Which valve type is best for a system requiring quick isolation of flow?

A gate valve is the best choice for a system requiring quick isolation of flow due to its design, which allows for minimal resistance to flow and a swift opening and closing action. When fully opened, a gate valve creates a straight passageway for fluids, thus minimizing the pressure drop in the system and facilitating efficient flow control.

In applications where isolation is essential, such as shutting down a line for maintenance or emergency situations, the gate valve's gate mechanism rises completely out of the flow path. This not only provides a tight seal when closed but also allows for rapid flow changes with minimal disruption.

Other types of valves, while suitable for various applications, do not offer the same quick closure and full flow capabilities. For example, a check valve is designed to prevent backflow and does not provide the same level of control or isolation. A globe valve is ideal for throttling flow but is more suited for regulation rather than quick isolation due to its design that typically creates more pressure drop. A butterfly valve can provide rapid opening and closing, but may not offer the same sealing capability as a gate valve, especially under higher pressures.

Hence, the gate valve is the preferred option for applications that necessitate quick and efficient isolation of flow in a system.