Pressure Differential Meter
When flow is within a pipe, the flow is often measured using a pressure differential meter. The
pressure differential meter consists of a primary element, a transmitter,
and a receiver. The primary element,
shown below, consists of a tube with a constriction in it. When water
flows through the constriction, the velocity of the water increases.
As a result, the pressure of the water decreases.
A transmitter measures
the pressure of the water before and after the constriction in the pipe and
calculates the difference in pressure between the two locations. The
transmitter in turn sends the reading to a receiver which converts the signal from
pressure to flow to be read by the operator.