Checkline TI-25M User Manual

Page 4

– 21 –

8.3 Measurements On Materials At High Temperatures

When it is necessary to measure wall thickness on surfaces that are in
excess of 200 °F (100 °C), special-purpose high temperature probes should
be used. These probes are built using special materials and techniques that
allow them to withstand high temperatures without damage. Additionally,
care must be taken when performing a “Probe Zero” or “Calibration To
Known Thickness” using a High Temperature probe.

At such elevated temperatures, it is recommended that the user follow these
procedures:

1. Perform a calibration procedure on a sample of known thickness

(refer to section 6.3) with the material temperature at or near the
temperature that will be encountered during measurement.

2. Remove the probe from the hot surface immediately after a “stable”

reading is displayed. Even though the High Temperature Probes are
constructed using materials which can withstand high temperatures,
the probe can begin to heat up, through thermal expansion and
other effects, adversely affecting the accuracy of the measurement.

– 4 –

3.2 Contents Of Kit

The TI-25M is supplied as a complete kit with the following:
a. Gauge
b. Two (2) AA batteries

(installed in gauge)

c. Probe/cable assembly
d. 4 oz. Bottle of coupling fluid
e. NIST-traceable calibration

certificate

f. Operating instruction manual
g. Foam-filled carrying case

3.3 Probe

The probe transmits and receives the ultrasonic sound waves which the
TI-25M uses to calculate the thickness of the material being measured. The
probe must be used correctly in order for the TI-25M to produce accurate
and reliable results.

A small amount of “coupling” fluid, commonly called “couplant” is used to
insure that there are no air gaps between the probe and the material surface.
Grasp the probe by the molded rubber grip and place it on top of the mater-
ial surface. Apply moderate pressure to the top surface of the probe with
your index finger (A) or thumb (B) to stabilize the probe and to keep the
wearface seated flat against the measurement surface.

Probe
Wearface