Packings may fail for a variety of reasons. Besides improper installation, packing failures are often due to worn or faulty equipment, shaft misalignment, uneven take-up on the gland bolts, and other causes.
If you are having troubles, carefully remove and examine the old packing set. DO NOT THORW THE SET AWAY, because it often gives clues as to the condition of the equipment and may be the means of solving the problem. The following clues and possible causes were found by examining sets of packing which failed in service:
Clue 1: Excessive reduction in cross-section of packing directly beneath the rod, shaft, or plunger.
Clue 2: Excessive reduction in the thickness of the packing directly over or on either side of the rod or shaft.
Possible Cause: Rod or plunger out of alignment, and in the case of the rod or shaft, the bearings may be badly worn, causing whipping of the shaft.
Clue 3: A whole ring or part of a ring is missing from set.
Possible Cause: Bottom of stuffing box badly worn, with packing being extruded into the system.
Clue 4: Wear on the outside of one or more rings.
Possible Cause: Rings rotating with shaft or loose in the box. Packing too small.
Clue 5: Axial bulge in one or more rings.
Possible Cause: Adjacent rings cut too short or too long, depending on the style of material used, causing packing under pressure to be deformed.
Clue 6: Packings show tendency to extrude between rod or shaft and the gland follower.
Possible Cause: Excessive gland bolt pressure and/or too much clearance between rod or shaft and the gland follower.
Clue 7: Rings next to gland follower badly damaged, with bottom rings in fair condition.
Possible Cause: Improper installation of packings and excessive gland bolt pressure used.
Clue 8: Wearing surface of rings dried and charred with rest of packings in good condition.
Possible Cause: High temperatures and lack of adequate lubrication.
Clue 9: Innermost ring deteriorated.
Possible Cause: Packing incompatible with fluid handled.
|• Steam or Smoke||• Burned Throat Ring
• Burned Gland Ring
|• Overheated Fluid
|• Cool System
• Change Style
|• Erratic Leakage
• Grit in Leakage
• Grit on Gland
|• Worn Throat Ring
• All Rings Worn
|• Abrasion||• Check Flush
• Install Lantern
• Change Style
|• Steam or Smoke
• Poor Adjustment
• Erratic Leakage
|• Burned Gland Ring
• Rings Feathered Toward Lantern
|• Plugged Flush||• Clean, Realign, Reinstall Lantern Ring|
|• Excess Leakage
• Excess Take-Up
|• Damaged Rings, esp. Throat Rings||• Chemical Attack||• Change Style
• Add Lantern Ring
• Excess Heat
• Shaft Movement
• Difficult Take-Up
|• Eccentric Wear
• Nibbled RIngs
|• Mechanical Problems||• Repair Equipment
• Change Packing Styles
|• Excess Take-Up
• Uncontrollable Leakage
|• Extruded or Feathered Throat Rings||• Excess Throat Clearance||• Repair Throat
• Install Anti-Extrusion Rings