When a measurement fails, the culprit is almost always the coupling between probe and part, not the instrument. Choosing the transducer is the first technical decision of every inspection.
- ✓ Dual element for corrosion, single element for precision
- ✓ Delay line for very thin thicknesses
- ✓ Dedicated probes for high-temperature surfaces
- ✓ Suitable couplant: without it, the pulse does not enter the material
The transducer is the element that converts an electrical pulse into an acoustic wave and vice versa. Its characteristics — frequency, diameter of the active element, presence of a delay line, number of crystals — determine which thicknesses can be measured, with what resolution and on which surfaces.
The first distinction is between dual-element and single-element probes. The former have separate transmitting and receiving elements, tolerate irregular and corroded surfaces and are the standard for corrosion measurement. The latter use a single element and offer higher resolution on well-finished materials.
Need help choosing the right product?
Between probe and part a physical problem remains: air reflects almost all the acoustic energy, so without a coupling medium the pulse does not enter the material. The couplant gel eliminates the air layer, and its choice depends on the surface temperature and the working position.
The in-depth topics of this section
| Topic | What it answers |
|---|---|
| Dual element and single element | Two crystals or one: when each is needed |
| Delay line and thin thicknesses | Why the delay line makes it possible to read thin material |
| High-temperature probes | Measuring on hot surfaces without damaging the transducer |
| Frequency, diameter and near field | How these parameters limit the measurement |
| Couplants and signal quality | Which gel to use and why the choice matters |
How to arrive at the right probe
The choice starts from three data: the material, the expected thickness and the geometry of the surface. An attenuating material requires a lower frequency; a thin thickness requires a higher frequency and a delay line; a strongly curved surface requires a small diameter.
The fourth datum is temperature, which determines both the type of probe and the couplant. The full range of transducers, cables, blocks and couplants is in the Probes and accessories section.
Frequently asked questions
Yes, in contact measurement. The air between probe and part reflects almost all the acoustic energy: without couplant the pulse does not enter the material.
No. Frequency, diameter and construction must be chosen according to material, expected thickness, surface geometry and temperature: a single probe does not cover such different conditions.
It depends on the connector and on compatibility with the instrument’s electronics. If you tell us the model you own, we will confirm which transducers can be used.
Go back to NDT Technologies and Standards or write to us from the Contact page.
Further information and contacts
Systems division and sensor integration partner : www.roder.it
More information about RODER SRL : about us
Contact for general information : info@roder.it
Contact for information about these products : info@roder.it
The information contained on this web page is provided for information purposes only. Although it has been compiled with the utmost care, it does not constitute a contractual offer or a binding commitment to supply. It may contain transcription, translation or typographical errors. For precise and up-to-date information, please contact our company directly.
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