NOTE:  This page "evaporated" from my server (perhaps aliens abducted it?) on 13 Sep 99 and has been recreated from a back-up copy - please accept my apologies if I have inadvertently overlooked any typographical errors which might have crept in in the process of recreating the document.

INDEX

PLEASE NOTE:  If some of the internal links on this page refuse to work,
please click on Back and scroll down.

On the main Ultrasonics Page (the first page):

On Ultrasonics Page A

On Ultrasonics Page 1:

On Ultrasonics Page 1A:

On Ultrasonics Page 2 (the preceding page):

On Ultrasonics Page 3 (this page):

On Ultrasonics Page 4:

    Foaming and Aerosoling - moved 28 May 02 from Page 1A.

    Ultrasonic Propulsion (Propulsive Force) - Moving Material.

    Ultrasonic Fountains - Atomization, Nebulization, Humidification,

    Ultrasonics and Nuclear Fusion.

    Quick Links for Ultrasonic Probe Manufacturers (moved 10 Jul 2002).

On the Ultrasonic Cleaning page:

    ULTRASONIC CLEANING {in process}.

On the Ultrasonics Glossary page:

    ULTRASONICS GLOSSARY {in process}.

ULTRASONICS BIBLIOGRAPHY

CALL FOR CONTRIBUTIONS:  I am writing a book on "High-Intensity Ultrasonic Technology and Applications", on the practical application of power (high intensity) ultrasonics, the use of ultrasonic energy to change materials.  Contributions are welcome.

THE CAVITATION BUBBLE

[image from University of Washington, Applied Physics Laboratory (Lawrence Crum, Ph.D.)
- bubble diameter approximately 1mm]

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STERILIZATION and DISINFECTION

AM-1               ULTRASONIC STERILIZATION and DISINFECTION                 16 Jul 97

For over 40 years now, there has been much made of the purported ability of ultrasound, the application of high frequency sound waves, and of ultrasonics, the application of ultrasound at high intensity, to disinfect and sterilize.  Sterilization is defined as absolute killing of all disease organisms, including fungus spores.  Disinfection is not as rigorously defined, and does not necessarily include inactivation of spores.  Much as it pains the author to admit it, ultrasound, and even ultrasonics, do NOT sterilize, by themselves, under normal use in an ultrasonic cleaning tank such as those used by dentists in their offices.  No reputable manufacturer has ever claimed any such property.  Ultrasonic equipment exists that can and routinely does disrupt all bacteria, virii, and fungus under controlled laboratory conditions, but it is a totally different type of device than an ultrasonic cleaner.  Such equipment, termed high intensity probes or disruptors, under such tradenames as SONICATOR, SONIFIER, or VIBRA-CELL, focuses sound on a very small area to disrupt organisms.  Such devices produce energy densities many orders of magnitude higher than that available in even the best ultrasonic cleaning tank.

* One of this country's top three manufacturers of ultrasonic disruptors is Misonix Incorporated of Farmingdale (formerly Heat Systems-Ultrasonics, Inc., 1938 New Highway, Farmingdale, New York 11735, tel. 516-694-9555, FAX 516-694-9412).  The founder of the firm, Howard Alliger, developed the concept of ultrasonic disruption of cells and tissues, used originally primarily to release cell contents such as DNA and enzymes.  Misonix's SONICATOR Ultrasonic Liquid Processor is one of the most widely used in the field.  Another Long Island firm is among a different top three firms making ultrasonic equipment, in this case Sonicor Instruments, Inc. (100 Wartburg Avenue, Copiague, New York 11726, tel. 516-842-3344, FAX 516-842-3389), a major manufacturer of ultrasonic cleaning tanks and vapor degreasers.

A liquid product which, when used in conjunction with an ultrasonic cleaner, or even without, could sterilize instruments was developed here on Long Island by Mr. Alliger, then President of Heat Systems.  In various formulations, the liquid is rated by the EPA as both a disinfectant and sterilant.  For current developments, contact Mr. Alliger at Frontier Pharmaceutical Inc. (formerly Arco Research), 135 Spagnoli Road, Melville, New York  11747, (tel. 631-777-1420, FAX 631-777-1422).  Mr. Alliger also founded Rx Technologies, Inc., a vaccine and diagnostic development company, also at the same address (tel. 631-777-1309, FAX 631-777-1422).

In addition to direct disinfection and sterilization, several surprisingly successful experiments about a decade ago led to the development of a number of highly-proprietary processes in which ozone and other purificants have been introduced into chemical and wastewater flows in the presence of a cavitational field.  The net result has been to greatly improve the efficiency of the chemical action and to provide purified, and even potable, water at economical costs.  The author has two patents (5,032,027 dated 16 July 1991 for an Ultrasonic Fluid Processing Method and 5,026,167 dated 25 Jun 1991 for an Ultrasonic Fluid Processing System, assigned to Heat Systems/Misonix) to this end.

  S. Berliner, III  1998/1997  (all rights reserved)    ULTRASONIC STERILIZATION and DISINFECTION - 16 Jul 97

UM-1             ULTRASONICS, HEARING, and HEALTH              16 Jul 99

Ultrasonic "sickness" appears to be largely psychosomatic, engendered by apprehension or fear of the unknown. Most "awareness" of these processes is due to hearing the "high-audible" components of the noise, not ultrasound. Frequencies used range from 20kHz (20,000 cycles per second) up. The upper threshold of normal human hearing is around 18kHz. Persons able to hear 20kHz and above, including the author, report only a "sensation", rather than discomfort. It should be stressed to concerned individuals that there is no electromagnetic radiation involved, only the creation of sound waves. The acoustic energy passing through the air is at intensities far lower than those emitted by high fidelity equipment; there is no reason, for example, to fear harm to the fetus in utero.

The sound emanating from an open vessel in which an ultrasonic processing horn is being operated is radiated primarily through the air/water interface and secondarily through the walls and bottom of the vessel. Ordinary industrial ear muffs or stopples will block the greater part of this noise, which is primarily in the 5kHz to 8Khz range. Processing often takes place in a fume hood or fume enclosure which will effectively dissipate the sound energy. Special sound reduction cabinets are available to enclose the processor and vessel.

Top quality table-top ultrasonic cleaners should be listed by Underwriters Laboratories, Inc. and certified by the Canadian Standard Association. The sound emanating from ultrasonic cleaners is also primarily radiated through the air/water interface. Any minor change in temperature, depth, or surfactancy of the cleaning solution, or in the bulk of material or number of objects immersed in the tank or in the depth of immersion, will dramatically reduce such noise. The degree to which the cleaning solution has been degassed will also have a significant affect on noise output. Use of a tank cover, preferably with a elastomeric gasket between it and the tank rim, is also helpful.

It is important to isolate the processor, vessel, or cleaning tank from tables, walls, ducts, or other furnishings which could act as, or transmit vibratio ns to, resonant surfaces. Tanks and generators should be mounted on elostomeric feet. Processing convertors and cells should be held in elastomeric clamps. Tubing connections to processing cells should always be flexible, both to minimize sound transmission and to avoid interference with the resonant horn.

Proper attention to such details will prevent the possible annoyance of personnel and resultant complaints about mysterious maladies.

  S. Berliner, III  1999  (all rights reserved)    ULTRASONICS, HEARING, and HEALTH - 16 July 1999

In my response, I noted the sound escaping from an unprotected process can far exceed that and do serious damage, just as I state above.  I also wondered how his damage can be so specifically traced to the ultrasonic equipment.  Hearing loss is a terrible thing and I am in no way making light of his or his friend's or anyone's, but I would need absolute proof, which I frankly do not believe anyone can produce, that the acoustic output of properly-made and -maintained ultrasonic equipment itself, and not of ancillary equipment or processes, is at fault.

I should hasten to add that damaged or badly set up equipment can produce hideous sounds at appalling levels, which I am in the habit of describing as the sound of a "stuck pig" [not that I have ever (happily) heard a pig stuck].  It can be an unbearable screech, and that, in itself, should be more than adequate warning that something is very wrong and that the system should be shut down and examined.  My description usually continues with an analogy to a hot houshold iron; you can test the temperature of the soleplate with your fingertip but you run the risk of a serious burn; the same holds for ultrasonic equipment.  Today's analogy would better be continuing to run a computer after getting a fault warning.  Safety (both of personnel and equipment) always depends on the application of common sense; if it squeals, SHUT IT OFF!

In mechanical operations, such as welding, the tip contact against a hard object can generate terrible levels of sound; protection must be provided.

One major source of internal sound (as opposed to that from the process) is that emanating from a loose or damaged horn or tip or from a failing stack; it can be incredibly loud and piercing (and harmful).

Similarly, I have observed many manufacturers and users of ultrasonic equipment routinely testing in open spaces without acoustic radiation protection; they put their workers at risk and are liable for the consequences.  Thus, again similarly, anyone working under such conditions must either do something about it or quit (or suffer attendant/subsequent hearing loss).

The foregoing is largely based on work at from 20KHz to 120KHz.  Emanations from 15KHz equipment (little-used, currently) are well within the audible range and must be very carefully damped.

These facts are of long standing and are incontrovertible; cavitation, and pre-cavitational effects, cause violent organelle motion, cell disruption, and DNA scission - PERIOD!  If some medical and dental practitioners don't mind such effects occurring in live human tissue, I, for one, do not care to subject myself to their tender ministrations.

KEYWORDS (Applications) INDEX

WHAT'S NEW?

For comparison, here is a typical (and similar) stack used in a heavy-duty industrial cleaning tank or immersible transducer.  Note how the front driver here is a negative-gain device; it' s function is to pass as much energy as possible into the wall/base of the tank at moderate amplitude (too high an amplitude and the tank will hole through from excessive cavitation and parts may be eroded):

Cleaner Stack

Next, allied with AL-2^*, herein, and the environmental paper co-authored with Dr. L. N. Reddi, et al., Feasibility of Ultrasonic Enhancement of Flow in Clayey Sands, Technical Note No. 3291, J. of Environmental Engineering, Environmental Engineering Div., American Society of Civil Engineers, 119, 4, 746-752 (Jul/Aug 1993)., here is the experimental setup used to activate the soil (fluidize the bed), and release bound hydrocarbons:

Soil Remediation Test Arrangement

* - AL-2 - "ULTRASONICS AND FINE PARTICLES -
BENEFICIATION OF SLURRIES AND FINE-PARTICLE SUSPENSIONS
[CERAMICS, COAL & ORES, COATINGS, COLUMN PACKINGS, SINTERING, SLIPS].

These pictures will be integrated into the preceding pages and more detailed explanations provided.

There are also some new ones on the Ultrasonic Cleaning page that tie in with these.

Also new is work on altering skin permeability by ultrasonics as reported in Nature Medicine, March 2000, Vol. 6 No. 3, pp 231 - 356 - "Transdermal monitoring of glucose and other analytes using ultrasound", pp 347 - 350, J. Kost, et al.; an outgrowth of work on varying permeability of membranes, the immediate advantage is painless taking of blood samples for diabetes monitoring.

The School of Biosciences at Cardiff University works on the use of standing waves for particle separation in suspensions.  Their Ultrasonic Bioseparations Research Group has put up a truly excellent poster on this work.