| 摘要 |
An ultrasonic apparatus for determining the amount of liquid in a container of known volume includes at least a pair of ultrasonic transducers which are mounted a known distance apart relative to the liquid surface so that the ultrasonic energy reflected from the liquid surface traverses the following paths: (1) from a first of the transducers vertically to the liquid surface, and (2) from the first transducer to the liquid surface and then to the second transducer. A circuit measures the time of travel T corresponding to path (1) above, and T1 corresponding to one-half the travel time of path (2) above. The height H of liquid above the transducers is determined by solving the equation: <IMAGE> where S is the known distance between transducers, T is the travel time of ultrasonic energy directly or vertically to the liquid surface and T' is one-half the travel time between the two transducers reflected off the liquid surface. |
