Technical Discussions: Re: alternative generation of ultrasound waves

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Re: alternative generation of ultrasound waves
Posted by: Wolfgang Bisle on December 20, 2004 at 14:12:
In Reply to: Re: alternative generation of ultrasound waves posted by : Godfrey Hands , E-mail: godfrey@ndt-consultants.co.uk, on December 20, 2004 at 09:42 :
Some remarks:
Airscan (is a trademark not a method) you mean airborne UT or NCU (nonContactUT) or aircoupled UT:
It is not limited to frquencies in the KHz range. recent systems can go up to 10MHz (Ultran) but realistic around 2..5MHz.
Usually they are Piezo.based with special matching layers, but electrostatic devices are also known, which sometimes work more broadband but they lack a mechanical sturdiness...
Besides the EMAT's which are good for metallics, also Magnetostrictive Probes are used in case of ferrous metalls. (another method)
Finally sparc sound guns are used as a sound transmitter in systems, which operate noncantact using vibrometers for detection (Honeywell, SAM/RAID system)...
so looking a little around one finds a lot more ways to introduce and receive sound then just Piezos

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Re: alternative generation of ultrasound waves kostas papas 16:33 Dec-21-2004 (0)

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----------- Start Original Message ----------- : Some remarks: : Airscan (is a trademark not a method) you mean airborne UT or NCU (nonContactUT) or aircoupled UT: : It is not limited to frquencies in the KHz range. recent systems can go up to 10MHz (Ultran) but realistic around 2..5MHz. : Usually they are Piezo.based with special matching layers, but electrostatic devices are also known, which sometimes work more broadband but they lack a mechanical sturdiness... : Besides the EMAT's which are good for metallics, also Magnetostrictive Probes are used in case of ferrous metalls. (another method) : Finally sparc sound guns are used as a sound transmitter in systems, which operate noncantact using vibrometers for detection (Honeywell, SAM/RAID system)... : so looking a little around one finds a lot more ways to introduce and receive sound then just Piezos ------------ End Original Message ------------

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