Which valve offers the least amount of restriction?

The gate valve is designed to provide minimal resistance to fluid flow when it is fully open, as the gate itself is completely out of the path of the fluid. This design allows for a straight-through flow, reducing turbulence and pressure loss significantly compared to other types of valves.

In contrast, globe valves are structured to control flow and throttling, which inherently creates more resistance to flow due to the geometry of the valve. Ball valves, while having a relatively low restriction when fully opened, can still create some flow disturbance due to their ball design. Butterfly valves also provide a decent flow rate, but they can introduce some restriction due to the position of the disc within the pipe flow.

The unique function of the gate valve makes it ideal for applications where a straight flow is necessary, such as in large piping systems. By fully raising the gate, it essentially becomes negligible in the fluid path, offering the least amount of restriction among the options provided. This characteristic is particularly important in applications where efficient flow is critical.