Blower Assembly for Heat Pump Water Heater System

This application claims priority to U.S. Provisional Patent Application No. 63/640,656, filed Apr. 30, 2024, titled Blower Assembly for Heat Pump Water Heater System, and naming Steve Trimble et al. as inventors, the contents of which are hereby incorporated herein by reference.

The invention described herein is directed to a water heater system and, more particularly, a heat pump water heater system including an advantageous blower assembly.

The water heater system utilizes an evaporator coil to extract heat from a heat pump system and transfer the heat to the fluid inside a tank. An axial fan is positioned at the coil such that ambient air is pushed/pulled through the coil and subsequently directed into HVAC (heating ventilation and air cooling) ducting. The cooled air may then be circulated in the ambient atmosphere or the surrounding space. The heat pump system, the coil, and the axial fan are commonly placed within an enclosure having a base, a shroud, and a lid. The base is positioned in proximity to a top surface of the tank. Traditional blower assemblies for the water heater system lack adjustability that can impact the functionality and efficiency of the water heater system. Therefore, a need exists to modify the blower assembly functionality and control to increase performance, efficiency, and reduce noise.

This background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with supporting information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

The exemplary embodiments disclosed herein describe a water heater system including an advantageous blower assembly.

In one embodiment, a blower assembly for a water heater is provided. The blower assembly includes a blower inlet shroud having an inlet opening and an outlet opening and a scroll housing defining an outer surface, an outlet, and a spiral feature. The scroll housing and the blower inlet shroud are connected to each other and define an inner volume. The blower inlet shroud outlet opening is fluidly connected to the scroll housing inner volume. The blower assembly further includes an impeller wheel positioned within the inner volume defined by the blower inlet shroud and the scroll housing. The impeller wheel is configured to move a fluid from the blower inlet shroud inlet opening to the scroll housing outlet opening.

In another embodiment, a water heater system is provided. The water heater system includes a body including a water storage tank and a heat pump system connected to the body and in thermal connection with the water storage tank. The water heater system further includes a blower assembly including a blower inlet shroud having an inlet opening and an outlet opening and a scroll housing defining an outer surface, an outlet, and a spiral feature. The scroll housing and the blower inlet shroud are connected to each other and define an inner volume. The blower inlet shroud outlet opening is fluidly connected to the scroll housing inner volume. The water heater system further includes an impeller wheel positioned within the inner volume defined by the blower inlet shroud and the scroll housing. The impeller wheel is configured to move a fluid from the blower inlet shroud inlet opening to the scroll housing outlet opening.

As used herein, “a”, “an”, and “the” refer to both singular and plural referents unless the context clearly dictates otherwise.

As used herein, the term “about” refers to a measurable value such as a parameter, an amount, a temporal duration, and the like and is meant to include variations of +/−15% or less, preferably variations of +/−10% or less, more preferably variations of +/−5% or less, even more preferably variations of +/−1% or less, and still more preferably variations of +/−0.1% or less of and from the particularly recited value, in so far as such variations are appropriate to perform in the invention described herein. Furthermore, it is also to be understood that the value to which the modifier “about” refers is itself specifically disclosed herein.

As used herein, spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, “front”, “back”, “side”, “left”, “right”, “rear”, “top”, “bottom”, and the like, are used for ease of description to describe one element or feature's relationship to another element(s) or feature(s). It is further understood that the terms “front”, “back”, “left”, and “right” are not intended to be limiting and are intended to be interchangeable, where appropriate. Further, it should be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or relative importance, but rather are used to distinguish one element from another.

As used herein, the terms “comprise(s)”, “comprising”, and the like, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

As used herein, the terms “configure(s)”, “configuring”, and the like, refer to the capability of a component and/or assembly, but do not preclude the presence or addition of other capabilities, features, components, elements, operations, and any combinations thereof.

All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. Each range disclosed herein constitutes a disclosure of any point or sub-range lying within the disclosed range.

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”), is intended merely to better illustrate the invention and does not pose a limitation on the scope of the invention or any embodiments unless otherwise claimed.

Any combination or permutation of features, functions, and/or embodiments as disclosed herein is envisioned. Additional advantageous features, functions, and applications of the disclosed systems, methods, and assemblies of the present disclosure will be apparent from the description which follows, particularly when read in conjunction with the appended figures. All references listed in this disclosure are hereby incorporated by reference in their entireties.

The present disclosure describes a water heater system and, more particularly, a heat pump water heater system including an advantageous blower assembly. Referring to, a water heater systemincludes a heat pump system. In some embodiments, water heater systemincludes a heating element (not shown). Water heater systemincludes a body (not shown) that at least partially includes a storage tank for holding a fluid (e.g., water). Heat pump systemis in thermal connection with the storage tank (not shown) of water heater system. For example, heat pump systemis in thermal connection with water within the storage tank (not shown) of water heater system.

Water heater systemincludes a blower assemblyconfigured to transfer the heat from heat pump systemto the fluid inside the storage tank (not shown). Referring to, an advantageous blower assemblyincludes a scroll housingand an inlet component, or blower inlet shroud,. Scroll housingand blower inlet shroudare positioned relative to each other to define an inner volume, or volute,(). Scroll housingand blower inlet shroudare coupled with respect to each other. In some instances, scroll housingand blower inlet shroudare removably coupled with respect to each other. Inner volumeis defined by at least a plateof blower inlet shroudand a cavity() of scroll housing. Inner volumeis sized and shaped to receive one or more components of blower assembly, including, for example, an impeller wheel.

Blower assemblyis configured to draw a fluid (e.g., air) into inner volumethrough an outlet openingof blower inlet shroud, an inlet openingof blower assemblyand out outlet openingof scroll housing. Referring to, arrow A indicates the airflow entering blower assemblythrough outlet openingof blower inlet shroudand leaving blower assemblythrough outlet openingof scroll housing. Impeller wheelis positioned in axial alignment relative to outlet opening, as identified by axis C. Impeller wheelis rotatably coupled to a motorthat is coupled to housing, either directly or indirectly. Impeller wheelrotates about axis C to draw the fluid from inletof blower assemblyin the direction of arrow A and to move the fluid to scroll housing outlet openingin the direction of arrow B.

It should be understood that modifications may be made to the various components of blower assemblywithout departing from the spirit/scope of this disclosure. The individual components will be discussed in more detail below.

Referring to, blower inlet shroud platedefines outlet openingthat opens to inner volumeof blower assembly. Platemay be sized and shaped to engage with scroll housingand may include features/components that limit fluid leakage from inner volume. Blower inlet shrouddefines mounting features() that are positioned relative to plateand sized and shaped to engage with mounting features() of scroll housing. Mounting featuresare spaced around blower inlet shroud plate.

Blower inlet shroudincludes an entrance portionthat extends in a direction away from surface. Entrance portionincludes an upper edgepositioned opposite from outlet opening. Entrance portionis configured to direct a fluid (e.g., air) through outlet openingand into inlet opening. Outlet openingmay be centered with respect to Entrance portion(). The shape and size of entrance portionimpacts the quality of flow, including but not limited to, increasing air flow, reducing turbulence, reducing noise and/or reducing air recirculation. Entrance portionincludes one or more side walls. The number of side wallsmay depend, in part, on the shape of entrance opening.

Side wallsof entrance openingmay be angled, curved, or partially angled and partially curved. Upper edgemay define at least a portion of the shape of entrance portion. Inlet openingmay be circular, quadrilateral, triangular, and combinations thereof.

Outlet openingof blower inlet shroudmay have a diameter that is in the range of about 5.5 inches to about 7.5 inches. However, alternative diameter sizes may be selected without departing from the spirit/scope of this disclosure. Scroll housingof blower assemblydefines an outer surface() that is opposite from cavity(). Outer surfacemay be sized and shaped to resemble cavity. An openingextends between outer surfaceand cavityof scroll housing. Openingmay be sized and shaped to interface with motor(). Motormay extend at least partially into cavityfrom outer surface. Scroll housingincludes mounting features (not shown) that are positioned in proximity to opening. The mounting features may be configured to couple motorwith scroll housing.

Scroll housingdefines a flangethat extends outwardly therefrom. Flangemay extend at least partially around a perimeter of scroll housing(). Flangedefines mounting featuresthat are positioned at various points around the flangeand are configured to engage with mounting featuresof blower inlet shroud.

Scroll housingmay include various rib features,that create a web-like configuration relative to outer surface. Rib featureis positioned perpendicular relative to openingand, in some cases, extends to flange. Rib featureis positioned axial with openingat various distances from opening. Rib features,provide support to scroll housing

Cavityof scroll housingdefines a spiral featurethat is fluidly coupled to an outlet feature. Cavityof scroll housingtransitions from spiral featureto outlet feature(). Outlet featureis positioned in proximity to outlet openingsuch that fluid flows through outlet featureand out outlet opening.

Outlet featureis sized and shaped to exhaust fluid from inner volumeof blower assemblyso as to improve airflow therethrough. In some embodiments, outlet featuremay define a cross-section that is at least partially rectangular. The cross-section of outlet featuremay include radiused features to reduce (or eliminate) sharp corners. Cavity, including spiral featureand outlet feature, are sized and shaped to exhaust airflow with reduced turbulence, reduced recirculation, and/or reduced exhaust noise. Spiral featureand/or outlet featuredefine radiused portionsin proximity to a sidewallof cavity. Radiused portionsmay assist with directing the airflow smoothly by reducing turbulence. A reduction in turbulence may reduce the noise within scroll housingduring operation.

Spiral featureand outlet featureare sized and shaped to at least surround impeller wheel(). As depicted in, the distance between sidewallof cavityand sidewallof impeller wheelvaries at different locations along the length of spiral featureand outlet feature. For example, a neck portionis a position where spiral featureand outlet featuremeet. At neck portion, the distance Dbetween sidewallof impeller wheeland sidewallof cavitymay be one of the narrowest within the scroll housingand along spiral feature. In one embodiment, distance Dis the narrowest, or smallest, within scroll housing. The distance Dmay be between about 0.10 inches to about 0.40 inches. The distance Dbetween sidewallof impeller wheeland sidewallof cavitymay improve pressure within blower assemblyand reduce noise without affecting performance. The angle Xof neck portionshown inmay be between about 77 degrees and about 87 degrees. The angle Xof neck portionmay improve pressure and reduce turbulence and recirculation of the airflow within blower assembly.

Outlet openingof scroll housingis sized and shaped to provide at least a smooth transition as the fluid is exhausted from cavity. For example, outlet openingmay provide at least a smooth transition from outlet feature. Outlet openingmay define a shape that is oval, quadrilateral, square with fillet corners, rectangular with fillet corners, hexagon, octagon, circular, and combinations thereof. Outlet featuremay taper to outlet openingthat has a diameter of about 6 inches to about 10 inches. Referring to, outlet openingis flared such that the opening is larger than the cross-sectional area of outlet feature. Outlet featureand the outlet openingdefine flared portionsA,B,C,D that transition the cross-sectional area of outlet featureto the cross-sectional area of outlet opening. For example, outlet featuremay define a cross-sectional shape that is at least partially rectangular. Flared portionsA,B,C,D may provide a smooth transition as the fluid is exhausted from cavity, through the rectangularly-shaped outlet feature, and through outlet opening. Flared portionsA,B,C,D may each be similarly-sized, differently-sized, or some may be similarly-sized and some may be differently-sized. Flared portionsA,B,C,D may provide a smooth transition from cavityto outlet openingso as to reduce turbulence, thereby lowering the noise and improving the efficiency of blower assembly. Outlet openingmay define a first dimension measured between flared portionsA andC that is in the range of about 5.0 inches to about 8.0 inches. Outlet openingmay define a second dimension that is measured between flared portionsB andD that is in the range of about 1.0 inches to about 8.0 inches.

Referring to, impeller wheelincludes a base, an upper ringand a plurality of fan bladescoupled between baseand upper ring. Upper ringis positioned opposite base. The outer portions of base, upper ring, and the plurality of fan bladesdefine sidewallof impeller wheel. Impeller wheelincludes the axis C which extends through the center between baseand upper ring. Impeller wheeldefines an openingwhich is axial to the axis C. Openingmay be sized to receive a shaft, or the like, that is coupled motor. Referring to, impeller wheelmay have a diameter Dthat is between about 7 inches to about 10 inches. The distance Dbetween upper ringand the basemay be between about 3 inches and about 4 inches.

Referring to, basedefines a dome featurethat extends in the direction of upper ring. Dome featureis concentric with sidewallsuch that the axis C extends through the center of dome feature. Dome featuremay direct the airflow smoothly toward the plurality of fan blades. The shape of dome featuremay provide the airflow to move in a laminar nature thereby reducing the noise of the airflow. Referring to the cross-section of impeller wheel(), dome featuremay define a shape that is partially semicircular or entirely semicircular. If partially semicircular, the cross-section of dome featuremay include one or more curves.

For example, referring to, the cross-sectional shape of dome featuremay include about three (3) to about (7) distinct points, which in part, define the shape of dome feature. However, it should be understood that more points may be used, thereby producing, in some cases, a more detailed shape. In other instances, less points may be used.

Beginning with a first pointA, which is positioned closest to the axis C, first pointA has a horizontal dimension Afrom the axis C of about 0.72 inches to about 1.08 inches and a vertical dimension Afrom an offset of about 0.125 inches from dome, the vertical dimension Ais about 0.20 inches to about 0.30 inches. For example, the horizontal dimension Aof first pointA may be about 0.90 inches and the vertical dimension Aof first pointA may be about 0.25 inches. A second pointB, which is horizontally further from the axis C than first pointA, has a horizontal dimension Bfrom the axis C of about 1.5 inches to about 1.75 inches and a vertical dimension Bfrom domeof about 0.68 inches to about 1.02 inches. For example, the horizontal dimension Bof second pointB may be about 1.65 inches and the vertical dimension Bof second pointB may be about 0.85 inches. A third pointC, which is horizontally further from the axis C than second pointB, has a horizontal dimension Cfrom the axis C of about 1.56 inches to about 2.34 inches and a vertical dimension Cfrom domeof about 1.08 inches to about 1.62 inches. For example, the horizontal dimension Cof third pointC may be about 1.95 inches and the vertical dimension Cof third pointC may be about 1.35 inches. A fourth pointD, which is horizontally further from the axis C than third pointC, has a horizontal dimension Dfrom the axis C of about 1.96 inches to about 2.94 inches. Fourth pointD may be situated in proximity to an inner surface of base. For example, the horizontal dimension Dof fourth pointD may be about 2.45 inches. A fifth pointE, which is horizontally further from the axis C than fourth pointD, has a horizontal dimension Efrom the axis C of about 2 inches to about 3 inches. Fifth pointE may be situated in proximity to an outer surface of base. For example, the horizontal dimension Eof fifth pointE may be about 2.5 inches. The linear distance Lbetween fourth pointD and a sixth pointF may be about 0.10 inches. The thickness Tof dome featuremay be about 0.13 inches.

Fan bladesof impeller wheelinclude a first surfaceand an oppositely positioned second surface. Fan bladesinclude a first endthat extends between first and second surfaces,. Fan bladesinclude a second endthat is opposite from first end. In some instances, fan bladesmay have a cross-sectional shape that is rectangular such that first and second surfaces,are substantially parallel. In some instances and as depicted in, first and second surfaces,may each define a curve that extends between first endand second end. Second endis radiused and connects first surfaceto second surface. Each fan blademay have a cross-sectional shape that resembles an airfoil shape.

depict an advantageous fan bladeshape and design. The draft angle Gof each fan blademay be between about 0 degrees to about 5 degrees. However, it should be understood that the draft angle may vary depending on the number of fan blades. For example, the draft angle Gmay be greater when impeller wheelincludes fewer fan bladesand the draft angle Gmay be narrower when impeller wheelincludes more fan blades. The angle of attack Gof each fan blademay be between about 12 degrees to about 22 degrees. For example, the angle of attack Gof each fan blademay be between about 15 degrees to about 21 degrees. In a non-limiting example, the angle of attack Gof each fan bladeis about 17 degrees. The diameter of first surfacemay be between about 7 inches to about 11 inches. The diameter of second surfacemay be between about 4.5 inches to about 8.5 inches. The sweeping direction diameter of each fan blademay be between about 5.0 inches and about 7.0 inches. In a non-limiting example, angle G-of each fan bladeis between about 0.25 degrees to about 1.5 degrees. In a non-limiting example, the angle Gof each fan bladeis about 0.28 degrees. First surfacemay define a radius Rin proximity to second endthat is about 0.39 inches. Second surfacemay define a radius Rin proximity to second endthat is about 0.79 inches.

First and second surfaces,are defined by three (3) or more points that extend along the length of first and second surfaces,between first endand second end. Measured from second end, a first pointA along first surface, and a first pointA along second surfacehave a horizontal distance Aof about 0.47 inches to about 0.70 inches. For example, the horizontal distance Aof first pointsA,A may be about 0.59 inches. The distance Abetween first pointA along first surface, and a first pointA along second surfacemay be about 0.08 inches to about 0.12 inches. For example, the distance Abetween first pointsA,A may be about 0.10 inches. A second pointB along first surface, and a second pointB along second surface, which are further away from second endthan first pointsA,A, may have a horizontal distance Bof about 0.72 inches to about 1.09 inches. For example, the horizontal distance Bof second pointsB,B may be about 0.91 inches. The distance Bbetween second pointB along first surface, and second pointB along second surfacemay be about 0.064 inches to about 0.096 inches. For example, the distance Bbetween second pointsB,B may be about 0.08 inches. A third pointC along first surface, and a third pointC along second surface, which are further away from second endthan second pointsB,B, may have a horizontal distance Cof about 1.04 inches to about 1.56 inches. For example, the horizontal distance Cof third pointsC,C may be about 1.30 inches. The distance Cbetween third pointC along first surface, and third pointC along second surfacemay be about 0.048 inches to about 0.072 inches. For example, the distance Cbetween third pointsC,C may be about 0.06 inches. A fourth pointD along the first surfaceand in proximity to first end, and a fourth pointD along second surfaceand in proximity to first end, which are further away from second endthan third pointsC,C, may have a horizontal distance Dof about 1.13 inches to about 1.70 inches. For example, the horizontal distance Dof fourth pointsD,D may be about 1.42 inches. The distance Dbetween fourth pointD along first surface, and fourth pointD along second surfacemay be about 0.04 inches to about 0.06 inches. For example, the distance Dbetween fourth pointsD,D may be about 0.05 inches.

The number of fan bladesmay depend on the size (e.g., diameter) of impeller wheel, or on one or more performance characteristics (e.g., static pressure, adjustment in cubic feet per minute (CFM), power consumption, noise level, and revolutions per minute (RPM)) required by blower assemblyof water heater assembly, and combinations thereof. In some embodiments, impeller wheelmay include about 41 fan blades. In other embodiments, impeller wheelmay include about 50 fan blades. In some embodiments, impeller wheelmay include between about 47 fan bladesto about 53 fan blades.

illustrate an impeller wheelthat is a different embodiment of impeller wheel, as shown and described with respect to. Impeller wheelincludes features/components previously described with regard to impeller wheel. Thus, like parts/features will be numbered the same throughout the various embodiments. The features described with respect to one embodiment may apply to the other embodiments unless expressly stated otherwise.

Referring to, impeller wheelincludes a base, an upper ringand a plurality of fan bladescoupled between baseand upper ring. Upper ringis positioned opposite base. The outer portions of base, upper ring, and the plurality of fan bladesdefine sidewallof impeller wheel. Impeller wheelincludes the axis C which extends through the center between baseand upper ring.

Upper ringof impeller wheelincludes a plurality of raised portionsspaced around at least a portion of the circumference of upper ring. In one embodiment, upper ringincludes raised portionsspaced around the entirety of the circumference of upper ring. Raised portionsare spaced from each other and separated by a plurality of recessed portions including a first recessed portionand a second recessed portion. In some embodiments, each fan bladeis spaced from an adjacent fan bladeby a pair of raised portions, including a first raised portionA and a second raised portionB. It should be understood that first and second raised portionsA,B may be collectively referred to as reference numberand distinguishing between the two raised portionsenables a more thorough explanation of impeller wheel. It does not, however, inherently indicate differences between the two raised portions, unless otherwise expressly stated. The pair of raised portionsmay include a pair of raised portionsA, a pair of raised portionsB, or a pair that includes the raised portionA and the raised portionB. In other embodiments, more or less raised portionsA,B may be positioned relative to each fan blade.

Raised portionsare positioned on a first surfaceof upper ring. As depicted, first surfaceis a top surface of upper ring. Although depicted on top surfaceof upper ring, raised portionsmay be situated on a different surface of upper ring(e.g., side surface, bottom surface). Raised portionsmay be angled relative to sidewallof impeller wheel. For example, raised portionsmay not be perpendicular relative to sidewallof impeller wheel. Upper ringdefines an outside surfaceA that is positioned proximate to sidewalland an inside surfaceB positioned opposite from outside surfaceA. In some instances, outside surfaceA of upper ringhas a radius extending from the axis C that is equal to the radius of sidewall. In other instances, outside surfaceA has a radius extending from the axis C that is shorter or longer than the radius of sidewall. Raised portionsmay extend at least between outside surfaceA and inside surfaceB of upper ring. In other instances, raised portionsextend beyond at least one of outside surfaceA and/or inside surfaceB of upper ring. In other instances, raised portionsextend a distance between outside surfaceA and/or inside surfaceB.

In some instances, raised portionA and raised portionB may be similarly sized and shaped. In other instances, raised portionA and raised portionB may be differently sized and shaped. Raised portionsdefine a first recessed portionand a second recessed portion. Therefore, the size and shape of recessed portions,may resemble the periphery of raised portionsA,B. For example, a portion of the periphery of first raised portionA and a portion of the periphery of second raised portionB may define, at least in part, the size and shape of first recessed portion. A portion of the periphery of first raised portionA and a portion of the periphery of second raised portionB may define, at least in part, the size and shape of second recessed portion.

In operation, as airflow travels through recessed portions,, recessed portions,create a disruption to the airflow. The disruption to the airflow reduces the noise emitted by blower assembly. In some instances, recessed portions,have reduced the overall surface acoustic sound level of blower assemblyby about 4 percent.

In a non-limiting example,depicts dimensions of the recessed portions,. As noted above, raised portionsdefine first recessed portionand second recessed portion. For example, first raised portionA having a first sidedefines a first side of first recessed portionand second raised portionB having a second sidedefines a second side of first recessed portion. The distance Wbetween first sideof first raised portionA and second sideof second raised portionB in proximity to outside surfaceA of upper ringmay be about 0.10 inches to about 0.16 inches. For example, the distance Wmay be about 0.13 inches. The distance Wbetween first sideof first raised portionA and second sideof second raised portionB in proximity to inside surfaceB of upper ringmay be about 0.16 inches to about 0.24 inches. For example, the distance Wmay be about 0.20 inches.

Second raised portionB having a first sidedefines a first side of second recessed portionand first raised portionA having a second sidedefines a second side of second recessed portion. The distance Wbetween first sideof second raised portionB and second sideof first raised portionA in proximity to outside surfaceA of upper ringmay be about 0.10 inches to about 0.16 inches. For example, the distance Wmay be about 0.13 inches. The distance Wbetween first sideof second raised portionB and second sideof first raised portionA in proximity to inside surfaceB of upper ringmay be about 0.16 inches to about 0.24 inches. For example, the distance Wmay be about 0.20 inches.

illustrate an impeller wheelthat is an alternative embodiment of impeller wheel, as shown and described with respect to, of blower assembly, as shown and described with respect to. Impeller wheelincludes features/components previously described with regard to impeller wheel. Thus, like parts/features will be numbered the same throughout the various embodiments. The features described with respect to one embodiment may apply to the other embodiments unless expressly stated otherwise.

Referring to, impeller wheelincludes a base, an upper ringand a plurality of fan bladescoupled between baseand upper ring. Upper ringis positioned opposite base. The outer portions of base, upper ring, and plurality of fan bladesdefine sidewallof impeller wheel. Impeller wheelincludes the axis C which extends through the center between baseand upper ring.

Upper ringof impeller wheelincludes a plurality of raised portionsspaced around at least a portion of the circumference of upper ring. In one embodiment, upper ringof impeller wheelincludes a plurality of raised portionsspaced around the entirety of the circumference of upper ring. Raised portionsare spaced from adjacent raised portionsand separated therefrom by a first recessed portionand a second recessed portion. In some instances, each fan blademay be spaced from adjacent fan blades by a pair of raised portions, including a first raised portionA and a second raised portionB. It should be understood that first and second raised portionsA,B may be collectively referred to as reference numberand distinguishing between the two raised portionsenables a more thorough explanation of the impeller wheel. It does not, however, inherently indicate differences between the two raised portions, unless otherwise expressly stated. The pair of raised portions, may include a pair of raised portionsA, a pair of raised portionsB, or a pair that includes raised portionA and raised portionB. However, more or less raised portionsmay be positioned relative to each fan blade.

Raised portionsare positioned on a first surfaceof upper ring. As depicted, first surfaceis a bottom surface of upper ring. Although depicted on bottom surfaceof upper ring, raised portionsmay be situated on a different surface of upper ring(e.g., side surface, top surface). Raised portionsmay be angled relative to sidewallof impeller wheel. For example, raised portionsmay not be perpendicular relative to sidewallof impeller wheel. Upper ringdefines an outside surfaceA positioned proximate sidewalland an inside surfaceB positioned opposite outside surfaceA. In some instances, outside surfaceA of upper ringhas a radius extending from the axis C that is equal to the radius of sidewall. In other instances, outside surfaceA has a radius extending from the axis C that is shorter or longer than the radius of sidewall. Raised portionsmay extend at least between outside surfaceA and inside surfaceB of upper ring. In other embodiments, raised portionsextend beyond at least one of outside surfaceA and/or inside surfaceB of upper ring. In still other embodiments, raised portionextends a distance between outside surfaceA and/or inside surfaceB of upper ring.

In some embodiments, raised portionA and raised portionB are similarly sized and shaped. In other embodiments, raised portionA and raised portionB are differently sized and shaped. Raised portionsdefine first recessed portionand second recessed portion. Therefore, the size and shape of recessed portions,resemble the periphery of raised portionsA,B. For example, a portion of the periphery of first raised portionA and a portion of the periphery of second raised portionB may define, at least in part, the size and shape of first recessed portion. A portion of the periphery of first raised portionA and a portion of the periphery of second raised portionB may define, at least in part, the size and shape of the second recessed portion.