Patent US3785765A successfully refreshed from Google Patents.
US3785765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary tobacco dryer
Assignee: Imperial Tobacco Canada Ltd
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Filing: 1972-02-17
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Granted: 1974-01-15
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Expires: 1992-02-17
Abstract
Abstract A tobacco dryer is disclosed which comprises a rotating substantially cylindrical drum in which the tobacco is dried. The drum has a first end and a second end and the tobacco which is to be dried enters the first end of the drum and leaves at the second end of the drum. Process air which has a low absolute humidity is introduced into the drum at the second end and flows through the drum in the opposite direction to the flow of tobacco, so as to pick up and remove from the drum, moisture released from the tobacco. A gas fired burner located within the dryer housing produces heating air. This heating air is forced over the exterior surfaces of the rotating drum at a velocity between 500 feet per minute and 3,500 feet per minute so as to increase the heat conductance through the rotating drum. In addition, the dryer is also provided with a controlled water spray which is introduced into the second end of the rotating drum and thereby controls the moisture content of the tobacco leaving the dryer.
Inventors
- 👤 L Rowell
- 👤 J Cartmell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:35
CPC Classifications
A; A24; A24B; A24B3/00; A24B3/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
166 words
A tobacco dryer comprising a rotating substantially cylindrical drum in which the tobacco is dried; said drum having a first end and a second end; means for introducing tobacco at said first end and means for removing tobacco at said second end; means for introducing process air into said drum at said second end and extracting said process air from said drum at said first end so that said process air travels in a direction within said drum opposite to that of said tobacco to pick up and remove from the drum, moisture released from the tobacco; heating means for maintaining the temperature of heating air; and means for circulating said heating air at a velocity between 500 fpm and 3,500 fpm over the outer surface of said drum to thereby achieve high heat conductance through said drum, wherein said circulating means includes a fan which forces said heating air into a pressurized plenum which encircles the exterior surface of said drum around its longitudinal centre.
Claim 2
Dependent Claim
166 words
A tobacco dryer comprising a rotating substantially cylindrical drum in which the tobacco is dried; said drum having a first end and a second end; means for introducing tobacco at said first end and means for removing tobacco at said second end; means for introducing process air into said drum at said second end and extracting said process air from said drum at said first end so that said process air travels in a direction within said drum opposite to that of said tobacco to pick up and remove from the drum, moisture released from the tobacco; heating means for maintaining the temperature of heating air; and means for circulating said heating air at a velocity between 500 fpm and 3,500 fpm over the outer surface of said drum to thereby achieve high heat conductance through said drum, wherein said circulating means includes a fan which forces said heating air into a pressurized plenum which encircles the exterior surface of said drum around its longitudinal centre.
Claim 3
Dependent Claim
87 words
A tobacco dryer according to claim 1, further comprising a stationary cylindrical shell surrounding said drum; said shell having its central portion interrupted by and in communication with said pressurized plenum and having its end portions in communication with the suction side of said fan and also in communication with the atmosphere, said stationary shell defining with said drum a narrow annular passage over a substantial portion of said drum for guiding part of the heating air from said plenum over the exterior surface of said drum.
Claim 4
Dependent Claim
92 words
A tobacco dryer according to claim 2 wherein a plurality of hollow paddles are arranged longitudinally on the interior surface of the drum, each of said paddles having a port through said drum in communication with said pressurized plenum; and a port being provided in said drum at each end of each each of said paddles for communicating the interior of said hollow paddles with the suction side of said fan and with the atmosphere, whereby part of said heating air in said plenum is circulated by said fan through said paddles.
Claim 5
Dependent Claim
31 words
A tobacco dryer according to claim 3, wherein said drum is tilted upwardly at said first end to allow said tobacco to pass through said drum under the influence of gravity.
Claim 6
Dependent Claim
16 words
A tobacco dryer according to claim 2, wherein said heating means is a gas fired burner.
Claim 7
Dependent Claim
25 words
A tobacco dryer according to claim 3, wherein said process air is slightly heated so as to reduce condensation on metal parts of said dryer.
Claim 8
Dependent Claim
44 words
A tobacco dryer according to claim 6, wherein a heat exchanger is disposed within an insulated housing which contains said drum, said heating means and said circulating means, said heat exchanger being operatively associated with said process air to slightly heat said process air.
Claim 9
Dependent Claim
17 words
A tobacco dryer according to claim 2, wherein said means for circulating is an electrically driven fan.
Claim 10
Dependent Claim
23 words
A dryer according to claim 2, wherein the velocity of said heating air over the outer surface of said drum is 2,000 fpm.
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |