Green or Eco-Friendly Cleaning with Ultrasonic Cleaners

Green Cleaning with Ultrasonic Energy

Ultrasonic energy, in this case using ultrasonic energy for cleaning, has been employed for more than 70  years as a means of removing tough contaminants from virtually any surface that can be safely immersed in a liquid.  But: in the early days this “liquid” was often trichloroethylene or perchloroethylene, definitely not environmentally friendly. Times have changed.  This post provides several suggestions on how you can support green or eco-friendly cleaning with ultrasonic cleaners. 

Why is Ultrasonic Cleaning so Effective?

Two big reasons: ultrasonic cleaning is fast and ultrasonic cleaning is effective.

Billions of microscopic vacuum bubbles created in the ultrasonic cleaning solution implode violently on contact with item being cleaned to blast loose and carry away even the most tenacious contaminants.

Yet the process is so fast that ultrasonic cleaning can be used on delicate and highly finished products such as printed circuit boards, glass and polished aluminum.  

For a more detailed explanation, check this published article in Production Machining.  We also invite you to view our ultrasonic cleaning learning center tutorials on ultrasonic cleaning.

How Ultrasonic Cleaning Supports Green Cleaning

The first reason is suggested in our intro, citing two common chemicals previously used in the process.  By and large these have been replaced by biodegradable cleaning solution concentrates that are diluted with water and mixed in the ultrasonic cleaner tank to perform the cleaning action.

In addition to replacing trichloroethylene and perchloroethylene, biodegradable cleaning solutions are also much more environmentally friendly than using aerosol sprays or solvents in wash tanks to remove grease, grime and other contaminants. In the first example, fumes can be inhaled by workers, in the latter disposing the dirty solvents usually requires first storing on site then contracting with a licensed disposal agency for periodic removal.

Also keep in mind that the concentrates are diluted before use.  An example is elma tec clean A4  – a widely used degreaser with recommended dilutions to 1 to 5% with water.  We’ll cover other applications and cleaning solution recommendations later in this post.

Note that although these cleaning solutions are biodegradable, in every case you should check with local authorities to insure you comply with regulations.  Most suppliers provide product information and material safety data sheets (MSDS) on their ultrasonic cleaning solution products.

Matching Green Friendly Ultrasonic Cleaning Solutions to Requirements

Biodegradable ultrasonic cleaning solution formulas are available to satisfy nearly every cleaning challenge.  Here are just a few examples:

  • In dental clinics elma clean 25 is used to remove alginates and dental plaster; elma clean 35 hygienically cleans used prostheses.
  • In the laboratory neutral elma lab Clean N10 is ideal for instruments of glass, porcelain, ceramics, plastics, metals and metal alloys.  A20sf is perfect for pipettes, burettes, and cylinders of glass, stainless steel, ceramics and plastics.
  • For cleaning printed circuit boards, fine optics and electro-mechanical components use elma tec clean A1 diluted to 3 to 10%.
  • As a “universal cleaner” to quickly remove oil, grease, soot, combustion residues and similar contaminants select elma tec clean A4 diluted to 1 to 5% with water.

For more ideas on how these cleaning solutions solve problems across the board see our ultrasonic cleaning applications pages and selection guide.

Eco-Friendly Formulations to Remove Paints and Coatings  

Eco-friendly removing paints and coatings from all surfaces is fast and easy when using water soluble micro-emulsion formulations suitable for use in either benchtop or industrial ultrasonic cleaning tanks or a conventional wash tank. 

What Makes Micro-Emulsions Different when Removing Paints and Coatings?

Micro-emulsions have the distinct advantage of delaminating coatings from surfaces rather than dissolving them – the latter method resulting in residues building up in solvents commonly used for paint removal tasks.

If the solvents are flammable, additional concerns arise.

Using water-soluble micro-emulsions means the formulations can be filtered, the delaminated coatings separated for disposal and the formulation reused again and again. 

Tovatech now offers three micro-emulsion formulations to remove paint and coatings.  Details are provided on our page featuring non-flammable paint and coating removal options along with recommendations on where they can be employed.

This page also provides recommendations on safely using flammable solvents for paint and coating removal.

How to Extend the Life of your Ultrasonic Cleaner Bath

Unlike the water-soluble emulsions described just above, grease, dirt and other contamination removed during other ultrasonic cleaning processes end up in the bath.  Removing them helps you extend bath life. This is especially important when using large-capacity industrial ultrasonic cleaners.

For some operations replacement time is signaled by visibly dirty solutions and longer cleaning cycles.  In others, notably the removal of grease and oils, it is evidenced by oils rising and floating on the surface. Not as evident are contaminants that settle to the bottom of the tank.

In these instances we’re looking at formulations classified as emulsifying and demulsifying cleaners.  In the former instance oils remain suspended in the cleaning solution where they eventually inhibit efficiency and must be replaced.

In the latter they rise to the surface and can be skimmed off and set aside for later disposal, along with spent solutions, according to local regulations. 

Larger ultrasonic cleaner tanks are available with a skimming ledge that channels floating contaminants into a holding tank for proper disposal.  If an emulsifying cleaning solution is used in industrial-sized units an option is to connect an oil separator to the equipment.  The bath is circulated through the separator where suspended oil is removed and the treated solution returned.

Filters are available to extend ultrasonic cleaning bath life.  These can quickly pay for themselves when used on large capacity units.  The best are dual-filter systems that first remove particles that cause wear on the pump while the second removes smaller contaminants.  Filter replacement time is signaled by a pressure gauge.

Regardless of how you extend the life of your ultrasonic cleaning bath you must include tank cleaning as part of the maintenance procedure.  Follow the manufacturer’s recommendations and in no case use an abrasive when removing sediments on the bottom of the tank.

We hope this post is helpful if you are looking for solutions to green cleaning with ultrasonic energy as well as ideas on selecting, using and maintaining an ultrasonic cleaner bath. You are encouraged to contact the ultrasonic cleaning pros at Tovatech for unbiased answers to your green cleaning challenges and recommendations on the equipment to use.

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Read More