Eddy current inspection tool which is selectively operable in a discontinuity detection mode and a discontinuity magnitude mode

Patent · 01 January 1983

OSTI ID:864755

Petrini, Richard R ^[1]; Van Lue, Dorin F ^[1]

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1. Livermore, CA

A miniaturized inspection tool, for testing and inspection of metal objects in locations with difficult accessibility, which comprises eddy current sensing equipment (12) with a probe coil (11), and associated coaxial coil cable (13), coil energizing means (21), and circuit means (21, 12) responsive to impedance changes in the coil as effected by induced eddy currents in a test object to produce a data output signal proportional to such changes. The coil and cable are slideably received in the utility channel of the flexible insertion tube 17 of fiberoptic scope 10. The scope 10 is provided with light transmitting and receiving fiberoptics for viewing through the flexible tube, and articulation means (19, 20) for articulating the distal end of the tube and permitting close control of coil placement relative to a test object. The eddy current sensing equipment includes a tone generator 30 for generating audibly signals responsive to the data output signal. In one selected mode of operation, the tone generator responsive to the output signal above a selected level generates a constant single frequency tone for signalling detection of a discontinuity and, in a second selected mode, generates a tone whose frequency is proportional to the difference between the output signal and a predetermined selected threshold level.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• Assignee: Petrini, Richard R. (Livermore, CA);Van Lue, Dorin F. (Livermore, CA)
• Patent Number(s): US 4412177
• OSTI ID: 864755
• Country of Publication: United States
• Language: English

Related Subjects

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10
11
12
13
17
19
20
21
30
accessibility
articulating
articulation
associated
audibly
cable
changes
channel
circuit
circuit means
close
close control
coaxial
coaxial coil
coil
coil cable
comprises
constant
control
current
current inspection
current sensing
currents
data
data output
detection
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difference
difficult
discontinuity
distal
eddy
eddy current
eddy currents
effected
energizing
equipment
fiberoptic
fiberoptics
flexible
flexible tube
frequency
generates
generating
generator
impedance
impedance change
induced
insertion
inspection
inspection tool
level
light
light transmitting
locations
magnitude
means
metal
miniaturized
mode
operable
operation
output
output signal
permitting
placement
predetermined
probe
produce
proportional
provided
received
receiving
receiving fiber
relative
responsive
scope
selected
selected level
selected threshold
selectively
sensing
signal
signal proportional
signalling
signals
single
single frequency
slideably
testing
threshold
threshold level
tone
tone generator
tool
transmitting
tube
utility
viewing