This newly expanded edition shows plant engineers and maintenance personnel how to systematically analyze and troubleshoot machinery distress and component problems. You will find complete coverage of gears, rolling-element bearings, sliding bearings, bolting, couplings, and mechanical seals, with more on pumps, compressors, electric motors, steam turbines, and similar equipment.
Eliminate just the symptoms, and not the root cause, and you will again face equipment downtime and component failure. This book documents and analyzes actual failure events to give you the know-how to discover not just the problem, but its underlying cause.
A new chapter examines root cause analysis and shows how to pursue the cause-and-effect relationship. Details on the practical aspects of metallurgical failure analysis have been added and the chapter on vibration analysis has been thoroughly updated.
Reliability professionals, process engineers, plant operators, and repair and maintenance personnel will value this new edition as the standard authority on the subject.
Review
A revised and updated guide (1st ed., 1983) that shows plant engineers and supervisors how to systematically analyze and troubleshoot machinery component distress with field-proven techniques. It covers gears, rolling-element bearings, sliding bearings, bolting, couplings, mechanical seals, etc. on pumps, compressors, electric motors, steam turbines, and similar equipment. New to this edition are descriptions of enhanced methods of metallurgical failure analysis, approaches to coupling distress investigations, and updated procedures for lube-oil management in process plants. Annotation copyright Book News, Inc. Portland, Or. --This review refers to an out of print or unavailable edition of this title.
Excerpt
"A rather large number of factors influences lubricating oil
degradation and, consequently, pump bearing life. If your
centrifugal pumps are equipped with rolling element bearings,
there is little doubt that medium viscosity turbine oils
(ISO Grade 68) will perform better than the lighter oils
originally specified by many pump manufacturers. But, by far,
the most frequent cause of lube-oil-related failure incidents
is water and dirt contamination. With only 20 ppm water in pure
mineral oil, bearing surface and rolling element fatigue life is
reduced by an incredible 48 percent. Although the fatigue life
reduction is less pronounced with inhibited lubricants, there
are always compelling reasons to exclude dirt and water from
pump bearing housings. Lip seals are a poor choice for
centrifugal pump installations demanding high reliability. Face
seals represent superior, "hermetic" sealing and should be given
serious consideration.
"On a related subject, have you explained to your operators and
maintenance personnel that a full-bottle oiler is no guarantee
of adequate lubrication? The height of the beveled tube
determines the level of oil in the bearing housing, and all too
often there will be costly misunderstandings. However, there are
at least two considerably more elusive problems involving bottle
oilers.
"The first of these is that bottle oilers may malfunction unless
suitably large bearing housing vents are provided. With a
relatively viscous oil and close clearance at the bearing housing
seal, an oil film may exist between seal bore and shaft surface.
Good lube oils have a certain film strength and under certain
operating conditions, this sealing film near the bearing end cap
may break only if the pressure difference bearing housing
interior-to-surrounding atmosphere exceeds 3/8 inch of water
column.
"If now, the bearing housing is exposed to a temperature increase
of a few degrees, the trapped vapors - usually an air-oil mix -
floating above the liquid oil level will expand and the pressure
may rise 1/4 inch of water column. While this would not be
sufficient to rupture the oil film so as to establish equilibrium
between atmosphere and bearing housing interior, the pressure
buildup is nevertheless sufficient to depress the oil level from
its former location near the center of a bearing ball at the 6
o'clock position to a new level now barely touching the extreme
bottom of the lowermost bearing rolling element. At that time, the
bearing will overheat and the lube oil in contact with it will
carbonize. An oil analysis will usually determine that the
resulting blackening of the oil is due to this high temperature
degradation.
"The second of the elusive oil-related problems often causes the
contents of bottle oilers to turn grayish color. This one is
primarily observed on ring-oil lubricated rolling element bearings.
"Suppose you have very precisely aligned the shafts of pump and
driver; nevertheless, shims placed under the equipment feet in
order to achieve this precise alignment caused the shaft system
to slant 0.005" or 0.010" per foot of shaft length. As a
consequence, the brass or bronze oil slinger ring will now
exhibit a strong tendency to run "downhill." Thus bumping into
other pump components thousands of times per day, the slinger
ring gradually degrades and sheds numerous tiny specks of the
alloy material. The specks of metal cause progressive oil
deterioration and, ultimately, bearing distress.
"Pump users may wish to pursue one of two time-tested preventive
measures. First, use properly vented bearing housings or, better
yet, hermetically sealed bearing housings without oiler bottles.
The latter are offered by some pump manufacturers and incorporate
bull's-eye-type sight glasses to ascertain proper oil levels.
"The second preventive measure would take into account the need
for radically improved pump and driver leveling during shaft
alignment or, even more desirable, apply flinger spools. Of
course, oil mist lubrication or direct oil injection into the
bearings would represent an altogether more dependable, long-
term satisfactory lube application method for centrifugal pumps."
Table of Contents
The Failure
Analysis and Troubleshooting System
Troubleshooting as an Extension of Failure Analysis.
Causes of Machinery Failures. Root Causes of Machinery Failure.
References.
Machinery
Component Failure Analysis
Bearings in Distress. Rolling-Element Bearing Failures
and Their Causes. Patterns of Load Paths and Their Meaning in Bearing
Damage. Troubleshooting Bearings. Journal and Tilt-Pad Thrust Bearings.
Gear Failure Analysis. Preliminary Considerations. Analytical Evaluation
of Gear Theoretical Capability. Metallurgical Evaluation. General
Mechanical Design. Lubrication. Defects Induced by Other Train Components.
Wear. Scoring. Surface Fatigue. Failures from the Manufacturing
Process. Breakage. Lubricated Flexible-Coupling Failure Analysis.
Gear-Coupling Failure Analysis. Gear-Coupling Failure Mechanisms.
Determining the Cause of Mechanical Seal Distress. Troubleshooting
and Seal-Failure Analysis. Summary of Mechanical Seal Failure Analysis.
Lubricant Considerations. Lubrication Failure Analysis. Why Lube
Oil Should Be Purified. Six Lube-Oil Analyses Are Required. Periodic
Sampling and Conditioning Routines Imple-mented. Calculated Benefit-to-Cost
Ratio. Wear-Particle Analy-sis Grease Failure Analysis. Magnetism
in Turbomachinery. References.
Machinery Troubleshooting
The Matrix Approach to Machinery Troubleshooting.
Troubleshooting Pumps. Troubleshooting Centrifugal Compressors,
Blowers, and Fans. Troubleshooting Reciprocating Compressors. Troubleshooting
Engines. Troubleshooting Steam Turbines. Troubleshooting Gas Turbines.
Troubleshooting Electric Motors. Troubleshooting the Process. References.
Vibration
Analysis
Interpretation of Collected Data. Aerodynamic Flow-Induced
Vibrations. Establishing Safe Operating Limits for Machinery. Appendix:
Glossary of Vibration Terms. Formulas. References.
Generalized
Machinery Problem-Solving Sequence
Situation Analysis. Cause Analysis. Action Planning
and Generation. Decision Making. Planning for Change. References.
Statistical
Approaches in Machinery Problem Solving
Machinery Failure Modes and Maintenance Strategies.
Machinery Maintenance Strategies. Hazard Plotting for Incomplete
Failure Data. Method to Identify Bad Repairs from Bad Designs. References.
Sneak Analysis
Sneak Analysis Use. Sneak Circuits and Their Analysis.
Historical Development of SCA. Topological Techniques. Cost, Schedule,
and Security Factors. Summary of Sneak Analysis. Conclusion. References.
Formalized
Failure Reporting as a Teaching Tool
The Case of the High-Speed. Low-Flow Pump Failure.
The Case of the Tar Product Pump Failure.
The "Seven-Cause
Category Approach" to Root-Cause Failure Analysis
Checklist Approaches Generally Available. Failure
Statistics Can Be Helpful. Systematic Approaches Always Valuable.
Faulty Design Causes Premature Bearing Failures. Fabrication and
Processing Errors Can Prove Costly. Operations Errors Can Cause
Frequent Bearing Failures. Maintenance Omissions Can Cause Loss
of Life. Awareness of Off-Design and Unintended Service Conditions
Needed to Prevent Failures. Making the Case for Failure Prevention
Ahead of Failure Analysis. References.
Cause Analysis
by Pursuing the Cause-and-Effect Relationship
Two Types of Problems. The Cause-and-Effect Principle.
Effective Solutions. Creative Solutions. Success Story.
Knowledge-Based
Systems for Machinery
Failure Diagnosis Examples of Knowledge-Based Systems.
Identification and Selection of Knowledge-Based System Applications.
Project Implementation. Expert-System Questionnaire. References.
Training and
Organizing for Successful Failure Analysis and Troubleshooting
Specialist Training Should Be Considered. Professional
Growth: The Next Step. Organizing for Failure Analysis and Troubleshoot-ing.
Definition of Approach and Goals. Action Steps Outlined. Development
of Checklists and Procedures. Program Results. Postscript: How to
Find a Reliability Professional. References.
