Page 262 - Intro Predictive Maintenance

Process Parameters 253

Table 10–19 Common Failure Modes of Packing and Mechanical Seals

THE PROBLEM

Excessive Leakage Continuous Stream of Liquid No Leakage Shaft Hard to Turn Shaft Damage Under Packing Frequent Replacement Required Bellows Spring Failure Seal Face Failure

THE CAUSES
Cut Ends of Packing Not Staggered
Nonrotating Not Packed Properly
Line Pressure Too High

Packed Box Too Loose
Packed Box Packing Gland Too Loose

Packing Gland Too Tight

Cut End of Packing Not Staggered
Line Pressure Too High

Rotating Mechanical Damage (Seals, Seat)

Noncompatible Packing

Packing Gland Too Loose
Packing Gland Too Tight
Flush Flow/Pressure Too Low
Flush Pressure Too High
Internal Flush Induced Misalignment

Improperly Installed

Internal Flush Line Plugged

Line Pressure Too High
Mechanical Seal Physical Shaft Misalignment

Seal Not Compatible with Application

Contamination in Flush Liquid

External Flush Line Plugged
External Flush Flush Pressure Too High
Flush Flow/Pressure Too Low

Improperly Installed

Induced Misalignment

Line Pressure Too High

Physical Shaft Misalignment

Seal Not Compatible with Application
Source: Integrated Systems, Inc.