ATOMIC ABSORPTION ANALYSIS FOR MEASURING AND CONTROLLING THE AMOUNT OF A METAL VAPOR IN VAPOR DEPOSITION COATING LINE AND APPARATUS THEREFOR

摘要

A metal vapor 12 passing through a guide duct 13 from a vapor source 10 to a steelstrip 1 is sampled through a takeoff pipe 14 to a measuring chamber 15. The metal vapor isirradiated with a measuring beam 20 in the chamber 15, to detect the absorbance of luminousenergy in the metal vapor. The detected value of absorbance is used for the quantitativecalculation of the metal vapor 12 passing through the guide duct 13, and the opening ratio of ashutter 17provided in the guide duct 13 is adjusted on the basis of the calculation result so asto control the flow amount of the metal vapor 12 passing through the guide duct 13. In thecase where a large amount of the metal vapor 12 passes through the guide duct 13, theamount of the metal vapor 12 reaching the measuring beam 20 is reduced by partiallydischarging the metal vapor 12 from the measuring chamber 15. Since the deposition amountof a plating metal is directly controlled in response to the amount of the metal vapor12passing through the guide duct 13, the amount of a deposited plating layer is controlled withhigh accuracy and with a quick response time in a continuous vapor deposition coating line.