AWWA ABC Water Distribution Grades 1 and 2 Practice Exam 2026 – Comprehensive All-in-One Guide for Exam Success!

The packing gland is the component located at the top of a stuffing box. Its primary function is to compress a sealing material (packing) around a rotating or reciprocating shaft, preventing leaks of fluid along the shaft. The packing gland achieves this by exerting pressure on the packing material, ensuring a tight seal while allowing for the necessary movement of the shaft. This design is critical in various applications within water distribution systems, ensuring that pumps and valves operate effectively and without unnecessary fluid loss.

In contrast, a stuffing nut, while it might be involved in the assembly of the stuffing box, is not typically positioned at the top. A backing ring is used within the stuffing box assembly to support the packing and does not sit at the uppermost position. Finally, a flange serves a different function entirely, as it is a component used to connect pipes or fittings and is not directly associated with the stuffing box mechanism.