Question 213Steam Plants - Assistant Engineer

The correct answer is B) fire-tubes and stay-tubes. In a fire-tube auxiliary boiler, the tube sheets are the large circular plates that the fire-tubes and stay-tubes are connected to. The fire-tubes allow the hot gases from the fire to pass through the boiler, while the stay-tubes help to support and brace the tube sheets against the internal pressure of the boiler. This connection of the tube sheets to the fire-tubes and stay-tubes is the normal method used in the construction of fire-tube boilers. The other answer choices are incorrect because: A) girder stays are not used to connect the tube sheets, C) the external boiler plating is not directly connected to the tube sheets, and D) the tube sheets do not have separate crown sheets in a fire-tube boiler design.