Sound Transducers
Unlike other forms of energy, like radiation — which can be harmful to humans and other life forms — ultrasound is merely a form of sound that exceeds the upper audible limits of the average adult. Beginning at 20 kHz and upwards, ultrasonic transducers can make use of these physically shorter wavelengths. As a result, these types of transducers are ideal for use in nondestructive test situations, as well as for the precise measurement of various materials and physical matter, including conducting ultrasounds on human patients.

Frequency Response Function
The high mechanical quality of OURS's piezo transducers ensures that these sandwich-type ultrasonic transducers offer high electro-acoustical efficiency and low heat generation. The mechanical connection of the piezoelectric elements assures a large amplitude output. OURS standard ultrasonic cleaning transducers are available in four frequencies: 28 kHz, 40 kHz, 80 kHz, or 120 kHz. OURS also offers a 50 kHz power transducer that can be used in a variety of applications, including as a fabric cleaner, nebulizer, atomizer, for ultrasonic mixing, or for cell disruptio.

How To Make Ultrasonic Transducers for Ultrasonic Cleaning: Composite Transducers

As is true in many other applications for piezo¬electric materials, an assembly of multiple ceramic elements offers considerable performance and production advantages in ultrasonic cleaning transducers, relative to a single ceramic element. In order to provide the most efficient operation, simplify manufacturing, and reduce costs, more complex transducers intended for ultrasonic power applications usually are a composite of a piezoelectric ceramic center (multiple thin rings or disks of ceramic, for example), encompassed by metallic end or top and bottom parts. Under no liquid load, the mechanical quality factor, Qm , for a well-designed composite transducer will be greater than the correspond¬ing value for an equivalent single piece ceramic transducer, and efficient heat conduction by the metallic portions will ensure a lower operating temperature in the ceramic portion of the transducer. The coupling factor, k, will approach that for a single-piece ceramic transducer.

Ultrasonic Transducer classification:

A. piezoelectric chip classification: Black chip P4 series and yellow chip P8 series;

B. Frequency classification: low frequency series (17-23KHz), intermediate frequency series (25-28KHz), medium and high frequency series (33-60KHz) and high frequency series (68-200KHz);

C. Power classification: 30W series (including 35W), 50W series (including 60W), 100W series (including 80W) and other unconventional power;

D. shape classification: straight column and horn type

Ultrasonic Transducer Frequency selection:

The frequency of the transducer is inversely proportional to the wavelength, and the wavelength is related to the diameter of the cavity (strictly speaking, the nucleation time is longer due to the low frequency), and the diameter of the cavity is related to the explosion pressure. The higher the general frequency, the smaller the wavelength, the smaller the diameter of the cavity, the lower the explosion pressure, but the higher the density of the cavity, the better the permeability.

Based on the above principles:

Low frequency (17 ~ 23KHz): When the dirt of the cleaned material is heavy or difficult to be cleaned, and the explosive impact does not cause much damage to the surface of the cleaned material, the low frequency series transducer should be selected. Commonly used industries are: magnetic industry, steam protection industry, textile industry and so on. Note that the noise of this series is large, preferably sound insulation.

Medium frequency (25 ~ 28KHz): If the dirt of the cleaned material is slightly heavy or the cleaning is difficult and moderate, and the explosive impact does not cause much damage to the surface of the cleaned material, the intermediate frequency series transducer should be selected. This series of industries are the most widely used, and are common in machinery processing industry, electroplating industry, catering industry and so on.

Medium and high frequency (33 ~ 60KHz): When the dirt of the cleaned material is light, the cleaning is easy, or the explosive shock damage to the surface of the cleaned material is required, the medium and high frequency series transducer should be selected. Commonly used industries include precision parts, glass glasses, electronic components, circuit boards, etc.

High Frequency (68-200KHz): The dirt is very light and easy to clean. When the explosive impact is prohibited to damage the surface of the cleaned object, the high frequency series transducer should be selected. Commonly used industries are semiconductors, special high-precision parts, etc.