Checkline TI-25PX, Руководство по эксплуатации

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V-Path Correction
Dual element delay line transducers have two piezoelectric elements focused towards
one another at a slight angle, mounted on a delay line. One element is used for
transmitting sound, while the other element receives the sound reflection. The two
elements and their delay lines are packaged in a single housing but acoustically isolated
from each other with an insulated sound barrier. This allows the transducer the ability
to achieve very high sensitivity for detecting small defects. Also, the surface of the test
material does not have to be as flat in order to obtain good measurements.
Dual element delay line transducers are have a usable range of 0.025” and up, depending
on the material, frequency, and diameter.
A limitation of dual element delay-line transducers is the V shaped sound path. Because
the sound travels from one element to another, the time versus thickness relationship
is non-linear. Therefore, a correction table in the instruments software is used to
compensate for this error.
Searching for small defects
Dual element delay line transducers are especially useful in searching for small defects.
As a result, this configuration is commonly used for corrosion inspections. The dual
element style transducer will find wall deterioration, pits, cracks, and any porosity
pockets during tank and pipeline inspections.
Dual Element Transducer showing V-path
of signal