US4926765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Furnace blower with external gas recycling for the reduction of NOx
Assignee: Individual
•
Filing: 1989-04-04
•
Granted: 1990-05-22
•
Expires: 2009-04-04
Abstract
Abstract A furnace system is provided with exhaust gas recirculation via a recirculation tube having an inlet mounted downstream of the furnace firing area and an inlet disposed in juxtaposition to the blower fan wheel of the furnace blower. The recirculated gases can enter the tube from either the stack or the firebox. The inlet penetrates the air intake plenum either axially thereof or at an angle thereto through a sidewall. The furnace includes both an air intake throttle and an air intake butterfly control valve. An exhaust gas recirculation control valve can be linked to the air intake control butterfly valve for their operation in concert. The air intake throttle is either a rigid baffle or a pivotable flap.
Inventors
- 👤 Walter Dreizler
- 👤 Ulrich Dreizler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:46
CPC Classifications
F; F23; F23C; F23C9/00; F23C2202/00; F23C2202/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
180 words
In a furnace construction comprising a furnace blower provided with a motor, blower wheel, ventilation housing, portend and a flame tube which is adapted for modulating burner operation with a combined fuel and air control, an air intake chamber attached at a front end of an air intake opening of the ventilation housing, a servomotor-activated air intake control butterfly valve disposed inside the air intake opening of said air intake chamber, a manually adjustable air throttling disk downstream of said air intake opening of the ventilation housing adapted to reduce NO x by external recycling of exhaust gas through a pipe means characterized in that an exhaust gas recirculation tube is guided through an external wall of air intake chamber and terminates in close proximity to the blower wheel, means to support a flange relative to the exhaust gas recirculation tube for adjustment of an air throttling disk which is movable by means of a threaded spindle, the entrance of exhaust gas recirculation tube being positioned downstream of air throttling disk directly in the low pressure area of blower wheel.
Claim 2
Dependent Claim
180 words
In a furnace construction comprising a furnace blower provided with a motor, blower wheel, ventilation housing, portend and a flame tube which is adapted for modulating burner operation with a combined fuel and air control, an air intake chamber attached at a front end of an air intake opening of the ventilation housing, a servomotor-activated air intake control butterfly valve disposed inside the air intake opening of said air intake chamber, a manually adjustable air throttling disk downstream of said air intake opening of the ventilation housing adapted to reduce NO x by external recycling of exhaust gas through a pipe means characterized in that an exhaust gas recirculation tube is guided through an external wall of air intake chamber and terminates in close proximity to the blower wheel, means to support a flange relative to the exhaust gas recirculation tube for adjustment of an air throttling disk which is movable by means of a threaded spindle, the entrance of exhaust gas recirculation tube being positioned downstream of air throttling disk directly in the low pressure area of blower wheel.
Claim 3
Dependent Claim
79 words
In a furnace construction as claimed in claim 1, further characterized in that the exhaust gas recirculation tube is provided with an exhaust control butterfly valve upstream of the air intake chamber, said exhaust gas control butterfly valve being actuated through composite linkage by the servomotor-activated air intake control butterfly valve and further that, upstream of said air intake control butterfly valve, a manually operated exhaust gas control butterfly valve is disposed in said exhaust gas recirculation tube 32b.
Claim 4
Dependent Claim
32 words
In a furnace construction as claimed in claim 1, further characterized in that exhaust gas recirculation tube is adapted to enter a boiler area of the furnace through a water-circulating jacket thereof.
Claim 5
Dependent Claim
31 words
In a furnace construction as claimed in claim 1, further characterized in that a rigid throttling disk is disposed in the air intake chamber upstream of said exhaust gas recirculation tube.
References Cited (Backward Citations)
US2224544A
Cited
US1634533A
Cited
US1691541A
Cited
US1609150A
Cited
US1702936A
Cited
US1831529A
Cited
US2813578A
Cited
US2918117A
Cited
US3260227A
Cited
US3367570A
Cited
US3460519A
Cited
US3741166A
Cited
US3868211A
Cited
DE2603988A1
Cited
US4312320A
Cited
US4728282A
Cited
US4725223A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-21 | 1993-11-20 | 1994-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-21 | 1997-11-20 | 1998-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-21 | 2001-11-20 | 2002-05-22 | $7700.00 | Window Closed / Lapsed |