US3732433A - Combustion control circuit for a fuel burner - Google Patents

Combustion control circuit for a fuel burner Download PDF

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Publication number
US3732433A
US3732433A US3732433DA US3732433A US 3732433 A US3732433 A US 3732433A US 3732433D A US3732433D A US 3732433DA US 3732433 A US3732433 A US 3732433A
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circuit
ignition
burner
flame
control circuit
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R Lourigan
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Webster Electric Co Inc
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Webster Electric Co Inc
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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
    • F23N5/20—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays
    • F23N5/203—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays using electronic means
    • 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
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/16—Measuring bridge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2227/00—Ignition or checking
    • F23N2227/12—Burner simulation or checking
    • F23N2227/16—Checking components, e.g. electronic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2227/00—Ignition or checking
    • F23N2227/36—Spark ignition, e.g. by means of a high voltage
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2229/00—Flame sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2231/00—Fail safe
    • F23N2231/10—Fail safe for component failures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2231/00—Fail safe
    • F23N2231/12—Fail safe for ignition failures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2239/00—Fuels
    • F23N2239/06—Liquid fuels
    • 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

  • a thermal switch is heated by a heater in the control circuit and opens to shut off the [52] U.S. Cl. ..307/117, 431/69, 431/74 burner motor, However, if ignition takes place, flame Int. CL. is detected within the predetermined period an im of Search l6, 1 17, 1 18, proved positively acting reliable resistance 307/119, 112; 431/24, 25, 2 69, flame detector circuit.
  • the flame detector circuit 27 serves to render nonconductive a silicon controlled rectifier in the control circuit in order to disconnect References Cited the thermal switch heater while maintaining operation UNITED STATES PATENTS of the burner motor.
  • the ignition circult is deenergized by a novel ignition disabling circuit 3,463,600 8/1969 Axmark ..307/1 17 X connected between the silicon controlled rectifier and 3.584.988 6/1971 Hirsbflmner et the ignition circuit.
  • Failure of the triac in a short cir- 3,624,407 ll/l97l Bauer ..307/1 16 Quit condition prevents an unsafe condition due to Primary ExaminerRobert K. Schaefer Assistant ExaminerM. Ginsburg Attorney-Richard D. Mason et al.
  • a conventional fuel oil burner heating installation of a type widely used in the past includes an ignition device such as a transformer or other ignitor for igniting fuel at the burner, together with a primary control using two or more relays for operating the burner in response to a thermostat.
  • an ignition device such as a transformer or other ignitor for igniting fuel at the burner
  • a primary control using two or more relays for operating the burner in response to a thermostat.
  • Objects of the present invention are to provide an improved combustion control circuit for controlling the operation of a fuel burner installation including a burner motor and an ignition circuit; to provide an improved combustion control circuit having desirable safety features including a novel arrangement for protecting against component failure; to provide an improved combustion control circuit in which the necessity for expensive components is reduced; to provide an improved, highly reliable flame detection circuit for use in a combustion control circuit; and to provide a combustion control circuit having an improved arrangement for discontinuing the operation of the ignition circuit when burner ignition is accomplished.
  • an improved combustion control circuit for an oil burner installation of the type including a burner motor and an ignition circuit.
  • a triac switching device is connected for simultaneously energizing both the burner motor and the ignition circuit.
  • a thermostat is located in the area to be heated by the oil burner installation, and a light sensitive variable resistance flame detector is disposed adjacent the fuel burner.
  • a control circuit operates to place the triac in a conductive condition to energize both the burner motor and the ignition device when the thermostat closes upon demand for heat. When ignition is accomplished, the control circuit operates in response to the flame detector for discon tinuing operation of the ignition circuit.
  • a thermal delay switch connected to the burner motor prevents further operation of the burner motor upon being heated to a predetermined extent.
  • a first heater in the control circuit operates from the time that the thermostat closes until such time as a flame is detected.
  • a second heater for the thermal switch protects against failure of the triac and heats the thermal switch at all times that the ignition circuit is in operation.
  • a novel flame detection circuit comprising a resistance bridge provided with a regulated operating potential and including a light sensitive variable resistance flame detector in one leg thereof. In the absence of flame the resistance bridge is maintained in an unbalanced condition. Upon the detection of flame, the resistance bridge is moved through the null point to an oppositely unbalanced condition, and the control circuit is operated positively and effectively.
  • An aspect of the invention resides in a novel circuit for disabling the ignition circuit in response to the detection of flame.
  • a transformer coupled between a switching device in the control circuit and a controlled conduction device in the ignition circuit enables or prevents operation of the ignition circuit in response to presence or absence of flame.
  • a relay and a light and light sensitive device are used.
  • FIG. 1 is a schematic and diagrammatic illustration of a combustion control circuit embodying the principles of the present invention.
  • FIGS. 2 and 3 are fragmentary schematic illustrations of alternative embodiments of the invention.
  • FIG. I of the drawing there is illustrated a combustion control circuit designated generally by the reference numeral 10 and constructed in accordance with the principles of the present invention.
  • the circuit 10 controls the operation of a typical oil burner installation including a burner 12, a burner motor 14 and an ignition circuit generally designated by the reference numeral 16.
  • the burner motor 14 and the ignition circuit 16 are operated upon a demand for heat by a burner circuit generally designated as 18 under the control of a control circuit generally designated as 20.
  • Demand for heat is signalled in conventional manner by a line voltage thermostat switch 22 or by a low voltage thermostat switch 24 located to sense temperature in a region heated by operation of the burner 12. In any given installation only one of the switches 22 or 24 is used, the other being replaced by a permanent closed circuit.
  • a flame detection circuit generally designated as 26.
  • the control circuit 20 serves to continue operation of the burner motor 14 while an ignition disabling circuit generally designated as 28 discontinues further operation of the ignition circuit 16.
  • a thermal delay device designated as a whole by the reference numeral 30 discontinues operation of the fuel burner installation.
  • the device 30 also discontinues operation of the installation in the event of certain undesirable malfunctions of components in the circuit 10.
  • the circuit includes a pair of power supply terminals 32 and 34 adapted to be connected to a standard nominal 115 volt, 60 hertz power supply.
  • the control circuit 20 and the flame detection circuit 26 are supplied with operating potential by means of a pair of secondary windings 36 and 38 of a transformer 40 having a primary winding 42 adapted to be coupled to the power supply terminals 32 and 34.
  • energization of the burner circuit l8 and the control circuit 20 can be interrupted by a conventional over-temperature limit switch and fan switch 44 and by operation of the thermal switch structure 30.
  • control of the energization of the burner circuit 18 is provided by a gated, bidirectional solid state controlled conduction device 46 in the form of a triac.
  • the output electrodes of triac 46 are in current supplying relation with both the burner motor 14 and with the ignition circuit 16.
  • triac 46 must be rendered conductive by coupling of its gate electrode to one of its output electrodes in order to bring about operation of the burner circuit 18.
  • FIG. 1 the combustion control circuit is illustrated in its normal, temperature satisfied condition wherein the thermostat switch 22 or 24 is open and wherein the triac 46 is in its high resistance or open circuit condition so that neither the burner motor 14 nor the ignition circuit 16 is energized.
  • a heating cycle is initiated under the control of the control circuit 20.
  • a safe start component check takes place, and assuming the circuit components to be operating properly, the control circuit serves to render the triac 46 conductive thereby simultaneously energizing the burner motor 14 and the ignition circuit 16 throughout a trial-for-ignition period having a duration determined by the operation of the thermal device 30.
  • control circuit 20 includes a pair of relay windings 48 and 50, which windings control a normally open set of relay contacts 52 connected in series with a resistor 54 and with the gate electrode of the triac 46.
  • Windings 48 and are arranged in known manner relative to contacts 52 through adjustment of variable resistances 49 and 51 respectively so-that energization of both windings is necessary to move or pull in the set of contacts from the open to the closed position, while energization of only the winding 50 suffices to hold the contacts in the tant features of the invention, the circuit 26 carries out a stable and reliable control operation despite such unfavorable factors as supply voltage fluctuations, intermittent or unstable ignition, intermittent extraneous light, or the like.
  • circuit 26 includes a zener diode 58 serving together with a resistor 60 to supply a voltage regulated driving signal to a resistance bridge 62.
  • Bridge 62 operates substantially independently of supply voltage variations.
  • Bridge 62 includes a pair of input terminals 64 and 66 connected across the zener diode 58 and a pair of output terminals 68 and 70 connected to the gate and cathode electrodes of the SCR 56 and shunted by a capacitor 72.
  • One leg of bridge 62 includes a variable resistance photoelectric device 74 disposed adjacent the burner 12. In the absence of flame the device 74 is in a high resistance condition, and when illuminated by the presence of flame the device 74 assumes a low resistance condition.
  • the remaining three legs of bridge 62 include resistances 76, 78 and 80 having values such that the bridge 62 is unbalanced in opposite directions when the device 74 is alternatively in its high and low resistance conditions.
  • the novel flame detection circuit 26 has important advantages in operation because it reliably and positively controls the condition of the SCR 56.
  • device 74 When no flame is present at burner 12, device 74 is in its high resistance condition and as a result the bridge 62 is unbalanced and bridge terminal 70 is maintained at a positive potential relative to bridge terminal 68. This potential appears across capacitor 72 in such a way as to maintain the gate electrode of the SCR 56 positive relative to its cathode. Accordingly, the SCR is maintained in condition for conduction of current through its output circuit.
  • Capacitor 72 provides asmoothing or filtering effect which prevents unwanted response of the flame detection circuit to various possible transient effects. Moreover, since the incident light level at device 74 must change substantially enough to change the condition of the bridge from one unbalanced condition to the oppositely unbalanced condition, positive and reliable operation is achieved. Furthermore, stability of operation is aided by the use of the zener diode 58 which provides a regulated driving voltage for the bridge 62 substantially independent of variations in the supply voltage.
  • the operation of the combustion control circuit 10 commences with a safe start component check.
  • switch 22 or 24 closes, a circuit is completed for energization of the control circuit 20 from the transformer 40.
  • the triac 46 is rendered conductive only if the components of the flame detection circuit 26 and control circuit 20 are operational. If the photoelectric device 74 provides a false indication of flame, the
  • SCR 56 is nonconductive and winding 48 cannot be energized to close normally open relay contacts 52. Similarly if SCR 56 is inoperative and cannot conduct current, winding 48 cannot be energized. The same result follows if because of any other fault the control circuit 20 or flame detector circuit 26 fails to operate.
  • windings 48 and 50 are energized. More specifically, winding 50 is energized at a continuous DC level by a diode 82 and capacitor 84 connected across secondary winding 38 in parallel with a resistor 86. Winding 48 is energized simultaneously by current flowing through the conductive SCR 56 and through a resistor 87 associated with the thermal delay circuit 30.
  • this circuit may take any desired form, and as illustrated includes a pair of spark electrodes 92 and 94 located in ignition relation to the combustible air fuel mixture at the burner 12.
  • the ignition circuit 16 is similar to the ignition circuit illustrated and described in detail in U. S. Pat. No. 3,556,706 Campbell, to which reference may be had for a more complete disclosure.
  • the circuit 16 includes a capacitor 96 which charges repetitively during alternate half-cycles of the power supply waveform through a diode rectifier 98, a resistance 100 associated with the thermal delay circuit 30, and an inductance 102.
  • a trigger circuit including a pair of voltage divider resistors 104 and 106 and a phase shift capacitor 108 applies an operating voltage to the gate electrode of an ignition circuit SCR 110.
  • the SCR 110 is placed in a conductive condition and rapidly discharges the capacitor 96 in a pulse or surge through the primary winding 112 of a transformer 114 having a secondary winding 116 connected to the spark gap electrodes 92 and 94.
  • the combustion control circuit carries out a trial-for-ignition operation during a predetermined time period the duration of which is established by operation of the thermal delay device 30. In normal operation, ignition takes place during this period. If ignition fails to occur, then continued emission of fuel from the burner 12 could create an undesirable and potentially unsafe condition. For this reason, the thermal delay device functions to shut down the burner motor 14 and the combustion control circuit 10 at the end of the trail-for-ignition period if ig' nition is not detected by the flame detecting circuit 26.
  • this device includes a normally closed set of switch contacts 118 controlling current flowing via the triac 46 to the burner motor 14 and ignition circuit 16.
  • Contacts 118 are controlled by a bimetallic switch actuator 120 which opens the contacts 1 18 when the actuator is heated to a predetermined extent.
  • the contacts are arranged so that they are latched open and cannot reclose until released by a service man or operator. Heating of the actuator 120 is carried out at a relatively high rate of thermal transfer by the resistor 87 in series with the relay winding 48 and the control circuit SCR 56. Heating at a slower rate is carried out by the resistor in series with the triac 46. The heat transferred to the actuator by the resistor 87 is such that contacts 1 18 open in about 30 seconds.
  • thermal delay device 30 may take various forms, one device highly suitable for the purpose is disclosed in U. S. Pat. application Ser. No. 204,491, filed Dec. 3, 1971, of Donald F. Dalziel and Charles H. Heide. Reference may be had to that application for a further description of the structure and operation of the device 30.
  • the heater resistor 87 is energized because it is in series with the relay winding 48. If ignition fails to occur within the predetermined time, contacts 118 open and deenergize the burner motor 14 and the ignition circuit 16. The burner installation remains shut down until such time as the cause for ignition failure is corrected and the contacts 118 are reclosed.
  • Ignition disabling circuit 28 includes a coupling transformer 122 having a primary winding 124 connected to the anode and cathode of the SCR 56 and a secondary winding 126 connected to the gate electrode and cathode of the SCR 110.
  • SCR 56 When SCR 56 is nonconductive, current flows through the primary winding 124 in half cycles when the ignition circuit 116 would otherwise operate, and the gate electrode and cathode of the SCR 110 are reverse biased. Due to this reverse bias the SCR 110 cannot be rendered conductive and no capacitor discharge takes place to produce ignition sparks. Conversely, when SCR 56 is conductive, it acts as a low resistance shunt of primary 124 to prevent reverse biasing of the ignition circuit SCR ll 10.
  • FIG. 2 illustrates an alternative ignition disabling circuit generally designated as 28A.
  • a relay winding 128 is energized by a DC potential produced by a diode rectifier 130 and capacitor 132 to close a normally open set of relay contacts 134. Closing of contacts 134 effectively connects the gate electrode of SCR 110 to its cathode and prevents firing of the SCR 110.
  • SCR 56 conducts, it provides a low resistance bypass of the winding 128 and contacts 134 remain open, permitting SCR 110 to operate in its normal fashion in ignition circuit 16.
  • FIG. 3 illustrates yet another alternative ignition disabling circuit generally designated as 288.
  • a light sensitive resistance 140 is coupled between the gate electrode and cathode of the ignition circuit SCR 110.
  • a lamp 142 is disposed to illuminate the resistance 140 and is connected across the output electrodes of the SCR 56. When SCR 56 conducts, it shunts the lamp 142 so that resistance 140 is-in its high resistance condition and the ignition circuit operates. When SCR 56 is biased to its nonconductive condition, the lamp 142 is energized to reduce the resistance of the device 142 and disable the ignition circuit.
  • the circuit includes novel structure to prevent against unsafe conditions arising from failure of the triac 46 in a short circuit condition wherein it remains conductive regardless of the control signal applied to its gate electrode. This is a common failure condition of such devices.
  • the burner motor is energized without any monitoring by the flame detector, and without control of the thermostat in some cases, giving rise to a highly undesirable and potentially unsafe condition.
  • the burner motor 14 and ignition circuit 16 are energized, and the control circuit 20 exercises no monitoring function. Moreover, the ignition circuit 16 is not disabled by the SCR 56 and the disabling circuit 28 or 28A. However, the continuously operating ignitioncircuit l6 draws current through the heater resistor of the thermal delay device 30. After a period of several minutes or so, the resistor 100 heats the actuator and the contacts 118 open to shut down the installation in a safe condition.
  • the present invention avoids this unsafe condition because if flame is not present and the thermal switch contacts open, current to the burner motor is positively discontinued without reliance upon the operability of the triac 46.
  • a control circuit for placing the triac in a conductive conditionto energize both the burner motor and the ignition device in response to operation of the thermostat;
  • a flame detector coupled to the control circuit for providing a flame indication in response to operation of the burner
  • thermal delay switch for disabling the burner motor in response to being heated to a given extent
  • a first heater connected in said control circuit for heating said thermal delay switch during the time period beginning with operation of the thermostat and ending with production of a flame indication
  • a switching means coupled to both the burner motor and the ignition device and operable to energize the burner motor and ignition device simultaneously;
  • a flame detector disposed adjacent the fuel burner to provide a flame indication
  • thermostatically controlled switch in the heated space movable to an operating position in response to a demand for heat
  • a first control means coupled to said switching means and to said thermostatically controlled switch for operating said switching means in response to movement of said thermostatically controlled switch to the operating position;
  • a second control means coupled to said ignition device and to said flame detector for discontinuing operation of said ignition device in response to a flame indication
  • thermal delay switch connected to the burner motor for preventing operation of the burner motor in response to being heated to a predetermined extent
  • a first heater adjacent said thermal delay switch and connected to said first and second control means for energization during operation of said first control means prior to operation of said second control means;
  • a second heater adjacent said thermal delay switch and connected to said ignition device for energization during operation of said ignition device.
  • said first control means including relay means having a winding means and having a contact means connected in controlling relation to said triac, and an SCR having output electrodes and a gate electrode, said thermostatically controlled switch being coupled to said output electrodes, and said flame detector being connected to said gate electrode.
  • said flame detector comprising a light sensitive variable resistor, a bridge circuit including said detector in one leg, means for driving said bridge with a regulated driv ing signal, and a capacitor coupled to the bridge output and to the gate electrode of the SCR.
  • said second control means comprising a coupling transformer connected between said flame detector and said ignition device.
  • said combustion control circuit of claim 5 said second control means comprising a lamp and light sensitive resistor connected between said flame detector and said ignition device.
  • a combustion control circuit for a fuel burner comprising:
  • control means for operating the burner in response to energization of the control means
  • a controlled conduction device including electrodes forming an output electrode pair and a control electrode pair;
  • said output electrode pair being coupled to said control means for controlling the energization thereof;
  • variable resistance flame detection device disposed in flame sensing relation to the burner
  • a resistance bridge having opposed input and output terminals and having one leg including said flame detection device and having three legs including only fixed resistance;
  • said bridge output terminals being coupled to said control electrode pair of said controlled conduction device.
  • said driving signal means including a zener diode.
  • a combustion control circuit for controlling a fuel burner installation including a burner motor and an ignition circuit of the type including an ignition circuit gated device periodically rendered conductive by a gating signal to create a burner ignition condition, said combustion control circuit including:
  • motor start means and motor hold means coupled to the burner motor for sequentially initiating and then maintaining operation of the burner motor
  • a normally conductive controlled conduction device including electrodes forming an output electrode pair and a control electrode pair;
  • said output electrode pair being coupled to said motor start means for controlling the energization thereof;
  • variable resistance flame detection device disposed in flame sensing relation to the burner
  • a resistance bridge having opposed input and output terminals and having one leg including said flame detection device
  • said bridge output terminals being coupled to said control electrode pair of said controlled conduction device for rendering said controlled conduction device nonconductive in response to detection of flame to disable said motor start means;
  • an ignition disabling circuit coupled between said output electrode pair and the ignition circuit gated device for disabling the gated device in response to detection of flame.
  • a triac having agate electrode and having output electrodes connected in current supplying relation between a power source and both said motor and said ignition circuit;
  • a capacitor connected to said bridge for storing a potential corresponding to the balance condition of the bridge
  • a controlled conduction device having a control electrode coupled to said capacitor for conduction in response to the absence of flame and for nonconduction in response to the absence of flame;
  • a relay having pull-in winding means and hold winding means and having a normally open set of contacts coupled to the gate electrode of said triac;
  • thermoelectric means including a thermostat for energizing said hold winding means and said controlled conduction device in response to a demand for heat;
  • said pull-in winding means being connected for energization by said controlling conduction device;
  • an ignition disabling means coupled between said controlled conduction device and the ignition circuit active element for disabling the active element in response to nonconduction of said controlled conduction device
  • a second heater for said thermal switch connected in circuit with said ignition circuit.
  • said controlled conduction device comprising an SCR.
  • said disabling means comprising a lamp and a light sensitive resistance.
  • a combustion control circuit for a fuel burner and for an ignition circuit including an ignition circuit SCR and including a gating circuit for periodically applying a gating signal to the cathode and gate electrodes of the ignition circuit SCR for producing an ignition condition, said combustion control circuit comprising:
  • control means for operating the burner in response to energization of the control means;
  • a solid state controlled conduction device having a control electrode and having output electrodes coupled to said control means for controlling the energization thereof;
  • a flame detection circuit coupled to the control electrode of said solid state controlled conductive device for rendering said device nonconductive in response to detection of burner flame;
  • an ignition disabling circuit coupled between said solid state controlled conduction device and said ignition circuit
  • said disabling circuit including a transformer having one winding connected across the output electrodes of the solid state controlled conduction device and having another winding connected across the cathode and gate electrodes of the ignition circuit SCR to reverse bias the ignition circuit SCR in response to nonconduction of said solid state controlled conductive device.
  • a combustion control circuit for a fuel burner and for an ignition circuit including an ignition circuit SCR and including a gating circuit for periodically applying a gating signal to the cathode and gate electrodes of the ignition circuit SCR for producing an ignition condition, said combustion control circuit comprising;
  • control means for operating the burner in response to energization of the control means
  • a solid state controlled conduction device having output electrodes coupled to said control means for controlling the energization thereof;
  • a flame detection circuit coupled to the control electrode of said solid state controlled conduction device for rendering said device nonconductive in response to detection of burner flame
  • said disabling circuit including a lamp connected across the output electrodes of the solid state controlled conduction device and a light sensitive resistance connected across the cathode and gate electrodes of the ignition circuit SCR to prevent gating of the ignition circuit SCR in response to nonconduction of said solid state controlled conduction device.

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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)
US3732433D 1972-05-25 1972-05-25 Combustion control circuit for a fuel burner Expired - Lifetime US3732433A (en)

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US25698172A 1972-05-25 1972-05-25

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US (1) US3732433A (cs)
JP (1) JPS4949230A (cs)
BE (1) BE799993A (cs)
CA (1) CA984026A (cs)
CH (1) CH566523A5 (cs)
DE (1) DE2326763A1 (cs)
FR (1) FR2186118A5 (cs)
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IT (1) IT985144B (cs)

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US3854056A (en) * 1973-11-09 1974-12-10 Electronics Corp America Burner control system
US3872320A (en) * 1973-09-12 1975-03-18 Lear Siegler Inc Furnace control circuit
US3892981A (en) * 1973-12-04 1975-07-01 Robertshaw Controls Co Electrical primary control system for furnaces
US3938937A (en) * 1973-12-07 1976-02-17 Johnson Service Company Fuel ignition control arrangement
US3938939A (en) * 1975-02-12 1976-02-17 Sundstrand Corporation Burner control system with secondary safety switch
US3947220A (en) * 1974-10-21 1976-03-30 Johnson Service Company Fuel ignition control arrangement
US3980420A (en) * 1975-07-03 1976-09-14 Emerson Electric Co. Burner control system for domestic gas range ovens
US4024412A (en) * 1975-02-07 1977-05-17 The Scott & Fetzer Company (France Division) Burner control system with primary safety switch
US4167389A (en) * 1977-11-02 1979-09-11 Emerson Electric Co. Oil burner primary control for interrupted ignition system
US4242081A (en) * 1979-03-05 1980-12-30 Emerson Electric Co. Oil burner primary control for interrupted ignition system
US4319873A (en) * 1979-04-12 1982-03-16 American Stabilis, Inc. Flame detection and proof control device
US4370125A (en) * 1980-10-01 1983-01-25 Emerson Electric Co. Control system for blue-flame oil burner
US4427363A (en) 1980-11-06 1984-01-24 British Gas Corporation Flame rectification detectors
US6662136B2 (en) * 2001-04-10 2003-12-09 International Business Machines Corporation Digital temperature sensor (DTS) system to monitor temperature in a memory subsystem
US20180306445A1 (en) * 2017-04-22 2018-10-25 Emerson Electric Co. Igniter failure detection assemblies for furnaces, and corresponding methods of detecting igniter failure
CN114459053A (zh) * 2022-02-08 2022-05-10 深圳市振邦智能科技股份有限公司 一种电子打火与火焰检测电路

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JPS5280292U (cs) * 1975-12-10 1977-06-15
EP0320082A1 (en) * 1987-12-08 1989-06-14 Desa International, Inc. Method and apparatus for a flame sensing digital primary safety control for fuel burning devices
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Cited By (17)

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Publication number Priority date Publication date Assignee Title
US3872320A (en) * 1973-09-12 1975-03-18 Lear Siegler Inc Furnace control circuit
US3854056A (en) * 1973-11-09 1974-12-10 Electronics Corp America Burner control system
US3892981A (en) * 1973-12-04 1975-07-01 Robertshaw Controls Co Electrical primary control system for furnaces
US3938937A (en) * 1973-12-07 1976-02-17 Johnson Service Company Fuel ignition control arrangement
US3947220A (en) * 1974-10-21 1976-03-30 Johnson Service Company Fuel ignition control arrangement
US4024412A (en) * 1975-02-07 1977-05-17 The Scott & Fetzer Company (France Division) Burner control system with primary safety switch
US3938939A (en) * 1975-02-12 1976-02-17 Sundstrand Corporation Burner control system with secondary safety switch
US3980420A (en) * 1975-07-03 1976-09-14 Emerson Electric Co. Burner control system for domestic gas range ovens
US4167389A (en) * 1977-11-02 1979-09-11 Emerson Electric Co. Oil burner primary control for interrupted ignition system
US4242081A (en) * 1979-03-05 1980-12-30 Emerson Electric Co. Oil burner primary control for interrupted ignition system
US4319873A (en) * 1979-04-12 1982-03-16 American Stabilis, Inc. Flame detection and proof control device
US4370125A (en) * 1980-10-01 1983-01-25 Emerson Electric Co. Control system for blue-flame oil burner
US4427363A (en) 1980-11-06 1984-01-24 British Gas Corporation Flame rectification detectors
US6662136B2 (en) * 2001-04-10 2003-12-09 International Business Machines Corporation Digital temperature sensor (DTS) system to monitor temperature in a memory subsystem
US20180306445A1 (en) * 2017-04-22 2018-10-25 Emerson Electric Co. Igniter failure detection assemblies for furnaces, and corresponding methods of detecting igniter failure
CN114459053A (zh) * 2022-02-08 2022-05-10 深圳市振邦智能科技股份有限公司 一种电子打火与火焰检测电路
CN114459053B (zh) * 2022-02-08 2023-10-17 深圳市振邦智能科技股份有限公司 一种电子打火与火焰检测电路

Also Published As

Publication number Publication date
CA984026A (en) 1976-02-17
BE799993A (fr) 1973-09-17
GB1428819A (en) 1976-03-17
FR2186118A5 (cs) 1974-01-04
DE2326763A1 (de) 1973-12-06
IT985144B (it) 1974-11-30
CH566523A5 (cs) 1975-09-15
JPS4949230A (cs) 1974-05-13

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