Filter element with integrated drain filter

Abstract

The technology disclosed herein relates in part to a filter assembly having a primary media assembly and a secondary media assembly in fluid communication with the primary media assembly. The filter assembly outlet is downstream of the secondary media assembly. A filtration passage extends through the primary media assembly, the secondary media assembly, and the filter assembly outlet. A discharge passage extends through the secondary media assembly and the filter assembly outlet, wherein the discharge passage avoids the primary media assembly.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 870,456, filed on July 3, 2019, and U.S. Provisional Application No. 62 / 951,608, filed on December 20, 2019, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0002] The present disclosure relates generally to filter elements. More particularly, the present disclosure relates to a filter element with an integrated exhaust filter. Background Art

[0003] Typically in hydraulic systems, the case drain flow path is separate from the implement return flow path. This is because the pump and motor case pressures cannot tolerate the high back pressure caused by the return line with a relatively high bypass valve setting. Therefore, the case drain flow usually requires a separate flow path that has a lower back pressure and a lower bypass valve setting than the return flow path. Summary of the invention

[0004] Some embodiments disclosed herein relate to a filter element. The filter element has a filter media assembly having a first media end and a second media end. The filter element has a central passageway from the first media end to the second media end. A first end cap is coupled to the first media end. A second end cap is coupled to the second media end. A discharge passage extends through the first end cap, and a filter passage extends from the central passageway through the filter media assembly. The discharge passage is separated from the filter passageway in the first end cap.

[0005] In some such embodiments, the exhaust passage extends through the central channel and the second end cap. Additionally or alternatively, the exhaust passage has an exhaust passage inlet extending through the first end cap and an exhaust passage outlet extending through the first end cap. Additionally or alternatively, the filter passage further extends through the first end cap.

[0006] Additionally or alternatively, the flow tube is disposed in the central passage, wherein the flow tube contains a discharge passage. Additionally or alternatively, the flow tube is coupled to the first end cap around the discharge passage. Additionally or alternatively, the flow tube is coupled to the second end cap around the discharge passage. Additionally or alternatively, the flow tube is separate from the first end cap.

[0007] Additionally or alternatively, the discharge passage has a discharge passage inlet extending through the first end cap and a discharge passage outlet extending through the second end cap. Additionally or alternatively, the element has a discharge media assembly defining a portion of the discharge passage, wherein the discharge media assembly is the discharge passage outlet. Additionally or alternatively, the discharge passage outlet extends radially outward from the filter element. Additionally or alternatively, the flow tube defines the discharge passage outlet.

[0008] Additionally or alternatively, the filter passage inlet is radially positioned between the flow tube and the filter media assembly. Additionally or alternatively, the second end cap blocks the filter passage in the central channel. Additionally or alternatively, the first end cap is configured to be positioned vertically above the second end cap. Additionally or alternatively, the first end cap is configured to be positioned vertically below the second end cap. Additionally or alternatively, the filter passage extends through the first end cap and the second end cap.

[0009] Some embodiments of the technology disclosed herein relate to a filter element. A filter media assembly has a first media end and a second media end, and a central passage from the first media end to the second media end. A first end cap is coupled to the first media end. The first end cap defines a first end cap opening. The second end cap is coupled to the second media end. The second end cap defines a second end cap opening. The filter element has a flow tube having a first tube end and a second tube end. The flow tube defines a first tube opening on the first tube end, and a central opening extending from the first tube end to the second tube end. The flow tube is positioned in the central passage. The flow tube extends between the first end cap opening and the second end cap opening. The flow tube and the filter media assembly define a first channel opening separated from the central opening, whereby the filter element has a filter passage and a discharge passage. The filter passage passes through the filter media assembly from the first channel opening via the central passage. The first channel opening defines an inlet to the filter passage. The discharge passage is along the central opening of the flow tube.

[0010] In some such embodiments, the flow tube and the second end cap form a seal around the central opening, and wherein the flow tube and the first end cap are separated. Additionally or alternatively, the flow tube extends from the second end cap in a longitudinal direction beyond the first end cap. Additionally or alternatively, the flow tube forms a seal with the first end cap around the central opening, and the flow tube forms a seal with the second end cap around the central opening. Additionally or alternatively, the outer diameter of the first channel opening is greater than the outer diameter of the first tube opening. Additionally or alternatively, the filter element has an exhaust filter element having an exhaust filter inlet, wherein the flow tube is connected to the exhaust filter element around the exhaust filter inlet. Additionally or alternatively, the exhaust filter element is connected to the second end cap. Additionally or alternatively, the first channel opening extends circumferentially around the first tube opening. Additionally or alternatively, the first channel opening is a series of opening segments.

[0011] Some embodiments disclosed herein relate to a filter assembly having a primary filter element and a secondary filter element. The primary filter element has a primary media assembly having a first media end, a second media end, and a central passage from the first media end to the second media end. A first end cap is coupled to the first media end, and a second end cap is coupled to the second media end. A filter passage extends through the first end cap, the central passage, and the primary media assembly. The filter passage has a filter passage inlet through the first end cap and an outlet through the primary media assembly. The secondary filter element has a secondary media assembly having a third media end, a fourth media end, and a cavity extending from the third media end to the fourth media end. A third end cap is coupled to the third media end of the secondary media assembly. The third end cap has a third end cap opening, wherein the cavity and the third end cap opening are configured to receive the primary filter element. The fourth end cap is coupled to the fourth end of the secondary media assembly. The filter assembly defines a discharge passage extending through the secondary filter element. The discharge passage is separated from the filter passage within the primary media assembly.

[0012] In some such embodiments, the discharge passage extends through the first end cap, the second end cap and the central channel. Additionally or alternatively, the third end cap has an inner circumferential sealing surface configured to form a seal to the outer circumferential sealing surface of the first end cap. Additionally or alternatively, the assembly defines a gap between the first end cap and the third end cap. Additionally or alternatively, the gap between the first end cap and the third end cap defines a discharge passage inlet. Additionally or alternatively, a flow tube is disposed in the central channel, wherein the flow tube contains the discharge passage. Additionally or alternatively, a filter passage inlet is defined between the first end cap and the flow tube. Additionally or alternatively, the flow tube is coupled to the first end cap. Additionally or alternatively, the fourth end cap forms a fluid barrier across the cavity. Additionally or alternatively, the filter passage extends through the second end cap. Additionally or alternatively, the filter assembly has a spacer extending between the fourth end cap and the second end cap in a longitudinal direction. Additionally or alternatively, the fourth end cap and the second end cap define a flow gap that is a portion of the discharge passage from the second end cap to the secondary media assembly.

[0013] Additionally or alternatively, the assembly has an exhaust filter element having an exhaust filter inlet, wherein the exhaust filter element is along an exhaust passage and the exhaust filter element is an outlet of the exhaust passage. Additionally or alternatively, the exhaust filter is coupled to the second end cap and the fourth end cap. Additionally or alternatively, the exhaust filter element has an exhaust media assembly in fluid communication with the exhaust filter inlet, wherein the primary media assembly has a higher particle filtration efficiency than the exhaust media assembly. Additionally or alternatively, the primary media assembly has a higher particle filtration efficiency than the secondary media assembly. Additionally or alternatively, the exhaust passage has an exhaust passage inlet defined by the first end cap. Additionally or alternatively, the exhaust passage has an exhaust passage inlet defined by a flow tube. Additionally or alternatively, the filter passage inlet extends circumferentially around the exhaust passage inlet.

[0014] Some embodiments relate to a system having a filter cover assembly having a filter passage. A primary filter element is configured to be removably coupled to the filter cover assembly. The primary filter element has a first end cap, a second end cap, and a primary media assembly extending from the first end cap to the second end cap. The primary filter element has a first central channel in fluid communication with the filter passage. A discharge filter element is coupled to the filter cover assembly. The discharge passage is configured to extend to the discharge filter element and avoid the primary media assembly.

[0015] In some such embodiments, the filter cover assembly defines a portion of the discharge passage that is isolated from the filter passage. Additionally or alternatively, the discharge passage is configured to bypass the primary media assembly through the first central channel. Additionally or alternatively, the system has a secondary filter element having a third end cap, a fourth end cap, and a secondary media assembly extending from the third end cap to the fourth end cap. The secondary filter element has a second central channel extending from the third end cap through the secondary media assembly, wherein the second central channel is configured to receive the primary filter element.

[0016] Additionally or alternatively, the discharge passage extends to a gap defined between the primary media assembly and the secondary media assembly. Additionally or alternatively, the third end cap is configured to form a seal with the first end cap. Additionally or alternatively, the discharge filter element is a secondary filter element. Additionally or alternatively, the system has a flow tube extending through the first central channel. Additionally or alternatively, the discharge passage extends through the third end cap. Additionally or alternatively, the discharge passage extends through the fourth end cap. Additionally or alternatively, the flow tube is coupled to the filter cover assembly around the discharge passage. Additionally or alternatively, the flow tube is coupled to the filter cover assembly around the bypass passage. Additionally or alternatively, the discharge filter element is coupled to the second end cap.

[0017] Additionally or alternatively, the filter cover assembly further has a fill port in fluid communication with the discharge passage, and a removable cover disposed on the fill port. Additionally or alternatively, the system has a bypass valve disposed between the discharge passage and the filter passage. Additionally or alternatively, the filter cover assembly includes a filter cover and a filter head, wherein the filter cover and the filter head are coupled. Additionally or alternatively, the filter cover assembly has a filter cover and a filter head structure, wherein the filter head structure is defined by a tank and the filter cover is coupled to the filter head structure.

[0018] Some embodiments relate to a filter assembly. The assembly has a primary media assembly. A secondary media assembly is in fluid communication with the primary media assembly. The filter assembly outlet is downstream of the secondary media assembly. A filtration passage extends through the primary media assembly, the secondary media assembly, and the filter assembly outlet. A discharge passage extends through the secondary media assembly and the filter assembly outlet. The discharge passage avoids the primary media assembly.

[0019] In some such embodiments, a bypass passage selectively extends from the filter passage through the secondary media assembly and the filter assembly outlet, wherein the bypass passage bypasses the primary media assembly. Additionally or alternatively, the secondary media assembly is positioned downstream of the primary media assembly in the filter passage. Additionally or alternatively, the system has a primary filter element having a primary media assembly. The primary media assembly has a first media end, a second media end, and a central passage from the first media end to the second media end. A first end cap is coupled to the first media end, and a second end cap is coupled to the second media end.

[0020] Additionally or alternatively, the exhaust passage extends through the first end cap and the second end cap of the primary filter element. Additionally or alternatively, the system has a secondary filter element having a secondary media assembly having a third media end and a fourth media end and having a cavity extending from the third media end to the fourth media end. The third end cap is coupled to the third media end of the secondary media assembly. The third end cap has a third end cap opening, wherein the cavity and the third end cap opening are configured to receive the primary filter element. The fourth end cap is coupled to the fourth end of the secondary media assembly.

[0021] Additionally or alternatively, the discharge passage extends through a fourth end cap of the secondary filter element. Additionally or alternatively, the discharge passage does not extend through the primary media assembly. Additionally or alternatively, the third end cap has an inner circumferential sealing surface that is configured to form a seal with an outer circumferential sealing surface of the first end cap. Additionally or alternatively, the third end cap and the first end cap define a discharge passage therebetween. Additionally or alternatively, the system has a fill port passage extending through the secondary media assembly and the filter assembly outlet, wherein the fill port passage avoids the primary media assembly. Additionally or alternatively, the fill port passage and the bypass passage merge into the fluid flow passage. Additionally or alternatively, the fill port passage and the bypass passage merge with the discharge passage.

[0022] Some embodiments relate to a system having a tank body that defines a fluid cavity, a fluid outlet, a filter assembly opening, a fluid return inlet, and a drain tank body inlet. The filter assembly is disposed in the fluid cavity and coupled to the tank body around the filter assembly opening. A filter cap assembly is coupled to the filter assembly and the tank body. A filter passage extends from the fluid return inlet through the tank body to the filter assembly. A drain conduit extends from the drain tank body inlet through the fluid cavity to the filter assembly. A drain passage is defined from the drain tank body inlet through the drain conduit to the filter assembly.

[0023] In some such embodiments, the filter cover assembly is positioned toward a first end of the tank body, and a drain tank body inlet is defined toward an opposite end of the tank body. Additionally or alternatively, the tank body defines a top end and a bottom end, and the drain tank body inlet is defined toward the bottom end of the tank body. Additionally or alternatively, the filter cover assembly defines a fluid return inlet. Additionally or alternatively, the tank body has a top end and a bottom end, and the tank body defines a fluid return inlet toward the bottom end. Additionally or alternatively, the filter assembly includes a primary media assembly and a secondary media assembly downstream of the primary media assembly.

[0024] Additionally or alternatively, the filter passage extends from the fluid return inlet through the primary media assembly and through the secondary media assembly. Additionally or alternatively, the exhaust passage bypasses the primary media assembly and extends through the secondary media assembly. Additionally or alternatively, the filter cap assembly has a filter cap and a filter head, wherein the filter cap and the filter head are coupled. Additionally or alternatively, the filter cap assembly has a filter cap and a filter head structure, wherein the filter head structure is defined by the canister and the filter cap is coupled to the filter head structure.

[0025] Some embodiments disclosed herein relate to a filter assembly. The filter assembly has a primary media assembly. A secondary media assembly is in fluid communication with the primary media assembly. A filter passage outlet is downstream of the secondary media assembly. The filter passage extends through the primary media assembly, the secondary media assembly, and the filter passage outlet. A discharge passage outlet is configured to merge with the filter passage outlet. The discharge passage extends to the discharge passage outlet. The discharge media assembly is disposed across the discharge passage. The fluid flow path selectively extends to the discharge passage upstream of the discharge media assembly.

[0026] In some such embodiments, the fluid flow passage is a bypass passage that selectively extends from the fluid flow passage to the discharge passage, wherein the bypass passage is upstream of the primary media assembly. Additionally or alternatively, the fluid flow passage is a fill port passage that can be selectively opened by a user. Additionally or alternatively, the secondary media assembly is positioned downstream of the primary media assembly in the filter passage. Additionally or alternatively, the filter assembly has a primary filter element having a primary media assembly. The primary media assembly has a first media end, a second media end, and a central passage from the first media end to the second media end. The first end cap is coupled to the first media end, and the second end cap is coupled to the second media end.

[0027] Additionally or alternatively, the filter assembly has a secondary filter element having a secondary media assembly. The secondary media assembly has a third media end and a fourth media end, and a cavity extending from the third media end to the fourth media end. A third end cap is coupled to the third media end of the secondary media assembly. The third end cap has a third end cap opening, wherein the cavity and the third end cap opening are configured to receive the primary filter element. A fourth end cap is coupled to the fourth end of the secondary media assembly.

[0028] Additionally or alternatively, the third end cap has an inner circumferential sealing surface configured to form a seal with an outer circumferential sealing surface of the first end cap. Additionally or alternatively, the bypass passage selectively extends to the secondary media assembly and bypasses the primary media assembly. Additionally or alternatively, the fill port passage extends through the secondary media assembly and the filter passage outlet, wherein the fill port passage avoids the primary media assembly.

[0029] The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of the illustrative embodiments will become apparent and appreciated by referring to the following detailed description of exemplary embodiments and the claims in view of the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of an example filter element consistent with the technology disclosed herein.

[0031] Figure 2 yes Figure 1 An example cross-sectional view of an example filter element.

[0032] Figure 3 is a cross-sectional view of another example filter element consistent with the techniques disclosed herein.

[0033] Figure 4 is a cross-sectional view of an example filter assembly consistent with the techniques disclosed herein.

[0034] Figure 5 is a cross-sectional view of another example filter assembly consistent with the techniques disclosed herein.

[0035] Fig. 6A are schematic diagrams of some example systems consistent with the techniques disclosed herein.

[0036] Figure 6B are schematic diagrams of some other example systems consistent with the techniques disclosed herein.

[0037] Figure 7 is a perspective view of an example system consistent with the techniques disclosed herein.

[0038] Figure 8 yes Figure 7 A first cross-sectional view of an example system.

[0039] Fig. 9 yes Figure 7 A second cross-sectional view of an example system.

[0040] Fig.10 is a cross-sectional view of another example system consistent with the techniques disclosed herein.

[0041] Fig.11 is a cross-sectional view of another example filter assembly consistent with the techniques disclosed herein.

[0042] Fig.12 is a perspective view of an example tank system consistent with some embodiments.

[0043] Fig.13 is with Fig.12 Exploded view of a consistent example system.

[0044] Fig.14 is with Fig.12 A first cross-sectional view of a consistent example system.

[0045] Fig.15 is with Fig.12 A second cross-sectional view of a consistent example system.

[0046] Fig.16is a cross-sectional view of another example filter element.

[0047] Fig.17 yes Fig.16 A perspective view of an example filter element.

[0048] Fig.18 is with Figure 16 to Figure 17 Consistent example filter component.

[0049] Fig.19 is with Fig.18 Consistent example system.

[0050] Fig. 20 is with Fig.18 Another example of a consistent system.

[0051] Fig.21 is a partial cross-sectional perspective view of another example system.

[0052] The present technology may be more fully understood and appreciated considering the following description of various embodiments in conjunction with the accompanying drawings.

[0053] The drawings are presented primarily for clarity and are therefore not necessarily drawn to scale. In addition, various structures / components (including, but not limited to, fasteners, electrical components (wiring, cables, etc.), etc.) may be illustrated diagrammatically or removed from some or all views to better illustrate aspects of the depicted embodiments, or the inclusion of such structures / components is not necessary for understanding the various exemplary embodiments described herein. However, the lack of illustration / description of such structures / components in a particular drawing shall not be construed as limiting the scope of the various embodiments in any way. DETAILED DESCRIPTION

[0054] Figure 1 is an example filter element 100 consistent with the techniques disclosed herein. Figure 2 yes Figure 1 1. An example cross-sectional view of an example filter element 100. The filter element 100 has a filter media assembly 110 defining a central passage 116, a first end cap 120 coupled to a first media end 112 of the filter media assembly 110, a second end cap 130 coupled to a second media end 114 of the filter media assembly 110, and a flow tube 140 disposed in the central passage 116. The filter element 100 defines a filter passage 104 and a drain passage 102, wherein the filter passage 104 extends through the filter media assembly 110 and the drain passage 102 bypasses / avoids (does not extend through) the filter media assembly 110.

[0055] The filter media assembly 110 is generally configured to filter a fluid. In some embodiments, the filter media assembly 110 is configured to filter a hydraulic fluid. The first end 112 of the filter media assembly 110 is coupled to the first end cap 120, and the second end 114 of the filter media assembly 110 is coupled to the second end cap 130. The filter media assembly 110 generally has a cylindrical arrangement. The filter media assembly 110 defines a central channel 116 extending from the first media end 112 to the second media end 114. In the current example, the central channel 116 defines the filter passage 104 and the exhaust passage 102.

[0056] The filter media assembly 110 and the central channel 116 share a central axis x, wherein the central axis x extends in the longitudinal direction. The length of the filter media assembly 110 in the longitudinal direction can vary. In some embodiments, the length of the filter media assembly 110 is greater than 3.5 inches (8.9 cm). In some embodiments, the length L of the filter media assembly 110 is less than 40 inches (101.6 cm). In some embodiments, the length L of the filter media assembly 110 ranges from about 4 to 40 inches (10.2 to 101.6 cm), 15 to 30 inches (38.1 to 76.2 cm), or 10 to 25 inches (25.4 to 63.5 cm).

[0057] The filter media assembly 110 has a filter media 111. The filter media 111 can be constructed of various materials and combinations of materials suitable for filtering fluids, such as hydraulic fluids. In some embodiments, the filter media 111 is constructed of fibers. In various embodiments, the filter media 111 is pleated. In some other embodiments, the filter media is a sheet of media wrapped in a spiral configuration around a longitudinal axis.

[0058] In some embodiments where filter media 111 is pleated, such as in the depicted example, filter media 111 is a media sheet having outer circumferential boundaries 111a ( Figure 2 ) and a second set of pleat folds 119 that cumulatively define an inner circumferential limit 111b of the filter media 111. In the current example, the inner circumferential limit 111b of the filter media 111 is the inner radial boundary 119 (which is also the pleat fold 119) of the filter media assembly 110. However, in some embodiments, the structural support may abut the filter media 111 along its inner boundary, and such a structural support would define the inner radial boundary of the filter media assembly 110. Indeed, in the current example where the structural support 113 surrounds the filter media 111, the structural support 113 defines the outer radial boundary 118 of the filter media assembly 110.

[0059] The structural support 113 is generally configured to provide structural support to the filter medium 111 to prevent the filter medium 111 from bursting when subjected to the forces generated by the flow of liquid therethrough. The structural support 113 generally does not exhibit particle filtration efficiency and is more permeable than the filter media assembly 110. Here, the structural support 113 can be a tubular screen surrounding the outer boundary of the filter medium 111. In some embodiments, the (multiple) structural support 113 is omitted. As described above, in some examples, the structural support is adjacent to the inner boundary of the filter medium 111 within the central channel 116. In some embodiments, the structural support is adjacent to the filter medium 111 along the inner and outer boundaries of the filter medium 111.

[0060] The first end cap 120 is generally configured to retain the first media end 112 of the filter media assembly 110 and define a portion of the filter passage 104 that passes through the filter media assembly 110. The first end cap 120 is also configured to define a portion of the discharge passage 102, and thus, the discharge passage 102 extends through the first end cap 120. The discharge passage 102 is separated from the filter passage 104 in the first end cap 120, which means that: in the first end cap 120, there is a fluid barrier (here, the flow tube 140) between at least a portion of the discharge passage 102 and the filter passage 104. In some other embodiments, the discharge passage 102 is outside the first end cap, which separates the discharge passage from the filter passage in the first end cap. The first end cap 120 is connected to the first media end 112. In the current example, the first end cap 120 defines a first end cap opening 121 (at Figure 2 1 ), the first end cap opening extends in a longitudinal direction from the exterior of the filter assembly 101 to the central passage 116. In the current example, the first end cap opening 121 is a combination of a plurality of openings, namely a first tube opening 141 and a first passage opening 122 having a series of discrete openings, which are opening segments 122a, 122b, 122c, 122d, as will be described in more detail below.

[0061] As best seen in FIG. 2 , the first end cap 120 has a first media potting structure 123 configured to receive the first end 112 of the filter media assembly 110. The first media potting structure 123 is defined by an annular surface 124 that abuts the first end 112 of the filter media assembly 110, an inner tubular flange 125, and an outer tubular flange 126. The inner tubular flange 125 extends longitudinally from the annular surface 124 into the central passage 116. The inner tubular flange 125 abuts the inner radial boundary 119 of the filter media assembly 110. The outer tubular flange 126 extends longitudinally from the annular surface 124 above the outer radial boundary 118 of the first end 112 of the filter media assembly 110. In various embodiments, the first media potting structure 123 and the first end 112 of the filter media assembly 110 are bonded with an adhesive / sealant disposed in the first media potting structure 123.

[0062] The first end cap 120 has an outer circumferential sealing surface 128 about the longitudinal axis x, which is configured to form a seal with a filter system component, which will be described in more detail below. The outer circumferential sealing surface 128 shares the central axis x of the filter media assembly 110 and the central channel 116. The outer circumferential sealing surface 128 can be a circumferential cavity configured to receive an elastomeric component (such as, an o-ring 127). In some embodiments, the circumferential cavity is discontinuous, while in other embodiments, the circumferential cavity is continuous.

[0063] The second end cap 130 is generally configured to hold the second media end 114 of the filter media assembly 110 and define a portion of the filter passage 104 through the filter media assembly 110. In the current example, the second end cap 130 is configured to define a portion of the discharge passage 102, and thus, the discharge passage 102 extends through the second end cap 130. The discharge passage 102 is separated from the filter passage 104 in the second end cap 130. The second end cap 130 is configured to block the central passage 116 radially outward from the flow tube 140. The second end cap 130 is coupled to the second media end 114 and defines a second end cap opening 136 (wherein "second end cap" is used to modify the term "opening" because the opening is defined by the second end cap). As will be discussed below, the second end cap opening 136 can define a filter element outlet. In the current example, the second end cap 130 has an inner tubular flange 138 that extends longitudinally into the central passage 116. The inner tubular flange 138 surrounds the second end cap opening 136. The inner tubular flange 138 may be considered a segment of the flow tube. In some embodiments, the second end cap 130 does not have an inner tubular flange 138 .

[0064] As in Figure 2As best seen in FIG. 1 , the second end cap 130 has a second media potting structure 134 configured to receive the second end 114 of the filter media assembly 110. The second media potting structure 134 is defined by an annular surface 132 that abuts the second end 114 of the filter media assembly 110 and an outer tubular flange 133. The outer tubular flange 133 extends longitudinally from the annular surface 132 above the outer radial boundary 118 of the second end 114 of the filter media assembly 110. In various embodiments, the second media potting structure 134 and the second end 114 of the filter media assembly 110 are bonded with an adhesive / sealant disposed in the second media potting structure 134.

[0065] The flow tube 140 is generally configured to define a portion of the exhaust passage 102. The flow tube 140 is generally configured to fluidly separate the exhaust passage 102 from the filter passage 104 through the filter element 100. The flow tube 140 has a first tube end 142 and a second tube end 144. The first tube end 142 defines a first tube opening 141, and the flow tube 140 defines a central opening 146 extending from the first tube end 142 to the second tube end 144. The first tube end 142 has a sealing structure 148 configured to form a seal with a system component. The sealing structure can be an o-ring or other sealing material disposed around the first tube end 142.

[0066] The flow tube 140 and its central opening 146 extend in the longitudinal direction. In the current example, the central opening 146 forms an elongated cylinder, but in other examples, the central opening can be tapered or formed in other shapes. In the current example, the flow tube 140 is positioned in the central passage 116. Specifically, the flow tube 140 is centrally positioned to the central passage 116.

[0067] The flow tube 140 is sealably coupled to the second end cap 130 about the second end cap opening 136. In particular, the flow tube 140 and the inner tubular flange 138 of the second end cap 130 engage each other to form a radial seal about the second end cap opening 136. Although in the present example, the second tube end 144 of the flow tube 140 frictionally and sealably receives the inner tubular flange 138 of the second end cap 130, in some embodiments, the flow tube 140 can be formed as an integral, unitary structure with the second end cap 130, such as where the flow tube 140 and the second end cap 130 are formed by a single molding operation. The inner tubular flange 138 can define a portion of the flow tube 140.

[0068] In an example consistent with the current embodiment, the first tube end 142 of the flow tube 140 is formed by the end cap tube 129 of the first end cap 120. The end cap tube 129 can be considered as a first section of the flow tube 140 that is frictionally and sealably coupled to the second section of the flow tube 140. The first section of the flow tube 140 and the second section of the flow tube 140 engage each other and form a radial seal around the central opening 146. The end cap tube 129 extends longitudinally outward from the first end cap 120. In some embodiments, the first end cap 120 does not have the end cap tube 129.

[0069] In some embodiments, the flow tube is connected to the first end cap (an example of which is shown in FIG. Figure 3 140 and described below). In some other embodiments, the flow tube is a single, integral structure that is separate from the first end cap but coupled to the first end cap. In some further embodiments, the first end cap defines a larger section of the flow tube 140. In yet further embodiments, the first end cap and the flow tube are a single, integral component. In some embodiments, the flow tube is a detachable and replaceable component of the filter element. In such embodiments, any known configuration for forming a detachable, sealed connection with the second end cap 130 (and the first end cap 120, if appropriate for the particular configuration) can be used.

[0070] The flow tube 140 defines a first channel opening 122. The first channel opening 122 is configured to be fluidically separated from the first tube opening 141 by the flow tube 140. The flow tube 140 is generally constructed of a material that is impermeable to fluid flow. The first tube opening 141 is in direct fluid communication with the central opening 146 of the flow tube 140. The first channel opening 122 is in direct fluid communication with the central channel 116 of the filter media assembly 110. Thus, the filter element 100 defines a filter passage 104 that extends from the first channel opening 122 through the filter media assembly 110 via the central channel 116. The first channel opening 122 can define a filter passage inlet to the filter element 100. The filter element 100 also defines a discharge passage 102 from the first tube opening 141 to the second end cap opening 136. The first tube opening 141 can define a discharge passage inlet to the filter element 100. The second end cap opening 136 can define a discharge passage outlet of the filter element 100.

[0071] In the present example, the first passage opening 122 is a plurality of opening segments 122a, 122b, 122c, 122d defined between the first end cap 120 and the flow tube 140. The first end cap 120 has a plurality of brackets 115 extending radially from the flow tube 140 to the annular surface 124. The plurality of brackets 115 separate each of the opening segments 122a, 122b, 122c, 122d that cumulatively define the first passage opening 122. The plurality of opening segments 122a, 122b, 122c, 122d are defined around the central axis x. The first passage opening 122 extends circumferentially around the first tube opening 141. Thus, the outer diameter D1 of the first passage opening 122 is greater than the outer diameter D2 of the first tube opening 141. The outer diameter D1 of the first passage opening 122 may correspond to the inner diameter of the filter media assembly 110.

[0072] The surface area of ​​the filter medium 111, the permeability of the filter medium 111, and the cross-sectional flow area of ​​the central passage 116 in a plane perpendicular to the central axis x are example factors that determine the maximum flow rate that the filter element is configured to accommodate for effective filtration. In the current example, the cross-sectional flow area 116b of the filter passage 104 in the central passage 116 is the area of ​​the annulus defined by the cross-sectional area 116a of the central passage 116 minus the cross-sectional area 140a of the flow tube 140 across the central passage 116. It should be noted that in Figure 2 In the example of the cross-sectional area, these cross-sectional areas are represented by lines representing example planes through which the cross-sectional area would extend in a direction perpendicular to the central axis x. In some embodiments, where the filter element 100 is designed to filter hydraulic fluid at a flow rate of 300 L / min, the cross-sectional flow area 116b of the filter passage 104 is at least 1.7 in. 2 In some such examples, if the filter passage 104 has less than 1.7 in. in the central passage 116 2 If the cross-sectional flow area is too large, undesirable back pressure may be generated in the system in which the filter element 100 is employed.

[0073] It will be appreciated that the cross-sectional area 140a of the flow tube 140 across the central passage 116 affects the liquid flow capacity of the filter passage 104 within the central passage 116. The cross-sectional area of ​​the flow tube across the central opening is generally not limited. However, in some embodiments, the maximum cross-sectional area 140a of the flow tube across the central opening is 4 in. 2 In addition, the cross-sectional area of ​​the flow tube 140 across the inner dimension D3 (in a plane perpendicular to the central axis x) is generally sized to accommodate the maximum expected liquid flow rate along the discharge passage 102. In some embodiments, the cross-sectional area of ​​the flow tube 140 across its inner dimension D3 is at least 0.1 in. 2In some embodiments, the cross-sectional area of ​​the flow tube 140 across its inner dimension D3 is at least 0.3 in. 2 The flow tube 140 may have an inner dimension D3 ranging from 0.3 in. 2 Up to 4in 2 The cross-sectional area.

[0074] The flow tube 140 generally extends between the first end cap and the second end cap 130. In this example, the flow tube 140 extends from the first end cap 120 to the second end cap 130. More specifically, the flow tube 140 extends from the second end cap 130 to the first end cap 120 and beyond the first end cap 120 in a longitudinal direction. In some examples, the flow tube extends from the second end cap toward the first end cap. In such examples, the flow tube can extend to a longitudinal position between the first end cap and the second end cap.

[0075] The drain passage 102 is generally configured to be separate from the filter passage 104 within the filter media assembly 110. In various embodiments, the drain passage extends through at least one of the first end cap 120 and the second end cap 130. In the current example, the drain passage extends through both the first end cap 120 and the second end cap 130. In the current example, the drain passage extends through the first end cap 120, the second end cap 130, and the central passage 116.

[0076] Figure 3 2 is a cross-sectional view of another example filter element 200 consistent with the techniques herein. The filter element 200 has a filter media assembly 210 defining a central passage 216, a first end cap 220 coupled to a first media end 212 of the filter media assembly 210, a second end cap 230 coupled to a second media end 214 of the filter media assembly 210, and a flow tube 240 disposed in the central passage 216. The filter element 200 defines a filter passage 204 and a drain passage 202, wherein the filter passage 204 extends through the filter media assembly 210 and the drain passage 202 avoids the filter media assembly 210.

[0077] The various features and functions of the current example filter element 200 are similar to those described above with respect to Figure 1 and Figure 2 The discussion of filter elements is generally consistent with the discussion of filter elements (except where such features and functions are inconsistent with the current description).

[0078] The filter media assembly 210 defines a central passage 216 extending from the first media end 212 to the second media end 214. The central passage 216 contains a portion of the filter passage 204 and a portion of the drain passage 202. The drain passage 202 is generally separate from the filter passage 204 within the filter media assembly 210. The drain passage 202 is separate from the filter passage 204 in the central passage 216. The first end cap 220 defines a first end cap opening 221 containing the filter passage 204 and a portion of the drain passage 202. The drain passage 202 is separate from the filter passage 204 in the first end cap 220. The second end cap 230 defines the filter passage 204 and a portion of the drain passage 202. The drain passage 202 is separated from the filter passage 204 by the second end cap 230. The second end cap 230 defines a second end cap opening 236 and blocks the central passage 216 radially outward from the second end cap opening 236 (and the flow tube 240) at the second media end 214. Such a configuration prevents the fluid in the filter passage 204 from flowing through the second end cap 230 .

[0079] The flow tube 240 is sealably coupled to the second end cap 230 about the second end cap opening 236 toward a second tube end 244 of the flow tube 240. In some embodiments, the flow tube 240 is detachably coupled to the second end cap 230. The first tube end 242 of the flow tube 240 defines a first tube opening 241 in direct fluid communication with the central opening 246 of the flow tube 240. The first tube opening 241 may be a discharge passage inlet relative to the filter element.

[0080] The first channel opening 222 is defined by the flow tube 240 and the filter media assembly 210. More specifically, the first channel opening 222 is defined by the flow tube 240 and the first end cap 220 at the first end 212 of the filter media assembly 210. The first channel opening 222 can define a filter passage entrance relative to the filter element. In the current example, the first channel opening 222 is a single opening that extends circumferentially around the flow tube 240. Thus, similar to Figure 1 and Figure 2 In the example of FIG. 2 , the outer diameter of the first channel opening 222 , which is the inner diameter of the filter medium assembly 210 , is greater than the outer diameter of the first tube opening 241 .

[0081] In the present example, the second end cap 230 does not have Figure 2236 . The flow tube 240 is sealably coupled to the inner tubular flange (138) of the flow tube as in the example. In this example, the flow tube 240 and the first end cap 220 are separated. The flow tube 240 extends between the first end cap 220 and the second end cap 230. More specifically, the flow tube 240 extends from the second end cap 230 in the longitudinal direction beyond the first end cap 220. However, in some other embodiments, the flow tube may extend to a longitudinal position between the first end cap and the second end cap. In this example, the flow tube 240 extends from the second end cap 230 to the first end cap 220 in the longitudinal direction and extends beyond the first end cap 220. Also in this example, the flow tube 240 extends longitudinally outward from each of the first end cap 220 and the second end cap 230. The flow tube 240 is sealably coupled to the second end cap 230 around the second end cap opening 236. A seal 238 may be disposed between the flow tube 240 and the second end cap 230.

[0082] In an example consistent with the presently depicted embodiment, the filter element 200 has an exhaust filter element 250 that partially defines the exhaust passage 202. The exhaust filter element 250 is configured to filter the fluid passing through the exhaust passage 202. The exhaust filter element 250 is in fluid communication with the central opening 246 of the flow tube 240. In particular, the exhaust filter element 250 has an exhaust media assembly 252 that is in fluid communication with the central opening 246 of the flow tube 240. The exhaust media assembly 252 is configured to filter the fluid flowing through the exhaust passage 202.

[0083] The exhaust filter element 250 is sealably coupled to the flow tube 240. The exhaust filter element 250 can be sealably coupled to the second end cap 230. The exhaust filter element 250 can have a variety of different configurations. In the current example, the exhaust media assembly 252 is disposed about the central axis x and defines an upstream volume 251 about the central axis x. The exhaust media assembly 252 extends between the first exhaust filter end cap 254 and the second exhaust filter end cap 256 in the longitudinal direction. The first exhaust filter end cap 254 defines a first potting structure 259 configured to receive the first end of the exhaust media assembly 252, and the second exhaust filter end cap 256 defines a second potting structure 257 configured to receive the second end of the exhaust media assembly 252. The first exhaust filter end cap 254 defines an exhaust filter inlet 255 to the exhaust filter element 250, which is configured to sealably receive the flow tube 240. In particular, the flow tube 240 is sealably coupled to the exhaust filter element 250 about the exhaust filter inlet 255. Second exhaust filter end cap 256 forms a fluid barrier across upstream volume 251 to define exhaust passage 202 through exhaust media assembly 252 .

[0084] The exhaust filter element 250 is coupled to the second end cap 230 and extends longitudinally outward from the filter element 100. In the current example, the first exhaust filter end cap 254 is an integral, cohesive structure with the second end cap 230. Thus, the exhaust filter element 250 is coupled to the second end cap 230. In some other embodiments, the first exhaust filter end cap 254 can be a separate component from the second end cap 230.

[0085] As an example, similar to the filter media 211 of the filter media assembly 210, the discharge media assembly 252 can be a pleated filter media or a wrapped filter media. However, in some other configurations, the discharge media assembly can be arranged as a media pack for straight-through flow rather than radial flow. The discharge media assembly 252 can be various types of filter media and can combine multiple layers of filter media. In some embodiments, the discharge media assembly 252 is configured to have a lower pressure drop across the discharge media assembly 252 than the filter media 211 that defines the filter passage 204. In some embodiments, the discharge media assembly 252 is configured to have a lower particle filtration efficiency than the filter media 211 that defines the filter passage 204. In some embodiments, the discharge media assembly 252 is configured to have a higher permeability than the filter media 211 that defines the filter passage 204.

[0086] Figure 4 1 is a cross-sectional view of an example filter assembly 101 consistent with the technology disclosed herein. The filter assembly 101 is generally configured to be installed in a fluid filtration system, which will be described below with respect to Figure 8 and Fig. 9 The filter assembly 101 has a primary filter element 100 and a secondary filter element 300. Here, the secondary filter element 300 surrounds the primary filter element 100. The primary filter element 100 and the secondary filter element 300 are connected to each other. Figure 1 to Figure 2 The depiction of the filter element is consistent with the corresponding description.

[0087] The secondary filter element 300 has a secondary media assembly 310 having a third end 312 and a fourth end 314. The third end 312 is positioned toward the first end 112 of the filter media assembly 110 (hereinafter referred to as the "primary media assembly") of the primary filter element 100, and the fourth end 314 is positioned toward the second end 114 of the primary media assembly 110. The secondary media assembly 310 defines a cavity 316 extending from the third end 312 to the fourth end 314. The cavity 316 receives the primary filter element 100. An element gap 318 may be defined between an outer circumferential limit 111a of the filter media assembly 110 and an inner circumferential limit 311b defined by the secondary media assembly 310. The element gap 318 may extend in a radial direction between the outer circumferential limit 111a of the filter media assembly 110 and the inner circumferential limit 311b defined by the secondary media assembly 310.

[0088] In some embodiments, the secondary media assembly 310 can be configured to facilitate degassing of liquid being filtered by the primary filter element 100. In some embodiments, the secondary media assembly 310 is configured to filter a bypass fluid. In various embodiments, the secondary media assembly 310 has a higher permeability than the primary media assembly 110. In various embodiments, the primary media assembly 110 has a higher particle filtration efficiency than the secondary media assembly 310. In some embodiments, the secondary media assembly 310 can have a particle filtration efficiency sufficient to meet the minimum filtration requirements of the bypass fluid.

[0089] The secondary media assembly 310 can be constructed from a variety of different types of filter media and combinations of filter media. In some embodiments, the secondary media assembly 310 is constructed from a woven material. In some embodiments, the secondary media assembly 310 is constructed from a non-woven material. The secondary media assembly 310 can have a structural support layer 311 that defines an outer radial boundary of the secondary media assembly 310. The structural support layer 311 is configured to prevent the other layers of the secondary media assembly 310 from bursting. Figure 1 to Figure 2 ) The description of structural support member 113 of primary media assembly 110 also applies to structural support layer 311. In some embodiments, structural support layer 311 may be omitted, and in other embodiments, multiple structural support layers may be combined in filter assembly 101. In some embodiments, structural support layer 311 may also help facilitate degassing of the filtered fluid.

[0090] In an embodiment, the secondary media component 310 is made of a woven metal mesh, such as a stainless steel mesh. In some embodiments, the secondary media component 310 has a pleated wire mesh. The pleated wire mesh can be stainless steel. In some embodiments, the secondary media component 310 has multiple layers of wire mesh. For example, the secondary media component 310 can be constructed with a first layer of wire mesh adjacent to a second layer of wire mesh. In some examples, the secondary media component 310 is constructed of a first layer of stainless steel wire mesh adjacent to a second layer of pleated carbon steel mesh. In embodiments where the secondary media component 310 is a multiple layer of wire mesh, the wire mesh layers can be pleated together. In some embodiments, the fibers (e.g., metal fibers) are coated. A polymer or non-polymer coating, such as a resin, can be used. The secondary media component 310 can be arranged in a tubular shape.

[0091] The third end cap 320 is coupled to the third end 312 of the secondary media assembly 310 and is configured to be coupled to the filtration system. The third end cap 320 has a radial edge 321 on one longitudinal end and a third potting structure 322 on an opposite longitudinal end. The third potting structure 322 forms a receiving channel configured to receive the third end 312 of the secondary media assembly 310. The radial potting structure 322 has an inner circumferential flange 322a, an outer circumferential flange 322b, and an annular surface 322c adjoining the inner circumferential flange 322a and the outer circumferential flange 322b. The inner circumferential flange 322a and the outer circumferential flange 322b extend in the longitudinal direction around the longitudinal axis x.

[0092] The third end cap 320 defines a third end cap opening 324 (wherein "third end cap" is used herein to modify "opening" because the opening is defined by the third end cap) configured to receive the primary filter element 100. The third end cap 320 has an inner circumferential sealing surface 327 that is configured to form a fluid seal with the outer circumferential sealing surface 128 of the first end cap 120. The inner circumferential sealing surface 327 radially protrudes into the cavity 316. The third end cap 320 also defines an outer circumferential sealing surface 329 that is configured to form a seal with a system component, which is Figure 8 The outer circumferential sealing surface 329 of the third end cap 320 is similar to that described above with respect to the outer circumferential sealing surface 128 of the first end cap 120 .

[0093] The fourth end cap 330 is coupled to the fourth end 314 of the secondary media assembly 310. The fourth end cap 330 has a media potting structure 336 configured to receive the fourth end 314 of the secondary media assembly 310. The fourth end cap 330 forms a fluid barrier across the cavity 316. In some embodiments, a pressure relief valve may be incorporated into the fourth end cap 330 that is configured to open at a threshold pressure within the secondary filter element 300.

[0094] In the present example, the second end cap opening 136 of the primary filter element 100 places the central opening 146 of the flow tube 140 in direct fluid communication with the flow gap 332 defined between the fourth end cap 330 and the second end cap 130. The flow gap 332 defines a portion of the exhaust passage 102 that extends from the second end cap opening 136 to the secondary media assembly 310. Thus, the secondary media assembly 310 is an exhaust filter, which is different from the above-described Figure 3 (and described below Figure 5 ) in contrast to the configuration with a separate exhaust filter. A spacer 334 may be disposed between the fourth end cap 330 and the second end cap 130 to maintain the flow gap 332. The spacer 334 may extend between the fourth end cap 330 and the second end cap 130 in the longitudinal direction.

[0095] As discussed above, the filter passage 104 extends from the first passage opening 122 through the central passage 116 through the filter media assembly 110. However, in the present example, the filter passage 104 additionally extends radially outward from the filter media assembly 110 through the element gap 318 and the secondary media assembly 310. Thus, while the drain passage 102 and the filter passage 104 are separate in the primary filter element 100, the filter passage 104 merges with the drain passage 102 outside of the primary filter element 100.

[0096] Figure 5 is an alternative configuration of a filter assembly 201 consistent with various embodiments. The filter assembly 201 incorporates a primary filter element 200 that is similar to the primary filter element described above with reference to Figure 3 The filter element 200 discussed above is consistent with the exhaust filter element 250. The filter assembly 201 also incorporates a secondary filter element 400, which is similar to the filter element described above with reference to FIG. Figure 4 The secondary filter element 300 discussed is generally identical (except where such features and functions are inconsistent with the present description).

[0097] The primary filter element 200 is disposed in the secondary media assembly 410 of the secondary filter element 400. In the current example, the exhaust filter element 250 of the primary filter element 200 is coupled to the second end cap 230 and the fourth end cap 430. Instead of extending across the cavity 416, in this example, the fourth end cap 430 defines a central opening 438 that receives the exhaust filter element 250. The fourth end cap 430 has an inner circumferential sealing surface 439 that forms a seal with the outer circumferential sealing surface 253 of the first exhaust filter end cap 254. Here, as described above with reference to Figure 3As discussed, first exhaust filter end cap 254 is part of second end cap 230 of primary filter element 200. In some alternative embodiments where the first exhaust filter end cap is a separate component from the second end cap, the inner circumferential sealing surface of the fourth end cap can form a seal with a mating surface of the second end cap. Figure 3 Here, the exhaust passage 202 extends through the flow tube 240 and the exhaust filter element 250. It should be noted that the exhaust passage 202 also extends through the fourth end cap 430.

[0098] Fig. 6A is a schematic diagram of an example system 10 consistent with the technology disclosed herein. In various embodiments, the system 10 can be consistent with a hydraulic system. The system 10 can be consistent with the tank assembly described herein. The system 10 has a filter assembly 12 having a primary media assembly 50, a secondary media assembly 60, a filter assembly outlet 80, a filter passage 20, a bypass passage 70, a drain passage 30, and a fill port passage 40.

[0099] The primary media assembly 50 and the secondary media assembly 60 are generally consistent with the primary filter media assemblies and secondary filter media assemblies disclosed elsewhere herein. As described herein, the primary media assembly 50 can be a component of a primary filter element, and the secondary media assembly 60 can be a component of a secondary filter element. The secondary media assembly 60 is configured to be in fluid communication with the primary media assembly 50. The secondary media assembly 60 is also in fluid communication with the filter assembly outlet 80. In various embodiments, the secondary media assembly 60 is in direct fluid communication with the filter assembly outlet 80, such as where the filter assembly outlet 80 is defined on the downstream side of the secondary media assembly 60. In various embodiments, the filter assembly outlet 80 leads to a fluid tank 90, such as a hydraulic fluid tank.

[0100] The filter passage 20 extends through the primary media assembly 50, the secondary media assembly 60, and the filter assembly 80. The filter passage 20 can be configured to receive hydraulic fluid from the implement 22 in the system 10 and return the hydraulic fluid to the fluid tank 90. ​​The secondary media assembly 60 is positioned downstream of the primary media assembly 50 along the filter passage 20. The filter passage 20 can be used in conjunction with the filter assembly 80 described below. Figures 7 to 10 The discussion is consistent.

[0101] In various embodiments, a bypass passage 70 extends from the filter passage 20 through the secondary media assembly 60 and the filter assembly 80. The bypass passage 70 bypasses the primary media assembly 50, which means that the bypass passage 70 does not extend through the primary media assembly 50. The bypass passage 70 can have a bypass valve 72 in fluid communication with the filter passage 20. The bypass valve 72 can normally block the bypass passage 70, and when the fluid pressure in the filter passage 20 exceeds a minimum value, the bypass valve 72 can open so that the fluid flow bypasses the primary media assembly 50. In various embodiments, the bypass passage 70 overlaps or merges with the drain passage 30. In some embodiments, the bypass passage 70 overlaps or merges with the fill port passage 40. The bypass valve 72 can be used with reference to the following Fig. 9 Consistent with bypass valves described elsewhere in this application. In some embodiments, bypass valve 72 and bypass passage 70 may be omitted from system 10. Although a single bypass valve 72 is depicted and discussed in this disclosure, it will be appreciated that multiple bypass valves may be incorporated into the system.

[0102] The drain passage 30 extends through the secondary media assembly 60 and the filter assembly outlet 80. The drain passage 30 avoids the primary media assembly 50, which means that even though the drain passage 30 can physically pass through a primary filter element having a primary media assembly 50 (such as, for example, reference Figure 4 and Figure 5 30 is not filtered by the primary media assembly 50. In various embodiments, the exhaust passage 30 is configured to receive fluid leakage from the motor, pump, valve or other component housing 32 of the hydraulic system. In various embodiments, the exhaust pipe is a housing exhaust pipe. The exhaust passage is further described below. In some embodiments, the exhaust passage 30 and the filter passage 20 merge downstream of the primary media assembly 50.

[0103] Fill port passage 40 extends from fill port 42 through secondary media assembly 60 and filter assembly outlet 80. Fill port 42 is generally configured to receive fluid added to system 10 by a user. Fill port passage 40 bypasses / avoids / does not pass through primary media assembly 50. In various embodiments, fill port passage 40 and drain passage 30 overlap. In some embodiments, the fill port passage and drain passage do not overlap. In some embodiments, the fill port and fill port passage are omitted. Example fill ports are described in more detail below.

[0104] The secondary media assembly 60 may be a plurality of filter media assemblies. Figure 5 As discussed, the filtration passage can extend through one secondary media component downstream of the primary filter media, and the exhaust passage can extend through another secondary media component as an exhaust filter element, which can be similar to that described with reference to Figure 5 A secondary media assembly is disclosed.

[0105] Figure 6B is a schematic diagram of an example system 11 consistent with the technology disclosed herein. In various embodiments, the system 11 can be consistent with a hydraulic system. The system 11 can be consistent with the tank assembly described herein. The system 11 has a filter assembly 13 having a primary media assembly 51, a secondary media assembly 63, a filter passage 21, a drain passage 31, a filter passage outlet 81, and a drain passage outlet 83.

[0106] The primary media assembly 51 and the secondary media assembly 63 are generally consistent with the primary filter media assemblies and secondary filter media assemblies disclosed elsewhere herein. As described herein, the primary media assembly 51 can be a component of a primary filter element, and the secondary media assembly 63 can be a component of a secondary filter element. The secondary media assembly 63 is configured to be in fluid communication with the primary media assembly 51. The secondary media assembly 63 is in fluid communication with the filter passage outlet 81. The filter passage outlet 81 is downstream of the secondary media assembly 63. In various embodiments, the secondary media assembly 61 is in direct fluid communication with the filter passage outlet 81, such as where the filter passage outlet 81 is defined on the downstream side of the secondary media assembly 61. In various embodiments, the filter passage outlet 81 leads to a fluid tank 91, such as a hydraulic fluid tank.

[0107] The filter passage 21 extends through the primary media assembly 51, the secondary media assembly 63, and the filter passage outlet 81. The filter passage 21 can be configured to receive hydraulic fluid from the implement 23 in the system 11 and return the hydraulic fluid to the fluid tank 91. The secondary media assembly 63 is positioned downstream of the primary media assembly 51 along the filter passage 21. The filter passage 21 can be consistent with the discussion herein.

[0108] The discharge passage 31 extends to the discharge passage outlet 83. The discharge media assembly 61 is disposed across the discharge passage 31. Fluid flowing through the discharge passage 31 is filtered by the discharge media assembly 61. The discharge passage outlet 83 may be defined by, for example, the downstream side of the discharge media assembly 61. The discharge passage outlet 83 and the filter passage outlet 81 are configured to merge (such as, in the fluid tank 91). The discharge passage 31 avoids the primary media assembly 51, which means that: even though the discharge passage 31 can physically pass through a primary filter element having the primary media assembly 51 (such as, for example, reference Figure 4 and Figure 51 and 2). The discharge passage 31 is also not filtered by the primary media assembly 51. In various embodiments, the discharge passage 31 is configured to receive fluid leakage from the motor, pump, valve or other component housing 33 of the hydraulic system. In various embodiments, the fluid leakage comes from the housing drain pipe. The discharge passage is further described below. In this example, the discharge passage 31 is generally separated from the filter passage 21 upstream of the discharge passage outlet 83.

[0109] The filter assembly 13 generally has at least one fluid flow passage 71 / 41 that selectively extends to the discharge passage 31 upstream of the discharge media assembly 61. The fluid flow passage 71 / 41 is configured to bypass the primary media assembly 51, meaning that the fluid flow passage 71 / 41 does not extend through the primary media assembly 51. In some embodiments, the fluid flow passage 71 / 41 is in selective fluid communication with the filter passage 21.

[0110] In various embodiments, the fluid flow passage is a bypass passage 71 that selectively extends from the filter passage 21 to the discharge passage 31. The bypass passage 71 is configured to selectively bypass the primary media assembly 51, which means that the bypass passage 71 does not extend through the primary media assembly 51. The bypass passage 71 extends from a position upstream of the primary media assembly 51 to a position upstream of the discharge media assembly 61. The bypass passage 71 can have a bypass valve 73 in fluid communication with the filter passage 21. The bypass valve 72 can normally block the bypass passage 71, and when the fluid pressure in the filter passage 21 exceeds a minimum value, the bypass valve 73 opens so that the fluid flow bypasses the primary media assembly 51. In various embodiments, the bypass passage 71 merges with the discharge passage 31. The bypass valve 73 can be consistent with the bypass valve described herein.

[0111] In some embodiments, the fluid flow passage is a fill port passage 43 extending from the fill port 41 through the discharge media assembly 61 and the discharge passage outlet 83. The fill port 41 is generally configured to receive fluid added to the system 11 by the user via the filter assembly 13. The fill port passage 43 can be selectively opened by the user. The fill port passage 43 avoids or does not pass through the primary media assembly 51. In various embodiments, the fill port passage 43 is merged with the discharge passage 31. Example fill ports are described in more detail throughout this specification. In some embodiments (such as, the embodiments depicted here), the bypass passage 71 is merged with the fill port passage 43.

[0112] In some alternative examples, the bypass path can be similar to the reference Fig. 6AIn some embodiments, the bypass passage is configured to bypass the primary media assembly and extend to the secondary media assembly. Similarly, in some alternative configurations, the fill port passage 43 is configured to extend to the secondary media assembly 63 instead of the exhaust media assembly 61. In some alternative embodiments, the fill port and fill port passage are omitted. In some embodiments, the bypass passage is omitted.

[0113] The secondary media assembly 63 can be a variety of types of filter media assemblies as described elsewhere herein. The exhaust media assembly 61 can be similar to the types of filter media assemblies described herein (e.g., with respect to Figure 3 ) is consistent with the discharge media components described.

[0114] Figure 7 is a perspective view of an example system consistent with the techniques disclosed herein. The system has a filter cover assembly 509 and a filter assembly 101 (such as the one described above with reference to FIG. Figure 4 The filter assembly 101 in question). Figure 8 yes Figure 7 An example first cross-sectional view of an example system of FIG. Fig. 9 yes Figure 7 An example second cross-sectional view of an example system. The following description can be used to observe Figures 7 to 9 .

[0115] The system 500 can be consistent with a hydraulic system. In particular, the filter media assembly 110, 310 of the filter assembly 101 can be disposed in a fluid tank. The system 500 has a filter cover assembly 509 having a filter head 510 configured to be coupled to the filter assembly 101. The filter head 510 defines a flange 560 configured to be coupled to the tank around the tank opening. The filter cover assembly 509 also has a filter cover 520 configured to be detachably coupled to the filter head 510. The filter cover 520 is coupled to the filter head 510 via a mating feature 506, which in the current example is a fastener opening 506 defined by the filter head 510 and the filter cover 520. The fastener opening 506 is configured to receive a fastener, such as a screw or bolt. The filter cover 520 and the filter head 510 define a circumferential sealing area 530, which forms a seal between the filter cover 520 and the filter head 510. The circumferential sealing area 530 extends around the central axis x.

[0116] The filter cover assembly 509 is configured to be removably coupled to the primary filter element 100. In the current example, the filter cover assembly 509 is configured to be removably coupled to the filter assembly 101, and thus to the primary filter element 100. The outer circumferential sealing surface 329 forms a seal with a corresponding structure of the filter cover assembly (and more specifically, the filter head 510) around the third end cap 320. In the current example, the corresponding structure of the filter head 510 is the inner radial sealing surface 511. Moreover, the flow tube 140 is configured to be sealably coupled to the filter cover assembly 509. In particular, in this example, the filter cover 520 has a first tube connector 514, which is configured to be sealably coupled to the first tube end 142 of the flow tube 140 around the first tube opening 141.

[0117] Although Figures 8 to 9 One example configuration is depicted, but other configurations are contemplated for coupling filter cover assembly 509 to filter assembly 101. For example, in embodiments where first tube end (142) is positioned between first end cap (120) and second end cap (130), first tube connector (514) may be configured to extend into a central opening of filter media assembly (110).

[0118] The filter cover assembly 509 defines a filter passage 516 and a drain passage 524 separate from the filter passage 516 (at Figure 8 510 ). More specifically, the filter cap 520 and the filter head 510 cumulatively define a filter passage 516 and a drain passage 524 separate from the filter passage 516. In various embodiments, the filter passage 516 is configured to receive hydraulic fluid from an implement in the hydraulic system that flows back to the fluid tank. In various embodiments, the drain passage 524 is configured to receive fluid leakage from a motor, pump, valve, or other component of the hydraulic system.

[0119] One or more conduits 512, 522 extend from the filter passage 516, and a drain passage 524 is separate from the filter passage 516. In particular, the filter cap assembly 509 defines a drain conduit 522 (specifically defined by the filter cap 520) and a fluid return conduit 512 (specifically defined by the filter head 510). The drain passage 524 extends from the drain conduit 522 to the first tube opening 141 defined on the first tube end 142 of the flow tube 140. The drain passage 524 defines the drain passage 524 described above with reference to Figure 2 and Figure 4The portion of the exhaust passage 102 discussed. Thus, the exhaust passage 102 extends from the exhaust conduit 522, through the filter cap assembly 509, through the first tube connector 514 and the first tube opening 141, along the flow tube 140, out of the second end cap opening 136, radially outward from the second end cap opening 136 through the flow gap 332 between the second end cap 130 and the fourth end cap 330, and radially outward through the secondary media assembly 310. Thus, in an example consistent with the present example, the secondary filter element 300 is an exhaust filter element.

[0120] It should be noted that the flow tube 140 allows the exhaust passage 524 to avoid flowing through the primary media assembly 110. The flow tube 140 fluidly connects the exhaust passage 524 and the exhaust filter element 300, which is the secondary filter element 300. The specific configuration of the exhaust passage 102 can have various advantages. For example, routing the flow tube 140 (and therefore, the exhaust passage 102) outside the filter assembly 101 can prevent air in the flow tube 140 from accumulating in the filter assembly 101. Routing the flow tube (and therefore, the exhaust passage 102) outside the filter assembly 101 can also reduce the fluid pressure at both ends of the exhaust passage 102, which reduces the fluid pressure on the motor housing (or other component housing upstream of the exhaust passage 102). Furthermore, routing the flow tube 140 to the bottom of the primary filter element 100 and the secondary filter element 300 limits further aeration of the fluid in the fluid tank compared to fluid introduced to the fluid tank toward the top of the filter element 100, 300, where gravity would increase the impact between the discharged fluid and any fluid in the fluid tank. The fluid seal 128, 327 between the primary filter element 100 and the secondary filter element 300 prevents air in the element gap 318 between the filter elements 100, 300 from entering the filter cap assembly 509, so that eventually, the air will pass through the secondary media assembly 310 into the fluid tank.

[0121] The filter passage 516 extends from the fluid return inlet 513 defined by the fluid return conduit 512 to the first end cap 120, and specifically to the first channel opening 122 defined by the first end cap 120 and the primary media assembly 110. The filter passage 516 forms the Figure 2 and Figure 4 104. Thus, filter passage 104 extends from fluid return conduit 512, through filter cap assembly 509 (more specifically, filter head 510), first passage opening 122, through central passage 116 (outside flow tube 140), and radially outward through primary media assembly 110 and secondary media assembly 310.

[0122] In the current example system 500, the filter cap assembly 509 defines a fill port 527 that is in selective fluid communication with the discharge passage 524. A removable cap 526 is removably disposed across the fill port 527. The removable cap 526 can be selectively removed by a user in order to add a fluid (such as a hydraulic fluid) to the system 500. The advantage of configuring the fill port 527 to be in fluid communication with the discharge passage 524 is that the new fluid added to the system is filtered by the discharge filter (here it is a secondary filter). In the current example, the removable cap 526 and the filter cap assembly 509 are engaged with each other by mating threads 528. The removable cap 526 can be decoupled from the filter cap assembly 509 by manually rotating the removable cap 526 relative to the filter cap assembly 509, which manually rotates to disengage the mating threads 528.

[0123] Although in the current example the filter cap assembly 509 has a filter cap 520 coupled to a filter head 510, in some embodiments, the filter cap assembly has a filter cap without a filter head. In such embodiments, the filter cap can be mounted directly into the fluid tank. The filter cap assembly is typically configured to interface with the filter cartridge and direct the discharge flow and the filtered flow to the associated flow passages defined by the filter element.

[0124] In various embodiments (including Fig. 9 In the example depicted in ), the filter system has a bypass valve 550 disposed between the discharge passage 524 and the filter passage 516. In particular, the filter cap assembly 509 has a bypass valve 550. In the event that the fluid pressure in the filter passage 516 exceeds a threshold value, the bypass valve 550 selectively directs the fluid flow from the filter passage 516 to the discharge passage 524. Thus, the bypass fluid flow enters the discharge passage 102 and is filtered by the secondary media assembly 310. This can be an advantage compared to a system without a filter for bypassing the fluid flow. In some embodiments, the bypass valve 550 can be omitted.

[0125] Although the examples currently depicted and currently discussed have a primary filter element 100 and a secondary filter element 300, the secondary filter element 300 may be omitted in various embodiments of the current technology. Figure 3 described), the secondary filter element may be omitted.

[0126] Fig.10 is a simplified schematic cross-sectional view of yet another example system 600 consistent with the techniques disclosed herein. Figure 3 Filter elements (such as those described above) are coupled to a filter cover assembly 609. The filter cover assembly 609 is similar to the filter cover assembly described above with reference to Figures 7 to 9Filter cover assembly 509 is described.

[0127] Different from Figures 7 and 8 , where the exhaust filter element 250 is a separate component from the secondary filter element 400. The exhaust filter element 250 is coupled to the filter cap assembly 609 via the exhaust filter element 250 being coupled to the filter assembly 201 (particularly, the primary filter element 200 and the secondary filter element 400), which is coupled to the filter cap assembly 609. Although the flow tube 240 extends into the filter cap assembly 609 in the current example, in some other embodiments, the filter cap assembly may have a flow tube connector that extends into the primary media assembly to couple to the flow tube.

[0128] Fig.11 701 is a cross-sectional view of another example filter assembly 701 consistent with the technology disclosed herein. The filter assembly 701 is generally configured to be installed in a fluid filtration system, which will be described in more detail below. The filter assembly 701 has a primary filter element 700 and a secondary filter element 800. Here, the secondary filter element 800 surrounds the primary filter element 700. The example filter assembly 701 has a central axis x extending in the longitudinal direction.

[0129] The primary filter element 700 has a primary media assembly 710 defining a central channel 716, a first end cap 720 coupled to a first media end 712 of the primary media assembly 710, and a second end cap 730 coupled to a second media end 714 of the primary media assembly 710. The primary media assembly 710 is generally configured to filter a fluid and may be consistent with the description of the other filter media assemblies described above, and thus has a filter media 711 and optional structural support.

[0130] The first end cap 720 is generally configured to retain the first media end 712 of the primary media assembly 710, such as via a media potting structure that may be consistent with the description above. The first end cap 720 defines a portion of the filter passage 704 through the primary media assembly 710. In particular, the first end cap 720 defines a first end cap opening 721 that extends in a longitudinal direction from the exterior of the filter assembly 701 to the central passage 716.

[0131] The first end cap 720 has a circumferential sealing surface 728 around the longitudinal axis x, which is configured to form a seal with the filter system components, which will be described in more detail below. The circumferential sealing surface 728 shares the central axis x of the primary media assembly 710 and the central channel 716. The circumferential sealing surface 728 can be a circumferential cavity configured to receive an elastomeric component (such as, an o-ring 727). In some embodiments, the circumferential cavity is discontinuous, while in other embodiments, the circumferential cavity is continuous. In the current embodiment, the circumferential sealing surface 728 is around the first end cap opening 721. In particular, the first end cap 720 defines a tubular extension 724 extending longitudinally outward from the first end cap 720 around the first end cap opening 721. The circumferential sealing surface 728 is defined around the outer radial surface of the tubular extension 724, but in some embodiments, the circumferential sealing surface can be defined around the inner radial surface of the tubular extension.

[0132] The second end cap 730 is generally configured to retain the second media end 714 of the primary media assembly 710 and may have a second media potting structure 734 as described herein. The second end cap 730 defines a portion of the filter passage 704 through the primary media assembly 710. In particular, the second end cap 730 blocks the central passage 716.

[0133] In the current example, the filter element lacks a flow tube that defines a portion of the exhaust passage, as described above with reference to other figures. Unlike some other embodiments herein, in this example, the entire central channel 716 defines a portion of the filter passage 704. Similarly, the entire first end cap opening 721 defines a portion of the filter passage 704. In the current example, the exhaust passage 702 is defined outside the primary filter element 700, so that the exhaust passage 702 is separated from the filter passage 704 within the primary media assembly 710, which will be described in more detail below.

[0134] The secondary filter element 800 has a secondary media assembly 810 having a third end 812 and a fourth end 814. The third end 812 is positioned toward the first end 712 of the primary media assembly 710, and the fourth end 814 is positioned toward the second end 714 of the primary media assembly 710. The secondary media assembly 810 defines a cavity 816 extending from the third end 812 to the fourth end 814. The cavity 816 receives the primary filter element 700. An element gap 818 can be defined between an outer circumferential limit 711a of the primary media assembly 710 and an inner circumferential limit 811b defined by the secondary media assembly 810. The element gap 818 can be in a radial direction between the outer circumferential limit 711a of the primary media assembly 710 and the inner circumferential limit 811b defined by the secondary media assembly 810. The secondary media assembly 810 is generally configured consistent with the description of the other secondary filter media assemblies discussed above.

[0135] The third end cap 820 is coupled to the third end 812 of the secondary media assembly 810 and is configured to be coupled to the filtration system. The third end cap 820 has a third potting structure 822 on one longitudinal end of the third end cap 820. The third potting structure 822 can be consistent with other potting structures described herein. The third end cap 820 has a plurality of inwardly directed radial ribs 821 extending from the third potting structure 822 to the outer surface 726 of the first end cap 720. The radial ribs 821 are on the opposite longitudinal ends of the third end cap 820 relative to the third potting structure 822. The third end cap 820 does not have the radial edges discussed in the previous examples.

[0136] The third end cap 820 defines a third end cap opening 824 configured to receive the primary filter element 700. In this embodiment, the third end cap 820 does not form a fluid seal with the outer circumferential sealing surface of the first end cap 720. Instead, the third end cap 820 and the primary filter element 700 define an end cap gap 722 therebetween. The end cap gap 722 can extend between the third end cap 820 and the primary filter element 700 in a radial direction. The fluid flow passage 706 extends from the end cap gap 722 into the element gap 818 between the primary media assembly 710 and the secondary media assembly 810, and passes out of the secondary media assembly 810. Thus, the end cap gap 722 can define a portion of the fluid flow passage 706, such as a fluid flow passage 706 inlet 722 to the filter assembly 701. In this example, the fluid flow passage 706 merges with the discharge passage 702 in the element gap 818. In some alternative embodiments, both the fluid flow passage and the exhaust passage may extend through one of the third and fourth end caps to the secondary media assembly 810 .

[0137] In the current example, the end cap gap 722 can be a plurality of discrete openings defined between the third end cap 820 and the first end cap 720, wherein the plurality of ribs separate each of the discrete openings that cumulatively define the end cap gap 722. The plurality of discrete openings are defined around the central axis x. The end cap gap 722 extends circumferentially around the first end cap opening 721. Thus, the outer diameter of the inlet 722 is greater than the outer diameter of the first end cap opening 721.

[0138] The third end cap 820 also defines an outer peripheral sealing surface 829 that is configured to form a seal with a system component. Fig.12 The outer circumferential sealing surface 829 of the third end cap 820 is similar to the corresponding features of the other components described above.

[0139] The fourth end cap 830 is coupled to the fourth end 814 of the secondary media assembly 810. Consistent with the previously described embodiments, the fourth end cap 830 has a media potting structure 836 configured to receive the fourth end 814 of the secondary media assembly 810. In the current example, the fourth end cap 830 does not form a fluid barrier across the cavity 816. Instead, the discharge passage 702 extends through the fourth end cap 830. In particular, the fourth end cap 830 defines a fourth end cap opening 838 as a discharge passage inlet of the filter assembly 701. The discharge passage 702 extends from the fourth end cap opening 838, through the cavity 816, and out through the secondary media assembly 810. Thus, the secondary media assembly 810 functions as a discharge filter. A spacer 834 may be disposed between the fourth end cap 830 and the second end cap 730 to maintain a flow gap 832 therebetween. The spacer 834 may extend between the fourth end cap 830 and the second end cap 730 in a longitudinal direction.

[0140] In the current example, the filter assembly 701 defines a filter passage 704, a discharge passage 702, and a fluid flow passage 706. The filter passage 704 extends through the primary media assembly 710, and the discharge passage 702 bypasses or avoids (does not extend through) the primary media assembly 710. More generally, the discharge passage 702 does not extend through the primary filter element 700. Similarly, the fluid flow passage 706 avoids the primary filter element 700 including the primary media assembly 710. The fluid flow passage 706 can be consistent with the bypass passage, the fill port passage, or both the bypass passage and the fill port passage, as will be discussed in more detail below. It should be noted that the filter passage 704 merges with the discharge passage 702 and the fluid flow passage 706 downstream of the primary media assembly 710.

[0141] Fig.12 is a perspective view of an example tank assembly 900 consistent with the techniques disclosed herein, and Fig.13 is an exploded view of an example tank assembly 900 . Fig.14 is a first cross-sectional view of the example assembly 900, and Fig.15 900. The assembly has a canister 960, a filter cap assembly 909, and a filter assembly 701 ( Figure 13 to Figure 14 )(such as, reference above Fig.11 The filter assembly 701 discussed herein can be viewed together with the following description. Figures 12 to 15 .

[0142] The fluid tank 960 generally defines a fluid cavity 961 configured to receive a fluid and a filter assembly opening 918 ( Fig.13). In the current embodiment, the fluid tank 960 has a filter support platform 964 configured to support a portion of the filter assembly 701. Specifically, the filter support platform 964 is configured to support the bottom portion of the filter assembly 701. The fluid tank 960 also has a fluid outlet 966 configured to be in fluid communication with other system components (such as a fluid pump). The fluid tank 960 also defines a drain tank inlet 968.

[0143] The filter assembly 701 is generally disposed within the fluid cavity 961 and around the filter assembly opening 918 ( Fig.13 ) is connected to the tank 960. In the current example, unlike some previously described examples, the filter cover assembly 909 does not have a separate filter head. On the contrary, in the current example, the filter head structure 910 is defined by the tank 960 itself. The system 900 has a filter cover assembly 909, which has a filter head structure 910 configured to be connected to the filter assembly 701. The filter cover assembly 909 also has a filter cover 920 configured to be detachably connected to the filter head structure 910. The filter cover 920 is connected to the filter head structure 910 via a matching feature 906, which in the current example is a matching thread 906 defined by the filter head structure 910 and the filter cover 920 around the central axis x. The filter cover assembly 909 and the filter support platform 964 can apply a compressive force on the filter assembly 701 to fix the filter assembly 701 in an appropriate position.

[0144] The filter cover 920 and the filter head structure 910 are configured to surround the filter assembly opening 918 ( Fig.13 ) forms at least one seal. Fig.14 and Fig.15 As can be seen in the filter cover 920 and the filter head structure 910, a first circumferential sealing area 930 and a second circumferential sealing area 932 are defined. Each of the first circumferential sealing area 930 and the second circumferential sealing area 932 is configured to be arranged around the central axis x. The first circumferential sealing area 930 is positioned toward the distal longitudinal end of the mating thread 906 and / or the distal longitudinal end of the filter cover 920. The second circumferential sealing area 932 is positioned toward the opposite longitudinal end of the filter cover 920.

[0145] Filter cover assembly 909 is configured to be removably coupled to canister 960. In the current example, filter cover assembly 909 is configured to be removably coupled to filter assembly 701, and therefore to primary filter element 700. Outer circumferential sealing surface 829 forms a seal around third end cap 820 with corresponding structure of filter cover assembly 909 (and more specifically, filter head structure 910 of canister 960). In the current example, the corresponding structure of filter head structure 910 is inner radial sealing surface 911. In some alternative embodiments, the third end cap may define an inner circumferential sealing surface, and the corresponding structure of the filter head structure may be an outer circumferential sealing surface.

[0146] Moreover, the first end cap 720 is configured to sealably couple to the filter cap assembly 909 about the first end cap opening 721. In particular, in this example, the filter cap 920 has a first tube connector 914 that is configured to sealably couple to the circumferential sealing surface 728 of the tubular extension 724 about the first end cap opening 721, which is the first inlet of the filter assembly 701. Other configurations are also contemplated for coupling the filter cap assembly 909 to the filter assembly 701.

[0147] Tank assembly 900 is limited to Figure 14 to Figure 15 Filter passage 704 is visible in FIG. Filter assembly 701 ( Fig.11 ) is a portion of the filter passage 704. The filter cap 920 and the filter head structure 910 define a portion of the filter passage 704 between the first circumferential seal area 930 and the second circumferential seal area 932. The filter cap assembly 909 defines a filter conduit 912 that defines a fluid return inlet 913 to the filter passage 704 of the tank assembly 900. In this particular embodiment, the filter head structure 910 defines the fluid return conduit 912, but in some other embodiments, the filter cap 920 can define the fluid return conduit 912. In various embodiments, the filter passage 704 is configured to receive hydraulic fluid from an implement in the hydraulic system that is returned to the fluid tank 960.

[0148] The canister assembly 900 is configured to selectively define a bypass passage 952 (at the Fig.14 ). Bypass passage 952 selectively extends from filter passage 704 through secondary filter element 800 to the filter assembly outlet, where the filter assembly outlet is the downstream face of secondary filter element 800. In various embodiments (including Figures 13 to 15 In the example depicted in FIG. 1 , the filtration system has a fluid flow passage 706 (disposed between the filtration passage 704 and the filter assembly 701) Fig.11) inlet 722 (which is referred to as the end cap gap 722 above). In particular, the filter cap assembly 909 has a bypass valve 950. In the event that the fluid pressure in the filter passage 704 exceeds a threshold, the bypass valve 950 selectively directs the fluid flow from the filter passage 704 to the bypass passage 952. Thus, the bypass fluid flow enters the bypass passage 952 and is filtered by the secondary media assembly 810. This can be an advantage compared to a system without a filter for bypassing the fluid flow. In some embodiments, the bypass valve 950 can be omitted.

[0149] In the current example tank assembly 900, the filter cap assembly 909 defines a fill port 927 in fluid communication with the fluid flow passage 706. The fill port 927 can be in selective fluid communication with the bypass passage 952. The fill port 927 can be positioned downstream of the bypass valve 950 along the bypass passage 952, and can therefore be isolated from the filter passage 704 upstream of the primary media assembly 710. The fill port 927 is defined by a fill port conduit 924 of the filter cap assembly 909. In normal operation, the fill port 927 is isolated from the filter passage 704 within the filter cap assembly 909. In the current embodiment, the fill port 927 extends through a portion of the filter passage 704 downstream of the primary media assembly 710. An advantage of configuring the fill port 927 to be in fluid communication with the bypass passage 952 downstream of the bypass valve 950 is that new fluid added to the system is filtered by the secondary media assembly 810. In some embodiments, the fill port 927 can be omitted.

[0150] A removable cap 926 is removably disposed on the fill port conduit 924 across the fill port 927. The removable cap 926 can be selectively removed by a user to add a fluid (such as hydraulic fluid) to the tank assembly 900. In the current example, the removable cap 926 and the filter cap assembly 909 are connected by mating threads 928 ( Fig.14 ) are mutually engaged. The removable cover 926 can be decoupled from the filter cover assembly 909 by manually rotating the removable cover 926 relative to the filter cover assembly 909, which manually rotates to disengage the mating threads 928.

[0151] The tank assembly 900 also defines a drain passage 702 that has been Fig.11 The exhaust passage 702 ( Figure 14 to Figure 15) extends through the tank 960 to the fourth end cap opening 838 via one or more discharge conduits 962, 962a, 962b. Secondary conduits 962a, 962b may extend from components (such as a motor and / or pump) and merge into a primary discharge conduit 962 extending to the filter assembly 701. The primary discharge conduit 962 extends longitudinally outward from the filter support platform 964 and into the fourth end cap opening 838, which is the third inlet of the filter assembly 701.

[0152] The drain passage 702 is generally isolated from the filter passage 704 upstream of the primary media assembly 710, meaning that the drain passage 702 and the filter passage 704 are distinct and fluidly separate flow paths. The drain passage 702 is isolated from the filter passage 704 in the filter cap assembly 909. In particular, in this example, the filter cap assembly 909 does not define a portion of the drain passage 702. The drain passage 702 extends from the drain canister inlet (multiple) 968 through the drain conduit 962 to the fourth end cap opening 838 defined by the fourth end cap 830 of the filter assembly 701, radially outward from the fourth end cap opening 838 through the flow gap 832 between the second end cap 730 and the fourth end cap 830, and radially outward through the secondary media assembly 810. Thus, in an example consistent with the present example, the secondary filter element 800 is a drain filter element.

[0153] The discharge passage 702 bypasses the primary media assembly 710. The discharge conduit 962 fluidly couples the discharge passage 702 to the discharge filter element 800, which is a secondary filter element 800. The discharge conduit 962 extends from the discharge tank inlet 968 through the fluid cavity 961 of the tank 960 to the filter assembly 701. In the current example, the filter passage 704 entrance to the filter assembly 701 (which is the first end cap opening 721) is on the longitudinal end of the filter assembly 701 opposite the discharge passage 702 entrance to the filter assembly 701 (which is the opening of the fourth end cap 830). Similarly, the fluid return inlet 913 is located toward the first end of the tank 960, and the discharge tank inlet 968 is located toward the second, opposite end of the tank 960.

[0154] The specific configuration of the exhaust passage 702 can have various advantages. For example, routing the exhaust conduit 962 (and therefore, the exhaust passage 702) to avoid the filter assembly 701 can reduce the fluid pressure at both ends of the exhaust passage 702, which reduces the fluid pressure on the motor housing (or other component housing upstream of the exhaust passage 702). In addition, routing the exhaust conduit 962 to the bottom of the filter assembly 701 limits further aeration of the fluid in the fluid tank 960 compared to the fluid toward the top of the filter assembly 701, where gravity will increase the impact between the exhaust fluid and any fluid in the fluid tank 960.

[0155] In some alternative embodiments, the drain passage may extend into the filter cap assembly rather than through the bottom end cap of the filter assembly. In such embodiments, the drain passage may overlap with one or both of the fill port passage and the bypass passage in the filter cap assembly. In such examples, the drain passage would similarly bypass the primary media assembly and extend through the secondary media assembly. In such embodiments, the fluid flow passage 706 (see Fig.11 ) will define a portion of the discharge path.

[0156] The filter passage 704 extends from the fluid return conduit 912 to the first end cap 720, and specifically to a first inlet which is a first end cap opening 721 of the first end cap 720. The filter passage 704 extends from the fluid return conduit 912, through the filter cap assembly 909 and the first end cap 720, through the central passage 716, and radially outward through the primary media assembly 710 and the secondary media assembly 810.

[0157] Although in the current example the filter cover assembly 909 has a filter cover 920 coupled to the filter head structure 910, in some embodiments, the filter cover assembly has a filter cover without a filter head structure. In such embodiments, the filter cover can be directly mounted in the fluid tank. Moreover, in some embodiments, the filter head structure 910 can be a filter head as a component separated from the tank 960. The filter cover assembly is generally configured to dock with the filter element and guide the discharge flow and the filtered flow to the associated flow path defined by the filter element.

[0158] Although the example currently depicted and currently discussed has a primary filter element 700 and a secondary filter element 800, the secondary filter element 800 may be omitted in various embodiments of the current technology. Figure 8 described), the secondary filter element may be omitted.

[0159] Fig.16is a cross-sectional view of another example filter element 1000 consistent with the techniques disclosed herein. Fig.17 1 is a perspective view of an example filter element 1000. The filter element 1000 has a filter media assembly 1010 defining a central channel 1016, a first end cap 1020 coupled to a first media end 1012 of the filter media assembly 1010, a second end cap 1030 coupled to a second media end 1014 of the filter media assembly 1010, and a flow tube 1040 disposed in the central channel 1016.

[0160] The filter element 1000 defines a filter passage 1004 and a drain passage 1002, wherein the filter passage 1004 extends through the filter media assembly 1010 and the drain passage 1002 bypasses / avoids (does not extend through) the filter media assembly 1010. The drain passage 1002 is separate from the filter passage 1004 within the filter element 1000. The drain passage 1002 is generally configured to separate from the filter passage 1004 upstream of the primary media assembly 1010. The filter passage 1004 is configured to merge with the drain passage 1002 downstream of the primary media assembly 1010. Various features and functions of the current example filter element 1000 are generally consistent with the filter elements discussed above (except where such features and functions are inconsistent with the current description or drawings).

[0161] The filter media assembly 1010 is generally configured to filter a fluid. In some embodiments, the filter media assembly 1010 is configured to filter a hydraulic fluid. The first end 1012 of the filter media assembly 1010 is coupled to a first end cap 1020. The second end 1014 of the filter media assembly 1010 is coupled to a second end cap 1030. The filter media assembly 1010 generally has a cylindrical arrangement. The filter media assembly 1010 defines a central channel 1016 extending from the first media end 1012 to the second media end 1014. The central channel 1016 defines a filter passage 1004 and a discharge passage 1002. In the current example, the discharge passage 1002 is an elongated cylinder. The filter passage 1004 forms a tubular structure surrounding the discharge passage 1002.

[0162] The filter media assembly 1010 and the central channel 1016 share a central axis x, wherein the central axis x extends in the longitudinal direction. The filter media assembly 1010 may have a length in the longitudinal direction as previously discussed. The filter media assembly 1010 has a filter media 1011. The filter media 1011 may have a construction consistent with other examples discussed herein, such as being pleated. A structural support 1013 surrounds the filter media 1011. The structural support 1013 defines an outer radial boundary 1018 of the filter media assembly 1010. The structural support 1013 may have a configuration and function as discussed above. In some embodiments, the structural support may abut the filter media along an inner radial boundary of the filter media 1011 around the central channel 1016.

[0163] The first end cap 1020 is generally configured to retain the first media end 1012 of the filter media assembly 1010 and define a portion of the filter passage 1004 through the filter media assembly 1010. The first end cap 1020 is configured to define a portion of the discharge passage 1002, such that the discharge passage 1002 extends through the first end cap 1020. The discharge passage 1002 is separated from the filter passage 1004 by the first end cap 1020. The first end cap 1020 defines a first end cap opening 1021 that extends in a longitudinal direction from the exterior of the filter assembly 1001 to the central passage 1016. In the current example, the first end cap opening 1021 is a combination of a plurality of openings, namely, a first tube receptacle 1024 and a first passage opening 1022.

[0164] The first passage opening 1022 is cumulatively formed by a series of discrete openings, which are opening segments 1022a, 1022b, 1022c, 1022d. Fig.17 1041. A plurality of brackets 1015 separate each of these discrete openings that cumulatively define a first passage opening 1022. The plurality of discrete opening segments 1022a, 1022b, 1022c, 1022d are defined about a central axis x. The first passage opening 1022 is defined between the flow tube 1040 and the filter media assembly 1010. The first passage opening 1022 extends circumferentially around the first tube opening 1041. In some embodiments, the first passage opening 1022 defines a filter passage entrance to the filter element 1000, which will be described in more detail below.

[0165] As in Fig.16 As best seen in FIG. 1 , the first end cap 1020 has a first media potting structure 1023 configured to receive the first end 1012 of the filter media assembly 1010. The first media potting structure 1023 may be as described above with reference to FIG. Figure 1 to Figure 2 In some embodiments, the first end cap 1020 does not have a medium potting structure.

[0166] The first end cap 1020 has an outer circumferential sealing surface 1028 around the longitudinal axis x, which is configured to form a seal with a filter system component, which will be described in more detail below. The outer circumferential sealing surface 1028 shares the central axis x of the filter media assembly 1010 and the central channel 1016. The outer circumferential sealing surface 1028 can be a circumferential cavity configured to receive an elastomeric component (such as an o-ring). In some embodiments, the circumferential cavity is discontinuous, while in other embodiments, the circumferential cavity is continuous. In some embodiments, the first end cap 1020 can define an inner circumferential sealing surface 1025, which is configured to form a seal with a filter system component.

[0167] The second end cap 1030 is generally configured to retain the second media end 1014 of the filter media assembly 1010 and define a portion of the filter passage 1004 through the filter media assembly 1010. The second end cap 1030 is configured to define a portion of the discharge passage 1002, such that the discharge passage 1002 extends through the second end cap 1030. The discharge passage 1002 is separated from the filter passage 1004 by the second end cap 1030. In particular, the second end cap 1030 defines a second tube receptacle 1036 configured to receive the flow tube 1040. In contrast to some other embodiments, in this example, the second end cap 1030 defines a second channel opening 1031 that fluidly couples the environment outside of the filter element 1000 to the portion of the central passage 1016 surrounding the flow tube 1040. The second channel opening 1031 is defined between the flow tube 1040 and the filter media assembly 1010. Similar to the first end cap 1020 , in this example, the second end cap 130 has a plurality of brackets 1035 extending between the second end cap 1030 and the flow tube 1040 that separate each of the discrete openings that cumulatively define the second channel opening 1031 .

[0168] In the current example, the second end cap 1030 has an inner tubular flange 1038 extending longitudinally into the central channel 1016. The inner tubular flange 1038 surrounds the second channel opening 1031. In some embodiments, the second end cap 1030 does not have an inner tubular flange 1038. The second end cap 1030 has a second media potting structure 1034 configured to receive the second end 1014 of the filter media assembly 1010. The second media potting structure 1034 can be consistent with those media potting structures described elsewhere herein. In some embodiments, the second end cap 1030 can omit the second media potting structure 1034.

[0169] The flow tube 1040 is generally configured to define a portion of the exhaust passage 1002. The flow tube 1040 contains the exhaust passage 1002. The flow tube 1040 is generally configured to define a portion of a bypass passage. The bypass passage can merge with the exhaust passage 1002. The flow tube 1040 can be configured to define a portion of a fill port passage. The fill port passage can merge with the exhaust passage 1002. The flow tube 1040 is generally configured to separate the exhaust passage 1002 and the filter passage 1004 through the filter element 1000. The flow tube 1040 has a first tube end 1042 and a second tube end 1044. The first tube end 1042 defines a first tube opening 1041. The second tube end 1044 defines a second tube opening 1043. The flow tube 1040 defines a central opening 1046 extending from the first tube end 1042 to the second tube end 1044. The first tube end 1042 can have a sealing structure configured to form a seal with a system component.

[0170] The flow tube 1040 and its central opening 1046 extend in the longitudinal direction. In the current example, the central opening 1046 forms an elongated cylinder, but in other examples, the central opening can be tapered or formed in other shapes. In the current example, the flow tube 1040 is positioned in the central channel 1016. Specifically, the flow tube 1040 is centrally positioned to the central channel 1016.

[0171] In an example consistent with the current embodiment, a first tube end 1042 of a flow tube 1040 is coupled to a first tube connector 1029 of a first end cap 1020 about a discharge passage 1002. The first tube connector 1029 defines a first tube receptacle 1024 that receives the first tube end 1042 of the flow tube 1040. In some embodiments, the first end cap 1020 does not have a first tube connector 1029. In some embodiments, the first tube connector is separate from and detached from the first end cap. In some other embodiments, the flow tube is a single, unitary structure that is separate from the first end cap and is not directly coupled to the first end cap. In some further embodiments, the first end cap defines a segment of the flow tube, as discussed above in the previous examples. In yet further embodiments, the first end cap and the flow tube are a single, unitary component.

[0172] The flow tube 1040 is coupled to the second end cap 1030 about the second tube receptacle 1036. In particular, the second end cap 1030 has a second tube connector 1032 that defines the second tube receptacle 1036. The flow tube 1040 and the second tube connector 1032 of the second end cap 1030 engage each other in the second tube receptacle 1036 to form a radial seal about the second tube receptacle 1036. Although the second tube end 1044 of the flow tube 1040 frictionally and sealably receives the second tube connector 1032 of the second end cap 1030 in the current example, in some embodiments, the flow tube 1040 can form an integral, unitary structure with the second end cap 1030, such as where the flow tube 1040 and the second end cap 1030 are formed by a single molding operation. In some embodiments, the flow tube 1040 passes through an opening in the second end cap 1030 and is not directly coupled to the second end cap 1030.

[0173] Flow tube 1040 defines a first tube opening 1041. First passage opening 1022 is configured to be fluidly separated from flow tube 1040. First passage opening 1022 is fluidly separated from first tube opening 1041 by flow tube 1040. First tube opening 1041 is in direct fluid communication with a central opening 1046 of flow tube 1040. First passage opening 1022 is in direct fluid communication with a central passage 1016 of filter media assembly 1010. First passage opening 1022 is radially positioned between flow tube 1040 and filter media assembly 1010.

[0174] The filter element 1000 defines a filter passage 1004 extending from a first channel opening 1022 to a second channel opening 1031 via a central channel 1016. The filter passage 1004 extends through a first end cap 1020 and a second end cap 1030. The filter element 1000 defines a filter passage 1004 extending from a first channel opening 1022 through the filter media assembly 1010. The filter element 1000 defines a filter passage 1004 extending from a second channel opening 1031 through the filter media assembly 1010. The filter element 1000 also defines a discharge passage 1002 from a first tube opening 1041 to a second tube opening 1043.

[0175] The flow tube 1040 generally extends between the first end cap 1020 and the second end cap 1030. In this example, the flow tube 1040 extends through the first end cap 1020 and the second end cap 1030, but other configurations are possible.

[0176] Fig.18 1 is a cross-sectional view of an example filter assembly 1001 consistent with the technology disclosed herein. The filter assembly 1001 is generally configured to be installed in a fluid filtration system, which will be described below with respect to Fig.19 and Fig. 20The filter assembly 1001 has a primary filter element 1000 and a secondary filter element 1100. Here, the secondary filter element 1100 surrounds the primary filter element 1000. The primary filter element 1000 and the secondary filter element 1100 are connected to each other. Fig.16 and Fig.17 The depiction is consistent with the corresponding description.

[0177] The secondary filter element 1100 has a secondary media assembly 1110 having a third end 1112 and a fourth end 1114. The third end 1112 is positioned toward the first end 1012 of the media assembly 1010 (hereinafter referred to as the "primary media assembly") of the primary filter element 1000, and the fourth end 1114 is positioned toward the second end 1014 of the primary media assembly 1010. The secondary media assembly 1110 defines a cavity 1116 extending from the third end 1112 to the fourth end 1114. The cavity 1116 receives the primary filter element 1000. An element gap 1118 can be defined between an outer circumferential limit 1011a of the filter media assembly 1010 and an inner circumferential limit 1111b defined by the secondary media assembly 1110. An element gap 1118 may be defined in a radial direction between an outer circumferential limit 1011a of the filter media assembly 1010 and an inner circumferential limit 1111b defined by the secondary media assembly 1110 .

[0178] In some embodiments, the secondary media assembly 1110 can be configured to facilitate degassing of liquid filtered by the primary filter element 1000. In some embodiments, the secondary media assembly 1110 is configured to filter a bypass fluid. In various embodiments, the secondary media assembly 1110 has a higher permeability than the primary media assembly 1010. In various embodiments, the primary media assembly 1010 has a higher particle filtration efficiency than the secondary media assembly 1110. In some embodiments, the secondary media assembly 1110 can have a particle filtration efficiency sufficient to meet the minimum filtration requirements of the bypass fluid. The secondary media assembly 1110 can be constructed from various different types of filter media and combinations of filter media discussed above with respect to other secondary media assemblies described herein.

[0179] The third end cap 1120 is coupled to the third end 1112 of the secondary media assembly 1110 and is configured to be coupled to a filtration system. The third end cap 1120 has a radial rim 1121 on one longitudinal end and a radial potting structure 1122 on an opposite longitudinal end. The radial potting structure 1122 forms a receiving channel configured to receive the third end 1112 of the secondary media assembly 1110. The radial potting structure 1122 can be configured similarly to the other radial potting structures discussed above.

[0180] The third end cap 1120 defines a third end cap opening 1124 configured to receive the primary filter element 1000 (where the first end cap 1020 defines the first end cap opening 1021). Unlike some previous examples, here, the third end cap 1120 does not form a fluid seal with the first end cap 1020. An end cap gap 1126 is defined between the third end cap 1120 and the primary filter element 1000, which defines a fluid flow path to the element gap 1118 between the first media assembly 1010 and the secondary media assembly 1110. The end cap gap 1126 is located radially outward from the central passage 1016. The third end cap 1120 defines an outer circumferential sealing surface 1129, which is configured to form a seal with a system component, which is Fig.18 and Fig.19 The outer circumferential sealing surface 1129 of the third end cap 1120 is similar to that described above with respect to the outer circumferential sealing surface 1028 of the first end cap 1020 .

[0181] The fourth end cap 1130 is coupled to the fourth end 1114 of the secondary media assembly 1110. The fourth end cap 1130 has a media potting structure 1136 configured to receive the fourth end 1114 of the secondary media assembly 1110. The fourth end cap 1130 and the second end cap 1030 are configured to form a fluid barrier across the element gap 1118 between the first media assembly 1010 and the secondary media assembly 1110.

[0182] Fig.19 is with Fig.18 The system 1200 has a fluid tank 1260 having a filter assembly 1001 installed therein. The fluid tank 1260 generally defines a fluid cavity 1261 configured to receive a fluid and a filter assembly opening 1218 configured to receive the filter assembly 1001. The fluid tank 1260 defines a drain tank inlet 1268. Various features and functions of the current example system 1200 are generally consistent with the systems discussed above (except where such features and functions are inconsistent with the current description or figures).

[0183] The filter assembly 1001 is disposed in the fluid cavity 1261 and is coupled to the canister 1260 about the filter assembly opening 1218. The filter cap assembly 1209 is configured to receive the filter assembly 1001. The filter cap assembly 1209 has a filter head 1210 configured to be coupled to the filter assembly 1001. The removable filter cap 1220 is configured to be detachably coupled to the filter head 1210. The filter cap 1220 is coupled to the filter head 1210 via a mating feature, which in the current example is a first circumferential sealing area 1230 configured to define a frictional engagement between the filter head 1210 and the filter cap assembly 1209. The filter cap 1220 and the filter head 1210 can form a sealed connection about the filter assembly opening 1218.

[0184] The system 1200 has a filter support platform 1264 configured to support a portion of the filter assembly 1001. The filter support platform 1264 is configured to be coupled to the filter assembly 1001. The filter cover assembly 1209 and the filter support platform 1264 can exert a compressive force on the filter assembly 1001 to secure the filter assembly 1001 in place.

[0185] The filter cover 1220 and the filter head 1210 define a first circumferential sealing area 1230. The filter head 1210 and the filter assembly 1001 define a second circumferential sealing area 1232. Each of the first circumferential sealing area 1230 and the second circumferential sealing area 1232 is configured to be arranged around the central axis x. The first circumferential sealing area 1230 is positioned toward the distal longitudinal end of the filter head 1210. The second circumferential sealing area 1232 is positioned toward the opposite longitudinal end of the filter head 1210. In the current example, the retainer ring 1212 is disposed in the filter cover assembly 1209 and is configured to resist the longitudinal translation of the filter assembly 1001 relative to the filter cover assembly 1209. The retainer ring 1212 can be configured to fix the fourth end cap 1130 in the filter head 1210.

[0186] In the current example, the filter cover assembly 1209 has a filter housing 1202 configured to receive a substantial portion of the filter assembly 1001. The filter housing 1202 extends from the filter head 1210 to the filter support platform 1264. The filter housing 1202 surrounds the secondary media assembly 1110. The filter housing 1202 is coupled to the filter head 1210 at a first longitudinal end and is coupled to the filter support platform 1264 at a second longitudinal end opposite the first longitudinal end. The filter housing 1202 can be constructed of a variety of materials and combinations of materials, including metal, plastic, mesh, etc. In some embodiments, the filter housing 1202 is configured to provide structural support to the secondary media assembly 1110.

[0187] It should be noted that in the current example system 1200, the first end cap 1020 of the primary filter element 1000 and the third end cap 1120 of the secondary filter element 1100 are coupled to the filter support platform 1264. The second end cap 1030 of the primary filter element 1000 and the fourth end cap 1130 of the secondary filter element 1100 are coupled to the filter head 1210. Therefore, in this example system 1200, the first end cap 1020 is vertically positioned below the second end cap 1030. In this example system 1200, the third end cap 1120 is vertically positioned below the fourth end cap 1130. The first end cap 1020 and the third end cap 1120 can define the first end 1003 of the filter assembly 1001. The second end cap 1030 and the fourth end cap 1130 can define the second end 1005 of the filter assembly 1001. In this example, the first end 1003 of the filter assembly 1001 is positioned vertically below the second end 1005 of the filter assembly 1001. However, in some embodiments, such as described earlier herein, the second end of the filter assembly may be positioned vertically below the first end of the filter assembly.

[0188] The flow tube 1040 is configured to be sealably coupled to the filter cap assembly 1209. The filter cap 1220 has a first tube connector 1214 configured to be sealably coupled to the second tube end 1044. In this particular example, the first tube connector 1214 sealably receives the second tube connector 1032 of the second end cap 1030. The first tube connector 1214 is configured to separate the second channel opening 1031 from the second tube opening 1043 within the filter head 1210. Other configurations are also contemplated for coupling the filter cap assembly 1209 to the filter assembly 1001.

[0189] The fluid tank 1260 has a fluid return conduit 1265 having a fluid return inlet 1266 to the system 1200. The filter passage 1004 extends from the fluid return inlet 1266 through the fluid return conduit 1265. The fluid return conduit 1265 and the filter support platform 1264 define a portion of the filter passage 1004. In particular, the filter support platform 1264 defines a fluid return interface 1269 that is configured to fluidly couple the fluid return conduit 1265 to the filter assembly 1001 around the filter passage 1004. The fluid return conduit 1265 is coupled to the filter support platform 1264, wherein the filter support platform 1264 also defines a portion of the filter passage 1004. Filter support platform 1264 is coupled to first end cap 1020 of primary filter element 1000 about first end cap opening 1021 such that filter passage 1004 extends through fluid return inlet 1266 , filter support platform 1264 , first end cap opening 1021 , first channel opening 1022 , and central channel 1016 of primary filter element 1000 .

[0190] The configuration consistent with the present example, in which the inlet to the filter passage 1004 of the filter element is positioned toward the bottom of the filter assembly 1001, advantageously limits aeration of the fluid as compared to a configuration in which the inlet to the filter passage is positioned toward the top of the filter assembly. In the former configuration, gravity on the fluid traveling from the top to the bottom of the filter element may cause aeration of the fluid as impact occurs between the fluid and the rest of the assembly.

[0191] The system 1200 also defines a portion of the exhaust passage 1002. The exhaust passage 1002 extends through the tank 1260 via one or more exhaust conduits 1262 through the third end cap opening 1124. The exhaust conduits 1262 extend from the exhaust tank inlet 1268 to the filter support platform 1264. The filter support platform 1264 fluidly couples the exhaust conduits 1262 and the third end cap opening 1124. In particular, the filter support platform 1264 defines an exhaust path interface 1267 that is configured to fluidly couple the exhaust conduits 1262 to the end cap gap 1126 between the third end cap 1120 and the primary filter element 1000. The filter support platform 1264 isolates the first channel opening 1022 from the end cap gap 1126 between the third end cap 1120 and the primary filter element 1000. In this example, the end cap gap 1126 between the third end cap 1120 and the primary filter element 1000 defines a portion of the exhaust passage within the filter assembly 1001. In this example, the flow area defined by the third end cap opening 1124 on the exterior of the flow tube 1040 defines the exhaust passage inlet of the filter assembly 1001 .

[0192] Drain passage 1002 extends from drain canister inlet 1268, through drain conduit 1262, through filter support platform 1264, to element gap 1118 defined between primary filter element 1000 and secondary filter element 1100, and radially outward through secondary media assembly 1110. Thus, in examples consistent with the present example, secondary filter element 1100 is a drain filter element.

[0193] The drain passage 1002 bypasses the primary media assembly 1010. In particular, the drain passage 1002 is separated from the filter passage 1004 upstream of the primary media assembly 1010. The drain conduit 1262 fluidly couples the drain passage 1002 to the drain filter element 1100, which is the secondary filter element 1100. The drain conduit 1262 extends from the drain tank inlet 1268 through the fluid cavity 1261 of the tank 1260 to the filter assembly 1001. In the present example, the inlet of the filter passage 1004 to the filter assembly 1001, which is the first channel opening 1022, and the inlet of the drain passage 1002 to the filter assembly 1001, which is the end cap gap 1126 between the third end cap 1120 and the primary filter element 1000, are toward the same longitudinal end of the filter assembly 1001. Similarly, the fluid return inlet 1266 is positioned toward the first end of the tank 1260, and the exhaust tank inlet 1268 is positioned toward the same end of the tank 1260. The specific configuration of the exhaust passage 1002 relative to the system 1200 may be as described above with reference to Figures 13 to 15 Various advantages have been discussed.

[0194] The system 1200 is configured to selectively define a bypass passage 1252 that bypasses the primary filter element 1000 (and in particular, the primary media assembly 1010). The bypass passage 1252 selectively extends from a location upstream of the primary media assembly 1010 along the filter passage 1004 through the secondary media assembly 1110 to the filter assembly outlet, wherein the filter assembly outlet is the downstream face 1102 of the secondary filter element 1100. The filtration system has a bypass valve 1250 that is disposed upstream of the primary media assembly 1010, between the filter passage 1004 and the discharge passage 1002 in the filter assembly 1001. In particular, the filter cap assembly 1209 has the bypass valve 1250. In the event that the fluid pressure in the filter passage 1004 exceeds a threshold value, the bypass valve 1250 selectively directs the fluid flow from the filter passage 1004 (upstream of the primary media assembly 1010) to the discharge passage 1002. Thus, the bypass fluid flow passes through the bypass passage 1252 into the exhaust passage 1002 and is filtered by the secondary media assembly 1110. This can be an advantage over a system without a filter for the bypass fluid flow. In some embodiments, the bypass valve 1250 can be omitted.

[0195] In this example, the filter cover assembly 1209 defines a portion of the discharge passage 1002, a portion of the filter passage 1004, and a bypass passage 1252. Under normal operating conditions, the filter cover assembly 1209 is configured to isolate the discharge passage 1002 from the filter passage 1004. However, at a pressure peak in the filter passage 1004 that reaches a threshold, the bypass valve 1250 opens to define the bypass passage 1252. The flow tube 1040 extends from the discharge passage defined by the filter support platform 1264 through the central channel 1016 to the discharge passage defined by the filter cover assembly 1209. Therefore, in this example, the bypass fluid flow is routed down to the first end 1003 of the filter assembly 1001 to merge with the discharge fluid flow. The second tube end 1044 of the flow tube 1040 defines a second inlet to the discharge passage 1002.

[0196] In the current system 1200, the filter cap assembly 1209 defines a fill port 1227 that is in fluid communication with the drain passage 1002. The fill port 1227 can be in selective fluid communication with the bypass passage 1252. In normal operation, the fill port 1227 is isolated from the filter passage 1004 within the filter cap assembly 1209. An advantage of configuring the fill port 1227 to be in fluid communication with the drain passage 1002 is that new fluid added to the system is filtered through the secondary media assembly 1110. In some embodiments, the fill port 1227 can be omitted.

[0197] The filter cover 1220 is removably disposed on the filter head 1210 across the fill port 1227. The filter cover 1220 can be selectively removed by a user to add a fluid (such as a hydraulic fluid) to the system 1200. In the current example, the removable cover 1220 and the filter cover assembly 1209 are frictionally engaged by a first circumferential sealing area 1230. Other coupling features may also be used to couple the filter cover 1220 to the filter head 1210, such as threads, bolts, magnets, etc.

[0198] Filter passage 1004 extends from fluid return conduit 1265 to first end cap 1020, and specifically to a first inlet to the filter element as first passage opening 1022 of first end cap 1020, through central passage 1016, and radially outward through primary media assembly 1010 and secondary media assembly 1110. Filter passage 1004 also extends through second end cap 1030 and into a portion of filter cover assembly 1209 to bypass valve 1250.

[0199] Although not currently depicted, it should be noted that the canister 1260 will typically have a fluid outlet configured to be in fluid communication with other system components, such as a fluid pump.

[0200] Fig. 20 Depicted with Fig.18 Another example tank system 1300 consistent with the example filter assembly of FIG. 1300 is similar to the example tank system 1300 of FIG. Fig.19 The described systems are generally consistent. However, in the current example, the discharge conduit 1362 at least partially surrounds the fluid return conduit 1365 around the central axis x. Thus, the discharge fluid is configured to enter the filter assembly 1001 around the end cap gap 1126 between the third end cap 1120 and the primary filter element 1000. The discharge path interface 1367 fluidly connects the discharge conduit 1362 and the flow tube 1040. The discharge path interface 1367 extends radially inward from the discharge conduit 1362. The discharge path interface 1367 extends radially into the fluid return conduit 1365. The discharge path interface 1367 can be partially defined by the filter support platform 1364. The discharge path interface 1367 extends longitudinally to the first tube end 1042 of the flow tube 1040.

[0201] Fig.21 1 is a partially sectional perspective view of a second sectional view of an example system 1600. System 1600 has a filter cap assembly 1609 and a filter assembly 1601 having a primary filter element 1400 and a secondary filter element 1500. System 1600 defines a filter passage 1604 extending through a primary media assembly 1410 of primary filter element 1400 and a secondary media assembly 1510 of secondary filter element 1500. System 1600 defines a drain passage 1602 configured to bypass primary media assembly 1410 and extend through secondary media assembly 1510. Drain passage 1602 is separate from filter passage 1604 in primary filter element 1400.

[0202] The filter assembly 1601 is configured to be disposed in a fluid cavity of a canister. The filter cap assembly 1609 is generally configured to receive the filter assembly 1601. Similar to the embodiments discussed above, the filter cap assembly 1609 can have a filter housing 1603 configured to receive a substantial portion of the filter assembly 1601. The filter cap assembly 1609 has a filter head 1610 configured to be coupled to the filter assembly 1601. The filter cap assembly 1609 also has a filter cap 1620 configured to be detachably coupled to the filter head 1610. The filter cap 1620 is coupled to the filter head 1610 via mating features, which can be similar to the mating features discussed elsewhere herein.

[0203] The example filter assembly 1601 can have a central axis extending in a longitudinal direction, as has been described herein. The primary filter element 1400 has: a primary media assembly 1410, which defines a central channel 1416; and a first end cap 1420, which is coupled to a first media end 1412 of the primary media assembly 1410. Although not currently visible, similar to other examples described herein, the primary filter element 1400 also typically has a second end cap, which is coupled to a second media end of the primary media assembly 1410. The primary media assembly 1410 is generally configured to filter a fluid and can be consistent with the description of the other media assemblies described above, and thus has a filter media 1411 and an optional structural support.

[0204] The first end cap 1420 is generally configured to retain the first media end 1412 of the primary media assembly 1410, such as via a media potting structure that may be consistent with the description above. The first end cap 1420 has a first circumferential sealing surface 1428 about the longitudinal axis x, which is configured to form a seal with the filter cover assembly 1609. The first circumferential sealing surface 1428 shares the central axis x of the primary media assembly 1410 and the central channel 1416. The first circumferential sealing surface 1428 can be a circumferential cavity configured to receive an elastomeric component (such as an o-ring). The first circumferential sealing surface 1428 can be consistent with other similar sealing surfaces described herein.

[0205] The first end cap 1420 defines a portion of the filter passage 1604 through the primary media assembly 1410. In particular, the first end cap 1420 defines a first end cap opening 1421 that extends in a longitudinal direction from the exterior of the filter assembly 1601 to the central passage 1416. In the current embodiment, a drain passage 1602 extends through the first end cap 1420. The drain passage 1602 is separated from the filter passage 1604 in the first end cap 1420. In particular, the first end cap 1420 defines a drain passage 1426 that extends from the filter cap assembly 1609 to the element gap 1518 between the primary media assembly 1410 and the secondary media assembly 1510. In particular, the first end cap 1420 has a first media encapsulation structure 1423a (which has been described in detail elsewhere herein) and an end cap plate 1423b that is longitudinally spaced from the first media encapsulation structure 1423a to define a drain passage 1426 therebetween. The end cover plate 1423b forms a seal with the filter cover assembly 1609.

[0206] The first end cap 1420 defines a tubular extension 1424 extending longitudinally outward from the first end cap 1420 around the discharge passage 1426. In particular, the tubular extension 1424 extends longitudinally outward from the end cap plate 1423b. The tubular extension 1424 is configured to form a seal with the filter cap assembly 1609 around the discharge passage 1602 to isolate the discharge passage 1602 from the filter passage 1604 upstream of the primary media assembly 1410. A second circumferential sealing surface 1429 is defined around an outer radial surface of the tubular extension 1424, but in some embodiments, the second circumferential sealing surface can be defined around an inner radial surface of the tubular extension.

[0207] Unlike some other embodiments herein, in this example, the entire central channel 1416 defines a portion of the filter passage 1604. Similarly, the entire first end cap opening 1421 defines a portion of the filter passage 1604. In the current example, the exhaust passage 1602 does not extend through the primary media assembly 1410, but rather bypasses the primary media assembly 1410 via the first end cap 1420. In the first end cap 1420, the exhaust passage 1602 has an exhaust passage inlet 1425 and an exhaust passage outlet 1427. The exhaust passage inlet 1425 is defined by the tubular extension 1424, and the exhaust passage outlet 1427 of the first end cap 1420 is defined by a portion of the first end cap 1420 adjacent to the element gap 1518. Similar to the embodiments discussed above, the exhaust passage 1602 is separated from the filter passage 1604 within the primary media assembly 1410. However, in this example, the drain passage 1602 and the filter passage 1604 are separate because the drain passage 1602 is external to the primary media assembly 1410 .

[0208] The second end cap is generally configured to retain a second media end of the filter media assembly and may have a second media potting structure as described herein. The second end cap is configured to block the central passage 1416 so that a filter passage extends through the filter media assembly.

[0209] The secondary filter element 1500 generally surrounds the primary filter element 1400. The secondary filter element 1500 has a secondary media assembly 1510 having a third end 1512 and a fourth end that is not visible. The third end 1512 is positioned toward the first end 1412 of the primary media assembly 1410, and the fourth end is positioned toward the second end of the primary media assembly 1410. The secondary media assembly 1510 defines a cavity 1516 extending from the third end 1512 to the fourth end. The cavity 1516 receives the primary filter element 1400. An element gap 1518 can be defined between the primary media assembly 1410 and the secondary media assembly 1510, as has been described herein. The secondary media assembly 1510 is generally configured consistent with the description of the other secondary filter media assemblies discussed above.

[0210] The third end cap 1520 is coupled to the third end 1512 of the secondary media assembly 1510 and is configured to be coupled to the filtration system. The third end cap 1520 has a third potting structure 1522 on one longitudinal end of the third end cap 1520. The third potting structure 1522 can be consistent with other potting structures described herein. The third end cap 1520 has a radial edge 1521 discussed in the previous example, which is on the opposite longitudinal end of the third end cap 1520 relative to the third potting structure 1522. The radial edge extends radially outward from the third end cap 1520 and is configured to be fixed by the cover assembly 1609. In particular, the retainer ring 1614 is configured to fix the third end cap 1520 in the filter cover assembly 1609.

[0211] The third end cap 1520 defines a third end cap opening 1524 configured to receive the primary filter element 1400. In this embodiment, the third end cap 1520 forms a fluid seal with the outer circumferential sealing surface of the first end cap 1420. In particular, each of the third end cap 1520 and the first end cap 1420 forms a seal with the retainer ring 1614 about the central axis, which forms a seal between the first end cap 1420 and the third end cap 1520.

[0212] Similar to previous embodiments already described herein, a fourth end cap is coupled to a fourth end of the secondary media assembly 1510. Consistent with previously described embodiments, the fourth end cap is configured to receive the fourth end of the secondary media assembly 1510. In the current example, the fourth end cap is configured to form a fluid barrier across the cavity 1516. Each of the drain passage 1602 and the filter passage 1604 extend radially outward through the secondary media assembly 1510. Thus, the secondary media assembly 1510 functions as a drain filter.

[0213] The current depiction does not reflect a bypass valve. However, in some alternative examples, a bypass valve can be disposed in the filter cap assembly 1609, between the filter passage 1604 and the discharge passage 1602. The bypass valve can define a bypass passage that selectively extends from the filter passage 1604 to the discharge passage 1602 to bypass the primary media assembly 1410. The bypass passage selectively extends from the filter passage 1604 through the secondary media assembly 1510 to the filter assembly outlet, wherein the filter assembly outlet is the downstream face of the secondary filter element 1500. In some embodiments, the filter cap 1620 is removable and defines a fill port. In some such embodiments, the fill port extends to the discharge passage 1602 and is isolated from the filter passage upstream of the primary media assembly 1410 (such as, in the filter cap assembly 1609).

[0214] The filter cover 1620 and the filter head 1610 are configured to form at least one seal around the filter assembly opening 1618 defined by the filter head 1610. The filter cover 1620 and the filter head 1610 define a first circumferential sealing area 1630 and a second circumferential sealing area 1632. The first circumferential sealing area 1630 is defined between the filter head 1610 and the filter cover 1620 about the central axis x toward a first longitudinal end of the filter head 1610. The second circumferential sealing area 1632 is defined between the filter head 1610 and the filter assembly 1601 toward an opposite longitudinal end of the filter head 1610 relative to the first circumferential sealing area 1630.

[0215] In the current example, retainer ring 1614 is disposed in filter cover assembly 1609 and is configured to resist longitudinal translation of a portion of filter assembly 1601 relative to filter cover assembly 1609. Retainer ring 1614 can be configured to secure a portion of filter assembly 1601 in filter head 1610. More specifically, in this example, retainer ring 1614 is configured to secure secondary filter element 1500 and filter housing 1603 relative to filter cover assembly 1609.

[0216] Filter cover assembly 1609 is configured to be removably coupled to the canister. In the current example, filter cover assembly 1609 is configured to be removably coupled to filter assembly 1601. Outer circumferential sealing surface 1529 forms a seal around third end cap 1520 with a corresponding structure of filter cover assembly 1609 (and more specifically, filter head 1610). In the current example, the corresponding structure of filter head 1610 is an inner radial sealing surface. In some alternative embodiments, the third end cap can define an inner circumferential sealing surface, and the corresponding structure of the filter head structure can be an outer circumferential sealing surface.

[0217] The filter cap 1620 and the filter head 1610 define a portion of the filter passage 1604 between the first circumferential seal area 1630 and the second circumferential seal area 1632. The filter cap assembly 1609 defines a fluid return conduit 1612 that defines a fluid return inlet 1613 to the filter passage 1604 of the system 1600. In this particular embodiment, the filter head 1610 defines the fluid return conduit 1612, but in some other embodiments, the filter cap 1620 may define the fluid return conduit 1612. In various embodiments, the filter passage 1604 is configured to receive hydraulic fluid from an implement in the hydraulic system that is returned to a fluid tank.

[0218] The filter cap assembly 1609 has a drain conduit 1662 that defines a drain canister inlet 1664 to the canister system 1600. The drain canister inlet 1664 is in fluid communication with the drain passage inlet 1425 of the filter assembly 1601.

[0219] Drain passage 1602 is generally separate from filter passage 1604 upstream of primary media assembly 1410. Drain passage 1602 is separate from filter passage 1604 in filter cap assembly 1609. Drain passage 1602 extends from drain canister inlet(s) 1664 through drain conduit 1662 to tubular extension 1424 into drain passage 1426 defined by first end cap 1420, radially outward from tubular extension 1424 to element gap 1518 between primary media assembly 1410 and secondary media assembly 1510, and radially outward through secondary media assembly 1510. Thus, in examples consistent with the present example, secondary filter element 1500 is a drain filter element.

[0220] The drain passage 1602 bypasses the primary media assembly 1410. A drain conduit 1662 fluidly couples the drain passage 1602 to a drain filter element, which is the secondary filter element 1500. In the current example, the filter inlet to the filter assembly 1601, which is the first end cap opening 1421, is on the same longitudinal end of the filter assembly 1601 as the drain passage inlet 1425 to the filter assembly 1601.

[0221] The specific configuration of the exhaust passage 1602 can have various advantages. For example, routing the exhaust conduit 1662 (and therefore, the exhaust passage 1602) to avoid the filter assembly 1601 can reduce the fluid pressure across the exhaust passage 1602, which reduces the fluid pressure on the motor housing (or other component housing upstream of the exhaust passage 1602).

[0222] The filter passage 1604 extends from the fluid return conduit 1612 to the first end cap 1420, and specifically to the element inlet which is the first end cap opening 1421 of the first end cap 1420. Thus, the filter passage 1604 extends from the fluid return conduit 1612, through the filter cap assembly 1609 and the first end cap 1420, through the central passage 1416, and radially outward through the primary media assembly 1410 and the secondary media assembly 1510.

[0223] While the presently depicted and presently discussed example has primary filter element 1400 and secondary filter element 1500, in various embodiments of the present technology secondary filter element 1500 may be omitted. The secondary filter element may be omitted where, for example, a separate exhaust filter is incorporated into the filter element.

[0224] Exemplary Embodiments

[0225] Embodiment 1. A filter element comprises: a filter media assembly having a first media end and a second media end and having a central channel from the first media end to the second media end; a first end cap connected to the first media end; a second end cap connected to the second media end; a discharge passage extending through the first end cap; and a filter passage extending from the central channel through the filter media assembly, wherein the discharge passage is isolated from the filter passage in the first end cap.

[0226] Embodiment 2. The filter element of any one of embodiments 1 and 3 to 17, wherein the drain passage extends through the central channel and the second end cap.

[0227] Embodiment 3. The filter element of any of embodiments 1-2 and 4-17, wherein the drain passage has a drain passage inlet extending through the first end cap and a drain passage outlet extending through the first end cap.

[0228] Embodiment 4. The filter element of any one of embodiments 1-3 and 5-17, wherein the filter passage further extends through the first end cap.

[0229] Embodiment 5. The filter element of any one of embodiments 1-4 and 6-17, further comprising a flow tube disposed in the central channel, wherein the flow tube contains the exhaust passage.

[0230] Embodiment 6. The filter element of any of embodiments 1-5 and 7-17, wherein the flow tube is coupled to the first end cap about the drain passage.

[0231] Embodiment 7. The filter element of any of embodiments 1-6 and 8-17, wherein the flow tube is coupled to the second end cap about the drain passage.

[0232] Embodiment 8. The filter element of any of Embodiments 1-7 and 9-17, wherein the flow tube is separate from the first end cap.

[0233] Embodiment 9. The filter element of any of Embodiments 1-8 and 10-17, wherein the drain passage has a drain passage inlet extending through the first end cap and a drain passage outlet extending through the second end cap.

[0234] Embodiment 10 The filter element of any of Embodiments 1-9 and 11-17, further comprising a drain media assembly defining a portion of the drain passage, wherein the drain media assembly is a drain passage outlet.

[0235] Embodiment 11. The filter element of any of Embodiments 1-10 and 12-17, wherein the drain passage outlet extends radially outward from the filter element.

[0236] Embodiment 12. The filter element of any of Embodiments 1-11 and 13-17, wherein the flow tube defines a drain passage outlet.

[0237] Embodiment 13. The filter element of any of Embodiments 1-12 and 14-17, wherein the filter passage inlet is positioned radially between the flow tube and the filter media assembly.

[0238] Embodiment 14. The filter element of any of Embodiments 1-13 and 15-17, wherein the second end cap blocks the filtration passage in the central channel.

[0239] Embodiment 15. The filter element of any of Embodiments 1-14 and 16-17, wherein the first end cap is configured to be positioned vertically above the second end cap.

[0240] Embodiment 16. The filter element of any of Embodiments 1-15 and 17, wherein the first end cap is configured to be positioned vertically below the second end cap.

[0241] Embodiment 17. The filter element of any of Embodiments 1-16, wherein the filter passage extends through the first end cap and the second end cap.

[0242] Embodiment 18. A filter element, comprising: a filter media assembly having a first media end and a second media end and having a central channel from the first media end to the second media end; a first end cap connected to the first media end, wherein the first end cap defines a first end cap opening; a second end cap connected to the second media end, wherein the second end cap defines a second end cap opening; and a flow tube having a first tube end and a second tube end, the flow tube defining a first tube opening on the first tube end and a central opening extending from the first tube end to the second tube end, wherein the flow tube is positioned in the central channel and the flow tube extends between the first end cap opening and the second end cap opening, wherein the flow tube and the filter media assembly define a first channel opening separated from the central opening, whereby the filter element has: a filter passage, which passes through the filter media assembly from the first channel opening via the central channel, wherein the first channel opening defines an inlet to the filter passage; and a discharge passage along the central opening of the flow tube.

[0243] Embodiment 19. The filter element of any of Embodiments 18 and 20 to 26, wherein the flow tube and the second end cap form a seal about the central opening, and wherein the flow tube and the first end cap are separate.

[0244] Embodiment 20. The filter element of any of Embodiments 18-19 and 21-26, wherein the flow tube extends in a longitudinal direction from the second end cap beyond the first end cap.

[0245] Embodiment 21. The filter element of any of Embodiments 18-20 and 22-26, wherein the flow tube forms a seal with the first end cap about the central opening, and the flow tube forms a seal with the second end cap about the central opening.

[0246] Embodiment 22. The filter element of any of Embodiments 18-21 and 23-26, wherein an outer diameter of the first channel opening is greater than an outer diameter of the first tube opening.

[0247] Embodiment 23. The filter element of any of Embodiments 18-22 and 24-26, further comprising an exhaust filter element having an exhaust filter inlet, wherein the flow tube is coupled to the exhaust filter element about the exhaust filter inlet.

[0248] Embodiment 24 The filter element of any of Embodiments 18-23 and 25-26, wherein the exhaust filter element is coupled to the second end cap.

[0249] Embodiment 25 The filter element of any of Embodiments 18-24 and 26, wherein the first channel opening extends circumferentially around the first tube opening.

[0250] Embodiment 26 The filter element of any one of Embodiments 18 to 25, wherein the first channel opening is a series of opening segments.

[0251] Embodiment 27. A filter system comprising: a primary filter element comprising: a primary media assembly having a first media end and a second media end and having a central passage from the first media end to the second media end; a first end cap coupled to the first media end; a second end cap coupled to the second media end; and a filter passage extending through the first end cap, the central passage, and the primary media assembly, wherein the filter passage has a filter passage inlet through the first end cap and an outlet through the primary media assembly; and a secondary filter element comprising: a secondary a primary media assembly having a third media end and a fourth media end and having a cavity extending from the third media end to the fourth media end; a third end cap coupled to the third media end of the secondary media assembly, wherein the third end cap has a third end cap opening, wherein the cavity and the third end cap opening are configured to receive the primary filter element; and a fourth end cap coupled to the fourth end of the secondary media assembly, wherein the filter assembly defines a discharge passage extending through the secondary filter element, wherein the discharge passage is separate from the filter passage within the primary media assembly.

[0252] Embodiment 28. The filter assembly of any one of Embodiments 27 and 29 to 45, wherein the drain passage extends through the first end cap, the second end cap, and the central channel.

[0253] Embodiment 29. The filter assembly of any one of embodiments 27-28 and 30-45, wherein the third end cap has an inner circumferential sealing surface configured to form a seal with the outer circumferential sealing surface of the first end cap.

[0254] Embodiment 30. The filter assembly of any one of Embodiments 27-29 and 31-45, wherein the assembly defines a gap between the first end cap and the third end cap.

[0255] Embodiment 31. The filter assembly of any one of Embodiments 27-30 and 32-45, wherein a gap between the first end cap and the third end cap defines a drain passage inlet.

[0256] Embodiment 32. The filter assembly of any one of Embodiments 27-31 and 33-45, further comprising a flow tube disposed in the central channel, wherein the flow tube contains the exhaust passage.

[0257] Embodiment 33. The filter assembly of any one of Embodiments 27-32 and 34-45, wherein the filter passage inlet is defined between the first end cap and the flow tube.

[0258] Embodiment 34. The filter assembly of any one of Embodiments 27-33 and 35-45, wherein the flow tube is coupled to the first end cap.

[0259] Embodiment 35. The filter assembly of any one of Embodiments 27-34 and 36-45, wherein the fourth end cap forms a fluid barrier across the cavity.

[0260] Embodiment 36. The filter assembly of any one of Embodiments 27-35 and 37-45, wherein the filter passage extends through the second end cap.

[0261] Embodiment 37. The filter assembly of any one of Embodiments 27-36 and 38-45, further comprising a spacer extending in the longitudinal direction between the fourth end cap and the second end cap.

[0262] Embodiment 38. The filter assembly of any one of Embodiments 27-37 and 39-45, wherein the fourth end cap and the second end cap define a flow gap that is a portion of the discharge passage from the second end cap to the secondary media assembly.

[0263] Embodiment 39. The filter assembly of any one of embodiments 27 to 38 and 40 to 45, further comprising an exhaust filter element having an exhaust filter inlet, wherein the exhaust filter element is along the exhaust passage and the exhaust filter element is an outlet of the exhaust passage.

[0264] Embodiment 40. The filter assembly of any one of Embodiments 27-39 and 41-45, wherein the exhaust filter is coupled to the second end cap and the fourth end cap.

[0265] Embodiment 41. A filter assembly according to any one of Embodiments 27 to 40 and 42 to 45, wherein the exhaust filter element includes an exhaust media assembly in fluid communication with the exhaust filter inlet, and wherein the primary media assembly has a higher particle filtration efficiency than the exhaust media assembly.

[0266] Embodiment 42. The filter assembly of any one of Embodiments 27-41 and 43-45, wherein the primary media assembly has a higher particle filtration efficiency than the secondary media assembly.

[0267] Embodiment 43. The filter assembly of any one of Embodiments 27-42 and 44-45, wherein the drain passage has a drain passage inlet defined by the first end cap.

[0268] Embodiment 44. The filter assembly of any one of Embodiments 27-43 and 45, wherein the drain passage has a drain passage inlet defined by the flow tube.

[0269] Embodiment 45. The filter assembly of any one of Embodiments 27 to 44, wherein the filter passage inlet extends circumferentially around the drain passage inlet.

[0270] Embodiment 46. A system comprises: a filter cover assembly having a filter passage; a primary filter element configured to be removably connected to the filter cover assembly, the primary filter element comprising a first end cap, a second end cap, and a primary media assembly extending from the first end cap to the second end cap, wherein the primary filter element has a first central channel in fluid communication with the filter passage; a discharge filter element connected to the filter cover assembly; and a discharge passage configured to extend to the discharge filter element and avoid the primary media assembly.

[0271] Embodiment 47. The system of any one of Embodiments 46 and 48 to 62, wherein the filter cover assembly defines a portion of the drain passage that is isolated from the filter passage.

[0272] Embodiment 48. The system of any one of Embodiments 46-47 and 49-62, wherein the exhaust passage is configured to bypass the primary media assembly through the first central passage.

[0273] Embodiment 49. A system according to any one of Embodiments 46 to 48 and 50 to 62, further comprising a secondary filter element having a third end cap, a fourth end cap, and a secondary media assembly extending from the third end cap to the fourth end cap, wherein the secondary filter element has a second center channel extending from the third end cap through the secondary media assembly, wherein the second center channel is configured to receive the primary filter element.

[0274] Embodiment 50. The system of any one of Embodiments 46-49 and 51-62, wherein the exhaust passage extends to a gap defined between the primary media assembly and the secondary media assembly.

[0275] Embodiment 51. A system according to any one of embodiments 46 to 50 and 52 to 62, wherein the third end cap is configured to form a seal with the first end cap.

[0276] Embodiment 52. The system of any one of Embodiments 46-51 and 53-62, wherein the exhaust filter element is the secondary filter element.

[0277] Embodiment 53. The system of any one of Embodiments 46-52 and 54-62, further comprising a flow tube extending through the first central channel.

[0278] Embodiment 54. The system of any one of Embodiments 46-53 and 55-62, wherein the exhaust passage extends through the third end cap.

[0279] Embodiment 55. The system of any one of Embodiments 46-54 and 56-62, wherein the exhaust passage extends through the fourth end cap.

[0280] Embodiment 56. The system of any one of Embodiments 46-55 and 57-62, wherein the flow tube is coupled to the filter cap assembly about the drain passage.

[0281] Embodiment 57. The system of any one of Embodiments 46-56 and 58-62, wherein the flow tube is coupled to the filter cap assembly about the bypass passage.

[0282] Embodiment 58. The system of any of Embodiments 46-57 and 59-62, wherein the exhaust filter element is coupled to the second end cap.

[0283] Embodiment 59. The system of any one of Embodiments 46-58 and 60-62, wherein the filter cap assembly further comprises a fill port in fluid communication with the drain passage, and a removable cap disposed on the fill port.

[0284] Embodiment 60. The system of any one of Embodiments 46-59 and 61-62, further comprising a bypass valve disposed between the exhaust passage and the filter passage.

[0285] Embodiment 61. The system of any one of Embodiments 46-60 and 62, wherein the filter cover assembly comprises a filter cover and a filter head, wherein the filter cover and the filter head are coupled.

[0286] Embodiment 62. The system of any one of Embodiments 46-61, wherein the filter cap assembly comprises a filter cap and a filter head structure, wherein the filter head structure is defined by a can and the filter cap is coupled to the filter head structure.

[0287] Embodiment 63. A hydraulic system comprising: a primary media component; a secondary media component that is in fluid communication with the primary media component; a filter assembly outlet that is downstream of the secondary media component; a filter passage that extends through the primary media component, the secondary media component, and the filter assembly outlet; and a drain passage that extends through the secondary media component and the filter assembly outlet, wherein the drain passage avoids the primary media component.

[0288] Embodiment 64. The hydraulic system of any one of Embodiments 63 and 65 to 75, further comprising a bypass passage selectively extending from the filter passage through the secondary media assembly and the filter assembly outlet, wherein the bypass passage bypasses the primary media assembly.

[0289] Embodiment 65. The hydraulic system of any one of Embodiments 63-64 and 66-75, wherein the secondary media component is positioned downstream of the primary media component in the filter passage.

[0290] Embodiment 66. The hydraulic system according to any one of Embodiments 63 to 65 and 67 to 75 further includes a primary filter element, which includes: a primary media assembly having a first media end, a second media end, and a central channel from the first media end to the second media end; a first end cover connected to the first media end; and a second end cover connected to the second media end.

[0291] Embodiment 67. The hydraulic system of any one of Embodiments 63-66 and 68-75, wherein the drain passage extends through the first end cap and the second end cap of the primary filter element.

[0292] Embodiment 68. The hydraulic system according to any one of Embodiments 63 to 67 and 69 to 75, further includes a secondary filter element, the sub-primary filter element including: the secondary media assembly having a third media end and a fourth media end and having a cavity extending from the third media end to the fourth media end; a third end cover connected to the third media end of the secondary media assembly, wherein the third end cover has a third end cover opening, wherein the cavity and the third end cover opening are configured to receive the primary filter element; and a fourth end cover connected to the fourth end of the secondary media assembly.

[0293] Embodiment 69. The hydraulic system of any one of Embodiments 63-68 and 70-75, wherein the drain passage extends through the fourth end cap of the secondary filter element.

[0294] Embodiment 70. The hydraulic system of any one of Embodiments 63-69 and 71-75, wherein the drain passage does not extend through the primary media component.

[0295] Embodiment 71. A hydraulic system according to any one of embodiments 63 to 70 and 72 to 75, wherein the third end cover has an inner circumferential sealing surface, and the inner circumferential sealing surface is configured to form a seal with the outer circumferential sealing surface of the first end cover.

[0296] Embodiment 72. The hydraulic system of any one of Embodiments 63 to 71 and 73 to 75, wherein the third end cover and the first end cover define a drain passage therebetween.

[0297] Embodiment 73. The hydraulic system of any one of Embodiments 63-72 and 74-75, further comprising a fill port passage extending through the secondary media assembly and the filter assembly outlet, wherein the fill port passage bypasses the primary media assembly.

[0298] Embodiment 74. The hydraulic system of any one of Embodiments 63 to 73 and 75, wherein the fill port passage and the bypass passage merge into the fluid flow passage.

[0299] Embodiment 75. A hydraulic system according to any one of Embodiments 63 to 74, wherein the fill port passage and the bypass passage merge with the exhaust passage.

[0300] Embodiment 76. A tank system comprises: a tank body, which defines a fluid cavity, a fluid outlet, a filter assembly opening, a fluid return inlet and a discharge tank body inlet; a filter assembly, which is disposed in the fluid cavity and connected to the tank body around the filter assembly opening; a filter cover assembly, which is connected to the filter assembly and the tank body; a filter passage, which extends from the fluid return inlet through the tank body to the filter assembly; and a discharge conduit, which extends from the discharge tank body inlet through the fluid cavity to the filter assembly, wherein the discharge passage is defined as extending from the discharge tank body inlet through the discharge conduit to the filter assembly.

[0301] Embodiment 77. The canister system of any one of Embodiments 76 and 78 to 85, wherein the filter cap assembly is positioned toward a first end of the canister and the drain canister inlet is defined toward an opposite end of the canister.

[0302] Embodiment 78. The tank system of any one of Embodiments 76-77 and 79-85, wherein the tank defines a top end and a bottom end, and the drain tank inlet is defined toward the bottom end of the tank.

[0303] Embodiment 79. The canister system of any one of Embodiments 76 to 78 and 80 to 85, wherein the filter cap assembly defines the fluid return inlet.

[0304] Embodiment 80. The tank system of any one of embodiments 76 to 79 and 81 to 85, wherein the tank has a top end and a bottom end, and the tank defines the fluid return inlet toward the bottom end.

[0305] Embodiment 81. The canister system of any one of Embodiments 76-80 and 82-85, wherein the filter assembly comprises a primary media assembly and a secondary media assembly downstream of the primary media assembly.

[0306] Embodiment 82. The canister system of any one of Embodiments 76-81 and 83-85, wherein the filter passage extends from the fluid return inlet through the primary media assembly and through the secondary media assembly.

[0307] Embodiment 83. The canister system of any one of Embodiments 76-82 and 84-85, wherein the exhaust passage bypasses the primary media assembly and extends through the secondary media assembly.

[0308] Embodiment 84. The canister system of any one of Embodiments 76 to 83 and 85, wherein the filter cap assembly comprises a filter cap and a filter head, wherein the filter cap and the filter head are coupled.

[0309] Embodiment 85. The canister system of any one of Embodiments 76 to 84, wherein the filter cap assembly comprises a filter cap and a filter head structure, wherein the filter head structure is defined by the canister and the filter cap is coupled to the filter head structure.

[0310] Embodiment 86. A filter system comprising: a primary media component; a secondary media component that is in fluid communication with the primary media component; a filter passage outlet that is downstream of the secondary media component; a filter passage that extends through the primary media component, the secondary media component, and the filter passage outlet; a discharge passage outlet that is configured to merge with the filter passage outlet; a discharge passage that extends to the discharge passage outlet; a discharge media component that is disposed across the discharge passage; and a fluid flow passage that selectively extends to the discharge passage upstream of the discharge media component.

[0311] Embodiment 87. The filter assembly of any one of Embodiments 86 and 88 to 74, wherein the fluid flow passage is a bypass passage that selectively extends from the fluid flow passage to the drain passage, wherein the bypass passage is upstream of the primary media assembly.

[0312] Embodiment 88. The filter assembly of any one of Embodiments 86-87 and 89-94, wherein the fluid flow passage is a fill port passage that is selectively openable by a user.

[0313] Embodiment 89. The filter assembly of any one of Embodiments 86-88 and 90-94, wherein the secondary media assembly is positioned downstream of the primary media assembly in the filter passage.

[0314] Embodiment 90. The filter assembly according to any one of Embodiments 86 to 89 and 91 to 94, further comprising a primary filter element, the primary filter element comprising: the primary media assembly having a first media end, a second media end, and a central channel from the first media end to the second media end; a first end cap connected to the first media end; and a second end cap connected to the second media end.

[0315] Embodiment 91. The filter assembly according to any one of Embodiments 86 to 90 and 92 to 94, further comprising a secondary filter element, the secondary filter element comprising: the secondary media assembly having a third media end and a fourth media end and having a cavity extending from the third media end to the fourth media end; a third end cap connected to the third media end of the secondary media assembly, wherein the third end cap has a third end cap opening, wherein the cavity and the third end cap opening are configured to receive the primary filter element; and a fourth end cap connected to the fourth end of the secondary media assembly.

[0316] Embodiment 92. The filter assembly of any one of Embodiments 86-91 and 93-94, wherein the third end cap has an inner circumferential sealing surface configured to form a seal with the outer circumferential sealing surface of the first end cap.

[0317] Embodiment 93. The filter assembly of any one of Embodiments 86-92 and 94, further comprising a bypass passage that selectively extends to the secondary media assembly and bypasses the primary media assembly.

[0318] Embodiment 94. The filter assembly of any one of Embodiments 86-93, further comprising a fill port passage extending through the secondary media assembly and the filter assembly outlet, wherein the fill port passage bypasses the primary media assembly.

[0319] It should also be noted that, as used in this specification and the appended claims, the phrase "configured to" describes a system, device, or other structure that is configured to perform a specific task or adopt a specific structure. The word "configured to" can be used interchangeably with similar words such as "arranged to", "constructed to", "made to", and the like.

[0320] All publications and patent applications in this specification indicate the level of ordinary technicians in the field of this technology. All publications and patent applications are incorporated herein by reference, and the extent of the citation is as if each individual publication or patent application is clearly and individually indicated by reference. In the event of any inconsistency between the disclosure of the present application and the disclosure of any document incorporated herein by reference, the disclosure of the present application shall prevail.

[0321] This application is intended to cover adaptations or variations of the present subject matter.It is to be understood that the above description is intended to be illustrative and not restrictive, and that the claims are not limited to the illustrative embodiments as set forth herein.

Claims

1. A filter element comprising: a filter media assembly having a first media end and a second media end and having a central passage from the first media end to the second media end; a first end cap coupled to the first media end; a second end cap coupled to the second media end; a flow tube disposed in the central passage, wherein the flow tube includes a first tube opening located at a first tube end and a central opening extending from the first tube end to a second tube end, wherein the central opening defines a discharge passage, wherein the first tube opening defines a discharge passage inlet in direct fluid communication with the central opening, wherein the discharge passage extends through the first end cap; a filter passage extending through the opening of the first end cap to the central passage and extending through the filter media assembly, wherein the drain passage is separated from the filter passage in the first end cap; as well as The drain passage and the filter passage are not in fluid communication via the bypass valve.

2. The filter element according to claim 1, wherein The drain passage extends through the central passage and the second end cap.

3. The filter element according to claim 1, wherein The drain passage has a drain passage inlet extending through the first end cover and a drain passage outlet extending through the first end cover.

4. The filter element according to claim 1, wherein The filter passage further extends through the first end cap.

5. The filter element of claim 1, wherein: The flow tube is coupled to the first end cap about the discharge passage.

6. The filter element of claim 1, wherein: The flow tube is coupled to the second end cap about the discharge passage.

7. The filter element of claim 1, wherein: The flow tube is separated from the first end cap.

8. The filter element of claim 1, wherein: The drain passage has a drain passage inlet extending through the first end cover and a drain passage outlet extending through the second end cover.

9. The filter element of any one of claims 1 to 8, further comprising a drain media assembly defining a portion of the drain passage, wherein: The exhaust media component is an exhaust passage outlet.

10. The filter element according to claim 9, wherein The exhaust passage outlet extends radially outward from the filter element.

11. The filter element according to any one of claims 1 to 8, wherein The flow tube defines a discharge passage outlet.

12. The filter element according to claims 1 to 8, wherein The filter passage inlet is positioned radially between the flow tube and the filter media assembly.

13. The filter element according to any one of claims 1 to 8, wherein The second end cap blocks the filter passage in the central channel.

14. The filter element according to any one of claims 1 to 8, wherein The first end cap is configured to be positioned vertically above the second end cap.

15. The filter element according to any one of claims 1 to 8, wherein The first end cap is configured to be positioned vertically below the second end cap.

16. The filter element according to any one of claims 1 to 8, wherein The filter passage extends through the first end cap and the second end cap.

17. A filter element comprising: a filter media assembly having a first media end and a second media end and having a central passage from the first media end to the second media end; a first end cap coupled to the first media end, wherein the first end cap defines a first end cap opening; a second end cap coupled to the second media end, the second end cap defining a second end cap opening; and a flow tube having a first tube end and a second tube end, the flow tube defining a first tube opening on the first tube end and a central opening extending from the first tube end to the second tube end, wherein the flow tube is positioned in the central passage and the flow tube extends between the first end cap opening and the second end cap opening, wherein the flow tube and the filter media assembly define a first passage opening separate from the central opening, whereby the filter element has: a filter passage extending through the filter media assembly from the first passage opening through the central passage, wherein the first passage opening defines an inlet to the filter passage, and a discharge passage opening along a center of the flow tube; and Therein, the first channel opening is configured to be kept fluidically separated from the first tube opening.

18. The filter element of claim 17, wherein: The flow tube and the second end cap form a seal about the central opening, and wherein the flow tube and the first end cap are decoupled.

19. The filter element of claim 17, wherein: The flow tube extends from the second end cap beyond the first end cap in a longitudinal direction.

20. The filter element of claim 17, wherein: The flow tube forms a seal with the first end cap around the central opening, and the flow tube forms a seal with the second end cap around the central opening.

21. The filter element of claim 17, wherein: The outer diameter of the first channel opening is greater than the outer diameter of the first tube opening.

22. The filter element of any one of claims 17 to 21, further comprising an exhaust filter element having an exhaust filter inlet, wherein: The flow tube is coupled to the exhaust filter element about the exhaust filter inlet.

23. The filter element of claim 22, wherein: The exhaust filter element is coupled to the second end cap.

24. A filter element according to any one of claims 17 to 21, wherein The first channel opening extends circumferentially around the first tube opening.

25. A filter element according to any one of claims 17 to 21, wherein The first passage opening is a series of opening segments.

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