DEVICE FOR MEASURING THICKNESS OF VESSEL STEEL PLATE

PROBLEM TO BE SOLVED: To measure the thickness, even in the case of a vessel having a vessel mirror part formed by a spherical or conical curved surface such as a reactor (reaction vessel) and various kinds of obstructions at a vessel barrel. SOLUTION: A first thickness of the vessel steel plate calculated when the start time of a bottom echo monitoring gate 42 for detecting the voltage value of echo height on the bottom surface of the vessel steel plate is used as a first start time is compared with a second thickness of the vessel steel plate calculated when the start time of the gate 42 is moved to a second start time earlier than the first start time by a predetermined time. While the second thickness is smaller than the first thickness, the start time of the gate 42 is moved to a time earlier by the predetermined time. When the second thickness matches with the first thickness, the start time of the bottom echo monitoring gate 42 is fixed. COPYRIGHT: (C)2007,JPO&INPIT