| 摘要 |
Gas meter has two ultrasonic transducers (22,24) arranged at either end of a measurement conduit (20). Each of the transducers is held in an assembly (30,32) of cross section larger that the transducer cross-section. At least the downstream transducer (24) has a filter (46) placed within its mounting assembly (32), so that it extends over the whole transducer cross section. The filter is an effective dust trap, but still allows the passage of ultrasonic waves. |
