To provide a method for accurately measuring a gap between the surface of a cooling roll and the tip of a nozzle under a high temperature atmosphere.
When a molten metal is ejected to the surface 2 of a cooling roll in the high speed rotation from an ejection nozzle 3 and cooled rapidly and solidified, to manufacture a metal thin strip, a gap L between the surface 2 of the cooling roll 1 and the tip 4 of the nozzle 3 is measured. At this time, a step having a prescribed dimension H is provided in at least one of end sections of a surface of the nozzle tip 4 in the width direction. The nozzle 3 is relatively moved in a direction 9 perpendicular to a projection direction of a light projector and in the width direction with respect to both of the light projector and light receiver, then the projection light is scanned on a range including the step provided in the nozzle 3 in the width direction of the nozzle 3 to measure the dimension (h) of the step. A shift between the dimension (h) of the step and prescribed dimension H is calculated, thereby calibrating the measured gap between the surface 2 of the cooling roll 1 and the nozzle tip 4.
KUROKAWA KATSUMI
ISHIZUKA HARUHIKO
SATO TORU
YANAGIMOTO TAKAYUKI
