US3852026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of heating goods and a heating furnace
Assignee: Granges Engineering AB
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Filing: 1973-11-01
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Granted: 1974-12-03
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Expires: 1993-11-01
Abstract
Abstract A method and apparatus for use when heating or heat treating goods whose surfaces tend to react chemically with the surrounding atmosphere when subjected to heat. There is used a furnace which is heated without the combustion of fuel in the actual furnace space thereof. A controlled furnace atmosphere suitable for the material in question is maintained by supplying the furnace substantially continuously with a gas having a controlled composition. The goods are fed into and out of the furnace through at least one gas-flushed lock-type feed valve. The gas used to maintain the controlled atmosphere in the furnace is passed substantially continuously from the furnace to a gas storage device, from which it is passed intermittently to the feed valve to flush the same. The gas passed from the furnace to the storage device is compressed during its passage thereto and the feed valve is preferably evacuated prior to being flushed with said gas.
Inventors
- 👤 F Johansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:24
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/74
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
125 words
A method for the heating of material in a furnace of the type which is heated without combusting fuel in the furnace space itself and having at least one gas-flushed lock-type feed valve for charging and discharging the furnace, which material tends to react chemically with the surrounding atmosphere when subjected to heat, said method comprising maintaining in the furnace a controlled atmosphere suitable for the material being treated by supplying at least substantially constantly thereto a gas having a controlled composition, passing the gas used for maintaining the controlled atmosphere in the furnace at least substantially continuously from said furnace, storing said gas externally of the furnace in a magazine, and passing such stored gas intermittently to the feed valve for flushing the same.
Claim 2
Independent Claim
125 words
A method for the heating of material in a furnace of the type which is heated without combusting fuel in the furnace space itself and having at least one gas-flushed lock-type feed valve for charging and discharging the furnace, which material tends to react chemically with the surrounding atmosphere when subjected to heat, said method comprising maintaining in the furnace a controlled atmosphere suitable for the material being treated by supplying at least substantially constantly thereto a gas having a controlled composition, passing the gas used for maintaining the controlled atmosphere in the furnace at least substantially continuously from said furnace, storing said gas externally of the furnace in a magazine, and passing such stored gas intermittently to the feed valve for flushing the same.
Claim 3
Dependent Claim
20 words
A method according to claim 1 comprising compressing the gas removed from the furnace during its passage to the magazine.
Claim 4
Dependent Claim
16 words
A method according to claim 1 comprising evacuating the feed valve prior to flushing the same.
Claim 5
Dependent Claim
44 words
A method according to claim 1 further comprising flushing the feed valve with a second, inexpensive gas having a composition less deleterious to the material being treated than air, prior to flushing the valve with the said gas which is removed from the furnace.
Claim 6
Dependent Claim
99 words
A furnace system for heating material whose surface tends to react chemically with the surrounding atmosphere when subjected to heat, said system comprising a furnace including at least one gas-flushed lock-type feed valve for locking the material into and out of the furnace, means for controllably and substantially continuously supplying gas to said furnace and means for controllably and intermittently flushing the feed valve with gas, a gas magazine, means for substantially continuously passing gas from the furnace to said gas magazine and means for intermittently passing gas from the magazine to the feed valve to flush the same.
Claim 7
Dependent Claim
99 words
A furnace system for heating material whose surface tends to react chemically with the surrounding atmosphere when subjected to heat, said system comprising a furnace including at least one gas-flushed lock-type feed valve for locking the material into and out of the furnace, means for controllably and substantially continuously supplying gas to said furnace and means for controllably and intermittently flushing the feed valve with gas, a gas magazine, means for substantially continuously passing gas from the furnace to said gas magazine and means for intermittently passing gas from the magazine to the feed valve to flush the same.
Claim 8
Dependent Claim
33 words
A furnace system according to claim 5 further comprising means for compressing the gas removed from the furnace before introduction into said magazine, said magazine being in the form of a pressure vessel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |