US3154724A - Combustion control system - Google Patents

Combustion control system Download PDF

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Publication number
US3154724A
US3154724A US143909A US14390961A US3154724A US 3154724 A US3154724 A US 3154724A US 143909 A US143909 A US 143909A US 14390961 A US14390961 A US 14390961A US 3154724 A US3154724 A US 3154724A
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United States
Prior art keywords
flame
detector
amplifier
ultraviolet radiation
combustion
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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
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US143909A
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English (en)
Inventor
Giuffrida Philip
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Electronics Corp of America
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Electronics Corp of America
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Publication date
Application filed by Electronics Corp of America filed Critical Electronics Corp of America
Priority to US143909A priority Critical patent/US3154724A/en
Priority to GB38065/62A priority patent/GB1014649A/en
Priority to CH1184562A priority patent/CH401323A/de
Application granted granted Critical
Publication of US3154724A publication Critical patent/US3154724A/en
Anticipated expiration legal-status Critical
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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
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements
    • F23N5/082—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2229/00—Flame sensors
    • F23N2229/14—Flame sensors using two or more different types of flame sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2229/00—Flame sensors
    • F23N2229/16—Flame sensors using two or more of the same types of flame sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements

Definitions

  • infrared radiations from the combustion flame have a fluctuating characteristic and lead sulphide sensing cells utilized in conjunction with a band pass amplifier arrangement tuned to pass a narrow band of frequencies corresponding to the most pr dominant flame fluctuation frequency of the type shown in the Cade patent, No. 2,811,711 provide excellent flame supervision systems.
  • infra red systems of detection are not completely suitable, as the infra red radiation emanates from the entire flame beyond in a flame fringe area so that discrimination between the several flames within the same combustion chamber is diflicult, if not impossible.
  • the individual flames may be more easily supervised by sensing a radiation source that is more localized, such as a source of ultraviolet radiation frequencies, which emanate only from the core of the flame.
  • a radiation source that is more localized, such as a source of ultraviolet radiation frequencies, which emanate only from the core of the flame.
  • ultraviolet radiation sensing is more reliable than other systems of flame detection as it is less subject to interference from radiation sources other than the flame itself.
  • complex control circuitries have been developed and proved to be reliable operating in conjunction with the infra red sensing systems, and accordingly it is an object of the invention to provide a novel and improved combustion control system that employs an ultraviolet detector in a manner to be compatible with existing combustion control circuitry that utilizes reliable, low fre quency narrow band pass amplifier control arrangements.
  • Another and more general object of the invention is to provide a novel and reliable combustion control sy tem which utilizes a flame sensing element sensitive to radiation of the ultraviolet range.
  • a combustion control system which employs a quantum detector sensitive to ultraviolet radiation in the flame being supervised.
  • the quantum detector may be disposed in a scanner arrangement so that it supervises both the pilot flame and the main flame in the combus tion system or it may supervise one flame while an infra red detector supervises another flame.
  • the preferred embodiment of the invention employs a. quantum detector 3,l54,?24 Patented @et. 27, l'gfid having two spaced electrodes between which an electrostatic field is periodically built up to a magnitude sufiicient to produce avalanche breakdown between the electrodes when an electron is freed from one electrode in response to ultraviolet radiation impingement on that electrode.
  • the electrostatic field build-up cycle is limited to a low frequency rate in the order of less than twenty-five cycles per second and in the preferred embodiment is created by a resistance capacitance network arrangement in which the values of the components are proportioned to achieve this desired maximum cycle frequency.
  • the output of the detector circuitry is coupled by a damped tuned circuit of predetermined frequency characteristics to a multi-stage band pass amplifier circuit that operates the main combustion control relay.
  • the amplifier-control relay circuitry is also compatible with infra red detector systems.
  • the system thus provides a versatile combustion supervision system which employs ultraviolet radiation detection circuitry as Well as infra red detection, and in which either type of detection may be used individually or together.
  • FIG. 1 is a schematic diagram of the scanner arrangement showing the main burner, the pilot burner and the scanner element disposed for supervising both the pilot flame and the main burner flame;
  • FIG. 2 is a schematic diagram of the ultraviolet radiation detection and band pass amplifier circuitry according to the preferred embodiment of the invention.
  • FIG. 1 there is shown in diagrammatic form a combustion system having a combustion chamber 10 which is supplied with a main fuel conduit 12 controlled by suitable valving (not shown).
  • a pilot burner 14, provided with suitable means for ignition provides a pilot flame 16 which extends out into the area in front of the main fuel conduit 12.
  • the fuel from the conduit 12 is ignited by the pilot flame to provide a main flame 18.
  • Mounted in the wall of the combustion chamber is a tubular arrangement 20 which may be aligned so that both the end of the pilot flame 16 and the main flame 18 may be supervised by the scanner element 22.
  • the scanner element in this embodiment is an ultraviolet sensing tube which includes a pair of parallel, spaced tungsten electrodes 2-4, 26 as indicated in FIG. 2, which are housed in an envelope 23 transparent to ultraviolet radiation that contains a suitable inert gas.
  • This scanner tube may be the commercially available McGraw-Edison ultraviolet radiation detection tube.
  • the scanner element 22 is connected in series circuit with a current limiting resistor fit ⁇ of 10K ohms to a circuit arrangement which periodically builds up an electrostatic field of suflicient magnitude between the electrodes 24, 26 to permit avalanche breakdown between the electrodes in response to bombardment of those electrodes by ultra violet radiation protons.
  • the electrostatic field control circuitry includes an 0.982 microfarad capacitor 3.2, a 470K ohm resistor 34, rectifying diode 36 and a high voltage transformer 38, which has a primary winding 4% to which a volt AC. input signal is applied and a secondary winding 42 connected between diode 36 and ground.
  • the electrical time constant of the circuitry is such that the circuit restores the charge on capacitor 31, to the operative level after each tube breakdown at a maximum rate of less than twentydive cycles per second.
  • the circuit time constant is .038 second and it requires approximately 1% time constants (.048 second corresponding to a maximum rate of twenty-one cycles) to reach the operative charge sassy 2a a primary winding of output transformer 46.
  • time constants .048 second corresponding to a maximum rate of twenty-one cycles
  • Capacitor d stores up the steep Wave front and pulse that resulted from the avalanche discharge of tube 22 and the resonant characteristic of this output circuit converts this energery into a low frequency (less than twenty-five cycles) sine wave signal that is inductively coupled by the secondary 52 of transformer 46 to terminals 54 and 5d of the control relay operating circuitry.
  • That circuitry includes a main transformer 53 which supplies a B+ signal to the anodes of amplifier tubes as and 62 through the filter network that includes registers 64-6, diode 6d and capacitors 76-72. A biasing signal is also applied at terminal 54 through resistor 74.
  • the input signal from the ultraviolet radiation detecting element 22 is coupled by capacitor '73 (which performs a DC. isolation function) and the resistor network including resistors lid and 81 to the grid of the fir" amplifier stage 64).
  • That stage is similarly arranged with a low pass (less than twenty-five cycles) capacitor feedback circuit which includes capacitors M, 96 and resistors 9i 1%.
  • the resultant amplified output pulse is coupled by capacitor W2 through a rectifying circuit that includes diode 164 so that only negative pulses are applied to the RC integrating circuit including resistor res and capacitor 1%.
  • the output of the integrating circuitry is applied to the main relay control circuitry in which tube 110 is normally conducting so that the resultant voltage drop across resistor 112 is sufficient to maintain the tube 114 in non-conducting condition.
  • tube llltl is driven out of conduction and the change in voltage at its anode is coupled to the grid of tube 114, so that tube 114 conducts and energizes the control relay 12%). This relay when energized indicated the presence of flame.
  • the secondary of transformer 55 has a plurality of taps, and in addition to supplying the 13+ potential it also supplies a voltage to the tube filaments 122, a voltage to the relay 12th, and a voltage to the relay control tube circuit.
  • a lead sulphide infra red radiation detector cell 124 may be used in certain combustion supervision applications where the ability to sense both infra red and ultraviolet radiation may be desirable.
  • a combustion system might supply pulverized coal as the main fuel with a gas fired pilot.
  • the detector 22 may be disposed to supervise the pilot flame 16 only and the cell 124 may be disposed in a separate arrangement to supervise the main flame 18.
  • the cell 12 may be connected in series with the secondary 52 of transformer 46 while a switch 125 in parallel with cell 324 permits the infra red detector to be removed from the circuitry. The switch might be operated in response to conventional programmer control, for example.
  • the invention provides a reliable band pass amplifier, combustion control relay arrangement operative at a low flame flicks frequency (the band pass filters have maximum signal pass characteristics at about 10 cycles per second, thus excluding steady state signals as well as power frequency signals and other signals which might cause erroneous operation), in combination with an ultraviolet radiation detector circuit, compatible with the band pass amplifier, which supervises the flame within a combustion system.
  • a combustion control system comprising a quantum W detector sensitive to ultraviolet radiation from a flame
  • said quantum detector being arranged to supervise flame in a combustion chamber, and including a pair of electrodes housed in an envelope transparent to ultraviolet radiation, means to energize said quantum detector so that said detector generates pulse signals at a predetermined frequency of less than twenty-five cycles persecond when flame is sensed by said detector, coupling means to couple a signal resulting from a breakdown between the electrodes in said quantum detector upon sensing of ultraviolet radiation from said flame, band pass amplifier means connected to said coupling means, the band pass characteristics of said amplifier including said predetermined frequency, and operating control means responsive to said amplifier for indicating the flame condition in said combustion chamber.
  • said detector energizing means includes a resistance capacitance circuit arranged to apply an electrostatic field to said detector electrodes at a frequency of.
  • said coupling means includes a damped resonant circuit tuned to provide an output signal having a principal frequency of less than twenty-five cycles per second in response to each breakdown of said quantum detector.
  • said damped resonant circuit include a primary winding of a transformer connected in series with said quantum detector and the series combination of a capacitor and a resistor connected in parallel with said primary winding.
  • a combustion control system for supervising a pilot flame and a main flame in a combustion chamber comprising a flame condition indication relay, a band pass amplifier being connected to said flame condition indicating relay to provide a signal to operate it, said amplifier being arranged to produce said relay operating signal in response to input signals within the frequency range of five to twenty-five cycles per second only, detector means having a pair of spaced electrodes disposed in an ionizable gas, said detector'adapted to be disposed to supervise an area within said combustion chamber, means to energize said detector means so that said detector means periodically generates pulse signals in response to avalanche breakdown of said ionizable gas when flame is sensed by said detector means, means to convert said avalanche breakdown pulses to an output signal having a major frequency component within said band pass frequency range, and means to apply said output signal to said band pass amplifier to operate said flame responsive relay.
  • said pair of electrodes are housed in an envelope transparent to ultraviolet radiation
  • said energizing means produces a high voltage electrostatic field between said electrodes at a frequency of less than twentyfive cycles per second and includes a high voltage source, a capacitor connected across said high voltage source, and a resistance connected in circuit between said capacitor and said high voltage source, the values of said resistor and said capacitor being proportioned so that the repetitive build-up of an electrostatic field of sulficient magnitude to enable an avalanche breakdown to be pro prised between said electrodes in response to ultraviolet radiation can occur at a maximum rate of twenty-five times per second.
  • said avalanche breakdown pulse converting means includes a transformer having a primary winding and a secondary winding, a resistance and a capacitance connected across said primary winding, providing in combination a damped resonant circuit for converting said avalanche breakdown pulse to said output signal, said primary winding being connected to said detector means and said secondary winding being connected to said band pass amplifier for coupling said output signal to said amplifier.
  • a combustion control system for supervising a pilot flame and a main flame in a combustion chamber comprising a flame condition indicating relay, a band pass amplifier being connected to said flame condition indicating relay to provide a signal to operate it, said amplifier being arranged to produce said relay operating signal in response to input signals within the frequency range of five to twenty-five cycles per second only, first detector means disposed to supervise a first selected portion within said combustion chamber, said first detector means being responsive to infra red radiation and producing a first output signal having a major frequency component corresponding to the major frequency component of the sensed infra red radiation, a second detector means disposed to supervise a second area within said combustion chamber, said second detector means providing an avalanche breakdown pulse when subjected to ultraviolet radiation, means to convert said avalanche breakdown pulse to a second output signal having a major frequency component within said band pass frequency range, and means to apply said first and second output signals to said band pass amplifier to operate said flame responsive relay.
  • said second detector means is a quantum detector that includes a pair of electrodes housed in an envelope transparent to ultraviolet radiation, means to produce a high voltage electrostatic field between said electrodes at a frequency of less than twenty-five cycles per second including a high voltage source, a capacitor connected across said high voltage source, and a resistance connected in circuit between said capacitor and said high voltage source, the values of said resistor and said capacitor being proportioned so that the repetitive build-up of an electrostatic field of suflicient magnitude to enable an avalanche breakdown to be produced between said electrodes in response to ultraviolet radiation can occur at a maximum rate of twenty-five times per second.
  • said avalanche breakdown pulse converting means includes a transformer having a primary winding and a secondary winding, a resistance and a capacitance connected across said primary winding, providing combination a damped resonant circuit for converting said avalanche breakdown pulse to said second output signal, said primary winding being connected to said second detector means and said secondary winding being connected to said band pass amplifier for coupling said second output signal to said amplifier.
  • a combustion control system comprising flame condition indicating means
  • band pass amplifier means connected to said flame condition indicating means to provide an indicating means operating signal
  • said amplifier means having a band pass characteristic so that it produces said operating signals in response to A.C. input signals in the audio and subaudio frequency range only and rejects power frequency signals,
  • input circuitry including detector means sensitive to flame, means to energize said detector means so that said detector means periodically generates pulse signals at a frequency substantially different than said power frequency and wtihin the band pass region of said amplifier when flame is sensed by said detector means,
  • said detector means includes a pair of spaced electrodes housed in an envelope transparent to ultraviolet radiation and said energizing means creates an electrostatic field between said electrodes, the breakdown of which produces said output signal.
  • sai-d electrostatic field creating means repetitively generates an electrostatic field between said detector electrodes at a frequency of less than twentyfive cycles per second when flame is sensed by said detector means.
  • said coupling means includes a damped resonant circuit tuned to provide an output signal having a principal frequency of less than twenty-five cycles per second in response to each signal resulting from a breakdown of the electrostatic field between said electrodes.
  • said damped resonant circuit includes a primary winding of a transformer connected in series with said detector means and the series combination of a capacitor and a resistor connected in parallel with said primary winding.

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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)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
US143909A 1961-10-09 1961-10-09 Combustion control system Expired - Lifetime US3154724A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US143909A US3154724A (en) 1961-10-09 1961-10-09 Combustion control system
GB38065/62A GB1014649A (en) 1961-10-09 1962-10-08 Combustion control system
CH1184562A CH401323A (de) 1961-10-09 1962-10-09 Einrichtung zur Überwachung oder Steuerung eines Brenners oder einer Feuerungsanlage

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US143909A US3154724A (en) 1961-10-09 1961-10-09 Combustion control system

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US3154724A true US3154724A (en) 1964-10-27

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3321634A (en) * 1964-08-17 1967-05-23 Babcock & Wilcox Ltd Photosensitive flame monitoring circuit
US3462652A (en) * 1964-07-01 1969-08-19 Philips Corp Radiation-responsive circuit arrangement
US3507333A (en) * 1967-10-23 1970-04-21 Xerox Corp Fire prevention system
US3548395A (en) * 1966-02-14 1970-12-15 Combustion Eng Flame condition sensing device
US3651327A (en) * 1970-08-25 1972-03-21 Electronics Corp America Radiation sensitive condition responsive system
US3739365A (en) * 1969-12-03 1973-06-12 Cerberus Ag Apparatus for detection of a fire or of flames
JPS5065940A (de) * 1973-10-12 1975-06-03
JPS559613B1 (de) * 1971-03-04 1980-03-11

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3142987C2 (de) * 1981-09-30 1984-08-02 LGZ Landis & Gyr Zug AG, Zug Vorrichtung zur Überwachung von Öl- und Gasflammen bei wahlweiser Verfeuerung von Öl oder von gasförmigen Brennstoffen

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2392895A (en) * 1942-02-27 1946-01-15 Light Control Inc Photosensitive tube
US2721276A (en) * 1952-11-19 1955-10-18 Honeywell Regulator Co Condition sensing apparatus
US2807008A (en) * 1956-05-08 1957-09-17 Scully Signal Co Fail-safe system and technique
US2811711A (en) * 1951-05-19 1957-10-29 Electronics Corp America Fire method and apparatus
US2879456A (en) * 1957-01-22 1959-03-24 Honeywell Regulator Co Condition responsive apparatus
US2911540A (en) * 1955-02-14 1959-11-03 Gen Controls Co Flame detection system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2392895A (en) * 1942-02-27 1946-01-15 Light Control Inc Photosensitive tube
US2811711A (en) * 1951-05-19 1957-10-29 Electronics Corp America Fire method and apparatus
US2721276A (en) * 1952-11-19 1955-10-18 Honeywell Regulator Co Condition sensing apparatus
US2911540A (en) * 1955-02-14 1959-11-03 Gen Controls Co Flame detection system
US2807008A (en) * 1956-05-08 1957-09-17 Scully Signal Co Fail-safe system and technique
US2879456A (en) * 1957-01-22 1959-03-24 Honeywell Regulator Co Condition responsive apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3462652A (en) * 1964-07-01 1969-08-19 Philips Corp Radiation-responsive circuit arrangement
US3321634A (en) * 1964-08-17 1967-05-23 Babcock & Wilcox Ltd Photosensitive flame monitoring circuit
US3548395A (en) * 1966-02-14 1970-12-15 Combustion Eng Flame condition sensing device
US3507333A (en) * 1967-10-23 1970-04-21 Xerox Corp Fire prevention system
US3739365A (en) * 1969-12-03 1973-06-12 Cerberus Ag Apparatus for detection of a fire or of flames
US3651327A (en) * 1970-08-25 1972-03-21 Electronics Corp America Radiation sensitive condition responsive system
JPS559613B1 (de) * 1971-03-04 1980-03-11
JPS5065940A (de) * 1973-10-12 1975-06-03

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Publication number Publication date
GB1014649A (en) 1965-12-31
CH401323A (de) 1965-10-31

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