Which type of valve is generally used for isolating sections of a sewer system?

The gate valve is generally used for isolating sections of a sewer system due to its design that allows for a full flow path when opened. This type of valve provides minimal resistance to flow, which is essential in a sewer application where reducing pressure loss is critical. When the gate valve is fully opened, it has a low head loss, allowing for efficient operation.

In the context of maintenance or emergencies, gate valves can be closed completely, effectively isolating a section of the sewer system for repairs without affecting the entire network. Their ability to provide a straight-line flow path with minimal turbulence makes them ideal for this purpose.

Other valve types, while functional in specific scenarios, do not match the effectiveness of gate valves for isolation. For instance, check valves are primarily designed to prevent backflow and do not serve the purpose of isolation. Pressure relief valves are used to manage pressure within a system and are not meant for isolation. Ball valves, while also capable of providing complete shut-off and are used in various piping systems, may not always be the best choice in larger sewer applications due to their design and the specific flow characteristics needed in sewer systems. Gate valves remain the standard for isolating sections effectively and efficiently.