GAS CONTROL APPARATUS FOR ATOMIC ABSORPTION ANALYTICAL APPARATUS

PURPOSE:To avoid a backfire and to prevent soot generation in extinguishing a flame, by a method wherein the supply of nitrous oxide is stopped while air is sent when power failure occurs during the combustion of a nitrous oxide- acetylene flame and the supplies of both of them are subsequently stopped in the order of acetylene and air. CONSTITUTION:An air supply pipe P1' having a solenoid valve V1 arranged thereto and a nitrous oxide supply pipe P1'' having a solenoid valve V2 arranged thereto are connected to a combustion aid gas introducing pipe P1 which is, in turn, opened to a burner B through a solenoid valve V3 and a combustion gas introducing pipe P2 receiving the supply of acetylene is opened to the burner B through a solenoid valve V4. When power failure occurs during the combustion of a nitrous oxide-acetylene flame, the valve V2 is closed to stop the supply of nitrous oxide and the valve V1 is opened to lower a combustion speed while sending air. Subsequently, the valves V4, V3 are closed so as to leave a predetermined delay time and the supplies of both of them are stopped in the order of acetylene and air to extinguish the flame. As a result, a backfire is avoided and soot generation can be prevented.