2012 condition monitoring workshop assct conference -alan yarrow-2

ISS Machine Health Group machinehealth.com

Sugar Mill Condition Sugar Mill Condition MonitoringMonitoringMonitoringMonitoring

ASSCT 2012 ConferenceASSCT 2012 ConferencePresentedPresentedPresentedPresented

bybyAlan S YarrowAlan S Yarrow

1

Condition monitoring became a serious fundedCondition monitoring became a serious funded research/development project after several UK Navy

helicopter accidents in 1971 1983 two civilian Chinooks had fatal gearbox failures. 18 soles were lost in the Northsoles were lost in the North Sea oil fields.This is part of a presentation to the UK CAA in1984to the UK CAA in1984 presenting the VA capabilities of the UK Navy science at the time.science at the time.

Four years and ₤3m later, every UK Chinook measured the stiffness of h t th i th t i t ti ll 300 d ! Ieach gear tooth in the power train automatically every 300 seconds! In

the next five years two incipient catastrophic failures were detected and avoided.

2

Machinery


Operator Input Operating RecordsCondition

“However Maintenance

Monitoring

However, Murphys will still

happen!”

ManagementProgramme

S tiUnscheduledRepair or

SometimesUnnecessaryperiodic

Planned On-Condition Repair or

Breakdownperiodic maintenanceMaintenance

3

Assessing the rewards from condition monitoring.


Assessing the rewards from condition monitoring.Sa

ving Good Visible

Rewards From In estment

e C

ost S

Investment

enan

ce Hard to JustifyInvestment

UnpreventableLosses

Mai

nte Losses

Investment in Condition Monitoring4

S gar Mill Condition Monitoring


Sugar Mill Condition Monitoring Brings Special Problems

• For an external provider, the seasonal nature of sugar milling causes manpower issues.

(In comparison with a continuous process eg. a coal wash plant).

g p• With continuous crushing irregular maintenance days,

make it impossible to follow a fixed CM survey scheduleschedule.

• Weather disruptions also make for a lot of “short notice” are you crushing calls.

h i l b i i f h f• The seemingly obvious answer is for each group of mills to have its own “in-house” condition monitoring group – now called reliability engineering.

• We are very supportive of the idea of “in house” condition monitoring. 5

I h C diti M it i


In house Condition Monitoring. Some advantages.

• Response time.• Complete controlComplete control.• Good local knowledge.• Excellent feedback loop• Excellent feedback loop.• Better targetting of monitoring.

C t t l• Cost control.• etc

6

I h di i i i


In house condition monitoring.Dis-advantages.

• Normally - limited knowledge/training..• Sometimes dated equipment.• Staff promotion rotation.• Career path problems.

Of CM b d k b• Often CM becomes a secondary task to be done when the Engineer has “spare time”.

• Etc• Etc.• The ideal is possibly an “in-house” CM

program with formal specialist support.p g p pp

7


Condition monitoring techniques

• Vibration Analysis• Oil Analysis*Oil Analysis • Used Grease Analysis*• Magnetic Chip Collector and• Magnetic Chip Collector and

Filter Debris Analysis• Thermography• Thermography* Ferrography is used as an

adjunct to these techniquesadjunct to these techniques.8

Oth I t t M it i


Other Important Monitoring Techniquesq

• Temperature trending• Performance monitoring• Performance monitoring• Additive depletion• Mk I Eyeball• Mk I Eyeball• Smell

F l• Feel

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Often Condition Monitoring T h i C lTechniques are Complementary.

i il d d di iVibration anal sis nlikel to detect the fretting fail re• Different failure modes produce differing CM indications.

Vibration analysis unlikely to detect the fretting failure of a coupling.

• Different CM techniques are sensitive to differing failure modes.

Equally do not use oil analysis to monitor a gear drive for cracked gearing.

Each is a valid monitoring technique in its own right, but will fail when presented with the above problems.

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Vibration Vibration Analysis Analysis T h iT h iTechniques Techniques

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Ideal Vibration Sampling Cycle - TheoryISS Machine Health Group

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14 Day Analysis Cycle

28 Day Analysis Cycley y y

2 X Preferably 3 X per season

Critical(Immediate effect on production)(Immediate effect on production)

Importantp(Effect on production within a shift)

RoutineRoutineEffect on production within days or for

maintenance planning12

Vibration Sampling Cycle - Interruptions


Vibration Sampling Cycle Interruptions

Problem Machines

InvestigationsInvestigations

Quality Assurance

13


Time

Vibration signatures are generally aVibration signatures are generally a composite from multiple sources. 14


Defect Versus “Normal” Machine Vibration Frequency DistributionVibration Frequency Distribution.

Movements

agni

tude Stress waves

F

Ma

Frequency

15

Vibration Detection of Gearing Faults

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Dispersed Gearing FaultsISS Machine Health Group

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Dispersed Gearing FaultsPoor Meshing

High tooth mesh energyenergy

Side banding

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Dispersed gearing faults poor meshing


Dispersed gearing faults poor meshing

Multiple gear meshMultiple gear mesh harmonics

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Localised gear faults are difficult to


Localised gear faults are difficult to detect compared to dispersed faults.

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Localised gearing faults do not indicate


Localised gearing faults do not indicate well in the frequency domain

Tooth mesh energy bi d fcombined energy from

112 meshes. If one tooth fault generates 10X the gnormal mesh energy.

The overall mesh energy in the frequency domainin the frequency domain will only increase by 9%.

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To analyse gear di i i VAcondition using VA

requires complete k l d f hknowledge of the configuration.

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Typical gearing details ISS Machine Health Group

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yp g grequired for analysis.

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i l iGearing AnalysisTime Synchronous AveragingTime Synchronous Averaging

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Gearing Analysis - TSAISS Machine Health Group

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Gearing Analysis - TSA

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Time synchronous averaged waveform

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Time synchronous averaged waveform.ISS Machine Health Group

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y g“The invisible missing tooth”.

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Epicyclic gearboxes pose special problemsspecial problems.

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Vibration analysis and rolling element


Vibration analysis and rolling element bearing failures.

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Bearing defect vibrations.ISS Machine Health Group

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Bearing defect vibrations.

High FrequencyHigh FrequencyImpulsive (stressWave) vibration.

UnfilteredFFT Spectra Audible Noise

or Rumble

Onset of

Failure

Onset of Defect

Operating Time

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Vibration analysisHigh frequency resonance techniques

Fmax CutoffHigh Pass Filter

Fmax Cutoff

ude

Band PassFiltered

Mag

nitu

Frequency

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High Frequency Resonance DetectionHigh Frequency Resonance Detection (HFRD)Band Pass Filter

R tifRectify

Envelope

Demodulate

Am

plitu

de

O Hz

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High frequency demodulation (stress


High frequency demodulation (stress wave) detection.

2.5mm

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Inner race fault indication


Inner race fault indication

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“Infant mortality”


Infant mortalityAn example where `new’ is not as good as `used’.

Overhaul.

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Corrosion initiated fault

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Not all bearing failures present constant fault


Not all bearing failures present constant fault vibration, some play “hide and seek”.

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Mechanical LoosenessISS Machine Health Group

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Mechanical Looseness.

37

Vib ti lit d & h f


Vibration amplitude & phase for machinery shape deflectionsy p

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Oil AnalysisOil Analysis ISS Machine Health Group machinehealth.com

• Wear Debris Monitoring.b i li i i• Lubricant Quality Monitoring.

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The ISS procedure for a routineISS Machine Health Group

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The ISS procedure for a routine Oil Sample: -

Oil OSample

PQ Index

Other Monitoring Technique Results. Eg. Vibration Analysis

Oil Test* –Routing Analysis

Partner

Ferrographic study of wear

particle morphologymorphology

ISO 13374-1 Combined condition monitoring report

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Moisture in OilISS Machine Health Group

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Moisture in Oil

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Water DamagedDamaged bearing surface

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Particle Wear Mode Size Vs Technique Size Sensitivity


Particle Wear Mode Size Vs Technique Size Sensitivity

Inductive Techniques

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Ferrography and wear particle ISS Machine Health Group

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g p y pdiagnostics of oil and grease samples

44

W P i l Di i


Wear Particle DiagnosticsFerrogramg

45

W P i l Di i


Wear Particle DiagnosticsFerrogramg

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Wear Particle DiagnosticsISS Machine Health Group

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Wear Particle DiagnosticsRolling Contact Fatigue

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Wear Particle DiagnosticsISS Machine Health Group

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Cam or roller - rolling contact fatigue.

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Wear Particle Diagnostics

S h i l ti l l d f b ll ?Spherical wear particles or a load of balls?49

Laser Particle CountingISS Machine Health Group

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Laser Particle CountingMulgrave Laser Particle Counts - 2 micron Particles

20000

14000

16000

18000

10000

12000

artic

le C

ount

No 1 PF TopNo 1 PF BottomNo 1 Top Roll PSNo 1 Top Roll GSNo 1 Feed RollNo 1 Delivery Roll

4000

6000

8000Pa

No 1 Delivery RollNo 3 Press FeederNo 5 Press Feeder

0

2000

29-Jun-99 19-Jul-99 08-Aug-99

28-Aug-99

17-Sep-99

07-Oct-99 27-Oct-99 16-Nov-99 06-Dec-99

26-Dec-99

15-Jan-0099 99 99 99 99

Sample Date

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Laser Particle CountingLaser Particle CountingMulgrave Laser Particle Counts - 5 micron Particles

3000

2000

2500

No 1 PF Top

No 1 PF Bottom

1500

Part

icle

Cou

nt p

er m

l No 1 PF Bottom

No 1 Top Roll PS

No 1 Top Roll GS

No 1 Feed Roll

No 1 Delivery Roll

No 3 Press Feeder

500

1000

P No 5 Press Feeder

ISO 16

020-May-99 09-Jul-99 28-Aug-99 17-Oct-99 06-Dec-99 25-Jan-00

Sample Date

51

Laser Particle CountingISS Machine Health Group

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Laser Particle CountingMulgrave Laser Particle Count - 15 micron Particles

800

1000

No 1 PF Top

No 1 PF Bottom

600

Part

icle

Cou

nt p

er m

l No 1 PF Bottom

No 1 Top Roll PS

No 1 Top Roll GS

No 1 Feed Roll

No 1 Delivery Roll

No 3 Press Feeder

200

400P No 5 Press Feeder

ISO 13

020-May-99 09-Jul-99 28-Aug-99 17-Oct-99 06-Dec-99 25-Jan-00

Sample Date

52

Self Sealing Magnetic ChipISS Machine Health Group

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Self Sealing Magnetic Chip Collectors

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Magnetic Chip Collectors• Very cost effective monitoring technique.• Ideal for mobile plant• Ideal for mobile plant.• Self sealing MCC provides and excellent oil

li i tsampling point.• Provides a certain amount of go/no go

information on site.• Once experience builds prognosis can be p p g

very accurate.54

Critical MCC ti lparticles can

often be seen ith th id dwith the unaided

eye.

B ll B iBall BearingFatigue 55


Hagglunds DrivesB2 Mill MCC Wear TrendsMagnetic Chip Collector Trending

800

Deb

ris)

400

600

ex (F

erro

us W

ear

200

umul

ativ

e PQ

Inde

037092 37112 37132 37152 37172 37192

Acc

u

Sample Date

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On Line Wear Debris MonitoringISS Machine Health Group

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Debris and water indicatingFilter Unit (8 debris zones)Filter Unit (8 debris zones).Built for Shredder bearingmonitoring.

57


Thermography

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Thermography

59


Thermography

60


Vibration analysis tools can provides peripheral benefits beyond just condition monitoringbenefits beyond just condition monitoring

including:

•In field balancing.Q li•Quality assurance.

•Dynamic investigations

61


Hand (static) balancing will nearly always fail with sugar mill fans y g

Static Unbalance

f i h A h

Dynamic Unbalance

If weight A = B thenIf weight A = B then machine balanced

when stationary and running.

If weight A = B then machine only

balanced when not running.

62


Q li A O h l d l bQuality Assurance – Overhauled cane elevator gearbox

18/06/2009

11/11/2008

150µm Bevel gear mesh energy Rubbing/scuffing wear only

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Q li A O h l d C El G bQuality Assurance – Overhauled Cane Elevator Gearbox

Time synchronous averaged time waveform showing “poor” meshing profile for the 20 tooth bevel input gear.

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Fugal instability problems. l l i i iBalance tolerance investigations


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However, condition ISS Machine Health Group

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monitoring is not a panceaand never will be!and never will be!

And at $20,000 plus per h d ti thi t d thour downtime this tends to

bring out the pinapples!bring out the pinapples!

66


Clear indication of a developing bearings fault.Clear indication of a developing bearings fault. Y scale 0 - .00025g 67


Hydraulic pump vibration. Y-axis scale 0 – 0.15g

68


Q ti di iQuestions or discussion points?p

Bearing fault vibration on the same l hscale as the pump.

Y-axis scale 0 – 0.15g 69


Acknowledgements

My thanks must go to all the sugar mill engineers who have taught me the subtle differences between sugar mill and helicopter machinery over the years. This applies especially to those Engineers from the Sugar North group of mills.

70


Q ti di iQuestions or discussion points?p

71

2012 condition monitoring workshop assct conference -alan yarrow-2

Documents

condition sugar

condition repair

iiss machine health

condition monitoring4s

group of mills

th t i t ti ll

stiffness of h t th

grease analysis