What type of flow measurement device minimizes pressure loss?

The Venturi tube is recognized for its ability to measure flow while minimizing pressure loss. This is achieved through its design, which involves a converging section that narrows the fluid stream, followed by a throat where the flow reaches its maximum velocity, and then a diverging section that allows the fluid to gradually return to its original pipe diameter.

The gradual transition in the Venturi tube helps to reduce turbulence and energy loss, leading to a lower pressure drop compared to more abrupt flow measurement devices. In practical applications, the Venturi effect, which describes the reduction in fluid pressure that occurs when a fluid flows through a constricted section, allows for accurate flow measurement with minimal impact on the overall system.

In contrast, devices like the orifice plate and flow nozzle create more significant pressure drops due to their sharper transitions and restrictions in flow, causing higher energy losses. Rotameters, while effective for certain applications, can also introduce a degree of pressure loss due to their design involving a float that moves in a tapered tube, which may create additional friction and turbulence.

Thus, the Venturi tube stands out as the preferred choice for flow measurement when minimizing pressure loss is a critical consideration.