US3814538A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air inlet throat for fans
Assignee: Svenska Flaktfabriken AB
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Filing: 1972-08-21
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Granted: 1974-06-04
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Expires: 1992-08-21
Abstract
Abstract A frame for the inlet of a fan having a fan wheel of either the axial flow or radial flow type, wherein the frame comprises an outer hollow cylindrical ring facing the inlet, an inner ring of smaller diameter facing the fan wheel and an abrupt transition between the rings provided by an annular flange. The ratio of the diameters of the inner and outer rings is within a critical range and is related to the length of the rings so that the air flow into the fan wheel generates a toroidal whirling and tumbling of the flow in the corner between the outer ring and the annular flange.
Inventors
- 👤 L Sjoqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:05
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/40; F04D29/52; F04D29/54; F04D29/541; F04D29/545; F04D29/547; F04D29/403
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
246 words
An air inlet throat for fans with a fan wheel for the transport of a gaseous medium, which comprises a frame surrounding the air inlet, said frame consisting of at least two hollow cylindrical rings of a certain width and of different diameters and arranged close to each other and having a decreasing cross section area for the gaseous medium in the flow direction of same, the fan wheel being located coaxial with and adjacent the ring having the smaller diameter, the ring of the greater diameter being located adjacent the inlet passage for the gaseous medium, the rings being mutually joined in pairs by means of an annuLar flange perpendicular to the axis of the rings, thereby creating an abrupt diminishing cross section area for the flowing medium owing to that the outer and inner diameters of said annular flange substantially correspond respectively to the diameters of the greater ring and of said smaller ring, said abrupt diminishing cross section area being arranged to create in the medium flowing into said inlet a toroid-like part of said gaseous medium whirling and tumbling around against said annular flange, the depth (L) of the two rings - measured in the flow direction of the gaseous medium - and the diameters D1 (the smaller one) and D2 the larger one) of said rings being such that: (0.3D2/D1 - 0.3) < L/D1 < (2.25D2/D1 - 2.45) and the two rings having such sizes that 1.13 < D2/D1 < 1.3
Claim 2
Dependent Claim
246 words
An air inlet throat for fans with a fan wheel for the transport of a gaseous medium, which comprises a frame surrounding the air inlet, said frame consisting of at least two hollow cylindrical rings of a certain width and of different diameters and arranged close to each other and having a decreasing cross section area for the gaseous medium in the flow direction of same, the fan wheel being located coaxial with and adjacent the ring having the smaller diameter, the ring of the greater diameter being located adjacent the inlet passage for the gaseous medium, the rings being mutually joined in pairs by means of an annuLar flange perpendicular to the axis of the rings, thereby creating an abrupt diminishing cross section area for the flowing medium owing to that the outer and inner diameters of said annular flange substantially correspond respectively to the diameters of the greater ring and of said smaller ring, said abrupt diminishing cross section area being arranged to create in the medium flowing into said inlet a toroid-like part of said gaseous medium whirling and tumbling around against said annular flange, the depth (L) of the two rings - measured in the flow direction of the gaseous medium - and the diameters D1 (the smaller one) and D2 the larger one) of said rings being such that: (0.3D2/D1 - 0.3) < L/D1 < (2.25D2/D1 - 2.45) and the two rings having such sizes that 1.13 < D2/D1 < 1.3
Claim 3
Dependent Claim
27 words
An air inlet throat in accordance with claim 1 for an axial flow fan, wherein the fan wheel is located in the ring of the smaller diameter.
Claim 4
Dependent Claim
44 words
An air inlet throat in accordance with claim 1 for a radial flow fan, wherein the air inlet of the fan wheel is located adjacent said smaller ring with an axial clearance between the ring of the smaller diameter and the fan wheel inlet.
Claim 5
Dependent Claim
35 words
An air inlet throat in accordance with claim 1 for a radial flow fan, wherein the ring of the smaller diameter projects into the inlet of the fan wheel with a radial clearance between them.
References Cited (Backward Citations)
US1465097A
Cited
GB376647A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |