© 2017 by Proceq SA
18
© 2017 by Proceq SA
19
5.11. 250 kHz Shear Wave Transducers
When measurements with the 250 kHz shear wave transducers are performed, it is crucial to
use the special shear wave coupling paste, otherwise shear waves cannot be properly trans-
mitted into the object under test. The shear wave coupling paste is a non-toxic, water soluble
organic substance of very high viscosity.
Furthermore, we highly recommend using Pundit Link’s waveform display in order to manually
locate the onset of the shear wave echo. Since the latter is always preceded by a relatively
weak longitudinal echo (see Figure below), the transit time determined by Pundit Lab, would
correspond to the longitudinal instead of the shear wave.
Required steps before measurements can be performed
1. Put a small amount of shear wave coupling gel on the transducers.
2. Firmly press the transducers on either side of the 25 µs calibration rod (Part No 710 10
028). Make sure that the coupling gel is properly distributed and that no air is trapped
between the transducer and the calibration rod.
3. Connect the transducers to Pundit Lab.
4. Select the 250 kHz transducer from the list of supported transducers (see Pundit Lab
manual chapter 3 for more details).
5. Zero the instrument as described in the Pundit Lab manual chapter 2.1.
Performing measurements with the 250 kHz shear wave transducers.
Typical echo signal obtained, with an experimental setup.
The first echo arrives at approximately 25.4 µs and corresponds to the weak longitudinal
wave. After 50.6 µs the much stronger shear wave echo appears in the signal.
5.12. Transducer Holder Accessory
This accessory is particularly useful for
compound measurements. (See chapter 5)
The individual transducer holders may be
detached and used separately helping to
reduce the physical strain when carrying
out extensive measurements.
6. Technical Specifications
Transit time Measurement
Range
0.1 – 9999 µs Auto ranging.
Resolution
0.1 µs
Display
79 x 21 mm passive matrix OLED
Transmitter
Optimized energizing pulse 125 V, 250 V, 350 V, 500 V, AUTO
Receiver
Selectable gain steps
Pundit Lab
1x, 10x, 100x, AUTO
Selectable gain steps
Pundit Lab
+
1x, 2x, 5x, 10x, 20x, 50x, 100x, 200x, 500x, 1000x, AUTO
Bandwidth
20 kHz – 500 kHz
Memory
Non volatile, > 500 measured values
Regional Settings
Metric and imperial units supported
Power Supply
Battery
4 x AA batteries ( > 20 hours continuous use)
Mains:
5v, <500mA via USB Charger
PC
5v, <500mA directly via USB cable
Mechanical
Dimensions
172 x 55 x 220 mm
Weight
1.3 kg (incl. batteries)
Environmental conditions
Operating temperature
-10° to 60°C (0° to 140°F)
Humidity
<95% RH, non condensing
IP Classification
IP42
