Metal Rotameter

The float of the metal tube rotameter is installed vertically in the tapered measuring tube. Due to the action of the fluid, it can move freely up and down in the tapered tube. The annular area formed by the tapered tube and the maximum outer diameter of the float changes with the position of the float. When the flow rate of the fluid is stable at a certain value, the float is also in a state of dynamic balance at a certain position, and the annular area between it and the tapered tube also remains constant. At this time, the float is subject to three forces: the downward weight of the float, the upward buoyancy force and the power of the fluid. These three forces are balanced. According to the Bernouli's equation of fluid dynamics, the force balance equation and the continuity theorem of fluids, the average instantaneous flow rate of fluid through the annular area can be calculated.