Fluid fuel burners

Claim 1

A fluid fuel burner for providing a high velocity stream of hot gas to be used for heating the interior and structure of large enclosures such as furnaces, comprising a convergent casing defining a combustion chamber, means to supply air and means to supply fluid fuel to one end of the combustion chamber, an outwardly flared outlet nozzle coaxial with said combustion chamber and at the smaller end of the combustion chamber through which the products of combustion within the combustion chamber emerge from the burner as a high velocity stream of hot gas, and means which coact with the products of combustion which emerge from the combustion chamber through the outlet nozzle so that those products of combustion emerge from the burner as a divergent stream of hot gas, wherein the improvement comprises said means which coact with the products of combustion which emerge from the combustion chamber through the outlet nozzle including a compressed air supply tube which is adapted for connection to a source of compressed air outside the burner, the compressed air supply tube extending through the combustion chamber and the outlet nozzle, and terminating, at a point beyond the end of the outlet nozzle remote from the combustion chamber, in a compressed air outlet orifice, and compressed air deflecting means arranged to direct, radially of the axis of the compressed air supply tube, compressed air which emerges from the compressed air outlet orifice so that the radially directed compressed air acts upon the products of combustion which emerge from the outlet nozzle, so as to form said divergent stream of hot gas.