How does a variable area flow meter measure flow rate?

A variable area flow meter measures flow rate based on the vertical position of a float within a tapered tube. As the fluid flows through the meter, it lifts the float to a position that corresponds to the flow rate. The tube is designed such that as the flow rate increases, the fluid's velocity increases, creating a lower pressure at the point where the float resides. This pressure drop allows the float to rise to a new level, indicating the increased flow rate. The position of the float can be read on a scale, which directly correlates to the flow rate of the fluid passing through the meter.

This method is straightforward and effective, making it a popular choice for various applications where monitoring fluid flow is necessary. It provides a visual representation of flow rate, contributing to its usability in both industrial and laboratory settings.