What type of valve is typically used for on/off control in steam systems?

Gate valves are commonly used for on/off control in steam systems due to their design, which allows for minimum pressure drop and low frictional loss when fully opened. The gate valve operates by lifting a gate out of the path of the fluid, enabling full flow without any turbulence. This makes it ideal for applications where the valve will either be completely open or completely closed, ensuring optimal flow control without altering pressure or flow characteristics in the system.

When it comes to steam systems, the ability to quickly and effectively shut off flow is crucial for safety and operational efficiency. The gate valve functions reliably in this capacity and is favored in situations where fluid must be quickly isolated or where there’s a need for a straight-through, unobstructed flow path.

In contrast, check valves typically allow flow only in one direction and are primarily used for preventing backflow. Globe valves, while versatile and better for throttling control, introduce more resistance and are not suited for situations requiring complete shutoff. Pressure relief valves are safety devices meant to protect against overpressure conditions, and they function differently from service valves like those used for manual control.