Systems and methods for attaching and retaining a filter element to a drive shaft

Abstract

Rotating filter element (102, 1502) comprising: a first end plate (108), a second end plate (110), a filter medium (106) disposed between the first end plate (108) and the second end plate (110), and a filter element sleeve or bushing (112, 1506) configured to receive a drive shaft (104, 1504) of a filtration system when the rotating filter element (102, 1502) is installed in the filtration system, wherein the filter element sleeve or bushing (112, 1506) has a projection (404) projecting radially inward, wherein the filter element sleeve or bushing (112, 1506) includes a relief portion (606) providing a radius at an inside corner of the projection (404), wherein the projection (404) cooperates with the drive shaft (104, 1504) of the filtration system to transmit rotation from the drive shaft (104, 1504) to the rotating filter element (102, 1502), wherein the rotating filter element (102, 1502) is arranged to separate a suspended liquid from a fluid.

Description

TECHNICAL FIELD

[0001] The present application relates to rotating filter elements. BACKGROUND

[0002] During operation of an internal combustion engine, a portion of the combustion gases can flow out of the combustion cylinder and into the engine crankcase. These gases are often referred to as "bypass." Bypass gases include a mixture of aerosols, oils, and air. If vented directly to the atmosphere, bypass gases can be harmful to the environment. Accordingly, bypass gases are typically removed from the crankcase by means of a crankcase ventilation system. The crankcase ventilation system may direct the bypass gases through a drift eliminator or coalescer (i.e., a coalescing filter element) to remove much of the aerosols and oils contained in the bypass gases. The coalescer includes a filter media.The filtered leakage gases are then either vented to the atmosphere (in open crankcase ventilation systems) or returned to the air intake for the internal combustion engine for further combustion (in closed crankcase ventilation systems).

[0003] Some crankcase ventilation systems utilize rotating coalescers, which increase the filtration efficiency of the coalescing filter elements by rotating the filter media during filtration. In rotating filter cartridges, contaminants (e.g., oil droplets suspended in and carried by bypass gases) are separated within the filter media of the filter cartridge by the particle capture mechanisms of inertial impact, interception, diffusion, and gravitational forces acting on the fibers. By rotating the filter media, inertial impact and gravitational forces are amplified by additional centrifugal force. Furthermore, the rotation of the filter cartridge can create a pumping effect, reducing the pressure drop through the filtration system. Rotating filter cartridges can include fabric filters as well as centrifugal separation devices.

[0004] Rotating filter elements require periodic maintenance and replacement. Accordingly, rotating filter elements must be removably mounted and held on a drive shaft. When the filter element is installed on the drive shaft, the drive shaft imparts rotation to the filter element during filtering operations. When the filter element is removed from the drive shaft, it can be serviced and reinstalled on the drive shaft, or a new filter element can be installed on the drive shaft.

[0005] DE 11 2011 103 116 T5 discloses a gas-liquid rotary separator including a first and second set of multiple detent surfaces on a rotary drive member and a driven annular rotary separation filter element engagingly interacting in a locking mated toothed relationship to effect rotation of the separation filter element by the rotary drive member.

[0006] US 2003 / 0 116 496 A1 discloses a rotating high-shear disc filter that is hollow inside and made of a porous material. The disc is mounted on a hollow shaft connected to a vacuum source outside the filter, allowing the filtrate to pass to a receiver. Elongated slots are located in the wall of the shaft, allowing the filtrate to pass from the disc. The shaft provides the rotating force for the discs.

[0007] US 4 975 188 A discloses a rotating filter device having a stack of porous filter discs mounted on a vertical, rotatable hollow shaft and located in a chamber, the shaft having a plurality of openings leading to the hollow bore of the shaft. SUMMARY

[0008] An exemplary embodiment relates to a filtration system. The filtration system includes a housing having an inlet and an outlet. The filtration system includes a drive mechanism including a drive shaft with a flat portion. The filtration system further includes a rotating filter element disposed within the housing and in fluid communication with the inlet and the outlet. The rotating filter element is configured to separate a suspended liquid from a fluid received through the inlet. The rotating filter element includes a first end plate, a second end plate, and a filter media disposed between the first end plate and the second end plate. The rotating filter element further includes a filter element sleeve or bushing configured to receive the drive shaft.The filter element sleeve or bushing has a projection that projects radially inward. The filter element sleeve or bushing includes a relief portion that provides a radius at an inside corner of the projection. The projection cooperates with the flat portion of the rotating shaft to transmit rotation from the rotating shaft to the rotating filter element.

[0009] Another exemplary embodiment relates to a rotating filter element. The rotating filter element includes a first end plate, a second end plate, and a filter media disposed between the first end plate and the second end plate. The rotating filter element further includes a filter element sleeve or bushing configured to receive a drive shaft of a filtration system when the rotating filter element is installed in the filtration system. The filter element sleeve or bushing includes a protrusion that protrudes radially inward. The protrusion cooperates with a rotating shaft of the filtration system to transmit rotation from the rotating shaft to the rotating filter element. The rotating filter element is configured to separate a suspended liquid from a fluid.

[0010] These and other features, as well as the organization and manner of operation, will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like elements have like reference numerals throughout the various drawings described below. Character list Fig. 1 and Fig. 2 show cross-sectional views of a filter element installed over a drive shaft and secured to the drive shaft according to an exemplary embodiment. Fig. 3 to Fig. 10 show different views illustrating how the rotating filter element of Fig. 1 and Fig. 2 on the rotating shaft of Fig. 1 and Fig. 2 is installed and interacts with it. Fig. 11 to Fig. 14 show different cross-sectional views of the filter element of Fig. 1, which is attached to the drive shaft, and the filter element positioning during maintenance operations. Fig. 15 shows a cross-sectional view of a filter element installed over the drive shaft according to another exemplary embodiment. Fig. 16 shows a cross-sectional view of the filter element of Fig. 15, which is installed above the drive shaft. Fig. 17 shows a perspective view of the drive shaft of Fig. 15. Fig. 18 shows a plan view of a filter element sleeve of the filter element of Fig. 15. Fig. 19, Fig. 20 and Fig. 21 each show views of the drive shaft connected to the filter element sleeve of the filter element of Fig. 15 interacts. DETAILED DESCRIPTION

[0011] Referring generally to the figures, a mounting and retention mechanism for removably securing a rotating filter element to a drive shaft is described. The rotating filter element includes a filter media driven by a drive mechanism that rotates the drive shaft. The filter element is removably attached to the drive shaft so that the filter element and filtration system can be periodically replaced and / or serviced. According to various embodiments, the drive shaft includes a flat portion that cooperates with a mating portion or projection of the filter element sleeve or bushing of the rotating filter element.The filter element sleeve receives the flat portion of the drive shaft and provides surface contact between the rotating drive shaft and the filter element sleeve, reducing potential wear and allowing installation and removal of the rotating filter element. The filter element sleeve or bushing includes a relief portion in the root radius area of ​​the radial projection that reduces wear on the sleeve or bushing and promotes surface contact between the flat portion of the rotating drive shaft and the flat surface of the radial projection. In some arrangements, the flat portion of the drive shaft includes a chamfered or rounded edge that provides the relief or gap between the flat edges of the drive shaft and the root radius of the projection of the sleeve or bushing.

[0012] The filter element can be removed from and installed over the drive shaft without the use of special tools. An O-ring can be installed between the drive shaft and the filter element sleeve to prevent the filter element from falling off the drive shaft due to gravity and to prevent gases from bypassing the filter element through the gap between the drive shaft and the bushing or sleeve. The O-ring is compressed, allowing the drive shaft to thermally expand during thermal cycling without placing axial stress on the bearings. After the filter element is installed, a gap is formed between the drive shaft and an inner race of the lower filter bearing.

[0013] Referring to Fig. 1 shows a cross-sectional view of a filter element 102 installed over a drive shaft 104. The filter element 102 includes a filter media 106 disposed between first and second end caps 108 and 110. The filter element 102 includes a filter element sleeve 112 configured to receive and surround the drive shaft 104. In some arrangements, the filter element sleeve 112 is a bushing. The drive shaft 104 is rotated by a drive mechanism, such as an electric motor 114. During installation, the filter element 102 is passed over the drive shaft 104 in the direction of arrow 116.

[0014] Referring to Fig. Figure 2 shows a cross-sectional view of the filter element installed over the drive shaft 104. As shown, the drive shaft 104 may be provided with an O-ring 117. The O-ring 117 prevents the filter element 102 from falling off the drive shaft 104 due to gravity and prevents gases from passing past the filter element 102. The O-ring 117 compresses, allowing the drive shaft 104 to expand under thermal expansion during thermal cycling without placing axial stress on the bearings. In some arrangements, the O-ring 117 is replaced with a retaining snap ring, which provides a stronger holding force than the O-ring 117 to hold the filter element 102 axially on the drive shaft 104.

[0015] Fig. 3 is a perspective view of the drive shaft 104. The drive shaft 104 includes a flat portion 302. In some arrangements, the flat portion 302 provides a portion of the drive shaft 104 with a D-shaped cross-sectional profile. As described in more detail below, the flat portion 302 provides a drive surface that cooperates with a mating surface of the filter element sleeve 112 to transmit rotation from the drive shaft 104 to the filter element 102 (e.g., as shown in Fig. 5 and Fig. 6).

[0016] Referring to Fig. 4 is a perspective view of the filter element sleeve 112. The filter element sleeve 112 includes a sleeve boss 404. The sleeve boss 404 is a radially inwardly projecting protrusion that cooperates with the flat portion 302 of the drive shaft 104 to transmit rotation from the drive shaft 104 to the filter element 102 (e.g., as shown in Fig. 5, Fig. 6 and Fig. 10).

[0017] As in Fig. 5, Fig. 6 and Fig. 10, the filter element 102 is installed over the drive shaft 104. The flat portion 302 cooperates with the sleeve projection 404 to provide a drive interface between the drive shaft 104 and the filter element sleeve 112. The sleeve projection 404 provides a raised flat surface that makes surface contact (as opposed to point or line contact) with the flat portion 302 of the drive shaft 104 when the drive shaft 104 applies torque to the filter element 102. Accordingly, when the drive shaft 104 rotates in the direction of arrow 602, the filter element 102 also rotates in the direction of arrow 602. As shown in Fig. 9, in some arrangements or rotational orientations of the filter element 102, there is a gap between the flat portion 302 and the mating flat drive surface of the sleeve projection 404. These surfaces (i.e., the flat portion 302 and the mating flat drive surface of the sleeve projection 404) can only be in contact if they are parallel when the drive shaft 104 rotates to the flat surface of the sleeve projection 404.

[0018] In some arrangements, the drive shaft 104 includes a chamfer 604 adjacent the flat portion 302 that provides a relief or gap to the root radius of the sleeve projection 404. In some arrangements, the filter element sleeve 112 includes a relief portion 606 adjacent the sleeve projection. The relief portion 606 also has a radius at an inside corner of the sleeve projection 404 that reduces mechanical stress on the sleeve projection 404 during operation. The chamfer 604 and the relief portion 606 are in Fig. 4 and Fig. 5 in more detail. As in Fig. 8, the relief portion 606 extends over an entire axial length of the filter element sleeve 112. However, the sleeve projection 404 does not extend over the entire axial length of the filter element sleeve 112 in order to allow an axial portion of the drive shaft 104, which is not flattened, to cooperate with an upper portion of the filter element sleeve 112 (e.g., as shown in Fig. 2) to limit axial movement of the filter element 102 relative to the drive shaft 104. In addition, the relief portion 606 in the filter element sleeve 112 and the recesses where the drive shaft 104 meets the round part of the filter element sleeve 112 (i.e., the base of the filter element sleeve 112) form "dirt pockets" when viewed from the top of the filter element 102. These dirt pockets can collect dirt particles, thereby preventing migration of wear particles, for example, dirt particles originating from the coil spring 1304 above the element (as shown in Fig. 13 and Fig. 14).

[0019] In other arrangements, the filter element sleeve 112 includes a relief portion 606, while the drive shaft 104 does not include a bevel 604. This arrangement is shown in Fig. 9 and Fig. 10. In such arrangements, there is a gap between the drive shaft 104 and the filter element sleeve 112 during installation of the filter element 102 and no gap when the drive shaft 104 rotates into the flat portion of the sleeve boss 404 during operation.

[0020] Referring to Fig. 11 to Fig. 14 shows various cross-sectional views of the filter element 102. In particular, Fig. 11, the filter element 102 is installed over the drive shaft 104. The O-ring 117 fits between the drive shaft 104 and the filter element sleeve 112. The O-ring is arranged in a narrowed section 702 of the drive shaft 104 (as shown in Fig. 7). When the filter element 102 is in the installed position (as shown in Fig. 11), the O-ring 117 is adjacent to a bearing 1102 that receives a free end of the drive shaft 104. The O-ring 117 creates friction between the drive shaft 104 and the filter element 102, which prevents the filter element 102 from falling off the drive shaft 104 during installation and maintenance (e.g., when the top cover 1104 or the filter element 102 is lifted off the housing 1106, as shown in Fig. 11, or placed back into the housing 1106). In addition, installing the O-ring 117 over the drive shaft 104 does not require any special tools. When the filter element 102 is installed over the drive shaft, the filter element 102 is pressed over the drive shaft 104 in the direction of the arrows 1302 (e.g., as shown in Fig. 13). This compresses the coil spring 1304 and the groove for the O-ring (e.g. as shown in Fig. 14) on the drive shaft 104 so that the O-ring 116 can be installed on the drive shaft, which holds the filter element 102 on the drive shaft 104 in the axial direction. The O-ring 117 is held in a free state (as shown in Fig. 13) when the filter element 102 is in the installed position. The O-ring 117 helps prevent wear particles from entering the bearing 1102. In addition, the O-ring 117 forms a seal between the filter element sleeve 112 and the drive shaft 104, preventing gases from bypassing the filter element through the openings between the drive elements of the filter element sleeve 112 and the drive shaft 104.

[0021] In the installed position, a coil spring 1304 surrounding the drive shaft 104 (or other form of biasing element) is in a first state. The coil spring 1304 is pre-assembled to the drive shaft 104 such that the top of the coil spring 1304 contacts the inner race of the motor bearing, and is held axially to the drive shaft 104 with an e-retaining clip that cooperates with a groove on the drive shaft 104. In the first state, the e-retaining clip comes into contact with the second end cap 110 and the top of the filter element sleeve 112. To remove or service the O-ring 117, the filter element 102 can be rotated along the direction of arrows 1302 (e.g., as shown in Fig. 13) beyond the installed position to expose the O-ring 117, as shown in Fig. 14. In such a position, the coil spring 1304 is in a second state. In the second state, the coil spring 1304 is compressed more than in the first state. In the second state, the e-retaining clamp of the coil spring 1304 abuts the second end cap 110 and biases the filter element back to the installed position of Fig. 13.

[0022] Referring to Fig. 15 to Fig. 21, a filtration system 1500 is shown including a filter element 1502 and a drive shaft 1504 according to an exemplary embodiment. Fig. Figure 15 shows a cross-sectional view of the filter element 1502 installed over the drive shaft 1504. Fig. Figure 16 shows a cross-sectional view of the filter element 1502 installed over the drive shaft 1504. Fig. 17 shows a perspective view of the drive shaft 1504. Fig. 18 shows a top view of a filter element sleeve 1506 of the filter element 1502. Fig. 19, Fig. 20 and Fig. 21 each show views of the drive shaft 1504, which interacts with the filter element sleeve 1506.

[0023] The filter element 1502 and the drive shaft 1504 are the filter element 102 and the drive shaft 104 of Fig. 1 to Fig. 14. Accordingly, the same numbering is used to identify the same components between Fig. 1 to Fig. 14 and Fig. 15 to Fig. 21. As best described in Fig. 15 and Fig. 16, the filter element 1502 includes a filter media 106 disposed between first and second end caps 108 and 110. The filter element 1502 includes a filter element sleeve 1506 configured to receive and surround the drive shaft 1504. In some arrangements, the filter element sleeve 1506 is a bushing. The drive shaft 1504 is rotated by a drive mechanism, such as an electric motor 114. During installation, the filter element 1502 is passed over the drive shaft 1504 in the direction of arrow 116.

[0024] As in Fig. 17, the drive shaft 1504 includes a drive portion 1702. The drive portion 1702 includes a plurality of flat surfaces forming a hexagonal cross-section on the drive portion 1702 of the drive shaft 1504. As described in more detail below, the flat surfaces of the drive portion 1702 provide drive surfaces that cooperate with a mating surface of the filter element sleeve 1506 to transmit rotation from the drive shaft 1504 to the filter element 1502 (e.g., as shown in Fig. 19 and Fig. 20). In alternative arrangements, the drive portion 1702 of the drive shaft 1504 may include any combination of drive surfaces (e.g., flat or angled surfaces), protrusions, and / or keyways that cooperate with the filter element sleeve 1506 to transmit rotation from the drive shaft 1504 to the filter element 1502.

[0025] The filter element sleeve 1506 is sized and shaped to receive the drive shaft 1504. As best shown in Fig. 18, the filter element sleeve 1506 includes a plurality of protrusions 1802 on an inner surface of the filter element sleeve 1506. The plurality of protrusions 1802 comprise radially inwardly projecting ridges that cooperate with the flat surfaces of the drive portion 1702 of the drive shaft 1504 to transmit rotation from the drive shaft 1504 to the filter element 1502 (e.g., as shown in Fig. 19 and Fig. 20). In some arrangements, there are six equally sized and evenly spaced projections 1802 (e.g., as shown in Fig. 18) that form a hexalobular keyway 1804 to receive the drive shaft 1504. In alternative arrangements, the filter element sleeve 1506 may include any combination of drive surfaces (e.g., flat or angled surfaces), protrusions, and / or keyways that cooperate with the drive shaft 1504 to transmit rotation from the drive shaft 1504 to the filter element 1502.

[0026] As in Fig. 19, Fig. 20 and Fig. As shown in Figure 21, when the filter element 1502 is installed over the drive shaft 1504, the drive shaft 1504 is received within the filter element sleeve 1506. The flat surfaces of the drive portion 1702 cooperate with the projections 1802 to provide a drive interface between the drive shaft 1504 and the filter element sleeve 1506. The projections 1802 provide raised planar surfaces that make surface contact (as opposed to point or line contact) with the flat surfaces of the drive portion 1702 of the drive shaft 1504 when the drive shaft 1504 applies torque to the filter element 1502. Accordingly, when the drive shaft 1504 rotates in the direction of arrow 1902, the filter element 1502 also rotates in the direction of arrow 1902. In addition, since the drive shaft 1504 and the filter element sleeve 1506 are symmetrical, the drive shaft 1504 and the filter element 1502 can rotate in any direction (ieclockwise or counterclockwise) without sacrificing contact area of ​​the drive surface. As shown in . Fig. 21, in some arrangements or rotational orientations of the filter element 1502, there is a gap between the flat surfaces of the drive portion 1702 and the mating flat drive surfaces of the projections 1802. These surfaces (i.e., the flat surfaces of the drive portion 1702 and the mating flat drive surfaces of the projections 1802) can only be in contact if they are parallel when the drive shaft 1504 rotates to the flat surface of the projection 1802.

[0027] In some arrangements, the drive portion 1702 of the drive shaft 1504 includes rounded or beveled edges 2102 connecting adjacent flat surfaces, providing a relief or gap to the root radius of the projections 1802. In some arrangements, the filter element sleeve 1506 includes relief portions 2104 disposed between adjacent projections 1802. The relief portions 2104 also provide a radius at an inside corner of the projections 1802, reducing mechanical stress on the projections 1802 during operation. The rounded or beveled edges 2102 and the relief portions 2104 are in Fig. 21 in more detail. As best seen in Fig. 15, the sleeve projections 1802 do not extend over the entire axial length of the filter element sleeve 1506 to allow an axial portion of the drive shaft 1504, which is not flattened, to cooperate with an upper portion of the filter element sleeve 1506 (e.g., as shown in Fig. 16) to limit axial movement of the filter element 1502 relative to the drive shaft 1504. The axial portion of the drive shaft 1504, which is not flattened to engage the upper portion of the filter element sleeve 1506, improves radial stability due to the narrow gap between the drive shaft 1504 and the filter element sleeve 1506, which reduces vibration and excessive wear or the risk of functional failure of the filter element sleeve 1506 and / or the drive shaft 1504. In some arrangements, the filter element sleeve 1506 is a two-sleeve design (e.g., as best shown in Fig. 15) that includes a drive portion 1508 having the plurality of projections 1802 and a raceway or bushing portion 1510 that is a precise cylindrical surface. In such arrangements, the two-sleeve designs can improve the manufacturability of the filter element sleeve 1506. In addition, the relief portion 2104 in the filter element sleeve 1506 and the recesses where the drive shaft 1504 meets the round part of the filter element sleeve 1506 (i.e., the base of the filter element sleeve 1506) form "debris pockets" when viewed from the top of the filter element 1502. These dirt pockets can collect dirt particles, thereby preventing migration of wear particles, for example, dirt particles originating from the coil spring 1304 above the element (e.g., in a similar manner as described above with respect to Fig. 13 and Fig.14). In other arrangements, the filter element sleeve 1506 includes relief portions 2104, while the drive shaft 1504 does not include chamfers 2102. In such arrangements, there is a gap between the drive shaft 1504 and the filter element sleeve 1506 during installation of the filter element 1502 and no gap when the drive shaft 1504 rotates into the flat portion of the boss 1802 during operation.

[0028] The rotating filter elements and drive systems described above can be used in a variety of systems. For example, the rotating filter elements and drive systems described above can be used in crankcase ventilation systems to separate oil and aerosol from crankcase bypass gases. Furthermore, the rotating filter elements and drive systems described above can be used in natural gas filtration to remove oil and aerosol from natural gas. The examples mentioned are not intended to be limiting, as the rotating filter elements and drive systems can be used in any suitable filtration system.

[0029] It should be noted that the term "exemplary" used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and / or illustrations of possible embodiments (and that such a term is not necessarily intended to imply that such embodiments are exceptional or excellent examples).

[0030] As used herein, the term "connected" and similar terms means the direct or indirect connection of two elements to one another. This connection can be stationary (e.g., permanent) or movable (e.g., removable or detachable). This connection can be achieved by the two elements, or the two elements and any other intermediate elements, being integrally formed as a unitary body, or by the two elements, or the two elements and any other intermediate elements, being fastened to one another.

[0031] References herein to the positions of elements (e.g., "upper," "lower," "above," "below," etc.) merely describe the orientation of the various elements in the figures. It should be noted that the orientation of various elements may vary depending on other exemplary embodiments, and the present disclosure encompasses such variations.

[0032] It should be understood that the construction and arrangement of the various exemplary embodiments are for illustrative purposes only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art will readily appreciate upon reading this disclosure that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and portions of the various elements, values ​​of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as being integrally formed may be constructed from multiple parts or elements, the position of the elements may be reversed or otherwise varied, and the nature or number of separate elements or positions may be changed or varied.The order or sequence of method or process steps may be varied or rearranged according to alternative embodiments. Furthermore, features from certain embodiments may be combined with features from other embodiments, as will be apparent to those skilled in the art. Other substitutions, modifications, changes, and omissions may also be made to the construction, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of the present invention. 102 filter element 104 Drive shaft 106 filter medium 108 first end cap 110 second end cap 112 filter element sleeve 114 Electric motor 116 Arrow 117 O-ring 302 flat section 404 sleeve projection 602 Arrow 604 Bevel 606 Relief section 1102 warehouses 1104 Cover 1106 Housing 1302 arrows 1304 spiral spring 1500 filtration system 1502 filter element 1504 drive shaft 1506 filter element sleeve 1508 drive section 1510 Barrel sleeve section or bushing section 1702 drive section 1802 projections 1804 hexagon socket keyway 2102 rounded or bevelled edges 2104 relief sections

Claims

[1] Rotating filter element (102, 1502) comprising: a first end plate (108), a second end plate (110), a filter medium (106) disposed between the first end plate (108) and the second end plate (110), and a filter element sleeve or bushing (112, 1506) configured to receive a drive shaft (104, 1504) of a filtration system when the rotating filter element (102, 1502) is installed in the filtration system, wherein the filter element sleeve or bushing (112, 1506) has a projection (404) projecting radially inward, wherein the filter element sleeve or bushing (112, 1506) includes a relief portion (606) providing a radius at an inside corner of the projection (404), wherein the projection (404) cooperates with the drive shaft (104, 1504) of the filtration system to transmit rotation from the drive shaft (104, 1504) to the rotating filter element (102, 1502), wherein the rotating filter element (102, 1502) is arranged to separate a suspended liquid from a fluid. [2] The rotating filter element (102, 1502) of claim 1, wherein the projection (404) comprises a raised planar surface that makes surface contact with a flat portion (302) of the drive shaft (104, 1504) during rotation of the drive shaft (104, 1504). [3] The rotating filter element (102, 1502) of claim 1, wherein the rotating filter element is a rotating coalescer. [4] The rotating filter element (102, 1502) of claim 3, wherein the fluid comprises crankcase leak gases and the suspended liquid comprises oil or aerosol. [5] The rotating filter element (102, 1502) of claim 1, wherein the filter element sleeve or bushing (112, 1506) includes a plurality of projections (1802) surrounding the projection (404), the plurality of projections (1802) forming a hexalobular keyway (1804) that receives a drive portion (1702) of the drive shaft (104, 1504). [6] The rotating filter element (102, 1502) of claim 5, wherein the filter element sleeve or bushing (112, 1506) includes a relief portion (2104) disposed between each adjacent projection (1802) of the plurality of projections (1802). [7] Filtration system with a rotating filter element (102, 1502) according to one of claims 1 to 6, comprising: a housing (1106) having an inlet and an outlet; a drive mechanism comprising a drive shaft (104, 1504) having a flat portion (302); the rotating filter element (102, 1502) of any one of claims 1 to 6 disposed within the housing and in fluid communication with the inlet and the outlet, the rotating filter element being configured to separate the suspended liquid from a fluid received through the inlet. [8] The filtration system of claim 7, wherein the drive shaft (104, 1504) includes a chamfer (604) adjacent the flat portion (302). [9] The filtration system of claim 7, further comprising an O-ring (117) disposed in a narrowed portion (702) of the drive shaft (104, 1504). [10] The filtration system of claim 7, wherein the fluid received through the inlet is crankcase blow-by gas of an internal combustion engine and wherein the suspended liquid comprises oil or aerosol. [11] The filtration system of claim 7, further comprising a snap ring disposed in a narrowed portion (702) of the drive shaft (104, 1504). [12] The filtration system of claim 7, wherein the drive shaft (104, 1504) includes a plurality of flat portions encompassing the flat portion (302), the plurality of flat portions forming a hexagonal cross-sectional shape at a drive portion (1702) of the drive shaft (104, 1504). [13] The filtration system of claim 12, wherein the drive shaft (104, 1504) includes a plurality of bevels (2102) connecting adjacent flat portions of the plurality of flat portions. [14] The filtration system of claim 7, wherein the drive shaft (104, 1504) comprises at least one of a flat portion (302), a projection (1802), or a keyway (1804) on a drive portion (1702) of the drive shaft (104, 1504). [15] The filtration system of claim 14, wherein the filter element sleeve or bushing (112, 1506) includes a keyway (1804) that receives the drive portion (1702) of the drive shaft (104, 1504).

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