What is the advantage of using a venturi tube for flow measurement compared to an orifice plate?

The advantage of using a venturi tube for flow measurement compared to an orifice plate lies primarily in its ability to produce less pressure drop across the device. This characteristic is crucial in applications where maintaining the pressure is important for efficient system operation.

A venturi tube is designed with a gradually converging section that leads to a throat and then a gradually diverging section. This design allows fluid to accelerate and then decelerate smoothly, resulting in a relatively lower pressure drop when compared to an orifice plate, which has a sharp edge that causes a more abrupt change in flow direction. The gradual transition in a venturi helps to minimize energy losses, making it more efficient in terms of pressure retention.

In addition to being advantageous for maintaining system pressure, the lower pressure drop associated with venturi tubes can also lead to lower energy costs, decreased wear and tear on pumps, and better overall system performance. This is particularly beneficial in applications involving large flow rates, where maintaining an optimal operating pressure is critical.