Flatness-measuring device, hot-rolling mill and method for operating a flatness-measuring device

A flatness-measuring device (1) for measuring flatness of a hot-rolled strip (2) within a hot-rolling mill, comprising:

• deflection rollers (3, 5, 7), including
• an entry-side deflection roller (3) for contacting a first large side of the hot-rolled strip (2),
• an exit-side deflection roller (5) for contacting the first large side of the hot-rolled strip (2), and
• a central deflection roller (7) arranged between the entry-side deflection roller (3) and the exit-side deflection roller (5) with respect to a strip running direction (6) of the hot-rolled strip (2),
• wherein the central deflection roller (7) is placed against a second large side of the hot-rolled strip (2) opposite from the first large side of the hot-rolled strip (2), and
• wherein the central deflection roller (7) is used as a flatness-measuring roller;
• a sensing apparatus (8) for sensing an actual position (LIst) of the hot-rolled strip (2);
• and
• an adjusting apparatus (9),
• wherein the adjusting apparatus (9) is connected to the sensing apparatus (8) and to one of the deflection rollers (3, 5, 7), and
• wherein the adjusting apparatus (9) is designed to vary an angle (α) between a longitudinal central axis (10) of the one of the deflection rollers (3, 5, 7) connected to the adjusting apparatus (9) and a longitudinal axis (11) of the flatness-measuring device (1) running transversely to the deflection rollers (3, 5, 7) based on a deviation of the actual position (LIst) of the hot-rolled strip (2) from a predefined target position (LSoll) of the hot-rolled strip (2).