Patent ID: 6055868
Filing Date: 2000-05-02
Classification: G01F

Abstract:
An ultrasonic flow meter comprising:a measuring tube having a uniform outer diameter over the entire length thereof, said measuring pipe being a straight tube; andfirst and second ring shaped oscillators disposed longitudinally forwardly and rearwardly along, and externally of, an outer peripheral surface of a wall of the tube so as to substantially intimately contact inner peripheral surfaces thereof with the outer peripheral surface of the wall of tube;wherein the first of said two oscillators is energized by electric AC energy for generating and propagating a first ultrasonic wave radially inwardly through the wall of the tube toward a center of the tube for deflecting at the center of the tube perpendicularly to the radial direction of inward propagation and for propagating within the tube, the first ultrasonic wave being detected by the second oscillator, and wherein the second of said two oscillators is energized by electric AC energy for generating and propagating a second ultrasonic wave radially inwardly through the wall of the tube toward a center of the tube for deflecting at the center of the tube perpendicularly to the radial direction of inward propagation and for propagating within the tube, the second ultrasonic wave being detected by the first oscillator,the time required for propagating the ultrasonic wave from the upstream first oscillator to the downstream second oscillator being measured and the time required for propagating the ultrasonic wave from the downstream second oscillator to the upstream first oscillator being measured by measuring circuit, and the difference between the measured times being calculated by an arithmetic circuit to determine the velocity of the fluid flowing through the measuring tube.