Which type of flow meter is specifically used for measuring liquid flow?

The positive displacement flow meter is specifically designed for measuring the flow of liquids. Its operation is based on trapping a fixed quantity of liquid and then counting the number of these fixed volumes that pass through the meter over time. This type of flow meter is particularly effective for precise measurement of liquid flow rates, especially in applications where accuracy is critical.

Other flow meters, while useful for measuring liquid flow, can serve a broader range of applications. For example, a rotameter measures flow based on the variable area principle, which can be effective for gases as well as liquids. An electromagnetic flow meter operates based on the principle of electromagnetic induction and is typically suited for conductive liquids, but it may not be ideal for all liquids, especially those that are non-conductive. Ultrasonic flow meters measure flow based on the time it takes for ultrasonic pulses to traverse a section of the fluid, which can be used for both liquids and gases, adding to their versatility but not specificity for liquids.

In contrast, positive displacement meters are specifically tailored for liquids, ensuring reliable and accurate flow measurement in applications such as chemical processing, food and beverage, and other industries where fluid properties may vary.