Abstract: This combined microwave and optic rotary joint has a fixed part and a rotating part in rotation about an axis .DELTA. in relation to the fixed part. It has at least one pair of microwave guide inputs, one of which is positioned in the fixed part while the other is positioned in the rotating part, these microwave guide inputs being coupled to each other by a coaxial link that is fixedly joined to the rotating part and placed in a conduit going through the fixed and rotating parts along the rotation axis .DELTA.. The core of the coaxial link is drilled with a longitudinal channel enabling the passage of an optic fiber fixedly joined to the rotating part. The end of this optic fiber goes through the fixed part and emerges in a case where it is coupled through an optic rotation plane to the end of another optic fiber fixedly joined to the fixed part.

Abstract: Formation of nitrogen oxides and/or soot is obviated by mixing recycled combustion gas with incoming comburant supplied to a burner via a distribution opening and controlling the mass flow rate of combustion gas being recycled with respect to the mass flow rate necessary for the gaseous comburant, the mixture being passed to the burner as a turbulent flow in which the ratio between the kinetic momentum flux of the mixture and the product of the radius of the said distribution opening times the axial movement quantity flux of the mixture has a value at least sufficient so that the said turbulent flow produces a recirculation of the said mixture within the combustion chamber in the form of a toroidal vortex.