Patent ID: 9746176
Date: 2017-08-29
CPC Classifications: F23C,F23D,F23L,F23N,F23Q,F24H

Claim:
1. A burner assembly, comprising: a burner; a blower configured to supply pre-mixed air and fuel gas mixture to the burner, the blower including a blower inlet; a venturi including a venturi inlet, a venturi outlet, and a reduced pressure zone intermediate of the venturi inlet and the venturi outlet, the blower inlet being communicated with the venturi outlet such that the blower pulls air through the venturi; at least one gas valve communicated with the reduced pressure zone such that the at least one gas valve supplies fuel gas to the reduced pressure zone at a fuel gas flow rate corresponding to a pressure in the reduced pressure zone; and an air flow restrictor located upstream of the reduced pressure zone and movable between an open position and a restricted position, such that in the restricted position air flow through the venturi inlet is still permitted but is restricted by the air flow restrictor, wherein the air flow restrictor comprises a disc-shaped valve element, the restrictor defining an annular flow path around the disc-shaped valve element when the air flow restrictor is in the restricted position.