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1
Lubrication and Wear(Why, what, when, where, who
& The Need to do Better)
Ken J. Brown, MASc, P.Eng, FSTLE, CLSEco Fluid Center Ltd., Toronto
416 466-3144 www.fluidcenter.com
Why would you be hired?
To provide a function or service to help thecompany make money.
2
What do you offer?
Maybe cheaper, smarter and/or faster.
What can you offer?
Maybe fresh ideas, new procedures and/or afamiliarity with new requirements and/or a
wiliness to adapt plus an ability to use a range ofresources to help provide effective solutions.
3
Job Sectors
Manufacturing
Resources
Service
Sales
Financial
With all of these areas there is usually somethingthat might wear out, could be more efficient,
could last longer, or might work faster.
How will you contribute?
4
The role of good design
Just as a good design takes into account functionas well as safety and sustainability, maintainabilityis extremely important for economic viability.
If you want it done right it has to easy to do it right.
Maintenance Options
Is what is done to keep equipment running. How youdo it can determine whether the facility keeps running.
Types: Fix or repair when;
Failure Maintenance: when it is broken.
Preventative Maintenance: based on time.
Predictive Maintenance: when some conditionindicates it is necessary.
Proactive Maintenance: Taking actions to preventfailures and/or to mitigate the consequences.
5
http://www.maintenanceresources.com/referencelibrary/oilanalysis/oa-what.htm
Tribology
This is from the Greek word tribos. Tribology isthe science and engineering of interactingsurfaces in relative motion.
It includes the study and application of theprinciples of friction, lubrication and wear.
This includes lubricants, but also seals,bearings, wear, metal working, conditionmonitoring and numerous related fields. Plus,ceramics, biomaterials, plastics and frictionmaterials.
6
Why?
With rotating equipment such as pumps, motors,fans, turbines and computer hard drives you havea rotating shaft or disc and stationary supports.
What supports them are bearings that usuallyrequires a lubricant.
The lubricant is what you provide, lubrication iswhat you do to keep the amounts correct andcondition monitoring is what you do to know whatis happening.
Note: For monitoring the purpose is not just for thelube but also the bearings and the health of theequipment.
Brown’s First Law Of Applied Tribology
(Power Generation)
If it's running,It's wearing
If it's not running,It's probably worn!
7
Corollary 1: if not the above then it maybe on standby in case something elsewears out.
Corollary 2: if the equipment is noteconomical to run, this is probablybecause of a loss of efficiency as a resultof wear.
First and Foremost - Viscosity
The viscosity of a fluid is a measure of its
resistance to gradual deformation by stress. For
liquids, it corresponds to the concept of
"thickness".
For example, honey has a much higher viscosity
than water.
Ref: https://en.wikipedia.org/wiki/Viscosity
8
Viscosity cont’d
Viscosity is a property arising from collisions between
neighboring particles in a fluid that are moving at
different velocities.
When the fluid is forced through a tube, the particles
which compose the fluid generally move more quickly
near the tube's center and more slowly near its walls:
therefore some stress, (such as a pressure difference
between the two ends of the tube), is needed to
overcome the friction between particle layers to keep
the fluid moving.
Capillary Viscometer
11
Centipoise
(cP)
Centistokes
(cSt)
Water 1.0 1.002
SAE 10 oil 70 80
Olive oil 100 110
SAE 30 oil 300 350
Glycerin 500 400
SAE 50 oil 800 910
Honey 2,000 1,430
Viscosities of Common Fluids
SAE Automotive Engine Oils
12
SAE Gear Oils
Ref: Petro-Canada 2013 Product Handbook
SAE ViscosityGrade
MaximumTemperature for
Viscosity of150,000 cP, °C
KinematicViscosity at100°C, cStMinimum
70W -55 4.1
75W -40 4.1
80W -26 7.0
85W -12 11.0
SN introduced in October 2010.
Designed to provide improved high temperaturedeposit protection for pistons, more stringent sludgecontrol, and seal compatibility.
API Engine OilService Categories
13
Use what is your manual OR most recent.
Caution. Oils are backwards compatible but not theother way. Some retailers reportedly sell olderversions.
For example API SA contains no additives. Not suitablefor use in most gasoline-powered automotive enginesbuilt after 1930. Use in modern engines may causeunsatisfactory performance or equipment harm.
API Engine Oil Service Categories
Know How to Read Labels
15
Passenger Car Viscosity Grade Use
0W-20, 0W-30, 5W-20, 5W-30, 10W-30,10W-40
-18°C (0°F)
0W-20, 0W-30, 5W-20, 5W-30
Below -18°C (0°F)
0W-20, 0W-30, 5W-20, 5W-30, 10W-30,10W-40, 20W-50
0°C (32°F)
Typical SAE GradesIf the lowestexpected outdoortemperature is;
Note: This is a rough guide from the API.Follow OEM recommendations first.
Typical Motor Oil Additives
Viscosity Index Improvers (VI Improvers)
Dispersants
Detergents
Extreme-pressure/antiwear agents
Antioxidants/Inhibitors
Antifoam agents
Friction modifiers
Metal deactivators
Pour-point depressants
Rust-corrosion inhibitors
https://www.americanchemistry.com/paptg
16
Greases
Oils tend to flow so in cases where you want thelubricants to stay in place but still have somemobility, they use thickeners.
This might be 10-20% of the final productdepending on the thickener used and how stiff youwant the grease. There are a number of thickenersystems including soaps like lithium 12hydroxystearate and non soaps such as clay,polyurea and calcium sulphonate.
17
Grease vs. Oil
Lower limiting speeds
Cooling
Retains wear particles
Sampling
Harder to change
Stays in place
Simpler housings
Can contain solids
Keeps out contaminants
Can be replenished
Grease ConsGrease Pros
Issues
Most electric motors are designed with grease-
lubricated, antifriction, rolling element bearings.
Grease is the lifeblood of these bearings because it
provides an oil film that prevents the harsh metal-
to-metal contact between the rotating element and
races.
BUT!
18
Issues cont’d
Bearing troubles account for 50 to 65 percent of
all electric motor failures, and poor lubrication
practices account for most of these bearing
troubles.
Proper maintenance procedures, planning and
the use of the correct lubricant can increase
productivity by reducing these bearing troubles
and motor failures.
Ref: http://www.machinerylubrication.com/Read/1125/electric-motor-lubrication
Ref: Ward, W., ‘Understanding Calcium Sulfonate Thickeners’,
Machinery Lubrication, Jul 2006
19
NLGI GradeNLGI Grade PenetrationPenetration
000000 445445--475475
0000 400400--430430
00 355355--385385
11 310310--340340
22 265265--295295
33 220220--250250
44 175175--205205
55 130130--160160
66 8585--115115
Note: The grade has nothing to do with quality.
Grease Stiffness Grades
Grease Characteristics
The various greases have characteristics that makethem good for different applications. There is nosuch thing as a universal grease, but there can begeneral purpose greases.
Some desirable characteristics include thefollowing; oxidation resistance, wear protection,corrosion protection, water washout resistance,mechanical stability, resistance to oil separation,high temperature stability, low temperaturemobility, etc.
20
Grease Thickener Characteristics
Ref: PetroCanada 2013 Lubricants Handbook
Grease Mixing
Just like mixing oils can be a bad idea because the
additives could be incompatible, mixing greases has
the added risk of thickener incompatibility. In these
cases the structure can fall apart and it is no longer
a grease or at least softens too much.
Charts are available but if in doubt or for an
important piece of equipment run a compatibility
test in different mixing ratios.
24
The "Right" Stuff
Achieving real benefits requires trueconsideration of the five R’s of lubrication.
right lubricant
right amount
right place
right time
right way
Missing even one can mean failure. Fortunatelyit is generally just as easy to do it right, IF theyknow how.
Ref: ‘Lubricant management for non-circulating sumps’, M.Johnson, TLT, August 2009 pp 16-23
So How Are We Doing?
25
Rolling Element Bearings Lives - Now
New life theory (ISO 281:2007) takes into accountthe viscosity ratio of actual vs. required, type ofbearing, type of loading and cleanliness of the oil.
Lnaa = a1 aISO(C/P)3
Lnaa = adjusted rating life in millions of revolutions
a1 = life adjustment for reliability (i.e. 10% failure)
aISO = life adjustment factor based on new life theory
C = Basic load rating
P = Equivalent dynamic bearing load
Rolling Element Bearings Lives - Now
Life Modification Factor aISO
Among other things considers the influence of:
Fatigue limit of the bearing material by the
fatigue load limit C.
Grade of contaminations by the factor ec.
Lubrication conditions by the viscosity ratio K.
Note: ISO 281:2007 does not cover the influence of wear, corrosion and
electrical erosion on bearing life.
Ref: www.cwbearing.com
26
Rolling Element Bearings
Unfortunately the leading causes of failuresare reported to be improper lubrication andimproper mounting.
‘These are preventable.’
Ref: Hafner, E.R., ‘Proper Lubrication-The Key To Better BearingLife, Part 1: Selecting The Correct Lubricant’, Mech. Eng., pp 32-37, October 1977
In real life it has been reported contaminants cause50% of bearing failures.
Rolling Element Bearings
27
Rolling Element Bearings
Remaining causes are;
Marginal lubrication 30 %Other 17 %Fatigue life 3 %!!!
It was reported that they typically fail at 20%of their catalogue life. Again this is a realwaste.
Ref: NSK as reported in Machinery & Equipment MRO, p13 June 1999
Sources of Problems In Fluid Systems
Ref: Rexroth Oil Contamination Booklet RE 08016 2011
More than 3/4 of all problemscan be traced back to
contaminated oil. Monitoringoil cleanliness is therefore the
most important factor inpreventing system failures.
Monitoring hardware only detects around 20%of all unplanned downtimes.
28
Ref: www.mapro.skf.com/products/
ProactiveProactive –– Do TheyDo TheyHave the Right Tools?Have the Right Tools?
BEARINGS
Ball Bearing Systems 15/13/11
Roller Bearing Systems 16/14/12
Journal Bearings (high speed) 17/15/13 >400 RPM
Journal Bearings (low speed) 18/16/14 <400 RPM
General Industrial Gearboxes 17/15/13
Ref: Eaton Vickers – The Systemic Approach to Contamination Control
Recommended ISO Cleanliness Codes>4 / >6 / >14 microns
31
Ref: www.mapro.skf.com/products/
Proper sized adapter ring, impactssleeves and a soft tipped hammer.
Proactive – Do TheyHave the Right Tools?
Ref: www.mapro.skf.com/products/
Mounting forces must not passthrough the rolling elements
Proactive – Do They Have
the Right Training?
32
Ref: www.pruftechnik.com
Analysis – Where & What?
For monitoring use the same place every time.
Ref: :http://www.reliableplant.com/Read/27324
Approximate BearingFrequencies And Harmonics
Ball Pass Frequency Outer Race (BPFO)= # of rollers x shaft speed x 0.4
Ball Pass Frequency Inner Race (BPFI)= # of rollers x shaft speed x 0.6
Fundamental Train Frequency (FTF)= speed x 0.4
33
Ref: : www.irdmechanalysis.com
Vibration Severity Chart
Ref: : www.irdmechanalysis.com
Vibration Analysis
35
Blotter
Fresh And Three Aged Samples – Color Change
(Left For 5 Hours At Room Temperature)
R/S Rheometer
‘New’ Tests
36
Ruler Test Equipment
‘New’ Tests
Greasing Bearings
Driven EndDriven End
Grease FittingGrease Fitting
Grease PlugGrease Plug
37
Greasing Bearings
Slinger RingSlinger Ring
Grease fittingGrease fitting
Greasing Bearings
Volumetric GreaseVolumetric GreaseRelief PortRelief Port
38
Grease Quantities
For replenishment from the side of a bearing;
Gp = 0.005 D B
For through the bearing outer or inner ring;
Gp = 0.002 D B
Gp = grease quantity, g
D = bearing outside diameter, mm
B = bearing width (thrust bearings use height H), mm
Ref: SKF 2007
Regreasing Amount Example
6316 ball bearing; ID 80, OD 170 mm Width 39 mm
It should get about 0.005 X 170 mm X 39 mm
= 33 g (1.2oz) of new grease.
With the 70MPa (10,000psi) high pressure greaseguns often used, this can require 43 strokes.
39
‘Normal’ Temperature Rise
Ref: Harris, A.F., ‘The Lubrication of Rolling Bearings’, p. 118, ShellInt’l Petroleum Co. Ltd., 1972
Major Causes Of PrematureEngine Bearing Failure
%
Dirt 44.9
Misassembly 13.4
Misalignment 12.7
Insufficient Lubrication 10.8
Overloading 9.5
Corrosion 4.2
Other 4.5
Ref: Clevite AM-208-8
40
Better Seals – What is being used?
Reducing MotorBearing Failures
Shell Canada found that at one of theirrefineries, 91% of the problems with motorswere the bearings.
They were able to achieve a 90% reductionin such failures, mainly by better control oflubrication.
41
Over Greasing
Preventing Over Pressurization
Provides for pressureProvides for pressure--specific shutspecific shut--off (for example, 20 psi).off (for example, 20 psi).At the given shutAt the given shut--off pressure, the grease flow will stop.off pressure, the grease flow will stop.
$0.35 each$0.35 each
42
Thermography
Ref: www.reliableplant.com/Articles/Print/28638
When Is Enough?
Courtesy: EA Grease Caddy
43
What to Test and When
This is best based on your specific
equipment, lubes, skill sets and criticality but
there are still good guidelines readily
available.
Example: ASTM D6244 Standard Practice for
In-Service Monitoring of Lubricating Oil for
Auxiliary Power Plant Equipment
For gear/circulating oils, hydraulic oils, diesel
engine oils, turbine type oils, air compressor
oils, EHC (PO4 esters) EHC Mineral Oils.
What Else?
Examine all removed parts including bearings
and filter elements to refine the maintenance
intervals and to learn what is happening.
For filter elements have both low and high
pressure alarms. A differential pressure that
does not increase is reason to check why.
Periodically look inside reservoirs to check
fluid levels, look for foam, look for deposits
and to look for any plunging returns.
44
Supply line pressure readings for a filter element. Ifworking correctly there should be a rise in pressuredrops, but not too quick. What changed? Gauges?
Fluid? Dirt? You need to know and take action.
A pluggedservovalvescreen can
bring a halt toproduction.
It is only about1” (35 mm)
long.
45
Are we getting better?
Still failures.
Less training and fewer skilled crafts.
More outsourcing.
More ‘penny’ control.
Less innovation.
Less directed training.
Plus, counterfeit part issues.
Wind Turbines – expensive candles
Needs re knowing forces, lube requirements,maintenance and condition monitoring
46
Port Hope – water pumps
What happened, why and what warningsigns were missed?
Wheel issue caused 2014 Brockville CN Railtrain derailment, report finds
TSB blamed a combination of factors: the speed of the train,the type of car where the wheel issue manifested itself a 24-
metre-long "centrebeam bulkhead flat car" and the worncondition of the side bearings.
47
GM recalling 125,783 cars in Canada; oilleaks can cause engine fires
For the third time in seven years, General Motors is recallingcars that can leak oil and catch fire, in some instances
damaging garages and homes.
The recall, which covers 1.4 million vehicles, including125,783 in Canada, dating to the 1997 model year.
It is needed because repairs from the first two recalls didn’twork. More than 1,300 cars caught fire after they were fixed
by dealers, the company said.
Over time, a valve cover gasket can degrade, allowing oil toseep out. Under hard braking, oil drops can fall onto theexhaust manifold and catch fire. Flames can spread to a
plastic spark plug wire channel and the rest of the engine.
Ref; http://globalnews.ca/news/2301255
Ref: IAEA-TECDOC-1551 Implementation Strategies and Toolsfor Condition Based Maintenance at Nuclear Power Stations
Proactive – How Do You Compare?
48
PAS55(Publically Available Specification)
ISO55000
Production
Pumps, motors, fans, compressors, mills, lathes,
or whatever generally have moving and
stationary parts. Between them you need
something to reduce friction and wear. Often
this is a lubricant.
How good it is affects efficiency.
How well it and the bearings are maintainedaffects productivity.
Knowing how these are doing is conditionmonitoring.
49
Condition Monitoring - Why
To make the most effective use of materiels by
assessing equipment condition. One goal is get
an early indication of any adverse condition
before it can cause significant consequential
damage, affect production and/or product
quality.
Some techniques can identify problems before
there is damage.
Condition Monitoring - Why
Misalignment, unbalance, loose support bolts,
failing impellors, worn bearings, failing
bearings, lubrication issues, electrical problems,
plugging filters, wrong oil levels, leaks, etc.
Proactive measures can sometimes prevent the
problems in the first place.
50
Condition Monitoring - What Else?
Failure mode, effects and criticality analysis
(FMECA) is an extension of failure mode and
effects analysis (FMEA) by including a criticality
analysis. It is used to chart the probability of
failure modes against the severity of their
consequences.
54
‘Green’ Lubes
EU Ecolabel
Environmental Choice (Canada)
Green Seal (U. S. A.)
Eco Mark (Japan)
Ecolabel (United Kingdom And Italy)
NF Environment (France)
Blue Angel (Germany)
55
What Makes it ‘Green’
Readily biodegradable
Less aquatic toxicity
Does not bioaccumulate
Does not contain mineral oil
Does not contain more than ‘X’ additives
Sustainable
Recyclable
Reusable
Lasts longer
No heavy metals, VOC, or halogens
Recyclable container
Less wear, fuel efficient or better in someregard
Overview
There is not one answer for what to use,
what to monitor or when, where and how.
It depends on the application including the
equipment involved, the process, the cost of
failures, as well as the capabilities of the
personnel plus safety and environmental
considerations.
56
Overview cont’d
Fortunately many tools are available for
monitoring.
The key is know what is ‘normal’ and taking the
appropriate actions. Quantifying key
characteristics, trending and bench marking can
be very helpful.
A great deal of good information is readily
available.
Summary
1. Except for gross overloading, mostequipment problems will give someindication of distress ‘long’ before there issignificant consequential damage.
2. An effective condition monitoring programgenerally requires the integration of anumber of techniques and staff.
3. Trend plotting can be extremely helpful toshow degradation and the effectiveness ofproduction and maintenance actions..
57
Summary cont’d
4. There has to be realistic measures in place tofoster effective condition based maintenanceand continuous improvement.
5. There has to be enough training to know what isright, what is wrong, who to contact and whatto do.
6. There has to be open lines of communications.
Thank youThank you
www.stle.orgwww.stle.orgwww.stletoronto.comwww.stletoronto.com