| 摘要 |
A meter includes a casing (1) with a fluid passage (2), in which two transducer mountings (3, 4) arranged at a distance (Lb) from each other support two transducers (5, 6) which are acoustically opposed to each other. Between the transducers (5, 6) there is a distance (Lu) over which they transmit and receive sound pulses through a fluid which in a direction (a) flows through the fluid passage (2). On the basis of the transit times of the sound pulses over the distance (Lu) both countercurrently with and countercurrently to the direction of flow (a), e.g. the velocity of the flow of the fluid is then calculated. A compensating device (8, 9) is arranged between at least one of the transducers (5, 6) and one of the transducer mounts (3, 4). The compensating device (8, 9) is made of a material having a known function of thermal expansion and having such a length that a longitudinal change, caused by a change in temperature of the fluid, of the distance (Lb) between the transducer mounts (3, 4) and, thus, of the distance (Lu) between the transducers (5, 6) is essentially compensated for by an opposite longitudinal change of the compensating device (8, 9). |
