Abstract: Disclosed is an air heating apparatus including a burner configured to cause a combustion reaction, a main passage, through which water flows while circulating, a heat exchanging device configured to receive heat from combustion gas generated by the combustion reaction and heat the water flowing along the main passage, a heating heat exchanger configured to receive the water heated by the heat exchanging device and exchange heat with the air for heating, a fan configured to send the air to the heating heat exchanger, and a hot water discharge port connected to the main passage such that the water heated by the heat exchanging device is discharged to an outside of the main passage.

Abstract: A gas-fired atmospheric pressure steam humidifier having high efficiency and ultra-low NOx(3) emissions is disclosed. In some examples, the gas-fired humidifier can have an efficiency of greater than 90 percent and a NOx(3) output of less than 20 parts per million (ppm). In one aspect, the humidifier includes a secondary heat exchanger having a first heat exchange section for pre-heating combustion air and a separate second heat exchange section for pre-heating make-up water, wherein the first and second heat exchange sections are in heat transfer communication with exhaust gases generated by the gas-fired burner and combustion blower assembly. In some examples, the first heat exchange section includes orifices for enabling flue gas recirculation.

Abstract: A stabilized flotation platform that is used for supporting supplies for those enjoying time in the water. The uniqueness is the stability provided by its construction such that materials contained on or in the device do not spill into the water.

Abstract: A forced flue heater draws out combustion gas using a burner fan installed downstream from a heat exchanger to prevent a burner fan motor from being heated to high temperature. The forced flue heater blows air to an air channel using a blower fan, and warms the air using the heat exchanger contained in the air channel. The pressure upstream from the heat exchanger is higher by a value corresponding to the resistance of the heat exchanger. The blower fan contained in an outer case draws in the surrounding air to lower the pressure inside the outer case. A partition separating between the inside and the outside of the air channel has an air outlet located upstream from the heat exchanger. This allows the cool air upstream from the heat exchanger to flow outside the partition. The air is then used as cooling air for cooling the burner fan motor. This structure prevents the burner fan motor from being heated to high temperature when the burner fan is heated to high temperature.

Abstract: A heat recovery device and an alignment film curing system. The heat recovery device can be provided outside a heating device, and it includes a first recovery unit including a first chamber and a first communicating pipe that is provided in the first chamber. The first chamber has a first gas inlet and first gas outlet, a first waste gas inlet and a first waste gas outlet, and the first communicating pipe is arranged in a winding way and connected between the first gas inlet and the first gas outlet in an enclosed way. The first gas inlet is connected to a gas supply pipe of the heating device, the first gas outlet is connected to an intake pipe of the heating device, the first waste gas inlet is connected to an exhaust pipe of the heating device, and the first waste gas outlet is configured to discharge waste gas.

Abstract: According to various aspects, exemplary embodiments are disclosed of direct fired heaters including premix burner technology and/or feed forward control loop modulation via inlet air temperature.

Abstract: A heater and a method of its use are configured for use at cold operating temperatures. The heater has a supply line for transporting a volume of fuel between a fuel tank and burner. An inline heater is supplied in a supply line for the burner, and preferably is located upstream of a fuel filter for filtering the fuel so as to prevent wax condensation in the filter. The heater also has a return line that normally returns unused fuel from the burner to the heater, hence reducing the volume of fuel that needs to be heated by the heater and reducing system power requirements. The heater may be thermostatically controlled to maintain the temperature of the heated fuel to a value that is at or above a temperature required for good fuel atomization but below a flashpoint of the fuel. A valve is provided in the return line to permit diversion of the returned fuel to the fuel tank during a purge operation at initial startup.

Abstract: A vented, gas-fired air heater especially designed for temporary heating applications includes an improved burner design providing effective air and gas mixing and efficient burning in the combustion chamber. Highly efficient heat exchanger including corrugated heat exchanger panels provides enhanced heat transfer characteristics.

Abstract: A stove includes a combustion chamber for producing heat, a thermoelectric device thermally coupled to a hot source and a cold source, a battery, a fan electrically connected to the thermoelectric device and the battery, and a controller configured to monitor the battery and thermoelectric device and configured to direct the fan be operated from power provided from the battery when power produced from the thermoelectric device is insufficient to power the fan. The stove can have an associated heating plate, and the walls of the combustion chamber can be configured to reflect heat onto the heating plate.

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

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

Abstract: A vented, gas-fired air heater especially designed for temporary heating applications includes an improved burner design providing effective air and gas mixing and efficient burning in the combustion chamber. Highly efficient heat exchanger including corrugated heat exchanger panels provides enhanced heat transfer characteristics.

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

Abstract: A furnace system 10 including a combustion vessel 12 having an outlet end 19 and at least one aperture 20, 22 extending into an interior area 14 defined by the combustion vessel. The furnace system 10 includes a flue duct 42 coupled to the outlet end 19 and in fluid communication with the interior area. A recirculation duct 55 extends from the flue duct 42 to one or more of the apertures 20, 22 and provides fluid communication between the flue duct 42 and the interior area 14.

Abstract: A high efficiency hot air furnace transfers substantially all of the combustion heat of a clean fuel gas fire to a stream of cool recirculating air by two heat exchangers both of which are mounted in a common plenum through which cool air is recirculated by means of a blower. It differs from the conventional high efficiency furnace in that the secondary heat exchanger is a porous movable heat sink which is alternately exposed to a stream of hot combustion gas and a part of the cool air stream from the recirculating air blower.

Abstract: A furnace apparatus which includes a plurality of water walls. Each includes a plurality of tubes and the water walls collectively enclose a combustion chamber. The apparatus includes a plurality of windboxes, each of the windboxes is disposed intermediate adjacent water walls. A pulverizer and ducting to direct the flow of pulverized coal to the windboxes is also a part of the apparatus in accordance with the invention as is a bisector regenerative air heater having a rotor a housing having a generally cylindrical cavity in which a drum shaped rotor having heat transfer surfaces thereon is mounted for rotation on a shaft. The heater includes ducting for directing flue gas and forced draft air respectively into first and second angular sectors of the cavity which at any one instant will flow over respective angular sectors of the rotor. The rotor is heated during the travel of any portion thereof in the first angular sector and is cooled in the second angular sector.

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 compact apparatus for ultra high energy efficient heating, cooling and dehymidifying of air for use in heating, cooling and heat recovery ventilation of buildings comprises two matrix containers and a fuel combustor for generating useful heat, with the two matrix containers housing stationary matrices of solid materials providing alternately high energy efficient: (a) transfer of energy from combustion products and exhausted air to incoming make up air, (b) indirect evaporative cooling, (c) indirect-direct evaporative cooling (d) dehumidification-indirect evaporative cooling, (e) dehumidification-indirect-direct evaporative cooling.A continuous alternate and conuntercurrent flow of two air streams through the two matrix containers and a continuous flow of the air through the apparatus is maintained by alternately operating air fans controlled by solid state processor.

Abstract: A fuel burning furnace includes a number of energy efficient features. The furnace includes a heat exchanger in which combustion air is preheated by hot discharge gases. Diverters are provided in the heat exchanger to continually urge hot combustion gases toward the interior portions of the heat exchanger to improve its heat transfer characteristics. The furnace incorporates a number of features to determine malfunction and indicate inefficient operation. A humidification control system for the humidification or dehumidification of circulated air also is provided. The furnace also includes a blower motor system which compensates for loss of tension in driving belts and makes correction for blower speed in response to temperature variations.

Abstract: A fuel burning furnace includes a number of energy efficient features. The furnace includes a heat exchanger in which combustion air is preheated by hot discharge gases. Diverters are provided in the heat exchanger to continually urge hot combustion gases toward the interior portions of the heat exchanger to improve its heat transfer characteristics. The furnace incorporates a number of features to determine malfunction and indicate inefficient operation. A humidification control system for the humidification or dehumidification of circulated air also is provided. The furnace also includes a blower motor system which compensates for loss of tension in driving belts and makes correction for blower speed in response to temperature variations.

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: In a far-infrared radiating system, a plurality of radiating units for allowing the combustion gas to pass therethrough are connected in series to form a multi-stage series-connecting construction. The combustion gas releases its heat energy in the form of far-infrared rays when passing through each of the radiating units. The combustion gas having passed through the radiating unit decreases in temperature, and recovers its previous high temperature through combustion of a fuel which is mixed with such combustion gas before the combustion gas enters the following-stage radiating unit. Such combustion is repeated in each of the following stages so that the heat produced by combustion of the fuel is effectively radiated in the form of the far-infrared rays without making waste.

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 total counterflow heat exchanger comprising a system of partitions dividing an interior chamber into a series of channels which coincide with the path of a duct through that interior chamber. A substance at one temperature is passed through the duct, and a substance at a second temperature is passed through the channels, thereby creating a temperature differential gradient over which thermal energy is transfered from one substance to the other as the substances flow through the heat exchanger. The arrangement of the partitions permits a substance to pass back and forth through the channels in the heat exchanger along the same path as the duct, so that while the substance may flow through the heat exchanger at the same net rate as if the partitions were not present, the length of the heat exchange gradient may be increased many times, therefore enhancing the efficiency of the gradient and the heat exchanger.

Abstract: An air preheater wherein heated combustion gas is caused to flow in a straight path through the full lengths of preheater tubes while controlling the velocity and temperature of such gas to sweep liquid droplets from the preheater. The temperature of the preheated air is regulated by mixing inlet air and preheated air to control the temperature of the metal of the preheater at or near the dew point of the combustion gas to thereby inhibit the formation of large liquid droplets which cannot be removed with the gas moving at its velocity through the preheater, whereby essentially all corrosive liquid is removed with the gas to enable the use of carbon steel in the preheater. The air preheater has a bundle of substantially vertical preheater tubes through which combustion gases pass in a substantially straight flow path. The system normally operates with forced draft but a stack disposed integrally with the tubes enables the system to operate with natural draft when the forced draft is not operational.

Abstract: An intake air pathway for a wood-burning stove is provided with a control mechanism which automatically responds both to changes in temperatures for controlling the amount of intake air flowing in the pathway and to pressure due to back puff conditions in the stove for closing the intake pathway with and thereby preventing emissions due to back puff. The point of control of the intake pathway may be placed along different points of the pathway. Control valve and check valve functions may be accomplished with a single control surface (i.e., plate or flap), or alternatively, be segregated into two control surfaces. The control arrangement is disposed such that gravity always acts as a safety feature to close the intake air pathway during an uncontrolled fire (e.g. chimney fire) or physical failure of the control apparatus. A fixed-shield baffle system surrounding a combustor of the stove causes reversals of combustion gasses and a secondary air flow supplied to the combustor.

Abstract: An improved heat pipe comprising a duct having disposed at opposite ends thereof an evaporator with wick-lined hollow fins in the form of extended corrugations thereon, and operable to supply heat to the evaporator comprised of a gas combustor having an internal volume for containing the evaporator and combustion air for supply to a combustion chamber located therein; a wick capable of transporting liquid by capillary action lining substantially all internal surfaces of said heat pipe; an external heat sink operable to remove heat from the condenser; and a heat transport medium contained by said heat pipe. The evaporator is further comprised of a coarse porous material lining and completely filling the spaces within the hollow fins open to the evaporator for increased structural stiffness and ease of fabrication; and a porous mass completely filling the evaporator for increased compressive strength.

Abstract: A maximum efficiency stove or furnace for heating homes or other buildings is disclosed. The furnace includes a combustion chamber supported within a furnace housing by an ash pan. The combustion chamber is spaced apart from the furnace housing to define an air circulation chamber therebetween. A horizontal flue extends through the upper portion of the air circulation chamber, from the rear of the combustion chamber to the front of the top wall of the furnace housing. The ash pan includes a number of heat transfer tubes projecting therethrough to define a grate upon which the fuel is burned and a secondary grate below the heat transfer tubes. The furnace also includes an ambient air preheating chamber attached to the outside surface of the housing. The air to be heated is drawn through the preheating chamber and admitted into the air circulation chamber, whereupon it flows through the heat transfer tubes, around the combustion chamber and flue, and is then exhausted into the room to be heated.

Abstract: A heater for air and liquid utilizing a combustible fuel which includes a first vertical stack including a combustion tube or heat stack with a bottom burner. The heat stack is surrounded by a heat transfer unit with alternate down passages and up passages. The down passages carry the heated exhaust gas. The up passages carry the fluid to be heated. A second vertical stack carries outgoing combustion gases, incoming secondary air supply for combustion, and incoming air to be heated or fluid to be heated. A heat transfer arrangement in the second stack transfers heat from outgoing combustion gases to incoming space air and combustion support air when the unit is used as a space heater.

Abstract: A secondary heat exchanger is positioned within a cold air return plenum of a forced air gas or oil fired furnace to preheat cold air drawn into the furnace through the cold air plenum. A heat recovery flue pipe is connected between a primary flue pipe of the furnace and the secondary heat exchanger, and an exhaust pipe is connected between the secondary heat exchanger and the outside of a structure served by the furnace. A secondary blower coupled to the exhaust pipe draws hot combustion gases from the primary flue pipe through the heat exchanger and exhausts cooled combustion gases to the outside. The secondary heat exchanger comprises a combustion gas inlet plenum and a combustion gas outlet plenum, with a plurality of heat conducting pipes sealingly connected therebetween.

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 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 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: An apparatus is provided for generating heated air, for example, for use in connection with a dryer for particulate material, comprising a base portion having a combustion chamber and a burner for providing a flow of combustion gas. A plurality of open tubes having the first ends communicating with the combustion chamber are provided for receiving the flow of combustion gas. The second ends of the tube extend beyond the base portion. A tubular structure is connected to the base portion surrounding the second ends of the tubes. The tubular structure has partition means for dividing it into a heat exchange chamber adjacent the base portion and surrounding the tubes and a manifold chamber remote from the base portion. The partition cooperates with the tubes to direct the flow of combustion gas into the manifold chamber.

Abstract: A thermal receiver assembly comprising a base member and a support structure affixed to said base member and extending vertically therefrom. The thermal receiver assembly further includes at least one thermal heat collecting assembly which is supported by the base member. The heat collecting assembly comprises a plurality of vertically extending, parallel, spaced-apart conduit members having inlet and outlet ends. The inlet ends terminate in an inlet manifold for receiving a coolant, and the outlet ends terminate in an outlet manifold for removal of heated coolant. The heat collecting assembly further includes a plurality of substantially horizontally extending and vertically flexible attachment members having an end affixed to the support structure and another end affixed to individual conduit members to permit vertical movement of individual conduit members while restraining said conduit members from any substantial horizontal movement.

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: Combustion gas recirculating system for a gas-fired furnace of the type which includes a plenum with a cold air inlet duct and a warm air exhaust duct, a combustion chamber where gas is burned to form hot combustion gases, a heat exchanger in the plenum for receiving the hot combustion gases and including an outer surface configuration past which air can flow and be heated, an outlet in the heat exchanger for the hot combustion gases, and a blower for moving air through the plenum and past the heat exchanger. A recirculation duct connects the combustion gas outlet with the cold air inlet duct and a thermostatically controlled valve regulates the flow of hot combustion gases from the combustion gas outlet to the cold air inlet duct by opening when the hot combustion gases reach a predetermined temperature and closing when the hot combustion gases are below said predetermined temperature.

Abstract: A hot air furnace has an outer housing and a firebox positioned within the housing. A space between the outer housing and the firebox defines a pre-heating chamber which communicates through an air distribution blower to a lower chamber and an upper chamber within the housing. The walls of the firebox are hollow and open into the lower chamber and the upper chamber so that air extracted by the distribution blower from the pre-heating chamber and directed into the lower chamber is heated as it is channeled up through the hollow walls of the firebox prior to entering the upper chamber. A smoke chamber is located within the upper chamber and it serves to further heat the air entering the upper chamber. A combustion air blower is provided and it together with the distribution blower is automatically controlled by a thermostat located within the space to be heated.

Abstract: Improved furnaces are described in which secondary and tertiary heat exchanges are incorporated into new and existing hot-air furnace systems for controlled cooling of hot combustion products by co-current and countercurrent heat exchanges. Hot combustion products are cooled to a temperature at which latent heat of water vapor contained in combustion gases are substantially recovered.In one embodiment of our invention, a secondary heat exchanger comprises inter alia a closed hollow annular drum concentric with and spaced from a cylindrical combustion chamber, said annular drum having an upper annulus preferably filled with randomly packed refractory material.A second embodiment of our invention comprises a closed double-annuli drum heat exchanger concentric with and spaced from a cylindrical combustion chamber.Finned tube or thermosiphon heat exchangers can be arranged sequentially with the primary heat exchanger combustion chamber to function as a secondary heat exchanger or as a tertiary heat exchanger.

Abstract: A solar power plant with a gas turbine circuit, having a compressor, a solar heater, a combustion chamber for heating air compressed in the compressor, a turbine and a generator, the solar heater and the combustion chamber being connected between the compressor and the turbine, and a valve for connecting and disconnecting the solar heater to the circuit, the combustion chamber having double walls defining an outer space between the walls and an inner space, the outer space of the combustion chamber being connected in series with the solar heater upstream thereof, in flow direction of the compressed air, the inner space of the combustion chamber being connected downstream of the solar heater in flow direction of the compressed air, and the valve connecting the outer space and the inner space of the combustion chamber to each other.

Abstract: An improved heat exchanger (74) for use with a heating furnace (72) is disclosed. The exchanger (74) includes a first plurality of tubes (84) which conduct hot exhaust gases from the furnace (72). Tubes (98) carrying outside air for combustion in the furnace (72) pass proximate the first group of tubes (84) within a heat exchange chamber (90) wherein heat is transferred to the combustion air via a heat transfer medium. Similarly, ambient air in the building passes through the heat exchange chamber (90) of the exchanger (74) through a third plurality of tubes (118). These tubes (118) also pass proximate the tubes (84) carrying hot exhaust gases. In a preferred embodiment, a conduit (80), through which the exhaust gases transit from the furnace (72) to the first plurality of tubes (84) in the heat exchanger (74), can be routed through plenums (110, 126) through which combustion air and ambient air circulate after exiting the second and third pluralities of tubes (98, 118).

Abstract: A system for recovering the waste heat normally exhausted into the atmosphere by chemical or other processing plants. The invented system comprises a substantially self-contained apparatus for receiving hot exhaust gases and extracting the waste heat therefrom for some beneficial use, such as pre-heating inlet air in an inlet plenum. The system may include temperature and pressure controls which enhance the safety and efficiency of the system's operation, and further may include flow controls in a multiple burner installation so that the desired fuel air ratios and heat distribution may be achieved. By building the present invention as a substantially self-contained and self-supporting assembly, on site installation time and the required alteration of pre-existing on site equipment may be minimized, thereby affecting substantial economic savings by minimizing the resulting down time of the processing plant.

Abstract: A waste heat recovery device particularly usable for heating the air traveling through a cold air return duct to a hot air gas heating furnace which includes an exhaust box securable to the wall of the furnace and adapted to receive exhaust gases therein to gather heat in the plenum chamber defined by the exhaust box, the exhaust box also including an exhaust gas outlet to expel gases to the existing heater stack or flue for venting, the plenum chamber including an exhaust coil being in fluid flow communication through a conduit to a return coil which is located within the cold air return, the conduit means being partially filled with a thermal transfer fluid such as water which will boil within the conduit in the exhaust coil means and will condense within the conduit in the return coil means and as such will effect rapid thermal transfer from the heated exhaust waste to the incoming cold air traveling through the cold air return and thereby achieve waste heat recovery.

Abstract: A system for recovering the waste heat normally exhausted into the atmosphere by chemical or other processing plants. The invented system comprises a substantially self-contained apparatus for receiving hot exhaust gases and extracting the waste heat therefrom for some beneficial use, such as pre-heating inlet air in an inlet plenum. The system may include temperature and pressure controls which enhance the safety and efficiency of the system's operation, and further may include flow controls in a multiple burner installation so that the desired fuel air ratios and heat distribution may be achieved. By building the present invention as a substantially self-contained and self-supporting assembly, on site installation time and the required alteration of pre-existing on site equipment may be minimized, thereby affecting substantial economic savings by minimizing the resulting down time of the processing plant.

Abstract: A self-cleaning heat exchanger in combination with a home furnace system which draws combustion air from outside the home is disclosed. Gases of combustion are drawn up through a plurality of vertical tubes and out a chimney by a fan mounted in the chimney. The lower portions of the tubes are cooled by inside air drawn over them by the return air blower of the furnace, the upper portions of the tubes are cooled by cold outside air drawn across them by the furnace burner unit. Moisture which condenses in the upper portions of the tubes is drawn down through them by gravity. The higher temperature in the lower part of the tubes causes this condensate to revaporize and rise to the upper portion of the tubes, where the process repeats itself. As more water vapor enters the tubes in the flue gas, distilled condensate eventually drops out of the tubes and runs into a drain at the lower end of the heat exchanger.

Abstract: In connection with a furnace having a forced air recirculation system driven by a blower, and an atmospheric flue for its combustion chamber, a heat exchanger housing surrounding the flue to extract heat therefrom, the furnace blower drawing atmospheric air through the heat exchanger housing into the recirculating air system in proportions controlled either manually or automatically.

Abstract: This invention provides a method and apparatus for transferring heat to a cooler gas from a hotter gas which contains tri-atomic molecules with good infra-red energy absorption characteristics, for example CO.sub.2. The hotter gas is passed in a first direction along a conduit, and simultaneously the cooler gas is jetted through and across the hotter gas in a direction transverse to the hotter gas direction. This allows the tri-atomic molecules minimally entrained in the cooler gas jets to provide heat to the cooler gas firstly through transferring their initial kinetic energy to the cooler gas molecules by way of collision, and secondly by absorbing infra-red energy radiated from the hotter gas and passing this absorbed energy to the cooler gas molecules also through collision.

Abstract: The flue pipe for a combustion chamber of a hot air furnace passes through the hot air plenum and then passes through the cold air supply duct. Heat exchange fins are secured to a length of the flue pipe located within the hot air plenum and within the cold air supply duct to utilize the residual heat of the flue gases to heat the air flowing around the fins. The flue pipe extends to a chimney for exhausting the gases. A sensor is located for response to the temperature of the air heated by both the flue pipe passing through the hot air distribution header and the furnace itself for energizing a driven blower. A thermostat produces a command signal to deliver fuel to the furnace burners. The blower is energized when the temperature in the hot air plenum reaches a predetermined level.

Abstract: A system for recovering the waste heat normally exhausted into the atmosphere by chemical or other processing plants. The invented system comprises a substantially self-contained apparatus for receiving hot exhaust gases and extracting the waste heat therefrom for some beneficial use, such as pre-heating inlet air in an inlet plenum. The system may include temperature and pressure controls which enhance the safety and efficiency of the system's operation, and further may include flow controls in a multiple burner installation so that the desired fuel air ratios and heat distribution may be achieved. By building the present invention as a substantially self-contained and self-supporting assembly, on site installation time and the required alternation of pre-existing on site equipment may be minimized, thereby affecting substantial economic savings by minimizing the resulting down time of the processing plant.