Abstract: A portable forced air heater includes a one-piece unichassis structure which forms the base and the outer housing of the heater. The outer housing defines an elongated passage having a front end and a back end and which receives a burner assembly. The burner assembly is spaced from the outer housing such that cooling air flows between the combustion chamber of the burner assembly and the outer housing. The burner assembly itself includes the elongated combustion chamber which is shorter than the air passage defined by the outer shell and includes a rear head member which is snapped into place in the inlet end of the combustion chamber. Self-aligning mounting tabs and brackets are formed in both the unichassis and the combustion chamber to significantly reduce the number of parts and to simplify construction.

Abstract: A unitary airflow diffuser for use with a forced-air space heater has a plurality of spurs radially extending from a hub. The spurs include one or more vanes for deflecting the airflow generated by fan blades within the space heater. A nozzle assembly is secured through an aperture in the hub of the diffuser for supplying fuel within a combustion chamber. Brackets can be provided for securing an igniter and a sensor to the airflow diffuser. Mounting tabs are provided on each vane to secure the airflow diffuser to a mounting plate disposed at the input of the combustion chamber. The nozzle ejects the fuel through a central aperture in the mounting plate into the combustion chamber. The mounting plate can have secondary apertures through which air can be diverted, and vanes can be provided on the mounting plates to direct air through the secondary apertures.

Abstract: A gas burner is provided for use on the inlet end of a fire tube, and includes a mixer having attached to it a gas delivery pipe, fuel gas and air being combined in the mixer to provide mixed gas and air. A venturi is secured at its inlet end to the mixer to receive the flow of gas and air, the venturi serving to draw air into the mixer. A burner nozzle is affixed to the venturi outlet end and the burner nozzle and extends within the fire tube. A perforated tube surrounds the mixer/venturi and at least a portion of the burner nozzle. A sound absorbing flame cell housing surrounds the perforated tube. A flame arrestor closes an air inlet opening in the flame cell housing air and serves to permit air to pass into the flame cell housing but prohibits the passage of flame therethrough so that flame is confined within the interior of the flame cell housing.

Abstract: A space heater for heating air from within a room with a heat exchanger connected to a burner and discharging heated air into the room has a room temperature sensor for detecting a room temperature and a controller for controlling the burner with a freeze prevention temperature set to prevent indoor facilities from being frozen. When the detected room temperature drops to or below the freeze prevention temperature, the controller operates the burner and controls the burner with a lower limit for an amount of heat in the burner with which no moisture condensation occurs in the heat exchanger.

Abstract: A gas-fired heating and ventilation system includes a blower which draws air through a recirculation damper from a building and through a direct gas-fired burner from a fresh air inlet. A passive control damper is mounted to bypass air around the burner and to thereby regulate the air flow through the burner for optimum combustion over a wide range of operating conditions.

Abstract: A self-regulating forced-air heater includes a housing in which is located an air passageway. A blower forces air through the air passageway, including into and out of a combustion chamber. A burner disposed within the combustion chamber combusts a fuel and air mixture to heat the air exiting of the combustion chamber. A venturi effect is used to draw the fuel and air mixture through the burner and into the combustion chamber. An adjustable venturi plate assembly is positioned between the blower and the burner, and expands or contracts in surface area to increasingly or decreasingly block the center of the air passageway. A control assembly includes an electronically controlled valve, an electronic controller, an electrical actuator, and a temperature sensor. The electronic controller monitors the temperature sensor, determines if an adjustment is needed in heat output, and in response thereto, adjusts the temperature of the air exiting the self-regulating forced-air heater.

Abstract: A kerosene heater (1) having a pump assembly (106) which includes a piston (113) having a hollow bore (121) through which fuel (98) is routed to the hollow shaft of a fuel atomizer (27). The piston (113) is operated by a cam (117) machined into the shaft (114) of the heater motor (22). Mounted on the motor shaft (114) between the atomizer (27) and the pump assembly (106) is a novel fan (26) combining both low pitched outer blade portions (143) and high pitched vanes (146) near the hub (136) of the fan (26). The air flow near the periphery of the fan tends to be axial while the flow near the hub (136) tends to be turbulent and of lower velocity. A series of rear heads (32,33) downstream of the atomizer (27) tends to separate cooling and combustion air while preheating a portion of the air in the region of the atomizer (27).

Abstract: A high efficiency gas furnace utilizes a unique pre-mix design in combination with a pressurized/high velocity combustion process. The combustion process occurs in a combustion chamber and the high temperature high velocity products of combustion follow a circuitous route from the combustion chamber through finned tubular conduits to an exhaust. Heat from the high temperature high velocity products is transferred to the finned tubular conduits. An air blower assembly forces air across the finned tubular conduits and the combustion chamber to remove the heat from the finned tubular conduits and transfers this heat to a building or an enclosed portion thereof.

Abstract: A gas burner system in which a turbulator disk is arranged between a burner and an opening in a combustion chamber aligned with the burner. The turbulator disk defines a central port and a plurality of peripheral voids adjacent to the central port. A burner flame, produced by ignition of a gas-primary air mixture, together with a quantity of secondary air, may be directed through the central port of the turbulator disk into the combustion chamber. A additional quantity of secondary air may be directed through the voids into the combustion chamber for combustion of the uncombusted gas from the gas-primary air mixture.

Abstract: In a direct gas-fire heater assembly having a generally box-like housing with a grate-like floor with a conventional gas regulator, a gas port mounted within a box-like shroud, the shroud having one side with a predetermined number, shape and size of primary combustion air inflow orifices to direct primary combustion air toward the gas port. A burner is mounted on the shroud over the gas port. The area above the burner and adjacent to it contains an ignition device and flame sense rod as well as a pair of opposed and particularly oriented flame shields on each side of the flame orifice. One each of a pair of opposed baffle-type deflectors is arranged on each side and just above the flame shield so as to form a combustion chamber as well as a path for secondary air flow to a downstream chamber. An additional flame deflector is formed on one baffle-type deflector to deflect the flame toward the blower area.

Abstract: An improved heating system is disclosed for providing heated air to a heated space, preferably using a gaseous fuel as the energy source. The system preferably includes an air heating sub-system, a compact combustion chamber, a separate cold air supply sub-system for conveying cold air from the heated space to the air heating sub-system, a combustion chamber heat exchanger in fluid communication with the cold air supply sub-system for transferring heat thereto, and a separate air circulating sub-system for withdrawing cold circulating air from the heated space. A mixing chamber is provided for mixing heated air from the air heating sub-system with the cold circulating air to provide heated air to the space. The system also preferably includes separate sub-systems for supplying pressurized combustion air and pressurized gaseous fuel to the air heating sub-system and for forcibly conveying exhaust gases therefrom without the need for a draft-type chimney or stack.

Abstract: A high efficiency gas furnace utilizes a unique premix design in combination with a pressurized/high velocity combustion process. The combustion process occurs in a combustion chamber and the high temperature high velocity products of combustion follow a circuitous route from the combustion chamber through finned tubular conduits to an exhaust. Heat from the high temperature high velocity products is transferred to the finned tubular conduits. An air blower assembly forces air across the finned tubular conduits and the combustion chamber to remove the heat from the finned tubular conduits and transfer this heat to a building or an enclosed portion thereof.

Abstract: The room heating arrangement is provided with a radiation tube, connected to a pressure and mixing chamber casing 1, a pipe line system arranged above the room to be heated, the radiation tube being connected, on the one hand, to a return flow chamber 19 with fan 10 and, on the other hand, to a mixing chamber 20 with a flame tube 14 surrounding a burner 2. The pressure and mixing chamber casing 1 is constructed in double-worm form, two cylindrical parts 26, 27 forming the casing and a front and back plate 3, 4 presenting the double-worm form, while the connecting tubes 18, 21 for the radiation tube are connected to the back plate 4. The burner 2 and the drive unit 5 for the fan 10 are arranged on the front plate 3.

Abstract: A heater (independent vehicle heater) which can be operated in a particularly wide range between full load and partial load, e.g., 1:10 to 1:15, is shown. This is achieved by the annular space surrounding the combustion chamber being divided into two partial compartments and by supplying the combustion air to these partial compartments. A control element (back-pressure-controlled control element), which separates some of the air passage openings between the annular space and the combustion chamber from the passage of air, is arranged in the combustion air line.

Abstract: A low NOx burner assembly of a fuel-fired heating appliance is supplied with an air/fuel mixture having a substantially less than stoichiometric air-to-fuel ratio. The air-rich mixture is partially combusted to create primary combustion products disposed within an open inlet portion of a combustor structure having a catalytic converter operatively positioned within an open outlet portion thereof spaced apart from its open inlet portion. A flow of aspirating air is introduced into the combustor structure between the inlet and outlet portions thereof. The aspirating air mixes with the primary combustion products, cools them, and flows with them outwardly through the catalytic converter. This essentially completes the combustion of the remaining fuel within the cooled primary combustion products, and does so at a temperature not appreciably greater than the initial combustion flame temperature to thereby substantially reduce NOx emissions without the use of flame quenching techniques.

Abstract: According to a first aspect of the invention, a combustion heater has an ECU for controlling operations of a glow plug, a battery, a fuel pump, and a blower for supplying air to a combustor. The ECU is responsive to an instruction signal instructing starting ignition of the combustor for starting to cause the battery to apply a first predetermined voltage to the glow plug, and at the same time starting to cause both of the fuel pump and the blower to operate for a predetermined time period, and when ignition of the combustor is detected, the ECU starts to cause both of the fuel pump and the blower to operate, and at the same time starts to cause the battery to apply a second predetermined voltage lower than the first predetermined voltage to the glow plug.

Abstract: An improved air heating apparatus and method of heating an air stream wherein the heating arrangement includes a heater housing with a combustion drum having a burner at one end thereof, the drum being disposed in spaced relation in the housing to extend longitudinally along the length thereof, a heat exchanger longitudinally extending in the space between the combustion drum and housing to receive combustion products from the combustion drum, an air stream blower positioned to pass an air stream over the heat exchanger in the space between housing and drum and to pass air from opposed ends of the combustion drum including the burner at one end to promote an extended burner flame substantially along the combustion drum length.

Abstract: The present invention is a direct fired unit heater which includes a lower combustion chamber which communicates with an upper fan assembly which mixes combustion products with ambient air and discharges this laterally from the unit. The fan assembly has two cylindrical fans each with different critical speeds. One motor drives both cylindrical fans and is adjustable so that at a first higher speed it is within the operating range of both fans. At a lower operating speed, it is only within the operating range of the upper cylindrical fan. The upper cylindrical fan acts to pull in room air and discharge this. Thus, the blower operates continuously thereby destratifying the room air. When the burner operates, the motor speed is increased to act within the operating speed of the lower fan assembly. This lower fan assembly thereby pulls in the combustion products and discharges these along with the ambient air. The size of the cylindrical fans are designed to provide appropriate mixing for a direct fired unit.

Abstract: Substantially all available heat from a combustion gas stream is extracted by passing it through a cool, porous heat sink, which is thereby heated, and then releasing that heat into a cool air stream blown through the same porous heat sink in a second step (preferably in the opposite flow direction). The heat sink absorbs substantially all the available heat of combustion rather than merely scavenging what would otherwise be stack losses. The invention provides an improved means of recovering virtually all the available heat produced by combustion of a fuel gas. It permits recovery of the heat lost in a conventional single-zone furnace. The improved heat recovery is achieved without contamination of the ambient air with exhaust gas residues as occurs in direct-fired systems, and without incurring the problems of corrosion and waste disposal inherent in two-zone indirectly-fired systems.

Abstract: A furnace is provided for combusting liquid or gaseous fuel which has a combustion assembly with an internal cavity that has a mixing chamber and a combustion chamber. A flame tube is disposed intermediate the mixing chamber and the combustion chamber. The combustion assembly has an outlet which is adapted to exhaust the gases which result from combustion of the air-fuel mixture. An ignitor rod for igniting the air fuel mixture is also provided.

Abstract: A flueless, portable low nitrogen oxides emissions, low carbon monoxide emissions space heater having a fuel chamber with a fuel inlet and a fuel distributor. The fuel inlet generates a swirling fuel flow within the fuel chamber. A primary air inlet generates a counter-swirling primary airflow with respect to the swirling fuel flow in a primary air chamber. The fuel distributor discharges the swirling fuel flow into the counter-swirling primary airflow thus forming a fuel/air mixture. An ignitor ignites the fuel/air mixture. A combustion chamber is sealably secured to and in communication with the primary air chamber. The combustion chamber wall has a plurality of secondary air supply holes. An intermediate shell surrounds the combustion chamber wall and forms a space between the intermediate shell and the combustion chamber wall. A secondary air inlet is in communication with the space between the intermediate shell and the combustion chamber wall. An outer protective shell surrounds the intermediate shell.

Abstract: Embodiments of gas-fired appliances which generate sufficient electricity to be self-powered include water heaters, space heaters, air conditioning units, and electric power and steam cogeneration systems. In such apparatus, gas is burned in a porous ceramic surface combustion burner. The high temperature surface of the burner includes a narrow band quantum emitting substance such as a rare earth metal oxide and preferably ytterbium oxide. Relatively shorter wavelength radiation from this quantum emitting surface illuminates photovoltaic cells having an absorption spectrum matched to the emission spectrum of the burner surface for generating sufficient electricity for powering the appliance. An infrared absorbing filter removes relatively longer wavelength radiation which would otherwise heat the photovoltaic cells. The cells are cooled, preferably by a portion of the utility fluid heated by the appliance.

Abstract: An air control assembly for a fuel burner having a combustion chamber and a nozzle includes a control device which controls the amount of air that flows into the burner and an assembly dependent on fuel pressure which actuates the control device. A fuel inlet path is provided for communicating fuel to the nozzle and a fuel return path is provided for communicating excess fuel away from the nozzle. The assembly dependent on fuel pressure includes a piston and rod device adapted for reciprocation in a piston chamber. A nozzle block is provided in which the piston chamber is defined and the nozzle is supported.

Abstract: An apparatus for supplying heated air to an air stream including a first air flow duct having an inlet and an outlet, a blower for forcing air through the duct to the first duct outlet, and a second air flow duct having an inlet, an outlet, and a burner chamber between the inlet and outlet, with the second duct outlet connected to the first duct downstream of the blower for drawing atmospheric air through the second duct by air flow through the first duct. A gas burner in the burner chamber, an apertured refractory wall positioned across the second duct downstream of the burner, and a refractory liner for the inner surface of the burner chamber between the burner means and the apertured wall.

Abstract: A compact forced air heater comprises a combustion chamber mounted in a housing, a burner module mounted across a back open end of the combustion chamber adjacent a back wall of the housing for producing heated air in the combustion chamber, an air intake in a front wall of the housing, and a high speed (3000 rpm) forced air blower mounted between the combustion chamber and the housing front end wall. The burner module includes a flameholder plate having a central primary air hole and circular rows of staggered secondary air holes surrounding the primary air hole. A flamespreader plate is mounted on the flameholder plate opposite the primary air hole, and an elongated right-angle burner tube, having a flattened locating-and-orienting end and at least one burner orifice in a sidewall of the tube, is located on an opposite side of the flameholder plate with the burner orifice aligned with the primary air hole and the flamespreader plate. An ignitor and a thermocouple are also mounted on the flameholder plate.

Abstract: A heating and ventilating system has a space heating device, in which heat is generated by combustion of a fuel, and which heats air for a building. A heat exchanger has one side through which exhaust air from the building flows to the exterior. Through the other side of the heat exchanger, fresh, makeup air for the building is supplied, and this may pass through the heater. An exhaust conduit from the heater, for combustion products, opens into the exhaust air line connected to the one side of the heat exchanger. This enables heat to be extracted from air leaving the building and further heat to be extracted from the combustion products, this heat being transferred to the incoming air in the heat exchanger.

Abstract: The invention relates to heating apparatus for heating confined spaces, and particularly for heating passenger compartments in automotive vehicles and the like. The heating apparatus comprises a combustion device having means for supplying and mixing fuel and combustion air, and an outlet for combustion gases, and further comprises a heat exchanger which is connected to the outlet of the combustion device and which is intended for heat exchange between the combustion gases and a heating medium delivered to the space to be heated. According to the invention the combustion device incorporates a catalytic reactor for catalytic combustion of at least part of the fuel-air mixture, and a thermal reactor which is located between the catalytic reactor and the combustion gas outlet and which is intended for final combustion of the fuel-air mixture at least partially combusted in the catalytic reactor.

Abstract: A cleaning apparatus for a burner on a motor vehicle energizes a heater of a fuel atomizer for heating and atomizing fuel, when fuel supply to the fuel atomizer is shut off and the speed of rotation of the engine on the motor vehicle is higher than a prescribed level, so that carbon deposits on and in the fuel atomizer will be burned out and removed.

Abstract: A connecting device for supplying power to equipment in heating devices, particularly, auxiliary vehicle heating devices, which connecting device serves to commonly and centrally supply a combustion motor, a control device, a circulating pump, a solenoid valve, an ignition spark unit, a flame monitoring device, and, if utilized, a preheating device for a burner nozzle assembly. All connections and connecting devices, like plug connectors, are housed and combined in a common, central connecting component which can be secured on a flange of the heating device, and can be attached to a part of the heater housing. Appropriately, the connecting component is designed in the form of a housing and contains the electrical connections to be actuated in the form of printed circuit boards, or the like.

Abstract: A direct-fired make-up furnace comprises a cabinet which houses an air blower. A gas fired burner located in a sloped passage, which is formed by walls of a return air compartment and a by-pass air compartment, radiates heat at an angle relative to the blower. The return air compartment substantially blocks direct radiation of the burner. An exit opening of the by-pass air compartment is located between the burner and the blower.

Abstract: An apparatus having a heating chamber, (combustion chamber) a heat storing means and heat transferring means of the kind used in households, commercial furnaces, heaters, boilers, etc., having a heating chamber which is spherically arranged; with ports for receiving fuels and a valve for regulating the internal pressure and temperature, allowing for excessive heat to be exhausted into a secondary heat recovery manifold. The spherical heating chamber allows the heat to radiate uniformly. Said heat is stored by mantle material. Said mantle being entirely surrounded by a crust layer and insulating means and an outside protective covering. The apparatus also having means for transferring the stored heat for heating purposes as is generally in common use.

Abstract: A forced air heater (10) includes a removable burner module (26) in which all of the burner components are mounted on a common support plate (42) to facilitate mounting of the burner module in the heater and removal of the burner module from the heater for servicing. An elongated burner tube (46) has a closed flattened end (50) receivable in a location-and-orienting bracket (76) to locate a single burner orifice (52) in a sidewall of the tube in proper position with respect to a pancake flame-spreader plate (78). A gas valve (44) and ignition device (58) also form part of the burner module 26. A combustion chamber (24) is of essentially box-shaped construction, with one open end (36), and includes an inclined baffle plate (40) which enhances mixing of combustion products and intake air in the chamber. A forced air blower (28) is mounted adjacent a heated air discharge opening (36b) of the combustion chamber (24).

Abstract: A portable hot air circulator comprises concentrically mounted cylindrical members, the inner member being closed at its upper end to form a cup-like structure designed to mount over a conventional liquid fuel heater in closely-spaced relation. Air is forced downwardly through an annular passageway between the cylindrical members by a fan mounted through the top of the outer cylindrical member which is closed to form a plenum space between the tops of the concentric cylinder members. The fan is shielded by a louvered hood member, and spacer clips accomodate the mounting over the liquid fuel heater.

Abstract: A direct air heater using the air to be heated as combustion air includes means for maintaining a constant flow of air across the burner. The heater also includes means for recirculating inside air and means for controlling the flow of inside air, preferably, to maintain a constant pressure in the space being heated.

Abstract: A portable LP gas heater includes a combustion chamber the discharge end of which is open and unobstructed and the inlet end of which is defined by a rear head plate having a central primary air inlet into which projects, to a limited degree, a cylindrical fuel nozzle. The projected extremity of the nozzle which positions within the combustion chamber mounts a transversely disposed baffle which is parallel to and spaced preferably about one inch from the rear head plate. Fuel exits from and about the nozzle immediately adjacent and upstream of the baffle. The baffle has a size which permits it to be introduced to and removed from the combustion chamber by way of the primary air inlet. The rear head is further distinguished by a single group of apertures located adjacent its outer periphery in a substantially ring-like pattern.

Abstract: A warm air blowing heater includes combustion equipment for burning fuel, and an air duct provided at a position away from a portion directly above the combustion equipment for blowing air from the heater into the room. The combustion equipment includes a burner chimney provided above a burner, and a reflecting plate is provided behind this burner chimney. The radiation heat of the combustion equipment is radiated directly and is also reflected on the reflecting plate to heat the room. The air duct does not disturb the rise of the combustion exhaust gas of the combustion equipment to form a smooth rising exhaust gas stream. When the air is blown from the air duct toward the front of the heater, the high temperature air in the upper portion of the heater is sucked. This high temperature air is mixed with the air blown from the air duct to allow the heater to blow warm air into the room. The blower motor may suck the air in the room and supply it to the air duct.

Abstract: Apparatus is disclosed for operating a gas furnace system (100) having an air intake (102) for supplying external air into a sealed chamber (110) for input to a gas burner assembly (118). Exhaust air from within the combustion burning chamber (140) is applied through an exhaust duct (170) directly into an environment (174) which is external to the furnace system (100) but which is still within the environment to be heated. The furnace system (100) also includes a conventional fan limit assembly (142) wherein the typical high limit setting is substantially decreased so that a blower fan (160) is activated at lower than normal temperatures. In addition, the conventional gas furnace burner is replaced with a burner assembly (118) having substantially small burner ports (130).

Abstract: An improvement of the space heating system delivering a composite comprising of heated outdoor air, unheated outdoor air and recirculated indoor air into a building to counter a natural infiltration of outdoor air by modulating the composite air supply delivered to the interior of a building.

Abstract: A power gas burner of the gun type. The burner embodies an air tube that is mounted on the appliance with which the burner is to be used. Primary and secondary air is supplied to the air tube by a blower of the turbo-compressor type that is driven by a motor through an adjustable speed drive. Fuel gas is supplied to the air tube through an eductor tube. Gas is supplied to the eductor at regulated pressure through a metering orifice. The discharge end of the eductor is open and is located on the axis of the air tube and in the throat of a venturi that is also mounted on the axis of the air tube. Air supplied by the blower flows at high velocity through the throat of the venturi on the exterior of the eductor, resulting in a reduction in pressure in the venturi at the discharge end of the eductor. This primary air is mixed in the venturi with gas discharged from the eductor.

Abstract: A combustion device has a negative pressure combustion burner and an ejector air flow generating mechanism and is designed so that the warm air flow rate is approximately proportional to the combustion rate. The device is simple in construction, and by controlling the warm air flow rate it is possible to adjust the heat output of the device while maintaining the temperature of warm air at a constant value. The device disclosed herein is particularly suitable for use as an air circulation type room heater.

Abstract: An air-heating gas burner has a housing which includes a fuel gas supply passage and an air supply passage which open into a combustion zone defined between walls which extend downstream of outlets for the gas and air. Combustion products emerging from said combustion zone are confined between further walls which extend downstream to a location at which the combustion process is substantially complete. The burner is intended for mounting in an air conduit and the combustion products emerging from between the further walls have a particularly low content of oxides of nitrogen.

Abstract: A fuel gas burner produces a short fan-shaped flame and has primary utility in oil-to-gas furnace conversions. The burner includes swirl generating blades disposed in an annulus between a burner barrel carrying the bulk of the combustion gas and a mixing tube carrying approximately a 1.1 air/gas mixture. The blades induce a violent, turbulent action to the combustion gas to encourage formation of the short flame. The flame is preferably formed with a fan shape.

Abstract: A method for converting a direct fired gas heating apparatus from one having a constant volume discharge air flow characteristics to one having variable volume characteristics by the use of an internally recirculating volume discharge air flow increment.

Abstract: Air heater having an outer manifold and an inner combustion chamber with a common longitudinal axis, and a burner in the rear end of the chamber, of which the manifold has an air inlet in its rear end and a constricted air outlet in its front end, and the combustion chamber has in its peripheral wall a plurality of ports through which to divert part of the air from the manifold into the chamber for its heat-up by the burner flame therein and discharge through the open end of the chamber.

Abstract: A portable forced air heater having a flame holder positioned between a blower and a combustion chamber. The flame holder has a plurality of holes or openings formed therein to stabilize and control the combustion process within the combustion chamber. The holes or openings are arranged in such manner that the percentage of total flame holder area devoted to holes or openings increases at a general uniform rate as the distance from the center of the flame holder increases. The flame holder also has openings formed therein to support various components of the heater in order to provide a relatively small compact forced air heater.

Abstract: A pulse combustion heater is described and includes a combustion chamber and at least one exhaust pipe forming a resonant system with the chamber. In one aspect, the heater has a three part housing, upper and lower parts of which are concrete castings and define respectively an air cushion chamber and an exhaust chamber of the heater. A center section forms part of a boiler sub-assembly which isolates the exhaust chamber from the air cushion chamber. In another aspect, a unitary gas cushion chamber sub-assembly is described.

Abstract: An oil burner for distillate fuel including a blower and air guiding elements producing a rapidly whirling pattern of combustion air close to the burner nozzles to produce an extremely hot fireball close to the nozzles. The fireball, once ignited, provides reliable continuous ignition of the entering fuel, obviating the usual requirement of continuous electrical ignition, and permitting the use of low voltage for the initial ignition. The blower produces an excess of air over that needed for combustion, and the excess air cools the combustion chamber externally to obviate any necessity of forming the chamber of stainless steel, cast iron or the like. When the burner includes a plurality of burner nozzles intended for use singly or simultaneously, automatic means are provided for supplying the necessary carefully regulated amounts of combustion air.

Abstract: The present device provides an air duct means disposed between the top end of the heat exchanger of a furnace and the entry port into the flue pipe of the furnace. An electrical blower means is coupled to said duct means to draw hot air therethrough which would otherwise go out to the atmosphere through the flue. The hot air drawn by the blower is redirected to heat, or assist in heating, the building to which the furnace is directing heat, or heat some other facility. An electrical control circuit is connected to the blower means and controls the blower means such that if the furnace is burning fuel, the blower cannot be turned on. The blower can only be turned on after a predetermined time has elapsed from the time that the fuel burning has terminated, so that combustion gases which otherwise would pass through the flue and which might contain harmful ingredients therein, will not be redirected to be used as a source of heat.

Abstract: A heater of particular use in drying grain has a fluid fuel burner located axially in a housing through which air is drawn and a coaxial convergent guide ring downstream of the burner. One or more openings in the housing admit ambient air for mixing with the heated air downstream of the guide ring. The heater permits of supply of air at, for example, 5000 to 35000 ft.sup.3 /min at a temperature of 10.degree. F above ambient.