| 摘要 |
PURPOSE:To obtain a monitoring device for film thickness which is easy to maintain and control by utilizing the fact that the temp. difference of a plate material before and after the vapor deposition of a plating metal is proportional to the film thickness. CONSTITUTION:Radiation thermometers 13, 14 are provided in a vapor deposition chamber 7 of a plating line by vacuum deposition, and signal converters 15, 16 are respectively connected thereto. A steel strip 2 up-coiled from an un-coiler 1 is passed through a pretreatment installation 3 and is conducted to the chamber 7 through a differential pressue chamber group 6 constituted of partition walls 4 and seal rolls 5. The pressures in the group 6 and the chamber 7 are made successively lower and the plating metal is deposited by evaporation on the strip 2 while said strip passes over the evaporation crucible 8 in the chamber 7. The radiation of the steel strip 2 before and after the vapor deposi-tion is detected with the thermometers 13, 14 and is converted to electrical signals. The respective signals are converted to temp. by the converters 15, 16. The film thickness of the plated plate material and the temp. elevation of the plate are proportional in the plating by vapor deposition and therefore the film thickness is monitored by maintaining the difference between the temps. detected with the converers 15, 16 at a prescribed value. |
