Question 124Steam Plants - 1st Asst/Chief

The correct answer is A) Check valve. A check valve is a one-way valve that allows fluid (in this case, water) to flow in only one direction, preventing backflow. In the case of an auxiliary exhaust line, a check valve would be installed to prevent water from the deaerating feed tank from flowing back into the exhaust line if the tank becomes flooded. This protects the engine and exhaust system from potential water damage. The other options are incorrect because: B) A reverse-acting relief valve is used to relieve excess pressure, not prevent backflow; C) Pumps are used to move fluid, not prevent backflow; and D) Exhaust piping alone does not have a mechanism to prevent backflow.