US3670478A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-cleaning air filter
Assignee: Individual
•
Filing: 1970-06-24
•
Granted: 1972-06-20
•
Expires: 1990-06-24
Abstract
Abstract An air duct section with a cylindrical drum of washable filter material therein cradled on rollers and rotatable by a drive motor, but normally at rest. Upper and lower seal brushes are mounted to the duct and engage the drum, and water spray nozzles are provided inside and outside the drum, with timer controls on the motor and supply to the spray nozzles for rotating and spraying the drum at selected intervals, to wash accumulated deposits from the filter to a drain.
Inventors
- 👤 Clarke T Welsh
- 👤 Billy M Brumett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:27
CPC Classifications
F; F24; F24F; F24F13/00; F24F13/28; B; B01; B01D; B01D46/00; B01D46/24; B01D46/26
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
186 words
Air-filtering apparatus in combination with a return air duct of an air-conditioning system for cooling, said return air duct having inlet and outlet ends, a normally stationary cylindrically shaped filter transversely mounted in and substantially filling said duct for rotation about its axis whereby air flow between said inlet and outlet ends passes through the circumferential extent of said filter, means for restricting air flow past the periphery of said filter, means for washing said filter, means for rotating said filter, and means for activating simultaneously and periodically said washing and rotating means for a limited period of time whereby said filter is rotated only during washing and is otherwise stationary, said restricting means including a flexible sealing device extending inwardly from a wall of and being secured to said return air duct and having rubbing engagement with a periphery of said filter adjacent to said wall whereby particles collected by said filter may be dislodged during the aforesaid washing, said filter including a cylindrically shaped filter medium pervious to the flow of air whereby air flowing through said duct will pass diametrically through said filter.
Claim 2
Dependent Claim
186 words
Air-filtering apparatus in combination with a return air duct of an air-conditioning system for cooling, said return air duct having inlet and outlet ends, a normally stationary cylindrically shaped filter transversely mounted in and substantially filling said duct for rotation about its axis whereby air flow between said inlet and outlet ends passes through the circumferential extent of said filter, means for restricting air flow past the periphery of said filter, means for washing said filter, means for rotating said filter, and means for activating simultaneously and periodically said washing and rotating means for a limited period of time whereby said filter is rotated only during washing and is otherwise stationary, said restricting means including a flexible sealing device extending inwardly from a wall of and being secured to said return air duct and having rubbing engagement with a periphery of said filter adjacent to said wall whereby particles collected by said filter may be dislodged during the aforesaid washing, said filter including a cylindrically shaped filter medium pervious to the flow of air whereby air flowing through said duct will pass diametrically through said filter.
Claim 3
Dependent Claim
43 words
The apparatus of claim 1 in which said cylindrically shaped filter medium is of sheet-like material formed with portions extending radially of said cylindrical filter thereby providing additional surface area for filtering as compared with a smooth cylindrical shape for said sheet-like material.
Claim 4
Dependent Claim
33 words
The apparatus of claim 2 in which said radial portions of said filter medium are corrugations composed of ridges and furrows which are elongated and parallel to the axis of said cylindrical filter.
Claim 5
Dependent Claim
22 words
The apparatus of claim 3 in which said filter medium includes a plastic foam material sandwiched between two coaxial perforate metallic sheets.
Claim 6
Dependent Claim
55 words
The apparatus of claim 2 in which said restricting means includes two elongated brush devices extending in a direction from one end of said filter to the other, said brushes being mounted on said duct on diametrically opposite sides, respectively, of said filter and having rubbing engagement with said filter when the latter is rotated.
Claim 7
Dependent Claim
67 words
The apparatus of claim 5 in which said washing means includes water spray devices disposed internally and externally of said filter and a solenoid operated valve for controlling water flow thereto, said rotating means includes an electric motor, and said activating means includes a timing mechanism electrically connected to said motor and said solenoid and including means for activating and deactivating periodically said electric motor and solenoid.
Claim 8
Dependent Claim
77 words
The apparatus of claim 6 wherein said filter is rotatably supported in said duct by means of a series of spaced rollers journalled for rotation about axes parallel to said filter axis, said filter being supported on and between said rollers, one end of said filter being open, a stationary pipe disposed internally of said filter and extending outwardly of said open end for connection to said solenoid operated valve, said pipe carrying said internal spray devices.
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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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |