TECHNICAL FIELD
The field to which the disclosure generally relates includes products including an inlet design for a pump assembly and the pump assembly itself.
BACKGROUND
Fluid pumps having impellers are commonly designed with a fluid inlet passage that directs fluid axially in relation to the impeller at a center of the impeller or at its blades. One example of such a fluid pump is a secondary air pump assembly that supplies secondary air to an automotive exhaust system to reduce pollutants in the exhaust gases.
SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION
One embodiment of the invention includes a product comprising at least a housing and impeller. The housing comprises an inlet portion which in turn defines an inlet passage. The inlet passage leads to the impeller and directs fluid flow substantially perpendicular with respect to an axis of rotation of the impeller.
Another embodiment of the invention includes a product comprising a pump assembly which itself comprises a housing, an electric motor, and an impeller. The housing forms an inlet portion which defines an inlet passage. The electric motor is at least partially carried by the housing. The impeller is located in the housing and is driven by the electric motor. The impeller has a plurality of blades. A center of flow of a fluid coming out of the inlet passage is directed generally parallel to a radially oriented plane defined by the impeller.
Another embodiment of the invention includes a product comprising a secondary air pump assembly which itself comprises a housing, an electric motor, and an impeller. The housing comprises an inlet portion defining an inlet passage, and an outlet portion. The electric motor is at least partially carried by the housing. The impeller is located in the housing and is driven by the electric motor. The impeller defines an axis of rotation, a circumference, and a radially oriented plane. A center of flow of air coming out of the inlet passage lies perpendicular to the axis of rotation and parallel to the radially oriented plane.
Other exemplary embodiments of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 illustrates a schematic of one embodiment of a secondary air system that includes a pump assembly.
FIG. 2 illustrates a partial sectional view of one embodiment of the invention including a product including a pump assembly.
FIG. 3 illustrates a top view of one embodiment of the invention including a product including a pump assembly.
FIG. 4 illustrates a perspective view of one embodiment of an impeller showing several relationships of a center of fluid flow with respect to the impeller.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The following description of the embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring now to FIGS. 1-3, one embodiment of the invention includes a product that may be an inlet 10 for a fluid pump designed to increase overall efficiency in some embodiments of the fluid pump by, among other things, reducing turbulence to thus reduce load and hence current draw. In at least one embodiment, the fluid flow of the fluid pump is increased by about 1 SCFM, and the current draw is reduced by about 2.5-3.0 Amperes. The inlet 10 may be incorporated in a pump assembly 12 which in this example is a secondary air pump assembly as used in a secondary air system 13 (FIG. 1) of an automotive exhaust system to reduce pollutants in the exhaust gases. The secondary air system 13 may also include an air filter 15 that filters air before it is received in the pump assembly 12, a secondary air valve 17, and a catalytic converter 19 which could also be a diesel particulate filter in other embodiments. In this system, the pump assembly 12 discharges air to the catalytic converter 19 to mix with exhaust gases coming from an engine 21. Skilled artisans will know the general construction, arrangement, and operation of these types of secondary air systems such that a more complete description will not be given here.
The inlet's 10 design may be incorporated in other pump assemblies having impellers such as those that pump air or liquid, and those with impellers of the semi-open type, enclosed type, two-stage compression type, and the like. The pump assembly 12 may be of the regenerative pump type. Referring to FIGS. 2 and 3, the pump assembly 12 shown may include a housing 14 to accommodate an electric motor 16 that drives an impeller 34 for energizing air. The housing 14 may at least partially carry the electric motor 16 and may shelter and support the impeller 34, and may also provide acoustic insulation for one or both of them. The housing 14 may be made in one-piece, or made up of several pieces subsequently put together. It may be constructed of a metal such as aluminum or steel, or a plastic such as a polymeric or composite material, or the like. Still, in some embodiments, some parts may be composed of one material while other parts may be composed of another material. As shown, the housing 14 may include a first cover 20 adjacent the impeller 34 and a second cover 22 adjacent the electric motor 16. The first cover 20 may form an inlet portion 24 and an outlet portion 26 which respectively define an inlet passage 28 and an outlet passage (not shown). In other embodiments, the inlet portion 24 may be formed partially by the first cover 20 and partially by another portion of the housing 14, or may be formed entirely by another portion of the housing 14 and not at all by the cover 20. The inlet passage 28 may have a circular cross-section with a diameter of 22.4 mm, or it may have other size diameters and may have various irregularly shaped cross-sections like a polygon. The exact size and shape may be partly dependent on desired fluid flow characteristics. The outlet passage may also have a circular cross-section or other cross-sections.
The electric motor 16 may provide mechanical energy to drive the pump assembly 12. The electric motor may be a d.c. motor or other type. In some embodiments, the electric motor 16 may be enclosed by the second cover 22 as shown, and in other embodiments, the electric motor 16 may be attached to and supported by the housing 14 without the cover 22. The electric motor 16 may drive the impeller 34 through a shaft 32. And although not specifically shown, the electric motor 16 may further include a stator surrounding at least one rotor. Skilled artisans will know the general construction, arrangement, and operation of these types of motors such that a more complete description will not be given here.
The impeller 34 energizes incoming air from the inlet portion 24 and then discharges the air out the outlet portion 26. The impeller 34 is rotated about the shaft 32 to direct air outwardly to an annular channel 36 and away from the center of rotation. The impeller 34 may come in many designs including the one shown in FIG. 4. In general, the impeller 34 may have a circular or cylindrical shape which defines an axis of rotation 38, a circumference 40, and a radially oriented plane 42. The axis of rotation 38 shown may be an imaginary line that projects through the center of rotation and along an axis of the cylindrical shape of the impeller 34. The circumference 40 shown may be an imaginary circle outside of the axis of rotation 38 and generally around a circumference of the cylindrical shape of the impeller 34. And the radially oriented plane 42 shown may be an imaginary plane that is perpendicular to the axis of rotation 38 and that may intersect the circumference 40, be parallel to the circumference 40, or both. In this regard, the term “axially” may describe a direction that is along an axis of the cylindrical shape of the impeller 34, including along the axis of rotation 38; the term “circumferentially” may describe a direction that follows a circumference of the cylindrical shape of the impeller 34, including the circumference 40; and the term “radially” may describe a direction that follows a radius of the cylindrical shape of the impeller 34, and that may be perpendicular to the axis of rotation 38, in the radially oriented plane 42, or both.
Still referring to FIG. 4, the impeller 34 may be made in one-piece, or made up of several pieces subsequently put together. It may be constructed of a metal such as aluminum or steel, or a plastic such as a polymeric or composite material, or the like. Still, in some embodiments, some parts may be composed of one material while other parts may be composed of another material. The impeller 34 may have a gauge or axial thickness of 12 mm, or it may have other size gauges depending partly upon the desired fluid flow. As shown, the impeller 34 may include a plurality of axially and radially extending vanes or blades 44 disposed circumferentially about a body 46. The blades 44 may be designed and oriented in a number of ways, including that shown as being axially oriented with respect to the impeller 34. For example, the blades 44 may be slightly bent as shown, concave or convex, flat, or the like. Each of the plurality of blades 44 may have a face 48 looking in a direction of rotation A of the impeller 34. Each face 48 has a geometric center which lies at about the middle of the face. The body 46 may have a center of rotation about the axis of rotation 38, and may define a surface 50 which may be parallel with or may lie within the radially oriented plane 42.
When in use, the pump assembly 12 generally energizes fluid, such as air, coming from the inlet passage 28 and discharges the air out the outlet passage. The inlet portion 24 may be designed to direct air toward the impeller 34 such that the air flows substantially perpendicular with respect to the axis of rotation 38 and generally parallel to the radially oriented plane 42. For the sake of description, the flow of air may be represented by a center of flow line B in FIG. 4. In one embodiment, a center of flow line B′ may be directed substantially tangentially with respect to the circumference 40. In other words, at least some of the flow of air may contact the circumference 40 at a single point. Of course, not all of the flow of air in this embodiment is tangential in this sense. In another embodiment, a center of flow line B″ is directed generally at the middle of the faces 48 that are adjacent the inlet portion 24 or exposed to the flow of fluid. In another embodiment, a center of flow line B′″ is directed at and perpendicularly intersects the axis of rotation. In all embodiments, the center of flow B may reduce turbulence by virtue of its direction.
The above description of embodiments of the invention is merely exemplary in nature and, thus, variations thereof are not to be regarded as a departure from the spirit and scope of the invention.
Patent Application
20100172777
