ZX-5
Ultrasonic Thickness Gauge
7
This is a bottom view of a typical transducer. The two semicircles of the wear face
are visible, as is the barrier separating them. One of the semicircles is responsible
for conducting ultrasonic sound into the material being measured, and the other
semicircle is responsible for conducting the echoed sound back into the transducer.
When the transducer is placed against the material being measured, it is the area
directly beneath the center of the wear face that is being measured.
This is a top view of a typical transducer. Press against the top with the thumb or
index finger to hold the transducer in place. Moderate pressure is sufficient, as it is
only necessary to keep the transducer stationary, and the wear face seated flat
against the surface of the material being measured.
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
ZX-5
has been properly
"zeroed" (see page 15) and set to the correct sound velocity (see page 17), 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
