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Krautkramer DM4 DL User Manual

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1-10 Issue 05, 01/01 Krautkramer DM4E / DM4 / DM4 DL
Introduction Important remarks about thickness testing
Effects of temperature changes
The sound velocity in the test object changes with the
temperature of the material. Therefore, under certain
conditions, larger measurement errors will be pro-
duced if instrument calibration is made on a cold refer-
ence block and then the thickness measurement car-
ried out on a warm test object. Such measurement
errors can be avoided when calibration is made with a
tempered reference block or when the temperature
effect on the sound velocity is taken into account using
a correction table.
Remaining thickness measurement
Measurement of the remaining thickness on the inside
of eroded or corroded parts such as tubes, containers
or reactors of all types require a suitable measure-
ment device as well as careful handling of the probe.
In any case, the operator should be informed about
the corresponding nominal thickness as well as the
presumed thickness losses.
Probe selection
The probe used for the measurement must be in a
good condition, i.e. it should not have any appreciable
coupling or delay line surface wear. The measurement
range (application range) stated in the probe data
sheets must cover the total thickness range to be
tested. The temperature of the test object must be
within the permitted limits for the selected probe.
Application of couplant
The operator must be conversant with the application
of couplant so that it is applied in the same way for
each measurement. This avoids variations in the layer
thickness of the couplant and the resulting measure-
ment reading errors. The calibration of the instrument
and the actual thickness measurement should be car-
ried out under the same coupling conditions. In doing
this, small amounts of couplant are to be used and a
constant pressure applied to the probe.
With curved coupling surfaces, e.g. tubes, the dual
probe used for the measurement is coupled so that its
acoustic separation layer forms an angle of 90° to the
curvature axis (longitudinal axis of the tube).
1-10 Issue 05, 01/01 Krautkramer DM4E / DM4 / DM4 DL
Introduction Important remarks about thickness testing
Effects of temperature changes
The sound velocity in the test object changes with the
temperature of the material. Therefore, under certain
conditions, larger measurement errors will be pro-
duced if instrument calibration is made on a cold refer-
ence block and then the thickness measurement car-
ried out on a warm test object. Such measurement
errors can be avoided when calibration is made with a
tempered reference block or when the temperature
effect on the sound velocity is taken into account using
a correction table.
Remaining thickness measurement
Measurement of the remaining thickness on the inside
of eroded or corroded parts such as tubes, containers
or reactors of all types require a suitable measure-
ment device as well as careful handling of the probe.
In any case, the operator should be informed about
the corresponding nominal thickness as well as the
presumed thickness losses.
Probe selection
The probe used for the measurement must be in a
good condition, i.e. it should not have any appreciable
coupling or delay line surface wear. The measurement
range (application range) stated in the probe data
sheets must cover the total thickness range to be
tested. The temperature of the test object must be
within the permitted limits for the selected probe.
Application of couplant
The operator must be conversant with the application
of couplant so that it is applied in the same way for
each measurement. This avoids variations in the layer
thickness of the couplant and the resulting measure-
ment reading errors. The calibration of the instrument
and the actual thickness measurement should be car-
ried out under the same coupling conditions. In doing
this, small amounts of couplant are to be used and a
constant pressure applied to the probe.
With curved coupling surfaces, e.g. tubes, the dual
probe used for the measurement is coupled so that its
acoustic separation layer forms an angle of 90° to the
curvature axis (longitudinal axis of the tube).

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Krautkramer DM4 DL Specifications

General IconGeneral
BrandKrautkramer
ModelDM4 DL
CategoryMeasuring Instruments
LanguageEnglish

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