Energy ultrasonic

The use of ultrasonic energy is different in on/off switches and in transmitters. Switches act on the attenuation of the acoustic signal in the gap between two crystals, while transmitters measure the time of flight of the ultrasonic pulse. 

Degradation of carbon tetrachloride by photochemical, x-ray, or ultrasonic energy produces the trichloromethyl free radical which on dimeri2ation gives hexachloroethane. Chloroform under strong x-ray irradiation also gives the trichloromethyl radical intermediate and hexachloroethane as final product. 

Sonic Methods A fixed-point level detector based on sonic-propagation characteristics is available for detection of a liquid-vapor interface. This device uses a piezoelectric transmitter and receiver, separated by a short gap. When the gap is filled with liquid, ultrasonic energy is transmitted across the gap, and the receiver actuates a relay. With a vapor filling the gap, the transmission of ultrasonic energy is insufficient to actuate the receiver. 

Other types are available that use sonic energy (from gas streams), ultrasonic energy (electronic), and electrostatic energy, but they are less commonly used in process industries. See Table 14-11 for a sum-maiy of the advantages/disadvantages of the different type units. An expanded discussion is given by Masters [Spray Drying Handbook, Wiley, New York, (1991)]. 

Pelofsky, A.H., Rubber reclamation using ultrasonic energy, US Patent 3,725,314, 1973. 

We have observed a dependence of the yield, polymerization degree, and polydispersity of polysilanes on temperature and also on the power of ultrasonication. In the ultrasonication bath the simplest test of the efficiency of cavitation is the stability of the formed dispersion. It must be remembered that the ultrasonic energy received in the reaction flask placed in the bath depends on the position of the flask in the bath (it is not the same in each bath), on the level of liquid in the bath, on temperature, on the amount of solvent, etc. When an immersion probe is used the cavitation depends on the level of the meniscus in the flask as well. The power is usually adjusted close to 50% of the output level but it varies with the reaction volume, flask shape, and other rection conditions. The immersion-type probe is especially convenient at lower temperatures. 

Scherba G, Weigel RM, O Brien WD (1991) Quantitative assessment of the germicidal efficacy of ultrasonic energy. App Env Microb 57 2079-2084... 

G. W. Proctor and W. H. Tanttila, Influence of ultrasonic energy on the relaxation rate of chlorine nuclei in sodium chlorate, Phys. Rev., 1956, 101, 1757-1762. 

VII-3.7.1 Definition. This is the testing of exposed piping facilities with an instrument capable of detecting the ultrasonic energy generated by escaping gas. The instrument used shall be suitable for the pressure... 

Fairbanks has also studied the effect of ultrasonic energy on the flow characteristics of a poly(methyl methacrylate) melt in a simulated injection moulder. Initially the ultrasound (20 kHz, 0-105 W) was applied either simultaneously or independently to both the extruder tube and the cylinder of the moulder. However, since no discernible effect was observed when ultrasound was applied at the extruder tube, further work with the horn in this position was discontinued. 

Creation of a slip flow at the wall of the cylinder and the entrance to the extruder tube. No doubt this is due to the preferential absorption of the ultrasonic energy at the melt-metal interface which then appears as heat, thereby reducing the viscosity at the wall. 

If transducers are fixed to the external surface of a tube then the tube itself becomes the source of ultrasonic energy. The liquid to be processed can then be passed through the tube and receive sonication directly from the ultrasonically vibrating walls. Two design engineering problems are associated with this type of sonicator (1) the correct mounting of the transducers on the outer tube and (2) the length of the tube must be... 

---