| 摘要 |
PURPOSE:To prevent the influences of temperature or pressure fluctuations by forming a tuning fork structure of U-shaped tube through which a fluid to be measured flows and a support beam equipped with a magnet on the tip, and exciting with an electromagnetic force and converting in terms of electric quantity with the help of a strain gauge. CONSTITUTION:A permanent magnet 2 of U-shaped tube 1 facing an electromagnet 4 is excited to a proper oscillation number of this system with the assistance of said electromagnet generating an electromagnetic force, so that a fluid running through the U-shaped tube is caused to generate a Coriolis force. Said Coriolis force has a varying magnitude proportional to the mass of a fluid, and the direction of the force coincides with a direction of motion and a direction of the vector product of an angular velocity exciting the U-shaped tube. Since the direction of a fluid is reversed at the input and output side of the U-shaped tube, a twisting torque is generated in the U-shaped tube on account of the Coriolis force on the both legs side. This oscillation torque is proportional to the mass flow of a fluid, and is transferred to a torque beam 6 and then is converted in terms of electric quantity by means of four pieces of strain gauge attached on the beam surface, thus enabling the output proportional to a mass flow to be available. Under this constitution, it is possible to prevent the influence of temperature and pressure fluctuations. |
