The branch connection to the desuperheater uses which valve to prevent reverse flow?

The branch connection to the desuperheater uses which valve to prevent reverse flow?

• A. Stop valve.
• B. Stop-check valve.
• C. Gate valve.
• D. Globe valve.

Answer: (B)

Preventing reverse flow in a desuperheater branch requires a valve that both shuts off flow and blocks backflow automatically. The desuperheater injects water into steam, and if pressure on the downstream side is higher or the injection stops, you don’t want steam or condensate pushing back into the supply line. A stop-check valve provides that dual function: it opens for normal forward flow, but its built-in check mechanism closes if reverse flow tendency is detected, protecting the upstream line and equipment. It can also be isolated for maintenance with the stop feature. The other valves aren’t designed to handle backflow automatically: a stop valve alone can stop flow only when closed, and gate or globe valves serve primarily as shutoff or throttling devices without a true backflow-preventing action.

Preventing reverse flow in a desuperheater branch requires a valve that both shuts off flow and blocks backflow automatically. The desuperheater injects water into steam, and if pressure on the downstream side is higher or the injection stops, you don’t want steam or condensate pushing back into the supply line. A stop-check valve provides that dual function: it opens for normal forward flow, but its built-in check mechanism closes if reverse flow tendency is detected, protecting the upstream line and equipment. It can also be isolated for maintenance with the stop feature. The other valves aren’t designed to handle backflow automatically: a stop valve alone can stop flow only when closed, and gate or globe valves serve primarily as shutoff or throttling devices without a true backflow-preventing action.