When fully opened, which type of valve is known to have the highest head loss?

When fully opened, a globe valve is known to have the highest head loss due to its design and internal flow characteristics. The globe valve features a spherical body and a flow path that involves multiple changes in direction. This design causes the fluid to encounter significant resistance as it flows through the valve. The flow passage is constricted and creates turbulence, resulting in energy loss—manifested as head loss—when water moves through it.

In contrast, other types of valves like ball valves, gate valves, and butterfly valves are designed for lower flow resistance. Ball valves have a spherical plug that allows for a straight-through flow path when opened, minimizing turbulence. Gate valves allow flow across a straight line and provide minimal obstruction when fully open, leading to very low head loss. Butterfly valves also provide relatively low head loss because of their disk-shaped closure element that can be positioned parallel to the flow, allowing for smoother passage of fluid.

Understanding the hydraulic characteristics of different valves is essential for effective water distribution system design and operation, particularly when considering factors such as energy efficiency and pressure loss in the system.