Gas flow rate control device and brazing device with flow rate of frist gas and flow rate of second gas controlled on the basis of set ratio

摘要

A gas flow rate control device disposed between a gas burner and a combustible gas source and a burning-supporting gas source connected to the gas burner has gas flow rate setting means for setting a flow rate of the combustible gas to be supplied to the gas burner, gas ratio setting means for setting a gas ratio between the flow rate of the combustible gas and a flow rate of the burning-supporting gas to be supplied to the gas burner, a first control valve for controlling the amount of combustible gas supplied to the gas burner, a second control valve for controlling the amount of burning-supporting gas supplied to the gas burner, and control means for controlling the first and second control valves on the basis of the set flow rate of the combustible gas and the set gas ratio so that the amounts of the combustible gas and the burning- supporting gas supplied to the gas burner correspond to the flow rates set.