Install packing on a centrifugal pump so the lantern ring is:

The correct positioning for the lantern ring in a centrifugal pump is to have it flush against the packing gland. This placement is crucial because the lantern ring serves as a conduit for the seal water or cooling liquid to flow into the stuffing box. When it is placed against the packing gland, it ensures that the flow of fluid can evenly distribute around the packing material, helping to maintain appropriate operating temperatures and prolong the life of the packing itself by preventing overheating due to friction.

Placing the lantern ring in other positions could hinder its functionality. For instance, if it is not aligned with the cooling liquid opening, it would not facilitate proper cooling and sealing of the pump, possibly leading to premature packing failure. Similarly, positioning it flush against the wear ring or at full depth might restrict the necessary flow for effective cooling, leading to reduced efficiency and increased wear on the packing material. Thus, ensuring that the lantern ring is flush against the packing gland is essential for maintaining optimum performance and longevity of the centrifugal pump.