Dakota Ultrasonics PR-82 User Manual

Page 13

PR-8

Sonic Tester

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

wearface seated flat against the surface of the material being measured.

Making Measurements

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 transmit, 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 (wearface 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

PR-8

has been properly "zeroed" (see page 12) and set to the correct

sound velocity (see page 13), the number in the display will indicate the

actual thickness of the material directly beneath the transducer.