MEASURING METHOD FOR INTERFACE OF CONTENT IN AIRTIGHT CONTAINER AND MEASURING METHOD FOR AMOUNT OF LIQUID CO2 IN AIRTIGHT CONTAINER AS WELL AS LIQUID LEVEL MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To discriminate liquid phase from the gas phase of even a received matter whose liquid phase cannot be judged by a transmission method or the like, to estimate the height of a level and to measure the amount of the received matter in an airtight container. SOLUTION: A composite probe 6 is pressed, in a prescribed height, to the outer face of a cylindrical airtight container 3 in which liquid CO2 is received. Ultrasonic waves are transmitted into the wall of the container 3 at a prescribed frequency. The ultrasonic waves which are propagated in the circumferential direction of the container 3 are received by the outer face of the container 3 in such a way that they are limited to a narrow hand at a frequency of 1.5 to 2.5 times the frequency of the transmitted ultrasonic waves. The attenuation amount of the received ultrasonic waves is sensed. Whether a measuring point is a liquid phase part or a gas phase part inside the container 3 is discriminated. A discriminating operation is performed in a plurality of points A to D. The boundary of the liquid phase part or the gas phase part is judged so as to judge a level E. Then, the amount of the liquid CO2 received inside the airtight container 3 is measured.