Which meter type is designed to be accurate over a wide range of flows?

A compound meter is designed to measure flow over a wide range of flow rates, making it particularly useful in situations where the flow can vary significantly. This type of meter combines the features of both positive displacement and velocity measurement techniques. It typically operates in two different modes: one for measuring low flow rates, where the positive displacement mechanism is effective, and another for higher flow rates, where the velocity measurement (often through a turbine or another mechanism) takes over.

This design allows for high accuracy and reliability across a broader spectrum of flow conditions when compared to other meter types, which may be optimized for specific flow ranges. For instance, while positive displacement meters are accurate at low flow rates and Venturi meters are efficient but may lose accuracy at very low flows, the compound meter excels in mixed-flow conditions, providing a comprehensive solution for varying demands in water systems. Electromagnetic meters, while also versatile, are typically more sensitive to specific fluid properties and require certain conditions to function optimally, such as conductivity in the fluid.

Therefore, the compound meter is the best choice when a wide range of flow measurements is needed, making it an ideal instrument for diverse operational scenarios within water distribution systems.