Patent US3134735A successfully refreshed from Google Patents.
US3134735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Open gravity filters
Assignee: Greenleaf Enterprises Inc
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Filing: 1961-11-28
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Granted: 1964-05-26
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Expires: 1981-11-28
Abstract
No abstract record available.
Inventors
- 👤 Jr John W Greenleaf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:06
CPC Classifications
B; B01; B01D; B01D35/00; B01D35/16; B01D24/00; B01D24/02; B01D24/20; B01D24/24; B01D24/46; B01D24/4631; B01D35/12; B01D2201/00; B01D2201/20; B01D2201/204; B01D2201/206
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
155 words
A GRAVITY FLOW BACKWASH FILTER COMPRISING A PLURALITY OF RELATIVELY ADJOINING FILTER UNITS, EACH SAID FILTER UNIT COMPRISING A HORIZONTAL FILTER BED SPACED ABOVE THE BOTTOM OF THE UNIT TO LEAVE A DRAIN SPACE BENEATH SAID BED, EACH SAID UNIT OPENING UPWARDLY IMMEDIATELY ABOVE ITS SAID FILTER BED INTO DIRECT COMMUNICATION WITH THE ATMOSPHERE, INFLUENT SUPPLY MEANS FOR SAID FILTER COMMON TO ALL SAID UNITS, MEANS FOR SELECTIVELY DISCONTINUING THE SUPPLY OF INFLUENT TO ANY GIVEN UNIT, A FILTRATE CONDUIT COMMON TO ALL OF SAID UNITS, OVERFLOW MEANS FOR MAINTAINING FILTRATE THEREIN AT A SUBSTANTIALLY CONSTANT LEVEL ABOVE THE FILTER BEDS, SAID INFLUENT SUPPLY MEANS BEING DISPOSED ABOVE THE LEVEL OF SAID FILTRATE CONDUIT, MEANS DEFINING UNRESTRICTED LIQUID PASSAGES PERMITTING BI-DIRECTIONAL FLOW TO FILTRATE BETWEEN SAID FILTRATE CONDUIT AND SAID RESPECTIVE DRAIN SPACES IN DIRECTIONS RESPONSIVE SOLELY TO DIFFERENCES IN LIQUID LEVEL ABOVE SAID FILTER BEDS AND IN SAID FILTRATE CONDUIT, IN COMBINATION WITH BACKWASH
Claim 2
Dependent Claim
155 words
A GRAVITY FLOW BACKWASH FILTER COMPRISING A PLURALITY OF RELATIVELY ADJOINING FILTER UNITS, EACH SAID FILTER UNIT COMPRISING A HORIZONTAL FILTER BED SPACED ABOVE THE BOTTOM OF THE UNIT TO LEAVE A DRAIN SPACE BENEATH SAID BED, EACH SAID UNIT OPENING UPWARDLY IMMEDIATELY ABOVE ITS SAID FILTER BED INTO DIRECT COMMUNICATION WITH THE ATMOSPHERE, INFLUENT SUPPLY MEANS FOR SAID FILTER COMMON TO ALL SAID UNITS, MEANS FOR SELECTIVELY DISCONTINUING THE SUPPLY OF INFLUENT TO ANY GIVEN UNIT, A FILTRATE CONDUIT COMMON TO ALL OF SAID UNITS, OVERFLOW MEANS FOR MAINTAINING FILTRATE THEREIN AT A SUBSTANTIALLY CONSTANT LEVEL ABOVE THE FILTER BEDS, SAID INFLUENT SUPPLY MEANS BEING DISPOSED ABOVE THE LEVEL OF SAID FILTRATE CONDUIT, MEANS DEFINING UNRESTRICTED LIQUID PASSAGES PERMITTING BI-DIRECTIONAL FLOW TO FILTRATE BETWEEN SAID FILTRATE CONDUIT AND SAID RESPECTIVE DRAIN SPACES IN DIRECTIONS RESPONSIVE SOLELY TO DIFFERENCES IN LIQUID LEVEL ABOVE SAID FILTER BEDS AND IN SAID FILTRATE CONDUIT, IN COMBINATION WITH BACKWASH
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) | 1967-05-26 | 1967-11-25 | 1968-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-05-26 | 1971-11-25 | 1972-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-05-26 | 1975-11-25 | 1976-05-26 | $7700.00 | Window Closed / Lapsed |