Abstract: A combustion apparatus (1) has a burner (11) configured to burn combustion gas, a heat exchanger (12) disposed below the burner (11), and a combustion fan (13) configured to supply air for combustion, wherein the combustion apparatus performs post-purge operation in which the combustion fan (13) is activated for a predetermined period of time after combustion operation of the burner (11) stops, and intermittent blower operation in which activation and deactivation of the combustion fan (13) is repeated a plurality of times at predetermined intervals after the post-purge operation ends.

Abstract: The invention provides a balanced drying system, comprising an air supply and exhaust main pipeline, and at least two groups of drying units; the drying units each comprises a unit air supply fan and a drying oven, the drying units each is provided with a unit air inlet and a unit air outlet, the drying oven is provided with a drying oven air inlet and a drying oven air outlet, and all of the groups of the drying units are disposed in pairs at intervals on the air supply and exhaust main pipeline via the unit air inlet and the unit air outlet, the unit air inlet is connected with the drying oven air inlet, and the unit air outlet is connected with the drying oven air outlet. The invention has the advantages of concise and stable system, simple adjustment, low exhaust air volume, low energy consumption and the like.

Abstract: A heating, ventilating, and air conditioning (HVAC) system includes a furnace having a primary heat exchanger and a secondary heat exchanger, where the primary heat exchanger and the secondary heat exchanger form a heat exchange relationship between an airflow and an exhaust gas, and where the primary heat exchanger is positioned upstream of the secondary heat exchanger, a burner configured to generate the exhaust gas, a sensor configured to monitor an ambient temperature, and a control system configured to receive feedback from the sensor, compare the feedback to a threshold, operate the furnace in a first mode when the ambient temperature exceeds the threshold, and operate the furnace in a second mode when the ambient temperature is at or below the threshold, where the furnace operates above a condensation temperature when in the second mode, such that the exhaust gas does not condense when operating in the second mode.

Abstract: A gas heat sub-base for use in conjunction with a PTAC or similar HVAC terminal unit, the sub-base having a housing with a front side, back side, top and bottom all defining an interior space. The top is configured to mate with the bottom of the PTAC unit. The sub-base also includes a plurality of air intake louvers on the front side of the housing and a heat exchanger located within the interior space of the housing. The gas heat sub-base is separate from, but is integrated with, the PTAC unit. A heating and cooling unit includes a PTAC unit with the gas heat sub-base.

Abstract: The exemplary embodiment is directed to a heat and energy recovery assembly, system and method. The heat and energy recovery assembly and system may include an insulated chamber for effectuating heat and energy exchange between a primary heat recovery exchanger and the reaction products of fossil fuel combustion gases, waste products, and air. The heat and energy recovery assembly and system are particularly useful on furnace systems.

Abstract: An integrated heating unit operates in a first heating mode, in which the heat of combustion gases is transferred to return air, and a second heat recovery mode, in which the heat of exhaust air is transferred to fresh air. The heating unit of the present invention utilizes the same heat exchanging unit and fans to transfer the heat from the combustion gases to the return air and to transfer heat from the exhaust air to the fresh air. The exhaust air is recovered from a select group of rooms, e.g. kitchens and bathrooms. A secondary heater can also be provided in the integrated unit in the form of a fireplace for providing an alternate or an additional source of the combustion gases.

Abstract: Disclosed herein is a dryer having a heater-integrated intake duct capable of reducing thermal loss and preventing overheating of the dryer. The dryer includes a support panel having a through-hole, an intake duct communicating with the through-hole, a drum into which air flows via the through-hole, a heater disposed inside the intake duct to heat the air flowing into the drum, and a heat exchanging part transferring heat of the heated air into the drum.

Abstract: A hot air heater has a housing having formed therein an inlet port for sucking room air and an outlet port. A circulation fan, a burner, and a heat exchanger which causes to flow combustion gas from the burner through an inside of the heat exchanger are housed in the housing. The room air sucked by operation of the circulation fan into the inlet port is heated by the heat exchanger for blowing forward as hot air out of the outlet port. A supporting plate is disposed to support the heat exchanger inside the housing. In order to limit the temperature increase in the housing by heat transmission through the supporting plate, and in order to improve the thermal efficiency, the supporting plate is provided with radiating fins. Preferably, the radiating fins are made up of cut-and-raised pieces formed in the supporting plate.

Abstract: In an in-wall heater, in which control equipment 11, 12 is disposed in a side space 10 on one lateral side of a combustion housing 2 within an outer case 1 and an exhaust duct 15 is disposed in a side space 13 on the other lateral side of the combustion housing 2, the cooling performance of each of the side spaces is increased and noise due to a sucked-in sound of room air can be reduced. In a side plate portion of the outer case 1 on both lateral sides, an air intake opening 7, which is vertically long, is provided in a position in a front side portion exposed to a front of a room wall. Each side space 10, 13 within the outer case 1 is formed in a ventilation flue on the suction side where the room air from each of the air intake openings 7 is conducted into the warm air fan 9.

Abstract: An apparatus for extracting heat from a heat source comprising a housing having a first end with a first opening and a second end with a second opening. The housing includes an internal compartment therein and the first end of the housing is connected to said heat source. A channel extends from the housing for providing access to the internal compartment. A hollow conduit is positioned within the internal compartment extending between the first opening and the second opening. A plurality of members are positioned on an exterior surface of the conduit and along the length thereof. The members are able to absorb heat from within the conduit and release the absorbed heat into the internal compartment creating heated air. The apparatus includes a means for drawing air through and expelling air from said conduit and means for moving said heated air out from said internal compartment to a second compartment. The apparatus is activated via means connected to each of the drawing means and the moving means.

Abstract: An air heating system includes an internal combustion engine powered by combustible gas. Such engine having at least one cylinder and a horsepower determined by size of space to be heated. A source of such gas is in fluid communication with the engine for communicating a requisite amount of gas to such engine. An air intake is disposed in fluid communication with a source of air and the engine for communicating air to the engine. A flywheel is connected to the engine for at least extracting heat therefrom. An air chamber surrounds the engine for directing hot air extracted therefrom to such space to be heated. A heat exchanger is disposed in the air chamber for extracting heat from exhaust gases exiting the air chamber and heating air being returned to system. An exhaust is connected to the air chamber and to outside air for exhausting cooled air from system.

Abstract: A heat exchange system and method for heating outside air provided to a structure are disclosed. The system uses and recovers heat from waste products that are being exhausted from the structure. A heated products source generates heated waste products as a result of combustion. An exhaust duct passes the heated waste products through a heat exchanger before exhaustion from the structure. An intake duct that supplies fresh outside air to the structure also passes through the heat exchanger. The heat exchanger couples the exhaust duct and the intake duct and transfers otherwise unused heat from the waste products to the outside air to increase the overall efficiency of the heated product source.

Abstract: A method, apparatus and system are provided for heating fluids using a waste heat recovery arrangement adapted for application to existing heat exchange systems that generate waste heat and/or heated exhaust gases. The method, apparatus and system utilize the heater control arrangement of the existing heat exchange system to control the heating of the fluid and a pumping arrangement, for example, a hydrokinetic pumping arrangement, to circulate the fluid to be heated from a location outdoors to the heat exchange system.

Abstract: A heat exchanger is mounted external to a section of flue pipe or is an integral part of a section of flue pipe. The heat exchanger preheats a domestic hot water supply and boosts the return water temperature prior to reentry to the furnace coil. The heat exchanger reduces fuel use, pollution and wear of the furnace and burner. A typical heat exchanger installation includes an oil or gas burner located on a furnace or boiler having a flue pipe leading to a gaseous outlet, such as a masonry chimney. A short vertical flue section leads to a draft-regulating damper. The flue heat exchanger may be a coil of tubing wrapped around flue section, such that the tubing picks up heat from the heated flue gasses. Preheated water exits from the heat exchanger.

Abstract: A balanced building ventilation system that employs a fireplace as an element of the ventilation system. The fireplace includes a firebox, and an exhaust gas flue is connected to the firebox for exhausting gas from the firebox to the outdoor ambient. A ventilation channel conveys outdoor ambient air into the building interior. A motor-driven draft inducer is connected to the exhaust gas flue for forcing exhaust gas flow out to the outdoor ambient. A motor-driven blower is provided for forcing ventilation airflow through the channel to replace building interior air lost to exhaust gas flow.

Abstract: The need to maintain the quality of air in a home has become more of a problem in new high efficiency tight houses so that governmental regulations are being proposed for a minimum change of fresh air. If too much cold outside fresh air is introduced into such homes at a single source, the room with the fresh air is usually too cold and/or unbalanced. The present invention avoids cooling any one room while maintaining heat efficiency. When the home has a gas fireplace, the exhaust gases are preferably directed through an air-to-air cross flow heat exchanger which preheats the quality air passing into a forced air furnace system. In modified embodiments of the present invention, make-up quality air is mixed with the room air and heated in the heat exchanger of the fireplace. The preheated room air from the fireplace is preferably connected to the supply/return of a forced air furnace system and distributed to all rooms to provide uniform heating.

Abstract: A heater comprises an enhanced-surface area heat transfer vessel which is situated co-axially in a hot flue gas plenum. The plenum is formed by dual-wall heating jacket. Liquid flowing through the jacket is heated co-currently by the flue gas before the preheated liquid is conducted to the top of the vessel for countercurrent heat exchange therein before discharge from the bottom of the vessel. Hot flue gas flowing through the plenum is directed circumferentially by one or more spaced and perforated ring plates placed across the plenum annulus between the jacket and the vessel. Aluminum construction of the vessel and jacket with protective coatings contribute to a lightweight heater for either floor or even wall mounting. The heater is conveniently implemented in a hydronic heating system, a potable hot water system or a combination of both.

Abstract: An object of the present invention is to provide a hot air space heater that is capable of blowing hot air out of a whole wide hot air outlet provided at a front plate of a frame of the heater while making the heater smaller in depth. A burner is arranged so as to be close to one side of the frame. A heat-discharge portion is constructed on the burner. On the other side of the frame, an accessory-receiving space is defined side by side with the heat-discharge portion. Between the hot air outlet provided at the front plate of the frame and a wall portion positioned in front of the accessory-receiving space, an extended air feed space is defined. Air fed by a fan into a duct structure is heated while passing through between a plurality of heat-exchange pipes. The air is blown against a front wall of the duct structure and a plate-like member of an air guide provided on a rear side of louvers. Heated air blown against the front wall flows out forward through a first air flow path above the plate-like member.

Abstract: The need to maintain the quality of air in a home has become more of a problem in new high efficiency tight houses so that governmental regulations are being proposed for a minimum change of fresh air. If too much cold outside fresh air is introduced into such homes at a single source, the room with the fresh air is usually too cold and/or unbalanced.

Abstract: A forced air heating system has a heat regulating unit assembled therewith, the heating system comprising a furnace having fuel burner and a flue pipe for outlet gases. The heat regulating unit has a metal flue conduit with a flue gas inlet and a flue gas outlet connected to the flue pipe in proximity to the furnace to form a portion of the flue pipe. An elongated casing surrounds the flue conduit and defines with the flue an annulus in which a series of equispaced metal fins extend radially from the flue conduit to the casing to define chambers containing a heat-absorbing material such as metal wool. The heat regulating unit functions as a heat-sink to absorb heat from the hot fuel and a heat source gases for return to the furnace by conduction and convection.

Abstract: A heat exchange system and method for heating outside air provided to a structure are disclosed. The system uses and recovers heat from waste products that are being exhausted from the structure. A heated products source generates heated waste products as a result of combustion. An exhaust duct passes the heated waste products through a heat exchanger before exhaustion from the structure. An intake duct that supplies fresh outside air to the structure also passes through the heat exchanger. The heat exchanger couples the exhaust duct and the intake duct and transfers otherwise unused heat from the waste products to the outside air to increase the overall efficiency of the heated product source.

Abstract: A heat exchange system and method for heating outside air provided to a structure are disclosed. The system uses and recovers heat from waste products that are being exhausted from the structure. A heated products source generates heated waste products as a result of combustion. An exhaust duct passes the heated waste products through a heat exchanger before exhaustion from the structure. An intake duct that supplies fresh outside air to the structure also passes through the heat exchanger. The heat exchanger couples the exhaust duct and the intake duct and transfers otherwise unused heat from the waste products to the outside air to increase the overall efficiency of the heated product source.

Abstract: Flame-effect heating apparatus comprises a housing with walls defining an air duct extending therethrough. Simulated fuel is supported by the housing, externally of the duct, and at least one flame-effect generator is disposed in the duct. A light source is provided in the housing to illuminate both the simulated fuel and the flame-effect generator. A mirror is supported by the housing so that light reflected by the flame-effect generator is incident thereon. A wall of the housing which defines the air duct, is formed as a viewing screen on which light reflected by the mirror falls, the viewing screen being positioned higher than the simulated fuel. An electric fan causes air to flow through the air duct, so causing operation of the flame-effect generator, and a heat exchanger disposed in the duct warms air passing thereover.

Abstract: A heat exchanger is mounted external to a section of flue pipe or is an integral part of a section of flue pipe. The heat exchanger preheats a domestic hot water supply and boosts the return water temperature prior to reentry to the furnace coil. The heat exchanger reduces fuel use, pollution and wear of the furnace and burner. A typical heat exchanger installation includes an oil or gas burner located on a furnace or boiler having a flue pipe leading to a gaseous outlet, such as a masonry chimney. A short vertical flue section leads to a draft-regulating damper. The flue heat exchanger may be a coil of tubing wrapped around flue section, such that the tubing picks up heat from the heated flue gasses. Preheated water exits from the heat exchanger.

Abstract: A heating system for a building that includes a furnace having a water jacket surrounding a burner unit. Heated water is circulated from the water jacket to a heat exchange system in the building such as radiators and the water is returned to the water jacket through a return conduit to be reheated. Water from the jacket is also circulated through supplemental conduit through a gas tube water heat exchange apparatus located at the exhaust flue from the furnace for recovering heat from the exhaust gases. Water heated from the exhaust gases returns to the primary circulation system. More specifically, water flows from the cooler portions of the water jacket and/or the return conduit of the main circulation system to the gas-to-water heat exchange unit. Water flows from the gas-to-water heat exchange unit to the relatively warmer portions of the jacket and/or to the primary conduit that delivers water from the jacket to the heat exchange system of the building.

Abstract: A heat exchange system and method for heating outside air provided to a structure are disclosed. The system uses and recovers heat from waste products that are being exhausted from the structure. A heated products source generates heated waste products as a result of combustion. An exhaust duct passes the heated waste products through a heat exchanger before exhaustion from the structure. An intake duct that supplies fresh outside air to the structure also passes through the heat exchanger. The heat exchanger couples the exhaust duct and the intake duct and transfers otherwise unused heat from the waste products to the outside air to increase the overall efficiency of the heated product source.

Abstract: A heat exchange device for harnessing heat from an exhaust vent is provided including a furnace having a main inlet for receiving cooled air suctioned from a living area, a heating mechanism for heating the cooled air suctioned from the living area, a main outlet for delivering air to the living area which is heated by the heating mechanism, and an exhaust vent coupled to the furnace for expelling air associated with the generation of heat by the heat mechanism with such expelled air not being fit for channeling to the living air via the outlet. Next provided is a housing which divides the exhaust vent into a lower portion and an upper portion. The housing has an auxiliary inlet in communication with the living area for receiving the cooled air therefrom and an auxiliary outlet in communication with the living area for expelling air thereto. Lastly, a heat transfer mechanism includes a pipe formed in the shape of a helix.

Abstract: An improved heat exchanger containing a hollow cylindrical pipe casing having a plurality of apertures formed on the surface. A lower elbow pipe is secured to a stove outlet pipe and to the hollow cylindrical pipe casing. The lower elbow pipe functions to receive hot air discharged from a stove. A plurality of receiving elbow pipes are positioned within the apertures that are formed in the hollow cylindrical pipe casing that function to receive cool air from an outside source. A plurality of inner U-shaped pipes are positioned within the hollow cylindrical pipe casing and are secured to a corresponding receiving elbow pipe. Each inner U-shaped pipes is positioned within one of the plurality of apertures that is formed in the hollow cylindrical pipe casing. A plurality of outlet pipes are also contained in the device and are secured to a one of the corresponding plurality of inner U-shaped pipes. Each outlet pipes functions to release warmed air into a room.

Abstract: A heat recovery apparatus for increasing the efficiency of a furnace having a cold air return, a burner, a hot air outlet, and a hot air exhaust. The heat recovery apparatus comprising a finned coiled heat exchanger located in the exhaust and having a water inlet and a water outlet. The water outlet connected via a silicone tube to a second water inlet on a core heat exchanger located in the cold air return. The core heat exchanger having a water outlet connected via second silicone tube to a water reservoir tank. The water reservoir tank containing water and a pump submerged within the water. The pump having a third water inlet and a third water outlet. The third water outlet being connected via a third silicone tube to the water inlet of the coiled heat exchanger. The heat recovery apparatus increasing the efficiency of a non-high efficiency furnace.

Abstract: In a dwelling having a forced warm air type central heating system in which the source of heat is the hot gas products of combustion in a furnace, ambient fresh air is introduced into the dwelling to improve the quality of air in the dwelling by a fresh air input duct to the fresh air input of a relatively low temperature flue gas to the fresh air heat exchanger so that the fresh air is warmed and the fresh air output of the heat exchanger is connected by a duct to the forced warm air heating system so that the warmed fresh air is entrained with the air in the system. In a preferred embodiment, the flue gas to fresh air heat exchanger is attached to a section of the furnace flue pipe that is covered by a thermally conductive gas barrier and includes an enclosure for enclosing the outside barrier covered surface of the section of the furnace flue pipe forming an annular space between the gas barrier and the enclosure through which the fresh air flows and is warmed by heat from the flue gas.

Abstract: A heating system comprises an oven located above a solid fuel stove, a chimney for receiving combustion gases from the solid fuel stove, and a heat exchanger in the chimney for transferring heat from the combustion gases to a flow of water. A heat exchange passage adjacent a water tank receives combustion gases from the stove and transfers heat from the combustion gases to water in the water tank. A damper is adjustable for controlling the flow of the combustion gases to the chimney and to the heat exchange passage.

Abstract: A fireplace furnace heating system for a structure having a firebox for combustion of fuel, preferably coal. A heating unit is disposed proximately to, and preferably surrounds the firebox. Conduits carry interior air from remote locations to the heating unit. The heating unit is preferably a multi-walled, chambered structure to define numerous air passageways. Air delivered from the conduits to the heating unit must travel through the air passageways. The proximate disposition of the heating unit to the firebox heats the heating unit and the air travelling therethrough. The heating unit has vents for returning the heated air to the interior of the structure. A blower is included for forcible moving the air through the heating unit and back to the interior. Conduits are also provided for supplying fresh air from the exterior to the firebox to fully combust fuel in the firebox. A motorized blower is included to forcibly move the combustion air. Also included is a tempering tank for storing water.

Abstract: Heating apparatus for heating an environment comprises one or more heat exchange conduits (A, B, C, D, E, F, 6, 8) located in the flow path of primary heated fluid (F1-F2), and a device (4) for inducing a flow of air in each conduit, each conduit being adapted to carry air into, through and out of a heat flow path to the environment (2), the arrangement being such that, in use, air within the conduits progresses from a cooler to a hotter part of the heat flow path, and the conduits are spaced closer together toward the downstream direction of the flow path to improve the efficiency of heat exchange between the primary heated fluid and secondary air in the conduits.

Abstract: A supplementary hot water heating system which transfers to a hot water tank heat from exhaust gas in the furnace stack which would otherwise be wasted. When the water in the supplementary heater core is heated to a desired temperature, normally closed valves, one connecting the heater core to the cold waterline and the other connecting the bottom of the hot water tank to a drain, are simultaneously opened and remain opened until the supplementary heater core is again filled with cold water from the cold water line.

Abstract: A gas fire space heater which can be an insert for an existing fireplace or a free standing unit is described. The device consists of a gas burner with radiants disposed within a housing. The products of combustion are collected in a first plenum, directed through a concertina heat exchanger into a second plenum, and from the second plenum up a flue. Air to be heated is collected by a blower and circulated countercurrently to the products of combustion through the heat exchanger, around the housing, and into the space to be heated. Air to be heated is supplied to the blower from an outside vent, and an inside vent. The outside vent is controlled by a one-way suction damper and the inside vent is controlled by a manual damper. The two vents form a T at the fan inlet and control of the manual damper then controls the amount outside and inside air supplied to the blower.

Abstract: An improved burner head for a forced air furnace is disclosed which includes a burner tube fitted with gas nozzles, air flow openings, and a flame tube. At least one radial opening is provided between the end of the burner tube and an end of the flame to allow exhaust gas recirculation via a ribbed ring secured between the burner tube and the flame tube upstream of the radial opening but downstream of the gas nozzles and airflow openings. The ribbed ring includes ribs protruding radially inward crosswise to the longitudinal axis of the burner head. The burner head allows for a substantial reduction in NOx, to a level on the order of less than 50 ppm.

Abstract: A condensate drain system for a furnace incorporates a collector and blower housing assembly mounted above a secondary condensing heat exchanger with condensate ports between the blower housing and the collector housing positioned to assure flow of all condensate from the exhaust flue and the blower housing to the collector housing. A pipe extends downwardly from the collector housing to the condenser outlet manifold so that all condensate ultimately flows to the condenser outlet manifold and can be discharged to a drain by a single tube.

Abstract: Apparatus utilizing waste heat from a furnace or the like to heat water for any desired purpose or to supplement a conventional heating system. In its illustrative embodiment, the invention provides a heat recovery device adapted to be interposed as a unit in a flue duct to absorb heat from the hot gases and products of combustion escaping through the flue duct, connections being provided for a positive, controlled flow of a heat absorbing liquid through the device. The device includes an inner flue section, a liquid flow coil around the flue section and an outer sleeve relatively insulated from heated components and joining the parts into a device capable of being stored, handled and installed as a unit.

Abstract: A prefabricated zero clearance fireplace includes a combustion chamber having a front opening, a glass door sized and shaped for positioning over and sealing the opening and a guide system for guiding vertical movement of the door between a lowered position over the opening and a raised position. The guide system includes tracks that are inwardly offset at their lowermost ends so that the door seals the combustion chamber without friction as the door is raised and lowered. Counterweights permit the door to be easily raised and lowered. For safety, the counterweights cause the door to automatically raise if it is pushed outwardly from the inside. The door is hinged for pivoting outwardly about a vertical axis in the lowered position. An optional motor can be provided for raising and lowering the door. A convection chamber surrounding the combustion chamber permits circulation and heating of room air.

Abstract: A unique heat exchanger device which is mounted in the flue of a forced air furnace is disclosed. A plurality of copper tubes are retained in a substantially parallel and equidistant relationship by means of end plates. A plurality of circular metallic fins are positioned on the copper tubes and serve as heat radiating surfaces. Cross tubes are provided within the copper tubes permitting the passage of heated air therethrough. The tube assembly is covered by a perforated shroud permitting air at room temperature to pass therethrough and to circulate among the heated copper tubes. An exhaust manifold is provided on the perforated shroud to permit connection of the device to the cold air return on the furnace.

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: Improvements in fireplace systems include several features some of which are separably usable in other heating apparatus. The features include a barometric damper adaptor, a grate structure, a manner of mounting hollow grate tubes in a fireplace assembly, an improved combustion chamber assembly, a combined damper and ducting system, a revised plenum system for a fireplace or the like and a tempering system cooperative with such a unit.

Abstract: A reflective heat conductor is presented in the form of a grill having a plurality of individual cells bounded by reflective bare metal surfaces. The grill has an arcuate shape complementary to the object, such as a stovepipe, on which it is located. Heat transfer is effected by substantially increasing the conductive area of the surface of the object on which it is mounted, by reflecting radiant heat energy emitted by the surface, and, in the case of a stovepipe, by also increasing turbulence within the stovepipe to reduce stack velocity and produce more complete burning.

Abstract: A process and apparatus for removing moisture from smoke produced in a chemical reaction, such as a combustion reaction, by circulating outside air in heat-exchange relationship with smoke at a point near the chamber where the smoke is produced, thereby heating the air and cooling and partially dehydrating the smoke. A portion of the air which is thus heated is passed in further heat-exchange relationship with smoke and is then directed toward a smoke discharge stack where it is mixed with the partially dehydrated smoke.

Abstract: A flue gas/combustion air heat exchanger for a furnace. The furnace includes a combustion chamber that burns a mixture of fuel and combustion air to produce heat for a comfort zone. The resulting products of combustion, along with any waste heat not transferred to the zone, pass through a flue duct before venting to atmosphere. Incoming combustion air is discharged across the relatively hot flue duct before it enters the combustion chamber. In passing across the hot flue duct, the incoming air is preheated by waste heat of the combustion products. The heat exchange relation between the incoming combustion air and the combustion products within the flue duct enables the furnace to recover waste heat that would otherwise be lost if the combustion products were free to discharge to atmosphere before giving up a portion of their waste heat to the incoming combustion air.

Abstract: A heating system comprising a firebox defining a combustion chamber that is substantially sealed from the atmosphere. The system includes a flue for conducting combustion gases from the combustion chamber. A first duct surrounds the flue and defines an inner passageway with respect thereto. A second duct surrounds the first duct and defines an outer passageway. An inlet means is provided for introducing ambient air into the outer passageway. The air in the outer passageway is drawn through the inner passageway by a negative pressure in the combustion chamber. The ambient air in the inner and outer passageways is heated by heat transmitted from the flue. This heated ambient air is then introduced in the combustion chamber to improve the efficiency of combustion.

Abstract: Fresh air make-up apparatus for a furnace located in an enclosed building comprises an elongated diffuser housing positioned adjacent the furnace, with the housing having an inlet in communication with fresh outside air and a pair of outlets, one being connected to the cold air return of a forced air furnace at a point substantially upstream of the heat exchanger, and the other outlet leading to the room. The outlet leading to the cold air return provides fresh make-up air for the building, while the opening leading to the room provides both a means for diffusing and preheating the fresh air supplied to the cold air return and a means for providing fresh air diffused with warm room air to the combustion in the combustion chamber of the furnace. The apparatus also includes a removable filter for removing contaminants from the fresh air. The apparatus can include a heat exchanger for preheating the fresh air with warm air from the warm air duct of the furnace.

Abstract: This invention provides a device for meeting the demand of a forced-air furnace for make-up air in a building, the make-up air being available from a duct leading from outside the building. The device takes warm air from the hot air plenum of the furnace and returns the air to the return air plenum. This flow of air is caused by a differential pressure between the two ducts when the furnace is operational and operates a valve element which normally closes the duct carrying outside air and opens to permit flow of this air in response to the passage of warm air between the hot air and return plenums.

Abstract: An air purification system for use with an air conditioning apparatus which includes an air circulation system having supply air flow to a given area and return air flow for drawing air from that area. The air purification system includes an inlet and an outlet. A conduit communicates the inlet with the air circulation system for drawing therefrom a portion of the air passing therethrough. A conduit communicates the outlet with the air circulation system downstream of the inlet for returning the portion of the air back to the circulation system after it has passed through the air purification unit. A superheating conduit also communicates between the inlet and an exhaust of the air conditioning apparatus, such as the chimney of a furnace.

Abstract: A device for evacuating into the ambient air combustion products from a condensation boiler, in which at least one downstream section of the conduit for evacuating the combustion products is coaxial to the conduit for admission of the combustion air necessary for the burner. Means are provided for returning to the outside a fraction of the air collected in said admission conduit. The downstream section of the conduit for evacuating the combustion products, the coaxial section of the admission conduit and the means for returning to the outside a fraction of the collected air define a first heat exchanger. Means also are provided for diluting the combustion product with the fraction of collected air, the dilution means being located in the vicinity of the opening for suction of the combustion air and for rejection of the combustion products into the ambient air.