Non-Immersion Ultrasonic Cleaning: An Efficient Green Process for Large Surfaces with Low Water Consumption

Jon Ander Sarasua Miranda,Jose Luis Vilas-Vilela,Leire Ruiz-Rubio,Estibaliz Aranzabe Basterrechea

doi:10.3390/pr9040585

Abstract

Ultrasonic cleaning is a developed and widespread technology used in the cleaning industry. The key to its success over other cleaning methods lies in its capacity to penetrate seemingly inaccessible, hard-to-reach corners, cleaning them successfully. However, its major drawback is the need to immerse the product into a tank, making it impossible to work with large or anchored elements. With the aim of revealing the scope of the technology, this paper will attempt to describe a more innovative approach to cleaning large area surfaces (walls, floors, façades, etc.) which involves applying ultrasonic cavitation onto a thin film of water, which is then deposited onto a dirty surface. Ultrasonic cleaning is an example of the proliferation of green technology, requiring 15 times less water and 115 times less power than conventional high-pressurized waterjet cleaning mechanisms. This paper will account for the physical phenomena that govern this new cleaning mechanism and the competition it poses towards more conventional pressurized waterjet technology. Being easy to use as a measure of success, specular surface cleaning has been selected to measure the degree of cleanliness (reflectance) as a function of the process’s parameters. A design of experiments has been developed in line with the main process parameters: amplitude, gap, and sweeping speed. Regression models have also been used to interpret the results for different degrees of soiling. The work concludes with the finding that the proposed new cleaning technology and process can reach up to 98% total cleanliness, without the use of any chemical product and with very low water and power consumption.

Highlights

Ultrasonic cleaning is based on removing dirt particles through the acoustic cavitation of a liquid
The work presented describes the research performed in the field of non-immersion ultrasonic cleaning for specular surfaces
The effect of each process parameter is different depending on the soiling conditions

Summary

Introduction

Ultrasonic cleaning is based on removing dirt particles through the acoustic cavitation of a liquid. Gallego and Graff [6] acutely reviewed this technology and, in agreement with other authors, such as Fuchs, [7] depending on the size of the bubbles and the implosion intensity, a conclusion was drawn that ultrasounds can remove dirt from a surface and modify the solid surface, or even the liquid itself In this sense, there are many other applications which can and do benefit from acoustic cavitation, such as surface modification [8], catalysis [9], adsorbent regeneration [10], plant extraction [11], immobilization [12], and nano-emulsification [13] Acoustic cavitation is the foundation of one of the most sophisticated cleaning methods on the market, [5] “ultrasonic cleaning.” Gallego and Graff [6] acutely reviewed this technology and, in agreement with other authors, such as Fuchs, [7] depending on the size of the bubbles and the implosion intensity, a conclusion was drawn that ultrasounds can remove dirt from a surface and modify the solid surface, or even the liquid itself.

Methods

Results

Conclusion