Nutating and piston disk water meters are examples of what type of meters?

Nutating and piston disk water meters are categorized as displacement meters. This classification stems from their operational principle, which involves measuring water flow by displacing a known volume with each cycle of the meter. In the case of nutating meters, a disk rotates due to water flow, causing a measuring chamber to fill and empty, thus displacing a fixed volume of water with each rotation. Similarly, piston meters utilize a piston that moves back and forth, displacing water to measure the total flow.

Displacement meters are commonly used for accurate measurement in applications where precision is critical, such as in residential and smaller commercial settings. They are particularly effective at low flow rates and can maintain accuracy over time, making them a preferred choice in many metering applications.

Other types of meters, like velocity meters, measure flow rate through the velocity of the water moving past a point rather than displacing a fixed volume. Magnetic and electromagnetic meters utilize different principles involving magnetic fields to measure flow rates, which do not pertain to the displacement measurement method used by nutating and piston disk meters. This is why displacement meters is the appropriate classification for nutating and piston disk water meters.