Patent US3899417A successfully refreshed from Google Patents.
US3899417A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In-line pressure sifter
Assignee: Fred D Pfening Co
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Filing: 1973-09-19
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Granted: 1975-08-12
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Expires: 1993-09-19
Abstract
Abstract A gyratory, industrial-type pressure sifter adapted to be connected in a conduit or conveyor pipe system and through which air-entrained, pulverulent solids are caused to flow under pressure, whereby to sift and separate oversize solids from the air-conveyed fines, the sifter being characterized by a novel arrangement of sieves and baffles which promote the efficient, substantially uninterrupted sifting of air-entrained fines during their flow through the associated conveyor conduit system, while ensuring the removal from the influent solids of any oversize particles or contaminants.
Inventors
- 👤 Gilbert C Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:18
CPC Classifications
B; B07; B07B; B07B1/00; B07B1/28; B07B1/38; B07B4/00; B07B4/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
152 words
IN A GYRATORY PRESSURE SIFTER WHICH INCLUDES A GENERALLY VERTICALLY ARRANGED HOUSING HAVING AN UPPER END CLOSURE PROVIDED WITH AN INLET FOR AIR-ENTRAINED SOLID PARTICLES TO BE SIFTED AND A LOWER END CLOSURE HAVING A PRIMARY OUTLET FOR THE DISCHRGE OF AIR-ENTRAINED, SIFTED FINES AND A SECONDARY OUTLET FOR THE GRAVITATIONAL DISCHARGE OF UNSIFTED, LARGER SIZE SOLID PARTICLES FROM SAID HOUSING, AND A PLURALITY OF GENERALLY HORIZONTALLY ARRANGED, VERTICALLY SPACED APART SIEVE ASSEMBLIES POSITIONED IN SAID HOUSING BETWEEN SAID UPPER AND LOWER END CLOSURES, THAT IMPROVEMENT WHICH COMPRISES: AN UPWARDLY TAPERING FRUSTO-CONICAL INLET CONDUIT HAVING A WIDER LOWER END CONNECTED WITH THE UPPER END CLOSURE OF SAID HOUSING AND DEFINING A DOWNWARDLY AND OUTWARDLY FLARING INLET PASSAGE INTO SAID HOUSING, AND A DOWNWARDLY TAPERING FUNNEL-SHAPED SEPARATOR RING POSITIONED INTERMEDIATE THE ENDS OF SAID INLET CONDUIT AND IN COAXIAL, INWARDLY SPACED RELATION THERETO, SAID SEPARATOR RING BEING SPACED DOWNWARDLY FROM THE UPPER END
Claim 2
Dependent Claim
152 words
IN A GYRATORY PRESSURE SIFTER WHICH INCLUDES A GENERALLY VERTICALLY ARRANGED HOUSING HAVING AN UPPER END CLOSURE PROVIDED WITH AN INLET FOR AIR-ENTRAINED SOLID PARTICLES TO BE SIFTED AND A LOWER END CLOSURE HAVING A PRIMARY OUTLET FOR THE DISCHRGE OF AIR-ENTRAINED, SIFTED FINES AND A SECONDARY OUTLET FOR THE GRAVITATIONAL DISCHARGE OF UNSIFTED, LARGER SIZE SOLID PARTICLES FROM SAID HOUSING, AND A PLURALITY OF GENERALLY HORIZONTALLY ARRANGED, VERTICALLY SPACED APART SIEVE ASSEMBLIES POSITIONED IN SAID HOUSING BETWEEN SAID UPPER AND LOWER END CLOSURES, THAT IMPROVEMENT WHICH COMPRISES: AN UPWARDLY TAPERING FRUSTO-CONICAL INLET CONDUIT HAVING A WIDER LOWER END CONNECTED WITH THE UPPER END CLOSURE OF SAID HOUSING AND DEFINING A DOWNWARDLY AND OUTWARDLY FLARING INLET PASSAGE INTO SAID HOUSING, AND A DOWNWARDLY TAPERING FUNNEL-SHAPED SEPARATOR RING POSITIONED INTERMEDIATE THE ENDS OF SAID INLET CONDUIT AND IN COAXIAL, INWARDLY SPACED RELATION THERETO, SAID SEPARATOR RING BEING SPACED DOWNWARDLY FROM THE UPPER END
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |