Abstract: A method for converting a gas boiler into a liquid-fuel boiler. The gas boiler comprises an enclosure which accommodates a firebox, which forms a combustion chamber and is provided with a supporting wall which supports a burner provided with a combustion head, which protrudes from the supporting wall and has a substantially cylindrical shape with an internal cavity formed axially; the enclosure is provided with a passage in which an atomizing nozzle, connected to a liquid fuel supply duct, and at least one ignition electrode are inserted from the outside; a snorkel-shaped body is also applied to the end of the combustion head that is opposite with respect to the supporting wall and the supply duct is connected supply duct is connected to a pressurized source of liquid fuel.

Abstract: A boiler for producing hot water or steam, comprising a containment enclosure, which forms a heating chamber that contains water to be heated, and accommodating a firebox body, which forms internally a combustion chamber with a burner associated therewith which has a combustion head, accommodated in the combustion chamber, and a device for premixing air and gas which is connected to the combustion head. According to the invention, the premixing device comprises an air supply duct, which is connected to the combustion head, and a mixing tubular body, which is extended coaxially to the supply duct in order to create, between the internal lateral wall of the supply duct and the external surface of the sidewall of the mixing tubular body, an intake region which has a transverse air passage section that is narrower than the air passage section formed by the supply duct upstream of the mixing tubular body, along the air flow direction.

Abstract: A boiler comprising an enclosure which forms a heating chamber which contains water to be heated and accommodates a firebox which forms a combustion chamber with a burner associated therewith which comprises a combustion head, arranged in the combustion chamber and connected to a supply duct, and provided with a premixer of combustion air and combustible gas which is interposed along the supply duct. The combustion chamber is connected to a stack for the evacuation of the combustion gases into the external environment, elements being further provided for generating a flow of a mixture of air and gas toward the combustion head; at least one duct being provided for conveying the combustion gases which connects the stack to the supply duct.

Abstract: A condensing boiler, which comprises an outer enclosure, which defines a chamber for containing water to be heated and accommodates a combustion chamber which is connected to a plurality of heat exchange tubes which lead into a fume collection chamber which is connected to a fume evacuation stack; a condensing device for the fumes is arranged in the fume collection chamber; the stack has an intake which is arranged substantially coaxially to the fume collection chamber and the condensing device comprises at least one fume cooling element which has a substantially annular shape and is arranged substantially coaxially to the fume collection chamber.