US3674903A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for reducing air infiltration into electric arc furnace during the charging and melting operation
Assignee: Lukens Inc
•
Filing: 1971-04-20
•
Granted: 1972-07-04
•
Expires: 1991-04-20
Abstract
Abstract An air curtain arrangement for the charging opening of an electric arc steelmaking furnace for restricting entry of air into the furnace, the air curtain apparatus being disposed above the opening and spaced sufficiently from the furnace wall to permit the door which normally covers the opening to be raised. An air screen is directed downwardly and a pair of side air flows are provided to screen the areas between the furnace wall and the air screen which is provided across the opening. Two further air flows are directed against the sides of the door, one on each side thereof for the purpose of screening these areas against incursion around the raised door of outside air into the furnace which is maintained at a pressure slightly less than atmospheric pressure during the door charging operation.
Inventors
- 👤 William W Bintzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:28
CPC Classifications
C; C21; C21C; C21C5/00; C21C5/52; C21C5/527; F; F27; F27D; F27D3/00; F27D3/18; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y10; Y10S; Y10S266/00; Y10S266/903
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
138 words
The combination of an air curtain for a steelmaking furnace which comprises an opening in said furnace; a door adapted to move vertically disposed in front of said opening; an air curtain housing mounted above said opening; lift means connected to said door for displacing it vertically in front of said opening to between said housing and said furnace above said door; a pair of air directing means included in said air curtain housing; a first of said air directing means directing a first curtain of air in front of said opening, the second of said air directing means directing a second curtain of air into the space between said housing and said door when said door is lifted to a position between said housing and said furnace; and blower means supplying air to said air directing means.
Claim 2
Dependent Claim
138 words
The combination of an air curtain for a steelmaking furnace which comprises an opening in said furnace; a door adapted to move vertically disposed in front of said opening; an air curtain housing mounted above said opening; lift means connected to said door for displacing it vertically in front of said opening to between said housing and said furnace above said door; a pair of air directing means included in said air curtain housing; a first of said air directing means directing a first curtain of air in front of said opening, the second of said air directing means directing a second curtain of air into the space between said housing and said door when said door is lifted to a position between said housing and said furnace; and blower means supplying air to said air directing means.
Claim 3
Dependent Claim
82 words
The combination of claim 1 where a further air curtain housing is provided, said further housing mounted above said opening between said furnace and said door when said door is lifted to a position between said first mentioned housing and said furnace, third air directing means included in said further housing directing a third curtain of air into the space between said furnace and said door when said door is lifted to a position between said first mentioned housing and said furnace.
Claim 4
Dependent Claim
39 words
A combination of claim 1 wherein further air directing means are provided to direct a pair of air curtains between the outer vertical edges of said first curtain of air and said furnace adjacent both sides of said opening.
Claim 5
Dependent Claim
33 words
The combination of claim 1 wherein said first air directing means comprising a nozzle extending below said first mentioned housing, the longer sides of said nozzle extending horizontally substantially parallel to said door.
Claim 6
Dependent Claim
22 words
The combination of claim 4 wherein a pair of radiation guards are provided on both of the longer sides of said nozzle.
Claim 7
Dependent Claim
30 words
The combination of claim 5 wherein said radiation guards are provided with heat expansion means whereby said guards are not warped by heat radiations from molten steel and molten slag.
Claim 8
Dependent Claim
18 words
The combination of claim 1 wherein said furnace contains molten steel having a temperature in excess of 2,800*F.
Claim 9
Dependent Claim
25 words
The combination of claim 7 wherein the gas contained in said furnace has a negative pressure relative to the concurrent atmospheric pressure surrounding said furnace.
Claim 10
Independent Claim
115 words
A method of reducing air infiltration from the surrounding atmosphere into an operating electric arc furnace when the furnace door is opened which comprises screening said opening by directing a downward air flow across the entire width of said opening, and with said furnace door being raised above said opening and spaced between the source of said downward air flow and said furnace, screening both sides of said door in its raised position by directing a pair of air flows against said door, one of said air flows screening space between said door and said furnace and the other of said air flows screening space between said door and the source of downward air flow.
Claim 11
Independent Claim
115 words
A method of reducing air infiltration from the surrounding atmosphere into an operating electric arc furnace when the furnace door is opened which comprises screening said opening by directing a downward air flow across the entire width of said opening, and with said furnace door being raised above said opening and spaced between the source of said downward air flow and said furnace, screening both sides of said door in its raised position by directing a pair of air flows against said door, one of said air flows screening space between said door and said furnace and the other of said air flows screening space between said door and the source of downward air flow.
Claim 12
Dependent Claim
30 words
The method of claim 9 wherein a further pair of downward air flows are directed adjacent the lateral limits of said first mentioned downward air flow and adjacent said furnace.
Claim 13
Dependent Claim
22 words
The method of claim 9 wherein said downward air flow is directed so as to be inclined outwardly relative to said furnace.
Claim 14
Independent Claim
92 words
A method for reducing air pollution from exhaust gases of an electric arc furnace while charging steelmaking material through an opening into the furnace during the steelmaking process which comprises establishing and maintaining gases in the interior of said electric arc furnace at a pressure less than the surrounding atmospheric pressure and screening said charging opening by directing an air flow across the entire width of said opening whereby the introduction of air into said furnace is minimized and the generation of fumes and dust from air so introduced is substantially eliminated.
Claim 15
Independent Claim
92 words
A method for reducing air pollution from exhaust gases of an electric arc furnace while charging steelmaking material through an opening into the furnace during the steelmaking process which comprises establishing and maintaining gases in the interior of said electric arc furnace at a pressure less than the surrounding atmospheric pressure and screening said charging opening by directing an air flow across the entire width of said opening whereby the introduction of air into said furnace is minimized and the generation of fumes and dust from air so introduced is substantially eliminated.
Claim 16
Dependent Claim
17 words
A method in accordance with claim 12 wherein said air flow is directed in a downwardly direction.
Claim 17
Dependent Claim
23 words
A method in accordance with claim 13 wherein said air flow is directed so as to be inclined outwardly relative to said opening.
Claim 18
Dependent Claim
26 words
A method in accordance with claim 13 wherein a pair of further air flows are directed downwardly between said furnace and said first mentioned air flow.
Claim 19
Dependent Claim
71 words
A method in accordance with claim 13 wherein the door for said opening is pulled upwardly relative to the position of said opening and two air flows are directed against the vertical sides of the door, one said air flow on each side of said sides being substantially parallel to the proximate furnace walls, whereby the introduction of air into the furnace from the vicinity of said wall is substantially restricted.
Claim 20
Dependent Claim
21 words
A method in accordance with claim 16 wherein the directions of said two air flows are inclined upwardly towards said sides.
Claim 21
Independent Claim
72 words
A method of reducing air infiltration from the surrounding atmosphere into an operating electric arc furnace which comprises screening the charging door of said furnace with a curtain of air to prevent significant leakage of atmospheric air into said furnace around said door, and at the same time exhausting said furnace to maintain the absolute pressure of the gas within said furnace less than that of the atmosphere immediately outside said furnace.
Claim 22
Independent Claim
72 words
A method of reducing air infiltration from the surrounding atmosphere into an operating electric arc furnace which comprises screening the charging door of said furnace with a curtain of air to prevent significant leakage of atmospheric air into said furnace around said door, and at the same time exhausting said furnace to maintain the absolute pressure of the gas within said furnace less than that of the atmosphere immediately outside said furnace.
Claim 23
Dependent Claim
13 words
The method of claim 18 wherein said difference is about 0.05 inches watergage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |