Abstract: A heat exchanger for use with a furnace, each heat exchanger includes a plurality of heat exchanger elements. Each heat exchanger element includes a pair of clamshells sealingly attached to one another. The heat exchanger element includes a longitudinal axis. A pair of depressions are disposed in each respective said pair of clamshells. The depressions face one another to form a passageway wall and a serpentine fluid passageway therebetween. At least a portion of the serpentine fluid passageway extends along the longitudinal axis. A plurality of enhancements are formed in the depressions and are disposed within the portion of the serpentine fluid passageway. The plurality of enhancements project into the serpentine fluid passageway. Each enhancement constitutes a corrugation having a substantially trapezoidal longitudinal cross-section. A longitudinally positioned passageway wall portion is extended between each adjacently positioned enhancements within each clamshell.

Abstract: A heat exchanger for use with a furnace, each heat exchanger includes a plurality of heat exchanger elements. Each heat exchanger element includes a pair of clamshells sealingly attached to one another. The heat exchanger element includes a longitudinal axis. A pair of depressions are disposed in each respective said pair of clamshells. The depressions face one another to form a passageway wall and a serpentine fluid passageway therebetween. At least a portion of the serpentine fluid passageway extends along the longitudinal axis. A plurality of enhancements are formed in the depressions and are disposed within the portion of the serpentine fluid passageway. The plurality of enhancements project into the serpentine fluid passageway. Each enhancement constitutes a corrugation having a substantially trapezoidal longitudinal cross-section. A longitudinally positioned passageway wall portion is extended between each adjacently positioned enhancements within each clamshell.

Abstract: An induced draft, fuel-fired furnace having a heat exchanger with an inlet and an outlet includes a vent having an inlet, a burner, and a vented vestibule in fluid communication with the vent. A blower has an inlet in fluid communication with the heat exchanger outlet, and an outlet disposed at the inlet of the vent. The blower outlet has a cross-sectional area smaller than the vent inlet. The vent inlet and blower outlet define a vent inlet opening. A drafthood formed with an inlet is disposed in the vestibule and forms a plenum in fluid communication with the vent inlet opening. A source of combustion products is disposed in the furnace such that combustion products produced thereby are in fluid communication with the drafthood inlet and vent inlet opening. The source of combustion products includes either a standing pilot or electronic ignitor for igniting fuel operably discharged from the burner.

Abstract: The present invention is an improved serpentine heat exchanger. Two metal sheets are crimped together, sealed at their abutting edges. The sheets have matching depressions which from a serpentine air passageway. Within the passageway are elongated ribs and column like dimples which serve as obstruction to the air flow, directing fluid flow over under-utilized portions of the passageway and generating turbulent fluid flow near heat transfer surfaces.

Abstract: Heat transfer structure for transferring heat from products of combustion to air to be conditioned in a furnace. The heat transfer structure includes an inlet portion receiving hot products of combustion from a burner and extending generally transversely to the direction of the flow of air to be conditioned by heat transfer association therewith. The heat transfer structure further includes at least three successive legs extending generally parallel to the direction of air flow. In one form, the transverse leg is disposed at the inlet portion of the air flow passages, and in a modified form, the transverse leg is disposed remotely therefrom. In the illustrated embodiments, the air moving structure is disposed in a lowermost portion of the cabinet, with the transverse inlet leg of the heat exchanger being selectively disposed lowermost or uppermost to define the two selective arrangements.

Abstract: In the operation of a heat pipe furnace having a plurality of heat pipes and means for conducting a heated fluid in sequential heat transfer association with the heat pipes, an apparatus and method of detecting a malfunction of any one of the heat pipes of said plurality comprising means for and the steps of monitoring the temperature of the most sequentially downstream heat pipe of the plurality of heat pipes and determining whether said monitored temperature is within a preselected range of temperatures.

Abstract: A metal insert is provided for reducing NO.sub.x emissions in a gas burner which comprises an inverted channel member having support legs movably retained in at least one of the burner ports to allow for movement caused by thermal expansion and contraction of the channel member. The channel member has downwardly extending leg portions positioned adjacent a high temperature zone of the gas flame and within a low temperature zone of the flame.

Abstract: A heat pipe heat transfer structure for use in a furnace wherein individual heat pipes are arranged in a series for successive heat transfer association with the hot products of combustion of the furnace. The heat transfer enclosure defines successively a combustion chamber portion, an acoustic decoupling portion, and an input heat transfer chamber portion. The heat transfer chamber portion, in turn, is divided into first and second portions. The first portion of the input heat transfer chamber portion, in the illustrated embodiment, decreases in cross sectional area in a direction away from the burner. The final portion of the input heat transfer chamber portion, in the illustrated embodiment, has a constant cross sectional area.

Abstract: An improved condensate neutralizer for use in a high efficiency furnace utilizing hydrocarbon gaseous fuel wherein acidic liquid condensate forms. The neutralizer is provided with a bypass for conducting the condensate from the furnace directly to a drain without passing through the neutralizer in the event condensate flow through the neutralizer becomes substantially impeded. Also disclosed is structure for indicating substantial impediment of flow of the condensate through the neutralizer for alerting the user to the need of servicing of the neutralizer. A separator/trap is provided for transferring the condensate from the furnace selectively to the neutralizer or bypass.

Abstract: A domestic forced-air furnace provided with a condensate collector downstream of air moving structure for flowing the products of combustion through the furnace. The furnace includes a secondary heat exchanger. Condensate produced therein is transferred therefrom through the air moving structure to the condensate separator. The secondary heat exchanger and air moving structure are inclined slightly to the horizontal so as to cause continuous flow of condensate therethrough not only during operation of the furnace but also subsequent thereto to assure removal of condensate from the furnace components and thereby avoid corrosive damage thereto from the condensate. The secondary heat exchanger provides the primary pressure drop in the combustion product flow path, permitting control of the furnace capacity by simple modification thereof without the need for changing other components, such as the air moving structure.

Abstract: A high efficiency domestic furnace incorporates means for separating and neutralizing flue gas condensate. Acidic condensate from the flue gas products of combustion is neutralized by contact with neutralizing material in a housing through which the condensate is flowed. The use of the neutralizer in connection with a high efficiency domestic furnace permits discharge of the condensate directly to the household drain. The neutralizer is arranged to be self-flushing and defines a serpentine, series flow path and is arranged to discharge the neutralized condensate as a result of the entry of additional acidic condensate at its inlet.

Abstract: An induced draft, fuel-fired furnace having a heat exchanger with an inlet and an outlet includes a vent having an inlet, a burner, and a vented vestibule in fluid communication with the vent. A blower has an inlet in fluid communication with the heat exchanger outlet, and an outlet disposed at the inlet of the vent. The blower outlet has a cross-sectional area smaller than the vent inlet. The vent inlet and blower outlet define a vent inlet opening. A drafthood formed with an inlet is disposed in the vestibule and forms a plenum in fluid communication with the vent inlet opening. A source of combustion products is disposed in the furnace such that combustion products produced thereby are in fluid communication with the drafthood inlet and vent inlet opening. The source of combustion products includes either a standing pilot or electronic ignitor for igniting fuel operably discharged from the burner.