Which of the following best describes a lantern ring?

• A. Metal ring for lowering an explosive gas detector candle into manholes and wet wells
• B. Shaft coupling that has been completely worn through in spots or that has daylighted
• C. Spacer ring in a pump packing gland to improve seat water distribution
• D. Type of coupling for joining pipes that will not be covered or put in the dark for at least 24 hours

Answer: (C)

A lantern ring is a spacer built into a pump stuffing box that allows cooling or flushing water to reach the packing area. This water flow helps distribute water around the seal (the seat) evenly, cooling the packing and carrying away debris. That distribution of seat water around the packing is the key function, which is what this option describes.

The other choices describe unrelated items: one is about a tool to lower a gas detector candle into manholes, another is a shaft coupling that’s worn through, and the last is a type of pipe joining method that wouldn’t be kept in the dark. None of these involve a spacer ring inside a packing gland for seat-water distribution.