In-situ modular cleanable filter

[0002] The invention relates to fluid filters for filtering fluid from a machine, including spin-on type oil filters for internal combustion engines and hydraulic equipment, and more particularly to an in-situ cleanable filter facilitating modularity meeting evolving market demands.

[0003] The present invention arose during further development efforts relating to the subject matter of commonly owned U.S. Pat. Nos. 5,462,679, 5,779,900, 5,858,224, and allowed U.S. application Ser. No. 08/755,479, filed Nov. 22, 1996, all incorporated herein by reference. Such subject matter generally relates to cleanable filters, including oil filters, and more particularly to the use of a cleaning fluid, such as pressurized air, to clean the filter at a convenient site relative to the installation of the filter on a machine such as an internal combustion engine.

[0004] In prior art cleanable oil filters, it is typical that the oil inlet and outlet are separated from the oil drain and air inlet. The oil inlet and outlet are typically at the top of the filter housing, while the oil drain and air inlet are at the bottom of the filter housing. Separation of the oil inlet and drain reduces potential contamination of upstream oil flow lines by backflushed contaminant. The bottom air inlet ensures that air bubbled through the oil creates a foam prior to reaching the filter media.

[0005] Separation of the oil inlet, oil outlet, oil drain and air inlet may not be conducive to certain evolving modular designs using a permanent assembly intended to be part of the engine or equipment. In such modular designs, it is desired that the filter assembly include not only a cleanable and replaceable cartridge filter element, but also associated plumbing. Modular designs bolted onto the engine or equipment are becoming increasingly popular. The present invention addresses and solves this need in a particularly simple and efficient manner.

[0006] FIG. 1 is a schematic view partially in section showing a filter in accordance with the invention, in the filtration mode.

[0007] FIG. 2 is like FIG. 1 and shows the filter in the cleaning mode.

[0008] FIG. 1 shows a filter 10 for filtering fluid from a machine such as internal combustion 12. Filter housing 14 has a first inlet 16 receiving a first fluid such as oil from engine 12 as shown at arrow 18. The housing a first outlet 20 returning the oil to engine 12 as shown at arrow 22. The housing has a second inlet 24, FIG. 2, selectively receiving a second fluid such as pressurized air as shown at arrow 26 from a source of cleaning fluid such as pressurized air source 28. The housing has a second outlet exhausting the cleaning fluid such as air, and the backflushed contaminant and oil as shown at arrow 32 to oil drain collection container 34 for disposal. Housing 14 extends axially along axis 35 between first and second axially distally opposite first and second axial ends 36 and 38. A cleanable and replaceable cartridge filter element 40 extends axially within the housing and is provided by a standard annular pleated element as is known in the art. In the disclosed embodiment, the upper end of filter element 40 is closed by a filter cap 42 extending across the filter element including the hollow interior 44 thereof. A central support tube 46 extends axially upwardly into hollow interior 44 and is perforated as at 48 to permit flow therethrough. The lower end of filter element 40 has an annular end cap 50 sealed to tube 46 by an annular O-ring 52 providing a radially sealing gasket. Alternatively, filter element 40 may extend all the way down to axial surface 54 of the housing and be axially sealed thereagainst by end cap 50, with axial clamping pressure applied by removable end cap 56 which may be clamped, threaded or otherwise attached to housing 14. Further alternatively, tube 46 may be eliminated, or extend only partially upwardly into hollow interior 44 with or without radial seal 52.

[0009] Filter housing 14 has a first flow path therethrough, FIG. 1, as shown at arrow 18 from first inlet 16 then through flow channel 58 as shown at arrow 60 into annular space or gap 62 between filter element 40 and axially extending sidewall 64 of the housing then radially inwardly through filter element 40 as shown at arrows 66 into hollow interior 44 then through flow channel 68 as shown at arrow 70 then to first outlet 20 as shown at arrow 22. Filter housing 14 has a second flow path therethrough, FIG. 2, for the pressurized air or cleaning fluid from second inlet 24 as shown at arrow 26 then through flow channel 68 as shown at arrow 72 into hollow interior 44 then radially outwardly through filter element 40 as shown at arrows 74 into annular gap 62 then through flow channel 58 as shown at arrow 76 then to outlet 30 as shown at arrow 78. The noted first and second flow paths have common but opposite direction portions through filter element 40 as shown at arrows 66, FIG. 1, and 74, FIG. 2. The noted first and second flow paths have common but opposite direction portions through first common flow channel 58 as shown at arrows 60, FIG. 1, and 76, FIG. 2. The noted first and second flow paths have common but opposite direction portions through second common flow channel 68 as shown at arrows 70, FIG. 1, and 72, FIG. 2. First common flow channel 58 in housing 14 communicates with first inlet 16 and second outlet 30. Second common flow channel 68 in housing 14 communicates with first outlet 20 and second inlet 24.

[0010] Filter element 40 has an upstream dirty side 80 and a downstream clean side 82. The noted first fluid or oil flowing along the noted first flow path flows from upstream dirty side 80 to downstream clean side 82 as shown at arrows 66, FIG. 1. First common flow channel 58 communicates with upstream dirty side 80 of filter element 40 and is between first inlet 16 and second outlet 30. Second common flow channel 68 communicates with downstream clean side 82 of filter element 40 and is between first outlet 20 and second inlet 24.

[0011] A first valve 84 in the housing has a first state, FIG. 1, closing second outlet 30, and has a second state, FIG. 2, opening outlet 30. A second valve 86 in the housing has a first state, FIG. 1, providing communication of downstream clean side 82 of filter element 40 to first outlet 20, as shown at arrow 70. Valve 86 has a second state, FIG. 2, providing communication of second inlet 24 to downstream clean side 82 of filter element 40, as shown at arrow 72. Valve 84 is preferably a petcock or the like externally actuated between open and closed states by the operator. Valve 86 is a plunger biased rightwardly in FIG. 1 by spring 88, and movable leftwardly by air pressure at inlet 24 from air pressure source 28 to overcome spring 88. Valve 86 in the noted first state, FIG. 1, blocks communication between downstream clean side 82 of filter element 40 and second inlet 24. Valve 86 in the noted first state, FIG. 1, blocks communication between first outlet 20 and second inlet 24. Valve 86 in the noted second state, FIG. 2, blocks communication between downstream clean side 82 of filter element 40 and first outlet 20. Valve 86 in the noted second state, FIG. 2, blocks communication between second inlet 24 and first outlet 20. Valve 86 is in second flow channel 68 and is between first outlet 20 and second inlet 24. Valve 84 has been disclosed as an on-off valve, and valve 86 has been disclosed as a three-way valve. Alternatively, valve 84 may be a three-way valve and/or valve 86 may be an on-off valve.

[0012] Filter 10 has a filtration mode, FIG. 1, with the first fluid such as oil flowing along the noted first flow path. Filter 10 has a cleaning mode, FIG. 2, with the second fluid such as pressurized air flowing along the noted second flow path. First valve 84 is in its noted closed first state in the filtration mode of the filter, FIG. 1, and the first fluid such as oil flows in a first direction 60 through first common flow channel 58. First valve 84 is in its noted open second state in the cleaning mode of the filter, FIG. 2, and the second fluid such as pressurized air flows in a second direction 76 through first common flow channel 58. Directions 76 and 60 are opposite to each other in flow channel 58. Second valve 86 is in its noted rightward first state in the filtration mode of the filter, FIG. 1, and the first fluid such as oil flows in a first direction 70 through second common flow channel 68. Second valve 86 is in its noted leftward second state in the noted cleaning mode of the filter, FIG. 2, and the second fluid such as pressurized air flows in a second direction 72 through second common flow channel 68. Directions 72 and 70 are opposite to each other through flow channel 68. Second valve 86 blocks communication between second inlet 24 and first outlet 20 in each of its noted first and second states in the filtration and cleaning modes, respectively. Second valve 86 in its noted rightward first state in the filtration mode of the filter, FIG. 1, blocks communication between downstream clean side 82 of filter element 40 and second inlet 24. Second valve 86 in its noted leftward second state in the cleaning mode of the filter, FIG. 2, blocks communication between downstream clean side 82 of filter element 40 and first outlet 20.

[0013] As noted above, filter housing 14 extends axially between first and second axially spaced distally opposite ends 36 and 38. Both of the first and second inlets 16 and 24 and both of the first and second outlets 20 and 30 are at first axial end 36 of the housing. As noted above, filter element 40 extends axially in housing 14 and has a hollow interior 44. Second common flow channel 68 is axially aligned with hollow interior 44. As noted above, housing 14 has an axially extending sidewall 64 spaced radially outwardly of filter element 40 by a gap 62. First common flow channel 58 is preferably axially aligned with and axially spaced from gap 62. Cover 56 is provided at second axial end 38 of the housing and is removable therefrom to permit access to and axial removal and replacement of filter element 40. Filter element 40 is an annular member of given outer diameter, and cover 56 has a diameter greater than the outer diameter of filter element 40.

[0014] First common flow channel 58 is provided by a junction 89 having an axially extending trunk 90 and first and second laterally extending arms 92 and 94. Trunk 90 communicates with upstream dirty side 80 of filter element 40. First arm 92 communicates with first inlet 16. Second arm 94 communicates with second outlet 30. Second common flow channel 68 is provided by a second junction 95 having an axially extending trunk 96 and first and second laterally extending arms 98 and 100. Trunk 96 communicates with downstream clean side 82 of filter element 40. First arm 98 communicates with first outlet 20. Second arm 100 communicates with second inlet 24. Trunk 96 is preferably along axial centerline 102 of the housing. First valve 84 is preferably in second arm 94 of first junction 89. Second valve 86 is preferably in trunk 96 of second junction 95. Trunk 90 of first junction 89 is laterally spaced from trunk 96 of second junction 95. First and second arms 92 and 94 of first junction 89 are axially spaced from first and second arms 98 and 100 of second junction 95. Trunks 90 and 96 of first and second junctions 89 and 95 extend parallel to each other. First and second arms 92 and 94, and 98 and 100, of first and second junctions 89 and 95 extend in spaced parallel planes. Each of junctions 89 and 95 is disclosed as a T-junction, with respective arms 92 and 94, and 98 and 100, extending distally oppositely from each other, i.e. extending radially outwardly from the axis of its respective trunk 180° apart. Alternatively, other types of junctions may be used, including where the arms extend radially outwardly from a respective trunk at an angle less than 180° therebetween, for example arm 92 of junction 89 may extend leftwardly as shown in FIG. 1, but arm 94 may extend out of the page rather than rightwardly as shown in FIG. 1. Other variations are possible for the noted junctions.

[0015] It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.