Abstract: A water heater apparatus is shown which includes a water heating tank having generally cylindrical sidewalls with upper and lower ends, each of which is closed by a transverse wall section to define a closed tank interior. The tank also has a water inlet and a water outlet. A plurality of vertically arranged fire tubes are connected between the upper and lower transverse wall sections, each fire tube having an open interior for conducting products of combustion. A combustion chamber is mounted on the upper end of the water heating tank for providing products of combustion to the open interiors of the fire tubes. A flue collector chamber is located at the bottom end of the tank for collecting and exhausting the products of combustion from the vertically arranged fire tubes. An induction blower draws the products of combustion downwardly from the combustion chamber, through the fire tubes and out the flue collector chamber for exhaustion from the apparatus.

Abstract: A water heater apparatus is shown which includes a water heating tank having generally cylindrical sidewalls with upper and lower ends, each of which is closed by a transverse wall section to define a closed tank interior. The tank also has a water inlet and a water outlet. A plurality of vertically arranged fire tubes are connected between the upper and lower transverse wall sections, each fire tube having an open interior for conducting products of combustion. A combustion chamber is mounted on the upper end of the water heating tank for providing products of combustion to the open interiors of the fire tubes. A flue collector is located at the bottom end of the tank for collecting and exhausting the products of combustion from the vertically arranged fire tubes. An induction blower draws the products of combustion downwardly from the combustion chamber, through the fire tubes and out the flue collector for exhaustion from the apparatus.

Abstract: The invention relates to a water heating apparatus which uses a submergible, pressurized combustion chamber having multiple external heating surfaces, a forced draft burner and a flue collector that collects and passively recirculates a portion of the flue gases back into the burner air intake region. An improved burner array more completely mixes the combustible gases in the combustion region and operates over a wide range of input demands.

Abstract: In a fluid heating apparatus having a fluid tank, a combustion chamber communicating with the fluid tank for heat exchange, and a combustible fluid delivery system coupled to the combustion chamber, a plurality of valves are individually configured in either an off-state or an on-state for delivering combustible fluid to the combustion chamber. Depending on the configuration of the multiple valves, the rate at which combustible fluid is supplied to the combustion chamber may be varied in response to a heat demand signal. Individual valve signals are generated for each of the multiple valves in response to the heat demand signal to place the multiple valves in a configuration to supply combustible fluid at predetermined rates. The demand signal is calculated in response to reading temperature at an inlet temperature probe and an outlet temperature probe, wherein the outlet temperature probe is located nearer a fluid outlet from the fluid tank than is the inlet temperature probe.

Abstract: A water heater/boiler design is shown having a tank with a submergible, pressurized combustion chamber and a resilient sealing means which divides the interior of the water heater tank into a primary and secondary heat exchange compartments. A forced draft burner is used to heat the combustion chamber with the products of combustion passing through multiple heat exchange surfaces to a flue collector located on the exterior of the device.

Abstract: The invention relates to a water heating apparatus and method to passively recirculate flue gas in order to reduce NO.sub.x emissions formed during combustion. The apparatus uses a high efficiency burner, a submergible, pressurized, combustion chamber having multiple external heating surfaces, and a flue collector that collects and passively recirculates a portion of the flue gases back into the burner air intake while exhausting the rest. The multiple external heating surfaces are installed within a closed tank and are submerged in water under pressure during use.

Abstract: A direct contact water heater is provided having an upright, closed cylindrical tank formed from an outer tank shell. The outer tank shell has a top, a bottom and an external sidewall extending between the top and bottom to define an interior of the tank. A combustion chamber is centrally located within the interior of the tank. Combustible fuel is introduced downward from a combustion means into the combustion chamber and is ignited in the presence of air within the combustion chamber to create products of combustion. A plurality of spray nozzles are connected to a water supply to be heated. The spray nozzles are evenly spaced around and along the length of the combustion chamber for directing water from the water supply into the combustion chamber so that more uniform contact of the water is achieved with the products of combustion to facilitate heating of the water.

Abstract: A water heater is shown having a closed tank with an opening for receiving a combustion chamber, the interior of the tank normally containing water under pressure. A combustion chamber is located within the tank interior and includes a body portion having an open end adjacent the tank opening into which combustible fuel is introduced and ignited in the presence of air to create products of combustion. A flue collector is mounted on the exterior of the closed tank and has an annular chamber surrounding a flue opening for receiving the products of combustion for exhaustion to the atmosphere. An outer wall portion closes one end of the flue opening to provide a closed compartment within the collector which can be pressurized by an external blower. An inner wall portion of the collector has an opening which communicates with the combustion chamber.

Abstract: A system and method for controlling operation of a water heater provides generating a heating demand signal which a minimum level corresponds to a required heat input for maintaining water temperature in the water tank in case of no exogenous demand for water. Responsive to the heating demand signal, air flow from the forced draft blower and flow of combustible fluid from the combustible fluid delivery system are varied to produce combustion product over a minimum 15 to 1 ratio. This allows water heating to be varied to meet maximum expected exogenous demand or to maintain water temperature with no exogenous demand.

Abstract: A combustion system is shown having a combustion chamber into which fuel is introduced and ignited in the presence of air to create products of combustion which are routed through an exhaust vent. A forced draft burner intakes air and fuel and ignites these components to supply heat to the combustion chamber. A valve is provided within the exhaust vent for varying the degree of restriction within the exhaust vent. A modulation drive motor is connected to the variable restriction in the exhaust vent and to the air and fuel supply sources for increasing the exhaust vent back pressure as the ratio of air and fuel being supplied to the combustion chamber are decreased.

Abstract: An improved water heater is shown which includes a water heating tank having external cylindrical sidewalls, an interior, and initially open upper and lower ends. A combustion chamber is connectable to the water heating tank and houses a burner for the combustion of a selected fossil fuel. A fire tube unit of a fixed length is received within the interior of the water heater tank and has an upper transverse wall section, a lower transverse wall section and interconnecting fire tubes. The fire tubes have open interiors which receive the products of combustion from the combustion chamber for heating water contained in the water heating tank. Flanges and resilient seals are located at the upper and lower ends of the water heating tank for securing the fire tube unit within the interior thereof.

Abstract: A potable, hot water storage vessel is shown with a metallic body having a water inlet, water outlet and at least one additional opening communicating the vessel interior and exterior. A flexible, non-molded liner is installed within the vessel interior through the additional opening. The liner has integrally formed ports which extend through the vessel inlet and outlets to the exterior of the vessel body. A bolt-on flange is received on the vessel exterior at the inlet and outlet to form a seal with each of the liner ports.

Abstract: A bolt-on fitting is shown for coupling a fitting to an object having external sidewalls and a normally closed interior containing a liquid, such as a water heater tank or boiler. The bolt-on fitting has a body with an inner surface and an outer surface. A plurality of bolt openings are spaced about the periphery of the body. An O-ring is located on the inner surface for sealing between the flange and the mating surface on the tank. The inner surface of the flange is concave, being curved about both a horizontal and a vertical axis drawn to bisect the body so that the bolt openings form isolated points of contact with the tank surface when the flange is bolted into position.

Abstract: A water heater/boiler design is shown having a tank with a submergible, pressurized combustion chamber so that all of the heating surfaces of the combustion chamber are submerged under water. The products of combustion are routed from the submerged combustion chamber to a secondary heat exchanger having heat exchange tubes which are also submerged in the tank. A forced draft burner is used to heat the combustion chamber and the burner inlet air is preheated by passing the inlet air over portions of the secondary heat exchanger located on the exterior of the tank.

Abstract: An improved water heater or boiler having a water heater tank, a combustion chamber and a burner wherein a selected insulating material separates the combustion chamber and the tubesheet of the water heater tank to maintain the temperature of the tubesheet below the ductile to brittle transition temperature.

Abstract: A modular fluid storage and heating system is provided which includes a plurality of different, interconnectable tank components of standardized dimensions such as fluid storage tanks, closure caps, and heater assemblies. Each of the tank components is sufficiently compact in size to pass through standard-sized corridors and doorways to permit assembly on site of a fluid storage and heating system configured specifically to the needs of a particular user. Because each of the tank components is of a standard size, fluid storage and heating systems may be constructed from standard-sized rather than from custom-sized components, thereby reducing considerably the expense and time associated with construction of such systems.

Abstract: A water heater is shown which has a water tank having a water inlet, a water outlet, and an opening in a sidewall of the tank. A combustion chamber assembly has a submergible portion which is adapted to be received within the opening in the tank sidewall. The combustion chamber assembly has a mounting flange for detachably engaging a tank mounting flange for mounting the assembly within the tank. The combustion chamber assembly has a plurality of curved fire tubes. Each of the tubes has at least one end which communicates through the mounting flange with the tank exterior. The combustion chamber assembly is removable from the tank by detaching the mounting flanges and sliding the assembly out of the tank opening.

Abstract: A heat exchanger has a modular construction to create uniformity among several of its components. The heat exchanger utilizes concentric tubes, with one fluid flowing through the inner tube, and the other fluid flowing through the annular space in the outer tube. The inner tube fluid flows back over the outer tube, further exchanging heat, as it is discharged. The heat exchanger includes four cup-shaped modules that nest or slide together. Each module includes a sleeve with a port for one of the fluids. Each module also has a convex portion that slides sealingly into an adjacent module and contains holes for the tubes. The tubes are sealed into the holes in the convex portions, causing each module to define one of the four manifolds necessary for the operation of the heat exchanger.

Abstract: A heat exchanger for heating liquids with other liquids or vapors. An inner flow tube is carried concentrically within an outer flow tube to define an inner passage and also an annular passage. A first manifold directs all of the incoming fluid from one fluid source to either the inner or annular passage. A second manifold directs all of the incoming cooler fluid from the other fluid source to the other passage. A third manifold at the other end of the outer tube discharges the fluid from it so that it does not mix with the inner tube fluid. The outer tube is immersed in inner tube fluid to cause heat transfer through the walls of the inner tube and outer tube.