Lubricant Monitoring-ferrography

1. MAINTENANCE ENGINEERING
MODULE IV
PREPARED BY
DHANESH S
ASSISTANT PROFESSOR
AHALIA SCHOOL OF ENGINEERING AND TECHNOLOGY

2. LUBRICANT MONITORING
• Lubricant oil required to perform a number of functions such as to reduce
friction, to cool components and to clean load-bearing surfaces
• With passage of time, oil may degrade, losing its lubrication properties due to
chemical breakdowns and becoming contaminated by ingress of collates, fuels
and other lubricants
• Also there may be built-up of particles in systems caused by wear or
generation of soot

3. LUBRICANT MONITORING
• Tests/analysis of lubricant can be grouped into three categories:
• Fluid Properties Analysis-information on a lubricant’s physical and chemical
properties such as viscosity, acid number, additives
• Fluid Contamination Analysis-Presence of contaminants such as dirt, glycol, ,soot,
fuel, water etc in oil
• Fluid Wear Debris Analysis- Concentration and characterization of wear metals
and other contaminants, suspended in used oil, mainly from machine components
through which oil interfaces and generates some wear metals and wear particles
and not about oil itself. Also called machine health analysis
• Fluid Chemical Properties

4. LUBRICANT MONITORING
• Fluid debris analysis is used for equipment health monitoring.
• Mainly works on contaminants generated due to interaction between various
components/parts of machine and carried away by lubricant to sumps etc
• Also called as contaminant monitoring or wear debris analysis or wear-
particle analysis

5. LUBRICANT MONITORING
• Components and Techniques of Lubricant Monitoring:
• Sources of wear debris
• Distinction between amount, size, shape and chemical breakdown
• Numerical method monitoring
• Direct reader ferrography
• Visual method monitoring
• Filter debris analysis
• Scanning electron microscope
• Magnetic plugs
• Used engine oil test and other oil test kits
• Lab tests
• Lubricant contamination control

6. LUBRICANT MONITORING
• Types and Sources of Contaminants:
• Can be classified as following
• Rubbing wear particles-normal wear, small flakes of metal etc
• Fatigue chunks-sub surface stressing in gears or shafts, large chunks of metal etc
• Sliding wear particles-scuffing wear, metal to metal contact with no lubricant film, gear teeth
pistons, hydraulics, loose bearings, parallel striations on surface etc
• Cutting wear- abrasive contact between two surfaces, 2 body wear softer metal is cut,3 body
wear , curls of metal like lathe swarf etc
• Laminar wear-sub surface stressing in rolling element bearings, reworked wear particles, flat,
think flakes of metal
• Oxides and rust etc

7. LUBRICANT MONITORING
• Contaminants encountered in industries are grouped as:
• Built-in Contamination-include built-in manufacturing debris, permanent debris and other
damage which occur during run-in etc
• Internally Generated Contamination-wear debris from gears, bearings, splines or other
components resulting from micropitting, macropitting, adhesion,abrasion or fretting
corrosion
• Ingressed Contamination-include moisture, acids or other fluids and different kind of
fumes and gases from atmosphere or nearby industrial environment etc
• Contamination Added During Maintenance- due to improper maintenance cleaning,
protecting and unclean environment etc
• Contaminants due to accidents and malicious acts
• Biological Contamination- bacterias, microbes, algae, fungi and other mirco-organism in
water, hydraulic and cutting fluids and other industrial fluids

8. LUBRICANT MONITORING
• Magnetic Plugs:
• Simple magnetic probes/plugs positioned in lubrication systems for maximum catch
efficiency of wear debris and other metallic particles form oil
• Usually fitted at bottom portion of sump, reservoir, bigger pumps, gearboxes and
centrifugal compressor castings so that these can be removed periodically along with
collected metallic debris and replaced by spare plug or same plug after carefully removing
all debris and cleaning
• Debris collected are quantified and examined visually or by other means
• Also helps in cleaning the oil
• Also work are drain plug

9. LUBRICANT MONITORING
• Filter Debris Analysis and Fillergrams:
• Filters are commonly used in lubricating and hydraulic systems to keep fluid clean
• Filter captures the particles generated since last filter change and leading up to the failure
event or next filter change
• Debris collected in filters is often examined for wear prediction
• Diagnostic filter system-debris is removed from filter element onto an analysis membrane by
back flushing with solvent or solvent-air mixture by ultrasonic removal in a solvent or by
flushing debris off the filter element with a solvent or by other means
• Debris collected on analysis membrane is evaluated for amount , size distribution and
morphology
• Chemical composition determined by spectroscopy or by IR spectroscopy or ferrography etc
• Diagnostic filler system comprised of a diagnostic filter element having a pull out diagnostic
layer and a custom designed contaminant analyzer

10. LUBRICANT MONITORING
• Advantages of employing filter debris analysis-
• Full flow nature of filter element allows all the fluid in system to pass through filter
element
• Coherent surface for capturing fluid system debris efficiently , results in a high
concentration of debris compared to debris in fluid or in magnetic plugs/chips detectors
• Filtergrams are images of debris segregation and concentration
• Prepared by filtering a sample of oil through a 3 to 8mm cellulose nitrate membrane
filter
• Drop of clarifying solution is added and slit is baked in an oven
• Similar to ferrograms when used for ferrous materials

11. LUBRICANT MONITORING
• Filtergram analysis is microscopic inspection of contaminants and wear debris in a
fluid sample of filter medium
• For getting filtergram, approximately 10cm2 of filter pleat is collected as a sample
• Sample is washed in a solvent and filtered through a fine cellulose nitrate membrane
filter to capture any particular matter for examination under a high powered
microscope
• Particle size , wear factor and identification are reported in graphs and include two
scaled photographs highlighting critical points in a sample
• Filtergram report include a breakdown of the percentage of particulate matter under
classification of size, metallurgy and wear factor

12. FERROGRAPHY
• Analytical method of assessing machine condition by quantifying and examining wear
particles suspended in lubricant of hydraulic fluid
• Uses a strong magnetic field to separate particles according to their size
• Contaminants of size 0.1 to 500 micron range can be detected
• Provides a comprehensive non-intrusive evaluation of health of lubricated
components while equipment is in running state
• Wear debris present in lubricant sample are precipitated on a glass substrate which
can be views through a powerful bichromatic microscope
• Major findings from ferrography-wear mode, rate, severity and location
• Identified wear modes include abrasion, impact, fatigue, erosion , corrosion, scuffing
etc

13. FERROGRAPHY
• Glass substrate or ferrogram analysis is one common method of particle
identification
• Combination of incline, sample preparation, and a magnetic filed ensure that
all particles present in lubricant sample are deposited on substrate for
examination
• Ferrography is generally of two types-Direct reading and Analytical

14. FERROGRAPHY
• Direct Read Ferrography(DRF):
• Quantitative analysis of ferrous particles present in used oil
• Provides an index of large ferrous particles to small ferrous particles
• Can identify ferrous wear occurring within a limit
• Sample to be suitably diluted
• Wear Particle Concentration(WPC)=DL+DS
• Percentage of large particles(PLP)=((DL-DS))/WPC
• WPC-indicative of rate of wear and is compared to industry averages for specific type of
equipment being tested

15. FERROGRAPHY
• Analytical Ferrography(AF):
• Can predict potential equipment failures or be an effective tool in determining root cause
of failure
• Qualitative rather than quantitative analysis that provides digital imagery of actual
particles present
• Utilizes microscopic analysis to identify composition of material present
• Will differentiate type of material contained within the sample and determine wearing
component from which it was generated
• Powerful magnet trap the ferrous particles which are then places on slides for
microscopic analysis

16. FERROGRAPHY
• RPD Rotary Ferrograph:
• Combines magnetic and centrifugal separation
• Faster than both AF and DRF techniques and presents a sample ready for
microscopy in few minutes
• Does no require sample to be diluted and does not suffer from interference due to
carbonaceous material in sample
• Offers a rapid and simple method of debris seperation

17. SPECTROSCOPIC OIL ANALYSIS PROGRAM(SOAP)
• Procedure for extracting fluid samples from operating systems and analysing
them spectroscopically to determine the concentration of key elements
represented in entrained fluid contaminant
• Molecular spectroscopy uses principles of chemical physics to determine molecule
concentrations
• Here measurements are directly, additive decomposition, like hydrolysis of ZDDP
• Many molecular spectroscopic tools are well suited for determining
concentrations of organic molecules
• Spectroscopy is most widely applied technique for debris monitoring

18. SPECTROSCOPIC OIL ANALYSIS PROGRAM(SOAP)
• Provides a quantitative, multi-elemental analysis of wear debris in lubricating
oil
• Wear metals such as iron, aluminium, chromimum, copper, tin, lead, silver,
titanium and nickel are detectable
• Lubricant additives such as calcium, barium, zinc, phosphorus etc are also
detectable
• Certain contaminants like silicon, sodium, potassium also detected

19. SPECTROSCOPIC OIL ANALYSIS PROGRAM(SOAP)
Typical Machinery Problems Indicated by SOAP

20. COMPARISON OF WEAR DEBRIS ANALYSIS
TECHNIQUES