US3811816A - Acoustic flame detectors for steam generators - Google Patents

Acoustic flame detectors for steam generators Download PDF

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Publication number
US3811816A
US3811816A US00327429A US32742973A US3811816A US 3811816 A US3811816 A US 3811816A US 00327429 A US00327429 A US 00327429A US 32742973 A US32742973 A US 32742973A US 3811816 A US3811816 A US 3811816A
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United States
Prior art keywords
burner
flame
bandwidth
firebox
windbox
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00327429A
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English (en)
Inventor
N Whitman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US00327429A priority Critical patent/US3811816A/en
Priority to GB68374A priority patent/GB1415813A/en
Priority to NL7400983A priority patent/NL7400983A/xx
Priority to DE2403320A priority patent/DE2403320A1/de
Priority to IT19761/74A priority patent/IT1007064B/it
Priority to NO740264A priority patent/NO139065C/no
Priority to JP49011498A priority patent/JPS49105236A/ja
Priority to FR7402804A priority patent/FR2215583B1/fr
Application granted granted Critical
Publication of US3811816A publication Critical patent/US3811816A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/16—Systems for controlling combustion using noise-sensitive detectors

Definitions

  • 3,635,018 teaches location of a sensor directed toward .the interior of a gas turbine combustion liner and using filters to .reject unwanted noise in the 6,000 16,000 hertz band.
  • the detector In the Rowell patent, the detector .listens to sound inside the firebox which is fed by a single burner.
  • a sensor In the De Corso patent, it is suggested that a sensor can be employed for each of several combustion chambers, where the combustion chambers arenot interconnected'by cross-fire tubes.
  • one object of the present invention is to provide'an improved acousticflame detector system designed to detect the failure of one of a plurality of burners, particularly at low fuel flow and to shut off the fuel to the extinguished burner.
  • Another object of the invention is to provide an improved flame detector suitable for a steam generator having a plurality of closely disposed burners.
  • Still another object of the invention is to provide an improved method for detecting flame failure in an individual burner and shutting down the burner to prevent explosion.
  • FIG. 1 is a front elevation view of the lower part of a typical marine boiler.
  • FIG. 2 is a horizontal cross section of a typical fuel burner in such a boiler
  • FIG. 3 is a schematic block diagram of the probe amplifier and burner shutoff system
  • FIGS. 4a and 4b are graphs showing the decibel and the change in decibel level for one type of burner.
  • FIG. 5 is a graph showing the change in decibel level for a different type of burner.
  • the invention is practiced by locating a directional electroacoustical sensor in the air supply passage of each individual burner between a common windbox and a common firebox.
  • a relatively narrow frequency band of sound selected to give the greatest decibel difference between flame and no-flame conditions is monitored for each burner. Sound level below a selected threshold in a particular burner shuts off fuel to that burner.
  • FIG. 1 shows the lower front half of a marine boiler 1 having four individual burners designated 2, 3, 4 and 5.
  • Each burner has a removable fuel manifold assembly 6 and an air register handle 7 to control the flow of air betweenthe windbox and the firebox.
  • each burner also includes an acoustic probe 8, with shielded electrical leads 8a, arranged in a manner to be described in more .detail.
  • FIG. 2 of the drawing a typical marine burner assembly is shown. Although such burners may take many different forms according to the particular manufacturer, the burner shown is a Racer type manufactured by Babcock and Wilcox and will be used to describe theprinciple of the invention.
  • the manifold assembly 6, air register handle 7 and probe 8 are preferably mounted in a removable insulated cover plate 9 which is contained in the outer furnace wall 10. Spaced from the outer wall 10 is the inner or insulated firebox wallll provided with an opening 12 for each burner leading to a common fireboxv 13.
  • the space between outer wall l0and inner wall 11 is known in the art as the windbox. 14 and this is supplied with combustion air by a, suitable fan.
  • a controllable flow of air from windbox 14 to firebox 13 is selected by the setting of rotatable air register vanes 15 in accordance with the position of the airregister handle 7 by means of an interconnecting gear mechanism 16.
  • Liquid fuel and atomizing steam are fed to the spray nozzle 17 from the manifold 6.
  • a rotatable lever 18 allows the withdrawal of the supply housing 19 and the connected nozzle 17 for cleaning.
  • Additional means for controlling flame pattern such as a flame shield 20 and swirl vanes 21, vary with the type of burner and are not material 'to the present invention. However, all of the burners to which the present invention applies have a construction which allows the selective admission of air from a common windbox through an individual air admission passage along with the fuel into a common firebox.
  • an acoustic high temperature probe 8 is mounted in cover plate 9 by means of a bracket 22 and a suitable aperture 23.
  • the probe comprises an electroacoustical microphone in a hollow tube which extends through the windbox 14 'and terminates in a space 24 which is behind the burning fuel emitted from nozzle 17, but within the individual air supply passage controlled by register vanes portion 25 may be provided in one vane to allow it to rotate. Details for insertion of the probe will necessarily vary from one type of manufacturer to the other depending upon the air controlling means into chamber
  • the probe is selected to be resistant to the temperatures expected to be encountered near the burner and is also selected to be highly directional along the probe axis. If a more sensitive probe is desired, water or air cooling may be employed.
  • the probe is oriented so that it is directionally most sensitive toward the flame itself.
  • the probe should also be mounted and oriented to attenuate any extraneous unwanted noises which would tend to lower the overall sensitivity of the system.
  • FIG. 3 of the drawing shows a block diagram for two burners. Elements having comparable functions in FIGS. 2 and 3 have the same reference numbers. Probes 8 for a pair of burner openings 12 are shown to be located in the individual air passages 12 between the common windbox 14 and common firebox 13. Each probe is shown with a separate amplifier 31 connected to an acoustic .band filter 32 which is adjustable to pass a selected bandwidth of sound. Output from the filter passes to a threshold trigger network 33 which provides a signal when the sound level falls below a selectable value. The latter signal is adapted to actuate a burner fuel shutoff valve 34.
  • the electronic devices are conventional. Amplifiers and filters for this service are available from Bolt, Beranek & Newman and others.
  • the trigger circuit may be a conventional meter relay.
  • FIG. 4a illustrates the sound level in one-third octave bands as measured in decibels versus frequency in hertz for an industrial furnace burning No. 6 fuel using a burner supplied by Foster-Wheeler C0.
  • Curve 40 is the absolute sound level in decibels at various frequencies when the air atomizing steam and fuel are flowing into the burner but no flame is taking place.
  • Curve 41 illustrates sound level when the burner is ignited at a low rate of fuel flow and curve 42 when the burner is ignited at maximum fuel flow.
  • FIG. 4b corresponds to FIG. 4a, but shows the difference in decibels between the absolute sound level at no flame and the absolute sound level with flame.
  • curve 43 is a plot of the difference between curves 40 and 41 of FIG. 4a.
  • curve 44 is a plot of the difference between curve 40 and 42 of FIG. 4a.
  • a relatively narrow frequency band is selected as indicated on FIG. 4b by dashed lines 45, 46 encompassing a one-third octave band centered on a frequency of 500 hertz, where the difference in decibels between the flame and no flame shows a suitable value.
  • One-third octave bandwidths have been used in this example because of the ready availability of filters to pass this width band.
  • a suitable threshold level I08 decibels in the example shown, is selected as indicated at 47 on graph 4a.
  • the threshold trigger circuit 33 is arranged to actuate the burner fuel shutoff relay panel 34 when the signal falls below this level.
  • FIG. 5 shows a graph similar to FIG. 4!), but for a John Zink Co. experimental burner burning No. 6 fuel oil.
  • a one-third octave band might have been selected centered at 500 hertz instead a one-third octave band emcompassed by dashed lines 48, 49 centered about a frequency of 2,500 hertz is selected.
  • Curve 50 is the difference in decibels between flame and no flame for a maximum flow of fuel, while curve 51 is the corresponding decibel difference curve for a minimum flow of fuel.
  • a suitable signal difference for both of these fuel flow conditions is obtained at 2,500 hertz as indcated by the substantial coincidence of the curves 50, 51.
  • Plotting of curves similar to FIG. 4b and FIG. 5 is necessary in order to obtain the optimum selection of a frequency band and a frequency for a particular type of burner and a particular fuel.
  • the invention operates as follows. When all four burners are operating properly, the sound level for each burner is above the threshold level within the bandwidth of sound being amplified and passed by the filter. Interruption of flame at one of the burners causes the sound level to drop below the threshold and to actuate the relay to shut off fuel to the affected burner.
  • the remaining burners continue to function as long as common windbox and firebox, the probe location as' indicated enables the probe to distinguish the sound due to flame or no flame at an individual burner and to thereby control the fuel flow.
  • an acoustic detector system comprising:
  • said probe comprises a hollow tube extending across said windbox and terminating between said air register and said nozzle, said tube having an electroacoustical microphone disposed therein.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Combustion (AREA)
  • Regulation And Control Of Combustion (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
US00327429A 1973-01-29 1973-01-29 Acoustic flame detectors for steam generators Expired - Lifetime US3811816A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US00327429A US3811816A (en) 1973-01-29 1973-01-29 Acoustic flame detectors for steam generators
GB68374A GB1415813A (en) 1973-01-29 1974-01-07 Steam generators
DE2403320A DE2403320A1 (de) 1973-01-29 1974-01-24 Akustische flammendetektoren fuer dampfgeneratoren
IT19761/74A IT1007064B (it) 1973-01-29 1974-01-24 Rivelatori di fiamma di tipo acusti co per generatori di vapore
NL7400983A NL7400983A (de) 1973-01-29 1974-01-24
NO740264A NO139065C (no) 1973-01-29 1974-01-28 Flammeovervaakningsinnretning for en dampgenerator
JP49011498A JPS49105236A (de) 1973-01-29 1974-01-29
FR7402804A FR2215583B1 (de) 1973-01-29 1974-01-29

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00327429A US3811816A (en) 1973-01-29 1973-01-29 Acoustic flame detectors for steam generators

Publications (1)

Publication Number Publication Date
US3811816A true US3811816A (en) 1974-05-21

Family

ID=23276508

Family Applications (1)

Application Number Title Priority Date Filing Date
US00327429A Expired - Lifetime US3811816A (en) 1973-01-29 1973-01-29 Acoustic flame detectors for steam generators

Country Status (8)

Country Link
US (1) US3811816A (de)
JP (1) JPS49105236A (de)
DE (1) DE2403320A1 (de)
FR (1) FR2215583B1 (de)
GB (1) GB1415813A (de)
IT (1) IT1007064B (de)
NL (1) NL7400983A (de)
NO (1) NO139065C (de)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4538979A (en) * 1980-09-25 1985-09-03 Centre National De La Recherche Scientifique (Cnrs) Method of controlling a combustion flame
US5120214A (en) * 1989-11-13 1992-06-09 Control Techtronics, Inc. Acoustical burner control system and method
WO1998034067A1 (de) * 1997-02-04 1998-08-06 Siemens Aktiengesellschaft Brenneranordnung und verfahren zur aktiven dämpfung einer verbrennungsschwingung
US5813849A (en) * 1996-08-07 1998-09-29 John Zink Company, A Division Of Koch-Glitshc, Inc. Flame detection apparatus and methods
EP0935098A1 (de) * 1998-02-04 1999-08-11 John Zink Company Flammendetektionseinrichtung und Verfahren
US6164957A (en) * 1999-08-31 2000-12-26 Gte Internetworking Incorporated Transducer for gas flare pilot flame detection
US20100175384A1 (en) * 2009-01-15 2010-07-15 General Electric Comapny Optical Flame Holding And Flashback Detection
US20110232296A1 (en) * 2010-03-24 2011-09-29 General Electric Company Optical fuel nozzle flashback detector
US20130040254A1 (en) * 2011-08-08 2013-02-14 General Electric Company System and method for monitoring a combustor
US9188330B1 (en) * 2011-03-16 2015-11-17 Astec, Inc. Apparatus and method for mixing tube assembly
US9506646B1 (en) * 2011-03-16 2016-11-29 Astec, Inc. Apparatus and method for linear mixing tube assembly

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55110823A (en) * 1979-02-16 1980-08-26 Kobe Steel Ltd Controlling method of air ratio at combustion furnace
EP0428373A3 (en) * 1989-11-13 1991-08-28 Control Techtronics, Inc. Acoustical burner control system and method
DE4040745A1 (de) * 1990-01-02 1991-07-04 Gen Electric Aktive regelung von durch verbrennung hervorgerufene instabilitaeten

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2767783A (en) * 1952-09-09 1956-10-23 Scully Signal Co Sonic control for burners
FR1177801A (fr) * 1956-05-28 1959-04-29 Babcock & Wilcox France Perfectionnements aux dispositifs de contrôle de flammes

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4538979A (en) * 1980-09-25 1985-09-03 Centre National De La Recherche Scientifique (Cnrs) Method of controlling a combustion flame
US5120214A (en) * 1989-11-13 1992-06-09 Control Techtronics, Inc. Acoustical burner control system and method
US5813849A (en) * 1996-08-07 1998-09-29 John Zink Company, A Division Of Koch-Glitshc, Inc. Flame detection apparatus and methods
WO1998034067A1 (de) * 1997-02-04 1998-08-06 Siemens Aktiengesellschaft Brenneranordnung und verfahren zur aktiven dämpfung einer verbrennungsschwingung
EP0935098A1 (de) * 1998-02-04 1999-08-11 John Zink Company Flammendetektionseinrichtung und Verfahren
US6164957A (en) * 1999-08-31 2000-12-26 Gte Internetworking Incorporated Transducer for gas flare pilot flame detection
US20100175384A1 (en) * 2009-01-15 2010-07-15 General Electric Comapny Optical Flame Holding And Flashback Detection
CN101846317A (zh) * 2009-01-15 2010-09-29 通用电气公司 驻焰和回火的光学检测
US8752362B2 (en) 2009-01-15 2014-06-17 General Electric Company Optical flame holding and flashback detection
CN101846317B (zh) * 2009-01-15 2016-04-20 通用电气公司 驻焰和回火的光学检测
US20110232296A1 (en) * 2010-03-24 2011-09-29 General Electric Company Optical fuel nozzle flashback detector
US9188330B1 (en) * 2011-03-16 2015-11-17 Astec, Inc. Apparatus and method for mixing tube assembly
US9506646B1 (en) * 2011-03-16 2016-11-29 Astec, Inc. Apparatus and method for linear mixing tube assembly
US20130040254A1 (en) * 2011-08-08 2013-02-14 General Electric Company System and method for monitoring a combustor

Also Published As

Publication number Publication date
IT1007064B (it) 1976-10-30
NO139065B (no) 1978-09-18
JPS49105236A (de) 1974-10-04
FR2215583B1 (de) 1977-09-23
FR2215583A1 (de) 1974-08-23
GB1415813A (en) 1975-11-26
DE2403320A1 (de) 1974-08-01
NO139065C (no) 1978-12-27
NL7400983A (de) 1974-07-31
NO740264L (no) 1974-07-30

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