Ultrasonic generator

ULTRASONE Ultrasonic atomizer Ultrasonic bonding Ultrasonic devices Ultrasonic fusing Ultrasonic generators Ultrasonic instruments... 

Hansson I, Morch KA, Preece CM (1977) A comparison of ultrasonically generated cavitation erosion and natural flow cavitation erosion. In Proceedings of the Ultrasonics International Conference, Brighton, UK, pp 267-274... 

The use of such different types of piezoelectric materials permits the building of ultrasonic generators of different powers and frequencies for a range of applications. 

Photo and Ultrasonic irradiations were performed with a 200W ultrasonic generator (200 kHz) and a 500W Xe lamp. 

Fig. 12.2 Time dependencies of sonophotocatalytic reaction products from pure water. As powdered photocatalyst, Ti02-A (200mg, Soekawa, Commercial Reagent, rutile-rich type and specific surface area 1.9 m2/g) was used without further treatment. Liquid water (150 cm3, Wake, Distilled water for HPLC was used as reactant and was purged with argon, a Pyrex glass bulb (250-300 cm3) was used as a reactor and was placed m a temperature-controlled bath (EYELA NTT-1200 and ECS-0) all time. After the glass bulb was sealed, the irradiation was carried out under argon atmosphere at 35°C. Photo and ultrasonic irradiations were performed from one side with a 500 W xenon lamp (Ushio, UXL500D-O) and from the bottom with an ultrasonic generator (Kaijo. TA-4021-4611, 20C kHz 200 W), respectively.

An ultrasonicator generates sound waves above 16 kHz, which causes pressure fluctuations to form oscillating bubbles that implode violently generating shock waves. Cell disruption by an ultrasonicator is effective with most cell suspensions and is widely used in the laboratory. However, it is impractical to be used on a large scale due to its high operating cost. 

Review.1 This review includes a discussion of the three types of ultrasonic generators whistlers, cleaning baths, and probe disruptors. The last is the most efficient, but the most expensive. Cleaning baths are inexpensive, but are limited in the temperature range to that of the liquid used, generally water. The review concludes that sonication is most useful in heterogeneous reactions, particularly those of organometallics. The references (235) date from 1953 to the present time, with most in the last 10 years. 

The power of ultrasonic generators is often in the region of 105 Wcm-3. This is sufficient to induce cavitation and generate water or other radicals, and hence the widespread use of ultrasound in medicine should be a matter of possible concern. 

Figure 2. Experimental apparatus for the investigations of acoustic cavitation in a liquid metal. (1) Signal-Generator (2) Amplifier (3) Ultrasonic Generator (4) Transducer (5) Frequency meter (6) Valve voltmeter (7) Sensor of a waveguide stick (8) Recorder (9) Cavitometer (10) Potentiometer (11) Probe (12) Crucible with a melt (13) Source of ultrasound (14) Receiving stick (15) Electric furnace (16) Detector of the first bubble.

Hydrogenation of carbon monoxide was carried out in a slurry-bed reactor, as previously described (ref. 2). Syngas submitted to the slurry reactor was let to react on the catalyst suspended in a liquid carrier (hexadecane). The product gas was partly recycled, and catalyst particles were agitated in the liquid carrier by the recycled gas. An ultrasonic generator was used to prepare the suspension of UFP prior to reaction (ref. 3). 

For ultrasonic treatment, an ultrasonic generator UZDN-2 with frequency 22 kHz and maximum intensity 30 W/cm2 was employed. 

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