Dakota Ultrasonics
8
replenish, unscrew the retaining ring counterclockwise, separate the delay line from
the body, ‘clean both surfaces’, apply a drop of couplant, and reassemble.
Contact Transducer
The single element contact style transducers are commonly used for materials with
an approximate range of 0.040” to the maximum range of the
PZX-7
rated in steel
and depending on the transducers diameter and frequency. The frequency range is
5.0 to 10 MHz, with diameters available at 0.125, 0.250, 0.375 and 0.500 inches.
The measurement modes used with this style of transducer are pulse-echo (P-E) and
echo-echo (E-E).
Measuring
In order for the transducer to do its job, there must be no air gaps between the wear-
face and the surface of the material being measured. This is accomplished with the
use of a "coupling" fluid, commonly called "couplant". This fluid serves to "couple", or
transfer, the ultrasonic sound waves from the transducer, into the material, and back
again. Before attempting to make a measurement, a small amount of couplant
should be applied to the surface of the material being measured. Typically, a single
droplet of couplant is sufficient.
After applying couplant, press the transducer (wear face down) firmly against the
area to be measured. The Stability Indicator should have six or seven bars
darkened, and a number should appear in the display. If the
PZX-7
has been
properly "zeroed" (see page 15), only if P-E mode is currently selected, and set to the
correct sound velocity (see page 16), the number in the display will indicate the
actual thickness of the material directly beneath the transducer.
If the Stability Indicator has fewer than five bars darkened, or the numbers on the
display seem erratic, first check to make sure that there is an adequate film of
couplant beneath the transducer, and that the transducer is seated flat against the
material. If the condition persists, it may be necessary to select a different transducer
(size or frequency) for the material being measured. See page 13 for information on
transducer selection.
While the transducer is in contact with the material that is being measured, the
PZX-7
will perform four measurements every second, updating its display as it does so.
When the transducer is removed from the surface, the display will hold the last
measurement made.
2.10 Top & Bottom End Caps
Summary of Contents for PZX-7
Page 2: ......
