Premix burner with firing rate control

摘要

An apparatus for heating a process chamber. The apparatus includes a furnace structure that defines a reaction zone that communicates with the process chamber. A burner structure defines a burner port and communicates with the reaction zone through the burner port. The burner structure includes a plurality of mixer tubes. The mixer tubes mix fuel and oxidant and define flow paths for the fuel and oxidant. Each of the flow paths extends through a respective mixer tube. A valve assembly interrupts a flow of fuel and oxidant along one of the flow paths. The valve assembly is shiftable between a closed condition interrupting a flow of fuel and oxidant along the flow path, and an open condition not interrupting the flow. A controller operates to shift the valve assembly into or out of its open condition. The controller has a mode of operation including consecutive cycles in which the valve assembly is shifted into and out of its open condition.