Float flowmeter also known as a variable-area flowmeter

The float flowmeter, also known as a variable-area flowmeter (or float-type flowmeter), is a device that determines flow rate by measuring the position of a moving component within a straight pipe. Its operating principle is as follows: inside a vertical tapered tube that widens from bottom to top, a float with a circular cross-section is supported by the hydrodynamic force of the fluid, allowing it to move freely up and down within the tube.