Patent US3707775A successfully refreshed from Google Patents.
US3707775A
Expired / Lapsed
US
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Method of drying goods suspended in a gas stream
Assignee: Svenska Flaktfabriken AB
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Filing: 1970-09-24
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Granted: 1973-01-02
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Expires: 1990-09-24
Abstract
Abstract A method of drying material in which the drying material is suspended in a stream of gaseous drying medium in successive drying stages, the drying medium used being common to all of the stages and being circulated from the final stage into the preceding stage, and from the preceding stage into the initial stage and being heated between stages to an extent to elevate the temperature of the drying medium above its previous temperature whereby the drying medium in the first stage is at the highest temperature and highest moisture content and the temperature and moisture content decreases successively toward the final drying stage.
Inventors
- 👤 B Kaltin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:07
CPC Classifications
F; F26; F26B; F26B17/00; F26B17/10; F26B17/101
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
174 words
A method of drying finely distributed material sensitive to high temperatures in at least two drying stages comprising the steps of causing a predetermined flow of drying medium to flow through the drying stages, suspending the drying material into the drying medium in advance of each stage and separating the drying material from the drying medium subsequent to each stage, causing the same drying medium to flow generally countercurrent to the drying material by exhausting the drying medium separated from the drying material subsequent to the first stage, and directing all of the predetermined flow of drying medium separated from the material subsequent to the second stage into the inlet of the first stage, and heating said predetermined flow of drying medium intermediate said second stage and said first stage to a temperature above the temperature at which the drying medium enters the second stage so that the drying medium when it enters the first stage is at a higher temperature and has a higher moisture content than when it enters the second stage.
Claim 2
Independent Claim
174 words
A method of drying finely distributed material sensitive to high temperatures in at least two drying stages comprising the steps of causing a predetermined flow of drying medium to flow through the drying stages, suspending the drying material into the drying medium in advance of each stage and separating the drying material from the drying medium subsequent to each stage, causing the same drying medium to flow generally countercurrent to the drying material by exhausting the drying medium separated from the drying material subsequent to the first stage, and directing all of the predetermined flow of drying medium separated from the material subsequent to the second stage into the inlet of the first stage, and heating said predetermined flow of drying medium intermediate said second stage and said first stage to a temperature above the temperature at which the drying medium enters the second stage so that the drying medium when it enters the first stage is at a higher temperature and has a higher moisture content than when it enters the second stage.
Claim 3
Dependent Claim
92 words
A method according to claim 1 wherein the drying is effected in at least three stages including the step of passing all of the predetermined flow of drying medium separated from the drying material after the third stage into the inlet of the second stage and separately heating said predetermined flow of drying medium separated from the third stage so that its temperature is elevated above the temperature at which it entered the third stage whereby the temperature and heat content of the drying medium successively decrease throughout the entire three stages.
Claim 4
Dependent Claim
58 words
A method according to claim 1 including the step of filtering the predetermined flow of drying medium when it is drawn off from every drying stage, except from the first stage in the transport direction of the drying material, and substantially separated from the drying material before it is reheated and fed to the next foregoing drying step.
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) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |