According to the measurement principle, it is divided into speed type water meter and volume type water meter.

(1) Velocity water meter: a water meter installed in a closed pipeline and composed of a moving element, which is directly driven by the speed of the water flow to obtain the power speed.

Typical speed water meters include rotary-wing water meters and screw-wing water meters. There are single-stream water meters and multi-stream water meters in rotary-wing water meters.

Screw-wing water meter

(2) Volumetric water meter: Installed in the pipeline, it is a water meter composed of a number of chambers of known volume that are filled and discharged with fluid successively and a mechanism driven by the fluid, or quantitative discharge water meter for short.

Volumetric water meters generally adopt a piston structure.