US2937069A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating filters
Assignee: International Minerals and Chemical Corp
•
Filing: 1955-09-29
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Granted: 1960-05-17
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Expires: 1975-09-29
Abstract
No abstract record available.
Inventors
- 👤 James H Zoellner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:42
CPC Classifications
B; B01; B01D; B01D41/00; B01D41/04; C; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/22
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
183 words
A METHOD OF RESTORING THE PERMEABILITY OF BLINDED POLYETHYLENE FIBER FILTER CLOTH USED FOR SEPARATING INSOLUBLES FROM WET PROCESS PHOSPHORIC ACID PRODUCED BY ACIDULATING AND DIGESTING PHOSPHATE ROCK WITH A MINERAL ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID AND PHOSPHORIC ACID, AND FILTERING THE DIGESTED REACTION MIXTURE, IN WHICH THE FILTER CLOTH IS BLINDED WITH INSOLUBLE CALCIUM SULFATE DIHYDRATE, CALCIUM SULFATE ANHYDRITE, AND SILICA, WHICH COMPRISES IMMERSING SAID BLINDED CLOTH IN AN AQUEOUS ACIDIC SOLUTION CONTAINING HYDROFLUORIC ACID, SAID SOLUTION BEING SELECTED FROM THE GROUP CONSISTING OF (1) AN AQUEOUS SOLUTION CONTAINING HYDROFLUORIC ACID FORMED BY ABSORPING IN WATER DEN GASES PRODUCED BY ACIDULATION OF PHOSPHATE ROCK WITH AN ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID AND PHOSPHORIC ACID, AND (2) AN AQUEOUS SOLUTION CONTAINING HYDROFLUORIC ACID FORMED BY ABSORBING IN WATER VAPORS EVOLVED DURING THE CONCENTRATION OF WET PROCESS PHOSPHORIC ACID BY EVAPORATION OF WATER THEREFROM, SAIID IMMERSION BEING CONTINUED FOR A PERIOD OF BETWEEN ABOUT 30 MINUTES AND ABOUT 4 HOURS, UNTIL THE INSOLUBLE MATERIALS ARE DISSOLVED AND THE FILTER ACTION OF THE FILTER CLOTH IS RESTORED.
Claim 2
Independent Claim
183 words
A METHOD OF RESTORING THE PERMEABILITY OF BLINDED POLYETHYLENE FIBER FILTER CLOTH USED FOR SEPARATING INSOLUBLES FROM WET PROCESS PHOSPHORIC ACID PRODUCED BY ACIDULATING AND DIGESTING PHOSPHATE ROCK WITH A MINERAL ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID AND PHOSPHORIC ACID, AND FILTERING THE DIGESTED REACTION MIXTURE, IN WHICH THE FILTER CLOTH IS BLINDED WITH INSOLUBLE CALCIUM SULFATE DIHYDRATE, CALCIUM SULFATE ANHYDRITE, AND SILICA, WHICH COMPRISES IMMERSING SAID BLINDED CLOTH IN AN AQUEOUS ACIDIC SOLUTION CONTAINING HYDROFLUORIC ACID, SAID SOLUTION BEING SELECTED FROM THE GROUP CONSISTING OF (1) AN AQUEOUS SOLUTION CONTAINING HYDROFLUORIC ACID FORMED BY ABSORPING IN WATER DEN GASES PRODUCED BY ACIDULATION OF PHOSPHATE ROCK WITH AN ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID AND PHOSPHORIC ACID, AND (2) AN AQUEOUS SOLUTION CONTAINING HYDROFLUORIC ACID FORMED BY ABSORBING IN WATER VAPORS EVOLVED DURING THE CONCENTRATION OF WET PROCESS PHOSPHORIC ACID BY EVAPORATION OF WATER THEREFROM, SAIID IMMERSION BEING CONTINUED FOR A PERIOD OF BETWEEN ABOUT 30 MINUTES AND ABOUT 4 HOURS, UNTIL THE INSOLUBLE MATERIALS ARE DISSOLVED AND THE FILTER ACTION OF THE FILTER CLOTH IS RESTORED.
References Cited (Backward Citations)
US2198847A
Cited
US2666001A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-05-17 | 1963-11-16 | 1964-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-05-17 | 1967-11-16 | 1968-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-05-17 | 1971-11-16 | 1972-05-17 | $7700.00 | Window Closed / Lapsed |