| 摘要 |
PURPOSE:To increase measuring accuracy by a simple construction by giving a curved conduit a torsional oscillation that is stable against an external oscillation and controlling the amplitude of the curved conduit to an always constant value regardless of a flow rate. CONSTITUTION:A curved conduit 1 comprising a tubular body which has inlet outlet openings 2 and 3, respectively, both for a fluid to be measured and is symmetric with respect to a first axis XX' is fixedly connected to a support member 4 and constructed so as to be rotatable about a second axis YY'. Magnets 51 and 61 are provided in positions C and D, respectively, and, opposing to these magnets, electromagnetic coils 5 and 6 excited by AC currents with phases different from each other by 180 deg. are provided. When AC current flows through the coils 5 and 6, these coils 5 and 6 are alternately attracted and repulsed by the magnets 51 and 61, respectively, and the curved conduit 1 torsionally oscillates about the first axis XX' with a natural frequency omegato produce a Coriolis force in a Z direction, vertically oscillating with another natural frequency. The amplitudes of these oscillations are detected by amplitude detectors 7-1 and 7-2 and controlled to constant values through a phase-shifting circuit 102, a rectifier 104 and the like. The quantity of the control is indicated by an indicator 105 as the Coriolis force, that is, a mass flow rate. |
