|Publication number||US3867092 A|
|Publication date||Feb 18, 1975|
|Filing date||Feb 27, 1974|
|Priority date||Feb 27, 1974|
|Also published as||CA1020077A, CA1020077A1, DE2503552A1|
|Publication number||US 3867092 A, US 3867092A, US-A-3867092, US3867092 A, US3867092A|
|Inventors||Sage Warnie L, Scott Edwin D|
|Original Assignee||Babcock & Wilcox Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (11), Classifications (15)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 1191 Sage et a1. Feb. 18, 1975 1 IGNITOR 3,650,476 3/1972 Rackley et a]. 239 431 3,747,860 7/1973 Habers 239/431  Inventors: Warnie L. Sage, Louisville; Edwin D. Scott, Alliance, both of Ohio  Assignee: The Babcock and Wilcox Company,
New York, NY.
22 Filed: Feb. 27, 1974 21 Appl. No: 446,187
 11.8. Cl 431/354, 239/431, 239/432, 239/434, 431/175  Int. Cl. A62c 31/00, F23d 11/00  Field of Search 239/426, 431, 432, 434; 431/167,175, 354
 References Cited UNITED STATES PATENTS 1,826,776 10/1931 Gunther ..239/434X Primary Examiner-Edward G. Favors Attorney, Agent, or Firm-Joseph M. Maguire; Robert J. Edwards  ABSTRACT A liquid fuel fired ignitor including an atomizing device comprising a tubular barrel and an inner tube projecting into the barrel and discharging into the annular passage formed therebetween and wherein liquid fuel is supplied to the barrel and. atomizing fluid is supplied to the tube, with the fuel being atomized by the fluid discharging from the tube and thereafter further atomized by a pair of spaced orifice plates disposed within the barrel downstream fuel flow-wise of the tube.
5 Claims, 4 Drawing Figures PATENTEB FEB I 81875 SHEET 2 OF 2 IGNITOR BACKGROUND OF THE INVENTION The present invention relates to liquid fuel type ignition systems and more particularly to a device for atomizing the fuel preparatory to firing from the ignitor.
It is common practice in the design of fuel burning equipment to provide ignitors for initiating combustion of the fuel discharged from main fuel burners. Generally, these ignitors are used only intermittently for short periods, i.e., during start up. and for stabilizing flame conditions during low load and upset conditions. However, on larger central station vapor generating units, a practice has developed whereby ignitors are used to the exclusion of the main fuel burners to introduce the relatively low fuel input required to heat the vapor generator under controlled temperature conditions up to the time when the electric generators are synchronized into the main system. This phase of the start up operation normally takes two to four hours.
Heretofore, liquid fuel type ignitors have resorted to mechanical atomization of the fuel, a method which, while adequate, has the disadvantage of giving rise to a highly visible stack plume, an ecologically unattractive condition particularly when present over a sustained period of time.
SUMMARY OF THE INVENTION The present invention uses a pressurized fluid to atomize the liquid fuel prior to its discharge from the ignitor.
Accordingly, there is provided an ignition system which includes an atomizing device comprising a tubu lar barrel, an inner tube coaxial with the barrel and projecting thereinto and cooperating therewith to form an annular passage therebetween. A pressurized liquid fuel is supplied to the annular passage and a pressurized atomizing fluid is supplied to the inner tube. The atomizing fluid is at a higher pressure than the liquid fuel and is discharged into the annular passage through a plurality of ports formed near the distal end of the inner tube and oriented in a direction normal to the barrel and tube axis. The fuel stream flowing through the passage is sheared by the high velocity atomizing fluid exiting from the ports. The fuel leaving the annular passage is further atomized through impingement and flow velocity increase as it serially passes through spaced first and second orifices disposed within the barrel downstream fuel flow-wise of the inner tube.
One embodiment of the invention comprises having the atomizing device as an integral part of the ignitor with the inlet end portion of the ignitor nozzle forming the atomizing device tubular barrel. An alternative embodiment includes having the atomizing device as a separate unit from the ignitor, in which instance, a single device may provide atomized fuel to a plurality of ignitors.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional side view of the main embodiment of the invention depicting the atomizing device as an integral part of the ignitor.
FIG. 2 is a side view of an alternate embodiment of the invention associated with a main fuel burner and depicting the atomizing device as a unit separate from the ignitor.
FIG. 3 is a schematic plan view of the alternate embodiment of FIG. 2 depicting three ignitors serviced by one atomizing device.
FIG. 4 is a sectional side view of the atomizing device as presented in the alternate embodiment ofFlG. 2 and associated with an ignitor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. I, there is shown the main embodiment ofthe invention comprising a liquid fuel fired ignitor 10 including a nozzle I2 threadably joined at one end to a body portion l4 and at the other end to a sprayer head 16. The body portion 14 contains a passage 18 having an inlet opening 211) to admit liquid fuel to the ignitor I0, and a threaded outlet opening 22, the latter engages a like threaded segment ofthe inlet portion 24 of the nozzle 12 to provide flow through communication between the passage 18 and the bore 26 of nozzle 12. A seal ring 28 is fitted around the inlet end 24 adjacent the leading edge of outlet opening 22 to prevent leakage of fuel between the nozzle 12 and the body portion 14.
In accordance with the main embodiment of the invention. the rear end face of the body portion 14 has an opening which admits an internally threaded tubular coupling 30, the latter being seal-welded to the body portion 14. An inner tube 32 projects from within the coupling 30 into the nozzle inlet end portion 24 which also forms the tubular barrel of the atomizing device 34. The tube 32 has an open inlet and a closed outlet end and discharges through a plurality of ports 36 into an annular passage 33 formed between the cylindrical walls of tubular barrel 24 and inner tube 32. The ports 36 are circumferentially spaced about the cylindrical wall near the outlet end of tube 32. The inlet end portion 38 of tube 32 is threaded for engagement with the coupling 30 in such manner as to permit linear shifting of the position of the ports 36 with respect to the inlet and outlet ends of barrel 24 within prescribed limits. A lock nut 40 fixedly secures the tube 32 to the coupling 30 to maintain the selected position of the ports 36 with respect to the nozzle 12. It will be appreciated that the allowable range for adjustment of port position is governed by the length of the threaded portion 38. The repositioning of the ports 36 is effected by uncoupling the nozzle 12 from the body portion 14. loosening the lock nut 40 and rotating the tube 32 within the coupling 30 to achieve the desired port location with respect to the nozzle 12. When the repositioning of ports 36 is complete, the lock nut 40 should be tightened before recoupling the nozzle 12 to the body portion 14.
The inlet end portion 24 forming the tubular barrel of atomizing device 34 includes a pair of spaced orifice plates 42 and 44 situated downstream fuel flow-wise and in spaced relation to the most forward position of the tube 32. Plate 42 is formed with a single orifice 46 extending through the center thereof while plate 44 has an imperforate center surrounded by a plurality of cir cularly spaced orifices 48. The outlet end of nozzle 12 is threaded to receive a like threaded portion of sprayer head I6. The leading end face of the sprayer head I6 is bevelled to form a frusto-conical section for accommodating a plurality of circularly spaced discharge openings 50 lying in a direction divergent from the central axis of the nozzle 12.
Referring to FIG. 2, there is shown an alternate embodiment of the invention in association with a pulverized fuel burner, and including an opening in the furnace wall 52 of a vapor generating unit defined by a frusto-conical burner port 54 having a throat section 56. The inner surface of the port 54 diverges toward the furnace side of the wall 52 and is cooled by fluid conducting tubes 58 which line the furnace wall 52. Spaced from the wall 52 is a burner windbox front or outer burner wall 60 which defines therebetween an air chamber or windbox 62 for receiving a regulated quantity of combustion air. Suitable dampers, not illustrated, may be provided to control the quantity of combustion air delivered to the windbox 62.
A pulverized fuel burner is partly shown at 64 and includes a cylindrical fuel nozzle 66 which extends through an opening in the outer burner wall 60 and across the windbox 62 to a point adjacent the throat 56. A distance piece 68 is slidably supported within the fuel nozzle by a suitable spider 70 and is equipped at its distal end with an impeller 72, the latter being normally positioned slightly beyond the discharge end of the fuel nozzle 66. The pulverized fuel is carried from the mill (not shown) in a stream of primary air and is injected into the burner port 54 by the fuel nozzle 66. Combustion air in the form of secondary air is supplied to the injected fuel through an air register assembly 74 which is disposed within the windbox 62 and adjacent the burner throat 56. As shown, theair register assembly 74 is circumferentially spaced about the discharge end of fuel nozzle 66, and includes front and rear end wall members 76 and 78 and an entrance cone 80 connected to the furnace wall 52 and converging toward the burner throat 56. Circumferentially spaced and connected between the end wall members 76 and 78 and about the periphery thereof are a plurality of air register doors 82 which are adapted to pivot between open and closed positions. With the air doors 82 in open position, the air register 74 is rendered in communication with the windbox 62. If desired, the air doors 82 may be suitably geared, linked or otherwise connected together so as to be responsive to an operating means (not shown) which may be either manually or automatically controlled. In addition to controlling the secondary air supply, the air register doors 82 are also arranged to impart a whirling or spinning movement to the air flowing through the register assembly 74.
An ignitor assembly is depicted at 83 and includes a support tube 86 which extends through an opening in the outer burner wall 60 in a direction preferably sloped toward the central axis of the burner port 54. The support tube 86 houses a pair of guide tubes 85 and 87 so as to separately accommodate an electrode 88 and a liquid fuel fired ignitor 10A. The electrode 88 is of a type which is well known in the art and comprises a high voltage lead 90 energized from a suitable high voltage source such as a transformer (not shown) and connected to one end of an electrode rod 92, the latter being positioned within the guide tube 85 by means of insulators (not shown). Attached to the interior ofguide tube 85 is a ground electrode rod 94 which extends parallel to the rod 92 and has formed on its end a right angle bend terminating adjacent the end of rod 94 to form an electric spark gap.
The liquid fuel ignitor 10A extends through the guide tube 87 and has its sprayer head 16A positioned adjacent the spark gap so that the ignitor fuel is readily lighted when the system is energized. The inlet end of the guide tube 87 is fitted with a yoke assembly 96 which serves as a coupling seat between the ignitor body portion 14A and liquid fuel connecting line 98. A leak-proof fit is achieved between the yoke 96 and the body portion 14A by introducing a gasket (not shown) between the mating surfaces and applying pressure with a locking device 99.
in accordance with an alternate embodiment of the invention, the atomizing device 34A is shown as a unit physically separate from the ignitor A and comprising a tubular barrel 24A discharging into theliquid fuel connecting line 98. A T-fitting is flow connected to the inlet end of the tubular barrel 24A and includes separate openings communicating with an atomizing fluid supply line 27 and a liquid fuel supply line 29.
Referring to FIG. 3 there is shown an arrangement of the alternate embodiment of the invention wherein one atomizing device 34A may be suitably sized to service a plurality of separate ignitor assemblies 83 each of which is associated with a different burner port 54 in furnace wall 52.
Referring to FIG. 4 there is shown a detail of the alternative embodiment of the invention comprising the liquid fuel fired ignitor 10A including a nozzle 12A having one end coupled to a body portion 14A and the other end fitted with a sprayer head 16A. The nozzle 12A extends through a guide tube 87 and a yoke assembly 96, the latter cooperates with the ignitor body portion 14A and the locking device 99 to provide a transition means whereby the ignitor 10A may be coupled and uncoupled from the liquid fuel connecting line 98. The yoke assembly 96 includes a passage 17 which cooperates with the passage 18A and the bore 26A to permit uninterrupted fuel flow through the ignitor 10A. The liquid fuel connecting line 98 has its outlet end connected to the yoke assembly 96 at passage 17 and its inlet end connected to the outlet end of tubular barrel 24A. The T-fitting 25 has one end connected to the inlet end of barrel 24A, its second end connected to the liquid fuel supply line 29 and its third end connected to a plug member 23, the aforementioned connections are preferably threaded in order to facilitate dismantling of the ignitor system for cleaning and maintenance.
The plug member 23 has an opening which admits an internally threaded tubular coupling A, the latter is connected at its inlet end to the atomizing fluid supply line 27. An inner tube 32A projects from within the coupling 30A into the tubular barrel 24A. The tube 32A has a closed outlet end and an open inlet end 38A, the, latter being threadably engaged with the outlet end of coupling 30A. The inner tube 32A discharges through a plurality of ports 36A into an annular passage 33A formed between the cylindrical walls of tubular barrel 24A and inner tube 32A. The ports 36A are circumferentially spaced about the cylindrical wall near the outlet end of tube 32A. The length of threading of the inlet end 38A provides a range of adjustment whereby the position of the ports 36A may be linearly shifted with respect to the inlet and outlet ends of the tubular barrel 24A. A lock nut A fixedly secures the tube 32A to maintain the selected position of the ports 36A with respect to the barrel 24A. The repositioning of the ports 36A is effected by uncoupling the plug member 23 from the T-fitting 25 and removing therewith the coupling 30A and associated tube 32A, thereafter, loosening the lock nut 40A and rotating the tube 32A within the coupling 30A to achieve the desired port location with respect to the tubular barrel 24A. When the repositioning of ports 36A is complete, the lock nut 40A should be tightened before recoupling the plug member 23 to the T-fitting 25.
During operation of the main embodiment of the invention, pressurized liquid, e.g., fuel oil, is admitted to the ignitor at opening and flows through passage 18 into the annular passage 33 where it is atomized by pressurized fluid, e.g., air, exiting from the inner tube 32 through the discharge ports 36. The liquid fuel is thereafter further atomized as it is serially conveyed through the orifice plates 42 and 44, the atomization resulting from impingement on the imperforate portions of plates 42 and 44, and the velocity increases experienced during passage through the orifice openings 46 and 48. A final stage of atomization occurs as the liquid fuel discharges through the openings 50 of sprayer head 16.
In the operation of the alternate embodiment of the invention, the supply line 29 delivers pressurized liquid, e.g., fuel oil, to the T-fitting for flow into the annular passage 33A. The supply line 27 delivers pressurized atomizing fluid, e.g., air, into the inner tube 32A. The liquid fuel flowing through passage 33A is atomized by the fluid discharging from ports 36A. The liquid fuel is thereafter further atomized as it is serially conveyed through the orifice plates 42A and 44A, the atomization resulting from impingement on the imperforate portions of plates 42A and 44A, and the velocity increases experienced during passage through the orifice openings 46A and 48A. The liquid fuel leaving the atom izing device 34A passes through a coupling 97 and a connecting line 98 for delivery to the ignitor 10A wherein there occurs a final stage of atomization as the fuel discharges through the openings 50A of sprayer head 16A.
In the operation of the atomizing device of the present invention, the atomizing fluid pressure at the inlet to the device will be at a higher value than that of the liquid fuel entering the device. The difference in pressure varies in accordance with the type of atomizing fluid and/or the type of liquid fuel to be atomized.
While in accordance with provisions of the statutes there is illustrated and described herein a specific embodiment of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of the other features.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
l. A liquid fuel fired ignition system comprising at least one ignitor. a device for atomizing the fuel preparatory to firing from the ignitor. said device including a nozzle having an inlet and an outlet end, a coupling connected to the inlet end, an inner tube disposed in said coupling and projectingv into the nozzle through the inlet end thereof, said tube cooperating with the nozzle to define therebetween an annular passage of uniform dimension throughout, said tube having an outlet formed of at least one port opening into the passage and an inlet formed with a threaded portion, a sleeve mounted in the coupling, said sleeve having a threaded portion engaging the threaded portion of the tube while permitting rotatable and axial adjustment of said tube, means for supplying a liquid fuel to the passage and an atomizing fluid to the tube, the fuel being atomized by the fluid discharging from said port, and a pair of spaced perforated dislks disposed within the nozzle downstream fuel flow-wise of said tube, the fuel being further atomized while passing through said disks.
2. The system according to claim 1 wherein the atomizing device is an integral part of the ignitor.
3. The system according to claim 1 wherein the atomizing device is separate from the ignitor, and including conduit means flow connecting the device to said ignitor.
4. The system according to claim 1 comprising a plurality of ignitors, said atomizing device being separate from the ignitors, and including conduit means flow connecting the device to said ig'nitors.
5. The system according to'claim 1 including a lock nut engaging the threaded portion of said tube to fixedly secure the tube to said sleeve thereby maintaining the tube in the selected position.
* l l -l l=
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1826776 *||Jul 20, 1928||Oct 13, 1931||Gunther Charles O||Liquid fuel burner and method of atomizing liquids|
|US3650476 *||Jan 16, 1968||Mar 21, 1972||Babcock & Wilcox Co||Liquid fuel burner|
|US3747860 *||Oct 26, 1971||Jul 24, 1973||Shell Oil Co||Atomizer for liquid fuel|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4049200 *||Apr 5, 1976||Sep 20, 1977||Sobol Jacob M||Nebulizer|
|US4726934 *||Sep 27, 1985||Feb 23, 1988||Cabot Corporation||Carbon black burner|
|US4988286 *||Mar 14, 1989||Jan 29, 1991||Electric Power Technologies, Inc.||Smokeless ignitor|
|US5289976 *||May 25, 1993||Mar 1, 1994||Mobil Oil Corporation||Heavy hydrocarbon feed atomization|
|US5603453 *||Dec 30, 1994||Feb 18, 1997||Lab S.A.||Dual fluid spray nozzle|
|US5636981 *||May 19, 1994||Jun 10, 1997||Lilly Engineering Company||Fuel oil burner|
|US6520767 *||Apr 25, 2000||Feb 18, 2003||Supercritical Combusion Corporation||Fuel delivery system for combusting fuel mixtures|
|US20160288075 *||Oct 3, 2014||Oct 6, 2016||Spraying Systems Co.||Catalytic cracking spray nozzle with internal liquid particle dispersion ring|
|EP0744999A1 *||Dec 29, 1995||Dec 4, 1996||Lab S.A.||Dual fluid spray nozzle|
|EP0744999A4 *||Dec 29, 1995||May 13, 1998||Lab Sa||Dual fluid spray nozzle|
|WO1996020790A1 *||Dec 29, 1995||Jul 11, 1996||Lab S.A.||Dual fluid spray nozzle|
|U.S. Classification||431/354, 431/175, 239/432, 239/431, 239/434|
|International Classification||F23D11/36, F23D11/10, F23D11/40, F23D11/24, F23D11/38, F23Q3/00|
|Cooperative Classification||F23D11/102, F23Q3/008|
|European Classification||F23Q3/00F, F23D11/10A1|