The Phenomenon of
Principle and operationof ultrasound
Cavitation and ultrasonic cleaning
To better understand the principle of ultrasonic cleaning it is necessary to focus on the phenomenon called “Cavitation”.
The Actors in action
To start the cavitation phenomenon and be able to verify it, it is necessary to use:
and its respective
Definition of Cavitation
The “Cavitation” is defined as the physical phenomenon which consists in the cyclic formation, expansion, collapse and implosion of millions of microscopic bubbles of vapor inside a liquid, and which is expressed in a characteristic noise.
When we talk about ultrasound we refer to frequencies above 20,000 Hz, those sound waves above the threshold of normal human hearing. These frequencies are regulated by the current Generator which supplies the respective Immersible Transducers with the energy necessary to generate the phenomenon called Cavitation. Depending on the materials to be treated and the type of contaminant to be removed, the most suitable frequencies are chosen. In ultrasonic cleaning the frequencies can vary from 20 to 200 KHz.
The Vibrant Surface
If the frequencies are regulated by the Generator, then what role does the Immersible Transducer play? It is thanks to the vibrating surface of the Transducer, in contact with the liquid, that the electrical energy produced by the Generator is converted into mechanical oscillations, which correspond to two half waves: a positive one, whose action is of compression and a negative one, whose action is of decompression. This explains why thousands of bubbles form in the liquid which expand, collapse and then implode.
The Cavitation: phase 1
Phase 1. Inside the liquid, the decompression action and the gradual rise in temperature create a multitude of microscopic vapor-laden bubbles (not to be confused with air bubbles). In this phase the bubbles increase and reach their maximum expansion.
The Cavitation: phase 2
Phase 2. Inside the liquid, the compression action and the consequent temperature increase of the gas contained in the bubbles causes them to collapse until they implode. Each implosion discharges its energy on the surface of the immersed objects and acts as countless microbrushes that remove impurities.
Cavitation unit of measurement
In physics, there is no unit of measurement for cavitation. The Watt / liter value, often quoted, refers to the ratio between the power applied to the tank and its volume in liters and not to the value of the cavitation generated which, with the same power and volume, varies according to the chemical and physical parameters of the liquid.
The Cavitometer is an excellent tool that allows you to quickly test the Cavitation and therefore the efficiency of the ultrasonic cleaning. Based on the analysis and processing of the acoustic spectrum generated by the cavitation bubbles, however, it is not able to give absolute values in terms of cavitation units.
Unique benefits of ultrasound
Thorough cleaning: Cavitation bubbles are effective on internal surfaces, cavities and narrow gaps, which are difficult to reach by other methods. Panatronix builds ultrasonic tanks and cleaning plants with unique characteristics, as they meet the needs of its customers, and special, because they can last over time, speed up processes and clean deeply.
Attention to the environment: The use of ultrasound considerably reduces the environmental impact. The higher the ultrasound power, the less chemicals are needed.