US3928006A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for signalling dirty filters
Assignee: Individual
•
Filing: 1974-08-29
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Granted: 1975-12-23
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Expires: 1994-08-29
Abstract
Abstract As a filter becomes dirty in a circulating air system such as found in furnaces and air conditioners, its pores become clogged providing a higher resistance to air flow therethrough and tends to bulge when the blower is operative. A position sensitive electrical switch is positioned to detect a predetermined extent of filter bulge thereby to operate an end-of-filter-life signal.
Inventors
- 👤 Richard P Martineau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:32
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/0084; B01D46/0086; B01D46/10; Y; Y10; Y10S; Y10S55/00; Y10S55/34
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
169 words
A SIGNALLING DEVICE FOR AUTOMATICALLY DESIGNATING THE END OF USEFUL FILTER LIFE IN A CIRCULATING AIR SYSTEM SUCH AS A FURNACE, COMPRISING IN COMBINATION, A CIRCULATING AIR PASSAWAY, A BLOWER FORCING A FLOW OF AIR THROUGH SAID PASSAWAY, A SUBSTANTIALLY PLANAR FILTER ARRANGED IN SAID PASSAGEWAY TO INTERCEPT THE FLOW OF SAID AIR, RIGID PERPIHERAL MOUNTING STRUCTURE FOR SAID FILTER CONFINING IT IN PLACE AT THE EDGES AND PERMITTING THE UNSUPPORTED CENTRAL PORTION OF SAID FILTER TO FLEX IN THE DIRECTION OF AIR FLOW THERETHROUGH, AND MEANS INCLUDING A SWITCH FOR SIGNALLING END OF LIFE POSITIONED FOR ACTUATION BY THE CROWN OF THE BOWING MOVEMENT OF SAID CENTRAL PORTION AFTER IT IS FLEXED A PREDETERMINED DISTANCE AS A RESULT OF INCREASED RESISTANCE TO AIR FLOW WHEN IT HAS BECOME PARTIALLY CLOGGED BY RETENTION OF DUST AND THE LIKE. AND SWITCH HAVING A MOUNTING STRUCTURE SUPPORTING SAID SWITCH ADJACENT SAID FILTER MOUNTING STRUCTURE AND HAVING ADJUSTING MEANS THEREON FOR ESTABLISHING SAID PREDETERMINED DISTANCE FOR RELATIVELY POSITIONING SAID TWO MOUNTING STRUCTURES.
Claim 2
Dependent Claim
169 words
A SIGNALLING DEVICE FOR AUTOMATICALLY DESIGNATING THE END OF USEFUL FILTER LIFE IN A CIRCULATING AIR SYSTEM SUCH AS A FURNACE, COMPRISING IN COMBINATION, A CIRCULATING AIR PASSAWAY, A BLOWER FORCING A FLOW OF AIR THROUGH SAID PASSAWAY, A SUBSTANTIALLY PLANAR FILTER ARRANGED IN SAID PASSAGEWAY TO INTERCEPT THE FLOW OF SAID AIR, RIGID PERPIHERAL MOUNTING STRUCTURE FOR SAID FILTER CONFINING IT IN PLACE AT THE EDGES AND PERMITTING THE UNSUPPORTED CENTRAL PORTION OF SAID FILTER TO FLEX IN THE DIRECTION OF AIR FLOW THERETHROUGH, AND MEANS INCLUDING A SWITCH FOR SIGNALLING END OF LIFE POSITIONED FOR ACTUATION BY THE CROWN OF THE BOWING MOVEMENT OF SAID CENTRAL PORTION AFTER IT IS FLEXED A PREDETERMINED DISTANCE AS A RESULT OF INCREASED RESISTANCE TO AIR FLOW WHEN IT HAS BECOME PARTIALLY CLOGGED BY RETENTION OF DUST AND THE LIKE. AND SWITCH HAVING A MOUNTING STRUCTURE SUPPORTING SAID SWITCH ADJACENT SAID FILTER MOUNTING STRUCTURE AND HAVING ADJUSTING MEANS THEREON FOR ESTABLISHING SAID PREDETERMINED DISTANCE FOR RELATIVELY POSITIONING SAID TWO MOUNTING STRUCTURES.
References Cited (Backward Citations)
US2580642A
Cited
US2789175A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |