Tn_Us-Ba-E - sauter TN-US Instruction Manual

Ice
Nickel
Plexiglass
Polystyrene
Porcelain
PVC
Quartz glass
Rubber, vulcanized 0.091
Teflon
Water
Appendix B Application Notes
Measuring pipe and tubing
When a piece of pipe is measured to determine the thickness of the pipe wall, the
orientation of the transducer is of importance. If the diameter of the pipe is larger than
approximately 4 inches, measurement should be performed with the transducer ori-
entated in the way that the gap in the surface of the sensor is perpendicular (at right
angle) to the long axis of the pipe.
For smaller pipe diameters, two measurements should be performed, one with the
surface gap of the sensor perpendicular, another with the gap parallel to the long axis
of the pipe. The smaller one of the displayed values should be taken as the thickness
of that point.
Measuring hot surfaces
The sound velocity through a substance is dependent on its temperature. As materi-
als heat up, the velocity of sound through them decreases. In most applications with
surface temperatures of less than 100°C, no special procedures must be observed.
At temperatures above that point, the change in sound velocity of the material being
measured starts having a noticeable effect upon ultrasonic measurement. At such
elevated temperatures it is recommended to first performing a calibration on a sam-
ple piece of known thickness, which is at or near the temperature of the material be-
ing measured. This will allow the instrument to correctly calculate the sound velocity
through the hot material.
When performing measurements on hot surfaces, it may also be necessary to use a
specially constructed high-temperature transducer. These transducers are built of
materials which can withstand high temperatures.
It is also recommended that the sensor has to be left in contact with the surface for a
short time in order to acquire a stable measurement. While the transducer is in con-
tact with the hot surface, it will be heated up and with thermal expansion and other
effects, the accuracy of measurement may adversely be affected.

TN_US-BA-e-1814

0.157 3988
0.222 5639
0.106
2692
0.092
2337
0.230 5842
0.094 2388
0.222 5639
2311
0.056
1422
0.058 1473
17