| 摘要 |
Method and device for speed difference measurement in strip casting where a melt (4) is pressed between a travelling belt (2) and a casting drum (1) rotating along with the belt. For measuring the speed difference between the speed of the travelling belt and the peripheral speed of the casting drum, the belt is provided on one side with a raster of alternately darker and lighter stripes, and a number of measuring zones (7) having the same width as that of said raster are arranged around the periphery of the casting drum. Each measuring zone (7) comprises a transducer built up of a number of photocells which, via optical conductors opening out into the measuring zones, can be activated by said raster. When, during the casting operation, a measuring zone has arrived at a given measuring region, the number of activated photocells is read. The same procedure is repeated when the same transducer arrives at the end of the measuring region. With knowledge of the extension of the measuring zones and the measuring region and of the number of photocells in each zone, the speed difference, expressed as a percentage, together with the difference in activated photocells can be calculated. |
