| 摘要 |
PURPOSE:To obtain the titled flow meter having a high accuracy by fetching a voltage induced in a conductive fluid by supplying a reference current signal to an exciting coil, sampling and outputting it, and driving a flow rate detector consisting of a large diameter measuring tube. CONSTITUTION:A flow meter 1 is constituted of a large diameter measuring tube 2 through which a conductive fluid passes, an exciting coil 3 and a pair of electrodes 4, 4. Also, a transducer 5 brings an output signal induced in the electrodes 4, 4 to sampling at a prescribed interval, executes a prescribed signal processing, and outputs a constant-current of square waves as a reference current signal through an exciting circuit 8. As a result, an alternating constant- current generated from the circuit 8 is amplified 12 and applied to the coil 3. Accordingly, by setting resistance values of current detecting resistances 14, 16 to suitable values, this alternating constant-current can be amplified to magnitude of an exciting current which can drive the tube 2, therefore, as for the circuit 8, a circuit for a small diameter detector can be used. As a result, the transducer 5 can be manufacture in a small size and at a low cost, and the one which has an excellent operability is obtained.
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