TOUR Ultrasonics Group Page ORDER  HOME   Index  2010UnimaxNYC
  Ultrasonic Cleaners, How do Ultrasonic Cleaners work? What is cavitation?

Ultrasonic Cleaners

Ultrasonic cleaners are used to dislodge fine particles that other cleaning methods may not be able to reach or remove.  Ultrasonics are not designed as washers.
It would be contrary to expectations to try and clean grossly dirty instruments with  an ultrasonic cleaner.  Items to be ultrasonic processed must be pre-cleaned.
  • Covering the ultrasonic.

    OSHA Section 9 - IX comments:
    "Although there has been concern about potential infectivity of aerosols generated by dental, medical and laboratory equipment, HBV has not been detected in such aerosols, and risk is posed primarily by large particles of 'spatter' that travel only short distance.(Tr 9/14/89,p.21)"
    "The term 'aerosolization'...has been replaced with 'generation of droplets.'" OSHA Section 9 XI
    "...There has been no documented cases in the literature...of HIV transmission via aerosols..."
    "...To the best of our knowledge...there have been no cases."
    "...Aerosols are not known to present a risk of transmission of blood borne pathogens...Therefore, use of respirators for protection against blood borne pathogens is not recommended.
    "...The current opinion of experts is that, while aerosol transmission is a theoretical possibility, it does not contribute measurably to occupational transmission..."
    "...There are no known instances...nor are other instances known in which airborne particles containing blood-borne pathogens have presented a risk to health care workers."
    "CDC/NIOSH...Aerosols are not known to present a risk of transmission of blood-borne pathogens in the healthcare environment.  There are no known instances...

OSHA intends a distinction between "droplets" and "aerosols"
to make it clear that "droplets" (such as produced by power saws and drills) are what are of concern, not  'aerosolization' (as produced by ultrasonics). As you read further notice the distinction.

"Splattering of blood onto skin or mucous membranes of the face and upper respiratory tract against large droplet splattering is needed. ...glasses, goggles, face shields, and surgical appropriate to the task being performed, can provide that protection." OpCit p.51

Pseudo-scientists put some "marker-dye" in an ultrasonic and observed the "marker dye" was "aerosolized" and deposited on surfaces away from the ultrasonic.  They concluded erroneously that covering the ultrasonic was necessary to prevent the spread of pathogens. The conclusion is not demonstrated by the experiment.

The emphasis by OSHA is to encourage the establishment of procedures that prevent the initial problem before focusing on protection, i.e., work practices and engineering controls.

"Paragraph (d)(2)(xi) requires that all procedures involving blood or other potentially infectious materials shall be performed in such a manner as to minimize splashing, spattering, and generation of droplets of these substances."

"The hierarchy of controls provision, paragraph (d)(2)(i), of this standard requires employers to implement engineering controls and work practices prior to relying on personal protective equipment for protecting employees against exposure" OSHA

Cavitation is the term used to describe the mechanical (physical) vibration effect that occurs when high frequency sound waves are introduced into a solution.
The vibration causes minute vacuum- bubbles to form which when they contact an object and "implode."  The disappearing vacuum is a micro-implosion causing the bubble to disappear pulling its surroundings in with tremendous force.  Fine particles on objects are pulled into the space releasing them from the object and they become suspended in the liquid by the soap.

Plain water does not cavitate strongly.
Ultrasonics work well with a soap solution.

Cost-effective Alconox powder is the oldest preferred cleaner because it rinses clean without leaving residue. It is used in technical applications, medical environments and by tattoo and piercing.
Ink Out Cleaner is a new powerful cleaning liquid that has become popular with a very fast strong action.

  • Tip 1:  Maintain solution level to within 1/2" of top rim of ultrasonic, or as specified in manufacturer's recommendation.
  • Alconox should be mixed with water in a container before using in an untrasonic. 4 Tablespoons per gallon of water.
  • Ink-Out should be mixed 16 parts water per part of Ink-Out concentrate.
  • Tip 2: Always use a basket suspending the object 1/2" or more above the bottom. Never place anything directly on the metal bottom.
  • Tip 3: Ultrasonics do not sterilize or disinfect, they only remove fine particles from items being cleaned and the dirt is then suspend in the solution.  Items should be rinsed and dried before packaging for sterilization.
  • Tip 4: More than 10 minutes of ultrasonic cavitation begins to damage the finish of metal tools including stainless steels.
  • Tip 5: Metal-to-metal contact between tools damages finishes of metals.
  • Tip 6: Don't overload the basket. The fewer the number of items the better it will clean. Never put tools on teh bottom without a basket.

Disposal of used liquid.
Used or contaminated water from ultrasonics should be treated with 10% bleach and then poured into the sanitary sewer system down the toilet being careful to avoid splashing.

It is a violation of OSHA regulations to dispose of untreated contaminated liquids into the sewage system.

It is our opinion that unless you are a Central Service Department or have special facilities to reprocess contaminated tools that can meet hospital standards, you should use disposables. Re-processing in retail environments cannot be justified. Using disposables is the way to go.

Ultrasonic Cleaners, How do Ultrasonic Cleaners work? What is cavitation? Elecrowave Ultrasonics, Grobet, Fabulustre, Sonic, Sovereign Ultrasonic