ANTI-OXIDANTS AND CONTAMINATION CONTROL

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ANTI-OXIDANTS AND CONTAMINATION CONTROL

• YOUR EQUIPMENTS HEALTH DEPENDS ON THEM

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LUBRICANTS
To appreciate the need for the monitoring of
anti-oxidants and contamination a brief look at
the composition of a typical modern lubricant is
beneficial. The next slide depicts the components
of a lubricant and describes their function in
the lubrication process. Each component of the
lubricant wheel is hyperlinked to the appropriate
description of the additive or base oil allowing
you to progress as fast or a slow as you want
through the information provided. Use the
button to proceed. Once a better
understanding of the lubricant is realised, the
need to monitor these properties becomes more
evident for the continued protection of the
lubricant as well as the compartment.
CONTINUE
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BASE OIL
POUR POINT DEPRESSANT
ANTI-OXIDANT
BLENDED TOGETHER TO PRODUCE LUBRICANTS TO
SPECIFICATION
CORROSION INHIBITOR
ANTI-FOAM ADDITIVE
DETERGENT DISPERSANT ADDITIVES
VISCOSITY INDEX IMPROVER
ANTI-WEAR and EP ADDITIVES
CONTINUE
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MINERAL BASE OILS
Base oils transport additives to areas where
protection is needed. The lubricating oil
fractions from the refinery after purifying and
de-waxing are referred to as mineral base oils.
They are made up of Normal paraffinic (or
saturated) molecules, most stable to
oxidation Branched chain paraffinic molecules
(naphthenics), less stable to oxidation Aromatic
(or unsaturated) molecules, prone to
oxidation Base oils are classified by Group
Numbers GROUP I Normal Paraffin content 50
typical Naphthenic content 45
typical Aromatic content 5 typical GROUP
II Normal Paraffin content 65
typical Naphthenic content 34
typical Aromatic content 1 typical GROUP
III Normal Paraffin content 85
typical Naphthenic content 15
typical Aromatic content 0 typical
MAIN DIAGRAM
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SYNTHETIC BASE OILS
Although GROUP III oil based products can be
marketed as synthetic or semi-synthetic products,
they are not truly synthesised in the true sense
of the word. The two main types of synthetic oils
are POLYALPHAOLEFIN (PAO) and ESTER based
synthetic oil are chemically manufactured from
appropriate raw materials. GROUP IV PAO base
oils are manufactured using unsaturated
hydrocarbon molecules called olefins. The
simplest olefin is ethylene gas which can be
manufactured synthetically or obtained as a
product from the crude oil refining process
and is usually the olefin of choice for
manufacture of PAO base oils. By combining
individual molecules of ethylene (known as an
alpha olefin) in a process called
polymerisation saturated long chain
paraffinic hydrocarbons are produced. Oil
produced in this way is very oxidation stable.
Being a synthetically produced hydrocarbon,
these base oils are compatible with mineral
base oils. GROUP V These oils are synthetically
manufactured by reacting organic chemicals
together to form a very stable ester in the form
of an oil. They are typically characterised by
being very light (ISO 22-ISO 32) grade, very
stable to oxidation and fluid at very low
temperatures. Polyol ester base oils have
higher viscosities.
MAIN DIAGRAM
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• Treatment of metal surfaces to prevent corrosion
  due to entrapped air is catered for by the
  inclusion of a CORROSION INHIBITOR similar to
  that supplied in cooling systems. The inhibitor
  acts in two main ways
• wetting the exposed surfaces with a layer of
  additive
• react preferentially with air and water thus
  preventing its attack on metals surfaces.
• Typically the corrosion inhibitors are of the
  amine and phosphate type compounds which absorb
  oxygen and prevent rusting. They also react with
  acidic by-products of wear to prevent attack on
  vulnerable metal surfaces.

MAIN DIAGRAM
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Frictional forces within a lubricated system tend
to generate wear by metal to metal contact. The
heat generated by this contact is so severe that
the metals weld together and further motion of
the surfaces tears these welded sections apart
creating a rough surface and wear debris. An
additive called ANTI-WEAR Additive utilises the
heat generated to chemically bond with the metal
surfaces and prevent future welding and in doing
so retards the wear effect. A typical engine
anti-wear additive is Zinc Dialkyl
DithioPhosphate (ZDDP) sometimes referred to
merely as zinc anti-wear additives. ZDDP also
acts as an Anti-oxidant.
Extreme pressure (EP) additives are typically
composed of Phosphorus/Sulphur compounds which
bond to the moving surfaces under heat of welding
and shearing of the metal to metal contact. This
bonding imparts a slippery surface on the
moving components exposed to wear and provides a
better surface to counteract wear.
MAIN DIAGRAM
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Multigrade oils have been introduced into the
modern lubricated equipment to give them the
capability to lubricate at cold starting to
minimise start-up wear while being able to
provide the specified lubrication at operating
temperature. Base oils by themselves have a
characteristic thinning out when the
temperature increases from cold start to
operating temperature. The relationship between
increasing temperature and corresponding
decrease in viscosity (thickness) of the oil is
known as the Viscosity Index (VI). To increase
the natural VI of the oil and thus increase the
lubrication ability of the oil at elevated
temperatures, an additive called a VISCOSITY
INDEX IMPROVER is added to the blended oil. VI
Improvers are typically long chain hydrocarbon
compounds. The VI improver retards the thinning
out of the oil when heated but does not interfere
with the lubricant when cold.
MAIN DIAGRAM
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Air is a lousy lubricant. Air entrapment in
lubricated components permits metal to metal
contact and results in excessive wear. An
additive must be included to permit the air to
quickly dissipate from the oil. This is called
ANTI-FOAM additive and is generally in the form
of a silicone type oil in the order of up to 10
parts per million.
MAIN DIAGRAM
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• ANTI-OXIDANTS are chemicals added to a lubricant
  to protect the base oil of the lubricant and
  thereby protecting the equipment being
  lubricated.
• The anti-oxidant additives are designed to be
  sacrificially consumed during the life of the
  lubricant and are the first of the additives in
  an oil to deplete.
• If the Anti-oxidant level depletes to below 30
  of the original concentration, it can no longer
  completely protect the lubricant nor the
  equipment.
• Anti-oxidants operate in several ways.
• reacting with entrapped air to prevent varnish
  formation in the base oil.
• preventing formation of degradation by-products
  in the oil in high friction areas.
• neutralise the effects of metallic wear
  particles that could lead to degradation of the
  oil.
• neutralise the effects of moisture that could
  lead to degradation of the oil.
• Conventional Anti-oxidant additives are amines
  and phenols. In some cases anti-wear additives
  such as Zinc Di Alkyl Di ThioPhosphate (ZDDP)
  have an anti-oxidant effect and can also be
  monitored.

MAIN DIAGRAM
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Detergents in oil clean surfaces within the
lubricated compartments (usually engines).
These additives also keep the material removed
in suspension until it can be removed by the
system filters or by change-out. These additives
chemically protect oil from attack and neutralise
acids that are formed by fuel combustion.
Dispersants are chemicals which when added to
oils assist the detergent additive keep the
contamination which it has cleaned from surfaces
as well as other introduced contaminants such as
water (and soot in engines) in suspension until
the contamination can be removed.
MAIN DIAGRAM
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In cold climates, the oil may freeze and starve
the lubricated components of oil causing wear. An
additive that inhibits the freezing
characteristics of the oil (in much the same way
as glycol in the cooling system inhibits freezing
of the water) is blended into the oil. This
additive is the POUR POINT DEPRESSANT The name
POUR POINT relates to the temperature at which
the lubricant can just flow., ie a couple of
degrees cooler, the oil will, in fact, NOT FLOW.
MAIN DIAGRAM
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Lubrication of a Compartment requires an Oil with
Additives to

• Prevent wear

• Clean Disperse

(For engines)

• Counter Oxidation

• inhibit corrosion

• Keep the Oil Fluid

• Reduce Foaming

AND filtration to
KEEP THE OIL CLEAN
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MAXIMISING THE OIL LIFE IN EQUIPMENT
Although the lubricant is still considered the
cheapest replaceable item in large plant and
equipment, the oil has a finite cost, both to
purchase as well as dispose of, and to obtain
full value, the oil should be changed out only
when it can no longer effectively protect the oil
and the moving surfaces. The additive in the oil
formulation that provides this protection is the
ANTI-OXIDANT which can be measured using RULER.
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RULER Oil Condition Monitoring

• R emaining
• U seful
• L ife
• E valuation
• R outine

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RULER Oil Condition Monitoring

• Definition
• Remaining Useful Life of lubricants
• Length of equipment operating
• time from the time a lubricant is
• sampled based on anti-oxidant level readings
  of a standard for the lubricant

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RULER Oil Condition Monitoring

• Remaining Useful Life dependent on

OPERATING CYCLE
ANTI-OXIDANT TYPE
BASE OIL OXIDATION STABILITY
PRESENCE OF METALS /OR WATER
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RULER Oil Condition Monitoring

• RULER Oil Degradation
• R.U.L.
• 100
• 
  
• 50
• 0
  
  Operating Time (hours months km )

Viscosity
Critical Point
TAN
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Critical Point
In the service life of a lubricant the
anti-oxidant (AO) additive incorporated into the
formula preferentially depletes until a stage is
reached where there is insufficient AO left to
FULLY protect the base oil(s) and the equipment.
This point is referred to as the CRITICAL POINT
and is typically set at 30 RUL. Continued use of
the lubricant after the critical point has been
reached will result in escalating values for
Total Acid Number (TAN) and viscosity due to oil
oxidation. Oil oxidation is evidenced by
formation of lacquers/varnishes and gums which
renders the oil unsuitable for redosing with
additives. Redosing with AO or changing out of
the lubricant prior to achieving the critical
point will enhance the longevity of oil, if
redosing, and the equipment making RULER a true
maintenance PRO-ACTIVE CONDITION MONITORING TOOL
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RULER Oil Condition Monitoring

• What are RULER APPLICATIONS ?
• Petrol engine oil
• Diesel engine oil
• Aircraft engine oils
• Steam turbine oils
• Gas turbine oils
• Hydraulic oils
• Compressor lubricants
• Transmission fluids
• Greases

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RULER Oil Condition Monitoring

• What is RULER METHOD ?
• LUB OIL/FLUID SOLVENT
• EXTRACTION OF ADDITIVES
• OIL PHASE ADDITIVES
• Substrate oil in solution
• settles down to electrolytic cell
• bottom of vial

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RULER Oil Condition Monitoring

• What is Cyclic Voltammetry ?
• Electrochemical analysis
• determining antioxidants concentration
• determining antioxidants depletion during
  lubricant use
• indicating the END of the Useful Life
• Remaining Useful Life Evaluation Routine

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RULER Oil Condition Monitoring
auxiliary working electrode electrode Cycl
ic Voltage reference 0 - 1,5 V
electrode 11 / 17 sec. RULER
Probe Solvent Additives mixture RULER
Sand Oil Insolubles
CE320 INSTRUMENT
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RULER Oil Condition Monitoring

QUALITATIVE
C U R R E N T
QUANTITATIVE PEAK HEIGHT

QUANTITATIVE PEAK AREA
ADDITIVE B
ADDITIVE A
V O L T A G E
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RULER Oil Condition Monitoring

• S
• T
• A
• N
• D
• A
• R
• D

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RULER Oil Condition Monitoring

• T
• E
• S
• T

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RULER Oil Condition Monitoring

• RULER TRENDING
• Successive samples measurement
• antioxidant additive depletion rate
• PROACTIVE FLUID MACHINE CONDITION MONITORING

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RULER Oil Condition Monitoring

• T
• E
• S
• T
• S

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RULER Oil Condition Monitoring

• T
• R
• E
• N
• D
• I
• N
• G

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RULER Oil Condition Monitoring
CE320 RULER IS A VALUABLE TOOL FOR

• Used oil condition monitoring

• Incoming lubricant batch control

• Additive replenishment/top-up detection

• Detecting abnormally operating equipment

• Detecting abnormally operating equipment

• Predicting extending oil change intervals

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• RULER augments standard analysis methods
• Diagnostic oil analysis programs are a
  jigsaw puzzle of many pieces in which all
  pieces are required to give a full picture of oil
  and equipment condition. RULER supplies the vital
  piece which can can tell how long the lubricant
  can last and how much protection it can supply
  to the lubricated component.

• RULER technology has been investigated and is
  now included in ASTM list of methods as ASTM
  D6810-02 and ASTM D6971-04

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RULER Oil Condition Monitoring

• RUL ()
• Operating Time

FRESH Oil replenishment
CHANGE in operating conditions
NORMAL Trending
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RULER Oil Condition Monitoring

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ANTI-OXIDANT DEPLETION can
be a reflection of normal wear rate would
generally be linear with the slope of the rate
line indicating the severity of the wear.
SOME WEAR
R U L
MORE WEAR
SEVEREWEAR
TIME
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ANTI-OXIDANT DEPLETION can
be a reflection of changing wear rate would
increase indicating change in wear. Change may be
due to INGRESS OF EXTERNAL SOLID CONTAMINATION
e.g dirt INGRESS OF EXTERNAL LIQUID CONTAMINATION
e.g. moisture CHANGE IN LOAD CHANGE IN
OPERATOR USE OF A LIGHTER VISCOSITY OR DIFFERENT
OIL FOR TOP-UP OR CHANGE PRODUCTION OF WEAR
PRODUCING PARTICLES IN SYSTEM
RATE CHANGE POINT
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FILTRATION
One of the major factors affecting the useable
life of a lubricant is its cleanliness.
Accordingly it is appropriate to provide a few
details of filtration and the various classes of
cleanliness commonly encountered
Filtration is the physical or mechanical process
of retention or capture of particles in a fluid
by the passage of the fluid through a porous
filter medium.
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ROLLER
3-5 MICRON
.
OIL FILM
FRICTIONAL AREA
INNER RACE
The lubricant is separating loaded surfaces by
means of a fluid film of between 3 and 5 micron
in thickness. The next slide gives a comparison
of micron sizes
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MONITORING SOLIDS FOR THEIR EFFECT ON LUBRICANTS
Solids of any size are detrimental to the
operational efficiency of lubricated components
leading to wear of moving surfaces and
degradation of the lubricant by depletion of
anti-oxidants and then oxidation of the base oil.
Having looked at the monitoring of the
properties of the lubricant and assessing the
lubricants condition, particularly the RULER
determinations of active anti-oxidant content, it
is just as wise to inspect the cleanliness of the
lubricant to determine the effectiveness of the
filtration in the system. The PODS instrument
depicted in the following slide is typical of the
affordable particle counting technology for
industry that makes testing on-site a reality in
the same way as RULER.
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PODS - PORTABLE OIL DIAGNOSTIC SYSTEM
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CLASSIFICATION OF FILTRATION

• MACRO FILTRATION - gt2 MICRON IN SIZE
• MICRO FILTRATION - 2 MICRON TO 0.2
  MICRON IN SIZE
• ULTRA FILTRATION - lt 0.2 MICRON IN SIZE

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FILTRATION PROCESS

• Gravitational separation from fluid- achieved
  by rotational forces applied to the fluid eg
  Glacier or Spinner
• Depth retention - direct interception and / or
  adsorption
• Surface retention - direct interception and /
  or adsorption

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BASIC FILTRATION MECHANISMS
FIBROUS

• cellulose
• cotton
• micro fibre glass
• synthetics

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POROUS MEDIA TYPE FILTERS

• SINTERED METAL
• CAST CERAMIC
• CAST PLASTIC
• FOAMED POLYMERS

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SURFACE FILTRATION MEDIA

• SCREEN
• ETCHED SHEET
• CAST MEMBRANE
• EDGE
• STACKED DISC

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EDGE FILTER TYPE PRINCIPLES
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FILTER RATINGS
ABSOLUTE RATING Diameter of largest hard
spherical particle permitted to pass NOMINAL
RATING Based on of largest particles permitted
to pass BETA RATING Ratio of upstream particles
of nominated size with downstream particles
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BETA RATING Ratio of upstream particles of
nominated size with downstream particles
BETA RATIO
EFFICIENCY 1
0 2
50
20
95 50
98 100
99
200 99.5
1000
99.9
Usual specification
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FILTRATION All filters will reduce the solid
matter contamination to the appropriate micron
size without detriment to the properties of the
lubricant, that is, they cannot remove the
additives from the oil formulations. Even
polymers employed as viscosity index improvers
and tackifiers will pass through the filters as
they are dissolved in the oil base. A good rule
of thumb to use when considering filtration of
oil is "If It Can Be Removed By Filtration It
Shouldn't Be There".
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SAE AS 4059(c) Aerospace standard recording
particles counted per 100 ml for all
size ranges from 4 micron to to greater
than70 micron ISO 4406 (c) International
Standard recording particles counted per
ml for size ranges from gt4 micron to
to gt14 micron Condition Monitoring Programmes
should include Particle Size Distribution
analysis for Hydraulic and Transmission and Drive
systems that incorporate forced lubrication and
filtration to gauge the effectiveness of the
filtration.
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INTERNATIONAL STANDARD 4406(c)
MEASUREMENT RANGE gt4um / gt6um / gt14um MORE THAN
LESS THAN ISO CODE 5 000 000
particles/ml 10 000 000 particles/ml 30 2 500
000 5 000 000 29 1 300 000 2 500
000 28 640 000 1 300 000 27 320 000
640 000 26 160 000
320 000
25 80 000 160 000 24 40
000 80 000
23 20 000 40 000
22 10 000 20 000 21
5 000 10 000 20 2 500
5 000 19 1 300 2 500
18 640 1 300 17
320 640 16 160
320 15 80
160 14 40 80 13
20 40 12
10 20 11
etc..
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ISO REPORTING
gt 4 MICRON / gt6 MICRON/ gt14 MICRON INCLUDES
INCLUDES INCLUDES SILT
FINE WEAR COARSE WEAR /OR DIRT
/OR DIRT /OR DIRT
FINE WEAR COARSE
WEAR /OR DIRT /OR DIRT COARSE
WEAR /OR DIRT
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SUMMARY
MONITORING THE ACTIVE ANTI-OXIDANT LEVEL AND
PARTICULATE CONTAMINATION LEVEL LETS YOU KNOW HOW
GOOD THE LUBRICANT STILL IS AS OPPOSED TO
MONITORING WEAR AND OTHER ABNORMAL VALUES WHICH
LETS YOU KNOW HOW BAD IT HAS BECOME.