US3847092A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic bed level control for furnaces
Assignee: Combustion Engineering Inc
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Filing: 1973-12-10
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Granted: 1974-11-12
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Expires: 1993-12-10
Abstract
Abstract An automatic bed level control system is provided for furnaces which burn a material on a bed, such as chemical recovery furnaces and the like. Optical sensing means sense light emitted by the burning of the bed material and provide a signal which varies as a function of the intensity of the sensed light. The sensing means are structured and oriented to respond to light emanating only from a particular, vertically limited zone in the furnace, such that variations in the intensity of the sensed light are indicative of variations in bed level. The signal provided by the sensing means is then used to regulate some bed level controlling parameter, as for instance primary air flow.
Inventors
- 👤 L Gilbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:00
CPC Classifications
F; F23; F23N; F23N5/00; F23N5/02; F23N5/08; F23N5/082; F23G; F23G5/00; F23G5/50; F23G7/00; F23G7/04; F23K; F23K3/00; F23K3/22
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
87 words
In a furnace in which a material is burned on a bed, emitting light, and in which the level of said bed is a function of a control variable, means for controlling the level of said bed comprising: a. means for sensing said emitted light and providing a signal which varies as a function of the intensity of said sensed light and is indicative of the level of said bed; and b. means responsive to said signal for controlling said control variable to control said bed depth.
Claim 2
Dependent Claim
87 words
In a furnace in which a material is burned on a bed, emitting light, and in which the level of said bed is a function of a control variable, means for controlling the level of said bed comprising: a. means for sensing said emitted light and providing a signal which varies as a function of the intensity of said sensed light and is indicative of the level of said bed; and b. means responsive to said signal for controlling said control variable to control said bed depth.
Claim 3
Dependent Claim
42 words
The apparatus of claim 1 wherein said sensing means sense light only from a particular zone in said furnace such that the intensity of said sensed light is related to the level of the bed with respect to the point of measurement.
Claim 4
Dependent Claim
17 words
The apparatus of claim 2 wherein said particular zone is of limited vertical extent within said furnace.
Claim 5
Dependent Claim
37 words
The apparatus of claim 3 wherein primary air is supplied to said furnace for burning said material and comprises said control variable; and said signal responsive means include means for varying the flow of said primary air.
Claim 6
Dependent Claim
63 words
The apparatus of claim 4 wherein said primary air flow varying means include a damper and said signal responsive means further include an actuator operatively connected to said damper and responsive to said signal from said light sensor for varying the position of said damper in a direction to maintain said sensed light at a desired value commensurate with a desired bed level.
Claim 7
Dependent Claim
73 words
The apparatus of claim 5 wherein said primary air is supplied to said furnace through a plurality of air ducts communicating with said furnace, each duct providing air to a particular associated region of said furnace; each said duct includes a separate said damper therein; and a said sensing means is associated with each said air duct and associated damper to control air supply to the said particular associated region of said furnace.
Claim 8
Dependent Claim
35 words
The apparatus of claim 6 wherein each said air duct includes an air port at its downstream end and each said associated light sensing means views the interior of said furnace through said air port.
Claim 9
Dependent Claim
48 words
The apparatus of claim 7 wherein said furnace is a chemical recovery furnace; said material being burned includes a sodium compound and said light includes a wavelength characteristic of excited sodium atoms; and said sensing means is responsive only to said light wavelength characteristic of excited sodium atoms.
Claim 10
Dependent Claim
37 words
The apparatus of claim 2 wherein primary air is supplied to said furnace for burning said material and comprises said control variable; and said signal responsive means include means for varying the flow of said primary air.
Claim 11
Dependent Claim
48 words
The apparatus of claim 9 wherein said furnace is a chemical recovery furnace; said material being burned includes a sodium compound and said light includes a wavelength characteristic of excited sodium atoms; and said sensing means is responsive only to said light wavelength characteristic of excited sodium atoms.
Claim 12
Dependent Claim
93 words
In a furnace in which a material is burned on a bed, emitting light, and in which the level of said bed is a function of the flow of primary air supplied thereto, a method for controlling the level of said char bed comprising the steps of: a. sensing only said light emanating from a particular zone in said furnace to provide a control signal which varies as a function of the intensity of said sensed light; and b. varying the flow of said primary air as a function of said control signal.
Claim 13
Dependent Claim
93 words
In a furnace in which a material is burned on a bed, emitting light, and in which the level of said bed is a function of the flow of primary air supplied thereto, a method for controlling the level of said char bed comprising the steps of: a. sensing only said light emanating from a particular zone in said furnace to provide a control signal which varies as a function of the intensity of said sensed light; and b. varying the flow of said primary air as a function of said control signal.
Claim 14
Dependent Claim
32 words
The method of claim 11 wherEin said zone is of limited vertical extent such that the intensity of said sensed light varies as a function of the depth of said char bed.
Claim 15
Dependent Claim
19 words
The method of claim 10 wherein said air flow is varied inversely of the intensity of said sensed light.
Claim 16
Dependent Claim
65 words
The method of claim 12 wherein said material being burned includes a sodium compound and said light includes a wavelength characteristic of excited sodium atoms and wherein said step of sensing said light includes sensing only that light having a wavelength characteristic of excited sodium atoms, whereby said control signal is indicative only of the intensity of said light wavelength characteristic of excited sodium atoms.
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |