What are the Benefits?
- Improved maintenance planning
- Increased equipment reliability
- Increased fluid life ( in some instances)
- Fewer unscheduled shutdowns
- Reduce catastrophic failures
- Overall improvement in product quality
- Improved inventory control
- Energy savings
What do we Monitor?
- Temperature
- Pressure
- Flow
- Horsepower
- Voltage, current
- Torque
- Vibration
- Fluid condition
PRINCIPLE OF LUBRICATION
Support a sliding load on a
friction reducing film.
(Reduce metal to metal contact.)
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Key Functions of Lubricants
- Reduce friction/wear
- Protect against corrosion and wear
- Assist sealing
- Cooling
- Overcome effects of contaminants
The Different Lubricating Conditions
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HYDRODYNAMIC LUBRICATION
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Ideal situation
- Conditions
- Correct viscosity
- High speed
- Low load
- Adequate supply of lubricant
HYDRODYNAMIC LUBRICATION
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- Poor Lubrication
- Metal-to-metal contact
- Wear
- Extreme case can cause welding of the metal surfaces
- Conditions
- Low viscosity lubricant
- Low speed
- High load
- Lack of lubricant
BASESTOCK - LUBRICANT PERFORMANCE
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BASE OIL PROPERTIES
- What determines a base oil's chemical composition?
- Crude source
- hydrocarbon types
- sulphur & nitrogen content
- viscosity index
- light or heavy fractions
- colour & odour
BASE OIL PROPERTIES
- What determines the base oil's chemical composition
- Refining technique
- physical separation
- chemical alteration
VISCOSITY INDEX
- VI is a measure of the rate of change of viscosity Vs. temperature
- The higher the VI, the lower the viscosity change of the oil with temperature
Viscosity / Temperature Comparison
Single Grade VS. Multigrade Oils
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NEW PUMP SPECIFICATIONS
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NEW PUMP TESTS
- Both Vickers & Denison have new tests
- Vickers 25VPF & DenisonT6C are more severe, high performance tests
- Base stock quality critical in hydraulic fluids, 95% - 98% of formulation.
- New XHVI stocks offer better oxidation resistance, air release & filtration properties
FLUID DEGREDATION
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The process of fluid degradation is irreversible
HIGH TEMPERATURE
- Temperatures in paper machine dryer sections, steel mill rolls etc, combined with water can cause the base oils to break down.
- High molecular weight products form gums & varnishes & acids, oil reacts with oxygen
- Yellow metals can act as catalyst and aggravate acid formation.
Increases viscosity
WATER
- Lubricants are subject to large amounts of water in some applications
- Demulsibility important
- Greases also subject to water contamination
- Additive systems can be leached out
- Reduces viscosity
CONTAMINATION
- Wear metals
- Paper fibers
- Storage
- Airborne dirt
- All can degrade fluid life and or accelerate degradation.
- Good filtration essential.
LUBRICANT FILMS
- In hydrodynamic bearings "oil whip" can occur
- Self excited destructive vibrations set up
- Occurs at slightly less than 1/2 running speed
- Subharmonic resonance occurs exactly at 1/2 or other exact multiple of running speed
FLUID ANALYSIS
SPECTROMETRIC ANALYSIS
- Many commercial labs today use Inductively Coupled Plasma Spectrometer (ICP) or Direct Current Plasma Spectrometer (DCP)
- Useful for wear metals, lubricant additives, contamination
- Measures particles up to 10 microns
VISCOSITY
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The key property of any lubricant
PARTICLE COUNTS
- Can measure particles from < 2 to > 100 microns
- Will measure metallic & non-metallic particles
ISO 4406 now common
FERROGRAPHY
- Use tool to measure size and shape of particle
- Captures large variety of particle sizes
- Assists in determining failure mode
TRENDING
- Any analysis must be done over period of time
- Trends of contamination levels, types of wear debris, viscosity change will assist in determining optimum lubricant/machine life
SUMMARY
- There are definite benefits to be derived from have a good PdM program married with a fluid
- analysis program.
- Longer system life - equipment & fluid
- Fewer catastrophic failures
- Less unscheduled downtime
- More efficient use of manpower
- Lower inventory/disposal costs
THANK YOU
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