Difficulty: Easy
Correct Answer: feed check valve
Explanation:
Introduction / Context:
Proper arrangement of valves in the feedwater line is crucial for safety and operational control. The valve at the boiler inlet must allow feedwater entry while preventing backflow toward the pump and permitting isolation for maintenance.
Given Data / Assumptions:
Concept / Approach:
The feed check valve is a combined stop and non-return valve placed at the boiler inlet. It prevents reverse flow if pump pressure falls and allows the operator to regulate or isolate the feed. In contrast, a blow-off cock is at the bottom for periodic blow-down, and the steam stop valve is on the steam outlet, not the feed line.
Step-by-Step Solution:
Identify function: control + non-return on feed line → feed check valve.Map other devices: blow-off (bottom drain), steam stop (main steam outlet), safety valve (over-pressure relief).Hence, option (b) is correct.
Verification / Alternative check:
Standard boiler codes and textbooks show a check/stop valve at the boiler feed connection, often near the shell or drum nozzle.
Why Other Options Are Wrong:
Common Pitfalls:
Describing any valve near the boiler as a “stop valve.” The feed check valve is specifically on the feedwater line with non-return action.
Final Answer:
feed check valve
Discussion & Comments