US3799735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conveyor flights for rotary kiln
Assignee: FLSmidth and Co AS
•
Filing: 1972-01-05
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Granted: 1974-03-26
•
Expires: 1992-01-05
Abstract
Abstract A method for producing heat exchange between particles of raw materials and hot combustion gases in an inclined rotary kiln is disclosed. The kiln includes trough-shaped conveyor flights constructed to discharge the particles over the length of the kiln in the form of clouds of substantially parallel vertical curtains extending across the kiln at an acute angle to the axis of the kiln. The kiln can be used in a plant including means for collecting and returning the material carried out of the kiln.
Inventors
- 👤 F Jensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:06
CPC Classifications
F; F28; F28C; F28C3/00; F28C3/10; F28C3/12; F27; F27B; F27B7/00; F27B7/14; F27B7/16; F27B7/161
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
152 words
A method for producing heat exchange between particles of raw materials and hot combustion gases in an inclined rotary kiln comprising the steps of moving said particles down the kiln toward the hot zone thereof, alternately lifting and dropping said particles during their passage down the kiln to produce clouds of falling particles in the form of substantially parallel vertical curtains each extending across the kiln at an acute angle to the axis of the kiln to cover substantially the total cross-sectional area of the kiln and each having a sufficient density to relieve gases entering said curtains of suspended particles and to entrain new particles from the curtains to form gases supersaturated with particles, before reaching and during through the next curtain precipitating particles from the supersaturated gases, separating the particles suspended in the gases leaving the last curtain; and returning the particles separated from the last curtain to said kiln.
Claim 2
Independent Claim
152 words
A method for producing heat exchange between particles of raw materials and hot combustion gases in an inclined rotary kiln comprising the steps of moving said particles down the kiln toward the hot zone thereof, alternately lifting and dropping said particles during their passage down the kiln to produce clouds of falling particles in the form of substantially parallel vertical curtains each extending across the kiln at an acute angle to the axis of the kiln to cover substantially the total cross-sectional area of the kiln and each having a sufficient density to relieve gases entering said curtains of suspended particles and to entrain new particles from the curtains to form gases supersaturated with particles, before reaching and during through the next curtain precipitating particles from the supersaturated gases, separating the particles suspended in the gases leaving the last curtain; and returning the particles separated from the last curtain to said kiln.
Claim 3
Dependent Claim
26 words
A method according to claim 1 in which the material is cement raw meal which is formed into the transverse curtains while being preheated and calcined.
Claim 4
Dependent Claim
33 words
A method according to claim 2 in which the free flow of the material down the bottom of the kiln is checked several times in the preheating and calcining zones of the kiln.
Claim 5
Dependent Claim
108 words
A rotary kiln for producing heat exchange between particles of raw materials and combustion gases, said kiln comprising a plurality of trough-shaped conveyor flights extending helically along the inner wall of the kiln from the upper end over a length of the kiln at least equal to five times the internal diameter of the kiln, said conveyor flights being constructed to contain, lift and discharge sufficient amounts of material to produce clouds of falling particles in the form of substantially parallel vertical curtains each extending across the kiln at an acute angle to the axis of the kiln to cover substantially the total cross-sectional area of the kiln.
Claim 6
Dependent Claim
108 words
A rotary kiln for producing heat exchange between particles of raw materials and combustion gases, said kiln comprising a plurality of trough-shaped conveyor flights extending helically along the inner wall of the kiln from the upper end over a length of the kiln at least equal to five times the internal diameter of the kiln, said conveyor flights being constructed to contain, lift and discharge sufficient amounts of material to produce clouds of falling particles in the form of substantially parallel vertical curtains each extending across the kiln at an acute angle to the axis of the kiln to cover substantially the total cross-sectional area of the kiln.
Claim 7
Dependent Claim
23 words
A rotary kiln according to claim 4 including barriers, said barriers provided to stop the flow along some or all of the flights.
Claim 8
Dependent Claim
40 words
A rotary kiln according to claim 5 in which dam rings are provided in the zone in which the transverse curtains are formed to check the flow of the material along both the bottom of the kiln and the flights.
Claim 9
Dependent Claim
26 words
A rotary kiln according to claim 4 in which the flights form an angle of between 15* and 25* with the generatrix of the kiln tube.
Claim 10
Dependent Claim
21 words
A rotary kiln plant according to claim 4 further including means for collecting and returning material carried out of the kiln.
Claim 11
Dependent Claim
47 words
A rotary kiln plant according to claim 8 in which a single cyclone is provided to receive all the gases from the kiln and the material carried by them, and the material outlet of the cyclone is directly connected to a feed pipe for the raw material.
Claim 12
Dependent Claim
22 words
A rotary kiln plant according to claim 9 including an electrostatic precipitator and means for returning the dust precipitated to the kiln.
Claim 13
Dependent Claim
29 words
A rotary kiln plant according to claim 9 including means for introducing raw material collected from the hot gases into a riser pipe connecting the kiln to the cyclone.
References Cited (Backward Citations)
US1636467A
Cited
US2549787A
Cited
US2965366A
Cited
US3306237A
Cited
US3603569A
Cited
US3641683A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |