| 摘要 |
PURPOSE:To obtain a vibration type mass flowmeter having a simple constitution and a low electric power consumption, by driving by a piezo-electric element attached to a duct. CONSTITUTION:A mass flowmeter is constituted by using a straight pipe instead of a U-shape pipe and a piezo-electric element 7 is distorted by an electric distortion effect by applying an alternating current voltage e1 to the element for driving 7 and then, a duct 1 is driven by transmitting this distortion to the duct 1. At this time, two kinds of vibration patterns of a symmetric bending vibration pattern given in a straight pipe 1 at each moment and the asymmetric bending vibration pattern shown by Coriolis' force acting to a fluid which is flowed in the pipe 1, are vibrated in an overlapped condition. Output signals e2, e3 from piezo-electric elements 63, 64 are added to a phase difference detecting circuit 8 and a phase difference output e0 is obtained. The mass flow rate is obtained because the output e0 is proportional to the mass flow rate. |
