Abstract: An improved boiler for generating steam includes a housing that has a proximal end and a distal end, with a water-entry port at the proximal end. A plurality of firetubes are disposed lengthwise in the housing, and the firetubes extend substantially the length of the housing between the proximal end and the distal end. The firetubes are used to pass the heated flue gas through the housing. A pair of side baffles are affixed to the inner surface of the housing that extend at least partially down the length of the housing to separate a portion of the last pass of firetubes near the housing from the remaining firetubes in the housing. At least two cross-sectional baffles are positioned adjacent the side baffles to direct the flow of water opposite to the flue gas flow in the separated part of firetubes.

Abstract: Two improvements for heaters are disclosed which can be implemented as either apparatus or method. First is a novel flue gas injection system. Second is a novel burner configuration. The improvements can be used alone or together. In the flue gas injection system, flue gas is injected between the burners and the tubes to reduce heat flux on the tubes and shift part of the heat duty from the radiant to the convective section. These approaches work toward increasing the capacity of heaters where we can increase the firing rate in the heater and still keep the tube metal temperature and radiant fluxes within acceptable limits.

Abstract: A firetube boiler furnace having two combustion sections and an in-line intermediate tubular heat transfer section between the two combustion sections and integral to the pressure vessel. This design provides a staged oxidant combustion apparatus with separate in-line combustion chambers for fuel-rich primary combustion and fuel-lean secondary combustion and sufficient cooling of the combustion products from the primary combustion such that when the secondary combustion oxidant is added in the secondary combustion stage, the NOx formation is less than 5 ppmv at 3% O2.

Abstract: A boiler having a first pass furnace and a set of second pass tubes, a reversing recess proximate to the furnace and tubes for reversing the flow of gases between the furnace and tubes, and a rear access door providing access to the recess, in which there is an integral, self-sustaining reversing chamber sized and configured to fit within and be removably held within recess. The chamber is enclosed by walls on all sides thereof except the side facing the recess which is open and concave. The chamber is formed of loosely-packed ceramic fibers with air entrapped between said fibers to provide greater insulation.

Abstract: An improved compact water heater is provided for use in recreational vehicles and the like, wherein the water heater is designed for facilitated assembly and for increased heat transfer capacity to achieve reduced heater recovery time. The water heater comprises a compact tank with appropriate cold water supply and hot water outlet fittings. A combustor unit is mounted within the tank, wherein the combustor unit is defined by interconnected matched shell-shaped combustor sections cooperating to provide a generally U-shaped combustor flow path with extended heat transfer surface area for improved water heater performance with reduced recovery time.

Abstract: A boiler which is designed to be fired by oil and/or gas comprises a water cooled combustion tube closed at one end and located within a water space of the boiler, is connected to a solid fuel fired boiler by an auxiliary furnace having a combustion chamber with means to introduce solid fuel into the combustion chamber, and an opening in the wall of the combustion chamber, the opening having an extension nozzle extending therefrom whereby hot gases may pass from the extension nozzle of the furnace into the combustion tube of the boiler at a position intermediate the ends of the combustion tube.

Abstract: This invention relates to boilers more particularly to shell boilers and improvements in their operation.In more detail this specification describes and claims a boiler comprising a housing, an inlet for leading a fuel or a fuel/gas mixture into a combustion chamber, at least one array of pipes in series with the combustion chamber, an exit for leading exhaust gases away from the boiler and means for cooling the pipes and the combustion chamber, characterized in that the boiler includes a catalyst disposed in such a position that at least a proportion of any unburnt fuel leaving the combustion chamber undergoes catalytic combustion.

Abstract: The present invention relates to wet type water box boiler having five smoke-flues characterized by that the hot gas produced by the combustion is subject to twice of heat exchange with the water box in its route, thereby allowing an operating temperature of 1900.degree. C. and enhancing the heat efficiency to 95%.

Abstract: A boiler having a firebox in which combustion of fuel fed thereto is initiated, a flame tube leading from the firebox in which combustion of fuel may continue and an array of smoke tubes through which the products of combustion issuing from the flame tube are fed to a chimney. The surfaces of the firebox, flame tube and smoke tubes are surrounded by a chamber containing a heat transfer medium, peferably water. A superheater in which steam generated in the chamber is superheated may be included. The superheater is preferably located at the end of the flame tube.