DUAL MODE PULSE REFLECTOMETRY ACOUSTIC AND ULTRASONIC Hans Felius Director of Sales EMEA
DUAL MODE PULSE REFLECTOMETRY Acoustic and Ultrasonic Probe simultaneously injects 2 types of pulses down the tube Returned echoes generated by defects are recorded and analyzed Patented algorithms identify and report location, type and size of defects Pulses injected in tube Acoustic Pulse Reflectometry (APR) Propagates the air inside the tube Ultrasonic Pulse Reflectometry (UPR) Propagates in the actual material of the tube
VIDEO
ACOUSTIC PULSE REFLECTOMETRY (APR) The probe injects an acoustic pulse which propagates the air inside the tube Returned echoes generated by defects are recorded and analyzed Algorithms identify and report location, type and size of ID defects
TYPICAL APR SIGNALS Each defect has its own signature Impinging pulse Reflection from a local blockage Reflection from a local wall loss Reflection from a hole t Blockage deposits, dents, welding material Wall Loss pitting, erosion
APR ADVANTAGES FOR HEAT EXCHANGERS AND BOILERS Up to 4 inner diameter, any shape or material U-bends, fin-fans, twisted, spiral wound tubes Ferromagnetic and non-ferromagnetic metals, graphite and plastics VERY SENSITIVE TO HOLES, BLOCKAGES / RESTRICTIONS Ultra-fast, non-invasive inspection Less than 10 seconds per tube Fast enough for 100% inspection if/when needed Less expertise required Easy operation with minimal training
APR LIMITATIONS FOR HEAT EXCHANGERS AND BOILERS No OD No crack detection Moderate accuracy in wall loss sizing no circumferential resolution Sensitive to cleanliness
ULTRASONIC PULSE REFLECTOMETRY Unique, high frequency guided wave approach Injects over 400 million ultrasonic pulses into the tube wall Transducer array sends signal and records echoes generated by defects High frequency allows for high longitudinal resolution (few mm) Adds circumferential resolution (lacking in APR) Same general principle of pulse reflectometry as APR (Defect Reflection)
OVERCOMING THE CHALLENGES APPLYING UPR FOR NDT ENGINEERING PHYSICS ALGORITHMS Access only from the ID Rapid dry coupling Multi sensors in small tubes Detect small defects and separate close defects Reach high frequency (~500kHz) Achieve wide bandwidth (50kHz-500kHz) Complex signal processing is imperative High data rate on multiple channels in real time
UPR ADVANTAGES FOR HEAT EXCHANGERS AND BOILERS Sensitive to both ID and OD defects Detects cracks in any orientation Accurate sizing of wall loss circumferential resolution Non-traversing and ultra-fast Can inspect tubes of any shape bent, spiral, serpentine, twisted Easy to operate
UPR LIMITATIONS FOR HEAT EXCHANGERS AND BOILERS Difficult to distinguish holes from deep pits Does not detect blockages Cannot distinguish between ID and OD defects No pure ID information restrictions, bulges
APR + UPR SYNERGY A CLOSER LOOK DEFECT APR UPR APR + UPR Holes Excellent Even for very small holes Good to moderate Hard to distinguish from a deep pit Excellent Blockages Excellent Even for very small blockages Weak Depending on binding to wall Excellent Pits Moderate No circumferential resolution Very good Has circumferential resolution Very good Erosion Cracks Moderate No circumferential resolution sometimes ambiguous with pits No detection Excellent Has circumferential resolution Excellent Any orientation Bulges Excellent No detection Excellent Excellent Excellent
APPLICATIONS LAB TESTING Capability to recreate application challenges found in the field Findings and solutions are verified at end user facilities
RIG #1 PROOF OF CONCEPT Dimensions 19mm x 1.65mm carbon steel 1.2 meters long Defects TWH: 0.66mm, 1.32mm Blockages: 10% Notches: 40% Tapered wear scars: 60% Pits (FBH): 20-80% OD/ID grooves: 20%
SAMPLE SIGNALS FROM TUBE #2 3 Defects Tube # Distance Flaw size Flaw type Notes 2 70 cm 60% 2.77mm diameter OD pit UPR 100 cm 80% 1.98 diameter OD pit UPR 110 cm 1.32mm Through wall hole Both 1.32mm TWH 60%, 2.77mm OD Pit 1.32mm TWH 80%, 1.98mm OD Pit
SAMPLE SIGNALS FROM TUBE #4 3 Defects Tube # Distance Flaw size Flaw type Notes 4 65 cm 40% 4.76mm diameter OD pit under baffle plate UPR 70 cm 10% Internal Blockage APR 100 cm 40% 0.25mm wide, 12.7mm long OD UPR circ notch 10% Internal Blockage 40%, 4.76mm OD pit under baffle plate 40% 0.25mm wide, 12.7mm long OD circ notch
RIG #1 DETECTION SUMMARY Most defects were detected EXCEPT 20% FBH Axial notch Type Amount Detected Missed Through wall holes 4 4 OD pits 6 5 4.76mm x 20% ID pits 1 1 OD groove 2 2 Circ notches 2 2 Axial notches 1 0 0.25mm wide, 12.7mm long OD axial notch Tapered wear scar 1 1 Blockages 2 2
RIG #2 CHALLENGING DEFECTS Dimensions 19.05mm x 1.65mm carbon steel 6 x admiralty brass 6 x stainless steel 1.45 meters long Defects TWH: 0.39 1.32mm FBH: 20-80%, 0.39 4.76mm Notches: 20, 40% 360 degree wear: 5-20%
SAMPLE SIGNALS FROM TUBE #1 4 TWHs Tube # Distance Flaw type Flaw size 1 55 cm TWH 0.39mm 75 cm TWH 0.66mm 105 cm TWH 0.88mm 135 cm TWH 1.32mm 0.39mm TWH 0.66mm TWH 0.88mm TWH 1.32mm TWH APR UPR 0.88mm TWH 1.32mm TWH
SAMPLE SIGNALS FROM TUBE #2 4 FBHs Tube # Distance Flaw type Flaw size 2 60 cm 40% FBH 4.76mm 80 cm 20% FBH 4.76mm 95 cm 60% FBH 2.77mm 120 cm 40% FBH 2.77mm 133 cm 20% FBH 2.77mm UPR (Last FBH is missing) 40% FBH 4.76mm 20% FBH 4.76mm 60% FBH 2.77mm 40% FBH 2.77mm MISSING
SAMPLE SIGNALS FROM TUBE #2 WITH A DIFFERENT FILTER 5 FBHs Tube # Distance Flaw type Flaw size 2 60 cm 40% FBH 4.76mm" 80 cm 20% FBH 4.76mm 95 cm 60% FBH 2.77mm 120 cm 40% FBH 2.77mm 133 cm 20% FBH 2.77mm 40% FBH 4.76mm 20% FBH 4.76mm 60% FBH 2.77mm 40% FBH 2.77mm 20% FBH 2.77mm UPR (Last FBH is detected)
SAMPLE SIGNALS FROM TUBE #3 3 smaller FBHs Tube # Distance Flaw type Flaw size 3 63 80% FBH 1.98mm 77 40% FBH 1.98mm 93 80% FBH 1.19mm 115 40% FBH 1.19mm 130 80% FBH 0.39mm UPR (Last 2 FBHs are missing) 80% FBH 80% FBH 1.98mm 1.19 40% FBH 1.98mm MISSING MISSING
RIG #2 DETECTION SUMMARY DETECTED NOT DETECTED TWHs ALL 4 WERE DETECTED 2 smaller ones by APR only 2 larger ones by both APR and UPR FBHs 4.76mm x 20%, 40% 2.77mm x 20%, 40%, 60% 1.98mm x 40%, 80% 1.19mm x 80% 1.19mm x 40%: 0.39mm x 80% were not detected Circular notches Circular grooves 4 notches, 0.25mm x 10mm, x 15mm, x 30mm, 20% and 40% ALL 5 WERE DETECTED 12.7mm x 360 degrees, 5% - 20% 1 notch, 0.25mm x 5mm, 20%
FIELD RESULTS
CASE STUDY CARBON STEEL HEX FROM OIL REFINERY
CASE STUDY CARBON STEEL HEX Job Setup Time 10 minutes Including creation of tube sheet map # of Tubes Inspected 522 Total Inspection Time 4:35 hours Inspection Rate 116 tubes per hour Defects Found TWH, FBH, Blockage, Notches
APR DETECTION EXAMPLE: TWHs Tube R[3]C[16]: TWH at 0.34m
APR DETECTION EXAMPLE: TWHs Tube R[12]C[1]: 6xTWH
APR DETECTION EXAMPLE: 10% INTERNAL BLOCKAGE Tube R[3]C[4]
UPR DETECTION EXAMPLE: OD NOTCHES Tube R[1]C[3] OD notches
UPR DETECTION EXAMPLE: OD NOTCHES Tube R[1]C[1] OD notches
ADVANCED ALGORITHMS: WAVELET FILTERING UPR measurement of R[1]C[3] before wavelet filtering UPR measurement of R[1]C[3] after wavelet filtering
TUBE CLEANLINESS
CLEANING EXPERIMENT PURPOSE Find minimum cleaning needs for contact point and rest of tube METHOD Clean different tubes on carbon steel HEX with different cleaning conditions Find correlation between cleaning conditions and UPR performance SPECS 722 tubes 19.05mm x 2.10mm carbon steel 6m long
EFFECT ON UPR SIGNAL GENERAL TUBE CLEANING NO CLEANING AFTER (3K PSI)
EFFECT ON UPR SIGNAL SENSOR CONTACT POINT CLEANING NO CLEANING AFTER (3K PSI)
LATEST IMPROVEMENTS TO DUAL MODE METHODOLOGY Mechanical aspects related to consistent contact Design improvements to sensors Electronic noise Algorithms (wavelet filtering)
APR ONLY PROBE
TECHNOLGY ADVANTAGES PULSE REFLECTOMETRY METHOD Ultra-fast speed Significantly faster than conventional inspection techniques Easy to use Single operator inspection consistent, repeatable results Full coverage Any shape u-bends, S shape, twisted Any material ferromagnetic, non-ferromagnetic Large diameter up to 4 boilers Widest detectability Non-traversing solution for ID and OD defects
DUET INSPECTION OPPORTUNITIES APPLICATIONS FOR MULTIPLE MARKETS Maturing this method with the industry Heat Exchangers and Boilers up to 4 OIL & GAS POWER GENERATION CHEMICAL PETROCHEMICAL HVAC PULP & PAPER FOOD & BEVERAGE
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