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CONDITION MONITORING THROUGH NON DESTRUCTIVE TESTINGS OF MACHINES AND
PLANTS
INTRODUCTION
• CONDITION MONITORING
• SIGNATURE ANALYSIS
• NON-DESTRUCTIVE EVALUATIONS(NDE)
• IN-SERVICE INSPECTIONS (ISI)
• SAFTEY
fig 1.c detection methods of failures
vibration45%
others4%
acoustic emission3% fluorescence
3%
torque6%
rotational speed6%
temperature10%
oil analysis23%
vibration
oil analysis
temperature
rotational speed
torque
fluorescence
acoustic emission
others
CONDITION BASED MAINTENANCE
2.PREVENTIVE2.PREVENTIVE
3.PREDICTIVE3.PREDICTIVE1.BREAK DOWN 1.BREAK DOWN
MAINTENANCEMAINTENANCE
NDE TECHNIQUES
1.VIBRATION MONITORING1.VIBRATION MONITORING
2.ACOUSTIC EMISSION (AE)2.ACOUSTIC EMISSION (AE)
3.INFRARED THERMOGRAPHY (IRT)3.INFRARED THERMOGRAPHY (IRT)
4.FERROGRAPHY4.FERROGRAPHY
5.FIELD SIGNATURE MAPPING (FSM)5.FIELD SIGNATURE MAPPING (FSM)
VIBRATION MONITORING INSTRUMENTATION
• VIBRATION MEASURING AND ANALYSIS SYSTEM
VIBROMETER CHANNEL SELECTOR
FREQUENCYANALYSER
RECORDER
fig,(1.a) SIGNAL FLOW DIAGRAM
MACHINE
• MINI COMPUTERS
• PROBABILITY DENSITY FUNCTION ANALYSIS (PDF)
• BY INSPECTION
ANALYSIS OF RESULTS1. VIBRATION CAUSE IDENTIFICATION
Sl No
FAULT FREQUENCYDIRECTION OF VIBRATION
1ROTATING UNBALANCE
SAME AS RUNNING SPEED RADIAL
2MISALIGNMENT OF BEARINGS
2*SPEEDRADIAL AND AXIAL
3ROLLER BEARING DEFECT
AT BALL OR ROLLER SPEEED ULTRA SONIC FREQUENCIES(20-60KHz)
RADIAL AND AXIAL
4.OIL FILM WHIRL IN HIGHSPEED TURBO MACHINES
0.5*SPEED RADIAL
5DAMAGED OR WORN GEARS
No: OF TEETH* RPM RADIAL
VIBRATION METER (HAND HELD)
Vibration Meter : for imbalance, structural weakness, loose parts etc
INDUSTRIAL MACINERY CLASSIFICATIONClass 2: Medium size machines without special foundation Class 3: Large machines on rigid foundations Class 4: Large machines on soft foundations.
SPM VIB-11 by SKF
fig 1.c detection methods of bearing failure
vibration45%
others4%
acoustic emission3% fluorescence
3%
torque6%
rotational speed6%
temperature10%
oil analysis23%
vibration
oil analysis
temperature
rotational speed
torque
fluorescence
acoustic emission
others
fig2. failure rate of different machineries of plant
others24%
rolling bearing29%
slide way13%
valve6% sliding bearing
6%
seal7%
gear7%
oil pump8%
valve
slidingbearingseal
gear
oil pump
slide way
rollingbearingothers
APPLICATIONOF VIBRATION MONITORING IN PLANTS
• MONITORING AT ‘ROURKELA STEEL PLANT’
• maintenance cost 10-15% of prod: cost
GROWTH THROUGH CBM ACTIVITIES AT RSPN
o:
of
ma
chin
es0
20
40
60
80
100
120
94-95 95-96 96-97 97-98 98-99 99-00
breakdownsprevented
savings
insitu balancing
trend line
year
BREAK DOWNS PREVENTED-10-102
EQUIPMENTS INCLUDED - 40-140
ACOUSTIC EMISSION MONITORING
AE sensors respond with amazing sensitivity to motion in the low ultrasonic frequency range (10 kHz - 2000 kHz). Motions as small as 10-12 inches and less can be detected
ACOUSTIC-EMISSION METHOD
This method is based on the registration of the elastic compression waves that are emitted by the defects developing in the stressed constructions.
ACOUSTIC EMISSION SYSTEMS
AE data collection systems
•Laptop based AE system •DiSP Systems (any number of channels can be used)• Portable AE test system (lunch box)
Pressurization (Stage 1)Random AE activity due to1. Mechanical rubbing between support
structure and vessel2. Paint layer peel-off .Re pressurization (Stage 2) No significant AE activity
CASE STUDY
AE DURING HYDROTESTING OF A HORTON SPHERE
MAX: PRESSURE 22 Kg/cm2
Fig.2(f) AE monitoring during hydro testing of Horton sphere
•AE SIGANLS FROM NEWER AREA ( local plastic deformation )
•NO SIGNAL DURING SUBSEQUENT PRESSURIZATION
IR THERMOGRAPHY
• Infrared thermography is based on the principle of detection and measurement of infrared radiations QR) arising from the natural or stimulated thermal radiation of an object21
TypeVARIOSCAN 3021 ST
Spectral range [µm]
8 ... 12
Detector material
Hg, Cd, Te
Detector cooling Stirling-cooler
I R MEASURING SYSTEMS
ThermaCAM S60 : Real-Time Thermal
•highly sensitive thermal imaging,•precision temperature measurement, •enhanced connectivity options including •high speed data transfer •extensive thermal analysis capabilities
raw thermo graphic data.
data after removing the noise and vertical gradient.
data processed for the local gradient in surface temperature.
CASE STUDY
high strength welds
Fig setup for infrared testing of lap joints
correspond to low strength welds.
FERROGRAPHY1.WEAR DEBRIS ANALYSIS
MODE: ABRASION, IMPACT, FATIGUE, EROSION, CORROSION RATE : CONCENTRATION OF WEAR DEBRIS SEVERITY : SIZE OF DEBRIS INDICATES LOCATION : COLOUR OF THE PARTICLES
2.SPECTROMETRIC ANALYSIS
•OIL ELECTRICALLY EXCITED TO THE POINT WHERE LIGHT IS EMITTED.
•ELEMENT EMITS A LIGHT OF ITS OWN PARTICULAR COLOR AND FREQUENCY.
•SPECTROMETERS TRANSLATES THE INTENSITY OF THIS RAINBOW OF COLORS INTO A COMPUTERIZED READOUT.
HOW IS THE TEST PERFORMED
TestsConditions Detected
#AbnormalWear
FuelDilution
Dirt Water CoolantIncorrectOil
OxidationAdditiveDepletion
Glycol Test *
Viscosity * *
Appearance/Odor * * * * *
Spectrometric Analysis
* * * *
Alkaline Reserve * *
Blotter Spot Test * * *
Water Content *
Distillation *
Flash Point *
WEAR METAL ORIGIN TABLE
METAL WEAR POSSIBLE ORIGIN.ALUMINIUM BEARINGS,BLOCKS,BLOWERS,BUSHINGS,
CLUTCHES,PISTONS.
CHROMIUM BEARINGS,PUMPS,RINGS,RODS.
COPPER BEARINGS,BUSHINGS,CLUTHES,WASHERS.
IRON BLOCKS,CRANK SHAFTS, CYLINDERS,DISCS.
SILVER SOLDERS.
TIN PISTONS.
MEASURING INSTRUMENT
ModelT2FMAnalytical Ferrograph. Bi chromatic microscope.Video camera.Video capture card.Image capture software.industrial standard personal computer.
This measure the effectsof Contamination and electro-chemical changes that occur in synthetic and petroleum based oils
FIELD SIGNATURE MAPPING
• The FSM Inspection Tool (FSM) is a new technology for monitoring and inspection of metallic pipes and structures, pipelines and storage vessels
• Reduce life cycle inspection costs
• Reduce inspection time
FIELD PATTERN Sensing pins (electrodes) in an array over the monitored area to detect changes in the electrical field pattern. The voltage = the signature.
Graphical plots indicating the severity and location of corrosion, and calculates actual corrosion and metal loss
INDUSTRIAL ARRANGEMENT
A typical refinery monitors high temperature areas such as heater bends in the distillation unit.
CONCLUSION
SUMMARY OF APPLICABILITY AND CAPABILITY OF VARIOUS NDT TECHNIQUES
NDT TECHNIQUE
DETECTION CAPABILITY
NON CONTACT INSPECTION
AUTOMATED INSPECTION
DEFECT SIZING
VIBRATION VOLUMETRIC POSSIBLE POSSIBLE POSSIBLE
ACOUSTIC EMISSION
VOLUMETRIC POSSIBLE POSSIBLENOT POSSIBLE
I R THERMO- GRAPHY
SURFACE , NEAR SURFACE
POSSIBLE POSSIBLE POSSIBLE
FERROGRAPHY VOLUMETRIC POSSIBLE POSSIBLEPOSSIBLE
F S MSURFACE, NEAR SURFACE
POSSIBLE POSSIBLE POSSIBLE
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