Checkline TI-25LTX, Руководство по эксплуатации, Страница: 3 / 22

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1.0 INTRODUCTION
The Checkline model TI-25LTX Ultrasonic Thickness Gauge accurately measures the
thickness of steel. This gauge uses the “pulse-echo” principle of ultrasonic testing where
a short ultrasonic signal is transmitted from the probe. The signal travels through the
measurement sample until it is reflected back towards the probe from the back side of
the material. The elapsed time for the complete cycle is measured and converted to an
accurate thickness reading.
The TI-25LT Xcan be used to measure the extent of corrosion on the opposite,
inaccessible side of the wall by using the “Subtractive Method.” When the thickness
of the original wall is known, subtracting the thickness reading obtained from the
TI-25LTX will determine the extent of corrosion at the point of probe placement. If
the original wall thickness is not known, test readings should be made along a grid
of equally-spaced points to obtain a profile of the thickness readings. The smallest
thickness reading will locate the area of greatest concern.
TI-25LTX is capable of measuring the thickness of various materials with accuracy
as high as ± 0.004 inches, or ± 0.1 millimeters. The principle advantage of ultrasonic
measurement over traditional methods is that ultrasonic measurements can be performed
with access to only one side of the material being measured.
1.1 Disclaimer
Inherent in ultrasonic thickness measurement is the possibility that the instrument will
use the second rather than the first echo from the back surface of the material being
measured. This may result in a thickness reading that is TWICE what it should be.
Responsibility for proper use of the instrument and recognition of this phenomenon rest
solely with the user of the instrument. Other errors may occur from measuring coated
materials where the coating is insufficiently bonded to the material surface. Irregular
and inaccurate readings may result. Again, the user is responsible for proper use and
interpretation of the measurements acquired.