38) and has a flow perimeter (218) greater than the inner perimeter (34) of the filter element defined by the inner pleat tips (36), and in the preferred embodiment substantially the same as the outer perimeter (30) defined by the outer pleat tips (32), to provide axial flow (58) through the hollow interior (38) and additional axial flow (59 and 59a) through the axial ends (68) of the pleats.

Abstract: Enhanced performance fibrous media (60) is provided by orienting filter media fibers (62) dominantly parallel to the fluid flow direction (46). Filter media construction is provided by a sheet (80) having an internal pleated subsheet (88) with pleats (92, 94) engaging and packed against each other sufficiently tightly and bonded (104) such that fluid flows along the flow direction through the pleats in parallel therewith, rather than between the pleats and then transversely therethrough. An extended life two-stage fluid filter assembly includes first and second filter elements (80 and 112), wherein the pleats (114, 116) of a main downstream filter element (112) are spaced from each other along a spacing direction (122) transverse to the flow direction (46) and defining a transverse gap (124) therebetween through which fluid flows, and wherein the pleats (92, 94) of an upstream prefilter element (80) are packed against each other without such transverse gap and blocking fluid flow therebetween.

Abstract: A filter (10) has a housing (12) extending along an axis (18) between first and second axial ends (20 and 22), and has a closed loop primary filter element (24) extending axially in the housing, and a closed loop safety filter element (48) in the hollow interior (30) of the primary filter element. A detent member (60) engages and retains the end cap (54) of the safety filter element independently of the primary filter element to retain the safety filter element in housing upon removal of the primary filter element from the housing.

Abstract: A filter element (202, 250) includes pleated filter media (26) having a plurality of pleats (28) in a closed annular loop having an outer perimeter (30) defined by a plurality of outer pleat tips (32), an inner perimeter (34) defined by a plurality of inner pleat tips (36), the loop having a hollow interior (38) extending along an axis (40), wherein fluid to be filtered flows laterally through the filter media and flows axially in the hollow interior (38). The filter element has an axial flow passage (56a) along the axis (40) and circumscribing the hollow interior (38) and has a flow perimeter (218) greater than the inner perimeter (34) of the filter element defined by the inner pleat tips (36), and in the preferred embodiment substantially the same as the outer perimeter (30) defined by the outer pleat tips (32), to provide axial flow (58) through the hollow interior (38) and additional axial flow (59 and 59a) through the axial ends (68) of the pleats.

Abstract: A filter element (22) includes pleated filter media (26) having a plurality of pleats (28) in a closed annular loop having an outer perimeter (30) defined by a plurality of outer pleat tips (32), and an inner perimeter (34) defined by a plurality of inner pleat tips (36), the closed annular loop having a hollow interior (38) extending along an axis (40), wherein fluid to be filtered flows laterally through the filter media and flows axially (58) in the hollow interior (38). The filter element (22) has an axial flow passage (56) along the axis (40) and circumscribing the hollow interior (38) and has a flow perimeter (60) greater than the inner perimeter (34) of the filter element defined by the inner pleat tips (36). An end cap (66) of resilient compressible material at the axial end (62) of the filter element bears radially between and is radially compressed between an outer liner (102) and a flow tube (90) at the enlarged flow passage (56).

Abstract: A filter element (202, 250) includes pleated filter media (26) having a plurality of pleats (28) in a closed annular loop having an outer perimeter (30) defined by a plurality of outer pleat tips (32), an inner perimeter (34) defined by a plurality of inner pleat tips (36), the loop having a hollow interior (38) extending along an axis (40), wherein fluid to be filtered flows laterally through the filter media and flows axially in the hollow interior (38). The filter element has an axial flow passage (56a) along the axis (40) and circumscribing the hollow interior (38) and has a flow perimeter (218) greater than the inner perimeter (34) of the filter element defined by the inner pleat tips (36), and in the preferred embodiment substantially the same as the outer perimeter (30) defined by the outer pleat tips (32), to provide axial flow (58) through the hollow interior (38) and additional axial flow (59 and 59a) through the axial ends (68) of the pleats.

Abstract: A filter element (22) includes pleated filter media (26) having a plurality of pleats (28) in a closed annular loop having an outer perimeter (30) defined by a plurality of outer pleat tips (32), and an inner perimeter (34) defined by a plurality of inner pleat tips (36), the closed annular loop having a hollow interior (38) extending along an axis (40), wherein fluid to be filtered flows laterally through the filter media and flows axially (58) in the hollow interior (38). The filter element (22) has an axial flow passage (56) along the axis (40) and circumscribing the hollow interior (38) and has a flow perimeter (60) greater than the inner perimeter (34) of the filter element defined by the inner pleat tips (36). An end cap (66) of resilient compressible material at the axial end (62) of the filter element bears radially between and is radially compressed between an outer liner (102) and a flow tube (90) at the enlarged flow passage (56).