| 摘要 |
A device for measuring and indicating fluid flow around a flow bend such as an elbow consists of a housing which confines the flow bend and a flow cavity which is connected with the outer side of the curvature of the flow bend. There is a rotor with a number of substantially radial blades which is free to rotate about a fixed axis in the flow cavity. The hydrodynamics of the flow around the bend generates a secondary circulating flow in the cavity which induces a vortex flow therein and the vortex strength increases monotonically with the rate of the bend flow. The rotor, which is substantially co-axial with the vortex, is driven by the vortex to turn in the flow cavity. The rotating speed of the turning rotor is monitored by a sensor which provides the flow rate measurement through a predetermined correlation. For sight flow indication application a view port is provided for visual observation of the rotor which provides a positive indication of fluid flow in the flow band.
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