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Selecting A Cleaning Process And Cleaning Solutions
Before a cleaning system is purchased, the parts to be cleaned should
be submitted for an application analysis where:
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1) The materials of construction, configuration,
and quantity of the parts to be cleaned are identified.
2) The soils to be removed are identified and analyzed.
3) The cleaning approach to be used, either aqueous or
solvent, is determined and trials undertaken. |
Only then can an appropriate ultrasonic cleaning system, designed
for the cleaning process and the cleaning solution, be provided.
Choosing A Chemistry
While all of a liquid's physical properties will have an effect
on ultrasonic cleaning, the effects of vapor pressure, surface tension,
viscosity, and density are the most pronounced. Since temperature
influences these properties, it also has influence on the effectiveness
of cavitation.
Considering the effects of these four key physical properties on
cavitation, studies have shown that high density, low viscosity,
and middle range surface tension and vapor pressure are the ideal
conditions for most intense cavitation. Due to temperature effects
on these four physical properties, the most intense cavitation will
be considerably below the liquid's boiling point, but not so low
as to get into the adverse regions of too low vapor pressure or
too high surface tension. Different liquids will have different
temperatures at which cavitation intensity will be the greatest
because of the difference in physical properties and their rate
change in temperatures. Thus the cavitation intensity will be less
either below or above this ideal temperature.
Any cleaning system should be designed for use with the cleaning
solution. Aqueous systems usually consist of open tanks in which
the parts to be cleaned are immersed. A complex system may consist
of several tanks, incorporating recirculating pump and filter systems,
rinse and drying stages, and other accessories.
Systems designed for use with solvents, often ultrasonic vapor degreasers,
usually incorporate means for continuously reclaiming contaminated
solvent. Ultrasonic vapor degreasing is accomplished in an integrated
multiple-compartment system consisting of boiling solvent sumps
and ultrasonic rinse sumps.
The combination of warm solvent vapors and ultrasonic agitation
thoroughly removes oil, grease, wax and other solvent-soluble soils.
The parts emerge from the cleaning process warm, clean and dry.
Theory of Ultrasonics
Selecting A Cleaning Process And Cleaning Solutions
Three Major Factors To Consider
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