Abstract: A one-shot thermal fuse mounted directly on the casing of a centrifugal pump to prevent overheating and concentration of ammonium nitrate. The thermal fuse is screwed into a standard pipe coupling welded to a designated location on the pump casing. The thermal fuse has an electrical contact connected in the pump control circuit. A compressed spring is prevented from urging the electrical contact into an open position by a pellet of fusible material which is designed to melt at a desired threshold temperature below the temperature at which ammonium nitrate explodes. If the heat produced by the pump melts the pellet of fusible material, the spring is released, thereby opening the electrical contact and shutting off the pump. Alternatively, the temperature-sensitive element mounted on the pump casing can be a thermocouple or a temperature switch having a bimetallic element.

Abstract: A motor control system for a fuel burner comprises a microprocessor and a voltage fluctuation compensating portion provided with a bridge circuit for rectifying the current of a power source, a portion for generating a comparison signal having a delay time corresponding to the voltage fluctuation of the rectified signal from the bridge circuit and a portion for generating a zero-crossing signal from the voltage signal of the bridge circuit, whereby a microprocessor determines whether a power voltage applied to the system is higher or lower than a normal voltage. The microprocessor generates a compensating signal programmed to equalize the fluctuation power to the reference power and a controller controls the power to be applied to a load according to the compensating signal.

Abstract: The liquid fuel burning apparatus includes a fuel tank, a burning unit for burning the fuel, an electromagnetic pump for sucking the fuel from the tank, a feeding pipe for feeding the sucked fuel to the burning unit, and a control unit for controlling the electromagnetic pump. The electromagnetic pump has a plunger which is reciprocated by a plunger solenoid to suck the fuel in the fuel tank and discharge the sucked fuel therefrom in the associative motion of a suction and a discharge valves incorporated therein. The control unit opens the valves for a predetermined time when the fuel supply is stopped. Thus, fuel remained at an end of the feeding pipe is collected from so that the unburnt gas or strange smell which would be generated when the unnecessary liquid fuel is supplied to the burning means can be restricted.

Abstract: At least two sets of point-to-flat spark electrodes are connected for high voltage excitation from a pulse source such as individual secondary windings of a common transformer. Each secondary winding has one end connected to one of the pointed electrodes, with the other end of the winding commonly grounded with the flat electrode to provide common polarity to all pointed electrodes.

Abstract: A burner and burner firing method and system for a furnace combustion chamber in which a burner, having an ignition chamber for discharging an ignited combustible mixture of primary air and fuel into the furnace combustion chamber, and a plurality of nozzle ports for directing a high velocity stream of secondary air into the furnace combustion chamber in a direction generally parallel to the direction of flow from said ignition chamber, is operated in a first mode at furnace combustion chamber temperatures up to a transitional temperature by accelerating a burning mixture of fuel and air to moderately high velocities into the furnace combustion chamber, and in a second mode at furnace combustion temperatures above said transitional temperature by introducing a relatively low velocity stream of fuel mixed with a minor amount of air needed for stoichiometric combustion and accelerating a separate stream of air to high velocities into the furnace combustion chamber for mixture with said low velocity stream downs

Abstract: A system is disclosed for monitoring the output of a gas ignition module used for controlling the heating of a cooking device, such as a deep fat fryer, in a pulsed heating mode. The system includes a controller which detects a failure in ignition and alerts the user of the cooking device of such a failure. In a preferred embodiment, an optoisolator is used to monitor the voltage applied to a gas valve. From this determination, the system logically determines when a gas lockout has occurred, and prevents successive ignition attempts, which could result in an unwanted accumulation of gas.

Abstract: Difficulties with starting reliability and/or combustion stability in hot gas generating systems are avoided in a construction including a storage vessel (36) for storing an oxidant, a fuel supply (22) and combustion chamber (26) having an out outlet (30) for hot gas. A fuel injection nozzle (28) provides fuel from the supply (22) to the combustion chamber (26) while an oxidant duct (44) connects the vessel (36) to the combustion chamber (26). A choked orifice (46) is disposed in the duct (44) just upstream of the combustion chamber (26) and a bypass duct (50) interconnects the combustion chamber outlet (30) and the oxidant duct (44) between the choke orifice (46) and the combustion chamber (26). A selectively operable valve (53) is disposed in the bypass duct (50) and a pressure regulator (44) is disposed in the oxidant duct (44) for selectively controlling the pressure of oxidant applied to the choked orifice (46).

Abstract: A heat exchanger system, a fuel control system therefor and methods of making the same are provided, the fuel control system having an electrical circuit means that comprises an ignition trial portion, a flame sensing control portion and a timer portion that comprises a counter having a plurality of outputs and a timer that clocks the output of the counter on each discharge of the timer, the timer portion also comprising a capacitor, a trial time resistor and a wait time resistor that are selectively placed in series with the capacitor by the counter when clocked to certain outputs by the timer to determine an ignition trial time period and a wait time period.

Abstract: A method for adjusting a burner during the start-up phase in a furnace operated with recirculated flue gas (3), the furnace is subjected to a pre-flushing period prior to start-up. The furnace is started with a constant fuel amount (5), the fresh air (2) aspirated from the outside at first being reduced by means of a control. In the beginning, the stoichiometric or near-stoichiometric air balance for combustion is provided by recirculation of the fresh air (4) in the furnace. Following ignition of the burner, an increase of fresh air (2) from the outside will take place as a function of the diminishing fresh air (4) from the furnace. The diminishing fresh air (4) recirculated from the furnace is replaced by also recirculated flue gases (3) in such a way that at the end of the start-up phase only a combustion air mixture consisting of fresh air (2) from the outside and recirculated flue gases (3) is used.

Abstract: The present invention is a furnace control system responsive to a circulator fan motor fault condition. Upon detection of the fault, the control determines a first time period which is required to activate the temperature limit switch of the furnace by continuous operation of the gas burner and a second time period which is required for the plenum to dissipate sufficient heat to deactivate the temperature limit switch. After determining the first and second time periods, the furnace control operates the burners for a fraction of the first time period and then allows the heat exchangers to cool for the second time period until the circulator fan motor fault is corrected or the demand for heat ceases.

Abstract: In this air-conditioner, combustion test of a refrigerant heater is conducted through a control valve on the basis of a minimum combustion command signal and a maximum combustion command signal set in advance at a plurality of stages to store values of the minimum combustion command signal and the maximum combustion command signal presenting an optimum combustion state from the above-mentioned command signals, whereby in an actual operation, control of the control valve is carried out by using stored values with respect to the minimum combustion command signal and the maximum combustion command signal.

Abstract: A process and apparatus for monitoring and ensuring safe operation of unvented kerosene heaters in indoor spaces detects the hazard of incomplete combustion and the concomitant reduced O.sub.2 and increased CO.sub.2 levels in the indoor air. CO.sub.2 level in the indoor air is monitored quickly and accurately, - regardless of the burner's flame height. This is achieved by sensing O.sub.2 level in the burner exhaust which is used as a measure for monitoring the CO.sub.2 level in the indoor air and as a control signal. During burner operation outside a predetermined flame height range, the O.sub.2 detection is used both for restoring a normal heating condition and for monitoring operation at minimum flame height and to generate a warning signal and a delayed automatic shut-down of the burner.

Abstract: A heat exchanger system, a fuel control system therefor and methods of making the same are provided, the fuel control system having an electrical circuit means that comprises an ignition trial portion, a flame sensing control portion and a timer portion that comprises a counter having a plurality of outputs and a timer that clocks the output of the counter on each discharge of the timer, the timer portion also comprising a capacitor, a trial time resistor and a wait time resistor that are selectively placed in series with the capacitor by the counter when clocked to certain outputs by the timer to determine an ignition trial time period and a wait time period.

Abstract: Provided is an atomizer-equipped combustion apparatus including an atomizing device for atomizing a fuel, a spray chamber for mixing the fuel atomized by the atomizing device with air to form a mixture, and for moving the mixture downwardly toward an opening at a distal end portion of the spray chamber, and a wind box provided so as to surround a lower portion of the spray chamber for forming a combustion space between itself and the spray chamber, the wind box being provided with a plurality of air supply holes facing a lower portion of the spray chamber. A mixture of external air and a fine spray of fuel produced by the atomizer can be ignited instantaneously by means of a comparatively simple structure, odors produced at igition and extinguishment can be greatly suppressed and a high turn-down ratio can be obtained.

Abstract: A fail-safe gas valve driver circuit controlling the gas supply line of a gas burner, which circuit in its essential circuit elements (FIG. 1) includes an appropriate switching means (S1) effectively feeding a pulsed DC wave form into the rest of the valve relay driver circuit, operatively consisting only of a capacitor (C1) in series with a gas valve relay (K1), which in turn is in parallel with a diode (D1). In operation, the valve relay coil is energized by charging the capacitor with the switch connected to a positive DC voltage source (V.sub.dc ; FIG. 1A), and then grounding the positive end of the capacitor (switch connected to ground) applying a negative voltage across the coil of the relay (FIG. 1B). When the capacitor is again connected to the positive DC voltage source by the switch, the current in the relay coil is sustained by the diode (FIG. 1C).

Abstract: A hot surface ignition system for a gas furnace or the like, control device therefor and methods of making the same are provided, the system comprising a burner, a settable thermostat, an electrically operable gas valve, a control unit, and an electrically operable hot surface igniter disposed so as to be in the path of gas issuing from the burner that is adapted to be fed the gas from a source thereof through the gas valve when the control unit has been activated by the thermostat to operate the igniter and the gas valve in a certain sequence, the control unit having a lockout unit for deactivating the system should ignition of the gas issuing from the burner not take place by the end of the certain sequence, the control unit having a resetting unit for causing the control unit to be reactivated to be adapted to repeat the certain sequence of the system when the resetting unit is activated, the control unit being adapted to select the certain sequence to have one or more attempts of the control unit to ignit

Abstract: The invention provides a combustion device such as a stove which may include a pressurized fuel mixture, such as an aerosol container containing alcohol and a propellant which may comprise a normally gaseous hydrocarbon, such as a liquified petroleum gas. The propellant and air are fed to a combustion zone as a combustion mixture, which is combusted therein in a cold start period to pre-heat the liquid fuel and vaporize it. When the liquid fuel is vaporized by the heat provided by combusting the propellant gas, combustion is continued by combusting the vaporized liquid, e.g., alcohol, fuel. The pressurized fuel composition may comprise a major proportion of alcohol together with a minor proportion of the hydrocarbon propellant starter fuel. The method therefore includes carrying out an initial, cold-start phase of combustion utilizing the propellant as fuel, and a subsequent stage of combustion utilizing the vaporized liquid fuel.

Abstract: A method and apparatus detect a faulty air switch in a heating system which has an operation cycle comprising a plurality of operating periods. The air switch senses air flow in the heating system and causes air flow limit contacts to open when the air flow is outside a predetermined limit. The air flow is outside the predetermined limit during a first operating period of the operation cycle. A series circuit comprises the air flow limit contacts, coupled in series with other limit contacts between a limit sense terminal and an energized input terminal. The other limit contacts should be closed during the first operating period of the operation cycle. The limit sense terminal is sampled during the first operating period to determine whether the limit sense terminal is energized. Based on whether the limit sense terminal is energized, the air switch is determined to be faulty or operating properly.

Abstract: A hot surface ignition system for a gas furnace or the like, control device therefor and methods of making the same are provided, the system comprising a burner, a settable thermostat, an electrically operable gas valve, a control unit, and an electrically operable hot surface igniter disposed so as to be in the path of gas issuing from the burner that is adapted to be fed the gas from a source thereof through the gas valve when the control unit has been activated by the thermostat to operate the igniter and the gas valve in a certain sequence, the control unit having a lockout unit for deactivating the system should ignition of the gas issuing from the burner not take place by the end of the certain sequence, the control unit having a resetting unit for causing the control unit to be reactivated to be adapted to repeat the certain sequence of the system when the resetting unit is activated, the control unit being adapted to select the certain sequence to have one or more attempts of the control unit to ignit

Abstract: A method and apparatus monitor fuel pressure in a heating system where a controller controls actuation of fuel valves. A fuel pressure limit signal is provided to the controller for determining if the fuel pressure crosses predetermined thresholds. In order to avoid nuisance shut-downs, the fuel pressure limit signal is ignored by the controller for a predetermined time interval after the controller has actuated a fuel valve.

Abstract: A method of carrying out a gas combustion process with recovery of the heat from the combustion gases, which comprises passing said gases during the stationary condition of the process through a recuperator in which a part of the heat released is used for heating the air required for the combustion, and then passing the gases through a reformer in which a part of the residual heat is used for converting fresh gas to be burned with steam, in which method at least during the non-stationary conditions of the process a cooling medium is supplied to the combustion gases before introducing them into the reforming reactor.

Abstract: A microprocessor control determines, in the course of initiating a heating cycle, whether the blower is operating in the continuous mode, and if it is, the control prompts the blower to be turned off prior to the ignitor being turned on. In this way, the blower and ignitor are never on at the same time and the instantaneous total current draw is limited to thereby reduce the occurrence of burned out fuses or circuit breaker trips.

Abstract: An improved steady state fuel burner assembly and method of operation for a space heater wherein fuel and combustion air are initially ignited within a burner assembly with the resulting higher pressure in the burner assembly causing throttling of combustion air into the burner assembly until a preselected lower pressure is reached compatible with steady state combustion through exhaustion of initially combusted gases.

Abstract: Provision is made for sensing when the gas valve relay contacts are welded, or stuck, in the closed position and for responsively turning off the inducer motor when that occurs. This in turn causes the pressure switch to open to thereby cut off the power to the gas valve and cause it to move to the closed position.

Abstract: A method for starting up a partial combustion process, using a burner, wherein finely divided carbon-containing fuel is supplied to a reactor or gasifier and an oxygen-containing gas is supplied separately from the said fuel to the reactor or gasifier and is mixed with the said fuel adjacent the outlet of the burner in the reactor or gasifier. During a predetermined period a low rank particulate carbon-containing fuel is supplied to the reactor prior to the start of the partial combustion process, said low rank fuel spontaneously reacting with oxygen when brought into contact with the said oxygen-containing gas and subsequently switching the burner to a less reactive finedly divided carbon-containing fuel.

Abstract: Improved combustion of liquid fuel is achieved with a porous fiber burner by forming a mixture of the vaporized fuel and all of the desired combustion air sufficiently heated to prevent condensation of the vaporized fuel, and introducing the heated mixture into the porous fiber burner to effect flameless combustion on the outer surface of the burner. The resulting surface combustion produces a high proportions of radiant heat and increased thermal efficiency while suppressing the formation of nitrogen oxides and other pollutants in the flue gas. Periodically, fuel gas may be supplied to the same porous fiber burner.

Abstract: A gas conducting tube (12) with a flat end (14) cut off at an angle is pivotal above the burner head 10 for lighting the flame of an atomic absorption spectrometer. Gas emerging from the burner is passed through the tube from the first end 14 to a second end 16 where a glow filament 24 is arranged. The diverted gas is lit and flashes back to the burner, whereby the flame thereof is lit. After the flame has been lit, the tube 12 is rotated out of the area of the burner head 10.

Abstract: A liquid-fueled thermoelectric field burner operable in two modes, a start-up mode and a steady-state mode. A rechargeable battery backed up by a manually operated generator permits cold start-up of a preheat burner followed by operation of a main burner which provides heat to thermoelectric converters which operate to provide necessary power for steady-state operation. Cold start-up is facilitated by atomizing the liquid fuel for combustion in the preheat burner, and steady-state blue flame operation is enhanced by mixing vaporized fuel and preheated air for combustion in a main burner. The thermoelectric converters are cooled by air from a cooling blower.

Abstract: A hot surface ignition system for a gas furnace and method of making the same are provided, the system comprising a high voltage circuit for being connected to a source of high voltage AC current, the high voltage circuit having a hot surface igniter therein and disposed in the path of gas issuing from a burner that is adapted to be fed gas from a source thereof through an electrically operated gas valve, a low voltage circuit for being connected to a source of low voltage AC current, the low voltage circuit having the gas valve therein and having a thermostatic switch therein controlling the energization of the low voltage circuit with the low voltage AC current, a first relay unit having contacts in the high voltage circuit and controlling the energizaiton of the igniter with the high voltage AC current, and another relay unit having contacts in the low voltage circuit and controlling the energization of the gas valve, the other relay unit comprising two separate relays respectively having contacts that are

Abstract: A pulse-fired burner is operated by modulating a fuel supply rate between a pilot level and a main level to provide a flame the level of which modulates respectively between a pilot level during a non-firing phase and a main flame level during a firing phase. Air supplied at a pilot rate is premixed with the fuel before ignition, the pilot air level being sufficient to support combustion of the fuel at the pilot rate but not at the main rate. The supply of fuel is terminated if no flame is sensed.

Abstract: A low intensity infrared radiant heating system comprising an exhaust effluent temperature sensor for disabling burner operations to keep thermal operating efficiences within preselected limits. A minimum burner run timer is used to avoid corrosive condensate accumulation in the primary emitter length. Multiple burner systems utilizing a microprocessor control system is disclosed.

Abstract: A method for igniting a multiburner furnace safely and reliably without need for an additional furnace purge if not all burners ignite initially, comprising attempting reignition at defined low firing rates and supplying fuel and oxidant to unignited burners at a high firing rate when a specified furnace temperature is reached.

Abstract: The flame in a flame atomic absorption spectrophotometer is shut down while using nitrous oxide as the oxidant, without shifting to a different oxidant such as air, by flooding the burner with a substantial excess of nitrous oxide to blow out the flame.

Abstract: A combustible mixture composed of a flowing fuel and gaseous oxygen is ignited by exposing one or both of the constituents of the mixture to a region of corona discharge in order to generate molecular radicals which subsequently combine with radicals of the other constituent to initiate combustion. The apparatus includes at least two electrodes (14 & 16) having a voltage potential impressed thereacross to generate a region of intense electric field and means to maintain the resulting voltage-current characteristic relationship within a corona discharge region of operation (42).

Abstract: To avoid venting of a deburring chamber and associated equipment after charge of the chamber with an explosive mixture if a spark plug (3a) has failed to ignite the mixture, a glow ignition block (4) is located in the path of gas communication between a mixing block (3) in which the spark plug is retained, and a glow plug (8) is located to have its glow portion exposed to the combustible gas mixture, preferably in a bypass (9) to a main gas path. A thermal element (12) monitors whether, upon application of an ignition pulse to the spark plug (3a), ignition has occurred by sensing a sharp temperature pulse; upon failure to sense such a temperature pulse, the glow plug is energized for ignition of the combustible mixture thereby. The spark plug may be of the vehicular internal combustion engine type; and the glow plug may, for example, be similar to "pre-glow" plugs used in vehicular-type Diesel engines.

Abstract: Method and means are disclosed for stimulating combustion especially of lean mixtures in internal combustion engines. For example, an ultraviolet lamp mounted in the combustion chamber of an engine directs radiation of wavelength exceeding 190 nm on the advancing flame front. The radiation largely passes through the cool unburned mixture and is absorbed in disassociating oxygen molecules in the flame front thereby stimulating combustion of the flame and allowing the burning of exceptionally lean air-fuel mixtures. Numerous features and alternative embodiments are disclosed.

Abstract: A system is provided for igniting and monitoring a fuel burning heat source which comprises a thermoelectric safety burner valve, a thermocouple to be heated by a pilot burner, a fuel source feeding fuel to a pilot feed valve and to a main burner feed valve, which in turn are connected to the pilot burner and respectively the main burner. An electric supply source is provided for energizing either an ignition voltage generator or a thermostat simulator. The igniting and monitoring system can be operated electrically or otherwise manually regardless of the state of the electric supply source. A manually operable pilot fuel valve is connected in parallel to the electrically actuated pilot fuel valve and is connected with a switch for disconnecting the electric supply voltage. Thus the heat source can be operated manually in cases where the electrical supply source is not available without impairing the generation of heat.

Abstract: A draft control system for furnaces comprises an auxiliary channel in communication both with ambient air and the flue of the furnace, a main draft control means for regulating the entrance of ambient, auxiliary draft air into the flue, and auxiliary draft control means mounted in the auxiliary channel for dampening the effect of extreme changes in external conditions on the main draft control means. Thus, uniform draft and efficient combustion is maintained in the furnace under a wide variety of conditions. The main draft control means comprises counter-balanced draft control plates which are initially set in an open position so that they can either open or close in order to efficiently regulate the draft in the flue. The auxiliary draft control means comprises, in one embodiment, an isolation damper plate rotationally mounted in the auxiliary channel, or, in a second embodiment, a set of louvred panels.

Abstract: An ignition system for post-mixed gas burner which achieves reliable ignition without requiring an expensive spark source protection device, or a means to promote fuel-oxidant mixing, or a large amount of electricity, or a separate pilot light.

Abstract: The present invention relates to a self-checking safety switch control circuit for a power combustion system. The circuit comprises a safety switch, a combustion blower relay, a thermal pilot switch, and a fuel supply system. The safety switch operates to detect flow through the combustion system. The safety switch either operates the pilot switch directly or operates the fuel supply system directly to shut down the system if no flow through the combustion system is detected. The circuit has a self-checking feature because combustion cannot be initiated in a subsequent cycle of the system if the safety switch remains in the proven condition from the previous combustion cycle.

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: A method for starting up a partial oxidation gas generator without a separate preheat burner is described. The burner used includes central and annular bunches of parallel tubes that extend through central and annular passages formed by concentric conduits.

Abstract: An assembly and method for heating a fluidized bed combustion chamber to ignition temperature, wherein a heated gas flows through heat exchange tubes extending into the fluidized bed to provide sufficient heat for raising the temperature of the bed material and the combustion air to allow for ignition of the combustion fuel. A conduit system is provided for selectively recycling combustion air through the combustion chamber during the ignition process.

Abstract: The invention concerns a method for the operation of gasification plants for pulverized fuels, wherein the pulverized fuel is reacted in a flame reaction with a gasifying agent containing free oxygen, into a combustible gas containing CO and H.sub.2. The task consists in precluding upon malfunctions in the supply of fuel, an oxygen discharge into the cooling and treatment plants, taking into consideration delays in the emergency shut-off systems and the controls for the oxygen supply.As per invention, a well-flowing additional fuel is stored in a reservoir at a pressure higher than the operating pressure of the gasification reactor. Upon malfunctions in the fuel supply, the additionally stored fuel will be transferred, within a short time, into the reaction chamber of the gasification plant. As additional well-flowing fuel combustible gas, liquid fuel or a pulverized solid fuel, also well-flowing, can be used.

Abstract: Apparatus for igniting a main gas mixture to be burnt in a combustion chamber includes conduit systems for separately feeding an oxygen-bearing gas and a combustible gas into an ignition region. At least a part of at least one of the conduit systems is formed as an electrical heating resistance thereby to raise the temperature of the gas component flowing therein so that when the components are mixed in the ignition region, ignition of the ignition gas mixture will occur, thereby igniting the main gas mixture. The apparatus also includes means for detecting the temperature of the heated gas component or components flowing through the conduit systems, and/or the temperature of the gas mixture ignited in the ignition region.

Abstract: A package heat exchange system is disclosed having a burner positioned in the central plenum of a substantially cylindrical heat exchanger. A fuel-air mixture is supplied through a blower supplied with fuel from a pressure regulator which requires a somewhat less than atmospheric pressure at the blower inlet to draw gaseous fuel through the pressure regulator. A solenoid-operated, positive pressure valve in the main gasline provides the heat exchanger with an enriched gas mixture on ignition. The enrichment valve automatically closes after 30 seconds of operation. Air for combustion is drawn through a series of orifice plates positioned between the regulator and the blower. The fuel-to-air ratio may be altered by changing the size and/or number of the holes in one of the orifice plates. Further, one of the orifice plates may be deformable so as to form a seal, and to supply a predetermined quantity of air to the burner for combustion.

Abstract: A flame cutting machine includes an ignition system for igniting the fuel gas which is connected by a transverse bore to a longitudinal bore parallel to the blend canal of the machine.

Abstract: A method and apparatus for hydrocarbon flame ignition and detection is disclosed utilizing a pair of flame-detecting electrodes positioned at the flame site in contact with the flame and in a spaced-apart relationship to accommodate, in the gap therebetween, essentially the flame's reaction zone. At least one of the electrodes may additionally serve as the ignition element and is, accordingly, sufficiently electrically resistive so as to undergo self-heating in response to current flow therethrough.A second aspect of the invention relates to the direct application of AC line voltage across the resistive electrode during the ignition phase and across the electrode gap during the detection phase.A third aspect of the invention concerns the thermal-heating of both electrodes by the flame to reduce both the ignition time and the "wall quenching" effect of the otherwise cool electrode surface on the high-conductivity plasma in the reaction zone.

Abstract: When a call for heat is established, a flame relay is actuated for a predetermined time by means of a cycling timer. Upon this initial actuation, the flame relay inhibits a checking relay and initializes a trial-for-ignition (or simply "ignition") timer. After the cycling timer times out and the flame relay has been completely cycled, which established operativeness of the flame relay and flame sensing circuitry, the checking relay is enabled and actuated for the ignition period. The checking relay then actuates the pilot valve and a spark generator to start a pilot flame. If a flame is sensed, before the ignition timer times out, the flame relay actuates the main valve and establishes a holding current for the ignition timer so that the checking relay continues to be energized. If a flame is not sensed during the trial period, the ignition timer disables the checking relay, thereby de-energizing the pilot valve before the main valve is opened.

Abstract: A fail-safe apparatus and method for controlling the sequence of gas feed and ignition, such as by an incandescent igniter, in a gas-fired appliance, such as a thermostatically controlled timer activated clothes dryer. When the appliance is activated by the timer, the control apparatus energizes the igniter and opens a gas valve only after the igniter is energized for a period that is sufficient to heat the igniter to the temperature required to kindle the gas. If the gas is ignited, the control apparatus holds the gas valve open so that the gas continues to burn. If, however, the gas is not ignited, the control apparatus inhibits any further attempt at gas feed and ignition. If a temporary electrical power outage occurs, if the gas supply is interrupted, if the thermostat cycles on and off, or, in the case of a clothes dryer, if a loading/unloading door is opened and then shut again, the control apparatus repeats the gas feed and ignition sequence in an attempt to rekindle the gas.