US3744543A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for steam drying filter cake
Assignee: Envirotech Corp
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Filing: 1970-11-02
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Granted: 1973-07-10
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Expires: 1990-11-02
Abstract
Abstract A method is disclosed for steam drying filter cake on a drum or disc type vacuum filter having a steam drying cycle wherein optimum cake thickness and moisture content is obtained at optimum thermal efficiency by controlling the vacuum during cake formation and controlling the filtration rate by control of the speed of rotation of the filter element.
Inventors
- 👤 R Emmett
- 👤 D Dahlstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:51
CPC Classifications
B; B01; B01D; B01D37/00; B01D37/04; B01D33/00; B01D33/15; B01D33/21; B01D33/58; B01D33/62; B01D33/64; F; F26; F26B; F26B3/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
149 words
A method for drying a filter cake formed by continuous filtration of a feed slurry in a closed hood type rotary vacuum filter comprising: a. continuously monitoring and controlling a vacuum applied to that portion of the interior of the filter element positioned below the surface of the feed slurry to deposit and maintain an optimized cake thickness in a zone above the level of the feed slurry; b. controlling the filtration rate by additionally and continuously monitoring and controlling the speed of rotation of the filter element; c. directing steam into the zone above the feed slurry at a rate such that substantially all of the steam is condensed in passing through the filter cake so as to maintain the condensation front at the filter cake-filter interface. and d. applying a vacuum to the interior of the filter element to draw the steam toward the filter cake interface.
Claim 2
Independent Claim
149 words
A method for drying a filter cake formed by continuous filtration of a feed slurry in a closed hood type rotary vacuum filter comprising: a. continuously monitoring and controlling a vacuum applied to that portion of the interior of the filter element positioned below the surface of the feed slurry to deposit and maintain an optimized cake thickness in a zone above the level of the feed slurry; b. controlling the filtration rate by additionally and continuously monitoring and controlling the speed of rotation of the filter element; c. directing steam into the zone above the feed slurry at a rate such that substantially all of the steam is condensed in passing through the filter cake so as to maintain the condensation front at the filter cake-filter interface. and d. applying a vacuum to the interior of the filter element to draw the steam toward the filter cake interface.
Claim 3
Independent Claim
181 words
A method for drying a filter cake formed by continuous filtration of a feed slurry on a closed hood type rotary vacuum filter comprising: a. continuously monitoring and controlling a vacuum applied to the filter element in a zone below the surface of the feed slurry to maintain an optimized cake thickness in a zone above the level of the feed slurry; b. controlling the filtration rate by continuously monitoring and controlling the speed of rotation of the filter element; c. directing steam into the zone above the feed slurry at a rate such that substantially all of the steam is condensed in passing through the filter cake so as to maintain the condensation front at the filter cake-filter interface; and d. applying a vacuum to the filter element to draw the steam toward the filter cake interface; e. said directed steam passed to the filter cake in said zone being at a temperature from about 250* to about 300 * F. and the steam is passed at the amount of 50 to 100 Kg. per metric ton of filter cake.
Claim 4
Independent Claim
181 words
A method for drying a filter cake formed by continuous filtration of a feed slurry on a closed hood type rotary vacuum filter comprising: a. continuously monitoring and controlling a vacuum applied to the filter element in a zone below the surface of the feed slurry to maintain an optimized cake thickness in a zone above the level of the feed slurry; b. controlling the filtration rate by continuously monitoring and controlling the speed of rotation of the filter element; c. directing steam into the zone above the feed slurry at a rate such that substantially all of the steam is condensed in passing through the filter cake so as to maintain the condensation front at the filter cake-filter interface; and d. applying a vacuum to the filter element to draw the steam toward the filter cake interface; e. said directed steam passed to the filter cake in said zone being at a temperature from about 250* to about 300 * F. and the steam is passed at the amount of 50 to 100 Kg. per metric ton of filter cake.
Claim 5
Dependent Claim
21 words
The invention defined in claim 2 wherein the dry filter cake is from about 1/4 inch to 2 inches in thickness.
Claim 6
Dependent Claim
44 words
The invention defined in claim 3 wherein the formed cake is about 1/4 inch to about 1/2 inch in thickness when the particles in the slurry to be filtered are in the range of 30 to 40 percent or more at - 200 mesh.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |