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PROJECT
(ex: Refinery 04-17)
INSPECTION 1
(ex: Bundle No A1D3FX)
SETUP
TUBE
LIST
DATA
REPORT
INSPECTION 2
INSPECTION X
...
...
Prefix
Frequency
Channels
F1
2 x F90
Array & bobbin
F2
F90
Array & bobbin
F3
F90/2
bobbin
F4
F90/8
bobbin
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PROJECT
(ex: Refinery 04-17)
INSPECTION 1
(ex: Bundle No A1D3FX)
SETUP
TUBE
LIST
DATA
REPORT
INSPECTION 2
INSPECTION X
...
...
Prefix
Frequency
F1
2 x F90
F2
F90
F3
F90/2
F4
F90/8
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

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PROJECT
(ex: Refinery 04-17)
INSPECTION 1
(ex: Bundle No A1D3FX)
SETUP
TUBE
LIST
DATA
REPORT
INSPECTION 2
INSPECTION X
...
...
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#
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PROJECT
(ex: Refinery 04-17)
INSPECTION 1
(ex: Bundle No A1D3FX)
SETUP
TUBE
LIST
DATA
REPORT
INSPECTION 2
INSPECTION X
...
...
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#
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

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PROJECT
(ex: Refinery 04-17)
INSPECTION 1
(ex: Bundle No A1D3FX)
SETUP
TUBE
LIST
DATA
REPORT
INSPECTION 2
INSPECTION X
...
...
"
"
"
"
"
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#
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PROJECT
(ex: Refinery 04-17)
INSPECTION 1
(ex: Bundle No A1D3FX)
SETUP
TUBE
LIST
DATA
REPORT
INSPECTION 2
INSPECTION X
...
...
Excitation Frequency (Hz)
Maximum
Minimum
Maximum
pulling speed (in/s)
20
100
4
100
200
6
200
350
8
350
500
10
500
1000
12
1000
-
20
BW = 8 Hz
SPD = 0.1 m/s
30
0
50
75
BW = 10 Hz
SPD = 0.15 m/s
85
60
135
165
120
BW = 15 Hz
SPD = 0.22 m/s
195
225
180
255
290 310
240
BW = 20 Hz
SPD = 0.3 m/s
355
300
BW = 25 Hz
SPD = 0.35 m/s
365
500
360
420
480
540
600
Frequency (Hz)
Frequency range to avoid
BW = 8 Hz
SPD = 0.1 m/s
30 40 60
0
50
85
BW = 10 Hz
SPD = 0.15 m/s
115 135
100
BW = 15 Hz
SPD = 0.22 m/s
165 205
150
Frequency range allowed
215 240
200
260
295
250
BW = 20 Hz
SPD = 0.3 m/s
305
300
500
350
400
450
Frequency (Hz)
Frequency range to avoid
BW = 25 Hz
SPD = 0.35 m/s
Frequency range allowed
500
550
600
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"
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#
B = B0 e − = B0 e
− d f 0  r
 = d f0  r

B = Magnetic field strength at a depth
corresponding to phase lag ()
B0 = Initial magnetic field strength
 = Phase lag
 = Phase lag
 = 0 r = Permeability
d = Thickness
f = Frequency
 = Conductivity
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Coil layout – Short Double Driver topology
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𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝑑𝑒𝑡𝑒𝑐𝑡𝑎𝑏𝑙𝑒 𝑑𝑒𝑓𝑒𝑐𝑡 =
𝐶𝑒𝑛𝑡𝑒𝑟 − 𝑡𝑜 − 𝑐𝑒𝑛𝑡𝑒𝑟 𝑐𝑜𝑖𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒
4
𝑓=
𝑐𝑚
𝑓
𝑡
1.6 𝑥 𝜌
𝑡2
𝑘𝐻𝑧 𝜌
𝑚𝑚
𝜇𝛺 ∙
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➔
➔
➔
➔
I)
II)
III)
IV)
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VI)
VII)
VIII)
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II)
III)
IV)
V)
VI)
VII)
I)
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V)
→
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VII)
VIII)
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→
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o
o
o
o
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VIII)
IX)
I)
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IV)
V)
I)
II)



-
-
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III)
IV)
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

VI)
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VIII)
IX)
→
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XII)
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XV)
XVI)
i)
ii)
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XVIII)
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➔
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I)
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VII)
VIII)
IX)
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III)
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→
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→
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VI)