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Pipe inspection in the industry can prove difficult,
expensive, time consuming and with limited results using common NDT
techniques, such as UT Thickness. Other inspection techniques such as
PIG may be impossible to apply for practical reasons, such as geometry.
Guided Ultrasonic waves provide a new solution for
pipe inspection. The inspection is a very fast pipe screening technique
which provides information about cross section area change in the pipe
together with precise information a to where along the pipe this change
occurs.
How it works
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A ring with the transducers is
placed around the pipe
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No couplant is required
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Usually no surface preparation
required
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Instrumentation is fully portable
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Guided waves are sent in each direction
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Data are collected and stored in
the portable instrument
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Reflections are analysed and results
reported immediately after the test
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Long sections of pipe can be examined
from one location, e.g. 30m on either side of the ring
Capabilities
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Each test is completed within minutes including
results
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Can be performed at elevated temperatures
without taking the pipe out of service up to 125°C.
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100% of the pipe is inspected (within
the diagnostic length of a test)
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Pulse echo type operation provides
information on feature position and approximate size
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Sophisticated analysis aids interpretation
of results
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Minimum insulation removal for testing (1m)
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Difficult-to-inspect areas (such
as roadways) can be screened for defects
| Small Diameter Pipes
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Tested using solid rings
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For pipes 2 - 8 inches diameter
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Can be mounted in less than
a minute
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4 inches clearance needed
around pipe

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Large Diameter Pipes
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Tested using inflatable ring
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For pipes 6 - 48 inches diameter
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Employ conventional foot
pump to inflate
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3 inches clearance needed around
most of pipe

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| Two types of waves can
be used

| Torsional
(twisting of the pipe) |
Longitudinal
(compression of the pipe) |
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A typical weld is completely symmetric and shows up as only
a black curve |

A typical corrosion patch is non-symmetric and is identified
by the presence of a red curve |
Target Applications
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Rapid, full coverage screening
of pipes
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Especially cost effective in difficult
to access locations
– Sleeved road crossings
– Corrosion under
insulation
– Wall penetrations
– Pipe racks
– Rope access
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Can detect local and general metal
loss (greater than 5% of the cross-sectional area). Large cracks
in welds may also be detected. Confirmation of the defect type and
details sizing may be done with other NDT.

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