Case Study: Solvent Ultrasonic Cleaning

L3 Harris EDD (Electron Devices), Torrance, CA, manufactures products such as traveling wave tubes, xenon ion propulsion systems, electronic power conditioners and microwave power modules for a variety of space and defense applications. “Solvent ultrasonic cleaning is used to remove machining oils and particulates from piece parts and brazed assemblies at various stages of the assembly process including preparing surfaces for a subsequent coating,” says Cathy Barnes, the company’s Senior Materials and Process Engineer.    

Explosion Proof Ultrasonic Cleaners Meet Strict Safety Standards

“While ultrasonic cleaning using volatile solvents yields outstanding cleaning results, cleaning with low flash point flammable solvents requires extreme caution including compliance with  National Electric Code (NEC), National Fire Protection Association (NFPA), our plant safety personnel and local fire regulations,” Ms. Barnes says. “For compliance our Torrance facility uses two SOL XP explosion-proof ultrasonic cleaners supplied by Tovatech.”

The 6-gallon capacity SOL XP units operate at 40 kHz ultrasonic frequency and are compliant with all Class I, Division 1 (CID1) code and zone requirements, carry an Intertek ETL Certification and are shipped with a remote electrical panel to be located outside the CID1 envelope. Units are nitrogen inerted for additional fire protection.

SOL XP Explosion-Proof Ultrasonic Cleaner

“Cleaning cycles vary from 5 minutes to 30 minutes depending on the application and legacy approved process,” says Ms. Barnes.  “Optional chillers are used with the SOL XP tanks to ensure safe operation during longer cleaning cycles. The chillers along with tank covers minimize solvent evaporation and the generation of volatile fumes.”

“We’ve found that a combination of ultrasonic cleaning with flammable solvents and aqueous ultrasonic cleaning has been an effective replacement for ozone-depleting solvents such as trichloroethane, Freon and AK225,” she says.     

Safe Ultrasonic Cleaning with Volatile Solvents

As a general rule, whenever you install an ultrasonic cleaner such as the SOL XP for use with volatile solvents you must check with local public safety officials and your plant safety personnel to ensure compliance.

Here are some suggestions:

  • Be sure that solvent vapor cannot come in contact with a potential source of a spark.
  • A suitable exhaust system should be positioned over the ultrasonic cleaner to draw off fumes and protect personnel from inhaling them.
  • Check the unit for damage, and do not operate it if damage is visible.
  • Check the tank and enclosure for damage that could result in leakage.
  • Follow instructions to maintain proper solvent level in the tank.
  • No personal electronics should be used in proximity to the cleaners.
  • Store  spent or unused solvent in approved containers.

More stringent regulations may apply depending on the flammable liquid ultrasonic cleaner you select.  Please contact the Tovatech scientists for expert advice on selecting the correct unit for your operations and information on code compliance.

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