3rd Class Stationary Steam Engineer License Practice Test

The reason an internal overflow or a loop seal is the correct answer lies in its designed function within a deaerator system. A deaerator is used to remove dissolved gases, particularly oxygen, from water, which is essential in steam systems to prevent corrosion.

In order to ensure that condensate does not backtrack into the steam line, a loop seal or internal overflow is implemented. This design allows for the management of condensate flow in a manner that maintains a proper liquid seal, which effectively prevents any backflow of condensate into areas where it shouldn't be, like the steam line. It acts as a barrier, ensuring that the steam and condensate remain separated appropriately, thus maintaining the efficiency of the deaeration process and the overall system integrity.

On the other hand, while an atmospheric vent allows gases to escape—for instance, to help minimize pressure—its purpose does not specifically address the prevention of condensate backflow. A return line is involved in transporting condensate back to a boiler or other system, but lacks the functionality to block backflow into steam lines directly. Similarly, a check valve is typically used to ensure unidirectional flow in pipelines, but in the context of a deaerator, it may not provide the same