Table of Contents
Advertisement
Before the transducer is placed on the surface, put a small amount of couplant on the surface
of the material. Typically a single drop is sufficient.
2. Place transducer onto the surface of the material to be measured
Press the transducer wearface into the couplant. Moderate pressure on the top of the
transducer using the thumb or index finger is sufficient; it is only necessary to keep the
transducer stationary and the wearface seated flat against the surface of the material.
3. Read display
If six or seven bars of the stability indicator are showing, the display will be reading the correct
thickness of the material directly beneath the transducer.
If the stability indicator has fewer than five bars showing, or the numbers on the display seem
erratic, 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:
•
adjust the gain, or
•
select a different transducer (size or frequency) for the material being measured.
The gauge will perform a number of measurements every second when the transducer is in
contact with the surface of the material. The display is updated as each reading is taken.
4. Remove transducer from surface
The display will show the last measurement made.
Note: Occasionally, a small film of couplant will be drawn out between the transducer and the
surface as the transducer is removed. When this happens, the gauge may perform a measurement
through this couplant film, resulting in a measurement that is larger or smaller than it should be. This
phenomenon can be seen when one thickness value is observed while the transducer is in place,
and another value is observed after the transducer is removed. If this happens, take the reading
again using less couplant.
9 DISPLAY - USING THE B-SCAN VIEW
The B-Scan displays a time based cross sectional view of the material
being tested. This view is commonly used to display the contour of the
blind, or underside, surface of a pipe or tank application. The B-Scan
screen is refreshed once every 7 seconds, from right to left.
If a flaw or pit is located during a scan, the B-Scan will draw the pit on
the screen. The black bar highlighted in the illustration represents the
cross section, or side view of the material. The jagged underside of the
black bar represents the pits and corroded bottom surface of the
material.
It is important that the measurement range on the display is set wide
enough, so that the maximum thickness of the material can be viewed
on the display. In the illustration shown, the measurement range is set
from 0.00 to 1.00 inches. If the material thickness was 1.75 inches, the
underside of the material would not be viewable on the display - all that
would be visible is a black screen from 0.00 inches to 1.00 inches with no view of the bottom contour
at 1.75 inches.
To set the measurement range you must adjust the BSCAN START and BSCAN DEPTH values:
15
0.16
0.39
0.61
0.83
VIEW : BSCA N
SCA N:
O N
B-S T:
VIEW :
0.00 B-D EP:
36
1.00
MODE :
E-E G AIN:
M ED
COL:
A RO W:
1
FILE : #E66
Advertisement
Table of Contents
