Abstract: A method of operating a cooktop appliance includes inputting a temperature measurement and a set temperature into a closed-loop control algorithm. When the output of the closed-loop control algorithm is less than a power level threshold, a first control valve to a gas burner of the cooktop appliance is closed.

Abstract: A cooktop appliance includes a user interface, a gas burner, and a temperature sensor. A manually adjustable primary control valve is coupled to the gas burner. A secondary control valve is connected in series between the manually adjustable primary control valve and the gas burner. A controller is in communication with the secondary control valve. The controller is configured to adjust the secondary control valve in response to a user-determined set temperature, a temperature measurement from the temperature sensor, and a determined position of the manually adjustable primary control valve.

Abstract: A gas cooking appliance is disclosed that according to one embodiment includes at least one gas burner and a gas tap. The gas tap includes a gas inlet conduit and at least one gas outlet conduit suitable for conducting gas to the gas burner. An injector arranged fixed to the outlet conduit, the outlet conduit being in fluid communication with the injector with the injector providing an outlet for the gas flow to the burner. The injector includes at least two outlet holes for the exit of gas to the burner, with each outlet hole having a respective outlet mouth.

Abstract: A gas tap for a gas burner that includes a gas inlet conduit for the entry of gas at a nominal pressure, at least one outlet conduit suitable for conducting gas to the burner through an outlet hole, and a rotating regulating element for regulating the incoming gas flow from the inlet conduit to the outlet conduit. The outlet conduit conducting a variable flow rate gas flow to the outlet hole when the regulating element rotates along an angular path. The gas tap also includes at least one constant flow outlet conduit for conducting a minimum constant flow rate gas flow (Qc) at nominal pressure (Pn) to the burner through a constant flow outlet hole when the regulating element rotates along the angular path.

Abstract: A signal conditioner for use with a controller and a burner receives an input signal from the controller. A conversion circuit generates a primary output signal corresponding to the input signal to control the burner. The signal conditioner also includes a delay circuit. The delay circuit overrides the primary output signal generated by the conversion circuit and substitutes a delay signal to the burner at a predetermined level for a predetermined time. The signal conditioner may also include a temperature override circuit, which receives a temperature of air from the burner. If the temperature is above or below established limits, the temperature override circuit substitutes a temperature override signal to the burner.

Abstract: The present invention refers to a combustion system applied in cooking equipments, which comprises technical features capable of enhancing heat exchange efficiency and capacity of cooking equipments through a turbulent combustion regime process. Preferably, the combustion system in accordance with the present invention comprises a fuel feed duct (1) connected to a cooking equipment burner (2) by means of an intermittent mechanism (3) for the purpose of releasing and blocking the fuel flow coming from said feed duct (1) such that an ignition element (4) causes a fuel turbulent combustion in said burner (2).

Abstract: An ignition control system for an appliance is disclosed. The appliance includes a gas burner, a user actuable valve for controlling a flow of fuel to the burner and an electrical resistance igniter for igniting fuel at the burner. The system includes a user actuable control interface having an off state and an on state, coupled to the valve operative to control the valve and provide a control signal indicative of the state of the control interface. The system also includes a controller having a timer circuit responsive to the control signal and a boost circuit coupled to the timer circuit. The timer circuit selectively activates the boost circuit for a predetermined period of time. A first DC power supply is selectively coupled to the igniter to provide power to the igniter through the boost circuit. A second DC power supply is coupled to the igniter and control interface.

Abstract: A signal conditioner for use with a controller and a burner receives an input signal from the controller. A conversion circuit generates a primary output signal corresponding to the input signal to control the burner. The signal conditioner also includes a delay circuit. The delay circuit overrides the primary output signal generated by the conversion circuit and substitutes a delay signal to the burner at a predetermined level for a predetermined time. The signal conditioner may also include a temperature override circuit, which receives a temperature of air from the burner. If the temperature is above or below established limits, the temperature override circuit substitutes a temperature override signal to the burner.

Abstract: A cooking stove that prevents the execution of a process such as ignition of a burner when a touch switch changes from a non-sensing state to a sensing state. In STEP201, when a first touch switch, which is one of the touch switches provided in an operation, is turned on from off, the process advances to STEP202, where a controller provided in a cooking stove main body starts a 1-second timer. The controller executes a loop composed of STEP203 and STEP210. When a second touch switch, which is one of the touch switches and is different from the first touch switch, is turned on from off in STEP210 before the 1-second timer times up in STEP203, the process advances from STEP210 to STEP211. The controller performs “error reporting” by blinking a display portion and activating a buzzer.

Abstract: The system (1) for controlling the combustion (7) of a cooking oven burner (2), comprises in combination a thermostat valve (3) with a rotary hand knob (4) and a non-electric temperature sensor (6) for modulating the burner flame (7), and an electromagnetic safety valve kept open for ignition, and a electronic module (10) supplying in a first moment a DC power supply to the safety valve (8), which is then maintained open by a thermocouple (9) heated by the main flame (7). A common electrode (18) is provided both for electronic flame detection and ignition. During the burner pre-ignition step, the absence of flame detection signal (If) permits the gas flow (G) to be cut off after a short timed interval, irrespective of the thermocouple response. In the event of the AC power supply being cut off, the thermocouple (9) and the thermostat valve (3) keep the burner modulated independently.

Abstract: A safety circuit 31, which compulsorily closes an on-off valve for supplying a gas to a burner when a microcomputer for performing a combustion control is in an abnormal condition, does not operate unless abnormality occurs to the microcomputer 1, and therefore even when the safety circuit 31 is out of order, an ignition operation is performed as it is. A transistor 4 is not turned off until a fixed time elapses from a start of an ignition sequence in the safety circuit 31, but the fixed time is shortened by a timer acceleration circuit 32, and if the transistor 4 is turned off by a transistor 2 being turned on, the safety circuit 31 is determined as normal, so that the normal ignition sequence is executed thereafter.

Abstract: The present invention is directed to an oil burner system having an electric cord set coupled between a controller and a valve associated with a pump. The electric cord set is operable to activate a solenoid valve associated with the pump for delivery of fuel oil to a nozzle of the burner. The electric cord set comprises a voltage or temperature independent timer circuit operable to activate the solenoid valve a predetermined period of time after a call for ignition signal is generated by the controller, wherein the predetermined time period is substantially constant with respect to variations in line voltage or in an ambient temperature in which the oil burner system resides.

Abstract: A water heater control system that prevents the accumulation and accidental ignition of dangerous quantities of unwanted flammable vapors. The system intermittently generates a spark at a predetermined interval such that if unwanted flammable vapors are present, they are burned in a controlled manner. The system obviates the need for flammable vapor sensors.

Abstract: A device for obtaining rapid ignition of a gas burner of a cooking hob fed via a gas pipe provided with a solenoid safety valve, with said burner there being associated a usual igniter and a knob for controlling its activation, the solenoid valve being connected to powering means immersed in the flame generated by the burner to maintain the solenoid valve in a working position which ensures gas feed to the burner, further powering means being provided to maintain said solenoid valve in said working position immediately a user activates the burner by means of the knob, without any further action on the knob by said user.

Abstract: A programmable burner for gas stoves, which is constituted by a gas burner and a safety valve that includes a thermocouple, which is located in coincidence with an external edge of the burner. The safety valve is maintained open when the thermocouple is detecting the presence of a flame on the gas burner and is closed when the burner has been turned off. An electrode is placed near of the external periphery of the burner for igniting. A spark generation module is connected with the electrode for generating the sparks for igniting the burner. A spark interrupter is connected to the spark generation module, the spark interrupter being located over a burner knob that is connected to the safety valve, for activating or deactivating the spark generation of the spark generation module. Finally a programmable device is connected with the thermocouple and the security valve, for programming the ignition time of the burner in accordance with a preestablished operation time by user.

Abstract: An oil burner control system is disclosed in which an extended time may be temporarily selected, in situations such as initial set up or periodic maintenance, for priming the pipes, filters and pumps, before a safety lockout of system operation occurs, while otherwise leaving the normal safety lockout functions intact. An igniter in the system operates in an “intermittent” mode during the temporarily selected extended time, and otherwise operates in an “interrupted” mode.

Abstract: An ignition system for a gas appliance comprises an ignitor for igniting gas, a gas valve which controls the flow of gas to the ignitor, and a delay switch which delays the opening of the gas valve. The delay switch comprises a piston and a cylinder which define a chamber. The piston moves between a first position and a second position in the cylinder. The piston is coupled to the gas valve such that when the piston reaches the second position, the gas valve is opened. The chamber includes a large aperture and a small aperture which influence the rate at which the piston moves. The large aperture includes a sealing member which seals the large aperture when the piston moves from the first position to the second position to resist the motion of the piston. The large aperture is opened when the piston moves in the other direction. The delay switch is connected to the ignitor such that when the ignitor is turned on, the piston moves against air resistance and delays the opening of the gas valve.

Abstract: The present invention pertains to a present atomizing type burner (1) for an engine independent heating system in a vehicle, comprising a pump (2) for feeding liquid fuel (4) through the fuel pipe (5) to the spray nozzle (3), a ventilator (6) for feeding combustion air (7) to the combustion chamber, an electric motor (9) for driving both the fuel pump (2) and the ventilator (6), and an igniting device (10) for firing the air-fuel mixture in the combustion chamber (8). The invention suggests that the system be fitted with a voltage and speed regulator (11) for the electric motor (9), as well as a device for regulating the fuel pump (2) pressure after the heating system has ignited and the flame has become stable.

Abstract: The present invention provides an external burner shut-off for oil fired heating systems. More specifically, the present invention provides a burner control circuit interrupt for a burner control circuit. The interrupt includes a pair of switches controlled by a relay coil. One of the switches opens the power supply to the burner control circuit and the other switch provides power to a timer circuit of the interrupt. The timer circuit counts down from a predetermined time to allow sludge in an oil holding tank to resettle after an oil delivery. The interrupt provides a fail-safe feature to insure that the burner control circuit is not inadvertently interrupted.

Abstract: A flame ionization detector having a pair of spaced electrodes to which a DC voltage is applied and a flame produced between the electrodes by burning a gas whose composition is to be determined, thereby ions are produced which form an ion current between the electrodes which is representative of the gas composition to be measured. The flame detector is formed by a base plate having a first channel for inlet of the gas whose composition to be measured, a second channel for inlet of a combustion gas, a third channel connected to the first and second channels for conveying a mixture of the gases to an outlet communicating with a nozzle outlet in a ceramic plate on the base plate which faces an opening in a metal plate spaced at a predetermined distance from the ceramic plate such that the flame burns in the opening in the metal plate. An electrically conductive metal layer is disposed on the ceramic plate around the nozzle outlet therein.

Abstract: A direct spark ignition control system is provided for controlling for a gas fireplace burner. A solenoid is operatively controlled for supplying gas to the gas fireplace burner. A high voltage spark ignition circuit is operatively controlled for generating ignition sparks near the gas fireplace burner. A flame sensing circuit coupled to the gas fireplace burner provides a feedback signal to activate and deactivate the high voltage spark ignition circuit. A timing and control circuit provides a control signal to energize the solenoid and provides a control signal to deactivate the high voltage spark ignition circuit and a control signal to deenergize the solenoid after a set time period with the burner flame feedback signal activated.

Abstract: Roofing kettle apparatus for heating asphalt includes a wheeled chassis mounting a vat and a heating system for heating the vat. The heating system includes a solenoid operated valve for controlling the flow of fuel gas from a fuel gas source to each of a pair of burner nozzles and a igniter assembly having an outlet adjacent the outlet of a first combustion chamber. An igniter generates a spark to ignite gas discharging from the igniter assembly outlet. A flame sensor adjacent to the first combustion chamber outlet end senses the burning of fuel gas. The igniter assembly has a second outlet adjacent the second combustion chamber outlet end. The ignition of fuel gas discharging from the igniter assembly ignites the gas discharging through the combustion chamber outlets. The burners extend into the combustion chambers.

Abstract: In a gas appliance, such as a domestic gas fire or heater, there is provided a gas ignition device comprising a solenoid actuator which is electrically operable to cause a gas valve to initiate a gas flow, an igniter which is electrically operable to ignite the gas flow, and a remote control unit connected to the gas actuator and the igniter by a low voltage line. The control unit incorporates a power supply for providing a low voltage output and a timer circuit for applying the low voltage output to the line by actuation of a relay to cause gas ignition in response to manual actuation of a switch. Such a gas ignition device is advantageous because the remote control unit can be mounted at some distance from the appliance so that none of the circuit components of the remote control unit is subjected to high temperature in use, and there is no requirement for a high voltage supply to the appliance itself and only low voltages are supplied to the inside of the appliance.

Abstract: An ignitor includes a first transistor, a transformer, an ignition member, and a switching control member. The first transistor is activated in accordance with supply from a DC power supply to perform switching. The transformer has a primary winding through which a switching current flows via the first transistor, a secondary winding for generating high voltage when the switching current flows through the first winding, and a tertiary winding for generating a control output for controlling the switching of the first transistor in accordance with the high voltage generated in the secondary winding. The ignition member ignites a target object using the high voltage generated in the secondary winding of the transformer. The switching control member prolongs the ON time for the switching of the first transistor in accordance with a decrease in at least one of the ambient temperature and the power supply voltage.

Abstract: The invention concerns a gas-heated apparatus, in particular a cooking appliance with at least one glass ceramic cooking surface with a gas heating means of conventional configuration and two mutually independent safety paths for monitoring the electronic control device. The one safety path monitors actuation for each consumer while the other safety path monitors the flow of current through said consumer. The control device can be of a particularly simple structure by virtue of being designed in the form of a digital circuit. The consumers to be monitored are the solenoid valves and/or gas burners.

Abstract: A gas burning power supply section 10 for igniting gas includes a secondary battery and a solar battery for charging the secondary battery, and the operating voltage from the power supply section 10 is supplied to a gas ignition circuit 30, a flame detection circuit 50 for detecting the flame after the gas is ignited, and a solenoid valve-controlling timer circuit 60 for controlling the gas supply. A day/night discrimination circuit 100 is provided in association with the power supply section 10, and the ignition circuit 30, the flame detection circuit 50 and the timer circuit 60 are individually set in operation in accordance with a day/night discrimination output during the nighttime. In the event the flame of burning gas goes out halfway, the timer circuit 60 operates to perform a trial including reigniting operation, and if the reigniting fails during a trial period, the gas supply is automatically shut off.

Abstract: A burner control provides a pulsed flame sequence in response to a user's selective manipulation of an actuator through a range of response. A microcontroller-based control module switches both a burner ignitor control and an electric valve for gas supply to the burner in a predetermined time sequence depending upon the actuator position within the predetermined range. Preferably, one or more of a plurality of burners on a single cooking top are controlled for pulsed sequence operation, and a single actuator for each channel, preferably in a form of a rotary knob, provides a simple user interface for utilizing the pulsed flame sequence, preferably in a low gas flow or simmer cooking range.

Abstract: A combustion heater system for use in a moter vehicle has a combustion chamber housing a combustion pad which is heated by a pre-glow plug for vaporizing a fuel that is supplied from a fuel tank through a solenoid-operated valve to the combustion pad. The combustion chamber is supplied with air from a fan, and houses a spark plug for producing sparks in the combustion chamber to ignite a fuel vapor emitted from the combustion pad. The combustion heater system has a control unit which energizes the pre-glow plug to heat the combustion pad, actuates the solenoid-operated valve to supply the fuel to the combustion pad, and actuates the fan to supply air to the combustion chamber. The control unit subsequently energizes the spark plug to produce sparks upon elapse of a preset period of time hereby to ignite the fuel vapor emitted from the combustion pad for producing flames in the combustion chamber.

Abstract: A gas burning fireplace having a burner for producing a flame. A rod in the vicinity of the burner. A gap between the burner and the rod and wherein a flame is produced in the gap. An apparatus for monitoring the presence of a flame including a battery for applying a DC voltage between the rod and the burner. An electric circuit means for sensing a DC current between the rod and the burner.

Abstract: A gas flow detection device having an inlet for connection to a source of gas and an outlet for connection to a gas-using appliance is disclosed. Gas for feeding a pilot flame of the appliance flows through a permanently open orifice. When the appliance is switched on the pressure at the devices outlet drops and a piston which is in a tube is lifted by gas pressure at the device's inlet. Gas then flows from the inlet to the outlet. A light source and a light sensitive cell provide a signal that indicates that the piston has lifted. A monitoring system which makes use of the signal provided by the cell is also disclosed.

Abstract: A spark ignition system for a heater-type ignitor is disclosed. Current through the ignitor is transformed into a voltage which is utilized to operate a timing circuit which, in turn, causes operation of a valve permitting the flow of fuel to a burner. Operation of the valve can occur only after the expiration of a predetermined period of time during which the voltage applied to the ignitor and the current passing therethrough are continuously monitored thus ensuring that the ignitor has reached the ignition temperature of the fuel before the valve is permitted to open.

Abstract: A kerosene heater having a vertically oriented wick (4) which is movable to an upper position to be ignited, to a lowered position to be extinguished, and to any of a range of intermediate positions for continuous combustion, incorporates an apparatus (6A) operable by actuating a lever (6) to raise the wick to the upper position and initiate ignition and to lower the wick from that position, and an apparatus coupled thereto for automatically lowering the wick to a predetermined position within the combustion range after a predetermined time interval has elapsed following the start of igniting the wick. The danger of excessive flare-up of the wick flame after ignition is thereby eliminated, without the need for observation and control of the heater by the user.

Abstract: A spark ignition system for a heater-type ignitor is disclosed. Current through the ignitor is transformed into a voltage which is utilized to operate a timing circuit which, in turn, causes operation of a valve permitting the flow of fuel to a burner. Operation of the valve can occur only after the expiration of a predetermined period of time and the presence of a predetermined minimum voltage to the ignitor thus ensuring that the ignitor has reached the ignition temperature of the fuel before the valve is permitted to open.

Abstract: A low cost hot surface ignition system particularly adapted for use in gas furnaces and the like, the system including low voltage control and timing circuitry effective to control a gas valve and high voltage ignition circuitry incorporating a hot surface silicon carbide igniter disposed in the path of incoming gas and in the heat of the flame when ignition is achieved to effect flame rectification resulting in flame sensing. The system also provides fail-safe operation or safety shutdown of the associated furnace if ignition is not achieved or in the event of a failure of a component of the system.

Abstract: A plurality of burners are provided for burning a combustible gas mixture. A conduit extends to each of the burners for supplying a combustible gas mixture thereto. A mixing device is coupled between the conduit and a source of air and a source of combustible gas for mixing combustible gas and air for flow to the conduit. An air valve is coupled between the source of air and the mixing device for controlling the flow of air to the mixing device. First and second gas valves are coupled between the source of combustible gas and the mixing device. A control circuit is provided which is adapted to be operated in a flame intensity cycle of high/low flame or in a burner on/off cycle. In the flame intensity cycle, flow of air through the air valve is cyclically increased and decreased and gas flows continuously through the second gas valve for cyclically increasing and decreasing the flame intensity at each of the burners.

Abstract: A control system including a valve for controlling the flow of fuel to a burner, a resistive heater element connected between first and second terminals and disposed for igniting fuel emanating from the burner, an isolation transformer comprising a heater secondary winding connected to the first and second terminals so as to provide heating current to the heater element, and an electrode spaced from the heater element in a zone occupied by flame emanating from the burner. Also included is a start-up circuit for opening the valve to provide fuel to the burner for ignition by the heater element and a flame sensing circuit comprising an ac source, coupling means connecting the ac source means between the electrode and one of the first and second terminals with the secondary winding connected to the first and second terminals, and a detector circuit for detecting the flow between the electrode and the heater element of current conducted by flame in the zone.

Abstract: A power burner adaptable for use in conjunction with a wood burning stove employs a blower to produce a forced flow of air and a fuel valve which provides selective fuel communication with a fuel nozzle. Forced air and fuel is mixed in the nozzle and propelled through the nozzle outlet along a generally unidirectional exit path. A target is spaced from the nozzle outlet and interposed in the exit path. A heating assembly which is spaced from the target heats the target to a temperature sufficient to ignite the mixture traversing the exit path. A blast tube surrounds the target and forms an axially extending passageway which functions as a combustion chamber and a passageway for propelling the combusted fuel through an outlet opening of the blast tube. The burner is automatically controlled by an electronic controller.

Abstract: An operation control apparatus, in a combustion device, comprising an operation member (4) selectively settable at a stop position (A), an ignition position (B) or an open position (C); an electric member (10) and/or (15) which is energized by an electric power source (20) when the operation member is set in its ignition position; and a limited time operation circuit for affecting the operation of the electric member (10 and/or 15), either by itself energizing the electric member or by enabling the electric member to be energized by the power source (20), for a predetermined period of time. In the apparatus disclosed, the limited time operation circuit is inoperative for affecting the operation of the electric member (10 and/or 15) while the operation member (4) is set in its ignition position (B) and the electric member is energized by the power source (20).

Abstract: A gasified liquid fuel combustion apparatus which includes a gasifier in which liquid fuel is heated and gasified and delivered to a burner for combustion. A nozzle provided at the outlet of the gasifier is opened and closed by a valve needle operated by a solenoid. A solenoid control circuit includes first and second rectifying circuits between a power supply and the solenoid. A normally closed switch which is opened by a timer circuit is between the power supply and the first rectifying circuit, and a voltage reducing transformer is between the power supply and the second rectifying circuit. The first and second rectifying circuits are connected to a common output line so that a high DC voltage is supplied to the solenoid when the normally closed switch is closed and a low DC voltage is supplied to the solenoid when the normally closed switch is open.

Abstract: A combustion control apparatus which controls combustion in a combustor which is a heat source of a hot-water boiler or a hot-air heater includes a memory circuit which generates an alarm signal and also a signal for stopping the operation of the apparatus and which maintains the apparatus in the shutdown state, when an abnormal condition such as abnormal heating or ignition failure is sensed. This memory circuit is protected from malfunction due to noise generated from external output units in the combustion control apparatus by a circuit which detects an abnormality signal with timing other than the timing of generation of noise from the external output units, and the output of this circuit is applied as an input to the memory circuit. The detection circuit is arranged to detect the abnormality signal while receiving clock pulses from a timer as its input, and the phase of its detection timing is selected to be out of phase with the noise generation.

Abstract: Control device for at least one sequential burner of a cooking apparatus, comprising in combination:a geared-down synchronous motor and a drum which can be driven in rotation by this motor,an electric circuit associated with this drum, comprising at least one electric contact pressing upon the surface of the drum and at least one electrically conductive track arranged on the drum in such manner as to permit operation of the burner according to heating sequences which are variable as a function of the position of the electric contact on the drum, and means for adjusting the position of the contact in relation to the conductive track in order that the duration of the heating sequences of the burner may be varied progressively and continuously.

Abstract: A timer and control circuit using a field effect transistor that is operated in three different current carrying conditions or operating modes is disclosed. The three operating modes are used to establish two successive timed intervals for a prepurge and a trial for ignition for a fuel burner.

Abstract: This invention relates to a control circuit which controls combustion in a burner acting as a heat source of a hot-water boiler or a hot-air heater. More particularly, the present invention relates to a control circuit having a sequence which includes post-discharge such that electric discharge for ignition is still continued for a predetermined period of time, even after attainment of ignition. In a combustion control apparatus, when ignition is not attained within a predetermined safty period, the igniting operation is stopped by a safty timer for timing this safety period, thereby ensuring the safety. It is necessary to reliably discontinue the igniting operatin even when this safety timer is disabled. The present invention attains this object and ensures the safety with a reduced number of timers.

Abstract: In an apparatus for successively igniting a plurality of incense sticks or other elongated combustible articles, a series of timer discs on a common shaft is rotated by an electric motor. The rim of each disc is provided with a bore for holding one end of an incense stick. The opposite end of the stick is supported beneath an igniter element. As the motor shaft rotates, the timer discs are successively rotated to move the incense sticks, one at a time, into contact with the igniter element. Following ignition, each incense stick is further rotated for exposure to the atmosphere until fully consumed. The speed of rotation of the timer discs is controlled to provide complete consumption of an incense stick during each shaft revolution.

Abstract: A circuit for safely admitting fuel to a burner, igniting the fuel, detecting the presence of flame at the burner, and preventing the escape of unburned fuel from the burner if ignition is not accomplished or the flame is interrupted. An initiation circuit operates a control signal generator during a time delay period and a valve operating circuit opens a fuel valve to admit fuel to a burner. An igniter circuit is operated in response to energization of the valve operating circuit to produce sparks for ignition of the fuel. A flame detector circuit powered by the valve operating circuit detects the presence of flame and, in response, the operation of the control signal generator is maintained and the operation of the ignition circuit is interrupted. The operation is fail-safe, the detection of flame is reliable despite power supply variations, and no power supply transformer or valve operating relay is required.

Abstract: A check circuit for checking operation of timers of a digital type combustion process control apparatus comprises flip-flops each having a preset terminal. The preset state of the flip-flops is inverted by an operation starting signal. The inversion is detected by a detector circuit the output signal of which is utilized for driving the control circuits for a combustion apparatus. The detector circuit is composed of a flip-flop circuit having input terminals applied with the operation initiating signal and the inverted output signal from the timer circuit.

Abstract: A flame responsive control circuit means has been disclosed which responds to the flame in a burner. The response is to the sudden rate of change of the resistance or impedance of a photocell upon the loss of flame. The two embodiments disclosed both utilize a rate of change sensing means to determine that a loss of flame has occurred. If a loss occurs, ignition is reinstituted immediately and the system either operates normally or locks itself out in a safety shut down.

Abstract: A safe start check circuit for a fuel burner is disclosed. Two relays are arranged to insure proper start and to protect against component failure. Delays in operating the relays, and a normally closed control relay contact serve to both prevent relay races and provide protection against a solid state switch means failure.

Abstract: A system for controlling the pilot and main burner gas valves of a gas furnace or the like, including a pilot spark ignitor and a pilot flame sensor. A main burner valve control circuit for energizing the spark ignitor until a pilot flame is sensed and then energizing the main burner valve solenoid to provide gas to the main burner. A pilot solenoid valve control circuit for controlling application of power to the ignitor circuit and the pilot and main solenoids. A safety turn on control circuit which permits operation of the pilot valve and ignitor circuit for only a limited period of time to provide a fail safe operation of the ignition system.

Abstract: Disclosed is a combustion control apparatus of digital type, in which a fault is warned of unless ignition resumes in a predetermined time after the start of igniting operation in the reignition when fuel flaming is extinguished during combustion. The predetermined time is called safety time and the combustion control apparatus can exactly obtain such a required time or period as the safety time. With such a digital type combustion control apparatus, the safety timer for establishing the safety time comprises flip-flops adapted to count reference clock pulses. In this apparatus, the circuit for generating the reference clock pulses is set and reset by the flame extinction signal to synchronize the clock pulses and the flame extinction signal so that the safety time may be free from error. This concept can be applied to determine the prepurge time.