US5022331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for introducing combustion air into a furnace
Assignee: Ahlstrom Corp
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Filing: 1990-04-06
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Granted: 1991-06-11
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Expires: 2010-04-06
Abstract
Abstract A method and apparatus for introducing combustion air in the form of air jets into a furnace (2) of, for example, a soda recovery boiler. Combustion air is introduced through air ports (12), arranged substantially at the same level (10), in air jets (13) of at least two sizes. Air ports in the walls (4) of the furnace are dimensioned in different sizes such that their hydraulic diameters increase from the corners of the furnace towards the centers of the furnace walls, whereby the degree of penetration of the respective air jets flowing through the air ports increases. The penetration of the air jets in maintained constant at different loading conditions.
Inventors
- 👤 Liisa I. Simonen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:33
CPC Classifications
F; F23; F23L; F23L9/00; F23G; F23G7/00; F23G7/04
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
89 words
A method of introducing combustion air in air jet form to a furnace having a plurality of walls from a plurality of air ports arranged at a substantially similar level in different walls of the furnace, comprising the steps of: introducing combustion air into the furnace in air jet form from at least two opposing furnace walls, said jets having at least two different sizes such that penetration of the air jets increases from corners of the furnace towards centers of the said at least two opposing furnace walls.
Claim 2
Independent Claim
89 words
A method of introducing combustion air in air jet form to a furnace having a plurality of walls from a plurality of air ports arranged at a substantially similar level in different walls of the furnace, comprising the steps of: introducing combustion air into the furnace in air jet form from at least two opposing furnace walls, said jets having at least two different sizes such that penetration of the air jets increases from corners of the furnace towards centers of the said at least two opposing furnace walls.
Claim 3
Dependent Claim
47 words
A method in accordance with claim 1, wherein combustion air is introduced from four walls of the furnace in air jets of different sizes such that penetration of the air jets increases from the corners of the furnace towards the center of each of said four walls.
Claim 4
Dependent Claim
89 words
A method in accordance with claim 1, and including the step of maintaining the penetration of the air jets substantially constant at varying loading conditions according to the formula L.sub.p =k×D.sub.n ×V.sub.n /V.sub.f (T.sub.f /T.sub.n)0.5 where Lp=penetration; Dn=hydraulic diameter, and Vn=air flow rate, by adjusting one or more of the hydraulic diameter of the air ports, the air flow rate in the air ports, and the temperature of the inlet air so that the air jets cover substantially the entire cross-sectional area of the furnace at different loading conditions.
Claim 5
Dependent Claim
45 words
A method in accordance with claim 1, wherein the furnace is a soda recovery boiler, and wherein the method includes the step of introducing secondary air into the boiler by air jets, and maintaining penetration of said air jets substantially constant at different loading conditions.
Claim 6
Dependent Claim
24 words
A method in accordance with claim 2, wherein the air jets form an envelope-shaped air supply profile over the cross-sectional area of the furnace.
Claim 7
Dependent Claim
18 words
A method in accordance with claim 1, wherein the penetration of the air jets is controlled by dampers.
Claim 8
Dependent Claim
24 words
A method in accordance with claim 6, wherein the penetration of air jets is controlled in groups by dampers arranged on a main shaft.
Claim 9
Dependent Claim
27 words
A method in accordance with claim 1, wherein the penetration of air jets is controlled by adjusting air pressure in wind boxes supplying air to said ports.
Claim 10
Dependent Claim
59 words
Apparatus for supplying combustion air to a furnace, the furnace having at least four walls, each of which is provided with a plurality of adjacent air ports in communication with a supply of air, said air ports being configured such that hydraulic diameters of said ports increase from corners of the furnace towards center portions of said furnace walls.
Claim 11
Dependent Claim
59 words
Apparatus for supplying combustion air to a furnace, the furnace having at least four walls, each of which is provided with a plurality of adjacent air ports in communication with a supply of air, said air ports being configured such that hydraulic diameters of said ports increase from corners of the furnace towards center portions of said furnace walls.
Claim 12
Dependent Claim
28 words
Apparatus in accordance with claim 9, wherein cross-sectional areas of said air ports increase from the corners of the furnace towards said center portions of said furnace walls.
Claim 13
Dependent Claim
67 words
Apparatus in accordance with claim 9, wherein two or more small air ports are located within effective range of each other in the center portion of at least one of said furnace walls in such a way that the combined hydraulic diameter of said two or more air ports is greater than the hydraulic diameter of individual air ports arranged close to the corners of the furnace.
Claim 14
Dependent Claim
28 words
Apparatus in accordance with claim 9, wherein the distance between the air ports diminishes from said center portions of said furnace walls towards said corners of the furnace.
Claim 15
Dependent Claim
20 words
Apparatus in accordance with claim 9, wherein said apparatus includes means for introducing combustion air to a soda recovery boiler.
Claim 16
Dependent Claim
19 words
Apparatus in accordance with claim 13, and further including means for introducing secondary air to the soda recovery boiler.
Claim 17
Dependent Claim
19 words
Apparatus in accordance with claim 9, wherein said apparatus includes means for introducing combustion air to a grate furnace.
Claim 18
Dependent Claim
29 words
Apparatus in accordance with claim 9, wherein dampers are arranged in the air ports so as to control the inlet pressure of the air being introduced to the furnace.
Claim 19
Dependent Claim
26 words
Apparatus in accordance with claim 16, wherein dampers are connected in groups on a main shaft such that said groups of dampers may be adjusted substantially.
References Cited (Backward Citations)
US3413936A
Cited
US4823710A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |