I'm forever imploding bubbles

Apr 07, 2009

The National Physical Laboratory (NPL) has developed the first sensor capable of measuring localized ultrasonic cavitation - the implosion of bubbles in a liquid when a high frequency sound wave is applied. The sensor will help hospitals ensure that their instruments are properly disinfected before they are used on patients. The device recently won the annual Outstanding Ultrasonics Product award from the Ultrasonic Industry Association.

Cavitation is used throughout the NHS by doctors and dentists to clean and disinfect surgical instruments. A high frequency sound wave is passed through a disinfecting liquid to create that implode. The force of each implosion removes contaminate particles from surrounding materials. Cavitation is one of the most effective cleaning processes. There are more than 200 000 places in a teaspoon of tap water where a bubble can emerge and implode, and the process is self-stimulating because the implosion of one bubble creates new sites for further bubbles to emerge. Until now there has been no accurate method of identifying how much cavitation takes place at different locations in a cleaning system, and therefore no measureable way to ensure the cleaning process is effective. The new sensor also means that technicians can fine-tune and optimise equipment so that only the energy required is used, reducing costs and environmental impact.

Previously the only way to measure cavitation rates has been to lower a piece of aluminium foil into the liquid and count the number of 'dents' caused by bubble implosion. NPL's new sensor takes a different approach by monitoring the generated when the bubbles implode. It listens to the bubbles as they collapse and uses the sound to identify how much cavitation is taking place at a given location.

"To spark cavitation we use ultrasonics to 'shout' at a liquid. Our sensor then listens to the response and tells us how much cavitation is taking place as a result of using that particular stimulus," explains Mark Hodnett, a Senior Research Scientist at NPL. "Cavitation is a powerful process but until now users have had no way to measure exactly how loud to shout in order to get a useful amount of bubbles, nor been able to quantify how energetic those bubbles are. They've previously had to rely on trial and error. This is dangerous when you are dealing with cleanliness in medical environments, and a waste of energy. The NPL sensor provides a new tool for improving cleaning systems and aiding instrument hygiene."

Sonic Systems has purchased one of NPL's and say that it fills an important gap in the market. "There is nothing else like the NPL sensor available to sonic equipment manufacturers. We use it as part of our product development process. It has enabled us to verify the cavitation fields inside some of our more complex systems. This has given us the confidence to confirm to customers that our equipment is truly optimised."

Source: National Physical Laboratory

Explore further: Could 'Jedi Putter' be the force golfers need?

add to favorites email to friend print save as pdf

Related Stories

Temperature inside collapsing bubble four times that of sun

Mar 02, 2005

Using a technique employed by astronomers to determine stellar surface temperatures, chemists at the University of Illinois at Urbana-Champaign have measured the temperature inside a single, acoustically driven collapsing ...

New finding bubbles to surface, challenging old view

Aug 20, 2007

Chemical engineers have discovered a fundamental flaw in the conventional view of how liquids form bubbles that grow and turn into vapors, which takes place in everything from industrial processes to fizzing champagne.

Measuring sound with a nanoscopic air bubble

Dec 04, 2008

(PhysOrg.com) -- It will soon be possible to measure ultrasonic sound using water, air, light and nanotechnology – over a hundred times more accurately than with existing sensors.

Researchers solve mystery of attractive surfaces

Aug 02, 2006

When smooth surfaces that hate water approach each other underwater, scientists have observed that they snap into contact. This is apparently due to attractive forces that extend for tens to hundreds of nanometers.

Recommended for you

Could 'Jedi Putter' be the force golfers need?

Apr 18, 2014

Putting is arguably the most important skill in golf; in fact, it's been described as a game within a game. Now a team of Rice engineering students has devised a training putter that offers golfers audio, ...

Better thermal-imaging lens from waste sulfur

Apr 17, 2014

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

earls
not rated yet Apr 08, 2009
Great, now they can also more accurately analyze cold fusion claims.

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...