Burner

A burner, comprising:

• a support wall which is connectable to a combustion chamber and forms an inlet passageway for introducing a mixture of fuel gas and combustion air into the burner;
• a diffuser wall which delimits an inner space in flow communication with the inlet passageway and which forms a diffuser perforation for the gas mixture to pass from the inner space to an outer side of the diffuser wall where the combustion occurs;
• a pilot chamber formed in the inner space and delimited by a pilot portion of the diffuser wall, forming a pilot perforation of said diffuser perforation, and by a pilot wall at least partially extending into the inner space;
• wherein the pilot chamber delimits a pilot inner volume and forms:
• one or more pilot inlet openings for supplying air alone or a gas-air pre-mixture into the pilot chamber,
• a pilot gas opening which is connectable to a non-premixed fuel gas source and leads into the pilot chamber to directly supply non-premixed fuel gas into the pilot chamber,
• a main chamber formed in the inner space and delimited by a main portion of the diffuser wall, forming a main perforation of said diffuser perforation, and by said pilot wall,
• wherein the main chamber delimits a main inner volume and is in flow communication with the inlet passageway to supply air alone or a gas-air pre-mixture into the main chamber;
• wherein the main inner volume is greater than the pilot inner volume and an area of extension of the main perforation is greater than an area of extension of the pilot perforation;
• wherein the diffuser wall is tubular and coaxial with a longitudinal axis of the burner, the diffuser wall having a first end connected to the support wall and in fluid communication with the inlet passageway, and a closed second end;
• and
• wherein the pilot wall comprises:
• a tubular wall portion arranged in the inner space;
• an annular front wall portion extending between the diffuser wall and the tubular wall portion on a front side of the pilot chamber facing the inlet passageway;
• an annular rear wall portion extending between the diffuser wall and the tubular wall portion on a rear side of the pilot chamber facing the second closed end of the diffuser wall;
• and
• wherein the pilot chamber has an annular shape.