US3771946A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for carrying out endothermic processes in a shaft furnace
Assignee: Individual
•
Filing: 1971-05-17
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Granted: 1973-11-13
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Expires: 1991-05-17
Abstract
Abstract A process for calcining lime in a furnace or kiln having two spaced vertical shafts including each a preheating, a combustion and a cooling zone and joined together at the lower end of the combustion zone, comprising heating the material in the preheating zone, introducing a current of primary air into the top of one shaft to flow through the combustion zone into the other shaft upwardly and outwardly together with waste gas, introducing secondary air into one or both shafts in a counter flow direction from the bottom of the cooling zone, and feeding a fuel material into the combustion zone at more than one position so that a portion of the fuel material burns only with the secondary air.
Inventors
- 👤 H Hofer
- 👤 A Schmid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:00
CPC Classifications
F; F27; F27B; F27B1/00; F27B1/02; C; C04; C04B; C04B2/00; C04B2/10; C04B2/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
208 words
A process for an endothermic reaction in a furnace or kiln having first and second vertical shafts with each shaft having, from top to bottom, a preheating zone, a combustion zone and a cooling zone, means for joining the two shafts and providing communication therebetween at the lower regions of the combustion zones and fuel gas supply means located in each shaft and in the means for joining the shafts, which process comprises: a. Introducing the materials required to undergo the reaction down into the tops of the shafts, b. preheating the materials in the preheating zones of the shafts, c. introducing a source of primary air down into the top of the first shaft concurrently with the materials being fed therein, d. feeding fuel gas into the combustion zone of the first shaft from the fuel gas supply means located therein such that a portion of the fuel gas is caused to enter into the second shaft through the means joining the two shafts, e. introducing a source of secondary air up into the bottom of at least the second shaft countercurrently against the materials being fed therein such that only the secondary air effects combustion of the portion of the fuel gas entering the second shaft.
Claim 2
Dependent Claim
208 words
A process for an endothermic reaction in a furnace or kiln having first and second vertical shafts with each shaft having, from top to bottom, a preheating zone, a combustion zone and a cooling zone, means for joining the two shafts and providing communication therebetween at the lower regions of the combustion zones and fuel gas supply means located in each shaft and in the means for joining the shafts, which process comprises: a. Introducing the materials required to undergo the reaction down into the tops of the shafts, b. preheating the materials in the preheating zones of the shafts, c. introducing a source of primary air down into the top of the first shaft concurrently with the materials being fed therein, d. feeding fuel gas into the combustion zone of the first shaft from the fuel gas supply means located therein such that a portion of the fuel gas is caused to enter into the second shaft through the means joining the two shafts, e. introducing a source of secondary air up into the bottom of at least the second shaft countercurrently against the materials being fed therein such that only the secondary air effects combustion of the portion of the fuel gas entering the second shaft.
Claim 3
Dependent Claim
25 words
The process according to claim 1 wherein the steps of the process are reversed in alternate cycles with respect to the first and second shafts.
Claim 4
Dependent Claim
32 words
The process according to claim 1 wherein the fuel gas is fed into the combustion zone of the first shaft from two positions located at the upper region of the combustion zone.
Claim 5
Dependent Claim
30 words
The process according to claim 3 wherein the fuel to primary air ratios at the two positions are above 1.0 for one position and below 1.0 for the other position.
Claim 6
Dependent Claim
26 words
The process according to claim 1 further including supplying fuel gas into the means for joining the shafts from the fuel gas supply means located therein.
Claim 7
Dependent Claim
29 words
The process of claim 1 wherein the means joining the two shafts together includes at least two by-pass ducts for effecting lateral transfer of gases between the two shafts.
References Cited (Backward Citations)
US3074706A
Cited
FR1454858A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |