| 摘要 |
An ultrasonic liquid quantity measuring apparatus directs a collimated beam of ultrasonic energy from a transmitter transducer (14) through a conveyor (15) into the liquid (11) in a container (10) perpendicular to the top liquid surface. The ultrasonic beam travels with little loss through a tube (20) connected to the conveyor (15) until it reaches the top liquid surface. At this time the energy is reflected and detected with a receiver transducer (14). A microprocessor (34) measures the total signal round trip travel time representing the height of the liquid (11). Using several ultrasonic transducers (14) and knowing the size and shape of the container (10) the quantity of liquid (11) in the container (10) is accurately determined. A calibration (known reflected signal time) transducer (14a) is used to compensate for the change in propagation velocity due to temperature change in the liquid (11). Conventional electronic circuitry including the microprocessor (34) is employed to coordinate the operation of the several transducers (14 and 14a) automatically.
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