Inlet design for a pump assembly

One embodiment includes an air pump assembly (10) with an impeller (12), a housing (16), and a diverter (18). The housing (16) surrounds the impeller (12) and has an inlet passage (40) with a longitudinal axis (L) arranged generally non-orthogonally with respect to an axis of rotation of the impeller (12). The diverter (18) helps reduce turbulent flow in the inlet passage (40).

TECHNICAL FIELD

The technical field generally relates to inlet designs for pump assemblies.

BACKGROUND

Pump assemblies having impellers are sometimes designed with an inlet passage that feeds fluid to the impeller. One example of such a pump assembly is a secondary air pump assembly that supplies secondary or intake air to an automotive exhaust system during warm-up of an automotive internal combustion engine, or at other times.

SUMMARY OF ILLUSTRATIVE EMBODIMENTS

One embodiment includes an air pump assembly that may include an impeller, a housing, and a diverter. The impeller may have an axial face and a circumferential periphery. The housing may surround the impeller. The housing may form a part or more of a primary passage for air flow during use of the air pump assembly. The primary passage may be open to the impeller at the axial face of the impeller. The housing may have an inlet passage that may communicate with the primary passage. The inlet passage may have a longitudinal axis that may be arranged generally non-orthogonally with respect to an axis of rotation of the impeller. The diverter may be located partially or more within the inlet passage. The diverter may have a surface that may confront the axial face of the impeller, may confront the circumferential periphery of the impeller, or may confront both the axial face and the circumferential periphery. When the air pump assembly is in use, the diverter may inhibit generation of turbulent flow between incoming air flow and the impeller where the surface confronts the impeller.

One embodiment includes a method. The method may include providing an air pump assembly that may comprise an impeller and a housing. The impeller may have numerous vanes and an axial face. The vanes may have a circumferential periphery. The housing may form a part or more of a primary passage. The primary passage may be open to the vanes at the axial face. The housing may have an inlet passage that may communicate with the primary passage. The inlet passage may have a longitudinal axis that may be arranged generally axially with respect to the impeller. The method may also include diverting a portion or more of incoming air flow through the inlet passage away from the axial face of the impeller, away from the circumferential periphery of the vanes, or away from both the axial face and circumferential periphery.

One embodiment includes an air pump assembly that may include an impeller, a motor, a housing, and a diverter. The impeller may have numerous vanes, a first axial face, and a second axial face. The vanes may have a circumferential periphery. The motor may be connected to the impeller in order to rotate the impeller during use of the air pump assembly. The housing may surround the impeller. The housing may form a part or more of a first primary passage and a part or more of a second primary passage. The first primary passage may be open to the vanes at the first axial face, and the second primary passage may be open to the vanes at the second axial face. The housing may have an inlet passage that may communicate with the first and second primary passages. The inlet passage may have a longitudinal axis that may be arranged generally axially with respect to the impeller. The diverter may have a surface that may confront a portion or more of the axial extent of the circumferential periphery of the vanes via a radial space, may confront a portion or more of the radial extent of the vanes via an axial space, or may confront both the circumferential periphery and the vanes.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following description of the embodiment(s) is merely illustrative in nature and is in no way intended to limit the invention, its application, or its uses.

The figures illustrate several embodiments of an inlet design for a pump assembly that may improve fluid-flow efficiencies in the pump assembly compared to known inlet designs, meaning that the inlet designs disclosed herein may produce greater volumetric flow rate for a given power input. The overall size of the pump assembly may therefore be reduced if suitable and desirable for a particular application, while maintaining the same fluid-flow performance of the larger pump assembly with the known inlet design. Of course, the overall size of the pump assembly with the inlet designs disclosed herein need not be reduced, in which case the pump assembly would simply exhibit improved fluid-flow efficiencies and improved performance. The improvements may result in part from a reduction in turbulence of incoming fluid-flow, as will be described in greater detail below.

Referring toFIG. 1, the inlet designs described herein may be incorporated into a pump assembly10. In the embodiments shown in the figures, the pump assembly10may be a secondary air pump assembly that is used in a secondary air system of an automotive internal combustion engine exhaust system. Secondary air systems are equipped in engine exhaust systems of automotive internal combustion engines in order to supply intake air to the engines during warm-up modes, during other engine modes, or both. Depending upon the particular application, other components of secondary air systems may include an air filter, an air valve, a catalytic converter, a diesel particulate filter, or a combination thereof. Skilled artisans will understand the general construction, arrangement, and operation of these components and others of secondary air systems such that a more detailed description need not be provided here.

The pump assembly10may be of the regenerative pump type. Referring toFIGS. 1-6, in the illustrated embodiment, the pump assembly10may include an impeller12, a motor14, a housing16, and a diverter18.

Referring in particular toFIG. 3where a part of the housing16is removed for demonstrative purposes, the impeller12may be located in the housing and may be rotated by the motor14about an axis of rotation R during use of the pump assembly10. Generally speaking, the impeller12may have a somewhat cylindrical shape that defines directions with respect to the shape including a radial direction, an axial direction, and a circumferential direction; as used herein, and unless otherwise specified, the terms radially, axially, circumferentially, and variants thereof, are in reference to the shape of the impeller. The impeller12may have different designs and constructions, including that shown inFIGS. 3 and 5. In these figures, the impeller12has a body which may have a hub20and numerous vanes22extending radially outwardly from the hub. The hub20may be constructed for connection to a spinning shaft of the motor14. The vanes22may extend circumferentially all-around the hub20, and may each have a terminal end24at a radially-outwardly-most point of the vane. A circumferential periphery26may be an imaginary radially-outwardly-most circumference of the impeller12, and in this embodiment may be defined in part by the terminal ends24of the vanes22. The circumferential periphery26may have an axial height dimension A (FIG. 6) which, in this embodiment, is also the axial height dimension of the vanes22and of the impeller12. Lastly, the impeller12may also have a first axial face28and a second axial face30. The first and second axial faces28,30may be defined by planar surfaces located at opposite axially-outwardly-most ends of the impeller12.

The motor14may be located outside of the housing16and may be mounted to the housing, and may be connected to the impeller12in order to provide rotational drive thereto via its spinning shaft. The motor14is shown schematically inFIG. 5. The motor14may be an electric d.c. motor, or may be another type.

The housing16may provide structural support for components of the pump assembly10. The housing16may have different designs and constructions, including that shown inFIGS. 1-6. In these figures, the housing16may be composed of separate and distinct pieces that are attached together via fasteners, welding, heat staking, or other attachment ways. The pieces may be made of a plastic material, and may be formed by injection molding processes. The housing16may include a body piece32and a cover piece34; in other embodiments, for example, a separate inlet piece could be provided, and a separate outlet piece could also be provided. The body piece32may have a first bulged portion36that partly defines a fluid-flow passage, as discussed below, and likewise the cover piece34may have a second bulged portion38that partly defines a fluid-flow passage.

Furthermore, and as mentioned, the housing16may partly define fluid-flow passages of the pump assembly10. Still referring toFIGS. 1-6, the housing16may have an inlet passage40, an outlet passage42, and a first and second primary passage44,46communicating between the inlet and outlet passages (the first and second primary passages are shown somewhat schematically inFIG. 6for description purposes). In other embodiments not shown in the figures, the housing could have a single primary passage instead of two, and could have two inlet passages such as a housing inlet passage arranged generally radially and a cover inlet passage arranged generally axially as disclosed in United States Patent Application Publication Number 2010/0086396 assigned to this applicant BorgWarner Inc. The inlet passage40may receive incoming fluid-flow and may be defined by an inlet surface48. The inlet passage40may have a generally cylindrical shape, and in one example may have a diameter dimension of approximately 20 mm; other diameter dimensions are possible and may depend on, among other factors, the particular application. In the embodiment ofFIG. 6, the inlet passage40may have a longitudinal axis L that may be arranged generally axially with respect to the impeller12and may be parallel to the axis of rotation R of the impeller. The axial arrangement of the inlet passage40need not be exact axial arrangement with respect to the impeller12, and instead the longitudinal axis L may intersect an imaginary radius of the impeller at an angle that is slightly greater than or less than ninety degrees and is thus generally orthogonal to the imaginary radius. The longitudinal axis L may be arranged non-orthogonally with respect to the axis of rotation R of the impeller12; in other words, the inlet passage40does not direct incoming fluid-flow F radially with respect to the impeller. The inlet passage40may direct incoming fluid-flow F somewhat at the axial face of the impeller12and not directly at the circumferential periphery26. For example, the inlet passage40may direct incoming fluid-flow F at approximately a forty-five degree angle with respect to the axis of rotation R; this is represented inFIG. 6by a longitudinal axis L1. Other angles greater than or less than forty-five degrees are possible. InFIG. 6, incoming fluid-flow F travels from top to bottom in the inlet passage40. The outlet passage42may carry outgoing fluid-flow expelled out of the pump assembly10, and may communicate with the first and second primary passages44,46at a location downstream that at which the inlet passage40communicates with the first and second primary passages. The outlet passage42may be defined by an outlet surface50, and, like the inlet passage40, may have a generally cylindrical shape.

In this illustrated embodiment of the pump assembly10, the inlet passage40may include a first inlet passage52and a second inlet passage54. The first and second inlet passages52,54may be defined in part by the diverter18. The first inlet passage52may communicate with the first primary passage44, and the second inlet passage54may communicate with the second primary passage46. The first inlet passage52may direct incoming fluid-flow generally toward the first axial face28of the impeller12at the location of the vanes22, and generally toward the first primary passage44; and the second inlet passage54may direct incoming fluid-flow generally toward the second axial face30of the impeller at the location of the vanes and generally toward the second primary passage46. Referring in particular toFIG. 6, fluid-flow in the first inlet passage52may flow in the general axial direction, while fluid-flow in the second inlet passage54may flow along a more circuitous path. Fluid-flow in the second inlet passage54may travel axially past the impeller12, may impinge the inlet surface48at a closed bottom56(“bottom” relative to the orientation ofFIG. 6) of the inlet passage, and may be deflected toward the second primary passage46.

The first and second primary passages44,46may carry fluid-flow through the pump assembly10as the fluid-flow travels from the inlet passage40and to the outlet passage42. Referring toFIG. 6, the first primary passage44may be defined in part by a first primary surface58that, in this embodiment, may be located in the cover piece34and may be formed by the second bulged portion38. The first axial face28of the impeller12may also define a part of the first primary passage44. Similarly, the second primary passage46may be defined in part by a second primary surface60that, in this embodiment, may be located in the body piece32and may be formed by the first bulged portion36. The second axial face30of the impeller12may also define a part of the second primary passage46. The first and second primary passages44,46may communicate with each other and exchange fluid-flow via an axial passage45shown best inFIG. 5. The axial passage45may be defined in part by a side wall47of the housing16and by the circumferential periphery26of the impeller12, and may extend circumferentially around the housing between the inlet passage40and the outlet passage42. In cross-sectional profile like that shown inFIG. 6, each of the first and second primary passages44,46may have a generally half-circle shape. From the inlet passage40to the outlet passage42, each of the first and second primary passages44,46may have an abridged generally half-torus shape. The inlet passage40may initially communicate with the first primary passage44at a first entrance62, and the inlet passage may initially communicate with the second primary passage46at a second entrance64. The first and second primary passages44,46may each be open to the vanes22so that the first and second primary passages can communicate with the spaces located between neighboring individual vanes.

The diverter18may be a structure that may be used to veer, obstruct, or both veer and obstruct fluid-flow traveling through the inlet passage40. In the case of an air pump assembly, air flow may principally make its way into the spaces located between neighboring individual vanes22via the first and second primary passages44,46at the first and second axial faces28,30of the impeller12. It has been found that turbulent flow may be generated by initial impingement between incoming fluid-flow and the terminal ends24of the rotating vanes22, and between incoming fluid-flow and the axial faces28,30of the rotating impeller12at the location of the vanes. The turbulent flow may spread beyond the immediate region of initial impingement, and may interfere with and impede fluid-flow traveling in the first inlet passage52entering the first primary passage44, may interfere with and impede fluid-flow in the second inlet passage54traveling axially past the impeller12, may interfere with or impede fluid-flow traveling in the second inlet passage entering the second primary passage46, or a combination thereof. The diverter18may therefore veer fluid-flow away from impingement with the vanes22and/or axial faces28,30, may be an obstruction to impingement, or both, to thereby limit or altogether eliminate turbulent flow otherwise generated thereat. Fluid-flow may then travel through the inlet passage40and into the first and second primary passages44,46with greater ease, yielding improved fluid-flow efficiencies by as much as approximately eleven percent over some known inlet designs without diverters; fluid-flow improvements greater than eleven percent may also be possible.

The diverter18may have different designs and constructions, including that shown by a first embodiment inFIGS. 3-6. The diverter18may be made of a plastic material, and may be formed by an injection molding process. The diverter18may be located in the inlet passage40, and may be attached to or extend from the inlet surface48, or may be attached to or extend from the body piece32or the cover piece34. In the first embodiment, the diverter18may have a longitudinal axis that may be in general alignment and parallel to the longitudinal axis L of the inlet passage40. In the inlet passage40, the diverter18may be positioned so that it does not directly obstruct the entrances62,64from fluid-flow entering into the first and second primary passages44,46.

Referring toFIGS. 3-6, in the first embodiment the diverter18may have a generally U-shape with a first attachment, extension, or leg portion66; a second attachment, extension, or leg portion68; a confrontation or base portion70extending therebetween; and an opening72defined partly by the portions. Between the first and second leg portions66,68, the diverter18may have a circumferential width dimension that may be approximately equal to the diameter of the inlet passage40measured thereat. The first leg portion66may be attached to or may extend from the inlet surface48on one side thereof at the cover piece34, and the second leg portion68may be attached to or may extend from the inlet surface at the opposite side thereof at the cover piece. The base portion70may be suspended axially from the cover piece34and, in assembly, may generally directly confront and oppose the terminal ends24of the vanes22and the circumferential periphery26of the impeller12. The base portion70may have a first circumferential end74, a second circumferential end76, a first axial end78, and a second axial end80. Between the first and second circumferential ends74,76, the base portion70may have a circumferential width that may generally and substantially span the circumferential extent of the second inlet passage54so that bypassing fluid-flow F in the second inlet passage may not impinge the terminal ends24of the rotating vanes22. And between the first and second axial ends78,80, the base portion70may have an axial height that may generally and substantially span the full axial extent of the vanes22and may be approximately equal to the axial height dimension A of the circumferential periphery26, again so that bypassing fluid-flow F in the second inlet passage54may not impinge the terminal ends24of the rotating vanes. In other embodiments, both the circumferential width and the axial height of the base portion70may vary and may be greater than or less than the respective circumferential extent of the second inlet passage54and the axial height dimension A; in some applications and circumstances, it may be suitable to have some fluid-flow impinge the terminal ends24of the vanes22during use.

Further, the diverter18may have an inner or confrontation surface82, and may have an outer surface84located at an opposite radial side of the diverter. The outer surface84may directly face bypassing fluid-flow F in the second inlet passage54. The confrontation surface82, on the other hand, may directly confront the terminal ends24of the vanes22and the circumferential periphery26via a radial space. The radial space may have a radial length B that may be maintained at a constant value along its axial extent between the first and second axial ends78,80, and may be maintained at a constant value along its circumferential extent between the first and second circumferential ends74,76in which case the confrontation surface. may have a bowed and curved profile that follows the profile of the circumferential periphery26. In another embodiment, for example, the confrontation surface82may be generally planar in which case the radial length B has a greater value at the first and second circumferential ends74,76than at a circumferential centerpoint between the first and second circumferential ends. The radial length B may have a value that may be less than a radial thickness value of the diverter18, and, in one example, the radial length B may be approximately 0.6 mm or 1.0 mm; in other examples, other values for the radial length B are possible including values less than 0.6 mm, greater than 1.0 mm, or between 0.6 mm and 1.0 mm. As shown best inFIG. 6, the confrontation surface82may be arranged generally axially. Lastly, the confrontation surface82, the circumferential periphery26, and the radial space therebetween may constitute a confrontation region between the impeller12and the diverter18.

In use, fluid-flow F is drawn into the inlet passage40via the rotating impeller12. A portion of the incoming fluid-flow F may be drawn into the first inlet passage52and may enter the first primary passage44, and a portion of the incoming fluid-flow F may be drawn into the second inlet passage54and may enter the second primary passage46. Also, a portion of the incoming fluid-flow F may pass through the opening72between the first and second inlet passages52,54. In the second inlet passage54, bypassing fluid-flow F opposes the outer surface84of the diverter18as the fluid-flow makes its way to the second primary passage46. Because the diverter18—and in particular the confrontation surface82—may obstruct impingement between the bypassing fluid-flow F in the second inlet passage54and the terminal ends24of the vanes22, turbulent flow may be limited or altogether eliminated. The fluid-flow may therefore be substantially free to travel past the impeller12toward the closed bottom56substantially unimpeded by turbulent flow that would otherwise be generated without use of the diverter18.

FIGS. 7-9show a second embodiment of the pump assembly10. The second embodiment is similar to the first embodiment in many ways, and the similarities may not necessarily be repeated here for the second embodiment. One difference is the diverter18. In the second embodiment, the diverter18may include a first diverter86and a second diverter88. The first diverter86may be attached to or extend from the inlet surface48, may be attached to or extend from the body piece32or the cover piece34, or need not be attached to surfaces or pieces and instead may be attached to or extend from the second diverter88unattached to other structures. In the second embodiment, the first diverter86may have a generally rectangular shape and—unlike the diverter18in the first embodiment—may not have the opening72and may instead have an extended portion90. The extended portion90may have a circumferential width that may generally and substantially span the circumferential extent of the inlet passage40. The extended portion90may have an inner surface92. In use, the extended portion90, and in particular the inner surface92, may obstruct turbulence that may be generated between incoming fluid-flow F in the first inlet passage52and the first axial face28from spreading to the second inlet passage54, though this may be suitable in some applications and circumstances. Accordingly, bypassing fluid-flow F in the second inlet passage54travelling axially past the impeller12may not be interfered with or impeded by the spreading turbulence. Of course, as described below, turbulent flow in the first inlet passage52at the first axial face28may be limited or altogether eliminated by the second diverter88, such that in one embodiment the extended portion90may not be provided and instead the first diverter86may have the first and second leg portions and the opening as shown and described in the first embodiment. Furthermore, in other embodiments, the second diverter88may not be provided, whereby the first diverter86may be provided with the extended portion90alone. In this second embodiment, the first diverter86may have a first confrontation portion70and a first confrontation surface82, as previously described in the first embodiment.

The second diverter88may be attached to or may extend from the cover piece34—the attachment or extension is shown best inFIG. 9which shows the second diverter extending from a planar underside surface94of the cover piece34. In assembly, the underside surface94may directly confront the impeller12. The second diverter88may be located adjacent the first entrance62of the first primary passage44. The second diverter88may be arranged generally radially, while the first diverter86may be arranged generally axially such that the first and second diverters have an orthogonal relationship with respect to each other. The second diverter88may generally directly confront and oppose the first axial face28of the impeller12; in particular, the second diverter may span a portion or more of the radial extent of the vanes22so that the second diverter may, in a sense, radially overlap the vanes. As shown inFIG. 8, the second diverter88may have a circumferential width that may be less than the diameter of the inlet passage40to leave a circumferential space between a circumferential end95of the second diverter and a wall of the cover piece34; in another embodiment, the circumferential width may be approximately equal to the diameter of the inlet passage. The circumferential end95may partly define the first entrance62. Further, the second diverter88may have a second confrontation surface96and an outer surface98. The outer surface98may directly face incoming fluid-flow F in the first inlet passage52. The second confrontation surface96, on the other hand, may directly confront the first axial face28of the impeller12via an axial space. The axial space may have a value of approximately 0.35 mm, 0.6 mm, 1.0 mm, or some other value more, less, or in between these values. In use, the second confrontation surface96may obstruct impingement between incoming fluid-flow F and the first axial face28of the impeller12at the rotating vanes22. Turbulent flow may therefore be limited or altogether eliminated thereat, and incoming fluid-flow F may enter the first primary passage44substantially unimpeded by the turbulent flow that would otherwise be generated without the use of the second diverter88. The functionality of the first diverter86with respect to turbulent flow has been previously described.

FIG. 10shows a third embodiment of the pump assembly10. The third embodiment is similar to the second embodiment in many ways, and the similarities may not necessarily be repeated here for the second embodiment. One difference is the second diverter88. The second diverter88may be a separate and distinct piece from that of the first diverter86, and the second and first diverters may be spaced from each other via a radial space100. Like the second embodiment, the second diverter88may be attached to or may extend from the cover piece34. And like the first embodiment, the first diverter86may be attached to or may extend from the inlet surface48on one side or both sides thereof at the cover piece34.

FIG. 11shows a fourth embodiment of the pump assembly10. The fourth embodiment is similar to the second embodiment in many ways, and the similarities may not necessarily be repeated here for the second embodiment. One difference is the first diverter86. The first diverter86may not have the extended portion90of the second embodiment. In this embodiment, the first diverter86may extend from the second diverter88, and the first diverter may not necessarily be otherwise attached to the cover piece34or the body piece32.

Other embodiments—some of which have already been mentioned—that have not been described or shown are possible. For example, in any one of the first, second, third, or fourth embodiments, a third diverter could be provided. The third diverter could be located adjacent the second entrance of the second primary passage, could be arranged generally radially, and could generally directly confront and oppose the second axial face of the impeller to thereby limit or altogether eliminate generation of turbulent flow thereat. In another example, the diverter in any one of the embodiments could be attached to or could extend from the body piece instead or in addition to the cover piece.

The following is a description of select illustrative embodiments within the scope of the invention. The invention is not, however, limited to this description; and each embodiment and components, elements, and steps within each embodiment may be used alone or in combination with any of the other embodiments and components, elements, and steps within the other embodiments.

Embodiment one may include an air pump assembly. The air pump assembly may comprise an impeller, a housing, and a diverter. The impeller may have an axial face and a circumferential periphery. The housing may surround the impeller, and may form a part or more of a primary passage. The primary passage may be open to the impeller at the axial face. The housing may have an inlet passage that may communicate with the primary passage. The inlet passage may have a longitudinal axis that may be arranged generally non-orthogonally with respect to an axis of rotation of the impeller. The diverter may be located partially or more within the inlet passage. The diverter may have a surface that may confront the axial face of the impeller, may confront the circumferential periphery of the impeller, or may confront both the axial face and the circumferential periphery. During use of the air pump assembly, the diverter may inhibit generation of turbulent flow between incoming fluid-flow and the impeller where the surface confronts the impeller.

Embodiment two, which may be combined with embodiment one, further describes that the air pump assembly may include a motor connected to the impeller to rotate the impeller about the axis of rotation during use of the air pump assembly.

Embodiment three, which may be combined with any one of embodiments one and two, further describes that the axial face may include a first axial face and a second axial face. The primary passage may include a first primary passage and a second primary passage. The first primary passage may be open to the impeller at the first axial face, and the second primary passage may be open to the impeller at the second axial face. The inlet passage may communicate with the first and second primary passages.

Embodiment four, which may be combined with any one of embodiments one, two, and three, further describes that the housing may include a body piece and a cover piece that are attached together.

Embodiment five, which may be combined with any one of embodiments one, two, three, and four, further describes that the diverter may be arranged generally axially with respect to the impeller, and that the surface may confront the circumferential periphery of the impeller and may confront substantially the full axial extent of the circumferential periphery.

Embodiment six, which may be combined with any one of embodiments one, two, three, four, and five, further describes that the axial face may include a first axial face and a second axial face. The primary passage may include a first primary passage and a second primary passage. The first primary passage may be open to the impeller at the first axial face, and the second primary passage may be open to the impeller at the second axial face. The inlet passage may include a first inlet passage and a second inlet passage. The first inlet passage may communicate with the first primary passage and the second inlet passage may communicate with the second primary passage. The first and second inlet passages may be defined in part by the diverter. The diverter may extend upstream beyond the first axial face with respect to incoming fluid-flow. A portion or more of turbulence which may be generated between incoming fluid-flow in the first inlet passage and the first axial face may be obstructed by way of the diverter and may not substantially impede incoming fluid-flow in the second inlet passage.

Embodiment seven, which may be combined with any one of embodiments one, two, three, four, five, and six, further describes that the diverter may include a first diverter and a second diverter, and that the surface of the diverter may include a first surface of the first diverter and a second surface of the second diverter. The first surface may confront a portion or more of the circumferential periphery of the impeller, and the second surface may confront a portion or more of the first axial face of the impeller.

Embodiment eight, which may be combined with any one of embodiments one, two, three, four, five, six, and seven, further describes that the impeller may have numerous vanes. The diverter may be arranged generally radially with respect to the impeller. The surface may confront a portion or more of the radial extent of the vanes.

Embodiment nine may include a method. The method may comprise providing an air pump assembly that may comprise an impeller and a housing. The housing may surround the impeller. The impeller may have numerous vanes and an axial face. The vanes may have a circumferential periphery. The housing may form a part or more of a primary passage, and the primary passage may be open to the vanes at the axial face. The housing may have an inlet passage that may communicate with the primary passage. The inlet passage may have a longitudinal axis that may be arranged generally axially with respect to the impeller. The method may further comprise diverting a portion or more of incoming fluid-flow traveling through the inlet passage away from the axial face of the impeller, away from the circumferential periphery of the vanes, or away from both the axial face and the circumferential periphery.

Embodiment ten, which may be combined with embodiment nine, further describes diverting a portion or more of incoming fluid-flow by way of a diverter that may be located partially or more within the inlet passage. The diverter may have a surface that may confront a portion or more of the axial extent of the circumferential periphery of the vanes.

Embodiment eleven, which may be combined with any one of embodiments nine and ten, further describes diverting a portion or more of incoming fluid-flow by way of a diverter that may be located partially or more within the inlet passage. The axial face may include a first axial face and a second axial face. The primary passage may include a first primary passage and a second primary passage. The first primary passage may be open to the impeller at the first axial face, and the second primary passage may be open to the impeller at the second axial face. The inlet passage may include a first inlet passage and a second inlet passage. The first inlet passage may communicate with the first primary passage and the second inlet passage may communicate with the second primary passage. The first and second inlet passages may be defined in part by the diverter. The diverter may extend upstream beyond the first axial face with respect to incoming fluid-flow. A portion or more of turbulence that may be generated between incoming fluid-flow in the first inlet passage and the first axial face may be obstructed by way of the diverter and may not substantially impede incoming fluid-flow in the second inlet passage.

Embodiment twelve, which may be combined with any one of embodiments nine, ten, and eleven, further describes diverting a portion or more of incoming fluid-flow by way of a diverter. The diverter may be located partially or more within the inlet passage. The diverter may have a surface that may confront a portion or more of the radial extent of the vanes at the axial face of the impeller.

Embodiment thirteen, which may be combined with any one of embodiments nine, ten, eleven, and twelve, further describes diverting a portion or more of incoming fluid-flow by way of a first diverter and a second diverter. The first diverter may be located partially or more within the inlet passage, and the second diverter may be located partially, or more within the inlet passage. The first diverter may have a first surface that may confront a portion or more of the axial extent of the circumferential periphery of the vanes, and the second diverter may have a second surface that may confront a portion or more of the radial extent of the vanes at the axial face of the impeller.

Embodiment fourteen, which may be combined with any of the previous embodiments one through thirteen, may include an air pump assembly. The air pump assembly may comprise an impeller, a motor, a housing, and a diverter. The impeller may have numerous vanes, a first axial face, and a second axial face. The vanes may have a circumferential periphery. The motor may be connected to the impeller in order to rotate the impeller when the air pump assembly is in use. The housing may surround the impeller. The housing may form a part or more of a first primary passage. The first primary passage may be open to the vanes at the first axial face. The housing may form a part or more of a second primary passage. The second primary passage may be open to the vanes at the second axial face. The housing may have an inlet passage that may communicate with the first and second primary passages. The inlet passage may have a longitudinal axis that may be arranged generally axially with respect to the impeller. The diverter may have a surface that may confront a portion or more of the axial extent of the circumferential periphery of the vanes by way of a radial space, may confront a portion or more of the radial extent of the vanes by way of an axial space, or may confront both.

The above description of embodiments of the invention is merely illustrative in nature and, thus, variations thereof are not to be regarded as a departure from the spirit and scope of the invention.