PURPOSE: To settle the problem of corrosion of a burner nozzle and others due to acid vapor by connecting a hot air jet nozzle to the lower end of a downcomer pipe of a pickling tank and also by connecting the upper end of the downcomer pipe and a hot air producing device with a flow passage interrupting means interposed between them.
CONSTITUTION: A hot air producing device 3 equipped with a gas burner 1 and a pickling tank 4 are installed as separate bodies, and a downcomer pipe 5 of the pickling tank 4 and the hot air producing device 3 are connected with a flow passage interrupting means 8 interposed between them. Thereby flowing of gas between them can be interrupted completely by a distance between them and by the flow passage interrupting means 8 after stoppage of an operation of the gas burner 1 and the possibility that acid vapor flows onto the hot air producing device 3 side from the hot air jet nozzle 6 side and corrodes a gas burner nozzle and others is eliminated. Since an air compressor 2 is used for supply of combustion air to the gas burner 1, besides, hot air can be jetted from small holes 6c of hot air jet nozzles 6 disposed in the bottom part of the pickling tank 4 and thereby the efficiency of acid pickling can be increased.
SAKAMOTO EIGO
MINAMI SATORU
KAWAMOTO MASAO
KATSURA SEIKI MFG
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