Gas-fired heating apparatus

A gas-fired heating apparatus comprising

• a nearly or completely closed combustion chamber (2);
• at least one atmospheric gas burner (5) arranged within said nearly or completely closed combustion chamber (2);
• a complete premixing gas/air supply system (8) associated with said at least one atmospheric gas burner to supply fuel gas and said combustion air to said at least one atmospheric gas burner, said complete premixing gas/air supply system (8) having an entrance (8a);
• an oscillation-damping air supply chamber (11, 11′, 11″) connected to said entrance (8a) of the premixing gas/air supply system (8), said oscillation-damping air supply chamber (11, 11′, 11″) having at least one air inlet (12, 12′, 12″) for admitting said combustion air and said at least one air inlet (12, 12′, 12″) being arranged outside of said combustion chamber (2);
• a fuel gas feed nozzle (10) arranged inside of said air supply chamber (11, 11′, 11″) and at said entrance (8a) to said complete premixing gas/air supply system (8), wherein said fuel gas feed nozzle (1) is in communication with an inlet for said fuel gas arranged outside of said combustion chamber;
• and not including a blower that assists in supplying said combustion air to said at least one atmospheric gas burner in operation;
• wherein said oscillation-damping air supply chamber (11, 11′, 11″) has a predetermined interior volume adjusted to damp acoustic oscillations in said combustion chamber (2).

A gas-fired water heater comprising

• a water tank (1) for storing heated water;
• a closed or nearly closed combustion chamber (2) arranged underneath the water tank;
• an exhaust flue (3) communicating with the combustion chamber (2) and extending centrally through the water tank (1);
• at least one atmospheric gas burner (5) arranged within said nearly or completely closed combustion chamber (2) so as to operate without assistance of a blower that supplies combustion air;
• a complete premixing gas/air supply system (8) associated with said at least one atmospheric gas burner to supply fuel gas and said combustion air to said at least one atmospheric gas burner, said complete premixing gas/air supply system (8) having an entrance (8a);
• an oscillation-damping air supply chamber (11, 11′, 11″) connected to said entrance (8a) of the premixing gas/air supply system (8), said oscillation-damping air supply chamber (11, 11′, 11″) having at least one air inlet (12, 12′, 12″) for admitting said combustion air arranged outside of said combustion chamber (2);
• and
• a fuel gas feed nozzle (10) arranged inside of said air supply chamber (11, 11′, 11″) and at said entrance (8a) to said complete premixing gas/air supply system (8), wherein said fuel gas feed nozzle (1) is in communication with an inlet for said fuel gas arranged outside of said combustion chamber;
• wherein said oscillation-damping air supply chamber (11, 11′, 11″) has a predetermined interior volume adjusted to damp acoustic oscillations in said combustion chamber (2).