Filter element and in-tank filter assembly and methods

Abstract

An in-tank filter assembly includes a removable and replaceable filter element for a hydraulic tank. The filter element has a filter construction and a bypass construction positioned radially outside of the outer perimeter of the filter construction. An end cap arrangement has a filter opening in communication with an open filter interior volume of the filter construction and a bypass opening in communication with an open tube interior volume of the bypass flow tube. A filter seal member is secured to the end cap arrangement and encloses both the filter construction and the bypass construction.

Description

FILTER ELEMENT AND IN-TANK FILTER ASSEMBLY AND METHODS

[0001] RELATED APPLICATION

[0002] This is being filed as a PCT Application. Applicant claims the benefit of and priority to U.S. Provisional Application No. 63 / 625,128, filed January 25, 2024, which is incorporated herein by reference.

[0003] TECHNICAL FIELD

[0004] This disclosure relates generally a filter element and an in-tank filter assembly and methods. In particular, the disclosure describes a filter element having a main construction and a bypass construction for removable replacement in a hydraulic tank.

[0005] BACKGROUND

[0006] Liquid filters are employed in a variety of applications, including, for example, hydraulic systems. One general type of filtration system is sometimes referenced as “in-tank.” In-tank filter systems are described, for example, in PCT publication WO 2005 / 063358, published Jul. 14, 2005; and, in PCT publication WO 2008 / 030323, published Mar. 13, 2008. Each of these two PCT publications is incorporated herein by reference.

[0007] In general terms, an “in-tank” filter system, is a system configured to be mounted on a reservoir tank for the liquid involved. The system will typically provide for at least one of: liquid flow to the tank; or, draw of liquid from the tank. Typically, an in-tank filter assembly includes a housing having a removable, i.e. serviceable, filter element or cartridge appropriately positioned therein. The service element is periodically removed for servicing, for example when it becomes sufficiently occluded to generate an undesirable level of restriction across the filter media, or when a service interval is passed. Servicing typically involves one of: replacing with a new filter element; replacing with a previously used, but refurbished, filter cartridge; or, in some manner cleaning the removed cartridge and replacing it for further use.

[0008] Continuing improvements in in-tank filter assemblies are desirable.

[0009] SUMMARY

[0010] In an aspect, a removable and replaceable filter element for use in a hydraulic tank is provided. The filter element comprises a filter construction having a tubular extension of filter media surrounding an open filter interior volume; the filter construction having a first end and an opposite second end and an outer perimeter; a bypass construction positioned radially outside of the outer perimeter; the bypass construction having a bypass flow tube with an open tube interior volume; the bypass flow tube having a first end and an exit arrangement; a bypass seal member circumscribing the bypass flow tube to form a seal between the bypass flow tube and the hydraulic tank, when the filter element is installed in the hydraulic tank;an end cap arrangement at the first end of the filter construction and at the first end of the flow tube; the end cap arrangement having a filter opening in communication with the open filter interior volume of the filter construction; the end cap arrangement having a bypass opening in communication with the open tube interior volume of the bypass flow tube; and a filter seal member secured to the end cap arrangement and enclosing both the filter construction and the bypass construction; the filter seal member positioned to form a seal between the end cap arrangement and the hydraulic tank, when the filter element is installed in the hydraulic tank.

[0011] In example embodiments, the filter element further including a closed end cap at the second end of the filter construction.

[0012] In arrangements, the exit arrangement of the bypass construction includes a filter screen to filter bypass fluid.

[0013] Some embodiments include the end cap arrangement having an outer perimeter wall; and the filter seal member being along the outer perimeter wall.

[0014] In examples, the filter seal member is an o-ring seal member; and the bypass seal member is an o-ring seal member.

[0015] Preferably, a longitudinal axis of the bypass construction is parallel to the filter construction.

[0016] Preferably, the filter seal member and the bypass seal member have different outside shapes.

[0017] In some examples, the filter seal member is egg-shaped.

[0018] In some examples, the filter seal member is obround.

[0019] In some examples, the filter seal member is racetrack shaped, having two curved sections joined by two straight sections.

[0020] Tn some examples, the filter seal member has a first curved section and an opposite second curved section; and the first curved section and second curved section have different radii of curvature.

[0021] In one arrangement, the radius of curvature of the first curved section is between 0.5 and 0.8 of the radius of curvature of the second curved section.

[0022] In one arrangement, the radius of curvature of the first curved section is between 0.6 and 0.7 of the radius of curvature of the second curved section.

[0023] In some examples, the filter seal member has a first curved section and an opposite second curved section and a longitudinal axis extending through the first curved section and second curved section; the filter seal member being symmetrical about the longitudinal axis.

[0024] In some examples, the filter seal member has a first curved section and an opposite second curved section and a longitudinal axis extending through the first curved section and second curved section; the filter seal member being asymmetrical about the longitudinal axis.

[0025] In some examples, the bypass seal member is axially spaced from the filter seal member.

[0026] In some examples, the bypass seal member is axially spaced from the filter seal member by about 20-30 mm.

[0027] Preferably, the filter media is pleated media.

[0028] In some embodiments, the bypass construction has an axial length less than 30% and greater than 5% of an axial length of the filter construction.

[0029] In some embodiments, the bypass construction has an axial length less than 25% and greater than 10% of an axial length of the filter construction.

[0030] In some examples, the end cap arrangement includes a handle axially projecting therefrom, in a direction away from the filter construction.

[0031] In some examples, the handle comprises a grip bar bridging over the filter opening.

[0032] In some examples, the bypass flow tube is integrally molded with the end cap arrangement.

[0033] In some examples, the filter screen is co-injected or co-molded with the end cap arrangement and bypass flow tube.

[0034] In another aspect, an in-tank filter assembly is provided. The in-tank filter assembly comprises a tank for holding a filtered hydraulic fluid; the tank having an inlet with a centralaxis, an outlet, a filter opening, and a removable cover member over the filter opening; the tank also including a main filter housing and a bypass housing; the bypass housing being radially outside of the main filter housing; a bypass valve held by the bypass housing; a filter element removably and replaceably seated in the tank; the filter element having a filter construction with a first longitudinal axis positioned in the main filter housing, and a bypass construction with a second longitudinal axis positioned in the bypass housing; and a filter seal member enclosing both the filter construction and the bypass construction.

[0035] In some examples, the first and second longitudinal axes are perpendicular to the central axis of the inlet.

[0036] In some examples, the filter element comprises: the filter construction having a tubular extension of filter media surrounding an open filter interior volume; the filter construction having a first end and an opposite second end and an outer perimeter; the bypass construction positioned radially outside of the outer perimeter; the bypass construction having a bypass flow tube with an open tube interior volume; the bypass flow tube having a first end and an exit arrangement; the exit arrangement being in communication with the bypass valve; a bypass seal member circumscribing the bypass flow tube and forming a releasable seal between the bypass flow tube and the bypass housing; an end cap arrangement at the first end of the filter construction and at the first end of the flow tube; the end cap arrangement having a filter opening in communication with the open filter interior volume of the filter construction; the end cap arrangement having a bypass opening in communication with the open tube interior volume of the bypass flow tube; and the filter seal member being secured to the end cap arrangement and forming a seal between the end cap arrangement and the hydraulic tank.

[0037] In some examples, the bypass housing includes: a surrounding wall with a first open end and an opposite second open end; the second open end holding the bypass valve; the first open end being sized to receive the bypass flow tube; the surrounding wall having a section of through apertures providing communication between an interior of the bypass housing and a remaining interior of the tank; and the bypass seal member forming the releasable seal against an interior of the surrounding wall and axially between the bypass valve and the section of through apertures.

[0038] In some examples, the exit arrangement of the bypass construction includes a filter screen to filter bypass fluid.

[0039] Tn some arrangements, the assembly further includes a strainer in the main filter housing and surrounding the filter construction.

[0040] In some examples, the bypass construction is parallel to the filter construction.

[0041] Preferably, the filter element is according any one of the above characterizations.

[0042] In another aspect, a method of servicing an in-tank filter assembly is provided. A method of servicing an in-tank filter assembly comprises: removing the cover member of a hydraulic tank to expose a tank opening; removing a filter element from the tank through the opening; the filter element having a filter construction and a bypass construction located radially outside of the filter construction; wherein the step of removing includes: breaking a filter seal between the filter element and the tank, in which the seal encloses both the filter construction and the bypass construction; and breaking a bypass seal between the bypass construction and the tank.

[0043] In some examples, the step of removing the filter element includes grasping a handle extending from the filter element.

[0044] Preferably, method includes using the filter element comprised the filter element according any one of the above characterizations.

[0045] It is noted that not all the specific features described herein need to be incorporated in an arrangement for the arrangement to have some selected advantage according to the present disclosure.

[0046] BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG. l is a perspective view of an in-tank filter assembly, constructed in accordance with principles of this disclosure;

[0048] FIG. 2 is an exploded view of the in-tank filter assembly of FIG. 1, showing a tank for hydraulic fluid and a removable and replaceable service filter element;

[0049] FIG. 3 is a cross-sectional view of the in-tank filter assembly of FIG. 1;

[0050] FIG. 4 is a cross-sectional view of the in-tank filter assembly of FIG. 1, with the filter element removed and the service cover member off;

[0051] FIG. 5 is a front elevational view of the filter element used in the in-tank filter assembly of FIG. 1;

[0052] FIG. 6 is a top perspective view of the filter element of FIG. 5;

[0053] FIG. 7 is a bottom perspective view of the filter element of FIG. 5;

[0054] FIG. 8 is a top plan view of the filter element of FIG. 5;

[0055] FIG. 9 is a perspective, cross-sectional view of a portion of the in-tank filter assembly of FIG. 1, showing the filter element sealed in operable position in the tank;

[0056] FIG. 10 is an enlarged, perspective, cross-sectional view of a portion of an bypass housing in the interior of the tank;

[0057] FIG. 11 is a perspective, cross-sectional view of a portion of the in-tank filter assembly of FIG. 1, showing the filter element sealed in operable position in the tank and showing the service cover member grounded to the tank with a metal strap.

[0058] DETAILED DESCRIPTION

[0059] Overview of assembly

[0060] In reference to FIGS. 1 and 2, an example embodiment of an in-tank filter assembly is illustrated at 20. In this example embodiment, the assembly 20 includes a tank 22. The tank 22 holds fluid (liquid), such as a hydraulic fluid or oil. The tank 22 has an outer, surrounding wall 24 which surrounds an interior 26 of the tank 22. The tank interior 26 holds the hydraulic fluid and also houses a filter element 30. The filter element 30 is selectively removable from the tank 22 through a service opening 32 in an upper wall 34 of the tank 22. A service cover member 36 covers the service opening 32, and is shown as being secured with fasteners 38. A seal member 39 forms a releasable seal between and against the service cover member 36 and the upper wall 34 of the tank 22.

[0061] The tank 22 further has a liquid flow inlet 40 with a central axis 41 (FIG. 3) and a liquid flow outlet 42. The inlet 40 carries fluid to be cleaned (filtered) by the filter element 30. The filtered liquid is stored in the tank interior 26. When equipment needs hydraulic fluid, it is drawn from the interior 26 through the outlet 42. An optional breather member 44 is also shown in communication with the tank interior 26, along the upper wall 34.

[0062] Referring now to FIG. 4, the tank interior 26 includes a main filter housing 46 and a bypass housing 48. The main filter housing 46 and bypass housing 48 are formed by internalwalls within the interior 26 of the tank 22, which are structured to hold and support the filter element 30. The bypass housing 48 is radially outside of the main filter housing 46.

[0063] Also visible in FIGS. 2 and 4 is an optional strainer 50, which lines the main filter housing 46 and is downstream of and surrounds the filter element 30. A bypass valve 52 is held by the bypass housing 48. The filter housing 46 or strainer 50 may also be referred to as an outer liner. The strainer 50 or outer liner can be either part of the tank 22 / housing or integrated with the filter element 30.

[0064] Filter element 30

[0065] In reference now to FIGS. 5-7, an example embodiment of the filter element 30 is illustrated. The filter element 30 includes a filter construction 60. The filter construction 60 has a tubular extension of filter media 62 surrounding an open filter interior volume 64 (FIG. 3). By “tubular”, it is meant that it forms a tube, but can be cylindrical, oval, obround, or various other tubular shapes. The filter media 62 is preferably pleated media 66, but may also be other types of media. The filter construction 60 has a first end 68 and an opposite second end 70 and an outer perimeter 72.

[0066] The filter element 30 further includes a bypass construction 74. The bypass construction 74 is positioned radially outside of the outer perimeter 72. By “radially outside”, it is meant that the bypass construction 74 (whole or partially) is not within or overlap any part of the filter construction 60.

[0067] The bypass construction 74 has a bypass flow tube 76 with an open tube interior volume 78 (FIG. 3). The bypass flow tube 76 has a first end 80 and an exit arrangement 82. The exit arrangement 82 can be many forms of openings to allow the flow of bypass fluid, and in the example illustrated, the exit arrangement 82 includes an optional filter screen 84. The filter screen 84, in the example embodiment, is tubular shaped with screen material along a side 86 of the tube shape and with screen material closing the bottom 88 of the tube shape. The filter screen 84 is positioned to provide a coarse filtration of bypass fluid flow.

[0068] The bypass construction 74 includes a bypass seal member 90 circumscribing the bypass flow tube 76. The bypass seal member 90 is positioned to form a seal 92 (FIG. 9) between the bypass flow tube 76 and the hydraulic tank 22, when the filter element 30 is installed in the hydraulic tank 22. In FIG. 9, it can be seen how the seal 92 is between andagainst the bypass flow tube 76 and the bypass housing 48 in the tank interior 26. While many different types of seals can be used, in the example shown, the bypass seal member 90 is an externally radially directed o-ring seal member 94.

[0069] The filter element 30 further includes an end cap arrangement. The end cap arrangement 96 is at the first end 68 of the filter construction 60 and at the first end 80 of the flow tube 76.

[0070] The end cap arrangement 96 has a filter opening 98 in communication with the open filter interior volume 64 of the filter construction 60. The filter opening 98 allows for the passage of fluid into the filter interior volume 64 after it flows into the tank 22 through the inlet 40. The fluid is then filtered by flowing through the filter media 62 from the interior volume 64 to outside of the filter media 62.

[0071] The end cap arrangement 96 has a bypass opening 100 in communication with the open tube interior volume 78 of the bypass flow tube 76. The bypass opening 100 allows the flow of fluid into the bypass flow tube 76, when filter occlusion occurs, preventing the flow of fluid through the filter media 62.

[0072] A filter seal member 102 is secured to the end cap arrangement 96 and encloses both the filter construction 60 and the bypass construction 74. The filter seal member 102 is positioned to form a seal 104 (FIG. 9) between the end cap arrangement 96 and the hydraulic tank 22, when the filter element 30 is installed in the hydraulic tank 22. While many different types of seals can be used, in the example shown, the filter seal member 102 is an externally radially directed o-ring seal member 106.

[0073] The filter element 30 can further include an end cap 108 at the second end 70 of the filter construction 60. In the example shown, the end cap 108 is a closed end cap 108. In other examples, the end cap 108 can be open to accommodate standpipes, or valves, or other features.

[0074] The bypass construction 74 is arranged relative to the filter construction 60, such that they are adjacent to each other. In the example shown in FIG. 5, the bypass construction 74 has a longitudinal axis 110 that is parallel to a longitudinal axis 112 of the filter construction 60.

[0075] Still in reference to FIG. 5, it can be seen how the bypass seal member 90 is axially spaced by distance D from the filter seal member 102. For example, the distance D can be about 20-30 mm.

[0076] The bypass construction 74 is preferably adjacent to, and extends along side, the fdter construction 60, but they have different lengths. For example, the bypass construction 74 has an axial length less than 30% and greater than 5% of an axial length of the fdter construction 60. Preferably, the bypass construction 74 has an axial length less than 25% and greater than 10% of an axial length of the fdter construction 60.

[0077] In reference now to FIG. 6, the end cap arrangement 96 optionally includes a handle 114. The handle 114 allows a person servicing the assembly 20 to more easily remove the element 30 from the tank 22. The handle 114 can have many different embodiments. As shown in the example, the handle 114 axially projects from a remainder of the element 30 and from the end cap arrangement 96 in a direction away from the fdter construction 60. In the example shown, the handle 114 comprises a grip bar 116 bridging over the fdter opening 98. The grip bar 116 is sized to be grasped by a human hand, to accommodate 2-4 fingers between the bar 116 and the remainder of the end cap arrangement 96, with the thumb along the outside of the bar 116.

[0078] In reference now to FIG. 5, the bypass flow tube 76 is fixed to the end cap arrangement 96. Preferably, the bypass flow tube 76 is integrally molded with the end cap arrangement 96. Optionally, the fdter screen 84 can be co-injected or co-molded with the end cap arrangement 96 and the bypass flow tube 75.

[0079] From a review of FIGS. 6-8, the end cap arrangement 96 is shown having an outer perimeter wall 118. The fdter seal member 102 is along the outer perimeter wall 118.Preferably, the fdter seal member 102 is against the outer perimeter wall 118, to project radially from the end cap arrangement 96.

[0080] The fdter seal member 102 and the bypass seal member 90 have different outside shapes. In the example shown, the bypass seal member 90 is circular, while the fdter seal member 102 is non-circular.

[0081] The fdter seal member 102 can be a variety of shapes. By “shapes”, it is meant the shape of the perimeter. In one example, the fdter seal member 102 is egg-shaped.

[0082] In another example, the fdter seal member 102 is obround.

[0083] In another example, the fdter seal member 102 is racetrack shaped, having two curved sections joined by two straight sections.

[0084] In FIG. 8, the filter seal member 102 has a first curved section 120 and an opposite second curved section 122. The first curved section 120 and second curved section 122 have different radii of curvature. In general, the first curved section 120 has a smaller radius of curvature than the second curved section 122. That is, the curve of second curved section 122 is tighter than the curve of the first curved section 120.

[0085] For example, the radius of curvature of the first curved section 120 is between 0.5 and 0.8 of the radius of curvature of the second curved section 122. In another example, the radius of curvature of the first curved section 120 is between 0.6 and 0.7 of the radius of curvature of the second curved section 122. Straight sections 125, 126 extend between the first curved section 120 and second curved section 122.

[0086] Still in reference to FIG. 8, a longitudinal axis 124 extends through the first curved section 120 and second curved section 122. In this embodiment, the filter seal member 102 symmetrical about the longitudinal axis 124. In other embodiments, the filter seal member 102 can by asymmetrical about the axis 124.

[0087] In-tank filter assembly 20

[0088] In reference now to FIG. 3, an example embodiment of the element 30 installed in the tank 22, forming the in-tank filter assembly 20 is shown. As can be seen, in one example embodiment, the longitudinal axis 112 of the filter construction 60 and the longitudinal axis 110 of the bypass construction 74 can be perpendicular to the central axis 41 of the inlet 40.

[0089] The exit arrangement 82 is shown as being in communication with the bypass valve 52. When the exit arrangement 82 is filter screen 84, the bypass fluid flows through the bypass flow tube 76, is filtered by the screen 84, and then engages the bypass valve 52. When there is sufficient pressure in the bypass fluid, the force of the bypass fluid overcomes a spring 130 in the valve 52 to open a flow passage 132 through the valve 52, allowing the bypass fluid to flow into the tank interior 26.

[0090] In FIG. 3, it can be seen how the bypass seal member 90 circumscribes the bypass flow tube 76 and forms releasable seal 92 between the bypass flow tube 76 and the bypass housing 48. Further, it can be seen how the filter seal member 102 is secured to the end cap arrangement 96 and forms releasable seal 104 between the end cap arrangement 96 and the hydraulic tank 22.

[0091] In reference now to FIG. 4, the bypass housing 48 includes a surrounding wall 134 with a first open end 136 and an opposite second open end 138. The second open end 138 holds the bypass valve 52 therein. The first open end 136 is sized to receive, and does receive, the bypass flow tube 76. The surrounding wall 134 has a section 140 of through apertures 142 (FIG. 10) providing communication between an interior 144 of the bypass housing 48 and a remaining interior of the tank 22. The through apertures 142 ensure that a correctly sized bypass construction 74 is used with the in-tank filter assembly 20, because without the correctly sized bypass housing 48, inlet fluid will flow directly through the apertures 142, without flowing through the main filter construction 60.

[0092] The bypass seal member 90 forms the releasable seal 92 against an interior 144 of the surrounding wall 134 and axially between the bypass valve 52 and the section 140 of through apertures 142. The seal 92 prevents bypass flow from flowing through the apertures 142 and into the tank interior 26.

[0093] It can be helpful to ground the service cover member 36 to the tank 22. In FIG. 11, an optional metal strap 146 is illustrated grounding the cover member 36 to the tank 22. Advantages result from the arrangement of the in-tank assembly 20. The flow is from the interior volume 64 of the filter construction 60 to the outside. This enables cleaner servicing, in which contaminants and sediment are contained within the filter construction 60. Having the bypass construction 74 separate from and parallel with the filter construction 60 allows for use of the full vertical space of the tank 22 for the primary flow through the filter construction 60. Locating the bypass construction near the upper end cap arrangement 96 allows the bypass valve 52 to function cleanly and away from the bottom of the filter construction 60.

[0094] Example methods

[0095] In operation, fluid to be filtered enters the tank 22 through the inlet 40. The fluid then flows through the filter opening 98 in the end cap arrangement 96. The fluid flows into the interior volume 64 of the filter construction 60. The fluid then passes through the filter media 62 and then through the strainer 50, which filters the fluid. The filtered fluid then flows into a sump in the tank interior 26. When the fluid is demanded by equipment, the filtered fluid leaves the tank interior 26 through the outlet 42.

[0096] In the event of the filter media 62 becoming restricted / occluded, the fluid will flow through the bypass opening 100 of the end cap arrangement 96. When there is sufficientpressure in the bypass fluid, the force of the bypass fluid overcomes the spring 130 in the valve 52 to open flow passage 132 through the valve 52, allowing the bypass fluid to flow into the tank interior 26.

[0097] A method of servicing the in-tank assembly 20 is provided. The method includes removing the cover member 36 of the tank 22 to expose the service tank opening 32. Next, the filter element 30 is removed from the tank 22 through the opening 32. The step of removing includes breaking the filter seal 104 between the filter element 30 and the tank 22, wherein the seal 104 encloses both the filter construction 60 and the bypass construction 74. The step of removing also includes breaking the bypass seal 92 between the bypass construction 74 and the tank 22.

[0098] The step of removing the filter element 30 may include grasping the handle 114 extending from the filter element 30.

[0099] The above description represents example principles. Many embodiments can be made using these principles.

Claims

What is claimed is:

1. A removable and replaceable filter element for use in a hydraulic tank; comprising:(a) a filter construction having a tubular extension of filter media surrounding an open filter interior volume; the filter construction having a first end and an opposite second end and an outer perimeter;(b) a bypass construction positioned radially outside of the outer perimeter; the bypass construction having a bypass flow tube with an open tube interior volume; the bypass flow tube having a first end and an exit arrangement;(i) a bypass seal member circumscribing the bypass flow tube to form a seal between the bypass flow tube and the hydraulic tank, when the filter element is installed in the hydraulic tank;(c) an end cap arrangement at the first end of the filter construction and at the first end of the flow tube;(i) the end cap arrangement having a filter opening in communication with the open filter interior volume of the filter construction;(ii) the end cap arrangement having a bypass opening in communication with the open tube interior volume of the bypass flow tube; and(iii) a filter seal member secured to the end cap arrangement and enclosing both the filter construction and the bypass construction; the filter seal member positioned to form a seal between the end cap arrangement and the hydraulic tank, when the filter element is installed in the hydraulic tank.

2. The filter element of claim 1 further including a closed end cap at the second end of the filter construction.

3. The filter element of any one of claims 1 and 2, wherein the exit arrangement of the bypass construction includes a filter screen to filter bypass fluid.

4. The filter element of any one of claims 1-3 wherein:(a) the end cap arrangement has an outer perimeter wall; and(b) the filter seal member is along the outer perimeter wall.

5. The filter element of any one of claims 1-4 wherein:(a) the filter seal member is an o-ring seal member; and(b) the bypass seal member is an o-ring seal member.

6. The filter element of any one of claims 1-5, wherein a longitudinal axis of the bypass construction is parallel to the filter construction.

7. The filter element of any one of claims 1-6, wherein the filter seal member and the bypass seal member have different outside shapes.

8. The filter element of any one of claims 1-7, wherein the filter seal member is egg-shaped.

9. The filter element of any one of claims 1-7, wherein the filter seal member is obround.

10. The filter element of any one of claims 1-7, wherein the filter seal member is racetrack shaped, having two curved sections joined by two straight sections.

11. The filter element of any one of claims 1-7, wherein the filter seal member has a first curved section and an opposite second curved section; and the first curved section and second curved section have different radii of curvature.

12. The filter element of claim 11, wherein the radius of curvature of the first curved section is between 0.5 and 0.8 of the radius of curvature of the second curved section.

13. The filter element of claim 11, wherein the radius of curvature of the first curved section is between 0.6 and 0.7 of the radius of curvature of the second curved section.

14. The filter element of any one of claims 1-13, wherein the filter seal member has a first curved section and an opposite second curved section and a longitudinal axis extending through the first curved section and second curved section; the filter seal member being symmetrical about the longitudinal axis.

15. The filter element of any one of claims 1-13, wherein the filter seal member has a first curved section and an opposite second curved section and a longitudinal axis extending through the first curved section and second curved section; the filter seal member being asymmetrical about the longitudinal axis.

16. The filter element of any one of claims 1-15, wherein the bypass seal member is axially spaced from the filter seal member.

17. The filter element of claim 16, wherein the bypass seal member is axially spaced from the filter seal member by about 20-30 mm.

18. The filter element of any one of claims 1-17, wherein the filter media is pleated media.

19. The filter element of any one of claims 1-18, wherein bypass construction has an axial length less than 30% and greater than 5% of an axial length of the filter construction.

20. The filter element of any one of claims 1-18, wherein bypass construction has an axial length less than 25% and greater than 10% of an axial length of the filter construction.

21. The filter element of any one of claims 1-20, wherein the end cap arrangement includes a handle axially projecting therefrom, in a direction away from the filter construction.

22. The filter element of claim 21, wherein the handle comprises a grip bar bridging over the filter opening.

23. The filter element of any one of claims 1-22, wherein the bypass flow tube is integrally molded with the end cap arrangement.

24. The filter element of claim 3 and claim 23, wherein the filter screen is co-injected or comolded with the end cap arrangement and bypass flow tube.

25. An in-tank filter assembly comprising:(a) a tank for holding a filtered hydraulic fluid; the tank having an inlet with a central axis, an outlet, a filter opening, and a removable cover member over the filter opening; the tank also including a main filter housing and a bypass housing;(i) the bypass housing being radially outside of the main filter housing;(b) a bypass valve held by the bypass housing;(c) a filter element removably and replaceably seated in the tank; the filter element having a filter construction with a first longitudinal axis positioned in the main filter housing, and a bypass construction with a second longitudinal axis positioned in the bypass housing; and(d) a filter seal member enclosing both the filter construction and the bypass construction.

26. The filter assembly of claim 25, wherein the first and second longitudinal axes are perpendicular to the central axis of the inlet.

27. The filter assembly of any one of claims 25 and 26, wherein the filter element comprises:(a) the filter construction having a tubular extension of filter media surrounding an open filter interior volume; the filter construction having a first end and an opposite second end and an outer perimeter;(b) the bypass construction positioned radially outside of the outer perimeter; the bypass construction having a bypass flow tube with an open tube interior volume; the bypass flow tube having a first end and an exit arrangement; the exit arrangement being in communication with the bypass valve;(i) a bypass seal member circumscribing the bypass flow tube and forming a releasable seal between the bypass flow tube and the bypass housing;(c) an end cap arrangement at the first end of the filter construction and at the first end of the flow tube;(i) the end cap arrangement having a filter opening in communication with the open filter interior volume of the filter construction;(ii) the end cap arrangement having a bypass opening in communication with the open tube interior volume of the bypass flow tube; and(iii) the filter seal member being secured to the end cap arrangement and forming a seal between the end cap arrangement and the hydraulic tank.

28. The filter assembly of claim 27, wherein the bypass housing includes:(a) a surrounding wall with a first open end and an opposite second open end;(b) the second open end holding the bypass valve;(c) the first open end being sized to receive the bypass flow tube;(d) the surrounding wall having a section of through apertures providing communication between an interior of the bypass housing and a remaining interior of the tank; and(e) the bypass seal member forming the releasable seal against an interior of the surrounding wall and axially between the bypass valve and the section of through apertures.

29. The filter assembly of any one of claims 27 and 28, wherein the exit arrangement of the bypass construction includes a filter screen to filter bypass fluid.

30. The filter assembly of any one of claims 27-29, further including a strainer in the main filter housing and surrounding the filter construction.

31. The filter assembly of any one of claims 25-30, wherein the bypass construction is parallel to the filter construction.

32. The filter assembly of any one of claims 25-30, wherein the filter element is according to any one of claims 1-24.

33. A method of servicing an in-tank filter assembly; the method comprising:(a) removing the cover member of a hydraulic tank to expose a tank opening;(b) removing a filter element from the tank through the opening; the filter element having a filter construction and a bypass construction located radially outside of the filter construction; wherein the step of removing includes:(i) breaking a filter seal between the filter element and the tank, wherein the seal encloses both the filter construction and the bypass construction; and(ii) breaking a bypass seal between the bypass construction and the tank.

34. The method of claim 33, wherein the step of removing the filter element includes grasping a handle extending from the filter element.

35. The method of any one of claims 33 and 34, wherein the filter element comprises the filter element of any one of claims 1-24.

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