NON-CONTACT FLUID FLOW RATE MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a non-contact fluid flow rate measuring apparatus which always achieves an effective and accurate measurement of flow rate whether the pattern of flow in a passage pipe of a fluid to be measured indicates filled water or not. SOLUTION: An ultrasonic oscillation element 11 and an ultrasonic detector 12 are arranged on the upper outer circumferential surface of passage piping 10 at an interval in the axial direction thereof and an ultrasonic signal is radiated through an upper space part of a fluid A to be measured or the fluid from the ultrasonic oscillation element 11 to detect it reflected on the liquid surface of the fluid with the ultrasonic detector 12. The flow velocity of the fluid is determined from a difference in the frequency of the ultrasonic signal between the oscillation and the detection thereof based on the time until the peak value of the ultrasonic signal is detected by the ultrasonic detector 12 and the propagation speed of the ultrasonic signal within the space part or the fluid and the internal sectional area of the piping of the fluid is determined from the arrival time of the ultrasonic signal corresponding to the peak value. In this manner, the flow rate of the fluid is measured from the flow velocity of the fluid and the internal sectional area of the piping thereof. In addition, electrostatic capacitance measuring electrodes are arranged at upper and lower parts of an electrically insulating passage piping to determine the depth of the fluid to be measured from the electrostatic capacitance measured thereby deterring the flow rate from the flow velocity of the fluid to be measured and the internal sectional area of the piping thereof.