A high turn-down burner adapted to receive a fuel flow for combustion. The burner includes a housing having a side wall with an interior surface forming an inner periphery, a bottom wall adjoining the side wall, a top wall adjoining the side wall and a plurality of apertures disposed on the side wall; a supply tube adapted through the top wall of the housing, the supply tube including a side wall having an outer surface forming an outer periphery, a top end, a bottom end, wherein the supply tube is adapted to receive the fuel flow at the top end of the supply tube; and a disk having an opening adapted to accommodate the supply tube, wherein the disk is configured to slide along a length of the supply tube within the space delineated by the inner periphery of the housing and the outer periphery of the supply tube.

A high turn-down burner adapted to receive a fuel flow for combustion. The burner includes a housing having a side wall with an interior surface forming an inner periphery, a bottom wall adjoining the side wall, a top wall adjoining the side wall and a plurality of apertures disposed on the side wall; a supply tube adapted through the top wall of the housing, the supply tube including a side wall having an outer surface forming an outer periphery, a top end, a bottom end, wherein the supply tube is adapted to receive the fuel flow at the top end of the supply tube; and a disk having an opening adapted to accommodate the supply tube, wherein the disk is configured to slide along a length of the supply tube within the space delineated by the inner periphery of the housing and the outer periphery of the supply tube.

A premixing apparatus has: a butterfly valve and a changeover valve for changing over, between high and low, a ventilation resistance in an air supply passage and in a gas supply passage, respectively; and an interlocking mechanism to open or close the changeover valve in interlocking with the opening or closing of the butterfly valve. In either of the small-capacity state in which the ventilation resistance in the air supply passage and in the gas supply passage is made high to attain a small-capacity state or in a large-capacity state to attain a large-capacity state, adjustments are arranged to be made to make appropriate the excess air ratio of the air-fuel mixture. An interlocking mechanism is constituted: to maintain the changeover valve in a fully-closed state when the butterfly valve lies in a predetermined first rotation angle range inclusive of the closed posture; and to maintain the changeover valve in a fully-opened state when the butterfly valve lies in a predetermined second rotation angle range inclusive of the opened posture. The rotation angle of the butterfly valve at which the excess air ratio of the air-fuel mixture becomes the predetermined appropriate value within the first rotation angle range is set to a closing-side stop angle of the butterfly valve. The rotation angle of the butterfly valve at which the excess air ratio of the air-fuel mixture becomes the predetermined appropriate value within the second rotation angle range is set to an opening-side stop angle of the butterfly valve.

A modulating burner apparatus includes a burner and a blower placed upstream of the burner. A venturi is placed upstream of the blower. A damper valve is placed upstream of the venturi. The damper valve has an open position and a restricted position. A smaller gas valve and a larger gas valve are communicated with the venturi. A controller is operably associated with the system to select a position of the damper valve and to select the appropriate one of the gas valves so as to provide a low output operation mode and a high output operation mode, which in combination provide an overall turndown ratio of at least 25:1.

A modulating burner apparatus includes a burner and a blower placed upstream of the burner. A venturi is placed upstream of the blower. A damper valve is placed upstream of the venturi. The damper valve has an open position and a restricted position. A smaller gas valve and a larger gas valve are communicated with the venturi. A controller is operably associated with the system to select a position of the damper valve and to select the appropriate one of the gas valves so as to provide a low output operation mode and a high output operation mode, which in combination provide an overall turndown ratio of at least 25:1.

A turn down ratio (TDR) damper which controls an amount of gas and air flowing in the TDR damper and deliver the controlled gas and air to a turbo fan is disclosed. The TDR damper includes: air passages comprising a first air passage and a second air passage, the first air passage and the second air passage separately formed so that the air move through each path; gas passages comprising a first gas passage and a second gas passage, the first gas passage and the second gas passage separately formed so that the gas move through each path; and opening and closing means for opening and closing the second air passage and the second gas passage at the same time. The air passages and the gas passages may be separately formed and reached outlets connected to the turbo fan so that the air and gas may be delivered to the turbo fan through a separate path.

A gas burner includes a burner body that defines a fuel chamber and a plurality of flame ports. The plurality of flame ports are configured for directing a flow of fuel and air out of the fuel chamber. The plurality of flame ports are distributed along a circumferential direction on the burner body such that the plurality of flame ports are uniformly spaced from a center of the fuel chamber along a radial direction. The plurality of flame ports may be oriented to direct flames away from a void within the plurality of flame ports.

A gas burner includes a burner body that defines a fuel chamber and a plurality of flame ports. The plurality of flame ports are configured for directing a flow of fuel and air out of the fuel chamber. The plurality of flame ports are distributed along a circumferential direction on the burner body such that the plurality of flame ports are uniformly spaced from a center of the fuel chamber along a radial direction. The plurality of flame ports may be oriented to direct flames away from a void within the plurality of flame ports.

A combustion system includes a premix blower system and the premix blower system includes an additional air inlet with an adjustable opening which includes an additional reversibly pluggable air intake. The adjustable opening of the additional air inlet can be opened at higher elevations to compensate for thinner air.

A combustion system includes a premix blower system and the premix blower system includes an additional air inlet with an adjustable opening which includes an additional reversibly pluggable air intake. The adjustable opening of the additional air inlet can be opened at higher elevations to compensate for thinner air.