| 摘要 |
Coriolis mass flow meter which includes a ferromagnetic drive mechanism and ferromagnetic velocity sensors. The drive mechanism includes a drive coil (503); a ferromagnetic drive keeper (500) affixed to a flow conduit (130) of the meter so that it is partially disposed in the field from the drive coil; a magnet (502) for orienting the ferromagnetic domains of the drive keeper; and means (185) for applying a drive signal to the drive coil. The velocity sensor includes a sensor coil (604); a ferromagnetic sensor keeper (600) affixed to the flow conduit (130) so that it is partially disposed in the field drawn across the sensor coil; a magnet (602) for orienting the ferromagnetic domains of the sensor keeper, disposed so that a portion of its magnetic field passes through the sensor coil; and means (30) for detecting a current induced in the sensor coil by changes in the sensor keeper position. The drive mechanism oscillates the flow conduit in response to the variable magnetic field produced by the drive signal. As a side leg (18, 20) of the flow conduit oscillates in response to the drive mechanism and Coriolis forces, so too does the ferromagnetic sensor keeper. As a result, the magnetic field passing through the sensor coil varies and a signal is induced therein which provides a measure of the velocity of the side leg of the flow conduit. |
