US4900228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Centrifugal fan with variably cambered blades
Assignee: Bosch Automotive Motor Systems Corp
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Filing: 1989-02-14
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Granted: 1990-02-13
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Expires: 2009-02-14
Abstract
Abstract Boundary layer separation in a rearwardly skewed centrifugal impeller can be better controlled by designing the impeller blades with an "S" camber, i.e., with rearward curved radially extending blades in a centrifugal blower. The blades have a positive camber at a radially inward region and a negative camber at a radially outward region of the blade.
Inventors
- 👤 Martin G. Yapp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:53
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/66; F04D29/68; F04D29/681; F04D29/26; F04D29/28; F04D29/281; F04D29/282; F04D29/30; F04D29/40; F04D29/42; F04D29/44; F04D29/441; F04D29/444; F05; F05D; F05D2250/00; F05D2250/50; F05D2250/52
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
78 words
A centrifugal blower comprising an impeller mounted to rotate on an axis, said impeller comprising a plurality of rearwardly curved, radially extending blades, said blades being characterized in that: (a) the blades have a positive camber at a radially inwardly region of the blade, said positive camber being 2-5% of the blade chord; (b) the blades have a negative camber at a radically outward region of the blade; whereby boundary layer separation is controlled to improve blower efficiency.
Claim 2
Dependent Claim
78 words
A centrifugal blower comprising an impeller mounted to rotate on an axis, said impeller comprising a plurality of rearwardly curved, radially extending blades, said blades being characterized in that: (a) the blades have a positive camber at a radially inwardly region of the blade, said positive camber being 2-5% of the blade chord; (b) the blades have a negative camber at a radically outward region of the blade; whereby boundary layer separation is controlled to improve blower efficiency.
Claim 3
Dependent Claim
82 words
The centrifugal blower comprising an impeller mounted to rotate on an axis, said impeller comprising a plurality of rearwardly curved, radially extending blades, said blades being characterized in that: (a) the blades have a positive camber at a radially inwardly region of the blade; (b) the blades have a negative camber at a radially outward region of the blade, said negative camber being no more than about 0.25-3% of the blade chord; whereby boundary layer separation is controlled to improve blower efficiency.
Claim 4
Dependent Claim
82 words
The centrifugal blower comprising an impeller mounted to rotate on an axis, said impeller comprising a plurality of rearwardly curved, radially extending blades, said blades being characterized in that: (a) the blades have a positive camber at a radially inwardly region of the blade; (b) the blades have a negative camber at a radially outward region of the blade, said negative camber being no more than about 0.25-3% of the blade chord; whereby boundary layer separation is controlled to improve blower efficiency.
Claim 5
Dependent Claim
48 words
A centrifugal blower comprising a set of primary blades characterized according to claim 1 or claim 2, and a set of secondary blades, each of said secondary blades being positioned between a pair of said primary blades, said primary blades extending radially inwardly further than said secondary blades.
Claim 6
Dependent Claim
35 words
The centrifugal blower of claim 3 in which the secondary blades have a positive camber at a radially inward portion of the blade, and a negative camber at a radially outward portion of the blade.
Claim 7
Dependent Claim
27 words
The centrifugal blower of claim 1 or claim 2 in which the maximum positive camber occurs at a blade radius of 20-30% of the total blade length.
Claim 8
Dependent Claim
27 words
The centrifugal blower of claim 1 or claim 2 in which the maximum negative camber occurs at a blade radius of 70-80% of the total blade length.
Claim 9
Dependent Claim
23 words
The centrifugal blower of claim 1 or claim 2 wherein the blower inlet area at least 20% less than the blower outlet area.
Claim 10
Dependent Claim
21 words
The centrifugal blower of claim 1 or claim 2 wherein the blades are two-dimensional, and they sweep out a three-dimensional solid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-12 | 1993-08-14 | 1994-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-12 | 1997-08-14 | 1998-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-12 | 2001-08-14 | 2002-02-13 | $7700.00 | Window Closed / Lapsed |