A flow meter that uses a small hole in a plate to measure flow is called what?

The flow meter that utilizes a small hole in a plate to measure flow is known as an orifice meter. This device operates on the principle of pressure differential: as fluid flows through the orifice, it experiences a reduction in pressure, which can be measured. By calculating the difference in pressure before and after the orifice, the flow rate can be determined. This method is widely used due to its simplicity, reliability, and low cost.

In the context of flow measurement, the orifice meter is particularly effective because it can provide accurate readings for a variety of fluids under diverse conditions. The size and shape of the orifice can be designed to optimize the flow characteristics for specific applications, making it a versatile choice in various industrial processes.

While other devices such as Venturi meters, magnetic flow meters, and rotometers also measure flow, they do so through different mechanisms and designs. The Venturi meter uses a converging section to create a pressure drop, magnetic flow meters utilize electromagnetic induction, and rotometers measure flow by observing the rotation of a float within a tapered tube. Each of these devices has its own advantages and specific application areas, making them distinct from the orifice meter.