Among the processes occurring in liquid media with ultrasound, cleaning the surface of solids in the ultrasonic medium is successfully applied in numerous industries. Ultrasound is widely taken advantage of for cleaning steel belt, filters, injectors, aluminum or copper wires, cables, etc. Introduction of ultrasonic oscillations in the washing solutions can not only speed up the cleaning process, but also guarantee higher efficiency of cleaning. Due to technical detergent-soluble compounds used in the process of cleaning eliminated are flammable and toxic organic solvents, which undoubtedly leads to improved working conditions, improves the culture of production, and also allows to partially solve the issues of environmental safety.
The effectiveness of ultrasonic cleaning depends on the choice of a variety of parameters, including and physico-chemical properties of the liquid detergent. For right choice of solutions must also consider the nature of the contamination: the degree of adhesion to the surface to be cleaned, the chemical interaction with the detergent solution, the ability to withstand loads microshock (cavitation resistance).
Given the nature of the contamination and the nature of their relationship with the surface the following main types of pollution are distinguished:
- inorganic contaminants, mechanically coupled with the surface (dust, sawdust, shavings of metallic and nonmetallic, carbon black, and so on);
- strongly adherent to the surface mechanically materials (abrasive grains, particles of mineral or metal);
- deposited on the surface (salt cake after treatment in salt baths, scum and so on) – all these types of contamination could be removed due to ultrasonic cleaning equipment.
In industrial use actual the problem of removing pollution of organic nature remains actual, and this is where of the coating or resin bonds mechanically weakly coupled with the surface (dust, sawdust and shavings plastic, carbon black, coal, coke); having a small degree of adhesion to the surface (grease and oil film and lubricants, grinding, polishing and lapping pastes); firmly grip (lacquers, resins, adhesives, paints and enamels).
Dirt film chemically bonded to the surface (oxides, salts and salt-like compounds, including rust and corrosion products) is another problem faced by engineers. To speed up the process of cleaning complex equipment is typically integrated into assembly lines. Nowadays the UK market is oozing with decent leasing options, e.g. Hilsonic Company, a noteworthy manufacturer of ultrasonic cleaners, provides over 20 beneficial contract options.
During the purification process the contaminants properties should be considered: their physical state (liquid or solid, liquid viscosity and the melting point of solid residues); nature of the relationship with the surface contamination of products (polar or non-polar); polymerization degree of pollution in the work components parts at high temperatures (during drawing, stamping, forging and the like. n.); and the presence of small solid particles which fill the grooves, blind and through holes; conglomeration of corrosion products and oxidation pollution.
The most common types of production for most of the dirt and oil are the combination of oil-based contaminants, polishing pastes, inorganic contamination in the form of dust particles, and mechanical, corrosion products, oxides, oxide films.