This invention relates to a partitioned scroll diffuser, designed to efficiently provide multiple flow paths from a single centrifugal impeller.
One of the challenges for a designer of centrifugal blowers is to provide a scroll diffuser which efficiently converts velocity pressure to static pressure and at the same time aligns discharge flow accurately with the system flow paths required in a particular application of the blower. Efficient alignment of the discharge flow with the required system flow paths is essential in achieving the desired performance in a small package with low noise characteristics.
In certain applications, aligning the discharge flow from the scroll diffuser requires multiple discharges or a “high aspect ratio” single discharge. To date, one of two scroll housing configurations has been employed. The first is a multiple guide vane arrangement in the scroll diffuser as illustrated in
A general object of the present invention is to provide an improved scroll diffuser which overcomes the disadvantages of the aforesaid scroll diffusers, this result being achieved with a single centrifugal impeller.
In accordance with the present invention, at least one partition extending substantially in a radial plane is provided within the scroll diffuser of a centrifugal blower and has an inner opening receiving and having its edge in close proximity with the periphery of the centrifugal impeller. The partition serves to divide the scroll diffuser interior into at least two discrete axially adjacent flows for the discharge of air from the scroll section. More specifically, the scroll section of the impeller assembly is divided into at least two discrete scroll sub-sections in axially adjacent relationship and associated respectively with said at least two axially adjacent flows. The scroll sub-sections may provide for discharge openings which are axially and/or angularly displaced or the scroll sub-sections may be axially configured or displaced relative to each other to provide a common axially aligned discharge opening of increased length. Each scroll sub-section can be designed with its own expansion rate as required by discharge flow requirements and the scroll sub-section cut-offs can be rotated through an infinite number of angular positions while maintaining efficient impeller performance for each sub-section flow. It should be noted that prior art configurations require that scroll cut-offs be 180° apart to achieve reasonable efficiency in the absence of a vane diffuser as in
The design concept may be employed in any centrifugal blower assembly including but not limited to a forward curved impeller blade type, a backward inclined impeller blade, and a backward curved impeller blade. Plastic, metal or other construction is also accommodated. The number of radial plane partitions in the diffuser may vary as required. The axial width of each flow channel may also vary as well as the diffuser radial expansion angle and/or rate of expansion.
Benefits to the designer include allowing for variations in size and position of each housing discharge opening as the system application may require. Further, each scroll diffuser section may be designed to optimize the flow and pressure characteristics of the particular system flow paths involved. Benefits to the purchaser of the improved blower with partitioned scroll diffuser include a simple design versus multiple motorized impellers. The single impeller approach helps to reduce noise generation, lower power consumption, minimize space use, and increase reliability.
a is a schematic view of a prior art centrifugal blower with vanes provided in the diffuser resulting in a broad band discharge flow equal to approximately the diameter of the impeller.
b is a prior art schematic showing a centrifugal blower assembly provided with vanes resulting in a broad band discharge approximating twice the diameter of the impeller.
c is a further prior art schematic showing a centrifugal blower assembly with outlet vanes resulting in a diameter approximating three diameters of an impeller wheel.
a is a prior art schematic showing a centrifugal blower having discharge openings 180° opposed.
b is a further prior art schematic showing a vane diffuser with multiple discharge flow paths.
a through 2b illustrate various prior art designs employed in providing broad band and other discharge flow patterns primarily through the use of a plurality of vanes mounted in the scroll diffuser outlet section.
Referring particularly to
In accordance with the invention, the sub-sections 18 and 20 of the scroll are separated by the partition 22 and as illustrated in
From the foregoing it will be seen that the scroll sub-sections may vary in axial dimension, radial dimension and the sections may also be bodily displaced axially relative to each other to provide an aligned elongated opening having a common centerline as in
In
This is a continuation application of U.S. patent application Ser. No. 10/080,200 filed on Feb. 19, 2002 and entitled CENTRIFUGAL BLOWER WITH PARTITIONED SCROLL DIFFUSER, abandoned, which itself claims priority from U.S. Provisional Application 60/270,932 filed on Feb. 26, 2001 and entitled CENTRIFUGAL BLOWER WITH PARTITIONED SCROLL DIFFUSER, the contents of which being incorporated herein in their entirety.
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Number | Date | Country | |
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20110280748 A1 | Nov 2011 | US |
Number | Date | Country | |
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60270932 | Feb 2001 | US |
Number | Date | Country | |
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Parent | 10080200 | Feb 2002 | US |
Child | 12100063 | US |