Abstract: In a burner assembly connected with a combustion chamber at a fuel inlet of said combustion chamber, the improvement of which comprising a fuel duct which is connected at its one end to said fuel inlet and contains therein a fuel injection nozzle, ignition rod and air-fuel mixture diffuser, a blower means which has an outlet for blowing an air through said outlet of the blower means and said fuel duct into said combustion chamber, and a conduit member coupled to said inlet of the blower means, whereby pneumatic oscillation plane progressive waves are converted into plane stationary waves to thereby reduce progressive energy of said pneumatic oscillation plane progressive waves.