AXIAL FAN ARRANGEMENT, INCLUDING AN INTERMEDIATE COVER

Abstract

An axial fan assembly comprising an axial fan and an intermediate shroud. The axial fan includes a hub and one or more blades extending radially from a center point of the hub about which the axial fan rotates relative to a rotational axis, each of the one or more blades extending beyond a blade length to a free edge defining an outermost edge of the one or more blades. The intermediate shroud is disposed radially outwardly of the hub and radially inwardly of the free edge of the one or more blades. The intermediate shroud is disposed proximate the free edge of the one or more blades to increase the stability of the one or more blades.

Description

CROSS REFERENCE TO RELATED APPLICATIONThis application claims priority to U.S. Non-Provisional Patent Application No. 18 / 541,499, filed Dec. 15, 2023, the entire disclosure of which is hereby incorporated by reference in its entirety.REGIONThe embodiments described herein relate generally to axial flow fans, and more particularly to an axial flow fan assembly that includes an axial flow fan that includes one or more blades and an intermediate shroud proximate a blade tip of the one or more blades.BACKGROUNDAt least some known axial fan assemblies include an axial fan having one or more blades configured to improve performance of the axial fan assembly. For example, the one or more blades may be constructed to have a minimum blade thickness and / or complex curves to improve the performance of the axial fan. However, blades of small thickness and / or complex curves may be more prone to blade bending and / or blade tip flutter due to the considerable size of the blades and the vibrations experienced during operation of the axial fan assembly.Therefore, there is a need for an axial flow fan assembly that includes an axial flow fan having one or more blades and an intermediate cover proximate a blade tip of the one or more blades to facilitate damping vibrations, reduce friction, and improve airflow.BRIEF DESCRIPTIONIn one aspect, an axial fan assembly is disclosed. The axial fan assembly includes an axial fan including a hub and one or more blades extending radially from a center of the hub about which the axial fan rotates relative to a rotational axis, each of the one or more blades extending beyond a blade length to a free edge defining an outermost edge of the one or more blades. The axial fan assembly also includes an intermediate cover disposed radially outward of the hub and radially inward of the free edge of the one or more blades, the intermediate cover disposed proximate the free edge of the one or more blades to increase stability of the one or more blades.In another aspect, a method of using an axial fan assembly is disclosed. The method includes providing an axial fan including a hub and one or more blades extending radially from a center of the hub about which the axial fan rotates relative to a rotational axis, each of the one or more blades extending outward a blade length to a free edge defining an outermost edge of the one or more blades. The method also includes disposing an intermediate cover radially outward of the hub and radially inward of the free edge of the one or more blades, the intermediate cover disposed proximate the free edge of the one or more blades, and rotating the axial fan, the intermediate cover increasing stability of the one or more blades.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 shows a front perspective view of an axial flow fan assembly according to one or more embodiments of the present disclosure. FIG. 2 shows a lateral cross-sectional view of the axial fan arrangement from FIG. 1. FIG. 3 shows an enlarged view of detail A-A of the axial fan arrangement from FIG. 2. FIG. 4 shows a side cross-sectional view of another embodiment of an axial fan assembly. FIG. 5 shows an enlarged view of detail B-B of the axial fan arrangement from FIG. 4. FIG. 6 shows a front view of an axial fan assembly according to another embodiment of the present disclosure. FIG. 7 shows a side cross-sectional view of the axial fan arrangement from FIG. 6.DETAILED DESCRIPTIONAn axial fan assembly including an axial fan having one or more blades and an intermediate cover proximate a blade tip of the one or more blades is provided in accordance with various embodiments of the present disclosure.FIG. 1 shows a front perspective view of an axial flow fan assembly 100, in accordance with one or more embodiments of the present disclosure. The axial fan assembly 100 includes a hub 102 and one or more blades 104 extending radially from and circumferentially around the hub 102. The hub 102 includes a first end 106, a second end 108, and a pivot axis 110 that extends laterally through opposing first and second ends 106 and 108, respectively (shown in FIG. 2 ). Moreover, the hub 102 includes a sidewall 111 that extends from the first end 106 to the second end 108. The hub may be connected to one or more components, such as components of an airflow system, by hemming, welding, fastening, and / or, optionally, press-fitting. The center 112 of the hub 102 is aligned with the axis of rotation 110 (shown in FIG. 2 ).Each of the one or more blades 104 includes a free edge 114 defining an outermost edge of the blade 104 as measured from the center 112 of the hub 102, and a blade tip 115 defined along the free edge 114 defining an outermost end of the blade 104 as measured from the center 112 of the hub 102. Additionally, each of the one or more blades 104 includes a coupled end 116 connected to the sidewall 111 of the hub 102. In some embodiments, the sidewall 111 may extend substantially parallel to the axis of rotation 110. In other embodiments, the side wall 111 may extend at an angle to the axis of rotation 110. The shape of the one or more blades 104 may be any suitable shape that enables the axial fan assembly 100 to function as described herein. Additionally, the shape of the free edge 114 of the one or more blades 104 may have any suitable shape that enables the axial fan assembly 100 to function as described herein.The one or more blades 104 extend a blade length 118 measured radially from the sidewall 111 of the hub 102 (shown in FIG. 2 ). During operation of the axial fan assembly 100, the blade length 118 may contribute to deflection of the one or more blades 104 and / or to flutter of the free edge 114 and / or blade tip 115 of the one or more blades 104. For example, the significant size of the one or more blades 104 and / or the vibration resulting from the operation of the axial fan assembly 100 may result in reduced stability of the one or more blades 104. Therefore, the axial fan assembly 100 also includes an intermediate cover 120 proximate the free edge 114 of the one or more blades to enable improved stability, airflow generation, reduced blade flutter, and / or improved fatigue life. The blade length 118 may range from about 2.5 inches (0.0635 meters) to about 5.5 inches (0.1397 meters).FIG. 2 shows a side cross-sectional view of the axial fan assembly 100, and FIG. 3 shows an enlarged view of the axial fan assembly 100. The intermediate cover 120 has a circular shape and is endless. The intermediate cover 120 is radially offset from the hub 102. The radial offset between the hub 102 and the intermediate cover 120 is substantially constant along the cover. The intermediate cover 120 has a lateral dimension 121 measured between a first cover end 122 and a second cover end 124. In some embodiments, the intermediate cover 120 may extend substantially parallel to the axis of rotation 110 and / or the sidewall 111 of the hub 102. In other embodiments, the intermediate cover 120 may extend at an angle from the axis of rotation 110 and / or the sidewall 111 of the hub 102.The intermediate cover 120 may be a distance 126 measured between the intermediate cover 120 and the sidewall 111 of the hub 102. The distance 126 between the intermediate cover 120 and the sidewall 111 may range from about 60% of the distance between the sidewall 111 and the blade tip 115 to about 90% of the distance between the sidewall 111 and the blade tip 115.Additionally, the intermediate cover 120 may be disposed proximate to the blade tip 115. The blade tip 115 and the intermediate cover 120 may be separated by a distance 128 from the blade tip 115 of the one or more blades 104. The distance 128 between the intermediate cover 120 and the blade tip 115 may range from about 10% of the distance between the sidewall 111 and the blade tip 115 to about 40% of the distance between the sidewall 111 and the blade tip 115.The intermediate cover 120, which is positioned proximate the free edge 114 and / or the blade tip 115 of the one or more blades 104, such as with the clearance 128 between the intermediate cover 120 and the blade tip 115, may facilitate improved efficiency and / or production of the axial fan assembly 100. For example, the intermediate cover 120 may increase the stability of the one or more blades 104 by adding structural support along the blade length 118 of the blades 104. As a result of the increased stability of the vanes 104, the intermediate cover 120 may facilitate an increase in the flow achieved by operation of the axial fan assembly 100 and / or an increase in the uniformity of the airflow generated by the axial fan assembly 100.FIG. 4 shows a side cross-sectional view of an axial fan assembly 200, and FIG. 5 shows an enlarged view of the axial fan assembly 200. The axial fan assembly 200 shown in FIG. 4 is similar to the axial fan assembly 100 shown in FIG. 2 with the differences indicated below, and therefore the same reference numerals are used for the same components as in FIG. 2 in FIG. 4. The axial fan assembly 200 includes an intermediate cover 220. The intermediate cover 220 is substantially similar to the intermediate cover 120 (shown in FIG. 2 ) because the intermediate cover 220 has a circumferential shape, is endless, and is positioned with a substantially constant radial offset along the hub 102.The intermediate cover 220 has a lateral dimension 221 measured between a first cover end 122 and a second cover end 124. The lateral dimension 221 may be such that the intermediate cover 220 extends through a leading edge and a trailing edge of the blade 104. For example, the lateral dimension 221 may extend up to 0.5 inches (0.0127 meters) beyond the leading edge of the blade 104. Moreover, the lateral dimension 221 may extend beyond the trailing edge of the blade 104, for example, up to 1.5 inches (0.0381 meters).The axial fan assembly 200 may be used in conjunction with a plurality of blades 230 downstream of one or more blades 104. Each of the plurality of blades 230 includes a leading edge 232 of the blade (shown in FIG. 5 ). The second cover end 124 of the intermediate cover 220 may be separated from the leading edge 232 of the plurality of vanes 230 by a gap 234. That is, the lateral dimension 221 of the intermediate cover 220 may be such that the second cover end 124 of the intermediate cover 220 is separated from the leading edge 232 of the plurality of vanes 230 by the gap 234. The gap 234 between the second cover end 124 of the intermediate cover 220 and the leading edge 232 of the plurality of blades 230 may range from about 0.05 inches (0.00127 meters) to about 1 inch (0.0254 meters). In some embodiments, at least one of the first shroud ends 122 and / or the second shroud end 124 may be aerodynamically shaped to facilitate uniform airflow between the axial fan assembly 200 and the plurality of vanes 230. For example, at least one of the first cover ends 122 and / or the second cover end 124 may have an elliptical shape with a height to width ratio between 1:1 and 4:1.FIG. 6 shows a front view of an axial fan arrangement 300. The axial fan arrangement 300 shown in FIG. 6 is similar to the axial fan arrangement 100 shown in FIG. 2 and the axial fan arrangement 200 shown in FIG. 4, with the differences indicated below, so that the same reference numerals are used for the same components as in FIGS. 2 and 4 in FIG. 6. The axial fan assembly 300 includes an intermediate cover 320. The intermediate cover 320 is similar to the intermediate cover 120 (shown in FIG. 2 ) and the intermediate cover 220 (shown in FIG. 4 ) because the intermediate cover 320 is endless and is disposed with a radial offset along the hub 102.The intermediate cover 320 has a sinusoidal circumferential shape that includes one or more shafts 340. The varying shape of the shafts 340 is such that the radial offset of the intermediate cover 320 along the hub 102 is not continuous. That is, each shaft 340 includes a shaft start 342 and a shaft end 344, wherein the radial offset along the hub 102 of each of the shafts 340 varies between the shaft start 342 and the shaft end 344. The radial offset decreases from the shaft beginning 342 to a shaft trough 345, increases from the shaft trough 345 to a shaft apex 346, and decreases from the shaft apex 346 to the shaft end 344. A shaft height 347 measured between the radial offset along the hub 102 at the shaft valley 345 (circle A in FIG. 6 ) and the radial offset along the hub at the crest 346 (circle B in FIG. 6 ) may vary between 0.3 inch (0.00762 meter) and 1 inch (0.0254 meter).The sinusoidal shape of the intermediate cover 320 formed by one or more shafts 340 facilitates reducing the sound of the axial fan assembly 300, such as the harmonic sound and / or the blade through sound. In some embodiments, as shown in FIG. 6, each shaft 340 may be located between a leading edge 348 of adjacent blades 104. In other embodiments, each shaft 340 may be located between a trailing edge 350 of adjacent blades 104. In still other embodiments, the shaft start 342 of each shaft 340 may be located between any point of adjacent blades 104 at a distance from a central angle. The central angle is defined as the number of degrees in a circle divided by the number of blades. The number of shafts 340 including the central angle may be between a minimum of one and a maximum of three. In some embodiments, the center of the shaft 340 may be half the arc length and / or half the central angle of the shaft. In other embodiments, the center of the shaft 340 may not be half the arc length and / or half the center angle of the full shaft, such that one half of the shaft 340 has a greater arc length than the other half.FIG. 7 shows a side cross-sectional view of the axial fan assembly 300. The intermediate cover 320 has a lateral dimension 321 measured between the first cover end 322 and the second cover end 324. The lateral dimension 321 may be such that the intermediate cover 320 extends through the leading edge 348 and the trailing edge 350 of the blade 104. For example, the lateral dimension 321 may extend up to 0.5 inches (0.0127 meters) beyond the leading edge 348 of the blade 104 (shown as distance D in FIG. 7 ). Moreover, the lateral dimension 321 may extend beyond the trailing edge 350 of the blade 104 (shown as distance C in FIG. 7 ), for example, up to 1.5 inches (0.0381 meters).The intermediate cover 320 may include one or more balancing features to enable improved balancing of the axial fan assembly 300. For example, the intermediate cover may include one or more slots 352 in the second cover end 324. In some embodiments, the number of slots 352 may be equal to the number of blades 104. In other embodiments, the number of slots 352 may be a multiple of the number of blades 104. Material may be introduced into the one or more slots 352 to balance the axial fan assembly 300 and allow less interference with airflow and airflow near the blades 104 than if material were attached to one or more edges of the blades 104. Also, less material may need to be added to balance the axial fan assembly 300 when added to the intermediate cover 320 than closer to the center of the axial fan assembly 300. Although the slots 352 are shown as part of the axial fan assembly 300, the slots 352 may also be attached to the intermediate cover of the axial fan assembly 100 (e.g., the intermediate cover 120) and / or the axial fan assembly 200 (e.g., the intermediate cover 220).Additionally, the intermediate cover 320 may include, for example, one or more protrusions 354 in the second cover end 324. In some embodiments, the number of protrusions 354 may be equal to the number of blades 104. In other embodiments, the number of protrusions 354 may be a multiple of the number of blades 104. The protrusions 354 may provide a region for ablating material, e.g., by drilling, to reduce mass in a particular region and balance the axial fan assembly 300. Less material may need to be removed to balance the axial fan assembly 300 when it is removed from the intermediate cover 320 than closer to the center of the axial fan assembly 300. Although the protrusions 354 are shown as part of the axial fan assembly 300, the protrusions 354 may be included in the intermediate cover of the axial fan assembly 100 (e.g., the intermediate cover 120) and / or the axial fan assembly 200 (e.g., the intermediate cover 220).Additionally, material may be added and / or removed from the intermediate cover 320 during the molding / casting process. In some embodiments, the intermediate cover 320 may be manufactured by an injection molding process that includes adjustable cores in the mold to adjust the amount of material injected into particular areas to allow for improved balancing of the axial fan assembly 300. During the molding / casting process, material may be added or removed from the intermediate cover of the axial fan assembly 100 (e.g., the intermediate cover 120) and / or the axial fan assembly 200 (e.g., the intermediate cover 220).A technical effect of the system described herein includes at least one of: (a) improved stability of one or more blades of an axial fan; (b) increased flow velocity achieved by operation of the axial fan; (c) increased uniformity of air flow generated by the axial fan; (d) reduced sound generated by the axial fan assembly; (e) improved balancing of the axial fan assembly; (f) reduced blade flutter of the axial fan; and (g) increased fatigue life duration of the axial fan assembly.In the foregoing description and the following claims, reference is made to a number of terms having the following meaning.An element or step mentioned in the singular and preceded by the word "a / an" is to be understood as not excluding plural elements or steps unless such exclusion is expressly mentioned. Moreover, references to an "example implementation" or "one implementation" of the present disclosure are not to be understood as excluding the presence of other implementations that also include the recited features."Optional" means that the event or circumstance described below may or may not occur and that the description includes cases where the event occurs and cases where it does not occur.Approximating language as used herein in the specification and claims may be used to modify any quantitative representation that may vary permissibly without resulting in a change in the basic function to which it relates. Accordingly, a value modified by one or more terms such as "about", "approximately", and "substantially" is not limited to the exact value indicated. At least in some cases, the approximate formulation may correspond to the accuracy of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined or interchanged. Such regions are marked and include all subareas included therein unless the context or language indicates otherwise.Disjunctive terms such as "at least one of X, Y, or Z," unless expressly stated otherwise, are generally understood in the context such that an element, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Such disjunctional terms are intended to mean, and should not mean, that in certain embodiments, at least one of X, at least one of Y, or at least one of Z must be present. Moreover, unless expressly stated otherwise, conjunctival expressions such as "at least one of X, Y and Z" are to be understood as meaning X, Y, Z or any combination thereof, which includes at least "X, Y and / or Z".The systems and methods described herein are not limited to the specific embodiments described herein, but the components of the systems and / or steps of the methods may be used independently and separately from other components and / or steps described herein.Although certain features of various embodiments of the invention are shown in some drawings and not in others, this is for clarity only. In accordance with the principles of the invention, each feature of a drawing may be referenced and / or claimed in combination with each feature of another drawing.In this written description, the invention, including the best mode, is disclosed by way of example to enable one skilled in the art to practice the invention, including making and using any layers or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedUS 18 / 541,499

[0001]

Claims

An axial fan assembly, the axial fan assembly comprising: an axial fan comprising a hub and one or more blades extending radially from a center of the hub about which the axial fan rotates relative to a rotational axis, each of the one or more blades extending beyond a blade length to a free edge defining an outermost edge of the one or more blades; and an intermediate cover disposed radially outward of the hub and radially inward of the free edge of the one or more blades, the intermediate cover disposed proximate the free edge of the one or more blades to increase stability of the one or more blades.The axial fan assembly of claim 1, further comprising a plurality of blades downstream of the one or more blades of the axial fan, each of the plurality of blades comprising a leading edge, wherein the intermediate cover comprises an upper end disposed proximate the leading edge of the plurality of blades.The axial fan assembly of claim 2, wherein the upper end of the intermediate shroud is separated from the leading edge of the plurality of blades by a gap that is substantially equal to or greater than 0.05 inches.The axial fan assembly of claim 3, wherein the gap is substantially equal to or less than 1 inch.The axial fan assembly of any preceding claim, wherein the free edge of the one or more blades comprises a blade tip defining an extreme end of the one or more blades.The axial fan assembly of claim 5, wherein the intermediate cover is disposed proximate the blade tip of the one or more blades.The axial fan assembly of claim 6, wherein a distance between the intermediate cover and the blade tip of the one or more blades of the axial fan is between 10% and 40% of a distance between the blade tip of the one or more blades of the axial fan and the hub of the axial fan.The axial fan assembly of any of claims 6 or 7, wherein a distance between the intermediate cover and the hub of the axial fan is between 60% and 90% of a distance between the blade tip of the one or more blades of the axial fan and the hub of the axial fan.The axial fan assembly of any preceding claim, wherein at least one of a production flow rate of the axial fan and uniformity of flow generated by the axial fan is increased.The axial fan assembly of any preceding claim, wherein the hub comprises a sidewall extending substantially parallel to the axis of rotation, and wherein the intermediate cover extends substantially parallel to the sidewall of the hub.The axial fan assembly of any preceding claim, wherein the intermediate cover includes one or more shafts forming a substantially sinusoidal shape.The axial fan assembly of any preceding claim, wherein the intermediate cover extends through a leading edge of the one or more blades of the axial fan a lateral distance up to 0.5 inches behind the leading edge.The axial fan assembly of any preceding claim, wherein the intermediate shroud extends through a trailing edge of the one or more blades of the axial fan a lateral distance up to 1.5 inches behind the trailing edge.The axial fan assembly of any preceding claim, wherein at least one end of the intermediate cover has an elliptical shape.The axial fan assembly of any preceding claim, wherein the intermediate cover includes one or more balancing features to enable improved balancing of the axial fan assembly.A method of using an axial fan assembly, the method comprising: providing an axial fan comprising a hub and one or more blades extending radially from a center of the hub about which the axial fan rotates relative to a rotational axis, each of the one or more blades extending beyond a blade length to a free edge defining an outermost edge of the one or more blades; disposing an intermediate cover radially outward of the hub and radially inward of the free edge of the one or more blades, the intermediate cover disposed proximate the free edge of the one or more blades; and rotating the axial fan, the intermediate cover increasing stability of the one or more blades.The method of claim 16, further comprising providing a plurality of blades, each of the plurality of blades comprising a leading edge, wherein disposing the intermediate cover comprises positioning an upper end of the intermediate cover proximate the leading edge of the plurality of blades.The method of claim 17, wherein disposing the intermediate cover comprises positioning the top end of the intermediate cover a distance from the leading edge of the plurality of blades, the distance being at least one of substantially equal to 0.05 inches, between 0.05 inches and 1 inch, or substantially equal to 1 inch.The method of any of claims 16 to 18, wherein the free edge of the one or more blades comprises a blade tip defining an extreme end of the one or more blades, and wherein disposing the intermediate cover comprises positioning the intermediate cover proximate the blade tip of the one or more blades.The method of any of claims 16 to 19, wherein the intermediate cover includes one or more waves forming a substantially sinusoidal shape.

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