Abstract: One embodiment provides an apparatus for displaying an image comprising: a first optical substrate comprising at least one waveguide layer configured to propagate light in a first direction, wherein the at least one waveguide layer of the first optical substrate comprises at least one grating lamina configured to extract the light from the first substrate along the first direction; and a second optical substrate comprising at least one waveguide layer configured to propagate the light in a second direction, wherein the at least one waveguide layer of the second optical substrate comprises at least one grating lumina configured to extract light from the second substrate along the second direction, wherein the at least one grating lamina of at least one of the first and second optical substrates comprises an SBG in a passive mode.

Abstract: A safety shut-off system and method for eliminating power to a load in the event of smoke detection. The system may comprise a device located at the appliance for detecting a signal from a smoke detector, and cutting power to the appliance only when the appliance is in use. The device may be synchronized with any standard smoke alarm signal to reduce the number of false positive shut-offs. The system may also comprise a smoke alarm hard-wired to a circuit breaker, for shutting off power to all appliances on a particular breaker upon receipt of a signal from the smoke alarm, and only when the appliances on the breaker are in use. The system may also have the ability to shut off one breaker, multiple breakers, or all breakers at different time increments to actively prevent and reduce the damages caused by fires.

Abstract: A flame-emitting apparatus is provided, whereby a burner has an inlet connected to a fuel source. Fuel burned by the burner provides a flame extending from an outlet of the burner. A flame ignition system detects the presence of the flame during operation of the apparatus and controls supply of fuel to the burner in response to flame detection.

Abstract: Systems and methods for detecting an instability associated with at least one burner are disclosed. A detector measures a signal associated with a characteristic of the at least one burner. The signal is converted to a time-varying signal spectrum using at least one processor. An instability is detected based at least in part on the time-varying signal spectrum. The instability can be detected based on an instability indicator calculated based at least in part on the time-varying signal spectrum. A threshold can be associated with the instability indicator such that an instability is detected when the instability indicator is greater than the threshold.

Abstract: A gas safety device is provided. An electronic valve connected to a thermocouple is closed to cut off the gas supply when the temperature of radiant heat directly emitted from a surface of a vessel exceeds a preset temperature level while the vessel is heated through the spark ignition of a burner, thereby preventing risks of overheating and thus fire caused due to a user's carelessness when the user cooks the food.

Abstract: A control system for a fuel-fired appliance and methods of operating are disclosed. When a failed ignition of a burner is detected, the control system is configured to enter a soft lockout state if the voltage level of a burner of the fuel-fired appliance is low during the failed ignition and a hard lockout state if the voltage level of the burner is not low during the failed ignition. In some cases, if a period of time has elapsed and/or the voltage level of the burner has increased after the control system enters the soft lockout state, the control system may be configured to initiate one or more subsequent ignition trials. In some cases, if the one or more subsequent ignition trials fail, the control system may be configured to then enter the hard lockout state.

Abstract: A system for predicting fouling and corrosion of a combustion system in an industrial process includes a pipe, a restrictive element, and a fouling and corrosion detector. The pipe contains a fuel. The restrictive element is coupled to the pipe and the fuel passes through the restrictive element. The fouling and corrosion detector is coupled to the pipe and is adapted to detect a characteristic signature of the restrictive element and to generate an alarm if a change in the detected signature exceeds a predetermined limit relative to a baseline signature.

Abstract: A fuel-fired appliance is shut down when a predicted steady state combustion chamber temperature is below a known threshold. The predicted steady state temperature is based on combustion chamber temperatures during heat up of the burner and appliance.

Abstract: In certain embodiments, an apparatus can comprise a dual fuel pilot assembly. The pilot assembly can comprise a first fuel dispenser, a second fuel dispenser, an igniter and at least one of a thermocouple, and a thermopile. The pilot assembly can be configured to direct heat from combustion of one of either a first fuel or a second fuel to the at least one of the thermocouple and the thermopile.

Abstract: A signal generation system for flame ignition and sensing. The ignition signal generation is adaptive for improving flame ignition while eliminating excess energy usage. High voltage signals for flame sensing may also be provided. If more energy or speed is needed for ignition signal generation, then the flame sensing signal generation portion may be disabled to increase the amount of available energy. Adaptation for ignition signal generation may be guided by the results of flame sensing. The flame sensing voltage may be regulated based on the flame current strength. The flame current may be controlled within an optimum range to reduce rod contamination rate and yet provide reliable flame sensing when the rod contamination built up. The adaptation may be algorithmic-based with the facilitation of a microcontroller. The system may provide the high voltage signals from a low voltage power supply, such as that of 24 VAC.

Abstract: A dual fuel vent free gas heater having at least one gas burner with a plurality of gas outlet ports. The gas outlet ports are in flow communication with at least one pilot flame burner. At least one fuel injector feeds fuel to the burner providing for introduction of more than one fuel to the burner. Optionally, an oxygen detection system, manual control valve, linkage, and/or shut off control system may be incorporated into the dual fuel vent free heater.

Abstract: A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

Abstract: The aim of the invention is to create a gas regulating fitting which, once a gas stove has been successfully started up, can switch the pilot burner into the off position when the main burner is in the off position, in order to maintain the power consumption of the gas stove as low as possible. The aim of the invention is also to provide the gas regulating fitting with as simple a structure as possible. To this end, the gas regulating fitting comprises a sensor (34) by which means the operating state of the main burner (33) can be detected. The sensor (34) is connected to a thermoelectric safety pilot valve (17) in such a way that, when the operating state of the main burner (33) is switched from the on position into the off position by a signal emitted from the sensor (34), the thermoelectric safety pilot valve (17) assumes the closed position thereof. The gas regulating fitting can be used to ignite and to regulate a gas flow flowing to a burner.

Abstract: A control for controlling the operation of a fuel-fired heating appliance is provided that include a sensor capable of sensing the presence of carbon monoxide gas and providing an output indicative of the level of carbon monoxide gas. The control further includes a microprocessor that periodically reads the CO sensor output and stores at least one sensor output value in a memory, wherein the microprocessor responsively discontinues the operation of the appliance when the microprocessor detects a sensor output that has increased by more than a predetermined amount over at least one previously stored sensor output value. In one embodiment, the control is preferably configured to periodically read the sensor output value, and responsive discontinue operation of an appliance upon sensing a predetermined increase of at least a 50 percent increase over the previously monitored sensor output value over a period of about 15 to 90 minutes.

Abstract: A furnace system responsive to a thermostat includes a pollutant sensor for sensing a pollutant concentration in the furnace system. The pollutant sensor is configured to open when the pollutant concentration reaches a pollutant threshold and close when the pollutant concentration falls below the pollutant threshold. When the thermostat is calling for heat, a furnace controller monitors the pollutant sensor and disables the furnace system for a lockout period if a lockout criterion related to the pollutant sensor is met.

Abstract: A control for controlling the operation of a fuel-fired heating appliance is provided that include a sensor capable of sensing the presence of carbon monoxide gas and providing an output indicative of the level of carbon monoxide gas. The control further includes a microprocessor that periodically reads the CO sensor output and stores at least one sensor output value in a memory, wherein the microprocessor responsively discontinues the operation of the appliance when the microprocessor detects a sensor output that has increased by more than a predetermined amount over at least one previously stored sensor output value. In one embodiment, the control is preferably configured to periodically read the sensor output value, and responsive discontinue operation of an appliance upon sensing a predetermined increase of at least a 50 percent increase over the previously monitored sensor output value over a period of about 15 to 90 minutes.

Abstract: A device for igniting combustible means, especially solid combustibles such as wood, charcoal, and similar. The device includes a pressurized receptacle that is filled with a combustible medium, a spring-loaded actuating valve which selectively opens and closes a discharge port of the receptacle, preferably by applying pressure with a fingertip, and a top part that is joined to the discharge port and has a tubular extension having an adequate length.

Abstract: A gas appliance includes a pilot burner, one or more main burners, a solenoid valve coupled to the pilot burner and the main burners for controlling the pilot burner and the main burners, and a control circuit coupled to the solenoid valve for controlling the solenoid valve to operate the pilot burner or the main burner remotely. An igniting device may be coupled to the control circuit for being operated by the control circuit to selectively ignite the pilot burner. One or more batteries may be coupled to the control circuit for energizing the control circuit, and a thermo-couple may be coupled to the control circuit for selectively energizing the control circuit when the battery is out of electricity.

Abstract: A control unit for controlling operation of a fuel-fired burner includes a housing having an air inlet which is open to an interior chamber of the housing. An air pump is positioned in the interior chamber of the housing and has an air inlet which is open to the interior chamber of the housing. The air pump generates reduced air pressure in the interior chamber which draws air into the housing and into the pump's inlet. This flow of air cools an electronic controller along with other components position in the housing. The air pump may be operated to draw air from the interior chamber of the housing and supplies the air to a combustion chamber of the fuel-fired burner to facilitate operation of the burner. An associated method of advancing air to a fuel-fired burner is also disclosed.

Abstract: A method of operating a fuel-fired burner of an emission abatement assembly includes supplying a reduced amount of fuel to the fuel-fired burner in response to detection of a burner shutdown request. Such a reduced fuel supply continues for a predetermined time period after which fuel is no longer supplied to the burner. The supply of both combustion air and atomization air, along with spark generation, continues for a period of time after the fuel is shutoff. An emission abatement assembly is also disclosed.

Abstract: The apparatus (1,1?) for the detection of gas combustion in an domestic gas heater or a water heater is designed as an independent installation unit mounted on a shared support bracket (8,8?), provided with a thermoelectric generator assembly (4–6, 20–26) for supplying a safety valve (16) and a main gas valve (17) of the gas heater, generating two respective lower (Vb) and higher (Vd) voltages therefor. The thermoelectric assembly (4–6,20–26) heated by a pilot flame (3) is built up by means of one or two flat Peltier type p-n junction cells (4, 20–21), which are connected to a heat transmission element (5,25) licked by the pilot flame (3) and to a shared heat sink (6,22).

Abstract: A gas-fired water heater is provided with a combustion shutoff system which precludes further combustion within the water heater's combustion chamber in response to a combustion temperature therein reaching a predetermined level correlated to and indicative of a predetermined, undesirably high concentration of carbon monoxide present in the combustion chamber. In various illustrated embodiments thereof, the combustion shutoff system is operative to terminate further combustion air inflow to the combustion chamber, or terminate further fuel flow to the burner portion of the water heater.

Abstract: A gas-fired water heater is provided with a combustion shutoff system which precludes further combustion within the water heater's combustion chamber in response to a combustion temperature therein reaching a predetermined level correlated to and indicative of a predetermined, undesirably high concentration of carbon monoxide present in the combustion chamber. In various illustrated embodiments thereof, the combustion shutoff system is operative to terminate further combustion air inflow to the combustion chamber, or terminate further fuel flow to the burner portion of the water heater.

Abstract: A combustion type waste gas treatment system is capable of oxidatively decomposing a hazardous combustible waste gas while heating efficiently with a structure which allows the waste gas to mix with an auxiliary burning gas efficiently without the occurrence of backfire in a waste gas inlet pipe. The combustion type waste gas treatment system has a burner part and a combustion chamber. Combustion flames are formed to extend from the burner part toward the combustion chamber, and a combustible waste gas is introduced into the combustion flames from waste gas inlet pipes thereby oxidatively decomposing the waste gas. A flow velocity accelerating device makes the flow velocity of the combustible waste gas flowing through the waste gas inlet pipe higher than the burning velocity of the combustible waste gas.

Abstract: A gas-fired water heater is provided with a combustion shutoff system which precludes further combustion within the water heater's combustion chamber in response to a combustion temperature therein reaching a predetermined level correlated to and indicative of a predetermined, undesirably high concentration of carbon monoxide present in the combustion chamber. In various illustrated embodiments thereof, the combustion shutoff system is operative to terminate further combustion air inflow to the combustion chamber, or terminate further fuel flow to the burner portion of the water heater.

Abstract: A gas-fired water heater has a combustion chamber with a bottom wall defined by a perforated flame arrestor plate forming a portion of a flow path through which combustion air may be supplied to a burner structure within the combustion chamber. During firing of the water heater a combustion air shutoff system having a heat-frangible temperature sensing structure disposed within the combustion chamber senses an undesirable temperature increase in the combustion chamber, caused by for example a partial blockage of the flow path, and responsively terminates further air flow into the combustion chamber, thereby shutting down the burner, prior to the creation in the combustion chamber of a predetermined elevated concentration of carbon monoxide.

Abstract: A method for a security control of a burner, provided with a body comprising a diffuser in which apertures for the flow of a mixture of air and fuel are made, comprises detecting a temperature representative of the temperature of said diffuser in at least one zone of the diffuser, generating a signal having an intensity depending on said representative temperature.

Abstract: A fire display apparatus comprises a structural base plate supported in a horizontal attitude within a clay, or other fire resistant bowl. The base plate supports an annular burner tube on a outer, upwardly facing surface, the burner tube providing outwardly directed plural burner apertures adapted for directing flames in an outward direction. The base plate also supports a burner fence positioned in spaced-apart relationship with the burner apertures and adapted for directing the flames upwardly away from the outer face of the base plate. Burner gas is conducted to the space between the bowl interior and the underside of the base plate. Here, gas valves and a flame sensor provide automated flame monitoring and control. A system control unit is heat insulated using standoffs, an insulating mat and a heat cage.

Abstract: A fuel-fired power vented heating appliance, representatively a water heater, has, in its draft structure, a single thermal or other type of cutoff switch which serves the dual function of preventing (1) the creation of an unacceptably high level of carbon monoxide in the combustion chamber of the appliance, and (2) thermal damage to a PVC vent pipe portion of the draft structure. When triggered, the cutoff switch operates to terminate further firing of the appliance. In one illustrative embodiment of the appliance, this is achieved by preventing further combustion air flow to the appliance. In another illustrative embodiment of the appliance, it is achieved by terminating further fuel flow thereto.

Abstract: An improved pilot guard for controlling the flow of gaseous fuel to both a pilot burner and a main burner, the pilot valve comprising a housing having an inlet port, a pilot port and a main burner port; a bore extending through the housing between the pilot port and main burner port; a stop shuttle normally biased to a seated position in which it blocks communication between the inlet port and the bore; a reset shuttle positioned in the bore for lifting the stop shuttle from its seated position, the reset shuttle supporting a sealing member for sealing the inlet port from the main burner port but permitting communication between the inlet port and the pilot port when the reset shuttle lifts the stop shuttle from its seated position; a thermocouple capable of generating a current from the heat of the pilot burner; an electromagnet connected to the thermocouple and capable, when fully energized, of holding the stop shuttle from moving to its seated position; wherein the reset shuttle is movable by the force of

Abstract: A heating apparatus for a motor vehicle including a heat exchanger having a wall for separating a heated exhaust gas from a heat exchange medium, a conveyor mechanism for conveying the heat exchange medium along the wall, and a protective mechanism for protecting the heater against overheating. The protective mechanism determines the mass flow of the heat exchange medium delivered by the conveyor mechanism when the heater is actuated so that the danger of overheating the heater is reliably detected when the delivery of the heat exchange medium is dammed.

Abstract: A fire display apparatus comprises a structural base plate supported in a horizontal attitude within a clay, or other fire resistant bowl. The base plate supports an annular burner tube on a outer, upwardly facing surface, the burner tube providing outwardly directed plural burner apertures adapted for directing flames in a peripheral, horizontal, outward direction. The base plate also supports a burner fence positioned in spaced-apart relationship with the burner apertures and adapted for directing the flames in an upward direction away from the outer face of the base plate. A rim fence ring is positioned outward of the burner fence and is adapted for reflecting heat inwardly. Burner gas is supplied to the space between the bowl interior and the underside of the base plate. Here, gas valves and a flame sensor provide automated flame monitoring and control.

Abstract: A fire display apparatus comprises a structural base plate supported in a horizontal attitude within a clay, or other fire resistant bowl. The base plate supports an annular burner tube on a outer, upwardly facing surface, the burner tube providing outwardly directed plural burner apertures adapted for directing flames in an outward direction. The base plate also supports a burner fence positioned in spaced-apart relationship with the burner apertures and adapted for directing the flames upwardly away from the outer face of the base plate. Burner gas is conducted to the space between the bowl interior and the underside of the base plate. Here, gas valves and a flame sensor provide automated flame monitoring and control. A system control unit is heat insulated using standoffs, an insulating mat and a heat cage.

Abstract: A main burner 22, a pilot burner 25, and a lead-in pipe 29 supplying combustion exhaust to the pilot burner 25 are arranged in a combustion chamber R2. A flame arrester 27 with small holes 27a is provided at a bottom plate 13. Furthermore, a primary thermocouple 26 detecting the flame state of the pilot burner 25 and a secondary thermocouple 28 detecting the temperature in the combustion chamber R2 are connected in series but with opposite polarities. When the flame arrester 27 clogs up with fine particles, the pilot burner 25, which sucks in combustion exhaust, performs abnormal combustion before the main burner 22, which is detected by the primary thermocouple 26 and the secondary thermocouple 28, whereupon the combustion with the main burner 22 is stopped. Thus, incomplete combustion due to blocking of the air supply path can be prevented.

Abstract: A smoke density monitor for mounting on a ship smokestack. The smoke density monitor provides a transmitter head and a receiver head mounted to a smokestack. The transmitter head and receiver head are optically connected with a density monitor by means of fiber-optic lines. The density monitor is electrically connected to an alarm monitor, which at pre-set smokestack smoke densities activates an alarm and/or shuts down the ship's burner(s). An optional recorder may be connected to the alarm monitor to preserve a record of smoke density. Each transmitter and recorder head has an optical head slidably attached to a head housing for ease of servicing and maintenance. Each head housing incorporates an exit chamber, a trap chamber and a head chamber. The head chamber houses an optical head lens. The trap chamber provides the capability of trapping particulates to prevent their adhesion to the optical head lens.

Abstract: A method for a security control of a burner, provided with a body (1) comprising a diffuser (2; 8) in which apertures (3) for the flow of a mixture of air and fuel are made, comprises detecting a temperature representative of the temperature of said diffuser in at least one zone of the diffuser, generating a signal having an intensity depending on said representative temperature.

Abstract: A safety system for a gas burning device, such as a gas range having a plurality of burner assemblies. The safety system generally comprises a gas supply valve, a gas flow sensor, a gas leak warning circuit, a no-flame warning circuit, a gas supply valve controller for receiving warning signals from the warning circuits and for closing said gas supply valve in response thereto and a fan controller for activating the fan. Other warning circuits include a timer warning circuit and a smoke detection warning circuit. A display panel shows which warning circuit has issued a warning signal. A microprocessor may perform many system functions.

Abstract: An apparatus and method for operating a pilot burner apparatus and a main burner apparatus of a gas-fired appliance. The pilot burner apparatus draws combustion air from a first environment. The main combustion apparatus draws air from a second environment. In a shutdown condition, such as when a flammable vapor source is accidentally exposed to the second environment, the pilot burner apparatus draws air containing an undesired flammable vapor which eliminates the pilot flame, triggering a gas valve to close and shut down the fuel gas supply to the main burner apparatus and the pilot burner apparatus.

Abstract: A dual mode pilot burner having a control flame mode of operation and a pilot flame mode of operation, which dual mode pilot burner is suitable for controlling the fuel/air ratio of a main burner when operating in the control flame mode of operation. The dual mode pilot burner includes a burner body having a control flame holder and a pilot flame holder disposed downstream of the control flame holder, a mixing chamber having a fuel gas inlet, an oxidant inlet, and a mixed gas outlet, which mixed gas outlet is in fluid communication with the control flame holder and a fuel gas control valve for controlling a fuel gas flow rate through the fuel gas inlet into the mixing chamber.

Abstract: Apparatus provides an air/fuel mixture to a fully premixed burner and comprises means for providing fuel at a variable flow rate to the burner, means for supplying air at a variable flow rate to the fuel to form the mixture, means for sensing aeration of the fuel combustion products and control means for controlling the fuel flow rate in dependence upon a heat output demand and the air flow rate in dependence upon both the fuel flow rate and the sensed aeration in such a way that the air flow rate is sufficient to maintain the aeration at a predetermined value, the controller, in use, maintaining the fuel flow rate at one of a number of predetermined values and the air flow rate at a corresponding one of a number of differing predetermined values, each set of predetermined values being characterized by a constant value of the ratio between successive values.

Abstract: Method and apparatus are disclosed for checking the responsiveness of a circuit which senses the presence of a flame produced by a burner within a furnace. A programmed processor associated with the circuit measures the time the circuit takes to indicate the presence of a flame. A warning is generated when the measured time exceeds a predetermined allowable time. The allowable time is determined by taking into account the decreased responsiveness of an electrode that indicates the presence of the burner flame.

Abstract: A gas radiation burner has a burner plate, and a safety element providing an ignition safety for non-burnt discharging gas for igniting gas or interrupting a gas supply. The safety element is formed as a temperature measuring resistance which contacts the burner plate via electrical conductors and is composed of a material of the burner plate.

Abstract: A gas-fired, simulated log fireplace insert incorporating an automatic flue damper for controlling the operational state of a chimney vent (open/closed) in response to gas combustion, an externally mounted carbon monoxide detector for terminating or inhibiting gas combustion in response to an unsafe level of detected carbon monoxide and a temperature actuated switch, disposed within the firebox area of the fireplace proximate the flue, for terminating gas combustion in response to excessive fireplace temperatures caused by a malfunctioning damper.

Abstract: A control system controls a combustion burner. The system has an ignition electrode to create a flame in a burner, and a first temperature sensor to sense the temperature of the flame. A control terminates the operation of the ignition electrode when a predetermined temperature is sensed by the temperature sensor.

Abstract: A pilot burner safety device of a gas combustion apparatus for shutting down a gas supply valve automatically at poor oxygen condition, includes an air intaking air means for intaking into a gas supplying passage, a heat detecting means mounted adjacent to the flame nozzle and an intaking control means mounted adjacent to the flame nozzle for controlling an air volume through the air intaking means by detecting flame temperature at the flame nozzle, and an air control means including a shape memory alloy which closes the halves of the air intaking means as a first step and opens the whole of the air intaking means at a heated condition, thereby avoiding nonignition phenomena at the initial ignition, and achieving a firing in one ignition operation.

Abstract: An apparatus for extinguishing undesired flames in liquid fuel-burning heaters having a wick partially disposed in a fuel supply reservoir in fluid communication with a fuel tank said apparatus comprising fuel flow cut-off means for interrupting said fluid communication in response to sensing excessive heat and wick withdrawal means for retracting said wick entirely into said wick fuel supply reservoir in response to sensing of excessive heat.

Abstract: A cooking unit has a ceramic cooking surface, a gas burner underneath the surface, a gas supply including a solenoid valve for feeding a combustible gas to the burner, and an electric igniter juxtaposed with the burner and electrically energizable to ignite the combustible gas issuing from the burner. An electricity supply is connected to the igniter and to the gas supply for electrically energizing the igniter whenever the valve is open and supplying gas to the burner. In addition an electronic controller connected to the valve and to the electric supply monitors current consumption of the igniter and closes the valve when the current consumption of the igniter indicates same is malfunctioning. The controller includes a digital circuit that is also typically operated by the user of the cooker to turn the burners on and off and control their temperatures and an analog circuit connected parallel to each other. At least one of these circuits controls opening and closing of the valve.

Abstract: A flame failure device for a gas-fired appliance has a heat sensitive device (24') in the form of fine bore tube (25). The tube is connected to one chamber (10) of a pressure sensitive gas flow control valve assembly. The chamber is pressurized and the rate of flow from the chamber is controlled by flow through the fine bore tube (25) the application of heat to which reduces the rate of flow through the fine bore tube (25) while the withdrawal of heat restores the rate of flow. Heat is provided by a gas burner of the appliance. The fine bore tube may have a non-circular cross-section and be formed by deforming part at least of a length of tubing (FIGS. 4A and 5B).

Abstract: The feature of the present invention is that in the control device of the combustion apparatus, comprising an operational amplifier which compares a capacitor voltage charged by a flame rod current, with a reference voltage, thereby to issue an unusual signal, the reference voltage or the capacitor voltage is changed according to the atmosphere temperature by utilizing a thermo sensitive element, thereby the comparing operation is executed correctly irrespective of the atmosphere temperature.

Abstract: A heating system comprising the combination of storage vessels (10, 12) for conventional heating oil and waste oil, respectively, and in which the two storage vessels (10, 12) are effectively sealed apart, one from the other. At the initial stage of heating, conventional heating oil generates temperature of a predetermined amount and the waste oil from vessel (12) is thereafter utilized after having been heated either from a feedback of heat (26, 28) developed by the conventional heating oil from vessel (10) or by a separate electrical resistor element (133), such heating making the waste oil effective as a heating medium. The flows from the two storage vessels (10, 12) containing the waste oil and conventional oil, are pressure controlled (64, 84) so that relief pressure feedback (70, 82) is provided in each distribution network (14, 30).