Abstract: A low NO.sub.x atmospheric gas burner is provided, which includes at least one burner tube having a plurality of gas outlet orifices terminating in a burner bed, and a plurality of plates disposed above the burner tube within the reach of the flame, which plates lower the temperature and effect a stepped combustion. According to the invention, the plates extend parallel to, and on opposite sides of, the orifices provided in the burner tube, and the orifices are arranged in a line parallel to the burner axis. The plates are connected direct to the burner tube substantially throughout the entire length of their lower edges.

Abstract: A heating boiler having a vertical, completely premixing burner tube arranged in a space shut off at the top includes concentrically relative to the burner tube a helical water tube surrounded by an upwardly extending flue gas discharge jacket. The burner tube comprises a lower circumferentially closed tubular mixing portion and an upper portion having burner ports formed by a plurality of stacked alternately flat and radially corrugated annular discs held together by a flat top plate connected through a bolt or the like to a cross piece or the like wedged in an internally tapered upper end of the circumferentially closed tubular mixing portion.