Ultrasonic horn

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Ultrasonic Horn is a device used to pass ultrasound into a liquid medium. It basically consists of a transducer. Transducer is a device which consists of a piezoelectric material (http://en.wikipedia.org/wiki/Piezoelectricity), cut properly and sandwitched between metal electrodes. When alternating electrical current passes through the metal electrodes, it caues the piezoelectric material to expand and contract because of the piezoelectric effect of the quartz material. This mechnical contractions and expansions are transferred to a metal rod attached to the piezoelectric crystal. The dimensions of the metal rod (called as extender) and its shape depends upon the node and antinode formation of the passing ultrasonic wave that is created due to continuous expansion and contraction of the piezoelectric material. Thus ultrasound is generated due to continuous expansion and contraction of the quartz material. There is also another way of producing ultrasound. It is called magnetostrictive effect[1]. In this effect, there is a magnetostrictive material which changes its shape in changing magnetic field. Thus when a magnetostrictive material is placed in changing magnetic field, continuous expansion and contraction of the material takes place. This can be transferred as ultrasonic waves into liquid medium. The frequency of the ultrasound generated by these sonic horns range from a few Hz (cycles/sec) to several megahertz. When the ultrasound produced is in the region of 16 KHz up to 1000 KHz, it is called power ultrasound and is used to produce ultrasonic cavitation in the liquid medium. There are several manufacturers of ultrasonic horns in the world. They are mainly Hielscher, Sonics & Materials Inc, Telesonic and Branson Ultrasonics etc. They provide a power ranging from a few watts to several thousand watts. When the ultrasound produced is in the region above 1000 KHz, it is called medical ultrasound and is used for medical applications and dignostic purposes.

[edit] References

1.Title of book "Applied Sonochemistry: The Uses of Power Ultrasound in Chemistry and Processing" Author: T. J. Mason, J. Phillip Lorimer Published 2002 by Wiley-VCH ISBN 3527302050

you can find this book at http://books.google.com/books?id=LhNiLd6U9bYC

3. http://www.hielscher.com/ 4. http://www.sonics.biz/ 5. http://www.sonifier.com/ 6. http://www.telsonic.com/haupt.asp?spr=2

2. Title of book "Cavitation Reaction Engineering " Author: Yatish T. Shah, A. B. Pandit, V. S. Moholkar Published 1999 Springer ISBN 0306461412

You can find this book at http://books.google.com/books?id=oBawyOqH0QIC