Air coarse strainer

Abstract

An air strainer for centrifugally separating contaminants from a flow of air, the strainer having one or more of: each fin overlapping an immediately adjacent fin by at least 30%; the streamlined inlet surface appears above a distance of at least 8 mm into the annular air intake passage; each fin inclines backwards and deviates from the radial direction by at least 30 degrees; the at least two exhaust ports are oriented non-perpendicular to the long axis of the outer housing; the paddle assembly includes a rotatable portion of an inner member of the air strainer; and the number of connecting arms in the paddle assembly is at least one less than the number of the discharge paddles.

Description

Technical Field

[0001] The present invention relates to engine intake air treatment and, more particularly, to a pre-air cleaner assembly for removing contaminants from intake air. Background Art

[0002] It is known in the art of engine design and operation that contaminants may negatively impact engine operation and shorten useful life. Since ambient air is known to contain such contaminants, one major potential source of contaminants is the air drawn into the engine for fuel combustion.

[0003] In order to prevent or at least reduce the entry of contaminants into the engine via the engine air supply, various forms of air filtration have been proposed and widely implemented. One such technology is an air prefilter, which incorporates fins in a well-known manner to centrifugally separate contaminants from the air flow, which contaminants can be retained within a section of the prefilter for later removal or ejection from the prefilter.

[0004] However, prefilter design is challenging in that it must balance pollutant removal efficiency with the desire to reduce airflow resistance because designs that favor reduced resistance often result in poor pollutant extraction, while designs with high pollutant extraction rates often involve higher airflow resistance that has negative repercussions on engine operation.

[0005] Further limitations of existing strainer designs have been noted, such as ejected contaminants being drawn back into the incoming air stream, or air stream turbulence at the inlet negatively impacting strainer operation. Summary of the invention

[0006] According to a first broad aspect of the present invention, there is provided an air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising:

[0007] External housing;

[0008] an internal member disposed within the outer housing and coaxial with the outer housing;

[0009] The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants;

[0010] a plurality of static fins disposed within an upstream portion of the annular air intake passage, wherein each of the plurality of static fins overlaps an immediately adjacent fin of the plurality of static fins by at least 30%, the plurality of static fins being configured to impart a rotational direction to the pollutant laden air flow and to centrifugally separate at least some pollutants from the pollutant laden air flow to form a pollutant concentrated exhaust flow and a clean air flow, the internal component being configured to receive the clean air flow and to deliver the clean air flow out of the pre-air cleaner; and

[0011] At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

[0012] In some exemplary embodiments of the first aspect, each of the plurality of static fins overlaps an immediately adjacent fin of the plurality of static fins by between 30% and 90%.

[0013] According to a second broad aspect of the invention, there is provided an air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising:

[0014] an outer shell including a streamlined inlet surface transitioning to an inner surface of the outer shell;

[0015] an internal member disposed within the outer housing and coaxial with the outer housing;

[0016] an inner surface of the outer shell and an outer surface of the inner member, the inner surface of the outer shell and the outer surface of the inner member defining an annular air inlet passage therebetween, the annular air inlet passage for receiving a pollutant-laden air flow, the pollutant-laden air flow including pollutants, the transition of the streamlined inlet surface occurring over a distance of at least 8 mm into the annular air inlet passage;

[0017] a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant laden air flow and to centrifugally separate at least some pollutants from the pollutant laden air flow to form a pollutant concentrated exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and deliver the clean air flow out of the pre-air cleaner; and

[0018] At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

[0019] In some exemplary embodiments of the second aspect, the streamlined inlet surface has an elliptical profile. In other exemplary embodiments, the streamlined inlet surface has a flared profile. In some exemplary embodiments, the transition of the streamlined inlet surface is uninterrupted.

[0020] According to a third broad aspect of the invention, there is provided an air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising:

[0021] External housing;

[0022] an internal member disposed within the outer housing and coaxial with the outer housing;

[0023] The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants;

[0024] a plurality of static fins disposed within an upstream portion of the annular air inlet passage and extending between an inner surface of the outer shell and an outer surface of the inner member, each of the plurality of fins being tilted rearwardly at least 30 degrees from a radial direction, the plurality of static fins being configured to impart a rotational direction to the pollutant-laden air flow and to centrifugally separate at least some pollutants from the pollutant-laden air flow to form a pollutant-concentrated exhaust flow and a clean air flow, the inner member being configured to receive the clean air flow and deliver the clean air flow out of the pre-air filter; and

[0025] At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

[0026] In some exemplary embodiments of the third aspect, each of the plurality of fins is at least partially curved and rearwardly inclined adjacent to an outer surface of the inner member. In some exemplary embodiments, each of the plurality of fins is approximately radially oriented adjacent to an inner surface of the outer shell.

[0027] According to a fourth broad aspect of the present invention, there is provided an air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising:

[0028] External housing;

[0029] an internal member disposed within the outer housing and coaxial with the outer housing;

[0030] The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants;

[0031] a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant laden air flow and to centrifugally separate at least some pollutants from the pollutant laden air flow to form a pollutant concentrated exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and deliver the clean air flow out of the pre-air cleaner; and

[0032] At least two exhaust ports in the outer housing allow the pollutant-laden exhaust flow to pass through and exit the pre-air filter, the at least two exhaust ports being oriented non-perpendicular to a long axis of the outer housing.

[0033] In some exemplary embodiments of the fourth aspect, each of the at least two exhaust ports is angled non-parallel to a major axis of the outer housing. In some exemplary embodiments, each of the at least two exhaust ports is defined by a pair of peripheral surfaces that are streamlined to non-tangentially direct the pollutant-concentrated exhaust flow outwardly away from the pre-air filter.

[0034] According to a fifth broad aspect of the present invention, there is provided an air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising:

[0035] External housing;

[0036] an internal member disposed within the outer housing and coaxial with the outer housing;

[0037] The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants;

[0038] a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant laden air flow and to centrifugally separate at least some pollutants from the pollutant laden air flow to form a pollutant concentrated exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and to deliver the clean air flow out of the pre-air filter;

[0039] A paddle assembly, the paddle assembly comprising:

[0040] a rotatable member configured to rotate in response to flow of a clean air stream past the rotatable member;

[0041] at least one peripheral member holding one or more discharge paddles in a downstream portion of the annular air inlet passage for directing the pollutant-laden exhaust gas flow outwardly toward the inner surface of the outer shell; and

[0042] at least one connecting arm extending radially outward from the rotatable member to the at least one peripheral member;

[0043] wherein the number of connecting arms is at least one less than the number of discharge paddles; and

[0044] At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

[0045] In some exemplary embodiments, the rotatable member includes a rotatable portion of the inner member and at least one rotor drive paddle connected to and at least partially retained within the rotatable portion, and wherein the at least one rotor drive paddle includes at least one angled portion to assist rotation of the at least one rotor drive paddle in response to the flow of the clean air stream. The at least one peripheral member can be a single paddle ring that holds all of the discharge paddles; alternatively, the at least one peripheral member can be at least two peripheral members, at least one of the at least two peripheral members holding at least two of the discharge paddles. Some exemplary embodiments include at least five rotor drive paddles.

[0046] According to a sixth broad aspect of the present invention, there is provided an air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising:

[0047] External housing;

[0048] an internal member disposed within the outer housing and coaxial with the outer housing;

[0049] The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants;

[0050] a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant laden air flow and to centrifugally separate at least some pollutants from the pollutant laden air flow to form a pollutant concentrated exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and to deliver the clean air flow out of the pre-air filter;

[0051] A paddle assembly, the paddle assembly comprising:

[0052] a rotatable portion of the inner member, the rotatable portion configured to rotate in response to flow of the clean air stream past the rotatable member;

[0053] at least one discharge paddle retained in a downstream portion of the annular air inlet passage for directing the pollutant-laden exhaust gas flow outwardly toward the inner surface of the outer housing; and

[0054] at least one connecting arm extending radially outward from the rotatable portion to the at least one discharge paddle; and

[0055] At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

[0056] Some exemplary embodiments of the sixth broad aspect further include at least one rotor drive propeller connected to the rotatable portion and at least partially retained within the rotatable portion, and wherein the at least one rotor drive propeller includes at least one angled portion to assist rotation of the at least one rotor drive propeller in response to the flow of the clean air flow.

[0057] In some exemplary embodiments, the number of rotor drive paddles is at least one less than the number of connecting arms.

[0058] In some exemplary embodiments, the at least one discharge paddle is retained on a peripheral member connected to the at least one connecting arm.

[0059] A detailed description of exemplary embodiments of the present invention is given below. However, it should be understood that the present invention should not be construed as being limited to these embodiments. The exemplary embodiments are directed to specific applications of the present invention, and it will be clear to those skilled in the art that the present invention has applicability beyond the exemplary embodiments described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In the accompanying drawings, exemplary embodiments according to the present invention are shown:

[0061] Figure 1 is a bottom perspective view of an exemplary embodiment of the present invention.

[0062] Figure 2a yes Figure 1 A bottom plan view of an exemplary embodiment of the invention.

[0063] Figure 2b is a top plan view of an exemplary fin assembly showing the rearward tilt angle of the fins.

[0064] Figure 3 is an inverted bottom perspective view of an exemplary embodiment of the present invention.

[0065] Figure 4 yes Figure 3 A side perspective view of an exemplary embodiment of the invention is shown partially transparent to illustrate overlapping fins.

[0066] Figure 5 It is an inverted bottom perspective view showing a contoured inlet.

[0067] Figure 6 is a diagram showing one example of a streamlined inlet cross section with exemplary measurements.

[0068] Figure 7 is a cross-sectional view of an exemplary embodiment through the center on a plane parallel to the major axis.

[0069] Figure 8 is a detailed bottom perspective view showing the overlapping rings tilted backwards.

[0070] Fig. 9 is a side elevation view showing an exemplary embodiment of an exhaust port in an outer housing.

[0071] Fig.10 is a top perspective view showing the exhaust port in the outer housing. Fig.11 is a side elevation view showing the exhaust port in the outer housing.

[0072] Fig.12 is a detailed cross-sectional view through the exhaust port showing the streamlined profile of the exhaust port.

[0073] Fig.13 is a top perspective view of an exemplary paddle assembly.

[0074] Fig.14 are cross-sectional and detail views of an exemplary paddle assembly in a plane perpendicular to the major axis.

[0075] Fig.15 is a top perspective view of an exemplary embodiment with the top portion transparent to illustrate an exemplary paddle assembly.

[0076] Fig.16is an exploded view of an exemplary embodiment.

[0077] Fig.17a , Fig.17b and Fig.17c are top perspective, side perspective, and plan views of another exemplary paddle assembly.

[0078] Exemplary embodiments will now be described with reference to the accompanying drawings. DETAILED DESCRIPTION

[0079] Throughout the following description, specific details are set forth to provide a more thorough understanding for those skilled in the art. However, well-known elements may not be shown or described in detail to avoid unnecessarily obscuring the present disclosure. The following description of examples of the present invention is not intended to be exhaustive or to limit the present invention to the exact form of any exemplary embodiment. Therefore, the description and drawings should be regarded as illustrative rather than restrictive.

[0080] The present invention relates to an air coarse filter for centrifugally removing pollutants from intake air to allow a cleaner air flow to enter, for example, an engine air intake. Embodiments according to the present invention may combine one or more of the following: each fin overlaps the immediately adjacent fin by at least 30%; the streamlined inlet surface appears over a distance of at least 8 mm into the annular air intake passage; each of the fins is tilted rearwardly at least 30 degrees from the radial direction; at least two exhaust ports are oriented non-perpendicular to the long axis of the outer shell; the paddle assembly comprises a rotatable portion of the internal component of the air coarse filter; and the number of connecting arms in the paddle assembly is at least one less than the number of exhaust paddles.

[0081] Now go to Figure 1 2, an exemplary air pre-cleaner 10 is shown. The pre-cleaner 10 includes an outer housing 12 and an inner member 14 coaxially disposed within the outer housing 12, thereby forming an annular air intake passage 20 between an inner surface 16 of the outer housing 12 and an outer surface 18 of the inner member 14. Figure 7 As best seen in FIG. 2 , the annular air intake passage 20 extends toward the top plate 70 and then communicates with the interior of the hollow cylindrical inner member 14. A pollutant-laden air stream 24 is drawn into the passage 20, and the pollutants are removed as described below, thereby producing a pollutant-concentrated exhaust stream 26 and a clean air stream 28. The clean air stream 28 is intended to be introduced into, for example, an engine. The inner member 14 includes a notch 56 and a clamp 58 at the outlet end to allow the inner member 14 to be secured to, for example, the air intake of an engine. A structural support member 60 inside the inner member 14 is shown in FIG. 2 .

[0082] The strainer 10 further includes a plurality of radially disposed fins 22 extending between the inner surface 16 and the outer surface 18. The fins 22 are fixed, and they may be straight or (as shown) curved. The function of the fins 22 is to receive a pollutant-laden air stream 24 and impart a rotation to the stream 24 so that the pollutants in the air stream 24 are forced outwardly by centrifugal force toward a plurality of exhaust ports 30 in the outer housing 12, through which an exhaust stream 26 containing pollutants is discharged.

[0083] Figures 2a to 4 Various features of exemplary fins 22 are shown, not all of which are present in every exemplary embodiment of the invention. Some exemplary fins are tilted backwards at least 30 degrees from the radial direction. In some exemplary embodiments, such as Figure 2a and 2b As shown in FIG. 1 , the fins 22 are angled rearwardly about 60 degrees from the radial direction. It has been found that the rearwardly angled fin design can improve contaminant removal while maintaining a desired level of air resistance, and it is believed (without being bound by theory) that this design helps to force contaminants outwardly toward the outer housing.

[0084] In some further embodiments, the rearwardly inclined fins (such as the fins 22 of the illustrated embodiment) may be further curved so that the fins are rearwardly inclined at the inner member but transition toward vertical at the outer shell, such as Figure 8 Again without being limited by theory, it is believed that the transition to verticality can reduce air drag.

[0085] Figure 4 An exemplary embodiment is shown in which each fin 22 overlaps the immediately adjacent fin 22, and the immediately adjacent fin is itself overlapped by the fin 22 on the other side thereof. The degree of overlap is at least 30%, and it has been found that fin overlap of at least 30% increases separation performance while reducing air drag. Below is a graph showing the effect of fin overlap on separation efficiency and air drag.

[0086] Fin overlap (efficiency)

[0087]

[0088] Fin overlap (air resistance)

[0089]

[0090] The exemplary strainer 10 further includes a streamlined inlet surface 32 at an inlet end 34 of the outer housing 12 . Figure 1 Figure 2 Figure 3 and Figure 5 This streamlined inlet surface 32 is shown from different angles, and Figure 6Exemplary measurements of such a streamlined inlet surface 32 are provided (in mm and degrees). It has been found that the air inlet of the prior art coarse filter assembly is typically non-streamlined (flat end with straight walls) or has some structural interruption to the surface which has been found to introduce turbulence into the incoming air flow, thereby undesirably increasing air resistance. It has been found that incorporating a streamlined inlet surface that appears over a distance of at least 8 mm extending from the inlet end 34 into the annular air intake passage 20 can provide a smoother intake air flow that can reduce turbulence, thereby providing improved air resistance. The following is a graph showing the effect of streamlines on air resistance.

[0091] Inlet surface

[0092]

[0093] As noted above, the purpose of a prefilter is to remove contaminants to enable a cleaner air flow to be provided, for example, to an engine intake, and to this end, certain prefilter assemblies, such as embodiments of the present invention, generate centrifugal forces to move contaminants outwardly toward one or more exhaust ports in an outer housing. Figures 9 to 12 , shows an exemplary embodiment of the present invention, wherein a plurality of exhaust ports 30 are provided in the outer housing 12 to allow exhaust of the pollutant-rich exhaust stream 26. Fig. 9 As can be best seen in FIG. 1 , the exhaust ports 30 are oriented non-perpendicular to the long axis of the outer housing 12, and specifically in the illustrated embodiment, these exhaust ports are disposed on the circumferential side of the outer housing 12 in an angled orientation. Other arrangements and orientations of the exhaust ports are possible within the scope of the present invention. In addition to potentially improving separation efficiency and air drag, it has also been found that the angled exhaust ports 30 can desirably reduce exhaust noise. Below is a graph illustrating the effect of the exhaust port angle on exhaust noise.

[0094] Exhaust port angle

[0095]

[0096] One drawback noted in some prior art designs is the re-intake of exhaust gas, as some designs exhaust the exhaust gas tangentially to the port and are therefore not very effective in forcing the exhaust gas far enough away from the intake area. In some embodiments of the present invention, this drawback is addressed by streamlining the exhaust port 30, such as Fig.12 As can be seen, each exhaust port 30 includes a pair of peripheral surfaces 36 that effectively redirect the pollutant-rich exhaust gas flow 26 outwardly away from the strainer 10. While any angle greater than tangential may be beneficial, the illustrated embodiment shows a direction 38 that is nearly radial and therefore most desirable.

[0097] Now go to Figures 13 to 16 , shows an exemplary paddle assembly 40 for a coarse filter 10. The discharge paddle 46 rotates within the outer housing 12 to help push pollutants toward the exhaust port 30. In prior art designs, each discharge paddle is connected to a central hub by a connecting arm, so as the number of discharge paddles increases, the number of connecting arms passing through the airflow passage must increase, which undesirably increases air resistance and increases turbulence. To address this shortcoming, certain embodiments of the present invention employ one or more peripheral members, and in the illustrated embodiment, a single paddle ring 44 is employed to support the discharge paddles 46. By having at least one peripheral member support two or more discharge paddles, fewer connecting arms are required. As can be seen in the illustrated embodiment, for example, the use of a single paddle ring 44 to support all fifteen discharge paddles 46 allows the use of only five connecting arms 48, thereby significantly reducing the amount of structure passing through the air passage.

[0098] The paddle assembly 40 further includes a means for imparting rotation to the discharge paddle 46 via the connecting arm 48 and the paddle ring 44, namely a rotatable member 42. Fig.13 As best seen in FIG. 1 , the rotatable member 42 is centrally disposed within the strainer 10 and includes a rotatable portion 50 of the inner member 14 and a plurality of rotor drive paddles 52. The rotor drive paddles 52 are rotatably mounted on a shaft 72 (at Figure 7 and Fig.16 4 (shown in FIG. 4 ), wherein the flow of clean air stream 28 engages paddle 52, thereby causing rotation of rotatable member 42. Rotor driven paddle 52 includes angled portion 54 to better capture the energy of stream 28, thereby moving paddle ring 44 and discharge paddle 46. Rotor driven paddle 52 is mounted on rotatable portion 50 of internal member 14, and the rotation of rotor driven paddle 52 drives the rotation of rotatable portion 50 (independent of the rest of the stationary portion of internal member 14). Connecting arm 48 is mounted on rotatable portion 50 and thus rotates as rotatable portion 50 rotates, thereby imparting rotation to paddle ring 44, which causes discharge paddle 46 to move around the periphery of the internal passage adjacent exhaust port 30 and help to discharge exhaust stream 26 where pollutants are concentrated.

[0099] although Fig.13 The embodiment shown in has the same number of rotor drive blades 52 and connecting arms 48, but having a different number is also within the scope of the present invention. Figures 17a to 17cAs shown, the rotor driven paddles may be less than the connecting member, and the paddle ring is omitted in this embodiment. In this illustrated embodiment, the paddle assembly 80 includes a device, namely a rotatable member 82, which imparts rotation to the discharge paddle 86 via a connecting arm 88. The rotatable member 82 is centrally disposed within the coarse filter and includes a rotatable portion 90 of the internal member and a plurality of rotor driven paddles 92. The flow of the clean air stream engages the rotor driven paddles 92, thereby causing the rotation of the rotatable member 82. The rotor driven paddles 92 include angled portions 94 to better capture the energy of the flow, thereby moving the discharge paddle 86. The rotor driven paddles 92 are mounted on the rotatable portion 90 of the internal member, and the rotation of the rotor driven paddles 92 drives the rotation of the rotatable portion 90 (independent of the stationary rest of the internal member). The connecting arm 88 is mounted on the rotatable portion 90 and therefore rotates as the rotatable portion 90 rotates, thereby imparting rotation to the discharge paddle 86 to move around the periphery of the internal passage adjacent to the exhaust port and help discharge the exhaust stream where pollutants are concentrated. In this embodiment, there are only six rotor drive paddles 92, while there are twelve connecting arms 88, each connected to a discharge paddle 86. As will be clear based on the teachings herein, the discharge paddle 86 may also be retained on the paddle ring to which the connecting arms 88 are connected, so the number of rotor drive paddles 92, connecting arms 88, and discharge paddles 86 may be different from each other.

[0100] Fig.15 With partial transparency view and Fig.16 Certain structural details of the exemplary strainer 10 are shown in exploded view. For example, it can be seen that the outer housing 10 includes a cover 62, a top plate 70, an upstream fin assembly 64, a downstream fin assembly 66, and an exhaust section 68. The exhaust section 68 (also shown in FIG. Figure 7 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 and Fig.14 ) is a separator mounted in a spaced apart orientation such that the spaces between the segments 68 are exhaust ports 30 .

[0101] The foregoing is considered to be illustrative only of the principles of the present invention. The scope of the claims should not be limited by the exemplary embodiments set forth above, but should be given the broadest interpretation consistent with the entire specification.

Claims

1. An air filter for centrifugally separating pollutants from an air flow introduced into the air filter, the air filter comprising: External housing; an internal member disposed within the outer housing and coaxial with the outer housing; The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants; a plurality of static fins disposed within an upstream portion of the annular air intake passage, wherein each of the plurality of static fins overlaps an immediately adjacent fin of the plurality of static fins by at least 30%, the plurality of static fins being configured to impart a rotational direction to the pollutant laden air stream and to centrifugally separate at least some pollutants from the pollutant laden air stream to form a pollutant concentrated exhaust stream and a clean air stream, the internal component being configured to receive the clean air stream and deliver the clean air stream out of the pre-air cleaner; as well as At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

2. The air pre-filter according to claim 1, wherein: Each of the plurality of static fins overlaps an immediately adjacent fin of the plurality of static fins by between 30% and 90%.

3. An air filter for centrifugally separating pollutants from an air flow introduced into the air filter, the air filter comprising: an outer shell including a streamlined inlet surface transitioning to an inner surface of the outer shell; an internal member disposed within the outer housing and coaxial with the outer housing; an inner surface of the outer shell and an outer surface of the inner member, the inner surface of the outer shell and the outer surface of the inner member defining an annular air inlet passage therebetween, the annular air inlet passage for receiving a pollutant-laden air flow, the pollutant-laden air flow including pollutants, the transition of the streamlined inlet surface occurring over a distance of at least 8 mm into the annular air inlet passage; a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant-laden air flow and to centrifugally separate at least some pollutants from the pollutant-laden air flow to form a pollutant-focused exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and deliver the clean air flow out of the pre-air cleaner; as well as At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

4. The air pre-filter according to claim 3, wherein: The streamlined inlet surface has an elliptical profile.

5. The air pre-filter according to claim 3, wherein: The streamlined inlet surface has a flared profile.

6. The air pre-cleaner according to claim 3, wherein: The transition to the streamlined inlet surface is uninterrupted.

7. An air filter for centrifugally separating pollutants from an air flow introduced into the air filter, the air filter comprising: External housing; an internal member disposed within the outer housing and coaxial with the outer housing; The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants; a plurality of static fins disposed within an upstream portion of the annular air inlet passage and extending between an inner surface of the outer shell and an outer surface of the inner member, each of the plurality of fins being tilted rearwardly at least 30 degrees from a radial direction, the plurality of static fins being configured to impart a rotational direction to the pollutant-laden air flow and to centrifugally separate at least some pollutants from the pollutant-laden air flow to form a pollutant-concentrated exhaust flow and a clean air flow, the inner member being configured to receive the clean air flow and deliver the clean air flow out of the pre-air filter; as well as At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

8. The air pre-cleaner according to claim 7, wherein: Each fin of the plurality of fins is at least partially curved adjacent the outer surface of the inner member and slopes rearwardly.

9. The air pre-cleaner according to claim 8, wherein: Each fin of the plurality of fins is oriented approximately radially adjacent the inner surface of the outer shell.

10. An air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising: External housing; an internal member disposed within the outer housing and coaxial with the outer housing; The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants; a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant-laden air flow and to centrifugally separate at least some pollutants from the pollutant-laden air flow to form a pollutant-focused exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and deliver the clean air flow out of the pre-air cleaner; as well as At least two exhaust ports in the outer housing allow the pollutant-laden exhaust flow to pass through and exit the pre-air filter, the at least two exhaust ports being oriented non-perpendicular to a long axis of the outer housing.

11. The air pre-cleaner according to claim 10, wherein: Each of the at least two exhaust ports is angled non-parallel to a major axis of the outer housing.

12. The air pre-cleaner according to claim 10, wherein: Each of the at least two exhaust ports is defined by a pair of peripheral surfaces that are streamlined to non-tangentially direct the pollutant-rich exhaust flow outwardly away from the pre-air filter.

13. An air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising: External housing; an internal member disposed within the outer housing and coaxial with the outer housing; The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants; a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant-laden air flow and to centrifugally separate at least some pollutants from the pollutant-laden air flow to form a pollutant-focused exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and deliver the clean air flow out of the pre-air cleaner; A paddle assembly, the paddle assembly comprising: a rotatable member configured to rotate in response to flow of the clean air stream past the rotatable member; at least one peripheral member holding one or more discharge paddles in a downstream portion of the annular air inlet passage for directing the pollutant-laden exhaust gas flow outwardly toward the inner surface of the outer shell; and at least one connecting arm extending radially outward from the rotatable member to the at least one peripheral member; wherein the number of the connecting arms is at least one less than the number of the discharge paddles; and At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

14. The air pre-cleaner according to claim 13, wherein: The rotatable member includes a rotatable portion of the inner member and at least one rotor drive paddle connected to and at least partially retained within the rotatable portion, and wherein the at least one rotor drive paddle includes at least one angled portion to assist rotation of the at least one rotor drive paddle in response to the flow of the clean air stream.

15. The air pre-cleaner according to claim 13, wherein: The at least one peripheral member is a single paddle ring that holds all of the discharge paddles.

16. The air pre-cleaner of claim 13, wherein: The at least one peripheral member is at least two peripheral members, at least one of the at least two peripheral members holding at least two of the discharge paddles.

17. The pre-air cleaner of claim 14, comprising at least five rotor driven paddles.

18. An air prefilter for centrifugally separating pollutants from an air flow introduced into the air prefilter, the air prefilter comprising: External housing; an internal member disposed within the outer housing and coaxial with the outer housing; The inner surface of the outer shell and the outer surface of the inner component define an annular air intake passage between the inner surface of the outer shell and the outer surface of the inner component, the annular air intake passage is used to receive the pollutant-laden air flow, the pollutant-laden air flow includes pollutants; a plurality of static fins disposed within an upstream portion of the annular air intake passage, the plurality of static fins configured to impart a rotational direction to the pollutant-laden air flow and to centrifugally separate at least some pollutants from the pollutant-laden air flow to form a pollutant-focused exhaust flow and a clean air flow, the internal component configured to receive the clean air flow and deliver the clean air flow out of the pre-air cleaner; A paddle assembly, the paddle assembly comprising: a rotatable portion of the inner member, the rotatable portion configured to rotate in response to flow of the clean air stream past the rotatable member; at least one discharge paddle retained in a downstream portion of the annular air inlet passage for directing the pollutant-laden exhaust gas flow outwardly toward the inner surface of the outer housing; and at least one connecting arm extending radially outwardly from the rotatable portion to the at least one discharge paddle; and At least one exhaust port in the outer housing allows the pollutant-laden exhaust gas flow to pass through and exit the pre-air cleaner.

19. The air precleaner of claim 18, further comprising at least one rotor drive paddle connected to and at least partially retained within the rotatable portion, and wherein: The at least one rotor drive paddle includes at least one angled portion to assist in rotation of the at least one rotor drive paddle in response to the flow of the clean air stream.

20. The pre-air cleaner of claim 19, wherein: The number of the rotor drive paddles is at least one less than the number of the connecting arms.

21. The pre-air cleaner of claim 18, wherein: The at least one discharge paddle is retained on a peripheral member connected to the at least one connecting arm.

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