Which valve type has the lowest pressure drop during operation?

The ball valve has the lowest pressure drop during operation compared to other valve types. This is due to its design, which features a hollow, spherical closure element that rotates to control the flow. When fully open, the ball allows fluid to flow straight through the valve with minimal turbulence and resistance, causing very little pressure drop.

In contrast, globe valves have a more complex flow path that creates significant turbulence, leading to higher pressure drops. Butterfly valves, while also offering lower pressure drops than globe valves, still introduce some flow obstruction due to the position of the disc within the pipeline. Gate valves, designed to be fully opened or closed, can cause some flow restriction when they are not fully opened, increasing the pressure drop across the valve.

Ultimately, the ball valve's streamlined design when opened fully provides the best flow characteristics, making it the most efficient option in terms of minimizing pressure drop during operation.