What is Water Flow Meter

A flow meter, in contrast to an ordinary water meter, measures rate of flow rather than volume of flow.

Large Pipe Lines:
In large pipelines, flow meters operate on various differential pressure principles. Flow meters for small flows are usually based on the lifting of a spherical or cylindrical float by the hydraulic action of fluid flowing through a vertical tube.

In a water plant where the water output is variable, such as in cases where more than one pump is used, a flow meter on the main line serves two purposes:

1. The flow meter indicate the flow rates for which the fluoride feeder or feeders must operate.
2. If so designed, flow meters provide an electrical, pneumatic, or hydraulic signal that adjusts the feeder output to correspond to changes in water flow rate.

The electronic metering pump, usually available with programmable signal, is found under relatively constant flow conditions. The pacing meter shown linked to a variable speed motor is useful under variable flow conditions.

Small Pipe Lines:
The type of flow meter used in small pipelines, often known as rotameter, can be located in the water supply line leading to the dissolving chamber of a dry feeder.

Because detention time is a function of water flow rate, the flow must be regulated and maintained at the prescribed value.

In general, a flow meter must be selected on the basis of pipe size and, in particular, the range of flows expected. For greatest accuracy, the range of flow meter should coincide with the range of flows that will be encountered in each particular installation.

Pacing Meter - Variable Speed Motor Control

Pacing Meter - Electronic Metering Pump

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