Abstract: A system for heating the air in the room containing a fireplace includes a heat exchanger mounted at the top portion of the combustion chamber of the fireplace to extend across the chimney flue opening and a fan for circulating room air through the heat exchanger in heat exchange relationship with the combustion gases passing from the combustion chamber in a vortex flow through a heat exchange passage in the heat exchanger to the chimney flue opening. There are preferably provided a pair of the heat exchangers mounted in side-by-side relationship to conform with the rectangular shape of the plan view of the fireplace.

Abstract: An electro-mechanical, dual tube and plug device for on-line monitoring of performance losses due to reduced conductivity of a non condensing heat exchanger resulting from micro-bio fouling of the surfaces of said heat exchanger and for detecting change of heat transfer resistance of individual heat transfer tubes. The dual tube and plug assembly includes a first flow assembly tube and a second temperature assembly tube attached to the discharge end of a heat exchanger for providing accurate measurement of temperature and cooling water flow. The first flow assembly tube includes a tube having an inner chamber, including a flow sensor a temperature sensor for measuring discharge water temperature. The second temperature assembly tube plugs the inlet and the outlet of a heat transfer tube immediately adjacent to the flow assembly tube and includes a plurality of temperature sensors in the plugged empty heat transfer tube.

Abstract: A method for identifying a leaking earth tap heat exchanger includes measuring an electrical resistance between the electrically conducting tubing of the earth tap heat exchanger and the surrounding soil or water to determine if the electrically insulating layer has an undesired opening in a portion thereof thereby exposing an adjacent portion of the electrically conducting tubing to the soil or water as indicated by a relatively low electrical resistance. Each earth tap heat exchanger preferably comprises electrically conducting tubing having an electrically insulating layer covering an exterior thereof. The method may also be used to test the integrity of the electrically insulating layer to avoid corrosion as may be caused by direct contact between metallic tubing and adjacent soil or water. Apparatus aspects of the invention are also disclosed.

Abstract: A gas or a fired radiant energy heating system wherein a burner is connected to a long radiator tube. Means are provided for balancing the heat output over the length of the tube thereby lowering the temperature at the burner end. In one embodiment, this entails use of a length of insulator in the tube adjacent the burner and a length of turbulator near the exhaust.

Abstract: A method and apparatus to heat a forced-air supply utilizing hot waste gases in a flue. A flue closure housing is supported by a frame that is arranged to surround an opening in the chimney. The housing supports a heat exchanger having side walls formed of plates with a space between the plates being sealed by end walls to form a flow space for a forced-air supply. The heat exchanger is sealed to a flue closure plate forming part of the flue closure housing. The heat exchanger receives a supply of cold air from a motor-driven blower coupled to a header. Heated air from the heat exchanger is directed by a hot-air discharge header through an opening in the flue closure housing.

Abstract: An air heater for recovering energy from process exhaust gases and the like includes a heat exchanger disposed in the flow of exhaust gases, a blower for supplying an independent flow of air to be heated in the exchanger and the control system including dampers, driving mechanisms and thermostats for adjusting air flow in order to maintain substantially constant heated output air temperature. One of the dampers is disposed at the outlet of the blower and adjusts, by a thermostat an appropriate drive mechanism, the volume of air supplied by the blower based on outlet temperature. A pair of dampers are connected in oppositely acting (face and bypass) fashion and adjust the proportion of air passing through or bypassing the heat exchanger, again based on the temperature of the outlet air as sensed by a thermostat.

Abstract: A device for reclaiming heat from stove pipes and the like. A semi-circular shaped hollow enclosed housing with a highly thermal-conductive concave surface is mounted contactingly to surround approximately one-half of the circumference of the stove pipe. The concave surface is formed to contact the pipe at a maximum number of points along that surface. The hollow interior of the housing contains thin multi-surfaced projections which are integral with the concave surface and conductively transfer heat from the stove pipe and concave surface to heat the air in the housing. A fan blower is attached via an air conduit to an entrance opening in the housing. When turned on, the blower pushes the heated interior air out a plurality of air exit openings in the ends of the housing and brings in lower temperature outside air for heating.

Abstract: Heat exchanger means for extracting heat from the flue gases of a warm air furnace is in the form of a tube wound spirally to define a first passageway wherein ambient air is heated by the flue gases passing through a second passageway between segments of the first passageway for the ambient air, the tube being provided with a deflector directing the flue gases through the second passageway and a shroud for controlling exhaust gases passing through and leaving the convolute tube.

Abstract: A method and means for extracting heat from an exhaust stack under highly corrosive and fluctuating conditions. An in-line exhaust gas heat exchanger having selective dual concentric exhaust paths and having a plurality of longitudinal structural stringers to insure against weakening of the exhaust stack. A plurality of heat exchanger coils are located in the outermost exhaust path and means is provided for fully draining the liquid contents thereof. Temperature control method means is provided for regulating the temperature of fluid within the coils due to exhaust stack temperature fluctuations for controlling critical dew point situations.

Abstract: A heat extractor system for a furnace, said furnace including a burner with a chimney that is connected but is normally not in operation. Instead, the furnace is connected to a vent in parallel with the chimney through a draft-inducing arrangement including a water spray in which water is heated and circulated to a point where the heat from the water is utilized. Due to the parallel arrangement of the vent and chimney, if the vent fails to operate, it will function in a fail-safe manner, with the combusted gases from the burner leaving through the chimney.

Abstract: A coupling between a stainless steel exhaust manifold of a recuperative heat exchanger and a plastic flue pipe. The internal integrity of the manifold is maintained by spot welding a mounting bracket to the outside thereby defining a slot between parallel portions of the bracket and the manifold. The flue pipe inserts through coaxial circular apertures in the bracket and the manifold. A shoulder of an annular protrusion on the outside of the flue pipe presses against an O-ring seated in an inwardly directed step of the circular aperture in the manifold thereby providing an airtight seal. The flue pipe is secured in the described position by a bifurcated retainer clip slid down into the slot thereby engaging portions of the opposite shoulder of the annular protrusion.

Abstract: A heat saving device is provided for use in connection with the flue pipe of a stove, furnace, or similar heater. Instead of being exhausted directly into the atmosphere through the flue pipe, hot exhaust gases and other combustion products pass through a heat transfer chamber. An open-ended tube forms the inside wall of the chamber so that heat from the gases and other combustion products passing through the chamber is transferred to the useful air flowing through the tube. A removable shroud open at one end and baffled at the other partially surrounds the outer wall of the heat transfer chamber in spaced relationship to the outer wall, permitting flow of useful air through the space thus formed. The useful air flowing through this space is preheated by heat transferred through the outer wall and subsequently entrained by and mixed with air being blown through the inner tube by a fan.

Abstract: An energy recovery system for an incinerator. Hot flue gases from the incinerator are discharged into a vertical stack and the lower end of the stack is connected through an auxiliary conduit to a heat exchanger, such as a steam or hot water boiler. An induced draft fan draws the hot flue gases through the conduit and boiler to generate steam or hot water and a damper is located within the conduit. A fuel burner is connected in the conduit and operates to supply heat to the boiler during periods when the incinerator is not operating. A first flow sensing mechanism is located in the conduit upstream of the boiler, while a second flow sensing mechanism is positioned in the stack downstream of the connection of the stack and the conduit.

Abstract: A device for heating fluid with the exhaust gases from a furnace or stove includes a coiled fluid conduit mounted within the exhaust conduit and means such as baffles for directing the exhaust gases through and around the coiled fluid conduit. In one embodiment, the fluid in the coiled conduit is water from a cold water source which, after passing through the coil and being heated by the exhaust gases, flows to a water heating tank in a pre-heated condition.

Abstract: A flue gas heat recovery apparatus for a forced air type furnace of the type having a furnace heat exchanger, a return air duct and a heated air duct, and a blower for passing air from the return air duct over the furnace heat exchanger to the heated air duct. The heat recovery apparatus includes a secondary heat exchanger mounted in the return air duct having its inlet connected to the outlet of the furnace heat exchanger and an induced draft fan having its inlet connected to the outlet of the secondary heat exchanger and its outlet connected through an outlet flue pipe to the chimney. A vane is mounted in the outlet flue pipe in the path of flow from the induced draft fan and is moved between a closed position when the fan is not operating, to an open position when the fan is operating, and a switch is operated by the vane to operate the burner control after the induced draft is in operation.

Abstract: An apparatus for heating a fluid, as air, having a housing surrounding a heat transfer chamber. A casing having a combustion chamber is located in the heat transfer chamber. A motor driven fan mounted on the housing operates to supply air to the combustion chamber and move air through the heat transfer chamber. Fuel, as waste oil, is metered to the combustion chamber and burned. The air supplied to the combustion chamber moves the burning fuel in a circular pattern to promote combustion of the fuel adjacent the casing thereby heating the casing. The air moved through the heat transfer chamber picks up heat from the hot casing. The heated air is discharged through an open grill into the environment surrounding the apparatus.

Abstract: The present invention discloses a heat recovery apparatus, for example for use in a fireplace having a firebox with an upwardly directed flue of selected peripheral configuration communicating with the firebox and having an atmospheric outlet.

Abstract: A heat exchanger and vaporizer adapted for mounting on an existing flue for utilizing heat which is otherwise lost and for providing moisture for space heating and conditioning. The heat exchanger and vaporizer includes a central stack for unimpeded transport of flue gases; a casing, with air inlet and outlet, enveloping the stack; a vaporizor contained within the casing for efficient heat transfer and for room conditioning; and a motor-fan unit for producing an airflow through the casing. The vaporizer is in the form of non-corrosive heat conductive helical tubing for maximizing heat transfer in a given volume, for maintenance free use and for convenience in assembly. The vaporizer is provided with a plurality of vapor vents on its upper surface and a pour spout located externally of the casing.

Abstract: A heat retrieving device is disclosed which directs cool incoming fresh air down a duct within a flue pipe. Hot gasses in the flue pipe heat the incoming air, warming it sufficiently so that it can be discharged directly into a room that is to be heated, thus supplementing the existing heating system. In the preferred embodiment, the upper exterior portion of the exhaust flue is an inverted L-shape that is mounted on a rotatable bearing. A weathervane having an air scoop on one end and both a main vane and a pilot vane on the other end is securely mounted in the horizontal portion of the flue pipe, causing it to rotate into the wind. The upper portion of the duct within the flue pipe is also bearing-mounted and terminates into the fresh air scoop which exits from the flue pipe. Said air scoop is preferably located directly below the air scoop of the weathervane. As the air scoop of the weathervane turns into the wind, the air scoop of the fresh air intake duct also turns into the wind.

Abstract: A gas furnace is described which is of conventional design except for the means by which combustion air is supplied to the burner assembly. The gas furnace includes a cabinet having a burner assembly, heat exchanger and flue provided therein. The flue is in communication with a chimney extending upwardly from the building. An enclosure extends around the chimney and is spaced therefrom to define an air passageway. The upper end of the air passageway is in communication with the atmosphere outside of the building. Duct work connects the lower end of the air passageway with the combustion air opening formed therein so that combustion air for the burner assembly will be drawn from the outside atmosphere downwardly through the air passageway rather than from the interior of the building. As the air passes downwardly through the air passageway, the air is heated by the chimney.

Abstract: A circulating air wood burning heating stove/fireplace combination has a combustion chamber that is in the form of a shell defined by inner walls of the stove and a rearwardly disposed air outlet manifold. Spaced outer auxiliary back and top walls and the corresponding shell walls form therebetween air passages through which ambient air is recirculated into the room over the manifold. The manifold is provided with a plurality of spaced heat conductive metal strips disposed about its periphery. Several manifold embodiments include one or more finned air heating conduits which extend therethrough. A blower fan or pair of blower fans are used to circulate air through the air passages and in heat transfer relationship to the manifold. A valve, damper, and linkage control arrangement regulate the heat output and may be used upon starting of the fire to clear a column of cold air from the flue.

Abstract: Disclosed is an add-on boiler that has an insulated cover covering a housing that carries a finned heat-recovery coil. The add-on boiler is mounted on the casing of a heating device to heat water in the coil with heat transferred by conduction and radiation. The insulated cover maintains the heated water in the coil at a high temperature to prevent the internal operating temperature of the heating device from dropping below the critical temperature at which creosote forms from the flue gases.

Abstract: A device for heating air by flue gases in steam boilers and furnaces, comprises a supply flue, sections mating therewith, and a device for protection of heat-exchange tubes against abrasive wear arranged in the flue. Each section comprises heat-exchange tubes attached to tube plates. The device for protection of the heat-exchange tubes against abrasive wear incorporates at least one screen formed by corrugated sheets facing each other and mating along the lines of contact of sheet convex portions, whereby cells are made up.

Abstract: Heat recovery attachment in combination with the combustion gas discharge duct of a gas-fired or oil-fired heating apparatus having a liquid or air circuit, substantially comprising a heat exchanger having a supply and a discharge connection for the combustion gases to be passed therethrough, and a fan which encourages combustion gases to flow through the heat exchanger. The heat exchanger extends at most partly into the combustion gas discharge duct, and means are present to direct the exit gases, after heat exchange, obliquely upwards into the combustion gas discharge duct in such a manner that they form a gas barrier extending substantially across the transverse section of the combustion gas discharge duct.

Abstract: A recuperative furnace and method for heating wherein the recirculation air blower directs the return air upwardly first to a recuperative heat exchanger and then to a second heat exchanger operating from the heat of combustion. The flue gases are routed directly to the recuperative heat exchanger where a portion of the products of combustion condense. Accordingly, the recuperative heat exchanger not only provides sensible heat transfer from the flue gases but also recovers a portion of the latent heat of vaporization. The second heat exchanger transfers heat from a solution to the recirculation air. The solution flows through a closed loop between the second heat exchanger and a heat transfer module which includes the burner.

Abstract: A fuel-fired fluid heating appliance, such as a gas-fired boiler (FIG. 1) is provided for heating a fluid such as water circulating in a central heating system. The boiler includes a flue 4 for discharging the combustion products, e.g. exhaust gas, to atmosphere by way of a heat exchanger 8 incorporated within a portion 6 of the flue 4 external of the boiler housing 1. The heat exchanger 8 is provided with an inlet 16 to receive water from a return flow pipe 36 and an outlet 17 to discharge the water to the inlet 35 of the boiler primary heat exchanger 3. The heat exchanger 8 (FIG. 2) is provided with a number of ducts 18 along which the exhaust gas travels to transfer its heat to the water circulating within compartments 29 to 33 within the heat exchanger housing 15. The external portion 6 of the flue 4 is disposed at an angle of 20.degree. downwardly to the horizontal so that any exhaust gas condensing in the heat exchanger 8 flows down the flue base 9 to a discharge spout 10 and collector weir 11.

Abstract: This device is a heat capturing, recirculating economizer ventilator, which is sheet metal and is in kit form, to be assembled by the user, for being applied to standing-fireplaces, stoves, and the like. Primarily, it consists of a housing encapsulating a segmented helical configuration surrounding a vertical smooth flue pipe, which automatically forces room ambient air by virtue of a motor driven centrifugal blower, spirally downward on a double path toward and through diffusers, for the purpose of distributing heated air into a space to be heated.

Abstract: A water heater of the combustion type having a collecting assembly for collecting the drain water resulting from combustion to prevent corrosion of components of the heater by the drain water.

Abstract: A metal recuperator is described as having an exterior casing with a replaceable inner housing which forms with the casing a pair of separated fluid passageways through which two fluids, at different temperatures, are circulated into heat exchanging relationship. Special seals are provided to allow relative movement between the casing and the housing while sealing the passageways from each other and the ambient atmosphere.

Abstract: Apparatus for recovering heat comprising an encapsulating outer wrapping having near opposite ends an air discharge opening and an opening adapted to receive an air intake blowing device; an inner corrugated galvanized sheet metal flue core; and two semi-circular baffles mounted in valleys of the inner core corrugations.

Abstract: A flue gas heat recovery apparatus for reconstituting thermal energy normally lost through the venting of flue gases from a heat liberating plant is disclosed. The apparatus can be employed with forced air or hydronic systems and includes a compressor which draws hot gases from the exhaust flue through a first heat exchanger located in a cold fluid return to the plant, thereby transferring thermal energy from the gases to fluid (typically air or water) flowing in the return duct. The compressor operates to substantially elevate the pressure and temperature of the flue gases passing therethrough and discharges them through a second heat exchanger located in the return duct upstream of the first heat exchanger to further transfer thermal energy from the gases to the fluid flowing therein. Gases exiting the second heat exchanger are directly vented to the atmosphere or, alternatively, are first filtered to remove particulate matter.

Abstract: A heat exchange device is adapted to recover heat from the fire box of a wood burning stove or the like for heating ambient air in a room or other enclosed space. The heat exchange device is adapted to mount in a recess in a stove top in place of a lid which is normally supplied with the stove. The device according to the invention includes heat exchange means which extend into the fire box of the stove below the top surface thereof. The heat from the heat exchange device is transmitted into a main cavity of the device where the heat is transferred to air forced through the main cavity by a blower mounted to an outside surface of the device. Air exit means are provided on a surface opposite to the surface on which the blower is mounted to provide a passage for heated air into the room or other enclosed space to be heated. The device may also include a top mounted isolated handle for ease in handling the device such as for moving from one area to another.

Abstract: A safe, practical and inexpensive method for saving heat units on modern forced warm air heating furnaces, this method employs a heat exchanger designed by the furnace manufacturer to fit each different size and type of their models. The heat exchanger is interposed directly on the furnace heat exchanger outlet and on through the piping to the flue or chimney. Air circulation through the heat exchanger is provided by the furnace blower by directing air from the warm air supply plenum, with its positive pressure, through the heat exchanger and terminating in separate supply run with a high volume of air which requires no external power to accomplish it. The heat exchanger will be provided with test openings for thermometer readings at the inlet and outlet of flue gas travel through the exchanger. A manual damper may be locked into proper position to restrict air circulation flow if necessary to maintain proper flue gas exit temperature.

Abstract: A fire-guard device is provided for heating a room by convection using the heat from a conventional radiation heat source. The device includes a plurality of pipes in which all adjacent pairs of pipes are pivotably interconnected together. Each pipe is mounted in its own piece of tubing. Each piece of tubing has hinge eyes joined thereto for use in providing the pivotal connection between pipes. The pieces of tubing and hinge eyes form a threshhold for the relatively cool air flowing to the device over the floor of the room in which the device is located.

Abstract: The invention relates to recuperators used mainly with industrial furnaces, which is provided with a radiation heat exchanger and a convective heat exchanger arranged one behind the other. These known types of recuperators are usable to exploit the waste heat of flue gases only with very low efficiency and have a voluminous and complicated structure.The improvement of my invention is in that the convective heat exchanger has a central heat exchange part and at least one conduit for blowing air on the bottom surface of the central heat exchanger part.The recuperator according to this invention has a longer endurance, a much higher effectiveness and a more simpler, smaller construction.

Abstract: The present invention provides apparatus for utilizing heat in the flue of the furnace as a heat exchanger and a humidifying source which comprises a flue with a conduit spaced from and concentric with the flue. Means are provided for forcing air from the upper part of the conduit downwardly between the flue and the conduit in a direction opposite to the normal flow of the gases in the flue. Further means are providing for applying moisture to the outer surface of the upper part of the flue within the conduit and above the means for forcing air into the conduit. The heated and humidified air passes downwardly in the conduit and outwardly therefrom and may be connected to the plenum of the furnace. Baffles may be supplied within the flue and within the conduit in order to increase the turbulence of the air and thus increase the heat exchanger which is provided by the system.

Abstract: A flue gas heat recovery system for use in conjunction with a forced hot air furnace, such system having two conventional heat exchangers, one located in the flue leading from the combustion chamber of the furnace to the chimney, and the other in the cold air chamber of the furnace adjacent the blower fan. Such heat exchangers each have a core connected into a hydraulic circuit which contains an electrically driven circulating pump controlled by a thermal device having a heat actuated switch located in the upper portion of the heat plenum in the furnace.Such switch is connected into an electric circuit adapted to activate the blower fan and circulating pump simultaneously. The core of the heat exchanger located in the flue of the furnace absorbs a substantial portion of the heat in the exhaust gases which would otherwise be lost to the atmosphere, and utilizes such heat to increase the temperature of the air supplied to the intake of the blower fan in the cold air chamber of the furnace.

Abstract: A flue gas heat recovery apparatus is employed with a system of appliances such as a gas furnace and hot water heater, each having separate exhaust gas flues. The apparatus includes a gas-to-liquid heat exchanger in thermal communication with the two flues to simultaneously extract heat therefrom and a liquid-to-gas heat exchanger disposed within the furnace cold air return duct. A pump circulates water between the exchangers in response to a control signal to employ the recovered heat to preheat the cold air entering the furnace through the cold air return duct. A hysteretic control circuit monitors exhaust gas temperature and provides for system operation between high and low gas temperature limits. In the preferred embodiment of the invention, a furnace blower override feature is employed to energize the blower during periods of pump operation.

Abstract: A solid fuel burning modular stove fabricated from a plurality of metal assemblies includes a first assembly provided with a combustion chamber, an air duct at the lower front of the chamber communicating with the ambient air, a louver member inside the air duct varying the degree of admittance of air through the duct, flue pipe means for exhausting combustion products from the stove, a plurality of fire brick lining the floor, rear and side walls. Vertical ducts are positioned along the rear and side walls having inlet openings at their bottom and outlet openings at their tops, heated air rises through the ducts and discharges into the ambient air. A second assembly to be attached to the bottom of the first assembly comprising horizontal channel means in communication with the vertical duct inlets providing a blower to force outside air through the vertical ducts.

Abstract: A heating apparatus includes at least one combustion air inlet, a reverse-draft hearth having a grill positioned within a hearth plate, an ash receptacle for recovering combustion wastes, a fume outlet, a combustion chamber positioned under the reverse-draft hearth, and a heat recovery device. A heat transport and exchange fluid is adapted to be fed through the heat recovery device, and it circulates through the device in order to recover heat generated in the hearth. The heat recovery device also includes at least one casing positioned beneath the hearth, over the ash receptacle, and which is spaced from the walls of the heating apparatus. The rear portion of the casing is connected to the hearth plate so as to block combustion gases so that the combustion gases will pass over and thereafter under the casing prior to leaving the apparatus via the fume outlet.

Abstract: An improved high performance ventilation system for application with relatively small temperature-controlled structures for recovering a high percentage of sensible and latent thermal energy from the exhausted air for return via the fresh air stream. Two matrices of thermally absorbent, expanded honeycomb material are alternately interconnected with fan driven supply and exhaust paths via a valve device to store energy in one matrix while retrieving it from the other. The matrices, valve and fans are contained within a single compact highly portable housing which can be installed on the floor, beneath the ceiling and on the roof of the intended structure. Constant air flow direction is maintained in the ventilated area. The valve may be thermostat controlled. The housing is manufactured with a modular design allowing final on-site assembly in a number of varying configurations.

Abstract: A heat extractor for picking up waste heat from flue gases is disclosed. The extractor attaches to the stove pipe of a furnace or stove. Air is introduced into the extractor in a spiral flow pattern which is reversed after the air is heated. Air flows into the room from the extractor in a 360.degree. pattern.

Abstract: An air-circulating assembly includes a motor driven fan and a shroud supporting the fan. The assembly is characterized by a support structure for extending about and engaging an existing stove pipe for removably attaching the shroud to the exterior of the stove pipe so that the fan moves ambient air past the stove pipe to heat the ambient air.

Abstract: A flue heat reclaimer is constructed to be mounted on the exterior of a flue duct of a heater and provide a spiral-shaped heat transfer passage extending around the flue duct. A fan causes air to flow through the heat transfer passage so that the temperature of this air is elevated by reason at its extended heat transfer relationship with the flue duct.

Abstract: A heat saving and recovery system which includes a rectangular housing insert for a furnace flue gas duct incorporating a coil carrying a heat transfer fluid such was water. The coil communicates with a cold return conduit or other heat transfer device in a forced flow system to transfer heat from the chimney conduit to the return fluid intended to be heated by the furnace.

Abstract: An apparatus and method for utilizing the heat of waste gases by exhausting the same at the head of a flue from a source into a heat extractor where the hot gases are caused to move and turbulate about heat exchanger walls to release their heat to such walls before being exhausted downward to the atmosphere so that fluids moved through the heat exchanger may be heated to perform useful work.

Abstract: An attachment for a building furnace which contains a combustion unit inside of an air plenum. The attachment is inserted as a replacement section of the smoke flue. The jacketed chamber acts as a heat exchanger, preheating incoming combustion air. The outer end lower portion of the jacketing chamber receives a fresh air duct from the outside of the building. A duct from the outer end upper portion of the heat exchange chamber leads into the lower portion of the combustion unit plenum at the burners. Attached to the smoke flue, and between it and the outer portion of the chamber, are longitudinally-oriented channeled elements for transferring sensible heat. A return duct from the heated living area leads into the furnace, terminating at the inlet of a blower in the bottom of the furnace. The outlet of the blower is upward into the space surrounding the combustion unit. Such space also joins above the latter to lead upwardly into the heated living area.

Abstract: One exchanger unit comprises a length of exhaust pipe tube having a plurality of smaller heat exchange tubes which extend diametrically through the exhaust pipe tube. Each of the heat exchange tubes is canted slightly longitudinally of the exhaust pipe tube and the heat exchange tubes are disposed in a helical configuration to force the exhaust gases to swirl through the exhaust pipe tube. The heat exchanger units can be disposed in a furnace exhaust pipe or can be arranged between inlet and outlet plenums which are connected in a furnace exhaust pipe or the like.

Abstract: A method and apparatus to heat a forced-air supply utilizing hot waste gases in a flue. A flue closure housing is supported by a frame that is arranged to surround an opening in the chimney. The housing supports a heat exchanger having side walls formed of plates with a space between the plates being sealed by end walls to form a flow space for a forced-air supply. The heat exchanger is sealed to a flue closure plate forming part of the flue closure housing. The heat exchanger receives a supply of cold air from a motor-driven blower coupled to a header. Heated air from the heat exchanger is directed by a hot-air discharge header through an opening in the flue closure housing.

Abstract: A heating vent is disclosed in which A T-shaped housing of light weight sheet metal is inserted in the plastic vent hose of an electric clothes dryer to provide passages through which the dryer is vented either outdoors through the vent hose or indoors through a sock-like filter having its open end stretched over the lateral outlet of the housing according to whether a pivoted valve member in the housing is in its summer or winter position.