| 摘要 |
The level of a liquid (14) is detected by an ultrasonic arrangement comprising a transmitter (10) and a receiver (12). The transmitter (10) has a vertical array of transmitter segments (16) which transmit sequentially, while the receiver (12) is a single transducer. The difference in transmission time in liquid and gas allows a digital, depth representative output to be generated. The transmitter (10) is formed by securing a single sheet (20) of piezo polymer film over a printed circuit board (24) having a conductive pattern defining the segments (16). Other embodiments provide analogue outputs, and non-linear outputs representative of volume in irregular tanks. |
