A stuffing box type of shaft seal on a centrifugal pump needs periodic maintenance. If the seal is found to be leaking excessively, the technician should

• A. tighten the packing gland and/or replace the packing.
• B. Replace the carbon washer and/or tension the spring.
• C. Replace the entire seal as this is cheaper than repairing a leaking seal.
• D. Replace the pump, as the seal is an integral part of the pump and not easily replaced or repaired.

Answer: (A)

In a stuffing box, the seal is formed by packing material wrapped around the shaft and held in place by a packing gland. Proper leakage control comes from compressing that packing enough to seal while avoiding excessive friction and heat. When leakage is excessive, the technician should first tighten the packing gland to increase the compression of the packing. If leakage persists after a careful, gradual tightening, the packing itself may be worn or damaged and should be replaced. This keeps the maintenance focused on the packing around the shaft, which is the part involved in a stuffing box seal.

Replacing carbon washers or tensioning a spring relates to other seal types, not a stuffing box, so they don’t address the basic issue here. Replacing the entire seal or the pump is unnecessary unless there is irreparable damage; the standard, first-step repair is to adjust or replace the packing.