A steam boiler or analogous heat exchanger is provided with a gas-fired burner comprising a plenum chamber from which a combustible gas-air mixture escapes through an inexpensive and readily replaceable burner member formed of foraminous ceramic material. The porosity and thermal conductivity of the burner member are such as to produce substantially flameless combustion toward the outer surface of the burner member, which causes that surface to incandesce and to radiate heat directly to water-filled boiler elements facing the burner member.
A vapor generator for vaporizing a liquid by burning a combustible mixture which has low pollutant emissions. A porous burner having a cooling liquid tube within it divides the interior of a housing into a combustion chamber and a plenum into which the combustible mixture is blown. The vaporized mixture passes through the wall and burns on its outer surface. In a coiled tube surrounding the porous burner the liquid from the cooling liquid tube is vaporized.
A compact combustor-boiler construction is described that during operation will emit substantially no nitrogen oxides, while burning a fuel/air mixture essentially to completion. Nested cooled porous plug burners with a common fuel/air supply chamber are flanked by inner and outer burned gas cooler units with the coolant flow paths through the burners being connected in series with a flow path through the outer and inner cooler units in sequence whereby the coolant (working fluid) is sequentially exposed to liquid heating, nucleate boiling, film boiling and, preferably, super-heating.
A boiler or vapor generator using catalytic combustion of hydrocarbons to evaporate a fluid passed through pipes operates in accordance with the principles of U.S. Pat. Nos. 3,908,602 and 3,952,707 and comprises vertically disposed catalyst elements within a thermally insulated housing. The space between the catalyst elements, which face one another, is occupied by a pair of coiled tubes which are superposed so as to be imbricated in one another. The tube coils shield the catalyst elements from radiation interchange of heat. The two coiled tubes are connected with a lower supply tube and an upper collector and are traversed by the liquid to be vaporized and heated so as to form a wall without interstices between the catalyst panels.
A monotube steam generator, the pressure element or elements of which are comprised of tube of partially flattened section, enclosed within mainly close fitting substantially solid metal encasements with generally flat surfaces.
An improved compact heating system, particularly adapted for heating water and generating steam, includes a combustible gas supply zone, a combustion chamber therearound in the form of a hollow burner element having a plurality of radial channels in heat exchange relation with an array of heat exchange elements spaced peripheral therefrom, and gas ignition means. The channels are preferably of special configuration to improve heat transfer efficiency. The system is adapted to efficiently burn a high velocity stream of combustible gases and develop a wide range of B.T.U. outputs per hour, including multi-million B.T.U. output, while retaining advantages of larger types of heating systems. Improved baffles for heat exchanger elements are also provided.
