Which type of flow measuring device can be installed in a pipe that is flowing full?

A Venturi meter is designed to accurately measure flow in a pipe that is flowing full. It operates on the principle of Bernoulli's equation, which relates the velocity of a fluid to its pressure. The unique design of a Venturi meter includes a tapered inlet, a throat (the narrowest section), and a gradually expanding outlet. When fluid flows through this configuration, its velocity increases as it passes through the throat, resulting in a decrease in pressure. By measuring the pressure difference between the wider pipe sections and the throat, the flow rate can be calculated reliably.

While an orifice plate can also measure flow in a full pipe, it is less efficient than a Venturi meter in terms of pressure drop and accuracy. Magnetic flow meters do work in full pipe conditions and are suitable for conductive liquids, but they rely on different principles and are not specifically designed for the precise pressure changes utilized in a Venturi meter. Ultrasonic flowmeters can measure flow in both full and partially full pipes but often do so by sending sound waves through the liquid, which involves its own set of limitations and conditions for operation.

Thus, the Venturi meter stands out in its ability to consistently provide accurate measurements for full pipe flow scenarios.