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
vibration
vibration
45%
oil analysis
oil analysis
23%
temperature
rotational speed
temperature
10%
rotational speed
6%
others
4%
acoustic emission
3%
torque
6%
fluorescence
3%
torque
fluorescence
acoustic emission
others
CONDITION BASED MAINTENANCE
2.PREVENTIVE
MAINTENANCE
1.BREAK DOWN
3.PREDICTIVE
NDE TECHNIQUES
1.VIBRATION MONITORING
2.ACOUSTIC EMISSION (AE)
3.INFRARED THERMOGRAPHY (IRT)
4.FERROGRAPHY
5.FIELD SIGNATURE MAPPING (FSM)
VIBRATION MONITORING INSTRUMENTATION
• VIBRATION MEASURING AND ANALYSIS SYSTEM
MACHINE
VIBROMETER
CHANNEL
SELECTOR
FREQUENCY
ANALYSER
fig,(1.a) SIGNAL FLOW DIAGRAM
•
MINI COMPUTERS
•
PROBABILITY DENSITY FUNCTION ANALYSIS (PDF)
•
BY INSPECTION
RECORDER
ANALYSIS OF RESULTS
1. VIBRATION CAUSE IDENTIFICATION
Sl
No
FAULT
FREQUENCY
DIRECTION OF
VIBRATION
1
ROTATING
UNBALANCE
SAME AS RUNNING SPEED
RADIAL
2
MISALIGNMENT
OF BEARINGS
2*SPEED
RADIAL AND
AXIAL
3
ROLLER BEARING
DEFECT
AT BALL OR ROLLER SPEEED RADIAL AND
AXIAL
ULTRA SONIC
FREQUENCIES(20-60KHz)
4.
OIL FILM WHIRL
IN HIGHSPEED
0.5*SPEED
TURBO MACHINES
RADIAL
5
DAMAGED OR
WORN GEARS
RADIAL
No: OF TEETH* RPM
VIBRATION METER (HAND HELD)
SPM VIB-11
by SKF
Vibration Meter : for imbalance, structural weakness, loose parts etc
INDUSTRIAL MACINERY CLASSIFICATION
Class 2: Medium size machines without special foundation
Class 3: Large machines on rigid foundations
Class 4: Large machines on soft foundations.
fig 1.c detection methods of bearing failure
vibration
vibration
45%
oil analysis
oil analysis
23%
temperature
rotational speed
temperature
10%
rotational speed
6%
others
4%
acoustic emission
3%
torque
6%
fluorescence
3%
torque
fluorescence
acoustic emission
others
APPLICATIONOF VIBRATION MONITORING IN
PLANTS
•
•
MONITORING AT ‘ROURKELA STEEL PLANT’
maintenance cost 10-15% of prod: cost
valve
fig2. failure rate of different machineries of plant
others
24%
valve
6%
sliding bearing
6%
seal
7%
gear
7%
sliding
bearing
seal
gear
oil pump
slide way
oil pump
8%
rolling bearing
29%
slide way
13%
rolling
bearing
others
GROWTH THROUGH CBM ACTIVITIES AT RSP
BREAK DOWNS PREVENTED-10-102
120
EQUIPMENTS INCLUDED - 40-140
100
break
downsprevented
60
40
insitu balancing
20
trend line
0
No: of machines
80
savings
94-95
year
95-96
96-97
97-98
98-99
99-00
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)
CASE STUDY
AE DURING HYDROTESTING OF A HORTON
SPHERE
MAX: PRESSURE 22 Kg/cm2
Pressurization (Stage 1)
Random AE activity due to
1. Mechanical rubbing between support
structure and vessel
2. Paint layer peel-off
.
Re pressurization (Stage 2)
No significant AE activity
•AE SIGANLS FROM NEWER AREA
local plastic deformation )
•NO SIGNAL DURING SUBSEQUENT
PRESSURIZATION
(
Fig.2(f) AE monitoring during hydro
testing of Horton sphere
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
I R MEASURING SYSTEMS
VARIOSCAN
3021 ST
Type
Spectral
[µm]
range
8 ... 12
Detector
material
Hg, Cd, Te
Detector cooling
Stirling-cooler
ThermaCAM S60 : Real-Time Thermal
•highly sensitive thermal imaging,
•precision temperature measurement,
•enhanced connectivity options including
•high speed data transfer
•extensive thermal analysis capabilities
CASE STUDY
raw thermo graphic data.
data after removing the noise and vertical
gradient.
correspond to low
strength welds.
high strength welds
data processed for the local gradient in
surface temperature.
Fig setup for infrared testing of lap joints
FERROGRAPHY
1.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
Tests
#
Conditions Detected
Abnormal
Wear
Fuel
Dilution
Dirt
Water
Glycol Test
Incorrect
Oil
Oxidation
Additive
Depletion
*
Viscosity
*
Appearance/Odor
*
Spectrometric
Analysis
Coolant
*
*
*
*
*
*
*
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.
This measure the effects
of Contamination and
electro-chemical changes
that occur in synthetic
and petroleum based oils
Bi chromatic microscope.
Video camera.
Video capture card.
Image capture software.
industrial standard personal computer.
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
Graphical plots indicating the
severity and location of corrosion,
and calculates actual corrosion
and metal loss
Sensing pins (electrodes) in an
array over the monitored
area to detect changes
in the electrical field pattern.
The voltage = the signature.
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
POSSIBLE
NOT
POSSIBLE
I R THERMOGRAPHY
SURFACE ,
NEAR SURFACE
POSSIBLE
POSSIBLE
POSSIBLE
FERROGRAPHY
VOLUMETRIC
POSSIBLE
POSSIBLE
FSM
SURFACE,
NEAR SURFACE
POSSIBLE
POSSIBLE
POSSIBLE
POSSIBLE