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US4406618A
Expired / Lapsed
US
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Method of operating continuous heat treatment furnace for metal strip coils
Assignee: JFE Steel Corp
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Filing: 1981-12-17
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Granted: 1983-09-27
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Expires: 2001-12-17
Abstract
Abstract A method of operating a continuous heat treatment furnace for metal strip coils includes steps of enclosing them in muffles in the furnace supplied with an atmosphere gas containing a combustible gas such as hydrogen and feeding the muffles into and through the furnace having therein heating, soaking and cooling zones. According to the disclosed method, at least part of the heating and soaking zones is heated by direct firing heating with a fluid fuel with excess air and combustible gas leaked from the muffles into the furnace is burnt in the furnace with the aid of the excess air. Combustible gas leaked from the muffles into the cooling zone is diluted with air forced into the cooling zone to make the combustible gas incombustible and thereafter to exhaust it out of the furnace, thereby eliminating ignition means for the combustible gas in the furnace and particular precaution for preventing an ignition failure.
Inventors
- 👤 Kimio Maeyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:44
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/52; C21D9/54; C21D1/00; C21D1/34; C21D1/52; C21D1/74
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
153 words
In a method of operating a continuous heat treatment furnace, which furnace is divided by an intermediate door into heating, soaking and cooling zones, said method including steps of enclosing metal coils, which have been wound after being rolled, in muffles, and supplying the muffles with an atmosphere gas containing hydrogen gas, and feeding the muffles into and through the furnace so as to subject said coils to heating, soaking and cooling, the improvement which comprises heating at least part of said heating and soaking zones by direct firing-heating with a fluid fuel with excess air, burning in the furnace with the aid of said excess air combustible gas leaked from the muffles into the furnace, supplying an amount of air into said cooling zone so as to dilute combustible gas leaked from the muffles into said cooling zone and render it incombustible, and exhausting thereafter the incombustible gas out of the furnace.
Claim 2
Dependent Claim
153 words
In a method of operating a continuous heat treatment furnace, which furnace is divided by an intermediate door into heating, soaking and cooling zones, said method including steps of enclosing metal coils, which have been wound after being rolled, in muffles, and supplying the muffles with an atmosphere gas containing hydrogen gas, and feeding the muffles into and through the furnace so as to subject said coils to heating, soaking and cooling, the improvement which comprises heating at least part of said heating and soaking zones by direct firing-heating with a fluid fuel with excess air, burning in the furnace with the aid of said excess air combustible gas leaked from the muffles into the furnace, supplying an amount of air into said cooling zone so as to dilute combustible gas leaked from the muffles into said cooling zone and render it incombustible, and exhausting thereafter the incombustible gas out of the furnace.
Claim 3
Dependent Claim
29 words
An improved method as set forth in claim 1, wherein all said heating and soaking zones are heated by direct firing heating with the fluid fuel with excess air.
Claim 4
Dependent Claim
32 words
An improved method as set forth in claim 1, wherein an earlier half of the heating and soaking zones is heated by direct firing heating with the fluid fuel with excess air.
Claim 5
Dependent Claim
49 words
An improved method as set forth in claim 1, wherein in a zone subjected to an indirect heating other than the zone subjected to the direct firing heating, the combustible gas leaked from said muffles into said furnace is burnt with the aid of air forced into said furnace.
Claim 6
Dependent Claim
41 words
An improved method as set forth in claim 1, including burners with coke gas or heavy oil and electric heaters, wherein the heating step comprises effecting said direct firing-heating by said burners and carrying out other heating by said electric heaters.
References Cited (Backward Citations)
US2504810A
Cited
US3836320A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-26 | 1987-03-28 | 1987-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-26 | 1991-03-28 | 1991-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-26 | 1995-03-28 | 1995-09-27 | $7700.00 | Window Closed / Lapsed |