Fluid reaction surfaces (i.e. – impellers) – Specific working member mount – Distally supported on radial arm
Reexamination Certificate
2000-04-21
2002-09-10
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Specific working member mount
Distally supported on radial arm
C416S22300B, C416SDIG002, C416SDIG005
Reexamination Certificate
active
06447251
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a fan blade shaped to reduce noise during operation thereof.
2. Description of the Prior Art
A typical fan assembly for the application of condenser cooling in both residential and commercial air conditioning systems consists of a hub, a multi-wing spider, and multi blades, which could be 2, 3, or 4 blades. Each spider wing is attached with a blade through riveting or spot welding or other mechanical means. In a typical condenser cooling application, the fan is directly driven by a motor to draw airflow through the condenser coils to achieve cooling effect. The current art of condenser fan assembly implements rectangular blade shapes. These fans will generate sufficient air to meet varied cooling needs when they are pitched properly, however, they also radiate high levels of noise during operation.
In a typical condenser cooling application, the upstream air flow of a rotating fan is partially distorted due to the blockage of compressor, controlling panels, etc. As a result of it, tonal and broadband noise will be generated by a rotating blade leading edge cutting through the flow distortion, i.e. turbulence. Each small segment of the leading edge along the radial direction acts as a noise radiator.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a unique and effective blade for a fan assembly which produces sufficient air for cooling purposes with low noise level.
The fan blade is formed from a flat blank bent to a desired shape to form the fan blade. The fan blade has a front side, a rear side, an inner attachment portion, an outer edge, a curved leading edge and a curved trailing edge. The outer edge defines an arc between a forward position and a rearward position. The leading edge extends outward and intercepts the arc of the outer edge at the forward position and the trailing edge extends outward to the rearward position. An angle &agr;
L
is formed by a straight line having a length equal to R
L
extending from a given axis coinciding with the axis of the fan to the forward position and a line extending from said given axis to a first position on the leading edge and having a length equal to about 0.5R
L
wherein the angle &agr;
L
is equal to at least 35 degrees.
In a another aspect, the ratio of H
L
/L
L
is larger than about 0.10 but less than about 0.20, wherein L
L
is the length of a straight line from the first position to the forward position and H
L
is the maximum distance from L
L
to the leading edge as measured from a straight line perpendicular to L
L
and extending to the leading edge.
In a further aspect the angle &agr;
T
is at least 30 degrees but less than 40 degrees wherein &agr;
T
is formed by a line having a length equal to R
T
extending from said given axis to the rearward position and a line extending from said given axis to a second position the trailing edge and having a length equal to about 0.5R
T
.
In addition, the ratio H
T
/L
T
is larger than about 0.10 but less than 0.20, wherein L
T
is equal to the length of a straight line from the second position to the rearward position and H
T
is equal to the maximum distance from L
T
to the trailing edge as measured from a straight line perpendicular to L
T
and extending to the trailing edge.
REFERENCES:
patent: 4063852 (1977-12-01), O'Connor
patent: 4358245 (1982-11-01), Gray
patent: 4548548 (1985-10-01), Gray
patent: 4569631 (1986-02-01), Gray
patent: 4569632 (1986-02-01), Gray
patent: 4840541 (1989-06-01), Sakane et al.
patent: 4900228 (1990-02-01), Yapp
patent: 4917572 (1990-04-01), Van Houten
patent: 4946348 (1990-08-01), Yapp
patent: 4971520 (1990-11-01), Van Houten
patent: 5000660 (1991-03-01), Van Houten et al.
patent: 5064345 (1991-11-01), Kimball
patent: 5151014 (1992-09-01), Greenwald et al.
patent: 5156524 (1992-10-01), Forni
patent: 5221187 (1993-06-01), Lorea et al.
patent: 5297931 (1994-03-01), Yapp et al.
patent: 5342167 (1994-08-01), Rosseau
patent: 5423660 (1995-06-01), Sortor
patent: 5489186 (1996-02-01), Yapp et al.
patent: 5616004 (1997-04-01), Alizadeh
patent: 5769607 (1998-06-01), Neely et al.
“Smart' Housewares Highlights” published inAppliance Manufacturer, pp. 44-45, Mar. 2000.
“Advanced Technologies, Low Noise Fan, ‘Extra Fan’, Newly Developed”, A &R News, pp. 86-87, Jan./Feb. 1986.
Look Edward K.
McAleenan James M
Michael & Best & Friedrich LLP
Revcor, Inc.
LandOfFree
Fan blade does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fan blade, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fan blade will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2828054