Patent US3894834A successfully refreshed from Google Patents.
US3894834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ignition and flame stabilization system for coal-air furnace
Assignee: Airco Inc
•
Filing: 1973-10-17
•
Granted: 1975-07-15
•
Expires: 1993-10-17
Abstract
Abstract A steam generating furnace with multiple coal-air burners has a corresponding number of supplemental oxygen-fuel burners, each mounted centrally of a coal-air burner respectively, for directing an oxy-fuel flame into a combustible mixture of powdered coal and air; the oxy-fuel burners are controlled to operate at a standby low-head setting during normal coal-air combustion, and are automatically controlled by flame sensing means during transitory coal-air flame deficiency and instability to operate at maximum heat for maintaining continuous furnace combustion. A manual over-ride switch operates the oxy-fuel burners at maximum heat such as for furnace starting, etc.
Inventors
- 👤 James W Estes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:27
CPC Classifications
F; F23; F23N; F23N1/00; F23N1/02; F23C; F23C1/00; F23C1/12; F23N2227/00; F23N2227/36; F23N2229/00; F23N2237/00; F23N2237/02; F23N2237/08; F23N2239/00; F23N2239/02; F23N2241/00; F23N2241/10; F23N5/00; F23N5/20; Y; Y02; Y02E; Y02E20/00; Y02E20/34
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
210 words
Apparatus for maintaining flames in excess of a predetermined length in a furnace comprising, fuel-air burner means for projecting a fuel-air flame in an annular converging pattern from a furnace wall; oxy-fuel burner means disposed substantially centrally within said fuel-air burner means for projecting oxyfuel flames into said converging fuel-air flames thereby augmenting the length and stability of said fuel-air flames; radiation responsive detection means, disposed along a side wall of said furnace adjacent to said wall from which said fuel-air and oxy-fuel flames are projected, for producing first and second signals upon said fuel-air flame failing to exceed and exceeding a predetermined length; main O2 and fuel valve means; auxiliary O2 and fuel valve means; means responsive to said first signal for closing said auxiliary O2 and fuel valve means and for opening said main O2 and fuel valve means to project a hot, intense oxy-fuel flame into said fuel-air flame thereby increasing the length of said fuel-air flame to at least said predetermined length; and means responsive to said second signal for closing said main O2 and fuel valve means and opening said auxiliary O2 and fuel valve means to maintain a low intensity, standby oxy-fuel flame as long as said fuel-air flame length exceeds said predetermined length.
Claim 2
Dependent Claim
210 words
Apparatus for maintaining flames in excess of a predetermined length in a furnace comprising, fuel-air burner means for projecting a fuel-air flame in an annular converging pattern from a furnace wall; oxy-fuel burner means disposed substantially centrally within said fuel-air burner means for projecting oxyfuel flames into said converging fuel-air flames thereby augmenting the length and stability of said fuel-air flames; radiation responsive detection means, disposed along a side wall of said furnace adjacent to said wall from which said fuel-air and oxy-fuel flames are projected, for producing first and second signals upon said fuel-air flame failing to exceed and exceeding a predetermined length; main O2 and fuel valve means; auxiliary O2 and fuel valve means; means responsive to said first signal for closing said auxiliary O2 and fuel valve means and for opening said main O2 and fuel valve means to project a hot, intense oxy-fuel flame into said fuel-air flame thereby increasing the length of said fuel-air flame to at least said predetermined length; and means responsive to said second signal for closing said main O2 and fuel valve means and opening said auxiliary O2 and fuel valve means to maintain a low intensity, standby oxy-fuel flame as long as said fuel-air flame length exceeds said predetermined length.
Claim 3
Dependent Claim
69 words
Apparatus as defined in claim 1 further comprising manually operable switch means connected to said means responsive to said second signal such that upon operation of said switch means, said second signal is overridden thereby supplying fuel and oxygen to said oxy-fuel burner to enable projection of said hot, intense oxy-fuel flame notwithstanding an indication by said radiation responsive detection means that said fuel-air flame exceeds said predetermined length.
Claim 4
Dependent Claim
33 words
A furnace combustion system as specified in claim 1 wherein the oxygen-fuel burner means is of the rocket type for projecting oxygen-fuel flames into the fuel-air mixture at different rates of heat output.
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) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |