Which metering device uses a rotating element to measure flow?

The turbine flow meter is a type of metering device that specifically utilizes a rotating element to measure the flow of fluids. This device operates based on the principle that as fluid passes through the meter, it causes a turbine wheel to spin. The speed of the turbine's rotation correlates directly with the flow rate of the fluid. The faster the fluid flows, the quicker the turbine spins, allowing for an accurate measurement of the volumetric flow rate.

This capability makes turbine flow meters particularly suitable for measuring the flow of liquids and gases in various applications, including HVAC systems. They are known for their high accuracy and ability to handle a wide range of flow rates.

In contrast, the other types of flow meters mentioned do not employ a rotating element for measurement. Positive displacement flow meters measure the volume of fluid through chambers that fill and empty, while rotameters utilize a floating element in a graduated tube to indicate flow. Ultrasonic flow meters use sound waves to measure flow velocity, without any moving parts. Therefore, these devices do not fulfill the criteria of using a rotating element for flow measurement.