Patent ID: 8001773

Claim:
Apparatus for producing hot gas comprising: a) a first elongated combustion chamber having an open end and a closed end, b) a second elongated combustion chamber surrounding the first combustion chamber and mounted with respect thereto to define an annular space between them, the second combustion chamber having an open end juxtaposed to and longitudinally spaced from the closed end of said first combustion chamber and a closed end juxtaposed to and longitudinally spaced from the open end of said first combustion chamber, c) a fuel inlet protruding through the second combustion chamber and opening into the first combustion chamber adjacent its closed end, said fuel inlet including a mixing area and an ignition device, d) an air inlet for combustion air leading into the space at the closed end of said second combustion chamber defined between the closed end of the second combustion chamber and the open end of the first combustion chamber and directed to produce a spiral swirl of combustion air through the annular space defined between the first and second combustion chambers, e) a bypass leading from an upstream point of the air inlet to the fuel inlet, f) a high surface area element mounted on the inner periphery of the first combustion chamber between the fuel inlet opening and the open end of the first combustion chamber for capturing fuel droplets occurring on account of Leydenfrost effect in the first combustion chamber and combusting them under oxygen-deficient conditions, wherein the first combustion chamber being designed for mixing fuel and bypass air and producing oxygen deficient vaporization thereof and producing a first flow of combustion gases in a first longitudinal direction from the closed end of the first combustion chamber, past the high surface area element, toward the open end of the first combustion chamber, whereupon combustion gas exiting from the open end of the first combustion chamber is merged with combustion air entering the space at the closed end of said second combustion chamber defined between the closed end of the second combustion chamber and the open end of the first combustion chamber and carried in a second longitudinal direction counter to the first direction, via spiral swirling, through the annular space between the first and second combustion chambers to the open end of the second combustion chamber where it exits as an oxygen-rich fully combusted hot gas.