Loading documents preview...
FERROGRAPHY Condition Monitoring through Oil Analysis
Condition Monitoring Through Oil Analysis • Monitoring the Condition Of the Oil • Monitoring the Debris in the Oil
Oil Analysis • • • • • • • • •
Viscosity Water by Karl Fischer TAN/TBN Titration FTIR Spectroscopy (Infrared) Flash Point Fire Point Wear metals in ppm Particle Counting Chip detection Etc.,
Used Oil Analysis Vs Ferrography • Used Oil Analysis
Oil Condition
• Ferrography
Machine Condition
Effective Range of Particle Detection
NORMAL WEAR REGION
ABNORMAL WEAR REGION
Wear Debris Ferrography Spectrometry 0.1
1
5
10
100
Wear Particle Size (Micrometers m)
1000
FERROGRAPHY WEAR PARTICLE ANALYSIS
The Lab
FERROGRAPHY-HISTORY • Developed in 1971 • Used to monitor U.S military aircraft,submarines etc.,
FERROGRAPHY • NON INTRUSIVE EXAMINATION OF THE OIL WETTED PARTS • PARTICLES CONTAINED IN THE OIL CARRY DETAILED INFORMATION ABOUT THE CONDITION OF THE MACHINE • PARTICLE CHARECTERISTICS ARE SPECIFIC TO OPERATING WEAR MODES
The Concept Every lubricated wear surface generates particles There is a gradual build up of small particles in a normal system When abnormal wear begins, there is no sharp instantaneous increase in the concentration of small particles present in the system Large particles, however, reach a dynamic equilibrium in a normal system (filtration) When abnormal wear begins, there is a dramatic increase in the concentration of large particles Therefore, detection, measurement and analysis of these large wear particles can provide early and accurate information about the condition of the machine
Wear Particle Analysis Trending
ANALYSIS • QUANTITATIVE • QUALITATIVE
QUANTITATIVE • • • • •
DIRECT READING FERROGRAPHY DR III DL > 5 microns DS < 5 microns DL+DS = WPC (Wear Particle Concentration)
DR-5 Direct Reading Ferrograph • Separates wear debris from lubricant according to size • Trends small & large particles for wear condition • DL & DS, 5 micron breakpoint
QUALITATIVE • • • •
ANALYTICAL FERROGRAPHY FM III FERROSCOPE PASSPORT- DATA MANAGEMENT
FM-IIId Ferrogram Maker • Makes slides to examine with Ferroscope • Particle sorting by size, shape, concentration & composition • Ferrous particles align with magnetic lines of flux • Analyzed to determine root cause of the particle formation
Ferrogram principle Non-Ferrous Debris
Distance in mm
Flux Lines w/Debris N Magnet Pole
EXIT END
Non-Magnetic Barrier, 2.5mm S Magnet Pole
Non-Wetting Barrier 0.3x60mm Glass Substrate
< 0.5 µ Ferrous Particles
<5µ >5µ Ferrous Particles
ENTRY POINT
Particle Classification • Ferrous Low alloy,Medium alloy and High alloy
• Non-Ferrous Copper Alloys, Aluminum alloys, Babbitt Metals
• Contaminants Dust, Dirt, External Process, Manufacturing Debris, Filter Material, Friction Polymers,
Ferroscope 5 • Multiple Objectives • Two light sources • Video Camera for computer screen captures • Filters to identify Sand/dirt and red oxides
Trending Wear Particle Concentrations WPC=10
WPC=50 WPC=100 WPC=500
WPC=1000
Particles Identified in Ferrography
Normal Rubbing Wear Description - Flat platelets - Less than 15 microns in major dimension
Causes - Normal machine wear
Severe Sliding wear Description - Flat elongated particles with striations - Greater than 20 microns in major dimension
Causes - Excessive load - Excessive speed on sliding surface
Gear wear Description - Flat striated particles
Causes - Fatigue - Scuffing - Scoring of gear teeth
Bearing wear Description - Laminar platelets
Causes - Rolling contact failure
Spheres Description - Small spheres - Less than 5 microns in diameter
Causes - Early warning of rolling element bearing failure
Pb/Sn BABBITT
Cutting wear Description - Long, curled strips
Causes - Misalignment - Abrasive contaminant in the lubricant
Cutting Wear
Black Oxides Description - Black particles aligned in magnetic field
Causes - Insufficient lubrication
Red Oxides
Corrosive Wear Description - Heavy concentration of fine particles at exit of ferrogram
Causes - Oil additive depletion
Cast Iron
Copper Alloy Particle
Aluminum Alloy Particle
Pb/Sn BABBITT
Fibers
Sand/Dirt
Friction Polymer
Evaluation • • • • • •
Wear particle concentration(WPC) Size of the particles Shape of the particles Surface texture Concentration and orientation Morphology
Severity Ratings 0 NORMAL
45
78
10
MARGINAL CRITICAL
Ratings are purely subjective based on Machine being monitored Morphology of particles WPC
Case Study 1 Facility : Power Plant Equipment : ID Fan Fluid Coupling • In Sample dated 16/9/01 Cu alloy particles of size ranging up to 400 microns were observed and inspection of the internals was recommended after analyzing another sample.Samples dated 11/10/01 and 22/12 /01 have shown bearing wear particles along with Copper alloy particles. • Inspection was carried out on5/01/02.It was found that output shaft bearing cage was completely worn out.Coupling was changed. • Savings : 1.Savings on loss of generation due to downtime itself was around 9 million units amounting to 90 lakhs approx. 2.Secondary damage to fan and coupling avoided.
Acrobat Document
Acrobat Document
Case study 2 Facility : Power Plant Equipment : Cooling tower fan Gear box. • Sample dated 06.09.02,report rated critical due to the presence of abnormal bearing wear(fatigue) particles and advised inspection can be carried out after analyzing another sample. • Based on this report Inspection was carrried out severe fatigue wear found on the outer & inner race and all rollers of output shaft bearing.
Acrobat Document
APPLICATION • • • • • • • • •
Bearings Gear Boxes Pumps Turbines Engines Compressors Earth Moving Equipment Tool room equipment Very Large ,Very Slow speed M/c
• • • • • • • • • •
Steel Refinery Cement Fertilizer Paper Power Plants Mining & Quarrying Tool Room Railways/Locos,Road Ships Etc.,
BENEFITS • Ferrography identifies Wear Particles as well as Contamination • Hence, Life extension benefits of Proactive Maintenance(controlling contamination etc.,) and early warning benefits of Predictive Maintenance can be simultaneously achieved.
CONCLUSION • Many New Technologies are being invented and applied for Condition Monitoring of Equipments • None is all inclusive,yet each has a valuable contribution to play. • Combination Of Technologies helps in finding a meaningful solution. • We look for the benefits of the technology without fulfilling the requirements.
SAMPLING TECHNIQUES
GARBAGE IN,GARBAGE OUT An analytical report,no matter how brilliantly written,is worse than meaningless if the samples taken are not representative of the system being monitored
SELECTION OF SAMPLING POINT • Sample tap in return line of the last lubricated component. • Sample(valve) at about 2/3rd distance from top in case of reservoirs,tanks. • In circulating portion of the reservoir at entry end near mid-height of the reservoir.
Sampling Point Selection COMPONENT
. . SAMPLING VALVE
FILTER
CIRCULATING LUBRICANT
PUMP
SAMPLE BOTTLE
RESERVOIR
SAMPLING CAUTION • Do not sample more than 15 minutes after shut down. • Do not sample down stream of Filter. • Do not sample at dead areas of the system. • Do not sample from top or bottom of the reservoir.
Sampling from Tanks when there is no Provision From Return Line
Sampling from Sump
THANK YOU