Working principle of metal rotameter

The metal rotameter consists of two parts. One part of the rotameter is a tapered tube that gradually expands from bottom to top; the other part of the rotameter is placed in the tapered tube and can move freely up and down along the center line of the tube. rotor. When the rotameter measures the flow of the fluid, the measured fluid flows in from the lower end of the tapered tube, and the flow of the fluid impacts the rotor and generates a force on it (the magnitude of this force varies with the flow); when the flow is large enough , the resulting force lifts the rotor up and lifts it up. At the same time, the measured fluid flows through the annular section between the rotor and the tapered tube wall, and flows out from the upper end. When the force on the rotor when the measured fluid flows is exactly equal to the weight of the rotor in the fluid (called the display weight), the rotor is in a balanced state and stays at a certain height. The analysis shows that the position height of the rotor in the conical tube has a corresponding relationship with the passing flow. Therefore, the corresponding flow value can be obtained by observing the position height of the rotor in the conical tube. In order to prevent the rotor from touching the tube wall when moving up and down the center line of the tapered tube, two methods are usually used: one is to install a guide mandrel in the center of the rotor to keep the rotor on the center line of the tapered tube. Up and down movement, the other is that there are a series of inclined slots on the edge of the rotor disc. When the fluid flows through the rotor from bottom to top, it will bypass the rotor while passing through the inclined slots to generate a reverse thrust, so that the rotor does not go around the center line. Stop rotating to keep the rotor from hitting the tube wall during work. The rotor material of the rotameter can be made of stainless steel, aluminum, bronze, etc.