Question 422General Subjects - Assistant Engineer

The correct answer is D) Pilot valve and operating rod. In a reciprocating steam pump, the pilot valve and operating rod are used to control the admission of steam to the steam cylinder. The pilot valve regulates the flow of steam into the cylinder, while the operating rod connects the valve to the pump mechanism, allowing the valve to open and close in sync with the pump's motion. This allows the pump to efficiently draw in and expel water. The other options are incorrect because they do not directly control the steam admission. The pump rod is part of the water-side mechanism, the valve operating differential relates to water pressure, and the crosshead arm is part of the mechanical linkage, but none of these directly regulate the steam flow.