DETECTION METHOD AND DEVICE FOR PACKING MATERIAL

摘要

PROBLEM TO BE SOLVED: To accurately detect a packing state of concrete in a precast concrete molding box even when a temperature difference between air temperature and the concrete is small without influence of the hardness of water in the concrete and ambient temperature. SOLUTION: Characteristics of an oscillation frequency is detected by applying a sine wave of electric signal with a frequency continuously changes in a prescribed range to a piezoelectric speaker 4 and the change of frequency characteristics when contacting the piezoelectric speaker 4 to the concrete packed in the precast concrete molding box is detected based on this characteristics of the oscillation frequency. COPYRIGHT: (C)2003,JPO