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HIGH NOISE ENVIRONMENTS
In noisy environments, it may be necessary to “tune out” unwanted
signals from other areas close to where you are scanning for leaks
or defects. Begin by attaching the air probe extension over the
nose piece. When the extension is attached, the sensing angle of
the instrument is reduced, increasing the directional capability and
reducing the effects of the adjacent noise sources. This allows the
probe to become more directional.
If you suspect that your reading originates from a source other
than what you are scanning, point the probe toward the other sus-
pected source (it may be a compressor V-belt, discharging steam
line, etc.) and slowly decrease the sensitivity until the alarm stops.
Turn the probe back toward direction of the suspected leak or
defect and continue to scan. This step may have to be repeated as
you move around to other locations in search of leaks or defects.
If the probe is close to the internal moving parts of the equipment
and the alarm sounds, push the rubber probe against the housing
of the equipment. If the alarm still sounds, internal friction of mov-
ing parts, not a leak source, may be causing the alarm.
TYPICAL SCANNING METHODS/TIPS
The Marksman
II
provides information in two ways: qualitative,
through the ability to “hear” the signature ultrasounds produced by
various types of equipment, and the ability to see the feedback
level on multiple LEDs.
The air and contact probes are used to optimize the response
depending on the type of inspection being performed. The air
probe is best used for detecting ultrasounds associated with a
pressure leak or an electrical corona, while the contact probe is
best used to detect the ultrasounds generated from within a casing
such as in a gear, bearing, pump, valve or steam trap housing.