Ultrasonic cleaning is widely used for removing particles from surfaces. It is generally agreed that the high energy of implosions of cavitation bubbles break the bonds holding particles to the surface being cleaned and that liquid motion (streaming) carries the particles away once they have been dislodged. However, it is also well known that ultrasonic cavitation and implosion will generate particles as material is eroded from surfaces as cavitation bubbles implode in proximity to them by a process of ultrasonic erosion similar to that seen on a ship's propeller. A g
The CTG Technical Blog is intended as a source of information on subjects related to industrial and precision cleaning technology. The writer of the blog, John Fuchs, has 40+ years of experience covering the entire gamut of cleaning. Mr. Fuchs has extensive knowledge of ultrasonic cleaning technology having been employed by Blackstone-Ney ultrasonics and its predecessors since 1968. The blog is also intended to serve as a forum for discussion of subjects related to cleaning technology. Questions directed to the blog will be responded to either in the blog (if the topic has general interest) or directly by email. Emails with questions about the current blog should be entered in the comments section below. Off-topic questions related to cleaning may be sent to firstname.lastname@example.org.
- q = k A dT / s
- q = heat transfer (W, J/s, Btu/hr)
- A = heat transfer area (m2, ft2)
Heat conductivity is a measure of the ability of a material to transfer heat within itself. For example, if you heat one end of a short piece of copper wire, the heat is quickly distributed throughout the wire by conduction. This can be easily demonstrated using a short piece (1 to 2 inches) of heavy gage copper wire and a small torch or gas lighter. Hold the wire at one end and apply the torch to the other. It won't take long before the copper becomes too hot to hold.
In many industrial cleaning processes it is necessary to exhaust emissions that unavoidably result from the cleaning process. The reasons for exhaust can take on a large range -
A few days ago, I sat down to write what I thought would be a simple explanation of surface tension and how it is measured in the laboratory (a blog which will be published shortly if I can figure all of this out). In doing the normal background research, however, I started to see contradictions that did not align with what I thought I knew about surface tension. The culprit was wettability. Soon I was in a circular argument with myself regarding the two and how to differentiate them.
There has been a lot of buzz lately on the internet regarding work at the Oak Ridge National Laboratory to develop a dryer that uses ultrasonics instead of heat to dry things. The major thrust seems to be to replace the conventional domestic clothes dryer (which uses heat to evaporate water) with one that uses ultrasonics to atomize instead of vaporize water to dry clothes. Claims include drastically reduced energy consumption and shorter drying times. As a result, there has also been some buzz about using the same idea (ultrasonics) to dry parts after ultrasonic
The environment in the area of an industrial cleaning system is often not a "healthy" one for personnel or equipment. Caustic and acidic cleaning chemistries rise as mist above cleaning processes along with humidity and heat. Although our first thought is to protect personnel from these hazards, the equipment can also suffer serious consequences as a result of long term exposure to the unfriendly and corrosive environment. Although the problem is relatively easy to grasp, solutions are a bit more difficult and often prove to be more challenging than one