Patent Application
20230026923
Not Applicable.
Not Applicable.
Not Applicable.
This invention pertains to a blower fan assembly.
One aspect of the disclosure is a blower fan assembly comprising a scroll housing, a forward curved blower wheel, and a blower motor adapted to rotate the blower wheel about a blower wheel axis. The forward-curved blower wheel comprises a plurality of fan blades circumferentially spaced about the blower wheel axis. Each of the fan blades has a leading edge and a trailing edge. The blower wheel has an inner radius. The inner radius of the blower wheel is the radial distance between the blower wheel axis and the leading edge of each fan blade. The blower wheel has an outer radius. The outer radius of the blower wheel is the radial distance between the blower wheel axis and the trailing edge of each fan blade. The leading edge of each fan blade has a leading edge angle. The leading edge angle is the angle between a first tangent line and a first reference line. The first tangent line is a line tangent to the camber line at the leading edge. The first reference line intersects the leading edge and is perpendicular to a first radial line extending from the blower wheel axis to the leading edge. The first tangent line and the first reference line are in a plane perpendicular to the blower wheel axis. The trailing edge of each fan blade has a trailing edge angle. The trailing edge angle is the angle between a second tangent line and a second reference line. The second tangent line is tangent to the camber line at the trailing edge. The second reference line intersects the trailing edge and is perpendicular to a second radial line extending from the blower wheel axis to the trailing edge. The second tangent line and the second reference line are in a plane perpendicular to the blower wheel axis. The leading edge angle is at least 50° and not more than 80°. The trailing edge angle is at least 5.5° and not more than 18.5°. The outer radius is not more than 4 inches (101.6 mm). The blower wheel is within the scroll housing.
Another aspect of the disclosure is a blower fan assembly comprising a scroll housing, a forward curved blower wheel, and a blower motor adapted to rotate the blower wheel about a blower wheel axis. The scroll housing has a blower wall and opposite axial sides. The blower wall has a scroll profile as viewed in a plane perpendicular to the blower wheel axis. The blower wall extends axially from one of the axial sides to the other of the axial sides. The scroll profile of the blower wall extends circumferentially from a first scroll end to a second scroll end. The blower wall has a cut-off at the first scroll end. The scroll housing has a cut-off angle. The cut-off angle is an angle between a first radial scroll line extending from the blower wheel axis to the first scroll end and a second radial scroll line extending from the blower wheel axis to the second scroll end. The cut-off angle is 68°±10°. The blower wall has an exhaust wall portion extending generally straight from the second radial scroll line and an exhaust angle. The exhaust angle is the angle between the exhaust wall portion and an exhaust line. The exhaust line is perpendicular to the second radial scroll line and intersects the second scroll end. The exhaust angle is 5°±3°. The blower wall has an angle at cut-off. The angle at cut-off is the angle between a cut-off reference line and the cut-off. The cut-off reference line is perpendicular to the second radial scroll line and extends from the second radial scroll line through the cut-off. The angle at cut-off is 25°±5°. The blower wheel is within the scroll housing.
Another aspect of the disclosure is a scroll housing. The scroll housing has a blower wall and opposite axial sides. The blower wall has a scroll profile as viewed in a plane perpendicular to the blower wheel axis. The blower wall extends axially from one of the axial sides to the other of the axial sides. The scroll profile of the blower wall extends circumferentially from a first scroll end to a second scroll end. The blower wall has a cut-off at the first scroll end. The scroll housing has a cut-off angle. The cut-off angle is an angle between a first radial scroll line extending from the blower wheel axis to the first scroll end and a second radial scroll line extending from the blower wheel axis to the second scroll end. The cut-off angle is 68°±10°. The blower wall has an exhaust wall portion extending generally straight from the second radial scroll line and an exhaust angle. The exhaust angle is the angle between the exhaust wall portion and an exhaust line. The exhaust line is perpendicular to the second radial scroll line and intersects the second scroll end. The exhaust angle is 5°±3°. The blower wall has an angle at cut-off. The angle at cut-off is the angle between a cut-off reference line and the cut-off. The cut-off reference line is perpendicular to the second radial scroll line and extends from the second radial scroll line through the cut-off. The angle at cut-off is 25°±5°.
Another aspect of the disclosure is a forward-curved blower wheel. The forward-curved blower wheel comprises a plurality of fan blades circumferentially spaced about the blower wheel axis. Each of the fan blades has a leading edge and a trailing edge. The blower wheel has an inner radius. The inner radius of the blower wheel is the radial distance between the blower wheel axis and the leading edge of each fan blade. The blower wheel has an outer radius. The outer radius of the blower wheel is the radial distance between the blower wheel axis and the trailing edge of each fan blade. The leading edge of each fan blade has a leading edge angle. The leading edge angle is the angle between a first tangent line and a first reference line. The first tangent line is a line tangent to the camber line at the leading edge. The first reference line intersects the leading edge and is perpendicular to a first radial line extending from the blower wheel axis to the leading edge. The first tangent line and the first reference line are in a plane perpendicular to the blower wheel axis. The trailing edge of each fan blade has a trailing edge angle. The trailing edge angle is the angle between a second tangent line and a second reference line. The second tangent line is tangent to the camber line at the trailing edge. The second reference line intersects the trailing edge and is perpendicular to a second radial line extending from the blower wheel axis to the trailing edge. The second tangent line and the second reference line are in a plane perpendicular to the blower wheel axis. The leading edge angle is at least 50° and not more than 80°. The trailing edge angle is at least 5.5° and not more than 18.5°. The outer radius is not more than 4 inches (101.6 mm).
Further features and advantages, as well as the operation, are described in detail below with reference to the accompanying drawings.
Reference numerals in the written specification and in the figures indicate corresponding items.
An embodiment of a blower fan assembly, generally indicated by the reference number (20), is shown in
Referring to
The blower wheel has an inner radius (RI). The inner radius (RI) of the blower wheel (24) is the radial distance between the blower wheel axis (X) and the leading edge (30) of each fan blade (28). The inner radius (RI) is at least 2.3 inches, and the inner radius (RI) is preferably 83.82 mm (approximately 3.3 inches).
The blower wheel (24) has an outer radius (RO). The outer radius (RO) of the blower wheel (24) is the radial distance between the blower wheel axis (X) and the trailing edge (32) of each fan blade (28). The outer radius (RO) is not more than 4 inches (101.6 mm), and the outer radius (RO) is preferably 98 mm (approximately 3.86 inches).
The leading edge (30) of each fan blade (28) has a leading edge angle (θLE). The leading edge angle (θLE) is the angle between a first tangent line (LT1) and a first reference line (L1). The first tangent line (LT1) is a line tangent to a camber line (LCAMBER) at the leading edge (30). As used herein, camber line is the mean line of the blade profile. The first reference line (L1) intersects the leading edge (30) and is perpendicular to a first radial line (LR1) extending from the blower wheel axis (X) to the leading edge (30). The first tangent line (LT1) and the first reference line (L1) are in a plane perpendicular to the blower wheel axis (X). The leading edge angle (θLE) is at least 50° and not more than 80°. For example, in one embodiment the leading edge angle (θLE) may be 60°, while in another embodiment, the leading edge angle (θLE) may be 70°.
The trailing edge (32) of each fan blade (28) has a trailing edge angle (θTE). The trailing edge angle (θTE) is the angle between a second tangent line (LT2) and a second reference line (L2). The second tangent line (LT2) is tangent to the camber line (LCAMBER) at the trailing edge (32). The second reference line (L2) intersects the trailing edge (32) and is perpendicular to a second radial line (LR2) extending from the blower wheel axis (X) to the trailing edge (32). The second tangent line (LT2) and the second reference line (L2) are in a plane perpendicular to the blower wheel axis (X). The trailing edge angle (θTE) is at least 5.5° and not more than 18.5°. For example, in one embodiment the trailing edge angle (θTE) may be 6.5°, while in another embodiment, the trailing edge angle (θTE) may be 18.25°.
Each fan blade (28) has a stagger angle (θSA) and a chord line (LCHORD). The stagger angle (θSA) is the angle between the chord line (LCHORD) and a radial line (LR3) extending from the axis of rotation (X) and intersecting the leading edge (30). The stagger angle (θSA) is 30°±15°. For instance, the stagger angle (θSA) may be 30° in an embodiment.
The blower wheel (24) may further comprise a blower wheel inlet (34) and an internal cavity (36). The blower wheel inlet (34) is axially aligned with the fan axis (X). The internal cavity (36) is bounded by the blower wheel inlet (34) and the leading edges (30) of the fan blades (28).
The blower wheel inlet (34) may comprise a first blower wheel inlet (38), and the blower wheel (24) may further comprise a second blower wheel inlet (40). The internal cavity (36) is further bounded by the second blower wheel inlet (40).
The blower fan assembly (20) may further comprise a center disc (42). The center disc (42) is axially between and axially spaced from the first and second blower wheel inlets (38 and 40, respectively), and is at least partially within the blower wheel. Additionally, the internal cavity (36) may comprise a first internal cavity portion (44), and a second internal cavity portion (46). The first internal cavity portion (44) is between the first blower wheel inlet (38) and the center disc (42), and the second internal cavity portion (46) is between the second blower wheel inlet (40) and the center disc (42).
Referring to
The scroll housing (22) has a cut-off angle (θCO). The cut-off angle (θCO) is an angle between a first radial scroll line (LS1) extending from the blower wheel axis (X) to the first scroll end (54) and a second radial scroll line (LS2) extending from the blower wheel axis (X) to a second scroll end (56). The cut off angle (θCO) is 68°±10°, and more preferably 68°±5°.
The blower wall (48) has an exhaust wall portion (60) and an exhaust angle (θEX). The exhaust wall portion (60) extends generally straight from the second radial scroll line (LS2). The exhaust angle is the angle between the exhaust wall portion (60) and an exhaust line (LEX). The exhaust line (LEX) extends from the second scroll end (56) and is perpendicular to the second radial scroll line (LS2). The exhaust angle is 5°±3°, and may be 5°±1°.
The blower wall (48) has an angle at cut-off (θACO). The angle at cut-off (θACO) is the angle between a cut-off reference line (LCO) and the cut-off (58). The cut-off reference line (LCO) is perpendicular to the second radial scroll line (LS2) and extends from the second radial scroll line (LS2) through the cut-off (58). The angle at cut-off (θACO) is 25°±5°, and may be 25°±3°.
In operation, the blower motor (26) rotates the blower wheel (24) at 1400-1600 rpm with a flow rate between 500 and 1500 cubic feet per minute (CFM). The above-described characteristics of the scroll housing (22) and the blower wheel (24) enable the blower fan assembly (20) to have a static blower efficiency at least 15% higher than prior art blower fan assemblies of comparable size. Additionally, the present blower fan assembly (20) may be up to 4 dB(A) quieter than prior art blower fan assemblies of comparable size.
In view of the foregoing, it should be appreciated that the invention has several advantages over the prior art.
It should also be understood that when introducing elements of the present invention in the claims or in the above description of exemplary embodiments of the invention, the terms “comprising,” “including,” and “having” are intended to be open-ended and mean that there may be additional elements other than the listed elements. Additionally, the term “portion” should be construed as meaning some or all of the item or element that it qualifies. Moreover, use of identifiers such as first, second, and third should not be construed in a manner imposing any relative position or time sequence between limitations.
As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.
