Which device serves the same function as packing?

Which device serves the same function as packing?

• A. Mechanical seal
• B. Packing rings
• C. Lantern ring
• D. Gland packing

Answer: (A)

The key idea is that both packing and a mechanical seal are used to stop leakage around a rotating shaft. Packing uses a flexible material placed in a gland around the shaft and tightened to compress and seal. It often leaks a little and requires regular maintenance to keep it tight. A mechanical seal, on the other hand, achieves the same goal with a different mechanism: two smooth sealing faces (one on the shaft, one on the housing) pressed together by springs, with a barrier fluid between them. This design typically provides far tighter leakage control and is better for higher speeds and pressures, making it the device that serves the same purpose as packing. Gland packing is the packing material itself, and packing rings are components of the packing system, not a separate device that replaces packing. A lantern ring is a spacer used to provide lubrication or relieve heat, not a seal by itself. So the mechanical seal is the correct substitute for the sealing function of packing.

The key idea is that both packing and a mechanical seal are used to stop leakage around a rotating shaft. Packing uses a flexible material placed in a gland around the shaft and tightened to compress and seal. It often leaks a little and requires regular maintenance to keep it tight. A mechanical seal, on the other hand, achieves the same goal with a different mechanism: two smooth sealing faces (one on the shaft, one on the housing) pressed together by springs, with a barrier fluid between them. This design typically provides far tighter leakage control and is better for higher speeds and pressures, making it the device that serves the same purpose as packing.

Gland packing is the packing material itself, and packing rings are components of the packing system, not a separate device that replaces packing. A lantern ring is a spacer used to provide lubrication or relieve heat, not a seal by itself. So the mechanical seal is the correct substitute for the sealing function of packing.