Large-scale ultrasonic cleaning system: Design of a multi-transducer device for boat cleaning (20 kHz)

Abstract

The present study is part of a global project which consists in the development of an automatic cleaning station for immersed boats (cockle, ninepin, etc.) in a self-service mode, associating an innovative ultrasonic device for cleaning with a specific water treatment. The originality of the process is that cleaning is performed by three transducers operating simultaneously at low frequency and moving along the surface, thanks to programmable logic controllers, and that it includes a suction to collect the dirt removed. Therefore, the time required for boat maintenance is shortened, ensuring high quality cleaning without the need for dry docks and avoiding additional pollution in the harbor areas. One of the key points was the evaluation of washing efficiency, as it is really hard to give a quantitative estimation of the dirt removed. To obtain the first design laws, feasibility tests have been carried out on dirty cockle samples and on real boat hulls with a laboratory ultrasonic device. The influence of a large number of parameters was tested such as transducer-probe distance, displacement speed and transmitted power. The obtained data allowed us to design an optimized cleaning device combining high efficiency and speed.

Streaming flow by oscillating bubbles: quantitative diagnostics via particle tracking velocimetry

“…In endodontics, acoustically driven cavitation has been reported to improve root canal cleaning (Macedo et al 2014). Metal workshops use benchtop ultrasonic baths to clean small mechanical components, whereas larger equipment such as turbines or industrial pipelines can be cleaned in dedicated larger baths, or with special transducers able to clean the hull of boats (Mazue et al 2011). Also in the semiconductor industry, cleaning smaller features on microdevice surfaces in cleanroom environments or other high-tech settings (Kim et al 2010;Hauptmann et al 2013;Brems et al 2014) has become a very relevant and economic challenge.…”

Acoustic methods for biofouling control: A review

“…3. Transducers used have included piezoelectric transducers (Branscomb and Rittschof, 1984;Choi et al, 2013;Gavand et al, 2007;Kitamura et al, 1995;Seth et al, 2010Guo et al, 2011a,b, 2012Mazue et al, 2011) and strips/films (Latour and Murphy, 1981;Murphy and Latour, 1979;Wooden and Edelman, 1981), magnetostrictive transducers (Sheherbakov et al, 1974), and audio speakers (Piper, 1977).…”

“…Destructive interference may produce areas, referred to as anti-nodes, where the acoustic energy will be a minimum, potentially reducing the biofouling effect at these areas. The position of the anti-nodes may change with frequency (Piper, 1977;Mazue et al, 2011). The antifouling effectiveness may be expected to decrease with increasing distance from the transducer locations (Sheherbakov et al, 1974).…”

Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

“…On another hand, use of ultrasound is commonly used for cleaning in surface treatment industries, since it is a good way to remove dirt without damaging the products [14][15][16]. In fact, ultrasound is known to induce cavitation phenomena in liquid media, and some of the bubbles generated collapse asymmetrically near the surface.…”

“…Thus, a mechanical cleaning effect is induced due to the high velocity fluid jet delivered while the bubbles collapse, associated with a global stirring effect in the liquid media [17]. Large-scale equipment is possible as shown by recent developments in the field of ship hull cleaning [14], but the heterogeneity of the acoustic field [18] induces a distribution of the power, which needs to be evaluated [17]. Visualization of the actives zones by laser tomography reveals noticeable differences when an obstacle in placed is the propagation field, to be taken into account in the sample positioning [19].…”