Abstract: A process and apparatus for mixing two fluids by generating a pressure drop across a pair of surfaces each forming a wall of a mixing chamber and confronting one another while separating a respective source of fluid from the mixing chamber. The surfaces being provided with mutually aligned and opposing apertures thereby accelerating the respective gases through the apertures in opposing jets. The resulting mixture of the fluids is conducted away from the chamber in a direction substantially parallel to the surfaces.

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.

Abstract: A modular boiler having a cylindrical combustion chamber made of three modules and a module comprising a cover and a module comprising an expansion vessel mounted coaxially on the boiler adjacent the combustion chamber at opposite ends thereof. The cover has a frustro-conical configuration with the inner walls thereof diverging from an opening in the cover toward the interior of the combustion chamber at an angle of between 30.degree. and 110.degree.. The combustion chamber is formed of three castings that define the cylindrical combustion chamber and six axial hot gas flow paths spaced circumferentially from each other and disposed axially of and radially of the combustion chamber. Hot gases from the downstream end of the combustion chamber are recirculated to the upstream end of the combustion chamber to improve the combustion.

Abstract: A modular boiler having a cylindrical combustion chamber made of three modules and a module comprising a cover and a module comprising an expansion vessel mounted coaxially on the boiler adjacent the combustion chamber at opposite ends thereof. The cover has a frustro-conical configuration with the inner walls thereof diverging from an opening in the cover toward the interior of the combustion chamber at an angle of between 15.degree. and 55.degree.. The combustion chamber is formed of three castings that define the cylindrical combustion chamber and six axial hot gas flow paths spaced circumferentially from each other and disposed axially of and radially of the combustion chamber. Hot gases from the downstream end of the combustion chamber are recirculated to the upstream end of the combustion chamber to improve the combustion.

Abstract: A modular boiler having a cylindrical combustion chamber made of three modules and a module comprising a cover and a module comprising an expansion vessel mounted coaxially on the boiler adjacent the combustion chamber at opposite ends thereof. The cover has a frustro-conical configuration with the inner walls thereof diverging from an opening in the cover toward the interior of the combustion chamber at an angle of between 30.degree. and 110.degree.. The combustion chamber is formed of three castings that define the cylindrical combustion chamber and six axial hot gas flow paths spaced circumferentially from each other and disposed axially of and radially of the combustion chamber. Hot gases from the downstream end of the combustion chamber are recirculated to the upstream end of the combustion chamber to improve the combustion.